蟋蟀脑的解剖结构与生理机能

蟋蟀脑由前脑、中脑和后脑三部分组成。前脑由1对蕈形体、中央复合体和视叶构成;每个蕈形体由2个冠、柄及与柄相连的α叶和β叶组成,是信息联络整合部位;中央复合体由中央体和脑桥组成,主要参与感觉信息的加工过程;视叶由神经节层、外髓和内髓组成,是视觉系统的中心。中脑由主要组成成分为嗅觉纤维球的嗅叶组成,是嗅觉系统的中心。后脑向后与食道下神经节相连。     

昆虫嗅觉系统结构与功能研究进展

昆虫的脑由前脑、中脑和后脑组成,其中前脑含有高级感觉中枢,如蘑菇体和中央复合体,控制昆虫的学习、记忆和运动等高级神经活动;中脑包含触角叶,是嗅觉神经中心;而后脑则通常不发达,主要包括内分泌神经元和控制进食与消化的运动神经元。不同于其他物种,昆虫由于其特殊的生活习性,听觉和视觉系统相对退化,主要依赖嗅觉来捕食、交流和求偶,因此嗅觉系统尤其发达。本文综述了目前对昆虫的脑部主要神经结构和功能(中央复合体、蕈形体和触角叶结构)以及昆虫脑部结构遗传变异(性别异构,不同发育时期、不同昆虫以及昆虫与其他动物的脑部结构差异)的研究进展,并总结了目前昆虫脑对信号的加工处理和识别机制的研究结果。     

茶尺蠖幼虫脑的解剖结构

【目的】明确茶尺蠖Ectropis obliqua Prout 5龄幼虫脑解剖结构,并分析和构建幼虫脑以及脑内部各神经髓结构的三维结构模型。【方法】采用免疫组织化学方法,利用突触蛋白抗体,染色标记脑内神经突触,定位突触联系密集分布的区域,获得脑内部神经髓的结构。利用激光共聚焦显微镜获取脑扫描图像,然后利用三维图像分析软件AMIRA进行图像分析,构建脑的三维结构模型,并计算脑以及脑内各神经髓结构的体积。【结果】突触蛋白抗体染色显示,茶尺蠖5龄幼虫脑内具有很多神经突触联系密集分布的区域,这些不同区域即为脑的不同神经髓结构。茶尺蠖幼虫脑主要包括前脑、中脑和后脑3个组成部分。其中前脑最大,包括成对的视叶、蕈形体、前脑桥和侧副叶以及不成对的中央体。视叶位于前脑的两侧后端。蕈形体位于脑半球正中间位置。侧副叶在中央体的下前方两侧。中央体在脑的正中心。前脑桥在中央体的上方后侧。除这些形态结构明显的神经髓区域外,前脑还包括大量内部边界不明显的神经髓区域,位于前脑左右两侧以及背侧和腹侧,这些区域被总称为中间脑,占整个脑神经髓的66%。触角叶为中脑的主要组成部分,在脑的下部最前端,为一对球状结构。后脑在脑的腹侧和触角叶下方,即围咽神经索进入脑的入口处。【结论】构建了茶尺蠖5龄幼虫脑以及各神经髓结构三维模型,分析了脑内各个神经髓之间的空间位置关系,明确了各神经髓的体积。茶尺蠖幼虫脑体积小而且结构简单的特征与其幼期视觉、嗅觉等感觉器官不发达、活动能力弱、行为简单的生物学习性相对应。     

中华蜜蜂蕈形体的发育

中华蜜蜂(Apis cerana cerana)的脑由前脑、中脑和后脑三部分构成,蕈形体位于前脑的背侧,是其重要的学习及其他复杂行为的整合中心。通过对中华蜜蜂工蜂的幼虫、蛹及成虫的蕈形体形态发育的观察研究,发现中华蜜蜂的蕈形体包含约1000个成神经细胞,它们最终形成了蕈形体的所有Kenyon细胞。这些成神经细胞来自于在新孵化的幼虫脑中已存在的四丛成神经细胞,每一丛细胞的数量不多于45个。蕈形体柄区的出现约在3龄幼虫,而α叶和β叶在5龄幼虫已可明显辨认。冠区出现较晚,大约在蛹期的第二天以后。由于社会性昆虫复杂的学习、记忆和认知需求,其蕈形体的体积和复杂程度都优于其他昆虫。     

棉铃虫幼虫脑和咽下神经节的三维结构构建

【目的】解剖棉铃虫Helicoverpa armigera (Hübner) 5龄幼虫脑和咽下神经节及其内部神经髓形态结构,并分析和构建幼虫脑和咽下神经节以及各神经髓的三维结构模型。【方法】采用免疫组织化学方法解剖脑和咽下神经节的内部神经髓结构,利用激光共聚焦显微镜获取脑和咽下神经节扫描图像,然后利用AMIRA 三维图像分析软件进行图像分析,从而构建脑和咽下神经节的三维结构模型,并测量脑和咽下神经节以及内部各神经髓的体积,并分析了相对比例。【结果】 棉铃虫5龄幼虫脑和咽下神经节由围咽神经索连接在一起。脑主要由前脑、中脑和后脑3部分组成。前脑内包括视叶、蕈形体和中央体等形态结构较明显的神经髓。此外,前脑还包括其他位于脑的左右两侧以及背侧和腹侧大量神经髓区域,约占脑总神经髓的59.65%。这些神经髓区域边界不明显。中脑主要包括1对触角叶;后脑位于脑的腹侧和触角叶的下方,体积较小。咽下神经节由3个神经节融合构成,从前到后分别为上颚神经节、下颚神经节和下唇神经节,由于融合的紧密程度高,3个神经节间的边界不明显。【结论】阐明了棉铃虫5龄幼虫脑和咽下神经节的神经髓形态结构,构建了脑和咽下神经节以及内部神经髓的三维结构模型。三维模型可以任意旋转,能从任何角度观察脑、咽下神经节和内部不同神经髓的结构及其它们之间的空间关系。本研究结果对研究棉铃虫脑和咽下神经节信息接收、处理及调控行为的机制奠定了解剖学基础。     

光肩星天牛种群间及其近缘种遗传关系的RAPD研究

利用RAPD技术对采自中国和美国的星天牛属Anoplophora 5个种及8个光肩星天牛Anoplophora glabripennis (Motschulsky)地理种群共13个样品进行了遗传相似性分析。选用了Operon公司生产的引物H系列20个,L系列20个,Q系列11个共51个引物,最后从40个引物中筛选出26个具有多态性的引物作为第一组用于星天牛属种间和光肩星天牛种群间分析,从31个引物中筛选出19个具有多态性的引物作为第二组单独用于光肩星天牛种群分析。根据第一组引物实验获得的RAPD聚类图及遗传距离表明,各个地理种群的光肩星天牛和黄斑星天牛A. nobilis都聚在一起,形成一个大的分枝,而四川星天牛A. freyi、楝星天牛A. horsfieldi和星天牛A. chinensis均在此分枝之外。来自美国纽约和芝加哥的光肩星天牛种群聚于中国光肩星天牛种群之外的另一个独立的分枝上。分布在我国宁夏、内蒙古和河北的光肩星天牛以及宁夏黄斑星天牛和山东、陕西的光肩星天牛分别聚在一起,而甘肃的光肩星天牛与甘肃的黄斑星天牛则聚于另一枝,且它们之间的遗传距离很近,仅为0.1324,说明这两者之间有着极其相近的亲缘关系,由此推断光肩星天牛和黄斑星天牛的差异很小,遗传关系难以区分,进一步证实了它们很可能是同一个种下的两个不同的型。第二组引物实验得到了相似的结果,来自中国的6个光肩星天牛种群全部聚于同一枝中并分成两小枝： 分布于我国宁夏、河北、山东、甘肃的光肩星天牛聚在一起,内蒙古和陕西的光肩星天牛则成另一枝,而分布于美国纽约和芝加哥的光肩星天牛仍聚于中国光肩星天牛种群之外的一个单独的分枝上。但是美国光肩星天牛与中国光肩星天牛之间的遗传距离最近的为0.4578, 最远的为0.5960。由此认为,本研究中采自美国的两个光肩星天牛种群的样本和采自中国的光肩星天牛种群的样本之间存在显著差异,遗传关系较远。有必要从中国和世界其他天牛分布地采集更多样本做进一步DNA 分析。     

中华蜜蜂雄蜂脑部组织结构观察

通过组织化学方法,对中华蜜蜂Apis cerana cerana Fabricius雄蜂的脑部的形态结构进行观察。结果表明,雄蜂的脑由前脑、中脑和后脑三部分构成,前脑视叶两侧具有大而显著的复眼,而其他结构相对较小。蕈形体在脑中所占的比例小于工蜂和蜂王;中心体的比例小于工蜂,与蜂王接近;中脑的嗅叶相对较为发达,这使它们在同蜂王的交配过程中,能够更灵敏地接收来自于蜂王性外激素的刺激。中华蜜蜂雄蜂的嗅叶具有性二态现象,但是与意大利蜜蜂Apis mellifera L.雄蜂发达的巨大纤维球复合体相比,中华蜜蜂并不明显;除此之外,它们在脑部结构上没有显著差异。     

光肩星天牛气味结合蛋白AglaOBP12的基因克隆、表达及配体结合特征

【目的】克隆和鉴定光肩星天牛Anoplophora glabripennis气味结合蛋白(odorant binding proteins,OBPs)基因,明确其表达特点及与寄主植物挥发物的结合特性,有助于阐明光肩星天牛嗅觉识别的分子机制。【方法】根据光肩星天牛雌成虫触角转录组数据,利用RT-PCR克隆OBP12基因,并进行生物信息学分析。通过实时定量PCR(qRT-PCR)测定OBP12在光肩星天牛成虫触角、头(移除触角)、胸、腹、足、翅中的转录水平。利用原核表达系统和Ni离子亲和层析技术表达和纯化OBP12重组蛋白,荧光竞争结合实验测定重组蛋白与39种气味配体的结合能力。【结果】获得光肩星天牛气味结合蛋白基因AglaOBP12(GenBank登录号:KX890109)的完整编码序列,其开放阅读框长414 bp,编码137个氨基酸,N末端具有18个氨基酸组成的信号肽序列,蛋白序列具有6个保守的半胱氨酸残基,Agla OPB12属于Classical OBPs亚家族基因。qRT-PCR测定结果表明,AglaOBP12主要在成虫触角中表达,在其他组织微量表达。在待测的39种寄主植物挥发物中,重组蛋白AglaOBP12仅与19种化合物具有结合活性,表明AglaOBP12对寄主植物挥发物具有明显的选择结合特性。重组蛋白AglaOBP12与十二烷醇、十四烷醇、法尼醇、十二醛、乙酸-顺-3-己烯酯和β-石竹烯的结合能力较强,结合常数分别为1.96,0.96,1.03,0.82,0.77和0.74μmol/L。【结论】明确了AglaOBP12的核苷酸和氨基酸序列组成,重组AglaOBP12蛋白与主链有12个碳原子的醇类、醛类和萜烯类挥发物有特异性的结合活性。根据AglaOBP12基因的表达特点和重组蛋白的结合特性,推测AglaOBP12在光肩星天牛成虫定位补充营养寄主植物中发挥重要作用。     

中国的光肩星天牛类群

该文讨论我国光肩星天牛Anoplophoraglabrlpennis(Motschulsky)类群的外部形态和外生殖器的主要鉴别特征,寄主、地理分布、起源及其演化。光肩星天牛主要分布在山西吕梁山、太行山以东的广大平原地区,寄主广泛,主要有榆、复叶槭、杨、柳、五角枫等。黄斑星天牛主要分布在秦岭以北,山西吕粱山太行山以西的陕甘宁地区,向东已扩展到河南、河北;主要为害杨树,也为害柳、榆。四川星天牛主要分布于秦岭以南的西部地区,北限在陕西太白山到甘肃天水一带;主要为害柳。在秦岭以北到天水之间是黄斑星天牛和四川星天牛的重叠分布区,山西太行山两侧南北走向的狭长地带是光肩星天牛和黄肩星天牛重叠分布区,两个狭长地带交会处,大约在秦岭以北的陕西和(或)山西境内有三个种的重叠分布区域.在云、贵、川地区广泛分布着四川星天牛,至今还没有发现光肩星天牛、黄斑星天牛和蓝角星天牛,后者应该是一个值得怀疑的种。     

锈色粒肩天牛触角感器的扫描电镜观察

利用扫描电镜对锈色粒肩天牛Apriona swainsoni雌、雄成虫触角上的感器结构、分布及数量进行观察和研究。结果表明:锈色粒肩天牛成虫触角鞭节状,由柄节,梗节和9节鞭节组成。在雌、雄成虫触角上分布着4类8种感器,分别是2种毛形感器,2种刺形感器,3种锥形感器和1种芽形感器。而发锥形感器和短刺形感器只分布于雄虫的触角上,不同类型感器在雌、雄个体上的长度及分布数量不同。     

烟青虫成虫脑结构解剖和三维模型构建

【目的】解剖分析烟青虫 Helicoverpa assulta 成虫脑的结构,并构建脑三维结构数字化模型。【方法】利用神经突触蛋白抗体,对烟青虫成虫脑进行免疫组织化学染色标记,利用共聚焦激光扫描显微镜获得脑扫描数码图像,并结合三维图像分析软件对烟青虫脑结构进行识别分析,构建三维模型。【结果】突触蛋白抗体免疫染色将烟青虫脑和颚神经节的神经髓区域清晰标记出来。烟青虫成虫脑与颚神经节愈合而成为一体,中间具有一个孔洞,为食道穿过的通道。脑主要包括前脑、中脑和后脑3部分。依据染色标记结果识别和构建了至少16个脑神经髓结构。这些神经髓包括边界清晰的视叶、前视结节、蕈形体、中央复合体和触角叶及其亚结构。除此之外,还包括围绕这些神经髓的其他前脑神经髓区域,但这部分前脑神经髓内部边界模糊,不容易细分,而将其与颚神经节区域作为一个整体标记为中间脑,占脑总神经髓的55.05%。【结论】识别出烟青虫脑的主要功能结构区域,并成功构建了三维模型。该研究结果为进一步研究烟青虫脑接收、处理和整合感觉信息及调控行为的机制奠定了解剖学基础,并为研究烟青虫或其他昆虫脑结构发育、变异和重塑提供结构形态和体积大小依据。     

Physiology and morphology of olfactory neurons associating with the protocerebral lobe of the honeybee brain

Physiology and morphology of olfactory neurons associated with the protocerebral lobe around the alpha-lobe of the mushroom body were studied in the brain of the honeybee Apis mellifera using intracellular recording and staining techniques. The responses of neurons to behaviorally relevant odorants (a blend, and components of the Nasonov pheromone, and some other non-pheromonal odors) were recorded. Different response patterns were observed within different neurons, and often within the same neuron, in response to different stimuli. All the neurons stained had innervations in the protocerebral lobe. The cell profiles varied from cells connecting the antennal lobe with both the protocerebral and lateral protocerebral lobes (projection neurons), cells linking the pedunculus of the mushroom body with both the protocerebral and lateral protocerebral lobes (PE1 neurons), cells linking the alpha-lobe and protocerebral lobe with the calyces of the mushroom body (feedback neurons), and cells linking the alpha-lobe and protocerebral lobe with the antennal lobe (recurrent neurons), to cells connecting the protocerebral lobe with the contralateral protocerebrum (bilateral neurons). These findings suggest that the protocerebral lobe acts as an olfactory center associating with other centers, and provides multi-layered recurrent networks within the protocerebrum and between the deutocerebrum and the protocerebrum in honeybee olfactory pathways.     

Multimodal interneurons in the cricket brain: properties of identified extrinsic mushroom body cells

Summary 322 neurons were recorded intracellularly within the central part of the insect brain and 150 of them were stained with Lucifer Yellow or cobaltous sulphide. Responses to mechanical, olfactory, visual and acoustical stimulation were determined and compared between morphologically different cell types in different regions of the central brain. Almost all neurons responded to multimodal stimulation and showed complex responses. It was not possible to divide the cells into different groups using physiological criteria alone.Extrinsic neurons with projections to the calyces connect the mushroom bodies with the deutocerebrum and also with parts of the diffuse protocerebrum. These cells probably give input to the mushroom body system. The majority are multimodal and they often show olfactory responses. Among those cells that extend from the antennal neuropil are neurons that respond to non-antennal stimulation (Figs. 1, 2).Extrinsic neurons with projections in the lobes of the mushroom bodies often project to the lateral protocerebrum. Anatomical and physiological evidence suggest that they form an output system of the mushroom bodies. They are also multimodal and often exhibit long lasting after discharges and changes in sensitivity and activity level, which can be related to specific stimuli or stimulus combinations (Figs. 3, 4).Extrinsic neurons, especially those projecting to the region where both lobes bifurcate, exhibit stronger responses to multimodal stimuli than other local brain neurons. Intensity coding for antennal stimulation is not different from other areas of the central protocerebrum, but the signal-tonoise ratio is increased (Fig. 5).Abbreviation AGT antenno-glomerular tract     

The developmental expression of serotonin-immunoreactivity in the brain of the pupal honeybee

The biogenic amine serotonin is a neurotransmitter and modulator in both vertebrates and invertebrates. In the CNS of insects, serotonin is expressed by identifiable subsets of neurons. In this paper, we characterize the onset of expression in the brain and suboesophageal ganglion of the honeybee during pupal development. Several identified serotonin-immunoreactive neurons are present in the three neuromeres of the suboesophageal ganglion the dorsal protocerebrum, and the deutocerebrum at pupal ecdysis. Further immunoreactive neurons are incorporated into the developing pupal brain in two characteristic developmental phases. During the first phase, 5 days after pupal ecdysis, serotonin immunoreactivity is formed in the protocerebral central body, the lamina and lobula, and the deutocerebral antennal lobe. During the second phase, 2 days later, immunoreactivity appears in neurons of the protocerebral noduli of the central complex, the medulla, and the pedunculi and lobes of the mushroom bodies. Three novel serotonin-immunoreactive neurons that innervate the central complex and the mushroom bodies can be individually identified.     

Building the antennal lobe: engrailed expression reveals a contribution from protocerebral neuroblasts in the grasshopper Schistocerca gregaria

The expression pattern of the engrailed protein was studied in neuroblasts which delaminate at the border of the protocerebrum and antennal lobe of the deutocerebrum in the early embryonic brain of the grasshopper. The antennal lobe is a complex structure comprising both glomerular and non-glomerular components, a cellular organization which distinguishes it from the striate-like neuropil comprising the remainder of the deutocerebrum. Early in embryogenesis engrailed expression in the protocerebrum is restricted to a compact block of neuroblasts located at its interface with the antennal lobe. Subsequently engrailed expression in these cells disappears in a stepwise manner from anterior to posterior so that by 37% of embryogenesis only a single row of three engrailed positive neuroblasts and their progeny remains. Contemporaneously engrailed expression reappears in a group of more anterior progeny deriving from neuroblasts which are no longer immunoreactive. The three remaining engrailed positive neuroblasts then become separated from their non-immunoreactive neighbours by an invagination of the perineurium called the lateral cleft and come to lie completely within the developing antennal lobe. These cells then direct columns of immunoreactive progeny centrifugally towards the centre of the lobe. Such a protocerebral contribution to the antennal lobe suggests that the evolution and ontogeny of this brain region need to be reconsidered.     

Morphology of descending statocyst interneurons in the crayfish Procambarus clarkii Girard

Summary The morphological features of descending interneurons that responded to the artificial bending of statolith hairs were assessed with intracellular recording and staining techniques. Seven statocyst interneurons were identified on the basis of their structure and response characteristics and designated as interneurons S1 to S7. All seven identified interneurons project to the optic lobe, where the optic nerve also projects, and to the dorsal part of the tritocerebrum, where the eyestalk motoneurons originate. All except interneuron S6 also extend their major branches to other neuropilar regions. S2 projects to the dorsal part of the deutocerebrum, where the statocyst nerve terminates, and S3 to the dorsal part of deutocerebrum and the antennal lobe. Four other interneurons (S1, S4, S5, S7) also extend their branches to the parolfactory lobe to which the statocyst nerve projects as well as to the deutocerebrum and antennal lobe. The extensive dendritic projections of S1–S7 suggest that they are complex multimodal interneurons rather than simple relay interneurons, receiving at least visual and statocyst sensory information. The function of the antennal lobe branches, however, has yet to be determined since the functional role of antennal input in equilibrium control is unknown.