Formation of ganglioside internal esters by treatment with trichloroacetic acid-phosphotungstic acid reagent

Bis(monoacylglycero)phosphate: a secondary storage lipid in the gangliosidoses

Bis(monoacylglycero)phosphate (BMP) is a negatively charged glycerophospholipid with an unusual sn-1;sn-1' structural configuration. BMP is primarily enriched in endosomal/lysosomal membranes. BMP is thought to play a role in glycosphingolipid degradation and cholesterol transport. Elevated BMP levels have been found in many lysosomal storage diseases (LSDs), suggesting an association with lysosomal storage material. The gangliosidoses are a group of neurodegenerative LSDs involving the accumulation of either GM1 or GM2 gangliosides resulting from inherited deficiencies in β-galactosidase or β-hexosaminidase, respectively. Little information is available on BMP levels in gangliosidosis brain tissue. Our results showed that the content of BMP in brain was significantly greater in humans and in animals (mice, cats, American black bears) with either GM1 or GM2 ganglioside storage diseases, than in brains of normal subjects. The storage of BMP and ganglioside GM2 in brain were reduced similarly following adeno-associated viral-mediated gene therapy in Sandhoff disease mice. We also found that C22:6, C18:0, and C18:1 were the predominant BMP fatty acid species in gangliosidosis brains. The results show that BMP accumulates as a secondary storage material in the brain of a broad range of mammals with gangliosidoses.

Interaction of soluble and membrane proteins with monolayers of glycosphingolipids

1. The interactions of four proteins (albumin, myelin basic protein, melittin and glycophorin) with eight neutral or acidic glycosphingolipids, including sulphatides and gangliosides, five zwitterionic or anionic phospholipids and some of their mixtures, were studied in lipid monolayers at the air/145 mM-NaCl interface. 2. In lipid-free interfaces, the surface pressure and surface potential reached by either soluble or integral membrane proteins did not reveal marked differences. 3. All the proteins studied showed interactions with each of the lipids but the maximal interactions were found for basic proteins with acidic glycosphingolipids. 4. Surface-potential measurements indicated that different dipolar organizations at the interface can be adopted by lipid-protein interactions showing the same value for surface free energy. 5. The individual surface properties of either the lipid of protein component are modified as a consequence of the lipid-protein interaction. 6. In mixed-lipid monolayers, the composition of the interface may affect the lipid-protein interactions in a non-proportional manner with respect to the relative amount of the individual lipid components.

Influence of trichloroacetic acid-phosphotungstic acid on the thin layer chromatographic mobility of gangliosides

Trichloroacetic acid (TCA)-phosphotungstic acid (PTA) precipitation has been used as a faster procedure than dialysis for the isolation of gangliosides, but the TCA-PTA treatment causes striking abnormalities in the thin layer chromatographic mobilities of the gangliosides. However, a normal chromatographic pattern can be restored by treating the precipitated gangliosides with the tetrasodium salt of ethylenediamine tetraacetic acid followed by dialysis. Hence, TCA-PTA treatment does not appear to cause artifacts or hydrolysis of the gangliosides.