The Experts below are selected from a list of 168 Experts worldwide ranked by ideXlab platform

Juan Kuznar - One of the best experts on this subject based on the ideXlab platform.

  • Visualization of Infectious Pancreatic Necrosis virus (IPNV) particles labeled with fluorescent probes.
    Journal of virological methods, 2005
    Co-Authors: Manuel Osorio, J. C. Espinoza, Juan Kuznar
    Abstract:

    Infectious Pancreatic Necrosis virus (IPNV) particles were labeled with SYBR Green I or a monoclonal antibody and FITC-conjugated secondary antibody and examined in a fluorescence microscope. Labeled viral particles were visualized in a narrow range of pixels. Comparing IPNV particles with fluorescent phage T4 virions, the former, as expected, were seen smaller in size. The method allows the rapid and accurate counting of viral particles both on filters and bound to the cell surface. In addition, IPNV particles can be specifically enumerated in the presence of other virions and the ratio between physical particles and virus infectivity can be easily calculated as well.

  • Rapid simultaneous detection and quantitation of Infectious Pancreatic Necrosis virus (IPNV).
    Journal of virological methods, 2002
    Co-Authors: J. C. Espinoza, Juan Kuznar
    Abstract:

    Infectious Pancreatic Necrosis virus (IPNV) is a pathogen of great concern in the salmon industry as well as in the environment. Taking advantage of the early immunofluorescent visualization of viral proteins in infected cells, a titration method was developed. At 16 h p.i., fluorescent foci were visualized with a monoclonal antibody against VP3-structural protein of the virus. The counting of each fluorescent cell allows the quantitation of infection foci; titres expressed in fluorescent foci/ml were equivalent to plaque forming units (PFU)/ml. With slight modifications, the same method used to detect the virus in field samples, can be applied to estimate virus contents. Some of the samples used during the assays were obtained from routine screening procedures. The titres recorded from positive samples correlated well with the clinical condition of the fish. With this method, rapid diagnosis and quantitation may simultaneously be performed with the same tissue extract.

  • Infectious Pancreatic Necrosis virus (IPNV) enumeration through epifluorescence microscopy: technical aspects
    Electronic Journal of Biotechnology, 2001
    Co-Authors: Maria Soledad Pavlov, J. C. Espinoza, Yoanna Eissler, David E. Garland, Juan Kuznar
    Abstract:

    A method for counting Infectious Pancreatic Necrosis Virus (IPNV) through epifluorescence microscopy was analyzed in detail. Image processing and statistic considerations are included. The particle size of viruses was compared in different experimental conditions such as the staining of the virus with SYBR-Green I or with antibodies for specific fluorescence labeling of viral proteins. The type of surface used as mounting support was assayed as well. The results indicated that the most suitable method involves the mounting of the viral-containing suspension on a membrane filter followed by the staining with a monoclonal antibody specific for a viral protein combined with a FITC (fluorescein isothiocyanate)-conjugated secondary antibody.

  • Temporal and subcellular localization of Infectious Pancreatic Necrosis virus structural proteins.
    Archives of virology, 2000
    Co-Authors: J. C. Espinoza, A. Hjalmarsson, Einar Everitt, Juan Kuznar
    Abstract:

    The temporal subcellular localization of the structural proteins VP2 and VP3 of Infectious Pancreatic Necrosis virus was analyzed with monoclonal antibodies conjugated with fluorochromes. Early in the infection both proteins were colocalized in the cytosol, at later times, VP2 was visualized as inclusion bodies around the nuclei of the cells and, sometimes, it was found in elongated tubular structures that might correspond to the type I tubules seen in cells infected with another Birnavirus. As VP2 is a glycosylated protein we determined its subcellular localization compared with that of ER and Golgi probes. These results suggest that VP2 is glycosylated freely in the cytoplasm.

  • Infectious Pancreatic Necrosis virus (IPNV) does not requireacid compartments for entry into cells
    Archives of virology, 1997
    Co-Authors: J. C. Espinoza, Juan Kuznar
    Abstract:

    The early events in the infection of unenveloped viruses are still rather unknown and puzzling. However, as in the case of enveloped viruses, the acid pH of endosomes can be important to trigger the virus entry into the cytosol. To test if the Infectious Pancreatic Necrosis virus (IPNV), an unenveloped virus, requires acid endosomal pH to infect cells, we assayed the effect of Bafilomycin Aff1 on IPNV replication. Concentrations of the antibiotic which inhibited the endosomal acidification of the host cells were unable to affect IPNV replication in CHSE-214 cells; therefore, the acid pH of endosomes seems not to be a mandatory condition for the entry of IPNV into cells.

Peter Dobos - One of the best experts on this subject based on the ideXlab platform.

  • Mapping of a Serotype Specific Epitope of the Major Capsid Protein VP2 of Infectious Pancreatic Necrosis Virus
    Virology, 1995
    Co-Authors: Linda Liao, Peter Dobos
    Abstract:

    A serotype-specific, conformational epitope of VP2 of Infectious Pancreatic Necrosis virus (IPNV) (Jasper), has been mapped by restriction enzyme site-specific deletions of cloned viral cDNA. Subclones encoding fragments of VP2 were expressed in Escherichia coli followed by polyacrylamide gel electrophoresis and Western blot analysis. The epitope (between amino acid residues 242 and 325) reacted with monoclonal anti-VP2 antibodies that neutralized the homologous (Jasper), but not the heterologous (Sp) serotype of IPNV.

  • In vitro guanylylation of Infectious Pancreatic Necrosis virus polypeptide VP1
    Virology, 1993
    Co-Authors: Peter Dobos
    Abstract:

    Abstract Incubation of purified Infectious Pancreatic Necrosis virus (IPNV) in the presence of [α 32 P]GTP resulted in the formation of VP1-GMP. The GMP is linked to VP1 by a phosphodiester bond and its formation does not require the presence of divalent cations. In contrast to reovirus guanylyl transferase, the formation of IPNV VP1-GMP is not reversible and the guanylylation reaction is not inhibited by inorganic pyrophosphate. Furthermore, the IPNV VP1-GMP cannot transfer the GMP to an acceptor molecule (such as GTP) indicating that VP1 is not a capping enzyme. Time-coarse experiments revealed that after the initial guanylylation of VP1 to form VP1-pG, a second GMP is added to form VP1 -pGpG, the formation of which is template-dependent. Since VP1 is present in the virion both as a free polypeptide and in a genome-linked form as VPg, and it is also the virion-associated RNA polymerase, the results suggest that VP1 may function as a primer during in vitro RNA synthesis.

  • Antigenic and genomic differences of two Jasper strains of Infectious Pancreatic Necrosis virus.
    Intervirology, 1992
    Co-Authors: Laurent Berthiaume, Esther Tarrab, Maximilien Arella, Peter Dobos, Joël Heppell, Roy Duncan, Jacqueline Lecomte
    Abstract:

    Strains of Infectious Pancreatic Necrosis virus (IPNV-Jasper) obtained from two different laboratories were compared serologically with polyclonal and monoclonal antibodies. Nucleotide sequence and restriction endonuclease patterns of 359-bp fragment of genome segment A cDNA were also compared. Substantial differences were found in both analyses that will support the fact that the two Jasper strains are not identical.

  • Characterization of the VPg-dsRNA linkage of Infectious Pancreatic Necrosis virus.
    Journal of General Virology, 1991
    Co-Authors: Jay G. Calvert, Maritza Soler, Éva Nagy, Peter Dobos
    Abstract:

    By the use of strong denaturing agents, a genome-linked protein (VPg)-RNA complex was purified from Infectious Pancreatic Necrosis virus. Ribonuclease treatment of 125I-labelled VPg-RNA released a 90K polypeptide identical to the minor structural polypeptide VP1 (the putative RNA polymerase), as determined by peptide mapping. The polypeptide is linked to the RNA by a serine-5′ GMP phosphodiester bond. The results identify birnaviruses as the only dsRNA viruses with a VPg, the size of which is the largest of the VPgs of RNA viruses.

Alexander G Murray - One of the best experts on this subject based on the ideXlab platform.

  • Persistence of Infectious Pancreatic Necrosis virus (IPNV) in Scottish salmon (Salmo salar L.) farms.
    Preventive veterinary medicine, 2006
    Co-Authors: Alexander G Murray
    Abstract:

    Infectious Pancreatic Necrosis is a disease that is causing increasing loses to Scottish Atlantic-salmon farms. I asked the question: is infection of individual salmon farms persistent or transient? Using Fisheries Research Services' Fish Health Inspectors' data, conditional probabilities that a farm would (time 0) be infected were estimated for farms that had been infected [P(I(0)|I(-T))] or free [P(I(0)|F(-T))] from Infectious Pancreatic Necrosis virus (IPNV) when a sample was taken at some earlier time (-T). A logistic-regression model was used to estimate these conditional probabilities with T; this model was multilevel to account for regional and inter-annual level differences in prevalence of IPNV. In freshwater, conditional probabilities remained substantially different for periods of at least 4 years, so, although many farms did change infection status, IPNV either persisted or recurred at specific freshwater farms. Marine farms showed similar conditional probabilities after about 2 years following a positive or a negative sample, indicating that infection was transient. Management of larger areas and exchanges between farms might be more effective than farm-level management at controlling marine IPNV.

  • Infectious Pancreatic Necrosis virus in scottish atlantic salmon farms 1996 2001
    Emerging Infectious Diseases, 2003
    Co-Authors: Alexander G Murray, Corina D Busby, David W Bruno
    Abstract:

    The rapid growth of aquaculture has provided opportunities for the emergence of diseases. Programs designed to monitor these pathogens are useful for analysis of regional variation and trends, provided methods are standardized. Data from an official monitoring program were used to analyze the emergence of Infectious Pancreatic Necrosis virus in Scottish salmon farms from 1996 to 2001. An annual increase in the prevalence of this virus was found in saltwater (10%) and freshwater sites (2% to 3%), with a much faster increase (6.5%) in Shetland’s freshwater sites. No significant increase in the virus was detected in the marine farms of southern mainland Scotland. However, the virus had become very prevalent at marine sites and was almost ubiquitous in Shetland by 2001, and thus the prevalence of this virus at marine sites may be underestimated. Because several diseases have emerged or are emerging in fish farming, aquaculture surveillance programs represent a rich potential source of data on emerging diseases.

J. C. Espinoza - One of the best experts on this subject based on the ideXlab platform.

  • Visualization of Infectious Pancreatic Necrosis virus (IPNV) particles labeled with fluorescent probes.
    Journal of virological methods, 2005
    Co-Authors: Manuel Osorio, J. C. Espinoza, Juan Kuznar
    Abstract:

    Infectious Pancreatic Necrosis virus (IPNV) particles were labeled with SYBR Green I or a monoclonal antibody and FITC-conjugated secondary antibody and examined in a fluorescence microscope. Labeled viral particles were visualized in a narrow range of pixels. Comparing IPNV particles with fluorescent phage T4 virions, the former, as expected, were seen smaller in size. The method allows the rapid and accurate counting of viral particles both on filters and bound to the cell surface. In addition, IPNV particles can be specifically enumerated in the presence of other virions and the ratio between physical particles and virus infectivity can be easily calculated as well.

  • Rapid simultaneous detection and quantitation of Infectious Pancreatic Necrosis virus (IPNV).
    Journal of virological methods, 2002
    Co-Authors: J. C. Espinoza, Juan Kuznar
    Abstract:

    Infectious Pancreatic Necrosis virus (IPNV) is a pathogen of great concern in the salmon industry as well as in the environment. Taking advantage of the early immunofluorescent visualization of viral proteins in infected cells, a titration method was developed. At 16 h p.i., fluorescent foci were visualized with a monoclonal antibody against VP3-structural protein of the virus. The counting of each fluorescent cell allows the quantitation of infection foci; titres expressed in fluorescent foci/ml were equivalent to plaque forming units (PFU)/ml. With slight modifications, the same method used to detect the virus in field samples, can be applied to estimate virus contents. Some of the samples used during the assays were obtained from routine screening procedures. The titres recorded from positive samples correlated well with the clinical condition of the fish. With this method, rapid diagnosis and quantitation may simultaneously be performed with the same tissue extract.

  • Infectious Pancreatic Necrosis virus (IPNV) enumeration through epifluorescence microscopy: technical aspects
    Electronic Journal of Biotechnology, 2001
    Co-Authors: Maria Soledad Pavlov, J. C. Espinoza, Yoanna Eissler, David E. Garland, Juan Kuznar
    Abstract:

    A method for counting Infectious Pancreatic Necrosis Virus (IPNV) through epifluorescence microscopy was analyzed in detail. Image processing and statistic considerations are included. The particle size of viruses was compared in different experimental conditions such as the staining of the virus with SYBR-Green I or with antibodies for specific fluorescence labeling of viral proteins. The type of surface used as mounting support was assayed as well. The results indicated that the most suitable method involves the mounting of the viral-containing suspension on a membrane filter followed by the staining with a monoclonal antibody specific for a viral protein combined with a FITC (fluorescein isothiocyanate)-conjugated secondary antibody.

  • Attachment and entry of Infectious Pancreatic Necrosis virus (IPNV) into CHSE-214 cells
    Archives of virology, 1995
    Co-Authors: Juan Kuznar, Gilda Farías, Maritza Soler, J. C. Espinoza
    Abstract:

    Infectious Pancreatic Necrosis virus (IPNV) attaches to CHSE-214 cells through two types of cell components: specific and non-specific ones. Competition experiments with inactivated IPNV showed that IPNV requires specific components to productively infect cells. Just a low amount of adsorbed IPNV enters the cell. After 20 minutes, part of the adsorbed IPNV was internalized into acid compartments. Also, the viruses adsorbed on the cell surface require similar periods of time to escape from the neutralization of antibodies.

J. C. Espinoza - One of the best experts on this subject based on the ideXlab platform.

  • Temporal and subcellular localization of Infectious Pancreatic Necrosis virus structural proteins.
    Archives of virology, 2000
    Co-Authors: J. C. Espinoza, A. Hjalmarsson, Einar Everitt, Juan Kuznar
    Abstract:

    The temporal subcellular localization of the structural proteins VP2 and VP3 of Infectious Pancreatic Necrosis virus was analyzed with monoclonal antibodies conjugated with fluorochromes. Early in the infection both proteins were colocalized in the cytosol, at later times, VP2 was visualized as inclusion bodies around the nuclei of the cells and, sometimes, it was found in elongated tubular structures that might correspond to the type I tubules seen in cells infected with another Birnavirus. As VP2 is a glycosylated protein we determined its subcellular localization compared with that of ER and Golgi probes. These results suggest that VP2 is glycosylated freely in the cytoplasm.

  • Infectious Pancreatic Necrosis virus (IPNV) does not requireacid compartments for entry into cells
    Archives of virology, 1997
    Co-Authors: J. C. Espinoza, Juan Kuznar
    Abstract:

    The early events in the infection of unenveloped viruses are still rather unknown and puzzling. However, as in the case of enveloped viruses, the acid pH of endosomes can be important to trigger the virus entry into the cytosol. To test if the Infectious Pancreatic Necrosis virus (IPNV), an unenveloped virus, requires acid endosomal pH to infect cells, we assayed the effect of Bafilomycin Aff1 on IPNV replication. Concentrations of the antibiotic which inhibited the endosomal acidification of the host cells were unable to affect IPNV replication in CHSE-214 cells; therefore, the acid pH of endosomes seems not to be a mandatory condition for the entry of IPNV into cells.