赤拟谷盗PH_3抗性与CarE的关系研究

羧酸酯酶(Carboxylesterase,CarE)是昆虫体内代谢杀虫剂重要的水解酶之一。以重要储藏物害虫赤拟谷盗为供试对象,利用微量滴度酶标板法比较研究了PH3抗性与敏感品系成虫、幼虫、蛹阶段CarE的活力及动力学参数等生化指标。结果表明,各供试虫态中,赤拟谷盗各品系成虫期的CarE比活力均最高。与敏感品系相比,赤拟谷盗2个PH3抗性品系CarE的活力及比活力均低于敏感品系。进一步的动力学参数研究表明,各品系中,HSTC-R品系3个虫态的Km和Vmax值均最高,而HYTC-R品系的Km和Vmax值总体上也略高于敏感品系ABTC-S。Km在抗性品系中上升的事实表明CarE在抗性品系中结构发生了改变,这可能是该酶在抗性品系中水解能力下降的原因。     

金雀花碱等对小菜蛾幼虫体内羧酸酯酶等水解酶活性的影响

金雀花碱是多种植物的次生代谢物质。苦豆碱存在于豆科植物苦豆子中。以小菜蛾幼虫为供试对象研究表明,两种生物碱对昆虫体内的α－乙酸萘酯酶和α－乙酸萘酯羧酸酯酶活性有明显抑制作用,体内和体外试验表明了相似的结果,且抑制作用程度随各自生物碱浓度的增加而提高。     

Characterization of carboxylesterase PxαE8 and its role in multi-insecticide resistance in Plutella xylostella (L.)

Carboxylesterase (CarE) was considered as important phase-I detoxifying enzymes which participated in detoxification of different types of insecticides. Up-regulation of CarE genes has been proved playing a major role in insecticide resistance in many pest insects, but its involvement in resistance to insecticides in Plutella xylostella has been rarely reported. In this study, a CarE cDNA named PxαE8 was identified in P. xylostella, which has an open reading frame of 1 599 nucleotides and putatively encodes 532 amino acids. The investigation of spatial expression profiles of PxαE8 revealed that it was expressed in all developmental stages, especially in larvae and adults. The body part/tissue-specific expression profiles showed that the PxαE8 mainly expressed in fat body, malpighian tubule and hemolymph of larvae. Further, the relative expression of PxαE8 in two multi-resistant field populations, Hainan (HN) and Guangdong (GD) populations, was found 24.4- and 15.5-fold higher than that in susceptible population, respectively. Knockdown of PxαE8 by RNA interference dramatically increased the mortalities of larvae of HN population treated with LC₅₀ of beta-cypermethrin and phoxim by 25.3 and 18.3%, respectively. These results suggested that up-regulation of PxαE8 was involved in resistance to both beta-cypermethrin and phoxim in P. xylostella, which shed light on further understanding of molecular mechanisms of multi-insecticide-resistance in P. xylostella and other pest insects.     

砂地柏果实提取物对棉铃虫生长发育的影响

测定了新杀虫植物砂地柏果实的不同提取物对棉铃虫幼虫生长发育的影响,结果表明,砂地柏果实的不同提取物能明显抑制棉铃虫幼虫的生长发育速率;砂地柏果实不同提取物对供试幼虫体内羧酸酯酶活性的影响作用不同,甲醇提取物和石油醚回流物能不同程度激活羧酸酯酶活性,而甲醇回流物则对羧酸酯酶有抑制作用     

辐射对亚洲玉米螟体内几种水解酶活力的影响

研究了亚洲玉米螟Ｏｓｔｒｉｎｉａｆｕｒｎａｃａｌｉｓ（Ｇｕｅｎ．）不同虫成３－４龄幼虫、１－２ｄ龄蛹,当天羽化成虫）体内羧酸酯酶（ＣａｒＥ）、酸性磷酸酯酶（ＡＰ）和碱性磷酸酯酶（ＡｌＰ）的活力在不同＾６０Ｃｏγ辐照条件下的变化,结果表明,亚洲玉米螟不同虫态的ＣａｒＥ活力顺序为：幼虫     

枸杞木虱各虫期对三唑磷的敏感性及其与羧酸酯酶活力关系的研究

用浸渍法和药膜法分别测定了枸杞木虱若虫和成虫对三唑磷的敏感性,并测定了枸杞木虱各虫期羧酸酯酶的活性及三唑磷对其羧酸酯酶的抑制率。枸杞木虱各虫期对三唑磷的LC50随着龄期的增加而增加,各龄期的羧酸酯酶活性也随着龄期的增加而增加。三唑磷对各虫期羧酸酯酶的抑制率除3龄以外,也随着龄期的增加而增加,3龄期的抑制中浓度IC50较其他虫期为高。枸杞木虱羧酸酯酶活性越高,对农药的敏感性越低。     

家蚕血液羧酸酯酶活力影响因素研究初报

为了研究家蚕血液的羧酸酯酶活性变化规律,利用分光光度计法对家蚕血液中羧酸酯酶活性影响因素及在不同龄期的具体变化规律作了初步研究。结果表明:其最适温度为45℃;最适pH8.5;不同龄期的活性表现为各龄中期酶活力比较高,而在眠蚕、起蚕期酶活力相对较低,其中尤其以5龄第3、4天活力最高;在同一浓度下的杀虫剂对羧酸酯酶活性离体抑制作用实验中,敌百虫的抑制作用最强,乙酰甲胺磷次之,敌杀死最弱。     

田间小菜蛾抗药性监测及毒理机制研究

田间监测结果表明，福州地区小菜蛾Plutella xylostella(L.)已对生产上常用的各类杀虫剂产生不同程度的抗性，从9月至次年5年期间，田间小菜蛾表现出较高水平的抗性，而在8月份则表现出明显低的抗性水平，短期高温和长期低温的环境条件可明显抑制小菜蛾幼虫的AChE和CarE活性，但短期低温的环境条件对小菜蛾幼虫的AChE和CarE活性影响不大，饲养温度的变化不会影响小菜蛾幼虫AChE和Ki值，但在较高的酶与杀虫剂的反应温度下，有机磷对小菜蛾、菜青虫和黄曲条跳甲AChE的抑制作用显著增高，此外，探讨了田间影响小菜蛾抗性水平的环境因素及毒理学机制。     

Genomics-based approaches to screening carboxylesterase-like genes potentially involved in malathion resistance in oriental migratory locust (Locusta migratoria manilensis)

BACKGROUND: Previous studies have indicated that increased caboxylesterase (CarE) activity is a major mechanism of malathion resistance in field populations of the oriental migratory locust, Locusta migratoria manilensis (Meyen), in China. The aim of the present study was to screen CarE‐like genes from a large locust expressed sequence tag (EST) database and to assess their potential roles in malathion resistance. RESULTS: Twenty‐five ESTs derived from different CarE‐like genes in the locust EST database were identified, and 12 candidate genes with significantly increased expressions, ranging from 2.6‐ to 11.6‐fold in a field‐derived resistant (FR) colony of the locust, were found. These candidate genes were constitutively expressed in all nymph and adult stages, and most of them were predominantly expressed in the gastric caeca and the midgut. Among the 12 genes, two representative genes (LmCarE9 and LmCarE25) were chosen for RNAi followed by malathion bioassay. The nymph mortalities increased from 34.3 to 65.2 and 54.2% respectively after LmCarE9 and LmcarE25 were silenced. These results indicated significant roles of these CarE‐like genes in conferring malathion resistance in the locust. CONCLUSION: Multiple CarE‐like genes were involved in malathion resistance in the locust. As validated by RNAi followed by malathion bioassay, LmCarE9 and LmcarE25 played a significant role in conferring malathion resistance. Copyright © 2010 Society of Chemical Industry     

水稻品种抗性对白背稻虱羧酸酯酶和磷酸酶活力的影响

取食感虫品种的白背稻虱若虫体内羧酸酯酶(CarE)、酸性磷酸酶(AcpE)和碱性磷酸酶(AkpE)的活力明显高于取食抗虫品种的;取食中抗和中感品种的介于取食感虫品种和抗虫品种之间。水稻不同抗性品种对白背稻虱成虫及第二代若虫上述三种酶活力的影响也有类似倾向。