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…     

麝甲状腺超微结构和甲状腺激素的合成与释放研究

通过对麝甲状腺的超微结构观察,认为麝甲状腺滤泡上皮细胞所合成的甲状腺球蛋白,可由粗面内质网囊泡（ＲＥＲＶ）和由粗面内质网（ＲＥＲ）与高尔基器形成的分泌泡二条途径直接进入滤泡腔。经微吞饮作用,由胶质小泡将滤泡腔中胶体再摄入滤泡上皮细胞,同溶酶体融合,分解产生甲状腺激素。     

麝甲状腺超微结构的甲状腺激素的合成与释放研究

通过对麝甲状腺的超微结构观察,认为麝甲状腺滤泡上皮细胞所合成的甲状腺球蛋白,可由粗面内质网裹泡和由粗面内质网与高尔基器形成的分泌泡二条途径直接进入泡泡腔,经微吞饮作用,由胶质小泡将滤泡腔中体再摄入滤泡上皮细胞,同溶酶体融合,分解产生甲状腺激素。     

玉米幼苗根不同发育区细胞中高尔基体的变化

玉米根细胞的三个发育区——分裂区、延伸区和成熟区高尔基体的变化:分裂区先由部分内质网碎片转化为潴泡,再由潴泡叠加构成具六个潴泡结构的高尔基器;延伸区高尔基器进行大量合成分泌物质,使大部分潴泡变成分泌泡而排出细胞外,导致高尔基器大量减少;成熟区高尔基器相当少,分泌能力一般。     

久效磷对中国对虾细胞超微结构的影响Ⅲ.对鳃的毒性效应

对中国对虾鳃细胞超微结构的透射电镜观察结果表明 ,经 0 .1 0mg·L- 1 久效磷处理的中国对虾 ,鳃丝细胞的内质网水肿、扩张和囊泡化 ,粗面内质网膜上的核糖体颗粒大量脱落 ;高尔基膜囊轻微水肿 ,高尔基小泡水肿扩张 ,严重者破裂 ;线粒体的内嵴膨胀 ,局部瓦解乃至解体 ;鳃丝上皮细胞角质层变性脱落 ,核膜水肿 ,部分溶解 .     

慈菇匍匐茎中分泌道的初步研究

慈茹匍蔔茎的分泌道是裂生的胞间道,分布于匍匐茎的基本组织中。单个分泌道原始细胞起始于离茎端约1毫米处的基本分生组织中,原始细胞经分裂形成5—7个上皮细胞包围着中央的裂生腔隙,成为管道系统。上皮细胞无鞘细胞包围。上皮细胞中高尔基体和内质网发达,并溢出小囊泡向着分泌道腔隙面壁的质膜附近迁移,乳汁中亦存在大量完整的小囊泡。上皮细胞和外围薄壁细胞之间的壁层具有大量胞间连丝,小囊泡和内质网的膜结构与胞间连丝末端相接,同时可见上皮细胞的质膜在数处反折内陷,形成袋状结构,在与上皮细胞相对的薄壁细胞内也有同样现象出现,袋状结构内含小形颗粒或囊泡,并在结构上显示出上皮细胞与相邻薄壁细胞间存在着活跃的物质交流。由此认为。代谢物质以整体小囊泡的形式经胞间连丝或内陷的质膜向分泌道迁移是物质运输和分泌的可能方式之一。在电镜下观察,液泡中的积聚物与乳汁十分相似,液泡可能是乳汁的贮存场所之一。     

水貂卵母细胞发育过程中卵泡细胞的微细结构研究

本文应用光镜,电镜及组织化学方法对水貂卵丘形成过程进行了研究。结果表明,在发育过程中,卵泡细胞内含有一些圆形线粒体,许多单个粗面内质网囊池和丰富的核糖体,高尔基复合体罕见,当卵泡细胞变成单层柱状时,细胞内开始出现成团的微丝及一些直径１－２μｍ的厚壁泡。在卵泡细胞膜上可见到胞吐小泡以及细胞间夹有透明带物质,表明卵泡细胞可能参与透明带的形成,随着卵泡腔的形成,卵泡细胞开始出现含中性脂肪及磷脂的颗粒,卵     

浙贝母鳞片衰退过程的超微结构研究

通过光镜和电镜手段观察了浙贝母（Ｆｒｉｔｉｌｌａｒｉａ ｔｈｕｎｂｅｒｇｉｉＭｉｑ．）鳞片的衰退过程．开始时,近轴面表皮附近的几层薄壁细胞首先瓦解,形成一条清晰的破碎细胞带．细胞内含物的降解过程是主动有序的．高尔基体和内质网产生许多囊泡,囊泡在细胞内含物的降解和降解产物的运输过程中起着重要的作用．细胞间丰富的胞间连丝是胞间物质运输的良好通道     

西瓜种子发育和萌发过程中子叶细胞超微结构的变化

西瓜种子子叶内贮存物质开始积累时,细胞质内有大量核糖体、质体、线粒体,内质网片段和囊泡,种子脱水期至成熟期,细胞器的数量减少,成熟种子子叶细胞的细胞壁不连续,几乎观察不到细胞器的存在,种子萌发过程中内质网,线粒体,质体的数目逐渐增多,叶肉细胞的质体发育成叶绿体,种子形成过程中,在子叶细胞大液泡分隔的同时,膨胀的内质网囊泡内积累蛋白质（直径0.1-0.4μm),这些小的蛋白质球体最终进入液泡形成大的蛋白体（直径1-3μm);萌发种子贮存蛋白质被水解的同时,一些脂体进入液泡并被分解,同时液泡融合;脂类物质开始积累的时间早于蛋白质,积累的量较蛋白质多,但在萌发种子中被彻底水解的时间晚于蛋白质,淀粉粒的数量在种子形成时减少,种子萌发时在表皮细胞和叶肉细胞内都重新合成。     

荔枝雄花性别决定过程中细胞超微结构的变化

荔枝雄花雌蕊原基在大孢子母细胞减数分裂后开始衰退.内质网历经增生扩展,穿壁相连,同心缠绕,多条平行弯曲,不规则堆叠.内质网和高尔基体产生许多囊泡,囊泡在细胞内含物的降解和运输过程中起着重要的作用.线粒体在雌蕊原基细胞衰败的前、中期数量增加,后期分批降解.过氧化物酶体在雌蕊原基细胞衰败的中期紧挨核短暂出现.细胞核的染色质凝集断裂;核周腔扩大,形成胀泡;染色质趋边,外泄.细胞原生质表现出有序的、在膜包裹下的降解,首先是核糖体,而后依次是:过氧化物酶体、内质网、高尔基体、线粒体、核.雌蕊原基的衰败历程可能是一种程序性细胞死亡的过程.     

CYTOCHALASIN B INFLUENCES DICTYOSOMAL VESICLE PRODUCTION AND MORPHOGENESIS IN THE DESMID EUASTRUM1

Cytochalasin B (CB) applied to young developing cells of the desmid Euastrum oblongum Ralfs ex Ralfs, at concentrations that do not entirely inhibit cytoplasmic streaming, retarded cell growth and caused malformations of cell shape. While the basic symmetry of the cell was maintained, only the first indentations were formed and the cell body appeared to be swollen. Electron microscopic investigations revealed that vesicle production at the dictyosomes was disturbed by cytochalasin. In contrast to untreated control cells, where vesicles with electron-dense contents (“dark vesicles”) were formed during primary wall formation, vesicles pinched off by the dictyosomes during CB treatment exhibited an “empty” appearance. These vesicles, which correspond to the “dark vesicles” in size, were accumulated around the dictyosomes without being transported to the plasma membrane and were frequently connected to the trans-cisternae of the Golgi bodies. We speculate that CB may influence the transfer of products from the endoplasmic reticulum (ER) to the dictyosomes via transition vesicles, which results in a disturbed vesicle production at the Golgi bodies. CB also causes a shift in ER and dictyosome distribution. Moreover, a cortical actin system appears to be involved in the cell shaping of Euastrum. The arrangement of microtubules around the nucleus is not affected by the drug.     

花生胚乳细胞化的超微结构观察

花生（ＡｒａｃｈｉｓｈｙｐｏｇｅａｅＬ．）心形胚期的胚乳游离核多瓣裂,或具长尾状结构。胚乳细胞质内有大量线粒体、质体、高尔基体、小泡及少量内质网。中央细胞壁有壁内突。球胚及心形胚期常见胚乳瘤。心形胚晚期,胚乳开始细胞化,胚乳细胞壁形成有３种方式,分别存在于不同的胚珠中：（１）从胚囊壁产生自由生长壁形成初始垂周壁,具有明显的电子密度深的中层,其生长主要靠末端的高尔基体小泡及内质网囊泡的融合。两相邻的自由生长壁末端或其分枝末端相连形成胚乳细胞。（２）核有丝分裂后产生细胞板,细胞板向外扩展并可分枝。间期的非姊妹核间也观察到形成了细胞板。小泡与微管参与细胞板的扩展,高尔基体和内质网是小泡的主要来源。细胞板的扩展末端相互连接,形成胚乳细胞的前身。小泡继续加入细胞板的组成,以后形成胚乳细胞壁。（３）胚乳细胞质中,出现一些比较大的不规则形的片段性泡状结构,它们可能来源于高尔基体小泡,这些片段性泡状结构随机相连形成细胞壁,未见微管参与。胚乳细胞外切向壁及经向壁上有壁内突。     

Ultrastructural studies of a vesicle system associated with endoplasmic reticulum in exo-erythrocytic forms of Plasmodium berghei

Fine structural studies of a specialized vesicle system associated with the endoplasmic reticulum (ER) of exo-erythrocytic Plasmodium berghei suggest that this system may be the equivalent of a Golgi apparatus. Patches of ER, randomly distributed in the cytoplasm of developing parasites, are formed of smooth and ribosome-studded cisternae intermingled with each other. The vesicle systems are located between as well as at the edges of ER aggregates and appear to be in different stages of budding from the cisternae. Prolonged osmication reveals distinct staining of the nuclear envelope and ER of the parasites as well as part of the Golgi apparatus of the hepatocytes. However, the small vesicles associated with the parasite's ER are unstained, as are the coated vesicles in the Golgi region of the liver cell. These sites in the parasite cytoplasm seem comparable to the concave surface of the Golgi apparatus in liver cells. The pinched-off vesicles fuse with others to form the prominent peripheral vacuolization characteristic of the nearly mature exoerythrocytic form. The formation of these peripheral vacuoles and their subsequent fusion with the parasite membrane may be an exocytosis mechanism supplying the rapidly expanding parasite with new plasma membrane material.     

Ultrastructural Studies of a Vesicle System Associated with Endoplasmic Reticulum in Exo-Erythrocytic Forms of Plasmodium berghei1

ABSTRACT. Fine structural studies of a specialized vesicle system associated with the endoplasmic reticulum (ER) of exo-erythrocytic Plasmodium berghei suggest that this system may be the equivalent of a Golgi apparatus. Patches of ER, randomly distributed in the cytoplasm of developing parasites, are formed of smooth and ribosome-studded cisternae intermingled with each other. The vesicle systems are located between as well as at the edges of ER aggregates and appear to be in different stages of budding from the cisternae. Prolonged osmication reveals distinct staining of the nuclear envelope and ER of the parasites as well as part of the Golgi apparatus of the hepatocytes. However, the small vesicles associated with the parasite's ER are unstained, as are the coated vesicles in the Golgi region of the liver cell. These sites in the parasite cytoplasm seem comparable to the concave surface of the Golgi apparatus in liver cells. The pinched-off vesicles fuse with others to form the prominent peripheral vacuolization characteristic of the nearly mature exo-erythrocytic form. The formation of these peripheral vacuoles and their subsequent fusion with the parasite membrane may be an exocytosis mechanism supplying the rapidly expanding parasite with new plasma membrane material.     

Carbon tetrachloride suppresses ER-Golgi transport by inhibiting COPII vesicle formation on the ER membrane in the RLC-16 hepatocyte cell line

Carbon tetrachloride (CCl₄) causes hepatotoxicity in mammals, with its hepatocytic metabolism producing radicals that attack the intracellular membrane system and destabilize intracellular vesicle transport. Inhibition of intracellular transport causes lipid droplet retention and abnormal protein distribution. The intracellular transport of synthesized lipids and proteins from the endoplasmic reticulum (ER) to the Golgi apparatus is performed by coat complex II (COPII) vesicle transport, but how CCl₄ inhibits COPII vesicle transport has not been elucidated. COPII vesicle formation on the ER membrane is initiated by the recruitment of Sar1 protein from the cytoplasm to the ER membrane, followed by that of the COPII coat constituent proteins (Sec23, Sec24, Sec13, and Sec31). In this study, we evaluated the effect of CCl₄ on COPII vesicle formation using the RLC-16 rat hepatocyte cell line. Our results showed that CCl₄ suppressed ER-Golgi transport in RLC-16 cells. Using a reconstituted system of rat liver tissue-derived cytoplasm and RLC-16 cell-derived ER membranes, CCl₄ treatment inhibited the recruitment of Sar1 and Sec13 from the cytosolic fraction to ER membranes. CCl₄-induced changes in the ER membrane accordingly inhibited the accumulation of COPII vesicle-coated constituent proteins on the ER membrane, as well as the formation of COPII vesicles, which suppressed lipid and protein transport between the ER and Golgi apparatus. Our data suggest that CCl₄ inhibits ER-Golgi intracellular transport by inhibiting COPII vesicle formation on the ER membrane in hepatocytes.     

ELECTRON MICROSCOPIC STUDIES ON ACHROSOME FORMATION IN THE COCKROACH, BLATTELLA GERMANICA

The development of achrosomes in spermiogenesis of Blattella germanica was studied by electron microscopy. Achrosomes consist of an achrosomal vesicle originating from Golgi vesicles and an axial rod composed of fine fibrils.
The achrosomal vesicle, formed at the mature face of the Golgi body, migrates to the anterior of the nucleus, where it later becomes the front structures of sperm head. After attachment to the nucleus, the achrosomal vesicle changes from a round to a tapering shape, passing through a coneshape phase. During these changes, the axial rod develops in the hollow formed by indentations of adjacent parts of the achrosomal vesicle and the nucleus.
The cisternae of the Golgi body concerned with formation of the achrosomal vesicle, are made by pinching off small vesicles from both the ER and the nuclear envelope.     

Gastric mucosal cell homeostatic physiome. Critical role of ER-initiated membranes restitution in the fidelity of cell function renewal.

Homeostatic cell physiology is preserved through the fidelity of the cell membranes restitution. The task is accomplished through the assembly of the precisely duplicated segments of the cell membranes, and transport to the site of their function. Here we examined the mechanism that initiates and directs the restitution of the intra- and extracellular membranes of gastric mucosal cell. The homeostatic restitution of gastrointestinal epithelial cell membrane components was investigated by studying the lipidomic processes in endoplasmic reticulum (ER) and Golgi. The biomembrane lipid synthesis during the formation of transport vesicles in the systems containing isolated organelle and the cell-specific cytosol (Cyt) from rat gastric mucosal epithelial cells was assessed. The results revealed that lipids of ER transport vesicle and the transmembrane and intravesicular cargo are delivered en bloc to the point of destination. En bloc delivery of proteins, incorporated into predetermined in ER lipid environment, ensures fidelity of the membrane modification in Golgi and the restitution of the lipid and protein elements that are consistent with the organelle and the cell function. The mechanism that maintains apical membrane restitution is mediated through the synthesis of membrane segments containing ceramide (Cer). The Cer-containing membranes and protein cargo are further specialized in Golgi. The portion of the vesicles destined for apical membrane renewal contains glycosphingolipids and phosphatidylinositol 3-phosphate. The vesicles containing phosphatidylinositol 4-phosphate are directed to endosomes. Our findings revealed that the preservation of the physiological equilibrium in cell structure and function is attributed to (1) a complete membrane segment synthesis in ER, (2) its transport in the form of ER-transport vesicle to Golgi, (3) the membrane components-defined maturation of lipids and proteins in Golgi, and (4) en bloc transfer of the new segment of the membrane to the cell apical membrane or intracellular organelle.     

Efficient transport of Semliki Forest virus glycoproteins through a Golgi complex morphologically altered by Uukuniemi virus glycoproteins.

In infected BHK21 cells, the glycoproteins G1 and G2 of a temperature-sensitive mutant (ts12) of Uukuniemi virus (UUK) accumulate at 39 degrees C in the Golgi complex (GC) causing an expansion and vacuolization of this organelle. We have studied whether such an altered Golgi complex can carry out the glycosylation and transport to the plasma membrane (PM) of the Semliki Forest virus (SFV) glycoproteins in double-infected cells. Double-immunofluorescence staining showed that approximately 90% of the cells became infected with both viruses. Almost the same final yield of infectious SFV was obtained from double-infected cells as from cells infected with SFV alone. The rate of transport from the endoplasmic reticulum (ER) via the GC to the plasma membrane of the SFV glycoproteins was analysed by immunofluorescence, surface radioimmunoassay and pulse-chase labeling followed by immunoprecipitation, endoglycosidase H digestion and SDS-PAGE. The results showed that: the SFV glycoproteins were readily transported to the cell surface in double-infected cells, whereas the UUK glycoproteins were retained in the GC; the transport to the PM was retarded by approximately 20 min, due to a delay between the ER and the central Golgi; E1 of SFV appeared at the PM in a sialylated form. These results indicate that the morphologically altered GC had retained its functional integrity to glycosylate and transport plasma membrane glycoproteins.     

Diacylglycerol is required for the formation of COPI vesicles in the Golgi-to-ER transport pathway

Diacylglycerol is necessary for trans-Golgi network (TGN) to cell surface transport, but its functional relevance in the early secretory pathway is unclear. Although depletion of diacylglycerol did not affect ER-to-Golgi transport, it led to a redistribution of the KDEL receptor to the Golgi, indicating that Golgi-to-ER transport was perturbed. Electron microscopy revealed an accumulation of COPI-coated membrane profiles close to the Golgi cisternae. Electron tomography showed that the majority of these membrane profiles originate from coated buds, indicating a block in membrane fission. Under these conditions the Golgi-associated pool of ARFGAP1 was reduced, but there was no effect on the binding of coatomer or the membrane fission protein CtBP3/BARS to the Golgi. The addition of 1,2-dioctanoyl-sn-glycerol or the diacylglycerol analogue phorbol 12,13-dibutyrate reversed the effects of endogenous diacylglycerol depletion. Our findings implicate diacylglycerol in the retrograde transport of proteins from Golgi to the ER and suggest that it plays a critical role at a late stage of COPI vesicle formation.     

Coupled ER to Golgi Transport Reconstituted with Purified Cytosolic Proteins

A cell-free vesicle fusion assay that reproduces a subreaction in transport of pro-α-factor from the ER to the Golgi complex has been used to fractionate yeast cytosol. Purified Sec18p, Uso1p, and LMA1 in the presence of ATP and GTP satisfies the requirement for cytosol in fusion of ER-derived vesicles with Golgi membranes. Although these purified factors are sufficient for vesicle docking and fusion, overall ER to Golgi transport in yeast semi-intact cells depends on COPII proteins (components of a membrane coat that drive vesicle budding from the ER). Thus, membrane fusion is coupled to vesicle formation in ER to Golgi transport even in the presence of saturating levels of purified fusion factors. Manipulation of the semi-intact cell assay is used to distinguish freely diffusible ER- derived vesicles containing pro-α-factor from docked vesicles and from fused vesicles. Uso1p mediates vesicle docking and produces a dilution resistant intermediate. Sec18p and LMA1 are not required for the docking phase, but are required for efficient fusion of ER- derived vesicles with the Golgi complex. Surprisingly, elevated levels of Sec23p complex (a subunit of the COPII coat) prevent vesicle fusion in a reversible manner, but do not interfere with vesicle docking. Ordering experiments using the dilution resistant intermediate and reversible Sec23p complex inhibition indicate Sec18p action is required before LMA1 function.