Effects of zearalenone and alpha-Zearalenol in comparison with Raloxifene on T47D cells. (65/185)

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Mycobiota and mycotoxins in fermented feed, wheat grains and corn grains in Southeastern Buenos Aires Province, Argentina. (66/185)

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Transcriptional and post-transcriptional regulation of iNOS expression in human chondrocytes. (67/185)

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Biosynthesis of resorcylic acid lactone (5S)-5-hydroxylasiodiplodin in Lasiodiplodia theobromae. (68/185)

An administration study of (2)H-labeled precursors showed that the 9-hydroxydecanoyl unit, the acyl intermediate of lasiodiplodin (1), was also the intermediate of (5S)-5-hydroxylasiodiplodin (2) in Lasiodiplodia theobromae. The incorporation of [O-methyl-(2)H(3)]-lasiodiplodin (6) into 2 indicated that hydroxylation at C-5 occurred after cyclization.  (+info)

Metabolic conversion of zearalenone to alpha-zearalenol by goat tissues. (69/185)

Zearalenone (ZEA), an estrogenic mycotoxin produced by several Fusarium species, is converted into a more active metabolite, alpha-zearalenol (alpha-ZOL), and a less active metabolite, beta-zearalenol (beta-ZOL), by liver subcellular fractions, but evidence of this reaction in other tissues is limited. In order to clarify the role of various tissues in ZEA metabolism in ruminant, we investigated the in vitro metabolic conversion of ZEA by various tissues of adult male and female goats. The results indicate that in the liver, alpha-ZOL was a major metabolite in cytosolic fractions, whereas beta-ZOL was a predominant metabolite in microsome fractions. Such a feature of ZEA metabolism was confirmed by the K(m) and V(max) values from an enzyme kinetics experiment. Post-mitochondrial fractions of the liver converted ZEA predominantly to alpha-ZOL, indicating that the goat liver may function as an activation organ rather than as an inactivation organ, for ZEA metabolism in goats. In most other tissues including rumen tissue, the activity converting ZEA to alpha-ZOL was higher than that to beta-ZOL. The amount of alpha-ZOL formed by gastrointestinal tissues was 1/8-1/3 of that by the liver tissue in terms of the amount per mg protein, but the contribution of all gastrointestinal tissues to production of alpha-ZOL was estimated to be comparable to that of the liver because of the large mass of gastrointestinal tissues in ruminants. Overall the results show the importance of not only the liver tissue, but also other tissues, especially gastrointestinal ones, in the formation of a potent estrogenic metabolite, alpha-ZOL.  (+info)

Occurrence of microscopic fungi and mycotoxins in conserved high moisture corn from Slovakia. (70/185)

Contamination by microscopic fungi and mycotoxins in high moisture corn (HMC) silages conserved by chemical additives was investigated. The samples were examined for the concentration and identification of microscopic fungi able to grow on Malt and Czapek-Dox agar and for mycotoxins content (deoxynivalenol, T-2 toxin, zearalenone and total aflatoxins, fumonisins, ochratoxins) by direct competitive enzyme-linked immunosorbent assays. The average fungal counts were 3.37 +- 2.52 log cfu/g in control HMC silages, 2.91 +- 0.51 log cfu/g in HMC silages treated by organic salts and inorganic salt, 3.62 +- 1.46 log cfu/g in HMC ensiled with organic acids and 3.49 +- 1.12 log cfu/g of HMC silages treated by organic acids along with organic salt. In this study, 740 isolates belonging to 10 fungal species representing 9 genera were recovered. The genera of microscopic fungi most frequently found in HMC were Penicillium (56.49 percentages) and Paecilomyces (32.16 percentages). T-2 toxin was the secondary metabolite with the highest concentration ranging from 179.13 +- 3.04 to 249.40 +- 24.69 micrograms/kg, followed by deoxynivalenol and total fumonisins. The highest mean of deoxynivalenol level was 0.13 +- 0.02 mg/kg and concentration of total fumonisins ranged from 20.13 +- 2.53 to 90.33 +- 10.35 micrograms/kg. This study indicated that application of chemical additives containing organic acids, organic salts and inorganic salt was sufficient to inhibit mycotoxins formation. The use of calcium formiate, sodium benzoate and sodium nitrite resulted in high hygienic quality of HMC silages and significantly reduced the concentration of zearalenone, deoxynivalenol and total ochratoxins and fumonisins.  (+info)

Cleavage of zearalenone by Trichosporon mycotoxinivorans to a novel nonestrogenic metabolite. (71/185)

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The resorcylic acid lactone hypothemycin selectively inhibits the mitogen-activated protein kinase kinase-extracellular signal-regulated kinase pathway in cells. (72/185)

The resorcylic acid lactone hypothemycin has been shown to inactivate protein kinases by binding to a cysteine conserved in 46 protein kinases, including mitogen-activated protein kinase kinase (MEK), extracellular signal-regulated kinase (ERK) and platelet-derived growth factor receptor (PDGFR). We assessed the selectivity of hypothemycin in cellular contexts. Hypothemycin normalized the morphology and inhibited anchorage-independent growth of Ki-ras transformed normal rat kidney (NRK) cells with selectivity and potency comparable to or greater than that of the MEK inhibitor U0126. In Ki-ras-transformed and phorbol 12-myristate 13-acetate (PMA)-treated NRK cells, hypothemycin blocked ERK activation but showed a minimal effect on autophosphorylation of protein kinase D1 (PKD1), another kinase containing the conserved cysteine. Hypothemycin potently inhibited PDGFR autophosphorylation and activation of the MEK-ERK pathway in platelet-derived growth factor (PDGF)-treated NRK cells. However, the phosphoinositide-3-kinase (PI3K) pathway was only modestly attenuated. Hypothemycin also inhibited growth factor- and anchorage-independent growth of human cancer cell lines with a constitutively active MEK-ERK pathway. Although hypothemycin has the potential to inactivate various protein kinases, the results indicate that in intracellular environments, hypothemycin can inhibit the MEK-ERK axis with sufficient selectivity to normalize transformed phenotypes of cells dependent on this pathway.  (+info)