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:Zero-valent sulfur (ZVS) distributes widely in the deep-sea cold seep, which is important immediate in the active sulfur cycle of cold seep. In our preview work, a novel ZVS formation pathway discovered in the deep-sea cold weep bacterium Erythrobacter flavus 21-3 was described. However, whether this pathway worked and what function roles it played in the cold seep were unknown. In this study, E. flavus 21-3 was verified to produce zero-valent sulfur in the cold seep using genes soxB and tsdA as our preview report described. Based on proteomic data, stoichiometric methods and microscopic observation, this ZVS formation pathway benefited E. flavus 21-3 in the deep-sea cold seep. Notably, 30% metagenomes contained these two genes in the shallow sediments, which present the most abundant sulfur genes and active sulfur cycle in the cold seep sediments. It suggested that this sulfur formation pathway exist across many bacteria in the cold seep. This strongly indicates that this novel pathway might be frequently used by microbes and plays an important role in the biogeochemical sulfur cycle in cold seep.
2022-07-09 | PXD029383 | Pride
Project description:Transcriptomic analysis of the ZRK33 strain incubated in a deep-sea cold seep
Project description:The deep marine subsurface is one of the largest unexplored biospheres on Earth, where members of the phylum Chloroflexi are abundant and globally distributed. However, the deep-sea Chloroflexi have remained elusive to cultivation, hampering a more thorough understanding of their metabolisms. In this work, we have successfully isolated a representative of the phylum Chloroflexi, designated strain ZRK33, from deep-sea cold seep sediments. Phylogenetic analyses based on 16S rRNA genes, genomes, RpoB and EF-tu proteins indicated that strain ZRK33 represents a novel class within the phylum Chloroflexi, designated Sulfochloroflexia. We present a detailed description of the phenotypic traits, complete genome sequence and central metabolisms of the novel strain ZRK33. Notably, sulfate and thiosulfate could significantly promote the growth of the new isolate, possibly through accelerating the hydrolysis and uptake of saccharides. Thus, this result reveals that strain ZRK33 may play a crucial part in sulfur cycling in the deep-sea environments. Moreover, the putative genes associated with assimilatory and dissimilatory sulfate reduction are broadly distributed in the genomes of 27 metagenome-assembled genomes (MAGs) from deep-sea cold seep and hydrothermal vents sediments. Together, we propose that the deep marine subsurface Chloroflexi play key roles in sulfur cycling for the first time. This may concomitantly suggest an unsuspected availability of sulfur-containing compounds to allow for the high abundance of Chloroflexi in the deep sea.
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:Light was a ubiquitous environmental stimulus. Deep-sea microorganisms were exposed to a pervasive blue light optical environment. The utilization of blue light by deep-sea microorganisms, especially non-photosynthetic microorganisms, and the downstream pathway after light reception were obscure. Under the enrichment condition surrounded by blue light, a potential novel species named Spongiibacter nanhainus CSC3.9 from the deep-sea cold seep was isolated. Its growth and metabolism under blue light were significantly better than other wavelengths of light. Six blue light sensing proteins, including four BLUF (Blue Light Using Flavin) and two bacteriophytochrome, were annotated in the genome of strain CSC3.9. Then, with the assist of proteomic analysis, we demonstrated that 15960-BLUF was a crucial blue light receptor that interfered with motor behavior through chemotaxis pathway by means of in vivo and in vitro verification. In addition, 15960-BLUF mediated part of the blue light to promote the growth of strain CSC3.9. Further, we summarized the functional BLUF proteins from isolated marine microorganisms, and the high abundance distribution of BLUF similar to the downstream unresponsive domain type in strain CSC3.9 was demonstrated. The widespread distribution of BLUF protein in marine bacteria implied the extensiveness of this regulatory mechanism, and wavelength variation of light was a potential means to isolate uncultured microorganisms. This was the first reported in deep-sea microorganisms that BLUF-dependent physiological response to blue light. It provided a new clue for the blue light adaptation of microorganisms in disphotic zone.
2022-01-18 | PXD028001 | Pride
Project description:Amplicon analysis of deep-sea cold seep (V10 region)
Project description:Bacteria isolated from diverse environments were found to sense blue light to regulate their biological functions. However, this ability of deep-sea bacteria has been studied rarely. In this study, we found serendipitously that blue light stimulated excess zero-valent sulfur (ZVS) production of E. flavus 21-3, which was isolated from the deep-sea cold seep and possessed a novel thiosulfate oxidation pathway. Its ZVS production responding to the blue light was mediated by a light-oxygen-voltage histidine kinase (LOV-1477), a diguanylate cyclase (DGC-2902), a PilZ protein (mPilZ-1753) and the key thiosulfate dehydrogenase (TsdA) in its thiosulfate oxidation pathway. Subsequently, the thiosulfohydrolase (SoxB-277) was found working with another SoxB (SoxB-285) and being as substitute for each other to generate ZVS. This study provided an example of deep-sea bacteria sensing blue light to regulate thiosulfate oxidation. Deep-sea blue light potentially helped these blue-light-sensing bacteria adapt harsh conditions by diversifying their biological processes.
Project description:The existence of light in various deep-sea environments has been well established. Our previous research found blue light promotes zero-valent sulfur (ZVS) production in Erythrobacter flavus 21-3, a bacterium isolated from the deep-sea cold seep. E. flavus 21-3 can convert thiosulfate to ZVS through a novel thiosulfate oxidation pathway comprising a thiosulfate dehydrogenase (TsdA) and two thiosulfohydrolases (SoxB). Using proteomic analysis, bacterial two-hybrid system and heterologous expression assays, we found that infrared light also promotes zero-valent sulfur (ZVS) production in E. flavus 21-3. The bacteriophytochrome (bphp) Ef2bphp-15570 autophosphorylated and activated GGDEF domain-containing protein D0Y83_RS00450 to produce c-di-GMP. Subsequently, the PilZ protein mPilZ-1753 bound to c-di-GMP and activated downstream sulfur oxidation pathways. During this process, polyphosphate kinase 2 (PPK2) affects the content of c-di-GMP by competing for GTP, thereby together c-di-GMP regulating ZVS production, as well as other metabolic processes in E. flavus 21-3. This study provides a novel insight into a deep-sea non-photosynthetic bacterium which sensing infrared light to regulate sulfur metabolism through a bacteriophytochrome photoreceptor, thus offering new understandings perspectives on microbial utilization of light energy.