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Biomedical subjects

H Kurata

Publications and source records attributed to H Kurata.

At least 181 records · Page 10Linked to original sources

Dermatophytosis of tiger caused by Microsporum canis.

Microsporum canis was isolated from the inflammatory skin lesions of a Bengal tiger in April, 1979. In clinical findings rounded area of alopecia, 3 to 8 cm in size was observed on the right haunch and the tail. The skin lesions were covered with thin scales, but the inflammatory changes were not severe. Findings, on physical examination, were unremarkable and the animal appeared healthy except for the skin lesions. The infected hairs were invaded by the fungal elements and arthroconidia were around the hair shaft. Cuticles and cortex of the infected hairs were brittle. They were evidently digested and were easily pulled out from the hair follicles. In mycological findings numerous and typical macroconidia were observed. By cross mating of a isolate from tiger and Nannizzia otae(-) strains, cleistothecia were produced. Both organic iodide and undecylenic acid ointment were effective for therapy. In this paper the dermatophytosis of tiger caused by M. canis is described.

Animals↗

Fungal contamination and mycotoxin-producing potential of dried beans.

A total of 604 samples of about 7 different types of beans was examined to determine their mycological profiles, and suitability for use as solid substrates for mycotoxin production. All of the samples were collected from bean jam makers in Tokyo by the official food examiners. Genera Penicillium and Aspergillus were predominant, and genus Wallemia was also found commonly in all types of beans. Mycotoxin-producing Aspergillus strains were isolated from 52 samples of beans, approximately 9% of the total. The highest incidence of toxigenic Aspergillus (14.1%) was found in kidney beans. Red beans and peas inoculated with Aspergillus ochraceus were found to produce about 7 to 8 times more toxin than was obtained in a liquid medium. and red beans inoculated with A. versicolor produced more toxin than was obtained in yeast extract sucrose broth. Green peas inoculated with Fusarium graminearum produced about 8 times more T-2 toxin than was obtained in 1% peptone containing Czapek solution under comparable culture conditions.

Aspergillus↗

Mycotoxin production by Chaetomium spp. and related fungi.

Screening for mycotoxin production by Chaetomium spp. and related fungi on rice culture was conducted by a combination of cytotoxicity tests using HeLa cells and thin-layer chromatography. Producers of sterigmatocystin, O-methylsterigmatocystin, chaetochromin, chaetocin, chetomin, cochliodinols, and mollicellin G were found and the taxonomic significance of these findings is discussed.

Anti-Bacterial Agents↗

Inhibitory effects of spices on growth and toxin production of toxigenic fungi.

The inhibitory effects of 29 commercial powdered spices on the growth and toxin production of three species of toxigenic Aspergillus were observed by introducing these materials into culture media for mycotoxin production. Of the 29 samples tested, cloves, star anise seeds, and allspice completely inhibited the fungal growth, whereas most of the others inhibited only the toxin production. Eugenol extracted from cloves and thymol from thyme caused complete inhibition of the growth of both Aspergillus flavus and Aspergillus versicolor at 0.4 mg/ml or less. At a concentration of 2 mg/ml, anethol extracted from star anise seeds inhibited the growth of all the strains.

Aflatoxins↗

The production of chaetoglobosins, sterigmatocystin, O-methylsterigmatocystin, and chaetocin by Chaetomium spp. and related fungi.

Production of mycotoxins by Chaetomium spp. and related fungi on rice culture was examined by a combination of cytotoxicity tests using HeLa cells and thin-layer chromatography. Three species, C. mollipilium, C. rectum, and C. subaffine, as well as C. cochliodes and C. globosum, were proved to produce chaetoglobosins. From cultures of four strains of Chaetomium sp., assigned to C. thielavioideum, and one strain of Farrowia sp., chaetocin, sterigmatocystin, and O-methylsterigmatocystin were isolated. Morphological characteristics of the producers of sterigmatocystins are described.

Ascomycota↗

Hepatic changes in male ACI/N rats on low dietary levels of sterigmatocystin.

Three groups, each consisting of 36 male ACI/N rats, were fed a diet containing 10, 1, or 0.1 ppm sterigmatocystin for life span. There was no dose--effect relationship on tumor incidence or mean survival time. Toxic and preneoplastic changes of the parenchyma such as hyperplastic foci were observed in the liver of experimental groups with dose--effect relation, but hepatocellular carcinoma was observed only in one rat of 10 ppm group. In addition to these lesions, hemangiosarcomas of the liver were also observed in the highest and middle-dose groups, 3/26 and 1/29, respectively. There was not significant difference in the incidence of other tumors in experimental or control groups.

Animals↗

Differential mutagenicity of N-methyl-N-nitrosocarbamate insectides in Escherichia coli strains having different DNA repair capacities.

Four isogenic strains of Escherichia coli with the same auxotrophic marker (arg Fam--namely wild-type, uvrA-, polA- and recA-) were used for testing the lethalities and mutagenicities of 1-naphthyl N-methyl-N-nitrosocarbamate (nitroso-NAC), 3-methylphenyl N-methyl-N-nitrosocarbamate (nitroso-MTMC), and 3,4-dimethylphenyl N-methyl-N-nitrosocarbamate (nitroso-MPMC). The strains recA- and polA- showed a similarly higher sensitivity to killing than wild-type and uvrA- after treatments with each of the three chemicals, whereas the strains wild-type, uvrA-, and polA- were equally mutable by these compounds at equal doses. The strain recA- was hardly mutable by nitroso-NAC, but significant levels of Arg+ mutations were observed after treatments with nitroso-MTMC and nitroso-MPMC. These and previous results suggest that both nitroso-MTMC and nitroso-MPMC are similar in their mutagenicity pattern to N-methyl-N'-nitro-N-nitrosoguanidine whereas nitroso-NAC is similar to methyl methanesulfonate or X-rays, and that the major damage to DNA of the three agents is not excisable by the uvrA+-dependent excision repair, probably methylation in DNA.

Arginine↗