合哑蝉成虫消化道形态、组织结构及超微结构（英文）

【目的】本研究通过合哑蝉Karenia caelatata成虫消化道的形态学、组织学和超微结构研究,进一步了解蝉科(Cicadidae)代表种类的消化道形态和功能分化。【方法】利用光学显微镜和透射电子显微镜技术,对合哑蝉雄成虫消化道的整体形态以及食道、滤室(中肠前端及后端、马氏管基部、后肠基部)、滤室外中肠(锥形体、中肠环)、后肠(回肠、直肠)的一般形态和超微结构进行了详细观察,同时对滤室的组织结构进行了研究。【结果】结果表明,合哑蝉消化道由食道、滤室、滤室外中肠及后肠组成。食道狭长,被有上表皮和内表皮。中肠前端、中肠后端、马氏管基部以及后肠基部被一肌肉鞘包围形成滤室构造。组成中肠前端和后端的细胞基膜高度内褶,顶端的微绒毛发达。中肠后端分布许多线粒体和高电子密度的分泌颗粒。滤室外的中肠包括膨大的锥形体、中肠环。其中,锥形体由两种细胞组成;中肠环分为前、中、后3个不同的区段。前中肠细胞包含大量的分泌颗粒、线粒体、粗面内质网和溶酶体;中中肠细胞含有分泌颗粒;后中肠细胞包括许多低电子密度的分泌颗粒和滑面内质网。类铁蛋白颗粒零星分布于中肠环的前、中区段。组成锥形体和中肠环前端的细胞顶端微绒毛被丝状物质覆盖。后肠被有一层表皮。食道、中肠环中段、直肠细胞中含有微生物。【结论】本研究获得的合哑蝉消化道形态、组织结构和超微结构方面的信息为其功能分化研究提供了重要信息。同时,相关微生物的发现为进一步探讨共生菌与蝉总科昆虫的协同进化提供了信息。

Morphology,histology andultrastructure of the alimentary canal of the adult mute cicada,Karenia caelatata(Hemiptera: Cicadidae) (In English)

【Aim】In order to better understand the morphology and function of alimentarycanal of insects in Cicadidae, the alimentary canal of the mute cicada, Karenia caelatata,was investigated at the morphological, histological and ultrastructural levels. 【Methods】The gross morphology of alimentary canal, ultrastructure of associated organs includingoesophagus, filter chamber (including anterior and posterior extremities of the midgut,internal proximal extremity of the ileum, and internal proximal extremities of theMalpighian tubules), conical segment, a midgut loop, and hindgut (ileum and rectum), andhistology of filter chamber of male adult of K. caelatata were observed using light andtransmission electron microscopy. 【Results】 The results showed that the alimentary canalof K. caelatata consists of the oesophagus, filter chamber, external midgut section andhindgut. The elongated oesophagus is lined with a cuticle containing an epicuticle and anendocuticle. The filter chamber is enveloped by a thin filter chamber sheath, whichcontains the anterior and posterior extremities of the midgut, internal proximal extremityof the ileum and internal proximal extremities of the Malpighian tubules. Cells of theanterior and posterior extremities of the midgut possess well-developed basal infoldingsand densely-packed apical microvilli. Numerous mitochondria and electron-dense secretorygranules were observed in the posterior extremity of the midgut. The external midgutsection contains a conical segment and a midgut loop. The conical segment is dilated, andconsists of two types of cells: the first is featured by the well-developed basalinfoldings, and the second lacks basal infoldings. The midgut loop is divided into threedistinct regions, i.e., the anterior segment containing numerous secretory granules,mitochondria, rough endoplasmic reticulum and lysosomes in the cytoplasm, the mid-segmentcontaining secretory granules in the cytoplasm, and the posterior segment with cellspossessing numerous electron-lucent secretory granules and smooth endoplasmic reticulum.Ferritin-like granules scatter in the cells of the anterior segment and mid-segment ofthe midgut loop. Filamentous materials coat the microvilli of the cells of the conical andanterior segments of the midgut loop. The hindgut is lined by a layer of cuticle.Microorganisms reside in the oesophagus, mid-segment of the midgut loop and rectum cells.【Conclusion】 Findings of the morphological, histological and ultrastructuralcharacteristics of the gut alimentary canal of K. caelatata in this study improve ourunderstanding of the functional differentiation of alimentary canal in this species. Thediscovery of microorganisms in the alimentary canal is formative to future study ofcoevolution between the Cicadoidea and related bacteria.