The HPLC-double-cluster pattern of some Mycobacterium gordonae strains is due to their dicarboxy-mycolate content

Abstract

The mycolic acids of several strains of Mycobacterium gordonae were examined by chromatographic and spectroscopic techniques. Both HPLC and TLC revealed two patterns of mycolates among the M. gordonae strains studied. As determined by TLC, one pattern was composed of α-, methoxy-and keto-mycolates ; the other was composed of these mycolates plus an additional component, which was identified as dicarboxy-mycolates. The dicarboxymycolates were only found in those M. gordonae strains that displayed a so-called HPLC-double-cluster pattern. Detailed structural analyses of the dicarboxy-mycolates indicated that these compounds contained predominantly 61-65 carbon atoms (C 63 was the major component) and a trans-1,2-disubstituted cyclopropane ring. Thus, the dicarboxy-mycolate content of strains of M. gordonae determines their HPLC pattern. In spite of the differences in their HPLC patterns, and although they belonged to different PCR-restriction length polymorphism clusters, all of the M. gordonae strains examined in this study were closely related on the basis of the structural features of their α-, keto-and methoxy-mycolates ; the predominant α-mycolates contained two cis-1,2-disubstituted cyclopropane rings, the major keto-mycolates contained a trans-1,2-disubstituted cyclopropane ring and the methoxy-mycolates contained one cis-or one trans-1,2-disubstituted cyclopropane ring. It is noteworthy that the strains containing dicarboxymycolates also displayed significant amounts of α-mycolates that contained one cis-1,2-disubstituted cyclopropane ring and one cis double bond. The results obtained in this study demonstrate heterogeneity among M. gordonae strains.

Analysis of the structure of mycolic acids of Mycobacterium simiae reveals a particular composition of α-mycolates in strain ‘habana’ TMC 5135, considered as immunogenic in tuberculosis and leprosy

“…The a-mycolates appeared unexpectedly long in comparison with those found in pathogenic mycobacteria (Minnikin, 1982;Watanabe et al, 2001Watanabe et al, , 2002, but it is uncertain if additional disubstituted cyclopropane rings or double bonds are also present in the mero chains of a-and keto-mycolates, as found for different strains of the Mycobacterium tuberculosis complex, Mycobacterium kansasii and Mycobacterium avium (Watanabe et al, 2001(Watanabe et al, , 2002. The same general mycolic acid composition as that of M. simiae has also been found in M. avium (Watanabe et al, 2001(Watanabe et al, , 2002, although pathogenic mycobacteria mostly contain a1-mycolates with two cis disubstituted cyclopropane rings (Minnikin, 1982;Watanabe et al, 2001Watanabe et al, , 2002; however, this is also similar to the mycolic acid composition of the saprophytic species M. gordonae (Astola et al, 2002).…”

“…EI-MS provides information on the meroaldehyde chains, where cyclopropane rings and oxygenated functions are present (Minnikin, 1982), and on the methyl esters, which are diagnostic of the branched chains located at the a position (Minnikin, 1982). FAB-MS reveals [M+Na] + ions indicative of the molecular masses of the different molecular species of mycolates (Astola et al, 2002).…”

“…Electron-impact MS (EI-MS) and fast-atom bombardment MS (FAB-MS) were performed in a VG AutoSpec instrument, as previously reported (Astola et al, 2002). For FAB-MS, m-nitrobenzyl alcohol was used as matrix and the samples were doped with NaCl.…”

Deletion of kasB in Mycobacterium tuberculosis causes loss of acid-fastness and subclinical latent tuberculosis in immunocompetent mice

“…12). The protons of the allylic methyl branch of the proximal trans-double bond resonated as a doublet at 0.94 ppm (J 6.6 Hz) and the terminal methyl at 0.84 ppm (26,27). In contrast, spectra of total MAs from the WT strain revealed the absence of allylic methyl branch protons (0.94 ppm) and of trans-double bond (5.24 ppm) (data not shown).…”

Characterization of Mycolic Acids in Total Fatty Acid Methyl Ester Fractions from <i>Mycobacterium</i> Species by High Resolution MALDI-TOFMS

“…Notably, peaks that we assigned as dicarboxy-MAs corresponding to wax-MAs lost their long carbon-chain secondary alcohols (C18-C22) in the process of methyl esteri cation. 30,31) e MALDI mass spectrum of the total FA ME fraction from M. smegmatis displayed a typical pattern of rapid growth that produced both even-and odd-numbered homologs; peaks corresponding to α′-MAs were observed in the range of m/z 900-1000, and peaks corresponding to α-and epoxy-MAs were observed in the range of m/z 1100-1300 (Fig. 4d).…”