The Use of Pyrolysis Gas Chromatography and Mass Spectroscopy in the Study of the Structure of Mycolic Acids

Etemadi, Abol-Hassan

doi:10.1093/chromsci/5.9.447

Cited by 49 publications

(29 citation statements)

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“…The anhydromycolate fragments in the mass spectrum of the mycolic esters from N. amarae N786 were significantly different (Table 6). Peaks corresponding to pyrolytic release of meroaldehydes and long-chain esters (Etemadi, 1967;Figs 3, 4) were observable in the mass spectra of all the mycolic esters analysed. The competing pathways (Fig.…”

Section: Lipid Analysesmentioning

confidence: 97%

Numerical and Chemical Classification of Nocardia amarae

et al. 1982

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~~Twenty-one strains of Nocardia amarae and marker cultures of Mycobacterium, Nocardia, R hodococcus and the 'aurantiaca' taxon were subjected to numerical phenetic analyses using 92 unit characters. The data were examined using the simple matching (SsM), Jaccard (S,) and pattern (D,) coefficients and clustering was achieved using the unweighted average linkage algorithm. Neither cluster nor aggregate cluster composition was markedly affected by the coefficient used or by test error, estimated at 1.5 %. The N. amarae strains formed a distinct and homogeneous cluster which showed its highest similarity to phena equated with Nocardia asteroides, Nocardia brasiliensis and Nocardia otitidis-caviarum. The nonhydroxylated fatty acid composition and overall size of the mycolic acids was similar to that found to be characteristic of Nocardia sensu stricto, though the long-chain in the 2-position of the my colic acids was relatively much richer in monounsaturated components. Nocardia amarae, in containing dihydrogenated menaquinones with nine isoprene units, is clearly distinguished from established representatives of Nocardia.

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Section: Lipid Analysesmentioning

confidence: 97%

Numerical and Chemical Classification of Nocardia amarae

et al. 1982

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“…The column was maintained at 300 "C for the analysis of the trimethylsilyl ether derivatives and at 180°C for GC of mycolic methyl esters (Etemadi, 1967). Electron impact (70 eV) mass spectra of methyl mycolates were determined on an AEI MS 902 instrument and isobutane chemical ionization spectra were determined on a VG ZAB HF instrument.…”

Section: E T H O D Smentioning

confidence: 99%

“…2). The peaks at m/z 51 1, 509 and Pyrolytic GC of methyl corynomycolates (Etemadi, 1967) gave methyl esters of C14 and c 1 6 fatty acids and C16, C1 8 : O and C18:1 aldehydes. Methyl corynomycolates were quantified by gas chromatographic analysis of the trimethylsilyl ether derivatives.…”

Section: Identlfication Of Mycolic Acidsmentioning

confidence: 99%

Occurrence of Corynomycolic Acids in Strains of Nocardia otitidis-caviarum

Pommier¹,

Michel²

1985

Microbiology

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“…The injector temperature was at 260 uC and the temperature separation program involved an increase from 100 to 300 uC, at the rate of 5 uC min 21 , followed by 10 min at 300 uC. For pyrolysis conditions, the injector temperature was increased to 290 uC (Etemadi, 1967a). Alternatively, a GC Varian 3800 apparatus coupled to a mass spectrometer Varian Saturn 2000 was used.…”

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confidence: 99%

A novel mycolic acid species defines two novel genera of the Actinobacteria, Hoyosella and Amycolicicoccus

et al. 2012

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A novel mycolic acid species defines two novel genera of the Actinobacteria, Hoyosella and Amycolicicoccus Corynebacterineae are characterized by the presence of long-chain lipids, notably mycolic acids (a-alkyl, b-hydroxy fatty acids), the structures of which are genus-specific. Mycolic acids from two environmental strains, Amycolicicoccus subflavus and Hoyosella altamirensis, were isolated and their structures were established using a combination of mass spectrometry analysis, 1 H-NMR spectroscopy and chemical degradations. The C 2 -C 3 cleavage of these C 30 -C 36 acids led to the formation of two fragments: saturated C 9 -C 11 acids, and saturated and unsaturated C 20 -C 25 aldehydes. Surprisingly, the fatty acids at the origin of the two fragments making up these mycolic acids were present in only minute amounts in the fatty acid pool. Moreover, the double bond in the main C 24 aldehyde fragment was located at position v16, whereas that found in the ethylenic fatty acids of the bacteria was at v9. These data question the biosynthesis of these new mycolic acids in terms of the nature of the precursors, chain elongation and desaturation. Nevertheless, they are consistent with the occurrence of the key genes of mycolic acid biosynthesis, including those encoding proteins of the fatty acid synthase II system, identified in the genome of A. subflavus. Altogether, while the presence of mycolic acids and analysis of their 16S rDNA sequences would suggest that these strains belong to the Mycobacteriaceae family, the originality of their structures reinforces the recent description of the novel genera Amycolicicoccus and Hoyosella. INTRODUCTIONThe suborder Corynebacterineae forms a large group of actinomycete species characterized by the presence of specific lipids, notably mycolic acids (a-alkyl, b-hydroxy long-chain fatty acids). The variability of their chain lengths and the complexity of their structures contribute to the definition of the genera, from the simplest corynomycolic acids of Corynebacterium to the most complex and species-specific mycolic acids of Mycobacterium, with intermediate chain-lengths in Rhodococcus, Nocardia and Gordonia (Barry et al., 1998). Recently two coccoidal strains have been isolated from environmental sources, Hoyosella altamirensis, from the Altamira cave in Spain, and Amycolicicoccus subflavus, from saline soil contaminated with crude oil in the Daqing Oilfield of eastern China (Jurado et al., 2009;Wang et al., 2010). By a polyphasic approach, the taxonomic position of the two species has been determined, i.e. Actinomycetales cell wall chemotype IV, menaquinones MK-8, diagnostic phosphatidylethanolamine and tuberculostearic acid. On the basis of 16S rRNA gene sequence analysis, the two species were shown to be most closely related to the genus Mycobacterium (95.6 % similarity with the Mycobacterium fallax type strain for Hoyosella, and 92.7-94.9 % similarity with Mycobacterium spp. for Amycolicicoccus). The two species differ from each other by their DNA G+C content, which is 49...

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The Use of Pyrolysis Gas Chromatography and Mass Spectroscopy in the Study of the Structure of Mycolic Acids

Cited by 49 publications

References 0 publications

Numerical and Chemical Classification of Nocardia amarae

Numerical and Chemical Classification of Nocardia amarae

Occurrence of Corynomycolic Acids in Strains of Nocardia otitidis-caviarum

A novel mycolic acid species defines two novel genera of the Actinobacteria, Hoyosella and Amycolicicoccus

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