COMPARATIVE INVESTIGATIONS OF THE RADIATION SENSITIVITY OF BACTERIUM COLI AND YEAST ESPECIALLY IN APPLICATION OF ENERGETIC BEAMS

Journal Article · Thu Dec 01 04:00:00 EST 1960 · Z. Naturforsch

OSTI ID:4070613

Sommermeyer, K; Magnus, H

For testing the hypotheses oniginated by Dobson (deuteron research with B. coli), by Houtermans (temperature research with B. coli), and by Alper (analyses of the RBW factor in yeast) that B. coli in the presence of energetic radiation is killed for tbe most part by radioinduced inactivating substances (IS) with large diffusion lengths and that yeasts are killed by a direct hit in the vital substances, a comparative investigation of the radiation sensitivity of B. coli and haploid yeast oells was made. The assumptions of Dobson, Houtermans, and Alper could therefore be confirmed. On going below the freezing point and by exposure to alpha radiation, B. coli shows, in agreement with Houtermans' findings, a jump-like increase of D/sub 1/>i. Yeast shows, under the same conditions, only a gradual increase. B. coli can be almost completely killed by diffusable IS which are formed by uv in very high doses in agar, whereas yeast cells with the same radiation sensitivity exhibit no effect. After irradiation of the agar both with uv and with energetic radiation, at high dose rates, diffusable IS with short life (T,. up to about 15 sec) can be detected. The reaction mechanism for tbe origin of this IS (multi-collision reactions) and for its destruction in agar is shown to be extremely complicated. The diffusion length of the IS in agar was determined to be about 80 mu and its diffusion coefficient about 0 6 x 10/sup -5/ cm/sup 2//sec. This corresponds to a mean molecular weight of about 200. The ion yield in the IS formation is strongly dependent on the O/sub 2/ concentration for x radiation and is independent for alpha radiation. If the agar is in the open atmosphere, the ion yield for alpha radiation is 10 times greater than for x radiation. The number of IS molecules diffusing to coli cells, which are necessary for destruction, is divided by the ion yield in its origin for x radiation by a factor of lO/sup 9/. (tr-auth)

• Research Organization: Universitat, Freiburg i. B.; and Rontgeninstitut der Stadt. Krankenanstalten, Karlsruhe, Ger.
• NSA Number: NSA-15-012766
• OSTI ID: 4070613
• Journal Information: Z. Naturforsch, Journal Name: Z. Naturforsch Vol. Vol: 15b
• Country of Publication: Country unknown/Code not available
• Language: German

Related Subjects

ALPHA PARTICLES
BACTERIA
BEAMS
BIOLOGY AND MEDICINE
ENERGY
IONS
LIFETIME
OXYGEN
RADIOSENSITIVITY
X RADIATION
YEASTS