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1.
Penetration and metabolism of [14C]vernolate in soybean [Glycine max (L.) Merr. var Ransom] pods and seeds were measured 0, 1, 4, 24, 48, or 72 hr after treatment which occurred at 40 days after flowering. Total 14C recovery decreased ca. 50% within 4 hr and the loss of 14C was considered to be a measure of volatility. Total nonpolar extractants decreased in a logarithmic pattern which approached 10% of total 14C recovered within 24–48 hr. Total polar extractants increased in a logarithmic pattern to a maximum of 90% of total 14C recovered within 24 hr. Seed nonpolar extractants never exceeded 2% of the total 14C recovered while pod nonpolar extractants consisted of vernolate plus an unidentified component that did not thin-layer chromatograph (TLC) as the sulfone or sulfoxide. Pod polar extractants increased with time to ca. 75% of the total 14C recovered (24–48 hr) and decreased to ca. 58% at 72 hr after treatment. Seed polar extractants averaged ca. 10% of total 14C recovered for the first 48 hr after treatment and then increased to 30% of total 14C recovered. Thus, [14C]vernolate per se concentration decreased to <1% of applied material within 72 hr through volatilization and degradation of nonpolar extractants to polar products. Polar metabolites showed two major patterns of vernolate detoxification. One detoxification system produced 14C-metabolites whose Rf's were equivalent to that reported in corn (Zea mays L.) [J. P. Hubbell and J. E. Casida, [J. Agric. Food Chem. 25, 404 (1977)] and accounted for <30% of the pod polar extractants. A second detoxification system was most prevalent in soybean pod and seed tissues and resulted in very rapid modification of vernolate with an unidentified product that was 85% of the extracted 14C within 4 hr after treatment and which decreased in concentration with time. Therefore, unexplained vernolate detoxification system(s) exist in soybean pod and seed.  相似文献   

2.
Cell suspension cultures of wheat and soybean were incubated with [14C]-1,1,1-trichloro-2,2-bis-(4-chlorophenyl)ethane (DDT), [14C]-1,1-dichloro-2,2-bis-(4-chlorophenyl)ethene (DDE), and [14C]-2,2-bis-(4-chlorophenyl)acetic acid (DDA) under standardized conditions. Polar metabolites were formed in yields of 1–2.5% in the cases of DDT and DDE, and of 56% in the case of DDA. A nonpolar metabolite was only observed in the case of DDT in soybean. This metabolite was identified as DDE on the basis of cochromatography and mass spectroscopy. By the same methods DDA was identified as a major polar DDT metabolite of both soybean and wheat. The further conversion of DDA to hexose esters was demonstrated by chromatographic and mass spectroscopic comparison with synthetic DDA-β-d-glucopyranosyl tetraacetate. These studies suggest the metabolic sequence, DDT → DDA → DDA-hexose ester.  相似文献   

3.
Accelerated degradation of vernolate, EPTC and butylate but not of cycloate was detected in soils from three locations in Israel which were treated annually with vernolate. Repeated application of EPTC to soils with and without a history of vernolate application, under laboratory conditions, resulted in a progressive increase in its rate of dissipation with each application. Accelerated degradation of EPTC was also rapidly induced by mixing small amounts (5%) of soil with a history of vernolate treatment with soil that had never received vernolate. Liberation of 14CO2 from [14C]EPTC was more rapid in vernolate-treated soils than in untreated soils, indicating a development of microbial populations in soil capable of rapidly degrading the EPTC. Degradation of [14C]EPTC was faster in soil previously cropped with maize than in non-cropped soil, but slower in soils cropped with cotton or peanuts.  相似文献   

4.
Metabolism of the substituted diphenylether herbicide, acifluorfen [sodium 5-(2-chloro-4-trifluoromethylphenoxy)-2-nitrobenzoate], was studied in excised leaf tissues of soybean [Glycine max (L.) Merr. ‘Evans’]. Studies with [chlorophenyl-14C]- and [nitrophenyl-14C]acifluorfen showed that the diphenylether bond was rapidly cleaved. From 85 to 95% of the absorbed [14C]acifluorfen was metabolized in less than 24 hr. Major polar metabolites were isolated and purified by solvent partitioning, adsorption, thin layer, and high-performance liquid chromatography. The major [chlorophenyl-14C]-labeled metabolite was identified as a malonyl-β- -glucoside (I) of 2-chloro-4-trifluoromethylphenol. Major [nitrophenyl-14C]-labeled metabolites were identified as a homoglutathione conjugate [S-(3-carboxy-4-nitrophenyl) γ-glutamyl-cysteinyl-β-alanine] (II), and a cysteine conjugate [S-(3-carboxy-4-nitrophenyl)cysteine] (III).  相似文献   

5.
The mechanisms for the tolerance of purple nutsedge (Cyperus rotundus L.) and susceptibility of yellow nutsedge (Cyperus esculentus L.) to methazole [2-(3,4-dichlorophenyl)-4-methyl-1,2,4-oxadiazolidine-3,5-dione] were studied. Both species absorbed and translocated[14C]methazole and metabolites from nutrient solution; however, greater amounts of 14C per unit weight were detected in yellow than in purple nutsedge. Although intact plants and excised leaves of both species rapidly metabolized methazole to DCPMU [1-(3,4-dichlorophenyl)-3-methylurea], detoxification of DCPMU to DCPU [1-(3,4-dichlorophenyl) urea] occurred more slowly in yellow than in purple nutsedge. Compared to yellow nutsedge, a greater percentage of the radioactivity in purple nutsedge was recovered as polar products. Polar products were converted to the free forms of the parent herbicide and to phytotoxic DCPMU by proteolytic enzyme digestion. Based on the findings of this study, at least three mechanisms (differential absorption, metabolism, and formation of polar products) account for the differential tolerance of these two species to methazole.  相似文献   

6.
The microsome-NADPH system of mouse liver oxidizes each of benthiocarb, butylate, cycloate, EPTC, molinate, pebulate, and vernolate herbicide chemicals to the corresponding thiocarbamate sulfoxide which is then cleaved by the liver soluble-glutathione system. These sulfoxides are also detected as transient metabolites in the liver of mice injected with EPTC, molinate, pebulate, and vernolate but not with the other three thiocarbamates. Thiocarbamate sulfones are not detected as metabolites of the thiocarbamates. Studies in vivo and in vitro with [14C]EPTC and -pebulate or their corresponding sulfoxides and/or sulfones further indicate that sulfoxidation is the initial metabolic step in cleavage of the thiocarbamate ester group. Sulfoxidation appears to be a detoxification mechanism for thiocarbamate herbicides in mammals.  相似文献   

7.
Root-treated alfalfa absorbs, translocates, and metabolizes [phenyl-14C]isopropyl carbanilate ([14C]propham). After 7 days of root treatment, the distribution of radiolabel was 73% for shoots and 27% for roots. Shoots and roots were extracted and separated into the polar, nonpolar, and solid residual components using a mixture of chloroform, methanol and water. The insoluble residues accounted for approximately 40% of the 14C found in shoots and roots. The nonpolar fraction (6.1% of the radiolabel in shoots and roots) was not characterized, but was shown to be some component other than parent propham. Propham was not found in either shoots or roots. The polar metabolites were partly purified on Amberlite XAD-2. Cellulase-liberated aglycones were derivatized and separated by high-performance liquid and gas-liquid chromatography. The infrared, nuclear magnetic resonance, and mass spectral data showed that the polar metabolites of alfalfa shoots and roots were glycoside conjugates of isopropyl 2-hydroxycarbanilate (2-hydroxypropham) and isopropyl 4-hydroxycarbanilate (4-hydroxypropham). Conjugated 4-hydroxypropham accounted for 45.9% of the 14C in the shoots and 3.4% of the 14C in the roots. Conjugated 2-hydroxypropham accounted for 3.4% of the 14C in the shoots and 1.4% of the 14C in the roots.  相似文献   

8.
Rehmannia glutinosa (Gaertn.) Libosch. ex Fisch. & Mey. was very tolerant to paraquat (1,1′-dimethyl-4,4′-bipyridinium). The paraquat concentration required to reduce dry weight of R. glutinosa by 50% (GR50) was 24 mM , whereas a similar effect was obtained with 0·75 mM in Zea mays L. (maize, cv. Dekalb) and Glycine max (L.) Merr. (soybean, cv. Kwangkyo). When 1·5 mM paraquat in 10% aqueous extract of R. glutinosa was applied to maize and soybean, growth inhibition reached 24% and 7%, respectively, of the untreated control. Decreased activity of paraquat due to the extract also occurred in both leaf discs and chloroplasts of soybean. The total amount of [14C]paraquat absorbed into soybean leaves after 48 h was 34%, but it was reduced to 17% when the extract was added. Translocation of [14C]paraquat was also inhibited in the presence of the extract. In thin-layer chromatography (TLC) analysis using various solvent systems, Rf values of [14C]paraquat with the extract differed from those without the extract. The results suggested that the aqueous extract of R. glutinosa contained a substance which could nullify paraquat activity. © 1997 SCI.  相似文献   

9.
Metribuzin [4-amino-6-tert-butyl-3-(methylthio)-1,2,4-triazin-5(4H)-one] metabolism was studied in tomato (Lycopersicon esculentum Mill. “Sheyenne”). Pulse-treatment studies with seedlings and excised leaves showed that [5-14C]metribuzin was rapidly absorbed, translocated (acropetal), and metabolized to more polar products. Foliar tissues of 19-day-old seedlings metabolized 96% of the root-absorbed [14C]metribuzin in 120 hr. Excised mature leaves metabolized 85–90% of the petiole-absorbed [14C]metrubuzin in 48 hr. Polar metabolites were isolated by solvent partitioning, and purified by adsorption, thin-layer, and high-performance liquid chromatography. A minor intermediate metabolite (I) was identified as the polar β-d-(N-glucoside) conjugate of metribuzin. The biosynthesis of (I) was demonstrated with a partially purified UDP-glucose: metribuzin N-glucosyltransferase from tomato leaves. A possible correlation between foliar UDP-glucose: metribuzin N-glucosyltransferase activity levels and differences in the tolerance of selected tomato seedling cultivars to metribuzin was suggested. The major polar metabolite (II) was identified as the malonyl β-d-(N-glucoside) conjugate of metribuzin.  相似文献   

10.
Perfusion of 14C-(ring)-parathion or 14C-(ring)-paraoxon with blood through isolated, intact rat livers resulted in the rapid degradation of these insecticides. Degradation was negligible in the absence of rat liver (controls), thus demonstrating the capacity of the liver per se to effectively degrade these compounds. Of the total radiocarbon recovered after liver perfusion with [14C]parathion, 33 % could be attributed to unchanged [14C]parathion (similarly distributed between the liver and the blood) while 67.9 % was degraded to water soluble compounds and 2.5% was converted to organic soluble paraoxon and traces of p-nitrophenol. Nearly all of the [14C]paraoxon, however, was degraded by the intact rat liver, resulting in water soluble products that amounted to 98.5% of the total radiocarbon recovered. Unexplained losses of radiocarbon with the perfusion apparatus used were lower in the presence of rat liver which degraded the insecticides to more water soluble compounds. The water soluble degradation products produced from [14C]parathion and [14C]paraoxon were non-toxic to mosquito larvae (Aedes aegypti L.). These ring-labelled products were found to be conjugated p-nito-phenol. Nearly all of the water soluble radiocarbon was located in the perfused blood, while only small amounts (1.8 to 3.0% of recovered) were excreted via the bile or were associated with the liver tissue (1.3 to 1.8 % of recovered).  相似文献   

11.
This laboratory reported that isopropyl-3-chlorocarbanilate-phenyl-U-14C (chlorpropham-phenyl-14C) was absorbed, translocated, and metabolized by soybean plants. Both polar metabolites and insoluble residues were found in roots, whereas only polar metabolites were found in shoot tissues. In both roots and shoots the polar metabolites were shown to be the O-glucoside of isopropyl-2-hydroxy-5-chlorocarbanilate (2-hydroxy-chlorpropham). In shoot tissue there were other polar metabolites that were not identified. The experiments with soybeans have been repeated, but with new isolation and purification procedures. The plants were root treated with both chlorpropham-phenyl-14C and isopropyl-3-chlorocarbanilate-2-isopropyl-14C. The roots and shoots were extracted and separated into the polar, nonpolar, and insoluble metabolic components, using the Bligh-Dyer extraction method. The polar metabolites were separated by gel permeation chromatography. Further purification was accomplished on Amberlite XAD-2. The polar metabolites from the shoot and root tissues were hydrolyzed either by β-glucosidase or hesperidinase. The enzyme liberated aglycones were derivatized and separated by gas-liquid chromatography, and the components were characterized by mass spectrometry or NMR. The results of this study showed that the polar metabolites of soybean shoots were 2-hydroxy-chlorpropham and isopropyl-4-hydroxy-3-chlorocarbanilate (4-hydroxy-chlorpropham). These two hydroxy-chlorpropham metabolites were found in soybean shoots at a ratio of approximately 1:1. The only aglycone found in root tissue was 2-hydroxy-chlorpropham. Using the new procedures, no evidence was obtained for the presence of the unidentified polar metabolites that were previously observed in shoot tissues.  相似文献   

12.
A 140-day laboratory incubation, using surface soil from a long-term soybean tillage study, evaluated tillage influence on [14C]metribuzin degradation. Higher plant residue conditions in no-tillage (NT) soil inhibited metribuzin mineralization to [14C]carbon dioxide as compared to metribuzin degradation patterns observed in conventional tillage (CT) soil. At 140 days, relative abundance of extractable 14C components in NT included polar metabolites > metribuzin = deaminated metribuzin (DA) = deaminated diketometribuzin (DADK), while in CT, components included metribuzin > polar metabolites > DADK?DA. Conditions in NT apparently inhibited polar 14C degradation, and resulted in its accumulation, while in CT polar 14C degradation proceeded relatively rapidly. For both NT and CT, more 14 C was measured in an unextractable fraction than in any other fraction. A greater portion of the unextractable fraction in NT was associated with decomposed plant residue than in CT. Surface accumulation of crop residue, such as occurs under NT, provided a soil environment which altered metribuzin degradation patterns.  相似文献   

13.
Goldfish (Carassius auratus) exposed to 20 parts per billion [14C]photodieldrin in a static system absorbed 80% of the radioactivity within 20 hr. The absorbed radioactivity was eliminated slowly with a half-life of 3 weeks. Photodieldrin and a ketone derivative were the major form of the radiocarbon eliminated in water, accounting for, respectively, 59 and 10.4% of the eliminated radioactivity. The ketone derivative was characterized by cochromatography (thin-layer and gas chromatography, gc) and gc-mass spectrometry. Approximately, 15 other polar and nonpolar metabolites were detected in the aqueous medium. The radioactivity in the fish consisted of 13 metabolites along with photodieldrin. Photodieldrin and the ketone derivative were the most abundant residues in the fish, accounting for 77 and 5.4% of the radioactivity, respectively.  相似文献   

14.
Metribuzin [4-amino-6-tert-butyl-3(methylthio)-1,2,4-triazin-5(4H)-one] metabolism was studied in soybean [Glycine max (L.) Merr. Tracy]. Pulse treatment studies with seedlings and excised mature leaves showed that [5-14C]metribuzin was absorbed rapidly and translocated acropetally. In seedlings, >97% of the root-absorbed 14C was present in foliar tissues after 24 hr. In excised leaves, 50–60% of the absorbed 14C remained as metribuzin 48 hr after pulse treatment, 12–20% was present as polar metabolites, and 20–30% was present as an insoluble residue. Metabolites were isolated by solvent partitioning, and were purified by adsorption, ion-exchange, thin-layer, and high-performance liquid chromatography. The major metabolite (I) was identified as a homoglutathione conjugate, 4-amino-6-tert-butyl-3-S-(γ-glutamyl-cysteinyl-β-alanine)-1,2,4-triazin-5(4H)-one. Metabolite identification was confirmed by qualitative analysis of amino acid hydrolysis products, fast atom bombardment (FAB), and chemical ionization (CI) mass spectrometry, and by comparison with a reference glutathione conjugate synthesized in vitro with a hepatic microsomal oxidase system from rat. Minor metabolites were identified as an intermediate N-glucoside conjugate (II), a malonyl N-glucoside conjugate (III), and 4-malonylamido-6-tert-butyl-1,2,4-triazin-3,5(2H,4H)-dione (N-malonyl DK, IV) by CI and FAB mass spectrometry. Alternative pathways of metribuzin metabolism are proposed.  相似文献   

15.
Rats and chickens were each given a single oral dose (10 or 100 mg/kg body wt) of 1,1,1-trifluoro-N-[2-methyl-4-(phenylsulfonyl)phenyl-14C(U)]methanesulfonamide ([14C]perfluidone). Depending on the size of the dose, from 8.4 to 36.2% of the [14C] was eliminated in the urine and from 36.4 to 85.4% was eliminated in the feces within 48 hr after dosing. Less than 1% of the [14C] given to laying hens as [14C]perfluidone was present in the eggs produced during the first 96 hr after dosing. The percentage of the administered [14C] that remained in these animals (body with G.I. tract and contents removed) varied from 0.34 (96 hr after dosing) to 1.68% (48 hr after dosing). 14C-labeled compunds in the urine and feces from the rats and chickens were purified by solvent extraction, column chromatography, and gas-liquid chromatography, and then identified by infrared and mass spectrometry. The parent compound was the major 14C-labeled component in the urine and feces of both animals. 1,1,1-Trifluoro-N-[2-methyl-4-(3-hydroxyphenylsulfonyl)phenyl]methanesulfonamide was present in the feces of both animals. The proposed structures of other metabolites were 1,1,1-trifluoro-N-hydroxy-N-[2-methyl-4-(phenylsulfonyl)phenyl]methanesulfonamide (rat urine) and 1,1,1-trifluoro-N-{2-methyl-4-[(methylsulfonyl)-phenylsulfonyl]phenyl}methanesulfonamide (chicken urine).  相似文献   

16.
The exposure of bluegill fish to 50 parts per billion [14C]dieldrin in a static system resulted in the absorption of 73.00% of the radioactivity in 48 hr. Following transfer of the fish to clean water, only 16.20% of the absorbed radiolabel was eliminated in 23 days. Out of the 93.65% of the absorbed radioactivity recovered, 9 radioactive spots were isolated which included unchanged dieldrin (74.39%), pentachloroketone (8.17%), and aldrin-trans-diol (8.04%) as major metabolites.  相似文献   

17.
The metabolism of [14C]phenoxyacetic acid (POA) was studied in cell suspension culture of soybean (Glycine max). POA was metabolized to 4-HO-POA, 4-HO-POA glucoside and 4-HO-POA glycosidic ester. A large part of the 4-HO-POA glucoside and small amounts of the glycosidic ester were recovered in the medium. POA was also converted to non-extractable residues bound to cell walls. Sequential extraction of cell-wall polymers showed that non-extractable residues, partly identified with 4-HO-POA and POA, were mainly associated with hemicelluloses and lignin. Comparison of the metabolism of [carboxy-14C]- and [phenyl-14C]POA revealed some degradation of the POA side-chain, followed in all probability by the incorporation of the aromatic moiety into cell walls. However, the sturdiness of the resulting bonds prevented precise identification of these bound aromatic structures. In summary, the degradation of POA in soybean cell culture provided a good model to study the formation of non-extractable residues of pesticides. © 1999 Society of Chemical Industry  相似文献   

18.
When [14C]F3-fluorodifen (2,4′-dinitro-4-trifluoromethyl diphenylether), carbonyl-[14C]CDAA (N,N-diallyl-2-chloroacetamide), and carbonyl-14C-propachlor (2-chloro-N-isopropylacetanilide) were fed to rats, 57 to 86% of the 14C was excreted via the urine within 48 hr. Although very little radioactivity was excreted in the feces of CDAA-treated rats, 15–22% of the 14C was excreted in the feces of propachlor- of fluorodifentreated rats and an average of 8% of the 14C remained in these rats 48 hr after treatment. Oxidation of the 14C label to [14C]O2 was not a major process in the metabolism of these herbicides. The only major radioactive metabolite present in the 24-h urine of fluorodifen-treated rats, 2-nitro-4-trifluoromethylphenyl mercapturic acid, accounted for 41% of the administered dose of 14C. In the metabolism of CDAA, the corresponding mercapturic acid accounted for 76% of the dose; it was the only major metabolite present in the 24-h urine. In contrast, three major metabolites were detected in the 24-h urine of propachlortreated rats, and the mercapturic acid accounted for only 20% of the dose. The mercapturic acid of each herbicide was identified by mass spectrometry.  相似文献   

19.
Using radiotracer methodology and dissection techniques it was demonstrated that [14]chlorpyrifos and/or its 14C-labeled metabolite(s) concentrated mainly in the gut tissues and malpighian tubules of American cockroaches, Periplaneta americana (Linnaeus), following sorption from a treated surface. Significantly lower (P ≤ 0.10) amounts of 14C were present in testes samples and no radioactive material was detected in brain tissue. After 41.5–48 hr of exposure of adult male American cockroaches to sublethal concentrations of [14C]chlorpyrifos, radioactivity was detected in the hemolymph of all cockroaches tested. The hemolymph accounted for 30.83% of the total sorbed 14C. A parabiotic experiment confirmed translocation of chlorpyrifos and/or its 14C-labeled metabolite(s) in hemolymph.  相似文献   

20.
Buffers and leaf discs of mature tobacco (Nicotiana tabacum L.) were utilized to study [14C]-ethylene and 14CO2 evolution from radiolabeled ethephon, (2-chloroethyl)phosphonic acid. Metabolic fate of [14C]ethephon in leaf discs was investigated by use of thin-layer chromatography, high-voltage paper electrophoresis, autoradiography, and liquid scintillation spectroscopy. The evolution of labeled ethylene generally increased with increasing buffer pH, buffer volume, and dosage of [14C]ethephon. [14C]Ethylene was evolved, increasingly with time, from [14C]ethephon either added to the buffer or applied to leaf discs. The rate of [14C]ethylene evolution was maximum during the first day and leveled off on the fourth day. More than 50% of the total [14C]ethylene evolution over a 96-hr period was recovered during the first 24 hr after [14C]ethephon application. No 14CO2 was evolved when [14C]ethephon was degraded in the presence of buffer or leaf discs. Only ethephon itself, and no detectable metabolite thereof, was discovered in the methanolic extract of the leaf disc tissue. An insignificant amount of 14C activity (approximately 2% of the extracted 14C) was detected in the residue. By means of gas chromatography, it was confirmed that in buffers and tobacco leaf tissue ethephon breaks down to release ethylene but not CO2.  相似文献   

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