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UVA1 induces the formation of 8-hydroxy-2'-deoxyguanosines (8-OH-dGs) and cyclobutane pyrimidine dimers (CPDs) in the cellular genome. However, the relative contribution of each type of damage to the in vivo genotoxicity of UVA1 has not been clarified. We irradiated living mouse skin with 364-nm UVA1 laser light and analyzed the DNA damage formation and(More)
  • K Hieda
  • 1994
The recent development of irradiation systems using synchrotron radiation (SR) as a source is enabling researchers to obtain intense monochromatic photons having a narrow bandwidth in the vacuum-UV (VUV) and soft X-ray regions. We can thus systematically study the photon energy dependence of DNA damage formation in these energy regions. The photon energy(More)
Using a synchrotron irradiation system pBR322 plasmid DNA was irradiated under vacuum by monochromatic X-rays having five specific photon energies (2.147, 2.153, 2.159, 2.168 and 2.199 keV) both on and off the K-absorption peak (2.153 keV) of phosphorus. The single- and double-strand breaks (ssb and dsb) were measured as conversions of the closed circular(More)
The effects of K-shell absorption of phosphorus atoms on yeast cells were investigated using synchrotron X-rays that were tuned to the resonance absorption peak (2153 eV). Three types of cellular effect (cell inactivation, induction of gene conversion at the trp-5 locus, and cell membrane impairment (changes in the permeability] were measured. It was(More)
We investigated the wavelength dependence of cyclobutane thymine dimer and (6-4)photoproduct induction by monochromatic UV in the region extending from 150 to 365 nm, using an enzyme-linked immunosorbent assay with two monoclonal antibodies. Calf thymus DNA solution was irradiated with 254-365 nm monochromatic UV from a spectrograph, or with 220-300 nm(More)
Using an electron storage ring as a source of radiation, the wavelength dependence of inactivation and membrane damage in yeast cells (Saccharomyces cerevisiae) was investigated in the range from 145 to 254 nm, with special reference to the effects of vacuum-uv radiation. The cells were irradiated on a Millipore filter in a moist chamber filled with water(More)
PURPOSE To determine directly the minimal distance between two ssbs on complementary strands in circular DNA that are not observed as a dsb by electrophoresis. MATERIALS AND METHODS 3.2 kbp DNAs with cohesive overhangs of various lengths were systematically generated by a newly devised method and electrophoresed in agarose slabs. RESULTS At 4 degrees C,(More)
A small and robust dosimeter for determining the biologically effective dose of ambient UV radiation has been developed using UV-sensitive mutant spores of Bacillus subtilis strain TKJ6312. A membrane filter with four spots of the spores was snapped to a slide mount. The slide was wrapped and covered with two or more layers of polyethylene sheet to protect(More)