LAUSR

Abstract The introduction of probiotic microbes into the spaceflight food system has the potential for use as a safe, non-invasive, daily countermeasure to crew microbiome and immune dysregulation. However, the microgravity effects on the stress tolerances and gene expression of probiotic bacteria must be investigated to confirm that benefits of selected strains will still be conveyed under microgravity conditions. The goal of this study was to evaluate the characteristics of the probiotic bacteria Lactobacillus acidophilus ATCC 4356 in a microgravity analog environment. L. acidophilus was cultured anaerobically under modeled microgravity conditions and assessed for differences in growth, survival through stress challenge, and gene expression compared to control cultures. No significant differences were observed between the modeled microgravity and control grown L. acidophilus, suggesting that this strain will behave similarly in spaceflight.