Better together – Relative retention time plus spectral matching improves automated glycan characterization using PGC-nLC-IT-ESI-MS/MS

Porous Graphitized Carbon nano-liquid chromatography tandem mass spectrometry (PGC-nLC-MS/MS) is a glycomics technique with the unique capacity to differentiate isobaric glycans. The lack of suitable software tools integrating chromatography and MS-information delivered by PGC-nLC-MS/MS has been limiting fast and robust glycan identification and quantitation. We report a LC-system-independent strategy called GlycoRRT that combines relative retention time (RRT) and negative ion fragment spectra analyses for isobaric structure-specific glycomics of PGC-nLC-MS/MS data. The GlycoRRT toolset is fully customizable and easily adaptable enabling semi-automated high-throughput structural assignments. The current library contains over 200 entries and their individual meta-data (MS instrumentation, experimental conditions, retention times, fragmentation profiles and glycan structural diagnostic ion features) relevant for reliable data analyses. The GlycoRRT workflow was employed to map the N- and O-glycome in blood group matched human plasma and urine as well as decipher Immunoglobulin (IgG) glycosylation features from 13 different animal species. We have also developed visualization tools to enable a consistent, reliable and reproducible analysis of large sets of multidimensional PGC-nLC-MS/MS glycomics data. This comprehensive glycan resource provides the glycan map of human and animal species, will serve as a reference in dissecting the role of glycans in host pathogen interaction and zoonotic disease transmission.

Abstract T P86: Lipid Profiling Reveals Galatosylceramide Increasing in Plasma of Atherosclerotic Stroke

The development and innovation of new technique in metabonomics research and its application in medicine provides important resolution in screening biomarkers and targets for further investigation. The metabonomics research has unique advantages of facility, objection and reliability compared with other -omics studies. Lipidomics research was development based on metabonomics and has supreme merits in study of lipids related disease. Method: The carotid arthrosclerosis patients with stroke suffered before were recruited in this research. The items of lipid related laboratory examinations of these patients are normal because of well controlling under drug-taken. The peripheral blood of these patients was drawn and the plasma was isolated after centrifugation. The lipids from plasma were extracted by the standard Folch method. Then the lipids samples were injected for lipid profile analysis by 2D QoF LC/MS. The qualitative differentiations of these lipids were based on their m/z value, characteristic of the compounds fragmentation, direct and relative retention time of each lipid class. On the establishment of the lipids identification, we validated this newly 2D QoF LC/MS method following these measurements including its calibration equations, low of the detection and relative standard deviation. Result: Compared with native subjects, 518 different types of lipids molecular from 17 classes were identified from plasma of atherosclerosis patients by the method of 2D QoF LC/MS; The galactosylceramide and glucoceramide were identified separately although they were same of molecular weight; We proved that the levels of galactosylceramide, rather than glucoceramide were increasing in atherosclerotic stroke patients. Conclusion: the increasing levels of galactosylceramide in plasma of atherosclerosis patients hint that the immune effects induced by lipids play an important role in atherosclerosis.