KINAMI Ryuhei

Aquaculture Research Institute, Kindai UniversityResearch associate

Last Updated :2024/07/20

■Researcher basic information

Researcher number

70842384

ORCID ID

0000-0001-8972-0159

■Research activity information

Paper

  • Naoki Kabeya; Kazunori Kimura; Yoshiyuki Matsushita; Satoshi Suzuki; Yasuhiro Nagakura; Ryuhei Kinami; Hiroyuki Noda; Koji Takagi; Kazutoshi Okamoto; Misako Miwa; Yutaka Haga; Shuichi Satoh; Goro Yoshizaki
    Fish physiology and biochemistry 49 (3) 425 - 439 2023/06 
    The splendid alfonsino Beryx splendens is a commercially important deep-sea fish in East Asian countries. Because the wild stock of this species has been declining, there is an urgent need to develop aquaculture systems. In the present study, we investigated the long-chain polyunsaturated fatty acid (LC-PUFA) requirements of B. splendens, which are known as essential dietary components in many carnivorous marine fish species. The fatty acid profiles of the muscles, liver, and stomach contents of B. splendens suggested that it acquires substantial levels of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) from its natural diet. The functional characterization of a fatty acid desaturase (Fads2) and three elongases (Elovl5, Elovl4a, and Elovl4b) from B. splendens confirmed their enzymatic capabilities in LC-PUFA biosynthesis. Fads2 showed Δ6 and Δ8 bifunctional desaturase activities. Elovl5 showed preferential elongase activities toward C18 and C20 PUFA substrates, whereas Elovl4a and Elovl4b showed activities toward various C18-22 substrates. Given that Fads2 showed no Δ5 desaturase activity and no other fads-like sequence was found in the B. splendens genome, EPA and arachidonic acid cannot be synthesized from C18 precursors; hence, they can be categorized as dietary essential fatty acids in B. splendens. EPA can be converted into DHA in B. splendens via the so-called Sprecher pathway. However, given that fads2 is only expressed in the brain, it is unlikely that the capacity of B. splendens to biosynthesize DHA from EPA can fulfill its physiological requirements. These results will be useful to researchers developing B. splendens aquaculture methods.
  • 木南 竜平; 渡邊 清
    静岡県水産技術研究所研究報告 = Bulletin of Shizuoka Prefectural Research Institute of Fishery 静岡県水産技術研究所 (48) 27 - 30 1883-0382 2015/10 
    ニジマスの稚魚におけるPITタグの装着が生残及び成長に及ぼす影響について検討した。PITタグを装着した標識魚の死亡がごくわずかであったこと,PITタグを装着していない対照魚と成長に差がなかったことから,PITタグの装着は生残率や成長速度に悪影響を与えないと判断された。従って,ニジマスを対象として生残や成長を指標とするQTL解析を目的とした飼育実験を行う際にPITタグを使用することは可能であることが明らかとなった。
  • Sho Hosoya; Shinichi Kido; Yo Hirabayashi; Wataru Kai; Ryuhei Kinami; Tomoyoshi Yoshinaga; Kazuo Ogawa; Hiroaki Suetake; Kiyoshi Kikuchi; Yuzuru Suzuki
    International journal for parasitology 43 (11) 909 - 15 2013/10 
    The genetic mechanisms underlying host specificity of parasitic infections are largely unknown. After hatching, the larvae of the monogenean parasite, Heterobothrium okamotoi, attach to the gill filaments of hosts and the post-larval worms develop there by consuming nutrients from the host. The susceptibility to H. okamotoi infection differs markedly among fish species. While this parasite can grow on tiger pufferfish (also called fugu), Takifugu rubripes, it appears to be rejected by a close congener, grass pufferfish, Takifugu niphobles, after initial attachment to the gills. To determine the genetic architecture of the pufferfish responsible for this host specificity, we performed genome-wide quantitative trait loci analysis. We raised second generation (F2) hybrids of the two pufferfish species and experimentally infected them with the monogenean in vivo. To assess possible differences in host mechanisms between early and later periods of infection, we sampled fish three h and 21days after exposure. Genome scanning of fish from the 3h infection trial revealed suggestive quantitative trait loci on linkage groups 2 and 14, which affected the number of parasites on the gill. However, analysis of fish 21days p.i. detected a significant quantitative trait locus on linkage group 9 and three other suggestive quantitative trait loci on linkage groups 7, 18 and 22. These results indicated the polygenic nature of the host mechanisms involved in the infection/rejection of H. okamotoi. Moreover the analyses suggested that host factors may play a more important role during the growth period of the parasite than during initial host recognition at the time of attachment. Within the 95% confidence interval of the linkage group 9 quantitative trait locus in the fugu genome, there were 214 annotated protein-coding genes, including immunity-related genes such as Irak4, Muc2 and Muc5ac.
  • Sho Shirakashi; Yoshiki Kishimoto; Ryuhei Kinami; Hiromitsu Katano; Katsuya Ishimaru; Osamu Murata; Naoki Itoh; Kazuo Ogawa
    Parasitology international 61 (2) 242 - 9 2012/06 
    Infestations of blood flukes of the genus Cardicola have been observed in juvenile Pacific bluefin tuna (PBT) cultured in Japan. Infected fish harbor large numbers of parasite eggs in their gills. Although the link between blood fluke infection and juvenile mortality is not clear, accumulation of parasite eggs appears to be pathogenic to the fish. We investigated the origins, general morphology/distribution, and histopathology of these eggs in artificially produced 0 yr old PBT. Dead and live fish were sampled on several occasions from two culture facilities in Wakayama prefecture, Japan. The number of eggs in each gill filament was enumerated under a microscope. In addition, we estimated the total number of eggs by dissolving the gills in a weak NaOH solution. We observed two morphologically distinct egg types in the gill filaments, smaller, oval shaped eggs in the gill lamellae and larger, crescent shaped eggs that occurred primarily in the filamentary arteries. Based on the ITS2 sequence, the ovoid and crescent shaped eggs were identified as C. orientalis and C. opisthorchis, respectively. Eggs of the former species were more abundant (maximum: 6400 per filament) than the latter (maximum: 1400), but the number was highly variable among filaments. The eggs of the latter species were relatively evenly distributed among the filaments. In a heavily infected individual, we estimated a total of >4.5 million eggs were present in the gills on one side of the fish. The number of eggs from the two species was positively correlated to each other and the dead fish tended to harbor more eggs than the live fish. Histological observation revealed host responses around the eggs, including encapsulation by fibroblasts and nodule formation, as seen in response to other aporocotylid eggs. In addition, we observed widespread fusion of gill lamellae and blockage of the filamentary arteries in some instances. Our results provide information that can be used for routine diagnosis of Cardicola blood flukes in cultured tuna and suggest they represent a risk to juvenile PBT.
  • 木南 竜平
    日本水産學會誌 = Bulletin of the Japanese Society of Scientific Fisheries 公益社団法人 日本水産学会 78 (3) 495 - 496 0021-5392 2012/05
  • D. S. Grabner; H. Yokoyama; S. Shirakashi; R. Kinami
    Aquaculture 338-341 36 - 40 0044-8486 2012/03 
    Kudoa infections in muscle tissue can be a serious problem for fisheries and aquaculture of olive flounder (Paralichthys olivaceus) due to post-mortem myoliquefaction that makes the fish unmarketable. Recently, cases of a new food poisoning of human associated with ingestion of raw olive flounder infected with Kudoa septempunctata have increased in Japan. In the present study, diagnostic PCR assays were developed to detect and distinguish Kudoa spp. from olive flounder muscle. Kudoa 18S and 28S rDNA were amplified from infected fish by universal primers and sequenced. Blast searches with the obtained sequences revealed the presence of not only K. septempunctata and K. thyrsites, but also K. lateolabracis which was detected for the first time in olive founder. Comparison of the 28S rDNA sequences obtained from K. thyrsites isolated in the present study with a previous isolate from GenBank indicated the existence of two genetic lineages of this species, both infecting olive flounder. Alignments of partial 28S rDNA sequences were used to design primers for each of the three Kudoa spp. Specificity of each primer pair was tested by PCR with DNA from different myxozoans and host DNA. For sensitivity testing, the target sequence was ligated into a plasmid vector and cloned. PCR was conducted with host DNA spiked with dilution series of the plasmid. Additionally, a practical test of the primers was conducted in comparison to classical diagnostic methods with 10 olive flounders from a fish farm suspected to be infected with Kudoa spp. All three primer pairs were specific for the respective parasite and amplified neither host DNA nor DNA of other tested myxozoans. Primers for K. septempunctata approximately amplified down to 0.06, those for K. thyrsites 0.001 and for K. lateolabracis 0.1 spores per reaction (240, 4 and 400 spores per 1. g of muscle tissue). The diagnostic PCR assay developed in this study was shown to be more effective for detection of K. septempunctata from cultured olive flounder (10 out of 10 fish positive) than microscopic detection of spores in tissue homogenates (5 out of 10 fish positive). K. thyrsites and K. lateolabracis were not detected in the 10 flounders tested. This novel PCR assay will facilitate the screening and monitoring process for Kudoa infections and allow improved disease management in olive flounder aquaculture facilities. It will also improve food safety testing to avoid human consumption of Kudoa infected fillets. © 2012 Elsevier B.V.
  • YOSHINAGA Tomoyoshi; KINAMI Ryuhei; HALL Kathryn A.; OGAWA Kazuo
    Fish Pathology The Japanese Society of Fish Pathology 41 (3) 123 - 126 0388-788X 2006/09 
    Juvenile greater amberjack Seriola dumerili (fork length: 39.5-43.0 cm) imported from China to Japan as mariculture seedlings were found infected with larval anisakid nematodes in the spring of 2005. The parasite was morphologically identified as Anisakis type I larva causing human anisakiasis. Based on the nucleotide sequence of ITS1-5.8S rRNA-ITS2 region, the parasite was tentatively identified as A. pegreffii, one of the species comprising A. simplex sensu lato. The main infection site was the wall and serous membrane of the stomach. No worms were found in the ventral side of the body muscle of fish. This is the first documented case of Anisakis infection in cultured marine fishes.
  • KINAMI Ryuhei; MIYAMOTO Junko; YOSHINAGA Tomoyoshi; OGAWA Kazuo; NAGAKURA Yoshitomo
    Fish Pathology The Japanese Society of Fish Pathology 40 (2) 63 - 66 0388-788X 2005/06 
    A practical method to distinguish two pathogenic monogeneans of fish, Neobenedenia girellae and Benedenia seriolae, is described.N. girellae and B. seriolae were obtained from experimentally infected olive flounder Paralichthys olivaceus and yellowtail Seriola quinqueradiata, respectively, by freshwater bathing and fixed in 10% formalin. The two species were found to have a different shape at the anterior end in the midline of the body and are clearly distinguishable by this difference. Using this method, the ratio of these two parasite species was monitored in greater amberjack Seriola dumerili cultured in net cages at Amami-Oshima Island for one year. A seasonal shift of abundance between the two species was observed.

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