艾氏剂环氧化酶及细胞色素P-450对小菜蛾抗药性发展的影响

本文对室内长期饲养的小菜蛾(Plutella xylostella L.)敏感品系和田间采集的抗性种群体内的艾氏剂环氧化酶及细胞色素P-450进行了比较研究。结果证明,艾氏剂环氧化酶在感性和抗性小菜蛾间存在着量及质的差异。 抗性种群的艾氏剂环氧化酶的Vmax和Km值分别为感性品系的5.4倍和6.5倍。抗性种群的细胞色素P-450的含量是感性品系的1.1-1.3倍。艾氏剂环氧化酶在量上及质上的差异及细胞色素P-450含量的提高是导致小菜蛾抗药性发生与发展的重要机制之一。而且质的差异较之量的差异可能起着更为重要的作用,     

棉铃虫的细胞色素P-450单加氧酶系与菊酯类杀虫剂抗药性的关系(英文)

细胞色素Ｐ－４５０单加氧酶系在昆虫抗药性中起重要作用。本文研究了棉铃虫抗性品系与敏感品系间细胞色素Ｐ４５０含量、对－硝基茴香醚Ｏ－脱甲基酶和艾氏剂环氧化酶的差异。结果表明：抗性品系中细胞色素Ｐ－４５０含量、对－硝基茴香醚Ｏ－脱甲基酶活性分别是敏感品系的１．７１倍和２．２１倍,而艾氏剂环氧化酶活性仅为１．３５倍。因此细胞色素Ｐ－４５０含量和对－硝基茴香醚Ｏ－脱甲基酶在棉铃虫抗菊酯品系中起重要作用。进一步讨论了不同抗性品系间抗性机制不同的原因。     

氰戊菊酯和苯巴比妥钠对敏感和抗性棉铃虫中肠多功能氧化酶系的诱导作用

用苯巴比妥钠（2mg/g）和氰戊菊酯（0.2mg/g）拌饲料处理,对敏感品系棉铃虫Helicoverpa armigera中肠的细胞色素P450和细胞色素c还原酶含量均具有明显的诱导作用（两者都使细胞色素P450含量提高了2.24倍,使细胞色素c还原酶的含量分别提高1.33和1.40倍）,但对细胞色素b5诱导作用不显著（仅为对照的1.23和1.15倍）;此外,苯巴比妥钠对敏感棉铃虫中肠的艾氏剂环氧化酶活性和甲氧试卤灵-O-脱甲基酶活性也有显著的诱导作用（分别提高了2.75和2.66倍）,但对7-乙氧香豆素-O-脱乙基酶活性没有诱导作用,而氰戊菊酯对敏感棉铃虫中肠的艾氏剂环氧化酶活性则有2.02倍的诱导作用。同一浓度的苯巴比妥钠和氰戊菊酯使抗性品系棉铃虫中肠的细胞色素P450含量分别提高1.21和1.15倍,使细胞色素c还原酶含量分别提高1.48和1.86倍（差异显著）,但是细胞色素b₅含量没有明显变化（分别为对照的1.15和0.98倍）;此外,氰戊菊酯能使抗性棉铃虫中肠的艾氏剂环氧化酶活性提高1.53倍,但苯巴比妥钠对该酶活性则有明显抑制作用。     

增效醚（PBO）对棉铃虫细胞色素P450的抑制作用及对拟除虫菊酯的？…

在增效醚（ＰＢＯ）对棉铃虫Ｊｅｌｉｃｏｖｅｒｐａ ａｒｍｉｇｅｒａ３龄细虫处理后的不同时段,细胞色素Ｐ４５０的含量受到不同程度的抑制,在处理后１ｈ,细胞色素Ｐ４５０的含量仅为对照的４３．９％,至处理后１２ｈ,细胞色素Ｐ４５０的含量下降到最低点,仅为对照的２３．４％,而处理后１８～２４ｈ,细胞色素Ｐ４５０被抑制的程度有所减弱,其含量分别为对照的８５．８％和７０．０％。生物测定结果表明,ＰＢＯ对所测定     

小菜蛾对三氟甲吡醚的抗性风险评价与抗性生化机制研究

【目的】明确小菜蛾Plutella xylostella(Linnaeus)对三氟甲吡醚的抗性风险和抗性生化机制,为三氟甲吡醚的合理使用提供科学依据。【方法】采用TabashnikMc Gaughey的阈性状分析方法评估小菜蛾对三氟甲吡醚的抗性风险;采用浸叶法测定增效剂(胡椒基丁醚、磷酸三苯酯和顺丁烯二酸二乙酯)对三氟甲吡醚的增效作用,通过酶动力学方法测定了小菜蛾对三氟甲吡醚抗性和敏感品系的谷胱甘肽-S-转移酶、酯酶和多功能氧化酶的活性。【结果】经过18代次筛选,小菜蛾种群对三氟甲吡醚的抗性水平上升至14.8倍,小菜蛾对三氟甲吡醚的抗性现实遗传力(h~2)为0.1558;当h~2=0.155 8时,在致死率为50%-90%的选择压力下,预计小菜蛾对三氟甲吡醚抗性增加10倍分别需要16.1-7.3代。在小菜蛾三氟甲吡醚抗性品系中,酯酶和多功能氧化酶比活力均显著高于敏感品系,分别为敏感品系的1.34倍和1.45倍;谷胱甘肽-S-转移酶比活力与敏感品系的无显著差异。抗性品系的酯酶抑制剂磷酸三苯酯和多功能氧化酶抑制剂胡椒基丁醚对三氟甲吡醚具有明显增效作用,增效倍数分别为1.21倍和1.43倍;谷胱甘肽-S-转移酶抑制剂顺丁烯二酸二乙酯对三氟甲吡醚没有明显增效作用。【结论】小菜蛾对三氟甲吡醚产生抗性的风险较大,酯酶和多功能氧化酶活性的升高可能是小菜蛾对三氟甲吡醚产生抗性的重要机制。     

棉铃虫6龄幼虫中肠与脂肪体微粒体P450酶系的比较

报道了棉铃虫6龄幼虫中肠和脂肪体微粒体P450酶系的组成与加单氧酶活性。与脂肪体微粒体相比,中肠策粒体具有更高的细胞色素P450,细胞色素b5和NADPH－细胞色素P450还原酶含量,表现出较高的艾氏剂环氧化酶和对－硝基苯甲醚O－脱甲基酶活性。SDS－PAGE电泳显示,中肠与脂肪体微粒体介于P450分子量范围内（45－60kDa)的蛋白图谱有所不同,反映出中肠和脂肪体微粒体蛋白组成存在差异。通过对－硝基苯甲醚O－脱甲基酶的动力学分析发现脂肪体微粒体的对－硝基苯甲醚O－脱甲基酶对底物有更强的亲和性,表明不同组织来源的P450同功酶存在质的不同。     

小菜蛾对定虫隆的抗性生化机制初探

以定虫隆汰选的抗性指数为23.78倍抗性种群(CH-R),并以上海田间种群(SH-R,对定虫隆的抗性指数为9.16倍)作为参比种群,研究小菜蛾Plutella xylostlla(L.)对定虫隆的抗性机制,结果表明：CH—R种群多功能氧化酶O-脱甲基活力比相对敏感种群(SZ-S)提高1倍,而SH-R种群多功能氧化酶O-脱甲基活力虽有所提高,但与SZ-S种群相比差异并不显著;CH-R和SH-R种群羧酸酯酶比活力均明显高于Sz-S种群,分别为SZ-S种群的4.61和2.18倍,且CH-R种群的Km仅为SZ-S种群的1/20;酸性磷酸酯酶和碱性磷酸酯酶比活力种群间无明显差异;CH-R种群的几丁质酶活力降低48%,酚氧化酶活力降低60%。说明小菜蛾对定虫隆的抗性机制具有多因子性,多功能氧化酶解毒代谢能力的提高可能是主导抗性机制之一,羧酸酯酶、几丁质酶和酚氧化酶也参与了小菜蛾对定虫隆的抗性。     

甜菜夜蛾不同世代对氯氟氰菊酯抗性减退及多功能氧化酶系活性变化

在室内用人工饲料连续饲养和未用药剂筛选条件下,测定了采自田间对氯氟氰菊酯产生高水平抗性甜菜夜蛾Spodoptera exigua (Hübner)种群的抗药性及其多功能氧化酶系活性的变化情况。用点滴法测定不同世代3龄幼虫抗性结果为：室内F₁代LD₅₀值为 0.9672 μg/头,抗性倍数为4 836.0倍,以后各世代逐渐降低,至F₄₃代LD₅₀值为0.0325μg/头,抗性倍数为162.5倍,抗性水平下降了29.8倍。用浸叶法测定不同世代3龄幼虫抗性结果为：室内F₁代LC₅₀值为185.6 mg/L,抗性倍数为964.7倍,以后各世代也逐渐降低,至F₄₃代LC₅₀值为9.2 mg/L,抗性倍数为47.8倍,抗性水平下降了20.2倍。与敏感品系相比,该田间种群室内饲养至F₄₃代仍处于较高的抗性水平,抗性减退缓慢,很难恢复到敏感水平。测定甜菜夜蛾田间种群室内F₂、F₂₀和F₄₁代及敏感品系5龄幼虫中肠微粒体甲氧试卤灵-O-脱甲基酶、乙氧试卤灵-O-脱乙基酶、芳香基羟基化酶及艾氏剂环氧化酶活性,结果表明：与敏感品系相比,田间种群甲氧试卤灵-O-脱甲基酶和艾氏剂环氧化酶的活性仅F₂代显著较高,F₂₀和F₄₁代差异不显著,乙氧试卤灵-O-脱乙基酶和芳香基羟基化酶的活性F₂、F₂₀和F₄₁代均显著较高。结果提示甜菜夜蛾抗性水平可能与其体内微粒体多功能氧化酶系活性有密切关系。     

西花蓟马对吡虫啉抗性机制的研究

为了解大规模应用吡虫啉防治西花蓟马Frankliniella occidentalis(Pergande)的抗性风险,本文研究了吡虫啉与多杀菌素和啶虫咪的交互抗性并比较了多功能氧化酶系(mixed-function oxidases,MFO)的3个组分细胞色素P450、细胞色素b5、甲氧试卤灵O脱甲基酶(methoxyresorufin O-demethylase,MROD)在西花蓟马敏感品系(S)、抗吡虫啉品系(BK)和北京田间品系(BJ)中的含量以及活性。生物测定表明北京田间品系(BJ)对多杀菌素已经产生了较高抗性(RR50=35.38),而对啶虫咪(RR50=3.05)和吡虫啉(RR50=1.82)处于敏感,交互抗性研究结果表明西花蓟马对吡虫啉与多杀菌素(RR50=1.31)和啶虫咪(RR50=3.20)无交互抗性。生化研究表明:西花蓟马抗吡虫啉品系的3个组分含量均显著高于S品系西花蓟马的含量(P<0.05),其中细胞色素P450在是S品系WFT的4.5倍,细胞色素b5含量是S品系WFT的4.23倍,MROD活性是S品系WFT的5.99倍,表明多功能氧化酶系与西花蓟马对吡虫啉的抗药性密切相关。     

杀虫双和杀螟丹选育对小菜蛾抗药性的形成及其抗性机制

用杀虫双和杀螟丹在实验室以点滴法处理小菜蛾Plutella xylostella L.四龄幼虫,以连续继代药剂淘汰选育其抗药性。至35代,药剂汰选的小菜蛾对杀虫双和杀螟丹的抗药性较选育前正常品系分别提高了51倍和25倍。其抗药性的形成发展均呈S形,可认为已成为抗性品系。以有机磷、氨基甲酸酯、拟除虫菊酯及有机氮等11种杀虫剂测试抗杀虫双小菜蛾品系和抗杀螟丹小菜蛾品系对常用药剂的敏感度结果表明：对杀虫双、杀螟丹和杀虫环之间有较严重的正交互抗性;对敌敌艮、马拉硫磷和杀螟松有轻微交互抗性产生;对溴氰菊酯、氯氰菊酯、氯菊酯和灭多威、久效威等药剂更加敏感,呈负交互抗性。用聚丙烯酰胺凝胶电泳(PAGE)法测定表明,抗药性产生与特异性酯酶的形成有一定关系。用比色法和酸度法测定,抗性品系的乙酰胆碱酯酶(AchE)活性降低,羧酸酯酶(CarE)活性无差异。加增效剂Pb和SV₁：于四龄幼虫表皮,对抗杀虫双小菜蛾晶系分别有6.28及1.45倍的增效作用;对抗杀螟丹小菜蛾品系分别有4.85及1.39倍的增效作用,可见多功能氧化酶(MFO)为小菜蛾抗杀虫双和抗杀螟丹的重要因子。     

CYTOCHROME P450 MONOOXYGENASES ASSOCIATED WITH PYRETHROID RESISTANCE IN HELICOVERPA ARMIGERA (HÜBNER)

Abstract  The relationship between the cytochrome P-450 (cytP⁴⁵⁰ monooxygenase and insecticide resistance mechanisms in Helicoverpa armigera was studied. The level of cytP450 and activity of p -ni-troanisole ( p -NA) O-demethylase in resistant strain were 1. 71 times and 2. 21 times respectively higher as compared with those of the susceptible strain. Aldrin epoxidase activity showed 1. 35 fold strain difference. Therefore aldrin epoxidase might not be important for H. armigera resistance mechanism, the level of cytP450 and activity of p -NA O-demethylase might play a vital role in H. armigera resistance mechanisms. The reason of different resistance mechanisms among different H. armigera resistant strains is discussed.     

Differences in the cytochrome P-450S from resistant and susceptible house flies

A comparison of difference spectra formed with microsomal cytochrome P-450 from a susceptible and a resistant strain of house flies shows both quantitative and qualitative differences. The differences are similar to those observed for the same spectra between normal and phenobarbital- or 3-methylcholanthrene-treated mammals. The relationship of these findings to resistance, synergism, and cytochrome P-450 in the house fly is discussed.     

Oxidase activities in macrocyclic-resistant and -susceptible Haemonchus contortus

The role of oxidative metabolism in resistance to macrocyclic lactones in Haemonchus contortus was examined by measuring activities toward 2 model cytochrome P450 substrates, aldrin and ethoxycoumarin, in a susceptible and a resistant isolate of the parasite. Microsomal preparations from larvae and adults of the 2 isolates showed no differences in levels of NADPH- or cumene hydroperoxide-supported aldrin epoxidase or ethoxycoumarin O-deethylase activities. Intact adult nematodes showed an ability to catalyze the epoxidation of significant amounts of aldrin, although the nature of the enzyme group responsible was unknown. This epoxidase activity was greater in adults of the susceptible isolate. It is apparent that oxidase activities toward the 2 substrates are not enhanced in the resistant isolate, suggesting that the observed resistance to macrocyclic lactones may not involve enhanced oxidative metabolism.     

Phenobarbital-type induction of cytochrome P-450 in liver microsomes by perfluorodecalin

Cytochrome P-450 induction in hepatic microsomes after injections of rats with a fluorocarbon emulsion containing perfluorodecalin was studied in comparison with phenobarbital and methylcholanthrene type inductions. It was shown that perfluorodecalin injection as well as the phenobarbital one cause an increase in the cytochrome P-450 content, NADPH-cytochrome c reductase activity, the rates of benzphetamine N-demethylation and aldrin epoxidation in the microsomes. Using the Ouchterlony double immunodiffusion test with antibodies against cytochrome P-450b, an immunological identity of cytochrome P-450 isoforms during perfluorodecalin and phenobarbital inductions was shown. Upon "rocket" immunoelectrophoresis the recovery of cytochrome P-450 which is immunologically indistinguishable from cytochrome P-450b was approximately 72% in perfluorodecalin-induced microsomes. The activity of benzphetamine demethylase and aldrin epoxidase was inhibited by antibodies against cytochrome P-450b. These results suggest that in rat hepatic microsomes perfluorodecalin induces the cytochrome P-450 isoform whose immunological properties and substrate specificity correspond to those of phenobarbital-type cytochrome P-450.     

Induction of multiple cytochrome P-450 species in housefly microsomes--SDS-gel electrophoresis studies.

1. Microsomal fractions isolated from various housefly strains have been characterized with respect to multiple forms of cytochrome P-450 by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. 2. Susceptible NAIDM houseflies were pretreated with known inducers of cytochrome P-450, and their microsomal electrophoretic profiles were compared to control NAIDM microsomes, using as standards partially purified cytochrome P-450s from noninduced NAIDM houseflies. 3. Tentatively, at least five different species of cytochrome P-450 may exist in the NAIDM housefly strain. 4. A comparison of the microsomal electrophoretic profile of different housefly strains also indicates the presence of at least two additional cytochrome P-450 species. 5. Induction with alpha-pinene and phenobarbital was expressed by a shift of the maximum absorbance at 452 nm in the CO-difference spectrum to lower wavelengths in the NAIDM strain; whereas, beta-naphthoflavone, although increasing the amount of cytochrome P-450, did not change the wavelength of maximum absorbance. 6. Cytochromes of the P-452 type appear to predominate in the susceptible NAIDM strain, while cytochromes of the P-450 and P-448 types predominate in resistant strains.     

The solubilization and separation of two forms of microsomal cytochrome P-450 from the house fly, Musca domestica l.

Microsomes prepared from house fly abdomens were solubilized with sodium deoxycholate and resolved on a DEAE cellulose column into two fractions containing cytochrome P-450. On the basis of spectral characteristics the cytochrome in a fraction eluting with 0.3M KCl is different from that eluting with 0.5M KCl. The two forms of P-450 were found in both susceptible and resistant strains of house flies. The P-450 in the 0.5M KCl eluting fraction appears to be more unstable than that in the 0.3M fraction. These results are in disagreement with those of other workers who have concluded that only one of two possible forms of cytochrome P-450 is present in a given strain of the house fly.     

家蝇对拟除虫菊酯农药的抗性机制

本文对二氯苯醚菊酯和溴氰菊酯分别选择的高抗性家蝇(Musca domestica vicina)品系2Cl-R及Dec-R的抗性机制进行了研究.应用生物测定、增效剂,体内试验的表皮穿透作用、离体条件的解毒酶系活性的增加以及家蝇头部ATP酶活力的研究结果表明,两种拟除虫菊酯高抗性家蝇品系的表皮穿透性均比正常品系NP为慢,特别是Dec-R品系极慢.酯酶和多功能氧化酶及其末端的细胞色素P-450的活性在两个抗性品系中都比NP品系有不同程度的增高,但2Cl-R品系以氧化酶为主,而Dec-R品系似以酯酶占优势.Dec-R品系的Na⁺—K⁺-ATP酶活力低于NP品系的46%,而2Cl-R品系与NP品系相等.Mg²⁺-ATP酶活性在两个抗性品系中均高于正常品系.Mg²⁺-ATP酶可能也是拟除虫菊酯的一个重要靶标部位.     

Expression of cytochrome P-450lpr is developmentally regulated and limited to house fly.

Expression of house fly cytochrome P-450lpr was examined using immunoblotting in male and female adult LPR house flies, mixed sex adult house flies at 12 different ages, larvae, and pupae. P-450lpr was expressed in both male and female adult house flies. P-4501pr was clearly present in all adult stages examined, was barely detectable in pupae, and could not be detected in larvae. Thus, cytochrome P-450lpr is developmentally regulated and present in both sexes of house fly. Expression of cytochrome P-450, immunologically homologous to house fly cytochrome P-4501pr, was examined in other species using immunoblot analysis. Eleven animal species were tested in the orders Diptera, Hymenoptera, Lepidoptera, Orthoptera, Acari, and Rodentia, using microsomes in some species from both induced and noninduced animals or insecticide-resistant and susceptible strains. P-450lpr appears to be restricted to house flies, as none of these species contained cytochrome P-450 that reacted with antiserum to cytochrome P-450lpr.