23 results on '"Oka, S"'
Search Results
2. Molecular Cloning of a New Erythropoiesis-Stimulating Activity (ESA36) from Streptomyces thermoviolaceus and Expression in Escherichia coli
- Author
-
Sugie, M., primary, Oka, S., additional, and Tanaka, H., additional
- Published
- 1995
- Full Text
- View/download PDF
3. Cytochrome P450-Butyl Peroxide Complex Detected by ESR
- Author
-
Tajima, K., primary, Edo, T., additional, Ishizu, K., additional, Imaoka, S., additional, Funae, Y., additional, Oka, S., additional, and Sakurai, H., additional
- Published
- 1993
- Full Text
- View/download PDF
4. Production of a novel dimeric 4-deoxy-L-erythro-5-hexoseulose uronic acid by a PL-17 exolytic alginate lyase from Hydrogenophaga sp. UMI-18.
- Author
-
Narsico J, Inoue A, Oka S, and Ojima T
- Subjects
- Alginates chemistry, Amino Acid Sequence, Chromatography, Thin Layer, Cloning, Molecular, Comamonadaceae chemistry, Comamonadaceae genetics, Comamonadaceae metabolism, Escherichia coli metabolism, Hydrogen-Ion Concentration, Mass Spectrometry, Polymers chemistry, Polymers metabolism, Polysaccharide-Lyases chemistry, Polysaccharide-Lyases genetics, Sequence Alignment, Substrate Specificity, Temperature, Trisaccharides metabolism, Alginates metabolism, Comamonadaceae enzymology, Polysaccharide-Lyases metabolism
- Abstract
Hydrogenopahaga sp. strain UMI-18 is an alginolytic bacterium that can produce poly(3-hydroxybutylate) (PHB) using alginate as its sole carbon source. Genome analysis indicated that this strain harbors both PHB-synthesizing and alginate-assimilating gene clusters. In the present study, we cloned HyAly-I gene that encodes a PL-17 exolytic alginate lyase and investigated its enzymatic properties using recombinant HyAly-I (recHyAly-I) that was produced by Escherichia coli. The recHyAly-I preferably depolymerized poly(β-D-mannuronate) block of alginate in an exolytic manner at an optimal temperature and a pH at 40 °C and pH 6.0, respectively. It released 4-deoxy-L-erythro-5-hexoseulose uronic acid (DEH) from the non-reducing terminus of polymer and oligomer substrates. Interestingly, recHyAly-I was found to produce a novel unsaturated disaccharide, i.e., dimeric DEH (diDEH), along with monomeric DEH. Production of diDEH was prominent in the degradation of trisaccharides., Competing Interests: Declaration of competing interest The authors declare no conflict of interest., (Copyright © 2020 Elsevier Inc. All rights reserved.)
- Published
- 2020
- Full Text
- View/download PDF
5. Minor contribution of HLA class I-associated selective pressure to the variability of HIV-1 accessory protein Vpu.
- Author
-
Hasan Z, Carlson JM, Gatanaga H, Le AQ, Brumme CJ, Oka S, Brumme ZL, and Ueno T
- Subjects
- Amino Acid Sequence, Amino Acid Substitution, Base Sequence, Codon genetics, HIV Infections virology, HIV-1 immunology, Human Immunodeficiency Virus Proteins immunology, Humans, Molecular Sequence Data, Polymorphism, Genetic, Viral Regulatory and Accessory Proteins immunology, HIV Infections immunology, HIV-1 genetics, Histocompatibility Antigens Class I immunology, Human Immunodeficiency Virus Proteins genetics, Selection, Genetic, Viral Regulatory and Accessory Proteins genetics
- Abstract
Host HLA class I (HLA-I) allele-associated immune responses are major forces driving the evolution of HIV-1 proteins such as Gag and Nef. The viral protein U (Vpu) is an HIV-1 accessory protein responsible for CD4 degradation and enhancement of virion release by antagonizing tetherin/CD317. Although Vpu represents one of the most variable proteins in the HIV-1 proteome, it is still not clear to what extent HLA-I influence its evolution. To examine this issue, we enrolled 240 HLA-I-typed, treatment naïve, chronically HIV-infected subjects in Japan, and analyzed plasma HIV RNA nucleotide sequences of the vpu region. Using a phylogenetically-informed method incorporating corrections for HIV codon covariation and linkage disequilibrium among HLA alleles, we investigated HLA-associated amino acid mutations in the Vpu protein as well as in the translational products encoded by alternative reading frames. Despite substantial amino acid variability in Vpu, we identified only 4 HLA-associations in all possible translational products encoded in this region, suggesting that HLA-associated immune responses had minor effects on Vpu variability in this cohort. Rather, despite its size (81 amino acids), Vpu showed 103 codon-codon covariation associations, suggesting that Vpu conformation and function are preserved through many possible combinations of primary and secondary polymorphisms. Taken together, our study suggests that Vpu has been comparably less influenced by HLA-I-associated immune-driven evolution at the population level compared to other highly variable HIV-1 accessory proteins., (Copyright © 2012 Elsevier Inc. All rights reserved.)
- Published
- 2012
- Full Text
- View/download PDF
6. Sulfation of glucuronic acid in the linkage tetrasaccharide by HNK-1 sulfotransferase is an inhibitory signal for the expression of a chondroitin sulfate chain on thrombomodulin.
- Author
-
Nakagawa N, Izumikawa T, Kitagawa H, and Oka S
- Subjects
- Animals, Carbohydrate Sequence, Cell Line, Chondroitin Sulfates chemistry, Cricetinae, Cricetulus, Humans, Molecular Sequence Data, Oligosaccharides chemistry, Sulfates, Thrombomodulin chemistry, Chondroitin Sulfates biosynthesis, Glucuronic Acid metabolism, Oligosaccharides metabolism, Sulfotransferases metabolism, Thrombomodulin metabolism
- Abstract
HNK-1 (human natural killer-1) carbohydrate epitope (HSO(3)-3GlcAβ1-3Galβ1-4GlcNAc-) recognized by a HNK-1 monoclonal antibody is highly expressed in the nervous system and biosynthesized by a glucuronyltransferase (GlcAT-P or GlcAT-S), and sulfotransferase (HNK-1ST). A similar oligosaccharide (HSO(3)-3GlcAβ1-3Galβ1-3Galβ1-4Xyl) also recognized by the HNK-1 antibody had been found in a glycosaminoglycan (GAG)-protein linkage region of α-thrombomodulin (TM) from human urine. However, which sulfotransferase is involved in sulfation of the terminal GlcA in the GAG-protein linkage region remains unclear. In this study, using CHO-K1 cells in which neither GlcAT-P nor GlcAT-S is endogenously expressed, we found that HNK-1ST has the ability to produce HNK-1 immunoreactivity on α-TM. We also demonstrated that HNK-1ST caused the suppression of chondroitin sulfate (CS) synthesis on TM and a reduction of its anti-coagulant activity. Moreover, using an in vitro enzyme assay system, the HNK-1-positive TM was found not to be utilized as a substrate for CS-polymerizing enzymes (chondroitin synthase (ChSy) and chondroitin polymerizing factor (ChPF)). These results suggest that HNK-1ST is involved in 3-O-sulfation of the terminal GlcA of the linkage tetrasaccharide which acts as an inhibitory signal for the initiation of CS biosynthesis on TM., (Copyright © 2011 Elsevier Inc. All rights reserved.)
- Published
- 2011
- Full Text
- View/download PDF
7. Naturally arising HIV-1 Nef variants conferring escape from cytotoxic T lymphocytes influence viral entry co-receptor expression and susceptibility to superinfection.
- Author
-
Mwimanzi P, Hasan Z, Tokunaga M, Gatanaga H, Oka S, and Ueno T
- Subjects
- AIDS Vaccines immunology, Amino Acid Substitution, DNA Mutational Analysis, Down-Regulation, HIV-1 genetics, HLA-B Antigens immunology, HLA-B35 Antigen, Humans, Mutation, Receptors, CCR5 immunology, Receptors, CXCR4 immunology, Superinfection virology, T-Lymphocytes, Cytotoxic virology, nef Gene Products, Human Immunodeficiency Virus genetics, HIV-1 immunology, Superinfection immunology, T-Lymphocytes, Cytotoxic immunology, Virus Internalization, nef Gene Products, Human Immunodeficiency Virus immunology
- Abstract
HIV-1 Nef is a key factor for pathogenesis and is known to down-regulate functionally important molecules, including viral entry co-receptor CCR5 and CXCR4, from the surface of HIV-infected cells. Some of these Nef activities are mediated by the well-conserved proline-rich region of Nef, and this region is highly targeted by cytotoxic T lymphocytes (CTLs). In the present study, we asked whether Nef variants selected under CTL-mediated selective pressure in vivo may constrain these important Nef activities. The analysis of autologous nef sequences isolated from a cohort of total 235 subjects in Japan revealed that the subjects showing amino acid variations, such as Arg75Thr and Tyr85Phe, located within the proline-rich region were significantly over-represented by those having HLA-B*3501. CTL assays corroborated that these mutations conferred escape from HLA-B(∗)3501-restricted CTLs. The Arg75Thr variant Nef selectively impaired CCR5, but not CXCR4, down-regulation activity from the cell surface; whereas the Tyr85Phe variant Nef affected neither CCR5 nor CXCR4 down-regulation activity. Moreover, the cells expressing the Arg75Thr variant Nef significantly impaired protection from superinfection by CCR5-tropic, but not CXCR4-tropic, viruses. These results highlighted the importance of certain Nef-specific CTLs in modulation of viral co-receptor down-regulation activity and protection from HIV-1 superinfection, providing us with additional insight into vaccine design., (Copyright © 2010 Elsevier Inc. All rights reserved.)
- Published
- 2010
- Full Text
- View/download PDF
8. GPR35 is a novel lysophosphatidic acid receptor.
- Author
-
Oka S, Ota R, Shima M, Yamashita A, and Sugiura T
- Subjects
- Adenosine pharmacology, Calcium metabolism, Cannabinoid Receptor Agonists, Cell Line, Extracellular Signal-Regulated MAP Kinases metabolism, Humans, Kynurenic Acid pharmacology, Ligands, Lysophospholipids pharmacology, Purinones pharmacology, Receptors, Cannabinoid metabolism, Receptors, G-Protein-Coupled agonists, Receptors, G-Protein-Coupled genetics, Receptors, Lysophosphatidic Acid agonists, Receptors, Lysophosphatidic Acid genetics, rhoA GTP-Binding Protein metabolism, Lysophospholipids metabolism, Receptors, G-Protein-Coupled metabolism, Receptors, Lysophosphatidic Acid metabolism
- Abstract
GPR35 is a rhodopsin-like G protein-coupled receptor identified in 1998. It has been reported that kynurenic acid, a tryptophan metabolite, may act as an endogenous ligand for GPR35. However, the concentrations of kynurenic acid required to elicit the cellular responses are usually high, raising the possibility that another endogenous ligand may exist. In this study, we searched for another endogenous ligand for GPR35. Finally, we found that the magnitude of the Ca(2+) response induced by 2-acyl lysophosphatidic acid in the GPR35-expressing HEK293 cells was markedly greater than that in the vector-transfected control cells. Such a difference was not apparent in the case of 1-acyl lysophosphatidic acid. 2-Acyl lysophosphatidic acid also caused the sustained activation of RhoA and the phosphorylation of extracellular signal-regulated kinase, and triggered the internalization of the GPR35 molecule. These results strongly suggest that 2-acyl lysophosphatidic acid is an endogenous ligand for GPR35.
- Published
- 2010
- Full Text
- View/download PDF
9. Different immunodominance of HIV-1-specific CTL epitopes among three subtypes of HLA-A*26 associated with slow progression to AIDS.
- Author
-
Kawashima Y, Satoh M, Oka S, Shirasaka T, and Takiguchi M
- Subjects
- Cells, Cultured, Disease Progression, Humans, Acquired Immunodeficiency Syndrome immunology, HIV-1 immunology, HLA-A Antigens immunology, Immunodominant Epitopes immunology, T-Lymphocytes, Cytotoxic immunology
- Abstract
It is speculated that HLA-A( *)26-restricted HIV-1-specific CTLs can control HIV-1, since HLA-A( *)26 is associated with a slow progression to AIDS. In three major HLA-A( *)26 subtypes, HLA-A( *)2601-restricted, and HLA-A( *)2603-restricted HIV-1 epitopes have been identified, but HLA-A( *)2602-restricted ones have not. We here identified HLA-A( *)2602-restricted HIV-1 epitopes by using reverse immunogenetics and compared the immunodominance of the epitopes among the three subtypes. Out of 110 HIV-1 peptides carrying HLA-A( *)26 anchor residues, only the Gag169-177 peptide, which had been previously identified as an HLA-A( *)2601- and HLA-A( *)2603-restricted immunodominant epitope, induced Gag169-177-specific CD8(+) T cells from only two of six HLA-A( *)2602(+) HIV-1-infected individuals. No difference in affinity of this epitope peptide was found among these three HLA-A( *)26 subtypes, indicating that Gag169-177 was effectively presented by HLA-A( *)2602 but recognized as a subdominant epitope in HIV-1-infected HLA-A( *)2602(+) individuals. These findings indicate different immunodominance of Gag169-177 epitope among 3 HLA-A( *)26 subtypes.
- Published
- 2008
- Full Text
- View/download PDF
10. Identification of GPR55 as a lysophosphatidylinositol receptor.
- Author
-
Oka S, Nakajima K, Yamashita A, Kishimoto S, and Sugiura T
- Subjects
- Binding Sites, Cell Line, Humans, Protein Binding, Receptors, Cannabinoid, Kidney metabolism, Receptors, G-Protein-Coupled chemistry, Receptors, G-Protein-Coupled metabolism, Receptors, Lysophospholipid chemistry, Receptors, Lysophospholipid metabolism
- Abstract
GPR55 is an orphan G protein-coupled receptor. In this study, we explored a possible endogenous ligand for GPR55 using HEK293 cells which expressed GPR55. We found that lysophosphatidylinositol induced rapid phosphorylation of the extracellular signal-regulated kinase in transiently or stably GPR55-expressing cells. On the other hand, lysophosphatidylinositol did not induce phosphorylation of the extracellular signal-regulated kinase in vector-transfected cells. Lysophosphatidic acid and sphingosine 1-phosphate also induced phosphorylation of the extracellular signal-regulated kinase in GPR55-expressing cells. However, these lipid phosphoric acids elicited similar responses in vector-transfected cells. Various types of other lysolipids as well as the cannabinoid receptor ligands did not induce phosphorylation of the extracellular signal-regulated kinase. We also found that lysophosphatidylinositol elicited a rapid Ca2+ transient in GPR55-expressing cells. Lysophosphatidylinositol also stimulated the binding of GTPgammaS to the GPR55-expressing cell membranes. These results strongly suggest that GPR55 is a specific and functional receptor for lysophosphatidylinositol.
- Published
- 2007
- Full Text
- View/download PDF
11. Live imaging of spindle pole disorganization in docetaxel-treated multicolor cells.
- Author
-
Sakaushi S, Nishida K, Minamikawa H, Fukada T, Oka S, and Sugimoto K
- Subjects
- Aurora Kinases, Cell Division, Cell Line, Tumor, Centrosome physiology, Docetaxel, Dose-Response Relationship, Drug, Green Fluorescent Proteins genetics, Green Fluorescent Proteins metabolism, Humans, Interphase, Protein Serine-Threonine Kinases genetics, Protein Serine-Threonine Kinases metabolism, Spindle Apparatus physiology, Time Factors, Antineoplastic Agents pharmacology, Centrosome drug effects, Microscopy, Fluorescence methods, Spindle Apparatus drug effects, Taxoids pharmacology
- Abstract
Treatment of cells with docetaxel at low concentrations induces aberrant bipolar spindles of which two centrosomes stay at only one pole, and also induces multipolar spindles. To gain insight into the relations between centrosome impairment and structural defects of the spindle, live-cell imaging was performed on a human MDA Auro/imp/H3 cell line in which centrosomes/mitotic spindles, nuclear membrane and chromatin were simultaneously visualized by fluorescent proteins. In the presence of docetaxel at IC(50) concentration, the centrosomes did not segregate, and multiple aster-like structures ectopically arose around the disappearing nuclear membrane. Those ectopic structures formed an acentrosomal pole opposing to the two-centrosomes-containing pole. In late metaphase, one pole often fragmented into multiple spindle poles, leading multipolar division. These results suggest that spindle pole fragility may be induced by centrosome impairment, and collapse of the pole may contribute to induction of aneuploid daughter cells.
- Published
- 2007
- Full Text
- View/download PDF
12. Differential gene dosage effects of Ad4BP/SF-1 on target tissue development.
- Author
-
Fatchiyah, Zubair M, Shima Y, Oka S, Ishihara S, Fukui-Katoh Y, and Morohashi K
- Subjects
- Animals, Gene Dosage, Mice, Mice, Knockout, Spleen growth & development, Steroidogenic Factor 1, Transgenes physiology, Adrenal Glands growth & development, Gonads growth & development, Homeodomain Proteins genetics, Hypothalamo-Hypophyseal System growth & development, Receptors, Cytoplasmic and Nuclear genetics, Transcription Factors genetics
- Abstract
Ad4BP/SF-1 (NR5A1) was identified as a key regulator of the hypothalamus-pituitary-gonadal and -adrenal axes. Loss-of-function studies revealed that Ad4BP/SF-1 is essential for the development of these tissues and spleen. Here, we generated transgenic mouse with BAC recombinants carrying a dual promoter and Tet-off system. These recombinants have a potential to express lacZ and Ad4BP/SF-1 in the tissues where endogenous Ad4BP/SF-1 is expressed. However, protein level of Ad4BP/SF-1 varied among the tissues of the transgenic mice and probably thereby the target tissues are affected differentially. The BAC-transgenic mice were applied to rescue Ad4BP/SF-1 KO mouse. Interestingly, the mice successfully rescued the gonad and spleen but failed to rescue the adrenal gland. This variation might be dependent on in part the protein expression levels among the tissues and in part on differential sensitivities to the gene dosage.
- Published
- 2006
- Full Text
- View/download PDF
13. Homozygous CYP2B6 *6 (Q172H and K262R) correlates with high plasma efavirenz concentrations in HIV-1 patients treated with standard efavirenz-containing regimens.
- Author
-
Tsuchiya K, Gatanaga H, Tachikawa N, Teruya K, Kikuchi Y, Yoshino M, Kuwahara T, Shirasaka T, Kimura S, and Oka S
- Subjects
- Alkynes, Benzoxazines, Cyclopropanes, Cytochrome P-450 CYP2B6, Gene Frequency, Genotype, Reverse Transcriptase Inhibitors blood, Statistics as Topic, Anti-HIV Agents blood, Aryl Hydrocarbon Hydroxylases genetics, HIV Infections blood, HIV Infections drug therapy, HIV Infections genetics, HIV-1, Oxazines blood, Oxidoreductases, N-Demethylating genetics, Polymorphism, Genetic
- Abstract
Efavirenz (EFV) is metabolized by cytochrome P450 2B6 (CYP2B6) in the liver. We analyzed the genotypes of CYP2B6 and their contribution to plasma EFV concentrations in 35 EFV-treated patients in International Medical Center of Japan. The mean plasma EFV concentration of patients with CYP2B6 *6/*6 (Q172H and K262R) (25.4+/-7.5 microM, +/-SD, n = 2) was significantly higher than that of patients with genotypes *6 heterozygote (9.9+/-3.3 microM, n = 10) or without alleles *6 (8.0+/-2.6 microM, n = 23) (p < 0.0001). To confirm our result, we further analyzed nine patients (three with high EFV concentrations and arbitrarily selected six with normal EFV concentrations) treated in Osaka National Hospital, and it resulted that the only three patients with the high concentrations were the *6/*6 holder. EFV dose could be decreased in those patients harboring the genotype to reduce toxicity with compromising potency, representing the first step of the Tailor-Made therapy of HIV-1 infection.
- Published
- 2004
- Full Text
- View/download PDF
14. Expression of macrophage asialoglycoprotein-binding protein is induced through MAPK classical pathway.
- Author
-
Katsuyama R, Morioka A, Oka S, and Kawasaki T
- Subjects
- Animals, Blotting, Western, Enzyme Inhibitors pharmacology, Flavonoids pharmacology, Gene Expression Regulation drug effects, Humans, Imidazoles pharmacology, Macrophages drug effects, Mitogen-Activated Protein Kinases antagonists & inhibitors, Mitogen-Activated Protein Kinases metabolism, Naphthalenes pharmacology, Protein Kinase C antagonists & inhibitors, Pyridines pharmacology, RNA, Messenger drug effects, RNA, Messenger genetics, RNA, Messenger metabolism, Rats, Staurosporine pharmacology, Tetradecanoylphorbol Acetate pharmacology, U937 Cells, p38 Mitogen-Activated Protein Kinases, Carrier Proteins genetics, Lectins, MAP Kinase Signaling System physiology, Macrophages metabolism, Receptors, Cell Surface
- Abstract
Macrophage asialoglycoprotein-binding protein (M-ASGP-BP) is a Gal/GalNAc-specific lectin, which functions as an endocytosis receptor. We found that the expression of M-ASGP-BP mRNA in bone marrow cells was induced during the differentiation into macrophages. To investigate the mechanism by which M-ASGP-BP mRNA expression is induced, we used U937 cells as a model. Treatment of U937 cells with 12-O-tetradecanoylphorbol-13-acetate (TPA) resulted in M-ASGP-BP mRNA expression within 6 h. This induction was completely inhibited by PKC inhibitors, calphostin C, and staurosporine. Furthermore, MAP kinase inhibitors PD98059, but not SB202190, blocked M-ASGP-BP mRNA expression. These data indicate that M-ASGP-BP mRNA expression occurs through the activation of PKC and the MAPK classical pathway in the course of cell differentiation into macrophages.
- Published
- 2001
- Full Text
- View/download PDF
15. Involvement of nitric oxide in endothelium-dependent arterial relaxation by leptin.
- Author
-
Kimura K, Tsuda K, Baba A, Kawabe T, Boh-oka S, Ibata M, Moriwaki C, Hano T, and Nishio I
- Subjects
- Acetylcholine pharmacology, Animals, Arginine pharmacology, Chlorides metabolism, Humans, In Vitro Techniques, Indomethacin pharmacology, Leptin physiology, Male, NG-Nitroarginine Methyl Ester pharmacology, Potassium Channel Blockers, Rats, Rats, Wistar, Endothelium, Vascular drug effects, Endothelium, Vascular physiology, Leptin pharmacology, Nitric Oxide physiology, Vasodilation drug effects, Vasodilation physiology
- Abstract
Leptin is a polypeptide, mainly produced in white adipose tissue, and increases sympathetic nerve activity. A few studies investigated leptin's effect on peripheral vessels. We examined the vasorelaxant effects of human leptin on rat arteries. Arterial rings were precontracted with 1 x 10(-6) mol/l of phenylephrine, and leptin was superfused. Leptin relaxed phenylephrine-precontracted arterial rings in a dose-dependent manner. ED50 was calculated to 8.4 microg/ml. Removal of endothelium abolished the effects of leptin. Indomethacin (1 x 10(-5) mol/l) did not affect the vasorelaxation by leptin, whereas 1 x 10(-4) mol/l of N(omega)-nitro-L-arginine methyl ester (L-NAME) completely suppressed it. The inhibition was antagonized by 1 x 10(-4) mol/l of L-arginine. Leptin normally relaxed arterial rings during superfusion of K channel blockers, including 3 x 10(-5) mol/l of glibenclamide, 1 x 10(-6) of mol/l apamin, and 5 x 10(-7) mol/l of charybdotoxin. Low Cl(-) solution (8. 3 mmol/l) inhibited leptin-induced relaxation, but endothelium-independent vasodilatation by nitroprusside was not impaired at low Cl(-) solution. These results suggest that arterial relaxation by leptin is mediated by nitric oxide released from endothelium, and Cl(-) plays an important role in leptin-induced nitric oxide release., (Copyright 2000 Academic Press.)
- Published
- 2000
- Full Text
- View/download PDF
16. Molecular cloning and expression of a second glucuronyltransferase involved in the biosynthesis of the HNK-1 carbohydrate epitope.
- Author
-
Seiki T, Oka S, Terayama K, Imiya K, and Kawasaki T
- Subjects
- Amino Acid Sequence, Animals, Base Sequence, Brain, Cloning, Molecular, DNA, Complementary isolation & purification, Molecular Sequence Data, Rats, CD57 Antigens genetics, DNA, Complementary genetics, Glucuronosyltransferase genetics
- Abstract
A cDNA encoding a novel glucuronyltransferase was cloned from a rat brain cDNA library. The cDNA sequence contained an open reading frame encoding 324 amino acids, with type II transmembrane topology. The amino acid sequence revealed 49% homology to rat GlcAT-P, a glucuronyltransferase involved in the biosynthesis of the HNK-1 carbohydrate epitope of glycoproteins, [Terayama et al. (1997) Proc. Natl. Acad. Sci. USA 94, 6093-6098] and the highest sequence homology was found in the catalytic region. Northern blot analysis indicated that this newly cloned glucuronyltransferase is expressed in the nervous system, consistent with the selective localization of the HNK-1 carbohydrate epitope in the nervous system. Transfection of this cDNA into COS-1 cells induced the expression of the HNK-1 carbohydrate epitope on cell surfaces, and induced the morphological changes in these cells. These results indicated that this newly cloned cDNA is a second glucuronyltransferase involved in the biosynthesis of the HNK-1 carbohydrate epitope., (Copyright 1999 Academic Press.)
- Published
- 1999
- Full Text
- View/download PDF
17. Overexpression of MP41 gene in a transformed endothelial cell line correlates with the increased fibronectin expression and a decreased incidence of tumorigenicity.
- Author
-
Kondo M, Watanabe M, Amanuma K, Oka S, and Ishida N
- Subjects
- Animals, Cell Division, Cell Line, Cell Line, Transformed, Cell Movement, Circadian Rhythm, Endothelium, Vascular metabolism, Gene Expression, Humans, Kinetics, Mice, Mice, Nude, Protein Biosynthesis, RNA, Messenger biosynthesis, RNA, Messenger metabolism, Recombinant Proteins biosynthesis, Recombinant Proteins metabolism, Time Factors, Transfection, Transplantation, Heterologous, Cell Transformation, Neoplastic, Fibronectins biosynthesis, Neoplasms, Experimental pathology, Proteins physiology
- Abstract
mp41 gene, which was originally identified as a gene regulated by the circadian clock, showed some similarity with yeast cell cycle regulator, CDC25, and its mRNA expression is restricted mainly to non-dividing cell. To elucidate the growth regulatory of mp41, mp41 cDNA was transfected into a transformed human endothelial cell line. All stable mp41 transformants showed increased levels of fibronectin expression and reduced migratory activity in vitro. Although the in vitro growth rate of mp41 transformants and their ability to grow in soft agar were not significantly altered, their tumor formation was suppressed significantly in nude mice. The results imply that mp41 gene overexpression altered the tumorigenicity associated with fibronectin elevation in stable transformation of the transformed endothelial cell line.
- Published
- 1996
- Full Text
- View/download PDF
18. Endotoxin antagonism by a synthetic lipid A analogue, DT-5461, with low endotoxicity in human peripheral blood monocytes.
- Author
-
Sato K, Fujihara M, Takahashi TA, Choon Yoo Y, Hata K, Tono-Oka S, Suzuki T, Sekiguchi S, and Azuma I
- Subjects
- Adjuvants, Immunologic pharmacology, Binding, Competitive, Cells, Cultured, Culture Media, Culture Media, Serum-Free, Disaccharides metabolism, Dose-Response Relationship, Drug, Endotoxins antagonists & inhibitors, Escherichia coli, Humans, Interleukin-1 biosynthesis, Interleukin-1 blood, Kinetics, Lipid A metabolism, Lipid A pharmacology, Lipopolysaccharides antagonists & inhibitors, Monocytes drug effects, Tumor Necrosis Factor-alpha biosynthesis, Disaccharides pharmacology, Endotoxins pharmacology, Lipid A analogs & derivatives, Lipopolysaccharides pharmacology, Monocytes immunology
- Abstract
We examined the molecular mechanism of DT-5461-induced LPS antagonism in human peripheral blood monocytes. Dose-response studies revealed that LPS-induced IL-1 and TNF-alpha production was apparently totally suppressed in a competitive manner by a 10-fold excess of DT-5461. A 10-fold excess of DT-5461 significantly blocked the binding of FITC-LPS to the monocytes. DT-5461 suppressed IL-1 and TNF-alpha mRNA expression in LPS-activated monocytes. Western blots showed that DT-5461 suppressed the LPS-induced tyrosine phosphorylation of p42mapk/ERK2. These results suggested that the competitive binding inhibition and repression of early intracellular signaling involved in DT-5461-mediated LPS antagonism.
- Published
- 1995
- Full Text
- View/download PDF
19. Cytochrome P-450-butyl peroxide complex detected by ESR.
- Author
-
Tajima K, Edo T, Ishizu K, Imaoka S, Funae Y, Oka S, and Sakurai H
- Subjects
- Animals, Cytochrome P-450 Enzyme System isolation & purification, Electron Spin Resonance Spectroscopy methods, Kinetics, Oxidants metabolism, Protein Binding, Rats, Spin Labels, tert-Butylhydroperoxide, Cytochrome P-450 Enzyme System metabolism, Microsomes, Liver enzymology, Peroxides metabolism
- Abstract
ESR measurements were performed for the reaction systems composed of t- or n-butylhydroperoxide and cytochrome P-450 (UT-2), purified from rat liver microsomes. On addition of n-butylhydroperoxide to the P-450 at pH 7.4, ESR signal due to a ferric low-spin species (g1 = 2.29, g2 = 2.24 and g3 = 1.96) was recorded. The observed g-parameters agreed well with those of a model thiolate-heme-iron(III)-peroxide complex, Fe(III)TPP(-S-TGE) (-OO-t-butyl) (g1 = 2.285, g2 = 2.198 and g3 = 1.959). In terms of the g-parameters, the new P-450 complex was concluded to be a P-450-butyl peroxide adduct, in which a butyl peroxide anion ligates at the sixth position of heme iron(III).
- Published
- 1993
- Full Text
- View/download PDF
20. Quantitative analysis of human immunodeficiency virus type-1 DNA in asymptomatic carriers using the polymerase chain reaction.
- Author
-
Oka S, Urayama K, Hirabayashi Y, Ohnishi K, Goto H, Mitamura K, Kimura S, and Shimada K
- Subjects
- Autoradiography, Electrophoresis, Polyacrylamide Gel, Female, Humans, Lymphocytes microbiology, Male, Polymerase Chain Reaction, DNA, Viral analysis, HIV Seropositivity genetics, HIV-1 genetics
- Abstract
A method for detecting human immunodeficiency virus type 1 (HIV-1) provirus DNA in lymphocytes with improved sensitivity and reproducibility was developed using the polymerase chain reaction (PCR). Amplified HIV-1 DNA was hybridized with a 32P-labeled probe and quantitated with a beta-scanner after electrophoresis. A linear relationship was obtained between the common logarithms of the counts detected and the number of HIV-1 DNA copies applied to the PCR. Detectability was from 3 copies/10(5) lymphocytes, and linearity was maintained from 10 to 10(3) copies. HIV-1 DNA was detected in all 9 asymptomatic carriers tested (18 to 2,857 copies/10(5) CD4+ T lymphocytes). The viral burden was inversely related to the CD4+ lymphocyte count, suggesting that quantitation of provirus levels may serve as a predictor of progress in early HIV infection.
- Published
- 1990
- Full Text
- View/download PDF
21. E-series prostaglandins activate cAMP-mediated potassium currents in follicle-enclosed Xenopus oocyte.
- Author
-
Mori K, Oka S, Tani A, Ito S, and Watanabe Y
- Subjects
- Acetylcholine pharmacology, Animals, Colforsin pharmacology, Cyclic AMP physiology, Electric Conductivity, Female, Membrane Potentials drug effects, Receptors, Prostaglandin E, Theophylline pharmacology, Xenopus laevis, Oocytes physiology, Ovary physiology, Potassium physiology, Potassium Channels physiology, Prostaglandins E pharmacology, Receptors, Prostaglandin physiology
- Abstract
Receptor-mediated responses to prostaglandins E1 and E2 are shown by electrophysiological methods in follicle-enclosed oocytes of Xenopus laevis. In voltage-clamped oocytes, prostaglandins E1 and E2 elicited an outward hyperpolarizing current. This outward membrane current was caused by an increase in K+ conductance. The prostaglandin-induced current was augmented by adenylate cyclase activator, forskolin, and by phosphodiesterase inhibitor, theophylline, indicating that adenosine 3', 5'-cyclic monophosphate (cAMP) is involved in activating the K+ current. The prostaglandin responses were either abolished or greatly reduced by removing follicular cells with collagenase, suggesting that prostaglandin receptors reside in the follicular cells.
- Published
- 1989
- Full Text
- View/download PDF
22. Purification of erythropoiesis-stimulating activity (ESA) from one Actinomycetes strain.
- Author
-
Sugie M, Oka S, and Tanaka H
- Subjects
- Animals, Bone Marrow Cells, Chromatography, DEAE-Cellulose, Electrophoresis, Polyacrylamide Gel, Male, Mice, Molecular Weight, Actinomycetaceae metabolism, Erythropoiesis, Glycoproteins isolation & purification, Lymphokines isolation & purification
- Abstract
An Actinomycetes strain was found to produce a protein which stimulated the growth of murine erythroid progenitors in vitro. The protein was purified to homogeneity and was named Erythropoiesis-Stimulating Activity (ESA). ESA was an acidic glycoprotein with a molecular weight around 80,000. When mouse bone marrow cells were cultured in methylcellulose medium containing physiological concentrations of erythropoietin (0.048 units/ml), addition of ESA stimulated the growth of colony forming unit-erythroid (CFU-E) up to three-fold a in dose dependent manner. ESA was not active on the other hematopoietic progenitors.
- Published
- 1989
- Full Text
- View/download PDF
23. Effects of okadaic acid on mouse hemopoietic cells.
- Author
-
Oka S, Nakagomi K, Tanaka H, and Yasumoto T
- Subjects
- Animals, B-Lymphocytes cytology, B-Lymphocytes drug effects, Cells, Cultured, Colony-Forming Units Assay, Colony-Stimulating Factors biosynthesis, Hematopoietic Stem Cells drug effects, Kinetics, Macrophages cytology, Macrophages drug effects, Male, Mice, Mice, Inbred ICR, Okadaic Acid, Spleen immunology, T-Lymphocytes cytology, T-Lymphocytes drug effects, Carcinogens pharmacology, Ethers, Cyclic pharmacology, Hematopoietic Stem Cells cytology
- Abstract
Effects of okadaic acid, a potent non-12-O-tetradecanoyl-phorbol-13-acetate(TPA)-type tumor promoter, on mouse hemopoietic cells were investigated. Okadaic acid stimulated mouse bone marrow cells to form granulocyte-macrophage colony-forming unit (CFU-GM) colonies without added colony stimulating factors(CSFs). At the concentration of 1.82 x 10(-8) M, colony formation of 77 +/- 14 colonies/1 x 10(5) bone marrow cells was observed. Observations on the effects of other cells on the CSF induction suggested that okadaic acid primarily stimulated the functions of macrophages, and the CSF production from macrophages might be attributed to the CFU-GM colony formation. On the other hand, the erythroid colony-forming unit(CFU-E) colony formation stimulated by
- Published
- 1989
- Full Text
- View/download PDF
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.