Arrays Of Rough Endoplasmic Reticulum Research Articles

Labellar anatomy and secretion in Bulbophyllum Thouars (Orchidaceae: Bulbophyllinae) sect. Racemosae Benth. & Hook. f.

Floral secretions are common in Bulbophyllum Thouars, and the labella of a number of Asian species are said to produce secretions rich in lipids that act as food rewards for insect pollinators. Although some of these reports are based on simple histochemical tests, a much greater number are anecdotal and, hitherto, neither the ultrastructure of the labellum nor the secretory process has been investigated in detail. Furthermore, sophisticated histochemical approaches have generally not been applied. Here, both the labellar structure and the secretory process are investigated for four species of Asian Bulbophyllum sect. Racemosae Benth. & Hook. f., namely Bulbophyllum careyanum (Hook.) Spreng., B. morphologorum Kraenzl., B. orientale Seidenf. and B. wangkaense Seidenf., and compared with those of unequivocal lipid-secreting orchids. Labellar, secretory tissue was investigated using light microscopy, scanning electron microscopy, transmission electron microscopy and histochemistry. The adaxial median longitudinal groove of the labellum contained secretory tissue comprising palisade-like epidermal cells, similar to those of certain lipid-secreting Oncidiinae Benth. However, these cells and their secretions gave positive results mainly for protein and mucilage, and their organelle complement was consistent with that of cells involved in protein and mucilage synthesis. Sub-cuticular accumulation of secretion resulted in cuticular distension and blistering. The sub-epidermal layer of isodiametric parenchyma contained starch and, like the epidermal cells, ultrastructure consistent with mucilage synthesis. Lipids were mainly confined to the cuticle, and hardly any intracellular lipid droplets were observed. It is proposed that mucilage is produced by dictyosomes present in the palisade-like epidermal cells. Mucilage precursors may also be produced by these same organelles in sub-epidermal cells and are thought to pass along the symplast via plasmodesmata into the adjoining palisade-like secretory cells, which contain abundant arrays of rough endoplasmic reticulum. Here, they become chemically modified and form a protein-rich, mucilaginous secretion that, following vesicle-mediated transport across the cytoplasm, traverses the cell wall and accumulates in blisters formed from the distended cuticle. Rupture of these blisters releases the secretion onto the labellar surface. However, in certain species, there is some evidence that the secretion may traverse the cuticle via cuticular pores, and micro-channels may permit the passage of fragrance. Hydrolysis of sub-epidermal starch probably generates the carbohydrate and, together with mitochondria, much of the energy required for the secretory process. This anatomical organization resembles that found in certain lipid-secreting, Neotropical species of Bulbophyllum and Oncidiinae, but since the chemical composition of their secretions is different, and these taxa occur on a separate continent and have different insect pollinators, parallelism of floral anatomy is likely.

Leukemia in a Patient With Multiple Myeloma

Laboratory Evaluation Complete blood count at the time of admission revealed a normal hemoglobin, platelet count, and white blood cell count. However, the differential white blood cell count revealed 59% lymphoplasmacytic cells. Peripheral blood smear examination [I1] revealed a predominance of lymphocytes with plasmacytoid differentiation. Flow cytometric analysis of these cells revealed expression of CD38 and CD138 with cytoplasmic lambda light chain restriction [F1]. Neither CD20 nor other B lymphocyte antigens were expressed. Molecular cytogenetic studies by fluorescence in situ hybridization (FISH) using DNA probes for loci at 11q23 (ATM), 13q14.3 (RB1), 13q34, and 17p13.1 (p53) revealed duplication/trisomy for the 11q23/ATM locus and concomitant deletion of targeted loci on chromosome 13 (13q14.3/RB1 and 13q34) [I2]. Fluorescence in situ hypridization analyses using probes for chromosomes 6, 9, and 12 were within normal limits without clonal abnormalities. No conventional cytogenetic studies were performed. Urine and serum immunoelectrophoresis, skeletal survey, and bone marrow biopsy were performed. The 24 hour total urine protein was 3,689 mg/dL. Serum and urine electrophoresis and immunofixation studies revealed monoclonal lambda light chain with free lambda light chains in urine. Most of the M component was in the urine and was comprised of lambda light chain which constituted 62.5% of the total urine protein. Imaging studies revealed osteolytic lesions in the femur and humerus. The bone marrow biopsy was hypercellular with greater than 95% lymphoplasmacytic cells [I3], most of which had small nucleoli. Tumor cells expressed CD38 [I4] and cytoplasmic lambda light chain on immunoperoxidase staining. Electron microscopy of tumor cells from the peripheral blood revealed irregular shaped nuclei, a high N:C ratio, scattered mitochondria, and numerous parallel arrays of rough endoplasmic reticulum [I5]. The cell surface revealed thin, short filopodia. The laboratory and clinical findings were consistent with the diagnosis of plasma cell leukemia.

Cytochemical and ultrastructural examination of apoptotic odontoclasts induced by bisphosphonate administration.

Since odontoclasts share similar characteristics with osteoclasts, this study has examined whether odontoclasts exhibit cytological alteration after treatment with bisphosphonate, which induces apoptosis of osteoclasts. After the administration of bisphosphonate to 6-day-old rabbits, many odontoclasts detached from the dentine surface of the deciduous teeth, resulting in the reduction of tartrate-resistant acid phosphatase (TRAP-ase) and immunoreactivity for cathepsin K. Transmission electron microscopy revealed a number of odontoclasts showing poorly developed or a lack of ruffled borders, a Golgi apparatus markedly reduced in size, and numerous cytoplasmic vesicles. The bisphosphonate-treated odontoclasts displayed fragmented DNA in the pyknotic nuclei evidenced by terminal deoxynucleotidyl-transferase-mediated dUTP-biotin nick-end labeling, indicating that bisphosphonate can induce apoptosis of the odontoclasts. Ultrastructural observations of the apoptotic odontoclasts revealed condensed heterochromatin at the margin of the nuclear envelope, assembled arrays of rough endoplasmic reticulum, and many vacuoles and vesicles. Some apoptotic odontoclasts showed ladder-like structures between the adjacent nuclear envelopes, enlargement of the nuclear envelopes, and the formation of a ribosome-like granular structure in the nuclei. Thus, odontoclasts are able to undergo apoptosis after bisphosphonate treatment; this results in cytological alterations, including reduced resorption activity and the inhibition of protein synthesis/transport as indicated by the diminished TRAPase and cathepsin K and the poorly developed Golgi apparatus, respectively. Nuclear alteration as evidenced by the appearance of ladder-like and ribosome-like structures was characteristic of apoptotic odontoclasts.

Histopathologic and ultrastructural alterations of white liver disease in sheep experimentally depleted of cobalt.

Many cobalt-deficient sheep develop liver lesions known as ovine "white liver" disease, but the etiology of these changes is controversial. It has been suggested that cofactors are required for development of liver damage in cobalt-deficient sheep. In this study, one group of lambs (n = 5) was fed a diet low in cobalt (4.5 micrograms/kg) while a group of control lambs (n = 4) received the same diet after it had been supplemented with cobalt (1000 micrograms/kg). All cobalt-depleted lambs had reduced growth rate, anorexia, lacrimation, and alopecia, and they eventually became emaciated (mean body weight at end of study: 83% of initial body weight). Plasma concentrations of bilirubin and serum activity of glutamate-oxaloacetate transferase were elevated in these animals, while plasma concentrations of vitamin B12 were reduced (less than 220 pmol/L from day 42). Fatty degeneration of the liver associated with reduced concentrations of vitamin B12 (14.5 pmol/g) was seen in these animals at necropsy at 196 days. Microscopic liver lesions included accumulation of lipid droplets and lipofuscin particles in hepatocytes, dissociation and necrosis of hepatocytes, and sparse infiltration by neutrophils, macrophages, and lymphocytes. Ultrastructural hepatocytic alterations included swelling, condensation and proliferation of mitochondria, hypertrophy of smooth endoplasmic reticulum, vesiculation and loss of arrays of rough endoplasmic reticulum, and accumulation of lipid droplets and lipofuscin granules in cytoplasm of hepatocytes. No liver lesions were seen in control lambs. The results of this study indicate that cofactors are not a prerequisite to development of hepatic damage in cobalt-deficient sheep. Reduced activities of the vitamin B12-dependent enzymes, methylmalonyl CoA mutase and methionine synthase, and lipid peroxidation are of likely pathogenetic importance in the development of the lesions.

Ultrastructural and Histomorphometric Evaluations of Gallium Nitrate on Bone in Nude Mice Bearing a Canine Adenocarcinoma (CAC-8) Model of Humoral Hypercalcemia of Malignancy

Gallium is a group IIIa transition metal that lowers serum calcium by an unknown mechanism and has been utilized in the treatment of cancer-associated hypercalcemia. The purpose of this study was to histomorphometrically investigate the ultrastructural effects of gallium nitrate on osteoclasts and osteoblasts in trabecular bone of normal nude mice and nude mice with humoral hypercalcemia of malignancy. Two groups of normal nude mice (n = 7 and n = 8, respectively) and two groups of hypercalcemic nude mice (n = 9) bearing a serially transplantable canine adenocarcinoma (CAC-8) were treated with vehicle or gallium nitrate. Osteoclasts were hypertrophied in vehicle-treated tumor-bearing nude mice as compared with vehicle-treated nontumor-bearing nude mice. Osteoclasts from tumor-bearing nude mice treated with gallium nitrate were significantly decreased in size and had fewer intracytoplasmic vesicles as compared with osteoclasts from vehicle-treated tumor-bearing nude mice. Degenerate osteoclasts, characterized by pyknotic nuclei and increased cytoplasmic vacuolation, were observed in both groups of gallium-treated nude mice. Osteoblasts from vehicle-treated tumor-bearing nude mice were hypertrophied and had extensive lamellar arrays of rough endoplasmic reticulum as compared with osteoblasts from vehicle-treated nontumor-bearing nude mice. Osteoblasts in gallium-treated nude mice (tumor-bearing and nontumor-bearing) were small and flattened with poorly developed cytoplasmic organelles. This investigation demonstrated that osteoclasts and osteoblasts in nude mice treated with gallium nitrate had ultrastructural evidence of decreased metabolic and functional activity. The results suggest that gallium nitrate lowers serum calcium by inhibiting osteoclastic bone resorption.

Plasmodial tapetum and pollen wall development inButomus umbellatus (Butomaceae)

This report describes the ultrastructural development of plasmodial tapetum and pollen wall of Butomus umbellatus. The tapetum contains extensive arrays of rough endoplasmic reticulum, vesicles from which are responsible for the formation of sporopollenin‐like bodies. The tapetum is also involved in the formation of other forms of sporopollenin precursors. Development of pollen wall continues after microspores are released from their callosic walls; they are then enclosed by plasmodial tapetum. The activity and products of the plasmodial tapetum show substantial correlation with pollen wall development, particularly ektexine formation. In B. umbellatus, the tapetum intrudes into the anther locule at early microspore stage. This timing of plasmodial intrusion occurs at a later stage of pollen development as compared to those in the advanced monocotyledons. We report the rough endoplasmic reticulum origin of sporopollenin‐like bodies and their occurrence in the plasmodial tapeta of B. umbellatus.

Effects of Humoral Hypercalcemia of Malignancy and Gallium Nitrate on Thyroid C Cells in Nude Mice: Immunohistochemical and Ultrastructural Investigations

Immunohistochemical and ultrastructural investigations of thyroid C cells were conducted in male nude (athymic) mice bearing a serially transplantable canine adenocarcinoma (CAC-8) model of humoral hypercalcemia of malignancy following subcutaneous administration of gallium nitrate. The following four groups were investigated: 1) vehicle-treated non-tumor-bearing control mice; 2) non-tumor-bearing mice treated with gallium nitrate; 3) vehicle-treated hypercalcemic mice bearing CAC-8; and 4) CAC-8 tumor-bearing mice treated with gallium nitrate. Gallium nitrate-treated tumor-bearing mice had a significant decrease in serum calcium as compared with tumor-bearing controls. C cells of non-tumor-bearing mice stained intensely for calcitonin and calcitonin gene-related peptide and weakly for chromogranin A and neuron-specific enolase. In C cells of both vehicle- and gallium-treated tumor-bearing mice, immunoreactive staining was decreased for calcitonin, calcitonin gene-related peptide, and chromogranin A, whereas there was a moderate increase in staining for neuron-specific enolase. Ultrastructurally, thyroid C cells in hypercalcemic tumor-bearing control and gallium-treated mice were hypertrophic and markedly degranulated as compared with those of non-tumor-bearing controls. Hypertrophic C cells contained few mature secretory granules, a well-developed Golgi apparatus, and lamellar arrays of rough endoplasmic reticulum. There was no evidence of C-cell hyperplasia. Immunohistochemical and ultrastructural findings revealed that C cells in mice with cancer-associated hypercalcemia were primarily in the actively synthesizing phase of the secretory cycle and had diminished immunoreactivity for calcitonin, calcitonin gene-related peptide, and chromogranin A.(ABSTRACT TRUNCATED AT 250 WORDS)

Cellular differences in ring glands of flesh fly pupae as a consequence of diapause programming

The ultrastructure of the ring gland (corpus cardiacum (CC), prothoracic gland (PG) and corpus allatum (CA)) was examined in diapausing and nondiapausing flesh fly pupae. The diapause developmental state, which is environmentally regulated and coordinated by the brain-ring gland complex, is associated with differences in the ultrastructure of PG and CA cells but not in the CC. During diapause the PG and CA cells have extensive arrays of rough endoplasmic reticulum and spherical mitochondria. The PG cells also contain lipid droplets surrounded by an electron dense amorphous coat not seen in PG cells from nondiapausing pupae. In nondiapausing pupae, the PG and CA cells contain large amounts of ribosomes throughout the cytoplasm but very little rough endoplasmic reticulum and elongated mitochondria. The fact that ring glands from diapausing pupae readily incorporate 35S-methioninc indicates that the gland is actively synthesizing proteins, thus the contrasts in ring gland ultrastructure are not due to cellular quiescence during diapause but reflect fundamental cellular and physiological differences between the diapause and nondiapause developmental program.

Ultrastructural Heterogeneity of Epithelioid Cells in Cutaneous Organized Granulomas of Diverse Etiology

In organized granulomatous inflammation, activated macrophages terminally differentiate into epithelioid cells (ECs). By light microscopy, individual ECs appear similar, irrespective of the inciting agent. Ultrastructural analysis of a number of clinical and experimental granulomas in man and mice reveals, however, three distinct varieties of these cells. They are classified as follows: (1) EC-I cells containing a mixture of lysosomal-dense bodies and phagolysosomes and arrays of rough endoplasmic reticulum in the cytoplasm; (2) EC-II cells showing primarily a secretory mode with prominent Golgi bodies and rich arrangement of dilated rough endoplasmic reticulum with no phagocytic vacuoles; and (3) EC-III cells containing large multisized vesicles crowded throughout the cytoplasm and presently of unknown function. Although the unique appearance of these cells offers little diagnostic help, the cells do distribute differentially in different granulomas. The EC-I cells tend to predominate in infectious granulomas and where an excess of foreign material and debris is present. The EC-II cells are most characteristic of active sarcoidal granulomas, and the EC-III cells appear in chronic, long-standing granulomas. The heterogeneic nature of these cells seems to suggest their functions in granulomatous inflammation are not always the same.

Gonadotropes in a novel rat pituitary tumor cell line, RC-4B/C. Establishment and partial characterization of the cell line

An epithelial cell line (RC-4B/C) was established from a pituitary adenoma obtained from a 3-yr-old (ACI/fMai X F344/fMai)F1 male rat. Before Year 5 in vitro, RC-4B/C cells could not be viably recovered from cryogenic storage. Recovery of viable cells from cryogenic storage in Year 5 was associated with a more transformed phenotype, including the appearance of endogenous C-type rat retroviral particles. The ultrastructural appearance of the cells was similar to that of differentiated anterior pituitary cells; the cultured cells contained numerous, electron dense, secretory granules, Golgi complexes, and extended arrays of rough endoplasmic reticulum. Immunocytochemical study showed that all cell types present in the rat anterior pituitary gland were present in the cell line. The percentage of luteinizing hormone beta (LH beta) cells in the cell line was higher (19.9%) and that of growth hormone cells was lower (12.2%) than in normal male rat pituitary, whereas the cell line contained a comparable percentage of follicle stimulating hormone beta (FSH beta), prolactin (PRL), ACTH, and thyrotropin beta cells. Radioimmunoassay data demonstrated the PRL content of the cells was comparable to that of normal male rat pituitary gland, whereas the content of LH and FSH was 70- and 800-fold lower, respectively. Assay of specific receptor sites for gonadotropin releasing hormone (GnRH) using Scatchard plots of the data established the RC-4B/C cells contained GnRH receptor sites of the same affinity as in the pituitary gland, but of twofold lower capacity. These data suggest the RC-4B/C cell line warrants further study as a model for the induction and maintenance of the gonadotropic function of the pituitary gland.

Structure of the ovotestis and evidence for heterosynthetic incorporation of yolk precursors in the oocytes of the nudibranch mollusc, Spurilla neapolitana.

The ovotestis of Spurilla neapolitana consists of a series of spherical lobes, each of which is composed of radially arranged, sac-like acini or follicles. The male and female portions of each acinus are separated by ovarian follicle cells and testicular accessory cells. A thick basal lamina serves as a barrier between adjacent acini. The surface of each ovotestis lobe is covered by several layers of myoepithelial cells resting on a connective tissue layer. Developing oocytes are intimately associated with follicle cells except in the last stages of vitellogenesis. Follicle cells are characterized by the presence of extensive arrays of rough endoplasmic reticulum (RER) and Golgi complexes and may play a role in vitellogenesis. An ultrastructural analysis of vitellogenesis suggests that oocytes utilize both auto- and heterosynthetic mechanisms of yolk formation. Autosynthetsis is suggested by the activity of the Golgi complex and RER, while heterosynthesis is indicated by high levels of endocytotic activity by the oocyte. Follicle cell development and high endocytotic activity in the oocytes may be a reproductive adaptation to accelerate yolk synthesis, resulting in more rapid egg production.

Ultrastructural and cytochemical study on interactions between nutrient storage cells and gametogenesis in the mussel Mytilus edulis

The ultrastructural morphology of storage-cell breakdown and replenishment in Mytilus edulis is described for mussels collected at monthly intervals over a period of one year (September 1981 to October 1982) from a site in Cornwall, England. In addition cytochemical staining reactions at light and electron microscope levels are described for the storage cells and the Sertoli cells. The breakdown of adipogranular (ADG) cell components is believed to be a lysosomally-mediated process of controlled autolysis involving fusion of primary lysosomes with the protein granules. Increasing activity for lysosomal enzymes during ADG cell breakdown is demonstrated using quantitative cytochemistry. The presence of glycogen in vesicular connective tissue (VCT) cells is demonstrated using freeze-dried, formaldehyde-vapour-fixed tissue. The breakdown of VCT cells involves sequestration of glycogen from the central reserve into small cytoplasmic vesicles; subsequent release appears to be mediated by eccrine secretion. The presence of arylsulphatase activity in lysosomes within the peripheral cytoplasm of the VCT cells during the winter months indicates that glycogen breakdown may also be lysosomally mediated. The morphology of the Sertoli cells is described; during the early stages of spermatogenesis they are characterized by the presence of numerous lipid droplets which are depleted as development proceeds. Contact between Sertoli cells and developing spermatogonia is maintained by means of long septate junctions. Following spawning, the well developed lysosomal system is evident in the Sertoli cells and appears to be engaged in intracellular digestion of phagocytosed waste sperm and residual cytoplasm. Resorption of the products of gamete degeneration by the gonoduct epithelial cells is described. During regeneration, VCT cells appear to endocytose material; the ADG cells demonstrate extensive arrays of rough endoplasmic reticulum and are occasionally seen undergoing mitosis. A process involving loss of glycogen vesicles from the mantle epithelial cells by means of apocrine sections is described.

The motor trigeminal nucleus of the rat: Analysis of neuronal structure and the synaptic organization of noradrenergic afferents

The organization of the rat motor trigeminal nucleus (MTN) and the morphology of noradrenergic afferents terminating in this cranial motor nucleus were analyzed with light and transmission electron microscopy. Two morphologically distinct types of neurons are present in the MTN. Large multipolar neurons are the most prevalent cell type and are distributed uniformly throughout the nucleus. The morphology of these cells is identical to that of motor neurons described previously in both the brainstem and spinal cord. The neurons are characterized ultrastructurally by a light, organelle-rich cytoplasmic matrix containing numerous cisternal arrays of rough endoplasmic reticulum (RER) and a centrally placed spherical nucleus containing a single prominent nucleolus. Approximately 80% of the surface of these cells is contacted by axon terminals. The second major class of neuron consists of small spherical and fusiform cells that are located predominantly at the peripheral borders of the MTN. These cells are significantly smaller than motor neurons and exhibit only scattered axosomatic contacts. This small cell population appears to be composed of two distinct subclasses of neurons that probably represent interneurons and gamma motor neurons. The MTN neuropil contains four morphologically distinct classes of axon terminals that are characterized by either spherical or pleomorphic vesicles within cytoplasm that is lucent or dense. Quantitative morphometric analysis demonstrated differential distribution of each of the four terminal types upon motor neuron somata and dendrites. Intracerebral injection of 5-hydroxydopamine into the brainstem tegmentum immediately adjacent to the MTN labeled axon terminals containing spherical vesicles and a lucent axoplasmic matrix. Intracerebral injection of the neurotoxin 6-hydroxydopamine resulted in degeneration of the same terminal population and thus confirmed that noradrenaline-containing axons innervating the MTN exhibit a distinctive terminal morphology. The number of synaptic complexes exhibited by noradrenergic terminals did not differ significantly from other terminal populations in the MTN.

ULTRASTRUCTURAL LOCALIZATION OF PROLACTIN IN THE HUMAN PITUITARY PROLACTINOMAS AND ITS CHANGES BY BROMOCRIPTINE TREATMENT

Fourteen human prolactinomas, four of which received bromocriptine treatment, were studied by immunoelectron microscopy to observe the intracellular localization of prolactin (PRL). In the untreated cases two different patterns of PRL localization were noted. In the first type (Type I) PRL was seen in Golgi saccules, single stacks of rough endoplasmic reticulum (RER), and a few secretory granules and in the second type (Type II) it was present in the predominant parallel arrays of RER. Type II cells were observed more frequently in the cases with higher serum prolactin levels. In the treated cases with normalized serum prolactin levels, the tumor cells showed accumulation of secretory granules. This finding suggested secretory inhibition. RER and Golgi saccules were inconspicuous in these cells and this might indicate decreased production of PRL. In a case which was resistant to the bromocriptine treatment, most tumor cells were similar in ultrastructural localization of PRL to those cells in the untreated cases and this might suggest the lack of dopamine receptor.

Light and electron microscopic study of an avian pretectal nucleus, the lentiform nucleus of the mesencephalon, magnocellular division.

Using several light microscopic methods we have identified the lentiform nucleus of the mesencephalon, magnocellular division, by its position in the pretectum, its cellular composition, and its complement of retinal afferents and have distinguished it from neighboring structures. At the light microscopic level large neurons (approximately 30 X 21 microns) and small neurons (approximately 13 X 9 microns), which are more numerous, are seen interspersed among myelinated axons. The large neurons are generally ovoid and contain an eccentrically located nucleus and large clumps of Nissl-stained material. In the electron microscope the most notable feature of these neurons is the presence of ribosome rosettes and many parallel arrays of rough endoplasmic reticulum (RER). On the basis of cytological and ultrastructural features, we conclude that only one class of large neuron is present. Although in the light microscope the small neurons appear to be similar, at the ultrastructural level three neuron types have been distinguished: (1) ovoid shape with cytoplasm densely packed with organelles especially RER, (2) round shape with very little cytoplasm with few organelles, and (3) triangular shape with a pale cytoplasmic matrix with some RER. Subsurface membrane configurations are often seen in the somata of all neuron types. In addition, axon terminals, some containing flat vesicles, and other less frequent ones containing round vesicles are seen terminating on the somata of all neuronal cell types. In the neuropil, three types of presynaptic profiles can be identified. Two of these profiles are axodendritic and the third is dendrodendritic. The type R profile, which is often as large as 4 micron 2, is the most numerous, contains large round synaptic vesicles, and is often seen synapsing on several dendritic profiles. The type F profile contains flat vesicles and a relatively dense cytoplasm, and is smaller in area than type R. The third profile, which contains small clusters of pleiomorphic vesicles and apparently is dendritic, forms synapses with dendritic profiles. We propose that the type R axon terminals originate mostly from the retina and the type F mostly from the visual telencephalon.

Induction of plasmacytoid differentiation by phorbol ester in B-cell lymphoma cell lines bearing 8;14 translocations.

At nanomolar concentrations, phorbol 12-myristate 13-acetate induced differentiation in a human Epstein-Barr virus-negative B-cell line, JD 38, derived from an undifferentiated lymphoma and containing an 8;14 translocation. The changes induced by phorbol 12-myristate 13-acetate were consistent with differentiation towards plasma cells and included (i) a marked increase (30-fold) in IgM secretion; (ii) a decrease in the nuclear/cytoplasmic ratio associated with the development of a single prominent nucleolus instead of multiple nucleoli; (iii) the development of parallel arrays of rough endoplasmic reticulum, eccentric nuclei, and marginated heterochromatin; (iv) a reduction in the expression of surface markers, including common acute lymphoblastic leukemia antigen, IgM, and C3 receptors. Essentially all cells showed plasmacytoid differentiation, although the degree varied. Rare cells (less than 1%) appeared to be terminally differentiated into plasma cells. The increase in secreted IgM was preceded by a small increase in mu-chain RNA, with an increase in the ratio of secreted to membrane form. A small increase in c-myc RNA was also detected with differentiation. This might reflect coordinate regulation of the transcription of immunoglobulin and the translocated c-myc gene. Thus, the maturational arrest of this lymphoma cell line can be overcome with phorbol 12-myristate 13-acetate, indicating that translocation of the c-myc gene does not permanently block the capacity for differentiation. Further, this gene continues to be expressed to at least the same level during cell maturation. Similar ultrastructural changes were induced by phorbol 12-myristate 13-acetate in four of seven additional lines studied.

Role of ovarian follicle cells in vitellogenesis and oocyte resorption inCapitella sp. I (Polychaeta)

Capitella sp. I has a short generation time, is polytelic and produces broods of relatively large, yolky eggs at intervals of as short as 5–7 d at 20°C. The follicle cells surrounding vitellogenic oocytes in the medial portion of the ovary contain large nuclei, extensive arrays of rough endoplasmic reticulum and Golgi complexes. The coelomic surfaces of follicle cells in the outer layer are covered by blade-like microvilli, which project into the coelom. In the dorsal and lateral portions of the ovary, where mature oocytes are found, the follicle cells are covered by flat, stellate-shaped, peritoneal cells that resemble the podocytes of many invertebrate excretory organs and of the mammalian glomerulus. Changes occurring in the ovary during resorption of oocytes in the middle to advanced stages of vitellogenesis are described. Oogonia and previtellogenic oocytes are not resorbed and perhaps subsequently undergo vitellogenesis. The ovary in this highly opportunistic polychaete species may play a significant regulatory role in the control of reproduction by producing yolk precursors, regulating their uptake from the coelomic fluid via the activity of the follicle cells and by resorbing mature oocytes in response to stress.

Immunocytochemical and ultrastructural correlates of the pineal inhibition of prolactin cell activity in blind-anosmic female rats.

The effects of the pineal gland on the light microscopic-immunocytochemical and ultrastructural appearance of pituitary mammotrophs were studied in female rats eight weeks after prepubertal blinding and olfactory bulbectomy. Blinding and anosmia resulted in a marked decrease in the size of the pars distalis concomitant with a reduction in the apparent number and size of PRL cells as compared with intact animals. Ultrastructurally, these cells appeared much less active than those of intact rats. The small and angular-shaped mammotrophs of blind-anosmic rats characteristically exhibited scant arrays of rough endoplasmic reticulum, small Golgi complexes with few immature secretory granules, few mature secretory granules and rare exocytosis patterns. Pinealectomy tended to reverse the effects of blinding and anosmia on pars distalis size and PRL cell size, apparent number and ultrastructure. In fact, the mammotrophs of blind-anosmic-pinealectomized rats were quite similar in ultrastructural appearance to those of intact rats. From these data we conclude that the pineal causes mammotroph hypotrophy and hypoplasia in blind-anosmic female rats.

Ultrastructure of the male reproductive system and spermatophore formation in Labidocera aestiva (Crust.: Copepoda)

The male reproductive system of Labidocera aestiva produces a flask-shaped spermatophore connected to a chitin-like coupling apparatus. As immature spermatozoa leave the anterior region of the testis, they pass through the lumen of a long, sinuous duct composed of a ductus deferens and seminal vesicle. Ultrastructural examination of the ductus deferens reveals a highly glandular, columnar epithelium. The cells contain arrays of rough endoplasmic reticulum and abundant, well-developed Golgi complexes. This region produces and releases into the lumen, a flocculent substance and two granular secretions that constitute the seminal fluid. In its terminal part, the ductus deferens synthesizes another secretion that forms the spermatophore wall enclosing the spermatozoa and seminal fluid. Final synthesis of the spermatophore wall occurs within the thin-walled seminal vesicle, although this region functions primarily as a storage organ. Contiguous to the seminal vesicle is an elongate, highly glandular spermatophore sac. The chitin-like coupling apparatus, which functions to attach the spermatophore to the female, is formed in the anterior region of the sac by secretions from eight cell types. The posterior region of the sac stores the flask-shaped spermatophore and produces secretions that aid ejaculation of the entire spermatophore complex.

Fluoride stimulation of the rat parathyroid gland: an ultrastructural study.

The parathyroid glands of rats given 150 ppm fluoride in the drinking water for 10 weeks are evaluated ultrastructurally and compared to the parathyroid glands of untreated rats. As a result of fluoride ingestion, the majority of the parathyroid cells are dark chief cells, indicating that these cells are in the active stages of the secretory cycle. More significantly, in the fluoride-treated rats, the cytoplasmic organelles of the dark chief cells are even more developed that those seen in the dark chief cells of untreated rats. The dark cells contain an electron-dense cytoplasm with abundant lamellar arrays of rough endoplasmic reticulum, spiral aggregations of free ribosomes, multiple dilated Golgi complexes, and increased numbers of secretory granules. The cells are at a minimum dimension with maximum tortuosity of the plasma membranes; and, as a result, large intercellular spaces are often seen between contiguous cells. Based on these observations, it is suggested that, in the fluoride-treated rat, a type of secondary hyperparathyroidism develops resulting in an increase in the organelles involved in protein synthesis and secretion.