Dataset Information

Mapping the regioisomeric distribution of fatty acids in triacylglycerols by hybrid mass spectrometry.

ABSTRACT: This study describes the use of hybrid mass spectrometry for the mapping, identification, and semi-quantitation of triacylglycerol regioisomers in fats and oils. The identification was performed based on the accurate mass and fragmentation pattern obtained by data-dependent fragmentation. Quantitation was based on the high-resolution ion chromatograms, and relative proportion of sn-1(3)/sn-2 regioisomers was calculated based on generalized fragmentation models and the relative intensities observed in the product ion spectra. The key performance features of the developed method are inter-batch mass accuracy < 1 ppm (n = 10); lower limit of detection (triggering threshold) 0.1 ?g/ml (equivalent to 0.2 weight % in oil); lower limit of quantitation 0.2 ?g/ml (equivalent to 0.4 weight % in oil); peak area precision 6.5% at 2 ?g/ml concentration and 15% at 0.2 ?M concentration; inter-batch precision of fragment intensities < 1% (n = 10) independent of the investigated concentration; and averaged accuracy using the generic calibration 3.8% in the 1-10 ?g/ml range and varies between 1-23% depending on analytes. Inter-esterified fat, beef tallow, pork lard, and butter fat samples were used to show how well regioisomeric distribution of palmitic acid can be captured by this method.

SUBMITTER: Nagy K

PROVIDER: S-EPMC3520536 | biostudies-literature | 2013 Jan

REPOSITORIES: biostudies-literature

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Mapping the regioisomeric distribution of fatty acids in triacylglycerols by hybrid mass spectrometry.

Nagy Kornél K Sandoz Laurence L Destaillats Frédéric F Schafer Olivier O

Journal of lipid research 20121023 1

This study describes the use of hybrid mass spectrometry for the mapping, identification, and semi-quantitation of triacylglycerol regioisomers in fats and oils. The identification was performed based on the accurate mass and fragmentation pattern obtained by data-dependent fragmentation. Quantitation was based on the high-resolution ion chromatograms, and relative proportion of sn-1(3)/sn-2 regioisomers was calculated based on generalized fragmentation models and the relative intensities observ ...[more]

PMID: 23093552

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Project description:UNLABELLED:Bacterial interspecies interactions play clinically important roles in shaping microbial community composition. We observed that Corynebacterium spp. are overrepresented in children free of Streptococcus pneumoniae (pneumococcus), a common pediatric nasal colonizer and an important infectious agent. Corynebacterium accolens, a benign lipid-requiring species, inhibits pneumococcal growth during in vitro cocultivation on medium supplemented with human skin surface triacylglycerols (TAGs) that are likely present in the nostrils. This inhibition depends on LipS1, a TAG lipase necessary for C. accolens growth on TAGs such as triolein. We determined that C. accolens hydrolysis of triolein releases oleic acid, which inhibits pneumococcus, as do other free fatty acids (FFAs) that might be released by LipS1 from human skin surface TAGs. Our results support a model in which C. accolens hydrolyzes skin surface TAGS in vivo releasing antipneumococcal FFAs. These data indicate that C. accolens may play a beneficial role in sculpting the human microbiome. IMPORTANCE:Little is known about how harmless Corynebacterium species that colonize the human nose and skin might impact pathogen colonization and proliferation at these sites. We show that Corynebacterium accolens, a common benign nasal bacterium, modifies its local habitat in vitro as it inhibits growth of Streptococcus pneumoniae by releasing antibacterial free fatty acids from host skin surface triacylglycerols. We further identify the primary C. accolens lipase required for this activity. We postulate a model in which higher numbers of C. accolens cells deter/limit S. pneumoniae nostril colonization, which might partly explain why children without S. pneumoniae colonization have higher levels of nasal Corynebacterium. This work narrows the gap between descriptive studies and the needed in-depth understanding of the molecular mechanisms of microbe-microbe interactions that help shape the human microbiome. It also lays the foundation for future in vivo studies to determine whether habitat modification by C. accolens could be promoted to control pathogen colonization.

Dataset Information

Mapping the regioisomeric distribution of fatty acids in triacylglycerols by hybrid mass spectrometry.

Publications

Mapping the regioisomeric distribution of fatty acids in triacylglycerols by hybrid mass spectrometry.

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