Preparation of oligosaccharides by bacteriophage degradation of polysaccharides from Klebsiella serotypes K21 and K32

Preparation of Oligosaccharides by Degradation of Polysaccharides from Chinese Jujube and Its Biological Activity

This study examined the degradation of polysaccharides to oligosaccharides in Chinese jujube fruits. Using a response surface model, the degradation conditions of polysaccharides under acid hydrolysis and enzymatic hydrolysis were optimized in laboratory conditions. A degradation rate of 66.9% was obtained under optimum acid hydrolysis conditions: 0.6 mol/L hydrochloric acid, 3% substrate concentration, and 1 h reaction time. A degradation rate of 41.4% was obtained under optimum enzyme hydrolysis conditions: 4.0 mL cellulose solution (10 mg/mL), 0.3 mL substrate solution (20 mg/mL), 0.7 mL citric acid buffer solution (pH 5), and 7.3 h reaction time. Using the stimulation effect for strain J-4 intestinal probiotic proliferation, the biological activity of oligosaccharides was determined. The results showed that the oligosaccharides from enzyme hydrolysis encouraged intestinal probiotic proliferation.

Extracellular polysaccharide of Erwinia chrysanthemi Ech6

Many strains of Erwinia chrysanthemi, which are Gram-negative bacterial phytopathogens, produce copious amounts of extracellular polysaccharides. The extracellular polysaccharide from E. chrysanthemi pv. zeae strain SR 260, a phytopathogen of corn, is a branched-chain glucomannorhamnan of proven structure (Gray et al., Carbohydr. Res. 1993, 245, 271-287). The extracellular polysaccharide from E. chrysanthemi Ech6 is different, containing no rhamnose or mannose. It is composed of L-fucose, D-galactose, D-glucose and D-glucuronic acid in the ratio 2:2:1:1. The structure of the polysaccharide is as follows: [sequence: see text]

Structural elucidation of the capsular polysaccharide of E. coli serotype K47

The capsular polysaccharide from Escherichia coli K47 was investigated using mainly methylation analysis and 1H and 13C NMR spectroscopy and shown to have the following repeating unit: [Formula: see text]

Analysis of pyruvic acid acetal containing polysaccharides by methanolysis and reductive cleavage methods

The mass spectra of permethylated methyl 4,6-O-(1-carbomethoxyethylidene)-D-hexopyranoside and 1,5-anhydro-D-hexitol of glucose, galactose, and mannose and permethylated methyl 5,6-O-(1-carbomethoxyethylidene)-D-galactofuranoside and 1,4-anhydro-D-galactitol have been determined. The stability of each compound toward methanolysis and reductive cleavage is discussed. These techniques permit the identification of the acetalic linkages of pyruvic acid present in polysaccharides.

Preparation of branched hexasaccharides by the action of a viral lyase on Klebsiella K14 polysaccharide

Klebsiella K14 capsular polysaccharide was degraded by a bacteriophage-borne enzyme to afford oligosaccharides A-C which were studied by one- and two-dimensional n.m.r. spectroscopy. A and B were the repeating-unit hexasaccharide and pyruvylated hexasaccharide, respectively, while C was a dodecasaccharide. Each oligomer was terminated by a reducing mannose and a non-reducing 4-deoxy-alpha-L-threo-hex-4-enopyranosyluronic acid residue, indicating that the phage enzyme had cleaved the beta-D-Manp-(1----4)-beta-D-GlcpA linkages in the polysaccharide by a lyase, rather than the more common glycosidase, activity found with other Klebsiella bacteriophages. In this respect, the depolymerisation resembles those reported for the capsular polysaccharides of Klebsiella K5 and K64

Depolymerization of the capsular polysaccharide from Klebsiella K19 by the glycanase associated with particles of Klebsiella bacteriophage luminal diameter 19

The site of cleavage of the capsular polysaccharide from Klebsiella K19 by the endoglycanase associated with particles of Klebsiella bacteriophage luminal diameter 19 was determined. The specific cleavage of the bond Rhap-(1----2)-Rhap provided a series of oligosaccharides having rhamnose at the reducing end. The enzyme is thus an alpha-rhamnosidase. Structural studies on the oligomers confirmed the sequence of the repeating unit of the polysaccharide from K19. The 1H- and 13C-n.m.r. spectra of the homologous series of oligosaccharides corresponding to one, two, three, and four repeat-units exhibit important differences that denot variation of conformation with chain length. The bacteriophage acted on modified forms of K19 polysaccharide to provide a series of linear oligomers, and emphasized the essential role of the negative charge on the uronic acid in the action of the glycanase.

Identification of pyruvated monosaccharides in polysaccharides by gas-liquid chromatography mass spectrometry

Twelve bacterial polysaccharides of known structure containing a representative range of pyruvated monosaccharides, were methanolysed, trimethylsilylated, and analysed by g.l.c. and g.l.c.-m.s. Except for 3,4-O-(1-carboxyethylidene)-L-rhamnose, which was unusually labile, the pyruvic acid substituents were largely retained during methanolysis and the Me3Si derivatives of the resulting pyruvated methyl glycosides gave distinctive g.l.c. peaks with characteristic mass spectra. The pyranose rings of 4,6-O-(1-carboxyethylidene)-D-glucose, 4,6-O-(1-carboxyethylidene)-D-mannose, 4,6-O-(1-carboxyethylidene)-D-galactose, and 3,4-O-(1-carboxyethylidene)-D-galactose survived the methanolysis, but that of 2,3-O-(1-carboxyethylidene)-D-glucuronic acid was cleaved to give the methyl ester of 2,3-O-(1-carboxyethylidene)-aldehydo-D-glucuronic acid dimethyl acetal. In the case of 2,3-O-(1-carboxyethylidene)-D-galactose, cleavage of the pyranose ring was less complete; under the conditions used in these experiments two-thirds of the pyranose rings were intact while one-third were cleaved to give the methyl ester of 2,3-O-(1-carboxyethylidene)-aldehydo-D-galactose dimethyl acetal. A very small amount of 3,4-O-(1-carboxyethylidene)-L-rhamnose from one polysaccharide retained its pyruvic acid substituent after gentle methanolysis to give the methyl ester of 3,4-O-(1-carboxyethylidene)-aldehydo-L-rhamnose dimethyl acetal. Susceptibility to cleavage of the pyranose ring during methanolysis appears to be a property of pyruvated monosaccharides with trans-fused 1,3-dioxolane rings.

Novel oligosaccharides obtained by bacteriophage degradation of the polysaccharide from Klebsiella serotype K26

Bacteriophage phi 26 was used to depolymerize the polysaccharide of Klebsiella K26, yielding three oligosaccharides. The major product was the heptasaccharide repeating unit, with one of the minor products being the fourteen-sugar oligosaccharide corresponding to two repeating units. The other minor product was unusual since it was a hexasaccharide devoid of the terminal, pyruvate-containing galactose unit present in the side chain of the normal repeating unit. Phage phi 26 was shown to act as a beta-galactosidase, and hence it may have the ability to remove the terminal beta-galactose residue in the side chain.

Bacteriophage degradation of Klebsiella K44 polysaccharide: an n.m.r. study and chemical proof of the position of the acetate group

Bacteriophages (phi) have been used to degrade polysaccharides into oligosaccharides containing one or more of their repeating units. The capsular polysaccharide from Klebsiella K44 contains an acetate group, and n.m.r. spectroscopy and chemical methods have been employed to prove its linkage to O-6 of the 4-linked glucose residue. Phage phi 44 was shown to be an alpha-glucosidase not influenced by the acetate moiety and thus able to depolymerize the polysaccharide into pentasaccharide repeating units, some of which contained acetate on O-6 of the reducing glucose residue. The two oligosaccharides were studied by 1H- and 13C-n.m.r. spectroscopy, and their spectra were compared with those of the native and the deacetylated polysaccharide. 13C-n.m.r. was a useful tool for locating the 6-linked acetate, the position of which was confirmed by the method of temporary protection using methyl vinyl ether. The importance of using bacteriophages to obtain oligosaccharides is highlighted by the better results obtained with the oligosaccharide in comparison to the polysaccharide, both in n.m.r. spectroscopy and the temporary protection method.

Acylated oligosaccharides from Klebsiella K63 capsular polysaccharide: depolymerization by partial hydrolysis and by bacteriophage-borne enzymes

The extracellular polysaccharide from Klebsiella K63 is unique in having acetic and formic ester groups attached to the D-galactopyranosyluronic residues in the trisaccharide repeating-sequence. These O-acyl substituents are shown to be somewhat resistant to mild hydrolysis by both acid and alkali. Bacteriophage-induced depolymerization of the polysaccharide generated a series of acylated oligosaccharides comprising one, or more, repeating unit(s). By mild hydrolysis with acid, the same series of oligomers was released from the polysaccharide, together with the corresponding non-acylated compounds and the expected acylated and non-acylated aldobiouronic acids. A study of these oligosaccharides, as well as of a number of their related compounds, is described, with particular emphasis on the methods used to locate the formic and acetic ester groups. The location of the O-acyl substituents on the galactosyluronic residues was further supported by the results obtained from the high-resolution, 400-MHz, p.m.r. spectra and 13C-n.m.r. spectra of a number of the oligosaccharides.

Preparation of oligosaccharides by the action of bacteriophage-borne enzymes on Klebsiella capsular polysaccharides

Depolymerization of bacterial, capsular polysaccharides by viral enzymes provides a convenient method for preparing oligosaccharides that correspond to one or more repeating unit(s) of the polysaccharide. Previous methods used for purifying bacteriophage particles, and also the procedures employed in the isolation and purification of the oligomers generated by the bacteriophage action, have been so modified as to provide a more direct route to the degradation products. Improved techniques, both for the propagation of bacteriophage and for the isolation of the oligosaccharides formed, are reported. These simplified methods make possible the use of bacteriophages as convenient "reagents" for the preparation of oligosaccharides on a gram scale. The acid- and base-labile substituents present in certain of the polysaccharides examined were seemingly unaffected by the conditions used for depolymerization. The methods are illustrated by degradation of the capsular polysaccharides from Klebsiella serotypes K17, K36, K46, K60, K63, and K74