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M B Perry

Publications and source records attributed to M B Perry.

At least 55 records · Page 3Linked to original sources
PubMed1998

Activities of SV40 T antigen necessary for the induction of tetraploid DNA content in permissive CV-1 cells.

To determine the role of SV40 T antigen in stimulating multiple rounds of DNA synthesis in permissive cells, CV-1 cells were transfected with plasmids expressing mutant or wt T antigen in the presence or absence of the SV40 origin of replication. Induction of cells with > G2 DNA content (tetraploid DNA content) and levels of T antigen protein were detected and analyzed by flow cytometry. The mutant T antigen proteins demonstrated the expected phenotypes as determined by immunoprecipitation. Elevated levels of T antigen protein were detected in each transfection, but full-length T antigen alone was responsible for the tetraploid DNA content. The studies show that full-length T antigen with point mutations to reduce binding to the cellular proteins p53 and/or Rb were capable of inducing > G2 DNA content though the induction by these mutants was greatly enhanced by the presence of the SV40 origin of replication. Truncated T antigen (aa 1-259) could induce cells with tetraploid DNA content only in the presence of the SV40 origin of replication and the absence of Rb binding. These studies suggest that multiple functions of T antigen are involved in the stimulation of the second round of cellular DNA synthesis.

Animals↗
PubMed1998

Glucosylated N-acetyllactosamine O-antigen chain in the lipopolysaccharide from Helicobacter pylori strain UA861.

The O-antigen chain from the lipopolysaccharide of Helicobacter pylori strain UA861 was determined to be composed of an elongated type 2 N -acetyllactosamine backbone, -[-->3)-beta-D-Gal-(1-->4)-beta-D-GlcNAc-(1-]n-->, with approximately half of the GlcNAc units carrying a terminal alpha-d-Glc residue at the O -6 position. The O-chain of H.pylori UA861 was terminated by a N -acetyllactosamine [beta-D-Gal-(1-->4)-beta-D-GlcNAc] (LacNAc) epitope and did not express terminal Lewis X or Lewis Y blood-group determinants as previously found in other H.pylori strains. The absence of terminal Lewis X and Lewis Y blood-group epitopes and the replacement of Fuc by Glc as a side chain in the O-chain of H.pylori UA861 represents yet another type of lipopolysaccharide structure from H.pylori species. These structural differences in H.pylori lipopolysaccharide molecules carry implications with regard to possible different pathogenic events between strains and respective hosts.

Amino Sugars↗
PubMed1998

Susceptibility of three strains of conventional adult mice to intestinal colonization by an isolate of Escherichia coli O157:H7.

Three mouse strains were assessed for their susceptibility to intestinal colonization by a strain of the enteric bacterial pathogen Escherichia coli O157:H7. Following intragastric inoculation of E. coli O157:H7, the intestines of young adult female CD1, BALB/c, and C57BL/6 mice became colonized, as evidenced by faecal shedding of the pathogen for periods of up to 5 weeks. None of the three mouse strains examined developed overt disease in response to colonization by the organism. Following clearance of the primary inoculum, BALB/c mice, but not CD1 or C57BL/6 mice, appeared to acquire enhanced resistance to recolonization by E. coli O157:H7, as evidenced by a decreased faecal shedding period. This enhanced resistance correlated with the presence and persistence of immunoglobulin A, but not immunoglobulin G, in the serum and faeces directed against the O157 antigen. The implications of these findings to vaccine development against E. coli O157:H7 are discussed.

Animals↗
PubMed1997

Structural analysis of the lipopolysaccharide from Vibrio cholerae serotype O22.

The structure of the lipopolysaccharide (LPS) from Vibrio cholerae serogroup O22 was elucidated. The LPS was subjected to a variety of degradative procedures, and the structures of the purified products were established by monosaccharide and methylation analyses, nuclear magnetic resonance (NMR) spectroscopy, and mass spectrometry. The following structure for the complete LPS molecule was determined on the basis of the combined data from these experiments. [formula: see text] The elucidation of this structure provided a chemical basis for the serological cross-reactions observed between this strain and V. cholerae serogroup O139.

Carbohydrate Conformation↗
PubMed1997

Identification of the common antigenic determinant shared by Streptococcus pneumoniae serotypes 35A and 20 capsular polysaccharides--structural analysis of the Streptococcus pneumoniae serotype 35A capsular polysaccharide.

The specific polysaccharide antigen of Streptococcus pneumoniae serotype 35A was shown, by a combination of one- and two-dimensional NMR methods and chemical analyses, to be a high-molecular-mass polymer composed of D-galactose, D-glucose, mannitol, and phosphate (3:1:1:1). The pentasaccharide repeating unit is polymerized through phosphate diester linkages to give the structure, [formula in text] O-Acetyl substituents are present at positions 5 and 6 of the 3)-beta-D-Galf residue and at position 2 of the 6)-beta-D-Galf residue. The capsular polysaccharides of S. pneumoniae serotypes 20 and 35A both contain the disaccharide unit -->3)-beta-D-Galf-(1-->3)-beta-D-Glcp-(1--> which is the probable structural determinant responsible for the serological cross reactivity of the two polysaccharides.

Bacterial Capsules↗
PubMed1997

The lipopolysaccharide of Helicobacter mustelae type strain ATCC 43772 expresses the monofucosyl A type 1 histo-blood group epitope.

The lipopolysaccharide of Helicobacter mustelae type strain ATCC 43772 was obtained by phenol-water extraction of bacterial cells. Structural investigations were made on the lipid A free saccharide moiety released from the lipopolysaccharide by mild acetic acid hydrolysis. Nuclear magnetic resonance, gas liquid chromatography-mass spectrometry and fast atom bombardment-mass spectrometry were employed in the characterization of products from chemical manipulations. A monoclonal antibody specific for blood group A reacted strongly with lipopolysaccharide of H. mustelae. Chemical and serological data showed that the outer core region of the lipopolysaccharide from H. mustelae ATCC 43772 expresses the monofucosyl A type 1, alpha-D-GalNAc-(1-->3)-[alpha-L-Fuc-(1-->2]-beta-D-Gal-(1-->3)- beta-D-GlcNAc, blood group determinant, a mimic of animal cell surface glycolipids and glycoproteins.

Animals↗
PubMed1997

Specificity and functional activity of anti-Burkholderia pseudomallei polysaccharide antibodies.

The lipopolysaccharide (LPS) of Burkholderia pseudomallei, the causative agent of melioidosis, consists of two O-antigenic polysaccharides designated O-PS I and O-PS II. In this study, the O-PS specificity and functional activity of a protective polyclonal antiserum and an immunoglobulin M (IgM) monoclonal antibody were determined. The polyclonal antiserum recognized both O-PS I and O-PS II, while the monoclonal antibody was O-PS II specific. Both mediated phagocytic killing of B. pseudomallei by polymorphonuclear leukocytes. Patients acutely infected with B. pseudomallei also produced antibodies to the two O-PSs, but these antibodies were not produced by asymptomatic individuals from an area of endemicity who were seropositive by an indirect hemagglutination test using sonicated heat-killed whole organisms as antigen. IgM antibodies were detected only in patients with localized infection. IgG antibodies were detected in all acutely infected patients, but there was no significant difference in antibody levels among patients with localized infection, patients who survived septicemic illness, and patients who died from septicemic illness. Further analysis of the IgG response revealed production of IgG1 and IgG2 antibodies by all patient groups, while an IgG3 response was seen only in survivors of septicemic infection. IgG4 was not detectable even when a fivefold-lower serum dilution was used. Patient sera also mediated phagocytic killing by polymorphonuclear leukocytes, and the killing effect was enhanced by complement. These results suggest that antibodies to the LPS O-polysaccharides of B. pseudomallei are protective by promoting phagocytic killing. The antibodies develop during human infection and may facilitate clearance of the organisms, as seen in a diabetic rat model of B. pseudomallei infection.

Antibodies, Bacterial↗
PubMed1997

Structural characterization of the lipids A of three Bordetella bronchiseptica strains: variability of fatty acid substitution.

The structures of lipids A isolated from the lipopolysaccharides (LPSs; endotoxins) of three different pathogenic Bordetella bronchiseptica strains were investigated by chemical composition and methylation analysis, gas chromatography-mass spectrometry, nuclear magnetic resonance, and plasma desorption mass spectrometry (PDMS). The analyses revealed that the LPSs contain the classical lipid A bisphosphorylated beta-(1-->6)-linked D-glucosamine disaccharide with hydroxytetradecanoic acid in amide linkages. Their structures differ from that of the lipid A of Bordetella pertussis endotoxin by the replacement of hydroxydecanoic acid on the C-3 position with hydroxydodecanoic acid or dodecanoic acid and the presence of variable amounts of hexadecanoic acid. The dodecanoic acid is the first nonhydroxylated fatty acid to be found directly linked to a lipid A glucosamine. The lipids A were heterogeneous and composed of one to three major and several minor molecular species. The fatty acids in ester linkage were localized by PDMS of chemically modified lipids A. B. pertussis lipids A are usually hypoacylated with respect to those of enterobacterial lipids A. However, one of the three B. bronchiseptica strains had a major hexaacylated molecular species. C-4 and C-6' hydroxyl groups of the backbone disaccharide were unsubstituted, the latter being the proposed attachment site of the polysaccharide. The structural variability seen in these three lipids A was unusual for a single species and may have consequences for the pathogenicity of this Bordetella species.

Bordetella bronchiseptica↗
PubMed1997

Characterization of the capsular polysaccharide of Burkholderia (Pseudomonas) pseudomallei 304b.

Burkholderia (Pseudomonas) pseudomallei is the causative agent of melioidosis, a bacterial infection of considerable morbidity in areas of endemicity of Southeast Asia and northern Australia. Clinical isolates of B. pseudomallei have been demonstrated to produce a lipopolysaccharide (LPS) containing two separate and chemically distinct antigenic O polysaccharides against which infected patients produced antibodies. A putative capsular polysaccharide (CPS) has also been reported and is thought to be antigenically conserved based on results of serological studies with clinical B. pseudomallei isolates. In the present study, the CPS isolated from B. pseudomallei 304b from northeastern Thailand was found to have an [alpha]D of +99 degrees (water), was composed of D-galactose (D-Gal), 3-deoxy-D-manno-2-octulosonic acid (KDO), and O-acetyl 3:1:1), and was a linear unbranched polymer of repeating tetrasaccharide units having the following structure: -3)-2-O-Ac-beta-D-Galp-(1-4)-alpha-D-Galp-(1-3)-beta-D -Galp-(1-5)-beta-D-KDOp-(2-. Sera from 13 of 15 patients with different clinical manifestations of melioidosis but not normal controls recognize the CPS, which suggests that it is immunogenic and raises the possibility that it may have a role as a vaccine candidate and/or diagnostic agent.

Antibodies, Bacterial↗
PubMed1997

Structural characterization of the serotype O:5 O-polysaccharide antigen of the lipopolysaccharide of Escherichia coli O:5.

The structure of the antigenic O-polysaccharide component of the smooth lipopolysaccharide produced by Escherichia coli serotype O:5 was investigated by composition, methylation, and periodate oxidation methods, and by 1D and 2D nuclear magnetic resonance spectroscopy. The antigenic O-chain was determined to be a high molecular weight polysaccharide composed of repeating tetrasaccharide units containing 2-acetamido-2-deoxy-D-galactose, D-galactose, D-ribose, and 3-acetamido-3,6-dideoxy-D-glucose and having the structure -[-4)-beta-D-Galp-(1-3)-alpha-D-GalpNAc-(1-4)-beta-D-Quinp3NAc-(1- 3)-beta-D-Ribf-(1-]-.

Carbohydrate Conformation↗
PubMed1996

Structures of the antigenic O-polysaccharides of lipopolysaccharides produced by Actinobacillus actinomycetemcomitans serotypes a, c, d and e.

Actinobacillus actinomycetemcomitans is a gram-negative capnophilic coccobacillus that has been implicated in the etiology of certain forms of early-onset periodontitis as well as non-oral infections, mostly bacterial endocarditis. Five distinct serotypes of A. actinomycetemcomitans have been described. Although the O-polysaccharide (O-PS) of lipopolysaccharide (LPS) has been shown to define the serologic specificity for this species, only the structure of the O-PS of serotype b has been characterized. The focus of the current study was to define the structures of the O-PS of A. actinomycetemcomitans serotypes a, c, d and e. Structure determination was accomplished through the use of methylation, periodate oxidation, and one-dimensional and two-dimensional NMR methods. The O-PS of A. actinomycetemcomitans (OMZ-542) serotype d had [alpha]D +15 degrees and was composed of D-glucose, D-mannose and L-rhamnose (L-Rha) in a molar ratio of 1:2:1. Methylation, periodate oxidation, and two-dimensional 1H-NMR and 13C-NMR studies showed that the antigenic O-PS was a high-molecular-mass polymer composed of repeating tetrasaccharide units with the structure: [formula: see text] The O-PS of the LPS produced by A. actinomycetemcomitans (ATCC 29523) serotype a had [alpha]D +150 degrees and was found to contain 6-deoxy-D-talose (6dTalp) and O-acetyl (2:1) and was a high-molecular-mass polymer composed of O-acetyl-substituted repeating disaccharide units with the structure: [formula: see text] The O-PS of the LPS of A. actinomycetemcomitans (SUNY 67) serotype c had [alpha]D -170 degrees and was composed of 6-deoxy-L-talose and O-acetyl (2:1). Structural analysis showed that the O-PS was a high-molecular-mass polymer of repeating disaccharide units with the structure: [formula: see text] The O-PS of the LPS of A. actinomycetemcomitans (OMZ 534) serotype e had [alpha]D +57 degrees and was composed of 2-acetamido-2-deoxy-D-glucose and L-rhamnose (1:1) and by chemical and NMR analysis was found to be a polymer of repeating disaccharide units with the structure: -->4)-alpha-D-GlcpNAc-(1-->3)-alpha-L-Rhap-(1-->.

Aggregatibacter actinomycetemcomitans↗
PubMed1996

Structural analysis of the lipopolysaccharide from Vibrio cholerae O139.

The lipopolysaccharide (LPS) from Vibrio cholerae O139 was deacylated with KOH. The following structure of the oligosaccharide resulting from this treatment was established on the basis of monosaccharide and methylation analyses, 1H, 13C and 31P 1D and 2D NMR experiments and 1D analogues of 3D NOESY-TOCSY and 3D TOCSY-NOESY experiments. [formula: see text] 'C' is a beta-L-threo-hex-4-enuronopyranosyl residue. Hep is L-glycero-D-manno-heptose, QuiN is 2-amino-2,6-dideoxy-D-glucose, GlcN is 2-amino-2-deoxy-D-glucose, Glc is D-glucose, Fru is D-fructose, and Kdo is 3-deoxy-D-manno-2-octulosonic acid. All sugars are pyranoses except fructose which is furanosidic. The fructose residue was localised after deacylation of the LPS with anhydrous hydrazine, methylation, acid methanolysis, and remethylation using deuterated iodomethane. The elucidation of this structure allowed for a direct comparison to the previously determined structure for Vibrio cholerae O1 lipid A-core region. The two structures are almost identical, and, therefore, this study is consistent with the genetic data for the biogenesis of strain O139 from O1. Furthermore, the identification of a structural analogue to the capsular polysaccharide of O139 in the outer core of the LPS in conjunction with the identification of colitose as a constituent of the LPS, provides additional evidence that the O-antigen and capsular polysaccharide of this strain may share the same repeat unit.

Carbohydrate Conformation↗
PubMed1996

Induction of tetraploid DNA content by mutant simian virus 40 T antigen that has reduced complex formation with p53.

The 402 mutants (DE, DH, DN) of simian virus (SV) 40 form reduced levels of p53-T antigen complexes or no complexes in lytically infected cells (CV-1 cells) relative to wild-type (wt) virus when assayed by immunoprecipitation. When CV-1 cells were infected with the 402 mutants, the cells were induced into multiple rounds of DNA synthesis without mitosis, resulting in a large population of cells with > G2 (tetraploid) DNA content similar to wt virus. The levels of T antigen and p53 per cell that were determined by flow cytometry were similar to wt lytically infected cells, with the levels of T antigen increasing as the infection proceeded. The p53 increased as the levels of T antigen increased, similar to a wt infection. These studies demonstrate that, in lytically infected cells with reduced p53-T antigen complex formation, the cells are induced into multiple rounds of DNA synthesis.

Antigens, Polyomavirus Transforming↗
PubMed1996

Separation and characterization of O-deacylated lipooligosaccharides and glycans derived from Moraxella catarrhalis using capillary electrophoresis-electrospray mass spectrometry and tandem mass spectrometry.

Electrophoretic methods have been developed for the analysis of complex carbohydrates derived from lipooligosaccharides (LOS) of Moraxella catarrhalis using capillary electrophoresis coupled to electrospray mass spectrometry (CE-ESMS). Separation of lipooligosaccharides (LOS) arising from mild hydrazinolysis of the intact lipopolysaccharides (LPS) was achieved using aqueous ammonium formate, and enabled identification of sites of heterogeneity (phosphates, phosphoethanolamine, and pendant acyl groups) on either the lipid A or the core oligosaccharide. More complex mixtures of carbohydrates obtained from the complete deacylation and dephosphorylation of LOS were amendable to electrophoretic conditions using both anionic and cationic separation. In particular, electrophoretic conditions were developed which permitted resolution of closely related oligosaccharides according to the number of carbohydrate residues appended to the core structure. Structural characterization of carbohydrates and LOS released from the hydrazinolysis and acid hydrolysis treatment of the intact LPS was achieved using tandem mass spectrometry (MS-MS) for samples introduced by direct flow injection. Taken together, the combination of CE-ESI-MS and MS-MS analyses provided valuable information on the heterogeneity of the LOS population in which a significant level of variability was found mostly in the lipid A portion.

Acylation↗
PubMed1996

Characterization of the O-polysaccharide structure of lipopolysaccharide from Actinobacillus actinomycetemcomitans serotype b.

We previously reported that the serotype b antigen of Actinobacillus actinomycetemcomitans is a constituent of the polysaccharide region of lipopolysaccharide (LPS) and contains significant amount of the neutral sugars rhamnose and fucose (M. Wilson and R. Schifferle, Infect. Immun. 59:1544-1551, 1991). In the present study, we determined the structure of the O antigen of A. actinomycetemcomitans Y4 (serotype b) LPS. Aqueous phase LPS was obtained from a phenol-water extract of A. actinomycetemcomitans Y4. This material was found to react with rabbit polyclonal antiserum to serotype b but not with antisera specific for other A. actinomycetemcomitans serotypes. Analyses revealed that the O polysaccharide of Y4 LPS consists of a polymer of trisaccharide repeating units composed of D-Fuc, AL-Rha, and D-GalNAc residues. An identical structure was obtained for the O polysaccharide of LPS from A. actinomycetemcomitans JP2, another serotype b strain. These results indicate that the serotype b antigen of A. actinomycetemcomitans is defined by a trisaccharide repeating unit present in the O polysaccharide of LPS.

Aggregatibacter actinomycetemcomitans↗
PubMed1996

Structural characterization of the O-antigenic polysaccharide of Escherichia coli serotype 017 lipopolysaccharide.

The structure of the O-polysaccharide component of the lipopolysaccharide produced by Escherichia coli 017 (ATCC 23512) was determined by the use of methylation, periodate oxidation, one- and two-dimensional nuclear magnetic resonance spectroscopy, and mass spectrometric methods. The O-polysaccharide was found to be a high molecular weight polymer of repeating branched pentasaccharide units composed of D-mannose, D-glucose, and 2-acetamido-2-deoxy-D-glucose residues (3:1:1) and had the structure (formula: see text).

Carbohydrate Conformation↗
PubMed1995

Characterization of a lipopolysaccharide O antigen containing two different trisaccharide repeating units from Burkholderia cepacia serotype E (O2).

The O antigen of the lipopolysaccharide of Burkholderia cepacia serotype E (O2) was shown by a combination of methylation analysis, partial hydrolysis, NMR, and mass spectrometric methods to be a high molecular weight polysaccharide composed of two different trisaccharide repeating units in the ratio 2:1. The major trisaccharide component is composed of two alpha-D-mannopyranosyl and one beta-D-galactopyranosyl residues with the structure, [-->2)-alpha-D-Man p-(1-->2)-alpha-D-Man p-(1-->4)-beta-D-Gal p-(1-->]n The minor trisaccharide component is a D-mannan composed of two alpha- and one beta-D-mannopyranosyl residues with the structure, [-->2)-alpha-D-Man p-(1-->2)-alpha-D-Man p-(1-->3)-beta-D-Man p-(1-->]n

Carbohydrate Conformation↗