The Effect of Simulated Microgravity on Microbial Gene Expression

of living in and adapting to a far larger range of environmental conditions than are normally encountered in the usual laboratory environments. Even with full knowledge of an organism’s gene content, it is currently impossible to predict how expression patterns will change in different situations. Thus, usual laboratory growth conditions may not invoke key aspects of an organism’s potential response. Such studies thereby may conceal behaviors that in a different environment may contribute to undesirable phenomena such as pathogenesis. One such case is the low-shear, lowturbulence environments present in utero, at the brush border microvilli of epithelial cells, and other medically important host environments. 1 Another example is the space environment characterized by microgravity and high background radiation. In this case, the absence of gravity also produces a low shear environment, which likely results in microorganisms having difficulty in removing themselves from immediate surroundings that have been nutrient depleted and have received waste products. 2