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fertilization of sea urchin eggs and sperm motility are negatively impacted under low hypergravitational forces significant to space flightSperm and other flagellates swim faster in microgravity (microG) than in 1 G, raising the question of whether fertilization is altered under conditions of space travel. Such alterations have implications for reproduction of plant and animal food and for long-term space habitation by man. We previously demonstrated that microG accelerates protein phosphorylation during initiation of sperm motility but delays the sperm response to the egg chemotactic factor, speract. Thus sperm are sensitive to changes in gravitational force. New experiments using the NiZeMi centrifugal microscope examined whether low hypergravity (hyperG) causes effects opposite to microG on sperm motility, signal transduction, and fertilization. Sperm % motility and straight-line velocity were significantly inhibited by as little as 1.3 G. The phosphorylation states of FP130, an axonemal phosphoprotein, and FP160, a cAMP-dependent salt-extractable flagellar protein, both coupled to motility activation, showed a more rapid decline in hyperG. Most critically, hyperG caused an approximately 50% reduction in both the rate of sperm-egg binding and fertilization. The similar extent of inhibition of both fertilization parameters in hyperG suggests that the primary effect is on sperm rather than eggs. These results not only support our earlier microG data demonstrating that sperm are sensitive to small changes in gravitational forces but more importantly now show that this sensitivity affects the ability of sperm to fertilize eggs. Thus, more detailed studies on the impact of space flight on development should include studies of sperm function and fertilization.
Document ID
20040088759
Document Type
Reprint (Version printed in journal)
Authors
Tash, J. S.
(University of Kansas Medical Center Kansas City, Kansas 66160, United States)
Kim, S.
Schuber, M.
Seibt, D.
Kinsey, W. H.
Date Acquired
August 21, 2013
Publication Date
October 1, 2001
Publication Information
Publication: Biology of reproduction
Volume: 65
Issue: 4
ISSN: 0006-3363
Subject Category
Life Sciences (General)
Funding Number(s)
CONTRACT_GRANT: U54 HD-33994
Distribution Limits
Public
Copyright
Other
Keywords
NASA Discipline Developmental Biology
Non-NASA Center