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See detailCell walls of Streptococcus pyogenes, type 14. C polysaccharide-peptidoglycan and G polysaccharide-peptidoglycan complexes
Munoz, E.; Ghuysen, Jean-Marie ULg; Heymann, H.

in Biochemistry (1967), 6(12), 3659-2670

About 20% of the organic phosphorus present in cell walls of Streptococcus pyogenes occurs as N-acetylmuramic acid 6-phosphate residues (50 mµequiv/mg of walls). These groups link about 10% of the ... [more ▼]

About 20% of the organic phosphorus present in cell walls of Streptococcus pyogenes occurs as N-acetylmuramic acid 6-phosphate residues (50 mµequiv/mg of walls). These groups link about 10% of the peptidoglycan subunits to a hitherto unrecognized polysaccharide. This polymer was isolated after degradation of trypsin-treated walls with Streptornyces F1 endo-N-acetylmuramidase; it consists of disaccharide peptide monomer (50 mµmoles/mg of walls) linked through a phosphodiester bridge to a polymer containing, per peptide monomer, five to six D-glucose residues, one glucosamine residue, and four to five unidentified hexosamine compounds. This polymer is designated as G polysaccharide. About 70% of the organically bound phosphorus in the cell walls (150 mµequiv/mg of walls) is present in the form of phosphodiester groups in the interior of the rhamnose-containing C polysaccharide. The linkages of the C-polysaccharide chains to the peptidoglycan are visualized as bridges of trirhamnose groupings, each bearing one β-linked N-acetylgluco-samine residue, bound at the reducing end, either directly or through an as yet undetermined intervening molecule, to C-4 of an N-acetylmuramic acid residue. After degradation of walls by endo-N-acetylmurami-dase, the C-polysaccharide chains remain bound to one N-acetylmuramic acid residue. This N-acetylmur-amic acid residue is substituted by one tetrapeptide monomer which in turn is linked via a di-L-alanyl bridge to another disaccharide peptide monomer. A structure for the cell walls of Streptococcus pyogenes is proposed that takes into account all of the recognized covalent linkages among the constituent polymers. [less ▲]

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See detailThe peptide N alpha-(L-alanyl-D-isoglutaminyl)-N epsilon-(D-isoasparaginyl)-L-lysyl-D-alanine and the disaccharide N-acetylglucosaminyl-beta-1,4-N-acetylmuramic acid in cell wall peptidoglycan of Streptococcus faecalis strain ATCC 9790
Ghuysen, Jean-Marie ULg; Bricas, E.; Leyh-Bouille, Martine et al

in Biochemistry (1967), 6(8), 2607-2619

A major portion of the cell wall peptidoglycan in Streptococcus faecalis is composed of the disaccharide tetrapeptide β-1,4-N-acetylglucosaminyl-N-acetylmuramyl-Nα-(L-alanyl-D-isoglutaminyl)-L-lysyl-D ... [more ▼]

A major portion of the cell wall peptidoglycan in Streptococcus faecalis is composed of the disaccharide tetrapeptide β-1,4-N-acetylglucosaminyl-N-acetylmuramyl-Nα-(L-alanyl-D-isoglutaminyl)-L-lysyl-D-alanine. The tetrapeptides are cross-linked through single D-isoasparaginyl residues extending from the C-terminal D-alanine of one tetrapeptide unit to the Nє-terminal L-lysine of another. It is the first time that the occurrence of an isoasparaginyl residue in a natural product has been described. The Streptomyces SA en-dopeptidase cleaves D-alanyl-D-isoasparaginyl linkages and is thus the first enzyme known to hydrolyze D-D peptide bonds. Treatment of the disaccharide Nα-( L-alanyl-D-isoglutaminyl)-N є-(D-isoasparaginyl)- L-lysil-D-alanine with 10 equiv of NaOH at 37° for 1 hr results in deamidation of the isoasparaginyl residue together with migration of the aspartyl-lysine peptide bond giving rise to a mixture of Nє-(β-aspartyl)- and N є-(α-aspartyl)lysyl peptides. Under the same alkaline treatment, the N-acetylmuramyl residue undergoes a lactyl elimination which results in the production of acyl peptides and a Morgan-Elson prochromogenic compound, without hydrolysis of the glycosidic linkage. This conversion, interpreted to be the result of a β elimination, also occurs in the other disaccharide peptide monomers previously isolated from Staphylococcus aureus, Micrococcus roseus, and Streptococcus pyogenes. [less ▲]

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See detailThe Cell Wall Peptidoglycan of Bacillus megaterium KM. I. Studies on the Stereochemistry of α,α'-Diaminopimelic Acid
Bricas, E.; Ghuysen, Jean-Marie ULg; Dezelee, P.

in Biochemistry (1967), 6(8), 2598-2607

α,α'-Diaminopimelic acid (DAP) occurs in the wall peptidoglycan of Bacillus megaterium KM predominantly in the form of its meso isomer (about 85% of the total residues) and, in minor amounts, in the form ... [more ▼]

α,α'-Diaminopimelic acid (DAP) occurs in the wall peptidoglycan of Bacillus megaterium KM predominantly in the form of its meso isomer (about 85% of the total residues) and, in minor amounts, in the form of its DD isomer. The amino groups on the L carbon of the meso-DAP residues are involved in peptide linkages to the glutamic acid residues. Most of the amino groups on the D carbon of the meso-DAP residues are free; some of them are substituted, thus probably serving to cross-link peptide subunits. These amino groups can be liberated by a Streptomyces endopeptidase. None of the DD-DAP residues have amino groups free. Moreover, these groups are not liberated by endopeptidase treatment. The peptidoglycan upon enzymatic degradation yields mainly two fractions. A major fraction is composed of disaccharide peptide monomer subunits containing only the meso isomer of DAP. A second minor fraction is composed of disaccharide peptide oligomers containing both meso and DD isomers of DAP. The meso-DAP residues isolated as monodinitrophenyl derivatives from both fractions have optical rotations and optical rotatory dispersions identical with that of synthetic monodinitrophenyl-meso-DAP obtained by dinitrophenylation of the amino group on the D carbon. The assignment of the DD configuration to the DAP residues which are not meso rests upon the optical rotatory properties of their bisdinitrophenyl derivatives. [less ▲]

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See detailSubstituents on the alpha-carboxyl group of D-glutamic acid in the peptidoglycan of several bacterial cell walls
Tipper, Donald J.; Katz, Walther; Strominger, Jack L. et al

in Biochemistry (1967), 6(3), 921-929

Several different carbohydrate-free peptides have been obtained from cell walls of Staphylococcus aureus and Arthrobacter crystallopoietes by degradation with lytic enzymes. They all contained one residue ... [more ▼]

Several different carbohydrate-free peptides have been obtained from cell walls of Staphylococcus aureus and Arthrobacter crystallopoietes by degradation with lytic enzymes. They all contained one residue of amide ammonia per repeating subunit. A peptide obtained from cell walls of Micrococcus lysodeikticus contained no ammonia but had a glycine residue with a free carboxyl group. It has been demonstrated by Edman degradation that both the amide ammonia in the former two cell walls and the COOH-terminal glycine in the latter are substituted on the α-carboxyl group of glutamic acid. Other features of the structures of these peptides are discussed. [less ▲]

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See detailAbondances anormales d'éléments dans les étoiles Ap
Renson, Pierre ULg

in Annales d'Astrophysique (1967), 30

From the data in Babcock's catalogue of magnetic stars and the data compiled by Bertaud, the proportion of Ap stars showing striking overabundancies of Si, Cr, Mn, Sr and Eu is deduced in terms of the ... [more ▼]

From the data in Babcock's catalogue of magnetic stars and the data compiled by Bertaud, the proportion of Ap stars showing striking overabundancies of Si, Cr, Mn, Sr and Eu is deduced in terms of the spectral type. However this correlation with the spectral class originates at least as much from variations of the visibility of the lines with temperature than from a real dependance of the abundance anomalies on the spectral type. The abundance factors in the Ap stars in regard to the normal ones increase in the average more or less exponentially with the atomic number or the atomic mass. [less ▲]

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See detailQuelques réflexions sur l'astrophysique moléculaire
Swings, Polydore ULg

in Hack, M. (Ed.) Modern astrophysics. A memorial to Otto Struve (1967)

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See detailThe emission lines in the ultraviolet region 3140-3500A of CH Cygni, and related problems
Swings, Jean-Pierre ULg; Swings, Polydore ULg

in Astrophysical Letters & Communications (1967), 1

The M6 semi-regular variable CH Cygni had an outburst in June 1967. The emission lines of the ultraviolet region λ< 3500 Å are described. General considerations on the importance of this region are ... [more ▼]

The M6 semi-regular variable CH Cygni had an outburst in June 1967. The emission lines of the ultraviolet region λ< 3500 Å are described. General considerations on the importance of this region are outlined. [less ▲]

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See detailUne recherche qui fera date : mesure du rendement de l'enseignement des mathématiques dans douze pays
de Landsheere, Gilbert ULg

in Nouvelle Revue Pédagogique (1967), 22(10), 588-600

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See detailPer una pedagogia della divergenza
de Landsheere, Gilbert ULg

in Scuola e Città (1967), 3

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See detailLes relations Sr-Ca dans les plagioclases des anorthosites du Rogaland méridional
Duchesne, Jean-Clair ULg

in Annales de la Société Géologique de Belgique (1967), 91

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See detailSur une forme monoclinique de l'ilvaite
Bartholomé, Paul; van de Plas, L.; Duchesne, Jean-Clair ULg

in Annales de la Société Géologique de Belgique (1967), 91

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See detailDosage du Sr et du Rb dans les feldspaths et roches acides. Applications à quelques roches standards
Duchesne, Jean-Clair ULg

in Annales de la Société Géologique de Belgique (1967), 90

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See detailAnthropologie culturelle et éducation comparée
de Landsheere, Gilbert ULg

in General education in a changing world : containing papers read before the Society at the second General Meeting Berlin 1965 (1967)

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See detailRecherche pédagogique et pratique scolaire
de Landsheere, Gilbert ULg

in Education : tribune libre d'information et de discussion pédagogiques (1967), (108), 9-12

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See detailComparaison du rendement de l'enseignement des mathématiques dans douze pays
de Landsheere, Gilbert ULg

in Education : tribune libre d'information et de discussion pédagogiques (1967), (106), 61-72

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See detailIntérêt et besoin d'accomplissement
de Landsheere, Gilbert ULg

in Education : tribune libre d'information et de discussion pédagogiques (1967), (105), 3-8

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See detailPour une nouvelle formation des maîtresses de jardin d'enfants
de Landsheere, Gilbert ULg

in Journées internationales de l'O.M.E.P. : assemblée mondiale de l'O.M.E.P., Paris-Unesco, 18-23 juillet 1966 (1967)

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See detailLes idées politiques et sociales de F.A. Diesterweg, à l'occasion du 100e anniversaire de sa mort
de Landsheere, Gilbert ULg

in Paedagogica Historica (1967), VII(1), 50-76

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See detailLa pédagogie expérimentale en Belgique
de Landsheere, Gilbert ULg

in International Review of Education (1967), 13(3), 298-305

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