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Synthesis and macromolecular organization of gastrointestinal mucin

100%

Slomiany A., Slomiany B. L.

Journal of Physiology and Pharmacology

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1992

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tom 43

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nr 2

Mucus glycoproteins (mucins), the principal determinants of mucus protective qualities and mucosal defense, are studied extensively to define pathological aberrations in the relation to gastrointestinal disease and to develop the mucous barrier strengthening agents. Recent work from our laboratory provided evidence as to the initial stages of the gastrointestinal mucin synthesis, molecular size of the apomucin, its macromolecular organization and interaction with other elements of gastrointestinal mucus. Using monoclonal antibodies against apomucin (clone 1H7), O- glycosylated with N-acetylgalactosamine apomucin (clone 2B4), and that against carboxyl terminal of the apomucin (clone 3G12), the mucin synthesizing polysomes were isolated and glycosylated peptides ranging in size from 6-60kDa identified. The in vitro synthesis in the cell-free system also afforded 60-64kDa products recognized by 1H7 and 3G12 antimucin MAbs. The obtained results provided evidence that the mucin core consists of 60kDa peptide which at cotranslational stage is O-glycosylated with N-acetylgalactosamine. Studies on mucin polymer assembly revealed that mucin preparations prepared by equilibrium density gradient centrifugation and Sepharose 2B chromatography (Mantle, M., Mantle, D., and Allen, A. (1981) Biochem. J. 195, 277-285) are not completely purified and contain DNA and extraneous proteins. The evidence was obtained that so called mucin “link protein”, 118kDa glycopeptide, is a N-glycosylated fragment of fibronectin, whereas the supposedly native undegraded mucin isolated by Carlstedt et al. (Biochem. J. (1983) 211, 13-22) was found to contain mucin-fibronectin-DNA complexes. The general picture that emerged from the studies is that the pure mucin consists of 60kDa glycosylated peptides only. The carboxyl terminal (8-12kDa fragment) of these peptides is not glycosylated (naked) and is responsible for mucin interaction with fibronectin and other fibronectin-like extracellular matrix proteins. While the formation of the mucosal coat depends on many other factors and extracellular components, our findings on mucin structure and interaction with the extracellular matrix proteins provide explanation as to the possible mechanism of mucin adherence to the epithelial surfaces.

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Occurrence of antibiotic resistant enterococci in clinical specimens from a pediatric hospital

72%

Rudy M., Zientara M., Bek T., Martirosian G.

Polish Journal of Microbiology

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2005

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tom 54

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nr 1

Enterococcal infection has become a major clinical problem and E. faecalis and E. faecium are the most frequently isolated species. However, the isolation of other species (E. casseliflavus, E. gallinarwn, E. durans) from clinical materials was reported recently. The aim of this study was to evaluate drug resistance of 97 species of enterococci isolated from clinical specimens of Upper Silesian Health Center of Child and Mother in Katowice. Each strain was tested for susceptibility to vancomycin, teicoplanin, aminoglycosides (gentamycin and streptomycin) and synercid (quinupristine/ dalfopristine) by the E-test method. Fifty three percent of studied enterococci demonstrated high level aminoglycoside resistance (HLAR) (MIC > 1024 μg/ml). Sixty three strains of E. faecalis were sensitive to vancomycin (MIC 1-4 μg/ml), but 5 strains demonstrated low sensitivity (3 strains with MIC = 6 μg/ml and 2 strains with MIC = 24 μg/ml). All studied enterococci were sensitive to teicoplanin (MIC < 2 μg/ml). A high percentage of E. faecium (70%) resistant to synercid was demonstrated (MIC = 2-24 μg/ml). Infection control and monitoring of antibiotic sensitivity among isolated hospital strains may prevent the transmission of resistant strains in a pediatric hospital.

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Characterization of glycopeptides, aminoglycosides and macrolide resistance among Enterococcus faecalis and Enterococcus faecium isolates from hospitals in Tehran

58%

Emaneini M., Aligholi M., Aminshahi M.

Polish Journal of Microbiology

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2008

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tom 57

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nr 2

The prevalence of glycopeptides, aminoglycosides and erythromycin resistance among Enterococcus faecalis and Enterococcus faecium was investigated. The susceptibility of 326 enterococcal hospital isolates to amikacin, kanamycin, netilmicin and tobramycin were determined using disk diffusion method. The minimum inhibitory concentration (MIC) of vancomycin, teicoplanin, gentamicin, streptomycin, and erythromycin were determined by microbroth dilution method. The genes encoding aminoglycoside modifying enzymes described as AMEs genes, erythromycin-resistant methylase (erm) and vancomycin-resistant were targeted by multiplex-PCR reaction. High level resistance (HLR) to gentamicin and streptomycin among enterococci isolates were 52% and 72% respectively. The most prevalent of AMEs genes were aac (6')-Ie aph (2") (63%) followed by aph (3') -IIIa (37%). The erythromycin resistance was 45% and 41% of isolates were positive for ermB gene. The ermA gene was found in 5% of isolates whereas the ermC gene was not detected in any isolates. The prevalence of vancomycin resistant enterococci (VRE) was 12% consisting of E. faecalis (6%) and E. faecium (22%) and all of them were VanA Phenotype. The results demonstrated that AMEs, erm and van genes are common in enterococci isolated in Tehran. Furthermore our results show an increase in the rate of vancomycin resistance among enterococci isolates in Iran.

Ograniczanie wyników

2 Polish Journal of Microbiology

1 Journal of Physiology and Pharmacology

1 Aligholi M.

1 Aminshahi M.

1 Bek T.

1 Emaneini M.

1 Martirosian G.

1 Rudy M.

1 Slomiany A.

1 Slomiany B. L.

1 Zientara M.

1 2008

1 2005

1 1992

Synthesis and macromolecular organization of gastrointestinal mucin

Occurrence of antibiotic resistant enterococci in clinical specimens from a pediatric hospital

Characterization of glycopeptides, aminoglycosides and macrolide resistance among Enterococcus faecalis and Enterococcus faecium isolates from hospitals in Tehran