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  • 1
    ISSN: 1432-072X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary 1. The isolation and chemical characterization of the lipopolysaccharides (O-antigens) of 12 strains of the gram-negative photosynthetic bacterium Rhodopseudomonas palustris is described. Lipopolysaccharides (LPS) were extractable with phenol/water, however, the bulk of the LPS of all strains remained in the phenol phase and only trace amounts were found in the aqueous layer. The LPS was also extractable by a phenol/chloroform/petroleum ether mixture (PCP-method), recommended for lipophilic glycolipids. Neither incubation of living bacteria with EDTA nor with NaCl liberated appreciable amounts of LPS-protein-lipid conjugates from the cells. 2. All strains investigated were found to have galactose, mannose, heptose, 2-keto-3-deoxyoctonate (KDO), glucosamine, 6-deoxy-glucosamine (quinovosamine) and a recently identified sugar, a 2,3-diamino-2,3-dideoxyhexose, as common LPS constituents. The presence of additional sugars allowed the classification of the strains into three distinct chemotypes. Chemotype I contains 4-O-methyl-D-xylose, and several non-identified amphoteric amino sugars. Chemotype II contains 4-O-methyl-D-xylose, 3-O-methyl-6-deoxy-D-talose, 6-deoxy-talose, xylose and again some unidentified amphoteric amino sugars, which were different from those of chemotype I. In chemotype III xylose, glucose, rhamnose, galactosamine and 6-O-methyl-glucosamine were identified. The main fatty acid in the high molecular weight material from the phenol phase of phenol/water extracts of all strains is β-hydroxymyristic acid. In addition in all strains β-hydroxypalmitic, palmitic and stearic acids were found. It has still to be proven that all these fatty acids are LPS constituents. 3. Like enteric LPS the LPS of R. palustris can be split by mild acid hydrolysis in a lipid portion (lipid A) and the degraded polysaccharide. But contrary to enteric lipid A, the lipid A of R. palustris does not contain glucosamine, but has the 2,3-diamino-hexose as the only amino sugar constituent. The possible occurrence of a common R-core and the question if repeating units exist in the O-specific chains of R. palustris LPS are discussed. 4. In two strains small amounts of additional LPS, which differ in their chemical composition from the respective LPS of the phenol phase, were isolated from the aqueous phase.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 0372-7874
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Um sichere Werte für die Federkonstanten der N—O-Einfach-, Doppel- und Dreifach-Bindung zu erhalten, mußten Stoffe spektroskopiert werden, in denen diese Bindungen ungestört durch Mesomerie vorliegen. Als Vertreter der Einfach-Bindung wurde Trimethylaminoxyd und als Vertreter der Doppelbindung Nitrosoisopropylaceton aufgenommen. Für die Dreifach-Bindung wurden die bekannten Werte von Nitrosylperchlorat und Nitrosylschwefelsäure benutzt. Die erhaltenen Werte für fN—O = ∼4,5 bzw. fN=O = 11,4 · 105 Dyn/cm werden verglichen mit denen von Hydroxylamin, von Oximen, Alkylnitriten, Alkylnitraten und Halogenpikrinen und daraus Schlusse auf die N—O-Bindungen in diesen Stoffen gezogen. Die N—O-Bindungen werden den übrigen Bindungen der Elemente Kohlenstoff, Stickstoff und Sauerstoff gegenübergestellt.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    ISSN: 0044-8249
    Keywords: Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 263 (1950), S. 213-228 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Es werden die Raman-Spektren mitgeteilt von Dimethyl-, Methyläthyl-, Diäthyl-, Di-n-propyl-, Di-i-butyl- und Phenylmethyl-nitrosamin, außerdem von Nitrosophenylhydroxylamin (Kupferron). Zur Ausdeutung des Spektrums des einfachsten Vertreters, des Dimethylnitrosamins, wird eine Berechnung des Spektrums durchgeführt. Die darauf gegründete Zuordnung der beobachteten Frequenzen wird gestützt durch Lösungmittelbeeinflussung und durch den Vergleich mit den Spektren höherer Homologer und mit dem ähnlichen Nitrosohydroxylamin. Alle Ergebnisse bestätigen den weitgehenden mesomeren Ausgleich der beiden möglichen Grenzstrukturen. Weiterhin lassen sich detaillierte Aussagen über Änderungen der Bindekräfte durch Änderungen der Umgebung der Nitrosamin-Gruppe machen.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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