Fish Pathology
Online ISSN : 1881-7335
Print ISSN : 0388-788X
ISSN-L : 0388-788X
Volume 30 , Issue 2
Showing 1-14 articles out of 14 articles from the selected issue
  • M. L. Kent, D. J. Whitaker, M. J. Higgins, J. M. Blackburn, S. C. Dawe
    1995 Volume 30 Issue 2 Pages 93-99
    Published: June 15, 1995
    Released: October 26, 2009
    JOURNALS FREE ACCESS
    For 4 consecutive years, the prevalence and severity of proliferative kidney disease (PKD), caused by the PKX myxosporean, in chinook salmon (Oncorhynchus tshawytscha) from the Puntledge River Hatchery, Vancouver Island, British Columbia, Canada was investigated after the fish were transferred to sea water. In the spring of 1991 through 1994, smolts were transferred from the hatchery to the Pacific Biological Station (PBS), Nanaimo, British Columbia at about the same time that their cohorts were released for seaward migration. In 1991, fish were maintained in PKX-free fresh water, and in 1992 fish were maintained in a seawater neetpen. In 1993 and 1994 fish were maintained in seawater tanks maintained at 15-17°C. In all years, virtually all the fish were subclinically infected with PKX at the time of transfer from the hatchery, and a prevalence of almost 100% was eventually observed in the fish after they were transferred to PBS. This study demonstrates that PKD can occur in sea water in post smolts originating from watersheds where the PKX parasite is present. It is, therefore, possible that PKD may impact ocean survival of salmon originating from PKX enzootic watershed, particularly because the disease causes osmoregulatory imbalances and anemia.
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  • Kei Yuasa, Kishio Hatai
    1995 Volume 30 Issue 2 Pages 101-106
    Published: June 15, 1995
    Released: October 26, 2009
    JOURNALS FREE ACCESS
    Twenty-four isolates of Saprolegnia were obtained from fish farms, and the relationship between pathogenicity to rainbow trout (Oncorhynchus mykiss) and their biological characteristics was studied. Fifteen isolates identified as Saprolegnia parasitica were classified into three groups (Groups 1, 2 and 3) according to the mortalities following artificial infection. The isolates belonging to Group 1 which showed high pathogenicity to rainbow trout produced many characteristically catenulated gemmae, but the isolates of the other groups did not. Sensitivity to cycloheximide of the isolates of Groups 1 and 2 was higher than that of Group 3. Nine isolates identified as S. diclina were demonstrated to be saprophytic. Sensitivity of S. diclina to polyphenon- 100R was lower than that of S. parasitica. These results suggest that Saprolegnia parasitica and S. diclina can be practically distinguished by the pathogenicity to fish and some biological tests.
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  • Atsushi Yamamoto, Takaji Iida
    1995 Volume 30 Issue 2 Pages 107-110
    Published: June 15, 1995
    Released: October 26, 2009
    JOURNALS FREE ACCESS
    Triploid rainbow trout Oncorhynchus mykiss were compared with diploid trout in complement activity monitored by hemolytic and bactericidal activities, and in neutrophil activity by visual phagocytosis and luminol-dependent chemiluminescence.
    No significant differences were detected in complement activity and neutrophil activity between diploid and triploid trout. These results indicate that non-specific defense activities of triploid trout are similar to those of diploid trout, and that the triploidy does not fundamentally affect the susceptibility of the fish to diseases.
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  • Toyohiko Nishizawa, Masaaki Kise, Toshihiro Nakai, Kiyokuni Muroga
    1995 Volume 30 Issue 2 Pages 111-114
    Published: June 15, 1995
    Released: October 26, 2009
    JOURNALS FREE ACCESS
    Viral nervous necrosis (VNN) caused by a nodavirus (striped jack nervous necrosis virus : SJNNV) is a serious problem in seed production process of striped jack Pseudocaranx dentex in Japan. Mouse monoclonal antibodies (MAbs) to SJNNV were produced by using a homogenate of infected larval striped jack. Among 8 MAbs reacting with the homogenate of infected larvae in enzyme-linked immunosorbent assay (ELISA), three MAbs (SJ-102B, SJ-204D, SJ-207C) were proved to recognize the 42 kDa coat protein of SJNNV by Western blot analysis. An in vivo neutralization test, where larval striped jack were exposed to purified SJNNV (100ng/ml) or the virus treated with MAbs (1mg) and the resultant infection with SJNNV in larvae was monitored by ELISA using an anti-SJNNV rabbit serum, exhibited that two MAbs SJ-102B and SJ-204D have neutralizing activity against SJNNV.
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  • Kazuhiro Nakajima, Yukio Maeno, Mikio Fukudome, Yutaka Fukuda, Shinji ...
    1995 Volume 30 Issue 2 Pages 115-119
    Published: June 15, 1995
    Released: October 26, 2009
    JOURNALS FREE ACCESS
    By using indirect immunofluorescence (IF) test with a monoclonal antibody (MAb) against red sea bream iridovirus (RSIV), the detection method of the RSIV specific antigen was examined from imprints or frozen sections of spleens of artificially infected red sea bream Pagrus major. Immunofluorescence-positive cells were not detected from uninfected fish and those of day 1 and 3 post infection. However, a few IF-positive cells were detected from day 5 post infection and many IF-positive cells including typically enlarged cells were detected from moribund or dead fish. This method was applied to 11 species of cultured marine fishes that showed disease condition or suspected iridovirus infection. The IF-positive cells were detected from all these naturally infected fishes of 11 species. The detection rate of infected fish by IF test using MAb was much higher than that by the currently used Giemsa staining method. The results indicate that the IF test using the RSIV specific MAb is a rapid and effective method for confirmative diagnosis of the iridovirus infection in cultured marine fishes.
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  • Riichi Kusuda, Naoya Dohata, Yutaka Fukuda, Kenji Kawai
    1995 Volume 30 Issue 2 Pages 121-122
    Published: June 15, 1995
    Released: October 26, 2009
    JOURNALS FREE ACCESS
  • Atsushi Yamamoto, Takaji Iida
    1995 Volume 30 Issue 2 Pages 123-124
    Published: June 15, 1995
    Released: October 26, 2009
    JOURNALS FREE ACCESS
    The sera of all-female triploid rainbow trout Oncorhynchus mykiss were compared with those of diploids in bactericidal activity against Escherichia coli from April to December. The bactericidal activity of the diploid sera showed a marked decrease during their maturation and spawning period. The sera of triploids, however, kept high bactericidal activity through the experimental period.
    These results were supposedly due to the reproductive sterility of female triploids and might explain the fact that triploids showed better survival than diploids during reproductive period.
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  • Shinpei Wada, Kazuyo Nakamura, Kishio Hatai
    1995 Volume 30 Issue 2 Pages 125-126
    Published: June 15, 1995
    Released: October 26, 2009
    JOURNALS FREE ACCESS
  • Hisao Kamiya
    1995 Volume 30 Issue 2 Pages 129-139
    Published: June 15, 1995
    Released: October 26, 2009
    JOURNALS FREE ACCESS
    Naturaly occurring humoral lectins have been reported from wide range of animals, both invertebrates and vertebrates. In the case of invertebrate lectins, it has been postulated repeatedly that one of their biological functions is the recognition of self and nonself. Lectins may agglutinate and immobilize microbial or metazoan parasites. Furthermore, the immobilization could mediate subsequent phagocytosis or encapsulation of the parasite.
    Humoral lectins of certain invertebrates, such as the giant clam Tridacna maxima and the acorn barnacle Megabalanus rosa, have been reported as the main constituents of hemolymph proteins. In addition, the content of the humoral lectins in M. rosa showed a seasonal variation. It is not readily acceptable from these experimental observations that in these invertebrates humoral lectins participate only in the recognition-function. M. rosa lectins have been recently demonstrated to show the inhibitory activity on the growth of calcium carbonate crystal. Possible multiple-functions of the humoral lectins in M. rosa are discussed especially in connection with the calcification.
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  • Yukinori Takahashi, Toshiaki Itami, Masakazu Kondo
    1995 Volume 30 Issue 2 Pages 141-150
    Published: June 15, 1995
    Released: October 26, 2009
    JOURNALS FREE ACCESS
    The defense system of crustaceans mainly consists of two parts : cellular defense system and humoral defense system. Hemocytes and resident phagocytes are well known as cellular defense factors which have a high phagocytic activity. Nodulation and encapsulation are also reported as a celluler defense phenomenon. Factors concerning the humoral defense system include phenoloxidase (PO), the prophenoloxidase (proPO) activating system, bactericidin and lectins.
    These defense factors in the cellular and humoral systems cooperatively provide a defense barrier against invading pathogenic organisms from the environment. These systems have a mutual interaction and construct an elaborate network of host immunodefense system. However under aquaculture condition, various stresses caused by high stocking density and resultant environmental pollution with organic matter damage the host defense system resulting in an increased susceptibility to infection.
    In an attempt to prevent bacterial infection in crustacea, vaccination trials have been carried out successfully in shrimp, lobster and crayfish. Oral administration of immunopotentiators, such as β-1, 3-glucan and peptidoglycan, to shrimp increased the phagocytic activity of hemocytes and resistance against bacterial infection.
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  • Tomoki Yano
    1995 Volume 30 Issue 2 Pages 151-158
    Published: June 15, 1995
    Released: October 26, 2009
    JOURNALS FREE ACCESS
    The mammalian complement system consists of about 30 distinct proteins and is activated through the classical pathway (CCP) or the alternative pathway (ACP). The biological importance of this system has stimulated many scientists to study the complement system of fish. It has been reported that jawless fish (hagfish and lamprey) lacks cytolytic activity of the complement and seems to have only the ACP of C3 activation. The complement system of cartilaginous fish (nurse shark) possesses the CCP which is composed of 6 functionally distinct components, but there is no indication of the existance of an ACP. On the other hand, bony fish have both of the pathways, directly comparable to those of mammals and thus far a number of complement components have been isolated from fish species. We have isolated C1, C4, C2, C3, C5, C6, C7, C8, C9, factor D and factor B from carp serum and have shown that these components interact basically in the same manner as their mammalian counterparts. It was also found that the ACP activity (ACH50) of bony fish was extremely high as compared with those of mammals, and that the function of the CCP of bony fish was only to fix C3 on target cells and triggers the activation of the ACP. These results suggest that the role of the ACP, which works effectively in the early stages of infection, is much more important in fish than in mammals. This paper describes the complement systems of fish concentrating upon that of bony fish.
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  • Masahiro Sakai
    1995 Volume 30 Issue 2 Pages 159-166
    Published: June 15, 1995
    Released: October 26, 2009
    JOURNALS FREE ACCESS
    The major histocompatibility complex (MHC) has attracted much attention because of its immense polymorphism, its importance in transplantation, and its indisputable role in disease susceptibility in humans and animals. Two classes of MHC have been identified. Class I MHC consists of two non-covalently attached polypeptide chains, the α chain and β2-microglobulin.The a chain is approximately 40-50 kDa in size, membrane bound, and is encoded by several genes within the MHC. Class II MHC also consists of two membrane-bound polypeptides, α and β, both of which are approximately 30 kDa in size and are encoded by genes within MHC. In fish, genes of polypeptides which contain MHC class I and class II have been identified and investigated. The size and organization of fish MHCs genes are similar to those of mammals. There are several loci encoding fish MHC and there is a high degree of polymorphism observed in the putative peptide-binding region of class I α, class II α and β chains. Thus, in spite of great sequence divergence between fish and mammalian MHC genes, their overall organizations are well conserved.
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  • Ikuo Hirono, Takashi Aoki
    1995 Volume 30 Issue 2 Pages 167-174
    Published: June 15, 1995
    Released: October 26, 2009
    JOURNALS FREE ACCESS
    Most studies of fish transferrins focus on their potential for discriminating genetic populations within species. Transferrin genes are polymorphic in most species of fish.There are three transferrin genotypes (A, B, andC) in coho salmon, and C type coho salmon is the most resistant to bacterial kidney disease.
    Fish transferrins have the same characteristics as the higher vertebrates, in such points as duplicated structure, conservative iron binding regions and cystein residues. The homology of amino acid sequences of medaka and Atlantic salmon transferrins and other members of the transfenin family range from30 to 50%. Medaka transferrin gene was consists of 17 exons, the same number as the higher vertebrates transferrin family genes. However, intron sizes of medaka transferrin gene are smaller than those of human transferrin gene.There are several transcriptional regulatory elements on the 5'up-stream region of the medaka transferrin gene. Medaka and Atlantic salmon transferrins are transcribed mostly in the liver.
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  • Hiroki Murakami, Tadakazu Tamai, Sanetaka Shirahata
    1995 Volume 30 Issue 2 Pages 175-180
    Published: June 15, 1995
    Released: October 26, 2009
    JOURNALS FREE ACCESS
    Fish interferon (FIFN) is expected to have a potential to play an important role in the prevention of viral infections in fish farming. Since a very small amount of FIFN is produced in fish body, it is quite difficult to purify it. Therefore, we first tried to immortalize lymphocytes of the Japanese flounder using a variety of oncogenes and found that the cotransfection of c-Ha-ras and c-fos was most effective. One of these immortalized lymphocyte cell lines, HL8, produced FIFN which was a glycoprotein of about 16kDa. The cloned FIFN cDNA is composed of a signal peptide region coding 30 amino acids and a structure gene coding a 108 amino acid chain including a potential Asn-linked glycosilation site. Therecombinant FIFN (rFIFN) produced by mammalian BHK-21 cells inhibited the propagation of threefish viruses in cell lines and infection with hirame rhabdovirus in rainbow trout by oral administration.The minimum effective amount of the rFIFN was 200pg/g-body weight.
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