Licht- und elektronenmikroskopische Untersuchungen an den Eihüllen der Elritze (Phoxinus phoxinus [L.];Teleostei,Cyprinidae)

Zusammenfassung Die Oocyten der ElritzePhoxinus phoxinus wurden licht- und elektronenmikroskopisch untersucht. Sie sind im Stadium I nur von der primären Oocytenmembran umgeben, die Mikrovilli zum Follikelepithel hin aussendet. Die Bildung der eigentlichen Eihülle, des Cortex radiatus, beginnt im frühen Stadium II. Der Cortex radiatus differenziert sich bald in den Cortex radiatus externus und den Cortex radiatus internus, wobei der Externus vor dem Internus angelegt wird. Die Differenzierung der Cortex-Schichten ist gegen Ende des Stadiums III abgeschlossen. Aussehen und Aufbau des Cortex radiatus externus der Elritze weichen stark von dem bisher bei anderen Cypriniden-Eizellen gefundenen Schema ab. DiePhoxinus-Eihüllen gleichen mehr denen von Salmoniden. Die Bildung der Rindenvakuolen erfolgt in einfacher Schicht überall gleichzeitig in den Eizellen unterhalb der primären Oocytenmembran. Sie breiten sich zentripetal aus. Die Rindenvakuolen entstehen beiPhoxinus phoxinus wahrscheinlich größtenteils durch Verschmelzung von Vesikeln.

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Light and electron microscopic studies of the envelopes in egg cells of the minnow (Phoxinus phoxinus [L.];Teleostei, Cyprinidae)

Summary The oocytes of the minnowPhoxinus phoxinus were examined by light and electron microscopy. In stage I they are only enveloped by the primary oocyte membrane which extends microvilli towards the follicle epithelium. The development of the actual egg envelope, the cortex radiatus, starts early in stage II. The cortex radiatus differentiates soon into the cortex radiatus externus and the cortex radiatus internus. In the course of this development the externus is formed earlier than the internus. The differentiation of the cortex layers is finished about the end of stage III. The exterior and the structur of the cortex radiatus externus of the minnow differs widely from the scheme found at other cyprinid oocytes. ThePhoxinus egg envelopes resemble more those of salmonids. The development of the cortical alveoli takes place simultaneously in the oocytes beyond the primary oocyte membrane. They expand centripetally. The cortical alveoli ofPhoxinus phoxinus probably derive for the most part from fusion of vesicles.

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Herrn Prof. Dr. Dr. h. c. W. E.Ankel zu seinem 80. Geburtstag gewidmet.     

Ultrastruttura della cellula apicale di Halopteris scoparia (L.) Sauvageau (Phaeophyceae,Sphacelariales)

Abstract

Ultrastructure of the apical cell of Halopteris scoparia (L.) Sauvageau (Phaeophyceae, Sphacelariales). - The ultrastructure of resting apical cells of Halopteris scoparia (L.) Sauvageau from material collected in December is described. The cytoplasm is higly vacuolated with lipids, poliphenolic substances and polisaccharides occurring inside the vacuoles (the classic « physodes »).

Two cell organelles are prominently active at this stage: conspicuosly hypertrophic dictyosomes and the budding endoplasmic reticulum. Both light and electron microscope observations show that the cell wall has an outer stratification and inner discontinuous thickenings, the constituent material of which is uniformerly dispersed.

The above observations point out that the apical cell of Halopteris scoparia at this stage of its life cycle is engaged in an elaboration of vacuolar and parietal substances which will be therefore readly available at the outset of the growing season.     

Three-dimensional analysis of the senescence program in rice (Oryza sativa L.) coleoptiles

The cytological sequence of senescence-related changes in coleoptiles of rice (Oryza sativa L. cv. Nippon-bare) was studied using fluorescence and electron microscopy. The coleoptiles reach full size 3 d after sowing, then rapidly senesce and wither completely by day 7. The interveinal region in cross-sections taken 1 mm from the tip of the coleoptile was selected for this analysis. Fluorescence microscopy using samples embedded in Technovit 7100 resin, electron microscopy and immunoelectron microscopy using DNA-specific antibodies were used to elucidate the sequence of senescence-related events. These occur in the following order: (i) degradation of the chloroplast DNA (cpDNA); (ii) condensation of the nucleus in conjunction with a decrease in the size of the dense-chromatin region, shrinkage of the chloroplast, degradation of ribulose-1, 5-bisphosphate carboxylase/oxygenase, dilation of the thylakoid membranes, increase in size and number of osmiophilic globules, condensation of the cytoplasm; (iii) disorganization of the nucleus, degeneration of the tonoplast; (iv) complete loss of the cytoplasmic components, distortion of the cell wall, invasion of microorganisms into the intercellular spaces and ultimately into the cell itself. The mitochondria maintain their ultrastructural integrity and a constant level of mitochondrial DNA throughout senescence. In young mesophyll cells, invagination of the tonoplast into the vacuole frequently occurs. This occasionally includes cytoplasmic material, which is digested in the vacuole as senescence proceeds. Immunoelectron microscopy suggests that cpDNA degradation involves rough digestion first, rather than rapid, direct decomposition of the DNA into nucleotides. The fragmented cpDNA is then dispersed throughout the chloroplast and cytoplasm. Received: 9 April 1998 / Accepted: 11 June 1998     

On the ultrastructure of the ovary of the liver fluke (Fasciola hepatica L.)

Summary The ovary of the liver fluke has been studied with light and electron microscopy. The organ consisted of germ cells and a layer of peripheral cells suggested to be nurse cells, and was surrounded by a capsule containing muscular tissue. The peripheral cells rested on a thick basement membrane and were irregular in outline. Their nuclei were of irregular shape, the mitochondria were dark with few cristae and the endoplasmic reticulum was tubular or vesicular and partly studded with ribosomes. The germ cells were rounded or polyhedral except in the outer part of the ovary where some of them showed irregular processes. The germ cells of the outer region (oogonia) were relatively small and in close contact with the cells suggested to be nurse cells. The inner germ cells (oocytes) were large and loosely packed. Their nuclei were irregular and contained round distinct nucleoli. The nuclear envelopes showed numerous pores. The endoplasmic reticulum was very sparse, but free ribosomes were abundant in the cytoplasm. This corresponded with a strong basophilia removable with RNase. In addition round basophilic bodies formed by densely packed ribosomes and membraneous material occurred in close spatial relation to mitochondria. The latter contained dense granules and few cristae. Groups of vesicles and membraneous lamellae were found in the cytoplasm, but they were considerably smaller than vertebrate Golgi complexes. Numerous dense spherical granules were found mainly in the periphery of the large germ cells. The granules were strongly osmiophilic except in the terminal part of the ovary. They were PAS-positive, but negative to Sudan dyes.Supported by a grant from Jordbrukets Forskningsråd, Stockholm.     

Kurze Mitteilung: Markieren von Kleinfischarten mit Acryl-Farben am Beispiel der Bachschmerle (Noemacbeilus barbatulus L.)

The suitability of acrylic colours for marking stone loach (Noemacheilus barbatulus L.) Acrylic colours were tested in the stone loach Noemacheilus barbatulus and were found to be useful for long term marking of small benthic fishes. No negative influences on condition or growth of the fishes were observed. The colours green and white produced best results in durability, still being visible in 90 % of the specimens after one year.     

Ultrastructural Studies on the Development of Oil Cells in Litsea pungens

The developmental process of oil cells in the shoot of Litsea pungens Hemsl. has been studied with transmission electron microscopy. According to the development of the three layers of cell wall, the developmental process could be divided into 4 stages. In stage 1, the cell wall consisted only of a primary (the outmost) cellulose layer, which might further be divided into two substages, the oil cell initial, and the vacuolizing oil cell. During this stage, there were some small electron translucent vesicles and dark osmiophilic droplets of variant sizes in the different-shaped plastids. It was observed that some dark and gray osmiophilic materials coalesced to vacuoles in the cytoplasm. In stage 2, a lamellated suberin layer accumulated inside the primary cellulose layer. In stage 3, a thicker and looser inner cellulose wall layer was formed gradually inside the suberin layer. Some dark osmiophilic droplets have been observed in this loose inner cellulose wall layer. The plasmodesmata were blocked up and became a special structure. Then, the big vacuole, which is the oil sac, was full of osmiophilic oil. In stage 4, the oil cell became matured and the cytoplasm disintegrated. The oil sac enveloped from plasmalemma was attached to the cupule, which was formed by the protuberance of the inner cellulose wall layer into the lumen. After the maturity of oil cell, the ground cytoplasm began to disintegrate and became electron opaque or exhibited in a disordered state, and the osmiophilic oil appeared light gray.     

木姜子油细胞发育的超微结构研究

利用超薄切片法和透射电镜研究了木姜子（Litsea pungens Hemsl.）油细胞的发育过程。油细胞3层细胞壁的发育可分为4个阶段,阶段1：油细胞仅有初生纤维素壁层,又可分为原始细胞和细胞 泡化两个时期。此阶段质体具透明小泡和黑色嗜锇物质,并与液泡融合。阶段2：木栓质化壁层的形成,片层状木栓质不断叠加在初生纤维素壁内侧,其细胞结构与前期相似,阶段3：内纤维素壁层的形成,较厚而松散的内纤维素壁层叠加在木栓质化壁层的内侧,在内纤维素壁层中可见黑色嗜锇物质,胞间连丝成为被阻塞的特化结构,此时大液泡被嗜锇油脂充满,成为油囊。阶段4：油细胞成熟及细胞质解体,杯形构造由内纤维素壁层向细胞腔内突起形成,油囊由液泡膜包被连接到杯形构造上,油呈浅灰色嗜锇状态,其细胞质和细胞器解体,变得电子不透明或呈杂乱状态。     

Ultrastructural study of oogenesis in Phoronopsis harmeri (Phoronida)

Temereva, E.N., Malakhov, V.V. and Yushin, V.V. 2011. Ultrastructural study of oogenesis in Phoronopsis harmeri (Phoronida). —Acta Zoologica (Stockholm) 92 : 241–250. The successive stages of oogenesis in Phoronopsis harmeri were examined by electron microscopy methods. During the oogenesis, each oocyte is encircled by vasoperitoneal (coelomic) cells forming a follicle. The previtellogenic oocytes are small cells which accumulate ribosomes for future synthesis; their cytoplasm contains characteristic clusters of mitochondria and osmiophilic particles resembling a germ plasm of other metazoans. The cytoplasm of the vitellogenic oocytes includes numerous mitochondria, cisternae of the rough endoplasmic reticulum, Golgi bodies and annulate lamellae. The synthesis of three types of inclusions was observed: strongly osmiophilic granules (lipid droplets) as a prevalent component, distinctly larger granules surrounded by membrane (proteinaceous yolk) and numerous large vesicles with pale flocculent content. No inclusions which could be unequivocally interpreted as the cortical granules were detected. The surface of the vitellogenic oocytes is covered by microvilli which increase in number and length during development. The oogenesis in Phoronida may be interpreted as follicular because of close association of oocytes with the vasoperitoneal tissue. However, well‐developed synthetic apparatus together with a strongly developed microvillous surface and absence of endocytosis indicate a clear case of autosynthetic vitellogenesis. Thus, in phoronids, there is a combination of simply developed follicle and autosynthesis that, apparently, is plesiomorphic character.     

Cytochemistry of pollen development in Campsis radicans (L.) Seem. (Bignoniaceae)

In this study, cytochemical staining methods were used to follow the cytochemical modifications of microspore cytoplasm and sporoderm in Campsis radicans (L.) Seem. from tetrad stage to mature pollen. Flower buds were collected at different stages of development, and the anthers were fixed and embedded in Araldite. To make cytochemical observations under light microscope, semithin sections were cut and stained with different dyes. Cytochemical methods provided the opportunity to localize the reserve material in the microspore and pollen cytoplasm, to distinguish the different layers of the sporoderm, and to determine its chemical structure at different developmental stages. Microspore cytoplasm contains variable amounts of proteins, lipids, and insoluble carbohydrates at different stages of microsporogenesis. Sporoderm formation starts at tetrad stage by the formation of primexine and is completed at vacuolated microspore stage by the addition of sporopollenin from tapetum. During the vacuolization and enlargement of the microspores, the structure and the chemical composition of the exine are modified. The endexine becomes chemically different from the ectexine. The ectexine is composed of sporopollenin and a small amount of protein, whereas the endexine is composed of sporopollenin, proteins, and traces of polysaccharides.     

Ultrastructure of microsporogenesis and microgametogenesis in Campsis radicans (L.) Seem. (Bignoniaceae)

In the present study, microsporogenesis, microgametogenesis and pollen wall ontogeny in Campsis radicans (L.) Seem. were studied from sporogenous cell stage to mature pollen using transmission electron microscopy. To observe the ultrastructural changes that occur in sporogenous cells, microspores and pollen through progressive developmental stages, anthers at different stages of development were fixed and embedded in Araldite. Microspore and pollen development in C. radicans follows the basic scheme in angiosperms. Microsporocytes secrete callose wall before meiotic division. Meiocytes undergo meiosis and simultaneous cytokinesis which result in the formation of tetrads mostly with a tetrahedral arrangement. After the development of free and vacuolated microspores, respectively, first mitotic division occurs and two-celled pollen grain is produced. Pollen grains are shed from the anther at two-celled stage. Pollen wall formation in C. radicans starts at tetrad stage by the formation of exine template called primexine. By the accumulation of electron dense material, produced by microspore, in the special places of the primexine, first of all protectum then columellae of exine elements are formed on the reticulate-patterned plasma membrane. After free microspore stage, exine development is completed by the addition of sporopollenin from tapetum. Formation of intine layer of pollen wall starts at the late vacuolated stage of pollen development and continue through the bicellular pollen stage.     

Cytology of oocytes in ground squirrels (Citellus citellus L.)

Oocytes of primordial, primary, growing, and Graaf follicles of the ovaries of 96 ground squirrels (Citellus citellus L.) were studied during the four seasons of the year. Multilamellar bodies in the oocytes were observed by electron microscopy. The bodies underwent changes during the follicle growth. The vesicles included in the multilamellar bodies were filled with an amorphous substance, while in Graaf follicles trapezoidal, rhomboidal, and hexagonal inclusions were found. The primordial follicle of the oocyte had no Balbiani body. In the hibernating ground squirrel the functions of the Balbiani body were probably performed by the multilamellar bodies, which were considered to be analogous to the Balbiani body.     

Seasonal changes of the ovarian atretic follicles of the ground squirrel (Citellus citellus L.)

The ovaries of 84 ground squirrels (C. Citellus L.) were studied during the four seasons of the year. The ovarian atretic follicles were examined by histological methods and by electron microscopy. The histoenzyme activities of NAD.H2-tetrazolium reductase, glucose-6-phosphate dehydrogenase, and 3 beta-hydroxy-delta 5-steroid dehydrogenase were photometrically demonstrated. The steroid-producing atretic follicles were mainly described as they reached their highest enzyme activity during the lactation period in April. The atresia of the primordial and primary follicles was manifested by disappearance of the oocyte and preservation of the granulose cells surrounded by basal lamina. Atresia of follicles with two oocytes was a typical process for the ground squirrel. Later on the oocytes and the granulose cells around it disappeared. The remaining part of the follicle continued its development and reached maturity. Atresia was observed mainly in March, April, and May.     

A network system for vitellogenin synthesis in the mussel Mytilus galloprovincialis (L.)

The aim of this study is to assess, by RT‐PCR, in situ hybridization, electron microscopy, and immunohistochemistry, the site/s of vitellogenin (VTG) synthesis in the mussel Mytilus galloprovincialis. Our investigations demonstrate that, among the analyzed tissues, the synthesis of VTG occurs only in the female gonad, that is, within the oocyte and follicle and connective cells. Such a synthesis is just evident in early vitellogenic oocytes, whose cytoplasm is characterized by numerous RER cisternae and an extended Golgi complex surrounded by nascent yolk platelets. The synthesis of VTG goes on in vitellogenic oocytes assuming a pear form, and progressively reduces once the oocyte shows the pear or polygonal form, typical of those oocytes that have concluded the growth. The expression of VTG occurs also within follicle (auxiliary) and connective cells. In particular, it is noteworthy that follicle cells are characterized by numerous RER cisternae and an active Golgi complex surrounded by numerous vesicles and vacuoles containing electron dense material. The same material is also present along their plasma membrane, within the intercellular space between oocyte and follicle cells, and finally within invaginations of the oocyte surface, thus suggesting a VTG transfer to the oocyte via endocytosis. Differently, no VTG synthesis was observed within digestive gland. All together the findings here reported strongly suggest that in M. galloprovincialis, inside the gonad, the VTG synthesis occurs in the oocyte (autosynthesis) and in the follicle and adipogranular cells (heterosynthesis). J. Cell. Physiol. 228: 547–555, 2013. © 2012 Wiley Periodicals, Inc.     

Electron Microscopic Observation on the Infected Cells During Pea (Pisum sativum L.) Nodule Senescence

Ultrastructural changes of the infected cells have been observed by transmission electron microscopy during pea root nodule senescence. The infected cells and bacteroids of pea nodules ultimately senesce, their senescence has certain laws and features. Firstly, peribacteroid membrane were loosened, leaving a large electron-empty space with fibrillar and vesicular material. Then bacter0id cytoplasm lost features and aggregated into some clustered electron- dense material. At next stage bacteroids were structurally emtpy and appeared like “ghost” cells. Companying bacteroid senescence, host cytoplasm changed from dark to light in electron density and cell organelles gradually decreased. After the host cell tonoplasts and plasmalemma broke down, the infected cells showed a chaotic state of bacteroids and host cell debrises. Finally, infected cells disintegrated completely. Sometimes some young bacteria were seen in the intercellular spaces surrounded by degenerating cells, in the degenerating cytoplasm. A few infection threads were also found among the disintegrated bacteroids, even some of them were releasing the bacteria into the degenerating host cytoplasm.     

Ultrastructure analysis of cadmium-tolerant and -sensitive cell lines of cucumber (<Emphasis Type="Italic">Cucumis sativus</Emphasis> L.)

Previously, a stable cell suspension culture of cucumber tolerant to cadmium (Cd) was established (Gzyl and Gwóźdź, Plant Cell Tissue Organ Cult 80:59–67, 2005). In this study, ultrastructures of Cd-tolerant and -sensitive cells were analyzed by transmission electron microscopy (TEM). Ultrastructural differences between cell lines exposed to 100 μM CdCl₂ were observed both at cellular and organelle levels. Tolerant cells exposed to Cd exhibited well-preserved cellular structures in comparison with sensitive cells. Increased numbers of osmiophilic globules in the cytoplasm and nucleolus-associated bodies as well as electron dense material in vacuoles were observed in cadmium tolerant cells. In contrast, ultrastructure of sensitive cells following exposure to Cd exhibited distinct disturbances including vacuolation, disintegration of cytoplasm, and structural changes in both mitochondria and endoplasmic reticulum. TEM observations confirmed the adaptation of tolerant cells to Cd.     

Physiological compartmentation in gonadal tissue of the common carp (Cyprinus carpio L.)

Summary Physiological compartmentation in carp (Cyprinus carpio L.) gonads was investigated after intracardial injection of horseradish peroxidase (HRP) and two mouse anti-carp-sperm monoclonal antibodies.Immunohistochemistry revealed that a physiological barrier exists in carp testis for HRP and mouse IgG monoclonal antibody around the central lumina of the tubules in which the spermatozoa are located, but not around the cysts containing the precursor germ cells. The results with HRP were confirmed by electron microscopy. Mouse IgM monoclonal antibody did not penetrate the spermatogenic cysts. Probably because of its large size, it was almost exclusively located inside blood capillaries and only sparsely in the interstitial tissue.In the ovary, HRP was regularly distributed in the gonadal tissue, whereas the IgG antibody was predominantly localised on oogonia and early prophase oocytes. The results indicate that in contrast with the testis, no barrier around germ cells exists in the carp ovary.     

The Ultrastructure and Analytical Microscopy of Silicon Deposits in the Roots of Saccharum officinarum (L.)

Silicon accumulation in the endodermis of the ‘set’and ‘shoot’ roots of Saccharum officinarum (L.)were investigated by scanning electron microscopy and electron-probemicroanalysis. Silicon microassay was also carried out by meansof the Corinth analytical microscope (CORA). Aggregates arelargely associated with the inner tangential wall (ITW) of theendodermis and their formation is basically similar to thoseseen in Sorghum bicolor (L.) Moench. In contrast to Sorghumthe earliest deposits in Saccharum appear in wall strata wellwithin the cell wall cytoplasm interface. An additional layerof silicon was also located along the endodermal pericycle boundaryextending some distance along the middle lamella of the radialwalls. The results are discussed in relation to those of previous studiesof silicon accumulation in endodermal cells and to possiblefactors affecting such accumulations.     

DIFFERENTIATION OF SERTOLI CELLS AND POST--REPRODUCTIVE EPITHELIAL CELLS IN THE HERMAPHRODITE GLAND OF ARION ATER(L.) (MOLLUSCA, PULMONATA)

Differentiation of Sertoli cells and post-reproductive epithelialcells during development of the hermaphrodite gland has beendescribed in Arion ater (L.) at the fine structure level. Twodifferent stages of Sertoli cells, active and atrophic, arerecognized. The cytoplasm during the active stage shows highmetabolic activity by many lysosome-like inclusions and otherorganelles. The possible role of steroidogenesis of these cellsis discussed in relation to their fine structure. The post-reproductive epithelial cells appear in the gland approximatelyafter the sheddingof both spermatozoa and oocytes. These cellsmay fill the lumen of the gland and appear syncytial. ^*Present address: Department of Biology, School of Sciences,Mashad University, Mashad, Iran (Received 12 January 1979;     

茶叶叶绿体的嗜锇颗粒含量和适制茶类的关系

应用电子显微镜技术,从细胞亚显微水平研究了81个茶叶品种(或品系)的叶绿体内嗜锇颗粒的分布情况及其适制茶类的关系。结果表明,适制乌龙茶的茶树品种嗜锇颗粒含量都比较多,而有特殊香气的凌云白毛茶嗜锇颗粒含量高达100—46(平均值58),认为嗜锇颗粒含量与成茶香气有关,研究不同茶树品种的嗜锇颗粒含量可为茶树品种的成茶适制性和育成高香型品种的亲本选择提供参考依据。