Solid-phase biosynthesis on high performance thin-layer plates of blood group glycosphingolipids II

TLC blotting: application to microscale analysis of lipids and as a new approach to lipid-protein interaction

A simple method for the transfer of phospholipids and glycosphingolipids from a high-performance thin-layer chromatography (HPTLC) plate to a polyvinylidene difluoride (PVDF) membrane, called thin-layer chromatography (TLC) blotting, and its application in lipid research are described. Most of the lipids developed on the HPTLC plate are blotted quantitatively. Detection of the lipids on the membrane is done by chemical and immunological staining. This method makes it possible to purify individual lipid components separated on an HPTLC plate and to determine the structures of lipids in limited biological samples when combined with direct mass spectrometric analysis (TLC blotting/MS). A binding assay and the identification of ligands for microorganisms can be made using TLC blotting/MS. In addition, simple methods for the detection of enzymes on a substrate-immobilized PVDF membrane are described.

High-resolution thin-layer chromatography of gangliosides

In this review an updated overview of current improvements on thin-layer chromatography (TLC) of gangliosides over the past decade is provided. Basic general techniques and special advice is given for successful separation of glycosphingolipids. New approaches concerning continuous and multiple development, and several preparative TLC methods are also included. Emphasis is placed on TLC immunostaining and related techniques, i.e. practical applications of carbohydrate-specific antibodies, toxins and bacteria, viruses, lectins and eukaryotic cells. Thus, this review on ganglioside TLC summarizes its power as an analytical tool for a wide range of purposes.

Direct assay of glycosphingolipid glycosyltransferase activities on thin-layer chromatogram

A modified method for the determination of glycosphingolipid glycosyltransferase activity using high-performance thin-layer chromatographic (HPTLC) plates has been developed. An acceptor glycosphingolipid was chromatographed on an HPTLC plate and was incubated with an enzyme mixture and an appropriate radioactive sugar nucleotide. After incubation, the plate was washed with phosphate buffer and 2% Tween 80. The radiolabeled reaction product was scrapped off the plate and the radioactivity determined using a liquid scintillation counter or, alternatively, the plate was exposed to an X-ray film to reveal the radioactive product. We have used this assay method to determine the activities of rat brain cytidine 5'-monophosphate-N-acetylneuraminic acid: LacCer-, GM3-, GM1-, or GD3-sialyltransferases. This method is sensitive, fast, and reliable and is capable of assaying simultaneously the activities of glycosyltransferases with multiple acceptor specificity. It should be useful in monitoring the enzyme activities present in various column fractions during chromatographic fractionation of glycosyltransferases with different substrate specificities.

Blood group A glycolipid antigen biosynthesis: discrimination between biosynthesized and enzyme preparation derived blood group A antigen by mass spectrometry

A monofucosyl type 1 chain blood group A hexaglycosylceramide was biosynthesized in solution using the type 1 chain blood group H pentaglycosylceramide as precursor, a crude microsomal fraction prepared from the mucosa scraping of a blood group A pig small intestine as enzyme source, and uridine diphosphate-N-acetyl-(1-14C)galactosamine as sugar donor. The radioactive product was enriched using reversed-phase column chromatography and silica gel HPLC. The peak, as detected by a beta-flow scintillation counter, was collected, permethylated, and analyzed by mass spectrometry. Carbohydrate sequence ions were found, indicating the presence of both the biosynthesized and a native, non-14C-containing blood group A hexaglycosylceramide. The blood group A pig small intestinal mucosa used as the enzyme source contain blood group A hexaglycosylceramide as the predominant glycolipid. Therefore, it is concluded that the nonradioactive blood group A hexaglycosylceramide found after the biosynthesis is derived from the enzyme preparation.

A sensitive method to quantitate gangliosides of the gangliotetraose series directly on chromatograms using peroxidase conjugated cholera toxin

A method is described whereby ganglioside GM1 can be quantitated directly on thin-layer chromatograms using cholera toxin subunit B conjugated to horseradish peroxidase and visualized with chloronaphthol. Overlay and color development were performed after separating gangliosides on nano-TLC plates, and fixing with polyisobutylmethacrylate. Absolute quantitation was realized using a Shimadzu CS-9000 integrating spectrodensitometer, scanning at 580 nm. A correlation coefficient of 0.98 was obtained in a linear range of detection from 10(-11) to 10(-16) moles. Statistical analysis revealed good reproducibility and over 99% of the added gangliosides remained with the chromatogram during all overlay and washing procedures. By comparison, standard chemical visualization by resorcinol-HCl was linear in the nanomole range with a detection limit of only 10(-10) moles. Since the carbohydrate portion of gangliosides immobilized in this manner is susceptible to the action of enzymes including neuraminidase, this technique can be applied to all structures of the gangliotetraose series.

Enzyme-linked immunosorbent assay (ELISA)-based quantification and identification of in vitro enzyme-catalyzed glycosphingolipid synthesis and degradation products with carbohydrate sequence-specific monoclonal antibodies

A new method has been developed to monitor glycosyltransferase and glycosylhydrolase activities. Reaction product identification and quantification are accomplished simultaneously with an enzyme-linked immunosorbent assay (ELISA) using carbohydrate sequence-specific monoclonal antibodies. beta-Galactosyltransferase and alpha-galactosidase reactions were used to illustrate the salient features of the method. These include simple product identification and quantification, no detergent requirement, consumption of small amounts of reagents, and no use of radioisotopes. Furthermore, it is possible to measure substrate disappearance or product formation with this method. Enzyme characteristics such as Km, Vmax, divalent cation requirement, and pH optimum were investigated with this new method.

Structural aspects of blood group glycosphingolipids in the gastrointestinal tract

The epithelial cells of the gastrointestinal tract from different species show a very variable expression of blood group active glycosphingolipids. The core saccharide sequences are typical for the species as, for example, type 1 chains (Gal beta 1----3GlcNAc) are found in the small intestine of man, rat, and pig and type 2 chains (Gal beta 1----4GlcNAc) are found in the small intestine of dog, rabbit, and cat. The mouse is atypical with the ganglioseries as the major core saccharide of the small intestine. Blood group A determinants can be found in the small intestine of man, rat, dog, rabbit, and cat, and the blood group B determinant in man and rabbit. Studies on the blood group active glycosphingolipids along the gastrointestinal tract of rat have revealed a complex distribution. The glandular cells of the stomach and epithelial cells of the large intestine express blood group B active glycosphingolipids. The cores of these are the ganglioseries, and the isogloboseries in the stomach and the lacto- (type 1) and neolactoseries (type 2) in the large intestine. The type 2 component is only expressed as a difucosyl and the type 1 as a monofucosyl compound. The epithelial cells of the small intestine are devoid of blood group B glycolipids, but express blood group H structures of which some has a branched core saccharide. One rat strain is lacking blood group A structures in the small intestine, but another is converting the H precursors to blood group A compounds. Both these strains always express blood group A structures in the large intestine. The expression of blood group A glycosphingolipids in the small intestine is inherited as a dominant trait.

Detection of blood group type glycosphingolipid antigens on thin-layer plates using polyclonal antisera

The conditions for binding of antibodies to glycosphingolipids separated on a thin-layer plate have been optimized for polyclonal antisera. The method has a broad detection range with low background staining. Examples are shown for the detection of blood group A and B active glycosphingolipids.