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Biomedical subjects

K Tanabe

Publications and source records attributed to K Tanabe.

At least 559 records · Page 31Linked to original sources
PubMed1982

Chick embryo DNA polymerase alpha. Polypeptide components and their microheterogeneity.

DNA polymerase alpha was purified from a chick embryo extract by ammonium sulfate fractionation and successive column chromatographies. The final preparation had a specific enzyme activity of 39,000 units/mg of protein with activated calf thymus DNA as a template.primer. Electrophoresis in nondenaturing polyacrylamide gel showed that the preparation contained two proteins, one of which was associated with DNA polymerase activity. On sodium dodecyl sulfate-polyacrylamide gel electrophoresis, the electrophoretically pure enzyme gave two clusters of polypeptide bands. One was composed of 3-4 polypeptides with similar electrophoretic mobilities corresponding to Mr = 130,000-155,000, and the other consisted of four distinct polypeptide bands corresponding to Mr = 59,000, 56,000, 54,000, and 51,000. Two-dimensional tryptic peptide mapping analysis of these polypeptides after 125I-iodination indicated that the structures of all four Mr = 51,000-59,000 polypeptides were very similar. In addition, polypeptides in the Mr = 145,000-155,000 region had almost identical structure with those in the Mr = 130,000-140,000 region. No significant structural homology was observed between the high molecular weight polypeptides and low molecular weight polypeptides. These findings indicate that the four polypeptides of Mr = 51,000-59,000 are generated by minor modification(s) of a single polypeptide. Similarly, the heterogeneity of the high molecular weight polypeptides is brought about by minor modification(s). Thus, chick embryo DNA polymerase alpha is basically composed of two kinds of subunit polypeptides.

Animals↗
PubMed1982

An increase in Sendai virus-induced cell fusion of erythrocytes infected with Plasmodium chabaudi.

The extent of cell fusion induced by Sendai virus was examined in erythrocytes infected with Plasmodium chabaudi. An increase in cell fusion of erythrocytes with Ehrlich tumor cells and of erythrocytes with erythrocytes was observed with the infected erythrocytes. However, agglutination by the virus was not changed between erythrocytes of normal and malarial mice. These results indicate that the increase in cell fusion occurred in the process of membrane fusion, suggesting that some membrane property of Plasmodium-parasitized erythrocytes is changed in terms of Sendai virus-induced cell fusion.

Animals↗
PubMed1982

Calcium transport of Plasmodium chabaudi-infected erythrocytes.

The calcium content and transport processes of Plasmodium chabaudi-infected rat erythrocytes were analyzed by atomic absorption spectroscopy and 45Ca2+ flux measurements. Infected erythrocytes, after fractionation on metrizamide gradients according to stage of parasite development, exhibited progressively increasing levels of Ca2+ with schizont and gametocytes containing 10- to 20-fold greater calcium levels than normal cells (0.54 +/- 0.25 nmol/10(8) cells). 45Ca2+ flux experiments showed both increased influx and decreased efflux in infected erythrocytes. Tris/NH4Cl lysis of normal erythrocytes preloaded with 45Ca2+ with the Ca2+ ionophore A23187 released less than 90% of cell calcium after incubation in ethyleneglycol bis(aminoethylether) N,N'-tetraacetic acid containing buffer, whereas lysis of the infected erythrocyte membrane resulted in release of 10-20% cell Ca2+, with the remaining portion associated with the isolated parasite fraction. This information together with the effects of various metabolic inhibitors indicates the presence of a parasite Ca2+ compartment in P. chabaudi-infected erythrocytes. Dicyclohexylcarbodiimide (DCCD) an inhibitor of proton ATPases of chloroplasts, bacteria, yeast, and mitochondria, and the proton ionophore, carbonyl cyanide m-chlorophenylhydrazone (CCCP), inhibited Ca2+ influx and stimulated efflux from infected cells. These results combined with evidence for a DCCD- and CCCP-sensitive membrane potential in P. chabaudi-infected cells (Mikkelsen et al., accompanying manuscript) suggest that Ca2+ transport of intraerythrocytic parasites is coupled to a proton-motive force across the Plasmodia plasma membrane.

Animals↗
PubMed1982

Membrane potential of Plasmodium-infected erythrocytes.

The membrane potential (Em) of normal and Plasmodium chabaudi-infected rat erythrocytes was determined from the transmembrane distributions of the lipophilic anion, thiocyanate (SCN), and cation, triphenylmethylphosphonium (TPMP). The SCN- and TPMP-measured Em of normal erythrocytes are -6.5 +/- 3 mV and -10 +/- 4 mV, respectively. The TPMP-measured Em of infected cells depended on parasite developmental stage; "late" stages (schizonts and gametocytes) were characterized by a Em = -35 mV "early stages (ring and copurifying noninfected) by a low Em (-16 mV). The SCN-determined Em of infected cells was -7 mV regardless of parasite stage. Studies with different metabolic inhibitors including antimycin A, a proton ionophore (carbonylcyanide m-chlorophenylhydrazone [CCCP] ), and a H+ -ATPase inhibitor (N,N'-dicyclohexylcarbodiimide, [DCCD] ) indicate that SCN monitors the Em across the erythrocyte membrane of infected and normal cells whereas TPMP accumulation reflects the Em across the plasma membranes of both erythrocyte and parasite. These inhibitor studies also implicated proton fluxes in Em-generation of parasitized cells. Experiments with weak acids and bases to measure intracellular pH further support this proposal. Methylamine distribution and direct pH measurement after saponin lysis of erythrocyte membranes demonstrated an acidic pH for the erythrocyte matrix of infected cells. The transmembrane distributions of weak acids (acetate and 5,5-dimethyloxazolidine-2,4-dione) indicated a DCCD-sensitive alkaline compartment. The combined results suggest that the intraerythrocyte parasite Em and delta pH are in part the consequence of an electrogenic proton pump localized to the parasite plasma membrane.

Animals↗
PubMed1982

Binding of HBs antigen to HeLa cells by use of reconstitution into liposomes and fusion by Sendai virus.

Hepatitis B surface antigen (HBsAg) was reconstituted into liposomes composed of phosphatidylserin. An isolated membrane fraction of HeLa cells was mixed with the liposomes, then the liposomes were incubated with HeLa cells in the presence of Sendai virus. In this system the attachment of HBsAg to the cell surface was enhanced and became resistant to treatment with trypsin-EDTA. The presence of the HBsAg on the cell surface was revealed by immunoelectronmicroscopy. This technique may provide a model system for studying immunological reactions to HBsAg-bearing target cells in vitro.

Antigens, Surface↗
PubMed1982

[Clinical evaluation of cefotiam in internal medicine].

Cefotiam (CTM) was administered to 52 patients with infectious disease associated with respiratory system, hematological malignancy, urinary system and other system. Good clinical responses were obtained in 38 out of 52 cases (73.1%). Neither objective and subjective side effects nor extreme abnormalities of laboratory tests were observed in these patients. It can be, therefore, concluded that CTM is 1 of the most useful drugs for infectious diseases in respiratory system, hematological malignancy, urinary system and other system.

Adolescent↗
PubMed1982

Establishment of hybridoma clones which produce anti-chick embryo DNA polymerase alpha monoclonal antibodies.

Four hybridoma clones which produce monoclonal antibodies against chick embryo DNA polymerase alpha have been established. Antibodies produced by the four clones all belonged to the gamma 1-type IgG and precipitated enzyme activity in the presence of Staphylococcus aureus cells. An affinity column prepared with one of the monoclonal antibodies (clone 6-1E) and protein A-Sepharose retained DNA polymerase alpha activity as well as the 135,000 approximately 150,000 and 50,000 approximately 60,000 dalton polypeptides of this enzyme. Thus, the antibody is specific to DNA polymerase alpha.

Animals↗
PubMed1981

[Biological and biochemical properties of human chorionic gonadotropin from urine of patients with hydatidiform mole and its radioimmunoassay (author's transl)].

Human chorionic gonadotropin (hCG) was extracted and purified from the urine of four patients with hydatidiform mole. The immunological activities of the hCG-hydatidiform mole by hCG radioimmunoassay (RIA) ranged from 9,380 to 9,700 IU/mg, and the biological activities measured by the immature rat ovarian weight method ranged from 7,250 to 7,780 IU/mg. The results of the amino acid compositions of all the hCG-hydatidiform moles were practically identical with those of hCG-normal pregnancies. The carbohydrate moiety of the hCG-hydatidiform mole was also suspected to be almost similar to that of hCG-normal pregnancies by the results of their in vitro and in vivo biological activities. It was demonstrated that hCG-hydatidiform mole was composed of alpha and beta subunits (similar to a hCG-normal pregnancy) when hCG-hydatidiform mole was separated into subunits by SDS disc electrophoresis after treatment with mercaptoethanol. The RIA system of hCG-hydatidiform mole can be established. The concentrations of hCG in sera of normal pregnant women and patients with trophoblastic diseases assayed by hCG-hydatidiform mole RIA were equivalent to those obtained by a standard hCG RIA. Hence, a standard hCG-immunoassay method used in the management of hCG is concerned.

Adult↗
PubMed1981

Identification of a polypeptide component of mouse myeloma DNA polymerase gamma.

Mouse myeloma DNA polymerase gamma was extensively purified to a final specific activity of 156 000 units (nmol dTMP incorporation per h) per mg protein on (rA)n.(dT)12-18 as a template primer. Sodium dodecyl sulfate polyacrylamide gel electrophoresis of protein fractions obtained by DNA-cellulose column chromatography revealed that the amount of a polypeptide of Mr = 47 000 changed proportionally with DNA polymerase gamma activity. A minor polypeptide of Mr = 140 000 also seemed to change with the enzyme activity, but other polypeptides did not. Analysis by 125I-labeled peptide mapping indicates that the Mr 47 000 polypeptide in the mouse myeloma DNA polymerase gamma preparation is structurally related to the Mr 47 000 polypeptide of chick embryo DNA polymerase gamma (Yamaguchi, M., Matsukage, A. and Takahashi, T. (1980) J. Biol. Chem. 255, 7002-7009). An antibody against chick embryo DNA polymerase gamma cross-reacted with the mouse enzyme, indicating a structural relationship between avian and murine enzymes. Since the Mr 47 000 polypeptide accounts for 31.4% of total protein in the purified preparation, the specific activity is estimated to be about 490 000 units per mg of the Mr 47 000 polypeptide. The rate of poly(dT) elongation by the purified enzyme was 1 260 per nucleotides per min. This value is in the same range as the turnover number (1 530 nucleotides per min per enzyme molecule) which is calculated from the 'expected' specific activity with respect to the Mr 47 000 polypeptide and the molecular weight (Mr = 188 000 on the assumption of a tetrameric structure of the Mr 47 000 polypeptide). Results indicate that the Mr 47 000 polypeptide is a component of the mouse myeloma DNA polymerase gamma.

Animals↗
PubMed1981

Terminal deoxynucleotidyltransferase of 60,000 daltons from mouse, rat, and calf thymus. Purification by immunoadsorbent chromatography and comparison of peptide structures.

For rapid simple purification of terminal deoxynucleotidyltransferase from limited amounts of tissues, we have developed an immunoadsorbent column chromatographic method using antiterminal transferase antibody-conjugated Sepharose 4B. The column specifically adsorbed all mammalian terminal deoxynucleotidyltransferase (terminal transferases) tested and, in all cases, nearly homogeneous enzymes were recovered at extremely high yields of activity and protein. By this method, we first succeeded in purifying rodent enzymes from rat or mouse thymus, which enzymes were comprised of a single polypeptide chain (Mr = 60,000). The enzyme purified from calf thymus by the same procedure showed the two well known subunits (alpha: Mr = 10,000 and beta: Mr = 32,000). However, the calf preparation purified in the presence of protease inhibitors exhibited several polypeptides with molecular weights ranging from Mr = 42,000 to Mr = 60,000, but did not contain the two-subunit form. From peptide mapping analyses, it was evident that each of the high molecular weight polypeptides contained sequences of both of the two low molecular weight subunits. These results indicate that the two subunits (alpha and beta) of the calf thymus enzyme reported earlier may be proteolytic products derived from a single polypeptide of Mr = 60,000, which may be the native form. It was noted that an extensive homology existed in primary structure of the enzymes from three species of mammals.

Animals↗