Project description:Within the gut microbiome, Methanobrevibacter and Methanosphaera species are the prevailing methanogenic archaea. In general, these archaeal species interact widely with other members of the gut microbiome, subsequently facilitating the processes of digestion and fermentation within humans, thereby playing a significant role in the gut. Despite their significance, detailed characteristics and microbiome-host interactions remain largely unexplored. One potential mechanism for microbiome-host interaction and communication involves extracellular vesicles, which play a crucial role in both inter- and intra-kingdom interactions as well as intercellular communication. The production of extracellular vesicles has been confirmed for representatives of all three domains of life, eukaryotes, bacteria, and archaea. In this study, we report for the first time that human gut-derived archaea are capable of producing extracellular vesicles. Here, we present the ultrastructure, composition, proteome, and metabolome of these newly discovered archaeal extracellular vesicles (AEV) of M. smithii (strains ALI and GRAZ-2), Candidatus M. intestini, and Methanosphaera stadtmanae. Here, we describe their morphology, contents of archaeal extracellular vesicles (AEV) produced by the major methanogenic archaea of the human gut, namely Methanobrevibacter smithii (strains ALI and GRAZ-2), Candidatus M. intestini, and Methanosphaera stadtmanae. We also describe their interaction with human cell lines and ability to trigger immune responses. The findings show a high similarity of AEVs to their bacterial counterparts in size, morphology, and composition. Proteome and metabolome analysis demonstrate high similarities between vesicles derived from Methanobrevibacter species and are highly enriched in adhesin or adhesin-like proteins, suggesting an important role for archaeal-bacterial and archaeal-host interactions. Unless the specific role of AEVs could not be identified, their production itself suggests an intricate network of interdomain interactions shaping the dynamics of the human microbiome.
Project description:Methanococcus maripaludis is a methanogenic archaeon. Within its genome, there are two operons for membrane associated hydrogenases, eha and ehb. To investigate the regulation of ehb on the cell, an S40 mutant was constructed in such a way that a portion of the ehb operon was replaced by pac cassette in the wild type parental strain S2 (done by Whitman's group at the University of Georgia). Four samples of each strain were grown in batch culture. Differences in transcriptional expression between S40 and S2 were measured using cDNA arrays, with flip dye experiments for each biological replicate. Keywords: mutant, archaea, carbon, hydrogenase, methanogen
Project description:Benedict2011 - Genome-scale metoblic network
of Methanosarcina acetivorans (iMB745)
This model is described in the article:
Genome-scale metabolic
reconstruction and hypothesis testing in the methanogenic
archaeon Methanosarcina acetivorans C2A.
Benedict MN, Gonnerman MC, Metcalf
WW, Price ND.
J. Bacteriol. 2012 Feb; 194(4):
855-865
Abstract:
Methanosarcina acetivorans strain C2A is a marine
methanogenic archaeon notable for its substrate utilization,
genetic tractability, and novel energy conservation mechanisms.
To help probe the phenotypic implications of this organism's
unique metabolism, we have constructed and manually curated a
genome-scale metabolic model of M. acetivorans, iMB745, which
accounts for 745 of the 4,540 predicted protein-coding genes
(16%) in the M. acetivorans genome. The reconstruction effort
has identified key knowledge gaps and differences in peripheral
and central metabolism between methanogenic species. Using flux
balance analysis, the model quantitatively predicts wild-type
phenotypes and is 96% accurate in knockout lethality
predictions compared to currently available experimental data.
The model was used to probe the mechanisms and energetics of
by-product formation and growth on carbon monoxide, as well as
the nature of the reaction catalyzed by the soluble
heterodisulfide reductase HdrABC in M. acetivorans. The
genome-scale model provides quantitative and qualitative
hypotheses that can be used to help iteratively guide
additional experiments to further the state of knowledge about
methanogenesis.
This model is hosted on
BioModels Database
and identified by:
MODEL1507180040.
To cite BioModels Database, please use:
BioModels Database:
An enhanced, curated and annotated resource for published
quantitative kinetic models.
To the extent possible under law, all copyright and related or
neighbouring rights to this encoded model have been dedicated to
the public domain worldwide. Please refer to
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Project description:Histones are a principal constituent of chromatin in eukaryotes and fundamental to our understanding of eukaryotic gene regulation. In archaea, histones are phylogenetically widespread but not universal: several archaeal lineages have independently lost histone genes. What prompted or facilitated these losses and how archaea without histones organize their chromatin remains largely unknown. Here, we use micrococcal nuclease digestion of native and reconstituted chromatin to elucidate primary chromatin architecture in an archaeon without histones, the acido-thermophilic archaeon Thermoplasma acidophilum. We confirm and extend prior results showing that T. acidophilum harbours a HU family protein, HTa, that protects part of the genome from MNase digestion. Charting HTa-based chromatin architecture in vitro, in vivo and in an HTa-expressing E. coli strain, we present evidence that HTa is an archaeal histone analog. HTa-protected fragments are GC-rich, display histone-like mono- and dinucleotide patterns around a conspicuous dyad, exhibit relatively invariant positioning throughout the growth cycle, and show archaeal histone-like oligomerization behaviour. Our results suggest that HTa, a DNA-binding protein of bacterial origin, has converged onto an architectural role filled by histones in other archaea.
Project description:Methanococcus maripaludis is a methanogenic archaeon. Within its genome, there are two operons for membrane associated hydrogenases, eha and ehb. To investigate the regulation of ehb on the cell, an S40 mutant was constructed in such a way that a portion of the ehb operon was replaced by pac cassette in the wild type parental strain S2 (done by Whitman's group at the University of Georgia). The S40 and S2 strains were grown in 14N and 15N media with acetate separately. A biological replicate was made by switching the media. Mass spectrometry based quantitative proteomics were done on the mixtures to investigate the differences in expression patterns between S40 and S2. Keywords: isotope labeling mass spectrometry, quantitative proteomics
Project description:Chemical communication is crucial in ecosystems with complex microbial assemblages. However, due to archaeal cultivation challenges, our understanding of the structure diversity and function of secondary metabolites (SMs) within archaeal communities is limited compared to the extensively studied and well-documented bacterial counterparts. Our comprehensive investigation into the biosynthetic potential of archaea, combined with metabolic analyses and the first report of heterologous expression in archaea, has unveiled the previously unexplored biosynthetic capabilities and chemical diversity of archaeal ribosomally synthesized and post-translationally modified peptide (RiPP). We have identified twenty-four new lanthipeptides of RiPPs exhibiting unique chemical characteristics, including a novel subfamily featuring an unexplored type with diamino-dicarboxylic (DADC) termini, largely expanding the chemical landscape of archaeal SMs. This sheds light on the chemical novelty of archaeal metabolites and emphasizes their potential as an untapped resource for natural product discovery. Additionally, archaeal lanthipeptides demonstrate specific antagonistic activity against haloarchaea, mediating the unique biotic interaction in the halophilic niche. Furthermore, they showcased a unique ecological role in enhancing the host's motility by inducing the rod-shaped cell morphology and upregulating the archaellum gene flgA1, facilitating the archaeal interaction with abiotic environments. These discoveries broaden our understanding of archaeal chemical language and provide promising prospects for future exploration of SM-mediated interaction.