Molecular Mechanism for Nutritional Stress Tolerance in Oleidesulfovibrio alaskensis G20 — 50p — Dheeraj  Raya_¹, Angel Lu², Saurabh Sudha Dhiman³

¹Civil and Environmental Engineering, ²Chemistry, Biology and Health sciences, ³Civil and Environmental Engineering, Chemistry, Biology and Health sciences

The bacterial response mechanism to nutritional stress involves molecular pathways that enable bacteria to adapt and thrive in a nutrient-limited environment. To decipher the underlying molecular mechanisms governing the transition from exponential phase to stationary phase under diminishing nutrient conditions in sulfate-reducing bacteria (SRB), a combinatorial approach of temporal transcriptomics analysis and ab-initio simulation, has been deployed in model strain, e.g., Oleidesulfovibrio alaskensis G20 (OA-G20), widely documented for microbially induced corrosion. Approximately, 23.7 % of genes were consistently upregulated during both the exponential (3^rd day) and stationary (9^th day) phase, including genes associated with type IV pili, such as flp and tadE, exhibiting high upregulation in both conditions. Transcriptomics analysis revealed the downregulation of genes linked with stress response, transcription and translation. These results underscore the pivotal role of pili in facilitating the adaption and stress tolerance under nutrient-deficient conditions across growth phases. Through the density functional theory (DFT) analysis, the electronic structure of Flp pili revealed the electrostatic charge distribution along the pili and low electronic HOMO-LUMO gap, indicating its potential involvement in extracellular electron transfer. The electronic structure further substantiates the significance of the C-terminal region of pili in catalyzing the last step of electron transfer. An in-depth analysis of Flp pili biogenesis and electronic properties will aid in engineering future synthetic microbiomes for biomanufacturing applications and have larger insights into biocorrosion research.

South Dakota Mines
Dr. Saurabh Sudha Dhiman