A COMPARISON OF THE SURVIVAL OF INTRAPERIPLASMIC AND ATTACK PHASE BDELLOVIBRIOS WITH REDUCED OXYGEN

The ability of intraperiplasmic and attack phase bdellovibrios to surv ive and/or grow under anoxic and microaerobic conditions was examined. Both halotolerant and nonhalotolerant bdellovibrio strains were exami ned. In all instances, the bdellovibrio strains were unable to grow un der anoxic conditions, but were able to survive for periods of time in both the extracellular and intraperiplasmic forms. However, the intra periplasmic organisms were observed to survive longer. Increased tempe rature hastened the loss of viability of both forms of the predatory b acteria in oxic and anoxic environments. Under microaerobic conditions , halotolerant bdellovibrios were observed to grow, although at a slig htly reduced rate than in atmospheric oxygen, while two nonhalotoleran t isolates survived but did not grow. The ability of attack phase bdel lovibrios to survive in an anoxic environment for up to nine days and their growth or survival under microaerobic conditions greatly expands the possible ecological niches in which the predators may be active m embers of the microbial community.