Biomedical subjects

Iu A Knirel'

Publications and source records attributed to Iu A Knirel'.

At least 19 recordsLinked to original sources

PubMed2006

[Generation of vaccine strains of gram-negative bacteria with reduced adverse reactions].

The main shortcoming of the modem live and killed vaccines based on gram-negative bacterial strains is their ability to cause adverse reactions. The majority of the adverse reactions are associated with the effect of biological activity of lipopolysaccharide. The report covers the problems concerned with biogenesis of the lipid A, lipopolysaccharide structural component, responsible for its endotoxic activity, as well as with genes determining lipid A synthesis. The special attention is paid to gene-engineering technique for reduction of adverse reactions of vaccine strains that are based on the knock-out mutagenesis of genes waaM and/or waaN responsible for addition of lauroyl and myristoyl residues to the distal glucosamine unit lipid A, generating acyloxyacyl moieties.

Acyltransferases↗

PubMed1996

[Structure of a new lysine-containing O-specific polysaccharide from Proteus mirabilis O26].

The composition and structure of the O-specific polysaccharide chain of the bacterium Proteus mirabilis O26 lipopolysaccharide have been studied using one- and two-dimensional 1H- and 13C-NMR spectroscopy, including homonuclear correlation spectroscopy (COSY), H-detected 1H,13C heteronuclear multi-quantum coherence and rotating-frame nuclear Overhauser effect spectroscopy. It has been found that the polysaccharide is acidic due to the presence of D-galacturonic acid (D-GalA) residues, part of which are O-acetylated, while the other part form an amide with the alpha-amino group of L-lysine and is built up of tetrasaccharide repeating units having the following structure: [formula: see text] The P. mirabilis O26 polysaccharide is structurally similar to the O-specific polysaccharide of P. mirabilis O28 studied earlier by us and containing amides of D-galacturonic acid with L-lysine and L-serine.

Amides↗

PubMed1996

[Structure of the O-specific polysaccharide from Proteus mirabilis O30].

Based on acid hydrolysis, methylation, and one- and two-dimensional 1H- and 13C-NMR spectroscopy, including homonuclear and 1H, 13C heteronuclear correlation spectroscopy (COSY) and rotating-frame nuclear Overhauser effect spectroscopy (ROESY); it was found that the O-specific polysaccharide chain of the lipopolysaccharide of the bacterium Proteus mirabilis O30 is a hexosamino-glucuronan built up of tetrasaccharide repeating units having the following structure: [formula: see text] The degree of O-acetylation of 2-acetamido-2-deoxyglucose is about 70%.

Carbohydrate Sequence↗

PubMed1996

[Structure of the O-specific polysaccharide chain from Burkholderia (Pseudomonas) solanacerum ICMP 750, 8093, 8115, 7864, and 7945 lipopolysaccharides].

Lipopolysaccharides (LPS) have been isolated from the cells of phytopathogenic bacteria Burkholderia (Pseudomonas) solanacearum strains (representatives of I, II and IV biovars) using mild acid hydrolysis followed by gel permeation chromatography of carbohydrate residues on Sephadex G-50 to yield five O-specific polysaccharides (O-PS). The O-PS structures were established by 13C-NMR spectroscopy. It has been found that O-PS have a linear or branched structure. The former represents a tetrasaccharide comprising three L-rhamnose residues and one N-acetylglucosamine residue. The differences between the strains are in the configuration (alpha or beta) and type [(1 --> 2) or (1 --> 3)] of the link between D-GtcpNAc and L-Rhap. The branched structure represents a xylosylated version of the linear structure and consists of pentasaccharide repeating units. The bacterial strains under study may be represented by multiple structural types, O-PS, involving both linear and branched repeating units. There is no correlation between the O-PS structure and strain specificity for any particular plant host.

Burkholderia↗

PubMed1996

[Structure of O-specific polysaccharide from Proteus mirabilis O10, containing a new component of O-antigens--L-altruronic acid].

An acidic O-specific polysaccharide was obtained by mild acid degradation of the lipopolysaccharide of Proteus mirabilis O10 and studied after full acid hydrolysis and carboxyl reduction by 1H- and 13C-NMR spectroscopy, including two-dimensional correlation spectroscopy (COSY), H-detected heteronuclear 1H,13C multi-quantum coherence (HMQC), and rotating-frame nuclear Overhauser effect spectroscopy (ROESY). It was found that the polysaccharide contains 2-acetamido-2-deoxy-D-glucose, 2-acetamido-2-deoxy-D-galactose, D-galacturonic acid, and L-altruronic acid, and the following structure of the branched tetrasaccharide repeating unit of the polysaccharide was established: [sequence: see text]

Carbohydrate Conformation↗

PubMed1995

[Structure of an acidic polysaccharide found in a bacteriolytic complex of lysoamidase].

A structural study of an acidic polysaccharide, a component of the lysoamidase bacteriolytic complex has been carried out. Analysis of the monosaccharide composition of the original polysaccharide, of the product of carboxyl groups reduction and of the 13C-NMR and 1H-NMR spectra of the original and the O-deacetylated polysaccharides using two-dimensional NMR spectroscopy has made it possible to establish the structure of the repeating trisaccharide unit of the polysaccharide as follows: [formula: see text] where ManNAcA and GalNAcA are 2-acetamido-2-deoxymannuronic acid and 2-acetamido-2-deoxygalacturonic acid, respectively. Also small amount of a neutral polysaccharide containing of rhamnose is present in the lysoamidase preparation.

Bacteria↗

PubMed1995

[Structure and properties of the common polysaccharide antigen of Pseudomonas aeruginosa bacteria (review)].

The review is devoted to a surface carbohydrate antigen of the bacterium Pseudomonas aeruginosa which is common for the majority of the species and has a lipopolysaccharide nature. The occurrence, detection, isolation, structure, expression on the cell surface, interaction with antibodies, an antibiotic and a bacteriophage as well as the immunotherapeutic potential of the common polysaccharide antigen are discussed.

Animals↗

PubMed1994

[Structure of lipopolysaccharides from gram-negative bacteria. III. Structure of O-specific polysaccharides].

Data on the composition and structure of O-antigens which represent polysaccharide chains of outer membrane lipopolysaccharides of gram-negative bacteria defining cell immunospecificity are reviewed with special reference to some structural features of O-antigens, such as masked regularity and occurrence in one microorganism of lipopolysaccharides with two structurally distinct polysaccharide chains. Antigenic relationships between the microorganisms belonging to different taxonomic groups are discussed.

Carbohydrate Sequence↗

PubMed1993

[Structure of the repeating unit of O-specific polysaccharide from Vibrio fluvialis].

O-Specific polysaccharide of Vibrio fluvialis, strain AQ-0002B, is built up to pentasaccharide repeating units contained of D-mannose, 2-acetamido-2-deoxy-D-glucose, 2-acetamido-2-deoxy-D-galactose, D-galacturonic acid and 3-0-[(R)-1'-carboxyethyl]-L-rhamnose (rhamnoactylic acid, Rha3Lac) residues. On the basis of methylation studies, solvolysis with HF, Smith degradation, 1H and 13C NMR-spectroscopy including homo- and heteronuclear correlation spectroscopy and NOE experiments, the following structure was suggested for the polysaccharide repeating unit: [formula: see text]

Carbohydrate Conformation↗

PubMed1993

[Antigenic polysaccharides of bacteria 38. Structure of O-antigens of Pseudomonas solanacearum ICMP 7942 and ICMP 8169].

The structures I and II were established for the O-antigens of Pseudomonas solanacearum ICMP 7942 and ICMP 8169, respectively, by means of NMR-spectroscopy, including 2D homonuclear shift-correlated spectroscopy (COSY), rotating-frame NOE spectroscopy (ROESY) and heteronuclear 13C, 1H multiquantum correlation spectroscopy (HMQC). In the polysaccharide of the ICMP 8169 strain substitution of the main chain by the xylose residue is non-stoichiometric, i.e. this antigen contains also the repeating units of the polysaccharide of the ICMP 7942 strain (the ratio II: I is approximately 3:1). [formula: see text]

Carbohydrate Sequence↗

PubMed1993

[Structural study of O-specific polysaccharides from Proteus mirabilis O28 and 3/6, containing amides of D-galacturonic acid with L-amino acids; C-methylation and beta-elimination at L-serine and L-threonine residues upon analysis using the methylation method].

Structures of the O-specific polysaccharides of Proteus mirabilis O28 and 3/6 were studied by partial acid hydrolysis followed by borohydride reduction and methylation and GLC/MS analysis of the resulting glycosyl alditol derivatives. C-Methylation and beta-elimination in serine and threonine attached to the carboxyl group of galacturonic acid were observed in the course of the methylation analysis.

Amino Acids↗

PubMed1993

[Structure of the repeating unit of acid polysaccharide from Alteromonas macleodii 2MM6].

An acidic polysaccharide from Alteromonas macleodii 2MM6 is shown to consist of tetrasaccharide repeating units containing D-galactose, 3-O-acetyl-2-acetamido-2-deoxy-D-glucose, 2-acetamido-2-deoxy-L-guluronic acid and 3,6-dideoxy-3-(4-hydroxybutyramido)-D-galactose residues. On the basis of sugar analysis, 1H and 13C NMR-spectroscopy data including NOE and one-dimensional HOHAHA experiments, the following structure was suggested for the polysaccharide repeating unit: [formula: see text] R: -CO-CH2-CH2-CH2-OH.

Carbohydrate Conformation↗

PubMed1993

[Structure of lipopolysaccharides from gram-negative bacteria. I. Common characteristics of lipopolysaccharides and lipid A structure (Review)].

The data on the structure and properties of outer membrane lipopolysaccharides of gram-negative bacteria are reviewed with special reference to the general organization of the lipopolysaccharide molecule and the structure of the lipid moiety (lipid A). The correlation between the structure of the lipopolysaccharides and lipid A and their biological properties and functions are discussed.

Carbohydrate Conformation↗

PubMed1993

[Structure of lipopolysaccharides from gram-negative bacteria. II. Core structure (Review)].

The review summarizes the data on the core structure of bacterial lipopolysaccharides (LPS) which represents an oligosaccharide binding the lipid moiety of the macromolecule to the O-antigenic polysaccharide chain. Both S-strains with complete LPS and R-mutants having various defects of the core biosynthesis are considered. The role of the core in the outer membrane functioning and manifestation of antigenic specificity of LPS is discussed.

Carbohydrate Conformation↗

PubMed1993

[Structure of the repeating link of the acid polysaccharide of Alteromonas haloplanktis KMM 156].

An acidic capsular and an O-specific polysaccharide were isolated from the marine microorganism Alteromonas haloplanktis KMM 156. Both polysaccharides have the identical structure and are built up of tetrasaccharide repeating units, containing two residues of L-rhamnose as well as a 2-acetamido-2-deoxy-D-glucose and a 3-O-[(R)-1-carboxyethyl]-D-glucose (Glc3Lac) residue. On the basis of methylation studies, 1H- and 13C-NMR-spectroscopy including nuclear Overhauser effect and two-dimensional heteronuclear 13C/1H correlation spectroscopy, the following structure was suggested for the polysaccharide repeating unit: [formula: see text]

Carbohydrate Sequence↗

PubMed1992

[SCAN program for structural analysis of linear polysaccharides based on 13C-NMR spectral data using personal computers].

A programme SCAN was elaborated for the 13C NMR--based structural analysis of regular polysaccharides, which represents our earlier programme (Lipkind G.M. et al. Carbohydr. Res. 1988. V. 175. No 1. P. 59-75) modified for IBM-PC-compatible personal computers. SCAN was successfully applied for the structural elucidation of 24 polysaccharides of bacterial origin. Optimal combinations of the computer-assisted method with other approaches for analysis of carbohydrates and scopes of application of the programme are discussed.

Carbohydrate Conformation↗

PubMed1991

[Problems of resistance of the causative agent of melioidosis to antibiotics].

It was shown that the pathogen causing melioidosis was highly resistant to antibiotics including beta-lactams. Antibiotic sensitive mutants of P. pseudomallei were isolated after mutagenesis induced by nitrosoguanidine. Permeability for 3H-tetracycline and tetracycline sensitivity of the mutant cells was respectively 3 and 20 times as high as those of the initial parent strain. Gas liquid chromatography revealed quantitative and qualitative changes in separate sugars of the lipopolysaccharide structure in antibiotic sensitive mutants as compared to the initial strain.

Anti-Bacterial Agents↗

PubMed1990

[Antigenic polysaccharides of bacteria. 37. Structure of the polysaccharide chain of Pseudomonas syringae pv.tabaci (serogroup VII) lipopolysaccharide].

The structure of the O-specific polysaccharide chain of Pseudomonas syringae pv. tabaci strain 223 (serogroup VII) lipopolysaccharide was established on the basis of one- and two-dimensional 1H NMR analysis, 13C NMR analysis and calculation of optical rotation. The structure determined by the non-destructive way was confirmed by acid hydrolysis and methylation. (Sequence: see text). O-Antigen of the strain studied is similar in structure and serological properties to O-antigens of Pseudomonas syringae strains belonging to serogroup I.

Antigens, Bacterial↗