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PubMed2005

The effects of fungicide benomyl (benlate) on growth and mitosis in onion (Allium cepa L.) root apical meristem.

In this study, the effects of benomyl, a systemic fungicide were investigated in the mitotic cell division in onion (Allium cepa) root tip cells during germination. For this aim, different concentrations (1, 2, 5, 10 and 20 mM) of benomyl solutions were used. All the concentrations used caused several abnormalities in mitotic cell divisions and the mitotic frequency in the onion root tip cells decreased as the concentration of benomyl solution increased. Based on our findings, it is reported that benomyl has some negative effects on mitotic divisions in onion root tip cells.

Benomyl↗
PubMed2000

Effect of fungicide application on activity of Neozygites fresenii (Entomophthorales: Neozygitacaea) and cotton aphid (Homoptera: Aphididae) suppression.

The development of resistance in aphid populations highlights the importance of biological control as a pest management tactic. Four treatments were evaluated to determine the effects of pesticides on the population dynamics of Aphis gossypii Glover and Neozygites fresenii (Nowakowski) Batko: (1) weekly applications of the insecticide imidacloprid (Provado 1.6 F); (2) weekly applications of the fungicide chlorothalonil (Bravo 720); (3) applications of imidacloprid (Provado 1.6 F) when aphid densities exceeded 30 aphids per leaf, and (4) untreated control. Differences in aphid density among the four treatments were shown only to be significant during the 1997 growing season; however, aphid densities were greater in the chlorothalonil treatment than in the other treatments during each growing season. Percentage of N. fresenii-killed aphids was most often highest in the chlorothalonil treatment as well. The fungal epizootic caused by N. fresenii was delayed approximately 1 wk in the chlorothalonil treatment when compared with the other treatments. This delay allowed the aphids to temporarily escape suppression by the fungus and to continue to increase in density until the density-dependent effects of the epizootic overwhelmed the aphid population. N. fresenii also appeared to persist in the system when imidacloprid was in use and does appear responsible for initial aphid reductions. Treatment did not appear to have a large influence on yield outcome. Yield was variable from year to year and from location to location.

Animals↗
PubMed2005

Influence of long-term dietary administration of procymidone, a fungicide with anti-androgenic effects, or the phytoestrogen genistein to rats on the pituitary-gonadal axis and Leydig cell steroidogenesis.

Procymidone is a fungicide with anti-androgenic properties, widely used to protect fruits from fungal infection. Thereby it contaminates fruit products prepared for human consumption. Genistein-containing soy products are increasingly used as food additives with health-promoting properties. Therefore we examined the effects of long-term dietary administration (3 months) of the anti-androgen procymidone (26.4 mg/animal per day) or the phytoestrogen genistein (21.1 mg/animal per day) to rats on the pituitary-gonadal axis in vivo, as well as on Leydig cell steroidogenesis and on spermatogenesis ex vivo. The procymidone-containing diet elevated serum levels of LH and testosterone and, furthermore, Leydig cells isolated from procymidone-treated animals displayed an enhanced capacity for producing testosterone in response to stimulation by hCG or dibutyryl cAMP, as well as elevated expression of steroidogenic acute regulatory protein (StAR), cytochrome P450 side-chain cleavage (P450 scc) and cytochrome P450 17alpha (P450c17). In contrast, the rate of DNA synthesis during stages VIII and IX of spermatogenesis in segments of seminiferous tubules isolated from genistein-treated rats was decreased without accompanying changes in the serum level of either LH or testosterone. Nonetheless, genistein did suppress the ex vivo steroidogenic response of Leydig cells to hCG or dibutyryl cAMP by down-regulating their expression of P450 scc. Considered together, our present findings demonstrate that long-term dietary administration of procymidone or genistein to rats exerts different effects on the pituitary-gonadal axis in vivo and on Leydig cell steroidogenesis ex vivo. Possibly as a result of disruption of hormonal feedback control due to its anti-androgenic action, procymidone activates this endocrine axis, thereby causing hyper-gonadotropic activation of testicular steroidogenesis. In contrast, genistein influences spermatogenesis and significantly inhibits Leydig cell steroidogenesis ex vivo without altering the serum level of either LH or testosterone.

Administration, Oral↗
PubMed2005

Influence of sediment quality on the responses of benthic invertebrates after treatment with the fungicide triphenyltin acetate.

After decades of pollution, benthic communities in floodplain lake ecosystems are likely to be exposed to a diverse assortment of sediment-bound historical toxicants and nutrients as well as pulses of newly discharged or deposited toxicants. The aim of this study was therefore to analyze the effects of background sediment pollution on the responses of benthic invertebrates to an experimental toxic shock in a laboratory setting. Sediment from a relatively clean and a historically polluted floodplain lake located along the River Waal, a branch of the River Rhine, The Netherlands, was selected, and the fungicide triphenyltin acetate (TPT) was used as the acute stressor. Juvenile stages of the mayfly Ephoron virgo and the midge Chironomus riparius were chosen as test organisms because of their different response to sediment-bound toxicants and food quantity and quality. Our results demonstrated that the type of sediment had no effect on survival and growth of C. riparius when exposed to sediment-associated TPT and that E. virgo was more affected by sediment-associated TPT on clean sediment than on polluted sediment. For the mayfly, no cumulative response of the historical pollution and the recent toxic shock was observed. This observation is discussed in view of the variable content of organic matter, acting both as food and as sorbent, and leads to the hypothesis that a very strong sequestering of TPT in historically polluted sediment prevents expression of toxic effects.

Animals↗
PubMed2001

Effects of fungicides on thyroid function, metabolism, and thermoregulation in cotton rats.

Among the myriad of recent studies on endocrine-disrupting chemicals, relatively few involve thyroid disruption, and most of these address exposure/disruption during embryonic life. Of those involving adult vertebrates, the endpoints examined are thyroid measurements. Even though thyroid disruption could potentially interfere with energy metabolism and thermoregulation such that over-winter survival might be compromised, the possible energetic consequences of these thyroid perturbations have not been investigated. We assessed thyroid function and measured resting metabolic rates of cotton rats chronically exposed to the fungicides vinclozolin or mancozeb. In addition, we measured norepinephrine-induced nonshivering thermogenesis and cold-induced thermogenesis and then cold-acclimated the mancozeb animals. Although thyroid hormone concentrations generally decreased, this was compensated for by an increase in thyroxine turnover (vinclozolin study only) such that thyroxine utilization rate was not different. In addition, there was no difference between the treated and control animals in any of the metabolic parameters measured. It is concluded that wild rodents exposed to these compounds are not energetically compromised.

Animals↗
PubMed2002

LC/MS studies on characterization and determination of N,N'-ethylenebisdithiocarbamate fungicides in environmental water samples.

Liquid chromatography/mass spectrometry (LC/MS) has been applied to analyze N,N'-ethylenebisdithiocarbamate fungicides (EBDCs: manzeb, maneb and zineb) in environmental water samples. The EBDCs that are zinc and/or manganese salts are transformed into readily water-soluble sodium salts by adding an alkaline EDTA solution. The N,N'-ethylenebisdithiocarbamate anion is extracted into chloroform-hexane (3:1) as an ion pair with tetrabutylammonium, and then S-alkylated with methyl iodide. The extraction and derivatization are carried out at room temperature. The derivatized ethylenebisdithiocarbamic acid dimethyl ester is introduced into an LC/MS equipped with a negative ion electrospray ionization interface. Identification of the compound is performed with the specific quasi-molecular ion, and the quantitative analyses are carried out using the peak areas. The average recoveries and coefficients of variation of EBDCs at sub-ppb level are 79.1% and 29.3% (n = 6), respectively. The limit of detection based on standard deviation of 0.043 microg/L for manzeb is achieved.

Calibration↗
PubMed2002

Anti-implantation effect of a carbamate fungicide mancozeb in albino mice.

Mancozeb, an organocarbamate fungicide, was administered to examine the effect on implantation at doses of 18, 24, 30 and 36 mg/kg body weight/d to normal virgin swiss albino mice for 8 days to pregnant mice. The vaginal smear and body weight of the mice were recorded daily and mice were sacrificed on 9th day of pregnancy. There was a complete inhibition of implantation in 36 mg mancozeb treated mice with 100% pre-implantation loss. There was a partial inhibition of implantation in 24 and 30 mg mancozeb treated mice with 53.44 and 90.16% pre-implantation loss respectively. However, implantation was not affected in 18 mg mancozeb treated mice with 4.92% pre-implantation loss when compared to oil treated controls. To study the temporal effect, the effective dose of 36 mg/kg body weight/d mancozeb was administered orally for 3 and 5 days and on day 3 only. There was a complete inhibition of implantation in 5 days treated mice with 100% pre-implantation loss and partial inhibition of implantation of 3 days treated mice with 75% pre-implantation loss. However, implantation was not affected in mice treated on day 3 only with 1.63% pre-implantation loss when compared to control mice. There was a significant decrease in the diestrus phase with the result there was a concomitant increase in the estrus phase and there was a significant decrease in the uterus weight with 24, 30 and 36 mg and for 3 and 5 days with 36 mg mancozeb treatment. Inhibition of implantation by mancozeb may be due to hormonal imbalance or its toxic effects.

Animals↗
PubMed1989

Effects of the fungicide prochloraz on xenobiotic metabolism in rainbow trout: inhibition in vitro and time course of induction in vivo.

1. Interactions between the fungicide prochloraz and the hepatic cytochrome P-450 of rainbow trout were studied by determination of enzymic activities in vitro using the microsomal fraction, and by kinetic studies. 2. Prochloraz inhibited 7-ethoxyresorufin-O-deethylase (EROD) in vitro. This inhibition was partially non-competitive: the enzyme-substrate-inhibitor (ESI) complex was catalytically active (68% of the activity of the enzyme-substrate complex). 3. Prochloraz in vitro inhibited aldrin epoxidase (AE) by a linear mixed-type mechanism. This inhibition might be high because of high affinity for prochloraz and lack of catalytic activity of the ESI complex. 4. Effects of prochloraz in vivo were studied as a function of time after intraperitoneal injection. Total cytochrome P-450 increased for more than 21 days. 5. EROD increased slightly at day 4 and then returned to control level. Kinetics showed an increase in apparent Km and Vmax. AE was strongly inhibited at day 4 (large increase in apparent Km) and then returned to control level in 21 days. 6. Spectral interactions with aniline showed strong inhibition and recovery to an activated level at day 21.

Animals↗
PubMed2006

Residues of the quinone outside inhibitor fungicide trifloxystrobin after postharvest dip treatments to control Penicillium spp. on citrus fruit.

The effectiveness of postharvest dip treatment with trifloxystrobin (TFX) or imazalil (IMZ) was compared for controlling green and blue mold (caused by Penicillium digitatum and Penicillium italicum, respectively) of citrus fruit. Residues retained by fruit were determined as a function of treatment time, dip temperature, and storage conditions. Trials on 'Avana apireno' mandarin oranges artificially inoculated with P. digitatum or P. italicum revealed that treatments with 200 to 600 mg/liter active ingredient TFX at 20 degrees C were less effective than 100 mg/liter TFX at 500C for controlling P. digitatum but equally effective for controlling P. italicum. IMZ treatments with 200 mg/liter IMZ at 20 degrees C or 25 mg/liter IMZ at 50 degrees C resulted in more than 98% reduction of P. digitatum and ca. 93% reduction of P. italicum compared with untreated fruit. Total suppression of pathogens was achieved when higher IMZ doses were applied. Studies on artificially wounded lemons, oranges, clementines, and mandarins revealed that treatment with 100 mg/liter TFX at 50 degrees C effectively controlled decay development (mainly due to P. digitatum) after 7 days of storage at 20 degrees C. These results were confirmed on nonwounded oranges of cv. Tarocco and on grapefruits of cvs. Marsh Seedless and Star Ruby during 3 weeks of simulated quarantine at 1 degrees C, storage (5 weeks at 8 degrees C for oranges and 8 weeks at 11degrees C for grapefruits), and an additional 1 week of simulated marketing conditions at 20 degrees C. IMZ at 50 degrees C was highly effective for controlling decay during storage and the simulated marketing period. TFX treatment at 50 degrees C was as effective as IMZ for controlling decay in most samples. After treatment with 100 mg/liter TFX at 20 degrees C, fungicide residues in 'Tarocco' oranges doubled from 0.15 mg/kg to 0.30 mg/kg when dip time increased from 0.5 to 3 min, whereas when treatments were performed at 50 degrees C TFX residues were not related to dipping time. Residues of TFX were significantly correlated with dip temperature. A 3-min dip treatment at 50 degrees C resulted in a deposition of TFX that was approximately twofold higher than that obtained when treatments were carried out at 20 degrees C.

Acetates↗
PubMedDate not supplied

[The mutagenic potential of the fungicide thiram].

Chemical products used in agriculture require detailed formulation and knowledge on their mode of action and uses. This is essential for understanding the pesticide's biological behavior and also to establish safety criteria for humans and animals. At the present time, there are numerous studies concerning physical and chemical agents present in the media which increase the incidence of tumors. In this paper, we demonstrate the mutagenic capacity of the fungicide thiram, using the microbiological Ames test, at a concentration of 1 mg/ml active ingredient in the culture medium. Higher concentrations were lethal to the microorganisms used in the test.

Animals↗
PubMedDate not supplied

Multiresidue determination of 19 fungicides in processed fruits and vegetables by capillary gas chromatography after gel permeation chromatography.

A gas chromatographic (GC) method was developed for simultaneous determination of 19 fungicides (chlorothalonil, vinclozolin, dichlofuanid, triadimefon, penconazole, chlozolinate, captan, procymidone, triadimenol, folpet, hexaconazole, myclobutanil, cyproconazole, propiconazole, nuarimol, captafol, iprodione, fenarimol, and bitertanol) and the acaricide tetradifon in tomato puree, peach nectar, orange juice, and canned peas. Samples were extracted with acetone, partitioned with ethyl acetate-cyclohexane (50 + 50, v/v), and cleaned using gel permeation chromatography with ethyl acetate-cyclohexane (50 + 50, v/v) as eluant. The final extract was analyzed by GC with ion trap mass spectrometry (ITMS) using a DB5 capillary column. Recoveries from fortified samples ranged from 74.6 to 99.3%, except for triadimenol and bitertanol. Quantitation limits for most analytes were between 0.005 and 0.050 mg/kg. The purified extracts were analyzed further by GC with electron capture and nitrogen phosphorus detection, and the results were compared with those obtained by ITMS.

Chromatography, Gas↗
PubMed2001

Transplacental carcinogenic potential of the carbamate fungicide mancozeb.

We evaluated the effects of mancozeb (Dithane M4-5), a protective carbamate fungicide, on transplacental carcinogenesis in Swiss albino mice. Mancozeb, a polymeric complex of ethylene bis (dithiocarbamate) manganese with zinc salt, is reported to possess carcinogenic and cocarcinogenic activity in various tumor models. In the present study, pregnant Swiss albino mice were administered mancozeb intraperitoneally on the 14th day of gestation. The first filial generation (F1 progeny) was promoted with a well-known tumor promoter 12-o-tetradecanoyl phorbol-13-acetate (TPA). The results revealed a significantly high tumor incidence (72%) in the F1 progeny of the animals initiated with mancozeb or a well known carcinogen 7,12-dimethyl benzanthracene (DMBA) and promoted with TPA in comparison to animals that were either from mothers given only the vehicle (DMSO) and promoted with TPA in F1 progeny or not promoted with TPA in F1 progeny. No significantly higher tumor incidence was observed in any other experimental groups. These results suggest that mancozeb or its metabolites are capable of crossing the placental barrier and can exert DNA damage and tumor initiating consequences in the fetal cells that, after promotion with TPA, get converted into neoplastic cells.

9,10-Dimethyl-1,2-benzanthracene↗
PubMedDate not supplied

Monitoring of five postharvest fungicides in fruit and vegetables by matrix solid-phase dispersion and liquid chromatography/mass spectrometry.

A method was developed for monitoring dichloran, flutriafol, o-phenylphenol, prochloraz, and tolclofos-methyl in fruits and vegetables, using matrix solid-phase dispersion and liquid chromatography with mass spectrometry detection. The method was used to determine fungicide content in 200 samples of chards, onions, peppers, bananas, lemons, and oranges. Of the samples examined, 54% contained o-phenylphenol with concentrations ranging from 0.005 to 3.34 mg/kg and 35% showed prochloraz in the range of 0.06-1.95 mg/kg. Dichloran, flutriafol, and tolclofos-methyl were detected only occasionally. Only 4% of the samples exceeded the European Union maximum residue limits. The pesticides involved were tolclofos-methyl in 3 samples, o-phenylphenol and flutriafol in 2, and dichloran in one. The calculation of estimated daily intake from these monitoring data showed that dietary intakes were much lower than the acceptable daily intakes established by international agencies.

Chromatography, Liquid↗
PubMed2002

Inherent and growth stage-related differences in growth and lipid and sterol composition of algal species sensitive and tolerant to sterol-inhibiting fungicides.

Fourteen algal species representing five algal classes were evaluated as to the effects of four sterol-inhibiting fungicides (SIFs) on growth. Sensitivity to SIFs was related to species, chemical, and concentration. Species of Chlorella sensitive and tolerant to SIFs were further compared relative to inherent and growth stage-related differences in lipid, free sterol (FS), and steryl ester (SE) composition. Inherent and growth stage-related qualitative and quantitative differences in FS and SE composition were apparent between the two species examined. The qualitative FS and SE composition was particularly different. The importance of lipids, FS, and SE in membrane structure and control of membrane function is well established. Species differences and environmentally (growth stage, light, temperature, and nutrition) induced changes in lipid composition may be part of the basis for sensitive and tolerant responses to SIFs and xenobiotics in general. The ability of lipophilic xenobiotics to partition into membranes most likely depends on the qualitative and quantitative composition of membrane components, at any given time, and seems to be highly dynamic. Although the biochemical mechanism of action of SIFs is well established, the ability for passive bioaccumulation of such compounds in algae may be equally as important.

Drug Resistance↗
PubMed2002

Molluscicidal effect of fungicide, herbicide and plant extract on some biological and physiological parameters of Biomphalaria alexandrina.

In was found that the exposure of B. alexandrina to LC25 of fungicide (Isoprothiolane), herbicide (Anilofos) and plant extract (Euphorbia lactea) led to highly significantly elevated in the number of abnormal egg masses laid by treated snails in comparison with the control ones. The LC25 caused reduction in infection rate of B. alexandrina. It caused reduction in number of cercariae per snail during the patent period and reduction in the period of cercarial shedding. The results obtained showed that adenosine triphosphatase (ATPase) activity of tissue of snails was significantly increased in response to tested substances. The activity level of lactate dehydrogenase (LDH). pyruvate kinase (PK) and phosphoenolpyruvate carboxy kinase (PEPCK) was significantly reduced in response to treatment. This reduction does not reflect on both D. lactate and pyruvate concentrations.

Animals↗
PubMedDate not supplied

Acute and long-term effects of a single dose of the fungicide carbendazim (methyl 2-benzimidazole carbamate) on the male reproductive system in the rat.

The effects of carbendazim (methyl 2-benzimidazole carbamate) on the testis, efferent ductules, and sperm were determined in the adult rat after a single oral dose. Two experimental trials were performed: a time response between 2 hours and 32 days after exposure using 0 and 400 mg/kg, and a dose response at 2 and 70 days after exposure using 0 to 800 mg/kg doses. In experiment 1, effects were seen throughout the 32-day period, beginning 8 hours after exposure; the effects included first an increase in testis weight, then decreases in testicular spermatid numbers and in the percentage of morphologically normal cauda sperm. In experiment 2, significant testicular and efferent ductal alterations occurred in animals treated with doses of 100 mg/kg or greater. A dose-dependent increase in testicular weight 2 days after treatment was accompanied by increases in seminiferous tubular diameter and excessive loss of immature germ cells in a stage-dependent manner. There was also a dose-dependent increased incidence of occlusions in the efferent ductules. The occluded ductules were characterized by severe inflammation and exhibited disorganization of the epithelium. At 70 days, there were dose-dependent decreases in mean testis weight and mean seminiferous tubular diameter; however, only minimal long-term effects were seen at 50 mg/kg. In testes exhibiting seminiferous tubular atrophy of greater than 25% (100 mg/kg or greater doses), all of the testes were associated with efferent ductules containing occlusions. Caput sperm numbers were significantly reduced in these testes. Occlusions, abnormal ductules, fibrosis, spermatic granulomas, and mineralization were observed in the ductuli efferents. Long-term effects of carbendazim on the testis were induced primarily by ductal occlusions. Results show that carbendazim produces more severe short- and long-term effects on the male reproductive system than the fungicide benomyl.

Administration, Oral↗
PubMed1992

[Studies on metabolism of fungicide benzoic acid, 1,3-dithiolan-2-ylidenehydrazide in vitro].

The metabolism of fungicide benzoic acid, 1,3-dithiolan-2-ylidenehydrazied (Yekuling) was studied quantitatively in rat liver microsomes and liver soluble fractions pretreated with phenobarbital (PB) and 3-methylcholanthrene (3-MC) by high pressure liquid chromatography. The experimental results indicated that the major metabolic pathway of Yekuling in vitro was hydrolysis. PB can enhance amidase activity to increase formation of benzoic acid and 1,3-dithiolan-2-ylidenehydrazine. 3-MC treatment elevated rat liver microsomal cytochrome P-448, enhancing S-oxidation of Yekuling. On the other hand, S-oxidation of Yekuling by rat liver microsomal MFO was NADPH-dependent.

Animals↗