154 



NITROGEN METABOLISM 



Q ■ • NORMAL CULTURE 



•-C-- CULTURE PLUS 



\fj^. PENICILLIN/ML. 



8 20 22 



T 1 I I n T 



6 8 10 12 14 16 

 TIME (in hours) 



FIG. I0.2. — Effect of penicillin on nucleic acid metabolism of Staph, 

 aureus. %NA=percentage by weight of total nucleotide, 

 %Nt= percentage by weight of nucleotide extractable with 

 5% trichloracetic acid, NA-Nt=total nucleic acid, DW— dry 

 weight of organism in /xg./ml. [17] 



