Mutation frequency in the <i>csrS/csrR</i> and <i>rgg</i> genes.

acsrS mutation affects significantly the expression of slo gene [18], and the mutant shows mucoid colony because the expression of the capsule synthesis operon is increased [4],[39]. The function of CsrS was determined by colony morphology and by increase of SLO production. bcsrR mutation does not affect significantly the expression of slo gene [18]. The cause of SLO increase in the 9 csrR mutants was described in the section of Discussion. The csrR mutant shows mucoid colony because the expression of the capsule synthesis operon is increased [4],[39]. The function of csrR was determined by colony morphology. crgg mutation affects significantly the production of slo gene [Figure 1, [16]] and SpeB [14], [16]–[17]. The function of Rgg was determined by the increase of SLO production and the decrease of SpeB production.