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G Larson

Publications and source records attributed to G Larson.

108 records · Page 6Linked to original sources
PubMed1982

Chemical fingerprinting of non-acid glycosphingolipids in meconium of a human individual of blood group B Le(a-b+) and secretor.

In an attempt to elucidate blood group polymorphism systematically in human intestinal tissue, glycosphingolipids of meconia of single individuals have been studied. In this report we describe the major glycosphingolipids in meconium of a newborn typed as a B Le(a-b+) secretor. The glycolipids were analysed as four subfractions obtained after deacetylation of fractions from silicic acid column chromatography of the peracetylated total non-acid glycolipid extract. Chemical characterization (mass spectrometry and 1H-NMR spectroscopy of permethylated and LiA1H4-reduced permethylated derivatives) and immunological characterization (haemagglutination-inhibition of native glycolipids in the liposome form) revealed a very complex pattern of fucosyl-containing glycolipids, probably the result of several blood group glycosyltransferase activities. The major fucolipids, all based on lactotetraosylceramide, had a characteristic ceramide of mainly phytosphingosine and 2-hydroxy fatty acids with 16 and 20-24 carbon atoms.

ABO Blood-Group System↗
PubMed1982

Chemical fingerprinting of glycosphingolipids in meconium of a human blood group O Le(a-b+) secretor.

Studying blood group polymorphism, as expressed in intestinal tissue of single individuals, total non-acid glycosphingolipids of meconium of individual human newborns have been prepared. Silicic acid column chromatography of the acetylated derivatives were used for a stepwise separation into four groups of glycolipids from each individual meconium. By the combined use of mass spectrometry and NMR spectroscopy of permethylated and LiA1H4-reduced, permethylated derivatives and by immunology of the native fractions all the major glycolipids were identified, although in mixtures. The interest was focused on fucolipids known to be strictly regulated by the ABO, H, Le and Se genes. The fucosylated glycolipids of an O Le (a-b+) secretor child were dominated by blood group H-active and Lewis-active mon- and difucosyl compounds with 5-6 sugar residues and having a core lactotetraosyl structure. The lipophilic part was dominated by 2-hydroxy fatty acids with 16 and 20-24 carbon atoms bounds to either sphingosine of phytosphingosine.

ABO Blood-Group System↗
PubMed1981

Monoclonal antibodies directed against the human Leb blood group antigen.

Four monoclonal antibodies produced by hybridomas obtained from a mouse immunized with a human adenocarcinoma cell line SW1116 (Koprowski, H., Steplewski, Z., Mitchell, K., Herlyn, M., Herlyn, D., and Fuhrer, P. (1979) Somatic Cell Genet. 5, 957-972) are directed against the Leb antigen of the human Lewis blood group system. Their specificities were established by binding studies using purified Leb-active ceramide hexasaccharide and by hapten inhibition studies involving oligosaccharides obtained from human milk.

Antibodies, Monoclonal↗
PubMed1981

Molecular characterization of cell surface antigens of fetal tissue. Detailed analysis of glycosphingolipids of meconium of a human O Le(a--b+) secretor.

The glycosphingolipids of meconium of a human O Le(a--b+) secretor have been subjected to structural and immunological characterization. Mass spectrometry, proton NMR spectroscopy, and gas-liquid chromatography were used for chemical analyses, and haemagglutination-inhibition for immunological characterization. The great amounts of glycolipids present also facilitated the analyses of minor species constituting only 1% or less of the total weight of the non-acid glycolipids. Glucosylceramide and galactosylceramide were the dominating glycolipids comprising 15 and 30%, respectively, of the total weight. The diglycosylceramides found were lactosylceramide and digalactosylceramide. The globo series was represented by globotriaosylceramide, small amounts of globotetraosylceramide, part of which had ceramide of phytosphingosine and hydroxy fatty acid, and a minor species of monofucosyl hexaglycosylceramide with an inner globotetraose oligosaccharide. No Forssman or Forssman-like antigen was found. The lacto series, quantitatively approximately 30% of the total weight, was mainly represented by lactotetraosylceramide and H-active, Lea-active, and Leb-active glycolipids with 5-6 sugars based on lactotetraosylceramide. Minor species having 0-3 fucoses in their carbohydrate chains and carrying up to 11 sugar residues were also identified. Great amounts of free ceramides were also found to be typical for this tissue.

ABO Blood-Group System↗
PubMed1980

Blood group type glycosphingolipids of human cord blood erythrocytes.

The non-acid glycosphingolipids of cord blood erythrocytes, pooled from blood groups O and A respectively, were characterized by mass spectrometry in combination with immunologic and thin-layer chromatographic analyses. The glycosphingolipid pattern was compared to that of adult erythrocytes. Just as for adult blood, the major glycosphingolipid species were lactosylceramide and globotetraosylceramide (globoside). The triglycosylceramide fraction was quantitatively smaller in cord red blood cells and was also enriched in a triglycosylceramide with a terminal hexosamine, as conclusively shown by mass spectrometry. The amount of blood group A and H active glycosphingolipids appeared to be less in cord blood cells compared to adult cells was glycolipids with longer, probably branched chain structures were not detected. In contrast, increased amounts of penta- and hexaglycosylceramides lacking fucose and possibly being biosynthetic precursor substances to the ordinary blood group A and H glycosphingolipids were found typical for cord blood cells.

ABO Blood-Group System↗
PubMed1979

Structural characterization of lactotetraosylceramide, a novel glycosphingolipid isolated from human meconium.

In the course of work on a systematic structural mapping of nonacid glycosphingolipids of human meconia, special attention was given to a major component preliminarily identified as an isomer of neolactotetraosylceramide (paragloboside). This component was isolated in its pure form from meconium of a blood group O individual and subjected to detailed structural analyses, using mass spectrometry and proton NMR spectroscopy on intact permethylated and permethylated-reduced (LiAlH4) derivatives, and gas liquid chromatography on degradational products of native, permethylated, and permethylated-reduced derivatives. The isolated compound was conclusively shown to have the structure Galp beta 1 yields 3GlcNAcp beta 1 yields 3Galp beta 1 yields 4Glcp beta 1 yields 1Cer, and is thus identified as lactotetraosylceramide. The major fatty acids were 2-hydroxy fatty acids with 16 and 20 to 24 carbon atoms, and the bases were sphingosine and phytosphingosine. This glycolipid, although not isolated and structurally characterized before, has long been thought of as a precursor substance of the Lewis active glycolipids and of ABH-active glycolipids with a type 1 saccharide chain.

Carbohydrate Sequence↗
PubMed1977

A study of the redox potentials and electron transfer rates of several naturally occurring and synthetic iron porphyrins in DMF.

The reduction potentials and formal electron transfer rate constants of several iron porphyrins were measured in DMF by the technique of cyclic voltammetry. The ease of each reduction was found to be a function of porphyrin ring basicity and was dependent on the type of electrode reaction. Greatest effects of ring basicity were observed for pi anion radical formation whil smaller effects were obtained for reactions involving the central metal. Electron transfer rate constants for the ferric-ferrous reaction also varied with ring basicity and paralled trends in the redox potentials, that is, the most basic porphyrin yielded the most difficult reduction, both kinetically and thermo-dynamically, while the least basic prophyrin yielded the most facile kinetic and thermodynamic reduction. Based on this data a mechanism of ferric-ferrous electron transfer involving transfer via the pi ring system is proposed.

Chemical Phenomena↗
PubMed1975

Fatty acid and aldehyde composition of major phospholipids in salt gland of marine birds and spiny dogfish.

The lipophilic components of choline phosphoglycerides and ethanolamine phosphoglycerides obtained from the salt gland of herring gull and eider duck and from the rectal gland of spiny dogfish were investigated by means of thin-layer chromatography, gas chromatography, and gas chromatography-mass spectrometry. All phospholipids analyzed were shown to contain small amounts of plasmalogens, and mainly C16, C18, and C18:1 aldehyde was detected. The fatty acids were composed of saturated, unsaturated, straight chain, and branched chain types, ranging between 14-22 carbon atoms. The lipophilic composition of the rectal gland phospholipids showed a higher degree of unsaturation and the presence of more branched chain fatty acids than that of the birds, possibly related to body temperature.

Aldehydes↗
PubMedDate not supplied

A test for intron function in the yeast actin gene.

Many eukaryotic genes contain intervening sequences (IVS), but the rationale for their existence remains a mystery. Previous studies done in our laboratory demonstrated that the intron in a yeast tRNATyr gene, SUP6, does have a function. We used the same approach to determine the role of introns in nuclear genes encoding messenger RNAs. A single actin gene with one intron exists in Saccharomyces cerevisiae. The level of actin in yeast appears to be crucial to viability: either too much or too little actin inhibits growth. Therefore, small effects on synthesis of actin protein resulting from the removal of the actin gene intron would be expected to cause measurable changes in cell growth. In the present study, an intron-deleted actin gene was constructed in vitro and was used to replace the single resident actin gene in a haploid strain. Analysis of the cells carrying the intron-deleted actin gene shows that the intervening sequence is not essential for actin gene expression.

Actins↗