70 MICROBIAL CELL WALLS 



TABLE 22 



Effects of Penicillin on Incorporation of Isotopes into Cell Wall or 



into Cell Protein and Nucleic Acid in Staphylococcus aureus and 



in Escherichia coli 



Data are expressed as specific activities (cpm/mg). 

 Reference 45. 



coli is not marked, and indeed Trucco and Pardee ^^ in 

 earlier experiments had concluded that penicillin did not 

 interfere with the synthesis of the wall of this organism. 

 As Escherichia coli wall possesses major protein, lipid, and 

 polysaccharide components, it seems likely that inhibition 

 of incorporation of the compounds into the mucopeptide 

 fraction of the wall of this Gram-negative organism may 

 have been more spectacular. Inhibition of mucopeptide 

 synthesis by penicillin has been clearly established by at 

 least three groups of investigators for Staphylococcus aureus. 

 The results of interference with wall synthesis in Escherichia 

 coli are conflicting, and Meadow ^^ has recently found that 

 a DAP-requiring mutant of Escherichia coli is unchanged 

 in its ability to incorporate [^^C] glucose [^^C] lysine and 

 [i*C] diaminopimelic acid into wall during the first 30 



