FIG. 7.

Inhibition of motility and lysis of A. cochlioides zoospores treated with various doses of xanthobaccin A. Xanthobaccin A was first dissolved in a small quantity of DMSO and then serially diluted with distilled water. Appropriate amounts of a sample suspension were added to the aqueous zoospore suspension. The final DMSO concentration was always less than 1% in the zoospore suspension. The inhibition of motility and lysis of zoospores were observed microscopically (magnification, ×20) (for details see Table 1) 3 h after the treatment with xanthobaccin A, and the percentages of activity were calculated as described previously (16). DMSO alone (final concentration in the zoospore suspension, 1%) was used as the control and did not have any effect on the motility and lysis of the zoospores. The data are the averages ± standard errors of at least three replications for each dose of xanthobaccin A.