Biomedical subjects

Wiesław Kaca

Publications and source records attributed to Wiesław Kaca.

8 recordsLinked to original sources

PubMed2006

Structures and serology of the O-antigens of Proteus strains classified into serogroup O17 and former serogroup O35.

INTRODUCTION: Bacteria of the genus Proteus are facultative pathogens which commonly cause urinary tract infections. Based on the serological specificity of the O-chain polysaccharide of the lipopolysaccharide (O-polysaccharide, O-antigen), strains of P. mirabilis and P. vulgaris have been classified into 60 serogroups. Studies on the chemical structure and serological specificity of the O-antigens aim at the elucidation of the molecular basis and improvement of the serological classification of these bacteria. MATERIALS AND METHODS: The O-polysaccharide was prepared by acetic acid degradation of the lipopolysaccharide isolated from dried bacterial mass of each strain by hot phenol/water extraction. (1)H- and (13)C-NMR spectroscopy was used for structural studies. Serological studies were performed with rabbit O-antisera using enzyme immunosorbent assay, passive hemolysis test, and the inhibition of reactions in these assays as well DOC-PAGE and Western blot. RESULTS: Four Proteus strains belonging to serogroups O17 and O35 were found to possess similar O-polysaccharide structures, in particular having the same carbohydrate backbone built up of tetrasaccharide repeating units. However, they differ in the presence or absence of additional substituents, such as phosphoethanolamine in P. mirabilis O17 and glucose in P. penneri O17, as well as in the pattern and degree of O-acetylation of various monosaccharide residues. Serological studies also showed close relationships between the O-antigens studied. CONCLUSIONS: Based on these data it is proposed to reclassify strain P. mirabilis PrK 61/57, formerly representing the O35 serogroup, into the serogroup O17 in the Kauffman-Perch classification system of Proteus.

Carbohydrate Conformation↗

PubMed2006

Synthetic peptides mimicking antigenic epitope of Helicobacter pylori urease.

Short peptides resembling the Helicobacter pylori urease antigen (UreB F8 Ser-Ile-Lys-Glu-Asp-Val-Gln-Phe) with deleted aspartic acid and glutamic acid residues, anchored through a triazine linker via the N-terminal moiety to cellulose plate were prepared. The peptides were used for binding of antibodies from sera of patients with medically confirmed atherosclerosis. Recognition of the peptides was also tested with anti-Jack beans urease antibodies. The important role of a Gly-Gly spacer separating the peptides from the cellulose support was shown. Different patterns of binding of antibodies from H. pylori infected patients and anti-Jack bean urease antibodies were observed only in the case of pentapeptides. The peptide Gly-Gly-Leu-Val-Phe-Lys-Thr was recognized by most of the tested sera.

Aspartic Acid↗

PubMed2003

Synthesis and induction of apoptosis in B cell chronic leukemia by diosgenyl 2-amino-2-deoxy-beta-D-glucopyranoside hydrochloride and its derivatives.

2-Acetamido-2-deoxy-D-glucose hydrochloride (D-glucosamine hydrochloride) has been used for the preparation of 1,3,4,6-tetra-O-acetyl-2-deoxy-2-trifluoroacetamido-beta- (4) and 2-tetrachlorophthalimido-alpha,beta-D-glucopyranose (6), which have been transformed into the appropriate bromides and the chloride. Both bromo and chloro sugars were used as a glycosyl donors for the glycosylation of diosgenin [(25R)-spirost-5-en-3beta-ol]. These condensations were conducted under mild conditions, using silver triflate as a promoter, and gave diosgenyl glycosides 9 and 12. Each of them was converted into diosgenyl 2-amino-2-deoxy-beta-D-glucopyranoside hydrochloride (11) and N-acylamido derivatives. The structures of all new glycosides were established by 1H and 13C NMR spectroscopy. These diosgenyl glycosides are the first saponins containing the D-glucosamine residue that have been synthesized. These compounds show promising antitumor activities. The synthetic saponins increase the number of apoptotic B cells, in combination with cladribine (2-CdA), that are isolated from chronic lymphotic leukemia (B-CLL) patients.

2-Chloroadenosine↗

PubMed2003

Lipopolysaccharide from Proteus mirabilis O29 induces changes in red blood cell membrane lipids and proteins.

Alterations in red blood cell (RBC) plasma membranes, i.e. in lipids and proteins, and osmotic fragility of these cells after treatment with Proteus mirabilis O29 endotoxin (lipolysaccharide (LPS)) were examined using a spin labelling method. At the highest concentration of LPS, insignificantly decreased fluidity of membrane lipids was observed. Changes in conformation of membrane proteins were determined by two covalently bound spin labels, 4-maleimido-2,2,6,6-tetramethylpiperidine-1-oxyl (MSL) and 4-iodoacetamido-2,2,6,6-tetramethylpiperidine-1-oxyl (ISL). The analysis of spectra of MSL and ISL showed modifications in membrane proteins in red blood cells treated with the highest concentration of lipopolysaccharide. On the other hand, in the case of isolated membranes, disturbances in membrane were observed for all concentrations of LPS. The alterations in membrane lipids and proteins are paralleled in a significant rise in osmotic fragility of RBCs upon endotoxin treatment. These results provide experimental evidence that P. mirabilis O29 LPS causes deleterious changes in membranes of human red blood cells. They show that action of lipopolysaccharide mainly concerns the membrane cytoskeleton.

Cell Membrane↗

PubMed2003

Tandem tetramer-based microsatellite fingerprinting for typing of Proteus mirabilis strains.

Two microsatellite tandem repeated tetramers, (GACA)(4) and (CAAT)(4), were used for Proteus mirabilis strain differentiation. The microsatellite-based PCR tests were applied for the examination of interstrain diversity for 87 P. mirabilis strains. Forty-six of the investigated strains were clinical isolates (5 were hospital isolates and 39 were outpatient clinic isolates); 42 strains were derived from the Kauffmann-Perch collection of laboratory strains. Fingerprinting done with the tetramers had a high discrimination ability [0.992 and 0.940 for (GACA)(4) and (CAAT)(4), respectively]. The distributions of clinical isolates among well-defined laboratory strains, determined by numerical analysis (unweighted pair-group method with arithmetic averages; Dice similarity coefficient), proved their genetic similarity to reference strains in the Kauffmann-Perch collection. This analysis also indicated that it is possible to estimate some phenotypic properties of P. mirabilis clinical isolates solely on the basis of microsatellite fingerprinting.

Bacterial Typing Techniques↗

PubMed2003

Immunochemical studies on the O-antigens of Proteus mirabilis O23 and Proteus vulgaris O23.

Analysis by 1H and 13C nuclear magnetic resonance (NMR) spectroscopy demonstrated that the O-specific polysaccharides of Proteus mirabilis PrK 42/57 and P. vulgaris PrK 43/57 are structurally similar to that of P. vulgaris PrK 44/57 and different from the polysaccharide of P. mirabilis PrK 41/57 studied earlier. The lipopolysaccharides of these strains were tested using enzyme immunosorbent assay, passive hemolysis and Western blot with O-antisera against P. mirabilis 42/57 and P. vulgaris 43/57 and 44/57, as well as with cross-absorbed O-antisera. The chemical and serological data revealed the basis for combining the four strains into Proteus serogroup O23 and division of this serogroup to three subgroups, one for P. vulgaris 43/57 and 44/57 and two others for P. mirabilis 41/57 and 42/57.

Animals↗

PubMed2003

The factor C3 conversion in human complement by smooth Shigella flexneri lipopolysaccharides.

Shigella flexneri rods play an important role in human intestinal infections. In the presented studies we have shown that O-acetyl and glucose residues, substituted in main GalNAc-Rha chains of lipopolysaccharide (LPS) are important for the bactericidal effect of human serum. By dot-blot, immunoblotting and ELISA with immobilized LPS we have shown correlation of C3 fragments deposition and serum resistance. LPSs isolated from a serum-sensitive strain deposited more C3 fragments than LPSs from serum-resistant Shigella flexneri strains.

Blood Bactericidal Activity↗

PubMedDate not supplied

Synthesis and serological interactions of H. pylori urease fragment 321-339 n-terminally immobilized on the cellulose.

Antigenic epitopes F8 (SIKEDVQF) and UB-33 (UreB fragment with residues 321-339: CHHLDKSIKEDVQFADSRI) in H. pylori urease that induces neutralizing antibody production were prepared on the cellulose plate from N- to C-terminus using CDMT as a coupling reagent. Reaction of both epitopes with sera of patients with medically confirmed atherosclerosis was studied. Strong, selective reactions of both peptides with some patients sera were observed.

Amino Acid Sequence↗