Electron-opaque Granules Research Articles

Stimulation of crop sac and pituitary lactotrophs after intraventricular administration of dermorphin in pigeons

The effects of dermorphin, a new potent opioid peptide, on structural and ultrastructural changes in the crop sac and in pituitary lactotrophs were assessed in pigeons ( Columba livia). A single administration of dermorphin into the third cerebral ventricle (1 μg) and the same dose repeated for 3 consecutive days both produced maximal crop sac stimulation, as documented by the presence of milk-like material as well as by scanning and transmission electron microscopy of crop sac mucosa. In addition, marked stimulatory effects were also observed in pituitary lactotrophs, as shown by stimulation of Golgi apparatus, enlargement of rough endoplasmic reticulum, increase in mitochondria size, and the presence of lysosomes and electron-opaque granules. The stimulatory effects of dermorphin on the crop sac and lactotrophs were completely prevented by naloxone, an antagonist at opiate receptors. Since dermorphin is a natural constituent of the avian brain, it has been suggested that this peptide may represent the still-obscure hypothalamic prolactin stimulatory factor.

Occurrence of intramitochondrial Ca2+ granules in a hypertrophied heart exposed to adriamycin.

Left ventricular hypertrophy was produced in rabbits by narrowing the abdominal aorta in the subdiaphragmatic region. Six weeks after the surgery, sham control as well as hypertrophied animals were treated with adriamycin. Myocardial cell damage resulting from a total cumulative dose of 5 mg/kg of adriamycin was seen only in hypertrophied hearts. Alterations in muscle cells of these hearts included prominent "contraction bands" and perinuclear edema. Mitochondria were characterized by swelling and accumulation of electron-opaque granules. Energy-dispersive x-ray analysis of the mitochondria revealed the presence of calcium in these granules. The study confirms that the hypertrophied heart is more vulnerable to adriamycin-induced cell damage and this may be due to an increased susceptibility of these hearts to the occurrence of Ca2+ overload in the cell.

Tracheobronchial epithelium of the sheep: II. Ultrastructural and morphometric analysis of the epithelial secretory cell types.

In a light microscopic study we have described the morphology and distribution of six distinct, granule-containing cells in the tracheobronchial epithelium of sheep lung. We designed the present study to determine qualitatively and quantitatively whether these six cell types differ in ultrastructural morphology. Cell height varied from 30.6 micron for mucous cell M1 to 9.6 micron for Clara cells. Cell width varied from 21.2 micron for M1 to 9.3 micron for Clara cells. Nuclear dimensions ranged from 7.5 micron in M3 to 4.0 micron in M1 and M2. Mucous cell M1 had electron-dense granules (1.5 micron in diameter); M2, electron-lucent granules (1.6 micron); M3, nucleated electron-lucent granules (0.51 micron); M4, cored granules (1.1 micron); serous (SC) and Clara cells (CC), electron-opaque granules (0.58 micron and 0.37 micron). The volume fraction of the cell occupied by granules was 63% in M1 and M2, M4 39%, SC 23%, CC 5%, and M3 4.5%. Smooth endoplasmic reticulum was observed only in M3 (33.8%) and CC (49%). Granular endoplasmic reticulum (GER) was most abundant in SC (21%) and least plentiful in M4 (2.2%). We conclude that mucous cells M3 and M4 and serous and Clara cells differ from each other and from M1 and M2 cells. Mucous cells M1 and M2 differ from each other only in amount of GER and secretory granule appearance.

Nuclear and cytoplasmic inclusion bodies in pinealocytes of the cotton rat, Sigmodon bispidus: an electron microscopic study.

Electron microscopic observations on pinealocytes of cotton rats (Sigmodon bispidus) killed in October revealed the presence of cytoplasmic inclusion bodies (CIBs) and two kinds of nuclear inclusions--coiled bodies and granular inclusion bodies. These inclusions were usually not bounded by a membrane. CIBs showed round or irregular profiles and consisted of granular and filamentous materials of moderate electron opacity intermingled with electron-lucent areas. Nuclear granular inclusions appeared as homogeneous or heterogeneous granules of variable electron opacity, which usually exhibited round profiles of variable diameters and consisted of granular and filamentous elements. Electron-opaque granules were observed in perinuclear spaces, dilated cisternae of rough endoplasmic reticulum, as well as in the central portion of CIBs. In CIBs containing granules, the peripheral region was composed of the moderately electron-opaque substance seen in usual CIBs, while the central core was occupied by a granular and filamentous substance and an intervening electron-lucent matrix. Since an electron-opaque granular substance in nuclei, perinuclear spaces, cisternae of rough endoplasmic reticulum, and the central portion of CIBs may occur concomitantly, the granules seen in these sites may be related. Coiled bodies were round in profile and were composed of electron-opaque strands consisting of granular and filamentous elements and intervening material of low electron opacity. This structure, frequently located in close proximity to the nuclear granular inclusions, may play a role in the formation of the intranuclear granules in cotton rat pinealocytes.

Demonstration of mitochondrial mineral deposits in osteoblasts after anhydrous fixation and processing.

The fine structure of early developing bone was examined using a modification of a new non-aqueous processing method in which anhydrous glutaraldehyde dissolved in dimethylsulphoxide (GLUT-DMSO) is used as a fixative. Preliminary results show that the basic morphological features of the cellular and extracellular compartments of developing bone were preserved. The cytoplasm of osteoblasts revealed numerous well-preserved mitochondria and other membranous organelles. Inside the mitochondria there were large and conspicuous electron-opaque granules of mineral which were more prominent and numerous than in specimens prepared by conventional aqueous procedures. The collagenous matrix also revealed electron-opaque deposits of mineral. These results support the evidence for the existence of mitochondrial calcium phosphate in osteoblasts in the form of granules.

Immunocytochemical identification of cells containing insulin, glucagon, somatostatin, and pancreatic polypeptide in the islets of Langerhans of the guinea pig pancreas with light and electron microscopy.

Cell types containing insulin, glucagon, somatostatin, and pancreatic polypeptide were identified in guinea pig islets with light and electron microscopic immunoperoxidase staining. Cells containing immunostainable insulin (B cells) are located throughout the islets, including the islet periphery, and contain irregularly shaped granules (350-550 nm). Granule contents are of variable opacity and are often fragmented but not crystalloid. Cells containing immunoreactive glucagon (A cells) are found in the interior of islets and contain numerous spheroid electron-opaque granules (250-350 nm). Cells containing immunoreactive somatostatin (D cells) have elongate, axonlike processes that end adjacent to islet capillaries. D cells, which are very numerous and distributed uniformly throughout the islet parenchyma, contain small spheroid granules (150-25 nm) of pale electron opacity. Cells with immunoreactive pancreatic polypeptide (F cells) are rare in islets but numerous among the exocrine parenchyma. F cells contain pale spheroid granules (100-200 nm). Morphological criteria are reliable indicators for A cells and B cells, but D cells and F cells require immunostaining for positive identification.

Ciliary specializations in mating cells of the ciliate Euplotes crassus.

In the ciliate Euplotes crassus, mixed cells of different compatible mating types pass through an induction period before agglutinating with each other by means of cilia in the mating reaction. We examined the ciliary membranes of cells involved in the mating reaction by the freeze-fracture technique and detected at least 5 distinct types of specialization, each indicated by a special congregation of intramembrane particles. Near to the necklace, at the ciliary base, we observed a set of several parallel transverse rows of 10-15 nm particles; a longitudinal row of 12 nm particles appeared more distally from the necklace, preferentially in replicas of intermediate regions of the ciliary shaft. These 3 specializations were common to both mating and vegetative cells. The other 2 appeared as more dynamic specializations found exclusively at least in their patterned organization, in the ciliary membranes of mating cells. Taking on the aspects of rosette-like arrays and patches, respectively, the former were positioned regularly on ciliary membrane bulges (containing an electron-opaque granule) and consisted of 8-9 nm particles; the latter had an elliptic shape and contained up to 50 closely packed 9-10 nm particles.

Calcium accumulation in vacuoles of Physarum polycephalum following starvation.

The plasmodium of Physarum polycephalum contained 15.3 mmol Ca/kg fresh weight of sample, 11.8 mmol Mg/kg, 24.5 mmol K/kg and 1.4 mmol Na/kg. When the plasmodium was starved of food, the Ca content increased gradually up to 71.9 mmol/kg during 5 days of starvation. The concentration of other elements changed only slightly. The endoplasm contained 23.0 mmol Ca/kg, 12.6 mmol Mg/kg, 26.6 mmol K/kg and 1.7 mmol Na/kg, but these contents changed only slightly during starvation. The Ca, Mg, K and Na contents of the slime and the soluble fraction were also determined. In order to clarify where the accumulated Ca was localized, Ca in the plasmodium was precipitated with potassium pyroantimonate and examined by electron microscopy. In the starved plasmodium, the vacuoles which contained the electron-opaque precipitates and were located in the ectoplasm increased in number, compared with the unstarved plasmodium. At the same time the large electron-opaque granules in the extracellular slime increased in number. The electron-opaque precipitates were identified as Ca pyroantimonate by its susceptibility to removal by chelation with ethyleneglycol bis (beta-aminoethyl ether) N, N, N', N'-tetraacetic acid (EGTA) and X-ray microprobe analysis.

Licht- und elektronenmikroskopische Untersuchung des Corpus cardiacum der Eintagsfliege Ephemera danica Müll. (Ephemeroptera: Ephemeridae) während der Metamorphose*

Kaiser, H. 1980. Licht- und elektronenmikroskopische Untersuchung des Corpus cardiacum des Eintagsfliege Ephemera danica Mull. (Ephemeroptera: Ephemeridae) wahrend der Metamorphose. [Light- and electron microscopic investigation on the corpus cardiacum in the mayfly Ephemera danica Mull. (Ephemeroptera: Ephemeridae) during metamorphosis.] (Zoologisches Institut der Universitat Basel, Schweiz.) — Acta zool. (Stockh.) 61(2): 93–103. The corpus cardiacum (cc) of Ephemera danica is an unpaired organ in the dorsal wall of the aorta. During the last four instars there has been no significant change in the volume of the cc of the males. In the females, however, the cc enlarges in the final nymphal instar due to a thickening of the organ. Owing to a shortening prior to the subimaginal moult the volume has diminished in the subimagines and imagines. In the electron microscope different types of axons and secretory granules could be observed. The type a axons contain electron opaque granules with a mean diameter of 125 nm. The granules in the axons of type b are smaller (mean diameter 85 nm) and are more or less electron opaque, and the type c axons are filled with less electron opaque secretory droplets with mean diameters of 170 nm. In the fourth type of axons (d) the granules are approximately the same size as those of the type a but are more irregular in shape. In addition to the different axons two cell types—interstitial and secretory cells—are described, and the probable mechanism of the release of neurosecretory material is discussed. During metamorphosis only minor changes were apparent at the ultrastructural level.

The cytologic composition of primate laryngeal chemosensory corpuscles

The present study defines the cellular composition of chemosensory corpuscles (taste buds) present in the mucosa overlying the arytenoid cartilages of the larynx in serial sections studied by electron microscopy. Three cell types can be defined in such chemosensory corpuscles. Basal cells are relatively undifferentiated in terms of cytologic characteristics and have been identified presumptively as the stem cells for differentiation of the other two cell types. Sustentacular or supporting cells are characterized by the presence of apical electron-opaque granules that apparently are extruded into the lumen of the pore, and are, thus, the source of the electron-opaque extracellular material present between the microvilli protruding from the apex of the cells into the chemosensory corpuscle pore. The chemosensory cells are characterized by the presence of synaptic specializations with appended nerve fibers at the base of the cell, the presence of specific cytoplasmic secretory granules, as well as numerous clusters of typical synaptic vesicles, and apical microvilli that extend into the pore of the corpuscle. Other cell profiles encountered in chemosensory corpuscles are cells in various stages of degeneration or transition, to one of the other cell types, from undifferentiated basal cells. Two types of synaptic specializations have been identified as being associated with chemosensory cells. The first is characterized by an increased electron-opacity of the respective plasma membranes of nerve fiber and chemosensory cell. In this situation numerous synaptic vesicles usually are present in the cytoplasm of the chemosensory cell subjacent to the membrane densities. A second type of synaptic association is characterized by the presence of subsurface cisterns of agranular endoplasmic reticulum in the cytoplasm of the chemosensory cell, and numerous synaptic vesicles often are present in the axoplasm of the subjacent neurite, suggesting a reciprocal synapse. These findings are interpreted to indicate that only one cell type is specialized for transducing chemical signals into neural activity and that this cell is modulated by activity of the nervous system.

喉頭披裂部カルチノイドの一生検例

A 74-year-old housewife consulted with dyspnea of almost 1 year duration. She had neither dyspnea, hemoptoe, nor hoarsness. Her physical examinations including X ray shadows revealed no abnormality. A nodular tumor was detected to be extending from the left arytenoid in laryngoscopy. There were no palpable lymph nodes in the cervical regions, and neither tumor nor ulcer in the esophageal mucosa. A biopsy specimen revealed carcinoid tumor in the arytenoid. The patient did not show so-called carcinoid syndromes. The excised tumor,0.6 x 0.6 X 0.3 cm, was gray white and somewhat nodular. Microscopically, the tumor cells were located within the submucosa beneath the histologically normal, surface-covering squamous epithelium. They were fairly small, uniform-sized cells with scanty cytoplasm, and arranged in nodular and/or acinar structures. Few mitotic figures could be seen. In the cytoplasms of tumor cells, argentaffin reaction was negative and argyrophilic stain was positive. Ultrastructurally, the nuclei exhibited irregular shapes with prominent nucleoli but no obvious chromatin condensation at their margins. Many of the uniform-sized (200-300 nm in diameter), electron-opaque granules with clear halo and limiting membrane, which were similar to the neurosecretory granules in the carcinoid tumor or the oat cell carcinoma of the lung, were found in the cytoplasms. Carcinoid of the arytenoid has never been described in the literatures. Only 1 case of laryngeal carcinoid,14 cases of tracheal carcinoid and 2 cases of esopahgeal carcinoid have been reported. Oat call carcinoma has been described in 6 tracheas and 7 esophagi.

The aspect of ultrastructural changes of the osteoblasts and surface areas of alveolar bone appearing in experimental tooth movement: Aya o HirashitaBull. Tokyo Med. Dent. Univ. 23:245–260, 1976

Molars of mature Wistar rats were moved experimentally by orthodontic elastic for four days. Then, the aspects of ultrastructural changes of the osteoblasts and structure of the alveolar bone surface which appeared in experimental tooth movement were studied. The following results were obtained. 1) These osteoblasts are classified into three groups according to their position. 2) The most active response to the orthodontic force is exhibited by the second group of cells with the ability of rapid production of abundant acid polysaccharide; i) Abundant rough surfaced endoplasmic reticulum with markedly dilated cisternae. ii) Well developed Golgi apparatus and electron opaque granules with a limiting membrane are found in the cytoplasm. Large granules are frequently seen to be secreted out of the cell. iii) The mitochondria are of large size and round shape with well developed cristae. 3) The surface of the new alveolar bone is covered with a belt-shaped structure consisting of small dense spherical-shaped structures. 4) Osteoclasts are rarely seen, but the original function of the cells appears to be almost inactive.

The development of nuclear vacuoles during meiosis in plants

Vacuoles formed by the invagination of the inner membrane of the nuclear envelope have been observed during meiotic prophase in a wide range of plants. In the angiosperm Lycopersicon their formation was found to coincide with the completion of synaptonemal complex formation, and this timing is analogous to that observed during this stage in the silkworm Bombyx. The implications of this activity in relation to the process of chromosome movement are discussed. In the gymnosperm Pinus, the heterosporous fern Marsilea and homosporous ferns Pteridium and Dryopteris the formation of nuclear vacuoles begins much earlier, coinciding with the condensation of chromatin during leptotene. They enlarge and become more elaborate as meiosis proceeds, and may eventually become detached from the nuclear envelope. It is therefore thought unlikely that theyfulfil functions connected with chromosome movement in the manner proposed for the silkworm and the tomato. During diplotene/diakinesis they contain electron-opaque granules and fibrils, and the possible origin and significance of this material is discussed.

Licht- und elektronenmikroskopische Untersuchung von neurosekretorischen Zellen im Gehirn der EintagsfliegeEphemera danicaMüll. (Ephemeroptera: Ephemeridae)

In the brains of the males the amount of stained secretory material was nearly constant during the last four instars. In the females a decrease in this neurosecretory product in the last nymphal and subimaginal stage could be observed, followed by an increase in the imagines. In the final nymphal stage four types of neurosecretory cells (nsc) were found in the medial protocerebral cell group, showing differences in shape, size, and the contents of the cytoplasm, especially of the secretory granules. In addition to the medial nsc, some cells in the frontal part of the brain and in the deutocerebrum are described. They contain electron-opaque granules and probably have a neurosecretory function. The secretory product of the medial nsc is transported along the axons of the nervus corporis cardiaci 1 (ncc1), an unpaired nerve tract on the ventral side of the brain. Leaving the brain the ncc1 immediately enters the corpus cardiacum. Connections between secretory granules and neurotubuli point to an important role for the neurotubuli in the transport of secretory material.

Ultrastructure of the formation of γ particles during zoosporogenesis in Allomyces macrogynus and Catenaria anguillulae

The sequence of intracellular transitions leading to the formation of γ particles during zoosporogenesis was examined by electron microscopy of synchronous cultures of Allomyces macrogynus and semisynchronous cultures of Catenaria anguillulae . In Allomyces the first identifiable progenitors of the γ matrix are 60-nm-diameter electron-opaque granules found within cisternae of rough ER. These particles appear during the first 30 minutes after the induction of sporogenesis. By the completion of papilla formation these “subunits” increase in number and size to form spherical structures ca. 133 nm in diameter. At the beginning of nuclear cap formation the 133-nm-diameter electron-opaque granules fuse to form larger spheres averaging 216 nm in diameter. These structures occur singly and in groups which fill the smooth-surface cisternae containing them. Toward the end of nuclear cap formation the granules fuse to form the 500-nm-diameter γ body. In Catenaria the first progenitors of γ particles are 45-nm-diameter electron-opaque granules with transparent centers that appear within swollen cisternae of tubular smooth ER. These granules form larger aggregates which fuse after cleavage to form the fully differentiated γ matrix. The γ particles of Catenaria are ca. 250 nm in diameter, which is smaller than the ca. 500-nm-diameter γ particles of Allomyces macrogynus and Blastocladiella emersonii .

Post-meiotic nucleo-cytoplasmic interaction in Cosmos bipinnatus

An interaction involving the nuclear envelope and spherical double-membrane bound inclusions takes place in the cytoplasm of post-meiotic male microspores of Cosmos (tribe Heliantheae, sub-tribe Coreopsidinae). The identity of the spherical inclusions has yet to be fully established, but they closely resemble profiles elsewhere in the cytoplasm, themselves presumably derived from the mitochondrial population of the premeiotic pollen mother cells. Both the cytoplasmic and nucleaar-associated inclusions regularly contain a central 'vesicle', formed by an ingagination of their bounding membranes. The interaction, which occurs immediately prior to the deposition of the primexine of the pollen wall, involves the adhesion of the inclusions to the nuclear surface. Experiments with osmotically disrupted cells reveal that the inclusions are firmly bound to the envelope and, at the points of contact, electron opaque granules are regularly present. Frequently elements of the chromatin may be observed in juxtapostion to these points of contact, but on the inner face of the envelope. The interaction in Cosmos is proposed to constitute part of the process by which the cytoplasm and its content are realigned to the new "gametophylic" style of growth.

Endoneurial mast cells in peripheral nerves of the armadillo dermis.

Electron microscopy of the dermis of the 9-banded armadillo, Dasypus novemcinctus, reveals an intimate relationship of mast cells to peripheral nerves. Mast cells are routinely found in the dermis in close proximity to nerves, and mast cells are also present within the perineurial cell sheath in the endoneurial space proper. These cells contain electron opaque granules and exhibit numerous surface folds as is characteristic of other species. The degranulation of the mast cells by injection of 0.5% aqueous trypan blue reveals sequential exocytosis of granules, similar to that described for the rat. Degranulation occurs in most dermal and endoneurial mast cells following a single intradermal injection of trypan blue. A small number of mast cells partially degranulate and a few exhibit no degranulation, suggesting a heterogeneous population. It is also noted that mitochondrial morphology differs in degranulating cells, in that they become swollen and vacuolated. The results of this study are discussed in light of previous results reported for other species, mainly at the light microscope level.

Vascular smooth muscle mitochondria: Magnesium content and transport

Endogenous magnesium content and magnesium transport of isolated bovine vascular smooth muscle mitochondria were studied. Mitochondria isolated from atherosclerotic bovine arteries contained two to three times as much magnesium (178 nmol/mg of mitochondrial protein) as those isolated from normal arteries (67 nmol/mg of mitochondrial protein). Electron-opaque granules were visible in the unstained unfixed mitochondria and could be shown with electron probe analysis to consist of magnesium, calcium, and phosphorus. At concentrations of external Mg 2+ from 0 to 6 m m, the vascular smooth muscle mitochondria exhibited respiratory substrate-supported release of Mg 2+ as studied with metallochromic indicator, eriochrome blue, using dual-wavelength spectrophotometry. The maximal velocity of energized release (3 nmol of Mg 2+/s/mg of mitochondrial protein) was observed at 4 m m external Mg 2+ and the half-maximal transport occurred at 0.5 m m.

Ultrastructural changes induced by ACTH in normal adrenocortical cells in culture.

The effects of ACTH, its o-nitrophenyl sulfenyl derivative (NPS-ACTH) and dibutyryl cyclic AMP (dbc AMP) on the ultrastructural morphology of adrenocortical cells of adult rats in monolayer culture have been investigated. NPS-ACTH, which has previously been shown to stimulate steroidogenesis but not cAMP synthesis in adrenal cells, induced the same characteristic transformation of mitochondrial architecture as produced by ACTH or high concentrations of dbcAMP. All three agents caused the disappearance of electron-opaque granules present in the mitochondria of unstimulated cells. It was found that these granules could be extracted with EGTA (ethylene glycol-bis(beta-aminoethyl ether) N,N,N',N'-tetraacetate). These results are discussed in the light of the known importance of calcium ions in the actions of ACTH.

Silicon-containing granules of rat liver, kidney and spleen mitochondria. Electron probe X-ray microanalysis.

Isolated rat liver mitochondria containing granule aggregates (25-75 nm in diameter) and small (5-10 nm) electron opaque granules were examined by electron probe X-ray microanalysis. The granule aggregates gave an intense Si signal, while the small granules gave both Si and P signals. Isolated mitochondria of rat liver, spleen and kidney, subjected to detergent solubilization and differential centrifugation, produced two granule fractions: (1) a 10,000 g fraction consisting predominantly of granule aggregates (25--75 nm) composed of smaller granules (5--10 nm in diameter), and (2) a 10,000--30,000 g fraction of non-aggregated small granules (5-10 nm). Thin sections of isolated granule aggregates gave Si X-ray signals similar to those obtained from in situ granules. In addition S, Cl, Mg, Cr and Fe X-ray signals were observed. Cr occurred only in the large kidney granules, while Fe occurred in both fractions of the spleen and kidney granules. The presence of Si in the granules was confirmed by chemical analysis of the isolated granules and in vivo radiolabeling of the granules with 31Si and 68Ge. Contamination within the electron microscope was eliminated by a liquid nitrogen anticontamination device.