Project description:Sulfur metabolism in the deep-sea cold seep has been mentioned to have an important contribution to the biogeochemical cycle of sulfur in previous studies. And sulfate reducing bacteria have also been considered to be a dominant microbial population in the deep-sea cold seep and play a crucial role in this process. However, most of sulfate reducing bacteria from cold seep still cannot be purely cultured under laboratory conditions, therefore the actual sulfur metabolism pathways in sulfate reducing bacteria from the deep-sea cold seep have remained unclear. Here, we isolate and pure culture a typical sulfate reducing bacterium Desulfovibrio marinus CS1 from the sediment sample of the deep-sea cold seep in the South China Sea, which provides a probability to understand the sulfur metabolism in the cold seep.
Project description:Recent studies have unveiled the deep sea as a rich biosphere, populated by species descended from shallow-water ancestors post-mass extinctions. Research on genomic evolution and microbial symbiosis has shed light on how these species thrive in extreme deep-sea conditions. However, early adaptation stages, particularly the roles of conserved genes and symbiotic microbes, remain inadequately understood. This study examined transcriptomic and microbiome changes in shallow-water mussels Mytilus galloprovincialis exposed to deep-sea conditions at the Site-F cold seep in the South China Sea. Results reveal complex gene expression adjustments in stress response, immune defense, homeostasis, and energy metabolism pathways during adaptation. After 10 days of deep-sea exposure, shallow-water mussels and their microbial communities closely resembled those of native deep-sea mussels, demonstrating host and microbiome convergence in response to adaptive shifts. Notably, methanotrophic bacteria, key symbionts in native deep-sea mussels, emerged as a dominant group in the exposed mussels. Host genes involved in immune recognition and endocytosis correlated significantly with the abundance of these bacteria. Overall, our analyses provide insights into adaptive transcriptional regulation and microbiome dynamics of mussels in deep-sea environments, highlighting the roles of conserved genes and microbial community shifts in adapting to extreme environments.
Project description:we applied metaproteomic approach to capture proteins from three size-fractionated microbial communities at the DCM in the basin of the South China Sea. The deep recovery of proteomes from a marine DCM plankton assemblage provides the highest resolution of metabolic activities as well as microbial niche differentiation, revealing a spectrum of biological processes carrying out by microbes at DCM of the SCS.
Project description:Marine viral concentrates (VCs) contains a substantial amount of non-cellular biological particles, e.g. viruses, gene transfer agents (GTAs) and membrane vesicles that are ecological significant. Metagenomic sequencing of VCs has been extensively applied to study the diversity and function potential of natural virions whereas information of nonn-viral components are often excluded for investigation. Here we apply a shotgun proteomic approach to characterize the origin and function of proteins in the VCs collected from the deep chlorophyll maximum (DCM) of the South China Sea. Using a custom database, we identified 636 non-redundant proteins represented by a total of 7220 spectra from the two VC samples. Cyanophages, pelagiphages, Phycodnaviridae and a group of uncultured viruses (previouly collected from DCM of Mediterranean Sea) contributed the most in the viral proteome. Seldom proteins related to RNA viruses and known GTAs were found despites of the presence of their sequences in the protein-searching database, suggested that these particles might be low abundant in the samples. Over 60% of identified spectra could not be assigned to viruses. The non-viral spectra were dominated by microbial groups of SAR324, SAR11, Actinobacteria and picoeukaryotic algae such as prasinophytes.Interestingly, we found that periplasmic proteins such as diverse ABC and TRAP transporters, and 56 kDa selenium-binding proteins, were enriched in this fraction.Together with other detected non-viral proteins,we could identify significant microbial functions, such as the utilization of glycine betaine, 3-dimethylsulphoniopropionate,and taurine by SAR11,and urea by prochlorococcus, nitrous oxide production by ammonia-oxidizing archaea and peroxide detoxification by unkonwn gammaproteobacteria. Our study of marine VCs demonstrates the potential application of metaproteomics to link the nano-size materials to the diversity of virions and interesting microbial functions in the ocean.