不同年龄大鼠小脑浦肯野细胞超微结构的变化

对不同年龄雄性Ｗｉｓｔａｒ大鼠小脑蚓剖皮质浦肯野细胞的超微结构进行了观察。结果表明,随年龄增神经内的细胞器和内涵物发生了明显变化。浦肯野细胞内粗面内质网、高尔基复合体等细胞器数量有不同程度减少;微管增加;粗面内质网排列失序,网腔扩张;高尔基器排列紊乱,囊腔扩张;线粒体扩张或固缩,     

显著六鞭毛虫超微结构的观察

作者对显著六鞭毛虫作了超微结构的观察。两个胞核平行,靠近或稍旋转。两根Ｒ鞭毛的外侧具有发达的粗内质网。近内质网处的胞质向体外突出成两个小突起。胞质内具线粒体,高尔基体等胞器。     

高原鼠兔松果体超微结构的研究

本文采用光镜和透射电镜对高原鼠兔松果体的形态结构进行了观察,并对其结构与功能的关系怍了初步探讨：1． 高原鼠兔的松果体与其他哺乳动物的基本相似, 包括深、浅两部分, 两部分的细胞构筑及其形态基本一致,主要由松果体细胞、胶质细胞、神经细胞、微细血管和神经纤维组成。松果体细胞有明、暗两种,两种细胞胞质内均有丰富的线粒体、高尔基复合体、粗面和滑面内质网,以及游离核糖体,还可见极少数微管和脂滴等。2． 松果体细胞内囊泡、微管和突触带的数量与细胞的分泌功能密切相关。3． 松果体分泌物主要通过二种方式释放：(1)通过扩散和胞吐作用,将分泌物释放到细胞外或血管周隙;(2)分泌物直接进入第三脑室。     

几种淡水鱼的胃腺细胞显微与超微结构的研究

尼罗非鲫的胃腺细胞和一般硬骨鱼类的泌酸胃酶细胞结构不同,属典型的泌酸细胞,与哺乳动物的壁细胞十分相似,细胞内充满微管泡系和线粒体,但是没有发现胃蛋白酶原颗粒,粗面内质网也极少,乌鳢,鲇和黄颡鱼的胃腺细胞则为典型的泌酸酶原细胞,除有微管泡系和线粒体外,还有丰富的胃蛋白酶原颗 和粗面内质网,用显示盐酸的Western方法证明这两类胃腺细胞都能分泌盐酸,但对检测色氨酸的Adams方法,两者都呈阴性反应,未能证明乌鳢胃细胞中胃蛋白酶原的存在,可能乌鳢的胃蛋白酶成分中色氨酸的含量不占多数,故未能检出。这两类胃腺细胞结构和功能的不同,与整个消化道结构的差别相一致,可能与它们的食性不同有关。微管泡系是两类胃腺细胞共有的结构,是泌酸的结构基础,由一系列短管的囊泡组成,在鱼类中,泌酸过程可能有顶浆分泌和局部分泌两种形式,泌酸活动中细胞顶膜,微管泡系以及高尔基体之间膜的转移关系和泌酸形式有关。     

促红细胞生成素的分泌过程三维模式图

DNA经转录得到前体 m RNA,进一步剪切加工修饰得到成熟的 m RNA。核糖核蛋白体与 m RNA串连成多聚核糖核蛋白体 ,并通过信号识别颗粒及其受体结合于粗面内质网膜上 ,新合成的蛋白质进入内质网腔 ,经过加工修饰 ,以转运小泡的形式 ,运输到高尔基复合体。高尔基复合体由大囊泡、小囊泡和扁平囊组成 ,呈弯曲圆盘状。凸面称形成面或顺面 ,朝向胞核 ,凹面称分泌面或反面 ,朝向细胞表面 ,小囊泡多位于顺面 ,由粗面内质网出芽而来 ,运送新合成的蛋白质到扁平囊中 ,并不断补充扁平囊的膜结构。蛋白质在囊腔中经进一步加工修饰 ,由扁平囊两端和…     

γ-微管蛋白研究进展

概述了近年来对γ-微管蛋白复合体结构、分子机制以及功能的研究进展.γ-微管蛋白是真核生物体内一种重要的保守性功能蛋白,以γ-微管蛋白小复合体和γ-微管蛋白环式复合体两种形式存在.通过γ-微管蛋白复合体结合蛋白定位于微管组织中心,参与微管的晶核起始以及有丝分裂纺锤体的组装等细胞功能.     

麝鼠泌香期香囊腺形态及组织结构的研究

麝鼠香囊腺由腺细胞、支持细胞和排香管组成。其分泌腺属复管泡状腺。发育初期的腺泡胞质内含有大量的粗面内质同、光滑内质网、高尔基复合体、中心粒和线粒体、香腺细胞间连接发达,桥粒、半桥粒广为分布。胞质内含有电子致密度高和电子致密度低的两种分泌颗粒。其分泌方式为顶浆分泌。     

中华蜜蜂工蜂蜡腺细胞的超微结构

本文描述了中华蜜蜂(Apis cerana)成体工蜂蜡腺细胞的超微结构.通过电镜观察发现蜡腺细胞具有许多质膜内陷形成的管腔,作为蜂蜡或其前体物的输送通道.细胞质中富含线粒体及粗面内质网,细胞核为不规则的形状,细胞质中还含有少量溶酶体,微管和微丝等结构.     

中华稻蝗卵子卵黄发生期超微结构研究

利用透射电镜研究了中华稻蝗Oxya chinesis卵子发生中卵黄发生期的超微结构.卯黄发生初期,滤泡上皮细胞胞质内出现大量粗面内质网及线粒体等细胞器,可能与为卵母细胞提供营养有关.卵黄发生期卵母细胞胞质内卵黄球逐渐增多,它也许有多种来源.观察到环形片层结构,并讨论了其可能功能.     

新疆医科大学基础医学院组织胚胎学教研室

目的:观察国人胚胎三叉神经节细胞分化及发育过程。方法:取水囊引产18-36周国人胎儿三叉神经节,HE染色及透射电镜观察。结果:18-20周胎儿三叉神经节神经元排列紧密,胞质少,可见到数量不多的线粒体,且其内几乎看不到嵴,其它细胞器少。25周时,线粒体嵴变长,粗面内质网雏形出现,有纵形小管出现;27周时可观察到成熟的高尔基复合体,32周后,线粒体、粗面内质网等细胞器发育趋于成熟。到33周电镜下可见溶酶体;36周时细胞内各种细胞器结构和功能基本完善。结论:人胚胎三叉神经节细胞发育过程中随胎龄增加,其结构和功能逐步完善,32～36周(8～9月)是细胞的分化发育重要时期。     

Ultrastructure of Mitosis and Cytokinesis In the Colorless Flagellate Katablepharis Ovalis Skuja

ABSTRACT. Mitosis and cytokinesis in Katablepharis ovalis , a colorless flagellate, was investigated. Two new flagella are produced prior to prophase, resulting in a motile quadriflagellate cell during mitosis. the inner array of microtubules of the feeding apparatus disappears before prophase begins. the nuclear envelope disperses during prophase, apparently being converted into rough endoplasmic reticulum. the chromatin condenses and the nucleolus disperses with spindle microtubules appearing oriented perpendicular to the longitudinal axis of the cell. At metaphase, the chromatin is condensed as a single disc-shaped mass and rough endoplasmic reticulum flanks the chromatin mass on each side. Groups of spindle microtubules pass through tunnels in the rough endoplasmic reticulum and through electron-translucent areas of the chromatin. the spindle microtubules end at a number of minipoles in the cytoplasm. Vesicles, ribosomes, mitochondria and endoplasmic reticulum migrate among the spindle microtubules. There is no polar body or any electrondense area associated with the spindle poles. the basal bodies of the flagella remain attached to the axonemes and do not participate in mitosis. In anaphase, the chromatin separates and migrates to the poles. During telophase, the nuclear envelope reforms from the rough endoplasmic reticulum and the nucleoli reappear. the spindle microtubules are persistent during telophase. Cytokinesis occurs by longitudinal fission, starting at the anterior end and progressing posteriorly. Cytokinesis may be driven by elongation of the spindle microtubules since there is no visible structure associated with the furrowing.     

Microtubules and the organization of the Golgi complex

Electron microscopic and cytochemical studies indicate that microtubules play an important role in the organization of the Golgi complex in mammalian cells. During interphase microtubules form a radiating pattern in the cytoplasm, originating from the pericentriolar region (microtubule-organizing centre). The stacks of Golgi cisternae and the associated secretory vesicles and lysosomes are arranged in a circumscribed juxtanuclear area, usually centered around the centrioles, and show a defined orientation in relation to the rough endoplasmic reticulum. Exposure of cells to drugs such as colchicine, vinblastine and nocodazole leads to disassembly of microtubules and disorganization of the Golgi complex, most typically a dispersion of its stacks of cisternae throughout the cytoplasm. These alterations are accompanied by disturbances in the intracellular transport, processing and release of secretory products as well as inhibition of endocytosis. The observations suggest that microtubules are partly responsible for the maintenance and functioning of the Golgi complex, possibly by arranging its stacks of cisternae three-dimensionally within the cell and in relation to other organelles and ensuring a normal flow of material into and away from them. During mitosis, microtubules disassemble (prophase) and a mitotic spindle is built up (metaphase) to take care of the subsequent separation of the chromosomes (anaphase). The breaking up of the microtubular cytoskeleton is followed by vesiculation of the rough endoplasmic reticulum and partial atrophy, as well as dispersion of the stacks of Golgi cisternae. After completion of the nuclear division (telophase), the radiating microtubule pattern is re-established and the rough endoplasmic reticulum and the Golgi complex resume their normal interphase structure. This sequence of events is believed to fulfil the double function to provide tubulin units and space for construction of the mitotic spindle and to guarantee an approximately equal distribution of the rough endoplasmic reticulum and the Golgi complex on the two daughter cells.     

毛竹茎纤维次生壁形成过程的超微结构观察

利用透射电镜观察了毛竹（Ｐｈｙｌｌｏｓｔａｃｈｙｓ ｐｕｂｅｓｃｅｎｓ Ｍａｚｅｌ）茎纤维发育过程中次生壁的形成过程。纤维发育早期,细胞具有较大的细胞核和核仁;细胞质浓稠,具有核糖体、线粒体和高尔基体等细胞器。随着纤维次生壁的形成,细胞壁加厚,细胞质变得稀薄,内质网和高尔基体的数量明显增加,并且两者共同参与了运输小泡的形成;在质膜内侧可观察到大量周质微管分布。随着次生壁的进一步加厚及木质化,细胞壁     

Immuno-electron-microscopic identification of O-antigen-bearing oligodendroglial cells in vitro

Summary Monoclonal antibodies to cell-surface antigens of oligodendrocytes (Sommer and Schachner 1980; Schachner et al. 1980) were used to identify this cell type by immuno-electron microscopy in monolayer cultures of fetal and early postnatal mouse cerebellum. The ultrastructural features of antigen-positive cells confirm that they are immature and mature oligodendrocytes, but not neurons, astrocytes or fibroblasts or fibroblast-like cells. Type I oligodendrocytes are the immature ones with a relatively large amount of moderately electron-lucent cytoplasm, clusters of ribosomes and complex networks of rough endoplasmic reticulum. Large numbers of mitochondria and microtubules, but not intermediate-sized filaments are seen in these cells. They comprise more than 90% of all 0-antigen-positive cells. Type II cells comprise only approximately 5% of all 0-antigen-positive cells. They are characterized by a limited amount of electron-dense cytoplasm, which appears more compact and granular than in type I cells. The rough endoplasmic reticulum is distributed evenly throughout the cytoplasm. Microtubules and mitochondria are present, but more difficult to distinguish due to the compactness of the cytoplasm. Type II cells display the more mature ultrastructural features of oligodendrocytes.     

THE FINE STRUCTURE OF DIFFERENTIATING XYLEM ELEMENTS

Differentiating xylem elements of Avena coleoptiles have been examined by light and electron microscopy. Fixation in 2 per cent phosphate-buffered osmium tetroxide and in 6 per cent glutaraldehyde, followed by 2 per cent osmium tetroxide, revealed details of the cell wall and cytoplasmic fine structure. The localized secondary wall thickening identified the xylem elements and indicated their state of differentiation. These differentiating xylem elements have dense cytoplasmic contents in which the dictyosomes and elements of rough endoplasmic reticulum are especially numerous. Vesicles are associated with the dictyosomes and are found throughout the cytoplasm. In many cases, these vesicles have electron-opaque contents. "Microtubules" are abundant in the peripheral cytoplasm and are always associated with the secondary wall thickenings. These microtubules are oriented in a direction parallel to the microfibrillar direction of the thickenings. Other tubules are frequently found between the cell wall and the plasma membrane. Our results support the view that the morphological association of the "microtubules" with developing cell wall thickenings may have a functional significance, especially with respect to the orientation of the microfibrils. Dictyosomes and endoplasmic reticulum may have a function in some way connected with the synthetic mechanism of cell wall deposition.     

Ultrastructural Study of Secondary Wall Formation in the Stem Fiber of Phyllostachys pubescens

Ultrastructural changes in secondary wall formation of Phyllostachys pubescens Mazel fiber were investigated with transmission electron microscopy. Fiber developed initially with the elongation of cells containing ribosomes, mitochondria and Golgi bodies in the dense cytoplasm. During the wall thickening, the number of rough endoplasmic reticulum and Golgi bodies increased apparently. There were two kinds of Golgi vesicles, together with the ones from endoplasmic reticulum formed transport vesicles. Many microtubules were arranged parallel to the long axis of the cell adjacent to the plasmalemma. Along with the further development of fiber, polylamellate structure of the secondary wall appeared, with concurrent agglutination of chromatin in the nucleus, swelling and disintegration of organelles, while cortical microtubules were still arranged neatly against the inner side of plasmalemma. Lomasomes could be observed between the wall and plasmalemma. The results indicated that the organelles, such as Golgi bodies together with small vesicles, rough endoplasmic reticulum and lomasomes, played the key role in the thickening and lignification of the secondary wall of bamboo fiber, though cortical microtubules were correlative with the process as well.     

Structure of taste buds in foliate papillae of the rhesus monkey, Macaca mulatta

Taste buds in foliate papillae of the rhesus monkey were examined by electron microscopy. Three distinct cell types were identified. Type I cells were narrow elongated cells containing an oval nucleus, bundles of intermediate filaments, several Golgi bodies, and characteristic apical membrane-bounded dense granules. These cells exhibited morphological variations: some had a moderately dense cytoplasm, perinuclear free ribosomes, and flattened sacs of rough endoplasmic reticulum; others had a more lucent cytoplasm, dilated irregular rough endoplasmic reticulum, lysosome-like dense bodies, and lipid droplets. Type II cells typically contained a spherical, pale nucleus, a prominent nucleolus, supranuclear and infranuclear Golgi bodies, mitochondria with tubular cristae, and one or two centrioles. This cell type, too, showed some variation in the relative amounts of ribosomes and smooth endoplasmic reticulum, which varied inversely with each other. Type III cells were characterized by a clear apical cytoplasm essentially devoid of ribosomes and containing microtubules. In a few type III cells, the peri- and infranuclear regions contained many ribosomes and some rough endoplasmic reticulum. In most Type III cells, there were large numbers of dense and clear vesicles in the peri- and infranuclear regions; some of the vesicles were grouped in synapse-like arrangements with adjacent nerves. The morphological variations exhibited by all three cell types could be accounted for by age differences in each of the cells. This would be consistent with the notion that cell renewal occurs in each of the three cell populations.     

The arrangement of the Golgi complex beads is not controlled by the cytoskeleton

Exposure of insect fat body to treatments which disrupt microtubules (colchicine, vinblastine sulfate and cold treatment) blocks intracellular transport between the Golgi complex and the plasma membrane but does not affect Golgi complex bead rings or transport from rough endoplasmic reticulum to the Golgi complex. Drugs which disrupt microfilaments (cytochalasins B and D) do not affect the bead rings or intracellular transport of secretory proteins at any level. Thus, intracellular transport between the rough endoplasmic reticulum and the Golgi complex and the arrangement of the beads in rings are both independent of the cytoskeleton. The ring arrangement is presumably maintained by interconnection(s) with rough endoplasmic reticulum membrane.     

On the ultrastructure of differentiating secondary xylem in willow

Summary Studies of differentiating xylem inSalix fragilis L. show the immediate cambial derivatives to be ultrastructurally similar. The Golgi apparatus is important at all stages of wall synthesis, possibly producing (amongst other substances) hemicellulose material which is carried to the wall in vesicles or multivesicular bodies. The endoplasmic reticulum also contributes one or more components to the developing wall: at some stages during differentiation the endoplasmic reticulum produces electron opaque bodies which appear to be guided towards the wall by microtubules. Compact structures formed from concentric membranes (myelin-like bodies) have been found joined to rough endoplasmic reticulum, but their presence is not explained.Two types of plasmalemma elaboration occur: invagination of the plasmalemma itself to form vesicles which may contain cytoplasmic material; and vesicles between the plasmalemma and cell wall which are the result of single vesicles or multivesicular bodies traversing the plasmalemma. Both systems provide a means for transporting cytoplasmic material across the plasmalemma.Microtubules have been seen associated with all vesicles derived from the cytoplasm which appear to be moving towards the wall. The presence of microtubules may generally be explained in terms of orientation of vesicles, even if they also happen coincidentally to parallel the supposed orientation of microfibrils in the wall itself. It is possible to resolve connections between the microtubules and the plasmalemma.     

Ultrastructure of epidermal glands in neotenic reproductives of the termite Prorhinotermes simplex (Isoptera: Rhinotermitidae)

The ultrastructure of epidermal glands in neotenic reproductives of Prorhinotermes simplex is described and their development is compared among young and old neotenics of both sexes. Secretory cells forming the epidermal gland are attached to the cuticle all over the body. The glands are formed by class 1 and class 3 secretory cells and corresponding canal cells with secretory function. Class 1 cells are sandglass-like and class 3 secretory units are located among them. Class 1 cells contain predominantly tubular endoplasmic reticulum, the major part represents the smooth and the minor the rough form. Numerous electron dense granules occur in the cytoplasm, they are always disintegrated prior to be released. Class 3 secretory cells contain a large amount of vacuoles, which are always lucent in males while newly produced vacuoles are dense in females. Dense vacuoles are frequently transformed into lucent ones before being released. Canal cells are locally equipped with microvilli. The conducting canal is surrounded by an electron dense secretion of regular inner structure. The cytoplasm of the canal cell contains numerous mitochondria, rough endoplasmic reticulum and a large proportion of microtubules. The young neotenic reproductives differ from the old ones by a lower amount of secretory products. Epidermal glands probably produce substances inhibiting the occurrence of superfluous reproductives.