Tomomasa Misato

A simple procedure for the preparation of UDP-N-acetylglucosamine-14C.

A simple, efficient method is described for the preparation of UDP-N-acetylglucosamine (UDP-GlcNAc)-14C. D-Glucosamine-14C is first incubated with growing mycelia of the fungus Helminthosporiumsativum in the presence of polyoxin D, an inhibitor of the chitin synthetase of fungi. The sugar nucleotide is then isolated from the incubation mixture by paper electrophoresis and paper chromatography. The overall yield of the radioactivity in UDP-GlcNAc-14C is about 65% of the dose of glucosamine-14C added.

Studies on the Screening Methods of the Chemicals for Bacterial Leaf Blight of Rice Plant

Comparative investigation was taken among several antibacterial screening methods for controlling bacterial leaf blight of rice plant caused by Xanthomonas oryzae with 5 chemicals applying nowadays. In the agar dilution method, the agar diffusion method and the turbidimetric method, Phenazine-5 N-oxide, Cellocidin and Chloramphenicol were remarkably effective, whereas, Ni-bis-dimethyldithiocarbamate was a little effective, and Fentiazon was not observed the antibacterial activity in these tests. In rice seedling screening methods, the high protective effects of these five chemicals were observed by 3 kinds of method, which were needle inoculation, bacterial exudation, and spray inoculation methods. The results were concluded that the method of spraying chemicals immediately after needle inoculation was preferable as primary screening test and the other methods might be applied as secondary screening test.

Application of antibiotics to agricultural chemicals

The 140 antifungal actinomycetes, which had been selected from 7243 strains in Tokyo University, were tested in our laboratory in relation to their antifungal activity against seven plant pathogens; Piricularia oryzae Bri. et Cav., Ophiobolus miyabeanus Ito et Kuribayashi, Gibberella saubinetii (Mont.) Sacc., Ceratostomella fimbriata (E. et H.)Ell., Alternaria kikuchiana Tanaka, Glomerella cingulata Spauld. et Schr., and Fusarium lini Bolley. As shown in Tabe I, many actinomycetes showed strong inhibitory action against one or more of the seven test plant pathogens in of 12 strains agar disc diffusion tests. The antifungal spectra of actinomycetes, which were found to be highly effective on P. oryzae, are given in Table 2.The 40 strains of actinomycetes, which showed high antifungal activity on P. oryzae, were cultivated in shaken liquid modified Waksman media at 28°C. The antifungal activities of culture fiitrates at three and five days were tested by cup method. Data obtained are given in Table 3. Twelve strains were selected on the basis of the size and clearnesss of the inhibition zone around the cup.The effect in vivo of 12 strains, which were found to be effective in vitro on rice blast fungus, were studied in greenhouse tests. As shown in Table 4, the culture filtrates were found by slidetests to be capable of inhibiting the germination of conidia. Rice plants showed an increase in resistance to the rice blast when cultured in water added with filtrates of actinomycetes culture at two to seven days or sprayed with diluted filtrates. The number of leaf-spots were remarkably less than in the untreated plants, as shown in Table 5 and 6.As the result of these tests, two active strains were selected as the most promising anti-blast actinomycetes among the 140 strains.