Peptidoglycan Bacillus cereus

The resistance of Bacillus cereus cell-wall peptidoglycan to lysozyme action200 is due to the majority of the 2-amino-2-deoxy-D-glucosyl residues having free (nonsubstituted) amino groups. Polysaccharide and peptide components of the cell walls were converted into material susceptible to lysozyme by N-acetylation with acetic anhydride. 

Variations also occur in the muramic acid itself. In S. aureus approximately half of the muramic acid residues bear an acetyl group on the 6 position. This modification renders the peptidoglycan insensitive to degradation by lysozyme. Similar modifications have been reported in some strains of Proteus, Neisseria and Pseudomonas. Loss of some of the iV-acetyl residues from the V-acetylglucosamine of some Bacillus cereus strains also has the effect of rendering the peptidoglycan resistant to lysozyme. 

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