A PATCH-CLAMP INVESTIGATION OF THE STREPTOCOCCUS-FAECALIS CELL-MEMBRANE

The patch-clamp technique was used to study the membrane of giant protoplasts from the gram-positive bacterium Streptococcus faecalis, demonstrating the presence of ion-conducting pores in the cytoplasmic membrane of procaryotes. The single channel recordings were characterized by a variety of conductances, ranging up to a few nanoSiemens, arising from stretch-activated, voltage-modulated, cooperative channels. Activation by stretch and voltage took place via both a decrease of the mean closed time and an increase of the mean open time of the channels, which are strictly controlled in intact cells. where they might constitute parts of a membrane apparatus or transport system.