Isolation and cultivation of spore-forming filamentous bacteria from Porcellio scaber

An endospore-forming rod-shaped filamentous bacterium was taken from boiled intestines of common sow bugs (Porcellio scaber, isopod crustaceans). The bacteria were grown on peptone - yeast extract medium. As many as 180 cells per filament were counted in culture; filament length was a function of time after germination and oxic conditions. Cultures continued to grow filamentously after 10 successive transfers. The development of spores was inhibited by strict anaerobiosis for 3 months. Spore-forming filaments over 100 mu m long in fresh intestinal material were observed only in guts taken from sow bugs cultivated in darkness. Phenotypic tests presented here show this isolate to be a member of the genus Bacillus, most closely resembling B. cereus.