Space flight increases Salmonella virulence in mammals, PNAS reports online this week. Salmonella typhimurium grown on a space shuttle mission showed altered gene expression and was more lethal to mice than control Salmonella grown on the ground. This work is "the first study to examine the effect of space flight on the virulence of a pathogen and the first to obtain the entire gene expression response of a bacterium to space flight," senior author Cheryl Nickerson of Arizona State University (ASU) in Tempe told The Scientist in an Email.In addition to its relevance for infectious disease risks in astronauts, the study also sheds light on bacterial behavior on Earth, especially its growth in biofilms and in the intestine, according to Max Mergeay of the Belgian Nuclear Research Center in Brussels, who was not involved in the work.Previous work on Salmonella grown in a space-flight simulator on Earth showed that...
Salmonella typhimuriumSalmonellastressSalmonellaSalmonellaSome researchLionello Bossiother workthoughtKerstin Höner zu BentrupSalmonellaLaura Frostless susceptibleThe ScientistHöner zu Bentrup said. "I think we were all very surprised to see how well they aligned, because the ground-based experiments can never really reflect what's going on in space," she told The Scientist. However, the simulator "cannot accurately model all aspects of space flight," Nickerson said. "There are important differences between the two environments that we always need to keep in mind."Melissa Lee Phillips mail@the-scientist.comLinks within this articleJ.W. Wilson, "Space flight alters bacterial gene expression and virulence and reveals a role for global regulator Hfq," PNAS, published online September 24, 2007. http://www.pnas.orgK.R. Chi, "NIH in space?" The Scientist, July 24, 2007. Halim, "The positive side of Salmonella," The Scientist, February 21, 2000. Nickerson Sonnenfeld, W.T. Shearer, "Immune function during space flight," Nutrition, October 2002. Johnston, "Debaffling biofilms," The Scientist, August 2, 2004. Mergeay Nickerson et al., "Microbial responses to microgravity and other low-shear environments," Microbiology and Molecular Biology Reviews, June 2004. Figueroa-Bossi et al., "Loss of Hfq activates the sigmaE-dependent envelope stress response in Salmonella enterica," Molecular Microbiology, November 2006. Sittka, "The RNA chaperone Hfq is essential for the virulence of Salmonella typhimurium," Molecular Microbiology, January 2007. Bossi Merrell et al., "Host-induced epidemic spread of the cholera bacterium," Nature, June 6, 2002. Guo et al., "A hydrodynamic mechanosensory hypothesis for brush border microvilli," American Journal of Physiology Renal Physiology, October 2000. Höner zu Bentrup http://www.biomedicalsciences.tulane.eduLaura Frost Fux et al., "Survival strategies of infectious biofilms," Trends in Microbiology, January 2005.

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