グラム染色法による底泥の細菌数の測定

抄録

Sediments collected in the Edo river mouth, a polluted area, were quantitatively diluted by seawater diluent, smeated on glass slides, and Gram stained. Under a light microscope at 1500 magnigficaion, bacterial cells with a definite boundary were counted and divided into 4 groups on the basis of cell morphology and Gram reaction. Also, diluted sediments were inoculated onto PYBG and 1/20 PYBG agar plates, and incubated at 20°C for 5 days under aerobic and anaeribic conditions.
Total direct counts ranged from 10⁸ to 10⁹g^-1 in the sediments; Gram-negative rods were dominant. 60-70% of the bacteria observed were attached to organic matter. Total viable counts were 10⁵ to 10⁷g^-1, which were 0.03 to 2.1% of the total direct counts. Major components were aerobic and facultatively anaerobic Gram-negative rods and bacilli.