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1.
Enzymatically isolated leaf cells from navy beans (Phaseolus vulgaris L., cv. “Tuscola”) were used to study the effect of buthidazole (3-[5-(1,1-dimethylethyl)-1,3,4-thiadiazol-2-yl]-4-hydroxy-1-methyl-2-imidazolidinone) and tebuthiuron (N-[5-(1,1-dimethylethyl)-1,3,4-thiadiazol-2-yl]-N,N′-dimethylurea) on photosynthesis, protein, ribonucleic acid (RNA), and lipid synthesis. The incorporation of NaH14CO3, [14C]leucine, [14C]uracil, and [14C]acetic acid as substrates for the respective metabolic process was measured. Time-course and concentration studies included incubation periods of 30, 60, and 120 min and concentrations of 0.1, 1, 10, and 100 μM of both herbicides. Photosynthesis was very sensitive to both buthidazole and tebuthiuron and was inhibited in 30 min by 0.1 μM concentrations. RNA and lipid syntheses were inhibited 50 and 87%, respectively, by buthidazole and 42 and 64%, respectively, by tebuthiuron after 120 min at 100 μM concentration. Protein synthesis was not affected by any herbicide at any concentration or any exposure time period. The inhibitory effects of buthidazole and tebuthiuron on RNA and lipid syntheses may be involved in the ultimate herbicidal action of these herbicidal chemicals. 相似文献
2.
The effects of the herbicides hexazinone [3-cyclohexyl-6-(dimethylamino)-1-methyl-1,3,5-triazine-2,4(1H,3H)-dione] and chlorsulfuron (2-chloro-N-[(4-methoxy-6-methyl-1,3,5-triazin-2-yl)aminocarbonyl]benzenesulfonamide) on the metabolism of enzymatically isolated leaf cells from soybean [Glycine max (L.) Merr., cv. ‘Essex’] were examined. Photosynthesis, protein, ribonucleic acid (RNA), and lipid syntheses were assayed by the incorporation of specific radioactive substrates into the isolated soybean leaf cells. These specific substrates were NaH14CO3, [14C]leucine, [14C]uracil, and [14C]acetate, respectively. Time-course and concentration studies included incubation periods of 30, 60, and 120 min and concentrations of 0.1, 1, 10, and 100 μM of both herbicides. Photosynthesis was the most sensitive and first metabolic process inhibited by hexazinone. RNA and lipid syntheses were also inhibited significantly by hexazinone whereas the effect of this herbicide on protein synthesis was less. The most sensitive and first metabolic process inhibited by chlorsulfuron was lipid synthesis. Photosynthesis, RNA, and protein syntheses were affected significantly only by the highest concentration of this herbicide and longest exposure. Although these two herbicides may exert their herbicidal action by affecting other plant metabolic processes not examined in this study, hexazinone appears to be a strong photosynthetic inhibitor, while the herbicidal action of chlorsulfuron appeared to be related to its effects on lipid synthesis. 相似文献
3.
The rapid effects of the herbicide EPTC (S-ethyl dipropylthiocarbamate) and the protectant DDCA (N,N-diallyl-2,2-dichloroacetamide) on [2-14C]acetate incorporation into lipids of maize cell cultures were studied in order to determine whether they act at similar sites of lipid synthesis. DDCA, at 0.05 mM and 0.1 mM, increased the incorporation of [2-14C]acetate into neutral lipids of a total lipid extract within 2 h. It had very little effect on the major polar lipid constituents. DDCA altered neither the distribution of label within the major lipid classes, nor turnover of the major lipids within 2 h. EPTC (0.1 mM) inhibited overall uptake of [2-14C]acetate into both neutral and polar lipids by about 30% after a 2-h incubation. The major polar lipid affected was an unidentified glycolipid. In addition to reducing the quantity of lipids synthesized, EPTC changed the lipid profile, altering the distribution of label, mainly within the neutral lipid fraction. A crude membrane fraction from maize cells contained both polar lipids and some neutral lipids. DDCA stimulated [2-14C]acetate incorporation into different lipid species. EPTC inhibited incorporation of [2-14C]acetate into both neutral and polar membrane lipids but altered significantly only its distribution into neutral lipids. DDCA (0.1 mM) given together with EPTC (0.2 mM) partially counteracted the effect of EPTC within the neutral lipid fraction. It is suggested that DDCA has a rapid effect on lipid synthesis, but it is probably not sufficient to account for the entire mode of action of the protectant. 相似文献
4.
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
5.
The absorption, translocation and metabolism of the selective pre- or early post- emergence herbicide epronaz (N-ethyl-N-propyl-3-propylsulphonyl-1,2,4-triazole-1-carboxamide) were investigated using selected crop and weed species. The pattern of tolerance to epronaz of both germinating seeds and 10-day-old plants grown in nutrient solution, was found to be soybean (Glycine max L.) > maize (Zea mays L.) > cotton (Gossypium hirsutum L.) > rice (Oryza sativa L.) > barnyard grass [Echinochloa crus-galli (L.) Beauv.]. In all species, absorption and translocation of 14C from a nutrient solution containing [14C]epronaz (0.02 μCi ml?1) increased with time. Autoradiographic and liquid scintillation analysis indicated the presence of radioactivity in the apical regions of all species after 4 h. Interspecies variation in uptake and distribution did not appear to be a major factor explaining selectivity, although the resistance of cotton may be partly due to compartmentalisation of 14C in the lysigenous glands in stem and leaves. Analysis of extracts from plants treated with [14C]epronaz indicated the presence of epronaz, its major degradation product [3-propylsulphonyl-l,2,4-triazole (BTS 28 768)] and certain unknown radio-labelled compounds. The major metabolite (Unknown I) was believed to be a conjugate of certain plant components with either epronaz or BTS 28 768. The rate of formation of Unknown I corresponded to the relative resistance and susceptibility to epronaz of soybean, rice and barnyardgrass. The level of the herbicide remained much higher in cotton than in the other species, possibly reflecting compartmentalisation and inactivation of epronaz in the lysigenous glands. For maize, high levels of uptake, exudation and degradation in the nutrient solution were recorded. 相似文献
6.
Thomas Müller Peter Thanei Wolfgang Mücke Hans-Peter Kriemler Tammo Winkler 《Pest management science》1999,55(5):594-596
The metabolism of cyprodinil, a novel broad-spectrum fungicide, was investigated in rats. After single oral administration of 0.5 or 100 mg kg−1 body weight, [phenyl-U-14C]cyprodinil was rapidly eliminated, principally in the urine. The metabolite pattern in urine exhibited a significant sex-related difference with respect to the major metabolite. Males and females both produced a dihydroxy metabolite, N-4-(hydroxyphenyl)-4-cyclopropyl-5-hydroxy-6-methylpyrimidin-2-ylamine. Female rats conjugated this metabolite with sulfate exclusively at the 5-hydroxypyrimidinyl moiety, while males formed equal amounts of the monosulfate and a disulfate conjugate. The sex dimorphism in the conjugation reaction indicates the involvement of a sex-specific sulfotransferase that catalyzed the transfer of the second sulfate group. 相似文献
7.
The bacterium Azospirillum lipoferum is able to survive in high concen-trations of the organochlorine acaricide dicofol [1,1-bis-(4-chlorophenyl)-2,2,2-trichloroethanol]. It accumulates this chemical in the cell envelope where it is protected against hydrolysis. We investigated the nature of cell envelope molecules with which [14C]dicofol is associated; no indication of [14C]dicofol–saccharide bonds was found. We concluded that about 80% of the total [14C]dicofol found in the cells was associated with lipids and the remaining 20% with proteins. Electrophoresis did not indicate any correlation of a specific protein band with [14C]dicofol radioactivity peaks. After Folch partition, [14C]dicofol distribution in TLC analysis showed 60% of [14C]dicofol–lipid bonds related to neutral lipids, 20% to phospholipids and the remaining 20% of the bonds associated with other lipids. Experimental results suggested that [14C]dicofol associates mainly with membrane domains near proteins and that this association influences membrane fluidity as well as enzymatic activity. © 1998 SCI 相似文献
8.
[14C]Flamprop-methyl administered orally to rats (3-4 mg kg?1 body weight) was excreted mostly via the faeces (78.7 and 61.6% in males and females, respectively). Elimination was rapid and 90% of the dose of 14C was excreted in faeces and urine 0-48 h after dosing. The distribution of 14C between faeces and urine was different in males and females. No expired [14C]carbon dioxide was detected and less than 2% of the dose remained in the animals 4 days after dosing. The predominant metabolic pathway was hydrolysis of the ester bond to afford the carboxylic acid which was excreted unchanged and as its glucuronide conjugate. Aromatic hydroxylation occurred at the para- and meta-positions of the N-benzoyl ring. N-(3)-Chloro- 4-fluorophenyl-N-(3,4-dihydroxybenzoyl)-DL -alaninate was also formed. This hydroxylated form of flamprop-methyl was partially O-methylated at the 3-hydroxy group. Flamprop-methyl was also metabolised and eliminated rapidly by dogs, mice and rabbits. The last of these three species afforded very little aromatic hydroxylation and also differed from the others in that the metabolites were eliminated mostly in the urine. Aromatic hydroxylation lay in the order: male rat = female rat > dog= mouse>rabbit (female). 相似文献
9.
Corn (Zea mays L. single cross hybrid Mv 620) was germinated in a petri dish with addition of carbonyl[14C]EPTC (S-ethyl-N,N-dipropylthiocarbamate). The shoots and roots of 4-day-old seedlings were crushed and extracted in 80% methanol. On the chromatogram of the extract three radioactive peaks were found. The main peak was identified as S-(N,N-dipropylcarbamoyl)-glutathione. For the comparison of carbamoylating ability [14C]EPTC, [14C]EPTC-sulfoxide, and [14C]EPTC-sulfone were incubated with glutathione. Only EPTC-sulfone reacted in the 10-day incubation time. In aquatic solutions EPTC and EPTC-sulfoxide proved to be stable during the 10 days compared to EPTC-sulfone which quickly degraded, S-(N,N-Dipropylcarbamoyl)-glutathione was converted to S-(N,N-dipropylcarbamoyl)-cysteine in corn shoot homogenate. [14C]EPTC, [14C]EPTC-sulfoxide and [14C]EPTC-sulfone were added to corn shoot homogeneates and each of the three mixtures were analyzed by chromatography after 1 day incubation. EPTC was partly oxidized to EPTC-sulfoxide. EPTC-sulfoxide did not change and EPTC-sulfone produced similar metabolites as had been found in the germination experiment. 相似文献
10.
Seedlings of Solanum scabrum Mill. and Solanum ptycanthum Dun. were treated with [14C]ethalfluralin (N-ethyl-α,α,α-trifluoro-N-(methylallyl)-2,6-dinitro-p-toluidine) and [14C]trifluralin (α,α,α-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine) supplied in nutrient solution to determine the basis for differences in response by these two species to these two herbicides. Plants of S. scabrum absorbed more [14C]ethalfluralin and [14C]trifluralin than plants of S. ptycanthum. During the first 24 h, S. scabrum seedlings, but not S. ptycanthum seedlings absorbed more [14C]ethalfluralin than did plants treated with [14C]trifluralin. More [14C]ethalfluralin than [14C]trifluralin was found in the shoots of plants of both species. Seventy-two hours after treatment with [14C]herbicides, the conversion to water-soluble metabolites was greater for [14C]ethalfluralin than for [14C]trifluralin. In the shoots of plants from both species an average of nearly 55% of the 14C recovered was found in the water-soluble fraction following [14C]ethalfluralin treatment whereas an average of only 40% was found in the water-soluble fraction following [14C]trifluralin treatment. 相似文献
11.
The accumulation potential of six, structurally related, dinitroaniline herbicides was investigated in an aquatic ecosystem. The herbicides investigated were trifluralin (α,α,α-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine), profluralin [N-(cyclopropylmethyl)-α,α,α-trifluoro-2,6-dinitro-N-propyl-p-toluidine], dinitramine [N3,N3-diethyl-2,4-dinitro-6-(trifluoromethyl)-m-phenylenediamine], chlornidine [N,N-bis(2-chloroethyl)-2,6-dinitro-p-toluidine], fluchloralin [N-(2-chloroethyl)-2,6-dinitro-N-propyl-4-(trifluoromethyl)aniline], and butralin [4-(1,1-dimethylethyl)-N-(1-methylpropyl)-2,6-dinitrobenzenamine]. The herbicide (0.1 mg) plus 1 μCi of 14C-labeled herbicide was adsorbed on 100 g of soil (1 ppm), added to individual aquariums, and flooded with 4 liters of water. Algae, snails, and daphnia were added, and 14C in water was monitored for 30 days. Fish were added on Day 30, and all components were harvested 3 days later. Bioaccumulation ratios (concentration in organism/concentration in water) for fish depended on the amount of their exposure to sunlight: Aquariums held in the dark had higher ratios for fish (235–755) than did those exposed to sunlight (32–83). Bioaccumulation ratios in the dark for fish based on 14C from bound soil residues of butralin and profluralin were 76 and 119, respectively. Direct repeated applications of profluralin (without soil) at 4-day intervals resulted in a rapid increase, then a decrease in bioaccumulation ratios for Gambusia, but a continuous increase for catfish. 相似文献
12.
Michel Couderchet Pierre F. Bocion Reynold Chollet Karl Seckinger Peter Bger 《Pest management science》1997,50(3):221-227
Due to the presence of an asymmetrically substituted C atom, dimethenamid [2-chloro-N-(2,4-dimethyl-3-thienyl)-N-(2-methoxy-1-methylethyl)acetamide], a recently introduced N-thienyl chloroacetamide herbicide, exists as two stereoisomers (S and R) having differing herbicidal activities as demonstrated with a selection of weeds and Lemna minor. The activity of the two isomers was investigated in greater detail with the green alga Scenedesmus acutus and compared to that of alachlor [2-chloro-N-(2,6-diethylphenyl)-N-(methoxymethyl)acetamide]. As with alachlor, the S isomer (5 μM ) strongly inhibited algal growth and fatty acid desaturation while the R isomer had no effect. In short-term experiments (up to 5·5 h), the S isomer and alachlor (100 μM ) inhibited [14C]acetate uptake and its incorporation into fatty acids in the same manner, while the R isomer did not. Incorporation of [14C]acetate into a non-lipid fraction of the algae was strongly inhibited by alachlor and the S isomer (100 μM ) and only slightly by the R isomer. A 50% inhibition of incorporation of [14C]oleic acid into the same non-lipid fraction was attained with less than 10-7 M of the S isomer while 10-5 M of the R form of dimethenamid achieved only a 40% inhibition. The same stereospecificity of the compound on growth, fatty acid desaturation, acetate uptake and oleic acid incorporation provides strong evidence that dimethenamid may act upon a primary, specific target in lipid metabolism. Furthermore, the comparable biological activities of dimethenamid and alachlor indicate that this target is common to both N-phenyl and N-thienyl chloroacetamide herbicides. © 1997 SCI. 相似文献
13.
Effects of the herbicide EL-107 (N-[3-(1-ethyl-1-methylpropyl)-5-isoxazolyl]-2,6-dimethoxy-benzamide) on the growth of dicotyledonous plants are described. The herbicide did not inhibit germination but reduced the growth of rape (Brassica napus L.) by half at 0.0057 mg l?1. The most characteristic symptom induced was a swelling of the apical regions, and histological observations of root tips of Polygonum persicaria and rape revealed a progressve disappearance of the meristematic zone, which was replaced by enlarged cells almost devoid of cytoplasm. Growth of cells of Acer pseudoplatanus L. and soybean (Glycine max L.) cultured in suspension was also inhibited by EL-107, which induced a characteristic change in the cell morphology to an enlarged, rounded shape. EL-107 apparently did not block cell division; at a high concentration it produced some inhibition of protein synthesis, but in Acer cells only. In both types of cell cultures it inhibited, to some extent, the incorporation of glucose into cell wall material. 相似文献
14.
D.S. Frear E.R. Mansager H.R. Swanson F.S. Tanaka 《Pesticide biochemistry and physiology》1983,19(3):270-281
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
15.
The metabolism of [14C]asulam (methyl 4-aminophenylsulphonylcarbamate), [14C] aminotriazole (1H-1,2,4-triazol-3-ylamine) and [14C]glyphosate (N-(phosphonomethyl)glycine) were assessed in Equisetum arvense L. (field horsetail). Following application of the test herbicides (4mg?0.3 °Ci herbicide/shoot) to the shoots of 2-year-old pot-grown plants, the total recovery of 14C-label after 1 week and 8 weeks was high for all three herbicides (>80-0% of applied radioactivity). Asulam was persistent (>69-7% of recovered radioactivity) in both shoots and rhizomes. Sulphanilamide, a hydrolysis product of asulam, accounted for the remainder of the recovered radioactivity. Aminotriazole showed evidence of conjugation in shoots and rhizomes. The principal 14C-labelled component in shoots was composed of high proportions of aminotriazole (>76-3%) together with the metabolites: X (ninhydrin positive), β-(3-amino-1,2,4-triazolyl-1-)α-alanine, Y (diazotization positive) and various unidentified compounds. Rhizomes generally contained lower proportions of intact aminotriazole (>59.4%) together with the metabolites X,Y and unidentified compounds. The proportion of aminotriazole did not decrease with time in shoots or rhizomes; however, the ratio of metabolite X: Y moved in favour of Y as the interval after treatment increased. Glyphosate was extensively metabolised in shoots and rhizomes to yield aminomethylphosphonic acid (AMPA) and various unidentified compounds. Differential metabolism appears to be one of the factors which may govern the persistence and toxicity of the test herbicides in E. arvense. 相似文献
16.
A rat, given a single oral dose of [14C] cymoxanil, 1-(2-cyano-2-methoxyimino-[2-14C]-acetyl)-3-ethylurea, eliminated 91% of the radioactivity within 72 h. The urine contained 71%, the faeces 11%, and the expired air about 7% of the radiolabel; no 14C residue was found in the internal organs. Greater than 70% of the radioactivity in the urine was identified. The major metabolite was characterised as glycine, both free and conjugated, as hippuric acid and phenylaceturic acid [N-(phenylacetyl)-glycine], and probably in the form of polypeptides of low molecular weight. The other metabolites identified included 2-cyano-2-methoxyiminoacetic acid, 2-cyano-2-hydroxyiminoacetic acid and 1-ethylimidazolidine-2, 4, 5-trione. The minor metabolites included succinic acid and 2-oxoglutaric acid which indicated reincorporation of metabolic 14C. Cymoxanil, as such, was not detected in the urine. 相似文献
17.
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
18.
The ability of flax and black nightshade to metabolize chlorsulfuron was studied to determine if metabolism contributes to tolerance and to identify any metabolites produced. Plant leaves were treated with [14C]chlorsulfuron for a 24-hr period. The metabolites were extracted, separated by HPLC, and characterized. Mass spectral analysis and independent synthesis confirmed a major metabolite (B-1) as 2-chloro-N-{[4-(hydroxymethyl)-6-methoxy-1,3,5-triazin-2-yl]amino-carbonyl}benzenesulfonamide. A second major metabolite (B) was determined to be a carbohydrate conjugate of B-1. Plants were more tolerant to B-1 applications than to chlorsulfuron. These results suggest that metabolism may be the basis of selectivity to chlorsulfuron for tolerant broadleaf plants as well as for grasses. 相似文献
19.
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
20.
When the petioles of detached tobacco leaves (10–17 cm2) were incubated in aqueous solutions containing [14C]metalaxyl, uptake of the fungicide was dependent on the temperature and photoperiod. Detached leaves took up 78% more [14C]metalaxyl at 26°C than at 16°C. The rate of uptake in the light at 21°C was linear, but after an additional 20h in the dark, there was only twice as much fungicide in the leaves. Different sized leaves contained the same amount of fungicide per cm2 area. Uptake by detached leaves of the 14C-labelled anilide lactones ofurace and RE-26940 [2-methoxy-N-(tetrahydro-2-oxo-3-thienyl)acet-2′,6′-xylidide] was similar to that of metalaxyl. At the concentration of metalaxyl (66 ng ml?1) that controlled blue mould (Peronospora tabacina) on detached tobacco leaves, the amount of fungicide in the leaves was found to be 7.25 ng. Autoradiography showed that the distribution of [14C]metalaxyl in detached leaves after incubation for 23h was uniform, although higher concentrations of the label were present in the smaller veins of the leaves. 相似文献