Effects of kepone on gram-negative bacteria: alterations in composition of envelope proteins

Kepone was found to penetrate readily into several Gram-negative bacteria, accumulating in the inner membrane. About 62% of the Kepone was found to be associated with the cytoplasmic membrane and 38% with the outer membrane of mid-exponential phase cultures of Escherichia coli K-12 growth in medium containing Kepone. Alterations in cell envelope protein composition were observed in Gram-negative bacteria grown in the presence of high concentrations of Kepone. The alteration in cell envelope protein profile was reversible. The concentration of an inner membrane protein of molecular weight 34 000 decreased four-fold in cells of Pseudomonas aeruginosa K03 grown in the presence of >10 μg Kepone ml⁻¹. Ten envelope proteins of E. coli, including pore-forming OmpF and OmpC proteins, either increased or decreased in concentration when cells were grown in broth containing Kepone at 500 μg ml⁻¹. The overall protein, lipoprotein and lipopolysaccharide composition of the Gram-negative bacterial cell envelope did not appear to affect susceptibility to Kepone. This study was undertaken in view of the serious nature of Kepone pollution of the James River in Virginia, USA.