5 ML 



5 ML 



CENTRIFUGE 



24-HOUR 17 ML 



AGAR SLANTS NACL 



CELLS 

 IN NACL 



1 ML 



I ML 



COMPLETE 

 BROTH 



ISOLATIONS 



If 



3 ML 



10* 100 UNITS 



DILUTION PENICILLIN 

 IN MIN. MED. 



COMPLETE 

 AGAR 



MINIMAL 

 BROTH 



IN 3 ML 

 OF NACL 



COMPLETE 

 BROTH 



Fig. 17.1 — -Diagram showing methods for the production of radiation-induced auxotrophic 

 mutations in Salmonella and for their isolation by screening through minimal medium 



containing penicillin. 



PAPER DISC METHOD FOR TESTING BIOCHEMICAL MUTANTS 



TEST STRAIN 



NEEDLE TRANSFER 



24-HR BROTH DISTILLED Hg 



PAPER DISKS 



SALTS +GLUCOSE + 

 AGAR + NUTRILITE 



Fig. 17.2 — Diagram showing method for determining the particular nutrilite required by 

 the auxotrophs isolated as in Figure 17.1. .\ series of Petri plates is used, each containing 



a different test substance. 



