Permeability of Phenyl-Hg+-resistant and Phenyl-Hg+-susceptible Isolates of Pyrenophora avenae to the Phenyl-Hg+ Ion

Abstract

SUMMARY The permeability of two phenyl-Hg t-resistant and two phenyl-Hg+-susceptible isolates of Pyrenophora avenae Ito & Kuribay. to the phenyl-Hg+ ion was investi- gated. Similar amounts of phenyl-Hg+ entered the living mycelium of both resistant and susceptible isolates. No difference was detected in the numbers of thiol groups present on the wall, although the apparent free space of susceptible isolates toward the phenyl-Hg+ ion was greater than that of resistant isolates. The mechanism of resistance to the phenyl-Hg+ ion is probably based on a detoxification mechanism involving the binding of the toxic ion to metabolically inessential molecules within the mycelium.