Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The small-angle X-ray scattering curves, CD spectra and textures of the liquid-crystalline phase formed from poly(I).poly(C) molecules in a water-salt solutions containing poly(ethylene glycol) at different temperatures were obtained. It was found that the heating of poly(1).poly(C) liquid-crystalline phase is accompanied by two types of transitions, the first one--a "cholesteric----"compensated" structure----cholesteric", the second--a "cholesteric----isotropic state" transition. The latter transition takes place at a temperature that corresponds to that of the separation of chains of the double-stranded poly(I).poly(C) molecule.
Mol Biol (Mosk)
PMID:[2 types of temperature transitions in liquid crystals formed from poly(I).poly(C) molecules]. 368 81

Previous studies have shown that administration of ethylene glycol monomethyl ether (EGM) to the rat results in testicular damage with the spermatocyte being the primary cellular site for toxicity. An ultrastructural study has now been carried out to characterize the early subcellular changes following a single dose of 250 or 500 mg EGM/kg body weight. At 12 and 18 hr after dosing, large membrane bound intracellular vacuoles filled with flocculent or granular material were observed in the basal region of the tubules. These mostly appeared to originate as rarefaction and swelling of Sertoli cell processes. Necrosis of spermatocytes was evident at 12 hr but the process of cell death was rapid with cells either appearing normal or in an advanced state of necrosis. Many of the spermatocytes which appeared otherwise normal, showed areas of plasma membrane dissolution, a change which was also seen affecting the facing Sertoli cell plasma membrane resulting in continuity of the cytoplasm between the two cells. This membrane change was seen in the absence of any other morphological abnormality in the affected spermatocyte, although slight mitochondrial condensation was sometimes also present. By 24 hr after dosing, most of the spermatocytes in the spermatogenic stages which had shown the earlier membrane changes, had become necrotic while Sertoli cell vacuolation had largely regressed. Although the membrane dissolution was an early and specific effect, it is regarded as part of the phagocytic response of the surrounding Sertoli cell. It is suggested that the vacuolar changes in the Sertoli cell may be causally associated with spermatocyte injury.
Exp Mol Pathol 1986 Dec
PMID:An ultrastructural study of ethylene glycol monomethyl ether-induced spermatocyte injury in the rat. 379 14

A quantitative study has been carried out to characterize the stage susceptibility of the spermatocyte to ethylene glycol monomethyl ether (EGM) toxicity. EGM was administered as a single oral dose of 250 mg/kg body wt and rats were examined at time periods after dosing. The number of spermatocytes and round spermatids in tubules at each stage of spermatogenesis was counted. A sharp transition in susceptibility was observed between zygotene spermatocytes in stage XIV which showed no effect and pachytene spermatocytes in stage I which showed death or depletion of 70% of its population after 1 day. A similar transition was seen between dividing spermatocytes and step 1 spermatids, the latter being unaffected. There was a gradual reduction in susceptibility toward midpachytene such that cells in stages VII-XI showed no effect. Analysis of later time periods revealed no effect on spermatogonia or prepachytene spermatocytes but did indicate that midpachytene spermatocytes underwent delayed cell death after further progression through the cycle. In a separate sequential morphological study of early changes, the earliest signs of necrosis were seen 12 hr after dosing and were restricted to spermatocytes in stages V, XI, and XII. Cell death then progressed in a wave-like manner through stages XIII and XIV finally reaching stage I, 24 hr after dosing.
Exp Mol Pathol 1985 Dec
PMID:A quantitative study of stage-specific spermatocyte damage following administration of ethylene glycol monomethyl ether in the rat. 406 11

The responsiveness of anterior pituitary tumor (GH3) cells to promoters of prolactin secretion and/or synthesis and cyclic AMP accumulation was studied as a function of cellular Ca2+ content. GH3 cells exposed to media containing 1 mM ethylene glycol bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid were reduced 7-fold in Ca2+ content without loss of viability. Preparations of Ca2+-depleted cells were largely unchanged in cyclic AMP content when challenged by thyrotropin-releasing hormone (TRH), whereas cells which were subsequently restored at optimal Ca2+ (0.5 mM) responded to the hormone with 2- to 3-fold increases in cyclic AMP content. The decreased responsiveness of Ca2+-depleted cells to TRH was not influenced by phosphodiesterase inhibitors, incubation time, or hormone concentration. TRH-dependent cyclic AMP accumulation was markedly potentiated by forskolin in Ca2+-restored, but not in Ca2+-depleted, cell preparations. Forskolin extended the time period during which cyclic AMP accumulated in response to TRH without altering the TRH concentration dependency of the cells. Varying increases in GH3 cyclic AMP content occurred in response to other hormones or agents which enhance prolactin secretion and/or synthesis. In Ca2+-restored cells, cyclic AMP content was increased 2-fold by prostaglandin E1 (PGE1) and epidermal growth factor (EGF), 10- to 15-fold by vasoactive intestinal polypeptide (VIP) and 6-fold by phorbol myristate acetate (PMA); the capacity of Ca2+-depleted cells, however, to accumulate cyclic AMP in response to PGE1, EGF, and VIP was greatly reduced. Accumulation of cyclic AMP following short-term incubations with cholera toxin similarly was dependent on Ca2+. Exposure of GH3 cells preloaded with 45Ca to TRH, PGE1, EGF, PMA, or VIP resulted in losses of cell-associated 45Ca. Pretreatment with these agents resulted in a decreased capacity of the cells to accumulate 45Ca from the extracellular medium. The results of this study support the hypothesis that various putative humoral regulators of prolactin secretion and/or synthesis act on GH3 cells to alter intracellular Ca2+ metabolism which in turn results in an increased cyclic AMP content through stimulation of adenylate cyclase activity.
Mol Pharmacol 1983 Mar
PMID:Regulation of Ca2+-dependent cyclic AMP accumulation and Ca2+ metabolism in intact pituitary tumor cells by modulators of prolactin production. 630 Jun 49

A spot test has been developed for detecting substances that enhance the transposition of Tn9 in Escherichia coli. Phage lambda::Tn9-infected cells were plated on chloramphenicol media and a drop of the test substance was placed at the center of the plate. Following incubation, chloramphenicol-resistant colonies appeared due to the transposition of Tn9 to the bacterial chromosome. By comparing the test plate and a control plate with respect to the number and distribution of colonies, the effect of the test compound can be evaluated. Out of over 100 compounds tested, acetate, two detergents (Brij 58 and Nonidet P40) and dimethylsulfoxide were found to enhance transposition 3-20 fold. Acetate was also found to enhance the transposition of Tn5 and Tn10. The stimulating effect of Brij 58 was lost when palmitic acid was added with the Brij 58. The nature of these substances, which we refer to as "transposagens", suggests an involvement of lipid or membrane in the transposition process.
Mol Gen Genet 1983
PMID:Detection of chemicals that stimulate Tn9 transposition in Escherichia coli K12. 630 65

The results demonstrate the presence in cod serum of beta 2-microglobulin (beta 2m)-binding molecules. Upon fractionation on Sephadex G-200, the bound beta 2m appears mainly in the void volume, but also as a minor peak with the apparent size of albumin. The complexes show affinity to Con A-Sepharose and Lens culinaris lectin-Sepharose, respectively, indicating that they contain glycoproteins. Because of the high molecular weight of the beta 2m-containing complexes they can be separated from unbound beta 2m by polyethyleneglycol (PEG-6000) precipitation, thus allowing rapid analysis. These beta 2m-binding molecules exhibited size- and charge-homogeneity when separated by gel filtration (Sepharose 4B) and by ion-exchange chromatography (DEAE-cellulose), respectively. The binding is temperature-dependent. At 37 degrees C, maximum binding is reached after about 2 hr. The dissociation is considerably slower, complete dissociation taking about 2 days. According to Scatchard analysis, the association constant is of the order 2 X 10(9)/M. The binding is sensitive to denaturating agents and high salt concentrations. Optimum binding is seen at neutral pH and the beta 2m-binding activity is heat-labile at 50 degrees C. The binding of heterologous beta 2m by cod serum can be used as a cross-reactive assay specific for the detection of beta 2m. Whereas unlabelled human, guinea-pig, and rat beta 2m all give similar inhibition, higher concentrations of rabbit beta 2m are needed for the same degree of inhibition.
Mol Immunol 1983 Aug
PMID:Binding of mammalian beta 2-microglobulin by glycoproteins in fish serum. 635 6

Human intraspecific hybrids were formed between tumor cells isolated from both primary and metastatic tumors and a tissue culture adapted cell line, D98OR, a HeLa derivative which is thioguanine and ouabain resistant. Five different tumor types in all were attempted: renal cell carcinoma, colon adenocarcinoma, melanoma, chrondrosarcoma, and hepatocarcinoma. The tumor tissue was either (1) immediately dissociated and fused, or (2) frozen and later thawed, dissociated, and fused. Two different PEG concentrations were used. The results reported here demonstrate that: (1) hybrid tumor cell lines can be made from several types of cancer, (2) unfrozen tumor tissue fused with D98OR by exposure to 50% PEG appears optimal, (3) chromosome loss, as determined by flow cytometry studies of hybrid DNA content, is minimal, and (4) hybrids have characteristics consistent with derivation from tumor cells rather than derivation from the nonmalignant cells of a tumor.
Somat Cell Mol Genet 1984 Mar
PMID:Somatic cell hybridization of human tumor samples. 658 90

Phosphocalmodulin (PCaM) was identified after analysis of calmodulin (CaM) preparations by two-dimensional gel electrophoresis by using a modified ampholyte system to resolve very acidic proteins. The analysis of CaM prepared by the conventional procedure based upon its heat resistance and acidity as well as the analysis of whole urea extracts from brain showed that PCaM was a major component in this tissue. PCaM was 1 pH unit more acidic than CaM, and its electrophoretic mobility, unlike CaM, was not changed by either calcium or ethylene glycol-bis(beta-aminoethyl ether)-N,N-tetraacetic acid. In urea extracts of brain prepared in buffers containing phosphate and sodium fluoride, PCaM was as prominent as CaM; it was partially converted into CaM after elution from the gel and reelectrophoresis. Amino acid analysis of PCaM and CaM purified by two-dimensional gel electrophoresis showed the same composition for the two proteins, including their trimethyllysine content. Incorporation of 32P occurred exclusively into the acidic variant when brain slices were incubated with H332PO4; amino acid analysis showed that the phosphate was bound to serine residues. CaM was found also to be phosphorylated in vitro by a phosphorylase kinase preparation from skeletal muscle.
Mol Cell Biol 1983 Aug
PMID:Evidence for a phosphorylated form of calmodulin in chicken brain and muscle. 662 32

The spatial organization of histone dimer H2A-H2B in a solution of 0.1-1.0 M NaCl is characterized by the inclusion of 38% of radicals in the composition of alpha-helical segments, fluorescence quantum yield of 0.085 +/- 0.003, long-wave shift of absorbtion (lambda max = = 278.4 +/- 0.5 nm) and fluorescence spectra (lambda max = 304.4 +/- 0.3 nm) as compared to respective spectra of free tyrosine. The changing of position lambda max of tyrosine fluorescence of histones during denaturation has been shown. The degree of alpha-helicity of histone dimer H2A-H2B, fluorescence quantum yield and the number of tyrosyls perturbed by ethylene glycol do not change within the range of 0.1-1.0 M NaCl pH 7.6. At the same time dimer denaturation takes place at greater urea concentrations as the ionic strength of the medium increases. The quenching of tyrosine fluorescence of histone dimer H2A-H2B was performed using ions I-, Cs+ and acrylamide. It has been shown that, at a concentration of NaCl 0.5 M, dimer compactization takes place, as well as the screening of some part of tyrosyls for the quenching effect of Cs+. Our experiments made it possible to identify three zones in the composition of histone dimer H2A-H2B and determine the number (ni) and fluorescence quantum yields (qi) of tyrosyls included in the following specific zones:zone I--n1 = 2, q1 = 0.136, zone II--n2 = 3, q2 = 0.08, zone III--n3 = 3, q3 = 0.055.
Mol Biol (Mosk)
PMID:[Spatial organization of the histone dimer H2A-H2B in solutions of different ionic strengths]. 663 32

Polyethylene glycol-mediated fusion of Chinese hamster ovary (CHO) cells with mouse Cl1D cells produced interspecific somatic cell hybrids which slowly segregated CHO chromosomes. Cytogenetic and isozyme analysis of HAT- and bromodeoxyuridine-selected hybrid subclones and of members of a hybrid clone panel retaining different combinations of CHO chromosomes enabled provisional assignments of the following enzyme loci to CHO chromosomes: TK, GALK, and ACP1 to chromosome 7; TK and GALK to chromosome Z13; ACP1, ADA, and ITPA to chromosome Z8; and ADA and ITPA to chromosome Z9. These genetic markers reflect the origin of each of these Z group chromosomes and indicate the functional activity of alleles located on rearranged chromosomes. Identification of diploid electrophoretic shift mutations for ADA and ITPA was consistent with those observations. Assignment of the functional TK locus in TK+/- CHO-AT3-2 cells indicated that gene deletion may be responsible for TK hemizygosity in this subline.
Mol Cell Biol 1983 Nov
PMID:Genetic effects of chromosomal rearrangements in Chinese hamster ovary cells: expression and chromosomal assignment of TK, GALK, ACP1, ADA, and ITPA loci. 665 61


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