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Biomedical subjects

T Miyake

Publications and source records attributed to T Miyake.

At least 469 records · Page 26Linked to original sources
PubMed1979

A new method for 3'-labelling of polyribonucleotides by phosphorylation with RNA ligase and its application to the 3'-modification for joining reactions.

P1-Adenosine 5'-P2-o-nitrobenzyl pyrophosphate (nbzlppA) has been synthesized as a substrate for T4 RNA ligase catalyzed 3'-phosphorylation. Incubation of oligoribonucleotides and nbzlppA with RNA ligase yielded oligoribonucleotides having a 3'-o-(o-nitrobenzyl) phosphate. Photochemical removal of the o-nitrobenzyl group provided the free 3'-phosphate. Using [P2-32P] nbzlppA, 3'-termini of oligoribonucleotides could be labelled with 32P. This reaction was applied to modify the 3'-end of donor molecules in joining reaction with RNA ligase. A trinucleotide U-A-G was converted to U-A-Gpnbzl and phosphorylated with polynucleotide kinase. pU-A-Gpnbzl was then joined to an acceptor trinucleotide A-U-G to yield A-U-G-U-A-Gp.

Adenosine Diphosphate↗
PubMed1978

Joining of 3'-modified oligonucleotides by T4 RNA ligase. Synthesis of a heptadecanucleotide corresponding to the bases 61--77 from Escherichia coli tRNAfMet.

Chemically synthesized fragments corresponding to the 3' end of tRNAfMet from Escherichia coli were joined by T4-induced RNA ligase to yield a heptadecanucleotide (bases 61--77). The 3' terminus of C-C-A was modified by introduction of the ethoxymethylidene group to prevent intra- and intermolecular self-joining reactions at the 3' end. The terminal trimer was phosphorylated using polynucleotide kinase and joined to C-A-A with RNA ligase. The hexamer [C-A-A-C-C-A(ethoxymethylidene)] corresponding to bases 72--77 was obtained in a yield of 60%. An undecanucleotide (bases 61--71) which had been synthesized in a yield of 34% by similar enzymatic joining of U-C-C-G-G to pC-C-C-C-C-G was allowed to react with the 5'-phosphorylated hexamer (bases 72--77) using an excess of RNA ligase to yield the heptadecanucleotide U-C-C-G-G-C-C-C-C-C-G-C-A-A-C-C-A (bases 61--77). The product was identified by homochromatography and nearest neighbor analysis.

Base Sequence↗
PubMed1978

Cell fusion between temperature-sensitive mutants of a Drosophila melanogaster cell line.

Temperature-sensitive (ts) mutants were isolated in a cell line of Drosophila melanogaster, GM1, by ethyl methanesulfate treatment. Two of them, ts15 and ts58, formed colonies at 23 degrees C but not at 30 degrees when inoculated at densities of/or less than 10(5) cells per 60 X 15-mm dish. By using these ts mutants, cell fusion was attempted with polyethylene glycol (PEG) 6000. Several colonies per dish developed at 30 degrees C when different ts mutants were mixed, treated with PEG, and inoculated at a density of 10(4) cells per dish. Cells in some of the colonies thus developed were propagated and their temperature-sensitive character and karyotypes were studied. The results indicated that cell fusion could be induced with PEG and that the cells which formed colonies at 30 degrees C after PEG treatment were the hybrids in which the temperature-sensitive lesions in the mutants were complemented.

Cell Division↗
PubMed1978

Spontaneous regression of syngeneic transplanted tumors in rats pretreated with the antileukemia drug busulfan.

Lethal growth of a syngeneic transplanted tumor (KMT-17) was inhibited in WKA rats pretreated with the antileukemia drug busulfan. The effect of busulfan was short-lasting, and administration of the drug after tumor challenge had little effect on the lethal growth of the tumor. After spontaneous regression of the tumor in rats pretreated with busulfan, specific transplantation resistance to identical tumor was acquired. Busulfan did not exhibit its effect in rats irradiated before tumor challenge. As shown by the Winn test, spleen cells from rats immunized with inactivated tumor cells after busulfan treatment inhibited growth of admixed tumor cells more strongly than did spleen cells from rats immunized without busulfan treatment. Enhancement of immune response to tumor cells rather than tumoricidal activity by busulfan was suggested.

Animals↗
PubMed1977

[Dr. Kanji Tsuji].

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Endocrinology↗
PubMed1977

Purification of human erythropoietin.

Human erythropoietin, derived from urine of patients with aplastic anemia, has been purified to apparent homogeneity. The seven-step procedure, which included ion exchange chromatography, ethanol precipitation, gel filtration, and adsorption chromatography, yielded a preparation with a potency of 70,400 units/mg of protein in 21% yield. This represents a purification factor of 930. The purified hormone has a single electrophoretic component in polyacrylamide gels at pH 9, in the presence of sodium dodecylsulfate at pH 7, and in the presence of Triton X-100 at pH 6. Two fractions of the same potency and molecular size, by sodium dodecyl sulfate gel electrophoresis, but differing slightly in mobility at pH 9, were obtained at the last step of fractionation. The nature of the difference between these two components is not yet understood.

Anemia, Aplastic↗