染色质重塑及其参与植物病害防御应答的研究进展

转录相关因子与特异DNA位点结合受染色质空间构象变化的调节,通过染色质重塑机制可以解除染色质高度紧密的折叠状态,改变组蛋白与DNA链间的作用力,控制基因的表达与沉默。ATP依赖的染色质重塑复合物、组蛋白的乙酰化/去乙酰化和甲基化/去甲基化共价修饰等是染色质修饰的主要类型,植物能通过染色质重塑复合物和组蛋白修饰酶复合物直接或间接介导的染色质重塑作用调控防御基因的转录,控制植物对病原体侵染的防御应答。本文结合近年来的研究进展,对植物染色质重塑如何调控防御相关基因的表达及病原体蛋白T3SEs、6b和VirE等如何利用染色质重塑干预植物防御系统的分子机制进行了论述。     

温度胁迫下昆虫表观遗传机制的研究进展

温度是限制物种适应性分布的重要因子，决定着物种的分布和扩散区域。昆虫作为小型变温动物，对温度变化十分敏感，温度胁迫反应是其抵御极端环境的最保守的机制之一。其中表观遗传学为昆虫提供了更快的温度胁迫响应机制，与经典遗传学不同，表观遗传学在不改变DNA序列的前提下响应环境变化对基因表达产生快速而持久的影响。表观遗传调控包括DNA甲基化、组蛋白修饰、染色质重塑、非编码RNA调控等，本文主要阐述了以上四个方面在昆虫响应温度胁迫中的应用和研究进展，以探究昆虫在温度变化中的适应能力。     

组蛋白修饰调控植物水杨酸信号转导的研究进展

真核生物中组蛋白翻译后共价修饰直接影响染色质空间结构变化,调控相关基因表达,在植物胁迫应答过程中起重要作用。水杨酸(salicylic acid,SA)作为植物中关键信号分子,诱导多种病毒、真菌及细菌病害抗性。本文简要介绍了植物细胞对病原菌的感知、转导信号产生与防御系统激活机制,着重阐述了组蛋白甲基化、乙酰化、SUMO化修饰、组蛋白变体H2A.Z等如何参与调控水杨酸转导途径应答基因的转录表达。     

m6A RNA甲基化修饰在昆虫生长发育、免疫和抗药性中的作用

N6-腺苷酸甲基化(N6-methyladenosine, m6A)修饰是真核生物中含量最丰富的RNA修饰, 通过参与RNA的选择性剪接、稳定性、出核、翻译和降解等分子过程从而调控动物、植物和微生物的多项重要生物学功能。本文总结归纳了m6A 修饰在果蝇Drosophila、家蚕Bombyx mori、意大利蜜蜂Apis mellifera和烟粉虱Bemisia tabaci等昆虫生长发育、免疫和抗药性中的作用, 并分析了当前研究中的不足与空白, 为进一步研究m6A修饰在昆虫中的生理功能提供参考。     

禾谷镰刀菌组蛋白乙酰转移酶FgHat1在DON毒素生物合成中的功能

 由禾谷镰刀菌引起的小麦赤霉病是小麦最主要的真菌病害之一。禾谷镰刀菌侵染小麦时分泌脱氧雪腐镰刀菌烯醇(DON)真菌毒素,威胁人畜健康。本研究通过对组蛋白乙酰转移酶基因FgHAT1的功能研究,发现该基因编码的蛋白定位于细胞核并调控组蛋白H4的乙酰化。Fghat1敲除突变体在生长发育和致病过程中表现正常,但毒素合成存在显著缺陷。敲除FgHATI导致参与DON毒素合成的TRI基因转录水平降低,突变体产毒相关的细胞分化也表现异常。外源添加cAMP可以有效回复突变体的产毒缺陷,表明FgHat1对毒素的调控与cAMP信号通路有关。研究结果表明组蛋白表观修饰和胞内信号通路之间存在联系,这两者的交叉互作对DON毒素合成的精确调控至关重要。     

改造病毒基因组增强病毒杀虫剂杀虫效率研究进展

由于基因工程技术的发展和安全性研究的深入,以重组杆状病毒为主的重组昆虫病毒杀虫剂的应用正面临着突破。文章综述了通过修饰或删除昆虫病毒某些基因、插入控制宿主发育、代谢激素或酶的基因、删除、修饰昆虫病毒基因组中特定的基因以扩大宿主域、应用RNA干扰技术提高昆虫病毒杀虫效率等构建重组昆虫病毒杀虫剂的技术路线,展望重组病毒杀虫剂的发展趋势。     

昆虫翅发育研究的现状与前景

翅的形成有利于昆虫的迁移,一些害虫依靠强大的飞行能力扩散为害,致使农林业产业经济损失严重。目前,昆虫翅发育研究在遗传调控机理方面取得了大量突破性进展,作为生物器官的研究模型,昆虫翅为生物医学提供了良好的范本。为深入了解昆虫翅发育的研究进展和在植物保护及生物医学领域中的应用,本文介绍了昆虫翅发育的普遍调控机理,对比了不同变态发育类型代表性昆虫的翅发育关键调控基因及其作用机理,并结合最新涌现的RNA农药、纳米材料转染生物分子、基因编辑等技术,分析并展望了农业害虫防治中的翅模型研究的应用前景。     

昆虫激脂激素的功能及作用机制研究进展

激脂激素（adipokinetic hormone,AKH）是昆虫体内调节能量稳态的重要内分泌神经多肽,能够促进脂肪体中营养储存物质的分解,在维持昆虫高耗能生命活动中具有关键作用。AKH的研究在早期多围绕昆虫飞行及爬行等运动活动中促进甘油三酯、糖元等物质分解的功能和信号传导机制。近年来的研究发现,AKH/膜受体AKHR通路也参与促进卵黄发生和后代哺育过程中营养物质的调动。另外,AKH在抗氧化、忍耐饥饿和免疫等逆境响应中的稳态维持也具有重要作用。越来越多的研究证明,作为重要的能量物质动用激素,AKH是一种参与多种生理活动的多效性调控因子。本文就AKH/AKHR信号通路在昆虫运动、生殖及抗胁迫等生理活动中功能和作用机制的研究进展进行总结和论述,以期为进一步阐明AKH在昆虫能量稳态调控中的分子机制提供帮助,并为解析害虫远距离迁飞、大量繁殖以及抗环境胁迫的分子基础和遗传调控机理提供参考。     

昆虫神经肽抑咽侧体素及其类似物的研究进展

抑咽侧体素 (ASTs) 是一类由昆虫脑神经细胞分泌，通过作用于咽侧体进而抑制保幼激素 (JH) 合成与释放的昆虫神经肽。因其具有调控昆虫生长、发育和生殖等生理过程的功能，被认为是一类潜在的害虫控制剂。本文在简介了昆虫神经肽在害虫防治中的应用基础上，综述了昆虫神经肽抑咽侧体素的发现、类别和功能，并结合本研究组的工作，重点介绍抑咽侧体素及其类似物的结构修饰和优化、活性构象及构效关系研究，同时也介绍了抑咽侧体素及其类似物的受体和作用机制研究进展。最后，展望了该领域的未来发展趋势，期望为新的生态友好型农药的研发提供一定的参考作用。     

果蝇免疫基因的表达

昆虫与高等动物不同，没有B和T淋巴细胞系统，即便是它的体液因子也无免疫球蛋白存在。昆虫虽然没有完善的免疫体系，但它们先天性或获得性免疫能力却是惊人的。许多昆虫（蝗虫、蜚联、蝇、蚕等）都具有很强的抗病力’“。借助于现代分子生物学技术，人们开始研究其独特的免疫机理。第一个昆虫免疫基因（cecroPin）从鳞翅目昆虫天蚕opinfothe？．一田好的m）中克隆到后”’，双翅目昆虫果蝇（除规…伽）中也克隆到类似基因，现已从昆虫免疫机制研究的模式种一果蝇O沈叨…砌M勿my白河）中克隆10个免疫反应基因。本文对果蝇免疫反应基因的结…     

昆虫氨肽酶N的研究进展

氨肽酶N(aminopeptidase N,APN)是一种偏好水解蛋白或寡肽N端中性氨基酸的酶,广泛分布于动植物中。在昆虫中,APN主要分布于中肠刷状缘膜上,涉及食物蛋白的消化以及Bt毒素对靶标害虫的作用。从APN的结构特征和分类地位、APN的分离纯化及其酶活性位点与结合位点的相关性、APN同工酶的区分特征及系统发育关系、APN同工酶的基因功能、不同APN同工酶在昆虫体内的分布及表达量、APN基因功能最新研究方法和结果以及APN与昆虫抗药性的关系等方面概述了昆虫APN的最新研究进展。鉴于昆虫体内受体的多样性、复杂性及当前研究手段的局限性,对APN功能的全面了解还有赖于研究方法的改进和提高而逐步深入。     

高通量测序技术在害虫和害螨抗药性研究中的应用

螨类是陆生动物中仅次于昆虫的第2大类群。长期以来,对害螨抗药性的研究都落后于害虫。近年来,随着高通量测序技术的出现,开辟了害虫和害螨抗性机理研究和抗性监测的新局面。本文概述了高通量测序技术应用于害虫和害螨抗药性机理研究已取得的进展,介绍了利用高通量测序技术开发的抗药性监测新方法,并提出了害虫和害螨抗药性机理研究和田间种群抗性水平监测的发展方向。     

Photometric determination of methyl parathion GSH S-methyl transferase

Two methods are described for the assay of the enzyme that transfers a methyl group from methyl parathion (O,O-dimethyl-O, p-nitrophenyl phosphorothionate) to glutathione. A colorimetric assay depends on the measurement of alkali-soluble, chloroform-insoluble aromatic nitro compounds in the reaction mixture and a more rapid and sensitive direct spectrophotometric assay is described that uses the double wavelength Perkin-Elmer 356 Spectrophotometer. The utility of both methods has been demonstrated by the measurement of some kinetic constants and the distribution of the enzyme among some insects and vertebrates.     

Insecticide toxicity and synergism by enzyme inhibitors in 18 species of pest insect and natural enemies in crucifer vegetable crops

The toxicities of three enzyme inhibitors and their synergistic effects on four insecticides were studied by using the dry film method on field populations of 18 species of insects collected in Jianxin and Shanjie, China, from 2003 to 2005. Meanwhile, the inhibitory effects of these enzyme inhibitors on the activities of acetylcholinesterases (AChE), carboxyesterases (CarE) and glutathione-S-transferases (GST), in vivo, were also studied. In general, triphenyl phosphate (TPP) and diethyl maleate (DEM) showed low toxicities to six herbivorous pest insects, four ladybirds and eight parasitoids. Piperonyl butoxide (PB) exhibited low toxicities to the herbivorous pest insects and ladybirds, but high toxicities to the eight parasitoids. The tolerance to the insecticides in 11 pest insects and natural enemies was mainly associated with the tolerance to PB. PB showed the highest synergism on methamidophos, fenvalerate, fipronil and avermectin in nine species of pest insects and natural enemies. In general, TPP and DEM showed significant synergisms to these four insecticides in four parasitoid species. However, in contrast to their effects on the parasitoids, the synergistic effects of TPP and DEM on the four insecticides by TPP and DEM against four pest insects and one ladybird varied depending on the insect species and enzyme inhibitor. Activity of AChE, CarE or GST could be strongly inhibited, in vivo, by PB, TPP or DEM, depending on the insect species and enzyme inhibitors. From the results obtained in this study, mixed-function oxidase (MFO) was thought to play the most critical role in insect tolerances to the tested insecticides in the field. Low competition existed in the evolution of insecticide resistance in the field populations of parasitoids, as compared with herbivorous pest insects and ladybirds. Possible causes of the high synergistic effects of PB on the four classes of insecticides, based on multiattack on the activity of CarE, GST or AChE in the insect species, are also discussed.     

基于多重PCR技术的高通量测序在植食性昆虫食谱鉴定中的潜在应用

多重PCR技术因成本低、灵敏度高、快捷、高效等优点而被广泛用于遗传病鉴定和传染病传播、食品掺假、污染鉴定以及病虫害检测中,但多重PCR技术在动植物分类中应用较少,在植食性昆虫食谱鉴定中应用更少。该文详细介绍了植食性昆虫食谱分子鉴别技术,多重PCR技术要素、种类和应用以及与其他技术的结合应用,高通量测序中多重PCR捕获技术,并对多重PCR技术与高通量测序技术的结合在动物食谱鉴定中的潜在应用进行了展望。     

Microsomal oxidase activities in relation to age and chlorcyclizine induction in American cockroach,Periplaneta americana,fat body,midgut and hindgut

Female adult American cockroaches, Periplaneta americana L., showed definite age-dependent changes in levels of activity of the microsomal mixed-function oxidases. Cytochrome P-450 levels, EPN-detoxication, and p-nitroanisole O-demethylation activities were very low in young adult insects but increased steadily reaching a natural peak at about 100 days in fat body and at about 90 days in midgut and hindgut. The activities then declined rapidly reaching levels of young insects at about 130 to 140 days of age. NADPH-neotetrazolium-reductase activity was high in young insects, declined later in adult life, and returned to a peak at about 100 days.Injections of chlorcyclizine, a known microsomal enzyme inducer, significantly increased levels of cytochrome P-450, EPN-detoxication, p-nitroanisole O-demethylation, and NADPH-NT-reductase activities in young cockroaches. The drug injections were effective, however, only before the natural activity peak was reached. Beyond this point the injections had no inductive effect indicating that the microsomal oxidases in this insect are uninducible when normal enzyme levels are falling.NADPH-NT-reductase activity in male cockroaches, while being somewhat higher than in females, showed a similar age-dependent curve with the peak occurring at about 120 days.Age-dependent carbaryl resistance in male and female insects tended to follow levels of the microsomal oxidase activities. Fifty to 60-day-old insects, however, tended to be more resistant to the insecticide than microsomal enzyme levels would indicate.RNA levels of normal female insects showed age-dependent curves similar to those of the microsomal enzyme activities, being low in young adults and reaching a peak at about 100 days. Chlorcyclizine injections had little or no effect on total microsomal RNA levels.