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,     

线粒体在细胞凋亡中的介导作用

线粒体是细胞内产生能量的重要细胞器,被认为是细胞生存与死亡的调节中心。Bcl-2家族蛋白、内质网和溶酶体能引起线粒体膜通透性的改变,造成线粒体功能损伤,诱导细胞凋亡。本文主要综述线粒体在Bcl-2家族蛋白、内质网和溶酶体诱导细胞凋亡中作用的研究进展。     

蓖麻蚕前胸腺细胞超微结构的变化与蜕皮激素分泌活动的关系

本研究叙述蓖麻蚕Philosamia cythia ricini四龄及五龄幼虫前胸腺蜕皮激素分泌活动各不同时期所显示的腺细胞超微结构变化。从幼虫蜕皮后至进入眠期之间的腺细胞结构可分为三个时期,(1)不活动期:细胞核呈圆形,核内密布染色质及核仁,细胞质内有结构完整的线粒体、粗面及滑面内质网、核糖体和高尔基氏体;细胞外围的细胞间区内有许多小囊泡及多泡囊。(2)活动期:细胞结构变化为细胞核膜出现内陷、外突,形成波浪形的核周膜;线粒体变形,出现内嵴稀疏的空心线粒体。(3)激素释放期:细胞核变形,形成若干长短不一向外伸出的指状突,有些伸达细胞边缘;其余细胞器退化,其后仅余残缺的高尔基氏体,稀疏的核糖体,线粒体的内崤逐渐消失,成为空腔扩大的及空腔内藏“膜轮”的线粒体,和一些溶解体及大形“膜轮”。     

蓖麻蚕前胸腺细胞超微结构的变化与蜕皮激素分泌活动的关系

本研究叙述蓖麻蚕Philosamia cythia ricini四龄及五龄幼虫前胸腺蜕皮激素分泌活动各不同时期所显示的腺细胞超微结构变化.从幼虫蜕皮后至进入眠期之间的腺细胞结构可分为三个时期,(1)不活动期:细胞核呈圆形,核内密布染色质及核仁,细胞质内有结构完整的线粒体、粗面及滑面内质网、核糖体和高尔基氏体;细胞外围的细胞间区内有许多小囊泡及多泡囊.(2)活动期:细胞结构变化为细胞核膜出现内陷、外突,形成波浪形的核周膜;线粒体变形,出现内嵴稀疏的空心线粒体.(3)激素释放期:细胞核变形,形成若干长短不一向外伸出的指状突,有些伸达细胞边缘;其余细胞器退化,其后仅余残缺的高尔基氏体,稀疏的核糖体,线粒体的内崤逐渐消失,成为空腔扩大的及空腔内藏“膜轮”的线粒体,和一些溶解体及大形“膜轮”.     

线粒体损伤与动脉粥样硬化的研究进展

线粒体是细胞的能量工厂,是一种高度动态的双层膜细胞器,广泛分布于机体的多种细胞类型。很多研究表明,线粒体不仅在维持细胞能量稳态中起着重要作用,还参与对钙离子信号传递、细胞增殖和分化的调节。新近研究表明,线粒体损伤参与动脉粥样硬化的发生发展。本文综述了线粒体损伤与动脉粥样硬化的新进展,以期为动脉粥样硬化的有效防治提供新的策略和靶点。     

扩张莫尼茨绦虫(绦虫纲:圆叶目)卵黄细胞发育的超微结构

用透射电镜观察了扩张莫尼茨绦虫(Moniezia expansa)卵黄细胞发育的全过程。扩张莫尼茨绦虫卵黄细胞发育的规律为：(1)细胞体积不断增大;(2)质、核比不断增加而核体积几乎不发生改变,核表面从规则变为不规则,再由不规则变为规则,核内出现染色质浓缩成小块再分散的发育变化过程;(3)线粒体逐渐增多,发育不断完善;(4)粗面内质网及高尔基复合体出现由少到多,发育不断完善,再由多到少不断退化的变化;(5)由高尔基复合体组装的电子致密的小卵黄囊不断融合,至卵黄细胞成熟时仅有一卵黄囊,占据细胞大部分体积[动物学报49(2)：256—261,2003]。     

盐胁迫对芦苇细胞超微结构的影响

于2009年3月从辽宁盘锦双台河口湿地挖取芦苇根茎并人工桶栽,待缓苗成功后进行不同浓度的盐胁迫处理,用透射电镜观察芦苇细胞超微结构对不同盐度胁迫的响应,以明确芦苇细胞的耐盐性。结果表明:芦苇细胞可承受4.0%以下浓度的盐胁迫。当盐度介于0%～4.0%时,芦苇细胞膜系统开始遭到破坏,使芦苇细胞受损的膜结构发生局部内陷或萎缩变形,细胞器表面变得凹凸不平,或将功能丧失的细胞器清理出细胞外,出现破裂和解体,以响应结构损伤的膜系统的修复,使细胞功能得到修复;当盐度为4.0%时,芦苇细胞叶绿体、线粒体、细胞核等具有膜结构细胞器及细胞壁遭到破坏,造成芦苇细胞膜系统的不可逆损伤,使细胞正常的物质代谢与能量转换和信息传递无法完成,导致芦苇细胞新陈代谢过程的中断,芦苇细胞生命活动趋于停止;在8.0%浓度盐胁迫下,芦苇细胞膜系统结构完全消失解体,导致芦苇细胞直接死亡。     

苯并（a）芘对大弹涂鱼肝细胞超微结构的影响

在实验生态条件下,研究不同浓度苯并(a)芘(BaP)暴露下大弹涂鱼肝脏细胞超微结构的变化。结果表明,暴露于低浓度(0．5mg·L^-1)BaP 7d,大弹涂鱼肝脏细胞内的细胞器受到不同程度的损伤,其中线粒体和内质网是受BaP暴露影响最明显的细胞器,细胞核也受到不同程度的影响,细胞质中脂滴也增加;而暴露于高浓度(5mg·L^-1)BaP 2h,不仅是线粒体和内质网,几乎所有细胞器都受到严重影响,细胞器严重退化,细胞结构遭到严重破坏。研究结果证实,BaP可对大弹涂鱼肝细胞内多种细胞器造成损伤,并且BaP浓度越高,损伤程度越严重。     

间充质干细胞线粒体转移机制的研究进展

线粒体是真核生物母系遗传的多功能细胞器,不仅参与细胞能量代谢的调节,而且参与应激细胞的存活和命运决定。线粒体转移是间充质干细胞参与组织损伤修复和伤口愈合的重要机制之一。线粒体转移的途径有很多种,主要包括隧道纳米管、间隙连接通道、微泡、细胞融合以及胞吞作用等。多条信号传导通路可诱导隧道纳米管的形成,使线粒体从一个细胞转移到另一个细胞。多种应激信号,例如受损线粒体、线粒体DNA或线粒体其它产物的释放以及活性氧水平的升高等,都能引发线粒体从间充质干细胞转移到受体细胞。该文介绍线粒体从间充质干细胞转移到邻近应激细胞的现象,并讨论线粒体转移的可能机制及其在组织损伤等疾病治疗中的作用。     

竹红菌乙素(乙醇胺)修饰物对于鼠肝线粒体光敏损伤研究

竹红菌乙素与乙醇胺进行化学结构的修饰,可以得到红光性能更加优良的新型光敏剂(简称HB-E),为此,我们作了以下几方面的研究:1.对线粒体膜脂质过氧化损伤的光敏作用;2.对线粒体膜巯基蛋白光敏损伤;3.对ATP酶的失活;4.损伤机理的探讨;5.不同光敏剂光敏能力的对比;从以上研究可以看到HB-E光敏作用对于线粒体的损伤十分明显,从损伤的机理角度证明了氧自由基的作用是存在的,对于体系中产生超氧阴离子的来源认为并不是单线态氧的作用,而是HB-E自身产生自由基与氧反应的结果;所以说HB-E光敏作用中存在两种机制即:Ⅰ型和Ⅱ型并存;与其它光敏剂的光敏能力比较中明显大于血卟啉和亚甲兰。     

The function of the golgi complex in transitional epithelium. Synthesis of the thick cell membrane

The superficial squamous cells of rat transitional epithelium are limited, on their luminal face, by an asymmetrically thickened membrane. Patches of similar thick membrane are found in the walls of the Golgi cisternae and it is suggested that the Golgi system is the site of assembly of the thick plasma membrane. This implies membrane flow from the Golgi apparatus to the cell surface, and there is indirect evidence that the membrane is transported in the form of fusiform vacuoles, derived from the Golgi cisternae, which fuse with, and become part of, the free cell membrane. Uptake of injected Imferon shows that similar, large, thick-walled vacuoles may be formed by invagination of the free cell surface. Some of these vacuoles are subsequently transformed into multivesicular bodies and autophagic vacuoles. The formation of other large heterogeneous bodies is described, and some of these are shown to have acid phosphatase activity.     

大鼠睾丸间质细胞的自体吞噬活动

本文结合超微结构和细胞化学观察,研究大鼠睾丸间质细胞(Leydig细胞)中溶酶体的结??构与功能。观察结果表明,大鼠睾丸间质细胞中高尔基体非常发达,在高尔基体的成熟面存在着CMP酶阳性反应的GERL系统,说明这种细胞有不断产生溶酶体的能力。细胞化学结果也证实在睾丸间质细胞有较多的初级和次级溶酶体。睾丸间质细胞不仅有较多的溶酶体,而且还有相当数量的自噬小体,存在着活跃的自体吞噬活动。自噬小体的界膜来源于特化的光面内质网或高尔基体膜囊,包围的内容物主要是光面内质网和少量线粒体。当自噬小体与溶酶体融合后即成为自体吞噬泡,由于酶的消化作用,自体吞噬泡内的细胞器有一系列形态变化。根据CMP酶细胞化学反应,可以区分自噬小体和自体吞噬泡,后者是一种次级溶酶体,呈CMP酶阳性反应。睾丸间质细胞是分泌雄性激素的内分泌细胞,其光面内质网和线粒体在类固醇激素分泌中起重要作用,自体吞噬活动的结果是去除部分内质网和线粒体,可能在细胞水平上起着对雄性激素分泌的调节作用。     

莼菜(Brasenia schreberi)表皮腺毛细胞高尔基体中一种内含物的初步研究(简报)

在不经过任何特殊处理的常规生物样品中,高尔基体扁囊(Saccules)及囊泡(Vacuoles)中的内含物在电镜下常为低电子密度,而最近我们在莼菜(Brasenia schreberi)叶柄及叶片的表皮腺毛细胞中观察到带有高电子密度的高尔基体内含物。在扁囊中,这些内含物多呈波浪形(图版Ⅰ,图1)。这种特殊形态的高尔基体内含物以及这种未经任何特殊处理而显示出高尔基体中某些物质的现象是前人没有报道过的,本文就这种内含物的结构、性质以及其染色机制进行了初步探讨。     

Studies on the mechanisms of autophagy: maturation of the autophagic vacuole

Data presented in the accompanying paper suggests nascent autophagic vacuoles are formed from RER (Dunn, W. A. 1990. J. Cell Biol. 110:1923-1933). In the present report, the maturation of newly formed or nascent autophagic vacuoles into degradative vacuoles was examined using morphological and biochemical methods combined with immunological probes. Within 15 min of formation, autophagic vacuoles acquired acid hydrolases and lysosomal membrane proteins, thus becoming degradative vacuoles. A previously undescribed type of autophagic vacuole was also identified having characteristics of both nascent and degradative vacuoles, but was different from lysosomes. This intermediate compartment contained only small amounts of cathepsin L in comparison to lysosomes and was bound by a double membrane, typical of nascent vacuoles. However, unlike nascent vacuoles vet comparable to degradative vacuoles, these vacuoles were acidic and contained the lysosomal membrane protein, lgp120, at the outer limiting membrane. The results were consistent with the stepwise acquisition of lysosomal membrane proteins and hydrolases. The presence of mannose-6-phosphate receptor in autophagic vacuoles suggested a possible role of this receptor in the delivery of newly synthesized hydrolases from the Golgi apparatus. However, tunicamycin had no significant effect on the amount of mature acid hydrolases present in a preparation of autophagic vacuoles isolated from a metrizamide gradient. Combined, the results suggested nascent autophagic vacuoles mature into degradative vacuoles in a stepwise fashion: (a) acquisition of lysosomal membrane proteins by fusing with a vesicle deficient in hydrolytic enzymes (e.g., prelysosome); (b) vacuole acidification; and (c) acquisition of hydrolases by fusing with preexisting lysosomes or Golgi apparatus-derived vesicles.     

Integral Membrane Protein Sorting to Vacuoles in Plant Cells: Evidence for Two Pathways

Plant cells may contain two functionally distinct vacuolar compartments. Membranes of protein storage vacuoles (PSV) are marked by the presence of α-tonoplast intrinsic protein (TIP), whereas lytic vacuoles (LV) are marked by the presence of γ-TIP. Mechanisms for sorting integral membrane proteins to the different vacuoles have not been elucidated. Here we study a chimeric integral membrane reporter protein expressed in tobacco suspension culture protoplasts whose traffic was assessed biochemically by following acquisition of complex Asn-linked glycan modifications and proteolytic processing, and whose intracellular localization was determined with confocal immunofluorescence. We show that the transmembrane domain of the plant vacuolar sorting receptor BP-80 directs the reporter protein via the Golgi to the LV prevacuolar compartment, and attaching the cytoplasmic tail (CT) of γ-TIP did not alter this traffic. In contrast, the α-TIP CT prevented traffic of the reporter protein through the Golgi and caused it to be localized in organelles separate from ER and from Golgi and LV prevacuolar compartment markers. These organelles had a buoyant density consistent with vacuoles, and α-TIP protein colocalized in them with the α-TIP CT reporter protein when the two were expressed together in protoplasts. These results are consistent with two separate pathways to vacuoles for membrane proteins: a direct ER to PSV pathway, and a separate pathway via the Golgi to the LV.     

Fine Structure of Silica Deposition and the Origin of Shell Components in a Testate Amoeba Netzelia tuberculata1

ABSTRACT Netzelia tuberculata secretes a test composed of siliceous particles cemented together by organic plaques forming a single-layered spheroidal shell. The siliceous particles are produced within cytoplasmic vacuoles by three mechanisms: 1) synthesis de novo by deposition of the silica on a matrix; 2) deposition of silica on particles remaining in digestive vacuoles, including starch grains and undigested walls of yeast cells; and 3) secretion of silica as a hollow sphere at the periphery of vacuoles enclosed by the silicasecreting membrane. The silicalemma (silica-secreting membrane) originates as fibril-containing vesicles (GFV) secreted by the Golgi body. Fusion of these vesicles with membranes surrounding digestive vacuoles or with membranes surrounding specialized vacuoles containing a silica-binding matrix apparently converts the vacuole into a silica-depositing organelle. Small spherules of silica occur on the vacuolar side of the membrane surrounding the developing test granules, marking the presence of silicalemma activity. These colloidal spherules become aggregated into larger spherules that condense to form the siliceous surface of the developing test particle. Other Golgi vesicles, designated Golgi plaque vesicles (GPV), produce the organic plaques that are deposited among the siliceous particles at the periphery of the cell during new test construction during cell division. The fine structure of the GFV and GPV and their role in test wall deposition are discussed in relation to other silica-biomineralizing protozoa, including radiolaria.     

Ultrastructural localization of phosphatases in the testes of the domestic fowl: Acid phosphatase and thiamine pyrophosphatase

Summary ACPase and TPPase activity has been examined in the germinal epithelium of the testes in the domestic fowl. ACPase activity in spermatogonia and spermatocytes was confined to the Golgi complex. In spermatids ACPase activity was seen in the endoplasmic reticulum and nuclear envelope in the phase I and especially in the phase II (the elongating phase). This activity gradually decreased during the next phase III, and had disappeared in the final phase IV. The membrane body showed ACPase reaction in the small peripheral vacuoles and cisternal structures surrounding large central vacuoles. ACPase was also present in vesicles surrounding the developing tail. Late spermatids showed an abundance of autophagic vacuoles which had a complex array of ACPase positive delimiting membranes. In Sertoli cells ACPase activity was predominant in the lysosomes. TPPase activity was seen in the cisternae of the Golgi complex in spermatogonia and spermatocytes. In spermatids activity was present in the endoplasmic reticulum during the phase II, but it is lost in later stages. The smaller vacuoles and cisternal structures in the membrane body also showed reaction products. According to the present results it is thought likely that the smaller vacuoles and cisternal structures of the membrane body are of endoplasmic reticulum origin. The autophagic vacuoles in spermatids and the lysosomes of Sertoli cells are considered responsible for the degradation of residual bodies cast off by spermatids.     

Herpes simplex virus 1 envelopment follows two diverse pathways

Herpesvirus envelopment is assumed to follow an uneconomical pathway including primary envelopment at the inner nuclear membrane, de-envelopment at the outer nuclear membrane, and reenvelopment at the trans-Golgi network. In contrast to the hypothesis of de-envelopment by fusion of the primary envelope with the outer nuclear membrane, virions were demonstrated to be transported from the perinuclear space to rough endoplasmic reticulum (RER) cisternae. Here we show by high-resolution microscopy that herpes simplex virus 1 envelopment follows two diverse pathways. First, nuclear envelopment includes budding of capsids at the inner nuclear membrane into the perinuclear space whereby tegument and a thick electron dense envelope are acquired. The substance responsible for the dense envelope is speculated to enable intraluminal transportation of virions via RER into Golgi cisternae. Within Golgi cisternae, virions are packaged into transport vacuoles containing one or several virions. Second, for cytoplasmic envelopment, capsids gain direct access from the nucleus to the cytoplasm via impaired nuclear pores. Cytoplasmic capsids could bud at the outer nuclear membrane, at membranes of RER, Golgi cisternae, and large vacuoles, and at banana-shaped membranous entities that were found to continue into Golgi membranes. Envelopes originating by budding at the outer nuclear membrane and RER membrane also acquire a dense substance. Budding at Golgi stacks, designated wrapping, results in single virions within small vacuoles that contain electron-dense substances between envelope and vacuolar membranes.     

Studies on the mechanisms of autophagy: formation of the autophagic vacuole

Autophagic vacuoles form within 15 min of perfusing a liver with amino acid-depleted medium. These vacuoles are bound by a "smooth" double membrane and do not contain acid phosphatase activity. In an attempt to identify the membrane source of these vacuoles, I have used morphological techniques combined with immunological probes to localize specific membrane antigens to the limiting membranes of newly formed or nascent autophagic vacuoles. Antibodies to three integral membrane proteins of the plasma membrane (CE9, HA4, and epidermal growth factor receptor) and one of the Golgi apparatus (sialyltransferase) did not label these vacuoles. Internalized epidermal growth factor and its membrane receptor were not found in nascent autophagic vacuoles but were present in lysosome-like degradative autophagic vacuoles. All these results suggested that autophagic vacuoles were not formed from plasma membrane, Golgi apparatus, or endosome constituents. Antisera prepared against integral membrane proteins (14, 25, and 40 kD) of the RER was found to label the inner and outer limiting membranes of almost all nascent autophagic vacuoles. In addition, ribophorin II was identified at the limiting membranes of many nascent autophagic vacuoles. Finally, secretory proteins, rat serum albumin and alpha 2u- globulin, were localized to the lumen of the RER and to the intramembrane space between the inner and outer membranes of some of these vacuoles. The results were consistent with the formation of autophagic vacuoles from ribosome-free regions of the RER.     

An electron microscopical study of absorbing cells in the posterior caput epididymidis of rabbits

Summary The columnar cells in regions 3 and 4 of the ductus epididymidis in rabbits display ultrastructural features characteristic of absorbing cells. The stereocilia show basal anastomoses and often a fibrillar core continuous with a fibrillar web in the apical cytoplasm. Numerous invaginations of the slightly downy apical cell membrane and many thick-walled apical vesicles and vacuoles contain an opaque substance similar to that seen in the lumen. The vacuoles often contain small vesicles or bodies, probably formed from the vacuolar wall by budding. Numerous bodies or vacuoles with moderately dense contents are seen in the Golgi area and in the supranuclear and intranuclear cytoplasm in region 3. In region 4 they are denser and mainly seen above the nucleus. A high acid phosphatase activity was demonstrated in most dense and some light bodies. India ink introduced by way of the rete testis was taken up from the lumen into apical invaginations, vesicles and vacuoles and slowly transferred to denser bodies below the Golgi apparatus.These observations are interpreted as evidence for a resorption of substances from the lumen by a pinocytotic process, and for their storage and perhaps digestion in the dense bodies, which appear to have a lysosomal character. The Golgi apparatus is large with many vesicles of two types and empty cisternae but few typical Golgi vacuoles. The partly granular endoplasmic reticulum is very well developed and has opaque contents. Microtubules run from the terminal bar region into the Golgi area. Thick-walled vesicles occur throughout the cytoplasm, sometimes in continuity with the cell membrane. The basal parts of the cell borders often interdigitate.Supported by a grant from the Swedish State Medical Research Council.