Project description:Copper (Cu) is an essential micronutrient required as a co-factor in the catalytic center of many enzymes in bacteria. However, excess Cu is hazardous and can generate pleiotropic effects. Cu has been the metal of choice for piping used in household water distribution systems. Due to its leaching from pipelines, Cu is present at an elevated concentration in groundwater and in soil which is of public health concern. Sulfate-reducing bacteria (SRB) have been demonstrated to remove toxic levels of Cu. However, reports on the toxicity of Cu towards SRB have primarily focused on the degree of toxicity and subsequent elimination. In this study, we show in detail the Cu(II) stress-related effects on a model sulfate reducing bacteria, Desulfovibrio alaskensis G20. Cu(II) stress effects were assessed as alterations in the transcriptome through RNA-Seq at varying Cu(II) concentrations (5µM and 15µM). In the pairwise comparison of control vs 5µM, 61.43% of genes were downregulated and 38.57% genes were upregulated. In 15µM vs control, 49.51% genes were downregulated, and 50.5% genes were upregulated. The results indicated that the expression of inorganic ion transporters and translation machinery was massively modulated. Moreover, changes in important biological processes such as DNA transcription and signal transduction were observed at high Cu(II) concentration. In addition, metabolomics analysis indicated the effect of certain organic acids and amino acids in cellular metal buffering system and reducing oxidative damage to cells. These results will help us better understand the mechanism of Cu(II) stress response and provide avenues for future research.
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.
