A Survey of the Structures of Mycolic Acids in Corynebacterium and Related Taxa

Abstract

Acid methanolysates of 104 strains of coryneform and related bacteria were examined for mycolic acids by TLC and mass spectrometry. The mycolic acids of Corynebacterium s.s. strains were not uniform in size and structure, and considerable variation existed within the approximate limiting range of C22 to C36. Two species, C. bovis and C. mycetoides, were particularly distinctive; the former had exceptionally low MW mycolic acids (C22-C32), whereas the latter contained major amounts of mycolates with side-chain possessing an odd number of C atoms. Caseobacter polymorphus contained mycolic acids of a similar size (C30-C36) to those of true corynebacteria. The mycolates of organisms assigned to the genus Rhodococcus were generally large (C30-C56), although a clear distinction between true corynebacteria and rhodococci cannot presently be made by analysis of mycolic acids alone. Strains labeled Arthrobacter roseoparaffinus, C. equi and C. hoagii contained mycolic esters with MW intermediate in size between those of true corynebacteria and rhodococci. The mycolic acid data correlate well with other major trends in coryneform taxonomy and support earlier suggestions that they are of value in the classification of the group.