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1.
Applied topically to larvae of Rhodnius prolixus, Triatoma infestans, Triatoma Vitticeps, Panstrongylus herrera and Panstrongylus megistus a novel, synthetic, furan-containing anti-juvenile hormonal compound, 2-(2-ethoxyethoxy)ethyl furfuryl ether (EEFE) induced a variety of biological responses attributable to an enforced cessation of juvenile hormone secretion, including precocious metamorphosis into diminutive adultoids and retardation of molting. The highest percentage of precocious adultoids was obtained when EEFE was applied prior to feeding. In decreasing order of sensitivity to this anti-juvenile hormone (AJH) were T. infestans, R. prolixus, P. herrera, P. megistus and T. vitticeps. The ED50 of EEFE in R. prolixus compared well with that of the botanically derived AJH, precocene II, but T. infestans was significantly more sensitive to the furanyl antihormone than to precocene II. The significance of these findings is discussed in terms of the complexity of expression of the anti-juvenile hormonal activity during the post-embryonic development of triatomines.  相似文献   

2.
Juvenile hormone (JH) is an insect-specific hormone that regulates molting and metamorphosis. Hence, JH signaling inhibitors (JHSIs) and activators (JHSAs) can be used as effective insect growth regulators (IGRs) for pest management. In our previous study, we established a high-throughput screening (HTS) system for exploration of novel JHSIs and JHSAs using a Bombyx mori cell line (BmN_JF&AR cells) and succeeded in identifying novel JHSIs from a chemical library. Here, we searched for novel JHSAs using this system. The four-step HTS yielded 10 compounds as candidate JHSAs; some of these compounds showed novel basic structures, whereas the others were composed of a 4-phenoxyphenoxymethyl skeleton, the basic structure of several existing JH analogs (pyriproxyfen and fenoxycarb). Topical application of seven compounds to B. mori larvae significantly prolonged the larval period, suggesting that the identified JHSAs may be promising IGRs targeting the JH signaling pathway.  相似文献   

3.
Insect juvenile hormone (JH) mimics (JHMs) are known to have ovicidal effects if applied to adult females or eggs. Here, we examined the effects of exogenous JHMs on embryonic development of the bean bug, Riptortus pedestris. The expression profiles of JH early response genes and JH biosynthetic enzymes indicated that JH titer was low for the first 3 days of the egg stage and increased thereafter. Application of JH III skipped bisepoxide (JHSB3) or JHM on Day 0 eggs when JH titer was low caused reduced hatchability, and the embryos mainly arrested in mid- or late embryonic stage. Application of JHMs on Day 5 eggs also resulted in an arrest, but this was less effective compared with Day 0 treatment. Interestingly, ovicidal activity of synthetic JHMs was much lower than that of JHSB3. This study will contribute to developing novel insecticides that are selective among insect species.  相似文献   

4.
BACKGROUND: One of the most studied actions of juvenile hormone (JH) is its ability to modulate ecdysteroid signaling during insect development and metamorphosis. Previous studies in mosquitoes showed that 20‐hydroxyecdysone (20E) regulates vitellogenin synthesis. However, the action of JH and its mimics, e.g. methoprene, on female reproduction of mosquitoes remains unknown. RESULTS: Here, a major malaria vector, Anopheles gambiae Giles, was used as a model insect to study the action of methoprene on female reproduction. Ecdysteroid titers and expression profiles of ecdysone‐regulated genes were determined before and after a blood meal. An ecdysteroid peak was detected at 12 h post blood meal (PBM). The maximum expression of ecdysone‐regulated genes, such as ecdysone receptor (EcR), hormone receptor 3 (HR3) and vitellogenin (Vg) gene, coincided with the ecdysteroid peak. Interestingly, topical application of methoprene at 6 h PBM delayed ovarian development and egg maturation by suppressing the expression of ecdysone‐regulated genes in female mosquitoes. CONCLUSION: The data suggest that ecdysteroid titers are correlated with Vg synthesis, and methoprene affects vitellogenesis by modulating ecdysteroid action in A. gambiae. Copyright © 2010 Society of Chemical Industry  相似文献   

5.
New types of juvenogens, which are biochemically activated juvenoid esters, have been assayed for juvenile hormone activity in three species of insects. The hormonally active component, liberated from the juvenogen substrate by carboxylesterase enzymes within the insect's body, was a secondary juvenoid alcohol related to the well-known group of juvenile hormone analogs derived from 4-substituted (7-alkoxygeranyloxy)benzenes. Juvenogen esters obtained by acylation of this juvenoid alcohol with a homologous series of C2 to C18 straight-chain monocarboxylic acids retain the juvenile hormone activity of the parental alcohol. The corresponding formyl derivative, as a first member of the series, was inactive and the activity of esters with longer acyl radicals than C18 also successively diminished. Such a weak dependence for juvenile hormone activity on the size of the molecule has not previously been encountered in juvenoid esters which do not yield biologically active hydrolysis products. These findings favor an assumption that juvenogens may represent selective, nontoxic, hormonally acting pesticides whose physicochemical properties (volatility, lipophility, stability) can be adjusted to suit practical requirements by simple alterations of the biologically unimportant acyl component. Moreover, this can be done without affecting the species-specific properties in the juvenile hormone activity of the built-in juvenoid product.  相似文献   

6.
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   

7.
Seventeen substituted imidazoles were tested as inhibitors of juvenile hormone (JH) III synthesis by cockroach corpora allata in an in-vitro radio-chemical assay. Most of these 1,5-disubstituted imidazoles were highly potent, with IC50 values of less than 100nM. The compounds differed in their ability to cause an accumulation of the precursor methyl farnesoate in the glands. Four of the imidazoles were tested by topical application to previtellogenic adult females, and all caused a significant inhibition of JH synthesis and an accumulation of intraglandular methyl farnesoate for at least three days after treatment. Methyl farnesoate epoxidase activity of homogenates of corpora allata was inhibited by the compounds TH -14 and TH -27. This P450-dependent epoxidase activity was inhibited at less than 10 nM. The results show that the 1,5-disubstituted imidazoles are powerful inhibitors of the last step of juvenile synthesis in this cockroach.  相似文献   

8.
As part of an extensive study on insect antijuvenile hormones (AJH) structurally related to 2,2-dimethyl-7-methoxychromene and 6,7-dimeth-oxy-2,2-dimethylchromene (precocenes I and II, respectively), four furophenols, six furochromenes, three benzofuran derivatives and two benzochromenes were tested for biological effects on Oncopeltus fasciatus and Locusta migratoria. Exposure to ajar deposit of the chemical was used for O. fasciatus and topical application in acetone for L. migratoria, with precocenes I and II as standards for comparison. All compounds were toxic to O. fasciatus and in some cases, this may have concealed any potential AJH activity, which was not observed for any compound tested. Toxicity to L. migratoria was less evident and three of the furochromene derivatives, allprecocene-I (PI) analogues, showed AJH activity seven to ten-fold lower than that of PI. Neither of the benzochromenes tested showed any AJH activity. The results are discussed in terms of the known structure-activity relationships for precocene-like AJH activity.  相似文献   

9.
A series of 27 substituted thio-1,1,1-trifluoropropanones was synthesized by reacting the corresponding thiol with 1,1,1-trifluoro-3-bromopropanone. The resulting sulfides were screened as inhibitors of hemolymph juvenile hormone esterase and α-naphthyl acetate esterase activity of the cabbage looper, Trichoplusia ni, electric eel acetylcholinesterase, bovine trypsin, and bovine α-chymotrypsin. The presence of the sulfide bond increased the inhibitory potency on all of the enzymes tested when compared with compounds lacking the sulfide. In general, the compounds proved to be poor inhibitors of chymotrypsin and moderate inhibitors of trypsin. By varying the substituent on the sulfide, good inhibitory activity was obtained on α-naphthyl acetate esterase, acetylcholinesterase, while some of the compounds proved to be extremely powerful inhibitors of juvenile hormone esterase. The most powerful inhibitor tested was 3-octylthio-1,1,1-trifluoro-2-propanone, with an I50 of 2.3 × 10?9M on JH esterase. This compound showed a molar refractivity similar to that of the JH II backbone, was not toxic to T. ni, and was moderately toxic to mice, with a 48-hr LD50 of >750 mg/kg. It effectively delayed pupation when applied to prewandering larvae of T. ni, as expected for a JH esterase inhibitor. Thus, some members of this series are promising for evaluating the role of JH esterase in insect development. The series also indicates that, by varying the substituent on the sulfide moiety, potent “transition-state” inhibitors can be developed for a wide variety of esterases and proteases.  相似文献   

10.
Six juvenile hormone analogs of the alkyl 3,7,11-trimethyl-2,4-dodecadienoate type were compared as substrates for esterases and oxidases prepared from homogenates of the flesh fly (Sarcophaga bullata) and blow fly (Phormia regina). The esterase system was able to hydrolyze all of the analogs except the isopropyl ester, known commercially as methoprene or ZR-515. This result was consistent with the biological activity of the analogs, methoprene being more effective in preventing pupal-adult ecdysis. The esterases were present in all life stages in both species with the adult (abdomens) containing the highest titers. According to their reaction with paraoxon, the enzymes are classified as C-type esterases. Microsomal oxidases prepared from adult abdomens metabolized all of the juvenile hormone analogs.  相似文献   

11.
Juvenile hormone III was tritium labeled on the methyl ester and utilized with other substrates in an investigation of inhibition and substrate specificity of hemolymph esterases from the cockroach, Blaberus giganteus. The structure of labeled juvenile hormone III was supported both chemically and biochemically. Forty-two potential inhibitors were examined, and the best inhibitors included phosphoramidothiolates and S-phenylphosphates. One of these inhibitors was found useful in hormone biosynthesis studies dealing with the enzymatic conversion of methyl farnesoate to juvenile hormone in corpora allata homogenates. Several commonly used inhibitors of carboxyesterases caused only weak inhibition of JH esterases. Gel filtration elution patterns, inhibitor relationships, and specific activities of the hemolymph esterases indicate that juvenile hormones I and III are degraded by similar if not identical enzymes. In some cases, α-naphthyl acetate and juvenile hormone esterase activity could be differentially inhibited. Hemolymph esterases were not capable of degrading ethyl or isopropyl conjugated esters of two juvenoids or three model substrates.  相似文献   

12.
The spontaneous biosynthesis of methyl (2E,6E)-(10R)-10,11-epoxy-3,7,11-trimethyldodeca-2,6-dienoate (juvenile hormone III; JH III) in excised corpora allata of Periplaneta americana was inhibited by a number of synthetic prop-2-ynyl ethers and 1,3-benzodioxole derivatives. One structurally diverse group of compounds inhibited only the final biosynthetic enzyme methyl farnesoate epoxidase (EC.1.14.14.–) at low to moderate concentrations, but at higher concentrations, also inhibited methyl farnesoate (MF) formation, causing an accumulation of MF in the concentration range 10 to 100 μM. For a second, more limited, group of compounds, there was close congruence between the inhibition of JH III biosynthesis and that of total ester (MF plus JH III) biosynthesis over their effective inhibitory concentration ranges. In contrast to the first group, there was no accumulation of MF and these compounds evidently inhibited JH III biosynthesis, at the level of either farnesoic acid esterification by O-methyl transferase (EC.2.1.1.–), or at an earlier step in the biosynthetic pathway that remains to be elucidated.  相似文献   

13.
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   

14.
Biosynthesis of juvenile hormone in the tobacco hornworm, Manduca sexta, is inhibited by the bisthiolcarbamate juvenoid N-ethyl-1,2-bis(isobutylthiolcarbamoyl)ethane both in vitro and in vivo. In vitro an extremely steep dose-response curve was obtained with an ID50 value of 6 × 10?6M. However, in vivo topical treatment with the compound resulted in mild JH antagonistic symptoms, suggesting rapid metabolism of the compound. In agreement with results from metabolic studies performed on plants and in mammals, sulfoxidation of the thiocarbamate S-(4-chlorobenzyl)N,N-diethylthiocarbamate resulted in an enhanced inhibitory effect on JH biosynthesis in vitro. This suggests that the corresponding thiocarbamate sulfoxides may act as intermediates in carbomylating critical thiol sites important in the terpenoid biosynthesis pathway. Furthermore, this study shows that these prototype compounds are interesting tools for further investigation of chemical inhibition of JH biosynthesis in insects.  相似文献   

15.
Rationally planned structural modifications were carried out on benzylphenols and benzyl-1,3-benzodioxoles described as fly chemosterilants and as anti-juvenile hormones. The introduction of a prop-2-ynyloxy group at various sites of the molecule resulted in compounds with a moderate inhibitory action on cytochrome P-450 mono-oxygenases, as measured by aldrin epoxidation. One compound, 5-(4-methoxybenzyl)-6-prop-2-ynyloxy-1,3-benzodioxole, revealed chemosterilant activity on Phormia regina, but its activity was less than that of the parent compounds. 2,4-Di-tert-butyl-6-[4-(3-methoxy-3-methylbutoxy)benzyl]phenol, which possessed a juvenoid structure, revealed no juvenile hormone (JH) activity but showed a high sterilant effect against Dysdercus cingulatus. In contrast to the parent substances, none of the tested compounds showed a detectable anti-JH effect in the Galleria assay. 8-Methoxy-2,3-methylenedioxydibenz[b,e]oxepine, a hitherto undescribed fused heterocyclic ring system, was devoid of activity, indicating the importance of free rotation and/or molecular flexibility. In spite of the moderate activities of these compounds, the manifold biological potential of the quinone-methide mechanism justifies further research on these lines.  相似文献   

16.
Small (70 mg) Boarmia selenaria larvae fed for 4 days on avocado leaves or alfalfa dipped in aqueous diflubenzuron suspensions suffered from severe developmental disturbances. Similar results were obtained with leaves sprayed in an avocado orchard, with which, in addition, the considerable persistence of diflubenzuron under field conditions could be demonstrated. The substance was also active by topical application against large (500–600 mg) B. selenaria larvae, whereas by contact it was only moderately toxic. Some other non-conventional control agents, viz., the antifeedant AC-24055 and several juvenile hormone analogues, were of medium and negligible activity, respectively, against this insect.  相似文献   

17.
A new series of 5-(substituted phenoxy)pentyl 3-pyridyl ethers induced precocious metamorphosis in larvae of the silkworm, Bombyx mori. Both 2- and 4-pyridyl ethers were inactive, indicating that the 3-pyridine moiety was essential for the activity. Octyl, dodecyl and farnesyl 3-pyridyl ethers had no activity. Among the compounds tested so far, 5-(4-propylphenoxy)pentyl 3-pyridyl ether showed the highest activity. The activity fell off with increasing or decreasing length of the carbon chain between two oxygen atoms. Introduction of a methyl group at the 6 position of the pyridine ring completely eliminated the activity. Precocious metamorphosis induced by 3-pyridyl ethers was fully reversible by a simultaneous application of a small amount of tebufenozide, an ecdysteroid agonist, or methoprene, a JH agonist. © 1998 SCI.  相似文献   

18.
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   

19.
Of six juvenile hormone analogs of the alkyl 3,7,11-trimethyl-2,4-dodecadienate type, only the isopropyl ester was strongly morphogenic in the house fly, Musca domestica L. In vitro assays revealed that house fly microsomes contain B-esterases as well as oxidases which metabolize such analogs. However, these esterases did not hydrolyze the isopropyl ester, ZR-515. Enzymes prepared from larvae, pupae, and adults were all active and there was evidence that in the late larval stage the esterase activity was cyclic, showing a minimum in the early third instar and a maximum a few hours later. When microsomes from two susceptible and two resistant house fly strains were compared for metabolic activity against the juvenile hormone analogs, those from the resistant strains were 1.3 to 20 × higher in oxidase activity but there was no difference in esterase activity. The oxidative metabolism of two analogs ZR-515 and 512 was greatly enhanced when the flies were induced with phenobarbital but there was no enhancement in metabolism of three of the remaining analogs and only a slight enhancement of a fourth. It is concluded that the insecticidal action of ZR-515 is largely due to its stability in the presence of the house fly esterases.  相似文献   

20.
The fluorescent insect growth regulator 5[[[5-(dimethylamino)-1-naphthalenyl]amino]-1,3-benzodioxole (DNSAB) forms a metabolite complex with house-fly microsomal cytochrome P-450. Formation of the metabolite complex is dependent on the presence of NADPH and O2; NADH supports the reaction at a reduced rate. The presence of antibodies to house-fly cytochrome c (P-450) reductase in reaction mixtures inhibits the complex formation, indicating that the reductase is necessary for transfer of electrons from NADPH to cytochrome P-450 to complete the reaction. In the oxidized form, the metabolite complex has a single absorbance maximum at 431 nm, whereas the reduced form has two absorbance maxima at 426 (major) and 455 nm (minor). The pH of the media affects the extinction of the 426- and 455-nm Soret bands; increased pH decreases the extinction of the 426-nm band and increases the extinction of 455-nm band. Formation of the DNSAB metabolite-cytochrome P-450 complex decreases the amount of CO-reactive cytochrome P-450 by 24%. The metabolite complex is not dissociable by treatment with ferricyanide or by using centrifugation techniques. Dissociation is accomplished by addition of DNSAB to the oxidized metabolite complex. Kinetic analysis of the complex formation gives apparent Km and Vmax values at 2.55 ± 1.0 μM and 1.1 ± 0.4 × 10?2 ΔA min?1 nmol?1 cytochrome P-450, respectively. Addition of juvenile hormone [(E,E)-cis-methyl-10,11-epoxy-7-ethyl-3,11-dimethyl-2,6-tridecadienoate; JH] to the reaction medium competitively inhibits the formation of the metabolite complex giving an inhibition constant of 16 μM. DNSAB synergized the lethal effects of JH against Aedes aegypti larvae threefold; however, JH did not synergize DNSAB. These data suggest that DNSAB may acquire its hormonal qualities by complexing a species of cytochrome P-450 that metabolizes JH, thereby prolonging the in vivo lifetime of this hormone.  相似文献   

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