Lipopolysaccharide Isolated from a New O-Antigenic Form (O13) of Vibrio parahaemolyticus

The chemical properties of a lipopolysaccharide (LPS) isolated from a new O-antigenic form (O13) of Vibrio parahaemolyticus were investigated. The LPS contained glucose, galactose, L -glycero-D -manno-heptose and glucosamine. 2-Keto-3-deoxy-octonate (KDO) was not detected in the LPS by the periodate-thiobarbituric acid test (Weissbach's reaction) under conventional hydrolysis conditions. Instead, phosphorylated KDO (X1 and X2) was found in its strong-acid hydrolysate. This sugar composition was identical to that of V. parahaemolyticus O3, O5 and O11 LPS, indicating that, based on the sugar composition, O13 LPS belongs to Chemotype III to which O3, O5 and O11 belong. In addition, structural study demonstrated the presence of KDO 4-phosphate in its inner-core region.     

Chemical Analysis of Lipopolysaccharides of Shigella sonnei Form II Strains Expressed by Cloned Form I Antigen Genes

A compositional sugar analysis was carried out on lipopolysaccharide (LPS) from Shigella sonnei form II in which a plasmid with cloned form I antigen genes had been introduced. The recipient form II strains contained galactose, glucose, heptose, glucosamine, and 2-keto-3-deoxyoctonic acid (KDO) (2: 3: 1: 2: 2) in its LPS, while the transformant form I LPS contained, besides these sugars, N-acetyl-L -altrosaminouronic acid as an additional sugar constituent, which is known to be one of the antigenic determinants of form I antigen.     

Characterization of lipopolysaccharides from four Pasteurella haemolytica serotype strains: evidence for presence of sialic acid in serotypes 1 and 5

Highly purified lipopolysaccharides (LPS) obtained from four strains of Pasteurella haemolytica representative of four different serotypes were studied to ascertain their overall structural elements and sugar and fatty acid compositions. SDS-PAGE analysis revealed that each LPS was of the smooth-type although they differed in migration patterns. Somewhat unusual features of these LPS included the presence of: (a) rhamnose in the core oligosaccharides of serotypes 2 and 3; and (b) sialic acid in the LPS of serotypes 1 and 5. The fatty acids, myristic, hydroxymyristic and palmitic occur in essentially equivalent amounts in each of these LPS. In addition, stearic acid was present in small amounts of serotypes 1 and 5.     

Extraction and Characterization of the Smooth-Type Lipopolysaccharide from Fusobacterium nucleatum JCM 8532 and Its Biological Activities

The lipopolysaccharide (LPS) of Fusobacterium nucleatum JCM 8532 was isolated by hot-phenol water extraction. Most of the LPS was extracted in the phenolic phase and shown to be the smooth-type, whereas the aqueous phase contained mainly rough-type LPS. The chemical composition of the LPS was similar to that reported in other studies, but D -quinovosamine, which may be a major component of O-antigenic polysaccharide, and 3-deoxy-D -manno-2-octulosonic acid (Kdo) were detected for the first time by gas chromatography-mass spectrometry. The biological activities of smooth-type LPS, including limulus activity, lethal toxicity, pyrogenicity, and B lymphocyte mitogenicity, were comparable to those of enterobacterial LPS. Smooth-type LPS inhibited the cell growth and DNA synthesis of adult and fetal human gingival fibroblasts in a dose-dependent manner, suggesting that LPS may play a role in the occurrence of human gingivitis.     

A Comparative Study of the Sugar Composition of O-antigenic Lipopolysaccharides Isolated from Vibrio alginolyticus and Vibrio parahaemolyticus

A comparative study of the sugar composition of O-antigenic lipopolysaccharides (LPS) isolated from Vibrio alginolyticus and those from V. parahaemolyticus was carried out. 3-Deoxy-d-mannooctulosonic acid, 2-keto-3-deoxy octonate (KDO), a regular sugar constituent of gram-negative bacterial LPS, was totally absent from LPS of all V. alginolyticus strains examined as it was from those of V. parahaemolyticus. Furthermore, a KDO-like thiobarbituric acid test-positive substance, identical with that of either V. parahaemolyticus 07 or 012, was also found in LPS from three strains, 505–78, 905–78, and 1013–79 (designated tentatively as group I), out of the five strains of V. alginolyticus tested. LPS from the members of group I contained, as component sugars, glucose, galactose, l-glycero-d-manno-heptose, glucosamine, galactosamine, the KDO-like substance, and an unidentified amino sugar P1. Thus, LPS of the members of group I possessed a similar sugar composition which is similar to that of LPS from either V. parahaemolyticus 07 or 012. LPS of strain 1027–79, one of the other two strains (designated tentatively as gorup II), contained as component sugars, glucose, l-glycero-d-mannoheptose, glucosamine, galactosamine, and the other unidentified amino sugar P2, while LPS of strain 53–79, the other member of group II, contained galactose as an additional component. The results indicate that LPS of strain 1027–79 has a sugar composition similar to that of V. parahaemolyticus 09 LPS.     

Chemical analysis of Azospirillum lipopolysaccharides

Lipopolysaccharides (LPS) were extracted by hot phenol-water from five strains each of Azospirillum lipoferum and Azospirillum brasilense. Rhamnose, glucose, glucosamine and 3-deoxy-d-mannooctulosonic acid were comon sugar constituents of all LPS preparations. 2-O-Mefucose, 3-O-Me-fucose, 3-O-Me-rhamnose and 2-O-Megalactose were found in LPSs of some A. brasilense strains. Fatty acid spectra from all LPSs studied were almost identical with predominance of 3-hydroxymyristic and 3-hydroxypalmitic acids. 3-Hydroxypalmitic acid was the only amide-linked fatty acid. Lipopolysaccharides isolated from A. brasilense showed higher heterogeneity in sugar composition than those from A. lipoferum.Abbreviations glc gas liquid chromatography - ms mass spectrometry - LPS lipopolysaccharide - dOclA 3-deoxy-d-mannooctulosonic acid - 3-OH-16:0 3-hydroxypalmitic acid - nir^- nitrite reductase negative - nir⁺ nitrite reductase positive     

Investigation of Lipopolysaccharides from Sinorhizobium meliloti SKHM1-188 and Two of Its Mutants with Decreased Nodulation Competitiveness

A comparative study of the lipopolysaccharides (LPS) isolated from Sinorhizobium meliloti SKHM1-188 and two of its LPS mutants (Tb29 and Ts22) with sharply decreased nodulation competitiveness was conducted. Polyacrylamide gel electrophoresis with sodium dodecyl sulfate revealed two forms of LPS in all three strains: a higher molecular weight LPS1, containing O-polysaccharide (O-PS), and a lower molecular weight LPS2, without O-PS. However, the LPS1 content in mutants was significantly smaller than in the parent strain. The LPS of the strains studied contained glucose, galactose, mannose, xylose, three nonidentified sugars (X ₁ (TGlc 0.53), X ₂ (TGlc 0.47), and X ₃ (TGlc 0.43)), glucosamine, and ethanolamine, while the LPS of S. meliloti SKHM1-188 additionally contained galactosamine, glucuronic and galacturonic acids, and 2-keto-3-deoxyoctulosonic acid (KDO), as well as such fatty acids as 3-OH C14:0, 3-OH C15:0, 3-OH C16:0, 3-OH C18:0, nonidentified hydroxy X (T_{3-OH C14:0} 1.33), C18:0, and unsaturated C18:1 fatty acids. The LPS of both mutants were similar in the component composition but differed from the LPS of the parent strain by lower X ₂, X ₃, and 3-OH C14:0 contents and higher KDO, C18:0, and hydroxy X contents. The LPS of all the strains were subjected to mild hydrolysis with 1% acetic acid and fractionated on a column with Sephadex G-25. The higher molecular weight fractions (2500–4000 Da) contained a set of sugars typical of intact LPS and, supposedly, corresponded to the LPS polysaccharide portion (PS1). In the lower molecular weight fractions (600–770 Da, PS2), glucose and uronic acids were the major components; galactose, mannose, and X ₁ were present in smaller amounts. The PS1/PS2 ratio for the two mutants was significantly lower than for strain SKHM1-188. The data obtained show that the amount of O-PS–containing molecules (LPS1) in the heterogeneous lipopolysaccharide complex of the mutants was smaller than in the SKHM1-188 LPS; this increases the hydrophobicity of the cell surface of the mutant bacteria, which supposedly contributes to their nonspecific adhesion to the roots of the host plant, thus decreasing their nodulation competitiveness.     

A Chemotaxonomic Study of Vibrio fluvialis Based on the Sugar Composition of the Polysaccharide Portion of the Lipopolysaccharides

A chemotaxonomic study was carried out with a new serotyping scheme comprising 35 O-antigen groups of Vibrio fluvialis on the basis of the sugar composition of the polysaccharide portion of their lipopolysaccharide (LPS). A previously developed rapid method of preparing samples for compositional sugar analysis was employed. The 35 O-antigen groups were divided into 21 chemotypes. It is noted that a rarely occurring component sugar of gram-negative bacterial LPS, D -glycero-D -manno-heptose, and two kinds of uronic acids, i.e., galacturonic acid of a weakly bound type and glucuronic acid of a strongly bound type, were found in common in all the 21 chemotypes. A characteristic sugar component of gram-negative bacterial LPS, 2-keto-3-deoxyoctonate (KDO), was not detectable in any of the 21 chemotypes. Instead, three kinds of “KDO-like substances” were found, one in each of three chemotypes (III, XI and XVII). They were strongly positive in Weissbach's periodate-thiobarbituric acid test for KDO, but definitely not identical to it in high-voltage paper electrophoresis (HVPE); the substance present in chemotype XI was indicated by HVPE to be 3-deoxy-D -threo-hexulosonic acid which is a sugar constituent of Vibrio parahaemolyticus O7 and O12 LPS.     

Roles of Exopolysaccharides and Lipopolysaccharides in the Adsorption of the Siphovirus Phage NM8 to Rhizobium meliloti M11S Cells

The exopolysaccharides produced by Rhizobium meliloti M11S inhibited nonspecifically the adsorption of phage NM8 by coating the cells. But lipopolysaccharides (LPS) had a specific inhibitory effect. Only the polysaccharide moiety of LPS, composed of glucose, glucosamine, galactose, 3-deoxy-D-manno-octulosonic acid (KDO), and large amounts of sialic acid, inhibited phage adsorption; neither the lipid A moiety nor a cellular glucan was involved. Rhizobium strains lacking sialic acids did not bind phage NM8. Inhibition of phage binding by lectin specific for N-acetylneuraminic acid demonstrated that phage NM8 bound to sialic acids. Preincubation of the phage with monosaccharides showed that inactivation of phage was very stereospecific for N-acetylneuraminic acid. Phage adsorption was also strongly inhibited by N-acetylglucosamine, which is not present in the LPS. Therefore, the receptor for phage NM8 appears to be a saccharide site, probably involving the acetyl groups of sialic acids. Received: 8 March 1996 / Accepted: 29 June 1996     

Occurrence of 2-keto-3-deoxyoctonate (KDO) and KDO phosphate in lipopolysaccharides ofBacteriodes species

Occurrence of 2-keto-3-deoxyoctonate (KDO) in lipopolysaccharides (LPS) of genusBacteroides (some strains have recently been reclassified asPorphyromonas orPrevotella) was examined. Strong-acid treatment of LPS isolated fromBacteroides fragilis, Bacteroides (Porphyromonas) gingivalis andBacteroides intermedius, (Prevotella intermedia) released periodate/thiobarbituric acid reaction-positive substances that were not detectable under conventional hydrolysis conditions. These substances were demonstrated to be KDO phosphate by high voltage paper electrophoresis before and after alkaline phosphatase treatment. KDO phosphate was also identified in these LPS by gas-liquid chromatography and gas-liquid chromatography/mass spectrometry. KDO was identified as well in both mild and strong-acid hydrolysates of LPS isolated fromBacteriodes melaninogenicus (Prevotella melaninogenica). Neither KDO nor KDO phosphate was detectable in LPS ofBacteriodes asaccharolyticus (Porphyromonas asaccharolytica) even after the strong-acid treatment of LPS. These findings indicate that there are possible structural variations in the inner core region ofBacteroides LPS.     

Immunochemical investigations of antigens isolated fromBacteroides ovatus strain ATCC 8483

A saline extract (SE) and a phenol/water extract (WL) were prepared fromBacteroides ovatus strain ATCC 8483. A fraction CS was isolated from the culture supernatant. WL was further split by ultracentrifugation into lipopolysaccharide (LPS) and supernatant (L₁). Fractions SE, WL, LPS and L₁ reacted serologically with homologous antiserum but did not cross-react with antisera against heterologousBacteroides serotypes. Fraction CS was inactive in haemagglutination, haemagglutination inhibition and immunoelectrophoresis tests. SE, WL, LPS and L₁ proved to be serologically heterogeneous. A distinct serological specificity for SE was demonstrated. The serological reactivity in SE and WL was not altered after treatment with proteolytic enzymes yet completely destroyed in WL and partially in SE by sodium metaperiodate. SE, WL, LPS and L₁ contained the sugar components rhamnose, fucose, ribose, mannose, galactose, glucose and glucosamine in different molar ratios for each fraction. Galactosamine was found in WL and LPS, uronic acid in WL and L₁. Two unidentified aminohexoses were detected in WL, one of which was also detectable in L₁ and SE. 2-Keto-3-deoxyaldonic acid was demonstrated in LPS and L₁ after strong acid hydrolysis.     

Occurrence of Uronic Acid in Lipopolysaccharides of Vibrionaceae

The occurrence of uronic acid as a sugar constituent of lipopolysaccharides (LPS) in Vibrionaceae was demonstrated for the first time. More than 100 strains were examined. Of five genera constituting Vibrionaceae, i.e., Vibrio, Aeromonas, Plesiomonas, Photobacterium, and Lucibacterium, the latter three contained uronic acid in LPS of all of their constituting members examined, while it was totally lacking in Aeromonas LPS so far tested. Only the members of genus Vibrio were found to be divided into uronic acid-containing and -lacking groups; V. parahaemolyticus, V. alginolyticus, V. fisheri, V. costicola, Beneckea (‘Vibrio’), and V. fluvialis belonged to the former, while all four biotypes of V. cholerae regardless of their serotypes, V. vulnificus and V. anguillarum, belonged to the latter group. The uronic acid content of V. parahaemolyticus O1 to O12 LPS ranged from 1.6 to 4.2%. The uronic acid residue released from V. parahaemolyticus O1, O4, O10, and O12 LPS by heating in 5% acetic acid at 100 C for 2 hr was identified as galacturonic acid; in particular, that from 012 LPS was characterized as d-galacturonic acid.     

Isolation and Characterization of Antitumor Lipopolysaccharide from Proteus mirabilis

Systematic isolation of the cell constituents of Proteus mirabilis RMS–203 was performed to find out localization of antitumor principle only in the lipopolysaccharide (LPS) layer of the cell wall fraction.

LPS with strong antitumor activity was extracted from P. mirabilis RMS–203 by phenol-water method followed by purification on DEAE-Sephadex A–50 column chromatography.

The main components of purified LPS were galactose, hexosamine, 2-keto-deoxy-octonic acid (KDO), myristic acid, β-hydroxymyristic acid and α,ε-diaminopimelic acid.

The minimal effective dose of LPS against Ehrlich solid carcinoma in mice was 0.1~1.0 μg/mouse. LD₅₀ in mice and pyrogenicity in rabbits were 28 mg/kg and 10^?3–10^?5 μg/rabbit, respectively.     

Biological activity of (Lipo)polysaccharides of the exopolysaccharide-deficient mutant Rt120 derived from <Emphasis Type="Italic">Rhizobium leguminosarum</Emphasis> bv. trifolii strain TA1

Lipopolysaccharides (LPS) from Rhizobium leguminosarum biovar trifolii TA1 (RtTA1) and its mutant Rt120 in the pssB-pssA intergenic region as well as degraded polysaccharides (DPS) derived from the LPS were elucidated in terms of their chemical composition and biological activities. The polysaccharide portions were examined by methylation analysis, MALDI-TOF mass spectrometry, and ¹H NMR spectroscopy. A high molecular mass carbohydrate fraction obtained from Rt120 DPS by Sephadex G-50 gel chromatography was composed mainly of L-rhamnose, 6-deoxy-L-talose, D-galactose, and D-galacturonic acid, whereas that from RtTA1 DPS contained L-fucose, 2-acetamido-2,6-dideoxy-D-glucose, D-galacturonic acid, 3-deoxy-3-methylaminofucose, D-glucose, D-glucuronic acid, and heptose. Relative intensities of the major ¹H NMR signals for O-acetyl and N-acetyl groups were 1: 0.8 and 1: 1.24 in DPS of Rt120 and RtTA1, respectively. The intact mutant LPS exhibited a twice higher lethal toxicity than the wild type LPS. A higher in vivo production of TNFα and IL-6 after induction of mice with Rt120 LPS correlated with the toxicity, although the mutant LPS induced the secretion of IL-1β and IFNγ more weakly than RtTA1 LPS. A polysaccharide obtained by gel chromatography on Bio-Gel P-4 of the high molecular mass material from Rt120 had a toxic effect on tumor HeLa cells but was inactive against the normal human skin fibroblast cell line. The polysaccharide from RtTA1 was inactive against either cell line. The potent inhibitory effect of the mutant DPS on tumor HeLa cells seems to be related with the differences in sugar composition.     

Chemical and Biological Properties of Lipopolysaccharide from a Marine Bacterium,Photobacterium phosphoreum PJ-1

The chemical and biological properties of the lipopolysaccharide (LPS) isolated from a marine bacterium, Photobacterium phosphoreum PJ-1, were studied. This LPS consists of 40.6% carbohydrate, 27.3% fatty acid, 0.2% 2-keto-3-deoxyoctonate (KDO) and other components. One characteristic of this LPS is its small amount of KDO, the basic component of the usual LPS. Electrophoresis in sodium dodecylsulfate polyacrylamide gel revealed at least two staining bands for carbohydrates. These bands were continuous and broad, and showed rapid electrophoretic mobility which corresponded closely to the fastest moving band of LPS from Salmonella typhimurium. This LPS preparation had adjuvant activity, lethality for ddY mice, and the ability to gel Limulus amebocyte lysate, and the strength of these activities corresponded closely to those of LPS preparations from Escherichia coli 0111:B4 and S. typhimurium. In the test for lethality of the LPS for ddY mice, the lethal action appeared in two phases depending on the dose used for intravenous (i.v.) injection : the early lethal action appeared within 30 min after injection of 250 μg or less, and the late lethal action occurred gradually after 16 hr at doses of 500 μg or more. The total (both phases) LD50 of this LPS (i.v.) for ddY mice was 265 μg per mouse and in only the late phase it was 500 μg. These results show that in spite of structual differences in regard to KDO content, LPS from P. phosphoreum PJ-1 has some biological properties similar to those of LPS from E. coli 0111:B4 and S. typhimurium but it shows no immunological cross-reaction with other LPS.     

Sialic Acid-Containing Lipopolysaccharides of Salmonella O48 Strains—Potential Role in Camouflage and Susceptibility to the Bactericidal Effect of Normal Human Serum

Sialic acid (N-acetylneuraminic acid, NeuAc) plays an essential role in protecting gram-negative bacteria against the bactericidal activity of serum and may contribute to the pathogenicity of bacteria by mimicking epitopes that resemble host tissue components (molecular mimicry). The role of sialic acid (NeuAc)-containing lipopolysaccharides (LPS) of Salmonella O48 strains in the complement activation of normal human serum (NHS) was investigated. NeuAc-containing lipooligosaccharides cause a downregulation of complement activation and may serve to camouflage the bacterial surface from the immunological response of the host. Serotype O48 Salmonella strains have the O-antigen structure containing NeuAc while its serovars differ in outer membrane protein composition. In this study, the mechanisms of complement activation responsible for killing Salmonella O48 serum-sensitive rods by NHS were established. Four of such mechanisms involving pathways, which are important in the bactericidal mechanism of complement activation, were distinguished: only the classical/lectin pathways, independent activation of the classical/lectin or alternative pathway, parallel activation of the classical/lectin and alternative pathways, and only the alternative pathway important in the bactericidal action of human serum. To further study the role of NeuAc, its content in bacterial cells was determined by gas-liquid chromatography-mass spectrometry in relation to 3-deoxy-D-manno-2-octulosonic acid (Kdo), an inherent constituent of LPS. The results indicate that neither the presence of sialic acid in LPS nor the length of the O-specific part of LPS containing NeuAc plays a decisive role in determining bacterial resistance to the bactericidal activity of complement and that the presence of sialic acid in the structure of LPS is not sufficient to block the activation of the alternative pathway of complement. We observed that for three strains with a very high NeuAc/Kdo ratio the alternative pathways were decisive in the bactericidal action of human serum. The results indicated that those strains are not capable of inhibiting the alternative pathway very effectively. As the pathogenicity of most Salmonella serotypes remains undefined, research into the interactions between these bacterial cells and host organisms is indispensable.     

Serological Specificity of the Lipopolysaccharides, the Major Antigens of Pseudomonas syringae

The nature of major antigens of Pseudomonas syringae was studied on one strain of four pathovars (pvs aptata, mors-prunorum, phaseolicola and tabaci) belonging to four separate serogroups. Bacterial antigens were prepared by 4 procedures: extraction by phenol-water (PW), by citrate-NaCl (CN), by trichloracetic acid (TCA), and precipitation of a glycoproteic extracellular complex (GP). 3-Deoxy-2-octulosonic acid (KDO) revelation in all the extracts showed that the four procedures led to antigens containing similar amounts of lipopolysaccharide (LPS). Twenty polyclonal antisera were raised in rabbits against whole bacteria and the different extracts. Serological reactions were tested by gel double diffusion (DD) and indirect immunofluorescent staining (IF). The anti-whole cell sera were shown to contain mostly anti-LPS antibodies. For each pathovar, whole bacteria used as antigens in DD gave precipitation bands identical to the bands given by the LPS extracts (PW, CN or TCA), identical to the heated bacteria (HB), and identical to LPS sidechain preparations. The GP extract itself was shown to be rich in LPS. To serotype P. syringae, it is advised to raise antisera against either whole bacteria or GP extracts; whereas the reacting antigens for DD would be heated bacteria.     

Chemical composition of lipopolysaccharides from Legionella bozemanii and Legionella longbeachae

Lipopolysaccharides (LPS) from Legionella bozemanii serogroup 1 and Legionella longbeachae serogroup 1 were subjected to chemical analyses. The lipid A part of both LPSs contained 2,3-dideoxy-2,3-diamino-d-glucose as major constituents and d-glucosamine and glycerol as minor constituents of the sugar backbone structure. Both LPSs exhibited a very complex fatty acid composition. Twenty amide-linked 3-hydroxy fatty acids were detected in LPS of L. longbeachae, whereas seventeen were encountered in LPS of L. bozemanii. Both LPSs contained nine ester-linked nonhydroxy fatty acids and the unique long-chain fatty acids 27-oxo-octacosanoic acid, 29-oxotriacontanoic acid, heptacosane-1,27-dioic acid and nonacosane-1,29-dioic acid. SDS-PAGE showed that L. bozemanii produced smooth-form LPS, whereas L. longbeachae LPS was mainly of the R-type. Composition analyses were in accordance with these electrophoretic patterns. d-Quinovosamine and l-fucosamine constituted 80 mol% of the polysaccharide part of L. bozemanii LPS. Other sugars identified were d-glucosamine, d-mannose, d-glucose, l-rhamnose, d-glycero-d-manno-heptose, l-glycero-d-mannoheptose, 2-keto-3-deoxy-octonic acid and glycerol. The polysaccharide chain from LPS of L. longbeachae appeared to be shorter, but composed of the same sugars except l-fucosamine. Both LPSs contained glycerol phosphate and glucosamine phosphate and L. longbeachae LPS contained in addition glucose phosphate.Abbreviations EI Electron impact - GlcN3N 2,3-Diamino-2,3-dideoxy-d-glucose - HPAEC High pH anion-exchange chromatography - Kdo 2-Keto-3-deoxy-octonic acid - LPS Lipopolysaccharide - PCP Phenol/chloroform/petroleum ether solvent - PED Pulsed electrochemical detection - PS Polysaccharide - TFA Trifluoroacetyl - TMS Trimethylsilyl     

Peculiarities of the structure of thePseudomonas fluorescens IMV 247 (Biovar II) lipopolysaccharide

The results of the study of thePseudomonas fluorescens IMV 247 (biovar II) lipopolysaccharide (LPS) isolated from the dry bacterial mass by Westphal’s method and purified by repeated ultracentrifugation are presented. The macromolecular organization of the LPS is characterized by the presence of S and R forms of LPS molecules in a 1 : 1 ratio. The structural components of the LPS molecule-lipid A, the core oligosaccharide, and the 0-specific polysaccharide-were isolated and characterized. 3-Hydroxydecanoic, 2-hydroxydodecanoic, 3-hydroxydodecanoic, and dodecanoic acids proved to be the main lipid A fatty acids. Glucosamine, phosphoethanolamine, and phosphorus were identified as the components of the lipid A hydrophilic portion. Glucose, galactose, arabinose, rhamnose, glucosamine, galactosamine alanine, phosphoethanolamine, phosphorus, and 2-keto-3-deoxyoctulonate (KDO) were revealed in the heterogeneous fraction of the core oligosaccharide. The 0-specific polysaccharide chain was composed of repeating tetrasaccharide units consisting of L-rhamnose (L-Rha), 3,6-dideoxy-3-[(S)-3-hydroxybutyramido]-D-glucose (D-Qui3NHb), 2-acetamido-2,4,6-trideoxy4 [(S)-3-hydroxybutyramido]-D-glucose (D-QuiNAc4NHb), and 2-acetamido-2-deoxy-D-galacturonic acid (D-GalNAcA) residues. A peculiarity of the 0-specific polysaccharide was that it released, upon partial acid hydrolysis, the nonreducing disaccharide GalNAcA→ QuiNAc4NHb with a 3-hydroxybutyryl group glycosylated intramolecularly with a QuiN4N residue. Double immunodiffusion in agar and lipopolysaccharide precipitation reactions revealed no serological interrelationship between the strain studied and theP. fluorescens strains studied earlier.