35 



trypsinization, resuspended at a density of 0.5 to 1.0 x 



5 

 10 cells/ml in the appropriate media and added in 1 . Oral 



aliquots to scintillation vials. After 12-16 hours of 



growth lOOul of each inhibitor concentration (in culture 



media) being tested were added to triplicate cultures to 



achieve the desired final concentration of inhibitor. 



Growth was allowed to proceed for 48 hours after which time 



the cells were harvested for counting. Cultures were gently 



rinsed two times with 2.0ml cold balanced salt solution 



2+ 2 + 

 (Gey's A without Ca or Mg ) and treated with 1.0ml tryp- 



sin-EDTA for 5 minutes. After detachment from the glass, 



9.0ml of Gey ' s A solution was added to each vial and cells 



were counted directly. 



EL4 cells were grown in suspension in scintillation 

 vials for 12-16 hours, exposed to inhibitor for 48 hours 

 and counted directly by dilution with Gey ' s A. 



Inhibition of CHO H-7 and H-7Wcr cell growth by ADGG 

 or a-amanitin was also examined by cell number determination 

 but the cells were grown in plastic multiwell tissue culture 



plates (Corning) . CHO cells H-7 and H-7Wcr were plated at 



4 2 



1 x 10 cells/cm in 1.0ml 10-12 hours prior to the addi- 

 tion of inhibitor. Forty-eight hours after addition of 

 50ul of inhibitor, the cells were rinsed two times with 

 cold PBS and removed from the vessel surface by two 

 minutes of treatment with 1.0ml trypsin-EDTA. Aliquots 

 were removed directly into 10ml PBS in a siliconized 

 scintillation vial and immediately counted with the cello- 

 scope. Care was taken to ensure that cell clumps were well 



