首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 421 毫秒
1.
1-(4′-Ethylphenoxy)-3,7-dimethyl-7-methoxy or ethoxy-trans-2-octene (the ethyl-methoxide and ethyl-ethoxide) are more stable in some biological systems and less stable in others than 1-(4′-ethylphenoxy)-3,7-dimethyl-6,7-epoxy-trans-2-octene (the ethyl-epoxide). In housefly adults and mealworm pupae the persistence increases in the order of the ethyl-epoxide, -methoxide and -ethoxide but with adult stable flies the epoxide is of intermediate stability. The alkoxides are metabolized in living insects and microsomal oxidase systems of houseflies and mouse liver mainly by O-dealkylation, at a higher rate for the methoxide than the ethoxide, but benzylic oxidation of the ethyl group also occurs and is more important in the degradation of the ethyl-epoxide than the ethyl-alkoxides. The photostability on silica gel is slightly better for the ethyl-ethoxide than the -methoxide or -epoxide.  相似文献   

2.
Five juvenile hormone analogues (JHAs) were tested by topical application to prepupae of a susceptible (S) and 8 insecticide-resistant (R) strains of the housefly. Activity was measured by the inability to completely emerge from the puparium. Aitosid (isopropyl 11-methoxy-3,7,1l-trimethyldodeca-2,4-dienoate) was the most active compound against the S strain (ED50 0.0033 μg/prepupa) followed by Ro 7-9767 [6,7-epoxy-3,7-diethyl-(3,4-(methylenedioxy)phenoxy)-2-cis/trans-octene], R-20458 [trans l-(4-ethylphenoxy)-6,7-epoxy-3,7-dimethyl-2-octene], sesamex, and NIA 23509 (10,11 -epoxy-N-ethyl-3,7,11-trimethyI-2,6-dodecadienamide). The R strains, designated by the name of the selecting insecticide, have been under pressure for over 10 years and are considered maximally resistant. The dimethoate-R and OMS-15-R (carbamate-resistant) strains exhibited high levels of cross resistance to all JHAs often exceeding 100x at the ED95 The fenthion-R strain showed high cross resistance toward all JHAs except Altosid, toward which it manifested an intermediate level (17.5x). The DDT/lindane-R demonstrated only negligible tolerance to Aitosid but an intermediate response to all the other JHAs. The OMS-12-R strain (phosphoramidothioate-R) exhibited intermediate to high levels of cross resistance toward all JHAs, whereas the parathion-R, Chlorthion-R and a multi-resistant field-collected strain showed only low to intermediate levels of cross resistance. On the basis of known degradative mechanisms of the OMS-15-R strain, mixed function oxidases apparently play an important role in deactivating JHAs.  相似文献   

3.
Binding data were gathered for the cecropia juvenile hormone (methyl(E, E cis)-10,11-epoxy-7-ethyl-3,11-dimethyl-2,6-tridecadienoate) and two of its analogs {isopropyl(2E, 4E)-11-methoxy-3,7,11-trimethyl-2,4-dodecadienoate; (E)-4-[(6,7-epoxy-3,7-dimethyl-2-nonenyl)-oxyl]-1,2-(methylenedioxy)benzene} with bovine serum albumin and rat hepatic microsomal cytochrome P450. The proteins were found to bind the juvenile hormone and juvenile hormone analogs with affinity constants ranging from 105 to 106M?1. Thermodynamic calculations suggest that the binding of all three compounds is electrostatic in nature and that the size of the ether and ester substituents can greatly influence the binding to proteins. The juvenile hormone and its analogs all formed spectrally apparent Type I complexes with oxidized cytochrome P450; one of the juvenile hormone analogs formed a spectrally observable product adduct with reduced cytochrome P450. The product complex may contribute many of the hormonal effects observed for this compound.  相似文献   

4.
1-(4′-Ethylphenoxy)-3,7-dimethyl-6,7-epoxy-trans-2-octene (the ethyl-epoxide), a potent insect morphogenetic agent, is converted to 6,7-diol and other derivatives in living cockroaches and mealworms. Enzyme preparations of these organisms, and of houseflies and several other insect species, also carry out these hydration and/or oxidation reactions. In addition, housefly microsomes epoxidize the ethyl-epoxide to a diepoxide. The diepoxide and diol are then converted by microsomes to at least six cyclic diols, probably via an epoxy-diol intermediate, the major ones being the cis- and trans-tetrahydrofurandiol derivatives. The metabolites formed by these reactions have little or no morphogenetic activity in Tenebrio assays. Attempts to find potent inhibitors for housefly epoxide hydratases were unsuccessful. The corresponding ethylphenyl geranyl ether is epoxidized by housefly microsomes, forming the more morphogenetically active ethyl-epoxide, but the major reaction is oxidation on the geranyl moiety to an unidentified olefinic carboxylic acid. The chemical modifications needed for improved stability and morphogenetic activity in this juvenoid series depend on the insect species and strain and the relative activities of their enzymes involved in various inactivation pathways.  相似文献   

5.
The compounds tested were isopropyl (±)-(E,E)-11 -methoxy-3,7,11-trimethyl-dodeca-2,4-dienoate (ZR 515) and 6,7-epoxy-3-ethyl-7-methylnonyl 4-ethylphenyl ether (R 20458) (two juvenile hormone mimics); 2,6-di-tert-butyl-4-(αα-dimethyl-benzyl)phenol (MON 0585) (which inhibits melanisation during pupation); diflubenzuron and 1-(4-chlorophenyl)-3-(2,6-dichlorobenzoyl)urea (PH 60:38) (which affect chitinisation during moulting); and (E)-oct-2-enoic acid and (E)-non-2-enoic acid (all of which are claimed to have “teratogenic” effects on insects). The relative potencies of these chemicals were assessed on eggs, larvae and pupae of several mosquito species. Their characteristic delayed harmful effects are described and related to various stages of metamorphosis.  相似文献   

6.
S,S-Di-isobutyl N ethylethylenebis(thiocarbamate) (R-31026) had a strong morphogenetic effect, acting by contact on the newly formed pupae of Tribolium confusum and Tribolium castaneum and thereby disrupting adult development. At a dietary concentration of 20 mg kg?1, 95% of pupae of T. confusum produced pupa-adult intermediates; T. castaneum pupae were affected to a smaller extent. Topical application with 0.002 μg per 0–24-h-old pupa of T. confusum resulted in the formation of 88% malformed intermediates. The larvae brought into contact with R-31026 were not affected and pupated normally, hence the compound differs in its activity from that of a typical juvenile hormone compound. On the other hand, the pupal morphogenetic activity of R-31026 resembles that of the typical juvenoid compound 3-[5-(4-ethylphenoxy)-3-methylpent-3-enyl]-2,2-dimethyloxirane (R-20458). The progeny of the emerging adults from pupae treated with either R-20458 or R-31026 were strongly affected. The effective dosages were far below those required for pupal morphogenetic activity. Biochemical studies showed an increase in the soluble protein fraction during the pupal stage after treatment with either R-31026 or R-20458 indicating disturbances in protein build-up. The bis(thiocarbamate) R-31026 has more favourable practical properties than R-20458 for controlling agricultural insects, because it does not prolong the larval feeding stage.  相似文献   

7.
The cecropia juvenile hormone and three of its analogs were compared as inducers of microsomal epoxidase, O-demethylase, and DDT dehydrochlorinase in the housefly, Musca domestica L. The compounds were the cecropia juvenile hormone, methoprene, hydroprene, 6,7-epoxy-3,7-diethyl-1-[3,4-(methylenedioxy)phenoxy]-2-octene, and piperonyl butoxide, a well known insecticide synergist. The compounds were administered by feeding at levels up to 1% in the diet for 3 days to 1-day-old female adults. Enzymes were then prepared and assayed for their activity using heptachlor, p-nitroanisole, and DDT as substrates.There was approximately a twofold increase in the microsomal oxidases and a 50% increase in DDT dehydrochlorinase after the treatment with the cecropia juvenile hormone, while methoprene had some activity as an inducer of the epoxidase (30% increase) but no activity in the case of the O-demethylase or the dehydrochlorinase. Hydroprene had no effect on any of the enzyme systems, while 6,7-epoxy-3,7-diethyl-1-[3,4-(methylenedioxy)phenoxy]-2-octene was an inhibitor of the two microsomal oxidases. The latter compound and piperonyl butoxide were strong inducers of DDT dehydrochlorinase, causing approximately twofold increases in the activity of this enzyme.There was evidence that the microsomal preparations were able to metabolize and inactivate methoprene and hydroprene, the action being oxidative in the case of methoprene and both oxidative and hydrolytic in the case of hydroprene. The oxidative metabolism of the two juvenile hormone analogs by the microsomal preparations was inducible by the cecropia juvenile hormone and by phenobarbital and dieldrin.  相似文献   

8.
Thirteen methylenedioxyphenyl (MDP) compounds, including commercial insecticide synergists and juvenile hormone analogs, were compared in their effect on detoxifying enzymes in the housefly (Musca domestica). Flies were fed a diet containing 1% of the compounds for 3 days. Enzymes were then assayed in vitro for their activity using aldrin and DDT as substrates. Piperonyl butoxide (PB), sesamex, propyl isome, sulfoxide, safrole, isosafrole, 6,7-epoxy-3,7-diethyl-1-[3-4(methylenedioxy) phenoxy]-2-octene (MDP-JH I) and 6,7-epoxy-3-methyl-7-ethyl-1-[3,4-(methylenedioxy) phenoxy]-2-octene (MDP-JH II) all caused a bimodal effect, inhibiting microsomal epoxidase and inducing DDT-dehydrochlorinase in the resistant Isolan-B strain. Two of these, PB and MDP-JH I, gave similar results with the susceptible strain, stw;w5 and two resistant strains, Fc-B and Orlando-DDT. However, o-safrole, piperonylic acid, piperonal, 3,4-methylenedioxybenzyl acetate and methyl-(3,4-methylenedioxy) benzoate had little or no effect on the enzyme systems studied. The standard susceptible strain (WHO-SRS) responded to these compounds very differently. Among those tested, piperonyl butoxide, sesamex, safrole, and isosafrole were inducers of microsomal epoxidase, a 4-fold increase occurring after treatment with sesamex. Only MDP-JH II showed a marked inhibition of the epoxidase. These treatments did not effect DDT-dehydrochlorinase activity in this strain.The enhancement of DDT-dehydrochlorinase activity by the MDP compounds is associated with an increased rate of DDT dehydrochlorination in vivo. The stimulatory effect could be blocked by treatment with actinomycin D or cycloheximide.  相似文献   

9.
T. Hoppe  M. Suchy 《EPPO Bulletin》1975,5(2):193-196
Two insect growth regulators of the juvenile hormone type, namely 6,7-epoxy-3-ethyl-(p-ethylphenoxy)-7-methylnonane, cis/trans mixture (compound A) and 6,7-epoxy-3,7-dimethyl-1-[3,4-(methylendioxy)-phenoxy]-2-nonene (compound B) have been tested for their persistence when treated on stored grain. The interim results of this trial showed inhibition of adult emergence of Ephestia kühniella Zell., Plodia interpunctella Hübn., Tribolium castaneum Herbst and Rhyzopertha dominica F. even 8 months after treatment. The gas-chromatography residue determination of compound A showed a reduction of 27 % of the original concentration within 8 months. No effect of compound A on the endosperm of the grain or taste of flour and bread could be found in the Bakery School in Lucerne.  相似文献   

10.
An investigation was made of the action of the juvenile hormone analogues (JHAs) methoprene (ZR-515) and 3-[5-(4-ethylphenoxy)-3-methylpent-3-enyl]-2, 2-dimethyloxirane (R-20458), and the insecticides chlorpyrifos and methomyl, when applied, separately or in combination, to the late insect stages of susceptible (S) and aminocarb-resistant (Rm) strains of Spodoptera littoralis Boisd. Sixth-instar larvae of the Rm strain showed detectable levels of cross-resistance to chlorpyrifos, methomyl and R-20458. However, cross-resistance to methoprene was less pronounced in the Rm strain. Treatment of the same instar with the ED50 of methoprene produced an appreciable level of sterility in the S strain, but this level decreased in the Rm strain. Similar treatment with R-20458 caused a lower level of sterility in the S strain and the Rm strain was less affected. In the S strain, the ED25 of either chlorpyrifos or methomyl when applied simultaneously with the ED25 of R-20458, produced an antagonistic effect and the Rm strain was more capable of resisting the joint action of these compounds. The treatment, ED25 chlorpyrifos + ED25 methoprene produced an additive effect on the S strain, while the Rm strain tolerated their combined action. Nevertheless, the treatment, ED25 methomyl + ED25 methoprene produced additive effects on both the S and Rm strains. The prepupae of the Rm strain tolerated the action of the insecticides methomyl and chlorpyrifos. A similar pattern of cross-resistance was also detected against the action of the two hormones at the ED25 level, while at the ED25 level, both the S and Rm strains were almost equally sensitive to the action of the two juvenoids. Chlorpyrifos-JHA combinations produced additive effects on prepupae of the S strain while the Rm strain completely resisted their joint action. Methomyl-JHA combinations produced high potentiation in the S strain, but the Rm strain remained insensitive to their joint action. Detectable levels of tolerance to the action of chlorpyrifos and methomyl at the ED25 and ED50 levels were indicated in 2-day-old pupae of the Rm strain. This was less evident in the case of JHAs, particularly methoprene, which was to some extent equally effective on both strains; the reproductive ability of the S and Rm strains was highly affected by this compound. The pupae of the Rm strains were equally as affected as those of the S strain by the combination ED25 chlorpyrifos+ ED25 R-20458. Nevertheless, the two strains showed antagonism to the action of chlorpyrifos with methoprene. A high level of potentiation was produced in the S strain to the combination of methomyl and R-20458 but the Rm strain was able to withstand their combined action. Of interest in this respect was the action of the combination of methomyl and methoprene, for which high levels of potentiation were detected in pupae of the S and Rm strains. This combination also Produced a high percentage of sterility in mated females of the Rm strain.  相似文献   

11.
Metabolism of [phenyl-14C] and [(2,5) pyrrolidine-14C] cisanilide was investigated in vitro with microsomal preparations from rat liver. Microsomal activity was associated with a mixed-function oxidase system that required O2 and NADPH and was inhibited by CO. Two major ether-soluble metabolites were isolated. They were identified as primary oxidation products: 2-hydroxy-2,5-dimethyl-1-pyrrolidinecarboxanilide (A) and 4′-hydroxy-2,5-dimethyl-1-pyrrolidinecarboxanilide (B). Minor ether-soluble metabolites were also isolated. Precursor product studies and qualitative thin layer chromatography analysis of [pyrrolidine-14C] and methylated [phenyl-14C] hydrolysis products suggested that these metabolites were secondary oxidation products formed from metabolites A or B. One of these metabolites appeared to be the dihydroxy product 2,4′-dihydroxy-2,5-dimethyl-1-pyrrolidinecarboxanilide. Crude microsomal preparations (postmitochondrial supernatant fractions) also formed small quantities (<10%) of polar metabolites. Enzyme hydrolysis with β-glucuronidase (Escherichia coli) indicated that approximately 50% of these metabolites were glucuronides. Similarities and differences in cisanilide oxidation in vivo in plants and in vitro with rat liver microsomal preparations were discussed.  相似文献   

12.
A comparison of different tissues indicated that fat bodies of both the cabbage looper (Trichoplusia ni Hubner) and the European corn borer (Ostrinia nubilalis Hubner) fifth-instar larvae possessed the greatest in vitro metabolic activity towards the anti-juvenile hormone, precocene II (6,7-dimethoxy-2,2-dimethylchromene). Although the metabolic pathway suggested possible involvement of an epoxide hydratase, addition of epoxide hydratase inhibitors to incubation mixtures containing fat body homogenates of either species did not result in an accumulation of intermediate metabolites. However, all of the compounds tested inhibited metabolism of precocene II by mixed-function oxidase(s) as follows: 1,1,1-trichloropropane-2,3-epoxide, 14%; 1,2,3,4-tetradydronapthalene-1,2-epoxide, 63 to 74%; 2,2-bis[4-(2,3-epoxypropyloxy)phenyl] propane, 39 to 63%; cyclohexane oxide, 23 to 63%; and 1-(4-propargylphenoxy)-2,3-epoxypropane, 85 to 92%.  相似文献   

13.
Pyridyl terpenoid ethers have outstanding juvenile hormone activity in Tenebrio molitor compared with their phenyl analogues (6,7-epoxy-3,7-dimethyloct-2-enyl 6-ethyl-3-pyridyl ether and 7-ethoxy-3,7-dimethyloct-2-enyl 6-ethyl-3-pyridyl ether are active at 100 pg/larva). The compounds were also active in Galteria mellonella and Culex pipiens.  相似文献   

14.
An epoxide hydrolase purified from midgut microsomes of southern armyworm (Spodoptera eridania) larvae exhibited high activity toward monosubstituted epoxides (1,2-epoxyoctane, 1,2-epoxypropane, and styrene oxide) and lower activity toward cis-1,2-disubstituted epoxides (cyclohexene oxide, and the cyclodienes HEOM, HCE, and chlordene epoxide). Trisubstituted epoxides (2-methyl-2,3-epoxyheptane and JH-1) as well as several cyclodiene insecticides (dieldrin, endrin, endo-epoxyaldrin, and anti-heptachlor epoxide) were refractory to enzymatic attack. It is concluded that both lipophilic and steric factors dictate the substrate specificity of the enzyme. With cyclohexene oxide the enzyme yields the 1R, 2R enantiomer of the trans-diol. The purified enzyme is inhibited by several epoxides and mixed-function oxidase inhibitors and the potency of 3,3,3-trichloro-1,2-epoxypropane and sodium picrylsulfonate suggest the importance of electronic factors in the inhibitory mechanism. Studies with specific amino acid modifiers suggest the presence of an essential lysine or histidine residue at the active site and indicate that the enzyme lacks a metal ion requirement and an essential cysteine residue. The purified enzyme has a molecular weight of 46,000 daltons and amino acid analysis and immunochemical studies show it to be very similar to, but not identical with, the epoxide hydrolase from mammalian liver microsomes.  相似文献   

15.
Twenty-seven compounds were screened as potential inhibitors of juvenile hormone esterases. Of these compounds O-ethyl-S-phenyl phosphoramidothiolate provided the best inhibition for the cabbage looper, Trichoplusia ni (Hubner), and the yellow mealworm, Tenebrio molitor L., while the juvenile hormone esterases of the house fly, Musca domestica L., were best inhibited by a juvenoid carbamate (1-(m-phenoxy-N-ethyl carbamate)-3,7-dimethyl-7-methoxy-2E-octene). The inhibition patterns of T. ni and T. molitor are similar, while those of M. domestica are relatively different. Further studies on the juvenile hormone and α-napthyl acetate esterases of T. ni showed that they could be differentially inhibited. Diisopropyl phosphorofluoridate and an alkyl trifluoromethyl ketone selectively inhibit the hydrolysis of α-naphthyl acetate and juvenile hormone, respectively, while O-ethyl-S-phenyl phosporamidothiolate inhibits both enzymes. The juvenile hormone esterases of T. ni also appear to be unique enzymes that are selective for juvenile-hormone-like molecules. The in vivo inhibition of T. ni juvenile hormone esterases by O-ethyl-S-phenyl phosphoramidothiolate slows the in vivo hydrolysis of juvenile hormone and results in delayed pupation and malformed larvae that resemble larval-pupal intermediates. Thus, the esterases involved in juvenile hormone metabolism appear to be important in juvenile hormone regulation.  相似文献   

16.
The metabolism of 2-[methoxy(methylthio)phosphinylimino]-3-ethyl-5-methyl-1,3-oxazolidine (Stauffer R-16,661), a new experimental insecticide, was investigated in the cotton plant, houseflies, and in in vitro enzymatic and model oxidation systems. The principal metabolite isolated both in vivo and in vitro proved to be the 4-keto derivative of R-16,661. The structure of this metabolite was confirmed by PMR and mass spectral analysis. Toxicological examination showed that the 4-keto metabolite was approximately equal to R-16,661 in toxicity to the white mouse but was substantially less toxic to the housefly.  相似文献   

17.
The sex pheromone gland extracts ofSpodoptera littoralis (Boisd.) in Israel were reexamined by capillary gas chromatography and capillary gas chromatography combined with mass spectrometry. The following compounds were identified: (Z)-9-tetradecenyl acetate (46%), (Z,E)-9,11-tetradecadienyl acetate (33%), (Z,Z)-9,11-tetradecadienyl acetate (4%), (E)-11-tetradecadienyl acetate (9%), (Z)-11-tetradecenyl acetate (7%), and (Z,E)-9,12-tetradecadienyl acetate (0.5-1%). Field tests with various combinations of the major attractant (Z,E)-9,11-tetradecadienyl acetate and the minor components indicated that the best lure forS. littoralis in Israel is 2 mg (Z,E)-9,11-tetradecadienyl acetate containing 0.2-1% of (Z,E)9,12-tetradecadienyl acetate.  相似文献   

18.
  相似文献   

19.
Major methanol-soluble metabolites of cisanilide (cis-2,5-dimethyl-1-pyrrolidinecarboxanilide) were isolated from excised, pulse-treated carrot and cotton leaves. They were identified as O-glucoside conjugates of primary aryl and alkyl oxidation products, 2,5-dimethyl-1-pyrrolidine-4-hydroxycarboxanilide and 2,5-dimethyl-3-hydroxy-1-pyrrolidinecarboxanilide. Comparative studies with carrot and cotton cell cultures showed similar initial pathways of cisanilide metabolism. Time-course studies with [14C-pyrrolidine]- and [14C-phenyl]cisanilide showed little, if any, cleavage of the herbicide molecule in either excised leaves or cell cultures. Quantitative differences in the metabolism of cisanilide by cell cultures and excised leaves included; a reduced capacity of cell cultures to form secondary glycoside conjugates and an increased ability of cell cultures to form methanol-insoluble residues.  相似文献   

20.
The photodegradation of diniconazole-M [(E)-(R)-1-(2,4-dichlorophenyl)-4,4-dimethyl-2-(1,2,4-triazol-1-yl)-1-pentene-3-ol] was studied as thin film on glass surface under sunlight. Photoproducts were separated and identified by NMR, IR, UV and mass spectroscopy. They were characterised as the (Z)-isomer of diniconazole-M, a cyclic alcohol and its corresponding ketone and an isoquinoline derivative. © 1997 SCI.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号