魏氏拟尾柱虫休眠包囊及其细胞器超微结构的观察

为研究纤毛虫休眠状态下细胞的分化及其胞器的特征,本文以透射电镜术显示,魏氏拟尾柱虫（Ｐａｒａｕｒｏｓｔｙｌａｗｅｉｓｓｅｉ）休眠包囊中,颗粒层壁内有小泡,表膜位置偶见小泡样结构,大部分线粒体以多个相互聚集在一起,自噬泡将线粒体等胞器包裹在内经历消化过程,细胞内膜系统十分发达。作者推测,颗粒层及表厝小泡可能是休眠细胞经由表膜进行物质交换的结构,自噬泡消化现象可能是细胞中物质和能量来源的主要途径。     

草丛土毛虫皮层纤毛器的微管胞器研究

本文应用FLUTAX直接荧光标记和抗α-微管蛋白抗体免疫荧光标记．显示了土壤纤毛虫草丛土毛虫（Territricha stramenticola）的皮层纤毛器微管胞器．其中纤毛器基部微管按口围带、波动膜、额腹横棘毛、左右缘棘毛、背触毛等纤毛器图式分布和定位,口围带和波动膜基部含小膜微管托架、小膜附属微管和波动膜微管骨架网;额腹横棘毛基部含前纵微管束、后纵微管束和横微管束：左、右缘棘毛基部含前纵微管束、后纵微管束、横微管束及后微管芽;背触毛基部含前纵微管束、后纵微管柬。横棘毛基部含有较发达的横微管束,缘棘毛基部含后微管芽及其横微管束的定位可能具有本种纤毛虫细胞的特异性。纤毛器微管胞器在细胞表膜下分化形成的基部微管及其微管层使细胞的运动纤毛器与强固的微管骨架结构网相联系．其微管胞器的建构可能是细胞对土壤生存环境的一种适应．是细胞运动胞器的功能活动与环境相互作用的结果。形态发生中,老口围带微管是逐步进行更新的：老棘毛微管胞器对新结构的发生和形成具有定位和物质贡献的作用．并且老结构在新结构分化和成熟期间也经历了行使相应的生理功能及逐渐退化和失去功能的过程．     

阔口尖毛虫皮层纤毛器微管在不同生理条件下的分化

应用激光扫描共聚焦显微术,显示腹毛类纤毛虫阔口尖毛虫(Oxytricha platystoma)无性生殖过程中,新的口围带、波动膜、额腹横棘毛、左右缘棘毛微管先后分化,老纤毛器微管去分化,细胞分裂产生各含一套纤毛器微管的前、后两仔虫;生理改组过程中,口围带、波动膜、额腹横棘毛、左右缘棘毛微管发生去分化和再分化,细胞皮层微管胞器更新形成含一套纤毛器微管的新细胞。结果表明阔口尖毛虫在无性生殖和生理改组这两种不同的生理条件下,其纤毛器微管结构的形成或更新可能具有相同的细胞调控机制,形态发生中老纤毛器结构可能对新结构的发生和发育具有诱导定位和物质贡献的作用。     

原生动物的细胞器（二）

(四)纤毛虫的细胞小器和胞器复合 1.纤毛、动胞器(kinetid)和动胞器列(kinety)纤毛的超微结构与鞭毛的基本相同,其基部的一段名动体,是由9组三联体微管围成的短圆柱状体。动体可成双存在,也可成单或多个聚集存在。动体和与它相联的纤维加上围绕这一动体单元的表膜结构合称为动胞器。许多动胞器前后相联成行,叫做动胞器列。与动体相联的各种纤维及微管可能具有传导或支持作用。另有可发射刺丝的刺丝泡。高等纤毛虫有的纤毛发生合并形成棘毛,有的棘毛含数十根纤毛,形如毛笔。棘毛又称复动胞器(polykinetid)。 2.口旁膜(paroral membrane)和小膜(membranelle)属于口纤毛器的一部分。口     

新伪尾柱虫腹皮层纤毛器微管胞器的形态和形态发生

应用荧光紫杉醇直接荧光标记法显示,腹毛目纤毛虫新伪尾柱虫(Pseudourostyla nova)腹皮层纤毛器微管胞器由口围带、波动膜、额腹横棘毛和左右缘棘毛等纤毛器微管及纤毛器基部附属微管组成.口围带基部含小膜托架及与托架相联系的肋壁微管,其中领部小膜托架间由"Λ"形微管相联接;额腹横棘毛基部含前纵微管束、后纵微管束、横微管束和周围微管束,其微管在不同棘毛基部的发达程度不一;缘棘毛基部含前纵微管束、后纵微管束.同时,对新伪尾柱虫纤毛器微管胞器的形态发生和生理改组过程进行了详细的追踪研究,并对细胞皮层的额腹棘毛定位及组成特征进行了补充报道.此外,发现形态发生末期新纤毛器微管形成时,残存部分老额棘毛、横棘毛和缘棘毛,此后老结构逐渐被吸收.结果表明,新伪尾柱虫的纤毛器基部微管具有其种的特异性,新纤毛器微管分化过程中老结构可能具有定位和物质贡献作用.     

腹毛目纤毛虫大尾柱虫腹皮层纤毛器基部微管的荧光标记

应用荧光紫杉醇直接荧光标记,显示腹毛目纤毛虫大尾柱虫Urostyla grandis腹皮层纤毛器微管胞器由口围带、波动膜、额腹横棘毛和左、右缘棘毛等纤毛器微管、纤毛器基部附属微管等组成.其中,口围带小膜托架及其相联系的肋壁微管和波动膜基体托架,额棘毛基部前纵微管束、后纵微管束及横棘毛基部前纵微管束,中腹棘毛及左、右缘棘毛基部前纵微管束、后纵微管束和横微管束,是该纤毛虫皮层纤毛器基部的主要附属微管.据结果推测,尽管腹毛目纤毛虫的纤毛器基部微管具有相同的结构成分,但其结构的组成、分化特征、定位和定向、发达程度等均有差异.所得结果为进一步说明纤毛虫细胞皮层纤毛器的形态及其微管建构的多样性提供了新的证据资料.     

原生动物贻贝棘尾虫微管胞器的荧光标记与显示

采用FLUTAX直接荧光标记和抗α微管蛋白抗体的间接免疫荧光标记显示,原生动物贻贝棘尾虫(Stylonychia mytilus)细胞微管胞器由口围带、波动膜、额腹横棘毛、左右缘棘毛、背纤毛等纤毛器微管骨架、纤毛器基部附属微管和其他皮层微管骨架组成。纤毛器微管骨架和基部附属微管按皮层纤毛模式定位;皮层左、右侧微管带和领肋壁微管等其他皮层微管构成细胞特定位置的皮层微管骨架,并可能为具有背腹分化的腹毛目纤毛虫所特有,对维持细胞背腹面的形态、支持附近纤毛器(如左、右缘棘毛)的运动起作用。本文较完整地阐述了其细胞骨架的三维构形,对于深入了解纤毛虫细胞微管骨架的结构和分布特征,进一步揭示微管类胞器的功能是有意义的。     

华美游仆虫细胞微管胞器的直接荧光和免疫荧光标记

应用直接荧光和免疫荧光标记显示,腹毛目纤毛虫华美游仆虫(Euplotes elegans)细胞微管胞器由口围带、波动膜、额腹横棘毛、缘棘毛、尾棘毛、背触毛等纤毛器微管以及纤毛器基部附属微管和非纤毛区皮层微管骨架组成.其中,口围带基部含有小膜托架、小膜附属微管,波动膜基部含有波动膜托架,额腹横棘毛基部含有前纵微管束、后纵微管束、横微管束或放射微管柬,左缘棘毛和尾棘毛基部微管束分化不明显,背纤毛基部含有攻瑰花状的基体周围骨架,这些微管结构与细胞背腹面皮层纵微管与横微管网一起组织成该类纤毛虫的主要皮层细胞骨架.结果表明,游仆虫皮层细胞骨架是以微管为主要成分构建而成的,并且其棘毛基部微管的组成具有与其他类纤毛虫不同的特征;游仆虫间期细胞及形态发生时期纤毛基体或纤毛原基中存在中心蛋白,其可能与纤毛基体结构的维持及基体发生过程中微管的组装有关.     

冠突伪尾柱虫的腹皮层纤毛器微管胞器及其形态发生

应用荧光紫杉醇直接荧光标记和抗α-微管蛋白抗体免疫荧光标记方法,显示冠突伪尾柱虫腹皮层纤毛器微管胞器由口围带、波动膜、额腹横棘毛和左右缘棘毛等纤毛器微管、纤毛器基部附属微管等组成。口围带基部含小膜托架及与托架相联系的肋壁微管,其中领部小膜托架间由"∧"形微管相联接;额腹横棘毛基部含前纵微管束、后纵微管束、横微管束和周围微管束,其微管在不同棘毛基部的发达程度不一,其中两列中腹棘毛基部微管紧密联系成一条粗绳索样结构,且左、右中腹棘毛基部的横微管束定向相反;左、右缘棘毛基部含前纵微管束、后纵微管束和横微管束,其中横微管束不发达。与目前已知的腹毛目纤毛虫例如贻贝棘尾虫、魏氏拟尾柱虫的纤毛器基部微管相比较,冠突伪尾柱虫腹皮层纤毛器基部微管除具有腹毛目纤毛虫纤毛器基部微管的基本特征外,也具有一些特殊的组成模式。皮层纤毛器微管形态发生中,前仔虫口围带并非全部是由老口围带更新而来的,其老口围带只有翻领部发生更新,且翻领部与领部接续处有一小段老的翻领部小膜保留,领部的小膜保留,结果其领部小膜、接续处保留的小膜与更新的翻领部小膜三部分共同组成前仔虫的新口围带。在后仔虫口原基发生的位置,其邻近的老横棘毛没有变化,此时老的横棘毛或许能起到"参照点"或定位作用;各类纤毛器发生、分化过程中,处于非原基区的老额棘毛、横棘毛及左右缘棘毛在较长时间内均未见明显的变化。它们可能是在新结构形成时仍然起到运动作用继而逐渐失去功能而退化瓦解的。     

魏氏拟尾柱虫腹皮层纤毛器微管胞器的形态及形态发生

应用荧光紫杉醇直接荧光标记和抗α-微管蛋白抗体免疫荧光标记显示,魏氏拟尾柱虫(Paraurostyla weissei)腹面皮层纤毛器微管胞器由口围带、波动膜、额腹横棘毛和左右缘棘毛等纤毛器微管、纤毛器基部附属微管等组成。其中口围带基部微管包括小膜托架、小膜附属微管;额腹横棘毛和左右缘棘毛基部附属微管包括前纵微管束、后纵微管束和横微管束,它们由各自的纤毛器基部向皮层细胞质不同方向发射,形成腹皮层表面下微管网。结果表明,魏氏拟尾柱虫的纤毛器骨架、纤毛器附属结构也是一类以微管蛋白为基本成分的微管胞器,其中缘棘毛基部附属微管具有不同于其他纤毛虫(例如棘尾虫)中所观察到的同种微管胞器的建构特征。形态发生中,前仔虫口围带在老结构位置形成,其结构建成与部分老口围带的更新有关;老缘棘毛的结构物质对新的左、右缘棘毛的发生可能具有定位作用及物质贡献,但此后新的左、右缘棘毛列分别在老缘棘毛的右侧形成,而并非是在老缘棘毛位置分化的。在有些细胞中,新的左缘棘毛左侧另有一列棘毛,这可能是形态发生中老的左缘棘毛退化不完全产生的。     

The ultrastructure of the extrusomes in <Emphasis Type="Italic">Pseudourostyla cristata</Emphasis>, a hypotrichous ciliated protozoan

By using scanning and transmission electron microscopy, the present study demonstrates a great number of trichocyst-like extrusomes distributed in the cortical cytoplasm of the protozoan Pseudourostyla cristata, a hypotrichous ciliate. Of these, the mature organelles are rod-shaped with a cap consisting of tubular structures, a tip located at the apex of the cap, a body consisting of strateform structures of uneven electron density and an elongated shaft located along the longitudinal central axis of the body. The electron microscopic observations suggest that the extrusive organelles in P. cristata might undergo a morphogenetic process including the following sequential events: the occurrence of the vesicles in the cytoplasm, the condensation of the fibrous substances within the vesicles, the appearance of the electron-dense shaft, and the formation of the cap. In contrast with a large quantity of extrusomes in trophozoit P. cristata, there are no such extrusive organelles in the encysted cells of the ciliate. The phenomena that P. cristata ciliates can readily enter physiological reorganization or encysting phases and discharge a great number of their extrusomes when prepared for SEM and TEM observation suggest that the extrusive process of the extrusomes in P. cristata might have an important influence on the life activity of the ciliate and could be one of the causes leading to the physiological reorganization and the encysting of the ciliate. These reactions of P. cristata might be a protective or defensive response to the environmental changes.     

Structure,function, and formation of extrusive organelles — microtoxicysts in the rhizopodPenardia cometa

Summary A study of the structure, function, and development of extrusive organelles (microtoxicysts) in the unusual bacteriovorous rhizopodPenardia cometa is performed. Microtoxicysts are located in the cortical cytoplasm of the cell body and in special thickenings on reticulopodia. Similar types of extrusomes have been observed in some cercomonads. The microtoxicysts are organized as membrane-bound vesicles of a complex form. An oviform-conical axial element lies inside each vesicle and is directed with its narrower end towards the plasma membrane. An internal cylindrical tube occupies the central part of the axial element; it is turned out as the organelle is shot out. The extrusomes ofP. cometa originate from and develop in derivates of the endoplasmic reticulum, the initial diameter of proextrusome vesicles is twice the diameter of the mature organelles. At late stages of maturation the microtoxicysts adopt their characteristic form and orientation. The mode of construction, ejection and development is compared with that in some other carnivorous and bacterivorous protists.     

The structure of extrusive organelles in alveolate and other heterotrophic flagellates

The structure of ejective organelles (extrusomes) in 12 species of heterotrophic flagellates belonging to 8 taxonomic groups is considered. Trichocysts of various structures have been found in colpodellids, Spumella and Metromonas. Kinetocysts of amoeboid flagellates, thaumatomonads, contain a cylindrical element. These kinetocysts are attached to bacteria after discharge. When being discharged, trichocysts of colpodellids produce filaments which have transversal striation. Discobolocysts have been found in excavate flagellate Reclinomonas, and ejectisomes--in Goniomonas. Toxicysts have been marked in carnivorous alveolate flagellate Colponema. The most of studied extrusomes lie inside the cytoplasm, while exstrusomes in chrysomonad Spumella are also found inside the nucleus. Trichocysts of colpodellids and Metromonas as well as ejectisomes of Goniomonas are located near the branches of Golgi apparatus. The comparison of the data obtained confirms the hypothesis about the correlation of taxonomic position of flagellates and the structure of their extrusomes that allows in some cases using these features as phylogenetic markers.     

Ultrastructure,biogenesis, and functions of extrusive organelles in selected non-ciliate protists

Summary The ultrastructural features, biogenesis and functions of several selected protist extrusive organelles are discussed. Most of the review focuses on some common extrusive organelles that were not considered by Hausmann and several types which have been described since that review of 16 years ago. For convenience, extrusomes are categorized as projectile or mucocyst extrusomes. The projectile extrusomes are further subdivided into non-penetrating and cell penetrating extrusomes. This review is restricted to projectile extrusomes such as ejectisomes, the microsporidian invasion apparatus, and the gun cell of oomycetes. Mucocysts include the apicomplexan rhoptries, the K₂ bodies of oomycetes, and the spermatial vesicles and adhesive vesicles of red algae. The possible phylogenetic importance of some extrusive organelles is briefly considered.     

Fine structural abnormalities in the developing mouse embryo

Initial changes in the fine morphology of apparently normal mouse zygotes and embryos were studied in serial sections of mouse oviducts that had been fixed in situ. These changes included extra sperm in the perivitelline space, nuclear budding, the presence of large nucleoli, perinuclear vesicles, the concentration of cytoplasmic organelles, and the extrusion of cytoplasmic ground substance. Initial changes in the nucleus and cytoplasm were undetectable when the zygotes and embryos were examined with the light microscope. It was concluded that serious abnormalities in zygotes and embryos, which may not be identified at the light microscope level, may be detected if they are examined in the electron microscope. Therefore, zygotes and embryos should be critically evaluated before being rated as normal.     

阔口尖毛虫形成包囊期间细胞超微结构的观察

阔口尖毛虫形成囊期间,细胞质内出现条带状或管产产的内质网和由不同大小的囊泡组成的包囊壁前体。并且,前体的产生与内质网有关;细胞质内发生自噬泡消化现象,这是细胞将原有结构和能量进行贮存,利用的一种重要形式;大核向细胞质突出形成阿米巴形结构,这与大核向细胞质排出部分核物质有关。     

Cytopathology of the soybean looper,Pseudoplusia includens,infected with the Pseudoplusia includens icosahedral virus

Ultrastructural responses of soybean looper cells of various tissues infected with Pseudoplusia includens icosahedral virus (PIIV), a newly characterized RNA virus [Y. C. Chao, H. A. Scott, and S. Y. Young (1983)J. Gen. Virol.64, 1835–1838], were studied in situ. Most cells of fat body and epidermis consistently contained virus particles and associated cytopathic structures. Virus particles, corresponding to those of purified PIIV in morphology and size, always occurred in the cytoplasm either in membrane-bound virogenic stroma and/or freely in the ground cytoplasm. Virogenic stroma, which appeared to be distinct from those induced by other insect viruses, consisted of electron-dense matrix material, in which virus particles were embedded, and membranous vesicles, 70 or 80 nm in diameter, containing nucleic acid-like fibrils. Virus particles in virogenic stroma occurred as hexagonally arranged crystalline arrays made up primarily of homogeneously dense particles, while those in the ground cytoplasm were dispersed randomly and had an electron-lucent central core. Extremely large numbers of virus particles were also located in noncellular cuticle layers of the integument.     

A Comparative Electron Microscopic Study of the Morphology of Toxoplasma gondii by Freeze-Etch Replication and Thin Sectioning Technic

SYNOPSIS. Freeze-etch preparations of Toxoplasma gondii reveal details of structure and organelles in 3-dimensional relationships. The subpellicular microtubules and their relationship to the polar ring, the tripartite pellicle, the pellicle constituents, and the spatial relationship of the rhoptries to the conoid and conoid canal are clearly demarcated.     

Cytochemical Nature and Fine Structure of the Gregarine Zeylanocystis burti Dissanaike, with Special Reference to Microfilaments, Microtubules and Movement

SYNOPSIS. The mature trophozoite of the acephaline gregarine Zeylanocystis burti Dissanaike, parasitic in the seminal vesicles of the Sri Lankan earthworm Pheretima peguana Rosa, was studied by cytochemical methods and by electron microscopy. Some observations were also made on gametocysts and oocysts. The trophozoite has a peculiar saucer shape, unlike other monocystid gregarines, and has marginal papillae with cytoplasmic hairs. Its fine structure conforms broadly to that of other gregarines, but differs with respect to its fibrillar organization and in some details of cytoplasmic organelle structure. The pellicle is composed of 2 parallel unit membranes elevated into a number of stumpy epicytary folds, more or less evenly distributed on both surfaces of the gregarine. Some of these are associated with adjacent accessory cells and may have a nutritive role. Bundles of fine microfilaments (5–6 nm) were detected both in the ectoplasm and deep in the endoplasm; these are possibly the main contractile elements (“myonemes”) involved in movement. Microtubules are larger (22–24 nm) and are found predominantly in papillae and cytoplasmic hairs, but extend also in small bundles beneath the pellicle—they appear to be more skeletal in nature. The significance of these findings is discussed in the light of recent work on the roles of microfilaments and microtubules in nonmuscle cells. Mitochondria are located superficially and have a complex organization. The endoplasmic reticulum is poorly developed, but ribosomes are abundant. Golgi lamellae-like membranes and vesicles akin to lysosomes were observed. Typical paraglycogen granules were found together with blobs of lipid and glycogen. The nucleus had a wrinkled envelope, a homogeneous matrix, and a spherical nucleolus. A variety of staining reactions and cytochemical tests were carried out. The distribution of lipids, polysaccharides, nucleic acids, calcium, and melanin were studied. Succinate dehydrogenase was detected in mitochondria, thiamine pyrophosphatase in Golgi bodies, and acid phosphatase in lysosomes. Golgi structures were found to be chemically very complex. Gametocysts and oocysts were associated with extraneous cells which probably contribute to the formation of their walls. The gametocyst wall is thin and consists of 2 membranes of the unit type. The oocyst wall is thicker and composed of 2 chemically different layers. Telolysosomes were seen in the disorganized residual cytoplasm within gametocysts.     

The formation of the pronuclei and their associated perinuclear cytoplasm; the determination of the phases of the first cleavage cycles in Crepidula fornicata (Mollusca,Gastropoda)

Summary

The behaviour of the male and the female pronuclei in Crepidula fornicata is studied, beginning at the formation of the second polar body. Shortly after the extrusion of the second polar body the female pronucleus is formed, and then the male pronucleus enters the yolk-free cytoplasm near the animal pole. Both pronuclei are enveloped by a typical nuclear membrane, and increase in size until the prophase; a zygote nucleus is not formed (“Ascaris type” of fertilization). In the meantime, the chromatin of both pronuclei is arranged in a meshwork in the centre of the pronuclei.

Shortly after the formation of the second polar body a special cytoplasm, the “perinuclear cytoplasm”, is formed in the vicinity of each of the pronuclei. During the early stages of the first cleavage cycle this cytoplasm is composed of numerous Golgi complexes, small dense Golgi vesicles, smooth endoplasmic reticulum vesicles, mitochondria and rosettes of glycogen-like granules. At later stages, when the pronuclei have met and their plasms coalesced, the number of Golgi elements decreases; at the same time, the small dense Golgi vesicles increase in number and aggregate in clusters.

The phases of the first three cleavage cycles are determined by cytophotometry. The nuclear DNA of the male pronucleus and that in the nuclei of the blastomeres of the 2- and the 4-cell stage is reduplicated between 7 and 33% of the normalized cleavage cycles; the G₂-phase is between 33 and 57%, while the mitotic phase occupies the last part of each cleavage cycle and the first 7% of the next cleavage cycle. There is no G j-phase. Since the female pronucleus lies just beneath the polar bodies, its DNA content could not be measured separately.