Latrunculin A treatment reduces oxidant-induced [<i>PSI</i>⁺] formation.

<p><b>A.</b> Representative fluorescence micrographs are shown for a [<i>PIN</i>⁺][<i>psi</i>^-] strain treated with 10 μM LTA for 20 hours. Cells were fixed, and stained with rhodamine phalloidin to visualize the cortical actin cytoskeleton. <b>B.</b> Fluorescence micrographs are shown for a [<i>PIN</i>⁺][<i>psi</i>^-] strain treated with 100 μM hydrogen peroxide for 20 hours in the presence or absence of 10 μM LTA. The aggregate frequency is shown as the percentage of cells containing visible Sup35 foci from approximately 1000 cells counted. Error bars denote standard deviation; * marks statistical significance at p<0.01. <b>C.</b> [<i>PSI</i>⁺] prion formation was quantified in a [<i>PIN</i>⁺][<i>psi</i>^-] strain treated with 100μM hydrogen peroxide for 20 hours in the presence or absence of 10 μM LTA. Data shown are the means of three independent biological repeats expressed as the number of [<i>PSI</i>⁺] colonies per 10⁵ viable cells. Error bars denote standard deviation; * marks statistical significance at p<0.01. <b>(D)</b> [<i>PSI</i>⁺] prion formation was quantified in a [<i>PIN</i>⁺][<i>psi</i>^-] strain containing the <i>Sup35NM-GFP</i> plasmid following 1 and 24 h of copper induction in the presence or absence of 10 μM LTA. Data shown are the means of three independent biological repeats expressed as the number of [<i>PSI</i>⁺] colonies per 10⁴ viable cells. Error bars denote standard deviation; * marks statistical significance at p<0.01. <b>E.</b> Western blot analysis of cells grown under the same conditions as for panel D. Blots were probed with α-Sup35 and α-Pgk1 as a loading control.