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.

Marine Microbiology Far From the Sea

“…Cells washed with 0.5 M NaCI lysed at low salt concentrations, but the quantitative requirements for different salts to prevent lysis varied considerably. On a molar basis, twice as much KCI as NaCl was needed and only one tenth to one hundredth as much of such divalent cation salts as MgCh or CaCh (27). These observations suggested to us that the salts were not preventing lysis due to osmotic effects but rather due to more specific interactions of the cations with the cell walls of the organisms.…”

Growth and lysis of the fish pathogen Moritella viscosa

“…Early studies of psychrophilic marine bacteria were directed towards their sensitivity to lysis, as halophilic bacteria tend to lyse when suspended in a hypotonic medium. At this time it was determined that the susceptibility of marine bacteria to lysis differs considerably between species (MacLeod and Matula 1962; D’Aoust and Kushner 1971; Laddaga and MacLeod 1982). The findings reported here are consistent with the earlier observations on the effect of cations to prevent lysis because of the specific interactions with components of the cell envelope and the capacity to balance the osmotic pressure of the cells.…”

Significance of Na+in the fish pathogen,Vibrio anguillarum, under energy depleted condition

“…A further function of intracellular Na + is in membrane stabilization [22–24]. When bacteria are starved, they utilize membrane phospholipids [25], a process that could result in loss of cell integrity [26].…”

“…Thus, compared with the growth phase, membrane stabilization becomes more important for starved bacteria. As marine bacteria utilize Na + to stabilize their membranes [22–24], this function of Na + is probably one reason why V. anguillarum M93 and V. angustum S14 can survive well in the presence of Na + (Fig. 2).…”