Cadaverine Inhibition of Porin Plays a Role in Cell Survival at Acidic pH

• DOI: 10.1128/jb.185.1.13-19.2003
• Publication Date: 2002-12-16T22:44:14Z
• Authors: Hrissi Samartzidou; Mahsa Mehrazin; Zhaohui Xu; Michael J. Benedik; Anne H. Delcour
• Keywords: Porin; Polyamine

When grown at acidic pH, Escherichia coli cells secrete cadaverine, a polyamine known to inhibit porin-mediated outer membrane permeability. In order understand the physiological significance of cadaverine excretion and inhibition porins, we isolated an OmpC mutant that showed resistance spermine during growth polyamine-resistant fluxes. Here, show addition exogenous allows wild-type survive 30-min exposure pH 3.6 better than expressing cadaverine-insensitive porin. Competition experiments between strains either or lack sensitivity porin confers survival disadvantage reduced pH. On basis these results, propose porins by excreted represents novel mechanism provides bacterial with ability acid stress.