粘虫幼虫肠道蛋白水解酶特性的研究

本文研究了粘虫(Mythimna separata Walker)幼虫蛋白水解原酶和粗提的幼虫肠道蛋白水解酶的一些主要生化特性.实验结果表明:幼虫肠道蛋白水解酶温培后仍然保持最大酶活的最适温度是25℃,最适pH是11,从pH和酶活关系的曲线图可知原酶在pH9和10之间有一个“峰肩”,然而粗提酶则没有. 新鲜收集的幼虫原酶在30℃下经过2小时培养后,酶的活性可以提高10%.本研究也为寻找合适的粘虫幼虫蛋白水解酶的温度处理和作用条件提供了理论依据.     

利用超微量技术分析粘虫单腺体性信息素的化学组成

通过选择提取溶剂、改进提取方法以及毛细柱气相色谱检测条件,摸索出粘虫 Mythimna separata Walker单腺体提取和分析方法;并且确定了单个求偶雌蛾腺体提取物的化学组成、含量和相对比例。讨论了粘虫求偶雌蛾性信息素腺体提取物中各组分含量的个体差异。     

粘虫蛾飞行肌的发育：超微结构特征分析

应用电子显微镜对正常条件下饲养的0-16日龄粘虫Mythimna separata (Walker)雌蛾飞行肌超微结构的研究结果表明：肌原纤维直径。线粒体和横管的体积分量均随蛾龄的增加而增加,到7日龄达到最大值以后又随蛾龄的增加而下降;但是,肌节长度则随蛾龄的增加而缩短,到7日龄达到最短后又随蛾龄的增加而延长,从而使整条发育曲线呈“V”字形;肌原纤维和肌质网体积分量变化不大或无规律可寻;二位体在发育初期和未期的比例较高,而三位体在4和7口龄比例较高;肌丝排列从0～7日龄均是有序的,肌动蛋白丝(细丝)和肌球蛋白丝(粗丝)的数量比为3：1,粗丝的数量变化也不大,每根肌原纤维约有600根。但从10日龄开始肌丝排列出现紊乱,细丝全部消失,粗丝降解、数量减少了30%,从而使肌原纤维留下一片片的空白。根据这些结果,把7日龄前的飞行肌发育过程视为生长过程,而把10日龄后的视作降解过程。最后对粘虫蛾飞行肌与卵巢发育及其飞行能力变化的关系进行了讨论。     

Isolation of Sugar Compounds of Asparagine,Phenylalanine, Tyrosine and Valine from Cured Tobacco Leaves

Scanning electron microscopy and rigidity characterization were used in this study of myosin gelation in the presence of actin. The heat-induced gel formation of myosin was aided by the addition of actin to myosin at a molar ratio of 1: 2.7. However, this actin effect was not observed when the actin-binding site(s) of myosin was blocked by p-chloromercuri-benzoate treatment or denaturation, or when the myosin-binding site(s) of actin was blocked by trinitrophenylation.

The effect also disappeared with an aging myosin-actin mixture, with ATP or pyrophosphate as dissociating agent prior to thermal treatment of the system.

The present findings indicate the indispensability of myosin binding to actin for enhancing the thermal gelation of myosin. The gelation process appears to involve a large electrostatic contribution, as well as such chemical reactions as oxidation of SH groups.     

Differential host growth regulation by the solitary endoparasitoid, Meteorus pulchricornis in two hosts of greatly differing mass

Solitary koinobiont endoparasitoids generally reduce the growth of their hosts by a significant amount compared with healthy larvae. Here, we compared the development and host usage strategies of the solitary koinobiont endoparasitoid, Meteorus pulchricornis, when developing in larvae of a large host species (Mythimna separata) and a much smaller host species (Plutella xylostella). Caterpillars of M. separata were parasitized as L2 and P. xylostella as L3, when they weighed approximately 2 mg. The growth of parasitized M. separata larvae was reduced by almost 95% compared with controls, whereas parasitized P. xylostella larvae grew some 30% larger than controls. Still, adult wasps emerging from M. separata larvae were almost twice as large as wasps emerging from P. xylostella larvae, had larger egg loads after 5 days and produced more progeny. Survival to eclosion was also higher on M. separata than on P. xylostella, although parasitoids developed significantly faster when developing on P. xylostella. Our results provide evidence that koinobionts are able to differentially regulate the growth of different host species. However, there are clearly also limitations in the ability of parasitoids to regulate phenotypic host traits when size differences between different host species are as extreme as demonstrated here.     

Reproductive biology of the microtype tachinid fly Zenillia dolosa (Meigen) (Diptera: Tachinidae)

Reproductive biology including mating, adult longevity, fecundity and development of the tachinid fly Zenillia dolosa was investigated for optimizing rearing procedures using Mythimna separata as a host in the laboratory. Females lay microtype eggs containing a first instar larva on food plants of the host and then the eggs must be ingested by the host for parasitization. Mating success was 58.5% with mating duration of 80.7 min. Mating was most successful when day 0–1 females were kept with day 2–4 male flies. Female body size was positively correlated with its fecundity but not with longevity. However, females that survived longer produced more eggs during their lifetime. Parasitoids successfully developed in 4th to 6th instar host larvae. Host instars at the time of parasitoid egg ingestion significantly influenced development time of the immature parasitoid, but did not affect body size of the emerging parasitoid. We suggest that pairing newly emerged females with day 2–4 males should result in higher mating success and using the last instar hosts for parasitization should minimize development time of the parasitoid for rearing.     

Temperature-sensitive eye colour mutation in the parasitoid fly Exorista japonica Townsend (Dipt.: Tachinidae)

Abstract:  An eye colour mutation was found in the tachinid fly Exorista japonica Townsend, and we established an isogenic line of the mutant. The phenotype of the mutant is red eye in adults; this can be clearly distinguished from the brown-eyed phenotype of the wild type. Crossing experiments demonstrated that the mutant phenotype is controlled by a single autosomal recessive allele. As rearing temperature during the puparial stage rose, eye colour became lighter in the mutant but did not change in the wild type, indicating that the phenotype of the mutant is temperature dependent. No differences in the percentages of egg eclosion, pupariation and adult emergence were observed between the mutant and the wild type. This mutant of E. japonica – the first in the Tachinidae to be described – could be a useful marker in the laboratory experiments to test for paternity in multiple mating and to examine intraspecific competition.     

Biological activity and identification of nucleopolyhedroviruses isolated from <Emphasis Type="Italic">Mythimna separata</Emphasis> and <Emphasis Type="Italic">Spodoptera litura</Emphasis> in Japan

We compared the infectivity of two nucleopolyhedroviruses (NPVs), MyseNPV G isolated from Mythimna separata (Walker) (Lepidoptera: Noctuidae) and SpltNPV S isolated from Spodoptera litura (Fabricius) (Lepidoptera: Noctuidae). MyseNPV G was more pathogenic against M. separata than against S. litura. Although SpltNPV S was more pathogenic than MyseNPV G against S. litura, it did not infect M. separata. Restriction endonuclease (REN) analysis of viral genomic DNA revealed that the two NPVs have quite different REN profiles. Based on nucleotide sequences of the coding regions of polyhedrin, lef-8 and lef-9, SpltNPV S was closely related to other SpltNPV isolates, whereas MyseNPV G appeared to belong to the Mamestra NPV group, and was distinct from a Chinese isolate of Leucania (=Mythimna) separata NPV. The potential of MyseNPV G and SpltNPV S to control pest insects is discussed.

{[1-(Arylmethyl)piperidin-4-yl]oxy}-(trifluoromethyl)-pyridines: ketanserin analogues with insect growth regulating activity

A series of {[1-(arylmethyl)piperidin-4-yl]oxy}-(trifluoromethyl)-pyridine derivatives were designed and synthesized on the basis of the ketanserin (1) framework, a prototypic mammalian 5-HT(2A) receptor antagonist, and the structure-activity relationship (SAR) was also discussed. The result of the bioassay showed that most of the title compounds inhibited the insect growth and exhibited moderate-to-good growth regulating activity against the armyworm Pseudaletia separata Walker. Furthermore, the SAR study revealed that, when the determinant feature, interacting with mammalian 5-HT(2A) receptor, was preserved, a simplified ArCH(2) group greatly contributed to insect growth inhibitory activities. It was also found that the substituted position of the CF(3) group at the pyridine ring played a key role, and that the introduction of 1-[bis(4-fluorophenyl)methyl]piperazine, an equivalent of the benzoylpiperidine moiety of ketanserin, resulted in bioactivities similar to those of the title compounds, which were in agreement with the model of ketanserin analogues binding to mammalian 5-HT(2) receptors.     

粘虫的年龄—发育期结构生命表

在23℃下用玉米嫩叶饲养幼虫,组建了粘虫的年龄-发育期结构生命表。这种生命表考虑到种群内个体发育进度的差异并包括雄性成虫。根据生命表资料计算的粘虫种群主要参数是：净繁殖率R_O= l55.88,内禀增长率r_m=0.1120,平均世代长度T=45.08天。讨论了年龄-发育期结沟生命表方法和传绕生命表方法的主要差别及各自的优缺点,比较了用这两种方法得到的粘虫种群的主要参数值。