Synergistic effect of insulin and follicle-stimulating hormone on biochemical and morphological differentiation of porcine granulosa cells in vitro

Insulin and follicle-stimulating hormone (FSH) have been shown to facilitate granulosa cell differentiation in vitro. To gain insight into this process, we evaluated the effects of these hormones, alone and in combination, upon the biochemical parameters of luteinizing hormone/human chorionic gonadotropin (LH/hCG) receptor induction and progesterone secretion concomitantly with morphometric analysis of granulosa cell ultrastructure and LH/hCG receptor distribution by quantitative autoradiography under light microscopy. Granulosa cells isolated from small antral follicles (controls) cultured in the absence of exogenous hormones exhibited few microvilli and gap junctions; the mitochondria, endoplasmic reticulum, and Golgi complex were all poorly developed. Progesterone secretion was negligible and the cells bound little [125I]iodo-hCG. Insulin treatment increased gap junction formation, and the extent of smooth and rough endoplasmic reticulum and Golgi complex development (all p less than 0.05) but did not affect mitochondrial ultrastructure or volume. Insulin treatment modestly but significantly increased [125I]iodo-hCG binding and progesterone secretion relative to controls (p less than 0.001). FSH treatment had a similar effect to insulin on cell ultrastructure and additionally enhanced development of the mitochondria and smooth endoplasmic reticulum as well as formation of the microvilli (p less than 0.05). FSH significantly increased [125I]iodo-hCG binding and progesterone secretion relative to insulin-treated samples (p less than 0.001). Combined treatment with insulin and FSH markedly increased gap junction and microvilli formation and enhanced the development of the smooth endoplasmic reticulum and the Golgi complex relative to treatment with either hormone alone (p less than 0.05). Additionally, the combined treatment produced larger mitochondria with tubular christae. Consistent with the morphological development, the combined treatment of insulin and FSH significantly increased progesterone secretion and [125I]iodo-hCG binding (p less than 0.001). Autoradiographic analysis showed that aggregated cells in general exhibited higher LH/hCG receptor density than nonaggregated cells, and a significantly higher overall receptor density compared to nonaggregated cells or to cells treated either with insulin or FSH alone. Our results indicate that insulin and FSH facilitate morphological differentiation of the granulosa cell in a synergistic manner, stimulating gap junctions and microvilli formation and enhancing development of the mitochondria, endoplasmic reticulum, and Golgi complex.(ABSTRACT TRUNCATED AT 400 WORDS)     

Isolation of a vesicular intermediate in the cell-free transfer of membrane from transitional elements of the endoplasmic reticulum to Golgi apparatus cisternae of rat liver

Preparations enriched in part-smooth (lacking ribosomes), part-rough (with ribosomes) transitional elements of the endoplasmic reticulum when incubated with ATP plus a cytosol fraction responded by the formation of blebbing profiles and approximately 60-nm vesicles. The 60-nm vesicles formed resembled closely transition vesicles in situ considered to function in the transfer of membrane materials between the endoplasmic reticulum and the Golgi apparatus. The transition elements following incubation with ATP and cytosol were resolved by preparative free-flow electrophoresis into fractions of differing electronegativity. The main fraction contained the larger vesicles of the transitional membrane elements, while a less electronegative minor shoulder fraction was enriched in the 60-nm vesicles. If the vesicles concentrated by preparative free-flow electrophoresis were from material previously radiolabeled with [3H]leucine and then added to Golgi apparatus immobilized to nitrocellulose, radioactivity was transferred to the Golgi apparatus membranes. The transfer was rapid (T1/2 of about 5 min), efficient (10-30% of the total radioactivity of the transition vesicle preparations was transferred to Golgi apparatus), and independent of added ATP but facilitated by cytosol. Transfer was specific and apparently unidirectional in that Golgi apparatus membranes were ineffective as donor membranes and endoplasmic reticulum vesicles were ineffective as recipient membranes. Using a heterologous system with transition vesicles from rat liver and Golgi apparatus isolated from guinea pig liver, coalescence of the small endoplasmic reticulum-derived vesicles with Golgi apparatus membranes was demonstrated using immunocytochemistry. Employed were polyclonal antibodies directed against the isolated rat transition vesicle preparations. When localized by immunogold procedures at the electron microscope level, regions of rat-derived vesicles were found fused with cisternae of guinea pig Golgi apparatus immobilized to nitrocellulose strips. Membrane transfer was demonstrated from experiments where transition vesicle membrane proteins were radioiodinated by the Bolton-Hunter procedure. Additionally, radiolabeled peptide bands not present initially in endoplasmic reticulum appeared following coalescence of the derived vesicles with Golgi apparatus. These bands, indicative of processing, required that both Golgi apparatus and transition vesicles be present and did not occur in incubated endoplasmic reticulum preparations or on nitrocellulose strips to which no Golgi apparatus were added.(ABSTRACT TRUNCATED AT 400 WORDS)     

Morphology of the bovine epididymis

The epididymis of the bull was divided into six regions, and morphological differences between regions were studied. The epithelium of all regions contained four cell types: principal and basal epithelial cells, and intraepithelial lymphocytes and macrophages. The epithelium of regions II-V also contained a few apical cells. Principal cells of all regions possessed an endocytotic apparatus including stereocilia underlain by canaliculi, coated vesicles, and subapical vacuoles (up to 1 micron in diameter); however, large vacuoles with a flocculent content and multivesicular bodies (up to 5 microns in diameter) were most numerous in regions II, III, and IV. The unique features of principal cells of region I were the presence of well-developed Golgi bodies, few lipid droplets, and whorls of smooth endoplasmic reticulum in the supranuclear cytoplasm. Numerous mitochondria, distended cisternae of rough endoplasmic reticulum, and dense granules characterized the infranuclear cytoplasm of the principal cells of regions II-VI; however, these features were more developed in region V. Apical cells were characterized by the apical location of the nucleus, many mitochondria in the apical cytoplasm, and few microvilli at the luminal border. Basal cells with few cytoplasmic lipid droplets were present throughout the length of the epididymis but appeared more numerous in region V. Intraepithelial lymphocytes were present at all levels of the epithelium but were never seen in the lumen. Intraepithelial macrophages containing heterogeneous granules, eccentric nuclei, and pseudopods were invariably seen near the basal area of the epithelium in all regions. These observations are discussed in an effort to define the role of each cell type in the epididymal epithelium.     

Ultrastructure of the indifferent gonad in male and female pig embryos.

Pig embryos aged 24 days were obtained from artifically inseminated sows for ultrastructural study of the indifferent gonads. Sex was identified by chromosome analysis. The gonads are composed in both sexes of three different tissues: the surface epithelium, the gonadal blastema and the mesenchyme. The surface epithelial cells contained elongate mitochondria, granular endoplasmic reticulum, free polysomes, the Golgi complex, fine filaments and coated vesicles. The primitive cords were continuous with the surface epithelium and the interior of the gonad was occupied by blastema cells. They had prominent nucleoli, elongate mitochondria, granular endoplasmic reticulum, the Golgi complex, free polysomes, some lipid droplets and occasionally circular smooth membrane profiles resembling the agranular endoplasmic reticulum. Individual primordial germ cells were seen in all parts of the gonad. They were roundish with prominent nucleoli, globular mitochondria, granular endoplasmic reticulum, free polysomes, the Golgi complex, coated vesicles, lipid droplets and dense bodies. Degenerating cells and cells having pseudopods were also encountered. In comparison to the gonad at the age of 22 days, the primordium had grown into a longitudinal roundish protrusion and the number of primoridal germ cells had increased. Histological and ultrastructural observations showed that the pig gonads at the age of 24 days were similar in both sexes.     

ISOLATION OF A GOLGI APPARATUS-RICH FRACTION FROM RAT LIVER : II. Enzymatic Characterization and Comparison with Other Cell Fractions

Enzymatic activities associated with Golgi apparatus-, endoplasmic reticulum-, plasma membrane-, mitochondria-, and microbody-rich cell fractions isolated from rat liver were determined and used as a basis for estimating fraction purity. Succinic dehydrogenase and cytochrome oxidase (mitochondria) activities were low in the Golgi apparatus-rich fraction. On the basis of glucose-6-phosphatase (endoplasmic reticulum) and 5'-nucleotidase (plasma membrane) activities, the Golgi apparatus-rich fraction obtained directly from sucrose gradients was estimated to contain no more than 10% endoplasmic reticulum- and 11% plasma membrane-derived material. Total protein contribution of endoplasmic reticulum, mitochondria, plasma membrane, microbodies (uric acid oxidase), and lysosomes (acid phosphatase) to the Golgi apparatus-rich fraction was estimated to be no more than 20–30% and decreased to less than 10% with further washing. The results show that purified Golgi apparatus fractions isolated routinely may exceed 80% Golgi apparatus-derived material. Nucleoside di- and triphosphatase activities were enriched 2–3-fold in the Golgi apparatus fraction relative to the total homogenate, and of a total of more than 25 enzyme-substrate combinations reported, only thiamine pyrophosphatase showed a significantly greater enrichment.     

The vas deferens of the spider crab,Libinia emarginata

Sperm enter the anterior vas deferens individually in the spider crab male. There they become surrounded by secretion products from the cells of the vas deferens, and are compartmentalized into spermatophores of varying size. The anterior vas deferens can be divided into three regions. The epithelium of the anterior vas deferens varies regionally from low to high columnar. The cytoplasm contains vast arrays of rough endoplasmic reticulum and Golgi complexes but few mitochondria. Intercellular spaces contain septate junctions, gap junctions and vesicles. Once the spermatophores have been formed in the anterior vas deferens, they are moved posteriorly to the middle vas deferens where they are stored and surrounded by seminal fluids. The epithelial cells of the middle vas deferens contain large amounts of rough endoplasmic reticulum and Golgi complexes. Numerous micropinocytotic vesicles appear, forming at the cell surface and within the apical cytoplasm. Their suggested function is the resorption of secretion products of the anterior vas deferens which initiated compartmentalization of the spermatozoa into spermatophores. The posterior vas deferens functions primarily as a storage center for spermatophores until they are released at the time of copulation. Seminal fluid surrounding the spermatophores is produced in this region as well as in the middle vas deferens. The cells of this region contain vast arrays of vesicular rough endoplasmic reticulum and Golgi complexes. The cells are multinucleate. Microtubules are numerous throughout the length of the cells and appear to insert on the plasma membrane.     

Wandering cells in the nephron of the mudskipper Periophthalmus koelreuteri (Pallas)

Wandering cells that infiltrate between the principal cells of the nephron of the mudskipper Periophthalmus koelreuteri were examined by transmission electron microscope. These cells were found at various levels between the tubule cells and were more abundant in the proximal and collecting segments. These cells have cytoplasmic processes and large spherical nuclei. Their cytoplasm appears electron dense and contains many lysosomes, rough endoplasmic reticulum, free ribosomes, some mitochondria and Golgi profiles. Their ultrastructural features indicate that they may be phagocytic.     

A fine-structural analysis of mouse molar odontoblast maturation.

The first mandibular molars of the Swiss albino mice, 1 through 4 days of age, were fixed in glutaraldehyde or Karnovsky's fixative. The tissues were postfixed in OSO4, dehydrated and embedded in Epon. The prepolarizing, polarizing and secretory odontoblasts were described. The prepolarizing cells, located in the vicinity of the cervical loop, were mesenchymal-like in morphology. The cells of the polarizing stage possessed organelles indicative of protein synthesis. The nucleus was located proximally. Aperiodic fibers were evident in the wide basement membrane. The secretory odontoblasts were long, slender, polarized cells closely adjoining one another. Each odontoblast possessed six morphologically discernible regions: (1) an infranuclear region, limited in size and containing few cellular organelles; (2) a nuclear region, housing the oval nucleus and a few associated lamellae of rough endoplasmic reticulum as well as a limited number of mitochondria; (3) a supranuclear rough endoplasmic reticulum region, possessing an abundance of these organelles as well as some mitochondria and secretory vesicles; (4) a Golgi region, occupying the middle third of the cell, housing the elements of an extensive Golgi apparatus which was surrounded by peripherally located profiles of rough endoplasmic reticulum; additionally, this region contained smooth endoplasmic reticulum, mitochondria, numerous secretory granules and vesicles and occasional intracellular collagen fibers; (5) an apical rough endoplasmic reticulum region, containing a rough endoplasmic reticulum component that was less extensive than its supranuclear counterpart; in addition, this region was the one richest in mitochondria and contained a plethora of secretory vesicles and granules; (6) the odontoblastic process, a region mostly void of organelles, containing various secretory products, some of which appeared to be in the process of being released extracellularly into the surrounding dentin matrix.     

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 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.     

LYSOSOMES AND GERL IN NORMAL AND CHROMATOLYTIC NEURONS OF THE RAT GANGLION NODOSUM

The rat ganglion nodosum was used to study chromatolysis following axon section. After fixation by aldehyde perfusion, frozen sections were incubated for enzyme activities used as markers for cytoplasmic organelles as follows: acid phosphatase for lysosomes and GERL (a Golgi-related region of smooth endoplasmic reticulum from which lysosomes appear to develop) (31–33); inosine diphosphatase for endoplasmic reticulum and Golgi apparatus; thiamine pyrophosphatase for Golgi apparatus; acetycholinesterase for Nissl substance (endoplasmic reticulum); NADH-tetra-Nitro BT reductase for mitochondria. All but the mitochondrial enzyme were studied by electron microscopy as well as light microscopy. In chromatolytic perikarya there occur disruption of the rough endoplasmic reticulum in the center of the cell and segregation of the remainder to the cell periphery. Golgi apparatus, GERL, mitochondria and lysosomes accumulate in the central region of the cell. GERL is prominent in both normal and operated perikarya. Electron microscopic images suggest that its smooth endoplasmic reticulum produces a variety of lysosomes in several ways: (a) coated vesicles that separate from the reticulum; (b) dense bodies that arise from focal areas dilated with granular or membranous material; (c) "multivesicular bodies" in which vesicles and other material are sequestered; (d) autophagic vacuoles containing endoplasmic reticulum and ribosomes, presumably derived from the Nissl material, and mitochondria. The number of autophagic vacuoles increases following operation.     

内质网及其标志酶在离体培养脊髓神经元中的发育变化

In an attempt to elucidate the relationship between synapse formation and cell development, the morphology and cytochemistry of the endoplasmic reticulum and its enzymic marker, glucose-6-phosphatase (G-6-Pase), in cultured mouse spinal neurons were investigated ultrastructurally. It was found that in the early period of the development, neurons were characterized by scarceness of organelles; only a few of granular or agranular endoplasmic reticulum and mitochondria were seen. The endoplasmic reticulum and nuclear envelope were packed specifically with G-6-Pase resection product but the product was weak. After a period of culture, most of the neurons had well-developed endoplasmic reticulum, Golgi apparatus, mitochondria and microtubules, etc. The Golgi apparatus was relatively large, having some cisternae associated with vesicles. Either concave of convex face of the saccules was labeled by thiamine pyrophosphatase (TPPase) specifically. GERL, labeled by cytidine monophosphatase (CMPase), was also seen close to the inner or outer face of some Golgi apparatus. The endoplasmic reticulum at this stage was distributed throughout the cytoplasm, including that in dendrites; its enzyme marker (G-6-Pase) localized consistently within the lumen of all endoplasmic reticulum, nuclear space and subsurface cisternae, and frequently in the concave saccules of the Golgi apparatus. After a long-term culture, some neurons became "aged". The endoplasmic reticulum cisternae enlarged and G-6-Pase reaction reduced. Along with the neuronal development, especially maturation of the endoplasmic reticulum and its enzymic marker, synapse formation was begun at the neuropile area. The axo-dendritic synapses always occurred between the axonal terminals and dendrites where the endoplasmic reticulum had showed positive G-6-Pase reactions. Considering the fact, it suggests that the appearance and change of these specific enzymes may be related to the maturation of the neurons in vitro, and also related to the synapse formation between neurons.     

Cell-free transfer and sorting of membrane lipids in spinach

Summary The donor and acceptor specificity of cell-free transfer of radiolabeled membrane constituents, chiefly lipids, was examined using purified fractions of endoplasmic reticulum, Golgi apparatus, nuclei, plasma membrane, tonoplast, mitochondria, and chloroplasts prepared from green leaves of spinach. Donor membranes were radiolabeled with [¹⁴C]acetate. Acceptor membranes were unlabeled and immobilized on nitrocellulose filters. The assay was designed to measure membrane transfer resulting from ATP-and temperature-dependent formation of transfer vesicles by the donor fraction in solution and subsequent attachment and/or fusion of the transfer vesicles with the immobilized acceptor. When applied to the analysis of spinach fractions, significant ATP-dependent transfer in the presence of cytosol was observed only with endoplasmic reticulum as donor and Golgi apparatus as acceptor. Transfer in the reverse direction, from Golgi apparatus to endoplasmic reticulum, was only 0.2 to 0.3 that from endoplasmic reticulum to Golgi apparatus. ATP-dependent transfers also were indicated between nuclei and Golgi apparatus from regression analysis of transfer kinetics. Specific transfer between Golgi apparatus and plasma membrane and, to a lesser extent, from plasma membrane to Golgi apparatus was observed at 25°C compared to 4°C but was not ATP plus cytosol-dependent. All other combinations of organelles and membranes exhibited no ATP plus cytosol-dependent transfer and only small increments of specific transfer comparing transfer at 37°C to transfer at 4°C. Thus, the only combinations of membranes capable of significant cell-free transfer in vitro were those observed by electron microscopy of cells and tissues to be involved in vesicular transport in vivo (endoplasmic reticulum, Golgi apparatus, plasma membrane, nuclear envelope). Of these, only with endoplasmic reticulum (or nuclear envelope) and Golgi apparatus, where transfer in situ is via 50 to 70 nm transition vesicles, was temperature-and ATP-dependent transfer of acetatelabeled membrane reproduced in vitro. Lipids transferred included phospholipids, mono-and diacylglycerols, and sterols but not triacylglycerols or steryl esters, raising the possibility of lipid sorting or processing to exclude transfer of triacylglycerols and steryl esters at the endoplasmic reticulum to Golgi apparatus step.     

Morphometric analysis of the pineal complex of the golden hamster over a 24-hour light:dark cycle: II. The deep pineal in untreated and optically enucleated animals

The deep pineal gland of golden hamsters was morphometrically analyzed and quantitatively compared with the superficial pineal under a 14:10 lighting regime and following blinding. The deep pineal comprised 6-10% of the total pineal parenchymal tissue. Pinealocytes of the deep gland were smaller than the cells of the superficial pineal and showed a greater percent volume of Golgi bodies, rough endoplasmic reticulum, and dense-cored vesicles. Twenty-four-hour rhythms in nucleoli and Golgi bodies were found in deep pinealocytes. These rhythms were out of phase with comparable rhythms in the superficial pineal gland, suggesting that distinct subpopulations of pinealocytes are present within the respective parts. Blinding resulted in decreased nuclear and nucleolar volume, while the amount of smooth endoplasmic reticulum, Golgi bodies, dense bodies, and dense-cored vesicles increased significantly. Marginal increases were seen in mitochondria and lipid droplets. The greater abundance of those organelles involved in synthesis and secretion suggests enhanced cellular activity after blinding. Many of the morphological responses are similar to alterations in the pinealocytes of the superficial pineal following optic enucleation.     

Ultrastructure of spermatogenesis in Cerastoderma glaucum (Cardiacea) and Spisula subtruncata (Mactracea)

Summary

In Cerastoderma glaucum, Sertoli cells are rich in lipids, glycogen and lysosomes, and premeiotic cells exhibited nuage, a prominent Golgi complex and endoplasmic reticulum cisternae encircling the nucleus. The Golgi complex gives rise to proacrosomal vesicles during mid-spermiogenesis, and the round acrosomal vesicle, with a dense fibrillar core, migrates laterally while linked to the plasma membrane as it develops the subacrosomal material. In its final position, the vesicle becomes cap-shaped (0.6 μm) and differentiates into apical light and basal dense regions. The elongated and helicoidal nucleus (8–9.9 μm) has a thin tip (0.3 μm) that invades the subacrosomal space, and in the midpiece (0.8 μm) two of the four mitochondria extend laterally to the nucleus (1.5–2.1 μm). In Spisula subtruncata, Sertoli cells are rich in lipids, glycogen and phagocytosed sperm. Premeiotic cells exhibit nuage, a prominent Golgi complex that gives rise to proacrosomal vesicles from the leptotene stage and a flagellimi that is extruded at zygotene. The acrosomal vesicle forms during the round spermatid stage and differentiates into a large and dense basal region and an apical light region. It then migrates while linked to the plasma membrane by its apical pole. Development of the subacrosomal perforatorium is associated with nuage materials and endoplasmic reticulum vesicles. The mature cap-shaped (0.6 μm) acrosomal vesicle exhibits a large apical and irregular region with floccular contents and a basal dense region. The round nucleus becomes barrel-shaped (1.5 μm) and the midpiece (0.8 μm), with four mitochondria, contains a few glycogen particles.     

The ultrastructure of developing wings in the giant silkmoth, Hyalophora cecropia. II. Scale-forming and socket-forming cells

In wings of the giant silkmoth, Hyalophora cecropia, scale-forming and socket-forming cells are first observed on day four of pharate adult development. Scale-forming cells appear synthetically active when they are first observed, for their basal region is filled with huge stacks of polyribosome-studed lamellate endoplasmic reticulum, numerous Golgi complexes containing secretory vesicles and many elongated mitochondria. During later development, some of these organelles diminish in number. Neck and scale regions are predominantly filled with longitudinally oriented microtubules and microfibril bundles, suggesting that their function is one of transport rather than synthesis. The scales originate as finger-like projections of the cell body. They subsequently elongate, flatten out and deposit a cuticle which has a surface differing somewhat from that in other lepidopterans. It consists of longitudinal ridges (1.8-2.4 μ apart), transverse ribs (0.6-1.0 μ apart) and microribs (0.10-0.13 μ apart). Socket-forming cells produce a socket around the neck region of each scale-forming cell. The socket differentiates into several morphologically distinct regions: an apical fibrillar region, a ribosomal region, a mitochondrial-microtubular region and a basal fibrillar region. The absence of polyribosome-studded lamellae of endoplasmic reticulum and Golgi complexes suggests that its primary function is not biosynthesis but support and protection of the scale.     

Intracellular transport of albumin through the secretory apparatus of rat liver parenchymal cells. An immunocytochemical study

The fine structural localization of albumin in rat liver parenchymal cells was determined by an improved immunocytochemical method and serial sectioning. Albumin in the secretory apparatus of the parenchymal cells was present in segments of the rough endoplasmic reticulum, interrupted with negative segments, in transport vesicles, Golgi saccules, finely anastomosed tubules and vesicles on the trans side of the Golgi complex, and in secretion granules. Horizontally sectioned Golgi saccules contained lipoprotein particles on one side and albumin on the other side. After transport, the vesicles that contained albumin fused with the so-called rigid lamellae on the trans-side of the Golgi complex. Ultrathin serial sections revealed no true structural continuity between the endoplasmic reticulum and the cis-aspect of the Golgi complex. We concluded that secretory proteins are transported from the endoplasmic reticulum to the Golgi complex by transport vesicles that bud from the endoplasmic reticulum and fuse with the Golgi saccules. These vesicles fuse regularly with the Golgi saccules on the cis-side and occasionally with tubular elements on the trans-aspect that may belong to the so-called GERL.     

Mitotic Golgi fragments in HeLa cells and their role in the reassembly pathway

Immunoelectron microscopy and stereology were used to identify and quantitate Golgi fragments in metaphase HeLa cells and to study Golgi reassembly during telophase. On ultrathin frozen sections of metaphase cells, labeling for the Golgi marker protein, galactosyltransferase, was found over multivesicular Golgi clusters and free vesicles that were found mainly in the mitotic spindle region. The density of Golgi cluster membrane varied from cell to cell and was inversely related to the density of free vesicles in the spindle. There were thousands of free Golgi vesicles and they comprised a significant proportion of the total Golgi membrane. During telophase, the distribution of galactosyltransferase labeling shifted from free Golgi vesicles towards Golgi clusters and the population of free vesicles was depleted. The number of clusters was no more than in metaphase cells so the observed fourfold increase in membrane surface meant that individual clusters had increased in size. More than half of these had cisterna(e) and were located next to "buds" on the endoplasmic reticulum. Early in G1 the number of clusters dropped as they congregated in the juxtanuclear region and fused. These results show that fragmentation of the Golgi apparatus yields Golgi clusters and free vesicles and reassembly from these fragments is at least a two-step process: (a) growth of a limited number of dispersed clusters by accretion and fusion of vesicles to form cisternal clusters next to membranous "buds" on the endoplasmic reticulum; (b) congregation and fusion to form the interphase Golgi stack in the juxtanuclear region.     

Ultrastructural changes in cauda epididymidal epithelial cell types of Azadirachta indica leaf treated rats

To assess if cauda epididymis is a target for the effect of A. indica leaves, Wistar strain male albino rats were administered (po) A. indica leaves (100 mg/rat/day for 24 days). Transmission electron microscopic analysis revealed that in the cauda epididymal epithelium the nuclei of principal cells were enlarged and the number of coated micropinocytotic vesicles of the apical cytoplasm decreased. Microvilli were missing and mitochondrial cristae and Golgi complex were highly disrupted. The cytoplasm was abounding with lysosomal bodies. The clear cells increased in perimeter and their nuclei increased in size and contained lesser chromatin. The nuclear membrane bulged out. The cytoplasm was vacuolized. Further, there was decrease in size of the lipid droplets, mitochondria, Golgi complex, endoplasmic reticulum and there was accumulation of lysosomal bodies. The changes in the principal and clear cells appear to be due to the effect of the hypoandrogen status caused by treatment with A. indica leaves and a direct action on the epididymal epithelium.     

Annulate lamellae and whorl bodies in the diffuse supraoptic nucleus of the hamster

The ultrastructure of neurons of the diffuse supraoptic nucleus of the hamster has been studied. These neurons show two specializations of the endoplasmic reticulum: annulate lamellae and whorl bodies. From one to three whorl bodies are found in the same neuron. The annulate lamellae and the whorl body cisterns are continuous with the cisterns of the rough endoplasmic reticulum. These neurons present an extraordinarily developed rough endoplasmic reticulum, small mitochondria, neurosecretory vesicles and a Golgi complex filled with electron-dense material. Astrocytic processes of different thickness surround the neurosecretory cells.