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PubMedDate not supplied

Occurrence of mycotoxins in cereals and animal feedstuffs in Natal, South Africa.

During the period 1982-1983, just under 800 samples of agricultural commodities, comprising cereals, compound feeds, hay, and silage, were examined for molds and mycotoxins. Aflatoxin B1 showed the highest incidence rate; it occurred in over 27% of all samples analyzed, the highest levels being found in peanut meal at 1500 ppb. Other mycotoxins detected were patulin and a number of trichothecene toxins at incidence rates in all commodities of 5.6 and 3.1%, respectively. The commodities at highest risk were oil seeds, excluding soya bean; the latter was found to be fairly free from contamination with mycotoxins. The most prevalent fungi were Aspergillus flavus and parasiticus, which were found in over 22% of all samples, whereas Penicillium spp. showed the lowest incidence of genera, specifically identified in 8.3% of all samples examined. This latter finding explains in part the low incidence of Penicillium mycotoxins.

Aflatoxin B1↗

PubMedDate not supplied

[Organization of the system of control of food contamination with mycotoxins].

Mycotoxins are secondary metabolites of microscopic fungi. They are classified with particularly hazardous contaminants of foods and feeds. It has been demonstrated that they are extremely dangerous for the health of man, widely spread and do considerable economic damage. The authors describe in detail the data as to the level of contamination of different foods with aflatoxins, ochertoxins, citrinin, patulin, trichotecenic mycotoxins, and zearalenone. The principal role in the prevention of human mycotoxicoses is played by the control over food contamination with mycotoxins. An organization program of the control has been developed. The principal feature of the program is the organization of the specialized scientific-practical centers responsible for the collection and summarization of the results of monitoring and for the development of prophylactic measures. The authors provide data on the maximum allowable concentrations of aflatoxins in foods validated in different countries. Review the topics concerned with the assessment of the efficacy of the control over food contamination with mycotoxins.

Aflatoxins↗

PubMedDate not supplied

Mycotoxins in grain dust: method for analysis of aflatoxins, ochratoxin A, zearalenone, vomitoxin, and secalonic acid D.

A multimycotoxin method is presented to quantitate aflatoxins, ochratoxin A, zearalenone, secalonic acid D, and vomitoxin in grain dust. Dust spiked with these mycotoxins was extracted sequentially with methylene chloride followed by acetonitrile-water (86 + 14). Vomitoxin was recovered in the latter extract and all other mycotoxins were recovered in the methylene chloride. Aflatoxins and ochratoxin were quantitated by fluorescence measurement on silica thin layer chromatographic plates. The other mycotoxins were quantitated after cleanup by reverse phase liquid chromatography and ultraviolet detection. Recoveries from dust spiked in the parts per billion (ng/g) range were approximately 80% (SD = 15-29%) for all mycotoxins. Minimum detectable amounts ranged from less than 0.5 ng/g for aflatoxins to 20 ng/g for zearalenone.

Aflatoxins↗

PubMed1981

Simultaneous detection of several Fusarium mycotoxins in cereals, grains, and foodstuffs.

A systematic method is described for the simultaneous determination of Fusarium mycotoxins (nivalenol, deoxynivalenol, fusarenon-x, diacetoxyscirpenol, neosolaniol, T-2 toxin, HT-2 toxin, butenolide, moniliformin, and zearalenone) in cereals, grains, and foodstuffs. Mycotoxins were extracted with aqueous methanol and purified by a 2-step chromatographic procedure using Amberlite XAD-4 and Florisil columns. The column eluates were concentrated and spotted on a thin layer chromatographic (TLC) plate which was then developed in CHCL3-methanol (93 + 7) and toluene-acetone-methanol (5 + 3 + 2). Each mycotoxin was quantitated by gas chromatography (GC) and TLC densitometry. The minimum detectable concentrations (microgram/kg) in various test materials were: nivalenol, deoxynivalenol, and fusarenon-x, 2.0; diacetoxyscirpenol, neosolaniol, T-2 toxin, and HT-2 toxin, 80; zearalenone, 10; butenolide, 30; and moniliformin, 50. Recoveries of the mycotoxins added to various cereal samples at 1.0-2.0 microgram/g were greater than 71% and averaged 85%.

Chromatography↗

PubMed1993

[Significance of mycotoxins for health--present and past].

Investigations from several European countries indicate that, in former days, there was a connection between mycotoxins, mortality and reduced birth rate. In addition to being acutely toxic, many mycotoxins can interfere with the immune system, even in small concentrations. While tuberculosis was declining in Norway as a whole around year 1900, it culminated in Finnmark county. In addition, infant mortality was high. These people in the North ate rye flour imported from Russia, and harvested, transported and stored under conditions which may have favoured growth of toxic fungi. The mycotoxin ochratoxin A has been surveyed in several countries. The level in human sera seems to indicate continuous, widespread exposure of humans to ochratoxin A. Mycotoxin contamination of food and feeds may be a health problem of unknown dimensions.

Food Contamination↗

PubMedDate not supplied

Application of immunoaffinity columns to mycotoxin analysis.

Immunoaffinity columns (IACs) are widely used for cleanup and isolation of mycotoxins extracted from foods and biological fluids, particularly aflatoxins, ochratoxin A, and fumonisins. The columns are prepared by binding antibodies specific for a given mycotoxin to a specially activated solid-phase support and packing the support suspended in aqueous buffer solution into a cartridge. The mycotoxin in the extract or fluid binds to the antibody, impurities are removed with water or aqueous solution, and then the mycotoxin is desorbed with a miscible solvent such as methanol. Further separation can be performed with IAC, followed by liquid chromatographic (LC) quantitation, either off-line or on-line in an automated system, or by fluorometry. IACs have been used by laboratories that developed the antibodies but are also available commercially for aflatoxins, ochratoxin A, fumonisins, zearalenone, and deoxynivalenol. Among commercial IACs, Aflatest P is used as the cleanup step in an LC method and in a solution fluorometry method for corn, peanuts, and peanut butter that was adopted as an AOAC INTERNATIONAL Official Method after evaluation by an international collaborative study. As part of a fluorometer-based test kit, aflatest P was further certified by the AOAC Research Institute to measure total aflatoxins in 10 grains and grain products. IACs can concentrate the analyte from a large amount of sample, allowing detection limits at low parts-per-trillion levels in some cases (e.g., for aflatoxin M1 and ochratoxin A in liquid food matrixes). Regeneration of IACs for reuse in aflatoxin, ochratoxin A, fumonisin, and zearalenone analyses has been investigated.

Aflatoxins↗

PubMedDate not supplied

Effects of T-2 mycotoxin on gastrointestinal tissues: a review of in vivo and in vitro models.

T-2 mycotoxin, a trichothecene, is the principal toxic component of Fusarium sp. Agricultural products and food are frequently contaminated with this toxin. Various animal models have been used to determine its metabolic fate, rate of excretion, and distribution. A modulation effect on cell-mediated immunity and alterations in gastrointestinal propulsion have been demonstrated. The toxin has been shown to produce some similar pathologic alterations in various animal species studied. The consistent alteration appears to mainly affect mitotic cells of the gastrointestinal tract and the lymphoid system. A host of bioassay systems are now being used as alternative methods to the use of animals for testing of the mycotoxin. These tests may accurately assess and define the role of the subject-toxin interactions following consumption of T-2 mycotoxin contaminated food sources. T-2 mycotoxin, as observed above with in vivo and in vitro models, promotes a chemically-induced change in structure and function of affected gastrointestinal cells from a transient and reversible aberration in a single enzymatic reaction to cell death. Regardless of the end point measured, the toxic response brought about in cells appears to involve the interactions of virtually all subcellular processes--membrane transport and permeability, chemical metabolism, DNA function, and energy production/expenditure--as cells attempt to maintain their functional integrity while disposing of the toxicant. The variation in the quality of the toxic response with dose suggests that more cellular processes are perturbed as the chemical dose is increased.

Animals↗

PubMed2001

The state-of-the-art in the analysis of type-A and -B trichothecene mycotoxins in cereals.

The aim of this review is to describe the state-of-the-art in the analysis of A- and B-trichothecene mycotoxins in cereals and to support knowledge and experience exchange between laboratories in the field of Fusarium mycotoxin analysis. Current screening tests and quantitative methods for the most prevalent type-A and -B trichothecenes, HT-2 and T-2-toxin, and deoxynivalenol (DON) are reviewed. This includes the extraction and clean-up procedures and chromatographic methods (TLC, HPLC, GC) applied and the immunochemical methods, especially enzyme-linked immunosorbent assay (ELISA), employed for the determination of these mycotoxins. Results from recent intercomparison studies of the determination of DON are also discussed. Experience gained during these intercomparisons clearly shows the need for further improvement in the determination of trichothecenes, to obtain more accurate and comparable results. This also indicates there is a strong need for the development of further certified reference materials (CRM) which would enable comparison of measurement results between different European laboratories for several A- and B-trichothecenes. For both A- and B-trichothecenes there is still a lack of simple and reliable screening methods enabling the rapid detection of these mycotoxins at low cost.

Chemistry Techniques, Analytical↗

PubMed1987

A homogeneous immunoassay for the mycotoxin T-2 utilizing liposomes, monoclonal antibodies, and complement.

The trichothecene mycotoxin T-2 is a fungal metabolite known to contaminate agricultural products and cause intoxication of humans and animals. We have developed a homogeneous competition inhibition assay for T-2 mycotoxin based on complement-mediated lysis of liposomes. The T-2 mycotoxin was converted to an acid chloride derivative, subsequently coupled to the amino group of phosphatidylethanolamine, and incorporated with the phospholipid into unilamellar liposomes. Carboxyfluorescein, which is self-quenched at high concentrations, was entrapped in the liposomes as a release marker. We used a monoclonal IgG1 antibody specific for T-2 mycotoxin and a polyclonal anti-mouse Ig as a secondary antibody since the anti-T-2 IgG1 does not activate complement. In the absence of free T-2, the liposomes were lysed within 30 min after the addition of complement, releasing carboxyfluorescein into the surrounding buffer. In the presence of free T-2 toxin, the binding of antibodies to the liposomes was reduced, causing a corresponding decrease in lysis. This assay proved to be sensitive to T-2 toxin levels as low as 2 ng, which is 10-fold more sensitive than the present enzyme immunoassay using the same antibodies.

Antibodies, Monoclonal↗

PubMed1990

In vivo effects of T-2 mycotoxin on synthesis of proteins and DNA in rat tissues.

Rats were given an ip injection of T-2 mycotoxin (T-2), the T-2 metabolite, T-2 tetraol (tetraol), or cycloheximide. Serum, liver, heart, kidney, spleen, muscle, and intestine were collected at 3, 6, and 9 hr postinjection after a 2-hr pulse at each time with [14C]leucine and [3H]thymidine. Protein and DNA synthesis levels in rats were determined by dual-label counting of the acid-precipitable fraction of tissue homogenates. Rats given a lethal dose of T-2, tetraol, or cycloheximide died between 14 and 20 hr. Maximum inhibition of protein synthesis at the earliest time period was observed in additional rats given the same lethal dose of the three treatments and continued for the duration of the study (9 hr). With sublethal doses of T-2 or tetraol, the same early decrease in protein synthesis was observed but, in most of the tissues, recovery was seen with time. In the T-2-treated rats. DNA synthesis in the six tissues studied was also suppressed, although to a lesser degree. With sublethal doses, complete recovery of DNA synthesis took place in four of the six tissues by 9 hr after toxin exposure. The appearance of newly translated serum proteins did not occur in the animals treated with T-2 mycotoxin or cycloheximide, as evidenced by total and PCA-soluble serum levels of labeled leucine. An increase in tissue-pool levels of free leucine and thymidine in response to T-2 mycotoxin was also noted. T-2 mycotoxin, its metabolite, T-2 tetraol, and cycloheximide cause a rapid inhibition of protein and DNA synthesis in all tissue types studied. These results are compared with the responses seen in in vitro studies.

Amino Acids↗

PubMed1987

Acute inhalation toxicity of T-2 mycotoxin in mice.

Experiments were conducted to study the acute inhalation toxicity of T-2 mycotoxin in both young adult and mature mice. For a 10-min aerosol exposure, the 24-hr LC50 of T-2 mycotoxin in young adult mice was 0.08 +/- 0.04 mg T-2/liter air and that for mature mice was 0.325 +/- 0.1 mg T-2/liter air. Deaths among mice exposed to the higher aerosol concentrations used in this study (i.e., 1.5 to 2.4 mg T-2/liter air) occurred in less than 5 hr. General clinical symptoms in these animals immediately postexposure were tremors, lethargy, stilted gait, and, in some animals, prostration. In experiments separate from the concentration-response studies, total deposition of T-2 aerosol and selective retention of T-2 in the respiratory tract and nasal turbinates were determined analytically from 3H-labeled T-2. When total deposition of T-2 was quantitated, there was excellent agreement between that amount of T-2 deposited and that amount of T-2 predicted from calculations based on aerosol size and animal minute volume. Based on the aerosol deposition data, the LD50 values of T-2 mycotoxins was 0.24 mg/kg for young adult mice and 0.94 mg/kg for mature mice. For mice, inhalation of T-2 mycotoxin is at least 10 times more toxic than systemic administration (LD50 approximately 4.5 mg/kg) and at least 20 times more toxic than dermal administration (LD50 greater than 10 mg/kg).

Aerosols↗

PubMed1979

Nuclear interaction of Fusarium mycotoxins with estradiol binding sites in the mouse uterus.

By using cell-free preparations of uteri obtained from immature BALB/c mice, it was demonstrated that zearalenone and zearalanol, Fusarium mycotoxins, inhibited [3H]estradiol-17 beta binding to specific sites in cytosol. Significant inhibition was noted from zearalenone at 4 x 10(-6) M and from zearalanol at 4 x 10(-7) M. Unlabeled mycotoxins (5 x 10(-6) M) incubated with intact uteri caused translocation of specific estrogen binding sites into nuclei that were exchangeable with [3H]estradiol-17 beta. Zearalanol was more effective in this regard than zearalenone. Ability of the mycotoxins to compete with estradiol-17 beta for the cytosol receptor and to cause translocation of the receptor to the nucleus in general is correlated with their biological activity. These data suggest that the uterotrophic effects of Fusarium mycotoxins are mediated through their association with estrogen receptors in the uterus.

Animals↗

PubMed2007

Reduced contamination by the Fusarium mycotoxin zearalenone in maize kernels through genetic modification with a detoxification gene.

Maize is subject to ear rot caused by toxigenic Aspergillus and Fusarium species, resulting in contamination with aflatoxins, fumonisins, trichothecenes, and zearalenone (ZEN). The trichothecene group and ZEN mycotoxins are produced by the cereal pathogen Fusarium graminearum. A transgenic detoxification system for the elimination of ZEN was previously developed using an egfp::zhd101 gene (gfzhd101), encoding an enhanced green fluorescent protein fused to a ZEN-degrading enzyme. In this study, we produced a transgenic maize line expressing an intact copy of gfzhd101 and examined the feasibility of transgene-mediated detoxification in the kernels. ZEN-degrading activity has been detected in transgenic kernels during seed maturation (for a period of 6 weeks after pollination). The level of detoxification activity was unaltered after an additional storage period of 16 weeks at 6 degrees C. When the seeds were artificially contaminated by immersion in a ZEN solution for 48 h at 28 degrees C, the total amount of the mycotoxin in the transgenic seeds was uniformly reduced to less than 1/10 of that in the wild type. The ZEN in the transgenic maize kernels was also efficiently decontaminated under conditions of lower water activity (aw) and temperature; e.g., 16.9 microg of ZEN was removed per gram of seed within 48 h at an aw of 0.90 at 20 degrees C. F. graminearum infection assays demonstrated an absence of ZEN in the transgenic maize seeds, while the mycotoxin accumulated in wild-type kernels under the same conditions. Transgene-mediated detoxification may offer simple solutions to the problems of mycotoxin contamination in maize.

Biotechnology↗

PubMed1997

Mycotoxin production by fusarium species isolated from bananas.

The ability of Fusarium species isolated from bananas to produce mycotoxins was studied with 66 isolates of the following species: F. semitectum var. majus (8 isolates), F. camptoceras (3 isolates), a Fusarium sp. (3 isolates), F. moniliforme (16 isolates), F. proliferatum (9 isolates), F. subglutinans (3 isolates), F. solani (3 isolates), F. oxysporum (5 isolates), F. graminearum (7 isolates), F. dimerum (3 isolates), F. acuminatum (3 isolates), and F. equiseti (3 isolates). All isolates were cultured on autoclaved corn grains. Their toxicity to Artemia salina L. larvae was examined. Some of the toxic effects observed arose from the production of known mycotoxins that were determined by thin-layer chromatography, gas chromatography, or high-performance liquid chromatography. All F. camptoceras and Fusarium sp. isolates proved toxic to A. salina larvae; however, no specific toxic metabolites could be identified. This was also the case with eight isolates of F. moniliforme and three of F. proliferatum. The following mycotoxins were encountered in the corn culture extracts: fumonisin B(inf1) (40 to 2,900 (mu)g/g), fumonisin B(inf2) (150 to 320 (mu)g/g), moniliformin (10 to 1,670 (mu)g/g), zearalenone (5 to 470 (mu)g/g), (alpha)-zearalenol (5 to 10 (mu)g/g), deoxynivalenol (8 to 35 (mu)g/g), 3-acetyldeoxynivalenol (5 to 10 (mu)g/g), neosolaniol (50 to 180 (mu)g/g), and T-2 tetraol (5 to 15 (mu)g/g). Based on the results, additional compounds produced by the fungal isolates may play prominent roles in the toxic effects on larvae observed. This is the first reported study on the mycotoxin-producing abilities of Fusarium species that contaminate bananas.

Journal Article↗

PubMed1991

Immunoassay of ochratoxin and other mycotoxins from a single extract of cereal grains utilizing monoclonal antibodies.

Immunoassays provide rapid, specific, sensitive and inexpensive methods for analysing mycotoxins but have generally been tested individually. Mycotoxigenic fungi rarely occur in pure culture in nature, and different mycotoxins may occur together. It would therefore be advantageous if several immunoassays for different mycotoxins could utilize a single extract. Monoclonal antibodies specific for ochratoxin A, aflatoxin B1 and T-2 toxin, raised at the University of Strathclyde, allow detection limits of 1 ng/ml ochratoxin A, 0.1 ng/ml aflatoxin B1 and 10 ng/ml T-2 toxin, when used in competitive enzyme-linked immunosorbent assays. These antibodies have been used to assay ochratoxin A. aflatoxin B1 and T-2 toxin in a single acetonitrile: 0.5% KCl:6% H2SO4 (89:10:1) extract of cereal grain. Extracts were either diluted 1:10 for direct assay or subjected, before assay, to a simple liquid-liquid clean-up procedure, which removed interfering substances and resulted in a 5:1 concentration. Recoveries from barley to which mycotoxins had been added averaged 95.8% for ochratoxin A, 93.8% for aflatoxin B1 and 80.6% for T-2 toxin, and the detection limits were 5 ng/g for ochratoxin A, 4 ng/g for aflatoxin B1 and 50 ng/g for T-2 toxin. Mean coefficients of variation within and between assays and between subsamples were less than 12% for ochratoxin A and aflatoxin B1 but up to 17% for T-2 toxin in assays of barley inoculated with toxigenic fungi.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetonitriles↗

PubMed1991

[Mycotoxins as a risk factor for the origin of diseases and production decreases in swine facilities--an epidemiologic study].

Feed samples checked for the mycotoxins zearalenone and ochratoxin A from the harvest 1987 were positive at a markedly higher percentage (37.5%) compared to previous years, which is explained by the especially unfavourable harvesting conditions of 1987. In certain herd problems affecting the digestive or respiratory tract, mycotoxins could be detected with a much higher frequency (64.7% and 50.0% respectively). The mean level detected in feed samples by thin layer chromatography ranged within 30.3 ppb for zearalenone and within 58.3 ppb for ochratoxin A. In most cases there was a history of infertility. Considering the clinical situation, which is presented comparatively in herds with positive mycotoxin results, the possible involvement of mycotoxins in the disease, even at very low concentrations, is pointed out. In this context, zearalenone is incriminated of being an indicator of a multitoxic process besides its own direct effects. According to own experiences low levels of zearalenone in the range of 20-50 ppb in the feed have to be considered hazardous. If changing of pig feed in cases of herd problems will be recommended, a level of less than 10 ppb of zearalenone, especially in sow and piglet rations, should not be exceeded. Same may be valid to ochratoxin A.

Animal Feed↗

PubMedDate not supplied

Embryotoxicity and mutagenicity of mycotoxins.

Embryotoxicity: Aflatoxin B1 (AFB1), G1 (AFG1), and Patulin (PA) were investigated in NMRI mice for embryotoxic and teratogenic activity. These three mycotoxins were injected intraperitoneally or given orally on day 12 and 13 of pregnancy. AFB1 (15, 45, and 90 mg/kg ip or 45 mg/kg po) produced moderate retardation in fetal development and a dose-related increase of cleft palates, wavy ribs, and diaphragm changes. The effects after injection of AFG1 (45 to 90 mg/kg ip) were reduction of fetal weights, increase of diaphragm changes, and malformations of kidneys. PA (1, 25, 2, 5, and 3.75 mg/kg ip or 3.75 mg/kg po) was found to elevate the rate of cleft palates after 3.75 mg/kg. Dominant lethal assay: Neither PA (2, 5, and 5 mg/kg ip) nor AFB1 (15 and 45 mg/kg ip) increased the frequency of the dominant lethal mutations. Both mycotoxins showed no mutagenic activity in this test system. Cytogenetic studies: The capability of the three mycotoxins AFB1, AFG1, and PA to induce chromosome damages in vivo has been tested in the Chinese hamster by examination of bone marrow cells. The substances were tested in each of two oral doses (AFB1: 12, 5, and 25 mg/kg; 25 and 50 mg/kg; PA: 10 and 20 mg/kg). The present data show that the three mycotoxins induce chromosome aberrations in the following order of activity: PA greater than AFB1 greater than AFG1.

Abnormalities, Drug-Induced↗

PubMed1999

Effect of Aspergillus terreus mycotoxins on nitric oxide synthase activity in human erythroid K-562 cells.

Because several stimuli of microbial origin enhance the activity of nitric oxide synthase (NOS) in human cells of the myeloid lineage, we decided to investigate whether cellular damage induced by Aspergillus terreus mycotoxins could be associated with an increase in NOS activity. A pool of mycotoxins rather than individual toxins was tested so that the natural conditions could be mimicked. In the present study, we report that a crude extract of A. terreus induces cellular damage and increases NOS activity in K-562 cells, an erythroleukaemic cell line in which NOS is particularly active. The specificity of this association was further investigated by using NOS inhibitors and by comparing, in the same cellular model, the effects of the extract with the activity of other microbial toxins of a defined mechanism of action. Canavanine, an inhibitor of NOS, significantly reduced cell death in the presence of the extract, suggesting that cellular damage, induced by the mycotoxins of A. terreus is at least in part mediated by NOS activity. Moreover, Escherichia coli lipopolysaccharide (LPS), known to be a potent NOS inducer, increased NOS activity in our experimental model as well. In contrast, Bordetella pertussis toxin did not show any effect on NOS activity. The results of this study suggest that NOS may be involved in mycotoxicoses.

Aspergillosis↗