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ISSO Y2005 Annual Report | Contents The Effect of Modeled Microgravity on Microbial Gene Expression
• 23-26 Abstract--The effect of low-shear modeled microgravity (LSMMG) on microbial gene expression and physiology is being examined using functional genomics, survival assays, and molecular techniques in Escherichia coli. Reproducible changes in transcription were seen but no direct response to changes in the gravity vector was identified. Instead, absence of shear and a randomized gravity vector appeared to cause local extra-cellular environmental changes, which elicited reproducible cellular responses. In minimal media, the majority of the significantly up- or down-regulated genes of known function were associated with the cell envelope. Comparison with earlier studies of Salmonella enterica serovar Typhimurium conducted under similar growth conditions revealed essentially no similarity in genes, which were significantly up- or down-regulated. Given the substantial overlap in gene content between these closely related organisms, this result clearly demonstrates that different organisms may dramatically differ in their responses to medically significant low-shear and space environments. The project is part of a larger effort to characterize the types of organisms that may inhabit space craft environments and to understand how they might be affected by the space environment. |
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