Thin-layer chromatography of endotoxins, their derivatives and contaminants.

Thin-layer chromatographic (TLC) separation techniques were used to analyze the heterogeneity of various preparations which included smooth and rough endotoxins (ET), Lipid A precipitates and synthetic Lipid A samples and a novel cytotoxic bacterial lipid. Furthermore, carbohydrate-rich split products (PS) of ET were also separated on commercial silica-coated plates. Satisfactory results were obtained by two-dimensional TLC or by the combination of chromatography followed by high-voltage electrophoresis in the separation of PS of ET cleaved by mild acetic hydrolysis.

Cytotoxicity of a novel lipid-like bacterial product.

A highly cytotoxic, lipid-like compound was isolated from a Serratia marcescens strain currently under identification. We have named the compound DCX for its direct cytotoxic activity on various cell types in culture. DCX was purified by preparative thin layer chromatography from chloroform: methanol = 4:1 extracts of whole bacteria, and is chromatographically homogeneous.

Cu2+ is the active principle of an endogenous substance from porcine cerebral cortex which antagonizes the anticonvulsant effect of diazepam.

A boiled extract of porcine cerebral cortex was fractionated on Sephadex G-75 and LH-20 followed by paper chromatography of the active fraction having inhibitory activity towards [3H]GABA binding to rat brain synaptic membranes. A ninhydrin-negative substance migrating more quickly than authentic GABA was identified as a copper-GABA complex. The complex inhibited specific [3H]GABA binding (IC50 approximately equal to 1 microM) and antagonized the anticonvulsant effect exerted by intraamygdaloid injection of diazepam.

Heterogeneity in the carbohydrate moiety of the gamma-chain of bovine fibrinogen.

Two glycopeptides with identical amino acid sequence and carbohydrate composition, but of different sialic acid content were isolated from a combined tryptic-chymotryptic hydrolysate of bovine fibrinogen. Glycopeptide 1 contained two moles, glycopeptide 2 one mole of sialic acid. Both of them may have been derived from the gamma-polypeptide chain according to their amino acid sequence: Gln-Val-Glu-Asn-Lys.