NUTRITION AND METABOLISM OF MARINE BACTERIA: XI. SOME CHARACTERISTICS OF THE LYTIC PHENOMENON

Abstract

Five marine bacteria examined were found to differ considerably in lytic susceptibility. Some lysed completely below 0.15 M NaCl while suspensions of others contained some whole cells at 0.025 M NaCl. In general NaCl and LiCl were more effective than KCl or NH₄Cl in protecting against lysis and the loss of ultraviolet-absorbing materials from the cells. KCl could spare the requirement for NaCl to prevent lysis. Mg⁺⁺and other divalent cations at 0.05 M or less completely prevented lysis of all but one of the organisms. Sulphate salts stabilized the cell suspensions better on incubation than did chlorides for four of the organisms. For the fifth the reverse was true. The lytic action of ethanol and glycerol could be prevented by NaCl or sucrose. The concentrations of the latter required to prevent lysis remained unchanged when ethanol or glycerol was included in the suspending medium. Cells washed essentially free of electrolytes with 0.5 M sucrose retained their morphological characteristics. The observations are considered in relation to the distinction between marine bacteria, halophiles, and terrestrial bacteria and to current theories of the mechanism of lysis of bacterial cells. The results are not consistent with the hypotheses either that primarily osmotic effects are involved or that electrolytes are required to maintain the cell wall.