TBI Virtual Seminar: Dr. Rajesh Sani
- Monday, November 8, 2021 from 3:10pm to 4:00pm
- Plant Biosciences Building - view map
Presentation: “Epigenome and transcriptome of Desulfovibrio alaskensis G20 under copper stress”
Rajesh Sani is a Chemical and Biological Engineering Professor at South Dakota School of Mines. He has been the PI, co-PI, or Senior Personnel on $44.5 million (current $34.86 million) in funded research for 41 research projects. His research is focused on both basic and applied research in Extremophilic Bioprocessing, Rules of Life in Biofilms grown on 2D materials, Space biology, Biocatalysis, Biopolymers, Gas to liquid fuels, and Genome editing of bacteria. Dr. Sani’s group has been working on extremophiles isolated from the deepest mine in North America, Homestake Gold Mine (7,800 ft.) for solid waste conversion under thermophilic conditions (≥60ºC). Homestake Gold Mine, known as Sanford Underground Research Facility (SURF), is in the Black Hills, South Dakota, USA. Using soil/biofilm samples from the SURF, the Sani group have isolated 560 unique thermophilic cellulose- and xylan-degrading and -fermenting pure cultures. These unique thermophiles are currently being used to produce biofuels and value-added products in single step bioprocessing of various inexpensive regional untreated biomass.
About his talk:
The molecular response mechanisms of sulfate-reducing bacteria (SRB), which corrodes various metal surfaces, are not well understood. Here, we combine physiological, spectroscopic, microscopy, and omics (transcriptomics and epigenomics) analyses to provide a comprehensive view on the pathways activated in a model SRB, Desulfovibrio alaskensis G20 (DA G20), in response to Cu. Detailed analysis of the differently expressed genes (transcriptomics) suggests involvement of putative molecular mechanisms (e.g., metal-ion binding, transporter activity, ATP binding, and hydrolase activity) and biological processes (e.g., transcription, translation, and phosphorelay signal transduction) in DA G20 response to Cu. In-terms of cellular component, integral components of membrane were highly differentially expressed in response to Cu. Radical S-adenosyl-L-methionine (SAM)-domain containing protein, which is responsible for metal ion binding, was upregulated, while the flagellar basal body protein, which helps in motility, was downregulated in the presence of Cu. Results also indicated that transcription factor families associated with stress responses were differentially expressed with Cu. Epigenetics analysis of DA G20 under Cu stress mapped the differentially methylated (m5C methylation) genes distributed across CHH, CHG and CPG genomic islands. The result revealed 37 genes with de-novo methylation that includes methyltransferase genes involved in the transfer of methyl group from SAM to other carbon atoms of differentially methylated genes and the genes involved in sensing extracellular change in environment. Increase in the methylation of chemotaxis and flagellar proteins, transcription regulation, metal ion binding, lipid metabolism, and energy metabolism could suggest their roles to overcome Cu stress. Our omics data has allowed us to identify several possible molecular mechanisms adopted by DA G20 to cope with Cu toxicity. These results are currently being used as a baseline for gene expression profiles of DA G20 biofilms grown on bare copper and copper coated with 2D materials’ surfaces.
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