ISOLATION OF THERMOSENSITIVE MUTANTS OF YERSINIA-ENTEROCOLITICA BY TRANSPOSON INSERTION

During bacterial infection, pathogens are exposed to a variety of stim uli, e.g., sudden temperature increase on entering mammalian host or o xidative stress associated with exposure to phagocytes. Yersinia enter ocolitica, which is a facultative intracellular bacteria, responds to macrophage phagocytosis by the production of a set of stress proteins, which are also induced by heat shock (Yamamoto et al., 1994, Microbio l. Immunol. 38, 295-300). To examine the role of bacterial stress prot eins in the adaptation to environmental changes encountered during inf ectious processes, we have isolated stress-sensitive mutants from Y. e nterocolitica in which mini-Tn10 transposon insertions allow bacterial growth at 28 degrees C but prevent growth at an elevated temperature, 39 degrees C. Eight independent insertions were obtained and prelimin arily characterized by Southern blot hybridization and morphological a nalysis. (C) 1994 Academic Press, inc.