ADAPTATION TO PANTOTHENATE DEFICIENCY 



22-32 



ate (2007, 207, 107, 27 and 07 per liter) and inoculated with a 

 mixed inoculum of cultures 2154 and adapted 2154. The inoculum 

 consisted of about 125 adapted cells and around oOO unadapted. Fig- 

 ure 22-8 shows the growth obtained as measured in colorimeter 

 readings. The cultures were observed for another two weeks beyond 

 the time shown on the graph, during which no appreciable change in 

 the amount of growth occurred. 



400- 



300- 



CQ 



3 



200- 



100- 



20 40 60 80 100 120 140 160 

 HOURS 



Fig. 22-8 Growth of Mixed Cultures of 2154 and Adapted 

 2154 in Various Concentrations of Pantothenic Acid. 



Rate and total amount of growth of the mixed cultures decreases 

 as the concentration of pantothenate decreases from 2007 to 107, 

 but as it is dropped to 27 and 07, there is a lag of 4 days after which 

 rapid growth ensues. The total amount of growth is greater at 27 

 and 07 than at the intermediate amounts of 207 and 107. The shape 

 of the curves in 2007, 207, and 107, are characteristic of growth 

 curves for pantothenate -dependent culture 2154, and those at 27 and 

 07 comparable to those of adapted 2154. When both types of cells 

 are present, the non-synthesizing cells determine the growth in high 



