Meeting Abstract

P1.43  Jan. 4  The effects of simulated microgravity on skeletal morphology and growth in Xenopus laevis. HAUPTMEIER, C.L.*; OLSON, W.M.; WIENS, D.J.; University of Northern Iowa; University of Northern Iowa; University of Northern Iowa

During amphibian development, neural crest cells (NCC) migrate away from the neural tube and into the head, where they give rise to many cartilages of the head and visceral skeleton. The path and destination of these cells are influenced by cellular environment, but the specific role of gravity during migration is not completely understood. We tested the effects of altered gravity on the developmental morphology of head cartilages in Xenopus laevis embryos. We simulated microgravity using two Slow-Turning Lateral Vessels (STLV). Embryos were dejellied, loaded into the STLVs at Nieuwkoop and Faber (1967) stage 11 (mid-gastrulation), and raised until stage 45 (onset of feeding). Tadpoles were then cleared and stained for cartilage. There were no consistent, statistically significant differences in mortality, total length, or snout-vent length among groups. Comparing overall morphology, structural abnormalities were more common in tadpoles developed under simulated microgravity. Abnormalities were largely restricted to NCC-derived cartilages; mesodermally derived elements (parachordals, median visceral elements) were rarely affected. Head cartilages tended to be larger in the vibration control. BrdU staining showed that increased size in the vibration control was not due to increased mitosis. We conclude that abnormal development is more frequent in simulated microgravity, and that vibration alone also influences development.