ABSTRACT
Biological effects of gravity was examined in embryonic development of Japanese red bellied newt. Two space newt missions were conducted in 1994 and 1995. The Second International Microgravity Laboratory was flown in 1994 as one of the SpaceLab missions. Space Flyer Unit, a Japanese space platform, was delivered to the earth orbit by the third launch of the H-II rocket and retrieved by Space Shuttle in 1996. Female newts were induced to lay eggs in orbit at these two space missions. Eggs were successfully obtained on both missions, and exposed to space environment from its early developmental stages. Morphology of the embryos was found not deviated from those developed on ground, as long as in the images taken in orbit or the examined specimen retrieved to ground. On the other hand, pathological changes were discovered in several organs of the adult newts that returned alive from their space flight.
Subject(s)
Adaptation, Physiological , Salamandridae/embryology , Salamandridae/physiology , Space Flight , Weightlessness , Animals , Embryo, Nonmammalian/physiology , Embryonic Development , Female , Liver/cytology , Liver/pathology , Lung/pathology , Lung/ultrastructure , Microscopy, Electron , Photography , Stomach Ulcer/etiology , Stress, PhysiologicalABSTRACT
AstroNewt experiment explores the effects of earth gravity on the early development of Japanese red-bellied newt, Cynops pyrrhogaster. Since female newts keep spermatophore in cloaca, fertilized eggs could be obtained without mating. Fertilization of newt's egg occurs just prior to spawning, so that gonadotrophic cues applied to females in orbit leads to laying eggs fertilized just in space. A property of newt being kept in hibernation at low temperature may be of great help for the space experiment carried out with much limited resources. A general outline of the AstroNewt project is shown here in addition to some technical advances for the development of the project. Experimental schemes of two space experiments (IML-2 in summer 1994 and unmanned SFU at the beginning of 1995) are also shown.
Subject(s)
Salamandridae/embryology , Space Flight , Weightlessness , Animals , Chorionic Gonadotropin/pharmacology , Female , Fertilization/physiology , Hibernation , Japan , Male , Oxygen Consumption/physiology , Research Design , Salamandridae/physiology , Sexual Behavior, Animal/drug effects , Sexual Behavior, Animal/physiology , Spacecraft , TemperatureABSTRACT
Sustained release formulation of hCG, hCG minipellet, was applied to induce oviposition of newt. Period of egg spawning was prolonged with a certain delay of its initiation. When hCG minipellet was injected to newt that was hibernating, it induced egg spawning even after one month of hibernation. Results suggest that minipellet keeps steady concentration of hCG at the effective level for longer period. For the study on early development of newt egg, it is essential to obtain egg on orbit. hCG minipellet makes it possible even at launch slip or early "late access".
