The Experts below are selected from a list of 189 Experts worldwide ranked by ideXlab platform
Jaume Piñol - One of the best experts on this subject based on the ideXlab platform.
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Gliding parameters, cell morphology and Hemadsorption of M. genitalium G37 wild type and MG_491 mutant strains.
2016Co-Authors: Luca Martinelli, Enrique Querol, Luis García-morales, Jaume Piñol, Ignacio Fita, Bárbara M. CalistoAbstract:Gliding parameters, cell morphology and Hemadsorption of M. genitalium G37 wild type and MG_491 mutant strains.
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Quantitative assessment of Mycoplasma Hemadsorption activity by flow cytometry.
PloS one, 2014Co-Authors: Luis García-morales, Manuela Costa, Enrique Querol, Luis González-gonzález, Jaume PiñolAbstract:A number of adherent mycoplasmas have developed highly complex polar structures that are involved in diverse aspects of the biology of these microorganisms and play a key role as virulence factors by promoting adhesion to host cells in the first stages of infection. Attachment activity of mycoplasma cells has been traditionally investigated by determining their Hemadsorption ability to red blood cells and it is a distinctive trait widely examined when characterizing the different mycoplasma species. Despite the fact that protocols to qualitatively determine the Hemadsorption or hemagglutination of mycoplasmas are straightforward, current methods when investigating Hemadsorption at the quantitative level are expensive and poorly reproducible. By using flow cytometry, we have developed a procedure to quantify rapidly and accurately the Hemadsorption activity of mycoplasmas in the presence of SYBR Green I, a vital fluorochrome that stains nucleic acids, allowing to resolve erythrocyte and mycoplasma cells by their different size and fluorescence. This method is very reproducible and permits the kinetic analysis of the obtained data and a precise Hemadsorption quantification based on standard binding parameters such as the dissociation constant Kd. The procedure we developed could be easily implemented in a standardized assay to test the Hemadsorption activity of the growing number of clinical isolates and mutant strains of different mycoplasma species, providing valuable data about the virulence of these microorganisms.
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Phenotype of the cI-6 and c30 mutants.
2013Co-Authors: Oscar Q. Pich, Enrique Querol, Raul Burgos, Jaume PiñolAbstract:(A) Colony morphology, (B) qualitative Hemadsorption activity and (C) scanning electron microscopy analysis of the cI-6 mutant. (D) Colony morphology, (E) qualitative Hemadsorption activity and (F) scanning electron microscopy analysis of the C30 mutant.
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Hemadsorption activity analysis.
2013Co-Authors: Oscar Q. Pich, Enrique Querol, Raul Burgos, Jaume PiñolAbstract:Qualitative Hemadsorption assay of the WT strain (A), the T192 mutant (B) and the T192C mutant (C). Colonies of the WT strain and the T192C mutant are fully covered by erythrocytes. In contrast, only the periphery of the T192 mutant colonies has erythrocytes bound.
Yoshihiro Kawaoka - One of the best experts on this subject based on the ideXlab platform.
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Neuraminidase Hemadsorption activity, conserved in avian influenza A viruses, does not influence viral replication in ducks.
Journal of virology, 1997Co-Authors: Darwyn Kobasa, M E Rodgers, Krisna Wells, Yoshihiro KawaokaAbstract:The N1 and N9 neuraminidase (NA) subtypes of influenza A viruses exhibit significant Hemadsorption activity that localizes to a site distinct from that of the enzymatic active site. To determine the conservation of Hemadsorption activity among different NAs, we have examined most of the NA subtypes from avian, swine, equine, and human virus isolates. All subtypes of avian virus NAs examined and one equine virus N8 NA possessed high levels of Hemadsorption activity. A swine virus N1 NA exhibited only weak Hemadsorption activity, while in human virus N1 and N2 NAs, the activity was detected at a much lower level than in avian virus NAs. NAs which possessed Hemadsorption activity for chicken erythrocytes (RBCs) were similarly able to adsorb human RBCs. However, none of the Hemadsorption-positive NAs could bind equine, swine, or bovine RBCs, suggesting that RBCs from these species lack molecules, recognized by the NA Hemadsorption site, present on human and chicken RBCs. Mutagenesis of the putative Hemadsorption site of A/duck/Hong Kong/7/75 N2 NA abolished the high level of Hemadsorption activity exhibited by the wild-type protein but also resulted in a 50% reduction of the NA enzymatic activity. A transfectant virus, generated by reverse genetics, containing this mutated NA replicated 10-fold less efficiently in chicken embryo fibroblast cultures than did a transfectant virus expressing the wild-type NA. However, both viruses replicated equally well in Peking ducks. Although conservation of NA Hemadsorption activity among avian virus NAs suggests the maintenance of a required function of NA, loss of the activity does not preclude the replication of the virus in an avian host.
Robin Buckland - One of the best experts on this subject based on the ideXlab platform.
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identification of two amino acids in the hemagglutinin glycoprotein of measles virus mv that govern Hemadsorption hela cell fusion and cd46 downregulation phenotypic markers that differentiate vaccine and wild type mv strains
Journal of Virology, 1996Co-Authors: V Lecouturier, Joel Fayolle, M Caballero, Juan Carabana, Maria Luisa Celma, Rafael Fernandezmunoz, T F Wild, Robin BucklandAbstract:We have used site-directed mutagenesis of the hemagglutinin (H) glycoprotein of measles virus (MV) to investigate the molecular basis for the phenotypic differences observed between MV vaccine strains and recently isolated wild-type MV strains. The former downregulate CD46, the putative cellular receptor of MV, are positive for Hemadsorption, and are fusogenic in HeLa cells, whereas the latter are negative for these phenotypic markers. CD46 downregulation in particular, could have profound consequences for the immunopathology of MV infection, as this molecule protects the cell from complement lysis. Mutagenesis of two amino acids, valine and tyrosine at positions 451 and 481, respectively, in the H protein from the vaccine-like Halle MV strain to their counterparts, glutamate and asparagine, in the H protein from the wild-type Ma93F MV strain (creating the V451E/Y481N double mutation) abrogated CD46 downregulation, HeLa cell fusion, and Hemadsorption. The converse double mutagenesis of the Ma93F H protein (E451V/N481Y) transferred the CD46-downregulating, fusogenic, and Hemadsorption functions to this protein. The data provide the first mapping study of the functional domains of MV H. The consequences of these results for MV vaccine design and the role of CD46 in MV infection are discussed.
Denis Kolbasov - One of the best experts on this subject based on the ideXlab platform.
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comparative analysis of african swine fever virus genotypes and serogroups
Emerging Infectious Diseases, 2015Co-Authors: Alexander Malogolovkin, Galina Burmakina, Ilya Titov, A D Sereda, Andrey Gogin, Elena Baryshnikova, Denis KolbasovAbstract:African swine fever virus (ASFV) causes highly lethal hemorrhagic disease among pigs, and ASFV’s extreme antigenic diversity hinders vaccine development. We show that p72 ASFV phylogenetic analysis does not accurately define ASFV Hemadsorption inhibition assay serogroups. Thus, conventional ASFV genotyping cannot discriminate between viruses of different virulence or predict efficacy of a specific ASFV vaccine.
Darwyn Kobasa - One of the best experts on this subject based on the ideXlab platform.
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Neuraminidase Hemadsorption activity, conserved in avian influenza A viruses, does not influence viral replication in ducks.
Journal of virology, 1997Co-Authors: Darwyn Kobasa, M E Rodgers, Krisna Wells, Yoshihiro KawaokaAbstract:The N1 and N9 neuraminidase (NA) subtypes of influenza A viruses exhibit significant Hemadsorption activity that localizes to a site distinct from that of the enzymatic active site. To determine the conservation of Hemadsorption activity among different NAs, we have examined most of the NA subtypes from avian, swine, equine, and human virus isolates. All subtypes of avian virus NAs examined and one equine virus N8 NA possessed high levels of Hemadsorption activity. A swine virus N1 NA exhibited only weak Hemadsorption activity, while in human virus N1 and N2 NAs, the activity was detected at a much lower level than in avian virus NAs. NAs which possessed Hemadsorption activity for chicken erythrocytes (RBCs) were similarly able to adsorb human RBCs. However, none of the Hemadsorption-positive NAs could bind equine, swine, or bovine RBCs, suggesting that RBCs from these species lack molecules, recognized by the NA Hemadsorption site, present on human and chicken RBCs. Mutagenesis of the putative Hemadsorption site of A/duck/Hong Kong/7/75 N2 NA abolished the high level of Hemadsorption activity exhibited by the wild-type protein but also resulted in a 50% reduction of the NA enzymatic activity. A transfectant virus, generated by reverse genetics, containing this mutated NA replicated 10-fold less efficiently in chicken embryo fibroblast cultures than did a transfectant virus expressing the wild-type NA. However, both viruses replicated equally well in Peking ducks. Although conservation of NA Hemadsorption activity among avian virus NAs suggests the maintenance of a required function of NA, loss of the activity does not preclude the replication of the virus in an avian host.