Replacement of chloroform throughout glycosphingolipid isolation

Chloroform, the predominant constituent of solvents used for lipid extraction and chromatography, is believed to give rise to birth defects and serious damage to health, and may also be carcinogenic. Therefore, simple and successful methods have been developed to replace chloroform throughout the isolation of glycosphingolipids (GSLs) by less harmful solvents. Gangliosides of sheep brain (ganglio-series gangliosides GM1, GDla, GD1b and GT1b) and of lymphocyte-derived mouse hybridoma cells (namely GM3) were extracted with six different solvent mixtures. Chloroform:methanol:water (40:80:30, v/v/v) was employed as reference (solvent I). Combinations without chloroform were: n-propanol:water (40:10, v/v) (II), methylisobutylketone:methanol:water (40:80:30, v/v/v) (III), ethylacetate:methanol:water (40:72:28, v/v/v) (IV), methylacetate:methanol:water (40:72:28, v/v/v) (V) and petroleum ether:isopropanol:water (40:112:38, v/v/v) (VI). After extraction and dialysis, the weight of lipid extract as well as the content of sialic acid, gangliosides, sulphatides and phospholipids were determined. Quantitation of GSL yields in crude extracts obtained by the alternative solvent mixtures II to VI showed recoveries of brain gangliosides from nearly 67% up to 104% compared with the reference solvent I. Extraction of hybridoma cells by means of the alternative combinations without chloroform revealed at least the same and mostly better ganglioside yields in the range from 98% to 116% with regard to the reference solvent I. n-Propanol:water (II) and methylisobutylketone:methanol:water (III) were the recommended extractants for both tissues. Therefore, the methods described offer simple, less hazardous and successful strategies for GSL extraction in excellent yield without the need for using chloroform.

Different binding capacities of influenza A and Sendai viruses to gangliosides from human granulocytes

The structures of gangliosides from human granulocytes were elucidated by fast atom bombardment mass spectrometry and by gas chromatography/mass spectrometry as their partially methylated alditol acetates. In human granulocytes besides GM3 (II3Neu5Ac-LacCer), neolacto-series gangliosides (IV3Neu5Ac-nLcOse4Cer, IV6Neu5Ac-nLcOse4Cer and VI3Neu5Ac-nLcOse6Cer) containing C24:1, and to some extent C22:0; and C16:0 fatty acid in their respective ceramide portions, were identified as major components. In this study we demonstrate that gangliosides from human granulocytes, the second most abundant cells in peripheral blood, can serve as receptors for influenza viruses A/PR/8/34 (H1N1), A/X-31 (H3N2), and a parainfluenza virus Sendai virus (HNF1, Z-strain). Viruses were found to exhibit specific adhesion to terminal Neu5Ac alpha 2-3Gal and/or Neu5Ac alpha 2-6Gal sequences as well as depending on the chain length of ganglioside carbohydrate backbones from human granulocytes, these important effector cells which represent the first line of defence in immunologically mediated reactions.

Frequency and conditions of spontaneous plasmid transfer from E. coli to cultured mammalian cells

After exposing mammalian cell cultures to E. coli carrying the complete cDNA of poliovirus 1 in a plasmid, formation of polioviruses ensued even when no eukaryotic transcription signals were contained in the plasmid. The age of the bacteria greatly influenced the frequency of gene transfer, which was low if the bacteria were harvested in the exponential stage, reaching a maximum at the stationary phase and declining afterwards. Since the gene transfer was inhibited by cytochalasin B, phagocytosis of the bacteria could be a first step for the transfer; however, other mechanisms could not be ruled out.

Nondestructive detection of gangliosides with lipophilic fluorochromes and their employment for preparative high-performance thin-layer chromatography

A simple and effective procedure for the isolation and purification of gangliosides by preparative thin-layer chromatography is described. The method is based on nondestructive visualization of gangliosides on silica gel-precoated thin-layer chromatography plates by staining with uncharged lipophilic fluorochromes. Fluorescent dyes were added in low concentrations into the mobile phase (0.002%, w/v) without any interference of the ganglioside separation. After uv localization, the fluorescent zones were scraped off the plate and the silica gel was extracted with chloroform/methanol/water (30/60/8). In the following step fluorochromes were removed from gangliosides containing crude extracts by anion-exchange chromatography on DEAE-Sepharose. After desalting, impurities were removed by Iatrobeads chromatography. The method described offers an easy to handle and successful preparative thin-layer chromatography strategy to obtain pure gangliosides in microgram and miligram quantities.