Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:Q9UIJ5 (Rec)
 58,342 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Electron microscopic observations and measurements were made on thin-sectioned chromatin fibers and fibrils obtained from nuclei of mature chicken erythrocytes. The nuclei were isolated in low ionic strength gum arabic and octanol then extracted sequentially with (1) 0.14 M NaCl, (2) 0.25 N HCl, (3) buffer saturated phenol, (4) hot 5% SDS and 0.14 M 2-mercaptoethanol and, (5) 0.4 N NaOH. The amount of nuclear protein removed at each of the first four extraction steps was 1, 86, 3 and 11% of the total, respectively. Each extract was characterized by electrophoretic profiles. At each extraction the chromatin was fixed by adding large quantities of a mixture of equal volumes of sodium cacodylate buffered 8% (w/v) glutaraldehyde (pH 6.8) and 2% OsO4 (w/v), directly into (1) an aliquot of the chromatin in extraction fluid, and (2) an aliquot of the chromatin after water washing and swelling. Three size classes of chromatin structure were seen in thin sections prepared for high resolution transmission electron microscopy and stained with uranyl acetate and lead citrate. A thick fiber of about 25 + nm diameter was the predominant large fiber seen in freshly isolated nuclei or in nuclei after salt extraction. This 25 + nm fiber has a substructure consisting of 3.2-5.2 nm diameter fibrils. After water swelling of such freshly isolated or salt extracted nuclei a fiber of about 10 nm diameter was the predominant large fiber instead of the 25 nm diameter fiber. The HCl extraction step which is known to remove histones, caused the disappearance of both the 25 nm and the 10 nm fibers. High magnification (600,000 x) micrographs of the chromatin at all procedural steps, except the last NaOH step, reveal the fibril to be omnipresent. This fibril tends to decrease somewhat in diameter during the protein extraction steps to a 2.5 nm diameter fibril after the hot SDS extraction. A fibril of 2.5 nm diameter is expected of naked double helical DNA stained with a positive stain. The NaOH, which is known to denature DNA, completely destroyed the remaining fibril. We inerpret our results to indicate that the larger chromatin fiber seen in micrographs of thin-sectioned chromatin has a fibrillar substructure which probably represents a double coil of native DNA which may have a thin protein coating of its own. The latter fibril may in turn be wrapped around a hydrophobic histone domain, perhaps reflected in the 10 nm diameter fiber which is seen upon swelling of the chromatin. This 10 nm diameter fiber is thought to be further packaged by folding into the 25 + nm diameter chromatin fiber most frequently reported in thin sections of eukaryotic cell nuclei in situ.
Anat Rec 1979 Aug
PMID:Chromatin substructure: an electron microscopic study of thin-sectioned chromatin subjected to sequential protein extraction and water swelling procedures. 47 16

A study was made of the medium conditioned by spontaneously transformed rat embryo fibroblasts of line Rec1-sf, which are capable of unlimited reproduction in medium free of serum and of other endogenous growth factors (c-medium). Addition of c-medium to stationary cultures of nontransformed rat embryo fibroblasts (REF), spontaneously transformed REF (line Rec1), and cells of Rec1-sf stimulated the incorporation of 3H-thymidine by 1.5-6 times. SDS-polyacrilamide-gel electrophoresis of proteins, marked by 35S-metionine of c-medium of the cell line Rec 1-sf, demonstrated that this medium had proteins with molecular mass from 10 to 110 kDa. The fractionating divisible by 100 ultra-concentrates of c-medium with utilization of heparin-sepharose allowed to isolate two types of heparin-binding proteins. The proteins of the first type took about 5% of all the proteins of c-medium; they were eluted with 1.1 M NaCl and stimulated the incorporation of 3H-thymidine in REF, Rec1 and Rec1-sf cultures by 1.3-1.9 times. The second type proteins took about 1% of all the proteins of c-medium and were eluted with 2M NaCl, and, like the main endogenic basic growth factor of fibroblasts, stimulated the incorporation of 3H-thymidine into REF and Rec1-sf, but not into the culture of Rec1 line cells. The results obtained are discussed in terms of a hypothesis of autocrine regulation of cell proliferation.
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PMID:[The autocrine regulation of proliferation in cell cultures. I. A study of the heparin-binding factors with growth-stimulating activity contained in media conditioned with transformed rat fibroblasts]. 171 6

A murine monoclonal IgM antibody, M3, which interferes with both polymorphonuclear leukocyte (PMN) phagocytosis and bactericidal activity, was used to examine the subcellular location of antigens bearing 3-fucosyllactosamine (CD15 antigens) within this cell type. Percoll gradient-separated secondary granule fractions were rich in CD15 antigens, with at least seven antigens recognizable in SDS-PAGE/electroblot studies. Sonication/sedimentation experiments using secondary granule fractions showed that both soluble and sedimentable CD15 antigens were present. Exposure of purified PMN to the secondary granule secretagogue phorbol myristate acetate caused extracellular release of two or three CD15 antigens, which could be purified by immunoprecipitation using antibody M3. Triton X-114 phase-partition experiments showed that secondary granule fraction CD15 antigens could be partitioned into hydrophilic (aqueous phase) and hydrophobic (detergent phase) antigens, suggesting that several of these antigens were integral secondary granule membrane components. Ultrastructurally, PMN intracellular granules showed two patterns of CD15 expression, localization over both granule matrix/granule membrane and localization to only granule membrane. Colocalization studies showed that lactoferrin and CD15 antigens were both present in a subset of intracellular granules, confirming a secondary granule location for these antigens.
Anat Rec 1990 Nov
PMID:Functional, physical, and ultrastructural localization of CD15 antigens to the human polymorphonuclear leukocyte secondary granule. 197 22

Two types of DNA ligase, I and II, have been purified approximately 4,000-fold from mouse testes and 500-fold from nuclei of mouse spermatocytes. DNA ligase I and II consisted of single polypeptides with molecular weights of 95,000 and 65,000, respectively, according to the estimation by SDS-polyacrylamide gel electrophoresis and the AMP-binding assay. Ligase activities were higher in premeiotic spermatogonia and spermatocytes than those in liver and bone marrow cells. Moreover, DNA ligase II showed rapid increase during meiotic prophase and a decrease in round spermatids. Since this behavior of DNA ligase II is consistent with that of m-rec and DNA polymerase beta, both of which have been shown to be involved in DNA recombination in meiotic cells, DNA ligase II might be an enzyme which works at the final step of meiotic recombination reaction.
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PMID:Purification of DNA ligases from mouse testis and their behavior during meiosis. 234 May 90

The distribution of monomeric and polymeric actin in spermatozoa from the bull, boar, rabbit, human, rat, mouse, golden hamster, and guinea pig has been examined by using a monoclonal antiactin antibody and NBD-phallacidin. Actin was present in sperm from each species. When the monoclonal antibody was used, there was a species-specific distribution and intensity of fluorescence, but no generalized pattern. Specific fluorescence was noted in the neck and principal piece of human sperm; in the postacrosomal region, neck, and midpiece of bull and boar sperm; in the postacrosomal region, neck, and principal/equatorial segment border of rabbit sperm; in the neck region of hamster sperm; and in the neck, midpiece, and principal piece of rat, mouse, and guinea pig sperm. Sperm from all eight species displayed no specific fluorescence with NBD-phallacidin, indicating that actin was present in a nonfilamentous form. SDS extracts of sperm were analyzed by SDS-PAGE and Western blotting; in sperm from each species, a 42-kD protein with specific affinity for the monoclonal antibody was present.
Anat Rec 1986 Dec
PMID:Localization of actin in mammalian spermatozoa: a comparison of eight species. 243 4

The pattern and timing of the breakdown and loss of matrix proteins were studied in developing rat incisor enamel using sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), fluorography, radioautography, and in vitro incubations of proteins isolated from freshly dissected, crushed pieces of enamel. For biochemical studies, the technique of Robinson et al. (1974, 1977, 1983) was used to transect the enamel organ and enamel into a series of strips at 1 mm intervals along the length of the tooth. The proteins in each strip were extracted and either quantified by Lowry analysis or applied to 12% slab (enamel) or 5-15% continuous gradient (enamel organ) SDS-polyacrylamide gels and separated by electrophoresis. The biochemical studies indicated that the amount of protein contained within an enamel strip increased gradually by volume across the secretory stage, reached a peak early during the maturation stage, and then declined rapidly thereafter. The distribution of enamel proteins on SDS-polyacrylamide gels changed markedly throughout this period. These changes included increases and decreases in the intensity of staining of proteins at certain molecular weights (e.g., 18 kDa) and the appearance and disappearance of some proteins not seen clearly near the start of the secretory stage of amelogenesis (e.g., 32 and 10 kDa). Labeling studies with 35S-methionine suggested that the "stacked" arrangement of proteins typical of forming enamel (secretory stage) actually represented a very dynamic association of proteins, with new ones being added at the top of the stack and then breaking down with time to become those seen at lower molecular weights. Across the secretory stage, new proteins were always added to the top of the stack, but during early maturation this activity slowed dramatically, allowing the breakdown of aging proteins to be visualized more clearly. Radioautographic studies with 3H-methionine indicated that the breakdown of newly secreted proteins also was correlated with a movement of label from the site of secretion into deeper, previously unlabeled, areas of forming enamel. In vitro studies revealed that the rate and degree of breakdown of enamel proteins varied markedly, depending on the stage of amelogenesis from which the proteins were extracted. Secretory stage enamel proteins showed slow in vitro degradation with accumulation of proteins near 18 kDa. Early maturation stage enamel proteins showed more rapid breakdown with little accumulation of proteins near 18 kDa, whereas late maturation stage enamel proteins showed complete degradation by 2 days of incubation in vitro.(ABSTRACT TRUNCATED AT 400 WORDS)
Anat Rec 1989 Jun
PMID:Degradation and loss of matrix proteins from developing enamel. 277 8

Lactoferrin (Lf) in blood and/or marrow neutrophils was semiquantified using indirect immunofluorescence technique in nine mammalian species. Neutrophil iron-binding reactivity (NFeBR), which corresponds primarily to Lf, was also visualized and semiquantified using functional cytochemical (FeNTA-AF) technique at the light microscopic level in these nine and in an additional fifteen mammalian species, and in selected species at the ultrastructural level. Neutrophil immunoreactive Lf was positively correlated with total cellular and granule content of NFeBR among these nine species, and with previously reported concentrations of neutrophil Lf quantified by radioimmunoassay. Relative levels of Lf in neutrophil extracts from rat, hamster, and human were confirmed using SDS-polyacrylamide gel electrophoresis and immunoblotting. Relatively high levels of immunoreactive neutrophil Lf and/or NFeBR were observed in carnivores (ten species) and primates (six species). Among rodents (five species), the levels were variable, and the artiodactyls (four species) studied had low levels. These results demonstrate that neutrophil Lf levels vary widely among mammalian species. In addition, FeNTA-AF technique provides a rapid means of evaluating animals for relative quantities of neutrophil Lf.
Anat Rec 1988 Jun
PMID:Neutrophil lactoferrin content: variation among mammals. 304 35

Mammalian spermatozoa have previously been shown to contain actin, but its subcellular localization and function have not been elucidated. In this study, actin has been localized at the ultrastructural level in human, bull, rabbit, and golden hamster spermatozoa by a monoclonal antiactin antibody and a preembedding immunogold labeling technique. Specific labeling was localized 1) around the connecting piece in the neck region of sperm from all four species, although a species-specific pattern was evident; 2) on the external surface of the fibrous sheath of human sperm; 3) in the perinuclear space underlying the postacrosomal sheath of bull and rabbit sperm; and 4) between the plasma membrane and outer acrosomal membrane along the concave margin of the hamster sperm head. SDS-PAGE and Western blots immunostained with the monoclonal antibody confirmed the presence of actin in SDS extracts of Percoll-purified sperm from each species.
Anat Rec 1988 Jun
PMID:Localization of actin in human, bull, rabbit, and hamster sperm by immunoelectron microscopy. 341 83

Inside-out (I.O.) vesicles isolated from human erythrocyte ghosts induced to endocytose have been used for biochemical studies to determine localization of molecules within the membrane. It was the purpose of this study to examine such vesicles by freeze-etch electron microscopy to determine the architecture of the peripheral proteins on the protoplasmic surface. Examination of the I.O. vesicles while still in the interior of the ghosts showed that a globular material was randomly distributed on the outer surface (protoplasmic surface of the original plasma membrane) of the I.O. vesicles. The random distribution of the globular material becomes altered, however, if the I.O. vesicles are isolated from the ghosts by shearing and centrifugation. Freeze-etching of these isolated I.O. vesicles revealed that the globular material was now clustered on the protoplasmic surface (PS), as were the intramembranous particles (IMPs) in the extracellular face. Thus, the lateral mobility of the IMPs is dependent upon the distribution of molecules at the protoplasmic surface of the membrane. Moreover, this change in distribution of the globular material at the surface is not due to a partial loss of major membrane proteins, because SDS-polyacrylamide gel electrophoresis revealed that equal amounts of the major proteins were present in nonisolated vesicles as compared to isolated vesicles. Although isolated I.O. vesicles have been used extensively to demonstrate that glycoproteins span the membrane, these results suggest that one should cautiously interpret data obtained from such isolated vesicles in view of the fact that there is an alteration of the distribution and perhaps configuration of molecules at the PS following isolation of I.O. vesicles.
Anat Rec 1982 Mar
PMID:Isolation of human erythrocyte inside-out vesicles alters their molecular architecture. 707 79

The region of epithelial apposition with a tooth surface is the site of an unusual stratified integument, the junctional epithelium, which combines tight attachment to the tooth, cell turnover, tissue permeability, and epithelial versatility into the first line of defense against periodontal destruction by oral pathogens. To better understand the structure and function of the junctional epithelium we have reviewed its developmental and cell biology, and undertaken a multidisciplinary analysis of its composition in the pig, an omnivore whose dietary and dental development and occlusion patterns are similar to the human condition, and which, because of its size, is more readily amenable to experimental manipulation. The porcine junctional epithelium was also compared with this well-described epithelium in the rat. Morphological analyses by light microscopy and scanning and transmission electron microscopy showed the porcine junctional epithelium and epithelial attachment were similar to that in the rat except that apically, extracellular matrix lamellae associated with the internal basal lamina were more complex, and more coronally there was extensive layering of a dental cuticle-like material. Biochemical analysis of the porcine junctional epithelium by dissociative extraction and SDS-PAGE revealed the presence of some proteins not present in gingival epithelium. Together, these studies show that the porcine junctional epithelium has predictable morphological and biochemical features which establish the pig as an advantageous model to study the basic and clinical biology of this unique epithelium.
Anat Rec 1994 Jan
PMID:The epithelial attachment and the dental junctional epithelium: ultrastructural features in porcine molars. 811 83


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