Biophysical Society Thematic Meeting | Stockholm 2022

Physical and Quantitative Approaches to Overcome Antibiotic Resistance

Poster Abstracts

3-POS Board 3 POST-EVOLUTIONARY 'RESCUER' GENES Dilan Can 1,2 ; Enes Seyfullah Kotil 2 ; 1 Yildiz Technical University, Graduate School of Science and Engineering, Molecular Biology and Genetics, Istanbul, Turkey 2 Bahcesehir University, Medical School, Department of Biophysics, Istanbul, Turkey When bacteria are forced to grow under stressors or changed environmental conditions, those with the most suitable genotype for these conditions quickly replicate, forming most of the current population. Thus, bacterial evolution takes place. Therefore, there are many theoretically suitable solutions for many challenging conditions. The biggest problem among these solutions is the resistance developed by bacteria against antibiotics, and it is a worrying global problem. Knowing the evolutionary trajectories that mediate resistance will be critical to winning this battle. In a situation that is not emphasized enough, which genes are more critical in evolved bacteria for their current 'new' situation? Bacteria that have become resistant to a drug depend on the presence of specific genes to normalize their growth rate to stabilize their adaptation. Thus, the importance of that gene in the evolved bacteria changes.To test this hypothesis, We identified ten genes that affect fitness cost involved in cellular stress response, central carbon, amino acid, and lipid metabolism. The genes were selected based on flux balance analysis and other quantitative methods. We inhibited these ten genes with CRISPR interference (CRISPRi) in E.coli strains, and we applied adaptive laboratory experiments (ALE) against four antibiotics with different mechanisms of action. We then examined the effect of these genes on the growth rate after evolution. Decreased expression of targeted genes and decreased growth rates exhibited coordination. The results obtained reflected these targeted genes 'rescuer' role in the evolution. When bacteria evolve against an antibiotic, these genes become essential for the bacteria's new self. Highlighting these genes is promising in finding practical solutions against antibiotic resistance. In addition, these 'post-evo genes' will be essential in accelerating identifying candidate genes for new antibiotic discovery or cellular pathways to target.

55