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Aquabirnavirus

The Experts below are selected from a list of 198 Experts worldwide ranked by ideXlab platform

Kiyokuni Muroga – 1st expert on this subject based on the ideXlab platform

  • in vivo and in vitro analysis of the resistance against viral haemorrhagic septicaemia virus in japanese flounder paralichthys olivaceus precedingly infected with Aquabirnavirus
    Fish & Shellfish Immunology, 2004
    Co-Authors: Rolando Pakingking, Kiyokuni Muroga, Misao Arimoto, Kohichiro Mori, Yasushi Okinaka, Toshihiro Nakai

    Abstract:

    The resistance of Japanese flounder (Paralichthys olivaceus Temminck et Schlegel) against a viral haemorrhagic septicaemia virus (VHSV) challenge induced by a preceding non-lethal Aquabirnavirus (ABV) challenge was investigated through experimental dual-infections with different intervals between the two challenges. The non-specific protection conferred by the primary ABV infection against the secondary VHSV infection commenced at Day 3 and persisted up to Day 14 but vanished at Day 21 post-ABV challenge. The in vitro assay using HINAE (hirame natural embryo) cells demonstrated anti-VHSV activity in the serum of ABV-challenged flounder from Day 1 to Day 14 but not at Day 21 post-ABV challenge. A high expression of a Mx gene, a molecular marker of type I interferon(s) (IFN) occurred in the head kidneys of ABV-challenged flounder from Day 1 to Day 7. These results suggest that the non-specific protection against the secondary VHSV infection in flounder was due to IFN(s) induced by the primary ABV infection. � 2003 Elsevier Ltd. All rights reserved.

  • experimental coinfection with Aquabirnavirus and viral hemorrhagic septicemia virus vhsv edwardsiella tarda or streptococcus iniae in japanese flounder paralichthys olivaceus
    Fish Pathology, 2003
    Co-Authors: Rolando Pakingking, Toyohiko Nishizawa, Yoshisuke Iida, Misao Arimoto, Kohichiro Mori, Ryoko Takano, Kiyokuni Muroga

    Abstract:

    Japanese flounder Paralichthys olivaceus, farmed or wild, are ofoen infected with Aquabirnavirus (ABV) but the virus does not usually exhibit pathogenicity to the fish under usual experimental conditions. The present study investigated the experimental coinfection in flounder with ABV and three flounder pathogens, i.e. viral hemorrhagic septicemia virus (VHSV), Edwardsiella tarda and Streptococcus iniae. When young flounder were injected with ABV (106.5 TCID50/fish) and subsequently (1 week later) injected with VHSV (106.7 or 104.7 TCID50/fish), higher survival rates were obtained in these flounder compared with those in fish infected with VHSV alone. In contrast, higher mortalities occurred in the flounder dually injected with ABV (106.8 TCID50/fish) and E. tarda (1.4 × 101 CFU/fish) or S. iniae (1.7 × 102 CFU/fish) at a 1 week-interval than those in fish infected with bacteria alone. These results indicate that the primary ABV infection in flounder suppresses the secondary viral infection but facilitates the secondary bacterial infections.

  • isolation of Aquabirnavirus and viral hemorrhagic septicemia virus vhsv from wild marine fishes
    Fish Pathology, 2002
    Co-Authors: Leo Watanabe, Toyohiko Nishizawa, Rolando Pakingking, Hideki Iida, Yoshisuke Iida, Misao Arimoto, Kiyokuni Muroga

    Abstract:

    A survey of virus isolation was conducted on 160 samples of wild Japanese flounder Paralichthys olivaceus and 366 samples of other 9 wild fish species collected in 8 coastal areas of Japan in 2001. Aquabirnavirus (ABV) was isolated from flounder (15%), Japanese horse mackerel Trachurus japonicus (23%), and dark banded rockfish Sebastes inermis (4%). Viral hemorrhagic septicemia virus (VHSV) was isolated from flounder (10%) and sand lance Ammodytes personatus (2%) while the other 6 fish species were virus-negative. Concurrently, the distribution of viruses was also examined in 200 flounder collected from different hatcheries and grow-out farms. Only 1.5% of the farmed flounder were ABV-positive and none was VHSV-positive.

Toyohiko Nishizawa – 2nd expert on this subject based on the ideXlab platform

  • Establishment and characterization of the Epithelioma Papulosum Cyprini (EPC) cell line persistently infected with Infectious Pancreatic Necrosis Virus (IPNV), an Aquabirnavirus
    Journal of Microbiology, 2012
    Co-Authors: Hyung-kyu Hwang, Myungjoo Oh, Toyohiko Nishizawa

    Abstract:

    Infectious pancreatic necrosis virus (IPNV), a type species of Aquabirnaviruses in the family Birnaviridae , is an etiological agent of infectious pancreatic necrosis and has been isolated from epizootics of cultured salmonids. In the present study, an epithelioma papulosum cyprini (EPC) cell line persistently infected with IPNV (PI-EPC) was experimentally established by subculturing EPC cells surviving IPNV infection, and was characterized. PI-EPC cells were morphologically indistinguishable from EPC, but continued to grow and yield IPNV. PI-EPC cells showed no cytopathic effect due to IPNV inoculation, and susceptibility of PI-EPC cells against heterologous viruses was not different from that of EPC cells. Only one cell of 10^3.5 PI-EPC cells produced IPNV at approximately 10^0.5 50% tissue culture infectious dose (TCID50)/cell/day, which was approximately 1,000 times lower than that of normal EPC cells. PI-EPC cells that did not yield IPNV (N-PI-EPC) were screened. The IPNV genome was detected from both PI-EPC and N-PI-EPC cells, and the IPNV VP2 structural protein was detected from both cell lines, but no other IPNV proteins were observed by Western blot analysis with anti-IPNV serum. Thus, multiplication of IPNV in PI-EPC cells was regulated by some host cell factors, except interferon.

  • An approach for genogrouping of Japanese isolates of Aquabirnaviruses in a new genogroup, VII, based on the VP2/NS junction region
    Journal of General Virology, 2005
    Co-Authors: Toyohiko Nishizawa, Shinichi Kinoshita, Mamoru Yoshimizu

    Abstract:

    Aquabirnaviruses, represented by Infectious pancreatic necrosis virus (IPNV), have been isolated from epizootics in salmonids and a variety of aquatic animals in the world; six genogroups of Aquabirnaviruses have been identified. In comparisons of nucleotide sequences of the VP2/NS junction region, maximum nucleotide diversities of 30·8 % were observed among 93 worldwide Aquabirnavirus isolates. A phylogenetic tree revealed the existence of a new genogroup, VII, for Japanese Aquabirnavirus isolates from marine fish and molluscan shellfish. Nucleotide diversities between genogroups VII and I–VI were 18·7 % or greater. At the nucleotide level, Japanese IPNV isolates from epizootics in salmonids were nearly identical to a genogroup I strain from the USA or Canada. It is suggested that Japanese IPNV isolates belonging to genogroup I were originally introduced from North American sources, whereas Japanese Aquabirnavirus isolates of genogroup VII were from marine aquatic animals indigenous to Japan.

  • experimental coinfection with Aquabirnavirus and viral hemorrhagic septicemia virus vhsv edwardsiella tarda or streptococcus iniae in japanese flounder paralichthys olivaceus
    Fish Pathology, 2003
    Co-Authors: Rolando Pakingking, Toyohiko Nishizawa, Yoshisuke Iida, Misao Arimoto, Kohichiro Mori, Ryoko Takano, Kiyokuni Muroga

    Abstract:

    Japanese flounder Paralichthys olivaceus, farmed or wild, are ofoen infected with Aquabirnavirus (ABV) but the virus does not usually exhibit pathogenicity to the fish under usual experimental conditions. The present study investigated the experimental coinfection in flounder with ABV and three flounder pathogens, i.e. viral hemorrhagic septicemia virus (VHSV), Edwardsiella tarda and Streptococcus iniae. When young flounder were injected with ABV (106.5 TCID50/fish) and subsequently (1 week later) injected with VHSV (106.7 or 104.7 TCID50/fish), higher survival rates were obtained in these flounder compared with those in fish infected with VHSV alone. In contrast, higher mortalities occurred in the flounder dually injected with ABV (106.8 TCID50/fish) and E. tarda (1.4 × 101 CFU/fish) or S. iniae (1.7 × 102 CFU/fish) at a 1 week-interval than those in fish infected with bacteria alone. These results indicate that the primary ABV infection in flounder suppresses the secondary viral infection but facilitates the secondary bacterial infections.

Mark Paetzel – 3rd expert on this subject based on the ideXlab platform

  • Crystal Structures of Yellowtail Ascites Virus VP4 Protease TRAPPING AN INTERNAL CLEAVAGE SITE TRANS ACYL-ENZYME COMPLEX IN A NATIVE SER/LYS DYAD ACTIVE SITE
    Journal of Biological Chemistry, 2013
    Co-Authors: Ivy Yeuk Wah Chung, Mark Paetzel

    Abstract:

    Yellowtail ascites virus (YAV) is an Aquabirnavirus that causes ascites in yellowtail, a fish often used in sushi. Segment A of the YAV genome codes for a polyprotein (pVP2-VP4-VP3), where processing by its own VP4 protease yields the capsid protein precursor pVP2, the ribonucleoprotein-forming VP3, and free VP4. VP4 protease utilizes the rarely observed serine-lysine catalytic dyad mechanism. Here we have confirmed the existence of an internal cleavage site, preceding the VP4/VP3 cleavage site. The resulting C-terminally truncated enzyme (ending at Ala716) is active, as shown by a trans full-length VP4 cleavage assay and a fluorometric peptide cleavage assay. We present a crystal structure of a native active site YAV VP4 with the internal cleavage site trapped as trans product complexes and trans acyl-enzyme complexes. The acyl-enzyme complexes confirm directly the role of Ser633 as the nucleophile. A crystal structure of the lysine general base mutant (K674A) reveals the acyl-enzyme and empty binding site states of VP4, which allows for the observation of structural changes upon substrate or product binding. These snapshots of three different stages in the VP4 protease reaction mechanism will aid in the design of anti-birnavirus compounds, provide insight into previous site-directed mutagenesis results, and contribute to understanding of the serine-lysine dyad protease mechanism. In addition, we have discovered that this protease contains a channel that leads from the enzyme surface (adjacent to the substrate binding groove) to the active site and the deacylating water.

  • Crystal Structure of a Viral Protease Intramolecular Acyl-enzyme Complex: INSIGHTS INTO cis-CLEAVAGE AT THE VP4/VP3 JUNCTION OF TELLINA BIRNAVIRUS*
    Journal of Biological Chemistry, 2011
    Co-Authors: Ivy Chung, Mark Paetzel

    Abstract:

    Viruses of the Birnaviridae family are characterized by their bisegmented double-stranded RNA genome that resides within a single-shelled non-enveloped icosahedral particle. They infect birds, aquatic organisms, and insects. Tellina virus 1 (TV-1) is an Aquabirnavirus isolated from the mollusk Tellina tenuis. It encodes a polyprotein (NH2-pVP2-X-VP4-VP3-COOH) that is cleaved by the self-encoded protease VP4 to yield capsid precursor protein pVP2, peptide X, and ribonucleoprotein VP3. Here we report the crystal structure of an intramolecular (cis) acyl-enzyme complex of TV-1 VP4 at 2.1-Å resolution. The structure reveals how the enzyme can recognize its own carboxyl terminus during the VP4/VP3 cleavage event. The methyl side chains of Ala830(P1) and Ala828(P3) at the VP4/VP3 junction point into complementary shallow and hydrophobic S1 and S3 binding pockets adjacent to the VP4 catalytic residues: nucleophile Ser738 and general base Lys777. The electron density clearly shows that the carbonyl carbon of Ala830 is covalently attached via an ester bond to the Oγ of Ser738. A highly ordered water molecule in the active site is coordinated in the proper position to act as the deacylating water. A comparative analysis of this intramolecular (cis) acyl-enzyme structure with the previously solved intermolecular (trans) acyl-enzyme structure of infectious pancreatic necrosis virus VP4 explains the narrower specificity observed in the cleavage sites of TV-1 VP4.

  • Crystal Structure of a Viral Protease Intramolecular Acyl-enzyme Complex
    , 2011
    Co-Authors: Ivy Yeuk, Wah Chung, Mark Paetzel

    Abstract:

    Viruses of the Birnaviridae family are characterized by their bisegmented double-stranded RNA genome that resides within a single-shelled non-enveloped icosahedral particle. They infect birds, aquatic organisms, and insects. Tellina virus 1 (TV-1) is an Aquabirnavirus isolated from the mollusk Tellina tenuis .I t encodes a polyprotein (NH2-pVP2-X-VP4-VP3-COOH) that is cleaved by the self-encoded protease VP4 to yield capsid precursor protein pVP2, peptide X, and ribonucleoprotein VP3. Here we report the crystal structure of an intramolecular (cis) acyl