FIGURE 8.
Schematic representations of the sigB, vir, and dlt operon associated mutations uncovered among the nisin sensitive L. monocytogenes field strains from our study. (A) In the sigB operon single base deletions causing RsbU truncations (RsbUΔ318AA and RsbUΔ226AA) and a 31367 bp deletion (causing loss of rsbR, rsbS, and rsbT genes and part of rsbV) were detected. (B) In the vir operon point mutations causing amino acid substitutions and single base deletion truncated proteins were detected in the virR and virB genes. (C) In the dlt operon a 1172 bp deletion (causing loss of lm00975, predicted hypothetical protein ORF and dltA N-terminus) as well as point mutations causing amino acid substitutions in dltB and dltD genes were detected.