SOME FEATURES OF SALINE-SENSITIVE PHENOMENON IN ESCHERICHIA COLI-PROTECTION AND RECOVERY BY MAGNESIUM ION

Abstract

The cells of Escherichia coli at the logarithmic phase of growth lost their colony-forming ability when the cells were suspended in 0.15M sodium chloride in Tris buffer. The presence of magnesium ion in Tris buffer containing 0.15M sodium chloride, in which the cells were suspended, protected the cells from the injurious effect of sodium chloride. A similar protection by calcium or manganese ion was also observed. When sodium chloride-treated cells were incubated immediately in Tris buffer containing magnesium, the colony-forming ability was recovered rapidly. An almost complete recovery by magnesium was observed. No such remarkable recovery was noted by incubation with calcium or manganese. A significant release of magnesium from the cells was observed during the incubation in sodium chloride. Therefore, the loss of viability is due, at least in part, to the release of magnesium ion from the cells.