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Biomedical subjects

G Strecker

Publications and source records attributed to G Strecker.

At least 163 records · Page 9Linked to original sources
PubMed1980

Macular cherry-red spot and myoclonus syndrome. Juvenile form of sialidosis.

Macular cherry-red spot, myoclonus and progressive mental deterioration are described in a man of 16 years. Morphological examination of the liver, bone marrow and fibroblasts showed numerous vacuoles containing storage material in the cytoplasm of the cells. Twelve different oligosaccharides were isolated from urine and their structures were determined. All have N-acetylglucosamine in a reducing end and (2--3) and 2--6) neuraminic acid in the terminal position. This abnormal urinary oligosaccharide excretion is due to absence of (2--6) neuraminidase which was not detected in fibroblast culture. This case is discussed in relationship to other cases with macular cherry-red spot, myoclonus and oligosaccharide urinary excretion.

Adolescent↗
PubMed1980

Characterization of a novel endo-N-acetyl-beta-D-glucosaminidase from the culture filtrate of a basidiomycete (Sporotricum dimorphosporum), active on biantennary mono- and asialoglycoasparagines of the N-acetyllactosaminic type.

A novel endo-N-acetyl-beta-D-glucosaminidase has been characterized in a culture filtrate from a Basidiomycete. This enzyme hydrolyses biantennary monosialo and asialo-glycoasparagines of the N-acetyllactosaminic type. Endo-N-acetyl-beta-D-glucosaminidase from the Basidiomycete released from different glycoasparagines, beta-GlcNAc-(1 leads to 4)-N[14C] acetyl-Asn, alpha Fuc-(1 leads to 6)-beta-GlcNAc-(1 leads to 4)-N-[14C]acetyl-Asn and oligosaccharides which have been separated by paper and thin-layer chromatography. Determination of the radioactivity of the labeled fragments leads to the conclusion that the biantennary glycoasparagines of the N-acetyllactosaminic type are hydrolyzed after 1 h incubation at 37 degrees, to the extent of 15 per cent for the monosialo; 90 per cent for the asialo; 21 per cent for the asialo-monofucosylated, and 15 per cent for the asialo-difucosylated glycans. Tri- and tetraantennary asialo-glycans of the N-acetyllactosaminic type are not hydrolyzed by this enzyme.

Acetylglucosaminidase↗
PubMed1980

Phosphorylated oligosaccharides in lysosomal enzymes: identification of alpha-N-acetylglucosamine(1)phospho(6)mannose diester groups.

In human fibroblasts, the recognition of lysosomal enzymes by cell surface receptors is mediated by mannose 6-phosphate residues located on oligosaccharides that can be cleaved by endo-beta-N-acetylglucosaminidase H. About half of these oligosaccharides, as isolated from beta-hexosaminidase and cathepsin D secreted by human skin fibroblasts, are anionic. Most of these are resistant to alkaline phosphatase. The resistance is due to alpha-N-acetylglucosamine residues linked to mannose 6-phosphate by a phosphodiester bond. The major phosphorylated oligosaccharides contain one and two and possibly three phosphate groups blocked by N-acetylglucosamine. Besides the blocked phosphate groups these oligosaccharides contain a common inner core consisting of Man alpha 1,6-(Man alpha 1,3)Man alpha 1,6(Man alpha 1,3)Man beta GlcNAc and either one or two alpha 1,2-linked mannose residues.

Acetylglucosamine↗
PubMed1980

Physicochemical characteristics of Listeria specific antigen 2.

Listeria specific antigen 2 (Ag2) was purified to within 97% of homogeneity, with a high yield, using both gel filtration and polyacrylamide gel electrophoresis. Ag2 is a glycoprotein. Its isoelectric point is about 4.2. As determined by sodium dodecyl sulphate-polyacrylamid gel electrophoresis, its molecular weight in 16710 +/- 450. Ag2 may aggregate easily since it was previously found in gel filtration in a peak corresponding to a molecular weight of 160000. No enzyme activity has been found in Ag2.

Amino Acids↗
PubMed1980

An immunochemical study of the lymphocyte A, Atri system.

The anti-Atri lymphocytotoxic antibodies reacting only with 5.19% of A, ABH-secreting individuals have been tested by an inhibition assay with 19 oligosaccharidic structures carrying the A, B, H or Lewis structures. The inhibitions observed dissociate the A and H blood group substances from the Atri substance, and seem to indicate the role of fucosyl residues, particularly that of fucosyl alpha (1 leads to 3), which may be the immunodominant of the Atri substance.

ABO Blood-Group System↗
PubMed1980

Purification, immunochemical, and biologic characterization of the Schistosoma circulating M antigen.

Circulating M antigen, specific for genus Schistosoma, was previously described in serum, urine, patients' milk, and in serum and urine of animals infected by S. mansoni. The M antigen was thermostable and soluble in trichloroacetic acid. It was not hydrolyzed by protease, ribonuclease, amylase, or neuraminidase but destroyed by sodium metaperiodate. In the present study, we have purified the M ag by using trichloroacetic acid solubility, DEAE Sephadex, and immunoadsorption. The M ag showed a neutral electric charge, a m.w. heterogeneity, and was only stained by periodic acid-Schiff. The composition study revealed M ag was a glycoprotein with a polysaccharide moiety (63% of the molecules) particularly rich in galactose, fucose, glucosamine, and mannose, and with a high molecular ratio of serine and threonine. The presence of O-glycosidic linkage allowed M ag to be considered as a mucin or a mucus glycoprotein-like component. It was localized in the cell wall of the gut of adult worms.

Amino Acids↗
PubMed1979

2-Acetamidoglucal, a new metabolite isolated from the urine of a patient with sialuria.

A new metabolite, namely 2-acetamidoglucal, has been found in the urine of a patient with sialuria in addition to the metabolites N-acetylneuraminic acid, N-acetylmannosamine, N-acetylglucosamine and 2-deoxy-2,3-dehydro-N-acetylneuraminic acid reported earlier. the structure has been identified by mass spectrometry and 360 MHz proton nuclear magnetic resonance spectroscopy and verified by synthesis. All accumulated compounds fit into the metabolic pathway for the biosynthesis of CMP-N-acetylneuraminic acid. Sialuria is discussed in terms of a failure of regulation of UDP-N-acetylglucosamine 2-epimerase.

Acetylglucosamine↗
PubMed1979

Sialidosis, a new type of inborn disease.

We describe the biochemical findings concerning five different types of mucolipidosis which have been defined as sialidosis on the basis of the specific enzyme deficiency and the nature of the storage material.

Adolescent↗
PubMed1979

[Mucolipidosis II (I cell disease): a sialidosis?].

I cell disease is characterised by loss of lysosomal enzymes from fibroblasts with accumulation of the same enzymes in the surrounding fluid. The urine oligosaccharides are composed by sialyl-oligosaccharides with equal numbers of alpha (2--6) and alpha (2--3) neuraminic acid -beta-galactoside bonds. A defect in the alpha (2--6) and alpha (2--3) neuraminidase activity in leucocytes and fibroblasts has been demonstrated. This deficit is the primary abnormality in I cell disease and it can be compared to the partial enzyme deficiencies described particularly in Mucolipidosis type I.

Body Fluids↗
PubMed1978

[Prediction of glycan structures of human N-glycoproteins].

By adding the sequence beta-(1 leads to 4)-GlcNAc-beta-(1 leads to)-Asn or alpha Fuc-(1 leads to 6 or 3)-beta-(1 leads to 4)-GlcNAc-beta-(1 leads to)-Asn to the oligosaccharides isolated from human urines of mannosidosis, fucosidosis and sialidosis, we are able to reconstitute numerous structures of asparaginyl-glycans. We postulate i) that these structures which have not yet been characterized pre-exist in glycans of human glycoproteins, probably in the cytoplasm or/and the cell membrane; ii) that they are products of the action of endo-beta-N-acetyl-glucosaminidases which are protected because of the lack of exoglycosidases and accumulate in the cells, and then in the urine.

Carbohydrate Metabolism, Inborn Errors↗
PubMed1978

[Spatial conformation of human serotransferrin glycans].

The construction of molecular models for the human serotransferrin glycans shows that they present one compact section linked to the protein and constituted by the pentasaccharide alpha-Man-(1 leads to 3)-[alpha-Man-(1 leads to 6)]-beta-Man-(1 leads to 4)-beta-GlcNAc-(1 leads to 4)-beta-GlcNAc-(1 leads to)-Asn to which are attached two "antennae" consisting of the trisaccharide alpha-NANA-(2 leads to 6)-beta-Gal-(1 leads to 4)-beta-GlcNAc. The trisaccharide sequence beta-Man-(1 leads to 4)-beta-GlcNAc-(1 leads to 4)-beta-GlcNAc adopts a flat and rigid conformation, stabilised by hydrogen bonds. In contrast, the sequence alpha-NANA-(1 leads to 6)-beta-Gal-(1 leads to 4)-beta-GlcNAc-(1 leads to 2)-alpha-Man takes up a helical configuration. The two "antennae" can be disposed on the pentasaccharide core to give two possible configurations, one Y-shaped and the other T-shaped. In both cases, the general conformation of the glycans is perfectly compatible with their postulated role as a recognition signal.

Chemical Phenomena↗
PubMed1978

360-MHz 1H nuclear-magnetic-resonance spectroscopy of sialyl-oligosaccharides from patients with sialidosis (mucolipidosis I and II).

360-MHz proton nuclear magnetic resonance spectra were recorded of 10 sialyl-oligosaccharides isolated from urine of sialidosis patients. Their structures are related to the complex asparagine-linked glycan chains of glycoproteins. By correlation of these spectra and comparison with spectra of reference glycopeptides and sialyl-lactose isomers it was possible to assign all signals belonging to anomeric, mannose H-2, sialic acid H-3 and N-acetyl protons. The number of the consituting monosaccharide residues of the oligomers can be obtained by integration of the above-mentioned signals. The chemical shifts of the anomeric and mannose H-2 protons give information about the type of glycan structure (mono-, bi-, triantennary) and the presence of terminal sialic acid at each of the antennas. The chemical shifts of sialic acid H-3 protons are typical for sialic acid residues in 2 leads to 3 or 2 leads to 6 linkage to galactose.

Carbohydrates↗
PubMed1978

Structure of the three major fucosyl-glycoasparagines accumulating in the urine of a patient with fucosidosis.

Fifteen fucosyl-oligosaccharides and fucosyl-glycoasparagines have been isolated from the urine of a patient with fucosidosis. The structure of the three most abundant glycoasparagines are as follows: alpha-Fuc-(1 lead to 6)-beta-GlcNAc-Asn; alpha-Man-(1 leads to 6)-beta-Man-(1 leads to 4)-beta-GlcNAc-(1 lead to 4) [alpha-Fuc-(1 leads to 6)]-belta-GlcNAc-Asn; beta-Gal-(1 leads to 4) [alpha-Fuc-(1 lead to 3)] beta-GlcNAc-(1 leads to 2)-alpha-Man-(1 lead to 6)-beta-Man-(1 leads to 4)-beta-GlcNAc-(1 leads to 4) [alpha-Fuc-(1 leads to 6)] beta-GlcNAc-Asn. The structures are related to the class of fucosyl-glycoproteins (e.g.: IgG immunoglobulin, lactotransferrin and alpha 1-acid glycoprotein). The terminal sequence: beta-Gal-(1 leads to 4) [alph-Fuc-(1 leads to 3)] beta-GlcNAc-(1 leads to 2)-a-Man leads to R is novel for carbohydrate moieties in glycoproteins.

Carbohydrate Metabolism, Inborn Errors↗
PubMed1978

[Mucolipidosis type I. Sialidosis due to alpha-2-6-neuraminidase deficiency with neurological symptoms].

A case close to mucolipidosis I was observed and the description of this mucolipidosis has to be revised since there were initially some confusions with mannosidosis. Three types of abnormalities appear to be important in its distinction from the other types of oligosaccharidoses: presence on the fundus of a cherry-red spot; in the bone marrow, reticulo-histiocytic cells, whose central nucleus is surrounded by multiple optically empty droplets; very elective overload of the Kupffer cells. 3a neurological syndrome with cerebellar ataxia appears in the evolution. However, it is not present in our patient nor the electroencephalogram changes. This latter point does not authorize the definite identification of our case with Spranger and Wiedemann description of mucolipidosis I especially as the neuraminidase deficiencies are certainly heterogenous.

Child, Preschool↗