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PubMed1982

Inhibition of DNA polymerase by captan.

Captan inhibits DNA polymerases of both eukaryotic and prokaryotic sources. When polymerases were employed in assays with various nucleotides as template-primer, no specificity in the base sequence of polynucleotide was required for inhibition. Sucrose gradient centrifugation and preincubation studies showed the inhibition was caused by an irreversible alteration of the polymerase. Captan and DNA compete for the same site on the polymerase, thus DNA can serve a protective role in the elimination of captan's action. The pyrophosphate exchange activity associated with the polymerase is not inhibited by captan and the fidelity with which DNa polymerase I copies the DNA template also is not altered by captan treatment.

Animals↗
PubMed2003

Permeation of captan through disposable nitrile glove.

The purpose of this study was to investigate the permeation of an aqueous emulsion of the pesticide, captan, as a wettable powder (48.9% captan) through a disposable nitrile glove material using an American Society for Testing and Materials (ASTM)-type I-PTC-600 permeation cell. The goal was to investigate the protective capability of the gloves against dermatitis. The analytical method was based on gas chromatography-mass spectrometry (GC-MS) and gas chromatography-electron capture detection (GC-ECD). The least quantifiable limit (LQL) was 6 ng for GC-ECD and 30 ng for GC-MS. Testing was conducted using the ASTM F739 closed-loop permeation method and a worst-case aqueous concentration 217 mg/ml of captan 50-WP. The average permeation rates were low, with 12+/-5 ng/(cm(2)min) after 2h, 50+/-25 ng/(cm(2)min) after 4h, and 77+/-58 ng/(cm(2)min) after 8h. The calculated diffusion coefficient was (1.28+/-0.10) x 10(-5)cm(2)/h. No significant swelling or shrinkage occurred at P</=0.05. Infrared (IR) reflectance analysis of pre- and post-exposure glove surfaces confirmed no outer or inner surface degradation. The disposable nitrile glove showed excellent resistance to a highly concentrated aqueous emulsion of captan. Because the ASTM normalized breakthrough detection time of 250 ng/cm(2) was <2h, these gloves should not be reused once worn, and decontamination is not advised. Protection is also advised for agricultural reentry field workers, because captan has been shown to persist on crops with a half-life greater than the current reentry intervals of 1-4 days.

Captan↗
PubMed1988

Involvement of glutathione in the reduction of captan-induced in vivo inhibition of monooxygenases and liver toxicity in the rat.

If given orally captan is relatively nontoxic, but it can be extremely toxic after parenteral exposure. Therefore, a single i.p. dose of captan (20 mg/kg) was given to male Sprague-Dawley rats and its effect on liver microsomal mixed function oxidases and certain serum enzymes (SDH, SGPT and SGOT) was studied. The single dose of captan caused marked depression of microsomal cytochrome P-450 and the activity of benzphetamine N-demethylase and aniline hydroxylase, and moderate elevation of the serum enzymes indicative of liver damage. However, reduced glutathione (100 mg/kg, i.p.) given prior to captan, appears to decrease the liver toxicity as measured by reduced inhibition of the microsomal enzymes and elevation of serum enzymes activity. The results suggest that glutathione and other compounds containing sulfhydryl groups may protect the subjects from captan-induced liver toxicity.

Animals↗
PubMedDate not supplied

[Effect of the fungicide captan on Azospirillum brasilense Cd in pure culture and associated with Setaria italica].

The effect of fungicide captan on growth and nitrogenase activity of Azospirillum brasilense Cd was studied in pure cultures and in association with foxtail millet (Setaria italica) cultivar Carapé under laboratory conditions. The 8 h growth in rotary shaker of A. brasilense was inhibited with 1 mg/l pure captan; however, after 4 days the differences diminished compared with the control without captan. Nitrogenase activity was affected with 10 mg/l but the differences were negligible after 48 h of growth. Root dry weight of inoculated plants was diminished by the treatment of foxtail millet cv. Carapé with captan. Inoculation with A. brasilense Cd increased shoot dry weight, but differences were significant only with respect to the control but not in relation to captan treatments.

Animals↗
PubMed1976

Effects of the herbicide 2,4-DB and fungicide captan on reactions of mitochondria and chloroplasts.

The effects of the herbicide 4(2,4-dichlorophenoxy)butyric acid (2,4-DB) and fungicide N-(trichloromethyltio)-4-cyclohexene-1,2-dicarboximide (captan) on electron transport processes of mitochondria and chloroplasts have been investigated. Chloroplasts, isolated from spinach leaves (Spinacia oleracea L.), were treated with pesticide prior to the addition of electron acceptor and ADP. White potato (Solanum tuberosum L.) mitochondria were either incubated with pesticide before the addition of substrate, or they were treated with pesticide after the addition of substrate and ADP. Captan inhibited oxidation of malate by mitochondria and acted as an uncoupler. With succinate as sunstrate captan was found to stimulate state 4 respiration, as substrate captan was found to stimulate state 4 respiration, with the loss of coupled phosphorylation only at higher concentrations of fungicide. The herbicide 2,4-DB appeared to be 5 to 10 times less effective than captain. Both compounds inhibited phosphrylation-coupled succinate oxidation at higher concentrations and malate-coupled phosphorylation at lower concentrations. They acted as inhibitors of NADH-cytochrome c reductase. Both pesticides inhibited noncyclic electron transport in chloroplasts. The rate of ferricyanide reduction in the presence and absence of phosphorylating agents was reduced, and although the rate of ATP generation was reduced also, the P/2e ratio was not changed much under the influence of pesticides.

Butyrates↗
PubMed1978

Personnel safety and foliage residue in an orchard spray program using azinphosmethyl and captan.

Residue levels of azinphosmethyl and captan were determined from blotter paper patches attached to the clothing of personnel participating in an orchard spray program. Average exposure of 1.74 mg/man/hr for azinphosmethyl and 1.94 mg/man/hr for captan were extrapolated from mean residue values obtained from analyzing the patches. Azinphosmethyl residue found on apple and peach foliage had been reached by 69% by the tenth day post-application, while captan residue had been reduced 50% for the same period. There was no evidence of a buildup of either azinphosmethyl or captan on treated foliage as the season progressed.

Agricultural Workers' Diseases↗
PubMed2000

Captan fungicide exposures of strawberry harvesters using THPI as a urinary biomarker.

Clothing affords harvesters considerable protection against the elements and can retain substantial amounts of pesticide residue from treated crops. Normal work clothing of female harvesters was supplemented with rubber latex gloves and facial scarves to determine whether those measures reduced exposure. Captan fungicide exposures in female strawberry harvesters were assessed by determining urine clearance rates of tetrahydrophalimide (THPI). Clean rubber gloves were supplied to the 41 harvesters for the 3 days of the study period in October 1995. The workers were divided into two groups consisting of either bare-handed or gloved workers, and 24-h urine specimens were collected each day. Female harvesters who worked bare-handed cleared 5.3 microg captan equivalents as THPI with a range of 0.4 to 13.8 microg/person/day. Harvesters who worked wearing rubber latex gloves cleared only 2.0 microg captan equivalents with a range of 0.9 to 4.3 microg/person/day. In this case clean rubber latex gloves reduced absorbed dose by 38%, compared to the dose absorbed by bare-handed workers. These results additionally indicate that when a pesticide is avidly retained by rubber latex gloves and not readily absorbed dermally as captan, estimates of absorbed dose based on passive dosimetry data may be less reliable than exposure estimates derived from urine biomonitoring.

Administration, Cutaneous↗
PubMed1978

Cytogenetic and dominant lethal studies on captan.

Possible mutagenic activity of captan was investigated by in vitro and in vivo cytogenetic studies and by the dominant lethal study in mice. In vitro cytogenetic study with cultured human diploid cells revealed a significant increase in the frequency of cells showing stickiness and a severe mitotic inhibition at concentrations of 3.0 and 4.0 microgram of captan per ml. although no chromosomal aberrations were observed. In in vivo cytogenetic study, no chromosomal aberrations were induced in the bone marrow cells of rats treated orally with captan at a single dose of 500, 1000 or 2000 mg/kg or at five consecutive doses of 200, 400 or 800 mg/kg/day. Dominant lethal study also failed to show any mutation induction after treatment of male mice with daily oral dose of 200 or 600 mg of captan per kg bw for five days.

Animals↗
PubMed1992

Evidence of reduced poly-B-hydroxybutyrate biosynthesis in free-living nitrogen-fixing bacteria, Azotobacter chroococcum, following acquired resistance to the fungicide captan.

Some biological activities of Azotobacter chroococcum, strain Azcap 1, (spontaneous mutant, captan resistant up to 300 micrograms/ml) were assayed on RM medium with and without the presence of the fungicide. Comparisons were also carried out with Az. chroococcum sensitive strains Azwt, Azcan 10 and 14. The hydrolysis of captan, incorporated in agar plates of RM at 100 micrograms/ml, was rapid, since on 4-day plates, no effect was found on the strain Azwt, while on freshly prepared ones its growth was completely blocked. As for Azcap 1, grown on RM only, the behaviour was similar to that of sensitive strains, whereas when grown on captan the results of experiments showed: (i) a lag of approximately 12 h to reach the maximum nitrogen-fixing activity; (ii) delay of 12-24 h in the full consumption of glucose present in the medium, although the invertase activity did not present differences; (iii) high ATP culture content during the 50 h of the experiment; (iv) approximately 6-10-fold lower production of PHB (poly-B-hydroxybutyrate); (v) lack of typical encystment phase, for the tested 96 h and reduced viability in developing colonies on agar RM medium. In contrast, when captan was added to cultural medium at sublethal concentration, 50 micrograms/ml for sensitive strain Azwt and 200 micrograms/ml for Azcap 1, the amount of glutathione produced (to remove the fungicide toxicity) was several times higher for the former.

Azotobacter↗
PubMed1999

Captan impairs CYP-catalyzed drug metabolism in the mouse.

To investigate whether the fungicide captan impairs CYP-catalyzed drug metabolism in murine liver, kidney and lung, the modulation of the regio- and stereo-selective hydroxylation of testosterone, including 6beta-(CYP3A), 6alpha-(CYP2A1 and CYP2B1) and 16alpha-(CYP2B9) oxidations was studied. Specific substrates as probes for different CYP isoforms such as p-nitrophenol (CYP2E1), pentoxyresorufin (CYP2B1), ethoxyresorufin (CYP1A1), aminopyrine (CYP3A), phenacetin and methoxyresorufin (CYP1A2), and ethoxycoumarin (mixed) were also considered. Daily doses of captan (7.5 or 15 mg/kg b.w., i.p.) were administered to different groups of Swiss Albino CD1 mice of both sexes for 1 or 3 consecutive days. While a single dose of this fungicide did not affect CYP-machinery, repeated treatment significantly impaired the microsomal metabolism; in the liver, for example, a general inactivating effect was observed, with the sole exception of testosterone 2alpha-hydroxylase activity which was induced up to 8.6-fold in males. In vitro studies showed that the mechanism-based inhibition was related to captan metabolites rather than the parental compound. In the kidney, both CYP3A- and CYP1A2-linked monooxygenases were significantly induced (2-fold) by this pesticide. Accelerated phenacetin and methoxyresorufin metabolism (CYP1A2) was also observed in the lung. Data on CYP3A (kidney) and CYP1A2 (kidney and lung) induction were corroborated by Western immunoblotting using rabbit polyclonal anti-CYP3A1/2 and CYP1A1/2 antibodies. By means of electron spin resonance (EPR) spectrometry coupled to a spin-trapping technique, it was found that the recorded induction generates a large amounts of the anion radical superoxide (O*2-) either in kidney or lung microsomes. These findings suggest that alterations in CYP-associated activities by captan exposure may result in impaired (endogenous) metabolism as well as of coadministered drugs with significant implications for their disposition. The adverse outcomes associated to CYP changes (e.g. cotoxicity, comutagenicity and promotion) may also have harmful consequences.

Animals↗
PubMed2002

The inhibitory effect of the fungicides captan and captafol on eukaryotic topoisomerases in vitro and lack of recombinagenic activity in the wing spot test of Drosophila melanogaster.

In studies on the mechanisms of mutagenic and carcinogenic action of captan and captafol-related chloroalkylthiocarboximide fungicides, two effects were tested: (i) the effect of both compounds on the activity of eukaryotic topoisomerases I and II in vitro, and (ii) their mutagenic and recombinagenic activity in the somatic mutation and recombination test (SMART) in wing cells of Drosophila melanogaster. Only captafol inhibited the activity of topoisomerase I (10-20% inhibition of activity in the range of 10-100microM). In contrast, both chemicals decreased the activity of topoisomerase II already at 1microM concentration (50 and 20% inhibition of activity by captafol and captan, respectively).Genotoxicity was tested in vivo by administrating both compounds by acute (3h) and chronic feeding (48h) of 3-day-old larvae. In acute feeding, captan and captafol demonstrated positive results only for small single and total spots in 10-100mM exposure concentration range. Both chemicals were inconclusive for large single spots, as well as for twin spots. In chronic treatment, captan showed positive results only for small single and total spots at 2.5 and 5mM concentrations. Captafol gave inconclusive results over all concentrations tested. The results of the acute treatment experiments which have been performed at very high doses (50% toxicity at higher doses) indicate very weak overall mutagenic activity of both test fungicides.

Animals↗
PubMed2006

Residue levels of captan and trichlorfon in field-treated kaki fruits, individual versus composite samples, and after household processing.

The dissipation of residue levels of captan and trichlorfon in field-treated kaki crops was studied according to good laboratory practices to propose maximum residue limits (MRLs). Residue levels of captan and trichlorfon were analysed by GC/MS and LC-MS/MS, respectively. Residue levels of captan and trichlorfon permitted one to propose MRLs in kaki of 3 and 5 mg kg(-1), respectively. The behaviour of these residues was also studied after peeling and cooking, and in individual fruits versus composite samples. Residue levels of these compounds for individual fruits suggested that a variability factor up to three could be set for the acute risk assessment. Levels of captan decreased by more than 90% after peeling and completely after cooking. Trichlorfon penetrates into the flesh in a proportion of 70% of the residue at the pre-harvest interval. Cooking resulted in a decrease of 27% of residue levels of trichlorfon.

Captan↗
PubMed1979

Alterations of nucleic acid and protein syntheses in vivo in the chick embryo mediated by captan.

1. The objective of this investigation was to measure the effects of captan on DNA, RNA and protein biosyntheses in limbs of developing chick embryo, in vivo. 2. Captan (12p.p.m.) was injected into the egg on day 4 of incubation and macromolecular syntheses were measured on days 8--14. 3. Total DNA content was unaffected by captan, but incorporation of [3H]thymidine was inhibited over the entire time range; the period of peak specific activity (day 11) was inhibited in treated samples to 67% of control. 4. Total RNA content was reduced in the earlier days but returned to normal by day 14, whereas incorporation of [3H]uridine was lowered throughout the period. The timing of peak specific activity for RNA synthesis was delayed by 2 days in treated eggs and was inhibited by 32% when peak days were compared. 5. Total protein concentration was slightly lowered by captan treatment in the mid-range of the days measured and the incorporation of [3H]valine was retarded in the early days; peak periods of synthesis were similar in magnitude but were shifted from days 9--10 in control to day 11 in treated embryos.

Animals↗
PubMed1992

Relative toxicity of aldrin, fenvalerate, captan and diazinon to the freshwater food-fish, Clarias batrachus.

The median lethal concentrations (LC50S) of aldrin, fenvalerate, captan and diazinon were determined for Clarias batrachus by trimmed Spearman-Karber method. The potency ratios of toxicity among them were analysed by parallel-line bioassay with quantal responses. The LC50S for 40 day of exposure of aldrin, fenvalerate, captan and diazinon were 0.00036, 0.0094, 0.5473 and 2.4186 ppm respectively. These values were lower than those obtained for an exposure of 96 hour. It shows the greater toxicity of the pesticides in a long-term exposure. The relative toxic potency of aldrin fenvalerate, captan and diazinon was in a ratio of 6807:241:4:1 respectively. Thus the chemically different groups of pesticides exhibit an order of toxicity as aldrin greater than fenvalerate greater than captan greater than diazinon for the freshwater catfish, Clarias batrachus. It infers that the catfish is most sensitive to aldrin and least sensitive to diazinon. The comparison of the sensitivity of various species tested against these pesticidal chemicals has also been done to review the available information.

Aldrin↗
PubMed1994

The effects of captan and captafol on different bacterial strains and on c-mitosis in V79 Chinese hamster fibroblasts.

The mutagenic activity of captan and captafol was tested using Ames strains and strains showing an SOS response. Captafol was mutagenic in S. typhimurium strain TA102 (uvr+) and captan in strain TA104 (uvrB). Both captan and captafol elicit damages in DNA recognized by correndonuclease II, as shown by the repair test, and induced the SOS repair system in E. coli PQ37 (uvrA) strain. Only captafol induced the SOS system in PQ35 (uvr+). The lack of induction of beta-galactosidase at nonpermissive temperature in E. coli MD332 (dnaCs uvrA) strain showed that neither chemical was able to produce DNA breaks. In V79 Chinese hamster fibroblasts higher induction of c-mitosis by captafol than by captan (22% and 15% over the control, respectively) was accompanied by a higher decrease in nonprotein sulfhydryl groups, mainly GSH (41% and 77%, respectively). The content of protein sulfhydryl groups was decreased by either fungicide to a similar extent.

Animals↗
PubMedDate not supplied

Development of enzyme immunoassay for captan and its degradation product tetrahydrophthalimide in foods.

A simple, sensitive, and precise enzyme-linked immunosorbent assay (ELISA) is described for the quantitation of captan as its degradation product tetrahydrophthalimide (THPI) in foods using polyclonal antibodies. Three hapten analogues of THPI with different alkyl spacer arm lengths were synthesized. Immunogens and coating proteins were prepared by coupling these haptens to human serum albumin and ovalbumin, respectively. A 5-carbon spacer arm appeared to be optimum for the production of antibodies. Heterologous coating proteins did not improve the sensitivity, but reduction of homologous coating protein concentration did improve the sensitivity, resulting in a concentration of test compound required to inhibit binding by 50% of 15.5 ng/mL. The antiserum is specific for captan, captafol, and THPI, but not other structurally related compounds. The minimum detection limit was 1 ng/mL; the linearity was 1-200 ng/mL. The overall recoveries of captan and THPI from 11 commodities spiked at 4 levels were 92 and 100%, respectively. The intra-assay and interassay coefficients of variation were 9.1 and 16.8% for apple blanks and 5.9 and 4.2% for apple spiked with 3 ppm THPI, respectively. The ELISA described is suitable for measuring captan and THPI at levels comparable to those typically found in fruit.

Animals↗
PubMed2006

Analytical method for assessing potential dermal exposure to captan, using whole body dosimetry, in small vegetable production units in Argentina.

An analytical method has been developed that can be used to determine the potential dermal exposure (PDE) of workers to the pesticide captan in small-scale horticultural production units. The methodology is based on the whole body dosimetry technique, using a cotton coverall and cotton gloves as sampling media, with protective clothing worn beneath the cotton media to protect the operator. The quantitative determination of captan was done by gas chromatography-electron capture detector (GC-ECD), with the analytical method validated by measuring limits of detection and quantification, linear ranges, sample recovery and precision. Special emphasis is placed on factors that affected the stability of captan during chromatographic determination. The data generated for potential dermal exposure are presented separately for mixing/loading and application activities. These data are compared with values obtained with visible tracers using a similar field technique. Margin of safety (MOS) values are also calculated for the agricultural procedures studied.

Agriculture↗
PubMed2004

Oxidative damages in isolated rat hepatocytes treated with the organochlorine fungicides captan, dichlofluanid and chlorothalonil.

The cytotoxicity and lipid peroxidative potency of the organochlorine fungicides captan (N-(trichloromethylthio)-4-cyclohexene-1,2-dicarboximide), dichlofluanid (N-dichlorofluoromethylthio-N'N'-dimethyl-N-phenylsulfamide) and chlorothalonil (2,4,5,6-tetrachloro-isophthalonitrile) were studied in isolated rat hepatocytes. These fungicides induced cytotoxicity and lipid peroxidation in a dose- and time-dependent manner. Considerable cytotoxicity and lipid peroxidation occurred after cells were treated with 25 microM and more of fungicide. The phosphatidylcholine hydroperoxide (PCOOH) content increased more than 300 times by captan (250-1000 microM), 400 times by dichlofluanid (250-1000 microM) and 20 times by chlorothalonil (25-1000 microM) after 1h of incubation, as compared with untreated control. Significant cytotoxicity occurred after 20 min (captan), 30 min (dichlofluanid) and 60 min (chlorothalonil) of incubation and lipid peroxidation was induced prior to cytotoxicity. The antioxidant alpha-tocopherol and cytochrome P450 inhibitor SKF-525A effectively prevented cytotoxicity and lipid peroxidation. Our results suggest that metabolites of these fungicides produced by the microsomal cytochrome P450 system, induced membrane phospholipid peroxidation that caused cytotoxicity.

Aniline Compounds↗