Biomedical subjects
Publications and source records attributed to H Parolis.
The primary structure of the acidic capsular polysaccharide of Escherichia coli K57 was elucidated by methylation analysis and 1D- and 2D-n.m.r. spectroscopy. The repeating unit was identified as a linear tetrasaccharide having the structure shown. ----2)-beta-D-Ribf-(1----4)-beta-D-Galp-(1----3)-alpha-D-GlcpNAc-( 1----4)-alpha - D-GalpA-(1----.
The capsular polysaccharide of Escherichia coli K31 has been found by methylation analysis and n.m.r. spectroscopy to be based on the hexasaccharide shown. The sequence of the repeating unit was deduced from the combined results of beta-elimination, lithium-ethylenediamine degradation, and hydrogen-fluoride and selective hydrolyses. The nature of the anomeric linkages, established by chromic acid oxidation, was confirmed by 1H-coupled 13C-n.m.r. spectroscopy. Two dimensional n.m.r. studies on a low molecular weight polymer obtained by bacteriophage depolymerization are also reported. (formula; see text)
The capsular polysaccharide of Klebsiella K10 was investigated by methylation analysis and 1H-n.m.r. spectroscopy, and the deacetylated bacteriophage-degraded polysaccharide by 1D- and 2D-n.m.r. spectroscopy. The repeating unit was shown to be a branched hexasaccharide (see text). OAc substituents were located on the terminal and 2-linked galactopyranosyl residues by Prehm methylation of a low-molecular-weight fraction obtained by bacteriophage degradation.
The structure of the capsular polysaccharide from Escherichia coli O8:K8:H4 has been elucidated, using mainly methylation analysis, Smith degradation, and 1D- and 2D-n.m.r. spectroscopy. The polysaccharide, after removal of bound lipid, was found to be composed of repeating units of the linear tetrasaccharide. (sequence; see text)
The structure of the capsular polysaccharide from Escherichia coli O9:K55 (N 24c) has been studied, using methylation analysis, degradation by bacteriophage, and n.m.r. spectroscopy. Depolymerisation of the K55 polysaccharide, using the lyase enzyme borne by Klebsiella phi 5, yielded a tri- and a hexa-saccharide, analysis of which indicated the following repeating unit. (formula; see text) This structure differs from that for the repeating unit of the capsular polysaccharide of Klebsiella K5 only in the position of acetylation (position 2 of the glucose residue).
The acidic capsular polysaccharide isolated from Escherichia coli O9:K39:H9 was investigated, using n.m.r. spectroscopy, methylation analysis, uronic acid degradation of the native and methylated polysaccharides, and bacteriophage-associated enzyme degradation. The structure of the repeating unit, which is shown below, is identical to that reported for Klebsiella serotype-61 capsular polysaccharide. (formula; see text)
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
The primary structure of the acidic capsular polysaccharide isolated from Klebsiella serotype K22 has been investigated using methylation analysis, hydrolysis, bacteriophage-borne enzyme degradation, and n.m.r. spectroscopy. The repeating unit comprises the chain disaccharide----3)-beta-D-Galp-(1----4)-beta-D-Glcp-(1---- substituted by 4-O-[(S)-1-carboxyethyl]-beta-D-GlcpA-(1----6)-alpha-D-Glcp-(1---- at O-4 of the galactose. The galactose carries an O-acetyl group on position 6.
The structure of the repeating unit of the capsular polysaccharide from Escherichia coli serotype K36 has been established from the results of spectroscopic and chemical analyses of (a) P1, the tetrasaccharide obtained on depolymerisation of the polysaccharide with a bacteriophage-borne endo-galactosidase, (b) P1-alditol, and (c) the original polysaccharide. The repeating unit, which is identical to that reported for Klebsiella K57, has the following structure. (Formula: see text).
The structure of the capsular polysaccharide isolated from Klebsiella serotype K69 has been investigated by a combination of chemical and spectroscopic methods. The repeating structure of the deacetylated polysaccharide is shown to be of the "3 + 1 + 1" type, and it carries a 1-carboxyethylidene acetal at positions 4 and 6 of a terminal galactosyl group. The location of acetyl groups in the polysaccharide has not been established. The repeating unit of the deacetylated polysaccharide has the following structure. (Formula: see text).
The acidic capsular polysaccharide isolated from Escherichia coli O9:K9:H12 was investigated by using n.m.r. spectroscopy, methylation analysis, periodate oxidation, and bacteriophage-borne enzyme degradation. The polysaccharide, the structure of which is shown below, is the third E. coli capsular polysaccharide reported to contain neuraminic acid, the others being the K1 and K92 polysaccharides, and it is the first in the E. coli series shown to contain a 4-linked neuraminic acid unit. (formula; see text).
Methylation analysis and graded acid hydrolysis showed that the capsular polysaccharide of Klebsiella K39 is of the "5 + 1" type and that the repeating unit contains two nonequivalent residues of D-glucopyranosyluronic acid, one of which constitutes the branch point. A decision between two possible structures, in favor of that shown below, was reached by examination of the hexasaccharide obtained by depolymerization using phage luminal diameter 39, which possessed an endo-beta-D-glucosidase. Anomeric configurations were assigned by analysis of 1H- and 13C-n.m.r. spectroscopic data for the polysaccharide and oligosaccharides derived therefrom. The following structure is proposed for the Klebsiella K39 antigen: -3(Glc beta 1-4)GlcA beta 1-2Man alpha 1-4GlcA beta 1-2Man alpha 1-3Glc beta 1- The polysaccharide is the first in the Klebsiella genus thus far reported to contain two uronic acid residues per repeating unit.
The structure of the capsular polysaccharide from E. coli O9:K37 (A 84a) has been studied, using methylation analysis, Smith degradation, and graded acid hydrolysis. The configurations at the anomeric centres were assigned by 1H-n.m.r. spectroscopy of the polysaccharide and its derivatives and oligosaccharide fragments. The polysaccharide has the following trisaccharide repeating-unit which is unique in the E. coli series of capsular polysaccharides in possessing a 1-carboxyethylidene group as the sole acidic function. (Formula: see text) E. coli capsular polysaccharides have been classified into seventy-four serotypes. The structures of about twenty of these polysaccharides have been elucidated, one of which, K29, has been reported to contain a 1-carboxyethylidene group. In continuation of a programme aimed at establishing the structural basis for the serology and immunochemistry of the E. coli capsular antigens, we now report on the structure of the capsular polysaccharide from E. coli O9:K37.
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The structure of the capsular polysaccharide isolated from Klebsiella K68 bacteria has been elucidated by both chemical and spectroscopic methods. The structure is of the "3 + 1" type, similar in pattern to the structures of the polysaccharides of Klebsiella K11 and K57, having a single branch point on the uronic acid. The polysaccharide is shown to consist of the following repeating unit: (Formula: see text).
The structure of the repeating unit of the capsular polysaccharide from Klebsiella serotype K3 has been established from the results of n.m.r. (1H and 13C) spectroscopy and methylation analysis of P1, the pyruvic acetal-bearing pentasaccharide obtained on depolymerization of the polysaccharide with a bacteriophage-borne endogalactosidase, reduced deacetalated P1, and the native polysaccharide. The data permit the assignment of the following structure to the repeating unit: (formula see text)
The structure of the capsular polysaccharide isolated from Klebsiella serotype K14 has been investigated employing a combination of chemical and spectroscopic methods. The repeating structure is shown to be of the "4 + 1 + 1" type, and it carries a 1-carboxyethylidene acetal substituent at positions 4 and 6 of a terminal glucose residue. The polysaccharide is one of a group of only three Klebsiella polysaccharides that have been found to contain a galactofuranose residue in the repeating unit. The repeating unit has the following structure: (Formula: see text).
Bacteriophage phi 60 possesses an endoglucosidase that depolymerizes the capsular polysaccharide of Klebsiella K60 into a heptasaccharide having two single beta-D-glucopyranosyl side-chains. This bulky oligosaccharide may be used as a probe to examine the combining sites of immunoglobulins. The 1H- and 13C-n.m.r.-spectral data of the oligosaccharide are reported.