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1.
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   

2.
The absorption, distribution, and metabolic fate of [14C]ethephon in flue-cured tobacco (Nicotiana tabacum L.) was studied using autoradiography, thin-layer chromatography, high-voltage paper electrophoresis, and liquid scintillation spectrometry. Labeled ethephon penetrated mature leaf tissue easily and was translocated primarily in an acropetal direction. No 14C activity was detected in any other plant part except the treated leaf. The first day after treatment, most of the translocated 14C was detected in the midrib, and after 2 days radioactivity was noticed in veinal areas distal to the point of application. Four days later, however, 14C was detected in slight amounts only in the midrib, indicating that [14C]ethephon was rapidly degraded by the leaf tissue. Depending on leaf position on the stalk, as much as 92% of the radioactivity had disappeared from the leaf tissue during the first day after treatment, and as little as 5% of the applied radioactivity was recovered 4 days later. Methanol-extracted plant residues contained insignificant amounts of 14C. All of the 14C in methanol extracts was present in the form of a labeled compound with an Rf value corresponding to that of ethephon, indicating the absence of any detectable metabolites of the parent compound. Smoke analysis of cigarettes showed that more [14C]ethylene than 14CO2 was recovered in the main stream, whereas the trend was reversed in the case of side stream smoke.  相似文献   

3.
The metabolism and conjugation of 3-phenoxybenzyl alcohol, a plant metabolite of permethrin and cypermethrin, have been examined in abscised cotton leaves. Mature cotton leaves were treated by petiole uptake of an aqueous solution of [α-14C]-3-phenoxybenzyl alcohol. Initially there was rapid formation of a compound identified as the glucosyl 3-phenoxybenzyl ether. Subsequently more polar compounds were formed and these were shown to be disaccharide conjugates of the alcohol with glucose and pentose sugars. The alcohol and its mono- and disaccharide conjugates were shown to undergo interconversion in cotton leaves, and evidence was obtained from experiments with [14C]glucose for the ready exchange of the glucose units on the conjugates with free glucose in the leaves. No larger carbohydrate conjugates of 3-phenoxybenzyl alcohol were detected under the conditions used.  相似文献   

4.
The metabolic fate of the 14C-labeled herbicide, 2-(3,4-dichlorophenyl)-4-methyl-1,2,4-oxadiazolidine-3,5-dione (bioxone), in cotton (Gossypium hirsutum L. “Acala 4-42-77”) was studied using thin-layer chromatography, autoradiography, and counting. Bioxone-14C was readily metabolized by cotton tissue to 1-(3,4-dichlorophenyl)-3-methylurea (DCPMU) and 1-(3,4-dichlorophenyl)urea (DCPU). Leaf discs metabolized bioxone-14C rapidly; 12 hr posttreatment, 65% of the 14C in methanol extracts was in forms other than intact herbicide. Excised leaves treated through the petiole with either heterocyclic ring-labeled or phenyl ring-labeled herbicide contained little bioxone-14C after 1 day; DCPMU was formed early then decreased with time. DCPU accounted for 55–70% of the 14C in excised leaves 3 days posttreatment. In intact plants treated via the roots, the herbicide was rapidly metabolized in the roots to DCPMU and DCPU; little or no intact herbicide was translocated to the leaves. Little radioactivity accumulated in the roots with time; the radioactivity in the leaves accounted for 80–90% of the methanol-soluble 14C 47 days posttreatment. Most of the 14C in the leaves was recovered as DCPU (50–60%) and unidentified polar metabolite(s) which remained at the origin of the thin-layer plates (30–40%). The percentage of radioactivity which remained in cotton residue after methanol extraction increased with time. Digestion of the plant residues with the proteolytic enzyme pronase indicated that some of the nonextractable 14C may be DCPMU and DCPU complexed with proteins. Similar metabolic patterns were noted after treatment with either heterocyclic ring-labeled or phenyl ring-labeled bioxone-14C. Generally, bioxone was metabolized to DCPMU which in turn was demethylated to DCPU. The herbicide and DCPMU were 20 times as toxic as DCPU to oat (Avena sativa L.), a susceptible species.  相似文献   

5.
Significant radioactivity detected in mature fruits, harvested from apple trees (Malus domestica Borkh., cv. ‘Golden Delicious’ and ‘Gloster’) that were soiltreated with [3,5-14C]amitrole, remained in the insoluble plant material after exhaustive extraction. These bound residues were solubilized with a mixture of pectinases and cellulases. Thus, separation and characterization of carbohydrates and xenobiotic moieties released during this procedure became possible. A part of the radiolabel was incorporated into natural products, indicating degradation of the applied amitrole and reassimilation of [14C] carbon dioxide.  相似文献   

6.
l-[U-14C]sucrose accumulation by phloem sieve tube members (PSTM) of wheat (Triticum aestivum L. ‘Holley’) and sorghum (Sorghum bicolor L. ‘G522 DR’) was inhibited by the nonpermeant sulfhydryl inhibitor p-chloromercuribenzenesulfonic acid (PCMBS), and this inhibition was reversed by the permeant sulfhydryl protectants dithiothreitol (DTT) and dithioerythritol (DTE). S-Ethyl dipropylthiocarbamate (EPTC) (≤0.1 mM) did not inhibit [14C]sucrose accumulation by wheat or sorghum PSTM. N-N-Diallyl-2-chloroacetamide (CDAA) (1 mM) inhibited [14C]sucrose accumulation by sorghum but not by wheat PSTM. The inhibition of [14C]sucrose accumulation in sorghum PSTM by the membrane permeant CDAA was reversed by DTT. Sorghum growth was inhibited by <1 μM CDAA. Membrane permeant 2-chloroallyl diethyldithiocarbamate (CDEC) (0.1 mM) inhibited [14C]sucrose accumulation by PSTM of sorghum but not wheat. The inhibition of sucrose accumulation in sorghum PSTM by 0.1 mM CDEC was reversed by DDT.  相似文献   

7.
In a lysimeter experiment, [3-14C]metamitron was sprayed in a preemergence treatment of sugar beets, corresponding to approx 4.9 kg metamitron (7 kg Goltix)/ha. After 6 months, the beets contained metamitron equivalents amounting to 0.1 mg/kg fresh wt, calculated on the basis of the specific radioactivity of the [3-14C]metamitron employed. Radioactivity was also detected in the pure sugar isolates. The 14C activity represented approx 0.2 mg metamitron equivalent/kg pure sugar. Since the specific radioactivities of the sugar fractions were too low to employ physicochemical methods, a microbial degradation was used to investigate whether the radiocarbon was incorporated in the sucrose molecule. Microorganisms (Proteus vulgaris) degraded [U-14C] sucrose and the sugar isolates at the same 14CO2 release rates under strictly controlled experimental conditions. This result indicates that about one fourth of the carbon from the C-3 position of the triazine ring of the metamitron, found in the sugar beets at harvest time, is partly being used as a substrate in the production of sucrose possibly via assimilation of mineralized 14CO2.  相似文献   

8.
Aqueous suspensions and oil emulsions of a commercial [14C]diflubenzuron (N-[[(4-chlorophenyl)amino]carbonyl]-2,6-difluorobenzamide) formulation (Dimilin W-25) remained on the leaf surface of greenhouse-treated plant tissues. Absorption, translocation, and metabolism of the [14C]diflubenzuron were not significant. Less than 0.05% of the applied 14C was found in newly developed plant tissues 28 days after spray treatment. [14C]Diflubenzuron was degraded in soil. After 91 days, biometer flask studies showed that 28% of the 14C incorporated into the soil as [14C]diflubenzuron was recovered as 14CO2. Major dichloromethane-soluble soil residues were identified as unreacted [14C]diflubenzuron and [14C]4-chlorophenylurea. A minor unknown degradation product cochromatographed with 2,6-difluorobenzoic acid. Insoluble 14C-residues increased with time and represented 67.8% of the residual 14C in the soil 89 days after treatment. Cotton plants grown for 89 days in [14C]diflubenzuron-treated soil contained only 3% of the 14C applied to the soil. Small quantities of acetonitrile-soluble [14C]4-chlorophenylurea were isolated from the foliar tissues. Root tissues contained small amounts of [14C]diflubenzuron and trace quantities of a minor 14C-product that chromotographed similarly to 2,6-difluorobenzoic acid. Most of the 14C in the plant tissues (84–93%) was associated with an insoluble residue fraction 89 days after treatment.  相似文献   

9.
Ring- and carboxyl-labelled [14C]2,4-D were incubated under laboratory conditions, at the 2 g/g level, in a heavy clay, sandy loam, and clay loam at 85% of field capacity and 20 1C. The soils were extracted at regular intervals for 35 days with aqaeous acidic acetonitrile, and analysed for [14C]2,4-D and possible radioactive degradation products. Following solvent extraction, a portion of the soil residues were combusted in oxygen to determine unextracted radioactivity as [14C]carbon dioxide. The remaining soil residues were then treated with aqueous sodium hydroxide, and the radioactivity associated with the fulvic and humic soil components determined. In all soils there was a rapid decrease in the amounts of extractable radioacitivity, with only 5% of that applied being recoverable after 35 days. All recoverable radioactivity was attributable to [14C]2,4-D, and no [14C]-containing degradation products were observed. This loss of extractable radioactivity was accompanied by an increase in non-extractable radioactivity. Approximately 15% of the applied radioactivity, derived from carboxyl-labelled [14C]2,4-D, and 30% from the ring-labelled [14C]2,4-D was associated with the soil in a non-extractable form, after 35 days of incubation. After 35 days, less than 5% of the radioactivity from the carboxyl-labelled herbicide, and less than 10% of the ringlabelled material, was associated with the fulvic components derived from the three soils. Less than 5% of the applied radioactivities were identifiable with any of the humic acid components. It was considered that during the incubation [14C]2,4-D did not become bound or conjugated to soil components, and that non-extractable radioactivity associated with the three soil types resulted from incorporation of radioactive degradation products, such as [14C]carbon dioxide, into soil organic matter.  相似文献   

10.
The absorption, translocation, and metabolism of two new, selectively toxic derivatives of carbofuran, 2,3-dihydro-2,2-dimethyl-7-benzofuranyl (di-n-butylaminosulfenyl)(methyl)carbamate and 2,3-dihydro-2,2-dimethyl-7-benzofuranyl (morpholinosulfenyl)(methyl)carbamate, were studied in cotton and corn plants 1, 3, 6, and 10 days following both stem injection and foliage treatment. Both carbamates were readily translocated to all plant parts following stem injection, but translocation following leaf application was restricted to within the leaf. In cotton plants, the dibutylaminosulfenyl derivative was easily hydrolyzed to form carbofuran which, in turn, was oxidized at the 3-position of the ring and the N-methyl group. These oxidized metabolites were then converted to plant conjugates. Major metabolites were carbofuran and 3-hydroxy-carbofuran followed by 3-keto-carbofuran phenol and N-hydroxymethyl-carbofuran. Five minor metabolites also were detected. In corn plants, the dibutylaminosulfenyl derivative gave the same metabolites, although the metabolism rate was significantly slower in corn relative to cotton. Overall, the results showed that there were no fundamental differences in the metabolism of the morpholinosulfenyl and dibutylaminosulfenyl derivatives. The stability of both carbamate derivatives in different solvent systems also was investigated.  相似文献   

11.
The degradation of bis(tri[1-14C]butyltin) oxide in two soils (1 mg tin kg?1) has been studied under laboratory conditions. Half of the applied compound disappeared from unsterilised silt loam and sandy loam in approximately 15 and 20 weeks, respectively; it disappeared also from the sterilised soils but to a lesser extent. The formation of small amounts of dibutyltin derivatives was established by thin-layer chromatography both in the unsterilised and sterile soils. The amount of unextractable radioactivity increased with time in the unsterilised and sterile soils. In the unsterilised soils 14C was released as [14C]carbon dioxide in amounts equivalent to 20% of the applied radioactivity for silt loam and 10.7% for sandy loam over a period of 42 weeks. Almost no [14C]carbon dioxide was released from the sterile soils, confirming microbial participation in the degradation of the compound in the unsterilised soils.  相似文献   

12.
The inhibition site of the phenylpyridazinone herbicide, norflurazon [SAN 9789, 4-chloro-5-(methylamino)-2-(3-trifluoromethylphenyl)-pyridazin-3(2H)one] was determined in a cell-free carotenogenic enzyme system from a mutant strain of Phycomyces blakesleeanus (Mucoraceae). The presence of norflurazon resulted in a reduced flow of radioactivity from [2-14C]mevalonic acid to phytoene (7,8,11,12,7′,8′,11′,12′-octahydro-ψ,ψ-carotene) and β-carotene (β,β-carotene), whereas an increased incorporation occurred in the C30 terpenoids, squalene, and ergosterol. Furthermore, radioactivity accumulated in geranylgeranyl pyrophosphate. Since no radioactivity was found in prephytoene pyrophosphate and the radioactivity in phytoene decreased upon addition of norflurazon, this herbicide exerts its primary inhibitory action on the reaction catalyzed by phytoene synthetase. The nonbleaching phenylpyridazinone BAS 13761 [4-chloro-5-methoxy-2-phenyl-pyridazin-3(2H)-one] did not show this effect. Other inhibitory sites of norflurazon, either on prenyl pyrophosphate synthetase or on the desaturation of phytoene, were excluded.  相似文献   

13.
[2-14C]Mevalonic acid incorporation into gibberellic acid precursors was measured in cell-free extracts from sorghum [Sorghum bicolor (L.) Moench var. G-522 DR] coleoptiles. 14C incorporation into ent-kaur-16-ene was inhibited ca. 90% by 10?7 to 10?4M metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl)acetamide]. [14C]Geranylgeraniol (GG) content increased. [14C]Farnesol content was not altered and [14C]geraniol content decreased. Total 14C incorporation was decreased by metolachlor. In the safener [α-(cyanomethoximino)benacetonitrile]-treated sorghum seed coleoptile cell-free system, total 14C incorporation increased, [14C]kaurene and relative kaurence content increased 4× up to 105M metolachlor, and [14C]farnesol, and [14C]GG contents increased while relative farnesol and relative GG contents were not influenced by metolachlor. Thus, the inhibition of kaurene synthesis by metolachlor was reversed by the safener. Since the biosynthetic processes are mevalonic acid → geraniol → farnesol → GG → copalylol → kaurene, these data corroborate a proposed gibberellic acid biosynthesis inhibition between GG and kaurene as well as a partial blockage between mevalonic acid and geraniol. Thus, a portion of metolachlor-induced growth inhibitions of sorghum could be explicable on the basis of gibberellic acid biosynthesis inhibitions.  相似文献   

14.
An enzymatic assay system has been developed to measure the relative potency of fungicides such as triadimefon, triarimol, triforine, and buthiobate as inhibitors of sterol 14-demethylation. The enzyme preparation used is the 8000g supernatant derived from a homogenate of an aerobically adapted, anaerobically grown, high sterol strain of Saccharomyces cerevisiae. After incubation of the enzyme with [2-14C]mevalonic acid and the fungicide the ratio, radioactivity in 4,4-dimethyl sterols/radioactivity in 4-demethyl sterols is determined. The higher this ratio is, the more efficient is the fungicide as an inhibitor of fungal sterol 14-demethylation. The ratio has been determined for a number of commercial fungicides and two series of triazole compounds. A similar assay system based on the 10,000g supernatant from a rat liver homogenate was also tested but gave an inaccurate assessment of the relative potency of fungicides as inhibitors of fungal sterol 14-demethylation.  相似文献   

15.
The experimental, aquatic herbicide fluridone (1-methyl-3-phenyl-5-[3-(trifluoromethyl)phenyl]-4(1H)-pyridinone) was degraded in two submersed soils and in the water above those soils to one acidic metabolite (identified as 1,4-dihydro-1-methyl-4-oxo-5-[3-(trifluoromethyl)phenyl]-3-pyridinecarboxylic acid by mass spectrometry). A sandy and a silt loam soil were treated with [14C]fluridone, immersed in water, and analyzed after 1, 3, 5, 7, 9, and 12 months. Seven to fifteen percent of the 14C applied to the soils was recovered in the water on each of the various collection dates. The acidic metabolite accounted for 86 to 93% of the radioactivity in the water fraction 7 months after treatment. The metabolite was absorbed strongly by both soils and comprised about 60% of the total 14C in each soil after 12 months. The remainder of the 14C in the soils after 12 months was either the parent compound (～30%) or an undefined insoluble residue (～10%).  相似文献   

16.
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   

17.
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   

18.
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   

19.
The uptake and translocation of [14C]asulam (methyl 4-aminophenyl-sulphonylcarbamate), [14C]aminotriazole (1-H-1,2,4-triazol-3-ylamine) and [14C]glyphosate (N-(phosphonomethyl)glycine) were assessed in Equisetum arvense L. (field horsetail), a weed of mainly horticultural situations. Under controlled-environment conditions, 21°C day/18°C night and 70% r. h., the test herbicides were applied to 2-month-old and 2-year-old plants. Seven days following the application of 0.07-0.09 °Ci (1.14mg) of the test herbicides to young E. arvense, the accumulation of 14C-label (as percentage of applied radioactivity) in the treated shoots, untreated apical and basal shoots was as follows: [14C]asulam, 13.2, 0.18 and 1.02%; [14C] aminotriazole, 67.2, 3.65 and 1-91%; [14C]glyphosate, 35.9, 0.06 and 0.11%. The equivalent mean values for the accumulation of 14C-label in 2-year-old E. arvense were [14C]asulam, 12.0, 1-15 and 1.74%; [14C]aminotriazole, 58.6, 9.44 and 4.12%; [14C]glyphosate, 33.1, 0.79 and 2.32%. In the latter experiment, test plants received 0.25-0.30 °Ci (4mg) of herbicide, they were assessed after a 14-day period and the experiment was carried out at 3-week intervals between 2 June and 25 August on outdoor-grown plants. Irrespective of test herbicide or time of application, very low levels of 14C-label accumulated in the rhizome system. Only 0.2% of the applied radioactivity was recovered in 2-year-old plants and 0.4% in 2-month-old plants. In the young plants [14C]asulam accumulated greater amounts and concentrations of 14C-label in the rhizome apices and nodes than [14C]aminotriazole or [14C]glyphosate treatments. Inadequate control of E. arvense under field conditions may be due to limited basipetal translocation and accumulation of the test herbicides in the rhizome apices and nodes.  相似文献   

20.
[14C]Buturon, a urea herbicide, was sprayed on soil and winter wheat as an aqueous formulation (2.98 kg/ha) under outdoor conditions. Three months after application, a total of 49.2% of the applied radiocarbon was recovered: 46.9% in the soil, 0.3% in the leaching water (depth > 50 cm), and 2.0% in the plants. Radioactive residues in the soil were distributed to a depth of 50 cm and decreased with increasing depth of the soil. An average of 47% of the radioactivity present in the soil could be extracted with cold chloroform; by this extraction method, the formation of artefacts was avoided. Between one and two thirds of the extracted radioactivity was unchanged buturon. In the soil extracts, the following eight conversion products were isolated and identified by combined gas chromatography/mass spectrometry: N-(p-chlorophenyl)-N-methyl-O-methyl carbamate; N-(p-chlorophenyl)-O-methyl carbamate; N-(p-chlorophenyl)-N′-methyl-N′-isobutenyl-urea; N-(p-chlorophenyl)-N′-methyl-urea, N-(p-chlorophenyl)-N′-methyl-N′-isobutenylol-urea; p-chloroaniline in “biologically bound” form; N-(p-chlorophenyl)-N′-methyl-N′-methoxyisobutenyl-urea; and N-(p-chlorophenyl)-N′-methyl-N′-ethoxyisobutenyl-urea. In the leaching water, which contained only 0.005–0.006 mg/liter of radioactive substances, the following three conversion products were isolated and identified by gas chromatography/mass spectrometry: p-chloroformanilide; N-(p-chlorophenyl)-N-methyl-O-methyl carbamate; and an N-hydroxyphenyl-N′-methyl-N′-isobutinyl-urea. The results are discussed in relation to the factors responsible for the formation of these products.  相似文献   

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