The effects of the trichothecene mycotoxins, T-2 toxin, diacetoxyscirpenol and neosolaniol, on plaque formation by herpes simplex virus type 2 (HSV-2) in HEp-2 cells were determined. The 50% inhibitory concentrations for plaque production by HSV-2 were 2.3 ng/ml for T-2 toxin, 2.6 ng/ml for diacetoxyscirpenol, and 57.0 ng/ml for neosolaniol. Neither virus replication nor synthesis of virus-specific polypeptides was observed in the cells treated with the trichothecenes at concentrations completely inhibiting plaque formation. Plaque formation by HSV-2 was not inhibited by treatment of the cells with the trichothecenes for 1 hr postin-fection or for 15 hr before infection. These results indicate that the trichothecenes can affect HSV-2 in the stage of viral protein synthesis after infection, but not in the stage of virus adsorption to the host cells.
Moisture contents of maize kernels varied from 30.7 to 16.8%, depending on the harvesting times. Inoculated Aspergillus flavus failed to grow in the kernels of which the moisture content was less than 17%. The kernels of which initial moisture contents were about 21-31% were allowed to accumulate aflatoxins within a short time after the inoculation, and the toxin level was highest in the kernels harvested at 113 days after planting. From the field, airborne A. flavus was rarely detected. On the soil in maize field, the earlier in harvesting time, the more A, flavus was detected (max. 2, 180 cfu/g of the soil).
The population of Aspergillus flavus and the amounts of aflatoxins in maize ears and kernels collected from 4 areas in Thailand in 1987 were studied. Eleven maize ear samples from the randomly selected fields showed no infection of A. flavus and very low amount (9 ppb) of aflatoxin B1 was found in only one sample. Similarly, the infection of A. flavus in 6 maize ear samples collected from farmers' and middlemen's storages was very low (0-3% of kernels from the ear); two samples of them were positive for aflatoxins (aflatoxin B19 and 58 ppb). However, all 15 maize kernel samples collected from the middlemen's storages were found to be highly contaminated with A. flavus and aflatoxins. There were clearly less contaminations of A. flavus and aflatoxins in the maize ear than those in the kernels.
Emestrin, a new epidithiodioxopiperazine mycotoxin isolated from Emericella species, was examined for the effects on mitochondrial structure and function using isolated rat liver mito-chondria to gain an insight into the molecular mechanism of its in vivo toxicity. Emestrin was found to inhibit the ATP synthesis in mitochondria, exerting an uncoupling effect on oxidative phosphorylation in mitochondria. Emestrin was further observed to elicit a marked swelling of mitochondria in the isotonic KCl solution at the significantly lower concentrations than those for its uncoupling effect on oxidative phosphorylation. These results show a good agreement with the results in vivo toxicity test using rats and mouse, in which mitochondria were significantly impaired showing a drastic structural deformation (swelling) in liver and heart, which strongly suggests a direct toxic action of emestrin on mitochondria in vivo.
A total of 72 traditional herbal drugs from retailed stores in Indonesia was surveyed for aflatoxin contamination. Results of the TLC and HPLC analyses showed that two were aflatoxin positive. The levels of aflatoxin contamination were 7 ng B1/g and 1 ng B2/g in Selasi bi ji (Ocimum basilicum L.), and 10 ng B1/g and 1 ng B2/g in Kenari (Canarium amboinense Hochr.), respectively.
A foodborne disease outbreak due to consumption of fish in suburbs of Bombay during November 1987 was investigated. A total of 132 persons (80 males and 52 females) were affected, among whom 4 persons had died. The case history was available for only 38 persons and the symptoms included vomiting (97.3%) and only drowsiness (2.63%). Based on epidemiological, clinical, analytical and toxicological studies in mice it was concluded that the disease outbreak had possibly occurred due to the consumption of fish (Mystus seenghala) caught from a nearby fresh water pond which might have become toxic due to ingestion of algal toxins. The toxins have been formed in the pond as a result of ecological imbalance due to partial filling up during the preceding month which was earlier polluted heavily by the discharge of effluents from industries.
Interactions of AFB1 and DHBV, both of which are known to be carcinogenic to the livers, were analyzed in vitro. Primary hepatocyte cultures were performed using a duckling infected with DHBV. AFB1 was added continuously to the culture media at a concentration of 0.1 or 1.0 ng/ml, and the cells were cultured for a month. Spot hybridization of the culture media did not reveal any significant difference in the amount of DHBV-DNA between AFB1 administra-tion groups and control group. However, AFB1 administration increased numbers of particles and antigen of DHBV within the cultured hepatocytes. It was suggested that AFB1 gave some influence on replication and expression of DHBV.
We prepared an anti-T-2 toxin (T-2) monoclonal antibody (mAb) and developed the mAbbased ELISA for T-2. The ELISA was applied to analyze for T-2 in cereals and cereal products, and the resulted data were confirmed by GC/MS. Seventy-two out of 540 samples collected from 11 countries were positive for T-2 contamination with a range of 0.8-2, 000 ng/g. The T-2 positive samples were the highest in oat (55%), followed by corn (22%), barley (11%), rye (10%), wheat (9%) and rye flour (8%).