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MeSH: hemaglutinace-účinky léků

7 záznamů v PubMed Filtry

Článek

Fucosylated inhibitors of recently identified bangle lectin from Photorhabdus asymbiotica

Paulíková, Gita
Autor Paulíková, Gita ORCID Central European Institute of Technology, Masaryk University, Brno, Czech Republic National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Brno, Czech Republic
Houser, Josef
Autor Houser, Josef ORCID Central European Institute of Technology, Masaryk University, Brno, Czech Republic National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Brno, Czech Republic
Kašáková, Martina
Autor Kašáková, Martina Department of Chemistry of Natural Compounds, University of Chemistry and Technology, Prague, Czech Republic
Oroszová, Beáta
Autor Oroszová, Beáta Department of Chemistry of Natural Compounds, University of Chemistry and Technology, Prague, Czech Republic
Bertolotti, Benedetta
Autor Bertolotti, Benedetta ORCID Department of Chemistry of Natural Compounds, University of Chemistry and Technology, Prague, Czech Republic
Parkan, Kamil
Autor Parkan, Kamil ORCID Department of Chemistry of Natural Compounds, University of Chemistry and Technology, Prague, Czech Republic
Moravcová, Jitka
Autor Moravcová, Jitka Department of Chemistry of Natural Compounds, University of Chemistry and Technology, Prague, Czech Republic
Wimmerová, Michaela
Autor Autorita ORCID Central European Institute of Technology, Masaryk University, Brno, Czech Republic. michaw@chemi.muni.cz National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Brno, Czech Republic. michaw@chemi.muni.cz Department of Biochemistry, Faculty of Science, Masaryk University, Brno, Czech Republic. michaw@chemi.muni.cz

Scientific reports. 2019 Oct 17 ; 9 (1) : 14904. [epub] 20191017

Sci Rep
ISSN 2045-2322
Zdroj

A recently described bangle lectin (PHL) from the bacterium Photorhabdus asymbiotica was identified as a mainly fucose-binding protein that could play an important role in the host-pathogen interaction and in the modulation of host immune response. Structural studies showed that PHL is a homo-dimer that contains up to seven L-fucose-specific binding sites per monomer. For these reasons, potential ligands of the PHL lectin: α-L-fucopyranosyl-containing mono-, di-, tetra-, hexa- and dodecavalent ligands were tested. Two types of polyvalent structures were investigated - calix[4]arenes and dendrimers. The shared feature of all these structures was a C-glycosidic bond instead of the more common but physiologically unstable O-glycosidic bond. The inhibition potential of the tested structures was assessed using different techniques - hemagglutination, surface plasmon resonance, isothermal titration calorimetry, and cell cross-linking. All the ligands proved to be better than free L-fucose. The most active hexavalent dendrimer exhibited affinity three orders of magnitude higher than that of standard L-fucose. To determine the binding mode of some ligands, crystal complex PHL/fucosides 2 - 4 were prepared and studied using X-ray crystallography. The electron density in complexes proved the presence of the compounds in 6 out of 7 fucose-binding sites.

Článek

Microscopy examination of red blood and yeast cell agglutination induced by bacterial lectins

PloS one. 2019 ; 14 (7) : e0220318. [epub] 20190725

PLoS One
ISSN 1932-6203
Zdroj

Lectins are a group of ubiquitous proteins which specifically recognize and reversibly bind sugar moieties of glycoprotein and glycolipid constituents on cell surfaces. The mutagenesis approach is often employed to characterize lectin binding properties. As lectins are not enzymes, it is not easy to perform a rapid specificity screening of mutants using chromogenic substrates. It is necessary to use different binding assays such as isothermal titration calorimetry (ITC), surface plasmon resonance (SPR), microscale thermophoresis (MST), enzyme-linked lectin assays (ELLA), or glycan arrays for their characterization. These methods often require fluorescently labeled proteins (MST), highly purified proteins (SPR) or high protein concentrations (ITC). Mutant proteins may often exhibit problematic behaviour, such as poor solubility or low stability. Lectin-based cell agglutination is a simple and low-cost technique which can overcome most of these problems. In this work, a modified method of the agglutination of human erythrocytes and yeast cells with microscopy detection was successfully used for a specificity study of the newly prepared mutant lectin RS-IIL_A22S, which experimentally completed studies on sugar preferences of lectins in the PA-IIL family. Results showed that the sensitivity of this method is comparable with ITC, is able to determine subtle differences in lectin specificity, and works directly in cell lysates. The agglutination method with microscopy detection was validated by comparison of the results with results obtained by agglutination assay in standard 96-well microtiter plate format. In contrast to this assay, the microscopic method can clearly distinguish between hemagglutination and hemolysis. Therefore, this method is suitable for examination of lectins with known hemolytic activity as well as mutant or uncharacterized lectins, which could damage red blood cells. This is due to the experimental arrangement, which includes very short sample incubation time in combination with microscopic detection of agglutinates, that are easily observed by a small portable microscope.

MeSH
aglutinace účinky léků MeSH
aglutinační testy * metody MeSH
bakteriální proteiny farmakologie MeSH
erytrocyty cytologie účinky léků MeSH
hemaglutinace účinky léků MeSH
hemolýza účinky léků MeSH
kvasinky cytologie účinky léků MeSH
lektiny farmakologie MeSH
lidé MeSH
mikroskopie MeSH
povrchová plasmonová rezonance MeSH
proteiny z Escherichia coli farmakologie MeSH
Saccharomyces cerevisiae cytologie účinky léků MeSH
Check Tag
lidé MeSH
Publikační typ
časopisecké články MeSH
práce podpořená grantem MeSH
Názvy látek
bakteriální proteiny MeSH
lektiny MeSH
proteiny z Escherichia coli MeSH

Článek

A phase III, randomized, open-label study to assess the tolerability and immunogenicity of an H5N1 influenza vaccine administered to healthy adults with a 1-, 2-, 3-, or 6-week interval between first and second doses

Clinical therapeutics. 2010 Dec ; 32 (13) : 2186-97.

Clin Ther
ISSN 1879-114X | 0149-2918
Zdroj

BACKGROUND: Preparedness for an H5N1 influenza pre-pandemic requires effective and well-tolerated emergency vaccination strategies that provide both pandemic strain-specific and heterologous protection. OBJECTIVES: This was a pivotal study for the regulatory approval process for a candidate MF59-adjuvanted H5N1 vaccine. Its goals were to identify the preferred primary 2-dose vaccination schedule in adults and to assess whether the vaccine met European Committee for Medicinal Products for Human Use (CHMP) licensure criteria. METHODS: Healthy volunteers aged 18 to 60 years received 1 of 4 randomized schedules in which the 2 doses of vaccine were separated by a 1-, 2-, 3-, or 6-week interval. Three blood samples (~20 mL(-1)) were obtained from each subject: the first sample, immediately before administration of the first dose of vaccine; the second, immediately before administration of the second dose; and the third, 21 days after administration of the second dose. Hemagglutination inhibition (HI), microneutralization (MN), and single radial hemolysis (SRH) were assayed after each dose. Immunogenicity was assessed based on the CHMP licensure criteria for annual influenza vaccines (number of seroconversions or significant increase in HI titer >40%; mean geometric increase >2.5; and proportion of subjects achieving an HI titer ≥40 or SRH titer >25 mm(2) should be >70% [seroprotection]). Subjects recorded all adverse events occurring within 7 days of vaccine administration; information on any serious adverse events was collected throughout the study (duration, 202 days). RESULTS: All study participants (N = 240) were white, with a mean age of 33 years and a mean body mass index of 24.6 kg/m(2). Equal numbers of men and women were assigned to each vaccination schedule. The CHMP criterion for seroprotection was achieved when the 2 doses of vaccine were separated by 2 (76%), 3 (72%), and 6 (79%) weeks; similar results were obtained on MN and SRH analysis. On the SRH analysis, the candidate vaccine showed a heterologous immune response to the H5N1/turkey/Turkey/1/05 (NIBRG-23; clade 2) influenza antigen. The vaccine met 2 of the 3 European licensure criteria, with seroconversion rates of 69% and 65% in the groups assigned to a 2- and 3-week interval between doses, respectively, and geometric mean ratios of 4.3 and 4.5. There were no serious adverse events related to vaccination. The most common adverse events reported within 7 days of the first and second doses of vaccine were mild to moderate injection-site pain (63%-73% and 34%-48%, respectively) and fatigue (25%-30% and 13%-24%). CONCLUSIONS: Two 7.5-μg doses of MF59-adjuvanted H5N1 influenza vaccine given 2, 3, or 6 weeks apart afforded H5N1-specific immunity and met the CHMP licensure criterion for seroprotection in these healthy volunteers. Clinically relevant levels of heterologous immunity were observed when the 2 doses of vaccine were administered either 2 or 3 weeks apart; however, the licensure criterion for seroprotection was not met in this case.

Článek

Effects of insect hormones on hemagglutination activity in two members of the Culex pipiens complex

Experimental parasitology. 2002 Jan ; 100 (1) : 75-9.

Exp Parasitol
ISSN 0014-4894
Zdroj

Effects of methoprene and 20-hydroxyecdysone on the development and hemagglutination activity (HA) were studied in both sexes of two members of the Culex pipiens complex-anautogenous C. p. quinquefasciatus and autogenous C. p. molestus. Juvenile hormone analogue (methoprene) and 20-hydroxyecdysone caused developmental changes in both mosquito strains. High larval mortality, prolongation of intermolt period in each larval instar and in the pupal stage, and morphological changes in the larval-pupal and pupal-adult transformations were also observed. Developmental changes were accompanied with some differences in the HA. HA was found in both sexes of both experimental mosquito strains. The juvenile hormone analogue used in the larval stage caused significant decrease of HA in the gut of adults of both sexes. On the other hand, 20-hydroxyecdysone decreased HA only in the female gut. Results obtained indicate that HA depends on the sex, the studied organ, and the level of hormones.

Článek

Preservative-mediated changes of the surface properties of Escherichia coli

Folia microbiologica. 1996 ; 41 (2) : 159-64.

Folia Microbiol (Praha)
ISSN 0015-5632
Zdroj

The effectiveness of two commonly used preservatives, sodium benzoate and potassium disulfite, was evaluated in terms of their bactericidal activity and capacity to induce changes in the surface properties of Escherichia coli isolated from commercial food preserves. Preservative treatment over a five-week test period resulted in controlling the multiplication of these organisms and causing a decline in cell-surface hydrophobicity, hemagglutinating ability and adherence capacity to rat intestinal cells of E. coli isolates. A loss in motility was also exhibited.