SUMMARY: Hydrolysates of cell-wall preparations of more than 60 strains of corynebacteria, lactobacilli, streptococci, staphylococci and other Gram-positive cocci have been examined by paper chromatography. A very high proportion of the amino acid moiety of the cell-wall complex could in each case be accounted for in terms of 3 or 4 of the amino acids alanine, glutamic acid, lysine, diaminopimelic acid, aspartic acid and glycine. These were associated with varying combinations of sugars and amino sugars. In general, each bacterial genus appears to have a characteristic pattern of cell-wall components, particularly in regard to the amino acids present. Variations in the relative proportions of the sugars appear to differentiate the individual species within a genus. The possible value of cell-wall composition as a taxonomic character is discussed.

The cell-wall compositions of 51 strains of Actinomyces, Nocardia, Streptomyces, Micromonospora, Mycobacterium and Propionibacterium have been investigated, together with those of 7 strains of Eumycetes. The cell walls of the actinomycetes were made up of sugars, amino sugars and amino acids (the latter few in number). The general pattern of components was thus identical with that previously found for Gram-positive bacteria. In the fungi, however, the mycelial walls were composed entirely of carbohydrate. These results suggest that the actinomycetes are not related to the fungi but should be classified with the bacteria proper. On the basis of cell-wall composition a classification of the actinomycetes is proposed, to consist of 3 families : Mycobacteriaceae containing the genera Mycobacterium, Nocardia and Corynebacterium; Streptomycetaceae containing Streptomyces and Micrmnospora ; and Actinomycetaceae with a single genus Actinomyces. The propionibacteria are probably related to Streptomyces. It is also suggested that a separate order Actinomycetales is unnecessary and that the families proposed can more suitably be included in the Eubacteriales.

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