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NO49 - 3

Identification and Molecular Characterization of Z/ZE Lineage MHC Class I Heavy Chain Homologue and β2-microglobulin from Rock Bream Oplegnathus fasciatus

Chamilani Nikapitiya1, Sung-Ju Jung1*, Myung-Hwa Jung1,2, Jun-Young Song3, Jehee Lee4, Jeong-Ho Lee5and Myung-Joo Oh1

1Department of Aqualife Medicine, Chonnam National University, Chonnam 550-749, Korea
2Aquatic Animal Hospital, Chonnam National University, Chonnam 550-749, Korea
3National Fisheries Research and Development Institute, Busan 619-705, Korea
4Department of Marine Life Sciences, School of Marine Biomedical Sciences, Jeju National University, Jeju Special Self-Governing Province 690-756, Korea
5Genetics and Breeding Research Center, National Fisheries Research and Development Institute, Geoje 656-842, Korea

(Received October 9, 2013)

ABSTRACT―We identified and characterized full-length cDNAs of rock bream Oplegnathus fasciatus major histocompatibility complex (RbMHC) class I and β2-microglobulin (Rbβ2m) molecules. The full-length RbMHC class I cDNA was 2,667 bp with a 1,227 bp open reading frame encoding 409 amino acids (aa). The Rbβ2m full-length cDNA (1,339 bp) consisted of a 354 bp coding region, encoding 118 aa. RbMHC class Iβ was clustered with the Z/ZE lineage of known MHC class I sequences, suggesting a novel molecule belonging to the Z/ZE lineage. Although characteristic features (residues and motifs) known to be conserved in classical and non-classical class I molecules were conserved in RbMHC class Ia with few modifications, it is more closely resembled to classical MHC class I. RbMHC class I and Rbβ2m were transcribed constitutively in healthy fish, but expression differed among the different organs and was highest in whole blood. Low sequence variation in the RbMHC class I β1 region makes it uncertain whether the molecule belongs to the non-classical group. However, because transcription was induced by megalocytivirus, the molecule is most likely a member of the classical group. Our results provide important information for future studies on antigen presentation and cytotoxic CD8+ T cell responses in rock bream against infectious pathogens.

Key words: MHC class I, Z/ZE lineage, β2-microglobulin, Oplegnathus fasciatus, rock bream

Oral Passive Immunization of Carp Cyprinus carpio with Anti-CyHV-3 Chicken Egg Yolk Immunoglobulin (IgY)

Zhenxing Liu1,2, Hao Ke2*, Yanping Ma2, Le Hao2, Guoqing Feng2, Jiangyao Ma2, Zhiling Liang2 and Yugu Li1*

1College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, China
2Institute of Animal Heath, Guangdong Academy of Agricultural Sciences, Guangzhou 510640, China

(Received November 22, 2013)

ABSTRACT―Cyprinid herpesvirus 3 (CyHV-3), also called as koi herpesvirus, has spread all over the world since its emergence in the late 1990s. CyHV-3 causes a fatal disease, which leads to a mortality rate of more than 80% in common and ornamental (koi) carp Cyprinus carpio. The novel anti-CyHV-3 strategies are urgently needed. In this report, CyHV-3 particles were concentrated and then used for the immunization of hens in order to obtain the anti-CyHV-3 egg yolk immunoglobulin (IgY). The proportion of anti-CyHV-3 IgY to total IgY in water-soluble fraction of egg york increased from 0.014% to 23.9% after three times of immunization. The anti-CyHV-3 effects of IgY were then examined by in vivo and in vitro assays. The results suggested that the anti-CyHV-3 serum of hens and the purified anti-CyHV-3 IgY from eggs could prevent common carp brain (CCB) cells from infection. After oral passive immunization with IgY, the mortality of carp significantly decreased from 85% to 50% (P < 0.05) when the fish were challenged with CyHV-3 at a dose of 40 TCID50/fish. These results will possibly pave the way for the prevention of CyHV-3 infection.

Key words: Cyprinid herpesvirus 3, KHV, carp, yolk immunoglobulin, IgY, oral passive immunization

Biological and Serological Characterization of a Non-gliding Strain of Tenacibaculum maritimum Isolated from a Diseased Puffer Fish Takifugu rubripes

Tanvir Rahman1, Koushirou Suga1, Kinya Kanai1* and Yukitaka Sugihara2

1Graduate School of Fisheries Science and Environmental Studies, Nagasaki University, Nagasaki 852-8521, Japan
2Nagasaki Prefectural Institute of Fisheries, Nagasaki 851-2213, Japan

(Received April 1, 2014)

ABSTRACTTenacibaculum maritimum is a Gram-negative, gliding marine bacterium that causes tenacibaculosis, an ulcerative disease of marine fish. The bacterium usually forms rhizoid colonies on agar media. We isolated T. maritimum that formed slightly yellowish round compact colonies together with the usual rhizoid colonies from a puffer fish Takifugu rubripes suffering from tenacibaculosis, and studied the biological and serological characteristics of a representative isolate of the compact colony phenotype, designated strain NUF1129. The strain was non-gliding and avirulent in Japanese flounder Paralichthys olivaceus in immersion challenge test and showed lower adhesion ability to glass wall in shaking broth culture and to the body surface of flounder. It lacked a cell-surface antigen commonly detected in gliding strains of the bacterium in gel immunodiffusion tests. SDS-PAGE analysis showed different polypeptide banding patterns between NUF1129 and gliding strains. Like gliding strains, NUF1129 exhibited both chondroitinase and gelatinase activities, which are potential virulence factors of the bacterium. These results suggest that some cell-surface components related to gliding and adhesion ability are implicated in the virulence of T. maritimum.

Key words: Tenacibaculum maritimum, tenacibaculosis, non-gliding, virulence, adherence, cell-surface antigen

Pharmacological Characteristics of the Formalin-Killed Vaccines against Streptococcus iniae and Lactococcus garvieae in Farmed Thread-sail Filefish

Takayuki Minami1*, Kazuo Iwata1, Masakazu Kuwahara2, Kenichi Amano2, Atushi Mizuta3, Azumi Yamashita4, Yutaka Fukuda5, Issei Nishiki6, Yuya Tue6 and Terutoyo Yoshida6

1Miyazaki Prefectural Fisheries Research Institute, Miyazaki 889-2162, Japan
2Matsuoka Research Institute For Science, Tokyo 184-0003, Japan
3Miyazaki Prefectural Fisheries Promotion Association, Miyazaki 819-0322, Japan
4Center for Marine Studies, Ehime Prefectural Research Institute for Agriculture, Forestry and Fisheries, Ehime 798-0087, Japan
5Fisheries Research Division, Oita Prefectural Agriculture, Forestry and Fisheries Research Center, Oita 879-2602, Japan
6Faculty of Agriculture, University of Miyazaki, Miyazaki 889-2192, Japan

(Received April 15, 2014)

ABSTRACT―In the previous study, we evaluated the protective efficacies of the following three vaccines for the thread-sail filefish Stephanolepis cirrhifer: a commercial Streptococcus iniae vaccine, a commercial Lactococcus garvieae vaccine and a combination of these two vaccines. In this study, we examined the three vaccines for the thread-sail filefish in terms of protective duration, protection against various heterogeneous strains of S. iniae and L. garvieae, and the effects of different water temperatures on the protection. The vaccines induced strong protection against heterogeneous strains of S. iniae and L. garvieae, and the protection was observed for 52 weeks after the vaccination. These vaccines also induced protective immunity when administrated at 15°C, 20°C and 25°C.

Key words: thread-sail filefish, Streptococcus iniae, Lactococcus garvieae, vaccine, protective duration, vaccination temperature

Efficacy of High Water Temperature Treatment of Myxosporean Emaciation Disease Caused by Enteromyxum leei (Myxozoa)

Machiko China1, Hiroyuki Nakamura2, Kaoru Hamakawa3, Eishin Tamaki2, Hiroshi Yokoyama4*, Sota Masuoka4and Kazuo Ogawa5

1Yaeyama Agriculture, Forestry and Fisheries Promotion Center, Okinawa 907-0002, Japan
2Okinawa Prefectural Sea Farming Center, Okinawa 905-0212, Japan
3Okinawa Prefectural Fisheries Research and Extension Center, Okinawa 901-0305, Japan
4Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo 113-8657, Japan
5Meguro Parasitological Museum, Tokyo 153-0064, Japan

(Received January 30, 2014)

ABSTRACT―The effect of elevated water temperature on the myxosporean emaciation disease caused by Enteromyxum leei was tested in experimentally infected anemonefish Amphiprion ocellaris and naturally infected Malabar grouper Epinephelus malabaricus. Anemonefish reared at 30°C following infection had significantly lower parasite prevalence compared to fish reared at 23°C. After infection in anemonefish held at 23°C for 20 days, elevation of water temperature to 30°C reduced the prevalence. Holding infected Malabar grouper at 30°C resulted in a clearing of E. leei within 6 days. Histopathological observations showed that E. leei was eliminated following exfoliation of the intestinal epithelial cells. Although further replication of the study would be required, these results suggested that high water temperature treatment had a preventive and therapeutic effect on myxosporean emaciation disease.

Key words: Enteromyxum leei, myxosporean emaciation disease, Epinephelus malabaricus, high water temperature treatment, Amphiprion ocellaris

Effectiveness of Ultraviolet Irradiation of Seawater for the Prevention of Kudoa yasunagai and Kudoa amamiensis (Myxozoa: Multivalvulida) Infections in Seriola Fish

Sho Shirakashi1*, Tomoyo Nishimura1, Nagaharu Kameshima1, Hiroshi Yamashita1, Hiroe Ishitani1, Katsuya Ishimaru1 and Hiroshi Yokoyama2

1Fisheries Laboratory, Kinki University, Wakayama 649-2211, Japan
2Department of Aquatic Bioscience, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo 113-8657, Japan

(Received April 28, 2014)

ABSTRACTKudoa infections have recently become a serious concern in Japanese fisheries. Some species not only cause fish diseases and reduce the commodity value of fish, but also affect human health. We investigated whether the ultraviolet (UV) treatment of culture water prevented infections with two species of Kudoa, K. yasunagai and K. amamiensis, in Seriola lalandi and S. quinqueradiata, respectively. Rearing in untreated filtered seawater resulted in high infection rates, suggesting that the physical filtration systems used in this study did not sufficiently remove the infective stages of these Kudoa species. In contrast, commercially available UV irradiation system effectively prevented the infections with K. yasunagai and K. amamiensis.

Key words: Kudoa yasunagai, Kudoa amamiensis, ultraviolet irradiation, prevention