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STS-107 EXPERIMENT BACTER:  GROUND SIMULATION STUDY RESULTS. E. dL. Pulcini and B.H. Pyle.  Dept of Microbiology, Montana State University, Bozeman.

   A proteomic analysis of differential protein expression in Pseudomonas aeruginosa ATCC 29260 under conditions of simulated microgravity was performed.  Comparative control cultures of P. aeruginosa were grown under normal gravity (1 x G) conditions and maintained under identical conditions of temperature, oxygen, and nutrient availability. Simulated microgravity was accomplished using a clinostat system rotating at 80 rpm.  The bacteria were grown in a medium to stimulate exotoxin A virulence factor production during growth.  The analysis of variations in exotoxin A production was accomplished using ELISA, Western Blots and proteomic methodologies.  In order to better identify the physiologic changes that take place in simulated microgravity, a comparison of protein expression patterns using P. aeruginosa signaling mutants with mutations in the las, rhl, and las/rhl systems was made.  Results indicate variations in protein expression do occur in P. aeruginosa under conditions of simulated microgravity representing changes in metabolic and physiologic functions as well as changes in putative pathways for the production of virulence factors.  These results will allow for a better understanding of the factors involved in crew health and safety during space flight.

(Supported by NASA NAS2-14263 and Montana Space Grant Consortium NASA EPSCoR)

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