823 Journal of General Microbiology (1982), 128,823-828. Printed in Great Britain Studies on the Mycolic Acids from the Walls of Mycobacterium microti

Mycobacterium microti walls contained three types of mycolic acids, very similar to those found in Mycobacterium tuberculosis. An a-mycolate with two cyclopropane rings, a methoxymycolate with one cyclopropane ring and a methoxyl group, and a ketomycolate with one cyclopropane ring and a keto group were partially characterized. The mycolates made up 34 % (by weight) of the peptidoglycan-arabinogalactan-mycolate wall skeleton. Young exponential phase cultures and organisms harvested from mouse lungs contained high proportions of ketomycolates; older cultures had roughly equal proportions of keto- and methoxymycolates. The proportion of a-mycolates increased slightly with age of culture, but was always less than one-third of the total