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PubMed2002

Fungal growth and fusarium mycotoxin content in isogenic traditional maize and genetically modified maize grown in France and Spain.

Fungi of the genus Fusarium are common fungal contaminants of maize and are also known to produce mycotoxins. Maize that has been genetically modified to express a Bt endotoxin has been used to study the effect of insect resistance on fungal infection of maize grains by Fusarium species and their related mycotoxins. Maize grain from Bt hybrids and near-isogenic traditional hybrids was collected in France and Spain from the 1999 crop, which was grown under natural conditions. According to the ergosterol level, the fungal biomass formed on Bt maize grain was 4-18 times lower than that on isogenic maize. Fumonisin B(1) grain concentrations ranged from 0.05 to 0.3 ppm for Bt maize and from 0.4 to 9 ppm for isogenic maize. Moderate to low concentrations of trichothecenes and zearalenone were measured on transgenic as well as on non-transgenic maize. Nevertheless, significant differences were obtained in certain regions. The protection of maize plants against insect damage (European corn borer and pink stem borer) through the use of Bt technology seems to be a way to reduce the contamination of maize by Fusarium species and the resultant fumonisins in maize grain grown in France and Spain.

Bacillus thuringiensis↗

PubMed2005

Masked mycotoxins: determination of a deoxynivalenol glucoside in artificially and naturally contaminated wheat by liquid chromatography-tandem mass spectrometry.

Conjugated mycotoxins, in which the toxin is usually bound to a more polar substance like glucose, are referred to as masked mycotoxins, as these substances escape routine detection methods but can release their toxic precursors after hydrolysis. This is the first report on the natural occurrence of a glucoside of deoxynivalenol (DON) in Fusarium-infected wheat and maize. To obtain appropriate standards, we chemically synthesized deoxynivalenol-3-beta-D-glucopyranoside (DON-3-glucoside) and deoxynivalenol-15-beta-D-glucopyranoside (DON-15-glucoside). The synthesis products were characterized by liquid chromatography-tandem mass spectrometry. The DON-glucosides showed different collision-induced dissociation (CID) fragmentation behaviors and could therefore be distinguished. Wheat plants were either treated with DON (n = 52) or with Fusarium spp. (n = 4) at anthesis, and after harvest, wheat ears were analyzed for DON and DON-glucosides. All 56 treated wheat samples contained DON and a DON-glucoside with the same retention time, molecular mass, and CID fragmentation behavior as the synthetic DON-3-glucoside. Moreover, the DON-glucoside was also found in two out of three analyzed naturally DON-contaminated maize and in five out of five naturally contaminated wheat samples, in a range from 4 to 12% of the DON concentration. To further confirm the identity of the DON-glucoside, the compound was isolated from wheat extracts and characterized as DON-3-glucoside with NMR. The results of this study indicate the importance to consider both DON and DON-3-glucoside with regard to food and feed safety.

Chromatography, Liquid↗

PubMed1999

Production of the mycotoxins fusaproliferin and beauvericin by South African isolates in the Fusarium section Liseola.

The production of fusaproliferin (FUS), a recently described mycotoxin, and beauvericin (BEA), a mycotoxin recently reported to co-occur with FUS in Fusarium-infected corn, by South African isolates in the Fusarium section Liseola, was investigated. Five isolates each of F. verticillioides, F. proliferatum, F. subglutinans, and F. globosum were cultured on corn kernels. Four each of the five South African isolates of F. proliferatum and F. subglutinans produced FUS (10-1725 and 330-2630 mg/kg, respectively). BEA was produced by four of the F. proliferatum strains (310-1130 mg/kg) and three of the F. subglutinans strains (140-700 mg/kg). The isolates of F. verticillioides failed to produce significant levels of either of these secondary metabolites. F. globosum was a weak producer of both in that one isolate of five produced 25 mg/kg FUS and five out of five produced BEA at levels ranging between 10 and 110 mg/kg. To further characterize these strains, their production of fumonisins B(1), B(2), and B(3), as well as moniliformin, was investigated. Of the four species investigated, fumonisins were produced by all except F. subglutinans, which in turn was the only species whose isolates in this study produced moniliformin (four of five isolates, ranging from 155 to 2095 mg/kg). Analysis of visibly Fusarium-infected home-grown corn collected in the Transkei region of the Eastern Cape Province of South Africa showed that nine of the ten samples contained low levels of FUS (up to 62 microg/kg), whereas all ten samples showed BEA contamination ranging from 8 to 1734 microg/kg with a mean of 258 microg/kg.

Anti-Bacterial Agents↗

PubMed1998

Mycoflora and naturally occurring mycotoxins in poultry feeds in Argentina.

The purpose of this work was to determine the mycoflora and mycotoxins natural incidence in poultry feeds from 2 factories in Río Cuarto, Córdoba. One hundred and thirty samples were taken from May/1996 to May/1997. The most dominant species isolated of poultry feed samples belonged to the genera Aspergillus spp 85% and Fusarium spp 70%. From Aspergillus genus eleven species were identified and A. flavus was the most frequent. Nine species were identified from the Fusarium genus and the predominant was F. moniliforme. Penicillium ranked third in the number of isolated cases. From this genus twelve species were collected of which P. brevicompactum (15%), P. restrictum (14%) and P. purpurogenum (12%) were the most common. The most significant mycotoxin from poultry feeds was aflatoxin B1 (AFB1) found in 48% of the samples, with levels ranging from 10 to 123 ng/g. For zearalenone (ZEA) the levels were 327 to 5, 850 ng/g and DON was not detected from the samples. Due to the fact that in Argentina there is little information about this topic, these data on poultry feeds in our region would be of worldwide interest.

Aflatoxin B1↗

PubMed1999

Prevalence of Fusarium species of the Liseola section on Zimbabwean corn and their ability to produce the mycotoxins zearalenone, moniliformin and fumonisin B1.

Maize samples were collected from nine Grain Marketing Board (G.M.B) centers in Zimbabwe during the 1991 harvest season. A further 47 samples collected directly from farmers and from the G.M.B., centers in Chinhoyi and Kwekwe during the 1992 harvest season. These samples were analyzed mycologically and the predominant flora was Fusarium although Penicillium, Nigrospora, Aspergillus and Chaetomium could be isolated from some samples. From the first nine samples studied, F. verticillioides and F. subglutinans were isolated in almost equal proportions on samples from the central and the south of the country whereas only F. verticillioides was isolated on the samples from the north. The subsequent study demonstrated that there was a greater fungal diversity in samples from North (Mashonaland West) than samples from the South (Midlands area) with species of Nigrospora, Chaetomium, Acremonium and Diplodia occurring in significant numbers. From a total of 2821 fungal isolates obtained from all the maize samples analyzed, 1485 (53%) were found to belong to the liseola section of Fusarium. The ability of these isolates to produce the mycotoxins zearalenone, moniliformin and fumonisin B1 was tested using a simplified TLC Agar plate method. Out of the 886 isolates tested, only one produced all the three mycotoxins simultaneously whilst most produced fumonisin B1 and/or moniliformin. Only nine isolates produced zearalenone.

Carboxylic Acids↗

PubMed2002

Comparison of Canadian Fusarium graminearum isolates for aggressiveness, vegetative compatibility, and production of ergosterol and mycotoxins.

Fusarium graminearum is the predominant pathogen causing fusarium head blight of cereals in North America. Fifteen Canadian isolates of Fusarium graminearum were highly diverse in terms of vegetative compatibility grouping (VCG) and varied for production of ergosterol and mycotoxin production in rice culture. Aggressiveness was assessed by scoring the disease severity incited in wheat spikes by each isolate. Two inoculation methods, single-floret injection and spray of entire spikes, were used to screen 4 wheat varieties for reaction to the F. graminearum isolates. All isolates were of broadly similar aggressiveness, with disease severity ranging from 17.2 to 39.1 for single floret injection, and 39.1 to 69.0 for spray inoculation. Disease severity, ergosterol production, and mycotoxin development were not correlated. Using nitrate non-utilizing mutants the 15 isolates were grouped into 14 VCGs. Deoxynivalenol (DON) was produced by all isolates in rice culture, at levels between 0.2 and 249 ppm. 15-acetyldeoxynivalenol was produced by 14 of the 15 isolates at levels between 0.4 and 44.6 ppm. These results reveal a high level of diversity for several characteristics among F. graminearum isolates from Canada.

Culture Media↗

PubMed2003

Mycotoxin production and evolutionary relationships among species of Aspergillus section Clavati.

Aspergillus clavatus is a commonly encountered fungus in the environment, producing a number of mycotoxins including patulin, kojic acid, cytochalasins and tremorgenic mycotoxins. A. clavatus belongs to Aspergillus section Clavati together with six other species, all of which possess clavate-shaped vesicles. Patulin production was analysed by thin layer chromatography and high performance liquid chromatography, while a primer pair developed for the detection of an iso-epoxydon dehydrogenase gene involved in the biosynthesis of patulin in penicillia was used to detect the ability of patulin production in the isolates examined. A good correlation was observed between patulin producing properties, and the presence of an iso-epoxydon dehydrogenase gene fragment among the isolates tested. A. longivesica was found for the first time to produce patulin. Ribotoxin production was also examined using a PCR-based approach. Ribotoxins were detected for the first time in an A. pallidus and a Hemicarpenteles acanthosporus isolate. A phylogenetic analysis of intergenic transcribed spacer sequence data indicated that most isolates belong to two main clades that have also been identified earlier based on 26 S rDNA sequence data. A. pallidus isolates clustered together with A. clavatus strains. Although A. clavatus isolates produced highly homogeneous random amplified polymorphic DNA profiles, phylogenetic analysis of these data let us cluster A. clavatus isolates into distinct clades. Correlations were not observed between either patulin or ribotoxin production, and the taxonomic position of the isolates tested, indicating that patulin and ribotoxin producing abilities were lost several times during evolution of Aspergillus section Clavati. Although patulin was earlier found to inhibit mycovirus replication, one of the mycovirus carrying isolates also produced patulin, and both carried the iso-epoxydon dehydrogenase gene.

Aspergillus↗

PubMed2004

Analysis of Fusarium graminearum mycotoxins in different biological matrices by LC/MS.

The purpose of this study was to develop an LC/MS assay to accurately detect three mycotoxins produced by Fusarium graminearum in various matrices. Using different LC conditions, deoxynivalenol (DON), 15-acetyldeoxynivalenol (15-ADON), and zearalenone (ZEN) were detected in four different matrices (fungal liquid cultures, maize grain, insect larvae and pig serum). The sensitivity of MS detection allowed us to detect concentrations as low as 8 ppb of DON and 12 ppb of ZEN. A very small quantity of matrix was therefore necessary for successful analysis of these toxins and a variety of experimental situations were successfully investigated using this technique. Production of 15-ADON and butenolide was monitored in a liquid culture of F. graminearum under controlled conditions. Using simple extraction procedures, the differential accumulation of DON and 15-ADON was followed in inoculated maize genotypes varying in susceptibility to F. graminearum. Toxicokinetic studies were carried out with maize insect pests reared continually on artificial diets containing ZEN and suggested that larvae may possess the ability to degrade ZEN. Finally, persistence of DON was assessed in pigs fed diet supplemented with DON, results indicated that DON accumulates quickly in pig blood and then levels decline progressively for 12 hours thereafter. The LC/MS study reported here is very useful and flexible for the detection of these mycotoxins in different media and at very low concentrations.

Animals↗

PubMed2004

Mycotic keratitis: profile of Fusarium species and their mycotoxins.

In this study, Fusarium species isolated from 29 patients with mycotic keratitis were identified and tested for their ability to produce mycotoxins. Members of the F. solani species complex (Fs complex) were the predominant species isolated, followed by F. verticillioides, F. dimerum, members of the F. oxysporum species complex Fo complex), F. incarnatum, F. chlamydosporum and F. lateritium. Of these, 76% of the Fusarium isolates produced fusaric acid, moniliformin or fumonisin B1. Many of the fusaria isolated are common aetiological agents of mycotic keratitis infections. However, F. incarnatum, F. chlamydosporum and F. lateritium have previously not been found in this infection. These findings indicate that a greater variety of fusarial species are becoming associated with mycotic keratitis infections. This paper further demonstrates the mycotoxin-producing ability of these clinical isolates and assesses cellular cytotoxicity.

Animals↗

PubMed2003

Detoxification of the Fusarium mycotoxin deoxynivalenol by a UDP-glucosyltransferase from Arabidopsis thaliana.

Plant pathogenic fungi of the genus Fusarium cause agriculturally important diseases of small grain cereals and maize. Trichothecenes are a class of mycotoxins produced by different Fusarium species that inhibit eukaryotic protein biosynthesis and presumably interfere with the expression of genes induced during the defense response of the plants. One of its members, deoxynivalenol, most likely acts as a virulence factor during fungal pathogenesis and frequently accumulates in grain to levels posing a threat to human and animal health. We report the isolation and characterization of a gene from Arabidopsis thaliana encoding a UDP-glycosyltransferase that is able to detoxify deoxynivalenol. The enzyme, previously assigned the identifier UGT73C5, catalyzes the transfer of glucose from UDP-glucose to the hydroxyl group at carbon 3 of deoxynivalenol. Using a wheat germ extract-coupled transcription/translation system we have shown that this enzymatic reaction inactivates the mycotoxin. This deoxynivalenol-glucosyltransferase (DOGT1) was also found to detoxify the acetylated derivative 15-acetyl-deoxynivalenol, whereas no protective activity was observed against the structurally similar nivalenol. Expression of the glucosyltransferase is developmentally regulated and induced by deoxynivalenol as well as salicylic acid, ethylene, and jasmonic acid. Constitutive overexpression in Arabidopsis leads to enhanced tolerance against deoxynivalenol.

Amino Acid Sequence↗

PubMed2004

Trichosporon mycotoxinivorans sp. nov., a new yeast species useful in biological detoxification of various mycotoxins.

A yeast strain isolated from the hindgut of the lower termite Mastotermes darwiniensis (Mastotermitidae) was found to represent a new member of the genus Trichosporon. Trichosporon mycotoxinivorans is closely related to T. loubieri on the basis of the phylogenetic trees based on the D1/D2 region of 26S rDNA, an approx. 600 bp fragment of the 18S rDNA and both ITS regions. However, the two species differ at nine positions in the D1/D2 region of 26S rDNA. The IGS1 region of T. mycotoxinivorans is 401 bp long. T. mycotoxinivorans is distinguished from T. loubieri by its ability to assimilate inulin and galactitol, and its inability to grow at 40 degrees C. The name of this newly isolated strain refers to an important characteristics of T. mycotoxinivorans to detoxify mycotoxins such as ochratoxin A and zearalenone. Therefore this strain can be used for the deactivation of the respective mycotoxins in animal feeds.

Animals↗

PubMed2000

Species-specific profiles of mycotoxins produced in cultures and associated with conidia of airborne fungi derived from biowaste.

The potential to produce mycotoxins and non-volatile secondary metabolites was investigated for approximately 250 freshly isolated fungal strains. Among the eleven most relevant species, viz. Aspergillus flavus, A. fumigatus, A. niger, A. parasiticus, A. versicolor, Emericella nidulans, Paecilomyces variotii, Penicillium brevicompactum, P. clavigerum, P. crustosum, and P. polonicum, a wide range of metabolites partly of toxicological relevance was identified. Several unknown metabolites were found for the less frequent species, which were primarily investigated for chemotaxonomic delimitation from closely related species. The spectra of metabolites in conidial extracts and culture extracts (containing also mycelium and medium) were compared for a limited number of relevant fungi. Some mycotoxins, such as sterigmatocystin in Emericella nidulans, were not present in the conidial extracts, though produced by most strains. Fumigaclavine C, tryptoquivaline, and trypacidin, characteristic for A. fumigatus, were found in conidial extracts, but highly toxic compounds such as gliotoxin and fumitremorgens were not present. Finally, compounds such as cyclopenol, cyclopenin, and penitrem A being characteristic for certain penicillia, were found in conidial extracts and are therefore assumed to occur in native bioaerosols.

Air Microbiology↗

PubMed2004

In vitro studies on the evaluation of mycotoxin detoxifying agents for their efficacy on deoxynivalenol and zearalenone.

A simple in vitro system was developed to study the efficacy of commercially available mycotoxin detoxifying agents and adsorbing substances as feed additives to detoxify deoxynivalenol (DON) and zearalenone (ZON) in situ. The in vitro model simulates the conditions (pH, temperature and transit time) of the porcine gastrointestinal tract, as pigs react most sensitively to these mycotoxins. The commercially available products were not effective in detoxifying DON and ZON under the applied conditions, while activated carbon was able to bind both toxins and cholestyramine, and a modified aluminosilicate showed good adsorption abilities for ZON. Data obtained in dose dependency studies showed an estimated adsorption capacity of cholestyramine and the modified aluminosilicate of 11.7 and 5.7 g ZON/kg detoxifying agent. The in vitro system deployed in the present study was demonstrated to be a simple, helpful tool in screening substances for their ability to detoxify DON and ZON under the simulated conditions of the porcine gastrointestinal tract. Nonetheless in vivo experiments are indispensable to proof the efficacy.

Adsorption↗

PubMed1975

Mycotoxin-producing fungi from house associated with leukemia.

Fungi were isolated from a house associated with four leukemic patients from three families because of the possibility that mycotoxin-producing strains might be present. Extracts of several of the isolated fungal species produced toxic effects in one or more species of animals. Aflatoxin-producing Aspergillus parasiticus was isolated from non-leukemia-associated houses with the exception of Trichoderma, Verticillium, and Monotospora. We believe that certain mycotoxins may be related to pathogenesis of leukemia, possibly as an expression of their immunosuppressive effects.

Adult↗

PubMed2003

Use of functional brain imaging in the evaluation of exposure to mycotoxins and toxins encountered in Desert Storm/Desert Shield.

In this retrospective analysis the authors compared brain scintigrams, performed using triple-head single-photon emission computed tomography (tripleSPECT), of subjects who were judged clinically impaired from exposure to toxins during the Desert Storm/Desert Shield military action, and of subjects exposed to mycotoxins, with those of normal controls. The scintigrams for both exposed groups exhibited similar patterns of abnormalities, which were consistent with neurotoxic impairment. The authors conclude that further study is needed to determine whether mycotoxin exposure may be a cause of abnormalities seen in tripleSPECT images.

Adult↗

PubMed2001

Effect of the mycotoxin aurofusarin on the antioxidant composition and fatty acid profile of quail eggs.

1. The effect of the mycotoxin aurofusarin on the antioxidant composition and fatty acid profile of quail eggs was investigated. 2. Thirty eight 45-d-old Japanese quails were divided into two groups (experimental and control, 15 females +4 males in each group) and were fed on a maize-soya diet balanced in all nutrients. The diet of the experimental quails was supplemented with aurofusarin at the level of 26.4 mg/kg feed in the form of Fusarium graminearum culture enriched with aurofusarin. At the beginning and after 2, 4 and 8 week supplementation periods, eggs were collected and analysed. After 8 weeks of supplementation, experimental quails were fed on unsupplemented diet during the next 4 weeks and eggs were collected after 2 and 4 weeks on such a diet and analysed. 3. Aurofusarin caused a significant (P<0.05) decrease in vitamins E, A, total carotenoid, lutein and zeaxanthin concentrations and significantly (P<0.05) increased egg yolk susceptibility to lipid peroxidation. During two weeks on the diet without aurofusarin the levels of carotenoids in the egg yolk returned to the initial level, vitamins A and E returned to the initial level during 4 weeks on the same unsupplemented diet. 4. Dietary supplementation with aurofusarin was associated with a significant (P<0.01) decrease in the docosahexaenoic acid proportion in the phospholipid, cholesteryl ester and free fatty acid fractions of the egg yolk. At the same time the proportion of linoleic acid in the phospholipid, free fatty acid and triacylglycerol fractions significantly (P<0.05) increased. 5. It is concluded that mycotoxin aurofusarin is detrimental to the nutritional quality of eggs.

Animals↗

PubMed1996

Effects of mycotoxins on cytokine production and proliferation in EL-4 thymoma cells.

The thymoma cell line EL4.IL-2 (EL-4) was used as a T-cell model to assess the immunotoxic effects of several mycotoxins produced by the Aspergillus-Penicillium and the Fusarium groups. EL-4 cells were stimulated with phorbol 12-myristate 12-acetate (PMA) in the presence of mycotoxins at various concentrations for 5 d and culture supernatants were analyzed for interleukins (IL) IL-2 and IL-5 by enzyme-linked immunosorbent assay (ELISA). The cytokine effects were further related to proliferation and cell viability using the MTT [3-(4,5-dimethylthiazol-2-yl) 2,5-diphenyltetrazolium bromide] assay with absorbance at 570 nm (A570) as the endpoint indicator. IL-2 and IL-5 levels were dramatically increased by cyclopiazonic acid at 50-1000 ng/ml, whereas IL-2 was significantly decreased at 10 microgram/ml. Proliferation was slightly increased at 100-1000 ng/ml cyclopiazonic acid but markedly depressed at 5 and 10 microgram/ml. When EL-4 cells were exposed to 5 and 10 microgram/ml of ochratoxin A, IL-2 production was markedly increased while IL-5 production was significantly decreased. The A570 was significantly decreased by ochratoxin A at 10 microgram/ml. IL-2 and Il-5 production was almost totally suppressed by patulin at concentrations > or = 500 ng/ml and by T-2 toxin at > or = 5 ng/ml. These effects occurred concurrently with marked depression of A570 in the MTT assay. Although A570 was unaffected by either zearalenone or alpha-zearalenol exposure, both IL-2 and IL-5 levels were significantly elevated by these toxins at 5 or 10 microgram/ml. IL-2 and IL-5 production were not affected in EL-4 cells cultured with either the Aspergillus-Penicillium toxins aflatoxin B1 and secalonic acid or the Fusarium toxins wortmannin, fumonisin B1, or fusaric acid at concentrations up to 10 microgram/ml. In total, the EL-4 culture studies indicated that cyclopiazonic acid, ochratoxin A, zearalenone, and alpha-zearalenol could stimulate cytokine production whereas patulin and T-2 toxin were inhibitory. Cytokine dysregulation was not always related directly to perturbations in proliferation. The results suggest that the EL-4 thymoma cell line could be a simple and effective in vitro model for evaluating immunotoxicity of various classes of environmental chemicals.

Androstadienes↗

PubMed1981

Fusarium mycotoxins and the effects of high-fat diets.

Some of the inconsistencies encountered in epidemiological and experimental studies on the role of various types of fats in the etiology of cardiovascular disorders and certain tumors (of the breast, endometrium, and colon, among others) may be related to the presence of adventitious contaminants in the fats. Among the contaminants, mycotoxins, especially those produced in agricultural products by the Fusarium field-microfungi (the irritant trichothecenes, the estrogenic zearalenone, and other resorcylic acid lactones), warrant particular attention. Their production is favored by the wet, cool weather prevailing in areas notable for high incidences of the aforementioned disorders. The recent development of sensitive radioimmunoassays for the detection and estimation of some of these mycotoxins should facilitate the testing of the above hypothesis.

Animals↗