Genes and Environment
Online ISSN : 1880-7062
Print ISSN : 1880-7046
Search
OR
Browse
Search
Volume 32 , Issue 2
Showing 1-5 articles out of 5 articles from the selected issue
    • |<
    • <
    • 1
    • >
    • >|
COMMENTARY
REGULAR ARTICLE
  • Hideshi Koshida, Takefumi Onodera, Risa Arai, Yohei Inaba, Shigehisa U ...
    Type: Regular article
    Volume 32 (2010) Issue 2 Pages 25-30
    Released: June 03, 2010
    JOURNALS FREE ACCESS
    Sidestream smoke from smoldering cigarette is the major source of environmental cigarette smoke. Cigarette smoke condensate (CSC) from sidestream smoke has been known to be mutagenic in Ames' Salmonella strains in the presence of an S9 metabolic activation system. We investigated a novel photomutagenic property of CSC with UVA-irradiation in the absence of metabolic activation. CSCs were collected from sidestream smoke of three Japanese brands of cigarettes using a smoking machine according to the ISO Standard. Bacterial cells with or without CSC were irradiated using a UVA light (320-400 nm) for 10-30 min. Photomutagenicity of CSC was more evident in E. coli WP2uvrA/pKM101 than in S. typhimurium TA100 and TA98. Photomutagenic potency (number of induced revertants/μg CSC) of sidestream CSC from Mild Seven One, an ultra-light tar cigarette, showed equal mutagenic potency to that from Seven Stars, a high tar cigarette. Photomutagenic potency of Pianissimo One, an ultra-light tar cigarette, was significantly higher than that of Seven Stars or Mild Seven One. We could not detect any increase of 8-OHdG formation in DNA isolated from cells irradiated with UVA in the presence of CSC. CSC with UVA irradiation caused A:T→T:A transversions most frequently, followed by A:T→G:C transitions. CSC was not photomutagenic in WP2/pKM101, indicating that the DNA damages generated by UVA-irradiated CSC were efficiently repaired by a nucleotide excision repair system. In addition, an error-prone translesion DNA synthesis by DNA polymerase RI encoded by mucAB genes on pKM101 is considered to be involved in photomutagenesis of CSC. We speculate a possible mechanism of production of radicals followed by DNA bulky adduct formation.
    View full abstract
    Download PDF (419K)
  • Toshinori Suzuki, Tomoko Inoue, Michiyo Inukai
    Type: Regular article
    Volume 32 (2010) Issue 2 Pages 31-36
    Released: June 03, 2010
    JOURNALS FREE ACCESS
    When 8-oxo-7,8-dihydro-2'-deoxyguanosine in potassium phosphate buffer of pH 7.4 was irradiated by UV light from a mercury lamp, two major products were formed. They were identified as the diastereomers of spiroiminodihydantoin deoxyribonucleoside on the basis of their identical ESI-MS and UV spectra and HPLC retention times with those of the authentic samples. Degradation of 8-oxo-7,8-dihydro-2'-deoxyguanosine by UV light was faster than those of 2'-deoxyguanosine, 2'-deoxycytidine, 2'-deoxyadenosine, and thymidine. Sunlight also generated the diastereomers of spiroiminodihydantoin from 8-oxo-7,8-dihydro-2'-deoxyguanosine. The results suggest that sunlight may induce 8-oxo-7,8-dihydroguanine oxidation in DNA, generating spiroiminodihydantoin in humans.
    View full abstract
    Download PDF (365K)
LETTER TO THE EDITOR
    • |<
    • <
    • 1
    • >
    • >|
feedback
Top