Section 15
Chapter 14,025

Effect of mitomycin-C on the frequency of chromosome aberrations produced by X-rays

Matsuura, H.; Tanifuji, S.; Saho, T.; Iwabuchi, M.

American Nat 97(894): 191-193


DOI: 10.2307/2458907
Accession: 014024041

The modifying effect of mitomycin-C on the frequency of X-ray-induced chromosome aberrations was investigated with the ovular tissue cells of Trillium kamtschaticum. Simple mitomycin-C treatment was found to be ineffective in causing any chromosome breakage when using the same concentration of the chemical and the same period of treatment as employed in the combination treatment. From observations on metaphase cells fixed 48 hours after irradiation, it was ascertained that the frequencies of breaks rejoined to form exchanges, both of chromatid and isochromatid types, are higher in the combination treatment than in simple irradiation. The total frequency of all visible breaks is also increased when radiation and mitomycin-C treatment are combined. These results indicate that the rapid rejoining of X-ray-induced breaks is prevented by mitomycin-C and the duration of an open period during which broken ends retain their potential rejoinability is also prolonged. Since mitomycin-C is known to specifically inhibit DNA synthesis in bacteria and viruses, its modifying effect on the rejoining of X-ray-induced breaks seems to indicate the involvement of DNA synthesis in this process.

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