Cytoplasmic tubular structures in kidney biopsies in systemic lupus erythematosus.
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Arthritis, Rheumatoid↗
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Results for “Cytoplasmic Structures”
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Observations on intranuclear and cytoplasmic paracrystalline structures in differentiating oocytes of the ostracod, Cypridopsis vidua.
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Animals↗
Cytoplasmic crystalline structures in lymphoid cells of a human renal allograft.
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Adult↗
Lead poisoning: rapid formation of intranuclear inclusions.
A single dose of lead (0.05 milligram per gram of body weight) induced characteristic intranuclear inclusions in the epithelium of proximal tubules in rat kidney within 1 to 6 days. The development of the intranuclear inclusions is thus an acute manifestation of lead poisoning, not a delayed one, as has been thought hitherto. Cytoplasmic structures resembling the intranuclear inclusions and situated in the vicinity of endoplasmic reticulum were regularly found in cells bearing the pathognomonic intranuclear inclusions. The latter and the cytoplasmic structures may be derived from a common precursor, perhaps a soluble protein-lead complex.
Animals↗
Molecular structure of cytoplasmic dynein 2 and its distribution in neuronal and ciliated cells.
Cytoplasmic dynein is involved in a wide variety of cellular functions. In addition to the initially characterized form (MAP 1C/dynein 1), a second form of cytoplasmic dynein (dynein 2) has been identified and implicated in intraflagellar transport (IFT) in lower eukaryotes and in Golgi organization in vertebrates. In the current study, the primary structure of the full-length dynein 2 heavy chain (HC) was determined from cDNA sequence. The dynein 1 and dynein 2 sequences were similar within the motor region, and around the light intermediate chain (LIC)-binding site within the N-terminal stem region. The dynein 2 HC co-immunoprecipitated with LIC3, a homologue of dynein 1 LICs. Dynein 2 mRNA was abundant in the ependymal layer of the neural tube and in the olfactory epithelium. Antibodies to dynein 2 HC, LIC3 and a component of IFT particles strongly stained the ependymal layer lining the lateral ventricles. Both dynein 2 HC and LIC3 staining was also observed associated with connecting cilia in the retina and within primary cilia of non-neuronal cultured cells. These data support a specific role for dynein 2 in the generation and maintenance of cilia.
Animals↗
NMR-based modelling revealed an alpha helical structure for cytoplasmic domain of the alpha subunit of Fc epsilon RI, the high affinity IgE receptor.
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Amino Acid Sequence↗
Diffusion of a small molecule in the cytoplasm of mammalian cells.
Electron spin resonance was used to measure the diffusion of a small (Mr 170) spin label in the aqueous cytoplasm of mammalian cells. Translational and rotational motion were determined from the same spectra. Based on measurements made in model systems, it was hypothesized that calculations of the apparent viscosity from either rotational or translational motion would distinguish between the effects of cytoplasmic viscosity or cytoplasmic structure on diffusion. The diffusion coefficient calculated from spin label collision frequency, averaged 3.3 X 10(-6) cm2/sec in several cell lines. It was greater in growing cells and in cells treated with cytochalasin B than in quiescent cells. The viscosity of the cytoplasm calculated from the translational diffusion coefficient or the rotational correlation time was 2.0-3.0 centipoise (1 P = 0.1 Pa X sec), about 2-3 times that of the spin label in water. Therefore, over the dimensions measured by the technique, 50-100 A, solvent viscosity appears to be the major determinant of particle movement in cells under physiological conditions. However, when cells were subjected to hypertonic conditions, the translational motion decreased by 67%, while the rotational motion changed less than 20%. These data suggested that the decrease in cell volume under hypertonic conditions was accompanied by an increase in cytoplasmic barriers and a decrease in the spacing between existing components. In addition, a comparison of reported values for diffusion of a variety of molecules in water and in cells indicates that cytoplasmic structure plays an important role in the diffusion of proteins such as bovine serum albumin.
Animals↗
The primary structure of cytoplasmic initiator transfer ribonucleic acid from Torulopsis utilis.
Cytoplasmic initiator transfer ribonucleic acid (tRNAinit) was purified from bulk Torulopsis (Candida) utilis tRNA by a series of column chromatography procedures. Sequence analysis of the products of complete and partial digestion of this tRNA with ribonuclease A [EC 3.1.4.22] and ribonuclease T1 [EC 3.1.4.8] enabled us to determine the complete primary structure of the molecule. The chain length of this tRNA was 76, including 11 modified nucleotides. The structure of the tRNA was arranged into a cloverleaf model and compared with those of other initiator tRNA species. As in the cytoplasmic initiator tRNA's of most other eukaryotic cells, the sequence -A-U-C-G- is contained in this tRNA in place of the usual -T-psi-C-G (or A)- found in other tRNA's.
Base Sequence↗
An ultrastructural study of the liver in Indian childhood cirrhosis with particular reference to the structure of cytoplasmic hyaline.
Ultrastructural features of the liver in eight cases of Indian childhood cirrhosis, a fatal and elusive liver disease in India, have been described. Severe parenchymal damage, diffuse creeping fibrosis, and other light microscopic alterations, including the frequent presence of cytoplasmic hyaline, reported earlier are confirmed in the present study. The hyaline is predominantly comprised of tangled masses of fibrils and some electron-dense particles possibly derived from endoplasmic reticulum. The morphological features of this hyaline are identical to those of alcoholic hyaline described by Biava and Smuckler. Mitochondria do not seem to participate in the structural evolution of hyaline.
Bile↗
Virus-induced cytoplasmic membrane structures associated with Semliki Forest virus infection studied by the freeze-etching method.
Intracellular membrane structures associated with the Semliki Forest virus replication process were studied from freeze-etch replicas. Cleaved membrane structures inside the CPV I type vacuoles lacked the typical membrane particles present on most other fractured membranes. CPV II type vacuoles present in thin sections were obscured in the freeze-etch replicas by the cytoplasmic ground substance.
Animals↗
Cytoplasmic surface structure in postsynaptic membranes from electric tissue visualized by tannic-acid-mediated negative contrasting.
In this study, acetylcholine receptor-rich postsynaptic membranes from electric tissues of the electric rays Narcine brasiliensis and Torpedo californica are negatively contrasted for thin-section electron microscopy through the use of tannic acid. Both outer (extracellular) and inner (cytoplasmic) membrane surfaces are negatively contrasted, and can be studied together in transverse sections. The hydrophobic portion of the membrane appears as a thin (approximately 2 nm), strongly contrasted band. This band is the only image given by membrane regions which are devoid of acetylcholine receptor. In regions of high receptor density, however, both surfaces of the membrane are seen to bear or be associated with material which extends approximately 6.5 nm beyond the center of the bilayer. The material on the outer surface can be identified with the well-known extracellular portion of the receptor molecule. A major portion of the inner surface image is eliminated by extraction of the membranes at pH 11 to remove peripheral membrane proteins, principally the 43,000 Mr (43K) protein. The images thus suggest a cytoplasmic localization of the 43K protein, with its distribution being coextensive with that of the receptor. They also suggest that the 43K protein extends farther from the cytoplasmic surface than does the receptor.
Animals↗
Nucleotide sequence and structure of cytoplasmic 5S RNA and 5.8S RNA of Chlamydomonas reinhardii.
Three small RNAs of the cytoplasmic 8OS ribosomes of the green unicellular alga Chlamydomonas reinhardii have been sequenced. They include two species of ribosomal 5S RNA, a major and a minor one of 122 and 121 nucleotides respectively, which differ from each other by 17 bases, and also the ribosomal 5.8S RNA of 156 nucleotides. Novel structural features can be recognized in the 5S RNAs of C. reinhardii by a comparison with published 5S RNA sequences. In addition the secondary structure of these small RNA molecules has been examined using a newly developed method based on differential nuclease susceptibility.
Base Sequence↗
Effects of p-chlorophenylalanine, amiflamine and melatonin treatment on the ultrastructure of pinealocytes in Sus scrofa.
The effects of p-chlorophenylalanine (pCPA), amiflamine [Fla 336(+)] as well as melatonin (MEL) treatments on the ultrastructure of pinealocytes in immature female pigs were investigated. Treatment of pCPA-tryptophan hydroxylase inhibitor resulted in the presence of numerous membrane-bound bodies type 2, with long, narrow cisterns of endoplasmic reticulum and a large Golgi apparatus. Fla 336(+) selective MAO-A inhibitor influenced the system of dense bodies, mitochondria and lysosomes (increasing their relative volume). Injections of melatonin resulted in the appearance of numerous homogeneous, round, regular shaped structures surrounded by membrane cytoplasmic structures ('granules'). The results indicate that a peculiar system of cytoplasmic dense bodies may be involved in indoleamine secretion in the pig pinealocyte.
Animals↗
Glomerular cytoplasmic tubular structures in renal biopsies of patients with systemic lupus erythematosus and other diseases.
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Adult↗
Acrosome formation during spermiogenesis in Notonecta glauca L. (Heteroptera).
The giant spermatozoon of Notonecta glauca has a 1 mm long acrosome. It has the shape of a stiff needle with round cross section and contains several different components. Morphogenesis of this simple form proceeds by very complex changes of both the internal structure and the outer shape. Surrounded by a great number of individual dictyosomes the acrosome is attached to the anterior nuclear pole where it grows to a sphere measuring about 20 microns in diameter. In its interior differentiations consisting of several components become visible which develop independently and may be characterized as basal and lateral complexes. At the end of the growing phase these two complexes come in contact with each other. After the dictyosomes have detached from the acrosome, the cell membrane surrounds the acrosome very closely so that cytoplasmic structures temporarily disappear completely from the narrow space in between. The tip of the acrosome grows out of the sphere as a slender lateral process which becomes increasingly spiralized. It shows a deep lateral groove, its contents consist of components of the basal complex. Parts of the lateral complex form a baso-lateral protuberance. Between these two structures a narrow channel extends from the subacrosomal space to the base of the lateral process. During elongation the acrosome attains spindle shape, the lateral process gradually becoming its anterior part. The distance between acrosome and cell membrane broadens again and cytoplasmic structures reappear among them about 1000 microtubules which are not surrounded by a sleeve membrane. In the posterior part cell membrane and acrosomal membrane are connected by two lines of weld spots where acrosomal membrane is eliminated as small vesicles. In the anterior part the groove becomes deeper. One leg of its initially U-shaped cross section becomes longer and is wrapped around the shorter one. The two legs subsequently fuse with the consequence that membrane and cytoplasmic components of the former groove become secondarily incorporated into the acrosome. The subacrosomal channel obliterates and the cross section of the acrosome showing acute angles in later stages finally gets round. Anterior and posterior part of the acrosome can be differentiated due to structural details even in the mature sperm.
Acrosome↗
The long-term cellular response to taxol in peripheral nerve: Schwann cell and endoneurial cell changes.
Taxol, an agent known to stabilize and increase the assembly of microtubules, causes long-lasting nerve damage when injected into peripheral nerve. In the present study, the cellular response to taxol in rat sciatic nerve was studied for up to 6 months after a single injection. The initial response of Schwann cells to taxol at the lesion site involved the accumulation of cytoplasmic microtubules which persisted up to 4 months after injection. Some novel microtubule-related cytoplasmic structures were also noted; these included microtubule-lined cytoplasmic crypts and channels. Despite these structural abnormalities, Schwann cells were able to produce myelin sheaths around taxol-induced axonal bulbs. This myelination showed some anomalies up to 4 months consisting of the widening of myelin lamellae, variability in sheath thickness, paranodal myelin infoldings and myelin protrusions. With time the diameter of the axonal bulbs decreased and, concomitant with this, more normal-appearing remyelination occurred. By 5 months, the previously noted myelin abnormalities were rare. By 6 months only a few naked axonal segments occurred at the lesion site. In endoneurial fibroblasts and macrophages cytoplasmic lamellar microtubule formations were frequent at 10 weeks. Needle-like cytoplasmic structures appeared within endoneurial cells at the site of the lesion after 10 weeks. By 3 months these inclusions were numerous and were often surrounded by extended cytoplasmic processes. The needles were up to 50 microns long and 3 microns wide and probably represented cholesterol. By 4 months the number of cytoplasmic needles decreased and at 5 months onwards none was observed. The present findings confirm and extend previous findings that taxol has a long-lasting effect upon both Schwann cells and endoneurial cells and that this is related to abnormal tubulin synthesis.
Alkaloids↗
Colchicine antagonizes the activity of human smooth muscle cells cultivated from arteriosclerotic lesions after atherectomy.
AIM: Proliferative, migratory, and secretory activities of vascular smooth muscle cells are functional determinants of human atherosclerotic plaque and restenosis formation. The present study was designed to examine the effects of interfering with these processes using drugs. MATERIALS AND METHODS: For in-vitro studies of smooth muscle cell activity, arterial smooth muscle cells were cultivated from human plaque tissue excised from 22 coronary and peripheral lesions and treated with the antitubulin colchicine. Smooth muscle cell migratory activity was analyzed by a standardized semi-automatic video system. Transmission electron microscopy was used to examine cytoplasmic structures. RESULTS: Colchicine caused a concentration-dependent decrease in smooth muscle cell proliferative activity at a half-maximal inhibitory concentration (IC50) of 5 nmol/l. Smooth muscle cell migratory activity was reduced by colchicine in a concentration-dependent manner (IC50, 3 nmol/l). Concordantly, transmission electron microscopy revealed severe disorganization of cytoplasmic structures, especially of organelles, indicating metabolic activation. CONCLUSIONS: In-vitro studies with human smooth muscle cells from arteriosclerotic lesions suggest that the antitubulin principle may be useful in producing anti-arteriosclerotic effects, since a pronounced antagonization of smooth muscle cell proliferative, migratory, and secretory processes, indirectly inferred from ultrastructural analysis, was demonstrated with low concentrations of colchicine.
Actin Cytoskeleton↗
[Cytoplasmic cisterns structurally linked with the plasmalemma in the hepatocytes of mice of different lines].
Structures of the granular endoplasmic reticulum and narrow canals formed by smooth membranes were found in the cell membrane of male mice belonging to strains CBA, C57BL and L-NZB/BLN. The canals were seen connected with plasma membranes. Under the conditions of CC1(4) poisoning of CBA and C57BL mice, these canals were transformed to gigantic cytoplasmic vacuoles. Their cavities were communicated with the extracellular space. It still remains unclear if the membranes of these canals belong to the cytoplasmic membrane or to the endoplasmic reticulum.
Animals↗