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The bacterium capable of efficiently digesting chitin was isolated from chitin-amended field soil. It was identified as Kurthia zopfii, and extracellular chitinases secreted into respective culture filtrates were electrophoretically analyzed using a polyacrylamide gel containing glycol chitin. The result indicated that K. zopfii produced the 72, 58, and 44 kilodalton chitinases. The gene (chiSH1) encoding chitinase was cloned from K. zopfii KI2-119 and the entire nucleotide sequence (2097 bases) was determined. In order to evaluate the feasibility of chitinolytic microbes on the protection of chitinous fungal diseases, viable cells of E. coli transformed with the chiSH1 were applied to barley leaves inoculated with the powdery mildew pathogen. The result indicated that the growth of the pathogen was effectively suppressed by the present treatment, suggesting the importance and effectiveness of chitinolytic microbes as a biocontrol agent.

A small rod, capable of formine crater-like plaques on lawns of Vibrio parahaemolyticus, was isolated from a marine environment. The isolate was a gram-negative straight rod with round ends and was small in size, equal to that of halophilic Bdellovibrio strain 5501. The isolate appeared to have close taxonomic relationships to Cytophaga, since this bacterium moved slowly in a gliding manner on a solid agar surface, hydrolyzed agar and starch, contained yellow pigment and was halophilic. The isolate was able to grow not only under host-dependent but also under host-independent conditions when low nutrient media were used for cultivation, and its bacteriolytic mode was different from that of Bdellovibrio, an endoparasite. The isolate was halophilic and required Mg++ and Ca++ in addition to 3% saline for growth. The isolate showed a broad host rnage when tested for plaque-forming activity on gram-negative bacteria but not on the gram-positive bacteria tested so far.