Two activities involved in terminal pathway conversion of sterigmatocystin to aflatoxin B1 were isolated from an aflatoxin-nonproducing mutant of Aspergillus parasiticus (avn-1), and the time course of appearance of the activities in culture was determined. Subcellular fractionation of fungal mycelia resolved the two activities into a postmicrosomal activity which catalyzed conversion of sterig...

Administration of aflatoxin B1 (AFB1) to rats resulted in the urinary excretion of 2,3-dihydro-2-(N7-guanyl)-3-hydroxyaflatoxin B1. This is the major product formed by the interaction in vivo of AFB1 with rat liver nucleic acids. The adduct was isolated from urine by the combined use of preparative and analytical high-pressure liquid chromatography and was quantitated by measurement of absorban...

A study of the effect in rats of dichlorodiphenyl trichloroethane (DDT) on hepatocarcinogenesis that is initated by aflatoxin B1 (AFB1). In the first experiment, Buffalo rats were given a single oral dose of AFB1 (5 mg/kg) followed by dietary DDT (100 ppm) for 20 weeks. Neoplastic nodules were observed in 1 of the 14 AFB1-exposed rats, compared with 3 of the 19 rats in the AFB1/DDT group. In th...

Single intramuscular injections of aflatoxin B1 into the tail muscle of Penaeus stylirostris produced 24- and 96-h median lethal doses of 100.5 (78.3 to 129.0) and 49.5 (29.8 to 82.3) mg/kg, respectively. A toxicity curve showed no threshold at the levels tested. The mortality response in a feeding study with P. vannamei was not dose dependent, but tissue and organ damage were similar to that s...

Hepatocellular carcinoma (HCC) is the fifth most common cancer worldwide and represents the third cause of mortality among deaths from cancer (Semela & Heim, 2011; EI-Serag & Rudolph, 2007; Yuen et al, 2009; Lodato et al, 2006; Hainaut & Boyle, 2008). There are upwards of 600, 000 new cases each year in Asia and sub-Saharan Africa, where populations suffer both from a high prevalence of hepatit...

Wild-type Aspergillus parasiticus produces, in addition to the colorless aflatoxins, a number of pigmented secondary metabolites. Examination of these pigments demonstrated that a major component was an anthraquinone, averufanin. Radiolabeling studies with [14C]averufanin showed that 23% of the label was incorporated into aflatoxin B1 by the wild type and that 31% of the label was incorporated ...

2,3-Dihydro-2,3-dihydroxyaflatoxin B1 (dihydrodiol) was formed as a major metabolite in the incubation of aflatoxin B1 with rat and hamster liver microsomes. The yield of the dihydrodiol was maximal at pH 6.5, was reduced nicotinmide adenine dinucleotide phosphate- and cytochrome P-450-dependent, and was increased 2- to 4-fold by pretreatment of the animals with phenobarbital; pretreatment with...

The biflavonoids 6,6"-bigenkwanin, amenthoflavone, 7,7"-dimethoxyagastisflavone and tetradimethoxybigenkwanin isolated from Ouratea species were tested for inhibitory activity on Aspergillus flavus cultures. Suspensions of Aspergillus flavus spores were inoculated into 50 ml of YES medium at different biflavonoid concentrations: 5 and 10 microg/ml for 6,6"-bigenkwanin, amenthoflavone and 7,7"-d...

Accepted: 21-03-2015 The known mycotoxin the most important which have been studied mostly because of possible hazards to human health are the afltoxins.Aflatoxins produced very commonly by two species of Aspergillus viz. Aspergillus flavus and Aspergillus parasitic. In this study growth pattern and culture characteristics of Aspergillus flavus isolates were studied. Twelve strains of A. flavus...

The metabolism of aflatoxin B, has been investigated in male rhesus monkeys given i.p. injections of a mixture of ring-labeled aflatoxin B!-'4C and nonradioactive toxin, at a total dose of 0.4 mg/kg. Thirty-five % of the administered radioactivity was excreted in urine within 96 hr. The excretion rate reached a maximum 1 hr after dosing and then fell rapidly, but urine excreted after 96 hr stil...