Abstract
We presumed the water quality from aquatic insects and investigated bacterial generic composition of two distinct stations at the Ina River and the Minoh River, northern part of Osaka, to grasp the relationship between aquatic environment and bacterial generic composition. The ratio of colony forming unit to total bacterial number (CFU/TDC value) was increased as water pollution was intensified. Pseudomonas group bacteria constitute the dominant population regardless of pollution levels. At the polluted station, Kuwazu, Alcaligenes group bacteria were the dominant. At the unpolluted one, Takiue, Aeromonas group bacteria were observed but Vibrio group was not. And an interestingly reverse result was obtained at the polluted station. The distribution of GC content measured on about each 50 strains isolated from two stations was quite different and suggested that its distribution pattern would be a useful indicator in evaluating the pollution levels in aquatic environments.
