INFLUENCE OF SIMULATED MICROGRAVITY ON THE LONGEVITY OF INSECT-CELL CULTURE

Simulated microgravity within the NASA High Aspect Rotating-Wall Vesse l (HARV) provides a quiescent environment to culture fragile insect ce lls. In this vessel, the duration of stationary and death phase for cu ltures of Spodoptera frugiperda cells was greatly extended over that a chieved in shaker-flask controls. For both HARV and control cultures, S. frugiperda cells gave to concentrations in excess of 1 x 10(7) viab le cells ml(-1) with viabilities greater than 90%. In the HARV, statio nary phase was maintained 9-15 days in contrast to 4-5 days in the sha ker flask. Furthermore, the rate of cell death was reduced in the HARV by a factor of 20-90 relative to the control culture and was characte rized with a death rate constant of 0.01-0.02 day(-1). Beginning in th e stationary phase and continuing in the death phase, there was a sign ificant decrease in population size in the HARV versus an increase in the shaker flask. This phenomenon could represent cell adaptation to s imulated microgravity and/or a change in the ratio of apoptotic to nec rotic cells. Differences observed in this research between the HARV an d its control were attributed to a reduction in hydrodynamic forces in the microgravity vessel. (C) 1997 Elsevier Science, Inc.