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Zhonghua Lao Dong Wei Sheng Zhi Ye Bing... Dec 2002In order to explore the pathway of dealkylation of pesticides other than cytochrome P450 monocoxygenases, lipoxygenase (LOX)-mediated demethylation of aminocarb and some...
OBJECTIVE
In order to explore the pathway of dealkylation of pesticides other than cytochrome P450 monocoxygenases, lipoxygenase (LOX)-mediated demethylation of aminocarb and some other pesticides were measured.
METHOD
Formaldehyde generated in the reaction was estimated by Nash reaction to express the rate of demethylation of pesticides mediated by soy lipoxygenase (SLO).
RESULTS
N-demethylation of aminocarb mediated by SLO was found to depend on the incubation time, concentration of the enzyme, concentration of aminocarb and hydrogen peroxide. Under optimal conditions, Vmax value of 18 nmol of formaldehyde.min-1.nmol-1 of lipoxygenase was observed. The reaction exhibited Km values of 3.4 mmol/L for aminocarb and 235 mumol/L for hydrogen peroxide. A strong inhibition of the reaction by nordihydroguaiaretic acid, gossypol, and phenidone clearly implicated the lipoxygenase involvement as the protein catalyst. A significant decline in the formaldehyde accumulation in the presence of either reduced glutathione or dithiothreitol suggested generation of a free radical species as an initial oxidation intermediate during the demethylation of aminocarb by SLO. The inhibition of formaldehyde generation by butylated hydroxyanisole(BHT) and butylated hydroxy toluene(BHA) further supported this contention. In addition to aminocarb, seven other pesticides were also found to undergo N-demethylation, albeit at relatively low rates.
CONCLUSION
Certain pesticides may oxidatively undergo dealkylation via the lipoxygenase pathway in animals and plants.
Topics: Butylated Hydroxyanisole; Butylated Hydroxytoluene; Dealkylation; Free Radicals; Lipoxygenase; Pesticides; Phenylcarbamates; Glycine max
PubMed: 14694585
DOI: No ID Found -
Pest Management Science Jun 2001Pesticides with N,N-dimethyl and thiomethyl moieties (aminocarb, methiocarb and fenthion) were irradiated under artificial light (lambda > 290 nm) in an amorphous wax...
Pesticides with N,N-dimethyl and thiomethyl moieties (aminocarb, methiocarb and fenthion) were irradiated under artificial light (lambda > 290 nm) in an amorphous wax phase from Persica laevis DC. The effect of the presence of the wax on the photolysis rate differed in the three pesticides, increasing it in aminocarb, having little effect in methiocarb and slowing it down in fenthion. The presence of the wax affected the qualitative photodegradation behaviour of all the pesticides. The data obtained were compared with those for pirimicarb, which had been studied earlier.
Topics: Carbamates; Citrus; Fenthion; Insecticides; Kinetics; Light; Methiocarb; Models, Biological; Phenylcarbamates; Photolysis; Waxes
PubMed: 11407028
DOI: 10.1002/ps.329 -
Placenta Sep 2000This study investigated the hypothesis that human term placental lipoxygenase (HTPLO) and soybean lipoxygenase (SLO) are capable of mediating N-demethylation of selected...
This study investigated the hypothesis that human term placental lipoxygenase (HTPLO) and soybean lipoxygenase (SLO) are capable of mediating N-demethylation of selected phenothiazines and insecticides in the presence of linoleic acid (LA). In addition to being LA dependent, the N-demethylation reaction mediated by HTPLO and SLO was limited by incubation time, pH of the medium, concentration of the enzyme and the substrate. Using Nash reagent to monitor formaldehyde production, the specific activity for LA-dependent N-demethylation of chlorpromazine, a model phenothiazine, was determined to be 1.7+/-0.3 nmoles/min/mg HTPLO. Besides chlorpromazine, N-demethylation of promazine, promethazine and trimeprazine was also observed. The insecticide, aminocarb, displayed a specific activity of 2.2+/-0.3 nmoles/min/mg HTPLO for N-demethylation. Other insecticides, namely chlordimeform, dicrotophos and zectran, were oxidized in a similar manner. As compared with HTPLO, the rates of N-demethylation of phenothiazines and insecticides mediated by SLO were higher. Classical inhibitors of lipoxygenase, as well as antioxidants and free radical scavengers, caused a dose-dependent reduction in the production of formaldehyde from chlorpromazine and aminocarb by HTPLO. These results clearly demonstrate the ability of polyunsaturated free fatty acids to support N-demethylation of xenobiotics via the lipoxygenase pathway.
Topics: Carbamates; Cations; Chlorpromazine; Female; Formaldehyde; Free Radicals; Humans; Hydrogen-Ion Concentration; Insecticides; Linoleic Acid; Lipoxygenase; Methylation; Phenothiazines; Phenylcarbamates; Placenta; Pregnancy; Substrate Specificity
PubMed: 10985967
DOI: 10.1053/plac.2000.0547 -
Electrophoresis Nov 1999A method for the simultaneous separation and determination of N-methylcarbamate pesticides and their hydrolytic metabolites by micellar electrokinetic chromatography...
Multi-residue analysis of N-methylcarbamate pesticides and their hydrolytic metabolites in environmental waters by use of solid-phase extraction and micellar electrokinetic chromatography.
A method for the simultaneous separation and determination of N-methylcarbamate pesticides and their hydrolytic metabolites by micellar electrokinetic chromatography (MEKC) was developed. A mixture of five pesticides (carbaryl, propuxur, carbofuran, aminocarb, and methiocarb) and their corresponding phenols was studied to optimize the separation of its components in terms of various electrophoretic parameters such as buffer type, pH and concentration, sodium dodecyl sulfate concentration, injection conditions, and applied voltage. Excellent separation of all ten analytes was achieved within about 20 min. The optimized method was used for determinations in environmental water samples. Sample volumes of 250 mL were first preconcentrated in the pesticides and metabolites by passage through a LiChrolut EN sorbent column and then further enriched by on-column stacking. Dynamic ranges of 40 ng/L - 6 microg/L, limits of detection at the nanogram-per-liter level, and relative standard deviations from 2.6 to 7.4% were obtained. The proposed method surpasses high-performance liquid chromatography (HPLC) in separation efficiency. In fact, it provides more expeditious separations and allows more flexible adjustment of the selectivity. Also, it enables the quantification for the analytes studied in this work with decreased limits of detection.
Topics: Carbamates; Chromatography, High Pressure Liquid; Chromatography, Micellar Electrokinetic Capillary; Hydrogen-Ion Concentration; Hydrolysis; Insecticides; Water Pollutants, Chemical
PubMed: 10608712
DOI: 10.1002/(SICI)1522-2683(19991101)20:17<3439::AID-ELPS3439>3.0.CO;2-3 -
Environmental Health Perspectives May 1999Historical aerial applications of the insecticide Matacil 1.8D provide an opportunity to look for potential effects of the endocrine disrupting compound 4-nonylphenol...
Historical aerial applications of the insecticide Matacil 1.8D provide an opportunity to look for potential effects of the endocrine disrupting compound 4-nonylphenol (4-NP) on Atlantic salmon (Salmo salar) populations. Matacil 1.8D contained the carbamate insecticide aminocarb, with 4-NP as primary solvent. Between 1975 and 1985 Matacil 1.8D was applied to forests in Atlantic Canada to control damage from the spruce budworm (Choristoneura fumiferana). After spraying, estimated concentrations of 4-NP in water fell within a range in which estrogenic effects might be anticipated. The spraying coincided with final stages of smolt development in salmon. Salmon catch data were evaluated considering effects on survival of the smolt stage. There was a significant negative relationship between the returns of salmon and the proportion of tributaries sprayed within the Restigouche River drainage basin in 1977. There was also a broader event of unusually heavy salmon smolt mortality in 1977, which contains a significant relationship indicating that where Matacil 1.8D spraying occurred, the smolt mortality increased. For 16 rivers exposed to spraying between 1973 and 1990, a significant proportion (p<0.005) of the lowest salmon catches coincided with Matacil 1.8D spraying. A decline coinciding with the use of Matacil 1.8D was also apparent in blueback herring (Alosa aestivalis) catches in New Brunswick. Because similar relationships were not evident for Matacil 1.8F or fenitrothion, neither of which were formulated with 4-NP, we hypothesize that the 4-NP in Matacil 1.8D was the causal agent. Concentrations of 4-NP described here are within current ranges encountered in industrial effluents and municipal sewage outfalls.
Topics: Animals; Carbamates; Endocrine System; Insecticides; Pesticide Residues; Phenylcarbamates; Salmo salar; Water Pollutants, Chemical
PubMed: 10210690
DOI: 10.1289/ehp.99107349 -
Talanta Aug 1996The potential of variable angle synchronous spectroscopy (VASS) for fluorescent mixtures resolution was assessed and compared with the rank annihilation method (RAM)....
The potential of variable angle synchronous spectroscopy (VASS) for fluorescent mixtures resolution was assessed and compared with the rank annihilation method (RAM). For this purpose, a set of excitation-emission matrices from three standard cyclodextrin fluorescence-enhanced solutions of the pesticides aminocarb, carbendazim and coumatetralyl and a mixture of them was obtained. Careful selection of the spectral routes to be scanned provides analyte signals that are free of interferences. Application of the rank annihilation method to excitation-emission matrices (EEMs) obtained by conventional scanning spectrofluorimetry gives quantitative results that show poor precision and accuracy when compared to those of VASS. The recoveries from ternary mixtures by VASS are within 99-104% and by RAM within 84-130%.
PubMed: 18966608
DOI: 10.1016/0039-9140(96)01887-5 -
Toxicology May 1995Aminocarb, a phenylsubstituted methylcarbamate pesticide (4-dimethylamino-3-methyl-N-carbamate; matacil), previously suspected of a relatively low immunotoxic potential,...
Aminocarb, a phenylsubstituted methylcarbamate pesticide (4-dimethylamino-3-methyl-N-carbamate; matacil), previously suspected of a relatively low immunotoxic potential, was administered by four different exposure routes to C57BL/6 mice. A single sublethal exposure by oral and dermal routes stimulated humoral immune response at a relatively low dose; 1/256 LD50 of aminocarb. Intraperitoneal (i.p.) injection decreased the humoral PFC response, whereas inhalation of aminocarb had no marked effect on peripheral immune status in exposed animals. Thus, i.p. exposure resulted in higher immunotoxicity over oral administration of aminocarb. Similarly, marked route-related exposure differences in immunomodulatory effects of aminocarb were noted for mitogenic stimulation of spleen lymphocytes and mixed lymphocyte response. Other indices, such as delayed type hypersensitivity (DTH) and production of interleukin-2 (IL-2) were unchanged. Interestingly, expression of major histocompatibility complex (MHC) class II by purified, lipopolysaccharide (LPS)-stimulated B cells increased equally after i.p. and oral exposures to aminocarb. Overall, a weak immunosuppressive potential of aminocarb was concluded, which was possibly due to indirect interaction of the pesticide with the immune system. However, aminocarb may represent an autoimmunity-inducing toxic.
Topics: Administration, Cutaneous; Administration, Inhalation; Administration, Oral; Analysis of Variance; Animals; Antibody-Producing Cells; B-Lymphocytes; Carbamates; Female; Flow Cytometry; Hypersensitivity, Delayed; Immunity; Injections, Intraperitoneal; Insecticides; Interleukin-2; Lymphocyte Culture Test, Mixed; Mice; Mice, Inbred C57BL; Mitosis; Phenylcarbamates
PubMed: 7761998
DOI: 10.1016/0300-483x(94)03012-q -
Ecotoxicology and Environmental Safety Feb 1991Synchronous cultures of Chlamydomonas segnis Ettl. were treated with aminocarb (0.5, 5.0, 10.0, or 50.0 micrograms ml-1) at each specific phase of the cell cycle,...
Synchronous cultures of Chlamydomonas segnis Ettl. were treated with aminocarb (0.5, 5.0, 10.0, or 50.0 micrograms ml-1) at each specific phase of the cell cycle, namely, G1, S, G2, and M phases. The subsequent effects of some macromolecular products were assayed at the end of the M phase. Aminocarb treatments of 0.5 microgram ml-1 were at the no effects level on the parameters monitored. However, the higher concentrations of aminocarb tested, namely, 5, 10, and 50 micrograms ml-1, dramatically affected not only macromolecular syntheses but also some cell cycle events. Algistatic and algicidal effects were obtained with some treatments.
Topics: Carbamates; Carbohydrates; Cell Cycle; Chlamydomonas; DNA; Insecticides; Phenylcarbamates; Plant Proteins; RNA
PubMed: 1711972
DOI: 10.1016/0147-6513(91)90004-9 -
Fundamental and Applied Toxicology :... Nov 1990Genotoxicity of eight topically applied compounds was determined using the bone marrow micronucleus (MN) test and hair follicle nuclear aberration (NA) assay in CD1... (Comparative Study)
Comparative Study
Genotoxicity of eight topically applied compounds was determined using the bone marrow micronucleus (MN) test and hair follicle nuclear aberration (NA) assay in CD1 mice. Twenty-four hours after a single treatment, cyclophosphamide (CY), applied at doses corresponding to 1/4, 1/8, 1/16, and 1/32 of the published dermal LD50, and N-methyl-N-nitrosourea (MNU), applied at 1/4, 1/8, and 1/16 of the published dermal LD50, were found to increase the incidence of NA in a dose-dependent manner. The frequency of MN was significantly increased only at the highest dose of CY. Using the same protocol, six pesticides applied in dimethyl sulfoxide (DMSO) at doses of 1/8, 1/16, and 1/32 of the dermal LD50 were investigated. Aminocarb and chlordane induced a dose-dependent increase in the frequency of NA, while there was an observed increase in NA incidence at only the highest doses of dichlorvos (DDVP), 4,4'-DDT (DDT), and 2,4-dichlorophenoxyacetic acid (2,4-D). No effect was observed with fenitrothion on nuclear aberrations in hair follicles. Except for the highest dose of chlordane, none of the pesticides tested positive in the bone marrow micronucleus test. Serum cholinesterase levels were reduced to 70 +/- 4.7% of the DMSO control level with DDVP, 57 +/- 8.2% with aminocarb, and 60.3 +/- 4.8% with fenitrothion, indicating some systemic activity with these topically applied agents. The data suggest that aminocarb, chlordane, DDVP, DDT, and 2,4-D are genotoxic as determined by the NA assay and that this assay may be more useful in detecting topically applied genotoxic agents than the more often used bone marrow micronucleus test.
Topics: 2,4-Dichlorophenoxyacetic Acid; Administration, Topical; Animals; Bone Marrow; Carbamates; Cholinesterases; Cyclophosphamide; Dichlorvos; Dimethyl Sulfoxide; Fenitrothion; Hair; Male; Methylnitrosourea; Mice; Micronucleus Tests; Mutagens; Pesticides; Phenylcarbamates
PubMed: 2086312
DOI: 10.1016/0272-0590(90)90183-k -
Biomedical and Environmental Sciences :... Jun 1990The management of insect epidemics in large tracts of forest is difficult given the climatic conditions encountered, the topography of the forested land, the nature of... (Review)
Review
The management of insect epidemics in large tracts of forest is difficult given the climatic conditions encountered, the topography of the forested land, the nature of the forest, the types of chemical and/or biological insecticides registered for use, and the technologies available for insecticide application. Since 1952, the province of New Brunswick, Canada, has been heavily involved in attempting to control an epidemic of the eastern spruce budworm (Choristoneura fumiferana. Clemens) that has ravaged the coniferous softwoods of eastern Canada and the United States. Of the available options, the provincial government chose to develop an aerial spraying program, eventually selecting two chemical insecticides (fenitrothion and aminocarb) and one biological control agent (Bacillus thuringiensis). Concerns about possible impacts on human health led to extensive studies of the toxicology of these insecticides, the technology of aerial spraying, the development of less hazardous formulations, and the quantitation of off-target drift of aerosolized insecticides. These studies culminated in improvements in pesticide application and the establishment of regulations on safety or buffer zones around human habitation for certain types of aircraft applying different formulations of the insecticides.
Topics: Animals; Carbamates; Environmental Health; Fenitrothion; Humans; Insect Control; Insecticides; New Brunswick; Phenylcarbamates; Trees
PubMed: 2099793
DOI: No ID Found