The production of aflatrem and its related indoloditerpene metabolites by microsclerotium-producing strains of Aspergillus flavus was investigated. Four strains of atypical A. flavus isolated from Indonesian traditional medicines (native name, “Jamu”) and three representative strains of the same fungus obtained from the Northern Regional Research Center, USDA were cultured on Czapek-Yeast extract Agar at 34°C and the amounts of tremorgenic mycotoxins, aflatrem and seven related indoloditerpenes, were measured by high-performance liquid chromatography with a UV detector. All the strains examined produced aflatrem and dihydroxyaflavinine. The concentrations of them were ranged from 149 to 3, 009 and 1, 092 to 35, 629μg/g of the dried sclerotia, respectively. Aflavinine, monohydroxyaflavinine, monohydroxyisoaflavinine, paspaline, paspalinine and emindole SB were detected in the sclerotia of A. flavus. This is the first report on the production of emindole SB and paspaline by A. flavus.
The wheat grains with low amylographic viscosity values generally occurred under condition of high humidity after maturing stage of the developing wheat plant. Because Fusarium graminearum causes a disease (Fusarium blight or scab) of preharvest wheat and subsequently contaminates the grains with mycotoxins under similar environments, a relationship between the low amylographic viscosity values and the Fusarium-toxin contamination in wheat grains might be suspected. Therefore, in order to clarify on this problem, 36 imported and 16 domestic wheat samples were analysed for their maximum viscosity values and the amounts of two Fusarium-toxins, deoxynivalenol (DON) and nivalenol (NIV), which are most potent natural contaminants among numerous Fusarium-toxins. The results showed no significant relationship between the low amylographic viscosity values and the amounts of DON and NIV contamination in the wheat samples examined.
To clarify the detailed mechanism of preferential induction of male rodent liver cancer by aflatoxin B1 (AFB1), we investigated the effects of steroid hormones and inducers of cellular differentiation on the growth of Kagura-2 cells established from AFB1-induced rat hepatoma. By the addition of 10-5 M glucocorticoid (GC) hormones such as dexamethasone (DEX) and triamcinolone acetonide (TA), the colony formation of Kagura-2 cells in soft agar was stimulated about 16-fold of the control. Moreover, the cells showed the GC hormone-dependent growth in serum-free medium. In contrast, tamoxifen, sodium butyrate and N, N'-hexamethylene-bis-acetamide (HMBA) strongly inhibited the cell growth. Sex steroid hormones, estradiol and testosterone, slightly enchanced the cell growth. The present data obviously indicate that GC hormones play a critical role in the progression step of hepatocarcinogenesis by AFB1.
A survey for the occurrence of T-2 toxin in domestic and imported agricultural products, medicinal plant materials and barley-based drinks of Korea was conducted by using GC and GC/MS. Among 20 cereals and animal feeds, the cotton seed meal produced in China and one sample of wheat imported from Canada showed a contamination of T-2 toxin at a concentration of 6, 000 ng/g and 7, 500 ng/g, respectively. None of the medicinal plant materials or barley-based drinks were found to be contaminated with T-2 toxin within the detecting range of the method employed