52 



MICROBIAL CELL WALLS 



antigens.^*' ^^ Thus, some of the dideoxyhexoses charac- 

 terized by Westphal and his collaborators "*• " ^ and hep- 

 toses ' ^' ' " are present in the bacterial walls. The charac- 

 teristic spectra of the products of the Dische '^ reaction of 

 heptoses have been used to show that these monosaccharides 

 are located in the lysozyme-insoluble fraction of the wall, 

 clearly indicating that they are not part of the mucopeptide 

 structure."^ A typical result for the walls of Spirillum ser- 

 pens is shown in Fig. II. 



Much remains to be done in the investigation of the walls 

 of Gram-negative bacteria, and at the moment we have no 

 precise information about the number of different molecu- 

 lar or macromolecular subunits in the walls of this group. 

 At least we are now certain that mucopeptides are common 



Spirillum serpens walls 

 Untreated 



A — A Lysozyme-soluble 

 fraction 



400 



450 500 



Wavelength (m^) 



550 



600 



Fig. n. 



serpens. 



Spectra of Dische reaction products of walls of Spirillum 



