昆虫嗅觉神经的计算机三维重建

基于激光扫描共聚焦显微镜平台的计算机三维重建在昆虫嗅觉神经研究中发挥了重要作用。对经荧光标记的神经组织采集系列光学切片并进行三维重建,在双翅目、鳞翅目、膜翅目、蜚蠊目昆虫中均有进展。触角叶是昆虫的初级嗅觉中心,触角叶的解剖学图谱是识别不同种和雌雄虫间嗅球体特定功能的先决条件。了解构成嗅觉传输途径的主要神经元的形态和空间关系是理解气味信息在中枢神经系统编码的基础。三维重建昆虫的嗅觉神经,对于探讨昆虫嗅觉在其寄主选择、觅食以及寻找配偶等行为中的作用具有非常重要的意义。     

Antennal sensilla and their nerve innervation in first‐instar nymphs of Porphyrophora sophorae Arch. (Hemiptera: Coccomorpha: Margarodidae)

ABSTRACT Porphyrophora (Hemiptera: Coccomorpha: Margarodidae) is a genus of soil‐inhabiting scale insects. The antennal sensilla and their innervation in the first‐instar nymphs of Porphyrophora sophorae were studied using light microscopy and scanning and transmission electron microscopy to understand the function of these sensilla and determine the sensillar innervation feature on these small antennae. The results show that the six‐segmented antennae of these nymphs have 20–23 sensilla which can be morphologically classified into seven types, for example, one Böhm's bristle (Bb), one campaniform sensillum (Ca), one Johnston's organ (Jo), 13–16 aporous sensilla trichodea (St), two coeloconic sensilla (Co), one straight multiporous peg (Mp1), and one curvy multiporous peg (Mp2). According to their function, these sensilla can be categorized into three categories: mechanoreceptors, that is, Bb, Ca, Jo, and St; thermo/hygroreceptors, that is, Co only; and chemoreceptors, that is, Mp1 and Mp2. The dendrites that innervate the Mp1, Mp2, and Co sensilla combine to form a large nerve tract (NT1) in the antennal lumen. Because NT1 extends through and out of the antenna, the somata of these neurons are present in the lymph cavity of the insect's head. The dendrites that innervate the mechanoreceptors form another nerve tract (NT2). The somata of these neurons are located inside the scape and pedicel. J. Morphol. 277:1631–1647, 2016. © 2016 Wiley Periodicals, Inc.     

Anatomy of the antennal dorsal organ in female of Neodryinus typhlocybae (Hymenoptera: Dryinidae): A peculiar sensory structure possibly involved in perception of host vibration

Neodryinus typhlocybae (Hymenoptera: Dryinidae) is a natural enemy of the planthopper Metcalfa pruinosa, which was introduced from North America into Europe and has become established in various regions as a pest species. Vibrational signals play a crucial role in the communication of M. pruinosa, which appears to be exploited by N. typhlocybae. Scanning and transmission electron microscopy have shown that the antennae of N. typhlocybae females have peculiar and complex sensory structures: deep longitudinal grooves that house long sensilla trichodea, termed here “Antennal Dorsal Organs.” Such structures were not present on male antennae. These sensilla extend for the length of the grooves, without contact with the groove cuticle. Their hair shaft is empty and aporous, and inserted into a specialized socket, underneath which there is a cuticular ampulla‐like chamber. Each sensillum is associated with two sensory neurons: one terminates at the proximal end of the dendritic sheath; the other continues into the sensillum sinus and is enclosed in the dendritic sheath. This second sensory neuron then enters the ampulla‐like chamber through the circular opening, and then terminates with a conspicuous tubular body at the shaft base. The possible involvement of this peculiar structure in the context of host recognition mechanism is discussed. J. Morphol. 277:128–137, 2016. © 2015 Wiley Periodicals, Inc.     

叉角厉蝽触角转录组及嗅觉相关基因分析

叉角厉蝽Eocanthecona furcellata是一种在生物防治方面有重要作用和潜力的捕食性天敌昆虫,触角是昆虫进行信息交换的重要器官,而嗅觉相关基因则是调控天敌昆虫捕食行为的重要分子基础。为获得叉角厉蝽触角转录组数据库,挖掘叉角厉蝽嗅觉相关基因,本研究利用Illumina高通量测序平台对叉角厉蝽雌雄成虫与5龄若虫触角进行转录组测序。成功构建了叉角厉蝽触角转录组,获得了67 843条unigenes,N50长度为2 300 bp。与七大公共数据库比对注释到27 686条unigenes,其中NR数据库注释最多(33.33%),且与茶翅蝽Halyomorpha halys相似度最高(64.20%)。14 258条注释到GO数据库中,分为生物过程、细胞组分和分子功能3个大类42个亚类;KEGG代谢途径分析表明,7 703条形成282条代谢通路,其中被注释在信号传导通路中的unigenes最多(11.50%)。进一步基因注释分析,鉴定得到134个候选嗅觉相关基因,32个化学感应蛋白基因(Chemosensory protein genes,CSP),10个气味结合蛋白基因(Odorant binding protein genes,OBP),21个气味受体基因(Gustatory receptor genes,GR),48个嗅觉受体基因(Olfactory receptor genes,OR),17个离子型受体基因(Ionotropic receptor genes,IR),6个感觉神经元膜蛋白基因(Sensory neuron membrane protein genes,SNMP)。通过比较叉角厉蝽5龄若虫、雌雄成虫触角转录组,共筛选出7 324个差异表达基因,分析发现5龄若虫与成虫间的差异表达基因较多,雌雄成虫之间差异表达基因较少;利用FPKM值对OBP与CSP基因进行表达量分析发现,大部分OBP与CSP的表达量在雌雄间差异不大,而若虫与成虫相比基因表达量差异较大,除少部分基因在5龄若虫中高表达外,其余大部分基因均在雌雄成虫间高表达。本研究获得了叉角厉蝽触角转录组数据,并鉴定出候选嗅觉相关基因,结果为进一步研究叉角厉蝽的嗅觉感受机制及昆虫化学生态奠定分子基础。     

昆虫触角叶的结构

触角叶是昆虫脑内初级嗅觉中心,通过触角神经与触角联系。触角叶主要由嗅觉受体神经元、局域中间神经元、投射神经元和远心神经元构成。这些神经元的形态多样,其形态变化与其功能和昆虫嗅觉行为相关。这些神经元在触角叶内交织形成神经纤维网,在突触联系紧密的地方形成纤维球,纤维球通常排列在触角叶外周。通常,昆虫触角叶内纤维球的数量、大小和位置相对固定,并且几乎每个小球都可以被识别和命名。不同种类、性别和品级的昆虫中,纤维球的数量、大小和排列方式各不相同。触角叶结构神经元组成和纤维球的多样性,与各种昆虫嗅觉行为的特异性相对应。     

中国榕小蜂触角感受器形态特征及进化适应性分析

【目的】榕树与传粉榕小蜂体系是协同进化、专性传粉的经典系统,每种榕树上一般还生活有种类丰富、数目众多的非传粉榕小蜂。在选择压力下,榕小蜂为在榕果内生存产生了明显的适应性形态。触角感受器是昆虫通讯系统的单元,其形态是反映生态和进化适应性的最佳特征之一。本文旨在对中国部分传粉和非传粉榕小蜂的触角感受器的形态多样性和进化适应性进行系统研究。【方法】对来源于海南和云南15种榕树上24种榕小蜂54个型的触角感受器形态进行了扫描电镜观察,基于现有的分子系统发育树,对传粉榕小蜂触角感受器的形态特征进行了性状演化分析,并对榕小蜂的形态特征进行了进化适应性分析。【结果】榕小蜂触角感受器普遍存在雌雄二型现象。雌蜂触角感受器种类有毛状、锥状、板状、刺状、钟形、腔锥状和栓锥状等,数目丰富,并且进果产卵的传粉雌蜂和果外产卵的非传粉雌蜂之间、进果产卵的传粉雌蜂和进果产卵的非传粉雌蜂之间在形态上存在差异。传粉雄蜂和不具有雄性多型现象的非传粉雄蜂触角感受器极为退化,具有雄性多型的非传粉雄蜂触角感受器形态在种内不具有显著差异。性状演化分析表明进化路径相当复杂,可能存在多次独立进化过程。触角感受器的形态类型与其进化适应性相关。【结论】榕小蜂触角感受器类型多样,形态变化丰富,并为适应榕果内的生存而产生了进化适应性特点。雌蜂和雄蜂在榕果内受到了完全不同的选择压力,行使不同的生态功能,从而产生了不同的适应性形态。不同的适应性形态可能与雌蜂不同的产卵行为、雄蜂不同的交配策略具有一定联系。该文是首次对中国榕小蜂触角感受器形态进行系统研究的报道,有助于更好地理解榕小蜂的形态特征、进化路线、行为策略和生态关系。     

The sox gene Dichaete is expressed in local interneurons and functions in development of the Drosophila adult olfactory circuit

In insects, the primary sites of integration for olfactory sensory input are the glomeruli in the antennal lobes. Here, axons of olfactory receptor neurons synapse with dendrites of the projection neurons that relay olfactory input to higher brain centers, such as the mushroom bodies and lateral horn. Interactions between olfactory receptor neurons and projection neurons are modulated by excitatory and inhibitory input from a group of local interneurons. While significant insight has been gleaned into the differentiation of olfactory receptor and projection neurons, much less is known about the development and function of the local interneurons. We have found that Dichaete, a conserved Sox HMG box gene, is strongly expressed in a cluster of LAAL cells located adjacent to each antennal lobe in the adult brain. Within these clusters, Dichaete protein expression is detected in both cholinergic and GABAergic local interneurons. In contrast, Dichaete expression is not detected in mature or developing projection neurons, or developing olfactory receptor neurons. Analysis of novel viable Dichaete mutant alleles revealed misrouting of specific projection neuron dendrites and axons, and alterations in glomeruli organization. These results suggest noncell autonomous functions of Dichaete in projection neuron differentiation as well as a potential role for Dichaete‐expressing local interneurons in development of the adult olfactory circuitry. © 2012 Wiley Periodicals, Inc. Develop Neurobiol, 2013     

雄性棉铃虫感受性信息素的分子和神经机制研究进展

棉铃虫Helicoverpa armigera主要借助于性信息素通讯完成雌雄识别,实现交配和种群繁衍。关于棉铃虫感受性信息素机制的研究一直是我国化学生态学领域的热点和重心,研究结果有助于开发和改进棉铃虫防治的性引诱剂。本文将对棉铃虫雄虫感受雌虫释放的性信息素的机制进行综述,以期为深入研究棉铃虫及其他相关昆虫的性信息素感受的分子和神经机理提供参考。棉铃虫雌虫性信息素腺体合成和释放多种长链、饱和或非饱和的脂肪醛和醇等化合物,其中Z11-16:Ald为主要性信息素成分,Z9-16∶Ald和Z9-14∶Ald为次要性信息素成分,不同组分按一定比例混合可明显增强对雄性棉铃虫的引诱效果,而化合物Z11-16∶OH和高剂量的Z9-14∶Ald对性信息素引诱活性具有明显的抑制效果。相应地,雄性棉铃虫触角上A, B和C 3种类型的毛形感器能够感受这些信息化合物。A类型毛形感器内表达受体OR13感受Z11-16∶Ald,B类型毛形感器内表达OR14b感受Z9-14∶Ald,C类型毛形感器内表达OR6和OR16感受Z9-16∶Ald, Z9-14∶Ald, Z11-16:Ac和Z11-16∶OH。受体的表达位置和功能与不同类型毛形感器的电生理反应特性相一致。钙离子成像证明在棉铃虫触角叶内的3个扩大型神经纤维球接受这些气味信息,其中神经纤维球云状体接受Z11-16∶Ald,背中间后侧纤维球接受Z9-16∶Ald,背中间前侧纤维球接受Z9-14∶Ald, Z11-16∶Ac和Z11-16∶OH。这些研究成果在感器、受体和脑中枢水平上揭示了棉铃虫感受性信息素的机制,在这些研究基础上,我们认为需要深入开展以下方面的研究：(1)进一步鉴定相关性信息素受体的功能和定位;(2)深入研究脑内嗅觉高级中枢对性信息素信息的处理和整合神经机制;(3)明确棉铃虫性信息素感受受到寄主植物、光周期、温度、湿度等环境因素的影响及机制。     

六斑月瓢虫触角及感觉器扫描电镜观察

[目的] 明确六斑月瓢虫雌雄成虫触角感觉器种类、分布及形态特征。[方法] 利用扫描电子显微镜对六斑月瓢虫雌、雄成虫触角形态及触角感受器超微结构进行观察。[结果] 六斑月瓢虫成虫触角由柄节、梗节和鞭节组成,柄节长度与宽度显著大于梗节长度与宽度;鞭节分为9个亚节,末端3节横向膨大呈锤状。雌雄成虫触角上共有8种感觉器:刺形感觉器(SC)、毛形感觉器(ST)、锥形感觉器(SB)、腔形感觉器(CaS)、钟形感觉器(CS)、哑铃形感觉器(DS)、香肠形感觉器(SS)及B?hm氏鬃毛感觉器(BB)。以毛形感觉器和刺形感觉器分布最广,遍布触角;B?hm氏鬃毛仅存在于触角柄节与梗节;触角鞭节第9亚节顶端密布7种触角感觉器。六斑月瓢虫雌雄成虫触角长度、触角感觉器类型及分布无显著差异。[结论] 六斑月瓢虫成虫触角上共有8种感觉器,其触角可能具有感知机械刺激、识别化学信息素及感受温湿度变化的作用。本研究为进一步了解六斑月瓢虫触角与其行为间的关系提供基础资料。