Campylobacter Jejuni Serotypes Research Articles

Biomolecule sulphation and novel methylations related to Guillain-Barré syndrome-associated Campylobacter jejuni serotype HS:19.

Campylobacter jejuni strains that produce sialylated lipooligosaccharides (LOS) can cause the immune-mediated disease Guillain-Barré syndrome (GBS). The risk of GBS after infection with C. jejuni Penner serotype HS:19 is estimated to be at least six times higher than the average risk. Aside from LOS biosynthesis genes, genomic characteristics that promote an increased risk for GBS following C. jejuni HS:19 infection, remain uncharacterized. We hypothesized that strains with the HS:19 serotype have unique genomic features that explain the increased risk for GBS. We performed genome sequencing, alignments, single nucleotide polymorphisms' analysis and methylome characterization on a subset, and pan-genome analysis on a large number of genomes to compare HS:19 with non-HS:19 C. jejuni genome sequences. Comparison of 36 C. jejuni HS:19 with 874 C. jejuni non-HS:19 genome sequences led to the identification of three single genes and ten clusters containing contiguous genes that were significantly associated with C. jejuni HS:19. One gene cluster of seven genes, localized downstream of the capsular biosynthesis locus, was related to sulphation of biomolecules. This cluster also encoded the campylobacter sialyl transferase Cst-I. Interestingly, sulphated bacterial biomolecules such as polysaccharides can promote immune responses and, therefore, (in the presence of sialic acid) may play a role in the development of GBS. Additional gene clusters included those involved in persistence-mediated pathogenicity and gene clusters involved in restriction-modification systems. Furthermore, characterization of methylomes of two HS:19 strains exhibited novel methylation patterns (5′-CATG-3 and 5′-m6AGTNNNNNNRTTG-3) that could differentially effect gene-expression patterns of C. jejuni HS:19 strains. Our study provides novel insight into specific genetic features and possible virulence factors of C. jejuni associated with the HS:19 serotype that may explain the increased risk of GBS.

Synthesis of the 2'-Azidoethyl Trisaccharide, 6d-altroHepp-GlcNAc-Gal Hapten, an O-Antigenic Repeating Unit of Campylobacter jejuni Serotypes O:23 and O:36

A trisaccharide, 6d-Altro-Hepp<TEX>$\alpha$</TEX> (1<TEX>$\rightarrow$</TEX>3) GlcNAc<TEX>$\beta$</TEX> (1<TEX>$\rightarrow$</TEX>3) Gal<TEX>$\alpha$</TEX> (1<TEX>$\rightarrow$</TEX><TEX>$OCH_2CH_2N_3$</TEX>, as an O-antigenic repeating unit of Campylobacter jejuni serotypes O:23 and O:36, was synthesized. Coupling of the 6d-altro-Hepp<TEX>$\alpha$</TEX> (1<TEX>$\rightarrow$</TEX>3) GlcNAc<TEX>$\beta$</TEX> (1<TEX>$\rightarrow$</TEX>SEt donor with Gal<TEX>$\alpha$</TEX> (1<TEX>${\rightarrow}OCH_2CH_2Cl$</TEX> acceptor in the presence of NIS-TfOH promoter afforded the trisaccharide having the <TEX>$\beta$</TEX> (1<TEX>$\rightarrow$</TEX>3) Gal linkage. <TEX>$\beta$</TEX> -Stereospecificity and the desired regioselectivity for the 3-OH Gal are obtained. Subsequent hydrogenation, acetylation, azide displacement, hydrazinolysis, Nacetylation, and finally deacetylation furnished the title trisaccharide hapten for further glycoconjugation.

Strain and host characteristics of Campylobacter jejuni infections in Finland

The relative importance of different risk-factors for Campylobacter infections and the role of bacterial strain and host characteristics are uncertain. Swimming in natural sources of water was recently described as a novel independent risk-factor for domestically-acquired Campylobacter infections. The present study investigated exposure factors and demographical characteristics (collected in a questionnaire), and determined whether Campylobacter jejuni serotypes could be linked to each other or to the severity of the disease in domestically-acquired sporadic C. jejuni infections during a seasonal peak in Finland. Swimming was associated positively with an age of <or= 5 years, and C. jejuni serotype Pen 6,7 was found significantly more frequently among patients who reported swimming. The geographical distribution among serotypes differed, in that 54% of the isolates belonging to the Pen 4 complex serotype were identified in the Helsinki area, and 74% of the Pen 21 isolates were from the Kuopio area. Pen 57 was associated with a disease of shorter duration, but no serotype could be linked to hospitalisation or antimicrobial therapy. However, advanced age was associated with hospitalisation and a longer period of hospitalisation. Risk-factors and sources of infection for C. jejuni infection may not be identical for all individuals. This study supports the concept that individuals belonging to different age groups and living in different geographical areas may acquire C. jejuni infections from different sources.

Antibodies to ganglioside GM1 and Campylobacter jejuni in patients with Guillain-Barre syndrome

Guillain-Barré syndrome (GBS) is an acute immune mediated neuropathy, polyradiculoneuritis, characterized by rapid onset of symmetric extremity muscle paralysis, areflexia and albuminocytological dissociation in the cerebrospinal fluid (CSF). Recently, the heterogeneity of GBS has been noticed with definition of several GBS variants. The axonal GBS associated with anti-GM1 antibodies is the most important variant with the specific role of Campylobacterjejuni (CJ) in the induction of the disease. The role of our study was to determine the frequency of antecedent infection with CJ in the population of our patients with GBS, the association with anti-GM1 antibodies and the distribution of these antibodies within clinical forms of the disease. The diagnosis of GBS has been established in 17 patients according to clinical, electrophysiological and laboratory (CSF) criteria. The serum antibodies to 63 kDa flagellar protein isolated from CJ serotype 0:19 were determined by ELISA and Western blot and serum anti-GM1 antibodies by ELISA. In relation to the disability score two patients were ambulatory, five were ambulatory with support, seven were bedridden and two patients needed respirator. Five (29%) patients had pure motor, while 12 (71%) had sensorimotor GBS. The cranial nerves were involved in 11 (65%) and 9 (53%) patients had autonomic dysfunction. Electromyoneurography showed primary axonal, predominantly motor neuropathy in 6 (35%) and demyelinating sensorimotor neuropathy in 11 (65%) patients. The CSF protein content ranged from 0.47 to 3.88 g/L. The antecedent infection with CJ was shown by serum antibodies to CJ flagellar protein in 12 (71%) patients. Fifteen (88%) patients had IgG anti-GM1 antibodies. Twelve (71%) patients had both antibodies. In relation to the clinical form, anti-CJ antibodies were found in 8 (73%) out of 11 patients with demyelinating GBS and in 4 (66.6%) out of 6 patients with axonal GBS. The high titer of anti-GM1 antibodies was found in all patients (100%) with axonal and in 9 (82%) out of 11 patients with demyelinating GBS. The association of IgG anti-CJ and IgG anti-GM1 antibodies was found in 4 (66.6%) out of 6 patients with axonal and in 8 (73%) out of 11 patients with demyelinating GBS. The main features of our patients with GBS were high frequency of antecedent infection with CJ, unusually frequent association with anti-GM1 antibodies, and equally frequent association of anti-CJ and anti-GM1 antibodies in both, axonal and demyelinating GBS.

Molecular population genetic analysis of Campylobacter jejuni HS:19 associated with Guillain-Barré syndrome and gastroenteritis.

Infection with Campylobacter jejuni serotype HS:19 is associated with the development of Guillain-Barré syndrome (GBS). To determine whether a particular HS:19 clone is associated with GBS, multilocus enzyme electrophoresis (MLEE) was used to analyze a worldwide collection of isolates. There were 34 electropherotypes (ETs) in 3 phylogenetic clusters among 83 C. jejuni isolates. Cluster I contained all HS:19 strains, and a single ET (ET4) accounted for most HS:19 strains. HS:19 strains did not occur in any of the other clusters. ET4 contained isolates from different geographic locations, indicating global spread of this clone. Furthermore, ET4 contained isolates from patients with uncomplicated enteritis and GBS, as well as isolates from animal sources. The results of this study show that HS:19 strains comprise a clonal, although not monomorphic, population, which is distinct from non-HS:19 strains within C. jejuni. A unique clone associated with GBS was not identified by use of MLEE.

GROWTH OF CAMPYLOBACTER JEJUNI IN VARIOUS MEDIA UNDER DIFFERENT ATMOSPHERIC CONDITIONS

Abstract The growth characteristics of several Campylobacter jejuni serotypes were examined using a variety of media and atmospheric conditions. The strains grew well in a variety of liquid media using a standard CO2 incubator in an atmosphere of 5% CO2 and moist air at 40C. When growth media were supplemented with a mixture of antibiotics for selectivity, it was found that the best growth was achieved in Hunt broth, and that the presence of blood enabled the strains to overcome the toxic effects of the antibiotics.

Water-borne Campylobacter jejuni infection in a Danish town—a 6-week continuous source outbreak

OBJECTIVE: To determine the cause and characteristics of illness of a Campylobacter jejuni outbreak in Denmark in 1995--96. METHODS: A retrospective follow-up study was designed for culture-confirmed cases and for residents without a bacteriologic diagnosis. Stored clinical and environmental isolates were analyzed by serotyping and genotyping with restriction endonuclease analysis (REA), pulsed-field gel electrophoresis (PFGE) and ribotyping. RESULTS: Campylobacter jejuni was isolated from 110 residents and visitors to the area. However, an estimate based on a telephone survey indicated that some 2400 people were affected by the outbreak. Water samples obtained from the community waterworks contained Campylobacter jejuni serotype O2, the same serotype as in all but one of the 30 stored isolates from the outbreak. The water and clinical isolates also showed the same DNA profile, except for the single strain showing the distinct serotype. The contamination of the water supply was traced back to contamination of ground water due to a break in a sewage pipe. CONCLUSIONS: A retrospective and demographic epidemiologic investigation of both culture-confirmed and non-culture-confirmed cases in the town combined with typing of the isolates was crucial in defining the extent and cause of the outbreak.

A campylobacter outbreak associated with stir-fried food.

An outbreak of gastrointestinal illness affecting 12 of 29 customers of a 'Hawaiian' theme restaurant specializing in stir-fried food occurred in Cardiff, Wales in February 1997. Campylobacter jejuni serotype HS50 phage type 49 (PT49) was isolated from 5 cases. A total of 47 isolates of C. jejuni HS50 PT49 were identified from Wales during 1997, of which 11 were isolated in late February or early March and from the Cardiff area. In the outbreak, illness was associated with eating stir-fried chicken pieces (relative risk 4.81, 95% confidence interval (CI) 0.76-30.44, P=0.03) and a dose-response relationship between risk of illness and amount of chicken consumed was observed (chi2-test for linear trend 3.96, P=0.047). Undercooking of chicken was probably due to a combination of inadequate cooking time and use of large chicken pieces. This is the first time that stir-fried food has been associated with a campylobacter outbreak. The incident also illustrates the value of routine campylobacter subtyping in supporting outbreak investigation.

Lipo-oligosaccharides of Campylobacter jejuni serotype O:10. Structures of core oligosaccharide regions from a bacterial isolate from a patient with the Miller-Fisher syndrome and from the serotype reference strain

Lipo-oligosaccharide ( LOSa) was obtained by phenol-water extraction of bacterial cells of an isolate PG 836, identified as Campylobacter jejuni serotype O:10, from a patient who subsequently developed the Miller-Fisher syndrome (MFS). The product was separated into a water-insoluble gel of low M r and a water-soluble component of high M r. The structure of the core oligosaccharide region in LOSa is reported herein for comparison with LOSb from the C. jejuni O:10 reference strain, and is based on investigations carried out on: (1) O-deacylated LOSa; (2) the core oligosaccharide ( OS 1a) liberated on acetic acid hydrolysis of the ketosidic linkages to lipid A, with accompanying loss of N-acetylneuraminic acid residues; (3) the product of the removal of phosphate residues from OS 1a to give OS 2a; and (4) the Smith degradation of OS 2a to yield a mixture of Os 3a and OS 4a. The results revealed that the core oligosaccharide region in LOSa from the MFS bacterial isolate had chains ( 1a), of which some were terminated by an N-acetylneuraminobiose [Neu5Ac(α2–8)Neu5Ac] unit in a GD 3 [Neu5Ac-Neu5Ac-Gal] epitope, and the inner regions of which were different from those of other C. jejuni serotypes. Similar experiments on LOSb from bacterial cells of the C. jejuni O:10 reference strain showed that the core oligosaccharide unit [ 1a, R = P (phosphoric monoester)] of LOSa from the MFS isolate was more uniformly complete than that of the O:10 reference strain [ 1b, R = AEP (2-aminoethylphosphate)] differing in the nature of the phosphate substituent at the inner heptose residue. The close structural relationship of LOSa from the MFS associated bacterium to LOSb from the O:10 reference strain runs parallel to that of the previously studied Guillain-Barré syndrome (GBS) associated bacterium typed as C. jejuni O:19 in comparison with the lipo-oligosaccharide from the reference strain. Preliminary studies on the high M r components showed that those from the O:10 strains were indistinguishable from each other, but were structurally unrelated to those from the GBS associated C. jejuni serotype O:19 isolates and the O:19 reference strain [G.O. Aspinall, A.G. McDonald, and H. Pang, Biochemistry, 33 (1994) 250–255].

Restriction fragment length polymorphism analysis and random amplified polymorphic DNA analysis of Campylobacter jejuni strains isolated from patients with Guillain-Barré syndrome.

Campylobacter jejuni serotype O19 strains associated with the Guillain-Barré syndrome (GBS) and other strains were examined by restriction fragment length polymorphism (RFLP) analysis of polymerase chain reaction products of the flaA genes and by random amplified polymorphic DNA (RAPD) analysis. RFLP analysis showed that regardless of LIO serotype, geographic origins, or association with GBS, the O19 isolates shared an identical digestion pattern by each of four restriction endonucleases, DdeI, MboI, MseI, and AluI. In contrast, among C. jejuni O1 or O2 strains, RFLP patterns were different even among strains of the same LIO serotype. The results of the RAPD analysis were consistent with the flaA RFLP data. These data indicate that all of the O19 strains that were tested were closely related to one another whether they were or were not associated with GBS.

Molecular mimicry of host structures by bacterial lipopolysaccharides and its contribution to disease

The core oligosaccharides of low-molecular-weight lipopolysaccharide (LPS), also termed lipooligosaccharide (LOS), of pathogenic Neisseria spp. mimic the carbohydrate moieties of glycosphingolipids present on human cells. Such mimicry may serve to camouflage the bacterial surface from the host. The LOS component is antigenically and/or chemically identical to lactoneoseries glycosphingolipids and can become sialylated in Neisseria gonorrhoeae when the bacterium is grown in the presence of cytidine 5′-monophospho- N-acetylneuraminic acid, the nucleotide sugar of sialic acid. Strains of Neisseria meningitidis and Haemophilus influenzae also express similarly sialylated LPS. Sialylation of the LOS influences susceptibility to bactericidal antibody, may decrease or prevent phagocytosis, cause down-regulation of complement activation, and decrease adherence to neutrophils and the subsequent oxidative burst response. The core oligosaccharides of LPS of Campylobacter jejuni serotypes which are associated with the development of the neurological disorder, Guillain-Barré syndrome (GBS), exhibit mimicry of gangliosides. Cross-reactive antibodies between C. jejuni LPS and gangliosides are considered to play an important role in GBS pathogenesis. In contrast, the O-chain of a number of Helicobacter pylori strains exhibit mimicry of Lewis x and Lewis y blood group antigens. The role of this mimicry remains to be investigated, but may play a role in bacterial camouflage, the induction of autoimmunity and immune suppression in H. pylori-associated disease.

Molecular mimicry of host structures by bacterial lipopolysaccharides and its contribution to disease.

The core oligosaccharides of low-molecular-weight lipopolysaccharide (LPS), also termed lipooligosaccharide (LOS), of pathogenic Neisseria spp. mimic the carbohydrate moieties of glycosphingolipids present on human cells. Such mimicry may serve to camouflage the bacterial surface from the host. The LOS component is antigenically and/or chemically identical to lactoneoseries glycosphingolipids and can become sialylated in Neisseria gonorrhoeae when the bacterium is grown in the presence of cytidine 5'-monophospho-N-acetylneuraminic acid, the nucleotide sugar of sialic acid. Strains of Neisseria meningitidis and Haemophilus influenzae also express similarly sialylated LPS. Sialylation of the LOS influences susceptibility to bactericidal antibody, may decrease or prevent phagocytosis, cause down-regulation of complement activation, and decrease adherence to neutrophils and the subsequent oxidative burst response. The core oligosaccharides of LPS of Campylobacter jejuni serotypes which are associated with the development of the neurological disorder, Guillain-Barré syndrome (GBS), exhibit mimicry of gangliosides. Cross-reactive antibodies between C. jejuni LPS and gangliosides are considered to play an important role in GBS pathogenesis. In contrast, the O-chain of a number of Helicobacter pylori strains exhibit mimicry of Lewis(x) and Lewis(y) blood group antigens. The role of this mimicry remains to be investigated, but may play a role in bacterial camouflage, the induction of autoimmunity and immune suppression in H. pylori-associated disease.

Induction of antibodies reactive with GM2 ganglioside after immunization with lipopolysaccharides from Camplyobacter jejuni.

Ganglioside GM2, expressed on the surface of some human cancers, is a promising target for immune therapy, since GM2 antibodies are cytotoxic, can be induced in humans by vaccination, and the presence of GM2 antibodies is associated with a better prognosis in melanoma patients. In our efforts to induce long-lived, cytotoxic GM2 antibodies, we investigated lipopolysaccharides (LPS) containing "GM2-like" oligosaccharides. LPS were prepared from Campylobacter jejuni serotypes O:1, O:23, or O:36 (all sharing the oligosaccharide structure GalNAcbeta1-4Gal(113NeuAc)-Hex with ganglioside GM2), and tested for their ability to induce GM2-reactive antibodies. Immunization of NZW rabbits (2 animals per vaccine) with LPS from C. jejuni serotype O:1 in Freund's adjuvant resulted in production of high-titer IgG antibodies reactive with purified bovine brain GM2 in ELISA, dot-blot immune strains and immune thin-layer chromatography, and with GM2 derived from various human tumors by immune thin-layer chromatography. These rabbit antibodies bound to cancer cell lines expressing GM2 on their cell surface, as determined by mixed hemadsorption assays, mediating strong antibody-dependent cellular cytotoxicity (ADCC) with tumor cells expressing cell-surface GM2. Antibodies induced by vaccination with C. jejuni serotype O:1 were higher-titer (IgG ELISA titer > 1:60,000) than antibodies induced by immunization with purified GM2 (IgG ELISA titer > 1:200). Immunization with LPS from C. jejuni serotype O:36 resulted in production of moderately high-titer IgM and low-titer IgG GM2 antibodies. Immunization with LPS from C. jejuni serotype O:23 did not elicit GM2-reactive antibodies. No clinical symptoms were observed in animals immunized with these LPS preparations, with purified GM2 ganglioside, or with LPS derived from C. jejuni serotype O:19 (containing a GM1-like oligosaccharide). Our results indicate that lipopolysaccharides sharing carbohydrate epitopes with gangliosides may be useful immunogens for inducing antibodies to ganglioside antigens.

Flagellin gene profiling of Campylobacter jejuni heat-stable serotype 1 and 4 complex

Flagellin gene ( flaA) sequence polymorphisms were used to discriminate amongst 167 strains of Campylobacter jejuni serotype HS1 and the HS4 complex. Direct PCR of cell suspensions provided a rapid method for analysing DNase-negative strains, whereas purified DNA was necessary for the DNase-positive strains. Nine different PCR-RFLP patterns (genotypes) were identified by analysis with HinΛ and 12 with Ddel, giving a total of 19 combined flaA profile types. The most common combined fla types were H1D1 (35%) and H1D2 (20%) for serotype HS1, and H1D2 (23%) and H4D7 (43%) for serotype HS4. Comparison of flaA typing with other key subtyping methods for C. jejuni showed it to be less discriminatory than pulsed field gel electrophoretic (PFGE) profiling, but more so than ribotyping. Fla types provided a useful indication of strain diversity, but as some were conserved across different serotypes, ribotypes and PFGE types, the same fla type could not be used as the sole basis for grouping strains. We provide evidence for several distinct subgroups based on conserved multiple genomic criteria within the HS1 and HS4 strains, and conclude that monitoring of such subgroups could provide a novel basis for future epidemiological surveillance of C. jejuni.

Antibody cross-reactivities between gangliosides and lipopolysaccharides of Campylobacter jejuni serotypes associated with Guillain-Barré syndrome

Ganglioside-antibodies produced subsequent to Campylobacter jejuni infection may play a role in the pathogenesis of the neurological disorder Guillain-Barré syndrome (GBS). Since lipopolysaccharides (LPS) of certain C. jejuni serotypes associated with GBS (O:2, O:4, O:19) exhibit structural mimicry of gangliosides in their core oligosaccharides, we investigated antibody and ligand cross-reactivities between gangliosides and LPS of these C. jejuni serotypes. GM1-antibody reacted with O:19 LPS reflecting GM1 mimicry by the O:19 core oligosaccharide. On the other hand, asialoGM1-antibody bound to O:2 and O:19 LPS indicating a shared epitope not dependent on ganglioside mimicry. Serum IgA from GBS patients after C. jejuni infection reacted with gangliosides, predominantly GM1, and LPS of all three serotypes. Cholera toxin (GM1 ligand) recognized O:4 and O:19 LPS, whereas peanut agglutinin (Galβ1-3GalNAc ligand) recognized LPS of all three serotypes, thereby confirming structural mimicry. These results suggest that LPS from certain C. jejuni strains may function as cross-reactive antigens for anti-ganglioside B cells.

Chemical Structures of the Core Region of Campylobacter Jejuni O:3 Lipopolysaccharide and an Associated Polysaccharide

The complete structure for the core oligosaccharide region of the water-insoluble low-M(r) lipopolysaccharide of Campylobacter jejuni serotype O:3 from phenol/water extraction of bacterial cells was assigned through studies on derivatives of the liberated oligosaccharide. Structure determinations were performed using 1H-NMR and 31P-NMR spectroscopies, methylation analysis supported by fast-atom-bombardment mass spectrometry, and Smith degradation experiments. It was concluded that the complete chains in the core oligosaccharide had the following structure in which a proportion of the terminal residues were phosphorylated: [formula: see text] From a similar series of experiments, it was concluded that an associated polysaccharide, which was isolated from the water phase of the phenol/water extracts, had the following repeating unit in which a proportion of the previously unknown L-glycero-D-ido-heptose (L-alpha-D-ido-Hep) residues were present as 3-hydroxypropanoyl esters, and were not covalently linked to the lipopolysaccharide: [formula see: text]

Molecular subtyping scheme for serotypes HS1 and HS4 of Campylobacter jejuni

We describe a molecular subtyping scheme for two principal O (heat-stable [HS]) serotypes of Campylobacter jejuni, HS1 and the HS4 complex. A 16S rRNA gene-specific probe confirmed that almost all the C. jejuni strains had three copies of this gene, and strains could be assigned with complete typeability to 1 of 16 combined (Pst1 and HaeIII) 16S ribotypes. Macrorestriction profiles (mrps) consisting of up to 10 SmaI fragments from approximately 40 to approximately 480 kbp were resolved by pulsed-field gel electrophoresis (PFGE). There were 11 mrps among the HS1 strains and 9 mrps among HS4 strains which corresponded to valid types--they occurred in multiple isolates, hosts, places, and times. There were 14 additional single-strain mrp fingerprints in HS1 and 20 in HS4. PFGE exhibited complete typeability when formaldehyde fixation of cells was employed, and PFGE was generally more differential than ribotyping. The data presented elucidate a high-resolution genotypic subtyping scheme for these common subspecific phenotypes of C. jejuni, which is both coherent and efficient for epidemiological purposes.

Lipopolysaccharides of Campylobacter jejuni serotype O:19: structures of O antigen chains from the serostrain and two bacterial isolates from patients with the Guillain-Barré syndrome.

An O antigenic polysaccharide was liberated from the lipopolysaccharide of high M(r) from Campylobacter jejuni serotype O:19 by acetic acid hydrolysis of the ketosidic linkage to lipid A. The structure of the polysaccharide was established in several one- and two-dimensional 1H and 13C NMR experiments, fast atom bombardment mass spectrometry and methylation linkage analysis of the permethylated glycan and its degradation products. It is concluded that the glycan is a derivative of hyaluronic acid in which the beta-D-glucuronic acid residues in the alternating sequence [-4)-beta-D-GlcA-(1-->3)-beta-D-GlcNAc-(1]n are present as amides of 2-amino-2-deoxyglycerol. Parallel experiments were performed on O antigens liberated from lipopolysaccharides of high M(r) from bacterial isolates that had been obtained from two patients who subsequently developed the Guillain-Barré syndrome. Within the limits of structural analysis by NMR spectroscopy and methylation linkage analysis, both these O antigens were identical to that from the serostrain.

Lipopolysaccharides of Campylobacter jejuni serotype O:19: structures of core oligosaccharide regions from the serostrain and two bacterial isolates from patients with the Guillain-Barré syndrome.

Lipopolysaccharides from phenol-water extraction of cells of Campylobacter jejuni serotype O:19 were separated into a water-soluble gel of low M(r) and a water-soluble component of high M(r). Acetic acid hydrolysis of the ketosidic linkages to lipid A furnished respectively a core oligosaccharide, the structure of which is reported herein, and an O antigenic polysaccharide. Structural investigations were performed on the O-deacetylated lipopolysaccharide of low M(r), the liberated core oligosaccharide and the various products from removal of neuraminic acid and phosphate residues, and from the Smith degradation. It is concluded that the lipopolysaccharide from the serostrain has a core region with two types of closely related oligosaccharide chains showing striking homologies with gangliosides, the first with a single N-acetylneuraminic acid residue in an outer chain resembling GM1 and the second with two N-acetyl-neuraminic acid residues with a terminal region resembling GD1a. Similar experiments were carried out on lipopolysaccharides of low M(r) from bacterial isolates OH 4384 and OH 4382 serotyped as O:19 that had been obtained from two patients who subsequently developed the Guillain-Barré syndrome. The core oligosaccharide region of lipopolysaccharide from the former isolate differed only slightly from that of the serostrain, whereas that from the latter isolate was distinctly shorter.

Diastereoselectivity in the synthesis of D-glycero-D-aldoheptoses by 2-trimethylsilylthiazole homologation from hexodialdo-1,5-pyranose derivatives

An exploration of the synthesis of D-glycero-D-altro-heptose, a constitutent of O antigen chains in lipopolysaccharides from Campylobacter jejuni serotypes O:23 and O:36 led to a study of the 2-trimethylsilylthiazole homologation procedure for heptose synthesis. In contrast to the diastereoselective formation of a 1,2:3,4-di-O-isopropylidene-D-glycero-α-D-galacto-heptopyranose derivative from 1,2:3,4-di-O-isopropylidene-α-D-galacto-hexodialdo-1,5-pyranose, methyl 2,3,4-tri-O-benzyl-D-hexodialdo-1,5-pyranosides with the gluco and manno configurations showed no preference for the formation of compounds with the D-glycero configuration. Attempts to achieve high diastereoselectivity in the conversion of L-glycero into the D-glycero isomers by oxidation at C-6 followed by reduction with L-selectride were unsuccessful with the thiazole adducts, but the desired products were formed in similar reactions of methyl 2,3,4-tri-O-benzyl-7-O-tert-butyldimethylsilyl-D-heptopyranosides. The approach to homologation in the altro series was thwarted by epimerization at C-5 in the attempted formation of methyl 2,3,4-tri-O-benzyl-α-D-altro-hexodialdo-1,5-pyranoside. The successful synthesis of methyl D-glycero-α-D-altro-heptopyranoside from methyl α-D-glucopyranoside was achieved by homologation followed by configurational alteration from the D-gluco to the D-altro series.