Cell envelope components of Yersinia pestis grown in intraperitoneal diffusion chambers

The electrophoretic profiles of penicillin binding proteins (PBPs) and oute r membrane proteins (OMPs) of Yersinia pestis EV 76 were determined followi ng in vivo growth in diffusion chambers implanted in the peritoneal cavity of mice. In contrast to Y. pestis grown under in vitro conditions which act ivate the low calcium response (LCR) regulon there was no significant quali tative or quantitative change of the PBP profile of Y. pestis cells during growth in diffusion chambers for up to 72 h following implantation in mice. Three OMPs, with molecular weight of 100, 60 and 58 kDa, were expressed in Y. pestis cells grown for 24 h, but not at 48 h or at 72 h, in diffusion c hambers. These results indicate that growth of Y. pestis in intraperitoneal diffusion chambers activates genes which might be relevant to the growth i n the mammal host.