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: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 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.