H. Brade

α‐2→4‐Interlinked 3‐deoxy‐d‐manno‐octulosonic acid disaccharide

After mild acid hydrolysis, a disaccharide of 3-deoxy-D-manno-octulosonic acid (dOclA) was obtained from Re-mutant lipopolysaccharide of Salmonella minnesota, Salmonella godesberg, Proteus mirabilis, and Escherichia coli, and from the lipopolysaccharide of an S. minnesota Rb2 mutant. Combined gas-liquid chromatography/mass spectrometry of the reduced and permethylated derivatives indicated that the disaccharide is interlinked by a 2----4-glycosidic bond in all lipopolysaccharides tested. In addition, it was shown by gas-liquid chromatography of appropriate synthetic standards and a previously characterized alpha 2----4-linked dOclA disaccharide (derived from lipopolysaccharide of S. godesberg) that the non-reducing dOclA residue possesses the alpha configuration. In the case of lipopolysaccharide of S. minnesota Rb2 mutant, this result, together with earlier findings, suggests that it contains a linear dOclA trisaccharide of the sequence dOclA(alpha 2-4)dOclA. The results show that a dOclA(alpha 2-4)dOclA disaccharide represents a common architectural principle in enterobacterial lipopolysaccharides.

Bacterial lipopolysaccharides: relationship of structure and conformation to endotoxic activity, serological specificity and biological function.

Gram-negative bacteria express in their cell envelope various amphiphilic macromolecules among which the lipopolysaccharides (LPS) are of special significance for bacterial viability and the interaction of bacteria with host organisms. Together with phospholipids and proteins, lipopolysaccharides form the outer membrane of gram-negative bacteria. This outer membrane has an asymmetric architecture, i.e., lipopolysaccharides are located exclusively in the outer leaflet through which the bacterial cell interacts with its environment.

A method to detect 2-keto-3-deoxyoctanat and related compounds on pherograms and chromatograms

A variation of the thiobarbituric acid spray reagent to detect 2-keto-3-deoxyoctanat (KDO), KDO derivatives, 2-deoxysugars, and N-acetylneuraminic acid on pherograms and chromatograms is described. Using all reagents in organic solvents and developing the color at room temperature, accurate locations of the spots without spreading and a low background stain are achieved.

Molecular Aspects of the Chemistry and Biology of Endotoxin

Endotoxins are integral constituents of the outer membrane of gram-negative bacteria such as the Enterobacteriaceae, Neisseriaceae, and Chlamydiaceae (Luderitz et al. 1982). They participate in various physiological membrane functions essential for bacterial growth and survival. Endotoxins also represent the main heat-stable O-antigens of the bacteria and, thus, identify the multiplicity of serotypes. Finally, endotoxins are endowed with an overwhelming spectrum of biological activities, expressed either after injection into experimental animals, or in vitro. In fact, endotoxins have been recognized as playing an important role in the pathogenesis and manifestations of gram-negative infection, in general, and of septic shock, in particular. Thus, endotoxins are among the most potent agents capable of inducing local or generalized inflammatory reactions in both humans and experimental animals.

Lipopolysaccharide, die Endotoxine und O-Antigene gramnegativer Bakterien: Chemische Struktur, biologische Wirkung und serologische Eigenschaften

In nunmehr klassischen Arbeiten erkannte Richard Pfeiffer um die Jahrhundertwende, dab Lysate gramnegativer Bakterien (Vibrio cholerae, Escherichia coli, Bacteroides fragilis, Pseudomonas aeruginosa) im Tierversuch eine Reihe dramatischer biologischer Wirkungen hervorrufen. Zu diesen Wirkungen geh6ren Fieber, Blutdruckabfall, Diarrhoe, Verbrauchskoagulopathie, Schock und das Shwartzman-Sanarelli-Phfinomen. Pfeiffer nahm an, dab sich das aktive toxische Prinzip innerhalb der Bakterienzelle befindet, und nannte es daher Endotoxin (1). Spfiter wurde jedoch erkannt, dab Endotoxine auf der Bakterienoberflfiche lokalisiert sind und dab sie gemeinsam mit Proteinen und Phospholipiden die ~iuBere Membran gramnegativer Bakterien bilden. Als Oberflfichenmolekfile spielen Endotoxine eine wichtige Rolle bei der Auseinandersetzung h6herer Organismen mit gramnegativen Bakterien. Einerseits erkennt das Abwehrsystem im Verlauf einer Infektion eindringende Bakterien an ihren Endotoxin-Strukturen und reagiert mit der Bildung von Antik6rpern gegen solche Strukturen. Endotoxine stellen somit immunreaktive Oberflfichenantigene von Bakterien dar und werden deshalb auch als O-Antigene bezeichnet (2). Andererseits ist bekannt, dab aufgrund bakteriolytischer Prozesse freigesetzte Endotoxine als pathogenetische Faktoren bei gramnegativen Infektionen wirksam werden und entscheidend zu den Symptomen von Bakteri~imien und Sepsis beitragen (3).

Eine neue Methode zur quantitativen Endotoxinbestimmung mittels monoklonalem Antikörper WN1 222–5

The limulus amoebocyte lysate (LAL) test has been used to indicate the presence of endotoxin in plasma for many years [1]. Discordant results were explained by variations in preparation, lack of sensitivity but also specifity of the test assay [2].

The Chemical Structure of the Lipopolysaccharide of a Rc-Type Mutant of Proteus mirabilis Lacking 4-Amino-4-Deoxy- L Arabinose and Its Susceptibility towards Polymyxin B

The mutant Proteus mirabilis R4 (R4/028) was obtained from the wild-type strain P. mirabilis 028 (F87) by ultraviolet irradiation. Isolation of R4/028 lipopolysaccharide (LPS) and the partial elucidation of the glucose-heptose region as a trisaccharide: β-glucosyl-(1→ 3/4)-L-glycero-α -D-manno-heptosyl-(1 → 4/3)-L-glycero-α-D-manno-heptosyl-7-phosphate has already been described (11). The linkage region between d0clA and heptose, the terminal and side chain-linked d0clA, the substituents of the phosphate groups and the lipid A structure were the aim of this study. In addition, we examined the effect of polymyxin B on P. mirabilis R4/028 mutant, after finding that its LPS is lacking 4-amino-4-deoxy-L-arabinose (Ara4N). The presence of that unusual aminopentose has been suggested by Vaara et al., (15, 16) to be the reason for the resistance of P. mirabilis strains towards the action of polymyxin.