[The surface membrane charge of bacteria and its role in serine proteinase secretion by Bacillus subtilis cells]

Univalent, bivalent and trivalent metal cations increase the fluorescence yield of 9-aminoacridine in the suspensions of chromatophores of the purple nonsulfur bacterium Rhodospirillum rubrum isolated thylakoid membranes and cells of cyanobacterium Anabaena variabilis, cells Bacillus subtilis. The active cation concentrations increase about in 10 times with the decrease of their valency by one. It points to the fact that the changes in 9-aminoacridine fluorescence serve for the monitoring of the surface charge of bacterial membranes. The negative surface charge of B. subtilis cells increases before the onset of the serine protease secretion. The metal cations stimulate the serine protease secretion by B. subtilis cells, the stimulating effect correlates with the action of cations on the 9-aminoacridine fluorescence yield. It is suggested that the surface charge of cytoplasmic membrane regulates the formation and release of serine protease by the cells of B. subtilis.