[Isolation and study of a new marine bacterium growing on hydrocarbons. II. Mechanism of lysis and viability (author's transl)].

The growth of the marine bacterium (L.16.1) is strictly dependent on the presence of well-defined NaCl concentrations (100 mM on alkanes and 75 mM on acetate, pyruvate or propionate) in the medium. L.16.1 cells undergo lysis on transfer from high to low ionic environment. This lytic phenomenon, which can be prevented by the presence of Na+ or divalent cations, appears to be due to the loss of Mg++ and Ca++ by the cells. Evidence for this hypothesis is provided by the assays of intracellular and extracellular Na+, K+, Mg++ and Ca++ concentrations. The maintenance of the cell integrity of the organism does not depend on the medium osmolarity, since osmotic compounds such as sucrose, glycerol or mannitol cannot prevent lysis. All of the ions which can maintain the cell integrity are not likewise able to keep viability; this has been found to be a function of Na+ concentration (70% survival after 24 hours in 400 mM NaCl, only 10% in 50 mM MgSO4).