PRINCIPAL INVESTIGATOR (S ): Donald R. Ekberg, Elaine C. Silver, Judith L. 



Bushnay, and Edward W. Daniels 



EXPERIMENT TITLE/NUMBER : Nuclear and Cellular Division in Pelomvxa 



carolinensis During Weightlessness, P-1035 



PROGRAM/ MISSION : Biosatellite II 



CLASSIFICATION : Animal - Amoeba ( Pelomvxa carolinensis ) 



DISCIPLINE(S) : Cell biology 



OBJECTIVES : To study the effects of weightlessness on nuclear and cellular 

 division in a single cell, using the giant multinucleate amoeba Pelomvxa 

 carolinensis . 



PROTOCOL : The amoebae were cultured and subcultured, placed in a buffer and 

 fed Paramecium. Five complete units of 24 chambers were assembled 2 days 

 before launch. The organisms were loaded at F-18.5 hrs. The amoebae were 

 screened and counted as they were selected for the chambers. After the 

 amoebae and Paramecium were loaded, the chambers were filled with THAM glycyl 

 glycine buffer, with a small airspace left. The fixations were actuated 5 

 times inflight. At recovery, the organisms were counted, examined for mitotic 

 forms, food vacuoles counted, and the gross morphology described. 



EQUIPMENT : Experiment package with 24 chambers, each divided into three 5 ml 

 compartments containing either amoebae, Paramecium or fixitive. The chambers 

 were mounted on magnesium plates. Four of the chambers contained thermistors. 



RESULTS : There were no significant differences in division rates between 

 flight and control groups. There was a trend toward a higher division rate in 

 well fed Pelomvxa during weightlessness. Nuclear division during 

 weightlessness was synchronous, as in the controls. No difference was 

 apparent in the postflight cell division rates of the flight group when 

 compared to the controls. 



CONCLUSIONS : Flight vibration and acceleration had no observable effect upon 

 nuclear or cellular division of amoebae. 



PUBLICATIONS : 182, 183 



103 



