Analysis of bacterivorous protozoa in the natural environment

Abstract

 Bacterivorous protozoa in the Hirose River were enriched with prey bacteria and analyzed. Additional analyses were also carried out by using spring water, groundwater, and soil extract as other sources of protozoa. Although Cupriavidus bacterium was mainly used as prey, other three bacteria that belong to genus Pseudomonas, Bacillus, and Rhodcoccus were also used. Protozoa that ingested bacteria were observed at all sampling stations along the river. In most cases, protozoa that clasified to Chrysophyceae were observed despite of prey bacterial strains. The same type of protozoa were appeared when the other environmental samples was used. These results suggest that Chrysophyceae may play an important role as predator of bacteria introduced in the natural environment.