Search

Fertilization and subsequent embryogenesis of newts occurred normally under microgravity in two Astronewt flight experiments. By accumulation of the results from the amphibian flight experiments including ‘Astronewt’, it is considered that gravity has rather small effects on the early development of amphibian eggs. However, some temporary abnormalities, which recover in the course of the further developmental process, have been observed. Some regulations may occur in whole embryos. For a thorough knowledge about the role of gravity in morphogenesis, we need to investigate the gravitational effects on a single cell in a whole embryo. We propose a new experimental system with sea urchin embryos and micromeres for further studies at a cellular level of the effects of gravity on morphogenesis.

Publisher Summary This chapter discusses the frog experiment onboard space station Mir. Frogs sitting on a surface bent their neck backward sharply, did not fold their hind limbs completely, and pressed their abdomen against the substrate. They walked backwards in this posture. This typical posture resembles that adopted during the emetic behavior process on the ground, although the posture in space lasts much longer. The possible mechanism of induction of this unique posture in orbit is discussed in the chapter. Frogs in this posture are considered to be in an emetic state, possibly due to motion sickness. Response behavior to some external stimuli was observed in orbit. Body color change in response to the background color appeared to be delayed or slowed down. Response behavior to other stimuli showed little change as long as the animal maintained contact with a substrate. Once it left the surface, the floating frog could not control its movements to provide coordinated motility for locomotion and orientation.