An agarose slide method to follow the fate of bacteria within digestive vacuoles of protozoa.

A method to follow the fate of ingested bacteria within digestive vacuoles of protozoa is presented. Tetrahymena pyriformis, previously fed with bacteria, is deposited onto glass microscope slides covered with a film of nutritive agarose. The protozoa lyse and the digestive vacuoles containing the bacteria stay undamaged and can be observed microscopically. After incubation, microcolonies reveal those vacuoles which contained living bacteria. The method can be used to study the survival ability of the ingested bacteria. It is a potentially valuable technique for studies on digestion efficacy, virulence ability, or escape mechanisms of bacteria from digestion.