LASER-ABLATION OF THE CELL-WALL AND LOCALIZED PATCH CLAMPING OF THE PLASMA-MEMBRANE IN THE FILAMENTOUS FUNGUS ASPERGILLUS - CHARACTERIZATION OF AN ANION-SELECTIVE EFFLUX CHANNEL

We have used a pulsed u.v. laser to ablate the cell wall of the filame ntous fungus Aspergillus niger van Tiegh., and expose the plasma membr ane at defined points along the hypha. Using the patch clamp technique , giga ohm seals (up to 20 G Omega) and recordings of plasma membrane ion channels were obtained. We describe, for the first time in fungi, a 43 pS plasma membrane anion efflux channel. Its potential role in ce ll signalling and pH homeostasis is discussed.