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At least 523 records · Page 29Linked to original sources
PubMed2006

Dacthal and chlorophenoxy herbicides and chlorothalonil fungicide in eggs of osprey (Pandion haliaetus) from the Duwamish-Lake Washington-Puget Sound area of Washington state, USA.

Current-use chlorophenoxy herbicides including 2,4-dichlorophenoxyacetic acid, dicamba, triclopyr, dicamba, dimethyl tetrachloroterephthalate (DCPA or dacthal), and the metabolite of pyrethroids, 3-phenoxybenzoic acid (3-PBA), and the fungicide, chlorothalonil, were investigated in the eggs of osprey (Pandion haliaetus) that were collected from 15 sites from five study areas Puget Sound/Seattle area of Washington State, USA. DCPA differs from acidic chlorophenoxy herbicides, and is not readily hydrolyzed to free acid or acid metabolites, and thus we developed a new method. Of the 12 chlorophenoxy herbicides and chlorothalonil analyzed only DCPA could be quantified at six of these sites (2.0 to 10.3 pg/g fresh weight). However, higher levels (6.9 to 85.5 pg/g fresh weight) of the unexpected DCPA structural isomer, dimethyl tetrachlorophthalate (diMe-TCP) were quantified in eggs from all sites. diMe-TCP concentrations tended to be higher in eggs from the Everett Harbor area. As diMe-TCP is not an industrial product, and not commercially available, the source of diMe-TCP is unclear. Regardless, these findings indicate that DCPA and diMe-TCP can be accumulated in the food chain of fish-eating osprey, and transferred in ovo to eggs, and thus may be of concern to the health of the developing chick and the general reproductive health of this osprey population.

2,4-Dichlorophenoxyacetic Acid↗
PubMed2006

Induction and inhibition of cytochrome P450-dependent monooxygenases of rats by fungicide bitertanol.

The effects of fungicide bitertanol on cytochrome P450-dependent monooxygenases were studied using rats treated intraperitoneally with the N-substituted triazole for 4 days. Treatment with 10, 25, and 100 mg/kg bitertanol produced 2-, 4-, and 14-fold increases of 7-ethoxyresorufin O-deethylation activity in liver microsomes, respectively. Immunoblot analysis of microsomal proteins revealed that 25 mg/kg bitertanol increased CYP1A1 protein in the liver, kidney, and lung by 10-, 13-, and 17-fold, respectively. Bitertanol produced smaller increases of CYP2B and CYP3A catalytic activity and protein than that of CYP1A1 in liver. RT-PCR analysis of total RNA indicated that bitertanol-induced CYP1A1, CYP2B, and CYP3A mRNA. Additions of 0.01-100 microM bitertanol to liver microsomes from rats treated with 25 mg/kg bitertanol or 3-methylcholanthrene inhibited microsomal 7-ethoxyresorufin O-deethylation activity (IC(50)=0.8 or 0.9 microM). Bitertanol at 100 mg/kg increased liver UDP-glucuronosyltransferase and glutathione S-transferase activities by 2-fold. Bitertanol at 25 mg/kg produced a minor increase in metabolic activation of benzo[a]pyrene by liver S-9 fraction in the Ames mutagenicity test while the increase was blocked by addition of 100 microM bitertanol. These findings show that bitertanol is an inducer of CYP1A1, CYP2B, and CYP3A in vivo and an inhibitor of CYP1A catalytic activity in vitro.

Animals↗
PubMed2005

Sequence variation in the CYP51 gene of Blumeria graminis associated with resistance to sterol demethylase inhibiting fungicides.

Resistance to sterol 14alpha-demethylase inhibiting fungicides (DMIs) has been correlated with mutations in the CYP51 gene, which encodes the target enzyme eburicol 14alpha-demethylase. To test the hypothesis that variation in the CYP51 gene explains variation for DMI sensitivity in barley and wheat powdery mildew species, this gene was sequenced from isolates of Blumeria graminis f.sp. hordei (Bgh) and f.sp. tritici (Bgt), respectively, which differed in their responses to DMIs in agricultural populations in the UK. Two single-nucleotide mutations in the CYP51 gene, which resulted in the amino acid substitutions Y136F and K147Q, were detected. K147Q is a novel mutation present only in Bgh isolates expressing very high levels of resistance. Sequence analysis of the CYP51 gene from the progeny of a cross between DMI-sensitive and resistant Bgh isolates showed that both mutations segregate with resistance, which is consistent with CYP51 controlling a major portion of DMI resistance. However, genetic analysis of resistance to the DMI triadimenol indicates that mutation of the CYP51 gene is not the only mechanism of resistance operating in B. graminis.

Ascomycota↗
PubMed2006

Dithiocarbamate fungicide thiram detection: comparison of bioluminescent and fluorescent whole-cell bioassays based on hsp22 stress promoter induction.

Detection of toxic substances interfering with endocrine system is one of the major preoccupations of the European community. A whole-cell bioassay for pollution detection based on stress induction has been designed. Well characterized toxicants, cadmium chloride and thiram (a dithiocarbamate fungicide), were used to optimize the detection conditions such as time-course conditions, cell line and reporter gene to be used. HeLa cells containing the firefly luciferase (luc) reporter gene under the control of the Drosophila melanogaster hsp22 promoter were compared to liver cells (HepG2) containing the same stress gene promoter fused either to the luc or the EGFP (Enhanced-Green Fluorescent Protein) gene. The sensitivity of the obtained bioassay was found to be enhanced by the concomitant use of liver cells and EGFP reporter gene. The detection limits of the toxicants were then lowered from 1 to 0.1 microM and from 1 to 0.01 microM for CdCl(2) and thiram, respectively.

Biological Assay↗
PubMed2006

Clastogenicity of the fungicide afugan in cultured human lymphocytes.

The genotoxic effects of the fungicide afugan were analysed by measuring chromosomal aberrations (CAs), sister chromatid exchange (SCE) and micronuclei (MN) in cultured human peripheral lymphocytes. Concentrations of 2.5, 5, 10 and 20 microg/ml of afugan were used during 24 and 48 h. Afugan significantly increased the frequency of CAs at 5, 10 and 20 microg/ml concentrations during a 48 h treatment period. A significant increase was observed for induction of SCE and MN at all treatments compared with the negative control. A significant dose-response correlation was found in all tests. Afugan did not affect the replicative index (RI), however it significantly decreased the mitotic index (MI) at all treatment concentrations except 2.5 microg/ml, and at both treatment times. The present results indicate that afugan is clastogenic and cytotoxic to cultured human lymphocytes.

Cells, Cultured↗
PubMed2003

Behavioral sensitization and long-term neurochemical alterations associated with the fungicide triadimefon.

Triadimefon (TDF), a widely used triazole fungicide, blocks reuptake of the neurotransmitter dopamine (DA), similarly to cocaine. Preliminary studies show that intermittent intraperitoneal injections of TDF increase ambulatory and vertical activity across repeated injections [Neurotoxicology (in press)] leading to the hypothesis tested here, that exposure to TDF may influence the development and expression of behavioral sensitization, a model of psychostimulant-induced psychosis. Exposure of adult male C57BL/6 mice to 75 mg/kg i.p. TDF (TDF75) twice a week for 7 weeks increased vertical activity at each injection. Following a 2-week withdrawal period, a TDF challenge to test for expression of behavioral sensitization revealed further increases in vertical activity levels relative to all other conditions. TDF induction/expression of behavioral sensitization was associated with long-term, perhaps permanent modulation of dopaminergic function that included increases in striatal dihydroxyphenylacetic acid (DOPAC) and DA turnover, increases in medial prefrontal cortex (mPFC) dopamine transporter (DAT) binding, as well as decreases in DA D1 and increases in DA D2 and DAT receptor binding that appeared to target the nucleus accumbens shell (NAs) subregion. Thus, TDF exposure may serve as an environmental risk factor for DA system dysfunctions.

Animals↗
PubMed2006

Postulated pathogenic pathway in triazole fungicide induced dysmorphogenic effects.

Triazole fungicides are used in medicine as well as in agricultural treatment of mycoses. The pharmacological mechanism is related to the inhibition of CYP enzymes involved in the formation of the fungal walls. A similar inhibition of human CYP enzymes has been suggested as the cause of triazole side effects in humans. An important role of some CYP isoforms (CYP26 isoforms) expressed during mammalian development is the catabolism of retinoic acid, a known morphogen in vertebrates and invertebrates. The adverse effects on morphogenesis, observed after exposure of mammalian, amphibian and ascidiacea, are compared to the reported effects of triazole in humans. The possible pathogenic pathway in triazole-related teratogenesis is discussed on the basis of different experimental approaches.

Animals↗
PubMed2006

Effect of conazole fungicides on reproductive development in the female rat.

Three triazole fungicides were evaluated for effects on female rat reproductive development. Rats were exposed via feed to propiconazole (P) (100, 500, or 2500 ppm), myclobutanil (M) (100, 500, or 2000 ppm), or triadimefon (T) (100, 500, or 1800 ppm) from gestation day 6 to postnatal day (PND) 98. Body weight (BW) and anogenital distance (AGD) at PND 0, age and BW at vaginal opening (VO), estrous cyclicity, and body and organ weight at necropsy were measured. BW at PND 0 was unaffected by treatment. AGD was increased by M2000. VO was delayed by M2000 and T1800. Estrous cyclicity was initially disrupted by P500, P2500 and T1800, but later normalized. At PND 99 there was a decrease in BW by T1800, an increase in liver weight by P2500 and T1800, and an increase in ovarian weight by M2000 and T1800. It is concluded that exposure to P, M and T adversely impacted female rodent reproductive development.

Administration, Oral↗
PubMed2004

The effect of developmental exposure to the fungicide triadimefon on behavioral sensitization to triadimefon during adulthood.

Triadimefon (TDF) is a triazole fungicide that acts as an indirect dopamine (DA) agonist by binding to the dopamine transporter (DAT) and increasing levels of synaptic DA. Studies in this laboratory have found that repeated dosing with TDF in adult mice leads to the development and robust expression of behavioral sensitization, a response mediated by dopaminergic and glutamatergic neurotransmitter systems, and causing long-term changes in dopaminergic function. Few studies have focused on the potential for TDF to be a developmental neurotoxicant. As such, the objective of the present study was to determine whether postnatal exposure to TDF would permanently alter DA systems and thereby influence TDF-induced expression of behavioral sensitization during adulthood. Male C57BL/6 mice were dosed intraperitoneally (i.p.) with 25 mg/kg TDF (TDF25), or oil (veh) from postnatal day (PND) 8 to 21. At 8-9 weeks of age, mice were split into four groups and treated with 75 mg/kg TDF (TDF75) or vehicle twice a week for a total of seven injections, with locomotor activity measured immediately after each injection. After a 2-week withdrawal period, mice were further split into eight groups, and challenged with TDF75 or vehicle to test for the expression of behavioral sensitization. Postnatal TDF exposure attenuated both the induction and expression of TDF-induced vertical but not horizontal sensitization in adults. Postnatal TDF exposure also produced long-term decreases in basal striatal dihydroxyphenylacetic acid (DOPAC) levels and nucleus accumbens shell DAT binding. These results indicate for the first time that TDF may be considered an environmental risk factor for developmental dopaminergic neurotoxicity.

Animals↗
PubMed2005

Immunomodulatory effects of the fungicide Mancozeb in agricultural workers.

Available data suggest that ethylenebisdithiocarbamates (EBDCs) may have immunomodulatory effects. This study aimed to investigate the immunological profile of farmers exposed to Mancozeb, an EBDC fungicide, through the determination of several serum, cellular, and functional immune parameters. Twenty-six healthy subjects entered the study, 13 vineyards exposed to Mancozeb and 13 unexposed controls. Exposure was assessed through the determination of ethylentiourea (ETU) in urine. Complete and differential blood count, serum immunoglobulins, complement fractions, autoantibodies, lymphocyte subpopulations, proliferative response to mitogens, natural killer (NK) activity, and cytokine production were measured. Post-exposure samples showed ETU urine concentration significantly higher than pre-exposure and control groups. A significant increase in CD19+ cells, both percentage and absolute number, and a significant decrease in the percentage of CD25+ cells were found in post-exposure samples compared to controls. A statistically significant increase in the proliferative response to phorbol myristate acetate plus ionomycin (PMA + ionomycin) was observed in the post-exposure group compared to controls and baseline, while a significant reduction in LPS-induced TNF-alpha release in post-exposure samples was observed. Overall, our results suggest that low-level exposure to Mancozeb has slight immunomodulatory effects, and point out a method adequate to reveal immune-modifications in workers occupationally exposed to potential immunotoxic compounds, based on a whole blood assay.

Adult↗
PubMed2006

Mechanisms of action underlying the antiandrogenic effects of the fungicide prochloraz.

The fungicide prochloraz has got multiple mechanisms of action that may influence the demasculinizing and reproductive toxic effects of the compound. In the present study, Wistar rats were dosed perinatally with prochloraz (50 and 150 mg/kg/day) from gestational day (GD) 7 to postnatal day (PND) 16. Caesarian sections were performed on selected dams at GD 21, while others were allowed to give birth to pups that were followed until PND 16. Prochloraz caused mild dysgenesis of the male external genitalia as well as reduced anogenital distance and retention of nipples in male pups. An increased anogenital distance indicated virilization of female pups. Effects on steroidogenesis in male fetuses became evident as decreased testicular and plasma levels of testosterone and increased levels of progesterone. Ex vivo synthesis of both steroid hormones was qualitatively similarly affected by prochloraz. Immunohistochemistry of fetal testes showed increased expression of 17alpha-hydroxylase/17,20-lyase (P450c17) and a reduction in 17beta-hydroxysteroid dehydrogenase (type 10) expression, whereas no changes in expression of genes involved in testicular steroidogenesis were observed. Increased expression of P450c17 mRNA was observed in fetal male adrenals, and the androgen-regulated genes ornithine decarboxylase, prostatic binding protein C3 as well as insulin-like growth factor I mRNA were reduced in ventral prostates PND 16. These results indicate that reduced activity of P450c17 may be a primary cause of the disrupted fetal steroidogenesis and that an altered androgen metabolism may play a role as well. In vitro studies on human adrenocortical carcinoma cells supported the findings in vivo as reduced testosterone and increased progesterone levels were observed. Overall, these results together indicate that prochloraz acts directly on the fetal testis to inhibit steroidogenesis and that this effect is exhibited at protein, and not at genomic, level.

Adrenal Cortex↗
PubMed2006

Gene expression profiling in the liver of CD-1 mice to characterize the hepatotoxicity of triazole fungicides.

Four triazole fungicides used in agricultural or pharmaceutical applications were examined for hepatotoxic effects in mouse liver. Besides organ weight, histopathology, and cytochrome P450 (CYP) enzyme induction, DNA microarrays were used to generate gene expression profiles and hypotheses on potential mechanisms of action for this class of chemicals. Adult male CD-1 mice were exposed daily for 14 days to fluconazole, myclobutanil, propiconazole, or triadimefon at three dose levels by oral gavage. Doses were based on previous studies that resulted in liver hypertrophy or hepatotoxicity. All four triazoles caused hepatocyte hypertrophy, and all except triadimefon increased relative liver/body weight ratios at the middle and high dose levels. CYP enzyme activities were also induced by all four triazoles at the middle and high doses as measured by the dealkylations of four alkoxyresorufins, although some differences in substrate specificity were observed. Consistent with this common histopathology and biochemistry, several CYP and xenobiotic metabolizing enzyme (XME) genes were differentially expressed in response to all four (Cyp2d26 and Cyp3a11), or three of the four (Cyp2c40, Cyp2c55, Ces2, Slco1a4) triazoles. Differential expression of numerous other CYP and XME genes discriminated between the various triazoles, consistent with differences in CYP enzyme activities, and indicative of possible differences in mechanisms of hepatotoxicity or dose response. Multiple isoforms of Cyp1a, 2b, 2c, 3a, and other CYP and XME genes regulated by the nuclear receptors constitutive androstane receptor (CAR) and pregnane X receptor (PXR) were differentially expressed following triazole exposure. Based on these results, we expanded on our original hypothesis that triazole hepatotoxicity was mediated by CYP induction, to include additional XME genes, many of which are modulated by CAR and PXR.

Animals↗
PubMed2005

Antiandrogenic effects in short-term in vivo studies of the fungicide fenarimol.

The fungicide fenarimol has estrogenic and antiandrogenic activity and inhibits aromatase activity in vitro. We tested, whether fenarimol had antiandrogenic effects in vivo. In a Hershberger assay, fenarimol given orally to castrated testosterone-treated male rats caused markedly reduced weights of ventral prostate, seminal vesicles, musc. levator ani/bulbocavernosus, and bulbourethral glands. Qualitatively similar, but weaker, effects were also evident in intact fenarimol-exposed young adult males, except that prostates were not significantly affected. Changes in androgen-regulated gene expression were determined by real-time RT-PCR in ventral prostates and fenarimol caused a pronounced decrease of prostate binding protein C3 (PBP C3), ornithin decarboxylase (ODC), and insulin-like-growth factor 1 (IGF-1) mRNA levels. The antiandogenic drug flutamide, included as a positive control, caused down-regulation of PBP C3 mRNA and up-regulation of TRPM-2 mRNA levels. Serum T4 levels were reduced after fenarimol treatment and a tendency towards increased LH levels was seen. However, no effects on testosterone levels or testosterone production ex vivo could be revealed. Taken together these results indicate that fenarimol acts as an antiandrogen in vivo having effects qualitatively comparable to those of flutamide on organ level, whereas differential effects on gene expression were observed. In an additional Hershberger test, the effects of fenarimol were compared to those of estradiol benzoate, prochloraz and the aromatase inhibitor fadrozole. The data indicate a similar mode of action of fenarimol and prochloraz in the males, whereas no indications were found that the estrogenic or aromatase inhibitory properties had important impact on the effects observed in the males. Thus, it is suggested that fenarimol mediates its antiandrogenic effects at least partly via antagonism of androgen receptors.

Androgen Antagonists↗
PubMed2005

Estrogenic effects in vitro and in vivo of the fungicide fenarimol.

The fungicide fenarimol has the potential to induce endocrine disrupting effects via several mechanisms since it possesses both estrogenic and antiandrogenic activity and inhibits aromatase activity in cell culture studies. Hence, the integrated response of fenarimol in vivo is not easy to predict. In this study, we demonstrate that fenarimol is also estrogenic in vivo, causing significantly increased uterine weight in ovariectomized female rats. In addition, mRNA levels of the estrogen responsive gene lactoferrin (LF) were decreased in uteri, serum FSH levels were increased, and T3 levels decreased in fenarimol-treated animals. To our knowledge, only two other pesticides (o,p-DDT and methoxychlor) have previously been reported to induce an estrogenic response in the rodent uterotrophic bioassay. A pronounced xenoestrogenicity in serum samples from rats treated with fenarimol and estradiol benzoate (E2B) separately or in combination was observed, demonstrating the usefulness of this approach for estimating the integrated internal exposure to xenoestrogens. The MCF-7 cell proliferation assay was used to investigate further the dose-response curves for the estrogenic, antiestrogenic, and aromatase inhibiting properties of fenarimol in vitro. The results indicates that fenarimol exhibits a dual effect being aromatase inhibitor at low concentrations and estrogenic at higher concentrations.

Animals↗
PubMed2000

Simplified method for the determination of chlorinated fungicides and insecticides in fruits by gas chromatography.

A fast, reliable method for the determination of more than twenty chlorinated fungicides and insecticides in a variety of fruit samples is presented. The pesticides are extracted from chopped samples with magnetic stirring, after adding 13 ml of acetone-phosphate buffer-brine solution (12:1, v/v) with 5 ml of n-hexane. The continuous module employed allows sequential decolourization of the organic phase, solvent changeover and solid-phase extraction for clean-up and preconcentration purposes. A 1-microl aliquot of the pesticides in ethyl acetate (eluent) is finally injected into the gas chromatograph for separation and identification. The method provides excellent clean-up despite the complexity of the matrices involved. Fruit samples (5-20 g) containing 0.1-1250 ng/g pesticides were analysed with a high precision (4-6%). After contamination of the fruit samples for 12 h, average recoveries >90% at fortification levels of 5-25 ng/g were obtained for most of the pesticides. Positive findings of these pesticides in fruits purchased at local markets were confirmed by GC-MS.

Chromatography, Gas↗
PubMed2002

Solid-phase microextraction-gas chromatographic-mass spectrometric method for the determination of the fungicides cyprodinil and fludioxonil in white wines.

A solid-phase microextraction (SPME) followed by a gas chromatographic-mass spectrometric (GC-MS) determination has been developed and validated for the determination of cyprodinil and fludioxonil in white wine samples. Extraction parameters such as the selection of SPME coating, the effect of the temperature, the effect of the headspace volume and the salt addition were studied and optimized, together with GC-MS analytical conditions. The divinylbenzene-Carboxen-polydimethylsiloxane (DVB-CAR-PDMS) fiber was the most appropriate for the determination of the two pesticides in wine. The quality parameters of the proposed method demonstrated a good precision (RSD about 5%), with detection limits of 0.1 and 0.2 microg/l for cyprodinil and fludioxonil, respectively. Fifteen commercial white wine samples produced in Rías Baixas area in Galicia (N.W. Spain) were analyzed with the SPME-GC-MS procedure. Some of the commercial wines (75%) presented the two pesticides in concentrations ranging from 0.9 to 28.6 microg/l. In conclusion, SPME-GC-MS has a great potential for fungicide determination in wines.

Dioxoles↗
PubMed1996

Determination of the fungicide vinclozolin in honey and bee larvae by solid-phase and solvent extraction with gas chromatography and electron-capture and mass spectrometric detection.

Methods for the determination of residual vinclozolin in honey and bee larvae are proposed. The fungicide can be extracted with an n-hexane-acetone (70:30, v/v) mixture, or by passage through ODS cartridges which requires no subsequent clean-up. Vinclozolin is quantified by capillary gas chromatography with electron-capture and mass spectrometric detection. Recoveries from spiked samples exceed 90%, with a relative standard deviation of 3.5-4.5%.

Animals↗
PubMed1997

Comparison of octadecylsilica and graphitized carbon black as materials for solid-phase extraction of fungicide and insecticide residues from fruit and vegetables.

Methods for the determination of thirteen fungicide and insecticide residues by solid-phase extraction with C18 and graphitized carbon black (GCB) were evaluated. The extraction of the residues was achieved by using matrix solid-phase dispersion (MSPD) and more conventional polar solvent extraction followed by liquid-solid phase partitioning. Determination was carried out by capillary gas chromatography with electron-capture and mass spectrometry detectors. The recoveries were determined by fortifying six different crops (apples, oranges, pears, tomatoes, lettuces and paprikas) with the pesticides studied (bromopropylate, chlorpyrifos methyl, cypermethryn, deltamethryn, fenarimol, fenvalerate, imazalil, lindane, permethryn, phentoate, procymidone, propiconazole and vinclozoline). Although, the data showed that the two extraction methods and both sorbents were able to isolate the pesticide residues from fruit and vegetables, the best results were obtained using MSPD with C18 which gave recoveries ranging from 70 to 105% and practical detection limits between 5.0 and 50.0 micrograms/kg for all the compounds. Ten of these pesticides have been detected in samples taken from Valencia markets, at levels of 0.02-20.50 mg/kg using the described methodology.

Carbon↗