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1.
马尾松毛虫蛋白质、核酸酶和羧酸酯酶与耐药性的关系   总被引:5,自引:3,他引:2  
马尾松毛虫(Dendrolimus punctatus Walker)幼虫蛋白质含量、羧酸酯酶和多酚氧化酶活力与虫龄大小成正相关;氰戊菊酯处理后,兴奋期的蛋白质含量和羧酸酯酶活力上升,到抑制期均降低到正常虫体的水平,而多酚氧化酶的变动不大。正常虫体中脱氧核糖核酸酶(DNase)和核糖核酸酶(RNase)的活力存在差异:DNase从3—5龄幼虫随虫体增大而上升,到6龄时明显降低;RNase与虫龄大小成负相关;氰戊菊酯处理后,DNase便开始下降并低于正常虫体的水平,而RNase在兴奋期上升,到抑制期下降亦低于正常虫体水平。结果说明,除多酚氧化酶外,蛋白质、核酸酶和羧酸酯酶均与耐药性存在一定的相关性,研制酶的抑制剂具有实用意义。根据毒力测定结果,马尾松毛虫幼虫随虫龄增大而耐药力增加,氰戊菊醋对5龄幼虫是3龄的2.8倍,6龄是4龄的2.3倍。因此,掌握在4龄前进行药物防治是合理的。  相似文献   

2.
马尾松毛虫过氧化氢酶及过氧化物酶与耐药性的关系   总被引:19,自引:2,他引:17  
陈尚文 《昆虫学报》2001,44(1):9-14
马尾松毛虫Dendrolimus punctatus幼虫体内存在着过氧化氢酶(CAT)和过氧化物酶(POD)。4龄幼虫的CAT和POD活力较大,其次是6龄幼虫,5龄幼虫的CAT和POD活力较4龄和6龄幼虫低。醚菊酯(etofenprox)处理后,在兴奋期(30 min),CAT和POD活力水平上升。4龄和6龄幼虫在抑制期(50 min以后),CAT和POD活力呈波动式上升,接近死亡时下降。5龄幼虫的CAT和POD活力呈波动式上升,接近死亡时下降。5龄幼虫的CAT在抑制期保持比正常虫体高的活力。结果表明,马尾松毛虫4龄、5龄和6龄幼虫与耐药性存在一定的相关性,研制酶的抑制剂具有实用意义。根据毒力测定结果,马尾松毛虫幼虫对醚菊酯的耐药力,5龄是4龄的1.43倍,6龄是4龄的1.72倍。因此,药物防治的合理时期应掌握在4龄以前较适宜。  相似文献   

3.
菜青虫不同虫态及虫龄的多酚氧化酶性质比较   总被引:18,自引:2,他引:18  
初步比较了菜青虫Pieris rapae (L.)不同虫态及虫龄的多酚氧化酶(polyphenol oxidase)的性质。结果表明,不同虫态及虫龄的多酚氧化酶活力有很大的不同,其中以5龄幼虫酶活力最高,蛹酶活力最低。酶活力大小依次为: 5龄幼虫> 预蛹>4龄幼虫>3龄幼虫>蛹。以邻苯二酚为底物,研究了pH对多酚氧化酶活力的影响,结果表明酶催化底物氧化均有一个最适pH区域,不同虫态及虫龄的多酚氧化酶最适pH基本相同,其值为7.0±0.2 。不同虫态及虫龄的多酚氧化酶催化底物氧化的最适温度有很大的差异。3龄、4龄、5龄幼虫、预蛹和蛹的多酚氧化酶活力的最适温度分别为36.0±0.5℃、38.5±1.0℃、43.0±1.0℃、45.5±1.0℃和50.0±1.5℃,说明蛹期的多酚氧化酶活力的最适温度较高。进一步比较催化底物氧化反应的活化能,测得3龄、4龄、5龄幼虫、预蛹和蛹的多酚氧化酶活化能分别为:4 3.10±0.28、36.50±0.27、25.79±0.32、30.10±0.21和58.88±0.39 kJ/mol 。通过测定不同虫态及虫龄的多酚氧化酶催化邻苯二酚和L-多巴氧化反应的动力学特征参数,比较了不同虫期的酶对底物的亲和力。  相似文献   

4.
为更好地指导生产,本文研究了不同虫态烟蚜Myzus persicae对吡虫啉和丁硫克百威敏感性及其与羧酸酯酶、多功能氧化酶、谷胱甘肽S-转移酶比活力相关性。结果表明,3龄若虫对吡虫啉敏感性水平最低,4龄若虫对丁硫克百威敏感性水平最低。不同虫态烟蚜解毒酶活力随龄期逐渐增强,之后逐渐减弱,3龄若虫高于其他任何虫态,且多功能氧化酶和羧酸酯酶比活力与杀虫剂敏感性间存在强的负相关性。田间最佳防治虫态为1龄若虫、2龄若虫和成虫。  相似文献   

5.
【目的】明确甜菜夜蛾Spodoptera exigua(Hübner)不同龄期幼虫对甲氨基阿维菌素苯甲酸盐和毒死蜱的敏感性及其与羧酸酯酶、多功能氧化酶、谷胱甘肽S-转移酶和乙酰胆碱酯酶活性的相关性。【方法】采用室内生物测定方法检测甜菜夜蛾不同龄期幼虫对药剂的敏感性,并检测了不同龄期幼虫体内羧酸酯酶、多功能氧化酶、谷胱甘肽S-转移酶和乙酰胆碱酯酶的活力。【结果】在所测定的5个龄期中,随龄期增加,敏感性逐渐降低,其中1~5龄幼虫对甲氨基阿维菌素苯甲酸盐的LC50分别为0.1010、0.3561、0.7568、1.4325和8.4390 mg/L,对毒死蜱的LC50分别为27.4632、46.8495、87.5222、129.3217和1 356.6770 mg/L。单头幼虫的羧酸酯酶、多功能氧化酶、谷胱甘肽S-转移酶和乙酰胆碱酯酶活力随虫龄的增加而提高,与龄期间对药剂的敏感性呈负相关(由于外源化合物摄入量减少,5龄单头幼虫的多功能氧化酶活力略有降低)。【结论】甜菜夜蛾不同龄期幼虫对药剂的敏感性存在非常明显的差异,在田间防治中,应选择对杀虫剂敏感性较高的低龄幼虫作为最佳防治时期。  相似文献   

6.
棉铃虫抗药性的生理生化机制研究   总被引:12,自引:2,他引:10  
张友军  张文吉 《昆虫学报》1997,40(3):247-253
本文报道了棉铃虫Helicoverpa armigera田间抗性种群对杀虫剂抗药性的生理生化机制。抗性种群(HJ-R)5龄幼虫羧酸酯酶、谷胱甘肽转移酶、多功能氧化酶活力均明显高于相对敏感种群(HD-S)。两种群乙酰胆碱酯酶对杀虫剂敏感性没有显著差异。HJ-R种群的腹神经索对氰戊菊酯表现了2-3倍的神经不敏感性。HJ-R种群对氨基甲酸酯类杀虫剂的抗性主要是由代谢机制引起,其中多功能氧化酶可能起主导作用;对菊酯的抗性是由多功能氧化酶、酯酶、以及神经不敏感性几个因子综合作用的结果。  相似文献   

7.
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。  相似文献   

8.
羧酸酯酶介导的小菜蛾对氟虫腈的抗性   总被引:3,自引:0,他引:3  
【目的】羧酸酯酶(carboxylesterases, CarEs)是昆虫重要的解毒代谢酶之一,可以介导靶标昆虫对多种杀虫剂的代谢抗性。本研究检测了羧酸酯酶对小菜蛾Plutella xylostella 抗药性的介导功能,旨在阐明羧酸酯酶在小菜蛾代谢解毒中的生理生化和分子机理。【方法】采用点滴法测定氟虫腈对小菜蛾敏感种群和抗氟虫腈种群的毒力,以及羧酸酯酶抑制剂磷酸三苯酯(triphenyl phosphate, TPP)对氟虫腈的增效作用;以LC30和LC50浓度的氟虫腈处理抗性小菜蛾,测定药剂处理后CarEs酶活性的变化;利用qRT-PCR技术分析Pxae22和Pxae31两个基因在小菜蛾不同发育阶段、组织和种群的表达模式;利用dsRNA干扰Pxae22和Pxae31后观察基因的表达变化和小菜蛾3龄幼虫对药剂敏感性的变化。【结果】TPP可以削弱小菜蛾3龄幼虫对氟虫腈的抗性,增效倍数约为6倍;使用较低剂量(LC30和LC50)氟虫腈处理小菜蛾3龄幼虫后,处理组CarEs比活力明显高于对照,提示氟虫腈对小菜蛾CarEs活性具有诱导作用。对羧酸酯酶基因Pxae22和Pxae31在小菜蛾不同发育阶段、4龄幼虫不同组织和不同种群3龄幼虫中的表达模式分析发现,这两个基因在小菜蛾4龄幼虫中的表达量最高;在4龄幼虫中以中肠组织中的表达量较高,头、表皮、脂肪体中的表达量很低; 抗性种群中的表达量显著高于敏感种群。通过干扰 Pxae22和 Pxae31后的qRT-PCR验证,两个基因的表达量均显著降低,进一步的氟虫腈毒力测定发现,干扰P xae22和 Pxae31后的小菜蛾3龄幼虫对氟虫腈的敏感性分别增加了1.63倍和1.73倍。【结论】羧酸酯酶在小菜蛾对氟虫腈解毒代谢中具有重要作用;Pxae22和Pxae31是小菜蛾的两个抗性相关基因,其表达水平的变化直接影响小菜蛾对氟虫腈的敏感性。  相似文献   

9.
棉铃虫不同虫态及虫龄血淋巴中酚氧化酶活力的比较   总被引:1,自引:0,他引:1  
分别测定了棉铃虫Helicoverpa armigeraHübner不同虫态及虫龄血清和血细胞中酚氧化酶(phenoloxidase,PO)的活力。结果显示血清和血细胞中都有酚氧化酶活性,且血细胞中高于血清中。不同虫态及虫龄的血清和血细胞中酚氧化酶活力有很大的不同,血清和血细胞中酚氧化酶活力变化规律一致。3龄幼虫酶活力最高,5龄幼虫最低。酶活力大小依次为:3龄幼虫>预蛹>4龄幼虫>蛹>5龄幼虫  相似文献   

10.
土荆芥精油预处理后小菜蛾幼虫对氟虫腈敏感度的变化   总被引:1,自引:0,他引:1  
采用微量点滴法测定了土荆芥Chenopodium ambrosioides精油预处理前后氟虫腈对小菜蛾Plutella xylostella 2龄幼虫的触杀作用,采用生化分析方法研究了土荆芥精油预处理前后小菜蛾幼虫体内乙酰胆碱酯酶(AChE)、羧酸酯酶(CarE)和谷胱甘肽-S-转移酶(GSTs)的比活力。研究结果表明,1μL·mL^-1和10μL·mL^-1的土荆芥精油预处理可增加小菜蛾幼虫对氟虫腈的敏感度,LC50分别为氟虫腈单用时的0.66倍和0.44倍;当用1μL·mL^-1和10μL·mL^-1土荆芥精油预处理小菜蛾2龄幼虫2h后,再用氟虫腈致死中量点滴处理,小菜蛾存活幼虫体内AChE、CarE和GSTs比活力均低于氟虫腈单独处理组。研究结果说明土荆芥精油预处理对氟虫腈的增效作用可能与主要抗性相关酶系活性变化有关。  相似文献   

11.
萧氏松茎象幼虫龄数的估测   总被引:4,自引:0,他引:4  
室内和林间调查的结果表明 ,萧氏松茎象HylobitelusxiaoiZhang幼虫期为 5~ 7龄。该虫在林间以老熟幼虫的前 1龄幼虫 ,即以第 4~ 6龄幼虫越冬 ,其中以 5~ 6龄幼虫为主 ,4龄幼虫仅占少数  相似文献   

12.
1. Ontogenetic shifts in predator behaviour can affect the assessment of food‐web structure and the development of predator–prey models. Therefore, it is important to establish if the functional response and interference interactions differ between life‐stages. These hypotheses were tested by (i) comparing the functional response of second, third, fourth and fifth larval instars of Rhyacophila dorsalis, using three stream tanks with one Rhyacophila larva per tank and one of 10 prey densities between 20 and 200 larvae of Chironomus sp.; (ii) using other experiments to assess interference within instars (two to five larvae of the same instar per tank), and between pairs of different instars (one, two or three larvae per instar; total predator densities of two, four or six larvae per tank). 2. The first hypothesis was supported. The number of prey eaten by each instar increased with prey density, the relationship being described by a type II model. The curvilinear response was stronger for fourth and fifth instars than for second and third instars. Mean handling time did not change significantly with prey density, and increased with decreasing instar number from 169 s for fifth instars to 200 s for second instars. Attack rate decreased progressively with decreasing instar number. Handling time varied considerably for each predator–prey encounter, but was normally distributed for each predator instar. Variations in attack rate and handling time were related to differences in activity between instars, fourth and fifth instars being more active and aggressive than second and third instars, and having a higher food intake. 3. The second hypothesis was partially supported. In the interference experiments between larvae of the same instar or different instars, mean handling time did not change significantly with increasing predator density, and attack rate did not change for second and third instars but decreased curvilinearly for fourth and fifth instars. Interference between some instars could not be studied because insufficient second instars were available at the same time as fourth and fifth instars, and most third instars were eaten by fourth and fifth instars in the experiments. Prey capture always decreased with decreasing attack rate. Therefore, interference reduced prey consumption in fourth and fifth instars, but not in second and third instars. The varying feeding responses of different instars should be taken into account when assessing their role in predator–prey relationships in the field.  相似文献   

13.
Two non-cross-hybridizing cDNA clones were isolated from a lambda gt11 cDNA library prepared from Day 2 fifth instar female fat body of Manduca sexta and shown by hybrid selection to code respectively for the two storage proteins arylphorin and female-specific protein (FSP). Analysis of the developmental expression of arylphorin showed its presence during the feeding phases of the penultimate (fourth) and final (fifth) larval instars and its absence during the molt. Abdominal ligation of larvae followed by infusion of Grace's medium showed that this amino acid-rich medium was able to maintain arylphorin expression in fourth instar larvae, but not continued high expression in fifth instar larvae. This nutrient medium however was sufficient to allow initiation of expression in newly ecdysed fifth larval abdomens. Infusion of 5 micrograms 20-hydroxyecdysone (20HE) caused a significant reduction of arylphorin RNA in ligated fourth larval abdomens, whereas 50 micrograms was required in Day 2 fifth larval abdomens to suppress this RNA. Thus, both the lack of incoming nutrients and the rising titer of ecdysteroid contribute to the loss of arylphorin mRNA at the molts and at wandering. By contrast, FSP mRNA was first detected in females on Day 2 of the fifth instar, but not in males until wandering, and then was present throughout the prepupal period. In females allatectomy caused the precocious appearance of FSP mRNA which was prevented by application of 10 micrograms methoprene, a juvenile hormone analog. Expression of FSP mRNA in males however appeared to be independent of hormonal milieu.  相似文献   

14.
The parasitoidEucelatoria bryani Sabrosky regulates the larval behavior of its hostHelicoverpa zea (Boddie). Parasitized third, fourth and fifth instars burrow into the soil 0.7–3.4 days earlier than unparasitized larvae that normally enter the soil to pupate at the end of the fifth and final larval instar. Parasitized third instars molt once then burrow as fourth instars, one instar earlier than normal. WhenE. bryani pupariated on the soil surface in the field, none survived to the adult stage. However,E. bryani adults emerged from 49.2% of hosts that had burrowed into the soil. By accelerating the timing ofH. zea burrowing behavior and causing host larvae to enter the soil before death,E. bryani ensures its pupariation in an environment with improved protection against natural enemies and lethal temperatures.  相似文献   

15.
The increase in the juvenile hormone (JH) III titer in the hemolymph of Lymantria dispar larvae that were parasitized by the endoparasitoid braconid, Glyptapanteles liparidis, during the host's premolt to third instar, coincided with the molt of the parasitoid larvae to the second instar between day 5 and 7 of the fourth host instar. It reached a maximum mean value of 89 pmol/ml on day 7 of the fifth instar while it remained below 1 pmol/ml in unparasitized larvae. Only newly molted fifth instar hosts showed a low JH III titer similar to that of the unparasitized larvae. JH II, which is the predominant JH homologue in unparasitized gypsy moth larvae, also increased relative to controls in the last two samples (days 7 and 9) from parasitized fourth and fifth instars. Compared to unparasitized larvae, a generally reduced activity of JH esterase (JHE) was found in parasitized larvae throughout both larval stages. The reduction in enzyme activity at the beginning and at the end of each instar, when the JHE activity in unparasitized larvae was high, may be in part responsible for the increased JH II and JH III titers in parasitized larvae. Ester hydrolysis was the only pathway of JH metabolism in the hemolymph of unparasitized and parasitized gypsy moth larvae as detected by chromatographic assays. © 1996 Wiley-Liss, Inc.  相似文献   

16.
Virus yield produced by dead larvae of balsam fir sawfly, Neodiprion abietis (Harris) (Hymenoptera: Diprionidae), that had been infected at four different larval stages (second, third, fourth, or fifth instar) with two virus concentrations (10(5) polyhedral inclusion bodies (PIB) /ml or 10(7) PIB/ml), were analyzed and compared to determine the effects of instar and amount of virus inoculum on virus production. The results indicate that both larval stage and inoculation dosage significantly affect virus yield. On average, each dead larva produced 1.36-12.21 x 10(7) PIB, depending upon larval age and virus concentration of inoculation. Although each dead larva produced more PIB when it was inoculated in the fourth or fifth stage, inoculation of these larvae did not result in the highest virus yield because of low larval mortality. In terms of net virus return, third instars would maximize virus yield when they are inoculated with a virus concentration that can cause 95-100% larval mortality.  相似文献   

17.
《Journal of Asia》2020,23(1):60-66
The lepidopteran insect pests have significant importance in vegetable production. The present study was performed to investigate the baseline studies about the assessment of feeding and consumption potential, utilization indices and losses promises of leafworm, Spodoptera litura (Fab.) on Okra. The data regarding feeding potential, food utilization and consumption indices as well as losses of different larval instars were recorded and subjected to appropriate statistical analysis. The results showed that, in the beginning, the approximate digestibility of various instars was increase, e.g. third instar (51.36%–64.03%), fourth instar (63.42%–69.45%) and fifth instar (70.25%–76.10%). However, after a certain period, the digestibility was decreased and efficiency to convert the ingested food into biomass varied significantly. The consumption index values increased with an increase in time but the consumption and growth rate was declined of fourth instar larvae. The ingestion and digestion increased of third (10.01–13.06, 8.32–11.91 mg), fourth (11.27–17.28, 10.96–14.03 mg) and fifth (12.60–19.40, 11.93–15.28 mg) larval instars. The corrected weight of consumed leaves increased with a gain in body weight. However, in the third instar, a decline was observed on the last day of feeding. Maximum leaf area was consumed by fifth instar larvae (44.66 cm2) followed by fourth (35.41 cm2) and third (27.98 cm2) instars. In conclusion, all the dependent parameters, including food utilization potential, consumption indices and losses were higher for fifth instar larvae than others. These results emphasized the re-establishment of fundamental (economic threshold level: ETL, economic injury level: EIL) integrated pest management concepts.  相似文献   

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