人工养殖稀有鮈鲫消化道组织学观察

采用活体解剖和显微技术对人工养殖的稀有鮈鲫消化道组织结构进行了详细观察,并描述了其形态结构。结果表明:稀有鮈鲫为杂食性无胃鱼,肠道系数0.64±0.06。消化道包括口咽腔、食道、肠和肛门。口咽腔和食道粘膜层为复层扁平上皮,内含较多杯状细胞、粘液细胞和少量味蕾;食道粗短,肌肉层发达。肠由前肠、中肠和后肠三部分组成。肠道由前到后,粘液细胞数量逐渐增多,粘膜皱褶数量逐渐减少,粘膜皱褶高度逐渐降低。     

光唇鱼消化道的形态结构特征

采用解剖及石蜡切片显微技术,观察研究了光唇鱼消化道的形态结构特征。消化道由口咽腔、食道、肠构成。口下位、马蹄形,无颌齿,具咽齿,齿式为4/4。舌较小,前端游离,舌粘膜表层为复层鳞状上皮,有较多的杯状细胞和味蕾。食道及肠均由粘膜层、粘膜下层、肌层及外膜构成。食道内皱襞发达,粘膜层有大量杯状细胞。肠道盘曲,由前、中、后肠组成,肠长/体长为1.84±0.24;前肠管腔较大,中、后肠管腔渐变小;前、中肠皱襞及纹状缘比后肠发达;前肠及后肠杯状细胞较少,中肠杯状细胞较多。光唇鱼消化道的形态结构特征与其食性相适应。     

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。     

日本沼虾消化道形态和组织学特点

应用石蜡切片和扫描电镜技术对日本沼虾消化道进行了研究。结果表明,食道壁向腔内形成四个纵突,食道上皮由单层柱状细胞构成,上皮下的结缔组织中具有放射肌和皮肤腺,环肌层近于连续。食道和胃连结处的管腔背方具食道瓣,胃内具胃磨、滤器和滤沟等结构,胃的组织学结构中除无皮肤腺分布外与食道相似。中肠较长,约占整个消化道的７１７％,具一对中肠前盲囊。中肠上皮细胞大致有两种类型,基膜着色深,环肌层连续,纵肌成束分散排列。后肠为一短管,管腔呈迷路状,其中部为一球形膨大的直肠。后肠的组织学结构与前肠相似。     

美洲黑石斑鱼消化道的形态结构

采用解剖和光镜技术观察了美洲黑石斑鱼消化道的形态及组织学结构。消化道由口咽腔、食道、胃、肠构成。口咽腔较大,具颌齿、腭齿及犁齿;舌由基舌骨突出部分覆盖粘膜构成。食道、胃及肠均由粘膜层、粘膜下层、肌层及外膜构成。食道粘膜层绒毛分柱状上皮区及扁平上皮区,扁平上皮区表面为杯状细胞层;食道粘膜下层中有食道腺。胃呈V形,由贲门部、胃体部及幽门部组成,胃壁粘膜层上皮为单层柱状上皮,胃腺位于贲门部与胃体部的固有层中。肠细长,呈S型,由前、中、后肠构成,粘膜层向肠腔突起形成肠绒毛,粘膜上皮为单层柱状上皮,上皮游离面有微绒毛密集排列而成的纹状缘,上皮中含有杯状细胞,且杯状细胞的数量从前向后呈递减趋势;肠长/体长约为1.6。胃与小肠相接处有3对指状幽门盲囊,幽门盲囊的组织学结构与肠相同。     

黑水虻消化道形态及组织结构的观察

本文比较了不同发育阶段黑水虻Hermetia illucens消化道的形态学差异,掌握了幼虫消化系统的组织学特征。利用体视镜观察黑水虻5龄幼虫、预蛹及成虫的消化道形态,利用光学显微镜和扫描电镜观察幼虫消化道各段（前肠、中肠、后肠）的显微及超微结构。结果表明：黑水虻幼虫及预蛹的消化道均由前肠（食道和前胃）、中肠及后肠组成,从幼虫到成虫,消化道的长度不断缩短。与幼虫和预蛹相比,成虫消化道形态变化明显,前胃消失,出现了嗉囊及胃盲囊,中肠进一步缩短,后肠分化为回肠、结肠和直肠。组织学观察结果显示,幼虫的唾液腺开口于口腔,由膨大的管状腺体和腺管组成。食道由特化为角质刺突的内膜层及发达的肌层组成,其末端延伸至前胃。前胃膨大为球状,包括三层组织结构。根据上皮细胞形态的差异,中肠可分为四个区段。后肠薄,肠腔内褶丰富,肠壁可见数量较多的杆状细菌。马氏管开口于中、后肠交界处,包括4支盲管,管内壁密布微绒毛。黑水虻消化道形态随发育阶段的变化,反映了各阶段摄食及消化生理的差异。幼虫消化道各段具有各自典型的组织学特征,其前、中、后肠可能分别承担了食物接纳与初步消化、消化与吸收以及重吸收功能。本研究结果为进一步了解黑水虻的消化生理特征提供了重要的形态学和组织学依据。     

团头鲂消化道黏膜ACP、ALP、NSE、SDH、ATPase的组织化学定位

目的研究团头鲂消化道各部位酸性磷酸酶(ACP)、碱性磷酸酶(ALP)、非特异性酯酶(NSE)、琥珀酸脱氢酶(SDH)、腺苷三磷酸酶(ATPase)的分布与定位。方法运用冰冻切片、酶的组织化学技术和光密度定量分析。结果 ACP在消化道各段均有分布,后肠酶活性最高,其次为前肠,食道和中肠酶活性最低;ALP在前肠和中肠酶活性最高,后肠酶活性较低,食道中未检测出酶活性;NSE在消化道各段均有分布,前肠酶活性最高,其次为中肠和后肠,食道酶活性最低;SDH在前肠酶活性最高,中肠酶活性较低,食道和后肠未检测出酶活性;ATPase在消化道各段均有分布,中肠酶活性最高,其次为前肠和后肠,食道酶活性最低。结论不同酶在消化道各部位的活力不同,与消化道各部位的生理功能相适应。团头鲂消化道5种酶的分布表明其前肠是脂类的主要消化部位,中肠是营养物质的主要吸收部位,后肠有较强的吸收蛋白质和细胞内消化功能。     

花消化系统形态学及组织学的初步观察

采用活体解剖、测量及HE、AB-PAS染色等方法,对45尾体长范围11.30~28 cm花Hemibarbus maculates Bleeker的消化系统形态学、组织学特征进行了研究。结果表明,花消化系统具有以下特点:(1)消化系统包括消化道和消化腺两部分。消化道包括口咽腔、食道、肠和肛门,消化腺包括肝胰脏和胆囊,无胃。(2)口下位,吻尖而细长,口裂长/吻长雄性显著大于雌性(P0.05);口咽腔黏膜上皮为复层鳞状上皮,内有黏液分泌细胞和味蕾结构。(3)食道粗短,前段有味蕾,肌层发达且内壁有较深的纵向褶皱,黏膜层内有大量的杯状细胞、黏液分泌细胞,还有柱状上皮区域,游离面具有纹状缘。(4)肠呈S型,无肠腺,分为前肠、中肠和后肠,比肠长均值为0.98±1.29;食道粘膜下层及环肌层最厚与肠道各段有极显著差异(P0.01)。前肠、中肠和后肠黏膜皱褶数量、黏膜皱褶高度、黏膜下层厚度、杯状细胞数量显著减少(P0.05),浆膜层厚度却增加,前肠和后肠有显著差异(P0.01)。(5)食道和肠道的黏膜层发现有数量较多的颗粒细胞。(6)肝不分叶,为长条形,胆囊被肝包围;肝与胰脏不分开,胰脏弥散于肝、脾及肠管之间,比肝胰脏重(%)雄性(1.83±0.64)显著大于雌性(1.34±0.50)(P0.05)。(7)体长(L)与消化道长(Y)的关系呈线性相关:Y=1.1692L+1.2688(R2=0.653)。     

生长抑素在齐口裂腹鱼消化道和脑中的定位

采用链霉亲合素一生物素过氧化物酶复合物免疫组化法研究生长抑素（Somatostatin,Som）在齐口裂腹鱼（Schizothorax prenanti）脑和消化道中的定位。在消化道中,口咽腔和食道为阴性反应;肠道有Som强阳性细胞,其中前肠密度最高,后肠最低。这些Som阳性细胞多分布于粘膜上皮,形态多样。肠道巨噬细胞呈Som强阳性反应。Som广泛分布于各脑区的神经元或神经纤维中,呈弱或强阳性反应,其中下丘脑下叶乳头体内Som阳性细胞密度最高,背嗅核、侧嗅核、原始纹体、视前核、内嗅沟旁、缰核下区、前丘脑核、前圆核、下丘脑中叶、下丘脑下叶、中脑室侧次之;小脑分子层和延脑VI、V核较少。端极和脑上腺有阳性神经纤维。这说明Som在肠道中的分布与该鱼食性、消化道结构和功能密切相关;Som在下丘脑中的分布特点为鱼类GH调控提供了形态学证据;Som在脑中广泛分布,提示可能作为一种神经递质或调质,发挥更为广泛的生理功能。     

红螯螯虾胚胎发育的研究:Ⅱ.消化系统的发生

应用组织切片技术 ,研究了红螯螯虾胚胎发育过程中消化系统的发生。红螯螯虾的消化系统由前肠、中肠和后肠 3部分组成 ,前肠和后肠由外胚层形成 ,而中肠源自原肠期由胚胎表面向囊胚内迁移的中内胚层细胞团。前无节幼体期前肠开始发生 ,至后无节幼体期先后形成口道、食道和胃等结构 ;中肠起始于后无节幼体期的次级卵黄锥 ,包括管状中肠和 1对囊状消化腺 -中肠腺 ;后肠端部是前无节幼体期形成的肛道 ,肛道不断向胚胎前端延伸逐渐形成后肠     

Distribution of lysozyme and protease, and amino acid concentration in the guts of a wood-feeding termite, Reticulitermes speratus (Kolbe): possible digestion of symbiont bacteria transferred by trophallaxis

Distribution of lysozyme and protease, and amino acid concentration in the guts of a wood‐feeding termite, Reticulitermes speratus (Kolbe) (Isoptera, Rhinotermitidae) were studied to examine the possibility that termites digest symbiont bacteria transferred by trophallaxis. Total lysozyme activity was found predominantly in the salivary gland and to a minor extent in the digestive tracts. However, specific lysozyme activity was high in the foregut as well as in the salivary gland. The similarity of the lysozyme pH profile of the salivary gland and of the foregut suggested that the foregut lysozyme came from the salivary gland. Major protease activity having the optimum pH of 7.5 was found in the midgut. Total free amino acid amount and concentration in the midgut was higher than elsewhere in the digestive tract. The possibility that lysozyme secreted from the salivary gland into the foregut digests hindgut bacteria transferred by trophallaxis was discussed.     

The digestive tract of Helicoradomenia (Solenogastres, Mollusca), aplacophoran molluscs from the hydrothermal vents of the East Pacific Rise

Abstract. Species of Helicoradomenia are constantly found at hydrothermal vent sites of the eastern and western Pacific Ocean. The digestive tract of 2 species of the genus was investigated with special focus on the ultrastructure and histochemistry of epithelia and glandular organs. The preoral cavity and foregut epithelia are composed of microvillous main cells, secretory cells producing protein-rich substances, and sensory cells with specialized cilia. The foregut bears a pair of glands with 3 types of extremely long-necked glandular cells surrounded by musculature. Each glandular cell opens directly into the radula pocket without a gland duct. The large radula apparatus consists of pairs of denticulated bars resting on a flexible radular membrane without elaboration of a subradular membrane. The midgut has a narrow, mid-dorsal tract of ciliary cells, but most of the epithelium is composed of digestive cells with a highly developed lysosomal system. The hindgut is lined by ciliated cells and free of glands. The foregut and radula seem to be highly efficient in the capture of relatively large, motile prey. Food contents within the midgut lumen and within some of the large secondary lysosomes indicate a triploblastic metazoan prey of non-cnidarian origin. The digestive tract is not adapted to microvory and there is no indication of a symbiosis with chemoautotrophic bacteria.     

Ultrastructure of the digestive system and the fate of midgut during embryonic development in Porcellio scaber (Crustacea: Isopoda)

Microscopic anatomy of the digestive system in embryos and larvae of the terrestrial isopod crustacean Porcellio scaber was investigated by light bright field, fluorescence and electron microscopy. During marsupial ontogenetic development the event-dependent staging was used to discriminate the various embryonic stages. At the late embryo stage the differentiation of the ectodermal part of the gut into the complex filtering foregut and the hindgut with absorptive and transporting functions is accomplished. The gut of the marsupial manca larva is fully developed and similar to that of the adult. In early embryos the endodermal midgut gland primordia are filled with yolk and lipid globules. In late embryos the epithelium of paired midgut gland tubes is composed of two cell types; one of them exhibits orange autofluorescence. The endodermal cells located between the foregut and the midgut glands of late embryos form the prospective midgut. The cells have electron dense cytoplasm, abundant glycogen fields, endoplasmic reticulum, dictyosomes and numerous vesicles. In the adults the endodermal cells of the midgut remain only in the midgut gland ducts which connect the midgut glands and the foregut. Details of the cellular ultrastructure and morphogenesis of the ectodermal and endodermal parts of the digestive system during embryonic development of Porcellio scaber provide data for further phylogenetic and comparative studies in peracaridan crustaceans and other arthropods.     

Dual cellulose-digesting system of the wood-feeding termite,Coptotermes formosanus Shiraki

The distribution of endo-beta-1,4-glucanase (EG) components in the digestive system of the wood-feeding termite, Coptotermes formosanus Shiraki, was investigated by zymogram analysis using polyacrylamide gel electrophoresis, followed by N-terminal protein sequencing. EG components similar to glycoside hydrolase family (GHF) 9 members were restricted to the salivary glands, the foregut, and the midgut, whereas components similar to GHF7 members were confined to the hindgut where numerous cellulolytic flagellates were harbored. RT-PCR experiments revealed that five GHF9 EG mRNAs (1348 bp) homologous to other termite EGs were expressed in the salivary glands and the midgut. The crude extract prepared from the midgut as well as that from the hindgut produced glucose from crystalline cellulose. These data suggest that C. formosanus has two independent cellulose-digesting systems: one in the midgut where cellulose digestion is accomplished by endogenous cellulases and the other in the hindgut which makes use of other cellulases possibly from symbiotic flagellates.     

Morphology of the sweet potato whitefly,Bemisia tabaci (Homoptera,Aleyrodidae) relative to virus transmission

 The stylet bundle of the sweet potato whitefly, Bemesia tabaci, consists of paired mandibles and maxillae. The latter interlock to form the food and salivary canals. Its salivary system consists of paired primary and accessary glands in the thorax. Primary and accessory gland ducts on each side of the nerve cord fuse to form lateral ducts that course anteroventrally to the midline and continue in parallel down the hypopharynx to eventually fuse to form the single afferent duct of the salivary pump. Saliva exiting the pump via the efferent duct enters the salivary canal of the maxillae. Food from the maxillary food canal passes from the antecibarium to the postcibarium or sucking pump and, per os, to the pharynx and esophagus of the foregut. The esophagus extends from the head to the base of the abdomen where it and the anterior midgut intimately mingle with the anterior hindgut to form a filter chamber. The midgut then proceeds dorsocaudally before looping anteroventrally to join the hindgut. The latter gives off two fingerlike Malpighian tubules before entering the filter chamber, whence it proceeds dorsocaudally to the anus within the vasiform orifice. Where possible, the morphology of Bemisia is discussed in relation to plant virus transmission and the morphologies of more thoroughly studied homopteran vectors such as aphids and leafhoppers. Accepted: 9 July 1996     

The functional morphology of the alimentary tract of barnacles (Cirripedia: Thoracica)

The alimentary tract of barnacles is made up of cuticle-lined foregut and hindgut with an intervening U-shaped midgut associated anteriorly with a pair of pancreatic glands and perhaps midgut caeca. Epithelial salivary glands secrete acid mucopolysaccharide, glycoprotein or both. Cells of all the midgut regions are capable of absorption which is carried out mainly by the anterior midgut and caeca. Midgut cells of Balanus balanoides (L.) show a seasonal variation in the distribution of intracellular lipid droplets. Midgut cells rest on an elastic basal lamina and secrete a peritrophic membrane which contains mucopolysaccharide and protein. Cells of the stratum perintestinale connect with the midgut epithelial cells via cell processes which probably translocate absorbed materials. Glycoprotein globules and lipid droplets accumulate in the body parenchyma of B. balanoides and are transported to the ovaries to form yolk (glycolipovitellin). The pancreatic gland cells of all barnacles are active secretory cells secreting proteinaceous material (probably digestive enzymes).     

The fine structure of the digestive system of Daphnia pulex (Crustacea: Cladocera).

The alimentary canal of Daphnia pulex consists of a tube-shaped foregut, a midgut (mesenteron) with an anterior pair of small diverticula, and a short hindgut. The foregut and hindgut are structurally similar. Each is formed by a low cuboidal epithelium 5 mum tall and lined with a chitinous intima. The midgut wall consists of a simple epithelium resting on a thick beaded basal lamina which is surrounded by a spiraling muscularis. Anteriorly the midgut cells are columnar in shape being 30 mum in height each having a basal nucleus, anteriorly concentrated mitochondria and in apical border of long thin microvilli. Posteriorly the midgut cells become progressively shorter so that in the posteriormost region of the midgut the cells are 5 mum tall and cuboidal in shape. The microvilli concomitantly become shorter and thicker. All mesenteron cells contain the usual cytoplasmic organelles. The paired digestive diverticula are simple evaginations of the midgut. The wall of each consists of a simple epithelium of cuboidal cells 25 mum in height, each with a brushed border of long thin microvilli. Enzyme secretion appears to be holocrine in mode and not confined to any one region of the mesenteron though definitely polarized anteriorly. The thin gut muscularis encircles the entire length of the midgut and caeca. Thick and thin filaments appear to be in a 6:1 ratio.