Free- swimming bacteria transcriptionally respond to shear flow

• 成果类型: Article
• 署名作者: Ramachandran, Ashwin; Stone, Howard A.; Gitai, Zemer
• 署名单位: Princeton University; Princeton University
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-14871
• DOI: 10.1073/pnas.2406688121
• 发表日期: 2024-10-15
• 关键词: pseudomonas-aeruginosa; gene-expression; iv pili; network; genome; GROWTH; anr

摘要

Surface- attached cells can sense and respond to shear flow, but planktonic (free- swimming) planktonic bacteria can transcriptionally respond to flow, inducing expression changes that are beneficial in flow. Specifically, we use microfluidic experiments and quantitative modeling to show that in the presence of flow, planktonic Pseudomonas aeruginosa induce shear rate-dependent genes that promote growth in low- oxygen environments. Untangling this mechanism revealed that in flow, motile P. aeruginosa spatially redistribute, leading to cell density changes that activate quorum sensing, which in turn enhances the oxygen uptake rate. In diffusion- limited environments, including those commonly encountered by bacteria, flow- induced cell density gradients also independently generate oxygen gradients that alter gene expression. Mutants deficient in this flow- responsive mechanism exhibit decreased fitness in flow, suggesting that this dynamic coupling of biological and mechanical processes can be physiologically significant.