Structural characterization of the antigenic capsular polysaccharide and lipopolysaccharide O-chain produced by Actinobacillus pleuropneumoniae serotype 15.

The specific capsular polysaccharide produced by Actinobacillus pleuropneumoniae serotype 15 was determined to be a high-molecular-mass polymer having [alpha]D + 69 degrees (water) and composed of a linear backbone of phosphate diester linked disaccharide units of 2-acetamido-2-deoxy-D-glucose (D-GlcNAc) and 2-acetamido-2-deoxy-D-galactose (D-GalNAc) residues (1:1). Thirty percent of the D-GalNAc residues were substituted at O-4 by beta-D-galactopyranose (beta-D-Galp) residues. Through the application of chemical and NMR methods, the capsule, which defines the serotype specificity of the bacterium, was found to have the structure [structure: see text]. The O-polysaccharide (O-PS) component of the A. pleuro pneumoniae serotype 15 lipopolysaccharide (LPS) was characterized as a linear unbranched polymer of repeating pentasaccharide units composed of D-glucose (2 parts) and D-galactose (3 parts), shown to have the structure [structure: see text]. The O-PS was chemically identical with the O-antigen previously identified in the LPSs produced by A. pleuro pneumoniae serotypes 3 and 8.     

The structure of the rough-type lipopolysaccharide from Shewanella oneidensis MR-1, containing 8-amino-8-deoxy-Kdo and an open-chain form of 2-acetamido-2-deoxy-D-galactose

The LPS from Shewanella oneidensis strain MR-1 was analysed by chemical methods and by NMR spectroscopy and mass spectrometry. The LPS contained no polysaccharide O-chain, and its carbohydrate backbone had the following structure: (1S)-GalNAco-(1-->4,6)-alpha-Gal-(1-->6)-alpha-Gal-(1-->3)-alpha-Gal-(1-P-3)-alpha-DDHep-(1-->5)-alpha-8-aminoKdo4R-(2-->6)-beta-GlcN4P-(1-->6)-alpha-GlcN1P, where R is P or EtNPP. There are several novel aspects to this LPS. It contains a novel linking unit between the core polysaccharide and lipid A moieties, namely 8-amino-3,8-dideoxy-D-manno-octulosonic acid (8-aminoKdo) and a residue of 2-acetamido-2-deoxy-D-galactose (N-acetylgalactosamine, GalNAco) in an open-chain form, linked as cyclic acetal to O-4 and O-6 of D-galactopyranose. The structure contains a phosphodiester linkage between the alpha-D-galactopyranose and D-glycero-D-manno-heptose (DDHep) residues.     

Structural characterization of the O-polysaccharide antigen of Edwardsiella tarda MT 108

Edwardsiella tarda, a Gram-negative bacterium, is an important cause of hemorrhagic septicemia in fish and also of gastro- and extraintestinal infections in humans. The lipopolysaccharide produced by the fish pathogenic strain E. tarda MT 108 was isolated and the structure of its antigenic O-polysaccharide component determined by the application of chemical analyses, high-resolution 1D and 2D nuclear magnetic resonance spectroscopy, and mass spectrometry. The polysaccharide was found to be a polymer of a repeating pentasaccharide unit composed of 2-acetamido-2-deoxy-D-glucose (D-GlcNAc), 2-acetamido-2-deoxy-D-galactose (D-GalNAc), D-galactose (D-Gal), L-rhamnose (L-Rha), D-galacturonic acid (D-GalA) and (2S,3R)-threonine (1:1:1:1:1:1) having the structure: [structure: see text].     

Structural analysis of the carbohydrate backbone of Vibrio parahaemolyticus O2 lipopolysaccharides

A structural investigation has been carried out on the carbohydrate backbone of Vibrio parahaemolyticus O2 lipopolysaccharides (LPS) isolated by dephosphorylation, O-deacylation and N-deacylation. The carbohydrate backbone is a short-chain saccharide consisting of nine monosaccharide units i.e., 1 mol each of D-galactose (Gal), D-glucose (Glc), D-glucuronic acid (GlcA), L-glycero-D-manno-heptose (L,D-Hep), D-glycero-D-manno-heptose (D,D-Hep), 3-deoxy-D-manno-oct-2-ulosonic acid (Kdo), 5,7-diacetamido-3,5,7,9-tetradeoxy-D-glycero-D-galacto-non-2-ulosonic acid (NonlA), and 2 mol of 2-amino-2-deoxy-D-glucose (D-glucosamine, GlcN). Based on the data obtained by NMR spectroscopy, fast-atom bombardment mass spectrometry (FABMS) and methylation analysis, a structure was elucidated for the carbohydrate backbone of O2 LPS. In the native O2 LPS, the 2-amino-2-deoxy-D-glucitol (GlcN-ol) at the reducing end of the nonasaccharide is present as GlcN. The lipid A backbone is a beta-D-GlcN-(1-->6)-D-GlcN disaccharide as is the case for many Gram-negative bacterial LPS. The lipid A proximal Kdo is substituted by the distal part of the carbohydrate chain at position-5. In the native O2 LPS, D-galacturonic acid, which is liberated from LPS by mild acid treatment or by dephosphorylation in hydrofluoric acid, is present although its binding position is unknown at present.     

Complex O-acetylation in non-typeable Haemophilus influenzae lipopolysaccharide: evidence for a novel site of O-acetylation

The structure of the lipopolysaccharide (LPS) of non-typeable Haemophilus influenzae strain 723 has been elucidated using NMR spectroscopy and electrospray ionization mass spectrometry (ESI-MS) on O-deacylated LPS and core oligosaccharide material (OS), as well as ESI-MSn on permethylated dephosphorylated OS. It was found that the LPS contains the common structural element of H. influenzae, l-alpha-D-Hepp-(1-->2)-[PEtn-->6]-l-alpha-D-Hepp-(1-->3)-[beta-D-Glcp-(1-->4)]-l-alpha-D-Hepp-(1-->5)-[PPEtn-->4]-alpha-Kdo-(2-->6)-Lipid A, in which the beta-D-Glcp residue (GlcI) is substituted by phosphocholine at O-6 and the distal heptose residue (HepIII) by PEtn at O-3, respectively. In a subpopulation of glycoforms O-2 of HepIII was substituted by beta-D-Galp-(1-->4)-beta-D-Glcp-(1--> or beta-D-Glcp-(1-->. Considerable heterogeneity of the LPS was due to the extent of substitution by O-acetyl groups (Ac) and ester-linked glycine of the core oligosaccharide. The location for glycine was found to be at Kdo. Prominent acetylation sites were found to be at GlcI, HepIII, and the proximal heptose (HepI) residue of the triheptosyl moiety. Moreover, GlcI was acetylated at O-3 and/or O-4 and HepI was acetylated at O-2 as evidenced by capillary electrophoresis ESI-MSn in combination with NMR analyses. This is the first study to show that an acetyl group can substitute HepI of the inner-core region of H. influenzae LPS.     

The structure of the core region of the lipopolysaccharide from Shewanella algae BrY, containing 8-amino-3,8-dideoxy-D-manno-oct-2-ulosonic acid

The structure of the carbohydrate backbone of the lipid A-core region of the LPS from Shewanella algae strain BrY was analysed. The LPS was N,O-deacylated to give three products, which were isolated and studied by chemical methods, NMR and mass spectrometry: [Carbohydrate structures: see text]. All monosaccharides except L-rhamnose had the D-configuration. This LPS presents a second example (after S. oneidensis) of the structure with a novel linking unit between the core and lipid A moieties, 8-amino-3,8-dideoxy-D-manno-oct-2-ulosonic acid (8-amino-Kdo).     

Structural and serological studies of the O-antigen of Proteus mirabilis O-9

The following structure of the O-polysaccharide (O-antigen) of the lipopolysaccharide of Proteus mirabilis O-9 was determined by NMR spectroscopy, including 2D 1H,(1)H COSY, TOCSY, ROESY, and 1H,(13)C HMQC experiments, along with chemical methods: [chemical structure: see text] where the degree of O-acetylation is approximately 70%. Immunochemical studies using rabbit polyclonal anti-Proteus mirabilis O-9 serum showed the importance of the O-acetyl groups in manifesting the serological specificity of the O-9 antigen. Anti-P. mirabilis O-9 cross-reacted with the lipopolysaccharides (LPS) of P. vulgaris O-25 and Proteus penneri 14, which could be accounted for by a structural similarity of their O-polysaccharides.     

C3 binds preferentially to long-chain lipopolysaccharide during alternative pathway activation by Salmonella montevideo

We studied the population of LPS molecules on Salmonella montevideo that bind C3 during alternative pathway activation in serum. LPS molecules of Salmonella are composed of lipid A:core oligosaccharide (one copy per molecule), substituted by an O-polysaccharide (O-PS) side chain, which is a linear polymer of 0 to greater than 60 O-antigen repeat units containing mannose. A mutant of S. montevideo called SL5222 that inserts galactose only into core oligosaccharide and mannose only into O-antigen subunits was grown with [3H]mannose and [14C]galactose, so that LPS molecules bearing large numbers of O-antigen subunits have high 3H to 14C ratios, whereas molecules with few O-antigen subunits have lower 3H to 14C ratios. Double-labeled SL5222 was incubated in C8-deficient (C8D) serum or C8D serum with 2 mM Mg++Cl2 and 10 mM ethylene glycoltetraacetic acid (MgEGTA C8D). LPS molecules with covalently attached C3 were identified by binding to anti-C3. LPS molecules that bound C3 under both incubation conditions had O chains seven to eight times longer than the average LPS molecule. SL5222 was then grown in suboptimal concentrations of mannose in order to decrease the number of LPS molecules with long O-PS side chains. C3 attached to progressively shorter chain molecules of LPS as the mannose input was lowered, but still chose the longest available molecules. This finding and recently published observations indicate that C3 can bind to LPS molecules with short O-PS side chains. We postulate that preferential attachment of C3 to long-chain LPS in SL5222 results because long-chain LPS molecules sterically hinder shorter chain LPS molecules from macromolecules. This study provides direct proof that the O-PS of LPS sterically hinders access of large molecules to the outer membrane and indicates that the LPS coat of these bacteria functions as a barrier against large protein molecules.     

Structure of the O-polysaccharide from the lipopolysaccharide of Hafnia alvei strain PCM 1546

An acidic O-polysaccharide isolated by mild acid hydrolysis from the lipopolysaccharide of Hafnia alvei PCM 1546 is composed of D-Gal, D-Glc, D-GlcA, D-GalNAc and O-acetyl groups in the ratios 1:1:1:2:1.6. On the basis of sugar and methylation analyses along with 1D and 2D 1H and 13C NMR spectroscopy, the following structure of the pentasaccharide repeating unit of the polysaccharide was established: [see equation in text].     

Structural analysis of a pectic polysaccharide from the leaves of Diospyros kaki

A pectic polysaccharide DL-2A with a molar mass of 8.5 x 10(5), was obtained from the boiling water extract of Diospyros kaki leaves. It had [alpha]20D -21.8 degrees (c 0.22, H2O) and consisted of rhamnose, arabinose, galactose, xylose and galacturonic acid units in the molar ratio of 0.4:3.4:2.4:1.0:0.8, along with traces of glucuronic acid. About 16.7% of galacturonic acid existed as the methyl ester. A combination of linkage analyses, periodate oxidation, partial acid hydrolysis, selective lithium-degraded reaction, ESIMS, 1H- and 13C- NMR spectral analyses revealed its structural features. It was found that DL-2A possessed an alpha-(1-->4)-galacturonan backbone with some insertions of alpha-1,2-Rhap residues. The side-chains of arabino-3,6-galactan were attached to the backbone via O-4 of Rhap residues and O-3 of GalAp residues, while 4-linked xylose residues (forming short linear chains) were directly linked to O-4 of rhamnose residues, not as part of the xylogalacturonan. These novel structural features enlarge the knowledge on the fine structure of pectic substances in the plant kingdom.     

Complete lipopolysaccharide of Plesiomonas shigelloides O74:H5 (strain CNCTC 144/92). 2. Lipid A, its structural variability, the linkage to the core oligosaccharide, and the biological activity of the lipopolysaccharide

Plesiomonas shigelloides is a Gram-negative bacterium associated with waterborne infections, which is common in tropical and subtropical habitats. Contrary to the unified antigenic classification of P. shigelloides, data concerning the structure and activity of their lipopolysaccharides (LPS and endotoxin) are limited. This study completes the structural investigation of phenol- and water-soluble fractions of P. shigelloides O74 (strain CNCTC 144/92) LPS with the emphasis on lipid A heterogeneity, describing the entire molecule and some of its biological in vitro activities. Structures of the lipid A and the affinity-purified decasaccharide obtained by de-N,O-acylation of P. shigelloides O74 LPS were elucidated by chemical analysis combined with electrospray ionization multiple-stage mass spectrometry (ESI-MS(n)), MALDI-TOF MS, and NMR spectroscopy. Lipid A of P. shigelloides O74 is heterogeneous, and three major forms have been identified. They all were asymmetric, phosphorylated, and hexaacylated, showing different acylation patterns. The beta-GlcpN4P-(1-->6)-alpha-GlcpN1P disaccharide was substituted with the primary fatty acids: (R)-3-hydroxytetradecanoic acid [14:0(3-OH)] at N-2 and N-2' and (R)-3-hydroxydodecanoic acid [12:0(3-OH)] at O-3 and O-3'. The heterogeneity among the three forms (I-III) of P. shigelloides O74 lipid A was attributed to the substitution of the acyl residues at N-2' and O-3' with the secondary acyls: (I) cis-9-hexadecenoic acid (9c-16:1) at N-2' and 12:0 at O-3', (II) 14:0 at N-2' and 12:0 at O-3', and (III) 12:0 at N-2' and 12:0 at O-3'. The pro-inflammatory cytokine-inducing activities of P. shigelloides O74 LPS were similar to those of Escherichia coli O55 LPS.     

Structure of a highly substituted beta-xylan of the gum exudate of the palm Livistona chinensis (Chinese fan)

Structural features of the acidic, highly substituted glycanoxylan (LCP; 87% yield) from the gum exudate of the palm, Livistona chinensis, family Arecaceae, were determined. It had [alpha]D -30 degrees, Mw 1.9x10(5) and a polydispersity ratio Mw/Mn of approximately 1.0. Acid hydrolysis gave rise to Rha, Fuc, Ara, Xyl, and Gal, in a 1:6:46:44:3 molar ratio, and 12% of uronic acid was present. LCP had a highly branched structure with side-chains containing nonreducing end-units (% values are approximate) of Araf (15%), Fucp (4%), Xylp (7%), GlcpA, and 4-Me-GlcpA, and internal 2-O- (5%) and 3-O-substituted Araf (8%), and 2-O-substituted Xylp (14%) units. The (1-->4)-linked beta-Xylp main-chain units of LCP were substituted at O-3 (4%), O-2 (17%), and O-2,3 (16%). Partial acid hydrolysis gave 4-Me-alpha-GlcpA-(1-->2)-[beta-Xylp-(1-->4)](0-2)-Xyl, identified by showing that the uronic acids were single-unit side-chain substituents on O-2. Milder hydrolysis conditions removed from O-3 other side-chains containing Fucp and Araf nonreducing end-units and internal Arap, and 2-O- and 3-O-substituted Araf units. Carboxyl-reduced LCP contained 4-O-methylglucose and glucose in a 3.2:1 molar ratio, arising from GlcpA and 4-OMe-GlcpA nonreducing end-units, respectively. The gum contained small amounts of free alpha-Fucp-(1-->2)-Ara, which corresponds to structures in the polysaccharide. Free myo- and D- or L-chiro-inositol were present in a 9:1 ratio.     

The linkage between O-specific caryan and core region in the lipopolysaccharide of Burkholderia caryophylli is furnished by a primer monosaccharide

From the lipopolysaccharide (LPS) fraction of the plant-pathogenic bacterium Burkholderia caryophylli, the linkage between O-specific caryan and core region was characterised. The LPS fraction was first treated with 48% aqueous HF at 4 degrees C and successively with 1% acetic acid at 100 degrees C. A main oligosaccharide representing the carbohydrate backbone of the core region and a portion of the caryan (three unit of caryose) was isolated by high-performance anion-exchange chromatography. Compositional and methylation analyses, matrix-assisted laser desorption/ionisation mass spectrometry and 2D NMR spectroscopy identified the structure: [carbohydrate structure: see text]. The above residues are alpha-linked pyranose rings, if not stated otherwise. Hep is L-glycero-D-manno-heptose, Car is 4,8-cyclo-3,9-dideoxy-L-erythro-D-ido-nonose and Kdo is 3-deoxy-D-manno-oct-2-ulosonic acid. This finding indicates that QuiNAc residue is the primer monosaccharide, which connects the core oligosaccharide to caryan O-chain.     

Structural determination of the O-antigenic polysaccharide from the Shiga toxin-producing Escherichia coli O171

The structure of the O-antigenic part of the lipopolysaccharide (LPS) obtained from the verotoxin-producing Escherichia coli O171 has been determined. (1)H and (13)C NMR spectroscopy techniques in combination with component analysis were used to elucidate the O-antigen structure of O-deacylated LPS. Subsequent NMR analysis of the native LPS revealed acetylation at O-7/O-9 of the sialic acid residue. The sequence of sugars was determined by inter-residue correlations in (1)H,(1)H-NOESY and (1)H,(13)C-heteronuclear multiple-bond correlation spectra. The O-antigen is composed of pentasaccharide repeating units with one equivalent of O-acetyl groups distributed over two positions: -->4)-alpha-Neu5Ac7,9Ac-(2-->6)-beta-D-Galp-(1-->6)-beta-DGlcp-->(1-->3)-beta-D-Galp-(1-->3)-beta-D-GalpNAc-(1--> Based on biosynthetic considerations, this should also be the biological repeating unit.     

Structural studies of the O-antigenic polysaccharides from the enteroaggregative Escherichia coli strain 87/D2 and international type strains from E. coli O128

The O-antigen of the lipopolysaccharide (LPS) from the enteroaggregative Escherichia coli strain 87/D2 has been determined by component analysis together with NMR spectroscopy. The polysaccharide has pentasaccharide repeating units in which all the residues have the galacto-configuration. The repeating unit of the O-antigen, elucidated using the O-deacylated LPS, is branched with the following structure: Analysis of the 1H NMR spectrum of the LPS revealed O-acetyl groups (approximately 0.7 per repeating unit) distributed over two positions. Subsequent analysis showed that the galactose residue carries acetyl groups at either O-3 or O-4 in a ratio of approximately 2:1. The international reference strain from E. coli O128ab was investigated and the repeating unit of the O-antigens has the following structure: Analysis of the 1H NMR spectrum of the LPS revealed O-acetyl groups (approximately one per repeating unit) distributed over two positions. The integrals of the resonances for the O-acetyl groups indicated similarities between the O-antigen from E. coli O128ab and that of E. coli strain 87/D2, whereas the O-acetyl substitution pattern in the E. coli O128ac O-antigen differed slightly. Enzyme immunoassay using specific anti-E. coli O128ab and anti-E. coli O128ac rabbit sera confirmed the results.     

Structural characterization of the lipid A region of Aeromonas salmonicida subsp. salmonicida lipopolysaccharide

The lipid A components of Aeromonas salmonicida subsp. salmonicida from strains A449, 80204-1 and an in vivo rough isolate were isolated by mild acid hydrolysis of the lipopolysaccharide. Structural studies carried out by a combination of fatty acid, electrospray ionization-mass spectrometry and nuclear magnetic resonance analyses confirmed that the structure of lipid A was conserved among different isolates of A. salmonicida subsp. salmonicida. All analyzed strains contained three major lipid A molecules differing in acylation patterns corresponding to tetra-, penta- and hexaacylated lipid A species and comprising 4'-monophosphorylated beta-2-amino-2-deoxy-d-glucopyranose-(1-->6)-2-amino-2-deoxy-d-glucopyranose disaccharide, where the reducing end 2-amino-2-deoxy-d-glucose was present primarily in the alpha-pyranose form. Electrospray ionization-tandem mass spectrometry fragment pattern analysis, including investigation of the inner-ring fragmentation, allowed the localization of fatty acyl residues on the disaccharide backbone of lipid A. The tetraacylated lipid A structure containing 3-(dodecanoyloxy)tetradecanoic acid at N-2',3-hydroxytetradecanoic acid at N-2 and 3-hydroxytetradecanoic acid at O-3, respectively, was found. The pentaacyl lipid A molecule had a similar fatty acid distribution pattern and, additionally, carried 3-hydroxytetradecanoic acid at O-3'. In the hexaacylated lipid A structure, 3-hydroxytetradecanoic acid at O-3' was esterified with a secondary 9-hexadecenoic acid. Interestingly, lipid A of the in vivo rough isolate contained predominantly tetra- and pentaacylated lipid A species suggesting that the presence of the hexaacyl lipid A was associated with the smooth-form lipopolysaccharide.     

Structural investigation of lipopolysaccharides from nontypeable Haemophilus influenzae: investigation of inner-core phosphoethanolamine addition in NTHi strain 981

LPS of NTHi comprises a conserved tri-l-glycero-D-manno-heptosyl inner-core moiety (l-alpha-D-Hepp-(1-->2)-[PEtn-->6]-l-alpha-D-Hepp-(1-->3)-[beta-D-Glcp-(1-->4)]-l-alpha-D-Hepp-(1-->5)-alpha-Kdop) in which addition of PEtn to the central heptose (HepII) in strain Rd is controlled by the gene lpt6. It was recently shown that NTHi strain 981 contains an additional PEtn linked to O-3 of the terminal heptose of the inner-core moiety (HepIII). In order to establish whether lpt6 is also involved in adding PEtn to HepIII, lpt6 in strain 981 was inactivated. The structure of the LPS of the resulting mutant strain 98llpt6 was investigated by MS and NMR techniques by which it was confirmed that the lpt6 gene product is responsible for addition of PEtn to O-6 of HepII in strain 981. However, it is not responsible for adding PEtn to O-3 of HepIII since the 981lpt6 mutant still had full substitution with PEtn at HepIII.     

Structural features of a pectic arabinogalactan with immunological activity from the leaves of Diospyros kaki

A water-soluble acidic heteroglycan, DL-3Bb, isolated from the leaves of Diospyros kaki, had [alpha](D)(20) -19.9 degrees (c 0.30, water), and contained rhamnose, arabinose, xylose, galactose and galacturonic acid in the molar ratio of 1.0:4.5:0.7:1.5:1.0. About 44% of the galacturonic acid existed as its methyl ester, and O-acetyl groups (approx 5.7%) were also identified. Its molecular weight was determined to be 9.0x10(5) Da by high-performance gel-permeation chromatography. Its structural features were elucidated by a combination of methylation analysis, periodate oxidation, two steps of partial acid hydrolysis, and 1H and 13C NMR spectroscopy and ESI mass spectrometry. The data obtained indicated that DL-3Bb possessed a backbone of a disaccharide of [-->4)-alpha-GalAp-(1-->2)-alpha-Rhap-(1-->], with approx 58.7% substitution at O-4 of the rhamnopyranosyl residues by beta-(1-->4)-linked xylopyranosyl residues, and by beta-(1-->3) and beta-(1-->6)-linked galactopyranosyl (galactan) residues. The side chains were further substituted by arabinofuranosyl residues at O-2 by beta-(1-->4)-linked xylopyranosyl residues and at O-3 by beta-(1-->6)-linked galactopyranosyl residues. Preliminary tests in vitro revealed that it could stimulate LPS-induced B lymphocyte proliferation, but not for ConA-induced T lymphocyte proliferation. It was proposed that the acid-labile arabinofuranosyl residues in the side chains would not be needed for the expression of the enhancement of the immunological activity, and that the presence of GalAp in the backbone has an important, but not crucial effect on the expression of the activity.     

Structural analysis of lipopolysaccharide oligosaccharide epitopes expressed by non-typeable Haemophilus influenzae strain 176

The structure of the lipopolysaccharide (LPS) from non-typeable Haemophilus influenzae strain 176 has been investigated. Electrospray ionization-mass spectrometry (ESIMS) on O-deacylated LPS (LPS-OH) and core oligosaccharide (OS) samples obtained after mild-acid hydrolysis of LPS provided information on the composition and relative abundance of the glycoforms. ESIMS tandem-mass spectrometry on LPS-OH confirmed the presence of minor sialylated and disialylated glycoforms. Oligosaccharide samples were studied in detail using high-field NMR techniques. It was found that the LPS contains the common inner-core element of H. influenzae, L-alpha-D-Hepp-(1-->2)-[PEtn-->6]-L-alpha-D-Hepp-(1-->3)-[beta-D-Glcp-(1-->4)]-L-alpha-D-Hepp-(1-->5)-[PPEtn-->4]-alpha-Kdop-(2-->6)-Lipid A having glycosyl substitution at the O-3 position of the terminal heptose as recently observed for non-typeable H. influenzae strain 486 [M?nsson, M.; Bauer, S. H. J.; Hood, D. W.; Richards, J. C.; Moxon, E. R.; Schweda, E. K. H., Eur. J. Biochem. 2001, 268, 2148--2159]. The following LPS structures were identified as the major glycoforms, the most significant being indicated with an asterisk (*) (glycoforms are partly substituted with Gly at the terminal Hep):     

Characteristics of lipopolysaccharide from Pseudomonas fluorescens (biovar I)]

Lipopolysaccharide (LPS) of the Pseudomonas fluorescens strain IMV 7769 (biovar I) was isolated and investigated. Fractions of the structural parts of the LPS macromolecule, lipid A, the core oligosaccharide, and the O-specific polysaccharide (O-PS), were obtained in a homogeneous state. 2-Hydroxydecanoic, 3-hydroxydecanoic, dodecanoic, 2-hydroxydodecanoic, 3-hydroxydodecanoic, hexadecanoic, octadecanoic, hexadecenoic, and octadecenoic fatty acids were identified in lipid A. In the hydrophilic moiety of lipid A, after acid hydrolysis, several amino acids, phosphoethanolamine, glucosamine, and three unidentified peaks forming a separate cluster together with glucosamine were found. Lipid A was shown to be phosphorylated. Glucose, fucose, rhamnose, glucosamine, galactosamine, two unidentified amino sugars, 2-keto-3-deoxyoctulonic acid (KDO), heptose, ethanolamine, phosphoethanolamine, and alanine were identified in the core oligosaccharide. O-PS of the LPS consisted of repeating trisaccharide fragments that included residues of amino sugars: 4-acetamido-4,6-dideoxy-D-galactose, 2-acetamido-2,6-dideoxy-D-glucose, and 2-acetamido-2,6-dideoxy-L-glucose. During growth, the strain under study excreted exocellular LPS (ELPS) into the medium. The LPS studied was similar to the LPS of the earlier investigated strains P. fluorescens (biovar I) IMV 1152 and IMV 1433 in the structure of O-PS, but differed from them in the composition of both lipid A and the core oligosaccharide. The LPS of the strain studied differed from LPS of the type strain P. fluorescens IMV 4125 (ATCC 13525) in all characteristics determined.