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	<title>bioRxiv Channel: Centre for Microbiology and Environmental Systems Science </title>
	<link>https://biorxiv.org</link>
	<description>
	This feed contains articles for bioRxiv Channel "Centre for Microbiology and Environmental Systems Science "
	</description>

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	<prism:publicationName>bioRxiv</prism:publicationName>
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	<link>https://biorxiv.org</link>
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	<item rdf:about="https://biorxiv.org/cgi/content/short/2020.06.04.134015v1?rss=1">
<title>
<![CDATA[
Woeseiales transcriptional response in Arctic fjord surface sediment 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/2020.06.04.134015v1?rss=1"
</link>
<description><![CDATA[
Distinct lineages of Gammaproteobacteria clade Woeseiales are globally-distributed in marine sediments, based on metagenomic and 16S rRNA gene analysis. Yet little is known about why they are dominant or their ecological role in Arctic fjord sediments, where glacial retreat is rapidly imposing change. This study combined 16S rRNA gene analysis, metagenome-assembled genomes (MAGs), and genome-resolved metatranscriptomics uncovered the in situ abundance and transcriptional activity of Woeseiales with burial in four shallow sediment sites of Kongsfjorden and Van Keulenfjorden of Svalbard (79{degrees}N). We present five novel Woeseiales MAGs and show transcriptional evidence for metabolic plasticity during burial, including sulfur oxidation with reverse dissimilatory sulfite reductase (dsrAB) down to 4 cm depth and nitrite reduction down to 6 cm depth. A single stress protein, spore protein SP21 (hspA), had a tenfold higher mRNA abundance than any other transcript, and was a hundredfold higher on average than other transcripts. At three out of the four sites, SP21 transcript abundance increased with depth, while total mRNA abundance and richness decreased, indicating a shift in investment from metabolism and other cellular processes to build-up of spore protein SP21. The SP21 gene in MAGs was often flanked by genes involved in membrane-associated stress response. The ability of Woeseiales to shift from sulfur oxidation to nitrite reduction with burial into marine sediments with decreasing access to overlying oxic bottom waters, as well as enter into a dormant state dominated by SP21, may account for its ubiquity and high abundance in marine sediments worldwide, including those of the rapidly shifting Arctic.
]]></description>
<dc:creator>Buongiorno, J.</dc:creator>
<dc:creator>Sipes, K.</dc:creator>
<dc:creator>Wasmund, K.</dc:creator>
<dc:creator>Loy, A.</dc:creator>
<dc:creator>Lloyd, K. G.</dc:creator>
<dc:date>2020-06-05</dc:date>
<dc:identifier>doi:10.1101/2020.06.04.134015</dc:identifier>
<dc:title><![CDATA[Woeseiales transcriptional response in Arctic fjord surface sediment]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2020-06-05</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/2020.10.01.322446v1?rss=1">
<title>
<![CDATA[
Novel taxa of Acidobacteriota involved in seafloor sulfur cycling 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/2020.10.01.322446v1?rss=1"
</link>
<description><![CDATA[
Acidobacteriota are widespread and often abundant in marine sediments, yet their metabolic and ecological properties are poorly understood. Here, we examined metabolisms and distributions of Acidobacteriota in marine sediments of Svalbard by functional predictions from metagenome-assembled genomes (MAGs), amplicon sequencing of 16S rRNA and dissimilatory sulfite reductase (dsrB) genes and transcripts, and gene expression analyses of tetrathionate-amended microcosms. Acidobacteriota were the second most abundant dsrB-harboring (averaging 13%) phylum after Desulfobacterota in Svalbard sediments, and represented 4% of dsrB transcripts on average. We propose two new Acidobacteriota genera, Candidatus Sulfomarinibacter (class Thermoanaerobaculia,  sub-division 23) and Ca. Polarisedimenticola ( sub-division 22), with distinct genetic properties that may explain their distributions in biogeochemically distinct fjord sediments. Ca. Sulfomarinibacter encodes flexible respiratory routes, with potential for oxygen, nitrous oxide, metal-oxide, tetrathionate, sulfur and sulfite/sulfate respiration, and possibly sulfur disproportionation. Potential nutrients and energy include cellulose, proteins, cyanophycin, hydrogen and acetate. A Ca. Polarisedimenticola MAG encodes enzymes to degrade proteins, and to reduce oxygen, nitrate, sulfur/polysulfide and metal-oxides. 16S rRNA gene and transcript profiling showed Ca. Sulfomarinibacter members were relatively abundant and transcriptionally active in sulfidic fjord sediments, while Ca. Polarisedimenticola members were more relatively abundant in metal-rich fjord sediments. Overall, we reveal various physiological features of uncultured marine Acidobacteriota that indicate fundamental roles in seafloor biogeochemical cycling.
]]></description>
<dc:creator>Flieder, M.</dc:creator>
<dc:creator>Buongiorno, J.</dc:creator>
<dc:creator>Herbold, C.</dc:creator>
<dc:creator>Hausmann, B.</dc:creator>
<dc:creator>Rattei, T.</dc:creator>
<dc:creator>Lloyd, K. G.</dc:creator>
<dc:creator>Loy, A.</dc:creator>
<dc:creator>Wasmund, K.</dc:creator>
<dc:date>2020-10-01</dc:date>
<dc:identifier>doi:10.1101/2020.10.01.322446</dc:identifier>
<dc:title><![CDATA[Novel taxa of Acidobacteriota involved in seafloor sulfur cycling]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2020-10-01</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/2020.04.27.061291v1?rss=1">
<title>
<![CDATA[
Anaerobic microbial degradation of protein and lipid macromolecules in subarctic marine sediment 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/2020.04.27.061291v1?rss=1"
</link>
<description><![CDATA[
Microorganisms in marine sediments play major roles in marine biogeochemical cycles by mineralizing substantial quantities of organic matter from decaying cells. Proteins and lipids are abundant components of necromass, yet microorganisms that degrade them remain understudied. Here, we revealed identities, trophic interactions and genomic features of microorganisms that degraded 13C-labelled proteins and lipids in cold anoxic microcosms with sulfidic subarctic marine sediment. Supplemented proteins and lipids were rapidly fermented to various volatile fatty acids within five days. DNA-stable isotope probing (SIP) suggested Psychrilyobacter atlanticus was an important primary degrader of proteins, and Psychromonas members were important primary degraders of both proteins and lipids. Closely related Psychromonas populations, as represented by distinct 16S rRNA gene variants, differentially utilized either proteins or lipids. DNA-SIP also showed 13C-labeling of various Deltaproteobacteria within ten days, indicating trophic transfer of carbon to putative sulfate-reducers. Metagenome-assembled genomes revealed the primary hydrolyzers encoded secreted peptidases or lipases, and enzymes for catabolism of protein or lipid degradation products. Psychromonas were prevalent in diverse marine sediments, suggesting they are important players in organic carbon processing in situ. Together, this study provides an improved understanding of the metabolic processes and functional partitioning of necromass macromolecules among microorganisms in the seafloor.
]]></description>
<dc:creator>Pelikan, C.</dc:creator>
<dc:creator>Wasmund, K.</dc:creator>
<dc:creator>Glombitza, C.</dc:creator>
<dc:creator>Hausmann, B.</dc:creator>
<dc:creator>Herbold, C.</dc:creator>
<dc:creator>Flieder, M.</dc:creator>
<dc:creator>Loy, A.</dc:creator>
<dc:date>2020-04-28</dc:date>
<dc:identifier>doi:10.1101/2020.04.27.061291</dc:identifier>
<dc:title><![CDATA[Anaerobic microbial degradation of protein and lipid macromolecules in subarctic marine sediment]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2020-04-28</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/284430v1?rss=1">
<title>
<![CDATA[
Growth arrest in the active rare biosphere 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/284430v1?rss=1"
</link>
<description><![CDATA[
Microbial diversity in the environment is mainly concealed within the rare biosphere, which is arbitrarily defined as all species with <0.1% relative abundance. While dormancy explains a low-abundance state very well, the cellular mechanisms leading to rare but active microorganisms are not clear. We used environmental systems biology to genomically and metabolically characterize a cosmopolitan sulfate reducer that is of low abundance but highly active in peat soil, where it contributes to counterbalance methane emissions. We obtained a 98%-complete genome of this low-abundance species, Candidatus Desulfosporosinus infrequens, by metagenomics. To test for environmentally relevant metabolic activity of Ca. D. infrequens, anoxic peat soil microcosms were incubated under diverse in situ-like conditions for 36 days and analyzed by metatranscriptomics. Compared to the no-substrate control, transcriptional activity of Ca. D. infrequens increased 56- to 188-fold in incubations with sulfate and acetate, propionate, lactate, or butyrate, revealing a versatile substrate use. Cellular activation was due to a significant overexpression of genes encoding ribosomal proteins, dissimilatory sulfate reduction, and carbon-degradation pathways, but not of genes encoding DNA or cell replication. We show for the first time that a rare biosphere member transcribes metabolic pathways relevant for carbon and sulfur cycling over prolonged time periods while being growth-arrested in its lag phase.nnSignificanceThe microbial rare biosphere represents the largest pool of biodiversity on Earth and constitutes, in sum of all its members, a considerable part of a habitats biomass. Dormancy or starvation are typically used to explain a low-abundance state. We show that low-abundance microorganisms can be highly metabolically active while being growth-arrested over prolonged time periods. We show that this is true for microbial keystone species, such as a cosmopolitan but low-abundance sulfate reducer in wetlands that is involved in counterbalancing greenhouse gas emission. Our results challenge the central dogmas "metabolic activity translates directly into growth" as well as "low abundance equals little ecosystem impact" and provide an important step forward in understanding rare biosphere members relevant for ecosystem functions.
]]></description>
<dc:creator>Hausmann, B.</dc:creator>
<dc:creator>Pelikan, C.</dc:creator>
<dc:creator>Rattei, T.</dc:creator>
<dc:creator>Loy, A.</dc:creator>
<dc:creator>Pester, M.</dc:creator>
<dc:date>2018-03-19</dc:date>
<dc:identifier>doi:10.1101/284430</dc:identifier>
<dc:title><![CDATA[Growth arrest in the active rare biosphere]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2018-03-19</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/518837v1?rss=1">
<title>
<![CDATA[
Diversity decoupled from sulfur isotope fractionation in a sulfate reducing microbial community 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/518837v1?rss=1"
</link>
<description><![CDATA[
The extent of fractionation of sulfur isotopes by sulfate reducing microbes is dictated by genomic and environmental factors. A greater understanding of species-specific fractionations may better inform interpretation of sulfur isotopes preserved in the rock record. To examine whether gene diversity influences net isotopic fractionation in situ, we assessed environmental chemistry, sulfate reduction rates, diversity of putative sulfur metabolizing organisms by 16S rRNA and dissimilatory sulfite reductase (dsrB) gene amplicon sequencing, and net fractionation of sulfur isotopes along a sediment transect of a hypersaline Arctic spring. In situ sulfate reduction rates yielded minimum cell-specific sulfate reduction rates <0.3 x 10-15 moles cell-1 day-1. Neither 16S rRNA nor dsrB diversity indices correlated with relatively constant (38 to 45{per thousand}) net isotope fractionation ({varepsilon}34Ssulfide-sulfate). Measured {varepsilon}34S values could be reproduced in a mechanistic fractionation model if 1-2% of the microbial community (10-60% of Deltaproteobacteria) were engaged in sulfate respiration, indicating heterogeneous respiratory activity within sulfate-metabolizing populations. This model indicated enzymatic kinetic diversity of Apr was more likely to correlate with sulfur fractionation than DsrB. We propose that, above a threshold alpha diversity value, the influence of the specific composition of the microbial community responsible for generating an isotope signal is overprinted by the control exerted by environmental variables on microbial physiology.nnSubject categoriesO_LIIntegrated genomics and post-genomics approaches in microbial ecologynC_LIO_LIMicrobial ecology and functional diversity of natural habitatsnC_LI
]]></description>
<dc:creator>Colangelo, J.</dc:creator>
<dc:creator>Pelikan, C.</dc:creator>
<dc:creator>Herbold, C.</dc:creator>
<dc:creator>Altschuler, I.</dc:creator>
<dc:creator>Loy, A.</dc:creator>
<dc:creator>Whyte, L.</dc:creator>
<dc:creator>Wing, B.</dc:creator>
<dc:date>2019-01-11</dc:date>
<dc:identifier>doi:10.1101/518837</dc:identifier>
<dc:title><![CDATA[Diversity decoupled from sulfur isotope fractionation in a sulfate reducing microbial community]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2019-01-11</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/528695v1?rss=1">
<title>
<![CDATA[
DNA-foraging bacteria in the seafloor 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/528695v1?rss=1"
</link>
<description><![CDATA[
Extracellular DNA is a major macromolecule in global element cycles, and is a particularly crucial phosphorus as well as nitrogen and carbon source for microorganisms in the seafloor. Nevertheless, the identities, ecophysiology and genetic features of key DNA-foraging microorganisms in marine sediments are completely unknown. Here we combined microcosm experiments, stable isotope probing and genome-centric metagenomics to study microbial catabolism of DNA and its sub-components in anoxic marine sediments. 13C-DNA added to sediment microcosms was degraded within ten days and mineralised to 13CO2. Stable isotope probing showed that diverse Candidatus Izemoplasma, Lutibacter, Shewanella, Fusibacteraceae and Nitrincolaceae incorporated DNA-derived 13C-carbon. Genomes representative of the 13C-labelled taxa were recovered and all encoded enzymatic repertoires for catabolism of DNA. Comparative genomics indicated that DNA can be digested by diverse members of the order Candidatus Izemoplasmatales (former Tenericutes), which appear to be specialised DNA-degraders that encode multiple extracellular nucleases. Fusibacteraceae lacked genes for extracellular nucleases but utilised various individual purine- and pyrimidine-based molecules, suggesting they  cheated on liberated sub-components of DNA. Close relatives of the DNA-degrading taxa are globally distributed in marine sediments, suggesting that these poorly understood taxa contribute widely to the key ecosystem function of degrading and recycling DNA in the seabed.
]]></description>
<dc:creator>Wasmund, K.</dc:creator>
<dc:creator>Pelikan, C.</dc:creator>
<dc:creator>Watzka, M.</dc:creator>
<dc:creator>Richter, A.</dc:creator>
<dc:creator>Noel, A. C.</dc:creator>
<dc:creator>Hubert, C. R. J.</dc:creator>
<dc:creator>Rattei, T.</dc:creator>
<dc:creator>Hofmann, T.</dc:creator>
<dc:creator>Herbold, C. W.</dc:creator>
<dc:creator>Loy, A.</dc:creator>
<dc:date>2019-01-23</dc:date>
<dc:identifier>doi:10.1101/528695</dc:identifier>
<dc:title><![CDATA[DNA-foraging bacteria in the seafloor]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2019-01-23</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/661207v1?rss=1">
<title>
<![CDATA[
Glacial runoff promotes deep burial of sulfur cycling-associated microorganisms in marine sediments 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/661207v1?rss=1"
</link>
<description><![CDATA[
Marine fjords with active glacier outlets are hot spots for organic matter burial in the sediments and subsequent microbial mineralization, and will be increasingly important as climate warming causes more rapid glacial melt. Here, we investigated controls on microbial community assembly in sub-arctic glacier-influenced (GI) and non-glacier-influenced (NGI) marine sediments in the Godth[a]bsfjord region, south-western Greenland. We used a correlative approach integrating 16S rRNA gene and dissimilatory sulfite reductase (dsrB) amplicon sequence data over six meters of depth with biogeochemistry, sulfur-cycling activities, and sediment ages. GI sediments were characterized by comparably high sedimentation rates and had  young sediment ages of <500 years even at 6 m sediment depth. In contrast, NGI stations reached ages of approximately 10,000 years at these depths. Sediment age-depth relationships, sulfate reduction rates, and C/N ratios were strongly correlated with differences in microbial community composition between GI and NGI sediments, indicating that age and diagenetic state were key drivers of microbial community assembly in subsurface sediments. Similar bacterial and archaeal communities were present in the surface sediments of all stations, whereas only in GI sediments were many surface taxa also abundant through the whole sediment core. The relative abundance of these taxa, including diverse Desulfobacteraceae members, correlated positively with sulfate reduction rates, indicating their active contributions to sulfur-cycling processes. In contrast, other surface community members, such as Desulfatiglans, Atribacteria and Chloroflexi, survived the slow sediment burial at NGI stations and dominated in the deepest sediment layers. These taxa are typical for the energy-limited marine deep biosphere and their relative abundances correlated positively with sediment age. In conclusion, our data suggests that high rates of sediment accumulation caused by glacier runoff and associated changes in biogeochemistry, promote persistence of sulfur-cycling activity and burial of a larger fraction of the surface microbial community into the deep subsurface.nnContribution to the Field StatementIn most coastal marine sediments organic matter turnover and total energy flux are highest at the surface and decrease significantly with increasing sediment depth, causing depth-dependent changes in the microbial community composition. Glacial runoff in arctic and subarctic fjords alters the composition of the microbial community at the surface, mainly due to different availabilities of organic matter and metals. Here we show that glacial runoff also modifies microbial community assembly with sediment depth. Sediment age was a key driver of microbial community composition in six-meter-long marine sediment cores from the Godth[a]bsfjord region, south-western Greenland. High sedimentation rates at glacier-influenced sediment stations enabled a complex community of sulfur-cycling-associated microorganisms to continuously thrive at high relative abundances from the surface into the sediment subsurface. These communities consisted of putative fermenters, sulfate reducers and sulfur oxidizers, which likely depended on high metal concentrations in the relatively young, glacier-influenced sediments. In non-glacier-influenced sediments with lower sedimentation rates, these sulfur-cycling-associated microorganisms were only present near the surface. With increasing sediment depth these surface microorganisms were largely replaced by other surface microorganisms that positively correlated with sediment age and belong to known taxa of the energy-limited, marine deep biosphere.
]]></description>
<dc:creator>Pelikan, C.</dc:creator>
<dc:creator>Jaussi, M.</dc:creator>
<dc:creator>Wasmund, K.</dc:creator>
<dc:creator>Seidenkrantz, M.-S.</dc:creator>
<dc:creator>Pearce, C.</dc:creator>
<dc:creator>Kuzyk, Z. Z. A.</dc:creator>
<dc:creator>Herbold, C. W.</dc:creator>
<dc:creator>Roy, H.</dc:creator>
<dc:creator>Kjeldsen, K. U.</dc:creator>
<dc:creator>Loy, A.</dc:creator>
<dc:date>2019-06-06</dc:date>
<dc:identifier>doi:10.1101/661207</dc:identifier>
<dc:title><![CDATA[Glacial runoff promotes deep burial of sulfur cycling-associated microorganisms in marine sediments]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2019-06-06</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/154732v1?rss=1">
<title>
<![CDATA[
Bottled aqua incognita: Microbiota assembly and dissolved organic matter diversity in natural mineral waters 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/154732v1?rss=1"
</link>
<description><![CDATA[
BackgroundNon-carbonated natural mineral waters contain microorganisms that regularly grow after bottling despite low concentrations of dissolved organic matter (DOM). Yet, the compositions of bottled water microbiota and organic substrates that fuel microbial activity, and how both change after bottling, are still largely unknown.nnResultsWe performed a multifaceted analysis of microbiota and DOM diversity in twelve natural mineral waters from six European countries. 16S rRNA gene-based analyses showed that less than ten species-level operational taxonomic units (OTUs) dominated the bacterial communities in the water phase and associated with the bottle wall after a short phase of post-bottling growth. Members of the betaproteobacterial genera Curvibacter, Aquabacterium, and Polaromonas (Comamonadaceae) grew in most waters and represent ubiquitous, mesophilic, heterotrophic aerobes in bottled waters. Ultrahigh-resolution mass spectrometry of DOM in bottled waters and their corresponding source waters identified thousands of molecular formulae characteristic of mostly refractory, soil-derived DOM.nnConclusionsThe bottle environment, including source water physicochemistry, selected for growth of a similar low-diversity microbiota across various bottled waters. Relative abundance changes of hundreds of multi-carbon molecules were related to growth of less than ten abundant OTUs. We thus speculate that individual bacteria cope with oligotrophic conditions by simultaneously consuming diverse DOM molecules.
]]></description>
<dc:creator>Lesaulnier, C. C.</dc:creator>
<dc:creator>Herbold, C. W.</dc:creator>
<dc:creator>Pelikan, C.</dc:creator>
<dc:creator>Berry, D.</dc:creator>
<dc:creator>Gerard, C.</dc:creator>
<dc:creator>Le Coz, X.</dc:creator>
<dc:creator>Gagnot, S.</dc:creator>
<dc:creator>Niggemann, J.</dc:creator>
<dc:creator>Dittmar, T.</dc:creator>
<dc:creator>Singer, G. A.</dc:creator>
<dc:creator>Loy, A.</dc:creator>
<dc:date>2017-06-23</dc:date>
<dc:identifier>doi:10.1101/154732</dc:identifier>
<dc:title><![CDATA[Bottled aqua incognita: Microbiota assembly and dissolved organic matter diversity in natural mineral waters]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2017-06-23</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/197269v1?rss=1">
<title>
<![CDATA[
Peatland Acidobacteria with a dissimilatory sulfur metabolism 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/197269v1?rss=1"
</link>
<description><![CDATA[
Sulfur-cycling microorganisms impact organic matter decomposition in wetlands and consequently greenhouse gas emissions from these globally relevant environments. However,their identities and physiological properties are largely unknown. By applying a functional metagenomics approach to an acidic peatland, we recovered draft genomes of seven novel Acidobacteria species with the potential for dissimilatory sulfite (dsrAB, dsrC, dsrD, dsrN, dsrT, dsrMKJOP) or sulfate respiration (sat, aprBA, qmoABC plus dsr genes). Surprisingly, the genomes also encoded dsrL, a unique gene of the sulfur oxidation pathway. Metatranscriptome analysis demonstrated expression of acidobacterial sulfur-metabolism genes in native peat soil and their upregulation in diverse anoxic microcosms. This indicated an active sulfate respiration pathway, which, however, could also operate in reverse for sulfur oxidation as recently shown for other microorganisms. Acidobacteria that only harbored genes for sulfite reduction additionally encoded enzymes that liberate sulfite from organosulfonates, which suggested organic sulfur compounds as complementary energy sources. Further metabolic potentials included polysaccharide hydrolysis and sugar utilization, aerobic respiration, several fermentative capabilities, and hydrogen oxidation. Our findings extend both, the known physiological and genetic properties of Acidobacteria and the known taxonomic diversity of microorganisms with a DsrAB-based sulfur metabolism, and highlight new fundamental niches for facultative anaerobic Acidobacteria in wetlands based on exploitation of inorganic and organic sulfur molecules for energy conservation.
]]></description>
<dc:creator>Hausmann, B.</dc:creator>
<dc:creator>Pelikan, C.</dc:creator>
<dc:creator>Herbold, C. W.</dc:creator>
<dc:creator>Koestlbacher, S.</dc:creator>
<dc:creator>Albertsen, M.</dc:creator>
<dc:creator>Eichorst, S. A.</dc:creator>
<dc:creator>Glavina del Rio, T.</dc:creator>
<dc:creator>Huemer, M.</dc:creator>
<dc:creator>Nielsen, P. H.</dc:creator>
<dc:creator>Rattei, T.</dc:creator>
<dc:creator>Stingl, U.</dc:creator>
<dc:creator>Tringe, S. G.</dc:creator>
<dc:creator>Trojan, D.</dc:creator>
<dc:creator>Wentrup, C.</dc:creator>
<dc:creator>Woebken, D.</dc:creator>
<dc:creator>Pester, M.</dc:creator>
<dc:creator>Loy, A.</dc:creator>
<dc:date>2017-10-02</dc:date>
<dc:identifier>doi:10.1101/197269</dc:identifier>
<dc:title><![CDATA[Peatland Acidobacteria with a dissimilatory sulfur metabolism]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2017-10-02</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/053090v1?rss=1">
<title>
<![CDATA[
Ecogenomics and biogeochemical impacts of uncultivated globally abundant ocean viruses 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/053090v1?rss=1"
</link>
<description><![CDATA[
Ocean microbes drive global-scale biogeochemical cycling1, but do so under constraints imposed by viruses on host community composition, metabolism, and evolutionary trajectories2-5. Due to sampling and cultivation challenges, genome-level viral diversity remains poorly described and grossly understudied in nature such that <1% of observed surface ocean viruses, even those that are abundant and ubiquitous, are  known5. Here we analyze a global map of abundant, double stranded DNA (dsDNA) viruses and viral-encoded auxiliary metabolic genes (AMGs) with genomic and ecological contexts through the Global Ocean Viromes (GOV) dataset, which includes complete genomes and large genomic fragments from both surface and deep ocean viruses sampled during the Tara Oceans and Malaspina research expeditions6,7. A total of 15,222 epi- and mesopelagic viral populations were identified that comprised 867 viral clusters (VCs, approximately genus-level groups8,9). This roughly triples known ocean viral populations10, doubles known candidate bacterial and archaeal virus genera9, and near-completely samples epipelagic communities at both the population and VC level. Thirty-eight of the 867 VCs were identified as the most impactful dsDNA viral groups in the oceans, as these were locally or globally abundant and accounted together for nearly half of the viral populations in any GOV sample. Most of these were predicted in silico to infect dominant, ecologically relevant microbes, while two thirds of them represent newly described viruses that lacked any cultivated representative. Beyond these taxon-specific ecological observations, we identified 243 viral-encoded AMGs in GOV, only 95 of which were known. Deeper analyses of 4 of these AMGs revealed that abundant viruses directly manipulate sulfur and nitrogen cycling, and do so throughout the epipelagic ocean. Together these data provide a critically-needed organismal catalog and functional context to begin meaningfully integrating viruses into ecosystem models as key players in nutrient cycling and trophic networks.
]]></description>
<dc:creator>Simon Roux</dc:creator>
<dc:creator>Jennifer R Brum</dc:creator>
<dc:creator>Bas E. Dutilh</dc:creator>
<dc:creator>Shinichi Sunagawa</dc:creator>
<dc:creator>Melissa B Duhaime</dc:creator>
<dc:creator>Alexander Loy</dc:creator>
<dc:creator>Bonnie T Poulos</dc:creator>
<dc:creator>Natalie Solonenko</dc:creator>
<dc:creator>Elena Lara</dc:creator>
<dc:creator>Julie Poulain</dc:creator>
<dc:creator>Stephane PESANT</dc:creator>
<dc:creator>Stefanie Kandels-Lewis</dc:creator>
<dc:creator>Céline Dimier</dc:creator>
<dc:creator>Marc Picheral</dc:creator>
<dc:creator>Sarah Searson</dc:creator>
<dc:creator>Corinne Cruaud</dc:creator>
<dc:creator>Adriana Alberti</dc:creator>
<dc:creator>Carlos M. M Duarte</dc:creator>
<dc:creator>Josep M M Gasol</dc:creator>
<dc:creator>Dolors Vaqué</dc:creator>
<dc:creator>Tara Oceans Coordinators</dc:creator>
<dc:creator>Peer Bork</dc:creator>
<dc:creator>Silvia G Acinas</dc:creator>
<dc:creator>Patrick Wincker</dc:creator>
<dc:creator>Matthew B Sullivan</dc:creator>
<dc:creator></dc:creator>
<dc:date>2016-05-12</dc:date>
<dc:identifier>doi:10.1101/053090</dc:identifier>
<dc:title><![CDATA[Ecogenomics and biogeochemical impacts of uncultivated globally abundant ocean viruses]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2016-05-12</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/2020.06.09.141952v1?rss=1">
<title>
<![CDATA[
Genomic and kinetic analysis of novel Nitrospinae enriched by cell sorting 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/2020.06.09.141952v1?rss=1"
</link>
<description><![CDATA[
Chemolithoautotrophic nitrite-oxidizing bacteria (NOB) are key players in global nitrogen and carbon cycling. Members of the phylum Nitrospinae are the most abundant, known NOB in the oceans. To date, only two closely affiliated Nitrospinae species have been isolated, which are only distantly related to the environmentally abundant uncultured Nitrospinae clades. Here, we applied live cell sorting, activity screening, and subcultivation on marine nitrite-oxidizing enrichments to obtain novel marine Nitrospinae. Two binary cultures were obtained, each containing one Nitrospinae strain and one alphaproteobacterial heterotroph. The Nitrospinae strains represent two new genera, and one strain is more closely related to environmentally abundant Nitrospinae than previously cultured NOB. With an apparent half-saturation constant of 8.7{+/-}2.5 {micro}M, this strain has the highest affinity for nitrite among characterized marine NOB, while the other strain (16.2{+/-}1.6 {micro}M) and Nitrospina gracilis (20.1{+/-}2.1 {micro}M) displayed slightly lower nitrite affinities. The new strains and N. gracilis share core metabolic pathways for nitrite oxidation and CO2 fixation but differ remarkably in their genomic repertoires of terminal oxidases, use of organic N sources, alternative energy metabolisms, osmotic stress and phage defense. The new strains, tentatively named "Candidatus Nitrohelix vancouverensis" and "Candidatus Nitronauta litoralis", shed light on the niche differentiation and potential ecological roles of Nitrospinae.
]]></description>
<dc:creator>Mueller, A. J.</dc:creator>
<dc:creator>Jung, M.-Y.</dc:creator>
<dc:creator>Strachan, C. R.</dc:creator>
<dc:creator>Herbold, C. W.</dc:creator>
<dc:creator>Kirkegaard, R. H.</dc:creator>
<dc:creator>Wagner, M.</dc:creator>
<dc:creator>Daims, H.</dc:creator>
<dc:date>2020-06-10</dc:date>
<dc:identifier>doi:10.1101/2020.06.09.141952</dc:identifier>
<dc:title><![CDATA[Genomic and kinetic analysis of novel Nitrospinae enriched by cell sorting]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2020-06-10</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/2020.05.27.119446v1?rss=1">
<title>
<![CDATA[
A refined set of rRNA-targeted oligonucleotide probes for in situ detection and quantification of ammonia-oxidizing bacteria 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/2020.05.27.119446v1?rss=1"
</link>
<description><![CDATA[
Ammonia-oxidizing bacteria (AOB) of the betaproteobacterial genera Nitrosomonas and Nitrosospira are key nitrifying microorganisms in many natural and engineered ecosystems. Since many AOB remain uncultured, fluorescence in situ hybridization (FISH) with rRNA-targeted oligonucleotide probes has been one of the most widely used approaches to study the community composition, abundance, and other features of AOB directly in environmental samples. However, the established and widely used AOB-specific 16S rRNA-targeted FISH probes were designed up to two decades ago, based on much smaller rRNA gene sequence datasets than available today. Several of these probes cover their target AOB lineages incompletely and suffer from a weak target specificity, which causes cross-hybridization of probes that should detect different AOB lineages. Here, a set of new highly specific 16S rRNA-targeted oligonucleotide probes was developed and experimentally evaluated that complements the existing probes and enables the specific detection and differentiation of the known, major phylogenetic clusters of betaproteobacterial AOB. The new probes were successfully applied to visualize and quantify AOB in activated sludge and biofilm samples from seven pilot- and full-scale wastewater treatment systems. Based on its improved target group coverage and specificity, the refined probe set will facilitate future in situ analyses of AOB.
]]></description>
<dc:creator>Lukumbuzya, M.</dc:creator>
<dc:creator>Kristensen, J. M.</dc:creator>
<dc:creator>Kitzinger, K.</dc:creator>
<dc:creator>Pommerening-Roeser, A.</dc:creator>
<dc:creator>Nielsen, P. H.</dc:creator>
<dc:creator>Wagner, M.</dc:creator>
<dc:creator>Daims, H.</dc:creator>
<dc:creator>Pjevac, P.</dc:creator>
<dc:date>2020-05-27</dc:date>
<dc:identifier>doi:10.1101/2020.05.27.119446</dc:identifier>
<dc:title><![CDATA[A refined set of rRNA-targeted oligonucleotide probes for in situ detection and quantification of ammonia-oxidizing bacteria]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2020-05-27</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/2021.03.02.433310v1?rss=1">
<title>
<![CDATA[
Ammonia-oxidizing archaea possess a wide range of cellular ammonia affinities 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/2021.03.02.433310v1?rss=1"
</link>
<description><![CDATA[
Nitrification, the oxidation of ammonia to nitrate, is an essential process in the biogeochemical nitrogen cycle. The first step of nitrification, ammonia oxidation, is performed by three, often co- occurring guilds of chemolithoautotrophs: ammonia-oxidizing bacteria (AOB), archaea (AOA), and complete ammonia oxidizers (comammox). Substrate kinetics are considered to be a major niche-differentiating factor between these guilds, but few AOA strains have been kinetically characterized. Here, the ammonia oxidation kinetic properties of 12 AOA representing all major phylogenetic lineages were determined using microrespirometry. Members of the genus Nitrosocosmicus have the lowest substrate affinity of any characterized AOA, which are similar to previously determined affinities of AOB. This contrasts previous assumptions that all AOA possess much higher substrate affinities than their comammox or AOB counterparts. The substrate affinity of ammonia oxidizers correlated with their cell surface area to volume ratios. In addition, kinetic measurements across a range of pH values strongly supports the hypothesis that - like for AOB - ammonia and not ammonium is the substrate for the ammonia monooxygenase enzyme of AOA and comammox. Together, these data will facilitate predictions and interpretation of ammonia oxidizer community structures and provide a robust basis for establishing testable hypotheses on competition between AOB, AOA, and comammox.
]]></description>
<dc:creator>Jung, M.-Y.</dc:creator>
<dc:creator>Sedlacek, C. J.</dc:creator>
<dc:creator>Kits, K. D.</dc:creator>
<dc:creator>Mueller, A. J.</dc:creator>
<dc:creator>Rhee, S.-K.</dc:creator>
<dc:creator>Hink, L.</dc:creator>
<dc:creator>Nicol, G. W.</dc:creator>
<dc:creator>Bayer, B.</dc:creator>
<dc:creator>Lehtovirta-Morley, L.</dc:creator>
<dc:creator>Wright, C. L.</dc:creator>
<dc:creator>de la Torre, J. R.</dc:creator>
<dc:creator>Herbold, C. W.</dc:creator>
<dc:creator>Pjevac, P.</dc:creator>
<dc:creator>Daims, H.</dc:creator>
<dc:creator>Wagner, M.</dc:creator>
<dc:date>2021-03-02</dc:date>
<dc:identifier>doi:10.1101/2021.03.02.433310</dc:identifier>
<dc:title><![CDATA[Ammonia-oxidizing archaea possess a wide range of cellular ammonia affinities]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2021-03-02</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/2020.10.12.336248v1?rss=1">
<title>
<![CDATA[
Sustained nitrogen loss in a symbiotic association of Comammox Nitrospira and Anammox bacteria 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/2020.10.12.336248v1?rss=1"
</link>
<description><![CDATA[
The discovery of complete aerobic and anaerobic ammonia-oxidizing bacteria (Comammox and Anammox) significantly altered our understanding of the global nitrogen cycle. A high affinity for ammonia (Km(app),NH3 {approx} 63nM) and oxygen place the first described isolate, Comammox Nitrospira inopinata in the same trophic category as organisms such as some ammonia-oxidizing archaea. However, N. inopinata has a relatively low affinity for nitrite (Km,NO2 {approx} 449.2M) suggesting it would be less competitive for nitrite than other nitrite-consuming aerobes and anaerobes. We examined the ecological relevance of the disparate substrate affinities by coupling it with Anammox (Nitrospira inopinata and Brocadia anammoxidans, respectively). Synthetic communities were established in hydrogel granules in which Comammox grew in the aerobic outer layer to provide Anammox with nitrite in the inner anoxic core to form dinitrogen gas. This spatial organization was confirmed with FISH imaging, supporting a mutualistic or commensal relationship. Successful co-habitation of Comammox N. inopinata and Anammox in synthetic granules broadens our limited understanding of the interplay between these two species and offers potential biotechnological applications to study any type of bacterial pairings in a systematic and reproducible manner.
]]></description>
<dc:creator>Gottshall, E. Y.</dc:creator>
<dc:creator>Bryson, S. J.</dc:creator>
<dc:creator>Cogert, K. I.</dc:creator>
<dc:creator>Landreau, M.</dc:creator>
<dc:creator>Sedlacek, C. J.</dc:creator>
<dc:creator>Stahl, D. A.</dc:creator>
<dc:creator>Daims, H.</dc:creator>
<dc:creator>Winkler, M.</dc:creator>
<dc:date>2020-10-12</dc:date>
<dc:identifier>doi:10.1101/2020.10.12.336248</dc:identifier>
<dc:title><![CDATA[Sustained nitrogen loss in a symbiotic association of Comammox Nitrospira and Anammox bacteria]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2020-10-12</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/2020.08.20.256677v1?rss=1">
<title>
<![CDATA[
A novel oxidase from Alcaligenes sp. HO-1 oxidizes hydroxylamine to N2 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/2020.08.20.256677v1?rss=1"
</link>
<description><![CDATA[
Hydroxylamine is a key intermediate of microbial ammonia oxidation and plays an important role in the biogeochemical cycling of N-compounds. Hydroxylamine is oxidized to NO or N2O by hydroxylamine oxidases or cytochrome P460 from heterotrophic or autotrophic bacteria, but its enzymatic oxidation to N2 has not yet been observed. Here, we report on the discovery of a novel oxidase that converts hydroxylamine to N2 from the newly isolated heterotrophic nitrifier Alcaligenes strain HO-1. Strain HO-1 accumulated hydroxylamine and produced N2 from ammonia oxidation. Using transcriptome analysis and heterologous expression via fosmid library screening, we identified three genes (dnfABC) of strain HO-1 that enabled E. coli cells not only to produce hydroxylamine from 15N-labelled ammonium but also to further convert it to 15N2. The three genes were individually cloned and expressed, and their translational products DnfA, DnfB, and DnfC were purified. In vitro DnfA bound to hydroxylamine and catalyzed the conversion of hydroxylamine to N2 in the presence of FAD, NADH and O2. Thus, DnfA was identified as a novel hydroxylamine oxidase and catalyzed a previously unknown N-N bond forming reaction with a yet-to-be discovered mechanism. DnfA homologs were detected in different bacterial groups, suggesting that hydroxylamine oxidation to nitrogen might occur in additional microbial taxa.
]]></description>
<dc:creator>Wu, M.-R.</dc:creator>
<dc:creator>Miao, L.-L.</dc:creator>
<dc:creator>Liu, Y.</dc:creator>
<dc:creator>Hou, T.-T.</dc:creator>
<dc:creator>Ai, G.-M.</dc:creator>
<dc:creator>Ma, L.</dc:creator>
<dc:creator>Zhu, H.-Z.</dc:creator>
<dc:creator>Zhu, Y.-X.</dc:creator>
<dc:creator>Gao, X.-Y.</dc:creator>
<dc:creator>Qin, Y.-L.</dc:creator>
<dc:creator>Wu, T.</dc:creator>
<dc:creator>Shen, X.-H.</dc:creator>
<dc:creator>Jiang, C.-Y.</dc:creator>
<dc:creator>Herbold, C. W.</dc:creator>
<dc:creator>Wagner, M.</dc:creator>
<dc:creator>Li, D.-F.</dc:creator>
<dc:creator>Liu, Z.-P.</dc:creator>
<dc:creator>Liu, S.-J.</dc:creator>
<dc:date>2020-08-20</dc:date>
<dc:identifier>doi:10.1101/2020.08.20.256677</dc:identifier>
<dc:title><![CDATA[A novel oxidase from Alcaligenes sp. HO-1 oxidizes hydroxylamine to N2]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2020-08-20</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/2020.03.05.977850v1?rss=1">
<title>
<![CDATA[
Exploring the upper pH limits of nitrite oxidation: diversity, ecophysiology, and adaptive traits of haloalkalitolerant Nitrospira 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/2020.03.05.977850v1?rss=1"
</link>
<description><![CDATA[
Nitrite-oxidizing bacteria of the genus Nitrospira are key players of the biogeochemical nitrogen cycle. However, little is known about their occurrence and survival strategies in extreme pH environments. Here, we report on the discovery of physiologically versatile, haloalkalitolerant Nitrospira that drive nitrite oxidation at exceptionally high pH. Nitrospira distribution, diversity, and ecophysiology were studied in hypo- and subsaline (1.3-12.8 g salt/l), highly alkaline (pH 8.9-10.3) lakes by amplicon sequencing, metagenomics, and cultivation-based approaches. Surprisingly, not only were Nitrospira populations detected, but they were also considerably diverse with presence of members of Nitrospira lineages I, II and IV. Furthermore, the ability of Nitrospira enrichment cultures to oxidize nitrite at neutral to highly alkaline pH of 10.5 was demonstrated. Metagenomic analysis of a newly enriched Nitrospira lineage IV species, "Candidatus Nitrospira alkalitolerans", revealed numerous adaptive features of this organism to its extreme environment. Among them were a sodium-dependent N-type ATPase and NADH:quinone oxidoreductase next to the proton-driven forms usually found in Nitrospira. Other functions aid in pH and cation homeostasis and osmotic stress defense. "Ca. Nitrospira alkalitolerans" also possesses group 2a and 3b [NiFe] hydrogenases, suggesting it can use hydrogen as alternative energy source. These results reveal how Nitrospira cope with strongly fluctuating pH and salinity conditions and expand our knowledge of nitrogen cycling in extreme habitats.
]]></description>
<dc:creator>Daebeler, A.</dc:creator>
<dc:creator>Kitzinger, K.</dc:creator>
<dc:creator>Koch, H.</dc:creator>
<dc:creator>Herbold, C. W.</dc:creator>
<dc:creator>Steinfeder, M.</dc:creator>
<dc:creator>Schwarz, J.</dc:creator>
<dc:creator>Zechmeister, T.</dc:creator>
<dc:creator>Karst, S. M.</dc:creator>
<dc:creator>Albertsen, M.</dc:creator>
<dc:creator>Nielsen, P. H.</dc:creator>
<dc:creator>Wagner, M.</dc:creator>
<dc:creator>Daims, H.</dc:creator>
<dc:date>2020-03-06</dc:date>
<dc:identifier>doi:10.1101/2020.03.05.977850</dc:identifier>
<dc:title><![CDATA[Exploring the upper pH limits of nitrite oxidation: diversity, ecophysiology, and adaptive traits of haloalkalitolerant Nitrospira]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2020-03-06</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/765727v1?rss=1">
<title>
<![CDATA[
Transcriptomic response of Nitrosomonas europaea transitioned from ammonia- to oxygen-limited steady-state growth 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/765727v1?rss=1"
</link>
<description><![CDATA[
Ammonia-oxidizing microorganisms perform the first step of nitrification, the oxidation of ammonia to nitrite. The bacterium Nitrosomonas europaea is the best characterized ammonia oxidizer to date. Exposure to hypoxic conditions has a profound effect on the physiology of N. europaea, e.g. by inducing nitrifier denitrification, resulting in increased nitric and nitrous oxide production. This metabolic shift is of major significance in agricultural soils, as it contributes to fertilizer loss and global climate change. Previous studies investigating the effect of oxygen limitation on N. europaea have focused on the transcriptional regulation of genes involved in nitrification and nitrifier denitrification. Here, we combine steady-state cultivation with whole genome transcriptomics to investigate the overall effect of oxygen limitation on N. europaea. Under oxygen-limited conditions, growth yield was reduced and ammonia to nitrite conversion was not stoichiometric, suggesting the production of nitrogenous gases. However, the transcription of the principal nitric oxide reductase (cNOR) did not change significantly during oxygen-limited growth, while the transcription of the nitrite reductase-encoding gene (nirK) was significantly lower. In contrast, both heme-copper containing cytochrome c oxidases encoded by N. europaea were upregulated during oxygen-limited growth. Particularly striking was the significant increase in transcription of the B-type heme-copper oxidase, proposed to function as a nitric oxide reductase (sNOR) in ammonia-oxidizing bacteria. In the context of previous physiological studies, as well as the evolutionary placement of N. europaeas sNOR with regards to other heme-copper oxidases, these results suggest sNOR may function as a high-affinity terminal oxidase in N. europaea and other AOB.nnImportanceNitrification is a ubiquitous, microbially mediated process in the environment and an essential process in engineered systems such as wastewater and drinking water treatment plants. However, nitrification also contributes to fertilizer loss from agricultural environments increasing the eutrophication of downstream aquatic ecosystems and produces the greenhouse gas nitrous oxide. As ammonia-oxidizing bacteria are the most dominant ammonia-oxidizing microbes in fertilized agricultural soils, understanding their response to a variety of environmental conditions is essential for curbing the negative environmental effects of nitrification. Notably, oxygen limitation has been reported to significantly increase nitric oxide and nitrous oxide production during nitrification. Here we investigate the physiology of the best characterized ammonia-oxidizing bacterium, Nitrosomonas europaea, growing under oxygen-limited conditions.
]]></description>
<dc:creator>Sedlacek, C. J.</dc:creator>
<dc:creator>Giguere, A. T.</dc:creator>
<dc:creator>Dobie, M. D.</dc:creator>
<dc:creator>Mellbye, B. L.</dc:creator>
<dc:creator>Ferrell, R. V.</dc:creator>
<dc:creator>Woebken, D.</dc:creator>
<dc:creator>Sayavedra-Soto, L.</dc:creator>
<dc:creator>Bottomley, P.</dc:creator>
<dc:creator>Daims, H.</dc:creator>
<dc:creator>Wagner, M.</dc:creator>
<dc:creator>Pjevac, P.</dc:creator>
<dc:date>2019-09-11</dc:date>
<dc:identifier>doi:10.1101/765727</dc:identifier>
<dc:title><![CDATA[Transcriptomic response of Nitrosomonas europaea transitioned from ammonia- to oxygen-limited steady-state growth]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2019-09-11</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/096891v1?rss=1">
<title>
<![CDATA[
AmoA-targeted polymerase chain reaction primers for the specific detection and quantification of comammox Nitrospira in the environment 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/096891v1?rss=1"
</link>
<description><![CDATA[
Nitrification, the oxidation of ammonia via nitrite to nitrate, has always been considered to be catalyzed by the concerted activity of ammonia and nitrite-oxidizing microorganisms. Only recently, complete ammonia oxidizers ( comammox), which oxidize ammonia to nitrate on their own, were identified in the bacterial genus Nitrospira, previously assumed to contain only canonical nitrite oxidizers. Nitrospira are widespread in nature, but for assessments of the distribution and functional importance of comammox Nitrospira in ecosystems, cultivation-independent tools to distinguish comammox from strictly nitrite-oxidizing Nitrospira are required. Here we developed new PCR primer sets that specifically target the amoA genes coding for subunit A of the distinct ammonia monooxygenase of comammox Nitrospira. While existing primers capture only a fraction of the known comammox amoA diversity, the new primer sets cover as much as 95% of the comammox amoA clade A and 92% of the clade B sequences in a reference database containing 326 comammox amoA genes with sequence information at the primer binding sites. Application of the primers to 13 samples from engineered systems (a groundwater well, drinking water treatment and wastewater treatment plants) and other habitats (rice paddy and forest soils, rice rhizosphere, brackish lake sediment and freshwater biofilm) detected comammox Nitrospira in all samples and revealed a considerable diversity of comammox in most habitats. Excellent primer specificity for comammox amoA was achieved by avoiding the use of highly degenerate primer preparations and by using equimolar mixtures of oligonucleotides that match existing comammox amoA genes. Quantitative PCR with these equimolar primer mixtures was highly sensitive and specific, and enabled the efficient quantification of clade A and clade B comammox amoA gene copy numbers in environmental samples. The measured relative abundances of comammox Nitrospira, compared to canonical ammonia oxidizers, were highly variable across environments. The new comammox amoA-targeted primers will enable more encompassing studies of nitrifying microorganisms in diverse ecosystems.
]]></description>
<dc:creator>Pjevac, P.</dc:creator>
<dc:creator>Schauberger, C.</dc:creator>
<dc:creator>Poghosyan, L.</dc:creator>
<dc:creator>Herbold, C. W.</dc:creator>
<dc:creator>van Kessel, M. A.</dc:creator>
<dc:creator>Daebeler, A.</dc:creator>
<dc:creator>Steinberger, M.</dc:creator>
<dc:creator>Jetten, M. S.</dc:creator>
<dc:creator>Lucker, S.</dc:creator>
<dc:creator>Wagner, M.</dc:creator>
<dc:creator>Daims, H.</dc:creator>
<dc:date>2016-12-27</dc:date>
<dc:identifier>doi:10.1101/096891</dc:identifier>
<dc:title><![CDATA[AmoA-targeted polymerase chain reaction primers for the specific detection and quantification of comammox Nitrospira in the environment]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2016-12-27</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/235028v1?rss=1">
<title>
<![CDATA[
Cultivation and genomic analysis of Candidatus Nitrosocaldus islandicus, a novel obligately thermophilic ammonia-oxidizing Thaumarchaeon 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/235028v1?rss=1"
</link>
<description><![CDATA[
Ammonia-oxidizing archaea (AOA) within the phylum Thaumarchaea are the only known aerobic ammonia oxidizers in geothermal environments. Although molecular data indicate the presence of phylogenetically diverse AOA from the Nitrosocaldus clade, group 1.1b and group 1.1a Thaumarchaea in terrestrial high-temperature habitats, only one enrichment culture of an AOA thriving above 50 {degrees}C has been reported and functionally analyzed. In this study, we physiologically and genomically characterized a novel Thaumarchaeon from the deep-branching Nitrosocaldaceae family of which we have obtained a high ([~]85 %) enrichment from biofilm of an Icelandic hot spring (73 {degrees}C). This AOA, which we provisionally refer to as "Candidatus Nitrosocaldus islandicus", is an obligately thermophilic, aerobic chemolithoautotrophic ammonia oxidizer, which stoichiometrically converts ammonia to nitrite at temperatures between 50 {degrees}C and 70 {degrees}C. Ca. N. islandicus encodes the expected repertoire of enzymes proposed to be required for archaeal ammonia oxidation, but unexpectedly lacks a nirK gene and also possesses no identifiable other enzyme for nitric oxide (NO) generation. Nevertheless, ammonia oxidation by this AOA appears to be NO-dependent as Ca. N. islandicus is, like all other tested AOA, inhibited by the addition of an NO scavenger. Furthermore, comparative genomics revealed that Ca. N. islandicus has the potential for aromatic amino acid fermentation as its genome encodes an indolepyruvate oxidoreductase (iorAB) as well as a type 3b hydrogenase, which are not present in any other sequenced AOA. A further surprising genomic feature of this thermophilic ammonia oxidizer is the absence of DNA polymerase D genes - one of the predominant replicative DNA polymerases in all other ammonia-oxidizing Thaumarchaea. Collectively, our findings suggest that metabolic versatility and DNA replication might differ substantially between obligately thermophilic and other AOA.
]]></description>
<dc:creator>Daebeler, A.</dc:creator>
<dc:creator>Herbold, C.</dc:creator>
<dc:creator>Vierheilig, J.</dc:creator>
<dc:creator>Sedlacek, C. J.</dc:creator>
<dc:creator>Pjevac, P.</dc:creator>
<dc:creator>Albersten, M.</dc:creator>
<dc:creator>Kirkegaard, R. H.</dc:creator>
<dc:creator>de la Torre, J. R.</dc:creator>
<dc:creator>Daims, H.</dc:creator>
<dc:creator>Wagner, M.</dc:creator>
<dc:date>2017-12-15</dc:date>
<dc:identifier>doi:10.1101/235028</dc:identifier>
<dc:title><![CDATA[Cultivation and genomic analysis of Candidatus Nitrosocaldus islandicus, a novel obligately thermophilic ammonia-oxidizing Thaumarchaeon]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2017-12-15</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/2020.10.16.342642v1?rss=1">
<title>
<![CDATA[
Evolutionary recent dual obligatory symbiosis among adelgids indicates a transition between fungus and insect associated lifestyles 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/2020.10.16.342642v1?rss=1"
</link>
<description><![CDATA[
Adelgids (Insecta: Hemiptera: Adelgidae) form a small group of insects but harbor a surprisingly diverse set of bacteriocyte-associated endosymbionts, which suggest multiple replacement and acquisition of symbionts over evolutionary time. Specific pairs of symbionts have been associated with adelgid lineages specialized on different secondary host conifers. Using a metagenomic approach, we investigated the symbiosis of the Adelges laricis/tardus species complex containing betaproteobacterial (  Candidatus Vallotia tarda) and gammaproteobacterial ( Candidatus Profftia tarda) symbionts. Genomic characteristics and metabolic pathway reconstructions revealed that Vallotia and Profftia are evolutionary young endosymbionts, which complement each others role in essential amino acid production. Phylogenomic analyses and a high level of genomic synteny indicate an origin of the betaproteobacterial symbiont from endosymbionts of Rhizopus fungi. This evolutionary transition was accompanied with substantial loss of functions related to transcription regulation, secondary metabolite production, bacterial defense mechanisms, host infection and manipulation. The transition from fungus to insect endosymbionts extends our current framework about evolutionary trajectories of host-associated microbes.
]]></description>
<dc:creator>Szabo, G.</dc:creator>
<dc:creator>Schulz, F.</dc:creator>
<dc:creator>Manzano-Marin, A.</dc:creator>
<dc:creator>Toenshoff, E. R.</dc:creator>
<dc:creator>Horn, M.</dc:creator>
<dc:date>2020-10-16</dc:date>
<dc:identifier>doi:10.1101/2020.10.16.342642</dc:identifier>
<dc:title><![CDATA[Evolutionary recent dual obligatory symbiosis among adelgids indicates a transition between fungus and insect associated lifestyles]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2020-10-16</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/2020.10.11.335026v1?rss=1">
<title>
<![CDATA[
Acquisition of a type 3 secretion signal in an housekeeping enzyme shaped glycogen metabolism in Chlamydia 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/2020.10.11.335026v1?rss=1"
</link>
<description><![CDATA[
The obligate intracellular bacteria Chlamydia trachomatis store glycogen in the lumen of the vacuoles in which they grow. Glycogen catabolism generates glucose-1-phosphate (Glc1P), while the bacteria are capable of taking up only glucose-6-phosphate (Glc6P). We tested whether the conversion of Glc1P into Glc6P could be catalyzed by a phosphoglucomutase (PGM) of host or bacterial origin. We found no evidence for the presence of the host enzyme in the vacuole. In C. trachomatis, two proteins are potential PGMs. By reconstituting the reaction, and by complementing PGM deficient fibroblasts, we demonstrated that only CT295 displayed robust PGM activity. Furthermore, we showed that glycogen accumulation by a subset of Chlamydia species correlated with the presence of a type three secretion (T3S) signal in their PGM. In conclusion, we established that the conversion of Glc1P into Glc6P was accomplished by a bacterial PGM, through the acquisition of a T3S signal in a "housekeeping" gene.
]]></description>
<dc:creator>Triboulet, S.</dc:creator>
<dc:creator>N'Gadjaga, M. D.</dc:creator>
<dc:creator>Niragire, B.</dc:creator>
<dc:creator>Köstlbacher, S.</dc:creator>
<dc:creator>Horn, M.</dc:creator>
<dc:creator>Subtil, A.</dc:creator>
<dc:date>2020-10-12</dc:date>
<dc:identifier>doi:10.1101/2020.10.11.335026</dc:identifier>
<dc:title><![CDATA[Acquisition of a type 3 secretion signal in an housekeeping enzyme shaped glycogen metabolism in Chlamydia]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2020-10-12</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/059816v1?rss=1">
<title>
<![CDATA[
Happens in the best of subfamilies: Replacement and internalisation of co-obligate Serratia endosymbionts in Lachninae aphids 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/059816v1?rss=1"
</link>
<description><![CDATA[
Virtually all aphids maintain an obligate mutualistic symbiosis with bacteria from the Buchnera genus, which produce essential nutrients for their aphid hosts. Most aphids from the Lachninae subfamily have been consistently found to house additional endosymbionts, mainly Serratia symbiotica. This apparent dependence on secondary endosymbionts was proposed to have been triggered by the loss of the riboflavin biosynthetic capability by Buchnera in the Lachninae last common ancestor. However, an integral large-scale analysis of secondary endosymbionts in the Lachninae is still missing, hampering the interpretation of the evolutionary and genomic analyses of these endosymbionts. Here, we analysed the endosymbionts of selected representatives from seven different Lachninae genera and nineteen species, spanning four tribes, both by FISH (exploring the symbionts morphology and tissue tropism) and 16S rRNA gene sequencing. We demonstrate that all analysed aphids possess dual symbiotic systems, and while most harbour S. symbiotica, some have undergone symbiont replacement by other phylogenetically-distinct bacterial taxa. We found that these secondary associates display contrasting cell shapes and tissue tropism, and some appear to be lineage-specific. a scenario for symbiont establishment in the Lachninae, followed by changes in the symbionts tissue tropism and symbiont replacement events, thereby highlighting the extraordinary versatility of host-symbiont interactions.nnOriginality-Significance StatementA key question in evolutionary biology is that of how mutualism evolves. One way to approach this problem is to investigate recently-established mutualistic associations, particularly by comparing various symbiotic systems in closely related hosts. Here, we present a most comprehensive study to investigate co-obligate symbioses in aphids, focusing in the Lachninae subfamily. While most aphids keep an obligate vertically-transmitted association with intracellular Buchnera bacteria, some, such as members of the Lachninae subfamily, host an additional putative co-obligate symbiont. Thus, the Lachninae dual symbiotic systems offer a unique opportunity to understand the evolutionary dynamics of host-symbiont associations, in particularly how secondary symbionts become obligate and eventually may be replaced. Through genome sequencing of three aphid species belonging to distantly related tribes within the subfamily, we have previously corroborated that they have indeed established co-obligate mutualistic associations with the S. symbiotica secondary endosymbiotic bacterium. This was putatively facilitated by an ancient pseudogenisation of the riboflavin biosynthetic pathway in Buchnera, rendering it unable to provide the essential vitamin to the host. However, not all Lachninae members harbour S. symbiotica, some species being associated to at least four different bacterial taxa. To correctly interpret the genomic data and to understand the evolutionary dynamics of these symbiotic associations, a wide-range analysis of both the phylogenetic relations as well as of the secondary symbionts localisation within the bacteriome is needed. To tackle this, we have combined phylogenetic analyses of the symbionts 16S rRNA gene sequences and FISH microscopy, to understand the symbionts identity as well as the morphological characteristics and tissue tropism. The phylogenetic affinities and patterns of co-divergence of the symbionts, in combination with previously published genomic data, have enabled us to build an evolutionary scenario for the establishment, changes in tissue tropism such as "stable" internalisation into bacteriocytes, and replacements of the putative "ancient" secondary endosymbiont from the Lachninae last common ancestor. Also, we were able to determine through phylogenetic analyses that some putative co-obligate endosymbionts may have evolved from once facultative ones. The evolutionary framework presented here reveals a dynamic pattern for the more recent evolutionary history of these symbioses, including replacement and novel acquisition of phylogenetically different co-obligate symbionts. This study opens new research avenues on this symbiont-diverse subfamily, providing insight into how mutualism in endosymbiotic associations can evolve, and the role these bacteria have played in the species adaptation and even in the speciation process.
]]></description>
<dc:creator>Alejandro Manzano-Marín</dc:creator>
<dc:creator>Gitta Szabó</dc:creator>
<dc:creator>Jean-Christophe Simon</dc:creator>
<dc:creator>Matthias Horn</dc:creator>
<dc:creator>Amparo Latorre</dc:creator>
<dc:creator></dc:creator>
<dc:date>2016-06-19</dc:date>
<dc:identifier>doi:10.1101/059816</dc:identifier>
<dc:title><![CDATA[Happens in the best of subfamilies: Replacement and internalisation of co-obligate Serratia endosymbionts in Lachninae aphids]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2016-06-19</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/2020.12.11.421487v1?rss=1">
<title>
<![CDATA[
The hidden pangenome: comparative genomics reveals pervasive diversity in symbiotic and free-living sulfur-oxidizing bacteria 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/2020.12.11.421487v1?rss=1"
</link>
<description><![CDATA[
Sulfur-oxidizing Thioglobaceae, often referred to as SUP05 and Arctic96BD clades, are widespread and common to hydrothermal vents and oxygen minimum zones. They impact global biogeochemical cycles and exhibit a variety of host-associated and free-living lifestyles. The evolutionary driving forces that led to the versatility, adoption of multiple lifestyles and global success of this family are largely unknown. Here, we perform an in-depth comparative genomic analysis using all available and newly generated Thioglobaceae genomes. Gene content variation was common, throughout taxonomic ranks and lifestyles. We uncovered a pool of variable genes within most Thioglobaceae populations in single environmental samples and we referred to this as the  hidden pangenome. The  hidden pangenome is often overlooked in comparative genomic studies and our results indicate a much higher intra-specific diversity within environmental bacterial populations than previously thought. Our results show that core-community functions are different from species core genomes suggesting that core functions across populations are divided among the intra-specific members within a population. Defense mechanisms against foreign DNA and phages were enriched in symbiotic lineages, indicating an increased exchange of genetic material in symbioses. Our study suggests that genomic plasticity and frequent exchange of genetic material drives the global success of this family by increasing its evolvability in a heterogeneous environment.
]]></description>
<dc:creator>Ansorge, R.</dc:creator>
<dc:creator>Romano, S.</dc:creator>
<dc:creator>Sayavedra, L.</dc:creator>
<dc:creator>Rubin-Blum, M.</dc:creator>
<dc:creator>Gruber-Vodicka, H. R.</dc:creator>
<dc:creator>Scilipoti, S.</dc:creator>
<dc:creator>Molari, M.</dc:creator>
<dc:creator>Dubilier, N.</dc:creator>
<dc:creator>Petersen, J.</dc:creator>
<dc:date>2020-12-11</dc:date>
<dc:identifier>doi:10.1101/2020.12.11.421487</dc:identifier>
<dc:title><![CDATA[The hidden pangenome: comparative genomics reveals pervasive diversity in symbiotic and free-living sulfur-oxidizing bacteria]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2020-12-11</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/2020.03.17.994798v1?rss=1">
<title>
<![CDATA[
Anaerobic sulfur oxidation underlies adaptation of a chemosynthetic symbiont to oxic-anoxic interfaces 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/2020.03.17.994798v1?rss=1"
</link>
<description><![CDATA[
Chemosynthetic symbioses occur worldwide in marine habitats, but comprehensive physiological studies of chemoautotrophic bacteria thriving on animals are scarce. Stilbonematinae are coated by monocultures of thiotrophic Gammaproteobacteria. As these nematodes migrate through the redox zone, their ectosymbionts experience varying oxygen concentrations. However, nothing is known about how these variations affect their physiology or metabolism. Here, by applying omics, Raman microspectroscopy and stable isotope labelling, we investigated the effect of oxygen on Candidatus Thiosymbion oneisti. Unexpectedly, sulfur oxidation genes were upregulated in anoxic relative to oxic conditions, but carbon fixation genes and incorporation of 13C-labeled bicarbonate were not. Instead, several genes involved in carbon fixation were upregulated in oxic conditions, together with genes involved in organic carbon assimilation, polyhydroxyalkanoate (PHA) biosynthesis, nitrogen fixation and urea utilization. Furthermore, in the presence of oxygen, stress-related genes were upregulated together with vitamin biosynthesis genes likely necessary to withstand its deleterious effects, and the symbiont appeared to proliferate less. Based on its physiological response to oxygen, we propose that Ca. T. oneisti may exploit anaerobic sulfur oxidation coupled to denitrification to proliferate in anoxic sand. However, the ectosymbiont would still profit from the oxygen available in superficial sand, as the energy-efficient aerobic respiration would facilitate carbon and nitrogen assimilation by the ectosymbiont.

IMPORTANCEChemoautotrophic endosymbionts are famous for exploiting sulfur oxidization to feed marine organisms with fixed carbon. However, the physiology of thiotrophic bacteria thriving on the surface of animals (ectosymbionts) is less understood. One long standing hypothesis posits that attachment to animals that migrate between reduced and oxic environments would boost sulfur oxidation, as the ectosymbionts would alternatively access sulfide and oxygen, the most favorable electron acceptor. Here, we investigated the effect of oxygen on the physiology of Candidatus Thiosymbion oneisti, a Gammaproteobacterium which lives attached to marine nematodes inhabiting shallow water sand. Surprisingly, sulfur oxidation genes were upregulated in anoxic relative to oxic conditions. Furthermore, under anoxia, the ectosymbiont appeared to be less stressed and to proliferate more. We propose that animal-mediated access to oxygen, rather than enhancing sulfur oxidation, would facilitate assimilation of carbon and nitrogen by the ectosymbiont.
]]></description>
<dc:creator>Bulgheresi, S.</dc:creator>
<dc:creator>Paredes, G. F.</dc:creator>
<dc:creator>Viehboek, T.</dc:creator>
<dc:creator>Lee, R.</dc:creator>
<dc:creator>Palatinszky, M.</dc:creator>
<dc:creator>Mausz, M.</dc:creator>
<dc:creator>Reipert, S.</dc:creator>
<dc:creator>Schintlmeister, A.</dc:creator>
<dc:creator>Volland, J.-M.</dc:creator>
<dc:creator>Hirschfeld, C.</dc:creator>
<dc:creator>Wagner, M.</dc:creator>
<dc:creator>Berry, D.</dc:creator>
<dc:creator>Markert, S.</dc:creator>
<dc:creator>Koenig, L.</dc:creator>
<dc:date>2020-03-18</dc:date>
<dc:identifier>doi:10.1101/2020.03.17.994798</dc:identifier>
<dc:title><![CDATA[Anaerobic sulfur oxidation underlies adaptation of a chemosynthetic symbiont to oxic-anoxic interfaces]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2020-03-18</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/531459v1?rss=1">
<title>
<![CDATA[
Diversity matters: Deep-sea mussels harbor multiple symbiont strains 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/531459v1?rss=1"
</link>
<description><![CDATA[
Genetic diversity of closely-related free-living microbes is widespread and underpins ecosystem functioning, but most evolutionary theories predict that it destabilizes intimate mutualisms. Indeed, symbiont strain diversity has long assumed to be restricted in intracellular bacteria associated with animals. Here, we sequenced the metagenomes and metatranscriptomes of 18 Bathymodiolus mussel individuals from four species, covering their known distribution range at deep-sea hydrothermal vents in the Atlantic. We show that as many as 16 strains of intracellular, sulfur-oxidizing symbionts coexist in individual Bathymodiolus mussels. Co-occurring symbiont strains differed extensively in key metabolic functions, such as the use of energy and nutrient sources, electron acceptors and viral defense mechanisms. Most strain-specific genes were expressed, highlighting their adaptive potential. We show that fine-scale diversity is pervasive in Bathymodiolus symbionts, and hypothesize that it may be widespread in low-cost symbioses where the environment, not the host, feeds the symbionts.
]]></description>
<dc:creator>Ansorge, R.</dc:creator>
<dc:creator>Romano, S.</dc:creator>
<dc:creator>Sayavedra, L.</dc:creator>
<dc:creator>Kupczok, A.</dc:creator>
<dc:creator>Tegetmeyer, H. E.</dc:creator>
<dc:creator>Dubilier, N.</dc:creator>
<dc:creator>Petersen, J.</dc:creator>
<dc:date>2019-01-26</dc:date>
<dc:identifier>doi:10.1101/531459</dc:identifier>
<dc:title><![CDATA[Diversity matters: Deep-sea mussels harbor multiple symbiont strains]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2019-01-26</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/128660v1?rss=1">
<title>
<![CDATA[
Vitamin and amino acid auxotrophy in anaerobic consortia operating under methanogenic condition 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/128660v1?rss=1"
</link>
<description><![CDATA[
Syntrophy among Archaea and Bacteria facilitates the anaerobic degradation of organic compounds to CH4 and CO2. Particularly during aliphatic and aromatic hydrocarbon mineralization, as in crude oil reservoirs and petroleum-contaminated sediments, metabolic interactions between obligate mutualistic microbial partners are of central importance1. Using micro-manipulation combined with shotgun metagenomic approaches, we disentangled the genomes of complex consortia inside a short chain alkane-degrading cultures operating under methanogenic conditions. Metabolic reconstruction revealed that only a small fraction of genes in the metagenome-assembled genomes of this study, encode the capacity for fermentation of alkanes facilitated by energy conservation linked to H2 metabolism. Instead, inferred lifestyles based on scavenging anabolic products and intermediate fermentation products derived from detrital biomass was a common feature in the consortia. Additionally, inferred auxotrophy for vitamins and amino acids suggests that the hydrocarbon-degrading microbial assemblages are structured and maintained by multiple interactions beyond the canonical H2-producing and syntrophic alkane degrader-methanogen partnership2. Our study uncovers the complexity of  interactomes within microbial consortia mediating hydrocarbon transformation under anaerobic conditions.
]]></description>
<dc:creator>Hubalek, V.</dc:creator>
<dc:creator>Buck, M.</dc:creator>
<dc:creator>Tan, B.</dc:creator>
<dc:creator>Foght, J.</dc:creator>
<dc:creator>Wendeberg, A.</dc:creator>
<dc:creator>Berry, D.</dc:creator>
<dc:creator>Bertilsson, S.</dc:creator>
<dc:creator>Eiler, A.</dc:creator>
<dc:date>2017-04-19</dc:date>
<dc:identifier>doi:10.1101/128660</dc:identifier>
<dc:title><![CDATA[Vitamin and amino acid auxotrophy in anaerobic consortia operating under methanogenic condition]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2017-04-19</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/2022.03.11.483957v1?rss=1">
<title>
<![CDATA[
Ecology and evolution of chlamydial symbionts of arthropods 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/2022.03.11.483957v1?rss=1"
</link>
<description><![CDATA[
The phylum Chlamydiae consists of obligate intracellular bacteria including major human pathogens and diverse environmental representatives. Here we investigated the Rhabdochlamydiaceae, which is predicted to be the largest and most diverse chlamydial family, with the few described members known to infect arthropod hosts. Using published 16S rRNA gene sequence data we identified at least 388 genus-level lineages containing about 14 051 putative species within this family. We show that rhabdochlamydiae are mainly found in freshwater and soil environments, suggesting the existence of diverse, yet unknown hosts. Next, we used a comprehensive genome dataset including metagenome assembled genomes classified as members of the family Rhabdochlamydiaceae, and we added novel complete genome sequences of Rhabdochlamydia porcellionis infecting the woodlouse Porcellio scaber, and of  Candidatus R. oedothoracis associated with the linyphiid dwarf spider Oedothorax gibbosus. Comparative analysis of basic genome features and gene content with reference genomes of well-studied chlamydial families with known host ranges, namely Parachlamydiaceae (protist hosts) and Chlamydiaceae (human and other vertebrate hosts) suggested distinct niches for members of the Rhabdochlamydiaceae. We propose that members of the family represent intermediate stages of adaptation of chlamydiae from protists to vertebrate hosts. Within the genus Rhabdochlamydia, pronounced genome size reduction could be observed (1.49-1.93 Mb). The abundance and genomic distribution of transposases suggests transposable element expansion and subsequent gene inactivation as a mechanism of genome streamlining during adaptation to new hosts. This type of genome reduction has never been described before for any member of the phylum Chlamydiae. This study provides new insights into the molecular ecology, genomic diversity, and evolution of representatives of one of the most divergent chlamydial families.
]]></description>
<dc:creator>Halter, T.</dc:creator>
<dc:creator>Koestlbacher, S.</dc:creator>
<dc:creator>Collingro, A.</dc:creator>
<dc:creator>Sixt, B. S.</dc:creator>
<dc:creator>Toenshoff, E. R.</dc:creator>
<dc:creator>Hendrickx, F.</dc:creator>
<dc:creator>Kostanjsek, R.</dc:creator>
<dc:creator>Horn, M.</dc:creator>
<dc:date>2022-03-13</dc:date>
<dc:identifier>doi:10.1101/2022.03.11.483957</dc:identifier>
<dc:title><![CDATA[Ecology and evolution of chlamydial symbionts of arthropods]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2022-03-13</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/2022.05.31.494226v1?rss=1">
<title>
<![CDATA[
One to host them all: genomics of the diverse bacterial endosymbionts of the spider Oedothorax gibbosus 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/2022.05.31.494226v1?rss=1"
</link>
<description><![CDATA[
Bacterial endosymbionts of the groups Wolbachia, Cardinium and Rickettsiaceae are well-known for their diverse effects on their arthropod hosts, ranging from mutualistic relationships to reproductive phenotypes. Here, we analyzed a unique system in which the dwarf spider Oedothorax gibbosus is co-infected with up to five different endosymbionts affiliated with Wolbachia,  Candidatus Tisiphia (formerly Torix group Rickettsia), Cardinium, and Rhabdochlamydia. Using short-read genome sequencing data, we show that the endosymbionts are heterogeneously distributed among O. gibbosus populations and are frequently found co-infecting spider individuals. To study this intricate host-endosymbiont system on a genome resolved level, we used long-read sequencing to reconstruct closed genomes of the Wolbachia,  Ca. Tisiphia and Cardinium endosymbionts. We provide insights in the ecology and evolution of the endosymbionts and shed light on the interactions with their spider host. We detected high quantities of transposable elements in all endosymbiont genomes and provide evidence that ancestors of the Cardinium,  Ca. Tisiphia and Wolbachia endosymbionts have co-infected the same hosts in the past. Our findings contribute to broadening our knowledge about endosymbionts infecting one of the largest animal phyla on earth and show the usefulness of transposable elements as an evolutionary "contact-tracing" tool.

Data summaryAll supporting data, code and protocols have been provided within the article or through supplementary data files. Seven supplementary figures and seven supplementary tables are available with the online version of this article. Sequencing data used in this study was generated and previously published by Hendrickx et al., 2021. Genome assemblies generated in this study have been deposited under the project PRJEB52003 at DDBJ/ENA/GenBank. The MAG of R. oedothoracis OV001 was deposited at DDBJ/ENA/GenBank under the sample SAMN28026840. The genome of  Candidatus Rhabdochlamydia oedothoracis W744x776 was previously published by Halter et al., 2022 and is available at DDBJ/ENA/GenBank (accession: CP075587-CP075588). The collection of genomes and proteomes, all files for phylogenetic analyses including gene alignments, concatenated alignments, and tree files, and original output files of the HGT and SNP predictions used in this study are available at zenodo (https://doi.org/10.5281/zenodo.6362846).
]]></description>
<dc:creator>Halter, T.</dc:creator>
<dc:creator>Köstlbacher, S.</dc:creator>
<dc:creator>Rattei, T.</dc:creator>
<dc:creator>Hendrickx, F.</dc:creator>
<dc:creator>Manzano-Marin, A.</dc:creator>
<dc:creator>Horn, M.</dc:creator>
<dc:date>2022-05-31</dc:date>
<dc:identifier>doi:10.1101/2022.05.31.494226</dc:identifier>
<dc:title><![CDATA[One to host them all: genomics of the diverse bacterial endosymbionts of the spider Oedothorax gibbosus]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2022-05-31</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/2023.06.27.546762v1?rss=1">
<title>
<![CDATA[
Global diversity and inferred ecophysiology of microorganisms with the potential for dissimilatory sulfate/sulfite reduction 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/2023.06.27.546762v1?rss=1"
</link>
<description><![CDATA[
Sulfate/sulfite-reducing microorganisms (SRM) are ubiquitous in nature, driving the global sulfur cycle. A hallmark of SRM is the dissimilatory sulfite reductase encoded by the paralogous genes dsrAB. Based on analysis of 950 mainly metagenome-derived dsrAB-encoding genomes, we redefine the global diversity of microorganisms with the potential for dissimilatory sulfate/sulfite reduction and uncover genetic repertoires that challenge earlier generalizations regarding their mode of energy metabolism. We show: (i) 19 out of 23 bacterial and 2 out of 4 archaeal phyla harbor uncharacterized SRM, (ii) four phyla including the Desulfobacterota harbor microorganisms with the genetic potential to switch between sulfate/sulfite reduction and sulfur oxidation, and (iii) the combination as well as presence/absence of different dsrAB-types, dsrL-types and dsrD provides guidance on the inferred direction of dissimilatory sulfur metabolism. We further provide an updated dsrAB database including >60% taxonomically resolved, uncultured family-level lineages and recommendations on existing dsrAB primers for environmental surveys. Our work summarizes insights into the inferred ecophysiology of newly discovered SRM, puts SRM diversity into context of the major recent changes in bacterial and archaeal taxonomy, and provides an up-to-date framework to study SRM in a global context.

One sentence summarySulfate/sulfite reducing microorganisms are shaping Earths interconnected sulfur and carbon cycles since the Archaean: this legacy unfolds in 27 archaeal and bacterial phyla encountered in diverse marine, terrestrial, and deep-subsurface environments.
]]></description>
<dc:creator>Diao, M.</dc:creator>
<dc:creator>Dyksma, S.</dc:creator>
<dc:creator>Koeksoy, E.</dc:creator>
<dc:creator>Ngugi, D. K.</dc:creator>
<dc:creator>Anantharaman, K.</dc:creator>
<dc:creator>Loy, A.</dc:creator>
<dc:creator>Pester, M.</dc:creator>
<dc:date>2023-06-27</dc:date>
<dc:identifier>doi:10.1101/2023.06.27.546762</dc:identifier>
<dc:title><![CDATA[Global diversity and inferred ecophysiology of microorganisms with the potential for dissimilatory sulfate/sulfite reduction]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2023-06-27</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/2022.10.05.510937v1?rss=1">
<title>
<![CDATA[
A novel taurine-respiring murine gut bacterium contributes to colonization resistance against enteropathogens 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/2022.10.05.510937v1?rss=1"
</link>
<description><![CDATA[
Taurine-respiring gut bacteria produce H2S with ambivalent impact on host health. We report the isolation and genomic-ecophysiological characterization of the first taurine-respiring mouse gut bacterium. Taurinivorans muris represents a new widespread species with protective capacity against pathogens and differs from the human gut sulfidogen Bilophila wadsworthia in its sulfur metabolism and host distribution. Despite alternative physiologies, taurine respiration was the main in vivo lifestyle of T. muris independent of mouse diet and genotype. In gnotobiotic mice, T. muris selectively enhanced the activity of a sulfur metabolism gene-encoding prophage and provided slightly increased colonization resistance against Salmonella Typhimurium, which showed reduced expression of galactonate catabolism genes. We identified T. muris as the dominant sulfidogen of a mouse microbiota that conferred H2S-mediated protection against Klebsiella pneumoniae in a previous study. Together, we revealed the realized physiological niche of a key murine gut sulfidogen and its impact on pathogen and phage gene expression.

One sentence summaryOur work identified and characterized a new core member of the murine gut microbiota, revealed sulfidogenic taurine respiration as its predominant in vivo lifestyle, and emphasizes its protective function in pathogen colonization.
]]></description>
<dc:creator>Ye, H.</dc:creator>
<dc:creator>Borusak, S.</dc:creator>
<dc:creator>Eberl, C.</dc:creator>
<dc:creator>Hanson, B. T.</dc:creator>
<dc:creator>Zwirzitz, B.</dc:creator>
<dc:creator>Herbold, C.</dc:creator>
<dc:creator>Pjevac, P.</dc:creator>
<dc:creator>Hausmann, B.</dc:creator>
<dc:creator>Stecher, B.</dc:creator>
<dc:creator>Schleheck, D.</dc:creator>
<dc:creator>Loy, A.</dc:creator>
<dc:date>2022-10-05</dc:date>
<dc:identifier>doi:10.1101/2022.10.05.510937</dc:identifier>
<dc:title><![CDATA[A novel taurine-respiring murine gut bacterium contributes to colonization resistance against enteropathogens]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2022-10-05</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/2025.01.22.634256v1?rss=1">
<title>
<![CDATA[
Sulfoquinovose is differently degraded by the mouse and human gut microbiota and not metabolized by the host 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/2025.01.22.634256v1?rss=1"
</link>
<description><![CDATA[
BackgroundSulfoquinovose (SQ) is a green-diet-derived sulfonated glucose and a selective substrate for few human gut bacteria. Complete anaerobic SQ degradation via interspecies metabolite transfer to sulfonate-respiring bacteria produces hydrogen sulfide, which has dose- and context-dependent health effects. Here, we studied potential SQ degradation by the mammalian host and the impact of SQ supplementation on human and murine gut microbiota diversity and metabolism.

Results13CO2 breath tests with germ-free C57BL/6 mice gavaged with 13C-SQ were negative. Also, SQ was not degraded by human intestinal cells in vitro, indicating that SQ is not directly metabolized by mice and humans. Addition of increasing SQ concentrations to human fecal microcosms revealed dose-dependent responses of the microbiota and corroborated the relevance of Agathobacter rectalis and Bilophila wadsworthia in cooperative degradation of SQ to hydrogen sulfide via interspecies transfer of 2,3-dihydroxy-1-propanesulfonate (DHPS). Similar to the human gut microbiome, the genetic capacity for SQ or DHPS degradation is sparsely distributed among bacterial species in the mouse gut. Escherichia coli and Enterocloster clostridioformis were identified as primary SQ degraders in the mouse gut. SQ and DHPS supplementation experiments with conventional laboratory mice and their intestinal contents showed that SQ was incompletely catabolized to DHPS. Although some E. clostridioformis genomes encode an extended sulfoglycolytic pathway for both SQ and DHPS fermentation, SQ was only degraded to DHPS by a mouse-derived E. clostridioformis strain.

ConclusionsOur findings suggest that SQ is solely a nutrient for the gut microbiota and not for mice and humans, emphasizing its potential as a prebiotic. SQ degradation by the microbiota of conventional laboratory mice differs from the human gut microbiota by absence of DHPS degradation activity. Hence, the microbiota of conventional laboratory mice does not fully represent the SQ metabolism in humans, indicating the need for alternative model systems to assess the impact of SQ on human health. This study advances our understanding of how individual dietary compounds shape the microbial community structure and metabolism in the gut and thereby potentially influence host health.
]]></description>
<dc:creator>Krasenbrink, J.</dc:creator>
<dc:creator>Hanson, B. T.</dc:creator>
<dc:creator>Weiss, A. S.</dc:creator>
<dc:creator>Borusak, S.</dc:creator>
<dc:creator>Tanabe, T. S.</dc:creator>
<dc:creator>Lang, M.</dc:creator>
<dc:creator>Aichinger, G.</dc:creator>
<dc:creator>Hausmann, B.</dc:creator>
<dc:creator>Berry, D.</dc:creator>
<dc:creator>Richter, A.</dc:creator>
<dc:creator>Marko, D.</dc:creator>
<dc:creator>Mussmann, M.</dc:creator>
<dc:creator>Schleheck, D.</dc:creator>
<dc:creator>Stecher, B.</dc:creator>
<dc:creator>Loy, A.</dc:creator>
<dc:date>2025-01-22</dc:date>
<dc:identifier>doi:10.1101/2025.01.22.634256</dc:identifier>
<dc:title><![CDATA[Sulfoquinovose is differently degraded by the mouse and human gut microbiota and not metabolized by the host]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2025-01-22</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/2025.01.10.632322v1?rss=1">
<title>
<![CDATA[
Host-specific microbiome and genomic signatures in Bifidobacterium reveal co-evolutionary and functional adaptations across diverse animal hosts 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/2025.01.10.632322v1?rss=1"
</link>
<description><![CDATA[
Animal hosts harbour divergent microbiota, including various Bifidobacterium species and strains, yet their evolutionary relationships, and functional adaptions remain understudied. By integrating taxonomic, genomic and predicted functional annotations, we uncover how Bifidobacterium adapts to host-specific environments, shaped by vertical transmission, dietary influences, and host phylogeny. Our findings reveal that host phylogeny is a major determinant of gut microbiota composition. Distinct microbial networks in mammalian and avian hosts reflect evolutionary adaptations to dietary niches, such as carnivory, and ecological pressures. At a strain-resolved level, we identify strong co-phylogenetic associations between Bifidobacterium strains and their hosts, driven by vertical transmission and dietary selection, underscoring the intricate co-evolutionary dynamics between these microbes and their hosts. Functional analyses highlight striking host-specific metabolic adaptations in Bifidobacterium, particularly in carbohydrate metabolism and oxidative stress responses. In mammals, we observe an enrichment of glycoside hydrolases (GH) tailored to complex carbohydrate-rich diets, including multi-domain GH13_28 -amylases featuring diverse carbohydrate-binding modules (CBM25, CBM26, and the novel CBM74). These adaptations emphasise the ecological flexibility of Bifidobacterium in breaking down -linked glucose polysaccharides, such as resistant starch. Together, our study provides new insights into the evolutionary trajectories and ecological plasticity of Bifidobacterium, revealing how host phylogeny and dietary ecology drive microbial diversity and function. These findings deepen our understanding of host-microbe co-evolution and the critical role of microbiota in shaping animal health and adaptation.
]]></description>
<dc:creator>Kujawska, M.</dc:creator>
<dc:creator>Seki, D.</dc:creator>
<dc:creator>Chalklen, L.</dc:creator>
<dc:creator>Malsom, J.</dc:creator>
<dc:creator>Goatcher, S.</dc:creator>
<dc:creator>Christoforou, I.</dc:creator>
<dc:creator>Mitra, S.</dc:creator>
<dc:creator>Crouch, L.</dc:creator>
<dc:creator>Hall, L. J.</dc:creator>
<dc:date>2025-01-11</dc:date>
<dc:identifier>doi:10.1101/2025.01.10.632322</dc:identifier>
<dc:title><![CDATA[Host-specific microbiome and genomic signatures in Bifidobacterium reveal co-evolutionary and functional adaptations across diverse animal hosts]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2025-01-11</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/2024.12.20.629319v1?rss=1">
<title>
<![CDATA[
Pervasive phosphorylation by phage T7 kinase disarms bacterial defenses 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/2024.12.20.629319v1?rss=1"
</link>
<description><![CDATA[
Bacteria and bacteriophages are in a constant arms race to develop bacterial defense and phage counter-defense systems. Currently known phage counter-defense systems are specific to (the activity of) the targeted bacterial defense system. Here, we uncover a mechanism by which the T7 bacteriophage broadly counteracts bacterial defenses using protein phosphorylation. We show that the T7 protein kinase (T7K), which was believed to specifically redirect the function of a few host proteins, is in fact a hyper-promiscuous, dual-specificity kinase enacting a massive wave of phosphorylation on virtually all host and phage proteins during infection. The scale of phosphorylation vastly exceeds the number of previously known phosphorylation events in E. coli, has no sequence motif specificity, and results in a higher proteome-wide phosphorylation density than that of mammalian cells which encode [~] 500 kinases. Stoichiometry analysis of phosphorylation sites revealed a strong bias of T7K activity towards nucleic acid-binding substrates, which we show is mediated by its C-terminal DNA-binding domain. This specificity for highly stoichiometric phosphorylation of nucleic acid-binding proteins enables the deactivation of DNA-targeting or - containing bacterial defense systems. We provide mechanistic insight into how T7K weakens two such defense systems, Retron-Eco9 and DarTG1, through specific phosphorylation events, with single phosphomimetic mutations in key sites of the toxins abolishing defense. Finally, by screening a large collection of E. coli strains, we provide evidence of broad counter-defense capacities for T7K in nature, as strains counteracted contain diverse bacterial defense systems.
]]></description>
<dc:creator>Bartolec, T.</dc:creator>
<dc:creator>Mitosch, K.</dc:creator>
<dc:creator>Potel, C.</dc:creator>
<dc:creator>Corona, F.</dc:creator>
<dc:creator>Yang, A. L. J.</dc:creator>
<dc:creator>Burtscher, M. L.</dc:creator>
<dc:creator>Koumoutsi, A.</dc:creator>
<dc:creator>Becher, I.</dc:creator>
<dc:creator>Bobonis, J.</dc:creator>
<dc:creator>Karcher, N.</dc:creator>
<dc:creator>Galardini, M.</dc:creator>
<dc:creator>Typas, A.</dc:creator>
<dc:creator>Savitski, M. M.</dc:creator>
<dc:date>2024-12-20</dc:date>
<dc:identifier>doi:10.1101/2024.12.20.629319</dc:identifier>
<dc:title><![CDATA[Pervasive phosphorylation by phage T7 kinase disarms bacterial defenses]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2024-12-20</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/2024.12.16.628686v1?rss=1">
<title>
<![CDATA[
The methane-cycling microbiome in intact and degraded permafrost soils of the pan-Arctic 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/2024.12.16.628686v1?rss=1"
</link>
<description><![CDATA[
The methane-cycling microbiomes in Arctic permafrost-affected soils play crucial roles in the production and consumption of this important greenhouse gas. However, little is known about the distributions of Arctic methanogens and methanotrophs across the regional scale and along the vertical soil profile, as well as their responses to the widespread permafrost thaw. Using a unique sample set from nine different locations across the pan-Arctic, we identified methanogen and methanotroph phylotypes in 729 datasets of 16S rRNA gene amplicons.

In 621 samples of intact permafrost soils across the pan-Arctic, only 22 methanogen and 26 methanotroph phylotypes were identified. Relative abundances of both functional groups varied significantly between sites and soil horizons. Only four methanogen phylotypes were detected at all locations, with the hydrogenotrophic Methanobacterium lacus dominating. Remarkably, the permafrost soil methane filter was almost exclusively comprised of a few phylotypes closely related to the obligate methanotrophic species Methylobacter tundripaludum.

In degraded permafrost sites in Alaska, M. tundripaludum also dominated the methanotroph microbiome in the wet site. However, in dry, water-drained former permafrost site, Methylocapsa phylotypes, closely related with the atmospheric methane oxidizing bacteria, were exclusively found and dominant, indicating a massive restructuring of the methanotroph guild that consequently resulted in functional changes from a soil methane filter to an atmospheric methane sink.

This study provides first insights into the identity and intricate spatial distribution of methanotrophs and methanogens in permafrost soils at a pan-Arctic scale and their responses to different water status after permafrost degradation. These findings point towards a few key microbes particularly relevant for future studies on Arctic CH4 dynamics in a warming climate and that under future dry conditions more atmospheric CH4 uptake in Arctic upland soils might happen.
]]></description>
<dc:creator>Wang, H.</dc:creator>
<dc:creator>Lindemann, E.</dc:creator>
<dc:creator>Liebmann, P.</dc:creator>
<dc:creator>Varsadiya, M.</dc:creator>
<dc:creator>Svenning, M. M.</dc:creator>
<dc:creator>Waqas, M.</dc:creator>
<dc:creator>Petters, S.</dc:creator>
<dc:creator>Richter, A.</dc:creator>
<dc:creator>Guggenberger, G.</dc:creator>
<dc:creator>Barta, J.</dc:creator>
<dc:creator>Urich, T.</dc:creator>
<dc:date>2024-12-16</dc:date>
<dc:identifier>doi:10.1101/2024.12.16.628686</dc:identifier>
<dc:title><![CDATA[The methane-cycling microbiome in intact and degraded permafrost soils of the pan-Arctic]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2024-12-16</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/2024.12.03.626624v1?rss=1">
<title>
<![CDATA[
Soil microbes prefer organic acids over sugars in simulated root exudation 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/2024.12.03.626624v1?rss=1"
</link>
<description><![CDATA[
Sugars and organic acids, primary components in plant root exudates, are thought to enhance microbial decomposition of organic matter in the rhizosphere. However, their specific impacts on microbial activity and nutrient mobilisation remain poorly understood. Here, we simulated passive root exudation to investigate the distinct effects of sugars and organic acids on microbial metabolism in the rhizosphere. We released 13C- labelled sugars and/or organic acids via reverse microdialysis into intact meadow and forest soils over 6-hours. We measured substrate-induced microbial respiration, soil organic matter mineralization, metabolite concentrations, and substrate incorporation into lipid-derived fatty acids. Our results reveal a pronounced microbial preference for organic acids over sugars, with organic acids being removed faster from the exudation spot and preferentially respired by microbes. Unlike sugars, organic acids increased concentrations of microbial metabolic byproducts and cations (K, Ca, Mg) near the exudation spot. Our results challenge the prevailing assumption that sugars are the most readily available and rapidly consumed substrates for soil microbes. Microbial preference for organic acids indicates a trade-off between rapid biomass growth and ATP yield. Our findings underscore the significant role of exudate composition in influencing microbial dynamics and nutrient availability, and emphasize the importance of biotic and abiotic feedback mechanisms in the rhizosphere in regulating root exudation.
]]></description>
<dc:creator>Wiesenbauer, J.</dc:creator>
<dc:creator>Gorka, S.</dc:creator>
<dc:creator>Jenab, K.</dc:creator>
<dc:creator>Schuster, R.</dc:creator>
<dc:creator>Kumar, N.</dc:creator>
<dc:creator>Rottensteiner, C.</dc:creator>
<dc:creator>Koenig, A.</dc:creator>
<dc:creator>Kraemer, S.</dc:creator>
<dc:creator>Inselsbacher, E.</dc:creator>
<dc:creator>Kaiser, C.</dc:creator>
<dc:date>2024-12-03</dc:date>
<dc:identifier>doi:10.1101/2024.12.03.626624</dc:identifier>
<dc:title><![CDATA[Soil microbes prefer organic acids over sugars in simulated root exudation]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2024-12-03</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/2024.12.02.626346v1?rss=1">
<title>
<![CDATA[
Soil bacterial neutral lipid fatty acids: Markers for carbon storage or necromass? 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/2024.12.02.626346v1?rss=1"
</link>
<description><![CDATA[
Carbon storage is a common strategy of soil microbes to cope with resource fluctuations. Fungi use neutral lipids (triacylglycerols, TAGs) for storage, which can be quantified via their derived fatty acids (NLFAs). NLFAs specific to bacteria can also be abundant in soils, but are rarely analysed as soil bacteria are assumed to not store TAGs. Instead, bacterial NLFAs are thought to derive from degraded phospholipids (diacylglycerols, DAGs), and thus indicate bacterial necromass, but this interpretation lacks evidence. In this perspective, we synthesise knowledge from the literature and our own experimental results on the origin of soil bacterial NLFAs. In sum, we provide evidence that bacterial NLFAs are predominantly derived from TAGs used for carbon storage: (1) Several pure culture studies provide evidence for TAG production in selected bacterial isolates. (2) Screening of genomes showed that wax ester synthase/diacylglycerol acyltransferases, which mediate the last step of TAG synthesis, are abundant in bacterial isolates from soil, suggesting a widespread genetic capability to produce TAGs. (3) We experimentally created conditions of excess labile carbon by adding isotopically labelled glucose to soil. Glucose-13C was rapidly allocated into bacterial NLFAs, with higher relative enrichment than phospholipid-derived fatty acids, indicating storage. (4) DAGs are not necessarily produced--and may only be intermediate compounds--during phospholipid degradation. We conclude that soil bacterial NLFAs are mainly derived from storage compounds, but a potential contribution from degraded phospholipids needs further validation. Isotopic labelling could resolve this, making NLFAs a valuable biomarker for microbial storage compounds in soil.

HighlightsO_LIBacterial NLFAs originate from triacylglycerols (TAGs) or degraded phospholipids
C_LIO_LINeutral lipids are not necessarily produced during phospholipid degradation
C_LIO_LISoil bacteria have the genetic potential to produce TAGs for storage
C_LIO_LIRapid transfer of excess glucose-13C into soil bacterial NLFAs suggests storage
C_LIO_LIBacterial NLFAs are markers for carbon storage rather than necromass
C_LI
]]></description>
<dc:creator>Gorka, S.</dc:creator>
<dc:creator>Canarini, A.</dc:creator>
<dc:creator>Schmidt, H.</dc:creator>
<dc:creator>Kaiser, C.</dc:creator>
<dc:date>2024-12-02</dc:date>
<dc:identifier>doi:10.1101/2024.12.02.626346</dc:identifier>
<dc:title><![CDATA[Soil bacterial neutral lipid fatty acids: Markers for carbon storage or necromass?]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2024-12-02</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/2024.11.28.625222v1?rss=1">
<title>
<![CDATA[
The adaptation of chlamydiae to facultative host multicellularity 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/2024.11.28.625222v1?rss=1"
</link>
<description><![CDATA[
The phylum Chlamydiota consists of obligate intracellular bacteria comprising the human pathogen Chlamydia trachomatis and a large variety of species infecting animals and protists. Despite their enormous diversity, a feature shared by all known chlamydiae is their biphasic developmental cycle, consisting of intra- and extracellular stages with substantial differences in morphology and physiology. A similarly remarkable shift occurs in the amoeba Dictyostelium discoideum and related dictyostelids in their so-called social life cycle, leading to the formation of spores through aggregation of vegetative trophozoites and the development of multicellular fruiting bodies. Although dictyostelids undergo symbioses with various bacteria, chlamydiae have only recently been found to be associated with this host. Here we report the isolation of a Dictyostelium giganteum strain naturally infected with a chlamydial symbiont, identified as a novel species, Reclusachlamydia socialis. The symbiont is retained in all stages of the hosts social life cycle and notably lacks an extracellular form. Combining fluorescence microscopy and quantitative PCR we showed that transmission is entirely dependent on cell-to-cell contact during the host aggregation stage. The absence of an extracellular stage is further supported by transmission electron microscopy and the lack of genes essential for chlamydial developmental cycle regulation and extracellular survival. This unprecedented variation of a highly conserved developmental feature that evolved more than a billion years ago illustrates the remarkable adaptability of chlamydiae. This study adds to our understanding of endosymbiosis in the face of facultative multicellularity.
]]></description>
<dc:creator>Helmlinger, L.</dc:creator>
<dc:creator>Arthofer, P.</dc:creator>
<dc:creator>Cyran, N.</dc:creator>
<dc:creator>Collingro, A.</dc:creator>
<dc:creator>Horn, M.</dc:creator>
<dc:date>2024-11-28</dc:date>
<dc:identifier>doi:10.1101/2024.11.28.625222</dc:identifier>
<dc:title><![CDATA[The adaptation of chlamydiae to facultative host multicellularity]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2024-11-28</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/2024.11.16.623942v1?rss=1">
<title>
<![CDATA[
Contribution of ammonia oxidizers to inorganic carbon fixation in the dark ocean 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/2024.11.16.623942v1?rss=1"
</link>
<description><![CDATA[
Ammonia-oxidizing archaea are the most abundant chemolithoautotrophs in the ocean, comprising up to 40% of microbial cells in deep waters, and are assumed to dominate dissolved inorganic carbon (DIC) fixation below the sunlit surface layer. Yet, the supply of reduced nitrogen from particulate organic matter flux from the surface is insufficient to support the amount of nitrification required to sustain measured DIC fixation rates in the dark ocean. The aim of this study was to quantify the contribution of ammonia oxidizers to DIC fixation in the dark ocean. We used phenylacetylene - a specific inhibitor of the ammonia monooxygenase enzyme - to selectively inhibit ammonia oxidizers during two oceanographic expeditions in the eastern tropical and subtropical Pacific Ocean spanning 35{o} N to 10{o} S. We show that ammonia oxidizers contribute only a small fraction to dark DIC fixation, accounting for 2 to 22% of the depth-integrated rates in the eastern tropical Pacific. The highest contributions were observed at the depth of the nitrification maximum, where ammonia oxidation could account for up to 50% of dark DIC fixation. Our results help to reconcile the observed discrepancies between nitrogen supply and DIC fixation at depth, and provide a new perspective on global ocean chemolithoautotrophy, revealing that the majority of DIC fixation within the lower euphotic zone and below 200 m depth is not fueled by ammonia oxidation.

SignificanceMicrobes in the ocean play important roles in the global carbon cycle and the oceans capacity to sequester carbon. Despite this importance, deciphering the contributions of different microbial metabolic processes to the oceanic carbon budget remains challenging. Particularly in the dark ocean, large discrepancies between organic matter fluxes and measured microbial metabolic rates are observed. We show that abundant chemoautotrophs - ammonia-oxidizing microbes - contribute only a small fraction to dark carbon fixation in the Pacific Ocean, challenging the current view that carbon fixation in the dark ocean is primarily sustained by nitrification. This work advances our understanding of microbial carbon processing, and offers new insights into the long-standing question of the main energy sources fueling carbon fixation in the dark ocean.
]]></description>
<dc:creator>Bayer, B.</dc:creator>
<dc:creator>Kitzinger, K.</dc:creator>
<dc:creator>Paul, N. L.</dc:creator>
<dc:creator>Albers, J. B.</dc:creator>
<dc:creator>Saito, M. A.</dc:creator>
<dc:creator>Wagner, M.</dc:creator>
<dc:creator>Carlson, C. A.</dc:creator>
<dc:creator>Santoro, A. E.</dc:creator>
<dc:date>2024-11-16</dc:date>
<dc:identifier>doi:10.1101/2024.11.16.623942</dc:identifier>
<dc:title><![CDATA[Contribution of ammonia oxidizers to inorganic carbon fixation in the dark ocean]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2024-11-16</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/2024.11.06.622229v1?rss=1">
<title>
<![CDATA[
Strong family- and guild-specific responses of arbuscular mycorrhizal fungi to long-term deficiencies and imbalances of N, P and K 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/2024.11.06.622229v1?rss=1"
</link>
<description><![CDATA[
O_LIMany agroecosystems face nitrogen (N), phosphorus (P) or potassium (K) deficiencies due to imbalanced or insufficient nutrient replenishment after plant biomass harvest. How this affects the symbiosis between plants and arbuscular mycorrhizal fungi (AMF), and the abundance of exploration-based AMF guilds (i.e., rhizophilic, edaphophilic, ancestral) remains largely unknown.
C_LIO_LIWe studied a 70-year nutrient-deficiency experiment in a managed grassland in central Austria, where aboveground biomass was harvested three times annually. N, P and K were fully, partially, or not replenished, causing long-term nutrient deficiencies and imbalances. We analysed AMF communities in soil and roots by DNA/RNA amplicon sequencing and fatty-acid biomarkers, alongside soil and plant community properties.
C_LIO_LISoil AMF communities were affected by N and P deficiencies, while root AMF communities were most susceptible to K deficiency, showing a 50% biomass reduction. We observed distinct guild- and family-specific responses: The edaphophilic guild declined with N deficiency, while the rhizophilic guild decreased with P and K deficiencies. Families within each guild, particularly in the ancestral guild, showed differential responses, indicating complementary nutrient specializations at the family level.
C_LIO_LIOur findings underscore the previously unrecognized role of K deficiency in AMF symbiosis and suggest the existence of nutrient-related functional subgroups within exploration-based AMF guilds.
C_LI
]]></description>
<dc:creator>Jenab, K.</dc:creator>
<dc:creator>Alteio, L.</dc:creator>
<dc:creator>Guseva, K.</dc:creator>
<dc:creator>Gorka, S.</dc:creator>
<dc:creator>Darcy, S.</dc:creator>
<dc:creator>Fuchslueger, L.</dc:creator>
<dc:creator>Canarini, A.</dc:creator>
<dc:creator>Martin, V. S.</dc:creator>
<dc:creator>Wiesenbauer, J.</dc:creator>
<dc:creator>Spiegel, F.</dc:creator>
<dc:creator>Imai, B.</dc:creator>
<dc:creator>Schmidt, H.</dc:creator>
<dc:creator>Hage-Ahmed, K.</dc:creator>
<dc:creator>Poetsch, E.</dc:creator>
<dc:creator>Richter, A.</dc:creator>
<dc:creator>Jansa, J.</dc:creator>
<dc:creator>Kaiser, C.</dc:creator>
<dc:date>2024-11-08</dc:date>
<dc:identifier>doi:10.1101/2024.11.06.622229</dc:identifier>
<dc:title><![CDATA[Strong family- and guild-specific responses of arbuscular mycorrhizal fungi to long-term deficiencies and imbalances of N, P and K]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2024-11-08</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/2024.03.31.587473v1?rss=1">
<title>
<![CDATA[
Shewanella is a putative producer of polyunsaturated fatty acids in the gut soil of the composting earthworm Eisenia fetida 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/2024.03.31.587473v1?rss=1"
</link>
<description><![CDATA[
Polyunsaturated fatty acids (PUFAs) play a crucial role in aiding bacteria to adapt to extreme and stressful environments. While there is a well-established understanding of their production, accrual, and transfer within marine ecosystems, knowledge about terrestrial environments remains limited. Investigation of the intestinal microbiome of earthworms has illuminated the presence of PUFAs presumably of microbial origin, which contrasts with the surrounding soil.

To comprehensively study this phenomenon, a multi-faceted approach was employed, combining fatty acid analysis with amplicon sequencing of the PfaA-KS domain of the anaerobic fatty acid synthase gene (pfa), as well as the 16S rRNA and 18S rRNA genes. This methodology was applied to scrutinize the gut microbiome of Eisenia fetida, its compost-based dietary source, and the resultant castings.

This study unveiled a distinct gut soil ecosystem from input compost and output castings in fatty acid profile as well as type and abundance of organisms. 16S sequencing provided insights into the microbial composition, showing increased relative abundance of certain Pseudomonadota, including Shewanellaceae, and Planctomycetota, including Gemmataceae within the gut microbiome compared to input bulk soil compost, while Actinomycetota and Bacillota were relatively enriched compared to the casted feces. Sequencing of the PfaA-KS domain revealed ASVs belonging primarily to Shewanella. Intriguingly, the 20C PUFAs were identified only in gut-soil samples, though PfaA-KS sequence abundance was highest in output castings, indicating a unique metabolism occurring only in the gut. Overall, the results indicate that Shewanella can explain PUFA enrichment in the gut environment because of pfa gene presence detected via PfaA-KS sequence data.

ImportancePrior research has demonstrated that earthworm microbiomes can potentially harbor PUFAs that are not found within their residing soil environment. Moreover, distinct indicator species have been pinpointed for various microbial genera in earthworm microbiomes. Nevertheless, none of these studies have integrated metataxonomic and fatty acid analysis to explore the origin of PUFA synthesis in any earthworm species, with the objective of identifying the specific organisms and locations responsible for this production. This study suggests that earthworms accumulate PUFAs produced from bacteria, especially Shewanella, activated through the gut ecosystem.
]]></description>
<dc:creator>Wittlinger, J.-P.</dc:creator>
<dc:creator>Castejon, N.</dc:creator>
<dc:creator>Hausmann, B.</dc:creator>
<dc:creator>Berry, D.</dc:creator>
<dc:creator>Schnorr, S. L.</dc:creator>
<dc:date>2024-04-01</dc:date>
<dc:identifier>doi:10.1101/2024.03.31.587473</dc:identifier>
<dc:title><![CDATA[Shewanella is a putative producer of polyunsaturated fatty acids in the gut soil of the composting earthworm Eisenia fetida]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2024-04-01</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/2024.09.27.615339v1?rss=1">
<title>
<![CDATA[
Entorhinal grid-like codes for visual space during memory formation 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/2024.09.27.615339v1?rss=1"
</link>
<description><![CDATA[
Eye movements, such as saccades, allow us to gather information about the environment and, in this way, can shape memory. In non-human primates, saccades are associated with the activity of grid cells in the entorhinal cortex. Grid cells are essential for spatial navigation, but whether saccade-based grid-like signals play a role in human memory formation is currently unclear. Here, human participants underwent functional magnetic resonance imaging (fMRI) and continuous eye gaze monitoring while studying scene images. Recognition memory was probed immediately thereafter. Results revealed saccade-based grid-like codes in the left entorhinal cortex while participants studied the scene images, a finding that was replicated with an independent data set reported here. The grid-related effects were time-locked to activation increases in the frontal eye fields. Most importantly, saccade-based grid-like codes were associated with recognition memory, such that grid-like codes were lower the better participants performed in subsequently recognizing the scene images. Collectively, our findings suggest an entorhinal map of visual space that is timed with neural activity in oculomotor regions, supporting memory formation.
]]></description>
<dc:creator>Graichen, L. P.</dc:creator>
<dc:creator>Linder, M. S.</dc:creator>
<dc:creator>Keuter, L.</dc:creator>
<dc:creator>Jensen, O.</dc:creator>
<dc:creator>Doeller, C. F.</dc:creator>
<dc:creator>Lamm, C.</dc:creator>
<dc:creator>Staudigl, T.</dc:creator>
<dc:creator>Wagner, I. C.</dc:creator>
<dc:date>2024-09-27</dc:date>
<dc:identifier>doi:10.1101/2024.09.27.615339</dc:identifier>
<dc:title><![CDATA[Entorhinal grid-like codes for visual space during memory formation]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2024-09-27</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/2024.09.23.614596v1?rss=1">
<title>
<![CDATA[
Novel high-quality amoeba genomes reveal widespread codon usage mismatch between giant viruses and their hosts 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/2024.09.23.614596v1?rss=1"
</link>
<description><![CDATA[
The need for high-quality protist genomes has prevented in-depth computational and experimental studies of giant virus-host interactions. In addition, our current knowledge of host range is highly biased due to the few hosts used to isolate novel giant viruses. This study presents six high-quality amoeba genomes from known and potential giant virus hosts belonging to two distinct eukaryotic clades: Amoebozoa and Discoba. We employ their genomic data to investigate the predictability of giant virus host range. Using a combination of long and short-read sequencing, we obtained highly contiguous and complete genomes of Acanthamoeba castellanii, Acanthamoeba griffini, Acanthamoeba terricola, Naegleria clarki, Vermamoeba vermiformis, and Willaertia magna, contributing to the collection of sequences for the eukaryotic tree of life. We found that the six amoebae have distinct codon usage patterns and that, contrary to other virus groups, giant viruses often have different and even opposite codon usage with their known hosts. Conversely, giant viruses with matching codon usage are frequently not known to infect or replicate in these hosts. Interestingly, analyses of integrated viral sequences in the amoeba host genomes reveal potential novel virus-host associations. Matching of codon usage preferences is often used to predict virus-host pairs. However, with the broad-scale analyses performed in this study, we demonstrate that codon usage alone appears to be a poor predictor of giant virus host range. We discuss the potential strategies that giant viruses employ to ensure high viral fitness in non-matching hosts. Moreover, this study emphasises the need for more high-quality protist genomes. Finally, the amoeba genomes presented in this study set the stage for future experimental studies to better understand how giant viruses interact with different host species.
]]></description>
<dc:creator>Willemsen, A.</dc:creator>
<dc:creator>Manzano-Marin, A.</dc:creator>
<dc:creator>Horn, M.</dc:creator>
<dc:date>2024-09-25</dc:date>
<dc:identifier>doi:10.1101/2024.09.23.614596</dc:identifier>
<dc:title><![CDATA[Novel high-quality amoeba genomes reveal widespread codon usage mismatch between giant viruses and their hosts]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2024-09-25</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/2024.08.15.608161v1?rss=1">
<title>
<![CDATA[
Human-derived microRNA 21 regulates indole and L-tryptophan biosynthesis transcripts in a prominent gut symbiont 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/2024.08.15.608161v1?rss=1"
</link>
<description><![CDATA[
In the gut, microRNAs (miRNAs) produced by intestinal epithelial cells are secreted into the lumen and can shape the composition and function of the gut microbiome. Crosstalk between gut microbes and the host plays a key role in irritable bowel syndrome (IBS) and inflammatory bowel diseases, yet little is known about how the miRNA-gut microbiome axis contributes to the pathogenesis of these conditions. In this study, we aimed to explore the ability of miR-21, a miRNA that we found decreased in stool samples from IBS patients, to associate with and regulate gut microbiome function. Incubation of human faecal microbiota with miR-21 revealed a rapid association with microbial cells, reproducible across multiple donor samples. Fluorescence-activated cell sorting and sequencing of microbial cells incubated with fluorescently-labelled miR-21 identified organisms belonging to the genera Bacteroides, Limosilactobacillus, Ruminococcus, or Coprococcus which predominantly interacted with miR-21. Surprisingly, these and other genera also interacted with a miRNA scramble control, suggesting that physical interaction and/or uptake of these miRNAs by gut microbiota is not sequence-dependent. Nevertheless, transcriptomic analysis of the gut commensal Bacteroides thetaiotaomicron revealed a miRNA sequence-specific effect on bacterial transcript levels. Supplementation of miR-21, but not of small RNA controls resulted in significantly altered levels of many cellular transcripts and increased transcription of a biosynthetic operon for indole and L-tryptophan, metabolites known to regulate host inflammation and colonic motility. Our study identifies a novel putative miR-21-dependent pathway of regulation of intestinal function through the gut microbiome with implications for gastrointestinal conditions.
]]></description>
<dc:creator>Flanagan, K.</dc:creator>
<dc:creator>Gassner, K.</dc:creator>
<dc:creator>Lang, M.</dc:creator>
<dc:creator>Ozelyte, J.</dc:creator>
<dc:creator>Hausmann, B.</dc:creator>
<dc:creator>Crepaz, D.</dc:creator>
<dc:creator>Pjevac, P.</dc:creator>
<dc:creator>Gasche, C.</dc:creator>
<dc:creator>Berry, D.</dc:creator>
<dc:creator>Vesely, C.</dc:creator>
<dc:creator>Pereira, F. C.</dc:creator>
<dc:date>2024-08-15</dc:date>
<dc:identifier>doi:10.1101/2024.08.15.608161</dc:identifier>
<dc:title><![CDATA[Human-derived microRNA 21 regulates indole and L-tryptophan biosynthesis transcripts in a prominent gut symbiont]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2024-08-15</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/2024.08.09.607300v1?rss=1">
<title>
<![CDATA[
Niche and spatial partitioning restrain ecological equivalence among microbes along aquatic redox gradient 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/2024.08.09.607300v1?rss=1"
</link>
<description><![CDATA[
Microbial metabolic capabilities and interactions shape their niche hypervolume that in turn governs their ecological strategies and ecosystem services. In the context of functional redundancy or ecological equivalence, the focus has been on functional guilds in order to bypass the complex challenge faced by niche theory for disentangling the niche hypervolume. However, in some cases this simplification has been at the expense of ignoring the role of individual genotype of each microbe within a functional guild and fails to explain how the diversity within each functional guild is maintained. In this study, we inspect the metabolic profile of metagenome-assembled genomes along the pronounced redox gradient of the water column in an anchialine cave. Bridging neutral theory of biodiversity and biogeography and niche theory, our analysis uses focal metabolic capabilities while also incorporating individuality by looking into background metabolic capabilities of each individual and further includes spatial distribution of microbes to delineate their niche space. Our results emphasize that differences in background metabolic capabilities are critical for furnishing the niche hypervolume of microbes carrying the same focal metabolic capability and refute their ecological equivalence with their spatial distribution further enables niche partitioning among them.
]]></description>
<dc:creator>Kajan, K.</dc:creator>
<dc:creator>Kirkegaard, R.</dc:creator>
<dc:creator>Pjevac, P.</dc:creator>
<dc:creator>Orlic, S.</dc:creator>
<dc:creator>Mehrshad, M.</dc:creator>
<dc:date>2024-08-09</dc:date>
<dc:identifier>doi:10.1101/2024.08.09.607300</dc:identifier>
<dc:title><![CDATA[Niche and spatial partitioning restrain ecological equivalence among microbes along aquatic redox gradient]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2024-08-09</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/2024.08.01.606122v1?rss=1">
<title>
<![CDATA[
Distinct microbial communities are linked to organic matter properties in millimetre-sized soil aggregates 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/2024.08.01.606122v1?rss=1"
</link>
<description><![CDATA[
Soils provide essential ecosystem services and represent the most diverse habitat on Earth. It has been suggested that the presence of various physico-chemically heterogenous microhabitats supports the enormous diversity of microbial communities in soil. However, little is known about the relationship between microbial communities and their immediate environment at the micro- to millimetre-scale. In this study, we examined whether bacteria, archaea, and fungi organise into distinct communities in individual 2-millimetre-sized soil aggregates and compared them to communities of homogenized bulk soil samples. Furthermore, we investigated their relationship to their local environment by concomitantly determining microbial community structure and physico-chemical properties from the same individual aggregates. Aggregate-communities displayed exceptionally high beta-diversity, with 3-4 aggregates collectively capturing more diversity than their homogenized parent soil core. Up to 20-30% of ASVs (particularly rare ones) were unique to individual aggregates selected within a few centimetres. Aggregates and bulk soil samples showed partly different dominant phyla, indicating that taxa that are potentially driving biogeochemical processes at the small scale may not be recognized when analysing larger soil volumes. Microbial community composition and richness of individual aggregates were closely related to aggregate-specific carbon and nitrogen content, carbon stable-isotope composition, and soil moisture, indicating that aggregates provide a stable environment for sufficient time to allow co-development of communities and their environment. We conclude that the soil microbiome is a metacommunity of variable subcommunities. Our study highlights the necessity to study small, spatially coherent soil samples to better understand controls of community structure and community-mediated processes in soils.
]]></description>
<dc:creator>Simon, E.</dc:creator>
<dc:creator>Guseva, K.</dc:creator>
<dc:creator>Darcy, S.</dc:creator>
<dc:creator>Alteio, L.</dc:creator>
<dc:creator>Pjevac, P.</dc:creator>
<dc:creator>Schmidt, H.</dc:creator>
<dc:creator>Jenab, K.</dc:creator>
<dc:creator>Ranits, C.</dc:creator>
<dc:creator>Kaiser, C.</dc:creator>
<dc:date>2024-08-03</dc:date>
<dc:identifier>doi:10.1101/2024.08.01.606122</dc:identifier>
<dc:title><![CDATA[Distinct microbial communities are linked to organic matter properties in millimetre-sized soil aggregates]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2024-08-03</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/2023.10.03.560709v1?rss=1">
<title>
<![CDATA[
Bacteria face trade-offs in the decomposition of complex biopolymers 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/2023.10.03.560709v1?rss=1"
</link>
<description><![CDATA[
Although depolymerization of complex carbohydrates is a growth-limiting bottleneck for microbial decomposers, we still lack understanding about how the production of different types of extracellular enzymes affect individual microbes and in turn the performance of whole decomposer communities. In this work we use a theoretical model to evaluate the potential trade-offs faced by microorganisms in biopolymer decomposition which arise due to the varied biochemistry of different depolymerizing enzyme classes. We specifically consider two broad classes of depolymerizing extracellular enzymes, which are widespread across microbial taxa: exo-enzymes that cleave small units from the ends of polymer chains and endo-enzymes that act at random positions generating degradation products of varied sizes. Our results demonstrate a fundamental trade-off in the production of these enzymes, which is independent of systems complexity and which appears solely from the intrinsically different temporal depolymerization dynamics. As a consequence, specialists that produce either exo- or only endo-enzymes limit their growth to high or low substrate conditions, respectively. Conversely, generalists that produce both enzymes in an optimal ratio expand their niche and benefit from the synergy between the two enzymes. Finally, our results show that, in spatially-explicit environments, consortia composed of endo- and exo-specialists can only exist under oligotrophic conditions. In summary, our analysis demonstrates that the (evolutionary or ecological) selection of a depolymerization pathway will affect microbial fitness under low- or high substrate conditions, with impacts on the ecological dynamics of microbial communities. It provides a possible explanation why many polysaccharide degraders in nature show the genetic potential to produce both of these enzyme classes.

Author summaryThe decomposition of polysaccharides by microbes is a key process in the global carbon cycle. It requires the joint action of a variety of microbially-produced extracellular enzymes. They can be broadly classified into endo-enzymes, that act in the middle of polymers, and exo-enzymes, that cleave units from polymer ends. Little is known about the benefits for microbes producing a certain enzyme type and the interplay between enzyme producing strategies in mixed communities. This hampers our comprehensive understanding of decomposition in terrestrial and marine ecosystems and thus limits the prediction of decomposition processes, for example in a changing climate.

Based on theoretical modelling, we revealed a fundamental trade-off in the action of these enzymes. While exo-enzymes are more efficient at high substrate conditions, endo-enzymes perform better when substrate is low. Generalists producing both enzymes expand their ecological niche of substrate availability compared to specialists only producing one of the two types. Complementary specialists only co-exist in oligotrophic conditions. We conclude that producing enzymes for specific steps within polymer degradation represents relevant ecological strategies for microbes in decomposer communities.
]]></description>
<dc:creator>Guseva, K.</dc:creator>
<dc:creator>Mohrlok, M.</dc:creator>
<dc:creator>Alteio, L.</dc:creator>
<dc:creator>Schmidt, H.</dc:creator>
<dc:creator>Pollak, S.</dc:creator>
<dc:creator>Kaiser, C.</dc:creator>
<dc:date>2023-10-03</dc:date>
<dc:identifier>doi:10.1101/2023.10.03.560709</dc:identifier>
<dc:title><![CDATA[Bacteria face trade-offs in the decomposition of complex biopolymers]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2023-10-03</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/2024.07.06.601931v1?rss=1">
<title>
<![CDATA[
Acidotolerant soil nitrite oxidiser 'Candidatus Nitrobacter laanbroekii' NHB1 alleviates constraints on growth of acidophilic soil ammonia oxidisers 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/2024.07.06.601931v1?rss=1"
</link>
<description><![CDATA[
Nitrobacter strain NHB1 is a nitrite-oxidising bacterium previously co-enriched with the neutrophilic ammonia-oxidising bacterium Nitrosospira AHB1, a consortium that nitrifies under acidic conditions. Here we characterise the growth of isolated Nitrobacter strain NHB1 as a function of pH and nitrite (NO2-) concentration, and its influence on the activity of acidophilic soil ammonia-oxidising archaea (AOA) in co-culture. NHB1 is acidotolerant and grows optimally at pH 6.0 (range 5.0 - 7.5) at initial NO2- concentrations of 500 {micro}M. However, the optimum decreases to pH 5.0 at lower initial NO2- concentrations closer to those found in soil, with detectable growth down to pH 3.5. NHB1 has a comparatively high affinity for NO2- with an apparent-half-saturation constant (54 {micro}M) one order of magnitude lower than its closest relative, the neutrophilic strain Nitrobacter hamburgensis X14. In co-culture, NHB1 enhances the growth of acidophilic AOA. Specifically, Nitrosotalea devaniterrae Nd1 and Nitrosotalea sinensis Nd2 are sensitive to NO2--derived compounds and only oxidise [~]200-300 {micro}M ammonia (NH3) in batch cultures. However, in co-culture with NHB1, pH ranges were lowered by [~]0.5 pH units and both strains could oxidise up to 2.7-2.9 mM NH3, only limited by buffering capacity. NHB1 possesses a cyanase facilitating reciprocal cross-feeding via generating cyanate-derived NH3 and utilising AOA-derived NO2-. Removal of NO2- is likely crucial for nitrifier growth in acidic soils and this study highlights the importance of considering substrate and metabolic product concentrations when characterising physiology. Genome analysis reveals that NHB1 is distinct from validated species and the name  Nitrobacter laanbroekii is proposed.
]]></description>
<dc:creator>Hink, L.</dc:creator>
<dc:creator>Bachtsevani, E.</dc:creator>
<dc:creator>Meng, Y.</dc:creator>
<dc:creator>Sedlacek, C. J.</dc:creator>
<dc:creator>Lee, S.</dc:creator>
<dc:creator>Daims, H.</dc:creator>
<dc:creator>Wagner, M.</dc:creator>
<dc:creator>Gubry-Rangin, C.</dc:creator>
<dc:creator>de Boer, W.</dc:creator>
<dc:creator>Hazard, C.</dc:creator>
<dc:creator>Prosser, J. I.</dc:creator>
<dc:creator>Nicol, G. W.</dc:creator>
<dc:date>2024-07-07</dc:date>
<dc:identifier>doi:10.1101/2024.07.06.601931</dc:identifier>
<dc:title><![CDATA[Acidotolerant soil nitrite oxidiser 'Candidatus Nitrobacter laanbroekii' NHB1 alleviates constraints on growth of acidophilic soil ammonia oxidisers]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2024-07-07</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/2024.06.27.600767v1?rss=1">
<title>
<![CDATA[
Microflora Danica: the atlas of Danish environmental microbiomes 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/2024.06.27.600767v1?rss=1"
</link>
<description><![CDATA[
The last 20 years have witnessed unprecedented advances in revealing the microbiomes underpinning important processes in natural and human associated environments. Recent large-scale metagenome surveys record the variety of microbial life in the oceans1, wastewater2, human gut3,4, and earth5,6, with compilations encompassing thousands of public datasets7-13. So far, large-scale microbiome studies either miss functional information or consistency in sample processing, and although they may cover thousands of locations, these are missing resolution, sparsely located, or lacking metadata. Here, we present Microflora Danica, an atlas of Danish environmental microbiomes, encompassing 10,686 shotgun metagenomes and 449 full-length 16S and 18S rRNA datasets linked to a detailed 5 level habitat classification scheme. We determine that while human-disturbed habitats have high alpha diversity, the same species reoccur, revealing hidden homogeneity and underlining the importance of natural systems for total species (gamma) diversity. In-depth studies of nitrifiers, a functional group closely linked to climate change, challenge existing perceptions regarding habitat preference and discover several novel nitrifiers as more abundant than canonical nitrifiers. Together, the Microflora Danica dataset provides an unprecedented resource and the foundation for answering fundamental questions underlying microbial ecology: what drives microbial diversity, distribution and function.
]]></description>
<dc:creator>Singleton, C. M.</dc:creator>
<dc:creator>Jensen, T. B.</dc:creator>
<dc:creator>Delogu, F.</dc:creator>
<dc:creator>Sorensen, E. A.</dc:creator>
<dc:creator>Jorgensen, V. R.</dc:creator>
<dc:creator>Karst, S. M.</dc:creator>
<dc:creator>Yang, Y.</dc:creator>
<dc:creator>Knudsen, K. S.</dc:creator>
<dc:creator>Sereika, M.</dc:creator>
<dc:creator>Petriglieri, F.</dc:creator>
<dc:creator>Knuttson, S.</dc:creator>
<dc:creator>Dall, S. M.</dc:creator>
<dc:creator>Kirkegaard, R. H.</dc:creator>
<dc:creator>Kristensen, J. M.</dc:creator>
<dc:creator>Woodcroft, B. J.</dc:creator>
<dc:creator>Speth, D. R.</dc:creator>
<dc:creator>Aroney, S.</dc:creator>
<dc:creator>The Microflora Danica Consortium,</dc:creator>
<dc:creator>Wagner, M.</dc:creator>
<dc:creator>Dueholm, M. M.</dc:creator>
<dc:creator>Nielsen, P. H.</dc:creator>
<dc:creator>Albertsen, M.</dc:creator>
<dc:date>2024-06-27</dc:date>
<dc:identifier>doi:10.1101/2024.06.27.600767</dc:identifier>
<dc:title><![CDATA[Microflora Danica: the atlas of Danish environmental microbiomes]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2024-06-27</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/2024.05.25.595854v1?rss=1">
<title>
<![CDATA[
Genome-wide sweeps create fundamental ecological units in the human gut microbiome 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/2024.05.25.595854v1?rss=1"
</link>
<description><![CDATA[
The human gut microbiome is shaped by diverse selective forces originating from the host and associated environmental factors, and in turn profoundly influences health and disease. While the association of microbial lineages with various conditions has been shown at different levels of phylogenetic differentiation, it remains poorly understood to what extent unifying adaptive mechanisms sort microbial lineages into ecologically differentiated populations. Here we show that a pervasive mechanism differentiating bacteria in the microbiome are genome-wide selective sweeps, leading to population structure akin to global epidemics across geographically and ethnically diverse human populations. Such sweeps arise when an adaptation allows a clone to outcompete others within its niche followed by re-diversification, and manifest as clusters of closely related genomes on long branches in phylogenetic trees. This structure is revealed by excluding recombination events that mask the clonal descent of the genomes, and we find that genome-wide sweeps originate under a wide regime of recombination rates in at least 66 taxa from 25 bacterial families. Estimated ages of divergence suggest sweep clusters can spread globally within decades, and this process has occurred repeatedly throughout human history. We show, as an example, that the ecological differentiation of sweep clusters forms populations highly associated with age and colorectal cancer. Our analysis elucidates an evolutionary mechanism for the observation of stably inherited strains with differential associations and provides a theoretical foundation for analyzing adaptation among co-occurring microbial populations.
]]></description>
<dc:creator>Yu, X. A.</dc:creator>
<dc:creator>Strachan, C. R.</dc:creator>
<dc:creator>Herbold, C. W.</dc:creator>
<dc:creator>Lang, M.</dc:creator>
<dc:creator>Gasche, C.</dc:creator>
<dc:creator>Makristathis, A.</dc:creator>
<dc:creator>Segata, N.</dc:creator>
<dc:creator>Pollak, S.</dc:creator>
<dc:creator>Tett, A.</dc:creator>
<dc:creator>Polz, M. F.</dc:creator>
<dc:date>2024-05-25</dc:date>
<dc:identifier>doi:10.1101/2024.05.25.595854</dc:identifier>
<dc:title><![CDATA[Genome-wide sweeps create fundamental ecological units in the human gut microbiome]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2024-05-25</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/2023.11.08.566030v1?rss=1">
<title>
<![CDATA[
Insights into the early-life chemical exposome of Nigerian infants and potential correlations with the developing gut microbiome 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/2023.11.08.566030v1?rss=1"
</link>
<description><![CDATA[
Early-life exposure to natural and synthetic chemicals can impact acute and chronic health conditions. Here, a suspect screening workflow anchored on high-resolution mass spectrometry was applied to elucidate xenobiotics in breast milk and matching stool samples collected from Nigerian mother-infant pairs (n = 11) at three time points. Potential correlations between xenobiotic exposure and the developing gut microbiome, as determined by 16S rRNA gene amplicon sequencing, were subsequently explored. Overall, 12,192 and 16,461 features were acquired in the breast milk and stool samples, respectively. Following quality control and suspect screening, 562 and 864 features remained, respectively, with 149 of these features present in both matrices. Taking advantage of 242 authentic reference standards measured for confirmatory purposes of food bio-actives and toxicants, 34 features in breast milk and 68 features in stool were identified and semi-quantified. Moreover, 51 and 78 features were annotated with spectral library matching, as well as 416 and 652 by in silico fragmentation tools in breast milk and stool, respectively. The analytical workflow proved its versatility to simultaneously determine a diverse panel of chemical classes including mycotoxins, endocrine-disrupting chemicals (EDCs), antibiotics, plasticizers, perfluorinated alkylated substances (PFAS), and pesticides although it was originally optimized for polyphenols. Spearman rank correlation of the identified features revealed significant correlations between chemicals of the same classification such as polyphenols. One-way ANOVA and differential abundance analysis of the data obtained from stool samples revealed that molecules of plant-based origin were elevated when complementary foods were introduced to the infants diets. Annotated compounds in the stool, such as tricetin, positively correlated with the genus Blautia. Moreover, vulgaxanthin negatively correlated with Escherichia-Shigella. Despite the limited sample size, this exploratory study provides high-quality exposure data of matched biospecimens obtained from mother-infant pairs in sub-Saharan Africa and shows potential correlations between the chemical exposome and the gut microbiome.

Highlights- Suspect screening of exposure biomarkers in human breast milk and infant stool.
- 542 features in breast milk and 864 in stool were identified or annotated.
- Consumption of complementary foods influenced the chemical exposure of infants.
- Correlations between xenobiotics in both biological matrices evaluated.
- Dietary exposure correlated to the stool microbiome composition.


Graphical abstract

O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=80 SRC="FIGDIR/small/566030v2_ufig1.gif" ALT="Figure 1">
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]]></description>
<dc:creator>Oesterle, I.</dc:creator>
<dc:creator>Ayeni, K. I.</dc:creator>
<dc:creator>Ezekiel, C. N.</dc:creator>
<dc:creator>Berry, D.</dc:creator>
<dc:creator>Rompel, A.</dc:creator>
<dc:creator>Warth, B.</dc:creator>
<dc:date>2023-11-11</dc:date>
<dc:identifier>doi:10.1101/2023.11.08.566030</dc:identifier>
<dc:title><![CDATA[Insights into the early-life chemical exposome of Nigerian infants and potential correlations with the developing gut microbiome]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2023-11-11</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/2024.04.27.591451v1?rss=1">
<title>
<![CDATA[
The interplay between light, arsenic and H2O2 controls oxygenic photosynthesis in a Precambrian analog cyanobacterial mat. 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/2024.04.27.591451v1?rss=1"
</link>
<description><![CDATA[
The delayed rise of atmospheric oxygen, despite the early evolution of oxygenic photosynthesis (OP), remains a central puzzle in Earth history. Numerous ecological and geochemical constraints on OP have been proposed, but the role of environmental stressors at the physiological and ecosystem level is poorly understood. Here we show that Chl-f-harboring cyanobacteria in a high-altitude Andean microbial mat - an analog for Precambrian ecosystems - switch from OP to arsenite-driven anoxygenic photosynthesis (AP) under high light. Using microsensor profiling, mat incubations, and metatranscriptomics, we show that this shift is triggered by the accumulation of reactive oxygen species (ROS), especially hydrogen peroxide, which suppresses OP. Instead of ceasing activity, cyanobacteria reroute electron flow, using arsenite as the electron donor to sustain photosynthesis while avoiding both intracellular ROS from OP and extracellular ROS from aerobic arsenite oxidation. This switch is reversible and coordinated with diel cycles of light and arsenic speciation, sustained by a cryptic arsenic redox cycle, continuously regenerating arsenite for AP. Although the enzymatic basis remains unresolved, these findings reveal a hidden layer of metabolic plasticity in cyanobacteria and suggest that oxidative stress-responsive metabolic shifts may have supported early phototroph survival while limiting oxygen release - potentially contributing to Earths protracted oxygenation.
]]></description>
<dc:creator>Castillejos Sepulveda, A.</dc:creator>
<dc:creator>Speth, D. R.</dc:creator>
<dc:creator>Kerl, C.</dc:creator>
<dc:creator>Doherty-Weason, D.</dc:creator>
<dc:creator>Vignale, F. A.</dc:creator>
<dc:creator>Santha, K.</dc:creator>
<dc:creator>Chennu, A.</dc:creator>
<dc:creator>Mohr, W.</dc:creator>
<dc:creator>Merz, E.</dc:creator>
<dc:creator>de Beer, D.</dc:creator>
<dc:creator>Farias, M. E.</dc:creator>
<dc:creator>Klatt, J.</dc:creator>
<dc:date>2024-04-27</dc:date>
<dc:identifier>doi:10.1101/2024.04.27.591451</dc:identifier>
<dc:title><![CDATA[The interplay between light, arsenic and H2O2 controls oxygenic photosynthesis in a Precambrian analog cyanobacterial mat.]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2024-04-27</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/2024.04.12.589189v1?rss=1">
<title>
<![CDATA[
Discordance between phylogenomic datasets in aphids: who is telling the truth? 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/2024.04.12.589189v1?rss=1"
</link>
<description><![CDATA[
Aphids (Hemiptera: Aphididae) are intensively studied due to their significance as pests and their captivating biological traits. Despite this considerable research interest, the evolutionary history of this insect family is poorly understood. Recent phylogenomic analyses have produced conflicting topologies, particularly at deep nodes, complicating our understanding of aphid trait evolution. In this work, we aimed to produce new data to unravel the backbone phylogeny of aphids. We sequenced partial and whole mitochondrial genomes from 87 species that were added to 31 published mitochondria. We additionally sequenced 42 nuclear loci across 95 aphid species and sourced 146 genes from 12 new and 61 published genomes from the primary aphid obligate endosymbiont, Buchnera aphidicola. We obtain data from these three sources for a subset of 51 aphid species, facilitating a comparative analysis of their phylogenetic signals. Our analyses confirm the monophyly of subfamilies, validating current taxonomic classifications, except for Eriosomatinae and Calaphidinae. However, relationships between subfamilies remain contentious in both mitochondrial and nuclear phylogenies. The topologies obtained with Buchnera appear fully resolved but exhibit some discordance with host phylogenies at deep evolutionary scales and conflict with views on the evolution of aphid morphology. We discuss alternative hypotheses for these discrepancies. Finally, the paucity of phylogenetic information at deep phylogenetic scales may stem from an initial rapid radiation. Though challenging to establish, this scenario may inherently hinder resolution in aphid phylogenetics.
]]></description>
<dc:creator>Jousselin, E.</dc:creator>
<dc:creator>Coeur d'acier, A.</dc:creator>
<dc:creator>Clamens, A.-l.</dc:creator>
<dc:creator>Galan, M.</dc:creator>
<dc:creator>Cruaud, C.</dc:creator>
<dc:creator>Barbe, V.</dc:creator>
<dc:creator>Manzano-Marin, A.</dc:creator>
<dc:date>2024-04-15</dc:date>
<dc:identifier>doi:10.1101/2024.04.12.589189</dc:identifier>
<dc:title><![CDATA[Discordance between phylogenomic datasets in aphids: who is telling the truth?]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2024-04-15</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/2024.04.10.588810v1?rss=1">
<title>
<![CDATA[
Unexpectedly dense colonization of soil pore space by microbes 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/2024.04.10.588810v1?rss=1"
</link>
<description><![CDATA[
Pore surfaces in soil are considered to be sparsely colonised, dispersed only with isolated cells or colonies of bacteria and archaea. Here, we question this  empty space-concept by combining microstructure analysis with molecular biology and provide a data-driven update on habitable surface areas (HSA) in soil. Our unique approach allowed us to provide 1) evidence that microbial densities in soil have been underestimated for decades and 2) two-dimensional simulations of their potential distribution within the soil pore space. Our results demonstrate the need for a new perspective on how densely soil is colonised, with implications for how we think of basic ecological processes such as microbial motility or predation, and how microbial processes, including organic matter dynamics, are ultimately modelled.
]]></description>
<dc:creator>Schmidt, H.</dc:creator>
<dc:creator>Schlueter, S.</dc:creator>
<dc:creator>Raynaud, X.</dc:creator>
<dc:creator>Felde, V. J.</dc:creator>
<dc:creator>Zeller-Plumhoff, B.</dc:creator>
<dc:creator>Richter, A.</dc:creator>
<dc:creator>Nunan, N.</dc:creator>
<dc:date>2024-04-13</dc:date>
<dc:identifier>doi:10.1101/2024.04.10.588810</dc:identifier>
<dc:title><![CDATA[Unexpectedly dense colonization of soil pore space by microbes]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2024-04-13</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/2024.04.10.588852v1?rss=1">
<title>
<![CDATA[
Expanding the cultivated human archaeome by targeted isolation of novel Methanobrevibacter strains from fecal samples 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/2024.04.10.588852v1?rss=1"
</link>
<description><![CDATA[
Archaea are integral components of the human microbiome but persist as understudied entities within the gastrointestinal tract (GIT), primarily due to the lack of cultured representatives for comprehensive mechanistic investigations. With only four Methanobrevibacter smithii isolates from humans available according to the Global Catalogue of Microorganisms (GCM), the existing cultures fail to adequately represent the observed diversity, as underscored by recent findings.

This study introduces a targeted cultivation method for enriching methanogenic archaea from human fecal samples. Applied to 16 stool samples from healthy and diseased donors, the method aimed to genomically characterize the archaeal cultures and establish correlations with gastrointestinal disorders. The procedure combines methane breath testing, in silico metabolic modelling, media optimization, FACS, dilution series, and genomic sequencing through Nanopore technology. Additional analyses include co-cultured bacteriome, comparative genomics of archaeal genomes, functional comparisons, and structure-based protein function prediction of unknown differential traits.

Successful establishment of stable archaeal cultures from 14 out of 16 fecal samples yielded nine previously uncultivated strains, eight of which were absent from a recent archaeome genome catalog. Comparative genomic and functional assessments of Methanobrevibacter smithii and Candidatus Methanobrevibacter intestini strains from diverse participant cohorts revealed features potentially associated with gastrointestinal diseases.

This work substantially broadens the scope of available archaeal representatives for functional and mechanistic studies in the human GIT. The established protocol facilitates the cultivation of methanogenic archaea from nearly every human fecal sample, offering insights into the adaptability of Candidatus Methanobrevibacter intestini genomes in critical microbiome situations.
]]></description>
<dc:creator>Duller, S.</dc:creator>
<dc:creator>Vrbancic, S.</dc:creator>
<dc:creator>Szydlowski, L.</dc:creator>
<dc:creator>Mahnert, A.</dc:creator>
<dc:creator>Blohs, M.</dc:creator>
<dc:creator>Predl, M.</dc:creator>
<dc:creator>Kumpitsch, C.</dc:creator>
<dc:creator>Zrim, V.</dc:creator>
<dc:creator>Hoegenauer, C.</dc:creator>
<dc:creator>Kosciolek, T.</dc:creator>
<dc:creator>Schmitz, R. A.</dc:creator>
<dc:creator>Eberhard, A.</dc:creator>
<dc:creator>Dragovan, M.</dc:creator>
<dc:creator>Schmidberger, L.</dc:creator>
<dc:creator>Zurabischvili, T.</dc:creator>
<dc:creator>Weinberger, V.</dc:creator>
<dc:creator>Moser, A. M.</dc:creator>
<dc:creator>Kolb, D.</dc:creator>
<dc:creator>Pernitsch, D.</dc:creator>
<dc:creator>Mohammadzadeh, R.</dc:creator>
<dc:creator>Kuehnast, T.</dc:creator>
<dc:creator>Rattei, T.</dc:creator>
<dc:creator>Moissl-Eichinger, C.</dc:creator>
<dc:date>2024-04-11</dc:date>
<dc:identifier>doi:10.1101/2024.04.10.588852</dc:identifier>
<dc:title><![CDATA[Expanding the cultivated human archaeome by targeted isolation of novel Methanobrevibacter strains from fecal samples]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2024-04-11</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/2024.02.27.582363v1?rss=1">
<title>
<![CDATA[
The predicted secreted proteome of activated sludge microorganisms indicate distinct nutrient niches 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/2024.02.27.582363v1?rss=1"
</link>
<description><![CDATA[
In wastewater treatment plants (WWTPs) complex microbial communities process diverse chemical compounds from sewage. Secreted proteins are critical because many are the first to interact with or degrade external (macro)molecules. To better understand microbial functions in WWTPs, we predicted secreted proteomes of WWTP microbiota from more than 1000 high-quality metagenome-assembled genomes (MAGs) from 23 Danish WWTPs with biological nutrient removal. Focus was placed on examining secreted catabolic exoenzymes that target major classes of macromolecules. We demonstrate that Bacteroidota have high potential to digest complex polysaccharides, but also proteins and nucleic acids. Poorly understood activated sludge members of Acidobacteriota and Gemmatimonadota also have high capacities for extracellular polysaccharide digestion. Secreted nucleases are encoded by 61% of MAGs indicating an importance for extracellular DNA and/or RNA digestion in WWTPs. Secreted lipases were the least-common macromolecule-targeting enzymes predicted, encoded mainly by Gammaproteobacteria and Myxococcota. In contrast, diverse taxa encode extracellular peptidases, indicating that proteins are widely used nutrients. Diverse secreted multi-heme cytochromes suggest capabilities for extracellular electron-transfer by various taxa, including some Bacteroidota that encode undescribed cytochromes with >100 heme-binding motifs. Myxococcota have exceptionally large secreted protein complements, probably related to predatory lifestyles and/or complex cell cycles. Many Gammaproteobacteria MAGs (mostly former Betaproteobacteria) encode few or no secreted hydrolases, but many periplasmic substrate-binding proteins and ABC- and TRAP-transporters, suggesting they are mostly sustained by small molecules. Together, this study provides a comprehensive overview of how WWTPs microorganisms interact with the environment, providing new insights into their functioning and niche partitioning.

ImportanceWastewater treatment plants are critical biotechnological systems that clean wastewater, allowing the water to reenter the environment and limit eutrophication and pollution. They are also increasingly important for recovery of resources. They function primarily by the activity of microorganisms, which act as a  living sponge, taking-up and transforming nutrients, organic material and pollutants. Despite much research, many microorganisms in WWTPs are uncultivated and poorly characterized, limiting our understanding of their functioning. Here, we analyzed a large collection of high-quality metagenome-assembled genomes from WWTPs for encoded secreted enzymes and proteins, with special emphasis on those used to degrade organic material. This analysis showed highly distinct secreted proteome profiles among different major phylogenetic groups of microorganisms, thereby providing new insights into how different groups function and co-exist in activated sludge. This knowledge will contribute to a better understanding of how to efficiently manage and exploit WWTP microbiomes.
]]></description>
<dc:creator>Wasmund, K.</dc:creator>
<dc:creator>Singleton, C.</dc:creator>
<dc:creator>Dueholm, M. S.</dc:creator>
<dc:creator>Wagner, M.</dc:creator>
<dc:creator>Nielsen, P. H.</dc:creator>
<dc:date>2024-02-29</dc:date>
<dc:identifier>doi:10.1101/2024.02.27.582363</dc:identifier>
<dc:title><![CDATA[The predicted secreted proteome of activated sludge microorganisms indicate distinct nutrient niches]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2024-02-29</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/2024.01.29.577165v1?rss=1">
<title>
<![CDATA[
Mechanism of bacterial predation via ixotrophy 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/2024.01.29.577165v1?rss=1"
</link>
<description><![CDATA[
Predation allows bacteria to access alternative substrates in low-nutrient conditions. Ixotrophy has been proposed as a predatory lifestyle of multicellular filamentous bacteria in aquatic environments; however, the molecular mechanism remains unknown.

Here we uncover by a multidisciplinary approach that ixotrophy requires the interplay of multiple cellular machineries and a regulatory mechanism. Attacker-prey contacts are established by gliding motility and extracellular grappling hook-like structures that bind prey flagella. Cryo-electron microscopy identifies the grappling hooks as a heptameric assembly of a Type 9 Secretion System substrate. Cryo-electron tomography and functional assays show that killing is mediated by puncturing of the prey cell using a Type 6 Secretion System, possibly triggered by extracellular antennae. Single-cell analyses with stable isotope-labeled prey demonstrate that prey components are taken up by the attacker. Depending on nutrient availability, ixotrophy is switched off by endogenous Insertion Sequence Elements and re-activated through their excision. A marine metagenomic time series provides evidence for coupled dynamics of ixotrophic bacteria and their prey.

Our study reveals the complex mechanism of a conserved microbial predatory lifestyle and indicates the need for its regulation in conditions where the expression of costly pathways is dispensable.
]]></description>
<dc:creator>Lien, Y.-W.</dc:creator>
<dc:creator>Amendola, D.</dc:creator>
<dc:creator>Lee, K. S.</dc:creator>
<dc:creator>Bartlau, N.</dc:creator>
<dc:creator>Xu, J.</dc:creator>
<dc:creator>Furusawa, G.</dc:creator>
<dc:creator>Polz, M. F.</dc:creator>
<dc:creator>Stocker, R.</dc:creator>
<dc:creator>Weiss, G. L.</dc:creator>
<dc:creator>PIlhofer, M.</dc:creator>
<dc:date>2024-01-29</dc:date>
<dc:identifier>doi:10.1101/2024.01.29.577165</dc:identifier>
<dc:title><![CDATA[Mechanism of bacterial predation via ixotrophy]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2024-01-29</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/2024.01.15.574570v1?rss=1">
<title>
<![CDATA[
Nitrous oxide respiration in acidophilic methanotrophs 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/2024.01.15.574570v1?rss=1"
</link>
<description><![CDATA[
Methanotrophic bacteria mitigate methane (CH4) emissions from natural environments. Although aerobic methanotrophs are considered strict aerobes, they are often highly abundant in extremely hypoxic and even anoxic environments. Despite the presence of denitrification genes, it remains to be verified whether denitrification contributes to their growth. Here, we revealed that two acidophilic methanotrophs encoding N2O reductase (clade I and type II nosZ, respectively): Methylocella tundrae T4 and Methylacidiphilum caldifontis IT6, respired N2O and grew anaerobically on diverse non-methane substrates, including methanol, C-C substrates, and hydrogen. However, NO3 - and NO2 - could be reduced during methanol oxidation in Methylocella tundrae T4 and Methylocella silvestris BL2 without significantly increasing cell biomass. The lack of growth on methanol + NO3- or NO2- was likely due to the production of toxic reactive nitrogen species and C1 metabolites. However, the oxidation of pyruvate, a C3 electron donor, combined with NO3- or NO2- reduction resulted in anaerobic growth of Methylocella tundrae T4 and Methylocella silvestris BL2. In the extreme acidophile, Methylacidiphilum caldifontis IT6, N2O respiration supported cell growth at an extremely acidic pH of 2.0. In Methylocella tundrae T4, simultaneous consumption of N2O and CH4 was observed in suboxic conditions, both in microrespirometry and growth experiments, indicating the robustness of its N2O reductase activity in the presence of O2. Furthermore, CH4 oxidation per O2 reduced in O2-limiting conditions increased when N2O was added, indicating that cells of T4 can direct more O2 towards methane monooxygenase when respiring N2O as a terminal electron acceptor. Upregulation of nosZ and distinct repertories of methanol dehydrogenase-encoding genes (XoxF- and MxaFI-type) in Methylocella tundrae T4 cells grown anaerobically on methanol with N2O as the sole electron acceptor indicated adaptation mechanisms to anoxia. Our findings demonstrate that some methanotrophs can respire N2O independently or in tandem with O2, significantly expanding their potential ecological niche and paving the way for enhanced growth and survival in dynamic environments. This metabolic capability has application potential for simultaneously mitigating the emissions of the key greenhouse gases, CO2, CH4, and N2O, from natural and engineered environments.
]]></description>
<dc:creator>Awala, S. I.</dc:creator>
<dc:creator>Gwak, J.-H.</dc:creator>
<dc:creator>Kim, Y.</dc:creator>
<dc:creator>Jung, M.-Y.</dc:creator>
<dc:creator>Dunfield, P. F.</dc:creator>
<dc:creator>Wagner, M.</dc:creator>
<dc:creator>Rhee, S.-K.</dc:creator>
<dc:date>2024-01-16</dc:date>
<dc:identifier>doi:10.1101/2024.01.15.574570</dc:identifier>
<dc:title><![CDATA[Nitrous oxide respiration in acidophilic methanotrophs]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2024-01-16</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/2024.01.08.574571v1?rss=1">
<title>
<![CDATA[
Candidatus Nitrosocosmicus members are the dominant archaea associated with pepper (Capsicum annuum L.) and ginseng (Panax ginseng C.A. Mey.) plants rhizospheres 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/2024.01.08.574571v1?rss=1"
</link>
<description><![CDATA[
BackgroundAlthough archaea are widespread in terrestrial environments, little is known about the selection forces that shape their composition, functions, survival, and proliferation strategies in the rhizosphere. The ammonia-oxidizing archaea (AOA), which are abundant in soil environments, catalyze the first step of nitrification and have the potential to influence plant growth and development significantly.

ResultsBased on archaeal 16S rRNA and amoA gene (encoding the ammonia monooxygenase subunit A) amplicon sequencing analysis, distinct archaeal communities dominated by AOA were found to be associated with the root systems of pepper (Capsicum annuum L.) and ginseng (Panax ginseng C.A. Mey.) plants compared to bulk soil not penetrated by roots. AOA related to "Candidatus Nitrosocosmicus", which, unlike most other AOA, harbor genes encoding manganese catalase (MnKat), dominated rhizosphere soils, and thus contributed to the development of distinct archaeal communities in rhizospheres. Accordingly, for both plant species, the copy number ratios of AOA MnKat genes to amoA genes were significantly higher in rhizosphere soils than in bulk soils. In contrast to MnKat-negative strains from other AOA clades, the catalase activity of a representative isolate of "Ca. Nitrosocosmicus" was demonstrated. Members of this clade were enriched in H2O2-amended bulk soils, and constitutive expression of their MnKat gene was observed in both bulk and rhizosphere soils.

ConclusionsDue to their abundance, "Ca. Nitrosocosmicus" members can be considered key players mediating the nitrification process in rhizospheres. The selection of this MnKat-containing AOA in rhizospheres of several agriculturally important plants hints at a previously overlooked AOA-plant interaction. For additional mechanistic analyses of the interaction, this key clade of AOA with cultured representatives can be employed.
]]></description>
<dc:creator>Lee, U.-J.</dc:creator>
<dc:creator>Gwak, J.-H.</dc:creator>
<dc:creator>Choi, S.</dc:creator>
<dc:creator>Jung, M.-Y.</dc:creator>
<dc:creator>Lee, T. K.</dc:creator>
<dc:creator>Ryu, H.</dc:creator>
<dc:creator>Awala, S. I.</dc:creator>
<dc:creator>Wanek, W.</dc:creator>
<dc:creator>Wagner, M.</dc:creator>
<dc:creator>Quan, Z.-X.</dc:creator>
<dc:creator>Rhee, S.-K.</dc:creator>
<dc:date>2024-01-08</dc:date>
<dc:identifier>doi:10.1101/2024.01.08.574571</dc:identifier>
<dc:title><![CDATA[Candidatus Nitrosocosmicus members are the dominant archaea associated with pepper (Capsicum annuum L.) and ginseng (Panax ginseng C.A. Mey.) plants rhizospheres]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2024-01-08</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/2023.12.23.573102v1?rss=1">
<title>
<![CDATA[
Novel nitrifying symbiont lineages are vertically inherited and widespread in marine sponges 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/2023.12.23.573102v1?rss=1"
</link>
<description><![CDATA[
Ammonia-oxidising archaea and nitrite-oxidising bacteria are common members of marine sponge microbiomes. They derive energy for carbon fixation and growth from nitrification - the oxidation of ammonia to nitrite and further to nitrate - and are proposed to play essential roles in the carbon and nitrogen cycling of sponge holobionts. In this study, we characterise two novel nitrifying symbiont lineages,  Ca. Nitrosokoinonia and  Ca. Nitrosymbion in the marine sponge Coscinoderma matthewsi using a combination of molecular tools, single-cell imaging techniques, and physiological rate measurements. Both represent a new genus in the ammonia-oxidising archaeal class Nitrososphaeria and the nitrite-oxidising bacterial order Nitrospirales, respectively. Furthermore, we show that larvae of this viviparous sponge are densely colonised by representatives of  Ca. Nitrosokoinonia and  Ca. Nitrosymbion indicating vertical transmission. In adults, the representatives of both symbiont genera are located extracellularly in the mesohyl. Comparative metagenome analyses and physiological data suggest that ammonia-oxidising archaeal symbionts of the genus Ca. Nitrosokoinonia strongly rely on endogenously produced nitrogenous compounds (i.e., ammonium, urea, nitriles/cyanides, and creatinine) rather than on exogenous ammonium sources taken up by the sponge. Additionally, the nitrite-oxidising bacterial symbionts Ca. Nitrosymbion may reciprocally support the ammonia-oxidisers with ammonia via the utilisation of sponge-derived urea and cyanate. Interestingly, comparative analyses of published environmental 16S rRNA amplicon data revealed that  Ca. Nitrosokoinonia and  Ca. Nitrosymbion are widely distributed and predominantly associated with marine sponges and corals, suggesting a broad relevance of our findings.
]]></description>
<dc:creator>Glasl, B.</dc:creator>
<dc:creator>Luter, H. M.</dc:creator>
<dc:creator>Damjanovic, K.</dc:creator>
<dc:creator>Kitzinger, K.</dc:creator>
<dc:creator>Mueller, A. J.</dc:creator>
<dc:creator>Mahler, L.</dc:creator>
<dc:creator>Engelberts, J. P.</dc:creator>
<dc:creator>Rix, L.</dc:creator>
<dc:creator>Osvatic, J. T.</dc:creator>
<dc:creator>Hausmann, B.</dc:creator>
<dc:creator>Seneca, J.</dc:creator>
<dc:creator>Daims, H.</dc:creator>
<dc:creator>Pjevac, P.</dc:creator>
<dc:creator>Wagner, M.</dc:creator>
<dc:date>2023-12-23</dc:date>
<dc:identifier>doi:10.1101/2023.12.23.573102</dc:identifier>
<dc:title><![CDATA[Novel nitrifying symbiont lineages are vertically inherited and widespread in marine sponges]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2023-12-23</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/2023.11.20.567895v1?rss=1">
<title>
<![CDATA[
Characteristics of putative keystones in the healthy adult human gut microbiome as determined by correlation network analysis 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/2023.11.20.567895v1?rss=1"
</link>
<description><![CDATA[
Keystone species are thought to play a critical role in determining the structure and function of microbial communities. As they are important candidates for microbiome-targeted interventions, the identification and characterization of keystones is a pressing research goal. Both empirical as well as computational approaches to identify keystones have been proposed, and in particular correlation network analysis is frequently utilized to interrogate sequencing-based microbiome data. Here, we apply an established method for identifying putative keystone taxa in correlation networks. We develop a robust workflow for network construction and systematically evaluate the effects of taxonomic resolution on network properties and the identification of keystone taxa. We are able to identify correlation network keystone species and genera, but could not detect taxa with high keystone potential at lower taxonomic resolution. Based on the correlation patterns observed, we hypothesize that the identified putative keystone taxa have a stabilizing effect that is exerted on correlated taxa. Correlation network analysis further revealed subcommunities present in the dataset that are remarkably similar to previously described patterns. The interrogation of available metatranscriptomes also revealed distinct transcriptional states present in all putative keystone taxa.

IMPORTANCEThe work presented here contributes to the understanding of correlation network keystone taxa and sheds light on their potential ecological significance. By employing a robust workflow based on bootstrapping and subsampling techniques, we identify putative keystone species at the genus and species level. This emphasizes the importance of considering taxonomic resolution when investigating correlations. The potential impact of keystones on community stability provides valuable insights for systematic microbiome manipulation. Furthermore, the observed clusters of co-occurring taxa align well with recent findings and emphasize the reproducibility and relevance of the identified patterns in microbial community composition. We are able to add a functional dimension to the analysis with the identification of distinct transcriptional states in putative keystone taxa, highlighting their functional versatility and adaptability.
]]></description>
<dc:creator>Bauchinger, F.</dc:creator>
<dc:creator>Seki, D.</dc:creator>
<dc:creator>Berry, D.</dc:creator>
<dc:date>2023-11-21</dc:date>
<dc:identifier>doi:10.1101/2023.11.20.567895</dc:identifier>
<dc:title><![CDATA[Characteristics of putative keystones in the healthy adult human gut microbiome as determined by correlation network analysis]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2023-11-21</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/2023.11.19.567766v1?rss=1">
<title>
<![CDATA[
Chlamydiae in cnidarians: Shared functional potential despite broad taxonomic diversity 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/2023.11.19.567766v1?rss=1"
</link>
<description><![CDATA[
Cnidarians, such as corals and sea anemones, associate with a wide range of bacteria that have essential functions, including nutrient cycling and the production of antimicrobial compounds. Within cnidarians, bacteria can colonize all microhabitats including the tissues. Among them are obligate intracellular bacteria of the phylum Chlamydiota (chlamydiae) whose impact on cnidarian hosts and holobionts remain unknown. Here, we conducted a meta-analysis of previously published cnidarian 16S rRNA gene metabarcoding data and eight metagenome-assembled genomes (MAGs) of cnidarian-associated chlamydiae to decipher their diversity and functional potential. While the metabarcoding dataset showed an enormous diversity of cnidarian-associated chlamydiae, five out of eight MAGs were affiliated with the Simkaniaceae family. The other three MAGs were assigned to the Parasimkaniaceae, Rhabdochlamydiaceae, and Anoxychlamydiaceae, respectively. All MAGs were associated with corals and showed a functional potential insufficient for an independent existence, lacking any nucleotide or vitamin and most amino acid biosynthesis pathways. Hallmark chlamydial genes, such as a type III secretion system, nucleotide transporters, and genes for host interaction, were encoded in all MAGs. Together these observations suggest an obligate intracellular lifestyle of cnidarian-associated chlamydiae. Cnidarian-associated chlamydiae lacked unique genes, suggesting the core chlamydial genetic arsenal may be flexible enough to infect many eukaryotic hosts, including cnidarians. Additional studies are needed to understand how chlamydiae interact with their cnidarian host, and other microbes in cnidarian holobionts. This first study of the diversity and functional potential of cnidarian-associated chlamydiae improves our understanding of both the cnidarian microbiome and the chlamydial lifestyle and host range.
]]></description>
<dc:creator>Maire, J.</dc:creator>
<dc:creator>Collingro, A.</dc:creator>
<dc:creator>Horn, M.</dc:creator>
<dc:creator>van Oppen, M. J. H.</dc:creator>
<dc:date>2023-11-20</dc:date>
<dc:identifier>doi:10.1101/2023.11.19.567766</dc:identifier>
<dc:title><![CDATA[Chlamydiae in cnidarians: Shared functional potential despite broad taxonomic diversity]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2023-11-20</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/2023.11.12.566429v1?rss=1">
<title>
<![CDATA[
The Parkinson's drug entacapone disrupts gut microbiome homeostasis via iron sequestration 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/2023.11.12.566429v1?rss=1"
</link>
<description><![CDATA[
Increasing evidence shows that many human-targeted drugs alter the gut microbiome, leading to implications for host health. However, much less is known about the mechanisms by which drugs target the microbiome and how drugs affect microbial function. Here we combined quantitative microbiome profiling, long-read metagenomics, stable isotope probing and single cell chemical imaging to investigate the impact of two widely prescribed nervous system targeted drugs on the gut microbiome. Ex vivo supplementation of physiologically relevant concentrations of entacapone or loxapine succinate to faecal samples significantly impacted the abundance of up to one third of the microbial species present. Importantly, we demonstrate that the impact of these drugs on microbial metabolism is much more pronounced than their impact on abundances, with low concentrations of drugs reducing the activity, but not the abundance of key microbiome members like Bacteroides, Ruminococcus or Clostridium species. We further demonstrate that entacapone impacts the microbiome due to its ability to complex and deplete available iron, and that microbial growth can be rescued by replenishing levels of microbiota-accessible iron. Remarkably, entacapone-induced iron starvation selected for iron-scavenging organisms carrying antimicrobial resistance and virulence genes. Collectively, our study unveils the impact of two under-investigated drugs on whole microbiomes and identifies metal sequestration as a mechanism of drug-induced microbiome disturbance.
]]></description>
<dc:creator>Pereira, F. C.</dc:creator>
<dc:creator>Ge, X.</dc:creator>
<dc:creator>Kristensen, J. M.</dc:creator>
<dc:creator>Kirkegaard, R. H.</dc:creator>
<dc:creator>Maritsch, K.</dc:creator>
<dc:creator>Zu, Y.</dc:creator>
<dc:creator>Decorte, M.</dc:creator>
<dc:creator>Hausmann, B.</dc:creator>
<dc:creator>Berry, D.</dc:creator>
<dc:creator>Wasmund, K.</dc:creator>
<dc:creator>Schintlmeister, A.</dc:creator>
<dc:creator>Boettcher, T.</dc:creator>
<dc:creator>Cheng, J.-X.</dc:creator>
<dc:creator>Wagner, M.</dc:creator>
<dc:date>2023-11-12</dc:date>
<dc:identifier>doi:10.1101/2023.11.12.566429</dc:identifier>
<dc:title><![CDATA[The Parkinson's drug entacapone disrupts gut microbiome homeostasis via iron sequestration]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2023-11-12</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/2023.10.25.562895v1?rss=1">
<title>
<![CDATA[
Global abundance patterns, diversity, and ecology of Patescibacteria in wastewater treatment plants 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/2023.10.25.562895v1?rss=1"
</link>
<description><![CDATA[
BackgroundMicroorganisms are responsible for nutrient removal and resource recovery in wastewater treatment plants (WWTPs), and their diversity is often studied by 16S rRNA gene amplicon sequencing. However, this approach underestimates the abundance and diversity of Patescibacteria due to the low coverage of commonly used PCR primers for this highly divergent bacterial phylum. Therefore, our current understanding of the global diversity, distribution, and ecological role of Patescibacteria in WWTPs is very incomplete. This is particularly relevant as Patescibacteria are considered to be associated with microbial host cells and can therefore influence the abundance and temporal variability of other microbial groups that are important for WWTP functioning.

ResultsHere, we evaluated the in silico coverage of widely used 16S rRNA gene-targeted primer pairs and redesigned a primer pair targeting the V4 region of bacterial and archaeal 16S rRNA genes to expand its coverage for Patescibacteria. We then experimentally evaluated and compared the performance of the original and modified V4-targeted primers on 565 WWTP samples from the MiDAS global sample collection. Using the modified primer pair, the percentage of ASVs classified as Patescibacteria increased from 5.9% to 23.8%, and the number of detected patescibacterial genera increased from 560 to 1,576, while the detected diversity of the remaining microbial community remained similar. Due to this significantly improved coverage of Patescibacteria, we identified 23 core genera of Patescibacteria in WWTPs and described the global distribution pattern of these unusual microbes in these systems. Finally, correlation network analysis revealed potential host organisms that might be associated with Patescibacteria in WWTPs. Interestingly, strong indications were found for an association between Patescibacteria of the Saccharimonadia and globally abundant polyphosphate-accumulating organisms of the genus Ca. Phosporibacter.

ConclusionsOur study (i) provides an improved 16S rRNA gene V4 region-targeted amplicon primer pair inclusive of Patescibacteria with little impact on the detection of other taxa, (ii) reveals the diversity and distribution patterns of Patescibacteria in WWTPs on a global scale, and (iii) provides new insights into the ecological role and potential hosts of Patescibacteria in WWTPs.
]]></description>
<dc:creator>Wagner, M.</dc:creator>
<dc:creator>Hu, H.</dc:creator>
<dc:creator>Kristensen, J. M.</dc:creator>
<dc:creator>Pjevac, P.</dc:creator>
<dc:creator>Kitzinger, K.</dc:creator>
<dc:creator>Herbold, C. W.</dc:creator>
<dc:creator>Hausmann, B.</dc:creator>
<dc:creator>Dueholm, M. K. D.</dc:creator>
<dc:creator>Nielsen, P. H.</dc:creator>
<dc:date>2023-10-29</dc:date>
<dc:identifier>doi:10.1101/2023.10.25.562895</dc:identifier>
<dc:title><![CDATA[Global abundance patterns, diversity, and ecology of Patescibacteria in wastewater treatment plants]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2023-10-29</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/2023.10.23.563577v1?rss=1">
<title>
<![CDATA[
Soil fungi remain active and invest in storage compounds during drought independent of future climate conditions 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/2023.10.23.563577v1?rss=1"
</link>
<description><![CDATA[
Microbial growth is central to soil carbon cycling. However, how microbial communities grow under climate change is still largely unexplored. In an experiment simulating future climate conditions (increased atmospheric CO2 and temperature) and drought, we traced 2H or 18O applied via water-vapor exchange into fatty acids or DNA, respectively, allowing to measure community- and group-level adjustments in soil microbial physiology (replication, storage product synthesis, and carbon use efficiency, CUE). We show, that while overall community-level growth decreased by half during drought, fungal growth remained stable demonstrating an astonishing resistance of fungal activity against soil moisture changes. In addition, fungal investment into storage triglycerides increased more than five-fold under drought. CUE (the balance between anabolism and catabolism) was unaffected by drought but decreased in future climate conditions. Our results highlight that accounting for different growth strategies can foster our understanding of soil microbial contribution to C cycling and feedback to climate change.
]]></description>
<dc:creator>Canarini, A.</dc:creator>
<dc:creator>Fuchslueger, L.</dc:creator>
<dc:creator>Schnecker, J.</dc:creator>
<dc:creator>Metze, D.</dc:creator>
<dc:creator>Nelson, D.</dc:creator>
<dc:creator>Kahmen, A.</dc:creator>
<dc:creator>Watzka, M.</dc:creator>
<dc:creator>Poetsch, E. M.</dc:creator>
<dc:creator>Schaumberger, A.</dc:creator>
<dc:creator>Bahn, M.</dc:creator>
<dc:creator>Richter, A.</dc:creator>
<dc:date>2023-10-23</dc:date>
<dc:identifier>doi:10.1101/2023.10.23.563577</dc:identifier>
<dc:title><![CDATA[Soil fungi remain active and invest in storage compounds during drought independent of future climate conditions]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2023-10-23</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/2023.10.17.562718v1?rss=1">
<title>
<![CDATA[
Maximizing Efficiency in SedaDNA Analysis: A Novel Extract Pooling Approach 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/2023.10.17.562718v1?rss=1"
</link>
<description><![CDATA[
In recent years, the field of ancient DNA (aDNA) has taken a new direction toward studying human population dynamics through sedimentary DNA (sedaDNA), enabling the study of past ecosystems. However, the screening of numerous sediment samples from archaeological sites remains a time-consuming and costly endeavor, particularly when targeting hominin DNA. Here, we present a novel high-throughput method that facilitates the fast and efficient analysis of sediment samples by applying a pooled testing method. Our approach involves combining multiple extracts, allowing users to parallelize laboratory procedures early in the sample preparation pipeline while effectively screening for the presence of aDNA. Pooled samples that exhibit aDNA signals can then undergo detailed analysis, while empty pools are discarded. We have successfully applied our extract pooling method to various sediment samples from Middle and Upper Paleolithic sites in Europe, Asia, and Africa. Notably, our results reveal that an aDNA signal remains discernible even when pooled with four negative samples. We also demonstrate that the DNA yield of double-stranded libraries increases significantly when reducing the extract input, potentially mitigating the effects of inhibition. By embracing this innovative approach, researchers can analyze large numbers of sediment samples for aDNA preservation, achieving significant cost reductions of up to 70% and reducing hands-on laboratory time to one-fifth.
]]></description>
<dc:creator>Oberreiter, V.</dc:creator>
<dc:creator>Gelabert, P.</dc:creator>
<dc:creator>Brueck, F.</dc:creator>
<dc:creator>Franz, S.</dc:creator>
<dc:creator>Zelger, E.</dc:creator>
<dc:creator>Szedlacsek, S.</dc:creator>
<dc:creator>Cheronet, O.</dc:creator>
<dc:creator>Tenorio Cano, F.</dc:creator>
<dc:creator>Exler, F.</dc:creator>
<dc:creator>Zagorc, B.</dc:creator>
<dc:creator>Karavanic, I.</dc:creator>
<dc:creator>Banda, M.</dc:creator>
<dc:creator>Gasparyan, B.</dc:creator>
<dc:creator>Straus, L. G.</dc:creator>
<dc:creator>Gonzalez Morales, M. R.</dc:creator>
<dc:creator>Kappelman, J.</dc:creator>
<dc:creator>Stahlschmidt, M.</dc:creator>
<dc:creator>Rattei, T.</dc:creator>
<dc:creator>Kraemer, S. M.</dc:creator>
<dc:creator>Sawyer, S.</dc:creator>
<dc:creator>Pinhasi, R.</dc:creator>
<dc:date>2023-10-20</dc:date>
<dc:identifier>doi:10.1101/2023.10.17.562718</dc:identifier>
<dc:title><![CDATA[Maximizing Efficiency in SedaDNA Analysis: A Novel Extract Pooling Approach]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2023-10-20</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/2023.08.01.551195v1?rss=1">
<title>
<![CDATA[
Microclimate Shapes the Phylosymbiosis of Rodent Gut Microbiota in Jordan's Great Rift Valley 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/2023.08.01.551195v1?rss=1"
</link>
<description><![CDATA[
Host phylogeny and the environment play vital roles in shaping animal microbiomes. However, the effects of these variables on the diversity and richness of the gut microbiome in different bioclimatic zones remain underexplored. In this study, we investigated the effects of host phylogeny and bioclimatic zone on the diversity and composition of the gut microbiota of two heterospecific rodent species, the spiny mouse Acomys cahirinus and the house mouse Mus musculus, in three bioclimatic zones of the African Great Rift Valley (GRV). We confirmed host phylogeny using the D-loop sequencing method and analyzed the influence of host phylogeny and bioclimatic zone parameters on the rodent gut microbiome using high-throughput amplicon sequencing of 16S rRNA gene fragments. Phylogenetic analysis supported the morphological identification of the rodents and revealed a marked genetic difference between the two heterospecific species. We found that bioclimatic zone had a significant effect on the gut microbiota composition while host phylogeny did not. Microbial alpha diversity of heterospecific hosts was highest in the Mediterranean forest bioclimatic zone, followed by the Irano-Turranian shrubland, and was lowest in the Sudanian savanna tropical zone. The beta diversity of the two rodent species showed significant differences across the Mediterranean, Irano-Turranian, and Sudanian regions. The phyla Firmicutes and Bacteroidetes were highly abundant, and Deferribacterota, Cyanobacteria and Proteobacteria were also prominent. Amplicon sequence variants (ASVs) were identified that were unique to the Sudanian bioclimatic zone. The core microbiota families recovered in this study were consistent among heterospecific hosts. However, diversity decreased in conspecific host populations found at lower altitudes in Sudanian bioclimatic zone. The composition of the gut microbiota is linked to the adaptation of the host to its environment, and this study underscores the importance of incorporating climatic factors such as elevation and ambient temperature, in empirical microbiome research and is the first to describe the rodent gut microbiome from the GRV.
]]></description>
<dc:creator>Al-khlifeh, e. M.</dc:creator>
<dc:creator>Khadem, S.</dc:creator>
<dc:creator>Hausmann, B. M.</dc:creator>
<dc:creator>Berry, D.</dc:creator>
<dc:date>2023-08-01</dc:date>
<dc:identifier>doi:10.1101/2023.08.01.551195</dc:identifier>
<dc:title><![CDATA[Microclimate Shapes the Phylosymbiosis of Rodent Gut Microbiota in Jordan's Great Rift Valley]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2023-08-01</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/2023.03.27.534433v1?rss=1">
<title>
<![CDATA[
Evolution of an alternative genetic code in the Providencia symbiont of the haematophagous leech Haementeria acuecueyetzin 
]]>
</title>
<link>
https://biorxiv.org/cgi/content/short/2023.03.27.534433v1?rss=1"
</link>
<description><![CDATA[
Strict blood-feeding animals are confronted with a strong B vitamin deficiency. Blood-feeding leeches from the Glossiphoniidae family, similarly to haematophagous insects, have evolved specialised organs called bacteriomes to harbour symbiotic bacteria. Leeches of the Haementeria genus have two pairs of globular bacteriomes attached to the oesophagus which house intracellular Candidatus Providencia siddallii bacteria. Previous work analysing a draft genome of the Providencia symbiont of the Mexican leech Haementeria officinalis showed that, in this species, the bacteria hold a reduced genome capable of synthesising B vitamins. In this work, we aimed to expand our knowledge on the diversity and evolution of Providencia symbionts of Haementeria. For this purpose, we sequenced the symbiont genomes of three selected leech species. We found that all genomes are highly syntenic and have kept a stable genetic repertoire, mirroring ancient insect endosymbionts. Additionally, we found B vitamin pathways to be conserved among these symbionts, pointing to a conserved symbiotic role. Lastly and most notably, we found that the symbiont of Haementeria acuecueyetzin has evolved an alternative genetic code, affecting a portion of its proteome and showing evidence of a lineage-specific and likely intermediate stage of genetic code reassignment.
]]></description>
<dc:creator>Manzano-Marin, A.</dc:creator>
<dc:creator>Kvist, S.</dc:creator>
<dc:creator>Oceguera-Figueroa, A.</dc:creator>
<dc:date>2023-03-27</dc:date>
<dc:identifier>doi:10.1101/2023.03.27.534433</dc:identifier>
<dc:title><![CDATA[Evolution of an alternative genetic code in the Providencia symbiont of the haematophagous leech Haementeria acuecueyetzin]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2023-03-27</prism:publicationDate>
<prism:section></prism:section>
</item>
<item rdf:about="https://biorxiv.org/cgi/content/short/2022.08.28.505559v1?rss=1">
<title>
<![CDATA[
Co-obligate symbioses have repeatedly evolved across aphids, but partner identity and nutritional contributions vary across lineages 
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</title>
<link>
https://biorxiv.org/cgi/content/short/2022.08.28.505559v1?rss=1"
</link>
<description><![CDATA[
Aphids are a large family of phloem-sap feeders. They typically rely on a single bacterial endosymbiont, Buchnera aphidicola, to supply them with essential nutrients lacking in their diet. This association with Buchnera was described in model aphid species from the Aphidinae subfamily and has been assumed to be representative of most aphids. However, in two lineages, Buchnera has lost some essential symbiotic functions and is now complemented by additional symbionts. Though these cases break our view of aphids harbouring a single obligate endosymbiont, we know little about the extent, nature, and evolution of these associations across aphid subfamilies. Here, using metagenomics on 25 aphid species from nine subfamilies, re-assembly and re-annotation of 20 aphid symbionts previously sequenced, and 16S rRNA amplicon sequencing on 223 aphid samples (147 species from 12 subfamilies), we show that dual symbioses have evolved anew at least six times. We also show that these secondary co-obligate symbionts have typically evolved from facultative symbiotic taxa. Genome-based metabolic inference confirms interdependencies between Buchnera and its partners for the production of essential nutrients but shows contributions vary across pairs of co-obligate associates. Fluorescent in situ hybridisation microscopy shows a common bacteriocyte localisation of two newly acquired symbionts. Lastly, patterns of Buchnera genome evolution reveal that small losses affecting a few key genes can be the onset of these dual systems, while large gene losses can occur without any co-obligate symbiont acquisition. Hence, the Buchnera-aphid association, often thought of as exclusive, seems more flexible, with a few metabolic losses having recurrently promoted the establishment of a new co-obligate symbiotic partner.
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<dc:creator>Manzano-Marin, A.</dc:creator>
<dc:creator>Coeur d'acier, A.</dc:creator>
<dc:creator>Clamens, A.-L.</dc:creator>
<dc:creator>Cruaud, C.</dc:creator>
<dc:creator>Barbe, V.</dc:creator>
<dc:creator>Jousselin, E.</dc:creator>
<dc:date>2022-08-29</dc:date>
<dc:identifier>doi:10.1101/2022.08.28.505559</dc:identifier>
<dc:title><![CDATA[Co-obligate symbioses have repeatedly evolved across aphids, but partner identity and nutritional contributions vary across lineages]]></dc:title>
<dc:publisher>Cold Spring Harbor Laboratory Press</dc:publisher>
<prism:publicationDate>2022-08-29</prism:publicationDate>
<prism:section></prism:section>
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