Mass spectrometric analysis of ceramide composition in mono-, di-, tri-, and tetraglycosylceramides from mouse kidney: an experimental model for uropathogenic Escherichia coli

Many bacteria have been shown to bind to the carbohydrate part of glycosphi ngolipids, but also the lipid moieties of receptor-active glycolipids are o f Importance, To investigate the chemistry of the ct ceramides of kidney gl ycolipids to which the uropathogenic Escherichia coli bind, different mass spectrometric techniques were utilized. First, a mixture of glycolipids iso lated from man and mice kidney was separated by thin-layer chromatography ( TLC) and scanned by direct desorption from the plate by fast atom bombardme nt mass spectrometry (TLC/FAB-MS). Second, the glycolipids were purified by preparative TLC and analyzed by negative-ion FAB-MS. After methylation, fu rther analyses were made with positive-ion FAB-MS, positive-ion electron io nization (EI)-MS, high-temperature capillary gas chromatography (GC/EI-MS) and positive-ion matrix-assisted laser desorption/ionization (MALDI)-MS. Th e ceramide compositions of the four glycolipids were determined using all t hese MS techniques and the reliability of the different methods for this ty pe of analyses is discussed. Comparison of the mouse kidney glycolipids wit h the corresponding glycolipids from human kidney showed the same degree of hydroxylation ceramides among mono- and disaccharide glycolipids, but a si gnificantly higher degree of hydroxylation among mouse kidney glycolipids w ith three and four sugar residues. This result might be of relevance for ti me binding of P-fimbriated E. coli to the urinary trace tissues. Copyright (C) 1999 John Wiley & Sons, Ltd.