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)

A selection of lectins was used to investigate developmentally regulated changes in the distribution of cell surface oligosaccharides during the gastrulation and neurulation stages of early chick embryo development. Lectins from three specificity classes were used: glucose/mannose specificity (concanavalin A [Con A], Lens culinaris agglutinin [LCA], Pisum sativum agglutinin [PSA]); N-acetylglucosamine specificity (Lycopersicon esculentum agglutinin [LEA], wheat germ agglutinin [WGA], succinylated WGA [sWGA]); N-acetylgalactosamine/galactose specificity (Dolichos biflorus agglutinin [DBA], soybean agglutinin [SBA], Sophora japonica agglutinin [SJA], Bandeiraea (Griffonia) simplicifolia lectin I [BSL I], peanut agglutinin [PNA], Artocarpus integrifolia lectin [Jacalin], Ricinus communis agglutinin-1 [RCA-1], Erythrina cristagalli lectin [ECL]). At gastrulation stages, patterns of lectin binding could be distinguished in the epiblast, mesoderm, and endoderm cell layers. The primitive streak failed to bind any of the lectins, but LEA and WGA bound to the epiblast in regions lateral to the streak, indicating the loss of some glucosamine residues medially in preparation for the ingression movements of gastrulation. Several lectins showed marked binding to the mesoderm cells after their passage through the primitive streak; these were LCA, PSA, WGA, sWGA, BSL, and most particularly PNA. Therefore, the epithelial-mesenchymal transformation from epiblast to mesoderm at the primitive streak is accompanied by cell surface oligosaccharide changes in the epiblast and mesoderm that involve all classes of lectins including the PNA-binding sequence Gal beta 1-3GalNAc. Ultrastructurally, PNA was shown to bind extracellularly to matrix fibrils. Jacalin, having the same sugar specificity as PNA, but binding to serine/threonine linked chains rather than asparagine linked chains showed no binding to the mesoderm.(ABSTRACT TRUNCATED AT 250 WORDS)
Anat Rec 1991 Oct
PMID:Changes in glycoconjugate expression during early chick embryo development: a lectin-binding study. 174 24

Biochemical analyses and immunocytochemistry were used to examine the developmental appearance of a major approximately 66 kDa bone phosphoprotein (66 kDa BPP) in the mid-diaphyseal region of embryonic and post-natal chicken tibiae in vivo. Total protein and O-phosphoserine (Ser-P) and O-phosphothreonine (Thr-P) content of 8-, 12-, and 18-day embryonic, and 4-wk post-natal chicken tibiae were determined by amino acid analysis. Similar bone samples were carried through a wide variety of tissue-processing regimes including different protocols for fixation, decalcification, dehydration, and embedding prior to electron microscopy. For immunocytochemistry, tissue sections were incubated with a polyclonal antibody raised in rabbits against 66 kDa BPP, and the antigen was revealed by the high-resolution protein A-gold technique. Amino acid analysis, Western blotting, and immunocytochemistry all showed the presence and increasing concentration of bone phosphoprotein with advancing developmental age. Immunogold labeling was observed over osteoblasts and mineral deposits throughout the bone with the most intense reaction occurring at the mineralization front in embryonic tibiae. Electron probe X-ray microanalysis confirmed the association of 66 kDa BPP with mineral. The levels of phosphoprotein in the tissue were directly correlated with increasing degrees of mineralization. These observations are consistent with previous proposals suggesting that phosphoproteins may play a significant role in the calcification of bone matrix.
Anat Rec 1990 Sep
PMID:Developmental appearance and ultrastructural immunolocalization of a major 66 kDa phosphoprotein in embryonic and post-natal chicken bone. 224 Jun 4

Embryonic chicken osteoblasts cultured over a 30 day period were used as a model system for studying the expression of bone phosphoproteins during cellular differentiation and the possible role of these proteins in extracellular matrix mineralization. Accumulation of total phosphoprotein in the cultures, as determined by O-phosphoserine (Ser-P) and O-phosphothreonine (Thr-P) amino acid analysis, revealed a greater than 10-fold increase over the 30 day period. Total phosphoprotein synthesis, as assessed by (32P)-, (3H)-Ser-P, and (14C)-Thr-P protein labeling, showed the highest levels concurrent with initial mineral deposition within the matrix. The major phosphoprotein present in chicken bones and synthesized by the cultured osteoblasts had a molecular weight of approximately 66 kDa. This 66 kDa bone phosphoprotein (66 kDa BPP) was purified to homogeneity and was used for antibody production. Application of this antibody in Western blot analysis revealed that 66 kDa BPP was present only in protein extracts of mineralizing cultured osteoblasts and was absent in cultures of non-mineralizing chondrocytes, myoblasts, and tendon fibroblasts. The 66 kDa BPP in vitro accumulated continuously in the extracellular matrix in a manner that paralleled both phosphoprotein synthesis and total phospho-amino acid production. A comparison of the results obtained in vitro to those from developing embryonic tibiae in vivo demonstrated a similar qualitative and temporal expression of phosphoprotein and a continual accumulation of 66 kDa BPP in the matrix with advancing mineralization and developmental age. Ultrastructural immunocytochemistry using the 66 kDa BPP antibody and the protein A-gold technique revealed specific immunolabeling over electron-dense regions of mineralization in the cultures that appeared identical to the distribution of labeling observed in vivo (McKee et al.: Connect. Tissue Res., 21:21-29, 1989; Anat. Rec., 228:77-92, 1990). These results demonstrate that this major 66 kDa BPP was expressed concurrently with other differentiated osteoblast functions and suggests that it may play a role in the initiation or regulation of mineralization.
Anat Rec 1990 Sep
PMID:Expression and ultrastructural immunolocalization of a major 66 kDa phosphoprotein synthesized by chicken osteoblasts during mineralization in vitro. 224 Jun 5

Samples of decalcified chicken bone together with varying concentrations of phosphoproteins from bone or egg yolk (phosvitin) were used in vitro as heterogenous nucleators for the induction of Ca-P apatite crystals. The lag time between exposure of the collagen-phosphoprotein complexes and the time nucleation of crystals occurred decreased as the concentration of Ser(P) and Thr(P) increased. Enzymatic cleavage of the phosphate groups by wheat germ and phosphatase reversed this effort, indicating that the phosphate group per se principally facilitated the nucleation of Ca-P crystals by the phosphoprotein complex and collagen.
Anat Rec 1989 Jun
PMID:Mechanism of calcification: role of collagen fibrils and collagen-phosphoprotein complexes in vitro and in vivo. 267 81

The frequency of genetic exchanges between F' factors and the bacterial chromosome was studied in recombination-deficient Escherichia coli mutants under conditions in which the recombinant F' factors were immediately transferred to new hosts. In a series of double matings, F101-1 thr(+)leu(-) episomes were first transferred into each of four intermediate F(-)thr(-)leu(+) strains carrying various rec alleles. After the original F' donors were killed with phage T6, the F101-1 episomes were then transferred from the intermediate cells to F(-)thr(-)leu(-)Str(R)recA(-) females. Recipients of nonrecombinant episomes formed Thr(+) (Str(R)) colonies, and recipients of recombinant episomes formed Leu(+)(Str(R)) colonies. A comparison of the numbers of Leu(+)(Str(R)) and Thr(+)(Str(R)) colonies shows that recB(-) males formed 18 to 21% and recC(-) formed 47 to 60% of the wild-type level of recombinant episomes that could be detected after transfer. No recombinant episomes were detected using a recA(-) intermediate strain. If the intermediate strains harboring the F101 episomes were purified, allowed to grow for 50 generations, and then mated with the recA(-) recipient, recombinant episomes were transferred at 8% of the wild-type level for recB(-) and 13% for recC(-). In contrast, only 0.4 and 0.6% of the normal number of recombinants were obtained from crosses between Hfr Cavalli donors and the same recB(-) and recC(-) strains. Recombinant episomes were detected with greater frequency among newly formed rec(+), recB(-), and recC(-) partial diploids than in those which were 50 generations old.
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PMID:Recombinant F' factors from Escherichia coli K-12 strains carrying recB or recC. 455 37

The stability of Escherichia coli strains carrying hybrid plasmids which contain ColE1-like replicon and threonine operon genes was studied. It was shown that the main reason for instability is the loss of a plasmid. The second reason for instability is the rec-dependent recombination that leads to formation of new plasmids. All experiments where instability of strains was observed, can be quantitatively described by the model that presumes a random loss of plasmids in cell population with a frequency of about 7.10(-4), which results in diappearance of plasmid-borne cells due to their low growth rate. Instability increases during the stationary phase but it is not easy to quantitatively estimate this process.
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PMID:[Instability study of Escherichia coli strains containing hybrid plasmids with threonine operon fragments]. 629 18

The secretory pathway and kinetics of the secretory process were studied in Brunner's glands of mice after stimulation of secretion with a parasympatho-mimetic drug. Adult male mice were injected with pilocarpine, while unstimulated controls received saline. The animals were subsequently administered an intravenous injection of 3H-threonine, and tissue was prepared for electron microscope autoradiography at intervals ranging from 5 minutes to 2 hours after injection of the radioactive precursor. Stimulation with pilocarpine resulted in discharge of secretory granules, which was reflected in a significantly lower percentage of the cell volume occupied by granules. In both control and stimulated mice, at 5 minutes after injection of 3H-threonine, the highest percentage of silver grains was found over the rough endoplasmic reticulum. The proportion of silver grains over the rough endoplasmic reticulum declined at later intervals, and a peak of labeling was observed over the Golgi apparatus at 1 hour. Labeling of the secretory granules increased in the 1- and 2-hour samples from both control and stimulated mice, although the relative concentration of radioactivity in both Golgi-associated and apical secretory granules was greater in stimulated than control glands at 1 hour. The results suggest that the secretory protein produced by Brunner's glands was synthesized by the rough endoplasmic reticulum and transported to the Golgi apparatus where secretory granules were formed in both stimulated and control glands. Depletion of secretory granules by prior stimulation resulted in no change in the kinetics of arrival of radioactivity in the cell organelles involved in the secretory process. However, the drainage of the radioactive label from the rough endoplasmic reticulum was significantly slower in the stimulated glands than in the controls. The existence of two subcompartments within the rough endoplasmic reticulum is among the possible explanations for the latter observation.
Anat Rec 1983 Jul
PMID:Secretory process in Brunner's glands during recovery from stimulation with a single dose of pilocarpine. 641 94

A RecA/Rad51 homologue from Pyrococcus kodakaraensis KOD1 (Pk-REC) is the smallest protein among various RecA/Rad51 homologues. Nevertheless, Pk-Rec is a super multifunctional protein and shows a deoxyribonuclease activity. This deoxyribonuclease activity was inhibited by 3 mM or more ATP, suggesting that the catalytic centers of the ATPase and deoxyribonuclease activities are overlapped. To examine whether these two enzymatic activities share the same active site, a number of site-directed mutations were introduced into Pk-REC and the ATPase and deoxyribonuclease activities of the mutant proteins were determined. The mutant enzyme in which double mutations Lys-33 to Ala and Thr-34 to Ala were introduced, fully lost both of these activities, indicating that Lys-33 and/or Thr-34 are important for both ATPase and deoxyribonuclease activities. The mutation of Asp-112 to Ala slightly and almost equally reduced both ATPase and deoxyribonuclease activities. In addition, the mutation of Glu-54 to Gln did not seriously affect the ATPase, deoxyribonuclease, and UV tolerant activities. These results strongly suggest that the active sites of the ATPase and deoxyribonuclease activities of Pk-REC are common. It is noted that unlike Glu-96 in Escherichia coli RecA, which has been proposed to be a catalytic residue for the ATPase activity, the corresponding residual Glu-54 in Pk-REC is not involved in the catalytic function of the protein.
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PMID:A unique DNase activity shares the active site with ATPase activity of the RecA/Rad51 homologue (Pk-REC) from a hyperthermophilic archaeon. 1006 83

Natural killer (NK) cell function is largely modulated by growth factors and cytokines. In particular, interleukin (IL)-2, IL-12, and IL-15 have major effects on the proliferative and cytotoxic activities of NK cells against tumor and virus-infected cells. It is thought that the members of the protein kinase C (PKC) family of serine/threonine kinases play an important role in mediating the pleiotropic effects of cytokines on their target cells. We have investigated the downstream effects generated in purified human NK cells by IL-2, IL-12, and IL-15 on PKCalpha and PKCepsilon--a canonical and a novel isoform of PKC, respectively. By means of Western blotting, PKC activity assays, and immunofluorescence performed on highly purified preparations of primary human NK cells, we demonstrate that: 1) the three cytokines have similar effects on PKCalpha and PKCepsilon activities; 2) whereas PKCepsilon activity is induced by cytokine stimulation, PKCalpha activity is inhibited; and 3) both the induction of PKCepsilon and the inhibition of PKCalpha functional activity are relatively early events in NK cells, while longer cytokine stimulations do not generate significant variations in enzyme activity, suggesting that the activation of both the canonical and novel isoforms of PKC are events required in the early phases of cytokine-induced NK cell stimulation.
Anat Rec 2002 02 01
PMID:NK-active cytokines IL-2, IL-12, and IL-15 selectively modulate specific protein kinase C (PKC) isoforms in primary human NK cells. 1178 41

Measurements were made of the susceptibility to six commonly prescribed antibiotics, including erythromycin, tetracycline and ciprofloxacin, of 130 isolates of Campylobacterjejuni and 15 isolates of Campylobacter coli cultured from human and poultry sources during 2000. The results were compared with the results from a collection of strains isolated between 1996 and 1998. The levels of resistance to erythromycin remained low, 2 per cent and 4.4 per cent for the human and poultry isolates, respectively. Resistance to tetracycline had increased to 31 per cent and 24.4 per cent from 13.9 per cent and 18.8 per cent for the human and poultry isolates, respectively. However, the resistance to ciprofloxacin of the strains isolated during 2000 had increased to 30 per cent, whereas between 1996 and 1998 there had been no resistance to this agent among human isolates, and only 3.1 per cent resistance among poultry isolates. The molecular basis for this resistance has been shown to be the result of a single amino acid substitution, Thr-86-Ile, in the gyrA subunit of DNA gyrase in Cjejuni. A subset of 59 isolates was tested by molecular methods and all of the 25 phenotypically resistant isolates possessed this substitution. None of the human isolates had been treated with ciprofloxacin before their laboratory isolation.
Vet Rec 2002 Sep 14
PMID:Trends in antimicrobial susceptibility among isolates of Campylobacter species in Ireland and the emergence of resistance to ciprofloxacin. 1257 Mar 15


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