The structure of the plasmalogens of ox heart

A novel plasmal conjugate to glycerol and psychosine ("glyceroplasmalopsychosine"): isolation and characterization from bovine brain white matter

A novel plasmal conjugate of glycosphingolipid having cationic lipid properties was isolated from the white matter of bovine brain. Linkage analysis of galactosyl residue by methylation, liquid secondary ion, and electrospray ionization mass spectrometry of intact and methylated derivatives, and by (1)H- and (13)C-NMR spectroscopy, identified the structure unambiguously as an O-acetal conjugate of plasmal to the primary hydroxyl group of glycerol and to the 6-hydroxyl group of galactosyl residue of beta-galactosyl 1-->1 sphingosine (psychosine). This novel compound is hereby termed "glyceroplasmalopsychosine"; its structure is shown below (see text).

Incorporation of isobutyrate and valerate into cellular plasmalogen by Bacteroides succinogenes

Wegner, G. H. (University of Wisconsin, Madison) and E. M. Foster. Incorporation of isobutyrate and valerate into cellular plasmalogen by Bacteroides succinogenes. J. Bacteriol. 85:53-61. 1963.-Bacteroides succinogenes was found to require both a branched-chain volatile fatty acid (e.g., isobutyric) and a straight-chain acid (e.g., valeric) for growth. The organism used the acids as precursors for the synthesis of long-chain fatty acids and fatty aldehydes, which in turn were employed in the synthesis of phospholipid, mainly ethanolamine plasmalogen. Isobutyric acid was incorporated primarily into branched-chain C(14) and C(16) acids (tentatively identified as 12-methyl tridecanoic and 14-methyl pentadecanoic acids, respectively), and into fatty aldehydes. Valeric acid was used mainly for the synthesis of n-C(13) and n-C(15) fatty acids and fatty aldehydes. Apparently the two short-chain fatty acids were built up by the addition of two-carbon units to form the long-chain acids and aldehydes of the plasmalogen.

PHOSPHATIDYLETHANOLAMINE AND LYSOPHOSPHATIDYLETHANOLAMINE

Phosphatidylethanolamine and Lysophosphatidylethanolamine belong to a group of phospholipids generally termed cephalins. The phospholipids are universally distributed among living organisms and are thought to be essential components of cell membranes. From the quantities of lipoidal and protein material found in cell membranes (Danielli and Stein, 1956) together with surface tension and related studies (Danielli and Harvey, 1935; Danielli and Davson, 1935), the membranes are considered to consist of a bimolecular leaflet of lipids with a unimolecular layer of protein adsorbed onto the polar surface.

The course of investigation of the cephalin fraction has not been reviewed in recent years, and here is discussed the general scope of the work in this field, under the headings of preparation, structure, synthesis and physical properties.

Simple method for the analysis of glycerol enol ethers derived from plasmalogens in complex lipid mixtures and subsequent determination of the aldehydic components by gas chromatography-mass spectrometry

Glycerol enol ethers, obtained by the reduction of plasmalogens with lithium aluminum hydride, can be converted into glycerol alk-(1)-enyl ether bismethyl ethers with diazomethane in the presence of silica gel. Their mass spectra allow the position of the enol ether group in glycerol unit to be deduced. Branches in the aldehydic components of the glycerol alk-(1)-enyl ether bismethyl ethers can be identified unequivocally by preparation of the 2-alkyl-1,3-dithiolanes, desulphurization with Raney nickel and deuterium to hydrocarbons and subsequent analysis by gas chromatography-mass spectrometry.

Mutation of Bacillus firmus OF4 to duramycin resistance results in substantial replacement of membrane lipid phosphatidylethanolamine by its plasmalogen form

Mutant strains of alkalophilic Bacillus firmus OF4 that were selected for resistance to duramycin had greatly reduced levels of membrane diacylphosphatidylethanolamine, as had been found in studies of such mutants of Bacillus subtilis. In the B. firmus strains, however, substantial levels of plasmenylethanolamine were found. This is an unusual membrane component for an aerobic eubacterium, but the presence of trace amounts even in the wild type was confirmed in experiments with 32Pi-labeled growth medium. The membrane lipid composition of the duramycin-resistant strains had several other changes that also left alkalophilic growth unimpaired.

The role of the plasmalogen in the cross-reaction between group A streptococcus and human myocardium

Ethanol-soluble mycardial material which reacts with anti-streptococcal sera in a number of immunological tests has been isolated and identified as ethanolamine plasmalogen. The reactions of cardiac plasmalogen with antistreptococcal sera was specific and could be inhibited by streptococcus-derived materials. Guinea-pigs sensitized to streptococci gave positive skin reactions when challenged with myocardial plasmalogen. The pattern of the immunofluorescent staining given by antiplasmalogen sera was very much like that given by antistreptococcal sera. Nevertheless, the plasmalogen failed to compete for tissue-bound myocardial antigens when tried as an inhibitor of the immunofluorescent staining of myocardium either by antistreptococcal sera or by antiplasmalogen sera. A hypothesis of the role of the plasmalogen in the formation of complexes between streptococci and myocardium-derived material in the initiation of autoimmune processes is presented.

The chemical nature of the products obtained by the action of cabbage-leaf phospholipase D on lysolecithin: the structure of lysolecithin

1. Lysolecithin, prepared by the action of snake-venom phospholipase A on ovolecithin, when incubated with Savoy-cabbage phospholipase D, in the presence of Ca(2+) ions, gave two degradation products (designated A and B) in the form of their calcium salts. 2. These calcium salts were separated quantitatively by solvent fractionation and converted into the corresponding sodium salts. 3. Substance B proved to be a lysophosphatidic acid of conventional structure (1-monoacyl-l-3-glycerophosphoric acid). When the phosphate group was removed by means of prostatic acid phosphomonoesterase, a 1-monoglyceride was formed quantitatively. Alkaline hydrolysis gave the theoretical yield of l-3-glycerophosphate. 4. Substance A, on the other hand, had all the properties expected for a cyclic phosphate of a 1-monoglyceride. It was unaffected by phosphomonoesterase. On alkaline hydrolysis, the acyl group was removed and ring opening of the presumed cyclic phosphate group gave an approximately equimolar mixture of 2- and l-3-glycerophosphates. 5. The structures of substances A and B confirm lysolecithin as 1-monoacyl-l-3-glycerylphosphorylcholine.

THE ACYLATION OF MONOACYL-L-α-GLYCERYLPHOSPHORYLCHOLINE UNDER VARIOUS CONDITIONS

Monoacyl-L-α-GPC's (lysolecithins) were converted to their cadmium chloride complexes and acylated with myristoyl chloride in chloroform in the presence and in the absence of pyridine. Both preparations of the diacyl-L-α-GPC's were reacted with phospholipase A of Crotalus adamanteus venom, and the nature of the fatty acids released, as well as the lysolecithin fatty acids, was determined by gas-liquid chromatography. The compositions of the fatty acids were different in the two preparations. These findings could indicate that acyl migration occurs during the acylation of the lysolecithin cadmium chloride complexes both in the presence and absence of pyridine, or that phospholipase A does not invariably remove the acyl group attached to the β-position in lecithin. The nature and possible causes of these variations are discussed.