Deciphering osmotic stress responses: a comparative analysis of mechanisms in Gram-positive and Gram-negative...

Bacteria are constantly challenged by osmotic pressures in their natural environments, necessitating sophisticated detection, signal transduction, and response systems for survival. These osmotic stress responses are intricate and involve multi-level control processes that are crucial for bacterial homeostasis. A significant factor influencing osmotic regulation is the morphological structure of bacteria, notably the distinct cell wall compositions of Gram-positive and Gram-negative types, which directly impact their regulatory mechanisms. This review focuses on contrasting the osmotic regulation systems between Gram-positive and Gram-negative bacteria, exploring their preferences for compatible solutes, the essential role of c-di-AMP in Gram-positive bacteria, and unique gene domains in two-component systems (TCS). By highlighting these distinctions, the review aims to deepen the understanding of how these systems function and their implications for bacterial virulence, pathogenicity, survival, and reproduction. Exploiting structural vulnerabilities in pathogen-specific TCS offers routes to narrow-spectrum antimicrobials that spare commensal microbiota. Such insights are pivotal for understanding bacterial adaptation within diverse hosts and environments.