EXPERIMENTALLY INDUCED CHROMOSOME ABERRATIONS IN PLANTS : II. THE EFFECT OF CYANIDE AND OTHER HEAVY METAL COMPLEXING AGENTS ON THE PRODUCTION OF CHROMOSOME ABERRATIONS BY X-RAYS |
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| Authors: | B. A. Kihlman T. Merz C. P. Swanson |
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| Affiliation: | From the Department of Biology, The Johns Hopkins University, Baltimore |
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| Abstract: | ![]()
The discovery of Lilly and Thoday, that the presence of potassium cyanide (KCN) increases the production of chromosome aberrations by x-rays in anoxia, but has no effect on the production of chromosome aberrations by x-rays in air, was confirmed. In the presence of cyanide, the effect of a given dose of x-rays in nitrogen was found to be even greater than the effect of the same dose of x-rays in air. The cyanide effect on x-ray breakage in nitrogen was obtained at cyanide concentrations as low as 2 x 10–5 M. The breakage obtained after the combined x-ray-cyanide treatments was of the x-ray type, as evidenced by the distribution of breaks within and between the chromosomes. A number of other heavy metal complexing agents as well as some other compounds were tested for their ability to increase x-ray breakage in nitrogen and air. Of these compounds only cupferron proved to be effective. The results are discussed and it is concluded that the increased x-ray breakage in the presence of cyanide or cupferron cannot be due to an accumulation of peroxides. Instead it is suggested that the cyanide effect may be due to a complex formation between the active agents and heavy metals, presumably iron, within the chromosomes. The consequences of this hypothesis on the concept of the "oxygen effect," are discussed. |
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