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At least 1,027 records · Page 57Linked to original sources
PubMed1988

[The occurrence of Fusarium varieties and their mycotoxins in silo corn. 2. The formation of zearalenone in the field by artificial infection of silo corn with Fusarium culmorum (W. G. Smith) Sacc].

The formation of zearalenone in a maize plot artificially infected with Fusarium culmorum was studied. The zearalenone concentration steeply increased only in the 8th week after inoculation and reached a maximum value of ca. 7 ppm, whereas zearalenone could not be detected in the control variants. The crude nutrient and dry matter content was not significantly influenced by the fungal infection. The infected crop showed average ear dry weights distinctly lower than that of the control variants (P less than or equal to 0.001). Apart from zearalenone, the mycotoxin deoxynivalenol was qualitatively detected in the infected maize. The toxicological relevance of the ascertained zearalenone content with regard to the health of dairy cattle and pigs was discussed.

Animal Feed↗
PubMed1990

[Occurrence of Fusarium strains and their mycotoxins on corn silage. 6. Formation of zearalenone and trichothecenes (type A) by indigenous Fusarium isolates].

A total of 399 indigenous Fusarium strains mainly isolated from silage maize were tested for the production of zearalenone and type A trichothecenes by thin-layer chromatography and biological assays. About 45% of the isolates examined were capable of producing different levels of zearalenone and trichothecene toxins on a cracked corn substrate. The majority of these strains (75%) produced zearalenone only and no trichothecenes type A. The results of the biological tests indicated a higher rate of toxin-positive extracts than chemical analysis. Isolates of nine out of seventeen Fusarium species examined produced one or several mycotoxins looked for. The most important toxin producers were F. culmorum and F. crookwellense (zearalenone) and F. sporotrichioides (trichothecenes type A), respectively. F. avenaceum, the species most frequently isolated from silage maize, produced neither zearalenone nor trichothecenes but avenacein Y a antibiotic compound. First results of a study of the production of type B trichothecenes have shown that indigenous F. culmorum isolates were capable of producing high levels of deoxynivalenol.

Anti-Bacterial Agents↗
PubMed1990

[Occurrence of Fusarium strains and their mycotoxins in corn silage. 7. Formation of deoxynivalenol (DON) in a silage corn plot artificially inoculated with Fusarium culmorum and the effect of silaging on the stability of the DON formed].

The formation of deoxynivalenol in a maize plot inoculated with Fusarium culmorum was studied over a growing season. Already three weeks after inoculation 4.9 mg/kg of DON were measured in the infected ears. The toxin concentration increased continuously up to harvest after eight weeks to a value of 261 mg/kg. Ensilage experiments in laboratory scale silos have shown that the DON content of naturally contaminated corn-cob-mix was not reduced during the ensilage process. It was concluded that infection of maize plants by toxin-producing Fusarium species followed by DON production in the field seems to be the most probable way of contamination of maize silage with this mycotoxin.

Animals↗
PubMed2003

Efficient adsorption of the mycotoxins zearalenone and T-2 toxin on a modified yeast glucan.

1,3-Beta-D-glucan derived from baker's yeast was chemically modified in two steps yielding crosslinked carboxymethyl glucan as the sodium salt (2). After cation exchange with hexadecyltrimethylammonium chloride, a hydrophobic adsorbent (3) was obtained which showed an excellent binding of the estrogenic mycotoxin zearalenone with a maximum adsorption of up to 183 mg/g. Compound 3 additionally showed a relatively high adsorption capacity for the trichothecene T-2 toxin of at least 10 mg/g. Starting from 2, various derivatives were prepared by cation exchange using quaternary ammonium salts bearing substituents besides methyl from four to 18 carbon atoms. The adsorption of T-2 toxin on these derivatives were compared with compound 3 leading to the conclusion that 3 is the best adsorbent of all investigated tetraalkylammonium-modified derivatives of 2.

Adsorption↗
PubMed1995

Genotoxicity of zearalenone, an estrogenic mycotoxin: DNA adduct formation in female mouse tissues.

Zearalenone is a non-steroidal estrogenic mycotoxin produced by several species of Fusarium which colonize maize, barley, oats, wheat and sorghum and have been implicated in numerous mycotoxicoses in farm animals, especially pigs. In a NTP mouse study a dose-related incidence of hepatocellular adenomas was seen in female mice. A limited number of genotoxicity assays have been conducted with zearalenone. Zearalenone was found to be negative in the Salmonella typhimurium assay. It was also negative in a eukaryotic cell mutation assay with Saccharomyces cerevisae. However, zearalenone and its estrogenic metabolites showed a positive DNA damaging effect in recombination tests with Bacillus subtilis. In this study DNA adducts in female mice and rat treated i.p or orally with zearalenone were determined using a 32P-postlabeling method. Several DNA adducts (12-15) were found in the kidney and liver of female mice treated with a single dose of zearalenone (2 mg/kg i.p. or orally). The total DNA adduct levels reached 114 +/- 37 and 1393 +/- 324 adducts/10(9) nucleotides respectively in kidney and liver after i.p. treatment and 548 +/- 50 adducts/10(9) nucleotides in liver after oral treatment. In mice ovary DNA adducts appeared only after repeated doses (1 mg/kg body wt on days 1, 5, 7, 9 and 10). The total DNA adducts after 10 days in this organ were 17 +/- 5 adducts/10(9) nucleotides. Some adducts were common to all organs. Others were specific to an organ. In contrast, no DNA adducts could be detected in rat organs after i.p. treatment. These results confirm the genotoxicity of zearalenone and its ability to induce hepatocellular adenomas, rather than tumours of genital organs, in mice.

Animals↗
PubMed1985

Rapid and high resolution capillary supercritical fluid chromatography (SFC) and SFC/MS of trichothecene mycotoxins.

The potential application of capillary column supercritical fluid chromatography (SFC) and SFC/mass spectrometry (SFC/MS) for the separation and analysis of mycotoxins of the trichothecene group was examined. Trichothecenes present significant analytical problems for both gas and liquid chromatography with a major difficulty for the latter being the lack of sufficiently sensitive and selective detectors. Supercritical carbon dioxide mobile phases at temperatures up to 100 degrees C were used with deactivated fused silica columns coated with crosslinked stationary phases. Separations were obtained under pressure ramped conditions using long (15 m) 50-micron i.d. columns for several trichothecenes (diacetoxyscirpenol, deoxynivalenol, and T-2 toxin) and related higher molecular weight macrocyclic (roridin and verrucarin) trichothecenes. In addition, new rapid pressure programming techniques with short (less than 2m) 25- to 50-micron i.d. capillary columns were used to obtain fast separations in as little as 1 min. SFC/MS with ammonia chemical ionization provided high selectivity and sensitive detection (with approximately 1-pg detection limits) for trichothecene mixtures. The extension to complex sample matrices is discussed and the application of selective MS/MS detection is demonstrated.

Chemical Phenomena↗
PubMed1977

Metabolism of trichothecene mycotoxins. I. Microsomal deacetylation of T-2 toxin in animal tissues.

In an attempt to elucidate the active form of T-2 toxin, one of trichothecene mycotoxins in vivo, the metabolism in animal tissues was studied in vitro by using gas liquid chromatography. T-2 toxin was selectively hydrolysed by the microsomal esterase at C-4, giving rise to HT-2 toxin as the only metabolite. This esterase activity was found mainly in the microsomes of liver, kidney, and spleen of laboratory animals. Since the enzymatic hydrolysis of T-2 toxin was inhibited by eserine, and diisopropylfluorophosphate, it is concluded that non-specific carboxyesterase [EC 3.1.1.1] of microsomal origin participates in this type of selective hydrolysis of T-2 toxin. The microsomal fraction from rabbit liver was proved to be a convinient material for the preparation of HT-2 toxin from T-2 toxin. From the evidence that the toxicity of HT-2 toxin is comparable to that of T-2 toxin and that the microsomal fraction of whole liver possesses the ability to biotransform the total lethal dose of T-2 toxin into HT-2 within a few minutes, T-2 toxin administered to animals is presumed to exhibit its toxicity partly as HT-2 toxin.

Animals↗
PubMed1978

Metabolism of trichothecene mycotoxins. II. Substrate specificity of microsomal deacetylation of trichothecenes.

The substrate specificity of microsomal nonspecific carboxyesterase [EC 3.1.1.1] from rabbit and rat livers was studied in vitro by using seven (A)-type and six (B)-type 12,13-epoxytrichothecene mycotoxins. The C-4 acetyl residues of diacetoxyscirpenol, T-2 toxin, monoacetylnivalenol (fusarenon-X), and diacetylnivalenol were selectively hydrolyzed by the microsomal esterase to yield the corresponding C-4-deacetylated metabolites: monoacetoxyscirpenol, HT-2 toxin, nivalenol, and 15-acetylnivalenol, respectively. The C-3 acetyl group of monoacetyldeoxynivalenol and the C-8 acetyl group of tetraacetoxyscirpen were also deacetylated. Triacetoxyscirpen gave rise to two unidentified metabolites, which may include a C-4-deacetylated product. 8-Hydroxydiacetoxyscirpenol (neosolaniol), HT-2 toxin, acetyl-T-2 toxin and tetraacetylnivalenol were unaffected by this type of hydrolysis. It follow from these results that the C-4 acetyl residue is hydrolyzed by the microsomal carboxyesterase and substituents at C-3 and C-8 contribute to the selective enzymatic hydrolysis of the C-4 acetyl residue of trichothecenes. Kinetic analysis showed that rabbit microsomal esterase possessed a high affinity for (A)-type trichothecenes such as T-2 toxin and diacetoxyscirpenol, and that of rat microsomes possessed a high affinity for (B)-type trichothecenes such as monoacetylnivalenol (fusarenon-X). The significance of this specific deacetylation reaction is discussed in relation to the biological activity of the trichothecene derivatives as revealed by their inhibitory effect on protein synthesis in rabbit reticulocytes.

Animals↗
PubMed2005

Mycotoxin fumonisin B1 alters the cytokine profile and decreases the vaccinal antibody titer in pigs.

Fumonisin B1 (FB1), a mycotoxin produced by Fusarium verticillioides, may contaminate feed and food. In the present study, we investigated the effect of FB1 on the modulation of the cytokine profile and on the establishment of a vaccinal antibody response. In vitro investigations on pig peripheral blood mononuclear cells (PBMC) indicate that FB1 decreased interleukin-4 (IL-4) and increased interferon-gamma (IFN-gamma) synthesis at both the protein and mRNA levels. A short in vivo exposure (7 days) of weanling piglets to 1.5 mg/kg body weight of purified FB1 altered the cytokine balance in mesenteric lymph nodes and spleen similarly to the in vitro PBMC results. We also investigated the effect of FB1 on the antibody response during a vaccination process. A prolonged in vivo exposure (28 days) of weanling piglets to feed contaminated with 8 mg FB1/kg significantly decreased the expression of IL-4 mRNA by porcine whole blood cells and diminished the specific antibody titer after vaccination against Mycoplasma agalactiae. By contrast, ingestion of the contaminated feed had no effect on the serum concentration of the immunoglobulin subset (IgG, IgA, and IgM). Taken together, our data suggest that FB1 alters the cytokine profile and decreases the specific antibody response built during a vaccination protocol. These results may have implications for humans or animals eating contaminated food or feed.

Animals↗
PubMed2005

Mycotoxin patulin activates the p38 kinase and JNK signaling pathways in human embryonic kidney cells.

Patulin (PAT), a mycotoxin mainly produced by Penicillium and Aspergillus, is frequently detected in moldy fruits and fruit products. Exposure of human embryonic kidney (HEK293) cells to PAT led to a dose- and time-dependent increase in the phosphorylation of two major mitogen-activated protein kinases (MAPKs), p38 kinase and c-Jun N-terminal kinase (JNK). The phosphorylated forms of MAPK kinase 4 (MKK4), c-Jun, and ATF-2 were also seen in PAT-treated cultures. The cell death caused by PAT was significantly reduced by the p38 kinase inhibitor, SB203580, but not by the JNK inhibitor, SP600125. Neither p38 kinase nor JNK played a role in the PAT-induced DNA damage. In PAT-treated cells, inactivation of double-stranded RNA-activated protein kinase R (PKR) by the inhibitor, adenine, markedly suppressed JNK and ERK phosphorylation. Treatment of HEK293 cells with PAT-cysteine adduct, a chemical derivative of PAT, showed no effect on MAPK signaling pathways, cell viability, or DNA integrity. These results indicate that PAT causes rapid activation of p38 kinase and JNK in HEK293 cells, but only the p38 kinase signaling pathway contributes to the PAT-induced cell death. PKR also plays a role in PAT-mediated MAPK activation.

Cell Line↗
PubMed2006

Induction of oxidative stress response by the mycotoxin patulin in mammalian cells.

Patulin (PAT), a mycotoxin mainly produced by Penicillium and Aspergillus, is found in various foods and feeds. In the present study, its effects on oxidative stress in various mammalian cell lines were investigated. When cell-permeating fluorescent dyes were used as indicators of the generation of reactive oxygen species (ROS), we found that PAT treatment directly increased intracellular oxidative stress in human embryonic kidney (HEK293) and human promyelocytic leukemia (HL-60) cells. Lipid peroxidation levels were also significantly increased in HL-60 cells and mouse kidney homogenates treated with PAT. Suppression of CuZn-superoxide dismutase (SOD) expression in mammalian cells by small interfering RNA resulted in an increase in PAT-mediated membrane damage, while overexpression of human CuZn-SOD or catalase led to a reduction in damage, indicating the involvement of ROS in PAT toxicity. Pretreatment of HEK293 cells with Tiron, a free radical scavenger, reduced the phosphorylation levels of extracellular signal-regulated kinase (ERK) 1/2 elicited by PAT. The ERK1/2 signaling pathway inhibitor, U0126, also significantly decreased the levels of ROS associated with PAT treatment. These findings indicate that PAT treatment results in the ROS production in mammalian cells, and ROS partially contributes to PAT-induced cytotoxicity. Activation of ERK1/2 signaling pathway is correlated with PAT-mediated ROS.

Animals↗
PubMed2005

Fundamental contribution of beta-oxidation to polyketide mycotoxin production in planta.

Seed contamination with polyketide mycotoxins, including aflatoxin (AF) and sterigmatocystin (ST) produced by Aspergillus spp., is an agricultural, economic, and medical issue worldwide. Acetyl-CoA, the fundamental building block of all known fungal polyketides, is generated by a large number of biochemical pathways, including beta-oxidation of fatty acids and glycolysis of sugars. We present several lines of evidence to support a major role for seed fatty acids in formation of AF and ST in A. flavus, A. parasiticus, and A. nidulans. Aspergillus strains exhibiting canonical signs of oleic acid-induced peroxisome proliferation, including increased catalase activity, beta-oxidation gene expression, and peroxisomal clustering, also exhibited a marked increase in toxin gene expression and biosynthesis. Furthermore, microscopic observations showed that the ST and AF precursor norsolorinic acid accumulated in peroxisomes of all three Aspergilli. While a peroxisomal beta-oxidation mutation eliminated oleic acid-induced increases in ST in A. nidulans, a mitochondrial beta-oxidation mutation played a larger role in eliminating ST formation on oatmeal medium and on live corn kernels, implicating a fundamental role for both peroxisomal and mitochondrial beta-oxidation in toxin production.

Aflatoxins↗
PubMed2002

Quantitative assessment of exposure to the mycotoxin Ochratoxin A in food.

This article presents the methodology and the simulation results concerning the quantitative assessment of exposure to the fungus toxin named Ochratoxin A (OA) in food, in humans in France. We show that is possible to provide reliable calculations of exposure to OA with the conjugate means of a nonparametric-type method of simulation, a parametric-type method of simulation, and the use of bootstrap confidence intervals. In the context of the Monte Carlo simulation, the nonparametric method takes into account the consumptions and the contaminations in the simulations only via the raw data whereas the parametric method depends on the random samplings from distribution functions fitted to consumption and contamination data. Our conclusions are based on eight types of food only. Nevertheless, they are meaningful due to the major importance of these foodstuffs in human nourishment in France. This methodology can be applied whatever the food contaminant (pesticides, other mycotoxins, Cadmium, etc.) when data are available.

Child↗
PubMed2005

The mycotoxins citrinin and gliotoxin differentially affect production of the pro-inflammatory cytokines tumour necrosis factor-alpha and interleukin-6, and the anti-inflammatory cytokine interleukin-10.

BACKGROUND: Microbial growth is considered one of the major causes of indoor air problems. Moulds have been associated with asthma, allergy and a wide range of diffuse indoor air-related symptoms. However, mechanisms of the adverse health effects are not well understood. OBJECTIVE: We hypothesized that the mycotoxins citrinin and gliotoxin could cause an imbalance between the secretion of the pro-inflammatory cytokines TNF-alpha and IL-6 and the anti-inflammatory cytokine IL-10. METHODS: We investigated the influence of citrinin and gliotoxin on the human monocytic cell line Mono-Mac-6 (MM6) with and without lipopolysaccharide -stimulation. The levels of IL-10, IL-6 and TNF-alpha were analysed in cell culture supernatants by ELISA. Cell viability and cell apoptosis were measured by flow cytometry. RESULTS: The strongest inhibition of cytokine secretion was found for IL-10. IL-6 levels were found to decrease in a dose-dependent manner along with reduced cell viability. TNF-alpha levels increased with low gliotoxin exposure (less than 100 ng/mL), but decreased significantly at 375 ng/mL and higher along with increased cell apoptosis and reduced cell viability. TNF-alpha levels were not reduced by citrinin exposure. CONCLUSION: We observed a cytokine imbalance with a more pronounced reduction of IL-10 concentrations compared with those of TNF-alpha and IL-6. We suggest that low exposure doses of citrinin and gliotoxin (corresponding to less than 100 ng/mL gliotoxin and less than 10 mug/mL citrinin) may inhibit IL-10 and lead to increased risk of an inflammatory response with relative overproduction of TNF-alpha and IL-6. The findings and their clinical implications must be verified by human studies. However, we speculate that the observed biological effects may be of importance as they may partly explain the occurrence of diffuse general indoor air-related symptoms as well as the worsening of asthmatic inflammatory reactions experienced in mouldy environments.

Air Pollution, Indoor↗
PubMed1988

Intoxication by tremorgenic mycotoxin (penitrem A) in a dog.

A 1-year-old Siberian Husky dog presented with severe muscle tremors after ingestion of a mouldy hamburger bun. Penicillium crustosum and the tremorgenic mycotoxin penitrem A were isolated from the remaining portion of the hamburger bun. When grown in pure culture, the isolate of P. crustosum produced large amounts of penitrem A, along with other penitrem compounds. This is the first reported Australian case of toxicosis by naturally occurring penitrem A.

Animals↗
PubMed1977

Production of the Tremorgenic Mycotoxins Verruculogen and Fumitremorgin B by Penicillium piscarium Westling.

The tremorgenic mycotoxins verruculogen and fumitremorgin B were isolated from Penicillium piscarium Westling. The coexistence of these tremorgens in culture has previously been reported for one other unrelated fungal species, Aspergillus caespitosus Raper and Thom, and lends further support to the suggestion that the tremorgens have a common biosynthetic origin.

Journal Article↗
PubMed1981

Physiological criteria and mycotoxin production as AIDS in identification of common asymmetric penicillia.

The taxonomy of the asymmetric (predominantly terverticillate) penicillia is based on morphological differences that leave identification difficult. The application of physiological criteria facilitated the identification of the common asymmetric penicillia investigated. Changes in the placement of some strains of these penicillia made the connection to mycotoxin-producing ability clearer. The classical criterion of conidium color was deemphasized and replaced by the following criteria: (i) growth on nitrite-sucrose agar and (ii) growth and acid (and subsequent base) production on creatine-sucrose agar (containing bromocresol purple). Other criteria used or developed were: (iii) growth on sorbic acid plus benzoic acid agar (50 + 50 ppm, pH 3.8), (iv) growth on an agar containing 1,000 ppm propionic acid (pH 3.8), (v) growth on an agar containing 0.5% acetic acid, (vi) growth at 37 degrees C, (vii) growth rate on an agar containing 0.1% pentachloronitrobenzene, (viii) production of extracellular tricaproinase, and (ix) fasciculation on a medium containing 10 ppm botran (2,6-dichloro-4-nitroanilin). The pattern of extracellular metabolites after thin-layer chromatography was used as a chemotaxonomic criterion. The species investigated, the number of isolates investigated, and the toxins which some of these isolates produce were: Penicillium roqueforti (18) (patulin), P. citrinum (11) (citrinin), P. patulum (9) (patulin and griseofulvin), P. expansum (patulin and citrinin), P. hirsutum (13), P. brevicompactum (19), and P. chrysogenum (12). Widespread species of the P. cyclopium, P. viridicatum, and P. expansum series of Raper and Thom (A Manual of the Penicillia, 1949) were subdivided into four new groups: "P. crustosum pA" (29) (penitrem A), "P. melanochlorum" (29), "P. cyclopium p" (119) (penicillic acid and infrequently penitrem A), and "P. viridicatum o-c" (43) (ochratoxin A and citrinin). "P. viridicatum o-c" was separated from "P. cyclopium p" due to its ability to grow on nitrite as sole nitrogen source. The species and groups investigated were related to the new taxonomic classification of the genus Penicillium according to Pitt.

Journal Article↗