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PubMed2005

Molecular mechanisms underlying mancozeb-induced inhibition of TNF-alpha production.

Mancozeb, a polymeric complex of manganese ethylenebisdithiocarbamate with zinc salt, is widely used in agriculture as fungicide. Literature data indicate that ethylenebisdithiocarbamates (EBDTCs) may have immunomodulatory effects in humans. We have recently found in agricultural workers occupationally exposed to the fungicide mancozeb a statistically significant decrease in lipopolysaccharide (LPS)-induced tumor necrosis factor-alpha (TNF) production in leukocytes. TNF is an essential proinflammatory cytokine whose production is normally stimulated during an infection. The purpose of this work was to establish an in vitro model reflecting in vivo data and to characterize the molecular mechanism of action of mancozeb. The human promyelocytic cell line THP-1 was used as in vitro model to study the effects of mancozeb and its main metabolite ethylenthiourea (ETU) on LPS-induced TNF release. Mancozeb, but not ETU, at non-cytotoxic concentrations (1-100 microg/ml), induced a dose- and time-dependent inhibition of LPS-induced TNF release, reflecting in vivo data. The modulatory effect observed was not limited to mancozeb but also other EBDTCs, namely zineb and ziram, showed similar inhibitory effects. Mancozeb must be added before or simultaneously to LPS in order to observe the effect, indicating that it acts on early events triggered by LPS. It is known that nuclear factor-kappaB (NF-kappaB) tightly regulates TNF transcription. We could demonstrate that mancozeb, modulating LPS-induced reactive oxygen species generation, prevented IkappaB degradation and NF-kappaB nuclear translocation, which in turn resulted in decreased TNF production. To further understand the mechanism of the effect of mancozeb on TNF transcription, THP-1 cells were transfected with NF-kappaB promoter-luciferase construct, and the effect of mancozeb on luciferase activity was measured. Cells transfected with promoter constructs containing kappaB site showed decreased LPS-induced luciferase activity relative to control after mancozeb treatment, confirming NF-kappaB binding as an intracellular target of mancozeb. Overall, this study contributes to our understanding of the mechanism underlying mancozeb-induced immunotoxicity.

Biotransformation↗
PubMed2001

Effects of Acrobat MZ and Tattoo C on Japanese medaka (Oryzias latipes) development and adult male behavior.

Exposure of Japanese medaka (Oryzias latipes) embryos and adult males to sublethal concentrations of two commonly used fungicides, Acrobat MZ and Tattoo C, had varying effects on development and adult male behavior. During embryolarval assays, medaka exposed to Acrobat exhibited decreased heart rates throughout embryonic development and were smaller at hatching than controls. Differences in hatching size were not apparent with Tattoo although some decrease in heart rate was observed at higher concentrations. Tail lesions and abnormal spinal development was a problem common to embryos exposed to Acrobat. Neither time to hatch nor early growth was affected by exposure to either fungicide. Adult males that had been exposed to high concentrations of Acrobat or Tattoo over a 28-day period were less likely to approach females during behavioral trials. The absence of other behavioral effects, particularly those related to reproductive performance, may have been due to females being sexually unreceptive during behavioral trials. No other behavioral modifications were apparent for adult males exposed to either fungicide. Information about developmental and behavioral responses to sublethal concentrations of pesticides is important for establishing environmental guidelines concerning their use.

Abnormalities, Drug-Induced↗
PubMed2002

Ethylenethiourea in urine as an indicator of exposure to mancozeb in vineyard workers.

In the present study, the personal exposure to mancozeb and/or ethilenethiourea (ETU) in 13 Italian vineyard workers and in 13 subjects without occupational exposure to pesticides was investigated. With this aim, the level of ETU in urine and the dermal exposure to mancozeb were determined. Baseline urinary ETU results were lower than the analytical limit of detection for all controls (<0.5 microg/g creatinine) and for ten workers (median <0.5, range <0.5-3.4 microg/g creatinine). In workers, urinary ETU was significantly increased at the end of shift (2.5, <0.5-95.2 microg/g creatinine) compared with baseline levels. End-shift urinary ETU was higher in operators using open tractors (n=7) than in those using closed tractors (n=5) (16.2 vs. 2.4 microg/g creatinine), but the difference was not significant (P=0.073). End-shift urinary ETU was positively correlated with dermal exposure to mancozeb determined both over the clothes and on the skin (Spearman's rho=0.770 and 0.702, P=0.009 and 0.024, respectively). Wine consumption positively influenced the excretion of ETU.

Adult↗
PubMedDate not supplied

Effect of mancozeb on ovarian compensatory hypertrophy and biochemical constituents in hemicastrated albino rat.

Mancozeb a carbamate fungicide was administered orally at doses of 500, 600, 700, and 800 mg/kg/day to normal hemicastrated virgin rats for 15 consecutive days to examine the effect on ovarian hypertrophy. Sham-operated and hemicastrated control rats were administered a similar quantity of olive oil. The vaginal smear and body weight of the rats were recorded daily and rats were sacrificed on the Day 16. The ovary, uterus, kidney, adrenal, spleen, liver, lungs, heart, thymus, and thyroid were removed and weighed. The left ovary from each animal was serially sectioned and stained for histologic studies. The hemicastrated control rats revealed a significant increase in relative ovarian weight with 66.3% hypertrophy. Treatment with 700 and 800 mg/kg/day mancozeb revealed a decrease in ovarian hypertrophy with 28.2 and 22.8% hypertrophy, respectively. There was no significant change in the number of estrous cycles and duration of each phase of the estrous cycle with 500 mg/kg/day mancozeb. However, there was a decrease in the number of estrous cycles, duration of proestrus, estrus, and metestrus with concomitant significant increase in the duration of the diestrus phase with 600, 700, and 800 mg/kg/day mancozeb treatment. There was a significant decrease in the number of healthy follicles with concomitant increase in the number of atretic follicles at higher doses of mancozeb. There were no significant changes in the body and organ weight with 500, 600, 700, and 800 mg/kg/day of mancozeb. The levels of protein, glycogen, total lipid, phospholipid, and neutral lipid were elevated in the liver, uterus, and ovary after hemicastration. Protein, glycogen, total lipid, phospholipid, and neutral lipid were not significantly changed in the liver, uterus, and ovary after 500 mg/kg/day mancozeb. However, treatment with 600, 700, and 800 mg/kg/day mancozeb showed a significant decrease in the levels of protein, glycogen, total lipid, phospholipid, and neutral lipid in the liver, uterus, and ovary, with the exception of liver total lipid and uterine glycogen. In addition to the decrease in the compensatory ovarian hypertrophy, mancozeb treatment reduced the number of healthy follicles with a concomitant increase in the number of atretic follicles. This finding plus disruption of the estrous cycle may be due to a direct effect on the ovary or the hypothalamo-hypophysial-ovarian axis.

Animals↗
PubMed2001

Postharvest treatments for the reduction of mancozeb in fresh apples.

The objective of this study was to determine the effectiveness of chlorine, chlorine dioxide, ozone, and hydrogen peroxyacetic acid (HPA) treatments on the degradation of mancozeb and ethylenethiourea (ETU) in apples. This study was based on model experiments at neutral pH and temperature. Fresh apples were treated with two different levels of mancozeb (1 and 10 microg/mL). Several of the treatments were effective in reducing or removing mancozeb and ETU residues on spiked apples. Mancozeb residues decreased 56-99% with chlorine and 36-87% with chlorine dioxide treatments. ETU was completely degraded by 500 ppm of calcium hypochlorite and 10 ppm of chlorine dioxide at a 1 ppm spike level. However, at a 10 ppm spike level, the effectiveness of ETU degradation was lower than observed at 1 ppm level. Mancozeb residues decreased 56-97% with ozone treatment. At 1 and 3 ppm of ozone, no ETU residue was detected at 1 ppm of spiked mancozeb after both 3 and 30 min. HPA was also effective in degrading the mancozeb residues, with 44-99% reduction depending on treatment time and HPA concentrations. ETU was completely degraded at 500 ppm of HPA after 30 min of reaction time. These treatments indicated good potential for the removal of pesticide residues on fruit and in processed products.

Decontamination↗
PubMed2001

Ozone and hydrogen peroxyacetic acid treatment to reduce or remove EBDCs and ETU residues in a solution.

Laboratory studies were conducted in a model system to determine the effects of ozone (1 and 3 ppm) and hydrogen peroxyacetic acid (HPA) (5 and 50 ppm) at pH 4.6, 7.0, and 10.7 and at 10 and 21 degrees C on the degradation of mancozeb in solution over a 30 min period. All samples were analyzed for residues by GLC and HPLC. Ozonation and HPA treatment were effective in degrading mancozeb in solution. Rate of mancozeb degradation was dependent on pH, with the fastest rate at pH 7.0. Ethylenethiourea (ETU) residue concentrations in the mancozeb solutions were monitored over 60 min. Under controlled conditions, the ETU residue concentrations increased during the 15 min reaction time and then decreased for all three pH values. At 3 ppm of ozone treatment, no ETU residues were detected at all three pH ranges after 15 min of reaction time. Degradation of ETU by HPA was greatest at pH 4.6, and no ETU residues remained after 5 min at either 5 or 50 ppm. The results showed that ozone and HPA gave excellent degradation of pesticide residues depending on pH and temperature. These experiments indicated the potential for the removal of pesticide residues on fruit and in processed products.

Ethylenethiourea↗
PubMed2002

Chlorine and chlorine dioxide treatment to reduce or remove EBDCs and ETU residues in a solution.

Calcium hypochlorite (Ca(OCl)(2)) and chlorine dioxide (ClO(2)), common disinfecting and bleaching chemicals used in the food industry, are potent oxidizing agents. In this paper, the degradation effects of chlorine dioxide on mancozeb and ethylenethiourea (ETU) residues were investigated in a model system and compared with those of liquid chlorine, under various conditions such as differing concentration, pH, reaction time, and temperature. All samples were analyzed for residues by GLC and HPLC. Rate of mancozeb degradation was dependent on pH, with pH 4.6 being the most effective. Mancozeb residues decreased 40-100% with chlorine and chlorine dioxide treatments. ETU residue concentrations in mancozeb solutions were monitored over 60 min. Under controlled conditions, the ETU residue concentrations increased up to 15 min reaction time and then decreased in all three pH ranges. Treatment with both chlorine and chlorine dioxide at pH 4.6, yielded no ETU residues at both 10 and 21 degrees C. The results show that chlorine dioxide gives excellent degradation effects at lower concentrations than liquid chlorine.

Calcium Compounds↗
PubMed2003

Determination of degradation products and pathways of mancozeb and ethylenethiourea (ETU) in solutions due to ozone and chlorine dioxide treatments.

The objective of the present study was to determine the degradation products of mancozeb and ethylenethiourea (ETU) and elucidate the possible degradation pathways in solution as a result of chemical oxidation using ozone and chlorine dioxide. This study was developed in a solution at 100 ppm of mancozeb and ETU concentration over the course of 60 min. Two different oxidizing agents used in this study were (1) ozone at 3 ppm and (2) chlorine dioxide at 20 ppm. Ozone was continuously provided throughout the course of the reaction. Degradation products were detected with high-resolution GC-MS. The total analysis time was 4 min per sample combined with rapid GC separation and time-of-flight mass spectrometry (TOFMS). Hydrolysis of mancozeb led to m/z 144 ion fragmentation, which is 5-imidazoledithiocarboxylic acid, as a major degradation product. ETU showed M(+) 102, which corresponds to its mass, indicating this compound was stable in distilled water and did not undergo hydrolysis during 60 min. The average retention times of mancozeb and ETU were approximately 181-189 and 210-230 s, respectively. Ozonation of mancozeb produced ETU as a major product. Treatment of ETU with ozone produced several degradation compounds. From prolonged ozonation, the CS(2) or CS group was removed. Overall, several byproducts identified were M(+) 60, M(+) 84, M(+) 163, M(+) 117, and M(+) 267 by ozone and M(+) 117, M(+) 86, and M(+) 163 by chlorine dioxide treatment. Several of these have been reported, but others have never been reported previously.

Chlorine Compounds↗
PubMed1999

Improvement in the determination of mancozeb residues by the carbon disulfide evolution method using flow injection analysis.

The sample decomposition of the carbon disulfide evolution method for the determination of dithiocarbamate residues was carried out in a closed vial in the presence of hexane. The evolved carbon disulfide was extracted by the organic solvent and injected in a flow system for its quantification as copper complex. The conditions for batch decomposition, flow injection determination, and association of both were investigated with sodium diethyldithiocarbamate as model substance. An one-channel flow system was employed where the carrier stream was the ethanolic ethylenediamine/copper solution. The determination range was of 0. 01-1.26 microg of CS(2), with a relative standard deviation of 0.06% (n = 10), with a sample throughput of 45 samples/h. The association of the batch decomposition with the flow system was carried out with the fungicide mancozeb and was applied to the analysis of its residue in potato, lettuce, cucumber, and green bean crops. The approach allowed the analysis of 11 samples in triplicate in 2 h, with recoveries between 85% and 92% and relative standard deviation about 2%.

Carbon Disulfide↗
PubMed1998

Biochemical alterations in Bradyrhizobium sp USDA 3187 induced by the fungicide Mancozeb.

We have previously shown that fungicide Mancozeb causes a 50% decrease in Bradyhizobium sp USDA 3187 growth rate and affects the bacteria-root symbiotic interaction. In order to elucidate the fungicide toxicity mechanism we determined the effects of Mancozeb on cell chemical composition, glutathione (GSH) content (molecule involved in the detoxification process), glutathione S-transferase (GST) activity and on polyamine, exopolysaccharides, capsular polysaccharides and lipopolysaccharides. Mancozeb produced biochemical alterations in membrane composition, polysaccharides and polyamines. In spite of the increment of GSH content and GST activity, they are not enough to prevent the growth diminution.

Bradyrhizobium↗
PubMed2004

Side effects of mancozeb on Typhlodromus pyri (Acari: Phytoseiidae) in vineyards: results of multi-year field trials and a laboratory study.

The side effects of mancozeb on the predatory mite Typhlodromus pyri were studied in 4-year field trials on grapevine and in the laboratory. In the field, the effect of mancozeb varied according to previous mancozeb use. In vineyards where mancozeb had commonly been used over years, this fungicide is generally slightly toxic, in some cases moderately toxic and rarely toxic. In plots were mancozeb has never been used, its effect on T. pyri was more pronounced and varied from moderately toxic to toxic. Despite the toxicity of mancozeb, T. pyri populations have never been eradicated. Laboratory results obtained with the French CEB guideline no. 167 confirmed those of the 4-year field study: mancozeb was significantly more toxic to T. pyri populations collected in plots where it had rarely been used before the field experiment. In plots where mancozeb had been used for a long time, the susceptibility of T. pyri populations to this fungicide was reduced and female survival, fecundity but also viability of female progeny were less affected by mancozeb. Even though toxicity of mancozeb increased in controlled conditions, a significant correlation was established between field and laboratory results.

Animals↗