Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0027960 (mole)
 21,279 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have recently shown that inositol 1,4,5-trisphosphate (IP3) releases Ca2+ from the endoplasmic reticulum of pancreatic acinar cells and suggested that IP3 may function as a second messenger of hormonal receptors to mobilize Ca2+ from intracellular stores (Streb et al, 1983, Streb et al, 1984). In rat kidney cortical tubules and microdissected mouse proximal tubules, an increased turnover of polyphosphoinositide metabolism following hormonal stimulation with angiotensin II-amide and phenylephrine has been reported (Wirthensohn et al, 1984; Wirthensohn et al, 1985). This suggests that IP3, one of their hydrolysis products, increases during hormonal stimulation. We therefore investigated the effect of angiotensin II-amide and IP3 on intracellular Ca2 stores in saponin-treated cells and homogenate from rat kidney cortex. Saponin-treated isolated cortical kidney cells or homogenate was incubated in a high K+ buffer in the presence of MgATP and respiratory substrates. Ca2+ uptake was determined by measuring the free Ca2+ concentration of the surrounding medium with a Ca2+ specific macroelectrode. Addition of cells or homogenate to the incubation medium resulted in a decrease of the medium free Ca2+ concentration until a steady-state concentration of 5.7 +/- 0.2 X 10(-7) mole/l was obtained. In the presence of mitochondrial inhibitors Ca2+ uptake rate was reduced, whereas the steady-state concentration was unchanged. In contrast, in the presence of the CA2+-ATPase inhibitor vanadate mitochondrial uptake proceeded at the same rate as the control, but the steady-state concentration was higher (6.9 +/- 0.2 X 10(-7) mole/l).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Inositol 1,4,5-trisphosphate releases Ca2+ from a nonmitochondrial store site in permeabilized rat cortical kidney cells. 348 13

To characterize the biological property unique to melanocytes and to utilize this property to establish laboratory diagnostic tools for malignant melanoma, monoclonal antibody (MoAb) human melanosome-associated antigen-1 (HMSA-1), a mouse monoclonal antibody, was developed against purified melanosomal fractions of human melanoma. MoAb HMSA-1 belongs to an IgG1 (kappa) subclass. Fractionation of cell organelles combined with enzyme linked immunosorbent assay analysis indicated that the antigen(s) reactive with MoAb HMSA-1 is localized in melanosome and endoplasmic reticulum fractions and that it is related to melanosomal protein and its precursor forms. The localization of the antigen in the melanosome and endoplasmic reticulum was also confirmed by immunoelectron microscopy. Characteristically, MoAb HMSA-1 reacted with formalin-fixed and paraffin-processed tissues of melanocytic nevi and malignant melanoma, including amelanotic lesions. It did not react with normal melanocytes, normal tissues and organs from fetuses and adults, or most non-melanocytic tumors. Thus MoAb HMSA-1 identifies the differentiation antigen for the melanosome-associated property in neoplastic melanocytes and is a useful adjunct for immunohistological diagnosis of melanocytic lesions on routine paraffin sections.
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PMID:Development and characterization of a mouse monoclonal antibody, MoAb HMSA-1, against a melanosomal fraction of human malignant melanoma. 351 87

Antimelanosome-associated monoclonal antibody has recognized the common antigenic determinant of melanosomes and cell surface of pigment cells, and it is suggested that melanosomes play a significant role as an antigen in progressive depigmentary disorders, in which melanocytes are selectively altered and disappear presumably by auto-antibodies in vivo. Mouse myeloma cells were fused with spleen cells from BALB/c mice immunized with a melanosomal fraction separated from human melanotic melanoma cells (Mm-1-JCK). The monoclonal antibody (MoAb) A4F11 has been found to react with premelanosomes, melanosomes, and probably with Golgi-associated endoplasmic reticulum lysosomes, but not with mitochondria, nuclei, and cytosol from human melanoma cells, by immunoelectron microscopy using the saponin permeation method, which was carried out together with indirect radioimmunoassay and quantitative absorption assay. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting using melanosome preparations have revealed the antigen(s) reactive with the MoAb A4F11 in 3 bands corresponding to Mr 50,000, 18,000, and 17,000. Cell binding assay has shown the reactivity of the MoAb A4F11 with the cell surface of human normal melanocytes and melanoma cells, but not with other mammalian melanoma cells or with human nonpigment cells examined. Indirect immunofluorescence on cultured cells and frozen sections has revealed distinct granular reactivity not only with human melanotic melanoma, but also with junctional and intradermal nevi, cultured malignant blue nevus cells, as well as normal melanocytes. The above evidence has indicated the presence of an antigenic determinant common to the intracellular melanogenic compartments and to the cell surface of human pigment cells, regardless of their oncogenic differentiation status.
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PMID:Melanosomal antigenic expression on the cell surface and intracellular subunits within melanogenic compartments of pigment cells: analysis by antimelanosome-associated monoclonal antibody. 352 55

The rate of transfer of spin-labeled phospholipid from donor vesicles of sonicated 1-acyl-2-(10-doxylstearoyl)-sn-glycero-3-phosphocholine to other vesicle was determined as a function of content of cytochrome P-450 and the phosphatidylcholine/phosphatidylethanolamine ratio in the acceptor vesicles. The transfer rate was measured as an increase in intensity that resulted from a decrease in the line width in the EPR spectrum of the spin-labeled phospholipids as they was transferred to the nonspin-labeled acceptor vesicles. A lower transfer rate was observed for acceptor vesicles of pure egg phosphatidylcholine vesicles than for vesicles for a mixture of phosphatidylcholine and phosphatidylethanolamine. The presence of cytochrome P-450 in the acceptor vesicles further increased the transfer rate. Those alterations in the mole ratios of the protein and the two phospholipids that made the bilayer of the reconstituted vesicles more like the membrane of the endoplasmic reticulum resulted in an increase in phospholipid-transfer rate. The mole ratios of components that produce high phospholipid-transfer rates were similar to those that in an earlier study produced a 31P-NMR spectrum characteristic of a nonbilayer phase. These findings suggest that, in the membrane of the endoplasmic reticulum, phospholipid exchange may be an important element in function and interaction with other intracellular organelles.
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PMID:Phospholipid transfer between vesicles. Dependence on presence of cytochrome P-450 and phosphatidylcholine-phosphatidylethanolamine ratio. 628 73

In cultured melanotic melanoma, a marked decrease of pigmentation has been found to be induced by the addition of tunicamycin [Y. Mishima and G. Imokawa (1983) J. Invest. Dermatol. 81, 106-114]. Since it appears that this impaired pigmentation arises from the loss of asparagine-linked sugar chains serving as a signal for transport of tyrosinase from GERL (Golgi-associated endoplasmic reticulum of lysosomes) to premelanosomes, tyrosinases from the membrane fraction of Greene's hamster melanoma have been purified, and the structures of their sugar chains have been analyzed. Two kinds of tyrosinases were purified by Triton X-100 solubilization; DEAE-cellulose, Sephadex G-200, and DEAE-Sephadex column chromatography; and preparative polyacrylamide gel electrophoresis. The two tyrosinases were separated by polyacrylamide gel electrophoresis, and both corresponded to Mr 69,000. Their asparagine-linked sugar chains were released by hydrazinolysis and analyzed. The sugar chains of the two tyrosinases were identical except for the sialic acid contents. One mole of each tyrosinase contained 1 mol of high-mannose-type sugar chains and 3 mol of complex-type sugar chains. The former chain has Man3 approximately 5 X GlcNAc2 and the latter has Man3 X GlcNAc beta 1----4(+/- Fuc alpha 1----6)GlcNAc as their core structures. The complex-type sugar chains are composed of mono-, bi-, tri-, and tetraantennary sugar chains, with +/- Sia alpha 2----3Gal beta 1----4GlcNAc beta 1----as their outer chains.
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PMID:Purification of hamster melanoma tyrosinases and structural studies of their asparagine-linked sugar chains. 643 39

The regulation by the cell of subcellular membrane components is dependent on a highly complex balance of nutritional, hormonal and metabolic events. We have characterized the lipid components of the endoplasmic reticulum (ER) of the liver of adrenalectomized (ADX) rats and the response of these membrane components to glucocorticoid administration. Membrane microviscosity as measured by fluorescence depolarization of 1,6-diphenylhexatriene (DPH) was measured and correlated with lipid composition and content of the membranes. In the ADX rat, a significant increase in membrane microviscosity of the smooth endoplasmic reticulum (SER) was observed and this was accompanied by an increase in the cholesterol content/mg protein and a decrease in the phospholipid content/mg protein. A change in the fatty acyl chain composition is observed with a significant increase in the mole percentage of arachidonic acid (20:4) and an accompanying decrease in saturated fatty acids. Within 2-6 hr of dexamethasone administration, a decrease in membrane microviscosity is observed that returns this value to one similar to that for normal control animals. Both the cholesterol and the phospholipid contents/mg protein are likewise restored to levels similar to that for control animals beginning at the 2-hr time point. The arachidonic acid and saturated fatty acid content of the constituent phospholipids do not begin to return to values similar to those for control animals until 6 hr after dexamethasone administration. From these experiments, we can conclude that glucocorticoids play a significant regulatory role in determining the lipid properties of rat hepatic microsomal membranes.
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PMID:Dynamic lipid changes in rapidly proliferating hepatic smooth endoplasmic reticulum during acute dexamethasone treatment of adrenalectomized rats. 721 73

The ultrastructure of the pinealocytes in the fetal mole (Talpa europaea) was examined and compared with that in the adult mole. The parenchyma of the fetal pineal gland consists primarily of pinealocytes with very few dispersed "glial" cells. Three different morphological types of pinealocytes (I, II and III) were observed. Pinealocytes of types I and II, homologous to the rudimentary photoreceptor cells of lacertilians and birds, were commonly found, especially around the pineal lumen, which is still present in the fetus. These results support the concept of the phylogenetic origin of mammalian pinealocytes from the pineal photoreceptor cells of the nonmammalian vertebrates. Considering their synthetic/secretory activity, the pinealocytes of the mole fetus are characterized by the presence of accumulations of proteinaceous material (APM) in the cisternae of the granular endoplasmic reticulum (GER). Two types of APM were also found. One type shows a paracrystalline organization as described in the adult mole. In the fetus, however, the paracrystalline-organized APM occur only infrequently. A progressive transformation, via an increase in size or fusion of vacuoles containing material originating from the cisternae of the GER in APM, free of a paracrystalline structure, has been observed. Granular vesicles (GV) originating from the Golgi saccules were rarely observed. Sometimes GV and APM were found to be present in the same cell.
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PMID:The pineal gland of the mole (Talpa europaea L.). 738 98

We examined by light and electron microscopy five melanocytomas from four patients. Two types of cells were observed in each tumor. The predominant cell type in most of the tumors studied consisted of plump polyhedral nevus cells that contained numerous giant melanosomes. These cells showed advanced differentiation. They appeared to be metabolically inactive and to have been the cause of the heavy pigmentation and benign nature of these tumors. The second variant of melanocytoma cells were smaller spindle-shaped cells that were lightly pigmented. Other morphologic features of these cells such as high nucleus-cytoplasm ratio, prominent nucleolus, nuclear membrane infolding, numerous mitochondria, prominent rough endoplasmic reticulum, and free ribosomes, indicated a metabolically active cell, which may explain the infiltrating behavior of these tumors.
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PMID:An ultrastructural study of melanocytomas (magnocellular nevi) of the optic disk and uvea. 739 58

The testicular structure of the wild caught naked mole rat was studied. It comprises of a large volume of lipid-rich interstitial cells of Leydig among which are few scattered seminiferous tubules. In addition, the interstitial cells possess elongated mitochondria and vast network of smooth endoplasmic reticulum (sER). The Golgi apparatus (GA) apparently is not conspicuous or well developed. All stages of spermatogenesis occur in the seminiferous tubules although the mature forms (secondary spermatocytes, spermatids and spermatozoa) are few. Sertoli cells show an irregular nucleus, mitochondria oriented perpendicular to the basement membrane, a vast network of endoplasmic reticulum with sER as the predominant form and lipid droplets. The ultrastructural features of Leydig cells seem to suggest a steroidogenic capacity although the vast accumulation of lipid droplets may imply impaired utilisation of cholesterol reservoir as a result of pituitary hormonal imbalance or (and) the local paracrine influence by Sertoli cells. The cause of slow-down in spermatogenesis is still unclear but may also be under the influence of pheromonal cues or the local paracrine control. Sertoli cell features point towards a role of synthesis and secretion.
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PMID:Ultrastructural study of the testis of non-breeding naked mole-rat (Heterocephalus glaber, Ruppell). 825 Feb 73

Cytotoxic T lymphocytes (CTL) recognize peptides in association with major histocompatibility complex (MHC) class I proteins, but how peptides bind to class I is not well understood. We used a fluorescence technique to measure antigenic peptide binding to a soluble, single-chain Kd (SC-Kd) molecule in which the Kd heavy chain was connected by a 15-residue link to beta 2-microglobulin. Peptides were covalently labeled at their N terminus with dansyl, and binding of dansylated Kd-restricted peptides to SC-Kd resulted in significant fluorescence enhancement, which could be inhibited by unmodified Kd-restricted peptides. Real-time binding of a dansylated peptide could be followed by monitoring the fluorescence at 530 nm. The dansylated Plasmodium berghei circumsporozoite (PbCS) 263-260 peptide bound to "empty" SC-Kd with an association rate constant of 1140 M-1s-1, and the subsequent spontaneous dissociation of the SC-Kd-peptide complex was slow. The dissociation increased dramatically after addition of excess unlabeled PbCS 253-260 peptide, but with a slower association constant for unlabeled peptide, 77 M-1s-1. Thus, the Kd-peptide complex on the surface of antigen-presenting cells should be stable, but high concentrations of peptides in the endoplasmic reticulum (ER) lumen would allow for peptide exchange on Kd before export to the surface. The apparent activation energy for PbCS 253-260 peptide binding to SC-Kd was 6.78 +/- 0.64 kcal/mole, similar to values previously reported for antigen-antibody interactions.
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PMID:Real-time measurement of antigenic peptide binding to empty and preloaded single-chain major histocompatibility complex class I molecules. 847 6


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