Isolation and characterization of a Listeria monocytogenes mutant strain hyperproducing virulence factors

Abstract

A mutant strain characterized by hyperproduction of a number of cell wall and supernatant proteins was isolated after N‐methyl‐N′‐nitro‐N‐nitrosoguanidine treatment of Listeria monocytogenes strain NCTC10527. Several of these proteins were identified as virulence factors. When a wild‐type strain was grown in the presence of activated charcoal it was shown to exhibit the same protein pattern as the isolated mutant.

New Listeria monocytogenes prfA* mutants, transcriptional properties of PrfA* proteins and structure–function of the virulence regulator PrfA

“…It is therefore tempting to speculate that the PrfA* mutant forms mimic the functional conformation assumed by PrfA during intracellular infection. Consistent with this, prfA * mutants are generally as virulent in vivo as wild‐type L. monocytogenes (Ripio et al ., 1996; Ermolaeva et al ., 1997; Shetron‐Rama et al ., 2003).…”

“…After each cultivation round, appropriate dilutions of the culture were plated onto BHI agar and incubated at the same temperature until colonies were visible. L. monocytogenes NCTC 10527 was subjected to nitrosoguanidine mutagenesis as described elsewhere (Ermolaeva et al ., 1997). Individual colonies were screened for PrfA* phenotype as indicated above (see ).…”