鳞翅目昆虫精巢融合的研究

昆虫精巢是产生精子并为精子发育提供营养和保护的重要器官．昆虫雄虫在幼虫期通常有左右对称的２个精巢．但是,部分昆虫如农业害虫斜纹夜蛾在从幼虫向蛹变态发育的过程中,２个精巢发生融合,合二为一,在蛹期最终完全融合成单个精巢;有些昆虫如经济昆虫家蚕的２个精巢并不融合,在成虫期仍保持分离．精巢融合显然是昆虫长期自然演化过程中形成的一种繁殖方式,有利于种群的繁殖和扩大．本文结合课题组的研究,对鳞翅目昆虫精巢的类型和结构、精子产生的过程、精巢融合的现象及其生物学意义以及在农业害虫防治上的潜在应用意义进行了简述．     

斜纹夜蛾几丁质酶家族基因鉴定与时空表达分析

昆虫GH18家族几丁质酶属于多基因家族,在昆虫的蜕皮与变态过程中发挥着至关重要的作用,它催化表皮几丁质的降解.斜纹夜蛾是一种重要的农业害虫,危害290多种植物,但对其几丁质酶未深入研究.该文通过斜纹夜蛾转录组学分析,发现了12种潜在的几丁质酶,分属于8类.对这些几丁质酶在斜纹夜蛾变态发育时在表皮、中肠以及脂肪体的时空表达分析结果表明,Sl Cht5,Sl Cht9和Sl Cht2的表达水平在幼虫转化为蛹时上调表达,说明这些几丁质酶可能参与了斜纹夜蛾变态时期的脱皮作用;而其他几丁质酶的表达具有组织特性,表明它们可能具有不同功能,如Sl Cht6仅在中肠和脂肪体中表达,Sl Cht11,Sl Cht12和Sl Cht16主要在中肠和表皮表达,Sl IDGF2仅在表皮有表达,Sl IDGF3和Sl Cht9在三大组织均有表达.本研究结果对斜纹夜蛾几丁质酶家族基因的鉴定和时空表达作了初步的分析,为研究它们在斜纹夜蛾发育中的功能与调控打下基础.     

Expression of a polypeptide containing a dipeptide repeat is confined to the insect stage of Trypanosoma brucei

The protozoan parasite Trypanosoma brucei is transmitted between mammalian hosts by the tsetse fly (Glossina spp.). Trypanosomes ingested by the fly undergo a number of changes in the insect midgut during differentiation to procyclic forms. These include the loss of the variant specific glycoprotein (VSG) coat and the appearance of a common set of procyclic surface antigens. In order to investigate genes other than VSG genes which are expressed only at certain stages of the life cycle, the first cDNA specific to procyclic culture form trypanosomes (equivalent to the stage found in the insect midgut) has been characterized. The encoded polypeptide shows several characteristics of membrane proteins, but its most striking feature is the presence of a repetitive amino-acid sequence in which there are 22 tandem repeats of the dipeptide-Glu-Pro-. Related genes are also found in other trypanosome species and in leishmania. This gene shows many similarities to a number of surface antigen genes described in malaria and, more recently, Trypanosoma cruzi. This is the first example of a repetitive sequence in a parasite protein which is present only in the insect vector, and which therefore cannot be implicated in the mammalian host immune response.     

鲍幼虫变态分子机制的研究进展

综述了鲍幼虫变态及其分子机制的研究进展.鲍因其幼虫营卵黄营养,且同昆虫和蛙类相比,鲍幼虫变态速度快、存在提早发育(‘anticipatory’developmental program)现象,是研究贝类乃至海洋无脊椎动物变态现象的理想模式.早期研究采用药理学和电生理学方法发现了GABA等能够诱导鲍变态的物质,并且提出了变态过程信号通路,但调节幼虫变态的分子机制仍然所知甚少.研究人员采用差异显示PCR和基因芯片等手段获得了一些变态前后差异表达的基因.但是变态是由众多的基因和信号分子共同决定和影响的.传统获得差异基因的方法效率低、获得基因数量少、受公布的EST(表达序列标签)限制大,所以调控变态的分子网络和机制还尚未建立,缺乏对调控这一细胞过程的整体认识.转录组学分析获得大量变态差异基因,并且有助于建立差异基因相互作用网络,是研究变态分子机制的新方向.此外,变态差异基因的功能验证和注释是鲍变态分子机制研究的另一问题,基因干扰可能是解决方向之一.     

湘西地区军事本草植物资源研究（Ⅲ）——治疗蛇虫伤害植物资源调查分析

为了解湘西地区治疗蛇虫伤害植物资源，构建军事治疗蛇虫伤害植物本草资源库，采用实地取样调查并结合文献查阅等方法，对湘西地区治疗蛇虫伤害的军事本草资源进行综合性分析.结果表明：湘西地区治疗蛇虫伤害的植物共284种，隶属94科207属，生活习性以草本为主，生境以林中为主；水平分布北部比南部丰富，垂直分布随海拔升高呈现先增加后减少的趋势，其中600~1 299 m海拔范围内分布最多；区系地理成分复杂多样，科以世界分布和泛热带分布为主，属以泛热带分布和北温带分布为主，种以东亚分布、中国特有分布和热带亚洲分布为主；药用部位以全草可药用植物居多，用药方法多样，主要为外用取适量鲜品捣烂敷患处、内服取适量煎汤服用.当前湘西地区治疗蛇虫伤害植物资源丰富，但开发利用程度低，应在可持续利用的范围内加强研究和开发.     

A monoclonal antibody specific for diploid epithelial cells in Drosophila

Results from various experiments suggest that the cell surface has an important role in development. However, there is relatively little information on the specific surface molecules involved in developmental processes. In an effort to characterize cell-surface components that may be involved in Drosophila development, we have been making monoclonal antibodies against D. melanogaster imaginal disks. The holometabolous insects are unusual in that scattered among the larval tissues are groups of undifferentiated imaginal cells which, during metamorphosis, will form most of the adult insect. The imaginal disks, which we use as an immunogen, are hollow sacs of cells; each disk will form a specific part of the adult cuticle. Other imaginal cells are found as nests or rings in various larval organs. We describe here results indicating that one of the clones we have isolated, DA.1B6, makes an antibody against an antigen which, in larvae, is generally restricted to the undifferentiated sheets of imaginal epithelial cells. This and other results indicate that the antigen is specific for the diploid epithelia in Drosophila.     

花背蟾蜍内胚层细胞核在核移植胚胎LDH表达上的等能性

研究了花背蟾蜍发育不同阶段内胚层细胞核为供体的核移植胚胎的LDH同工酶。发育20期之前的核移植胚胎整体的LDH同工酶谱均与发育同期正常受精的胚胎结果一致。发育20期之后,分别取肝、鳃、脑及肠进行分析,核移植胚胎的LDH同工酶表现也与对照组基本一致,表明花背蟾蜍早期发育不同阶段的内胚层细胞核在核移植胚胎LDH同工酶表达上具有全能性。     

广州市春夏季尸食性昆虫群落种类组成与演替

 对广州地区家兔尸体的腐败过程及尸体上昆虫群落的演替规律, 进行了初步观察和研究。结果表明, 室外地表上家兔尸体的腐败过程可以划分为新鲜、肿胀、腐烂、干化4个连续的阶段; 常见昆虫包括3 目、12 科、20 种, 其中双翅目的大头金蝇、绯颜裸金蝇,鞘翅目的大隐翅虫、白腹皮蠹等为优势种。尸体上昆虫群落的演替有明显的时间规律可循。许多昆虫类群的出现时间与尸体腐败阶段有明确的对应关系, 这种对应关系可以为法医科学中推测死后间隔时间(postmortem interval, PMI) 提供依据。     

沈阳大学北校区主要绿化树种害虫的调查

为了给沈阳大学师生员工创造一个优越的校园绿化环境,笔者调查了沈阳大学北校区校园绿化种植的树种及其树种害虫的种类、危害部位和危害程度.结果表明,其校园内树种害虫种类从类别上看隶属于2纲7目26科,共43种.在调查分类的基础上,根据校园特殊的区位环境,提出了沈阳大学北校区绿化树种害虫的物理、生态和化学防治建议,并应以生态防治为主要方向.     

北极及长白山苔原带昆虫多样性研究进展

苔原是冷湿型极地自然景观类型,全世界现代苔原仅分布于北半球.综述北极苔原带昆虫的物种组成:部分苔原带种类存在较明显的形态适应,北极苔原带温度和紫外线对昆虫有较大影响,较低温度和较短的生长季节是导致昆虫多样性较低和形态变化的主要原因,当温度升高时昆虫能快速扩散到北极苔原带;综述长白山苔原带昆虫种类组成,侵入种及侵入原因,直翅目蝗虫种群适应变化和天牛、食蚜蝇、蝶类访花昆虫种类及其访花习性等研究进展.     

Host specificity of Lepidoptera in tropical and temperate forests

For numerous taxa, species richness is much higher in tropical than in temperate zone habitats. A major challenge in community ecology and evolutionary biogeography is to reveal the mechanisms underlying these differences. For herbivorous insects, one such mechanism leading to an increased number of species in a given locale could be increased ecological specialization, resulting in a greater proportion of insect species occupying narrow niches within a community. We tested this hypothesis by comparing host specialization in larval Lepidoptera (moths and butterflies) at eight different New World forest sites ranging in latitude from 15 degrees S to 55 degrees N. Here we show that larval diets of tropical Lepidoptera are more specialized than those of their temperate forest counterparts: tropical species on average feed on fewer plant species, genera and families than do temperate caterpillars. This result holds true whether calculated per lepidopteran family or for a caterpillar assemblage as a whole. As a result, there is greater turnover in caterpillar species composition (greater beta diversity) between tree species in tropical faunas than in temperate faunas. We suggest that greater specialization in tropical faunas is the result of differences in trophic interactions; for example, there are more distinct plant secondary chemical profiles from one tree species to the next in tropical forests than in temperate forests as well as more diverse and chronic pressures from natural enemy communities.     

A natural polymorphism alters odour and DEET sensitivity in an insect odorant receptor

Blood-feeding insects such as mosquitoes are efficient vectors of human infectious diseases because they are strongly attracted by body heat, carbon dioxide and odours produced by their vertebrate hosts. Insect repellents containing DEET (N,N-diethyl-meta-toluamide) are highly effective, but the mechanism by which this chemical wards off biting insects remains controversial despite decades of investigation. DEET seems to act both at close range as a contact chemorepellent, by affecting insect gustatory receptors, and at long range, by affecting the olfactory system. Two opposing mechanisms for the observed behavioural effects of DEET in the gas phase have been proposed: that DEET interferes with the olfactory system to block host odour recognition and that DEET actively repels insects by activating olfactory neurons that elicit avoidance behaviour. Here we show that DEET functions as a modulator of the odour-gated ion channel formed by the insect odorant receptor complex. The functional insect odorant receptor complex consists of a common co-receptor, ORCO (ref. 15) (formerly called OR83B; ref. 16), and one or more variable odorant receptor subunits that confer odour selectivity. DEET acts on this complex to potentiate or inhibit odour-evoked activity or to inhibit odour-evoked suppression of spontaneous activity. This modulation depends on the specific odorant receptor and the concentration and identity of the odour ligand. We identify a single amino-acid polymorphism in the second transmembrane domain of receptor OR59B in a Drosophila melanogaster strain from Brazil that renders OR59B insensitive to inhibition by the odour ligand and modulation by DEET. Our data indicate that natural variation can modify the sensitivity of an odour-specific insect odorant receptor to odour ligands and DEET. Furthermore, they support the hypothesis that DEET acts as a molecular 'confusant' that scrambles the insect odour code, and provide a compelling explanation for the broad-spectrum efficacy of DEET against multiple insect species.     

Adaptive visual metamorphosis in a deep-sea hydrothermal vent crab

Hydrothermal vents along the mid-ocean ridges host ephemeral ecosystems of diverse endemic fauna including several crustacean species, some of which undergo planktonic development as larvae up to 1,000 m above and 100 km away from the vents. Little is known about the role of vision in the life history of vent fauna. Here we report that planktonic zoea larvae of the vent crab Bythograea thermydron possess image-forming compound eyes with a visual pigment sensitive to the blue light of mesopelagic waters. As they metamorphose and begin to descend to and settle at the vents, they lose their image-forming optics and develop high-sensitivity naked-retina eyes. The spectral absorbance of the visual pigment in these eyes shifts towards longer wavelengths from larva to postlarva to adult. This progressive visual metamorphosis trades imaging for increased sensitivity, and changes spectral sensitivity from the blue wavelengths of the larval environment towards the dim, longer wavelengths produced in the deeper bathypelagic vent environment of the adults. As hydrothermal vents produce light, vision may supplement thermal and chemical senses to orient postlarval settlement at vent sites.     

缙云山森林生态系统物种多样性空间格局分析

通过对缙云山森林生态系统各发展阶段永久性样地的调查研究，初步揭示森林生态系统发展过程物种多样性空间格局变化规律，发现乔木层物种丰富度和总多样性基本随系统局长的方向逐渐增大，但其过程存在着波动变化，物种均匀变化与系统发展方向关系不大，灌木层和草本层物种多样性变化与群落郁闭度相关。     

海洋底栖动物浮游幼体附着和变态的研究

海洋底栖动物浮游幼体附着和变态的研究具重要的理论和应用价值．我校海洋系在国内较早开展该领域的研究，近10年来，取得了系列研究成果，促进了我国在海洋底栖动物幼体附着和变态研究领域的发展．所研究的海洋底栖动物有翡翠贻贝（Vegna viridis）、僧帽牡蛎（Saccostrea cucullata）、盘鲍（Haliotis discus discus）、杂色鲍（Haliotis diversicolor）、华贵栉孔扇贝（Chlamys nobilis）、台湾东风螺（Babylonia formosae）、方斑东风螺（B．areolata）、冠瘤海鞘（Styela canopus）和白脊藤壶（Balanus albicostatas）．研究内容包括幼体附着和变态过程中的幼体行为学和形态学观察、幼体附着和变态的影响因子、机制及应用研究．     

新型杀虫剂的作用机制和选择毒性

作用机制的研究对于开发新型害虫防治药剂是非常重要的。本文综述了一系列具有新颖作用机制的新型杀虫剂,包括神经毒性杀虫剂、昆虫生长调节剂、几丁质合成抑制剂以及作用于氧化磷酸化的杀虫剂,并讨论了它们对非靶标生物的选择毒性。