Effect of 2,4,5-trichlorophenol on hyphal membrane potentials in rhythmic mutants of Neurospora crassa.

The uncoupler 2,4,5-trichlorophenol (TCP) was used to test for differences in maintaining the hyphal membrane potentials in the wild type and rhythmic mutants of Neurospora crassa. Trichlorophenol (0.1 mmol·1(-1)) resulted in a depolarization of 93 mV (wild type) and 144 mV in the mutant clock. A total recovery was achieved in both strains after washing out the uncoupler. The circadian conidiation mutant band was more sensitive than the two other strains and showed two different reaction patterns: one with delayed reaction, total breakdown and without recovery; the other one with nearly immediate reaction, slow but not entirely total decline and partial recovery. These differences are discussed in their relation to the circadian rhythm of conidiation.