Transcriptional profiling of probiotic Escherichia coli Nissle 1917 under multiple environmental stresses: Simulated microgravity, microaerobic, and co-culture conditions

Environmental factors can substantially alter the physiology of probiotics, yet their transcriptomic responses under multiple simultaneous stresses remain poorly understood. Among these factors, a previous study has shown that the low-shear environment induced by simulated microgravity elicits mild stress in the well-known probiotic Escherichia coli Nissle 1917 (EcN). In this study, we investigated the impact of additional environmental stressors on the transcriptomic profile of EcN by introducing microaerobic conditions and co-culture with a pathogenic Pseudomonas aeruginosa PAO1 (PAO1), in combination with simulated microgravity. Under the combined condition of simulated microgravity and microaerobic stress, EcN maintained stable growth while upregulating genes involved in anaerobic respiration and biofilm formation, indicating effective adaptation to oxygen-limited environments. Howev…