Simulated Microgravity Triggers a Membrane Adaptation to Stress in E. coli REL606

Investigating the evolution of Escherichia coli in microgravity offers valuable insights into microbial adaptation to extreme environments. Here the effects of simulated microgravity (SµG) on gene expression of E. coli REL606, a strain evolved terrestrially for 35 years is explored. We evaluated the transcriptomic changes for glucose-limited and glucose-replete conditions over 24 hours which illustrate that SµG increased the expression of stress response and cell membrane-related genes, particularly under glucose-limited conditions. A machine learning model predicted that glucose-limited SµG impacts the cellular membrane, while glucose-replete SµG also inhibits protein synthesis at stationary phase. These findings highlight the transcriptomic and physiological adaptations of E. coli to short term microgravity, offering a foundation for future research into the long-term effects of space conditions on bacterial evolution. To understand the effect of short-term exposure to microgravity in the REL606 strain of E. coli we grew samples for 24 hours in simulated microgravity conditions using vertical rotation. Control samples were grown in a horizontal rotating plane (rotating) and in a stationary fixture (static). Samples were further challenged by nutrient availability in glucose-limited and glucose-replete media. Samples were collected at initial, exponential, and stationary growth phase in biological quadruplicate and assays for transcriptomic changes via RNA-Seq.