[Isolation and study of a new marine bacterium growing on hydrocarbons. III. Oxidation of substrates and effects of detergents on the cells (author's transl)].

The oxidation of exogenous hexadecane by cells of strain L.16.1 is a function of intracellular and extracellular Na+ and K+ concentrations. The cells which lost their Na+ as a result of washing in the absence of sodium chloride oxidize hexadecane at a very low rate. Washings in the absence of Mg++ and Ca++ do not result in a similar decrease of the respiratory activity. The latter cannot be maintained--or restored after decrease--by the divalent cations which are active in preventing cytolysis (see the preceding paper). A possible explanation for this Na+ dependence could lie in a particular role played by Na+ inthe cytoplasmic membrane and in some function related to the oxidative activities of the cell membrane. From other studies carried out with ionic detergents it was observed that growth and respiratory activity are inhibited by very low concentrations of these compounds contrary to non ionic detergents which can serve as growth substrates and are oxidized like hexadecane or acetate. It is concluded that the bulk of our results could best be accounted by assuming that the membranes of halophilic bacteria are organized according to a specific organization scheme.