FREE MYCOLIC ACIDS AS CRITERIA IN CLASSIFICATION OF GORDONA AND RHODOCHROUS COMPLEX

The methyl esters of free mycolic acids from representative strains of G. bronchialis, G. rubra, G. terrae and Nocardia kirovani each gave, on mass spectroscopy, homologous series of anhydromycolic esters containing from 1-4 double bonds with the main components of the parent mycolic acids centered on 56, 58, 62 or 64 C atoms (total range from C22-C66). The mycolic acids from the Gordona strains, with chain lengths centered around C60, form a group intermediate in size between nocardiomycolic acids (centered around C50) and mycolic acids sensu stricto (centered around C70-C90); these are different from those of the rhodochrous complex which have anhydromycolates ranging from C34-C50. Gordonae are more closely related in their mycolic acid composition to Nocardia than to Mycobacterium but can be distinguished from each of these genera.