Effect of Dodine Acetate on the Electrophoretic Mobility of Neurospora crassa Conidia

Abstract

SUMMARY: The electrokinetic behaviour of intact conidia and cell walls of Neurospora crassa was studied using a micro-electrophoresis technique. By chemical and enzyme treatments it has been established that amino, carboxyl and phosphate groups are integral components of the spore surface; acid phosphate groups, however, were not found on the surface of washed cell walls. The fungicide dodine acetate reduced the negative charge on conidia to zero and, with increasing concentration, gave a positive charge to the spores: at lower fungicide concentrations the negative charge on the surface of cell walls and stabilized protoplasts was also neutralized. These results are consistent with an ionic reaction between the dodine cation and the carboxyl and phosphate groups of the cell. There was no evidence that the toxic reaction between dodine acetate and N. crassa conidia is located on the spore surface—the spores were completely killed before there was a perceptible reduction in electrophoretic mobility.