Lipopolysaccharides hydrolysis

Hydrolysis by 1% acetic acid for a period of time sufficient to liberate the lipid A gave this material as 10—202 by weight of the entire lipopolysaccharide. Hydrolysis under more-vigorous conditions, followed by analysis for various constituents, as displayed in Table I, showed all of the lipopolysaccharides to... 

A structural study on lipid A and the O-specific polysaccharide of the lipopoly-saccharide from a clinical isolate of Bacteroides vulgatus from a patient with Crohn s disease was conducted by Hashimoto and coworkers [39]. They separated two potent virulence factors, capsular polysaccharide (CPS) and lipopolysaccharide (LPS), from a clinical isolate of B. vulgatus and characterized the structure of CPS. Next, they elucidated the strucmres of O-antigen polysaccharide (OPS) and lipid A in the LPS. LPS was subjected to weak acid hydrolysis to produce the lipid A fraction and polysaccharide fraction. Lipid A was isolated by PLC, and its structure was determined by MS and NMR. 

The polysaccharide component of a lipopolysaccharide can be separated from the lipid component by selective hydrolysis of the glyco-sidic linkages of the 3-deoxy-D-manno-octulosonic acid residues connecting these two components. The conditions for the hydrolysis are mild, namely, 0.1 M acetic acid for 1.5 h at 100° (Ref. 18). Similar conditions, namely, M formic acid for 1 h at 100° or 0.05 M hydrogen chloride in methanol for 1 h at 85°, were used to split off the sialic acid residues from gangliosides.19,20... 

Structural studies on the oligosaccharide derivatives obtained by partial, acid hydrolysis of fully methylated polysaccharides often furnish valuable information on the positions at which the oligosaccharides were linked in the original polysaccharide. When the folly methylated Klebsiella O group 9 lipopolysaccharide,27 which contains D-galactopyranose and D-galactoforanose residues, was subjected to mild, acid hydrolysis, and the product reduced with lithium aluminum deuteride and remethylated with trideuteriomethyl iodide, a good yield of the disaccharide derivative 10 was obtained. 

The O-antigen polysaccharides of Klebsiella serotype 05 and Escherichia coli 08 were prepared by mild hydrolysis of the lipopolysaccharides. A bacteriophage enzyme hydrolyzed both polymers,3150 giving the trisaccharide /3-D-Man-(l - 2)-a-D-Man-(l -> 2)-D-Man. 

The lipid material precipitated upon mild acid treatment of the Boivin-extracted lipopolysaccharide is here termed a lipoidal precipitate. The fatty-acid profile (Table IV) of hydrolyzates of this material shows little variation between the seven lmmunotype strains. If the original lipopolysaccharides are first treated by phenol—water extraction, and the resultant materials then subjected to hydrolysis to release the lipid, the composition of the latter is significantly different it corresponds closely to the classic composition expected for lipid A. It is noteworthy that material extracted by the phenol—water (Westphal) method is rich in the Csaturated acid and in the hydroxy fatty acids having ten and twelve carbon atoms, whereas the and C g saturated acids present in the lipoidal precipitate, as prepared by the Boivin procedure, are absent or present at much lower levels in the lipid prepared by the Westphal procedure -9). It... 

Total fatty acids were liberated by subjecting Salmonella minnesota Re lipopolysaccharide (or free lipid A) to acidic (4 N HC1, 5 h, 100°C) followed by alkaline (1 N NaOH, 1 h, 100°C) hydrolysis. After extraction (chloroform), the free fatty acids were converted into their methyl esters (diazomethane) and analysed by combined gas-liquid chromatography/mass spectrometry. Alternatively, the fatty acids of lipid A are transesterified by treatment of lipopolysaccharide with methanolic HC1 (2 N HC1 in water-free CHaOH, 18 h, 85°C). By these procedures the following fatty acids were identified (in approximate amounts relative to 2 moles glucosamine) dodecanoic (12 0, 1.1 mole), tetradecanoic (14 0, 0.8 mole), hexadecanoic (16 0, 0.9 mole), 2-hydroxytetradecanoic (2-OH-l4 0, 0.1 mole), and 3-hydroxytetradecanoic acid (3-OH-14 0, 4 moles). In total, therefore, approximately 7 moles of fatty acids are present per mole of lipid A backbone. The stereochemistry of the hydroxylated fatty acids was determined by gas-liquid chromatography of their diastereomeric methoxyacyl-L-phenylethylamide derivatives (24). It was found that 2-hydroxyte-tradecanoic acid possesses the-Ts), and the predominating 3-hydroxytetradecanoic acid the (R) configuration. 

Despite the fact that many heptoses are by far less prominent in Nature than hexoses these monosaccharides are found both as metabolic intermediates, and as structural carbohydrates of bacterial cell walls.D-Sedoheptulose 7-phosphate is an important intermediate of the pentose cycle, and D-sedoheptulose 1,7-bisphosphate is present in plants as an intermediate of the dark phase of photosynthetic reactions. L-Glycero-D-manno-heptose was isolated from the oligosaccharides obtained by partial acid hydrolysis of the lipopolysaccharide from Escherichia coli K-12 strain W3100 [153] and Haemophilus influenzae [154]. Both L-glycero-D-wtanno-heptose and D-glycero-D-ma o-heptose were isolated from the lipopolysaccharide of Vibrio parahaemolyticus [155]. 

Occurrence. D-f/treo-Pentulose 5-phosphate (d-xylulose 5-phosphate) is an intermediate in the metabolism of xylose in bacteria, and is also formed from d-erythro-pentulose 5-phosphate in the presence of an epimerase.57 D- /m o-PcnLulose has been found in a lipopolysaccharide from Pseudomonas diminuta, from which it was obtained after hydrolysis by mild acetic acid as used to release lipid A.58 It was also found in the LPS of a Yersinia enterocolitica serologic variant.59... 

L-Xylulose is a constituent of the lipopolysaccharide from Yersinia enterocolitica serovar 0 10,65 from which it was obtained by mild acid hydrolysis and purification by paper chromatography. 

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