Effect of δ-toxin knockout on the colony-spreading activity in SA564 and FRP3757 strains.

<p>A. The colony-spreading activities of the <i>hld</i>-wild-type strain (WT) or the δ-toxin knockout strains (Δ<i>hld1</i>, Δ<i>hld2</i>) of SA564 or FRP3757 strains were examined. <i>S</i>. <i>aureus</i> overnight cultures were spotted on 0.24% soft agar plates and incubated at 37°C (SA564 and FRP3757) or 30°C (FRP3757). The photographs were obtained at 6 h incubation (SA564), 7 h incubation (FRP3757, 37°C), and 28 h incubation (FRP3757, 30°C). B. The diameters of the giant colony in <i>A</i> were measured. Data are the means±standard errors of two independent experiments performed in triplicate. Asterisks indicate Student’s t-test p-value between WT and Δ<i>hld1</i> or between WT and Δ<i>hld2</i> less than 0.05.