MEMBRANE ELECTROGENESIS AND THE PROBLEMS OF CELL-DIFFERENTIATION IN MYCELIAL FUNGI

Electrophysiological studies of fungal mycelium revealed that hyphae c ontain 600- to 800-mu m-long electrically interconnected ensembles com prising cells with different physiological functions. The operation of the system of electrically interconnected ensembles in a hypha is sub ject to genetic control. A general photoregulatory mechanism controls the light-induced changes in the electrophysiological properties of th e hypha and also gene induction. Hyperpolarization of the plasmalemma of the illuminated cells of the hypha is energy-dependent and involves H+-ATPase. Similar to light-induced gene expression, it presumably im plicates the cAMP system. However, the electrogenic system of plasma m embrane is unlikely to be mandatory for the message from the photorece ptor to reach the genome. The functional role of the electric response s of the membrane to illumination consists in synchronizing the operat ion of individual cells, characterized by considerable electrophysiolo gical heterogeneity.