18 MICROBIAL CELL WALLS 



Other groups of microorganisms. Although there have been 

 many studies of what has been assumed to be wall material 

 after extraction of whole microorganisms with alkali, these 

 studies have not been included in the present survey. The 

 only comparative study of the old methods of isolating walls 

 by alkaline digestion and the new methods by mechanical 

 disintegration is that of Aronson and Machlis ^^ for the 

 walls of the fungus Allomyces macrogynus. Their results 

 are presented in Table 3 and show a loss of wall constituents 

 when isolation is performed by extraction with alkali. 



Several typical analyses of the isolated walls of a yeast, 

 a green alga, and a Gram-positive and a Gram-negative 

 bacterium are summarized in Table 4. One conspicuous 

 feature illustrated in Table 4 is the high amino sugar con- 

 tent of the wall of the Gram-positive organism in compari- 

 son to the other microorganisms. The major classes of sub- 



TABLE 3 



The Composition of Walls of Allomyces macrogynus isolated by 

 Alkaline Digestion and by Sonic Oscillation 



