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At least 721 records · Page 40Linked to original sources
PubMed2006

Does aflatoxin as an environmental mycotoxin adversely affect the renal and hepatic functions of Egyptian lactating mothers and their infants? A preliminary report.

BACKGROUNDS/AIMS: Aflatoxin as a mycotoxin constitutes a real human threat. Its presence in human milk was previously reported in different countries. This work is the first Egyptian report that aimed to assess the presence of aflatoxin in both mothers' milk and the infants' sera and studied its correlation with infants' kidney functions. METHODS: Fifty healthy breast lactating mothers and their infants who were exclusively breast fed for at least 4 months were included. All of them were subjected to thorough laboratory evaluation including determination of aflatoxin concentration by high performance liquid chromatography. RESULTS: Twenty-four mothers (48%) and their infants had been contaminated with aflatoxin with the following mean contamination levels (ng/ml); mothers' serum of 8.9+/-4.2, mothers' milk of 1.9+/-0.6 and infants' serum of 1.8+/-0.9. The presence of this contamination level is not associated with renal or hepatic dysfunction. CONCLUSION: Mothers and their infants in our locality showed a relatively high aflatoxin contamination rate. We did not find a correlation of this contamination level and either renal or hepatic dysfunction.

Adult↗
PubMed1982

Actions of a tremorgenic mycotoxin on amino acid transmitter release in vivo.

The tremorgenic mycotoxin verruculogen was administered directly into the brain of freely moving rats by the use of cannula systems that superfused either the cortical surface or the lateral ventricular space. The tremor produced by these CNS routes was compared with that produced by i.p. administration of the toxin or the dried mycelium of the fungus that synthesizes the verruculogen. The nature and degree of tremor produced by the central vs peripheral routes suggest that the site of action of verruculogen is not immediately adjacent to the cannula sites in the brain. Measures of the amino acids in the superfusates collected during the verruculogen-induced tremor showed an increase in the excitatory neurotransmitters, glutamate and aspartate in superfusates from the lateral ventricle but not in superfusates from the cortical surface. The differential effect on transmitter release suggests that a subcortical action of verruculogen is responsible for its tremorgenic activity.

Amino Acids↗
PubMed1976

Mechanism of the inhibition of transcription by PR toxin, a mycotoxin from Penicillium roqueforti.

PR toxin, a mycotoxin synthesized by Penicillium roqueforti, impairs the transcriptional process in liver cells; the two main RNA polymerase systems (enzymes A and B) are affected by PR toxin. The toxin does not require an enzymic conversion before interfering with in vitro RNA synthesis. Addition of ammonium sulphate completely prevents the inhibition of transcription by PR toxin. In vitro results, using RNA polymerase purified from E. coli, suggest that PR toxin impairs the activity of the RNA polymerase itself. Regarding the step of the transcription process affected, it is shown that PR toxin inhibits both initiation and elongation of the polynucleotide chain.

Amanitins↗
PubMed1975

[Investigations on the production of mycotoxins and their quantitative evaluation. I. The production of penicillic acid by Penicillium cyclopium (author's transl)].

A convenient thin-layer chromatographic screening procedure for the analysis of mycotoxins produced by Penicillium cyclopium is described. The production of penicillic acid is followed during a growth period of 44 days at two different temperatures. Quantitative evaluation is performed by UV densitometry at 234 nm. A biological profile is recorded showing the different ratios of four metabolites produced by Penicillium cyclopium and the definite effect of the growth temperature on the formation of penicillic acid in relation to the other metabolites.

Caproates↗
PubMed1995

Liquid chromatographic determination of the mycotoxin fumonisin B2 in physiological samples.

The fungus Fusarium moniliforme produces a group of mycotoxins, the fumonisins, of which the most abundant are fumonisins B1 (FB1) and B2 (FB2). Previously developed analytical methods for the determination of FB1 in physiological samples have been modified for the determination of FB2 by the use of less polar extraction solvents. Plasma and urine extracts were purified on strong anion-exchange solid-phase extraction cartridges and fecal extracts on reversed-phase (C18) cartridges. FB2 in purified extracts was determined by reversed-phase HPLC with fluorescence detection using performed o-phthaldialdehyde derivatives. These methods were reproducible (R.S.D. of less than 6%) with recoveries greater than 85%. In a short preliminary study, they have been applied to the determination of the fate of FB2 dosed to rats by gavage. Of the dose given to the animals, over 90% was recovered unmetabolised in the feces within 48 h.

Animals↗
PubMed1987

Studies on mechanisms of diarrhea induced by fusarenon-X, a trichothecene mycotoxin from Fusarium species: fusarenon-X-induced diarrhea is not mediated by cyclic nucleotides.

Cardinal signs of red mold toxicosis in man and farm animals are vomiting, nausea, diarrhea, and food refusal. The red mold toxicosis has been suggested to be induced by trichothecenes, which are produced by Fusarium fungi. Fusarenon-X (F-X) is one of the trichothecene mycotoxins. The ip injection of F-X to rats causes an expansion of the small intestine and watery diarrhea. In this study, we measured the concentrations of protein, sodium, potassium, and calcium in the serum of rat treated with F-X for the sake of demonstrating the loss of serum protein and the decreases of serum sodium and calcium by F-X. Since it is well known that some diarrheal diseases are due to the increase of cyclic nucleotide level in the intestinal mucosa, we also measured cyclic AMP and cyclic GMP levels in the intestinal mucosa. It was demonstrated that F-X did not increase the cyclic AMP and cyclic GMP levels in the jejunal and the ileal mucosa at 8 and 24 hr after F-X treatment. The results obtained in this work suggest that F-X-induced diarrhea is not mediated by the cyclic nucleotide system.

Animals↗
PubMed1987

Characteristics of inflammation induced by fusarenon-X, a trichothecene mycotoxin from Fusarium species.

Fusarenon-X (F-X) is one of the trichothecene mycotoxins, which have been suggested to induce Fusarium mycotoxicoses. Administration of F-X to experimental animals causes diarrhea, skin irritation, and foot edema. In the present work the properties of F-X-induced inflammation were examined. F-X increased capillary permeability of the abdominal blood vessels in a dose-dependent manner in mice. The F-X-induced increase of the abdominal capillary permeability was not inhibited by 200 mg/kg po of phenylbutazone, 200 mg/kg po of aspirin, 40 mg/kg po of phentolamine, 50 mg/kg po of diphenhydramine, 100 mg/kg po of dibenzyline, 200 mg/kg of hydrocortisone, and 4 mg/kg sc of reserpine. These results suggest that the permeability increment by F-X may not be mediated by serotonin, histamine, norepinephrine, prostaglandins, leukotrienes, and thromboxanes. The increment by F-X also appears to result from histological changes in the capillary blood vessels which are possibly induced by F-X-induced inhibition of protein synthesis, and/or from unidentified inflammatory chemical mediators.

Abdomen↗
PubMed1992

Fate of a single dose of the 14C-labelled mycotoxin, fumonisin B1, in rats.

The fate of the mycotoxin, fumonisin B1, (FB1) dosed to rats by i.p. injection and by gavage was traced using 14C-labelled FB1. Twenty-four hours after i.p. injection, 66% of the radioactivity was recovered in faeces, 32% in urine, 1% in liver and trace amounts (less than 1%) in kidney and red blood cells. When dosed by gavage, all (101%) radioactivity was recovered in faeces and trace amounts were found in urine, liver, kidney and red blood cells. The bulk of the radioactivity recovered was unmetabolized FB1.

Animals↗
PubMed1992

Occurrence of the mycotoxin chlamydosporol in Fusarium species.

The mycotoxin chlamydosporol (C11H14O5) has been independently isolated from three different Fusarium species (F. chlamydosporum, F. acuminatum and F. culmorum), suggesting that its distribution may be widespread. We have developed a sensitive, specific fluorometric assay for chlamydosporol that allows quantitation in crude culture extracts. Using this assay we have observed production of chlamydosporol on rice medium by 23 of 40 isolates (58%) of Fusarium sp. examined in amounts as high as 0.8% (wt/wt) dried culture medium.

Culture Media↗
PubMed1993

Biological activities of fumonisins, mycotoxins from Fusarium moniliforme, in jimsonweed (Datura stramonium L.) and mammalian cell cultures.

Fumonisins A1, A2, B1, B2 and B3 are a series of mycotoxins produced by strains of Fusarium moniliforme. Fumonisins are hydroxylated long-chain alkylamines esterified with propanetricarboxylic acid moieties that represent approximately half the mol. wt of the toxins. The A-series fumonisins are N-acetylated, whereas the B series contains free amino groups. Hydrolytic removal of the propanetricarboxylic acid moieties from fumonisins B1 and B2 yields the corresponding aminopentols, AP1 and AP2, respectively. These compounds were tested for toxicity on widely differing bioassay systems, representing plant and animal systems. The plant bioassay system employed jimsonweed (Datura stramonium L.) leaves and leaf discs in which toxicity was detected as electrolyte leakage, photobleaching and quantitation of chlorophyll reduction. The animal bioassay system employed cultured mammalian cell lines in which toxicity was detected as inhibition of cell proliferation. Fumonisins B1, B2 and B3 at 50 micrograms/ml or less were effective toxins after exposure periods greater than 24 hr in all plant and animal bioassay systems examined, except 3T3 mouse fibroblasts, whereas fumonisins A1 and A2 exhibited little or no activity. However, the hydrolytic degradation products AP1 and AP2 exhibited toxicity similar to or greater than B-series fumonisins in all test systems, including substantial toxicity to 3T3 mouse fibroblasts.

Animals↗
PubMed1996

Fumonisins, mycotoxins of increasing importance: their nature and their effects.

The fumonisins (FBs) are a group of closely related mycotoxins that are prevalent in maize. They were isolated from strains of Fusarium moniliforme (Sheldon), which were implicated in the aetiology of human oesophageal cancer in the Transkei, South Africa. Their discovery explained the cause of equine encephalomalacia, or "hole in the head" syndrome, when it was found by feeding trials in horses that they elicited the disease. Subsequently, they were found to cause hepatic cancer in rats and pulmonary oedema in pigs, with most animal species tested showing liver and kidney damage. FB1 is the most important of the group and, although poorly absorbed from the gastrointestinal tract, its action is at the cellular level, affecting sphingolipid metabolism. Ceramides derived from sphingosine metabolism are cell regulatory factors affecting, among other things, DNA synthesis. Because FB1 has a close molecular resemblance to sphinganine, it interferes with ceramide biosynthesis and, hence, the processes that it regulates, which is thought to explain its carcinogenic properties. Studies on the FBs are still at a relatively early stage, but it is already clear that they play an important role in animal mycotoxicoses and, by implication, in human disease. A more positive aspect is that they will be used in elucidating the role of sphingolipids in cellular regulation.

Animal Diseases↗
PubMed1980

Induction of cross-links between DNA and protein by PR toxin, a mycotoxin from Penicillium roqueforti.

PR toxin, a mycotoxin from Penicillium roqueforti, induces DNA--protein cross-links in chromatin of both cultured cells and isolated rat-liver nuclei. The presence of the aldehyde group in the PRT molecule is required for the induction of cross-linking; methylene bridges between nucleic acid and protein are presumably involved in the complex formation. The role of other functional groups of PR toxin is discussed.

Animals↗
PubMed1988

Mycotoxin production by molds isolated from 'Greek-style' black olives.

Seventeen mold strains were isolated from 'Greek-style' black olives produced in Morocco. Eight of these isolates were identified as Aspergillus flavus, seven as Aspergillus petrakii, and two as Aspergillus ochraceus Wilhelm. The A. flavus strains were tested for production of aflatoxins B1, B2, G1, and G2; and A. ochraceus and A. petrakii strains were tested for production of ochratoxin, penicillic acid, patulin, and citrinin. The organisms were tested for mycotoxin production on five different substrates, including rice powder-corn steep agar, autoclaved rice, yeast-extract sucrose broth (YES), potato dextrose agar (PDA), and fresh olive paste. All strains of A. flavus produced aflatoxins on all substrates except olive paste and PDA. In PDA, only two strains produced Aflatoxin B1. Five A. ochraceus group isolates produced penicillic acid on one or more of the substrates, but only two out of the five produced penicillic acid on olive paste. None produced ochratoxin, patulin or citrinin. Quantities of aflatoxin B1 produced in rice ranged from 5 to 14 micrograms/g of rice, and of penicillic acid 15-32 micrograms/g of rice. In olive paste, the concentrations of penicillic acid were 11.4 and 30.2 micrograms/g. Biological toxicity of extracts of mold cultures was confirmed using chicken embryos and a microbiological test. Crude extracts of cultures were also tested for mutagenicity using the Salmonella mutagenicity (Ames) Test, and some gave positive mutagenic responses.

Animals↗
PubMed1993

Bioassay of mycotoxins using terrestrial and aquatic, animal and plant species.

The role of bioassay in the diagnosis of mycotoxicoses in farm animals is discussed. Methods for detecting mycotoxin contamination of animal feeds using biological species (aquatic and terrestrial animals and plants but excluding bacteria and yeast) are reviewed. Factors that need to be considered when choosing and using particular bioassay procedures in a feed-screening programme are discussed in relation to the occurrence of false positives and false negatives.

Animal Feed↗
PubMed1994

Interaction of 14C-labelled fumonisin B mycotoxins with primary rat hepatocyte cultures.

An in vitro study on the interaction and biotransformation of the [14C]fumonisin B mycotoxins was conducted, using primary rat hepatocyte cultures and subcellular enzyme preparations. At the same concentration, fumonisin B2 (FB2) exhibited a higher cytotoxicity and specific binding to primary rat hepatocytes than fumonisin B1 (FB1). However, if the effective dose level (EDL) is considered (i.e. the lowest level of toxin that binds to the hepatocytes to elicit a cytotoxic effect), FB1 and FB2 exhibited a similar cytotoxic effect. FB1 was found to be associated with both the soluble and insoluble compartments within the cell. As assessed by the radioactivity associated with the cellular preparations, very little (approximately 0.01%) FB1 and/or FB2 bound to hepatocytes. In the subsequent fractionation of the culture medium using amberlite XAD-2 and silica-gel chromatography, no metabolites were detected, indicating that the fumonisin molecule was not metabolized by primary hepatocytes. The latter aspect was confirmed by the fact that incubation of FB1 with microsomal enzyme preparations also failed to indicate any metabolism of the fumonisins by the esterases or by cytochrome P-450 monooxygenase. FB1 was also found not to be a substrate for the triglyceride hepatic endothelial lipase, nor for a lipase from porcine pancreas. This study supports further the hypothesis that the intact molecule of the fumonisins is required for biological activity.

Animals↗
PubMed1994

Biliary excretion of the mycotoxin fumonisin B1 in rats.

The biliary excretion of the mycotoxin fumonisin B1 (FB1), produced by the fungus Fusarium moniliforme Sheldon, has been measured in male Wistar rats. After ip injection of a solution of FB1 (7.5 mg/kg body weight), 67% of the applied dose was recovered in bile over a 24-hr period, 88% of this recovery being excreted in the first 4 hr after dosing. In contrast to these results, a similar dose of FB1 given by gavage resulted in only 0.2% recovery of the toxin in bile over a 24-hr period. Hence, although these results show that biliary excretion is a major route of elimination of FB1 from the circulation, only small amounts of the toxin appeared to be absorbed from the gut in rats.

Animals↗
PubMed1986

Development of sensitive bacterial tests, exemplified by two mycotoxins.

For a sensitive bacterial test for mycotoxins the cup plate assay, based on growth inhibition, was optimised with Bacillus thuringiensis as test strain. Bacillus thuringiensis allowed the detection of 1.25 microgram kojic acid. A minimal amount of 12.5 micrograms kojic acid or 1.25 micrograms patulin was detectable by means of pigment suppression with isolated mutants of Serratia marcescens, whereas the wild type of this strain was insensitive.

Bacillus thuringiensis↗