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.
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:Chromosome segregation is a vital process for all organisms. The mechanisms underpinning chromosomal partitioning in the archaeal domain remain elusive. Our group has identified the first chromosome segregation system in thermophilic archaea. Sulfolobus solfataricus partition system consists of SegA, an orthologue of bacterial Walker-type ParA proteins; SegB, an archaea-specific DNA binding protein and a cis-acting DNA region. ChIP-seq experiments disclosed multiple SegB binding sites scattered over the chromosome and revealed a novel DNA binding motif.