Inhibition of predation by Bdellovibrio bacteriovorus and Micavibrio aeruginosavorus via host cell metabolic activity in the presence of carbohydrates.

Bdellovibrio bacteriovorus and Micavibrio aeruginosavorus are highly motile Gram-negative predatory bacteria with the potential of being used as biocontrol agents or living antibiotics. It was suggested previously that sugar-binding proteins play a role in M. aeruginosavorus and B. bacteriovorus host specificity and predator-prey interactions. The effect of carbohydrates on predation was reexamined in this study. It was demonstrated that the presence of carbohydrates could indeed block predation. However, further investigation demonstrated that inhibition of predation was due to medium acidification by the metabolic activity of the host and not to a blocking of a putative sugar-binding protein. The data presented here might be of value when storing, growing, and cultivating predatory bacteria, as well as when considering environmental conditions that might influence predation in the field.