Publications by authors named "Mamoru Yoshimizu"

The aims of this research were to perform molecular characterization and biofunctional analyses of giant river prawn and genes ( and ) under various stress conditions. Comparisons of the nucleotide and amino acid sequences of and with those of other species showed the highest similarity scores with crustaceans. Under normal conditions, expression analysis using quantitative real-time RT-PCR (qRT-PCR) indicated that was highly expressed in the gills and testis, and expression was observed in all tissues, with the highest expression in the ovary.

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Drosophila Mos1 belongs to the mariner family of transposons, which are one of the most ubiquitous transposons among eukaryotes. We first determined nuclear transportation of the Drosophila Mos1-EGFP fusion protein in fish cell lines because it is required for a function of transposons. We next constructed recombinant baculoviral vectors harboring the Drosophila Mos1 transposon or marker genes located between Mos1 inverted repeats.

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In immunization of fish with polyinosinic-polycytidylic acid (poly[I:C], a synthetic double-stranded RNA, injection of Poly(I:C) followed by challenge with a live virus induces a transient, non-specific antiviral state by interferon activity. When exposed to a virus while in this antiviral state, the fish acquire a specific and protective immunity against the corresponding viral disease and survive. In the present study, the effiacy of Poly(I:C) immunization was investigated in japanese flounder Paralichthys olivaceus using viral hemorrhagic septicemia virus (VHSV) as a model; the minimum dose of Poly(I:C) required for inducing protection and the duration of the antiviral state were determined, and a potentially curative effect of Poly(I:C) administration was assessed.

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Viral nervous necrosis (VNN), caused by a fish nodavirus, is one of the most serious fish diseases worldwide. Here we report a unique vaccination method in sevenband grouper Epinephelus septemfasciatus using a synthetic double-stranded RNA polyinosinic polycytidylic acid (Poly(I:C)), an interferon inducer, followed by challenge with a live fish nodavirus. Fish injected with Poly(I:C) at 200 microg fish(-1) were highly protected from artificial challenge with red-spotted grouper nervous necrosis virus (RGNNV) (relative percentage survival, RPS: 100%), and specific antibodies against RGNNV were detected in sera from survivors.

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It was recently reported that prophylaxis against infectious hematopoietic necrosis virus (IHNV) in fish was induced by pre-exposure to the infectious pancreatic necrosis virus (IPNV). Here the establishment of IHNV immunity in rainbow trout Oncorhynchus mykiss was investigated by IHNV challenge following non-lethal pre-infection with IPNV. Also, synthetic double-stranded RNA polyinosinic polycytidylic acid, Poly(I:C), an inducer for interferon (IFN), was evaluated as a substitute for IPNV induction of the non-specific antiviral state and subsequent IHNV-specific immunity in fish.

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White spot syndrome virus (WSSV) is the causative agent of white spot disease (WSD), one of the most serious diseases affecting global shrimp farming. We compared WSSV infection induction in kuruma shrimp Marsupenaeus japonicus by oral, immersion, and intramuscular injection (IM) exposure methods and evaluated the oral vaccine prepared from the recombinant WSSV proteins rVP26 and rVP28. The 50% lethal doses (LD50) of WSSV by oral, immersion, and IM challenges were 10(-0.

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Mitogen-activated protein kinases (MAPKs) are a family of Ser/Thr protein kinases that transmit various extracellular signals to the nucleus inducing gene expression, cell proliferation, and apoptosis. Recent studies have revealed that organotin compounds induce apoptosis and MAPK phosphorylation/activation in mammal cells. In this study, we elucidated the cytotoxic mechanism of tributyltin (TBT), a representative organotin compound, in rainbow trout (Oncorhynchus mykiss) RTG-2 cells.

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TLR22 occurs exclusively in aquatic animals and its role is unknown. Herein we show that the fugu (Takifugu rubripes) (fg)TLR3 and fgTLR22 link the IFN-inducing pathway via the fg Toll-IL-1R homology domain-containing adaptor protein 1(fgTICAM-1, or TRIF) adaptor in fish cells. fgTLR3 resides in endoplasmic reticulum and recognizes relatively short-sized dsRNA, whereas fgTLR22 recognizes long-sized dsRNA on the cell surface.

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Fish nodaviruses are causative agents of viral nervous necrosis causing high mortality in cultured marine fishes around the world. The first successful isolation of fish nodavirus was made with SSN-1 cells, which are persistently infected with snakehead retrovirus (SnRV). In the present study, a BF-2 cell line persistently infected with SnRV (PI-BF-2) was established to evaluate the influence of SnRV on the production of fish nodavirus.

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Viral hemorrhagic septicemia (VHS) is one of the most serious fish viral diseases for cultured rainbow trout (Oncorhynchus mykiss), although VHS virus (VHSV) seems to be ubiquitous among marine fishes. In the present study, VHSV isolation was performed with free-living and cultured turbot (Psetta maxima) in the Trabzon coastal area of the Black Sea to evaluate participation of VHSV in mass mortalities of seed-produced turbot larvae. VHSV was detected in 14 of 66 free-living spawners (positive ratio, 21.

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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.

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When analyzed by fluorescent amplified fragment length polymorphism and repetitive extragenic palindrome-PCR fingerprinting, a total of 47 Vibrio halioticoli strains isolated from four Japanese abalone species and one turban shell species formed three clusters that roughly reflect the different species of host abalone from which they were isolated. The V. halioticoli isolates from turban shells were distributed evenly among the clusters.

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Adsorption of infectious hematopoietic necrosis virus (IHNV) to sea sand, Japanese acid clay, diatomaceous earth, kaolin, bentonite, quartz sand, chitin, cellulose powder, ion exchange hydrophobic Toyopeal and Cellulofine, alundum, active carbon, silica gel, glass, plastic, and bacterial cells was studied. The IHNV adsorbed to several clays (kaolin, bentonite, Japanese acid clay) and diatomaceous earth in sterilized water with a wide range of pH (5-11) at concentrations of 1, 10, and 100 mg/mL. Except for bentonite, infectivity of clay-adsorbed IHNV persisted for as long as 9 weeks.

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Viruses causing infectious pancreatic necrosis (IPN) and infectious hematopoietic necrosis (IHN) were first isolated in Japan during the 1970s and these two diseases remain among the most serious problems affecting cultured salmonids in Japan. In addition to IHN and IPN, four other viral diseases cause major economic losses among cultured fishes in Japan. These include viral pancreatic hepatic necrosis of yellowtail, rhabdovirus infection of Japanese flounder and black rock fish, Kuchishiro-sho of tiger puffer fish, and epidermal hyperplasia or necrosis of Japanese flounder.

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