Influence of simulated microgravity on the transcriptome of the mutualistic bacterium Vibrio fischeri / Presenters: Mary Bishop, Alexandrea A. Duscher, Giorgio Casaburi, Jamie S. Foster

Faculty Mentor: Department of Microbiology and Cell Science, University of Florida, Space Life Sciences Lab, Merritt Island, FL

Microgravity is known to affect bacteria physiologically as well as induce changes in gene regulation. The effects of microgravity on pathogenic bacteria has been widely studied; however, little is known about beneficial bacteria in a simulated space environment. Vibrio fischeri are flagellated, bioluminescent bacteria that form a mutualistic relationship with the Hawaiian Bobtail squid, Euprymna scolopes. This squid-bacteria is a model because the same host-microbe communication is also utilized in the human body. This study focused on the impact of microgravity on gene expression in two strains of the symbiotic bacteria V. fischeri: wild-type and a mutant strain lacking the hfq gene. In previous studies, it has been found that hfq in V.fischeri is down-regulated when exposed to microgravity. Under space flight conditions, the absence of hfq impacts the symbiosis between squid and microbe negatively. Therefore, it is important to sequence the transcriptome of V.fischeri in order to discover other genes that are affected by space flight. Analyzing the transcriptome of V. fischeri will explain changes in functional gene expression that occurs in a reduced gravity environment. The microgravity environment was simulated using high-aspect ratio vessels (HARV). HARVs allow for the continued slow rotation and incubation of the cell culture, thereby simulating the constant state of falling astronauts experience in space. V. fischeri were exposed to microgravity conditions at two time points: 12 and 24 hours. RNA from the cultures were extracted, high quality RNA was converted to cDNA, and then sequenced. A complete bioinformatics analysis will target gene variances between gravity and microgravity conditions.