Introduction to The Proposed Space Experiments Aboard The ISS Using The Silkworm, Bombyx mori

The authors have a plan to examine the biological effects of cosmic rays by loading the eggs of the silkworm, Bombyx mori, in the International Space Station (ISS) for 3 months. In advance of the project, several ground experiments have been performed. In order to investigate the biological effects of radiation, heavy ion particles were used instead of cosmic rays. Heterozygous eggs of the black-striped strain (pS/p) were irradiated with Carbon (C), Neon (Ne) or Ferrous (Fe) ion particles. At the fifth instar stage, larvae that hatched from these eggs showed white spots on their backs against the black or dark brown of their integument. These are somatic mutations which seem to be caused by the effects of radiation on the pS gene. The incidence of this somatic mutation increased in proportion to dose and linear energy transfer of C and Ne ion particles, and it was higher after resumption of embryogenesis in eggs that had been irradiated after diapause termination as compared with eggs irradiated while still in diapause. Irradiation by more than 0.04 Gy of Fe ion particles to diapause-terminated eggs induced a significant incidence of somatic mutation compared with controls (P