DEVELOPMENT OF THE BRINE SHRIMP ARTEMIA IS ACCELERATED DURING SPACEFLIGHT

Developmentally arrested brine shrimp cysts have been reactivated duri ng orbital spaceflight on two different Space Shuttle missions (STS-50 and STS-54), and their subsequent development has been compared with that of simultaneously reactivated ground controls. Flight and control brine shrimp do not significantly differ with respect to hatching rat es or larval morphology at the scanning and transmission EM levels. A small percentage of the flight larvae had defective nauplier eye devel opment, but the observation was not statistically significant. However , in three different experiments on two different flights, involving a total of 232 larvae that developed in space, a highly significant dif ference in degree of flight to control development was found. By as ea rly as 2.25 days after reactivation of development, spaceflight brine shrimp were accelerated, by a full instar, over ground control brine s hrimp. Although developing more rapidly, flight shrimp grew as long as control shrimp at each developmental instar or stage. (C) 1994 Wiley- Liss, Inc.