Kikuo Shimizu

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We found that a ciliated protozoan, Paramecium, swam perpendicular to a static (DC) magnetic field (0.68 T). The swimming orientation was similar even when the ionic current through the cell membrane disappeared after saponin treatment. To determine the diamagnetic anisotropy of intracellular organs, macronuclei, cilia, and secretory vesicles, trichocysts,(More)
We report that POL5 encodes the fifth essential DNA polymerase in Saccharomyces cerevisiae. Pol5p was identified and purified from yeast cell extracts and is an aphidicolin-sensitive DNA polymerase that is stimulated by yeast proliferating cell nuclear antigen (PCNA). Thus, we named Pol5p DNA polymerase phi. Temperature-sensitive pol5-1-- -3 mutants did not(More)
DNA polymerases delta and epsilon (pol delta and epsilon) are the major replicative polymerases and possess 3'-5' proofreading exonuclease activities that correct errors arising during DNA replication in the yeast Saccharomyces cerevisiae. This study measures the fidelity of the holoenzyme of wild-type pol epsilon, the 3'-5' exonuclease-deficient pol2-4, a(More)
DNA polymerases delta and epsilon (pol delta and epsilon) are the two major replicative polymerases in the budding yeast Saccharomyces cerevisiae. The fidelity of pol delta is influenced by its 3'-5' proofreading exonuclease activity, which corrects misinsertion errors, and by enzyme cofactors. PCNA is a pol delta cofactor, called the sliding clamp, which(More)
To investigate the nature of mutations induced by accelerated ions in eukaryotic cells, the effects of carbon-ion irradiation were compared with those of gamma-ray irradiation in the budding yeast Saccharomyces cerevisiae. The mutational effect and specificity of carbon-ion beams were studied in the URA3 gene of the yeast. Our experiments showed that the(More)
To clarify the functions of the Arabidopsis thaliana REV1 (AtREV1) protein, we expressed it in Escherichia coli and purified it to near homogeneity. The deoxynucleotidyl transferase activity of the recombinant AtREV1 was examined in vitro using a primer extension assay. The recombinant AtREV1 transferred one or two nucleotides to the primer end. It(More)
We studied the swimming orientation of the ciliated protozoan Paramecium aurelia in a static magnetic field (0.78 T). P. aurelia is a complex of species termed syngens, whose cell morphology appears similar on microscopic examination. In the magnetic field, the cells of some syngens gradually changed their swimming orientation so that they were swimming(More)
Radiophotoluminescence (RPL) photography has been proposed for the measurement of the spatial dose distribution of high radiation fields. A pulsed UV-LED illuminator was prepared as an excitation light source for the RPL photography. The fluorescence image of RPL material was observed by a gated intensified CCD camera. In a preliminary experiment, several(More)
The biological dosemeter that measures biological responses to ionising radiation is useful for radiation protection. This paper presents the development and characterisation of a gamma ray irradiation dosimetry system based on real-time PCR (polymerase chain reaction) methodology. Real-time PCR is used to amplify and simultaneously quantify a targeted DNA(More)
To identify individual cells exposed to a X-ray microbeam in a cell population, we developed a biocompatible microchamber-array chip using UV lithography of photopolymer SU-8. The center-to-center distance between microchambers is 50 mum including a wall of 15 mum height. Using the microchamber-array chip, we performed tracking of individual exposed cells.(More)
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