Project description:Competition among nitrate reducing bacteria (NRB) and sulfate reducing bacteria (SRB) for resources in anoxic environments is generally thought to be governed largely by thermodynamics. It is now recognized that intermediates of nitrogen and sulfur cycling (e.g., hydrogen sulfide, nitrite, etc.) can also directly impact NRB and SRB activities in freshwater, wastewater and sediment, and therefore may play important roles in competitive interactions. Here, using Intrasporangium calvum C5 as a model NRB, we performed comparative transcriptomic and metabolomic analyses to demonstrate that the reduced sulfur compounds cysteine and sulfide differentially inhibit respiratory growth on nitrate, and that inhibition by each can be selectively relieved by a specific carbon source. These findings provide mechanistic insights into the interplay and stratification of NRBs and SRBs in diverse environments.
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:Sulfate-reducing bacteria (SRB) play a pivotal role in the global carbon- and sulfur cycles, especially in the marine environment. Here, continental margins, coastal ranges, and shelf sediments stand out by their high input of organic matter, and more than 50% of their mineralization is achieved in the upper sediment layers, coupled to sulfate reduction. This turnover is mainly achieved by members of the family of Desulfobacteraceae of completely oxidizing SRB. Desulfonema magnum is a member of this family.
Project description:Sulfate-reducing bacteria (SRB) play a pivotal role in the global carbon- and sulfur cycles, especially in the marine environment. Here, continental margins, coastal ranges, and shelf sediments stand out by their high input of organic matter, and more than 50% of their mineralization is achieved in the upper sediment layers, coupled to sulfate reduction. This turnover is mainly achieved by members of the family of Desulfobacteraceae of completely oxidizing SRB. Desulfonema limicola is a member of this family.
