ORCID Profile
0000-0003-4632-1187
Current Organisations
University of Queensland
,
University of Viennna
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Microbial Ecology | Microbial Genetics | Genomics | Bioinformatics | Population, Ecological and Evolutionary Genetics | Microbiology | Genetics
Expanding Knowledge in the Biological Sciences | Flora, Fauna and Biodiversity of environments not elsewhere classified | Ecosystem Assessment and Management of Marine Environments |
Publisher: Springer Science and Business Media LLC
Date: 20-04-2022
DOI: 10.1038/S41586-022-04614-3
Abstract: The capacity of planktonic marine microorganisms to actively seek out and exploit microscale chemical hotspots has been widely theorized to affect ocean-basin scale biogeochemistry
Publisher: Oxford University Press (OUP)
Date: 02-2009
DOI: 10.1111/J.1574-6941.2008.00628.X
Abstract: The giant marine ciliate Zoothamnium niveum (Ciliophora, Oligohymenophora) is obligatorily covered by a monolayer of putative chemoautotrophic sulfur-oxidizing (thiotrophic) bacteria. For Z. niveum specimens from the Caribbean Sea it has been demonstrated that this ectosymbiotic population consists of only a single pleomorphic phylotype described as Candidatus Thiobios zoothamnicoli. The goal of our study was to identify and phylogenetically analyse the ectosymbiont(s) of a recently discovered Z. niveum population from the Mediterranean Sea, and to compare marker genes encoding key enzymes of the carbon and sulfur metabolism between the two symbiont populations. We identified a single bacterial phylotype representing the ectosymbiont of Z. niveum from the Mediterranean population showing 99.7% 16S rRNA gene (99.2% intergenic spacer region) similarity to the Caribbean Z. niveum ectosymbiont. Genes encoding enzymes typical for an inorganic carbon metabolism [ribulose 1,5-bisphosphate carboxylase/oxygenase (RuBisCO)] and for sulfur metabolism (5'-adenylylsulfate reductase, dissimilatory sulfite reductase) were detected in both symbiotic populations. The very high amino acid sequence identity (97-100%) and the high nucleic acid sequence identity (90-98%) of these marker enzymes in two geographically distant symbiont populations suggests that the association of Z. niveum with Cand. Thiobios zoothamnicoli is very specific as well as temporally and spatially stable.
Publisher: Inter-Research Science Center
Date: 30-04-2009
DOI: 10.3354/MEPS07980
Publisher: American Association for Cancer Research (AACR)
Date: 04-04-2023
DOI: 10.1158/2159-8290.22541261
Abstract: Supplementary Data from IL27 Signaling Serves as an Immunologic Checkpoint for Innate Cytotoxic Cells to Promote Hepatocellular Carcinoma
Publisher: Cold Spring Harbor Laboratory
Date: 05-03-2020
DOI: 10.1101/2020.03.05.976373
Abstract: The evolution and ersification of Archaea is central to the history of life on Earth. Cultivation-independent approaches have revealed the existence of at least ten archaeal lineages whose members have small cell and genome sizes and limited metabolic capabilities and together comprise the tentative DPANN archaea. However, the phylogenetic ersity of DPANN and the placement of the various lineages of this group in the archaeal tree remain debated. Here, we reconstructed additional metagenome assembled genomes (MAGs) of a thus far uncharacterized archaeal phylum-level lineage UAP2 ( Candidatus Undinarchaeota) affiliating with DPANN archaea. Comparative genome analyses revealed that members of the Undinarchaeota have small estimated genome sizes and, while potentially being able to conserve energy through fermentation, likely depend on partner organisms for the acquisition of vitamins, amino acids and other metabolites. Phylogenomic analyses robustly recovered Undinarchaeota as a major independent lineage between two highly supported clans of DPANN: one clan comprising Micrarchaeota, Altiarchaeota and Diapherotrites, and another encompassing all other DPANN. Our analyses also suggest that DPANN archaea may have exchanged core genes with their hosts by horizontal gene transfer (HGT), adding to the difficulty of placing DPANN in the archaeal tree. Together, our findings provide crucial insights into the origins and evolution of DPANN archaea and their hosts.
Publisher: Springer Science and Business Media LLC
Date: 15-10-2019
DOI: 10.1038/S41396-018-0282-Y
Abstract: Marine Group II (MGII) archaea represent the most abundant planktonic archaeal group in ocean surface waters, but our understanding of the group has been limited by a lack of cultured representatives and few sequenced genomes. Here, we conducted a comparative phylogenomic analysis of 270 recently available MGII metagenome-assembled genomes (MAGs) to investigate their evolution and ecology. Based on a rank-normalised genome phylogeny, we propose that MGII is an order-level lineage for which we propose the name Candidatus Poseidoniale s (after Gr. n. Poseidon, God of the sea), comprising the families Candidatus Poseidonaceae fam. nov. (formerly subgroup MGIIa) and Candidatus Thalassarchaeaceae fam. nov. (formerly subgroup MGIIb). Within these families, 21 genera could be resolved, many of which had distinct biogeographic ranges and inferred nutrient preferences. Phylogenetic analyses of key metabolic functions suggest that the ancestor of Ca . Poseidoniales was a surface water-dwelling photoheterotroph that evolved to occupy multiple related ecological niches based primarily on spectral tuning of proteorhodopsin genes. Interestingly, this adaptation appears to involve an overwrite mechanism whereby an existing single copy of the proteorhodopsin gene is replaced by a horizontally transferred copy, which in many instances should allow an abrupt change in light absorption capacity. Phototrophy was lost entirely from five Ca . Poseidoniales genera coinciding with their adaptation to deeper aphotic waters. We also report the first instances of nitrate reductase in two genera acquired via horizontal gene transfer (HGT), which was a potential adaptation to oxygen limitation. Additional metabolic traits differentiating families and genera include flagellar-based adhesion, transporters, and sugar, amino acid, and peptide degradation. Our results suggest that HGT has shaped the evolution of Ca . Poseidoniales to occupy a variety of ecological niches and to become the most successful archaeal lineage in ocean surface waters.
Publisher: Springer Science and Business Media LLC
Date: 19-06-2015
Publisher: Springer Science and Business Media LLC
Date: 11-09-2017
DOI: 10.1038/S41564-017-0012-7
Abstract: Challenges in cultivating microorganisms have limited the phylogenetic ersity of currently available microbial genomes. This is being addressed by advances in sequencing throughput and computational techniques that allow for the cultivation-independent recovery of genomes from metagenomes. Here, we report the reconstruction of 7,903 bacterial and archaeal genomes from ,500 public metagenomes. All genomes are estimated to be ≥50% complete and nearly half are ≥90% complete with ≤5% contamination. These genomes increase the phylogenetic ersity of bacterial and archaeal genome trees by % and provide the first representatives of 17 bacterial and three archaeal candidate phyla. We also recovered 245 genomes from the Patescibacteria superphylum (also known as the Candidate Phyla Radiation) and find that the relative ersity of this group varies substantially with different protein marker sets. The scale and quality of this data set demonstrate that recovering genomes from metagenomes provides an expedient path forward to exploring microbial dark matter.
Publisher: Springer Science and Business Media LLC
Date: 28-08-2017
DOI: 10.1038/S41564-017-0010-9
Abstract: Microbial interactions influence the productivity and biogeochemistry of the ocean, yet they occur in miniscule volumes that cannot be s led by traditional oceanographic techniques. To investigate the behaviours of marine microorganisms at spatially relevant scales, we engineered an in situ chemotaxis assay (ISCA) based on microfluidic technology. Here, we describe the fabrication, testing and first field results of the ISCA, demonstrating its value in accessing the microbial behaviours that shape marine ecosystems.
Publisher: PeerJ
Date: 22-09-2016
DOI: 10.7717/PEERJ.2486
Abstract: High-throughput sequencing libraries are typically limited by the requirement for nanograms to micrograms of input DNA. This bottleneck impedes the microscale analysis of ecosystems and the exploration of low biomass s les. Current methods for lifying environmental DNA to bypass this bottleneck introduce considerable bias into metagenomic profiles. Here we describe and validate a simple modification of the Illumina Nextera XT DNA library preparation kit which allows creation of shotgun libraries from sub-nanogram amounts of input DNA. Community composition was reproducible down to 100 fg of input DNA based on analysis of a mock community comprising 54 phylogenetically erse Bacteria and Archaea. The main technical issues with the low input libraries were a greater potential for contamination, limited DNA complexity which has a direct effect on assembly and binning, and an associated higher percentage of read duplicates. We recommend a lower limit of 1 pg (∼100–1,000 microbial cells) to ensure community composition fidelity, and the inclusion of negative controls to identify reagent-specific contaminants. Applying the approach to marine surface water, pronounced differences were observed between bacterial community profiles of microliter volume s les, which we attribute to biological variation. This result is consistent with expected microscale patchiness in marine communities. We thus envision that our benchmarked, slightly modified low input DNA protocol will be beneficial for microscale and low biomass metagenomics.
Publisher: Springer Science and Business Media LLC
Date: 28-06-2021
DOI: 10.1038/S43705-021-00032-0
Abstract: Asgardarchaeota have been proposed as the closest living relatives to eukaryotes, and a total of 72 metagenome-assembled genomes (MAGs) representing six primary lineages in this archaeal phylum have thus far been described. These organisms are predicted to be fermentative heterotrophs contributing to carbon cycling in sediment ecosystems. Here, we double the genomic catalogue of Asgardarchaeota by obtaining 71 MAGs from a range of habitats around the globe, including the deep subsurface, brackish shallow lakes, and geothermal spring sediments. Phylogenomic inferences followed by taxonomic rank normalisation confirmed previously established Asgardarchaeota classes and revealed four additional lineages, two of which were consistently recovered as monophyletic classes. We therefore propose the names Candidatus Sifarchaeia class nov. and Ca . Jordarchaeia class nov., derived from the gods Sif and Jord in Norse mythology. Metabolic inference suggests that both classes represent hetero-organotrophic acetogens, which also have the ability to utilise methyl groups such as methylated amines, with acetate as the probable end product in remnants of a methanogen-derived core metabolism. This inferred mode of energy conservation is predicted to be enhanced by genetic code expansions, i.e., stop codon recoding, allowing the incorporation of the rare 21st and 22nd amino acids selenocysteine (Sec) and pyrrolysine (Pyl). We found Sec recoding in Jordarchaeia and all other Asgardarchaeota classes, which likely benefit from increased catalytic activities of Sec-containing enzymes. Pyl recoding, on the other hand, is restricted to Sifarchaeia in the Asgardarchaeota, making it the first reported non-methanogenic archaeal lineage with an inferred complete Pyl machinery, likely providing members of this class with an efficient mechanism for methylamine utilisation. Furthermore, we identified enzymes for the biosynthesis of ester-type lipids, characteristic of bacteria and eukaryotes, in both newly described classes, supporting the hypothesis that mixed ether-ester lipids are a shared feature among Asgardarchaeota.
Publisher: Wiley
Date: 13-03-2009
Publisher: Springer Science and Business Media LLC
Date: 15-11-2017
DOI: 10.1038/S41467-017-01376-9
Abstract: Microbial communities drive biogeochemical cycles through networks of metabolite exchange that are structured along energetic gradients. As energy yields become limiting, these networks favor co-metabolic interactions to maximize energy disequilibria. Here we apply single-cell genomics, metagenomics, and metatranscriptomics to study bacterial populations of the abundant “microbial dark matter” phylum Marinimicrobia along defined energy gradients. We show that evolutionary ersification of major Marinimicrobia clades appears to be closely related to energy yields, with increased co-metabolic interactions in more deeply branching clades. Several of these clades appear to participate in the biogeochemical cycling of sulfur and nitrogen, filling previously unassigned niches in the ocean. Notably, two Marinimicrobia clades, occupying different energetic niches, express nitrous oxide reductase, potentially acting as a global sink for the greenhouse gas nitrous oxide.
Publisher: Cold Spring Harbor Laboratory
Date: 03-03-2020
DOI: 10.1101/2020.03.01.972265
Abstract: An increasing wealth of genomic data from cultured and uncultured microorganisms provides the opportunity to develop a systematic taxonomy based on evolutionary relationships. Here we propose a standardized archaeal taxonomy, as part of the Genome Taxonomy Database (GTDB), derived from a 122 concatenated protein phylogeny that resolves polyphyletic groups and normalizes ranks based on relative evolutionary ergence (RED). The resulting archaeal taxonomy is stable under a range of phylogenetic variables, including marker genes, inference methods, corrections for rate heterogeneity and compositional bias, tree rooting scenarios, and expansion of the genome database. Rank normalization was shown to robustly correct for substitution rates varying up to 30-fold using simulated datasets. Taxonomic curation follows the rules of the International Code of Nomenclature of Prokaryotes (ICNP) while taking into account proposals to formally recognise the rank of phylum and to use genome sequences as type material. The taxonomy is based on 2,392 quality screened archaeal genomes, the great majority of which (93.3%) required one or more changes to their existing taxonomy, mostly as a result of incomplete classification. In total, 16 archaeal phyla are described, including reclassification of three major monophyletic units from the former Euryarchaeota and one phylum resulting from uniting the TACK superphylum into a single phylum. The taxonomy is publicly available at the GTDB website ( gtdb.ecogenomic.org ).
Publisher: Microbiology Society
Date: 09-06-2022
Abstract: Plastics are inexpensive and widely used organic polymers, but their high durability hinders biodegradation. Polystyrene, including extruded polystyrene (also known as styrofoam), is among the most commonly produced plastics worldwide and is recalcitrant to microbial degradation. In this study, we assessed changes in the gut microbiome of superworms ( Zophobas morio ) reared on bran, polystyrene or under starvation conditions over a 3 weeks period. Superworms on all diets were able to complete their life cycle to pupae and imago, although superworms reared on polystyrene had minimal weight gains, resulting in lower pupation rates compared to bran reared worms. The change in microbial gut communities from baseline differed considerably between diet groups, with polystyrene and starvation groups characterized by a loss of microbial ersity and the presence of opportunistic pathogens. Inferred microbial functions enriched in the polystyrene group included transposon movements, membrane restructuring and adaptations to oxidative stress. We detected several encoded enzymes with reported polystyrene and styrene degradation abilities, supporting previous reports of polystyrene-degrading bacteria in the superworm gut. By recovering metagenome-assembled genomes (MAGs) we linked phylogeny and functions and identified genera including Pseudomonas , Rhodococcus and Corynebacterium that possess genes associated with polystyrene degradation. In conclusion, our results provide the first metagenomic insights into the metabolic pathways used by the gut microbiome of superworms to degrade polystyrene. Our results also confirm that superworms can survive on polystyrene feed, but this diet has considerable negative impacts on host gut microbiome ersity and health.
Publisher: Cold Spring Harbor Laboratory
Date: 16-05-2022
DOI: 10.1101/2022.05.16.492041
Abstract: Plastics are inexpensive and widely used organic polymers, but their high durability hinders biodegradation. Polystyrene, including extruded polystyrene also known as styrofoam, is among the most commonly produced plastics worldwide and is recalcitrant to microbial degradation. In this study, we assessed changes in the gut microbiome of superworms ( Zophobas morio ) reared on bran, polystyrene, or under starvation conditions over a three weeks’ time period. Superworms on all diets were able to complete their life cycle to pupae and imago, although superworms reared on polystyrene had minimal weight gains, resulting in lower pupation rates. The change in microbial gut communities from baseline differed considerably between diet groups, with polystyrene and starvation groups characterized by a loss of microbial ersity and the presence of opportunistic pathogens. Inferred microbial functions enriched in the polystyrene group included transposon movements, membrane restructuring, and adaptations to oxidative stress. We detected several encoded enzymes with reported polystyrene and styrene degradation abilities, supporting previous reports of polystyrene degrading bacteria in the superworm gut. By recovering metagenome-assembled genomes (MAGs) we linked phylogeny and functions and identified genera including Pseudomonas, Rhodococcus and Corynebacterium , that possess genes associated with polystyrene degradation. In conclusion, our results provide the first metagenomic insights into the metabolic pathways used by the gut microbiome of superworms to degrade polystyrene. Our results also confirm that superworms can survive on polystyrene feed, however, this diet has considerable negative impacts on host gut microbiome ersity and health. Increasing plastic pollution is a major environmental problem, and a recently proposed way to counteract this trend is to embrace a circular economy, in which used materials are recycled, rather than disposed of. An important step to facilitate this process is to invent new approaches for upcycling of plastic waste to desirable consumer products. Microbial plastic degradation and conversion is likely to play a considerable part in shaping a circular economy, by engineering microbes or their enzymes to bio-upcycle plastic waste. A first step towards actualizing this goal is to identify microbes that can degrade polystyrene and to investigate the enzymes and pathways involved. Our study represents the first metagenomic analysis of an insect gut microbiome on a polystyrene diet. It identifies bacteria with polystyrene and styrene degrading abilities, and infers enzymes and pathways involved in these reactions. Therefore, our results contribute towards understanding microbial polystyrene degradation and will provide a base for future investigations into microbial upcycling of plastic waste.
Publisher: Springer Science and Business Media LLC
Date: 12-2016
Publisher: Springer Science and Business Media LLC
Date: 07-08-2020
DOI: 10.1038/S41467-020-17408-W
Abstract: The recently discovered DPANN archaea are a potentially deep-branching, monophyletic radiation of organisms with small cells and genomes. However, the monophyly and early emergence of the various DPANN clades and their role in life’s evolution are debated. Here, we reconstructed and analysed genomes of an uncharacterized archaeal phylum ( Candidatus Undinarchaeota), revealing that its members have small genomes and, while potentially being able to conserve energy through fermentation, likely depend on partner organisms for the acquisition of certain metabolites. Our phylogenomic analyses robustly place Undinarchaeota as an independent lineage between two highly supported ‘DPANN’ clans. Further, our analyses suggest that DPANN have exchanged core genes with their hosts, adding to the difficulty of placing DPANN in the tree of life. This pattern can be sufficiently dominant to allow identifying known symbiont-host clades based on routes of gene transfer. Together, our work provides insights into the origins and evolution of DPANN and their hosts.
Publisher: Springer Science and Business Media LLC
Date: 10-04-2014
Abstract: Single-cell genomics is a powerful tool for exploring the genetic makeup of environmental microorganisms, the vast majority of which are difficult, if not impossible, to cultivate with current approaches. Here we present a comprehensive protocol for obtaining genomes from uncultivated environmental microbes via high-throughput single-cell isolation by FACS. The protocol encompasses the preservation and pretreatment of differing environmental s les, followed by the physical separation, lysis, whole-genome lification and 16S rRNA-based identification of in idual bacterial and archaeal cells. The described procedure can be performed with standard molecular biology equipment and a FACS machine. It takes <12 h of bench time over a 4-d time period, and it generates up to 1 μg of genomic DNA from an in idual microbial cell, which is suitable for downstream applications such as PCR lification and shotgun sequencing. The completeness of the recovered genomes varies, with an average of ∼50%.
Publisher: Springer Science and Business Media LLC
Date: 27-04-2020
DOI: 10.1038/S41587-020-0501-8
Abstract: The Genome Taxonomy Database is a phylogenetically consistent, genome-based taxonomy that provides rank-normalized classifications for ~150,000 bacterial and archaeal genomes from domain to genus. However, almost 40% of the genomes in the Genome Taxonomy Database lack a species name. We address this limitation by using commonly accepted average nucleotide identity criteria to set bounds on species and propose species clusters that encompass all publicly available bacterial and archaeal genomes. Unlike previous average nucleotide identity studies, we chose a single representative genome to serve as the effective nomenclatural 'type' defining each species. Of the 24,706 proposed species clusters, 8,792 are based on published names. We assigned placeholder names to the remaining 15,914 species clusters to provide names to the growing number of genomes from uncultivated species. This resource provides a complete domain-to-species taxonomic framework for bacterial and archaeal genomes, which will facilitate research on uncultivated species and improve communication of scientific results.
Publisher: Springer Science and Business Media LLC
Date: 19-10-2022
Publisher: Public Library of Science (PLoS)
Date: 20-10-2011
Publisher: Springer Science and Business Media LLC
Date: 21-06-2021
DOI: 10.1038/S41564-021-00918-8
Abstract: The accrual of genomic data from both cultured and uncultured microorganisms provides new opportunities to develop systematic taxonomies based on evolutionary relationships. Previously, we established a bacterial taxonomy through the Genome Taxonomy Database. Here, we propose a standardized archaeal taxonomy that is derived from a 122-concatenated-protein phylogeny that resolves polyphyletic groups and normalizes ranks based on relative evolutionary ergence. The resulting archaeal taxonomy, which forms part of the Genome Taxonomy Database, is stable for a range of phylogenetic variables including marker gene selection, inference methods, corrections for rate heterogeneity and compositional bias, tree rooting scenarios and expansion of the genome database. Rank normalization is shown to robustly correct for substitution rates varying up to 30-fold using simulated datasets. Taxonomic curation follows the rules of the International Code of Nomenclature of Prokaryotes while taking into account proposals to formally recognize the rank of phylum and to use genome sequences as type material. This taxonomy is based on 2,392 archaeal genomes, 93.3% of which required one or more changes to their existing taxonomy, mainly owing to incomplete classification. We identify 16 archaeal phyla and reclassify 3 major monophyletic units from the former Euryarchaeota and one phylum that unites the Thaumarchaeota-Aigarchaeota-Crenarchaeota-Korarchaeota (TACK) superphylum into a single phylum.
Publisher: Springer Science and Business Media LLC
Date: 08-2014
Publisher: Frontiers Media SA
Date: 21-01-2022
Publisher: Frontiers Media SA
Date: 18-04-2018
Publisher: Springer Science and Business Media LLC
Date: 08-2017
DOI: 10.1038/NBT.3893
Abstract: We present two standards developed by the Genomic Standards Consortium (GSC) for reporting bacterial and archaeal genome sequences. Both are extensions of the Minimum Information about Any (x) Sequence (MIxS). The standards are the Minimum Information about a Single Amplified Genome (MISAG) and the Minimum Information about a Metagenome-Assembled Genome (MIMAG), including, but not limited to, assembly quality, and estimates of genome completeness and contamination. These standards can be used in combination with other GSC checklists, including the Minimum Information about a Genome Sequence (MIGS), Minimum Information about a Metagenomic Sequence (MIMS), and Minimum Information about a Marker Gene Sequence (MIMARKS). Community-wide adoption of MISAG and MIMAG will facilitate more robust comparative genomic analyses of bacterial and archaeal ersity.
Publisher: Springer Science and Business Media LLC
Date: 27-08-2018
DOI: 10.1038/NBT.4229
Abstract: Taxonomy is an organizing principle of biology and is ideally based on evolutionary relationships among organisms. Development of a robust bacterial taxonomy has been hindered by an inability to obtain most bacteria in pure culture and, to a lesser extent, by the historical use of phenotypes to guide classification. Culture-independent sequencing technologies have matured sufficiently that a comprehensive genome-based taxonomy is now possible. We used a concatenated protein phylogeny as the basis for a bacterial taxonomy that conservatively removes polyphyletic groups and normalizes taxonomic ranks on the basis of relative evolutionary ergence. Under this approach, 58% of the 94,759 genomes comprising the Genome Taxonomy Database had changes to their existing taxonomy. This result includes the description of 99 phyla, including six major monophyletic units from the sub ision of the Proteobacteria, and amalgamation of the Candidate Phyla Radiation into a single phylum. Our taxonomy should enable improved classification of uncultured bacteria and provide a sound basis for ecological and evolutionary studies.
Publisher: American Association for Cancer Research (AACR)
Date: 04-04-2023
DOI: 10.1158/2159-8290.C.6549593
Abstract: Abstract Although inflammatory mechanisms driving hepatocellular carcinoma (HCC) have been proposed, the regulators of anticancer immunity in HCC remain poorly understood. We found that IL27 receptor (IL27R) signaling promotes HCC development i in vivo /i . High IL27EBI3 cytokine or i IL27RA /i expression correlated with poor prognosis for patients with HCC. Loss of IL27R suppressed HCC i in vivo /i in two different models of hepatocarcinogenesis. Mechanistically, IL27R signaling within the tumor microenvironment restrains the cytotoxicity of innate cytotoxic lymphocytes. IL27R ablation enhanced their accumulation and activation, whereas depletion or functional impairment of innate cytotoxic cells abrogated the effect of IL27R disruption. Pharmacologic neutralization of IL27 signaling increased infiltration of innate cytotoxic lymphocytes with upregulated cytotoxic molecules and reduced HCC development. Our data reveal an unexpected role of IL27R signaling as an immunologic checkpoint regulating innate cytotoxic lymphocytes and promoting HCC of different etiologies, thus indicating a therapeutic potential for IL27 pathway blockade in HCC. Significance: HCC, the most common form of liver cancer, is characterized by a poor survival rate and limited treatment options. The discovery of a novel IL27-dependent mechanism controlling anticancer cytotoxic immune response will pave the road for new treatment options for this devastating disease. i a href="ancerdiscovery/article/doi/10.1158/2159-8290.CD-12-8-ITI" target="_blank" This article is highlighted in the In This Issue feature, p. 1825 /a /i /
Publisher: Cold Spring Harbor Laboratory
Date: 19-02-2021
DOI: 10.1101/2021.02.19.431964
Abstract: Asgardarchaeota have been proposed as the closest living relatives to eukaryotes, and a total of 72 metagenome-assembled genomes (MAGs) representing six primary lineages in this archaeal phylum have thus far been described. These organisms are predicted to be fermentative organoheterotrophs contributing to carbon cycling in sediment ecosystems. Here, we double the genomic catalogue of Asgardarchaeota by obtaining 71 MAGs from a range of habitats around the globe, including deep subsurface, shallow lake, and geothermal spring sediments. Phylogenomic inferences followed by taxonomic rank normalisation confirmed previously established Asgardarchaeota classes and revealed four novel lineages, two of which were consistently recovered as monophyletic classes. We therefore propose the names Candidatus Hodarchaeia class nov. and Cand. Jordarchaeia class nov., derived from the gods Hod and Jord in Norse mythology. Metabolic inference suggests that both novel classes represent methylotrophic acetogens, encoding the transfer of methyl groups, such as methylated amines, to coenzyme M with acetate as the end product in remnants of a methanogen-derived core metabolism. This inferred mode of energy conservation is predicted to be enhanced by genetic code expansions, i.e. recoding, allowing the incorporation of the rare 21st and 22nd amino acids selenocysteine (Sec) and pyrrolysine (Pyl). We found Sec recoding in Jordarchaeia and all other Asgardarchaeota classes, which likely benefit from increased catalytic activities of Sec-containing enzymes. Pyl recoding on the other hand is restricted to Hodarchaeia in the Asgardarchaeota, making it the first reported non-methanogenic lineage with an inferred complete Pyl machinery, likely providing this class with an efficient mechanism for methylamine utilisation. Furthermore, we identified enzymes for the biosynthesis of ester-type lipids, characteristic of Bacteria and Eukaryotes, in both novel classes, supporting the hypothesis that mixed ether-ester lipids are a shared feature among Asgardarchaeota.
Publisher: American Association for Cancer Research (AACR)
Date: 04-04-2023
DOI: 10.1158/2159-8290.22541261.V1
Abstract: Supplementary Data from IL27 Signaling Serves as an Immunologic Checkpoint for Innate Cytotoxic Cells to Promote Hepatocellular Carcinoma
Publisher: Cold Spring Harbor Laboratory
Date: 30-07-2021
DOI: 10.1101/2021.07.29.453957
Abstract: Asgardarchaeota encode many eukaryotic signature proteins and are widely considered to represent the closest archaeal relatives of eukaryotes. Whether similarities between Asgard archaea and eukaryotes extend to their viromes remains unknown. Here we present 20 metagenome-assembled genomes of Asgardarchaeota from deep-sea sediments of the basin off the Shimokita Peninsula, Japan. By combining CRISPR spacer search of metagenomic sequences with phylogenomic analysis, we identify three family-level groups of viruses associated with Asgard archaea. The first group, Verdan iruses, includes tailed viruses of the realm Duplodnaviria , the second one, Skuldviruses, consists of viruses with predicted icosahedral capsids that belong to the realm Varidnaviria , and the third group, Wyrdviruses, is related to spindle-shaped viruses previously identified in other archaea. More than 90% of the proteins encoded by these putative viruses of Asgard archaea show no sequence similarity to proteins encoded by other known viruses. Nevertheless, all three proposed families consist of viruses typical of prokaryotes, providing no indication of a specific evolutionary relationship between viruses infecting Asgard archaea and eukaryotes. Verdan iruses and skuldviruses are likely to be lytic, whereas wyrdviruses, similar to all other known spindle-shaped viruses, probably establish chronic infection and are released without host cell lysis. All three groups of viruses were identified in sediment s les from distinct geographical locations and are expected to play important roles in controlling the Asgard archaea populations in deep-sea ecosystems.
Publisher: Oxford University Press (OUP)
Date: 2023
Abstract: The Genome Taxonomy Database (GTDB) is a taxonomic framework that defines prokaryotic taxa as monophyletic groups in concatenated protein reference trees according to systematic criteria. This has resulted in a substantial number of changes to existing classifications (gtdb.ecogenomic.org). In the case of union of taxa, GTDB names were applied based on the priority of publication. The ision of taxa or change in rank led to the formation of new Latin names above the rank of genus that were only made publicly available via the GTDB website without associated published taxonomic descriptions. This has sometimes led to confusion in the literature and databases. A number of the provisional GTDB names were later published in other studies, while many still lack authorships. To reduce further confusion, here we propose names and descriptions for 329 GTDB-defined prokaryotic taxa, 223 of which are suitable for validation under the International Code of Nomenclature of Prokaryotes (ICNP) and 49 under the Code of Nomenclature of Prokaryotes described from Sequence Data (SeqCode). For the latter, we designated 23 genomes as type material. An additional 57 taxa that do not currently satisfy the validation criteria of either code are proposed as Candidatus.
Publisher: Springer Science and Business Media LLC
Date: 02-2009
DOI: 10.1007/BF03179969
Publisher: Springer Science and Business Media LLC
Date: 12-08-2014
DOI: 10.1007/S00792-014-0664-7
Abstract: Despite >130 years of microbial cultivation studies, many microorganisms remain resistant to traditional cultivation approaches, including numerous candidate phyla of bacteria and archaea. Unraveling the mysteries of these candidate phyla is a grand challenge in microbiology and is especially important in habitats where they are abundant, including some extreme environments and low-energy ecosystems. Over the past decade, parallel advances in DNA lification, DNA sequencing and computing have enabled rapid progress on this problem, particularly through metagenomics and single-cell genomics. Although each approach suffers limitations, metagenomics and single-cell genomics are particularly powerful when combined synergistically. Studies focused on extreme environments have revealed the first substantial genomic information for several candidate phyla, encompassing putative acidophiles (Parvarchaeota), halophiles (Nanohaloarchaeota), thermophiles (Acetothermia, Aigarchaeota, Atribacteria, Calescamantes, Korarchaeota, and Fervidibacteria), and piezophiles (Gracilibacteria). These data have enabled insights into the biology of these organisms, including catabolic and anabolic potential, molecular adaptations to life in extreme environments, unique genomic features such as stop codon reassignments, and predictions about cell ultrastructure. In addition, the rapid expansion of genomic coverage enabled by these studies continues to yield insights into the early ersification of microbial lineages and the relationships within and between the phyla of Bacteria and Archaea. In the next 5 years, the genomic foliage within the tree of life will continue to grow and the study of yet-uncultivated candidate phyla will firmly transition into the post-genomic era.
Publisher: The Royal Society
Date: 27-07-2007
Abstract: Zoothamnium niveum (Ciliophora, Oligohymenophora) is a giant, colonial marine ciliate from sulphide-rich, shallow-water habitats, obligatorily associated with the ectosymbiotic, chemoautotrophic, sulphide-oxidizing bacterium ‘ Candidatus Thiobios zoothamnicoli’. The aims of this study were to characterize the natural habitat and investigate growth, reproduction, survival and maintenance of the symbiosis from Corsica , France (Mediterranean Sea) using a flow-through respirometer providing stable chemical conditions. We were able to successfully cultivate the Z. niveum symbiosis during its entire lifespan and document reproduction, whereby the optimum conditions were found to range from 3 to 33 μmol l −1 ΣH 2 S in normoxic seawater. Starting with an inoculum of 13 specimens, we found up to 173 new specimens that were asexually produced after only 11 days. Observed mean lifespan of the Z. niveum colonies was approximately 11 days and mean colony size reached 51 branches, from which rapid host ision rates of up to every 4.1 hours were calculated. Comparing the ectosymbiotic population from Z. niveum colonies collected from their natural habitat with those cultivated under optimal conditions, we found significant differences in the bacterial morphology and the frequency of iding cells on distinct host parts, which is most likely caused by behaviour of the host ciliate. Applying different sulphide concentrations we revealed that the symbiosis was not able to survive without sulphide and was harmed by high sulphide conditions. To our knowledge, this study reports the first successful cultivation of a thiotrophic ectosymbiosis.
Publisher: American Association for Cancer Research (AACR)
Date: 04-04-2023
DOI: 10.1158/2159-8290.C.6549593.V1
Abstract: Abstract Although inflammatory mechanisms driving hepatocellular carcinoma (HCC) have been proposed, the regulators of anticancer immunity in HCC remain poorly understood. We found that IL27 receptor (IL27R) signaling promotes HCC development i in vivo /i . High IL27EBI3 cytokine or i IL27RA /i expression correlated with poor prognosis for patients with HCC. Loss of IL27R suppressed HCC i in vivo /i in two different models of hepatocarcinogenesis. Mechanistically, IL27R signaling within the tumor microenvironment restrains the cytotoxicity of innate cytotoxic lymphocytes. IL27R ablation enhanced their accumulation and activation, whereas depletion or functional impairment of innate cytotoxic cells abrogated the effect of IL27R disruption. Pharmacologic neutralization of IL27 signaling increased infiltration of innate cytotoxic lymphocytes with upregulated cytotoxic molecules and reduced HCC development. Our data reveal an unexpected role of IL27R signaling as an immunologic checkpoint regulating innate cytotoxic lymphocytes and promoting HCC of different etiologies, thus indicating a therapeutic potential for IL27 pathway blockade in HCC. Significance: HCC, the most common form of liver cancer, is characterized by a poor survival rate and limited treatment options. The discovery of a novel IL27-dependent mechanism controlling anticancer cytotoxic immune response will pave the road for new treatment options for this devastating disease. i a href="ancerdiscovery/article/doi/10.1158/2159-8290.CD-12-8-ITI" target="_blank" This article is highlighted in the In This Issue feature, p. 1825 /a /i /
Publisher: Public Library of Science (PLoS)
Date: 03-06-2015
Publisher: Frontiers Media SA
Date: 24-04-2017
Publisher: Springer Science and Business Media LLC
Date: 27-06-2022
DOI: 10.1038/S41564-022-01144-6
Abstract: Asgardarchaeota harbour many eukaryotic signature proteins and are widely considered to represent the closest archaeal relatives of eukaryotes. Whether similarities between Asgard archaea and eukaryotes extend to their viromes remains unknown. Here we present 20 metagenome-assembled genomes of Asgardarchaeota from deep-sea sediments of the basin off the Shimokita Peninsula, Japan. By combining a CRISPR spacer search of metagenomic sequences with phylogenomic analysis, we identify three family-level groups of viruses associated with Asgard archaea. The first group, verdan iruses, includes tailed viruses of the class Caudoviricetes (realm Duplodnaviria) the second, skuldviruses, consists of viruses with predicted icosahedral capsids of the realm Varidnaviria and the third group, wyrdviruses, is related to spindle-shaped viruses previously identified in other archaea. More than 90% of the proteins encoded by these viruses of Asgard archaea show no sequence similarity to proteins encoded by other known viruses. Nevertheless, all three proposed families consist of viruses typical of prokaryotes, providing no indication of specific evolutionary relationships between viruses infecting Asgard archaea and eukaryotes. Verdan iruses and skuldviruses are likely to be lytic, whereas wyrdviruses potentially establish chronic infection and are released without host cell lysis. All three groups of viruses are predicted to play important roles in controlling Asgard archaea populations in deep-sea ecosystems.
Publisher: Springer Science and Business Media LLC
Date: 05-08-2019
DOI: 10.1038/S41564-019-0526-2
Abstract: Viral discovery is accelerating at an unprecedented rate due to continuing advances in culture-independent sequence-based analyses. One important facet of this discovery is identification of the hosts of these recently characterized uncultured viruses. To this end, we have adapted the viral tagging approach, which bypasses the need for culture-based methods to identify host-phage pairings. Fluorescently labelled anonymous virions adsorb to unlabelled anonymous bacterial host cells, which are then in idually sorted as host-phage pairs, followed by genome lification and high-throughput sequencing to establish the identities of both the host and the attached virus(es). We demonstrate single-cell viral tagging using the faecal microbiome, including cross-tagging of viruses and bacteria between human subjects. A total of 363 unique host-phage pairings were predicted, most of which were subject-specific and involved previously uncharacterized viruses despite the majority of their bacterial hosts having known taxonomy. One-fifth of these pairs were confirmed by multiple in idual tagged cells. Viruses targeting more than one bacterial species were conspicuously absent in the host-phage network, suggesting that phages are not major vectors of inter-species horizontal gene transfer in the human gut. A high level of cross-reactivity between phages and bacteria from different subjects was noted despite subject-specific viral profiles, which has implications for faecal microbiota transplant therapy.
Publisher: American Association for Cancer Research (AACR)
Date: 20-06-2022
DOI: 10.1158/2159-8290.CD-20-1628
Abstract: HCC, the most common form of liver cancer, is characterized by a poor survival rate and limited treatment options. The discovery of a novel IL27-dependent mechanism controlling anticancer cytotoxic immune response will pave the road for new treatment options for this devastating disease. This article is highlighted in the In This Issue feature, p. 1825
Publisher: Wiley
Date: 07-2009
Publisher: Springer Science and Business Media LLC
Date: 17-12-2021
DOI: 10.1038/S43705-021-00079-Z
Abstract: Investigating the composition and metabolic capacity of aquatic microbial assemblages usually requires the filtration of multi-litre s les, which are up to 1 million-fold larger than the microenvironments within which microbes are predicted to be spatially organised. To determine if community profiles can be reliably generated from microlitre volumes, we s led seawater at a coastal and an oceanic site, filtered and homogenised them, and extracted DNA from bulk s les (2 L) and microvolumes (100, 10 and 1 μL) using two new approaches. These microvolume DNA extraction methods involve either physical or chemical lysis (through pH/thermal shock and lytic enzymes/surfactants, respectively), directly followed by the capture of DNA on magnetic beads. Downstream analysis of extracted DNA using both licon sequencing and metagenomics, revealed strong correlation with standard large volume approaches, demonstrating the fidelity of taxonomic and functional profiles of microbial communities in as little as 1 μL of seawater. This volume is six orders of magnitude smaller than most standard operating procedures for marine metagenomics, which will allow precise s ling of the heterogenous landscape that microbes inhabit.
Publisher: Springer Science and Business Media LLC
Date: 24-01-2022
Publisher: Springer Science and Business Media LLC
Date: 23-01-2015
Publisher: Frontiers Media SA
Date: 08-01-2015
Publisher: Springer Science and Business Media LLC
Date: 04-05-2020
Publisher: Springer New York
Date: 2018
DOI: 10.1007/978-1-4939-8728-3_7
Abstract: Single-cell genomics allows bypassing the culturing step and to directly access environmental microbes one cell at a time. The method has been successfully applied to explore archaeal and bacterial candidate phyla, referred to as microbial dark matter. Here I summarize the single-cell genomics workflow, including s le preparation and preservation, high-throughput fluorescence-activated cell sorting, cell lysis and lification of environmental s les. Furthermore I describe phylogenetic screening based on 16S rRNA genes and suggest a suitable library preparation and sequencing approach.
Publisher: Springer Science and Business Media LLC
Date: 29-01-2014
DOI: 10.1038/NATURE12959
Abstract: Cultivated bacteria such as actinomycetes are a highly useful source of biomedically important natural products. However, such 'talented' producers represent only a minute fraction of the entire, mostly uncultivated, prokaryotic ersity. The uncultured majority is generally perceived as a large, untapped resource of new drug candidates, but so far it is unknown whether taxa containing talented bacteria indeed exist. Here we report the single-cell- and metagenomics-based discovery of such producers. Two phylotypes of the candidate genus 'Entotheonella' with genomes of greater than 9 megabases and multiple, distinct biosynthetic gene clusters co-inhabit the chemically and microbially rich marine sponge Theonella swinhoei. Almost all bioactive polyketides and peptides known from this animal were attributed to a single phylotype. 'Entotheonella' spp. are widely distributed in sponges and belong to an environmental taxon proposed here as candidate phylum 'Tectomicrobia'. The pronounced bioactivities and chemical uniqueness of 'Entotheonella' compounds provide significant opportunities for ecological studies and drug discovery.
Publisher: Elsevier BV
Date: 2019
DOI: 10.1016/J.SYAPM.2018.07.003
Abstract: Naming of uncultured Bacteria and Archaea is often inconsistent with the International Code of Nomenclature of Prokaryotes. The recent practice of proposing names for higher taxa without designation of lower ranks and nomenclature types is one of the most important inconsistencies that needs to be addressed to avoid nomenclatural instability. The Code requires names of higher taxa up to the rank of class to be derived from the type genus name, with a proposal pending to formalise this requirement for the rank of phylum. Designation of nomenclature types is crucial for providing priority to names and ensures their uniqueness and stability. However, only legitimate names proposed for axenic cultures can be used for this purpose. Candidatus names reserved for taxa lacking cultured representatives may be granted this right if recent proposals to use genome sequences as type material are endorsed, thereby allowing the Code to be fully applied to lineages represented by metagenome-assembled genomes (MAGs) or single lified genomes (SAGs). Genome quality standards need to be considered to ensure unambiguous assignment of type material. Here, we illustrate the recommended practice by proposing nomenclature type material for four major uncultured prokaryotic lineages based on high-quality MAGs in accordance with the Code.
Publisher: Springer Science and Business Media LLC
Date: 14-07-2013
DOI: 10.1038/NATURE12352
Abstract: Genome sequencing enhances our understanding of the biological world by providing blueprints for the evolutionary and functional ersity that shapes the biosphere. However, microbial genomes that are currently available are of limited phylogenetic breadth, owing to our historical inability to cultivate most microorganisms in the laboratory. We apply single-cell genomics to target and sequence 201 uncultivated archaeal and bacterial cells from nine erse habitats belonging to 29 major mostly uncharted branches of the tree of life, so-called 'microbial dark matter'. With this additional genomic information, we are able to resolve many intra- and inter-phylum-level relationships and to propose two new superphyla. We uncover unexpected metabolic features that extend our understanding of biology and challenge established boundaries between the three domains of life. These include a novel amino acid use for the opal stop codon, an archaeal-type purine synthesis in Bacteria and complete sigma factors in Archaea similar to those in Bacteria. The single-cell genomes also served to phylogenetically anchor up to 20% of metagenomic reads in some habitats, facilitating organism-level interpretation of ecosystem function. This study greatly expands the genomic representation of the tree of life and provides a systematic step towards a better understanding of biological evolution on our planet.
Publisher: Springer Science and Business Media LLC
Date: 21-11-2020
Start Date: 2018
End Date: 2020
Funder: Australian Research Council
View Funded ActivityStart Date: 2016
End Date: 2018
Funder: Australian Research Council
View Funded ActivityStart Date: 2017
End Date: 2020
Funder: Australian Research Council
View Funded ActivityStart Date: 04-2018
End Date: 02-2024
Amount: $466,358.00
Funder: Australian Research Council
View Funded ActivityStart Date: 12-2017
End Date: 12-2022
Amount: $728,776.00
Funder: Australian Research Council
View Funded Activity