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NASA NTRS1999

Modulation of Radiogenic Damage by Microgravity: Results From STS-76

The STS-76 (Shuttle-Mir 3) spaceflight provided an opportunity to test two questions about radiation responses in C. elegans. First, does the absence of gravity modify the dose-response relation for mutation and chromosome aberration and second, what are the features of the mutation spectrum resulting from exposure to cosmic rays? These questions were put to the test in space using the ESA "Biorack" facility which was housed in the Spacehab module aboard shuttle Atlantis. The mission flew in March, 1996 and was a shuttle rendezvous with the Russian space station Mir.

Nelson, Gregory↗

NASA NTRS1993

(abstract) Effects of Radiation and Oxidative Stress on Development and Morphology of Intestinal Cells

Intestinal cells when subjected to oxidative stress or radiation exhibit abnormal nuclear divisions observed as: 1) supernumerary cell divisions in anterior intestinal cells or 2) incomplete nuclear division and the persistence of anaphase bridges between daughter nuclei. Two oxygen sensitive mutants, mev-1 and rad-8 were observed to exhibit spontaneous supernumerary nuclear divisions at low frequency. N2 can be induced to undergo these divisions by treatment with the superoxide dismutase (SOD) inhibitor diethyl dithicarbamate or with the free radical generator methyl viologen. By contrast, the free radical generator bleomycin produces anaphase bridges in N2 intestinal nuclei at high frequency. Intestinal anaphase bridges can be induced by ionizing radiation and their formation is dependent on dose and radiation type.

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