title: The role of gravity in chick embryogenesis.
abstract: Thirty fertilized chick eggs preincubated for 0, 7 and 10 days on earth (10 eggs each) were flown in the space shuttle 'Endeavour' and further incubated for 7 days under microgravity. Twenty out of thirty eggs (9/10 ten-day-old; 10/10 seven-day-old; 1/10 zero-day-old) were recovered alive after landing. The only living embryo of the zero-day-old group died 24 days after launch, and was comparable to a 16-day-old embryo. The high mortality of the 0-day-old eggs appeared to be related to the specific inner structure of the egg. Simulation experiments performed on earth indicated that when yolk stayed in the albumen for more than 2 days, most of the embryos died. The subtle difference in specific gravity between the yolk (1.029) and albumen (1.040) plays a critical role in early chick embryogenesis.
authors.affiliation: Department of Biochemistry, School of Dentistry, Showa University, Tokyo, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Suda
authors.forename: E
authors.initials: E
authors.lastname: Abe
authors.forename: T
authors.initials: T
authors.lastname: Shinki
authors.forename: T
authors.initials: T
authors.lastname: Katagiri
authors.forename: A
authors.initials: A
authors.lastname: Yamaguchi
authors.forename: S
authors.initials: S
authors.lastname: Yokose
authors.forename: S
authors.initials: S
authors.lastname: Yoshiki
authors.forename: H
authors.initials: H
authors.lastname: Horikawa
authors.forename: G W
authors.initials: GW
authors.lastname: Cohen
authors.forename: S
authors.initials: S
authors.lastname: Yasugi
mesh_terms: D000818:Animals; D002642:Chick Embryo / Q000254:growth & development*; D006112:Gravitation; D016019:Survival Analysis