Alteration of virulence phenotype of the <i>psm-mec</i>-transformed <i>S. haemolyticus</i>.

Abstract

<p>(A) AgrA expression in <i>S. haemolyticus</i> strain transformed with pND50 as an empty vector, pF carrying intact <i>psm-mec</i>, pC1 carrying a stop codon-mutated <i>psm-mec</i>, or pM1 carrying a promoter-deficient <i>psm-mec</i> was examined. Protein (2.8 µg) was electrophoresed in each lane and subjected to Western blotting using anti-AgrA IgG. A representative result from two independent experiments is shown. (B) Hemolysin production of <i>S. haemolyticus</i> strain transformed with pND50, pF, pC1, pr pM1 was measured on tryptic soy agar plates containing 5% sheep erythrocytes. A color-changed region around the colonies reflects the lysis of erythrocytes. (C) PSMs in <i>S. haemolyticus</i> strains transformed with pND50 or pF were detected by reversed-phase HPLC. Respective PSM species were identified by LC/ESI-MS. (D, E, F) The amounts of PSMβ3, PSMβ2, and PSMβ1 in the <i>S. epidermidis</i> strain transformed with pND50, pF, pC1, or pM1 were measured by reversed-phase HPLC. The vertical axis represents the relative value to the amount of PSMs in the pND50-transformed strain. Data shown are means ± standard deviations from three independent experiments. Asterisks indicate a Student’s t-test p value less than 0.05 between the pND50-transformed stain and the others. (G) Biofilm formation of the <i>S. haemolyticus</i> strain that was transformed with pND50, pF, pC1, or pM1 was examined. Data shown are means ± standard deviations from three independent experiments.</p