Aspergillus flavus infection of peanut seeds before harvest was examined at ICRISAT located in the suburbs of Hyderabad, India. None of three peanut cultivars in two different soil-type fields were invaded with A. flavus in both post rainy and rainy season experiments. A result of examination of A, flavus infection in farmers' peanut samples harvested in rainy season was also presented.
In 0.5% caffeine-containing yeast extract-sucrose (YES) broth, the growth of 49 strains of aflatoxigenic and non-aflatoxigenic Aspergillus flavus and A, toxicarius which were isolated from peanuts, spices and green coffee beans was compared at 25°C after 7 days incubation. Although all strains from the peanuts and spices could not grow well on the caffeine-containing YES broth, the growth of three aflatoxigenic strains and one non-aflatoxigenic A, flavus from the green coffee beans was little affected (growth rate: 36.5-54.8%). These strains were confirmed as a caffeine-resistant, by further detailed experiments. Namely, the effects of caffeine on growth and aflatoxin production by the strains and residual caffeine in their culture filtrates were observed on the 0.5% caffeine-containing YES broth at intervals of 5 days in the period of 20 days. For the first 5 days, the growth of these strains was delayed by the addition of caffeine, but the growth was completely recovered after the 10 days. Aflatoxin production of one strain of A, flavus was inhibited by caffeine, but the two other strains produced a high level of aflatoxin B1 in the 0.5% caffeine-containing YES broth, reaching about the same or more amounts as the control after the 15 days of incubation. The added caffeine in the culture of these caffeine-resistant strains was degraded in the range of 10-91%.
The effect of Bacillosporin A, from Taralomyces bacillosporus, on oxidative phosphorylation in mitochondria was examined. Bacillosporin A was found to uncouple the oxidative phosphorylation, causing 50% uncoupling at 5-7 μM, and to depress the state 3 respiration, causing 50% inhibition at 20 μM. Bacillosporin A inhibited the oxygen uptake of electron transport particles (ETP) oxidizing succinate, causing 50% inhibition at about 70 μM. But none of succinic dehydrogenase, succinic-cytochrome c reductase, and cytochrome c oxidase were speciffcally and strongly inhibited by this compound.References
The effects of T-2 toxin on the infection of Japanese encephalitis (JE) virus were examined in the vaccinated and the non-vaccinated mice. 1) In the non-vaccinated mice, when they received 2mg/kg of T-2 toxin intra peritoneally 6 times every other day before intracerebral injection of JE virus, all of them died within 5 days after the JE virus infection, while only three of ten mice of non-treat ment with T-2 toxin died more slowly by the JE virus infection during the period of ob-servation. 2) In the vaccinated mice, similar pretreatments with T-2 toxin before vaccination also caused early death of mice after the JE virus infection. The early death of JE virus infected mice suggests that T-2 toxin impairs some natural defense mechanism. 3) Neutralization antibody titers of the pooled sera from vaccinated and T-2 toxin treated mice were compared with titer of the pooled sera from non-treated with T-2 and vaccinated mice. There was no significant difference between them. 4) The growth of JE virus in chick embryo cells was completely inhibited when more than 10 ng/ml T-2 toxin was present in the culture medium. The synthesis of JE virus specific RNA was not affected with T-2 treatment in the early stage of the infection (from 3 hr to 6 hrs) but was inhibited with T-2 treatment in the late stage of the infection (12 hrs).
In the previous paper (Proc. Jpn. Assoc. Mycotoxicol. 19, 34 (1984)), the authors described the chemical analyses of deoxynivalenol (DON), nivalenol (NIV) and fusarenon-X in cereals. In this paper, we have revised the method in regards to shortage of analytical time. The cleanup with Florisil column (method A) is enough for quantitative determination of DON and NIV higher than 10 ppb. For determination of the toxins less than 10 ppb, further cleanup step using Sep-pak column (method B) was required. The present method B was applied to 30 samples of wheat, barley and corn. Both DON and NIV were detected in 13 samples of domestic cereals. DON alone was detected in 7 samples of corn imported from U.S.A.. As a whole, natural occurrence of DON and NIV were 80% of cereals tested.
From the 20 soil samples collected at date-plantation in Iraq, 56 molds were isolated. The fungal species were Aspergillus flavus, A, caespitosus, A, fumigatus, Emericella nidulans, E, variecolor, E, acristata, Chaetomium spp., and the other Ascomycetes and Deuteromycetes. The lethal toxicity of ethyl acetate extracts of the moldy rice was ex amined by intraperitoneal injection to mice. Many of the molds were found to be toxigenic. By TLC analysis, the productivity of aflatoxin, sterigmatocystin, asteltoxin, verruculogen and fumitremorgin was confirmed on some of the isolates. A new toxic metabolite, tentati vely designated as EQ-1, was isolated from Emericella quadrilineata strain No. 83-Ir-4-7.
The ultrastructure of mitochondria of murine heart muscles and those of the hepatocytes were investigated after administration of asteltoxin, a secondary metabolite of Emericella variecolor, in in vivo and in vitro systems. In both systems, the mitochondria of the heart muscle were more susceptible to asteltoxin than those of the hepatocytes.
ICR female mice of 3 weeks old after birth were fed with diet containing 50 or 100 ppm zearalenone between 3 and 8 weeks of age. Vaginal opening was hastened, followed by continuous estrous phase with vulval swelling for 1 and 2 weeks in 50 and 100 ppm group, respectively. The uterus was enlarged with the hyperplastic endometrium. The ovary was small and the number of corpora lutea was smaller than controls. These findings were normalized after 5 weeks, despite of continuous ingestion of zearalenone. Among the treated female mice, fetal death and/or premature delivery was observed after the mating with control males. These results indicate estrogenic effects of zearalenone on mice as reported on pigs.