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魚病研究の検索結果

もしかして: 魚病研究  魚病研究 投稿規定  魚病研究 jstage  魚病研究 台湾  魚病研究 33 

魚病研究 第54巻総目次(平成31年3月~令和2年1月) CiNiiでみる

著者名:

抄録:

出版年月日:
2020-01 , 
巻:
54 , 
号:
4 , 
ページ:
- , 
ISSN:
0388-788X

平成30年度日本魚病学会研究奨励賞 魚病細菌の動態と宿主との相互作用に関する研究 CiNiiでみる

著者名:
間野 伸宏 

抄録:

出版年月日:
2020-01 , 
巻:
54 , 
号:
4 , 
ページ:
79-82 , 
ISSN:
0388-788X

平成30年度日本魚病学会賞 冷水性魚介類の疾病とその防除に関する研究 CiNiiでみる

著者名:
熊谷 明 

抄録:

出版年月日:
2020-01 , 
巻:
54 , 
号:
4 , 
ページ:
71-78 , 
ISSN:
0388-788X

北海道内の飼育及び野生サケ科魚類に寄生する腸管鞭毛虫Spironucleus salmonisの定量解析 CiNiiでみる

著者名:
Mizuno Shinya  Urawa Shigehiko  Katsumata Yoshitomo  Morishita Takumi  Minowa Yui  Ban Masatoshi 

抄録:

Diplomonad flagellate Spironucleus salmonis infection in hatchery-reared juvenile chum salmon Oncorhynchus keta and masu salmon O. masou has been previously reported in Hokkaido, northern Japan. ​We established a quantitative real-time PCR (qPCR) assay for the S. salmonis ribosomal RNA gene (rDNA) using a fish intestine nucleic acid template, which we then use to investigate the infection intensity of S. salmonis in hatchery-reared, farmed, and wild salmonids throughout Hokkaido. ​Our new qPCR assay enabled the measurement of rDNA from 1.0–1.0 × 108 copies/μL. ​Our study reported a significantly positive correlation between parasite trophozoite cell number and its rDNA copy number, and presented this as a simple regression (parasite rDNA copy number = -768 + 338 × parasite cell number). ​By reporting S. salmonis infection in juvenile and/or adult chum and masu salmon collected from three hatcheries, one fish farm, and one river in Hokkaido, we demonstrate the utility of our qPCR assay for the surveillance of S. salmonis infection in hatchery-reared, farmed and wild fish.


出版年月日:
2020 , 
巻:
55 , 
号:
3 , 
ページ:
61-70 , 
ISSN:
0388-788X

人工アユ2系統に対するFlavobacterium psychrophilumの病原性の違い CiNiiでみる

著者名:
Nagai Takahiro  Nakai Toshihiro 

抄録:

The susceptibility of ayu Plecoglossus altivelis to infection by Flavobacterium psychrophilum differs among hatchery stocks. ​We challenged two ayu stocks, domesticated stock (DS) and amphidromous stock (AS), with 18 F. psychrophilum isolates derived from diseased ayu using intraperitoneal (IP) injection and immersion methods. ​In both methods, 6 isolates were more virulent to DS than to AS (designated as the Do pathotype), whereas the other 12 isolates were more virulent to AS than to DS (designated as the Am pathotype). ​The LD50s (CFU/fish) of the representative isolates, PH-1034 (Do pathotype) and PH-1037 (Am pathotype) by IP injection in DS and AS were 1.4 × 102 and 5.0 × 105, and 5.9 × 105 and 4.6 × 102, respectively. ​The difference in virulence between pathotypes was supported by the in vivo bacterial counts in the blood and organs of IP-challenged fish, but not by the in vitro growth ability in the serum of ayu, which is a virulence factor of F. psychrophilum. ​Additionally, the 18 F. psychrophilum isolates could be classified into any one of the previously reported PCR-RFLP-based genotypes. ​However, no clear correlation was found between these genotypes and pathotypes.


出版年月日:
2020 , 
巻:
55 , 
号:
3 , 
ページ:
71-79 , 
ISSN:
0388-788X

ウグイ種苗の腹腔にみられたメタセルカリアの重篤寄生 CiNiiでみる

著者名:
Komatsu Norihiko  Itoh Naoki  Ogawa Kazuo 

抄録:

In August 2013, metacercarial infection in the abdominal cavity of Japanese dace Tribolodon hakonensis fingerlings occurred at a hatchery in Nagano Prefecture, Japan. ​All fish examined in this study (n = 45) were infected, and heavily infected fish showed an abnormally distended abdomen and ascites, with the number of metacercariae reaching 66. ​The metacercariae were distinctly bipartite, representing a Neascus type and classified as a member of Diplostomidae, and phylogenetical analyses based on ITS2 and cox1 sequences tentatively classified them in the genus Posthodiplostomum. ​When they were excysted, only a few were alive and intact, suggesting that dace is not a suitable host. ​Histopathologically, cysts containing dead worms and empty and vestigial cysts were in the abdominal cavity, detached from the host visceral organs and surrounded by host inflammatory cells. ​Diplostomid cercarial larvae were not found in the three species of snails (n = 613) sampled from ponds in the station. ​At the end of rearing in September, the survival rate was 0.96% in a pond with a high infection rate, whereas it was 12.5% in another pond where fingerlings showed no clear disease signs. ​Oral administration of praziquantel at 150 mg/kg fish body weight for 3 consecutive days effectively killed metacercariae in the abdominal cavity.


出版年月日:
2020 , 
巻:
55 , 
号:
3 , 
ページ:
53-60 , 
ISSN:
0388-788X

過酸化水素浴がハダムシNeobenedenia girellaeの産卵と孵化に及ぼす影響 CiNiiでみる

著者名:
Hirazawa Noritaka  Umeda Naoko  Akiyama Kousuke 

抄録:

The effects of concentrations and exposure durations of H2O2 on the egg laying and egg hatching of Neobenedenia girellae were investigated. ​Four groups of eight adults or approximately 250 eggs were treated with H2O2 as follows: 0 ppm for 30 min (control), 300 ppm for 3 min; 75 ppm for 30 min; 100 ppm for 30 min. ​The adults in the H2O2 exposed groups produced significantly fewer number of normal eggs. ​Additionally, the H2O2 exposures to the eggs significantly reduced the hatching success of the eggs at < 24 h after laying, but the eggs at 48–71 h after laying were not affected.


出版年月日:
2020 , 
巻:
55 , 
号:
3 , 
ページ:
80-83 , 
ISSN:
0388-788X

アユのポックスウイルス様ウイルス検出のためのPCR法および定量PCR法の開発 CiNiiでみる

著者名:
Koyama Tomoki  Komatsu Daiki  Uchino Tsubasa  Midorikawa Yuki  Kato Goshi  Ishikawa Takanori  Nishimura Tomohiro  Takeda Korenori  Fukuda Hideo  Wada Shinpei  Sano Motohiko 

抄録:

Plecoglossus altivelis poxvirus-like virus (PaPV) is the presumptive causative agent of atypical cellular gill disease (ACGD), which has caused significant losses in aquaculture of ayu P. altivelis in Japan. ​In this study, we investigated a new PCR protocol and a quantitative PCR (qPCR) protocol with primers designed from the vaccinia virus A16L homologous gene sequence of PaPV. ​The new PCR showed a positive reaction for affected fish in all eight ACGD cases tested and no cross-reaction with carp edema virus, and was more sensitive than a PCR with BOKE30 primers. ​The qPCR quantified around 108–109 virus DNA copies/mg in the diseased fish gills.


出版年月日:
2020 , 
巻:
55 , 
号:
3 , 
ページ:
84-87 , 
ISSN:
0388-788X

養殖クロマグロにみられたハダムシについて CiNiiでみる

著者名:
八木 洋樹  浅井 七望  白樫 正  岡田 貴彦  高岡 治  升間 主計 

抄録:

これまで国内外の養殖クロマグロにおいてハダムシが寄生した例は報告されていない。2020年1月に鹿児島県奄美諸島にて養成中のクロマグロ親魚の衰弱個体にハダムシの寄生が確認され,形態的特徴と遺伝子解析の結果Neobenedenia girellaeであると同定されたので報告する。本種は宿主特異性が低く,多くの海産養殖魚に寄生するが,これまで寄生が著しいカンパチと同一海域で飼育されているクロマグロでもみつかったことは無く,世界的にもマグロ類における寄生例はない。今回の事例によりN. girellaeがクロマグロにも寄生することが初めて明らかとなったが,何らかの要因で衰弱した個体で発生した例外的な寄生だと考えられた。


出版年月日:
2020 , 
巻:
55 , 
号:
3 , 
ページ:
88-90 , 
ISSN:
0388-788X

光周期による海産白点虫Cryptocaryon irritansの宿主離脱および仔虫放出における日周リズムの操作(英文) CiNiiでみる

著者名:
Watanabe Yuho  How Kah Hui  Zenke Kosuke  Itoh Naoki  Yoshinaga Tomoyoshi 

抄録:

Cryptocaryon irritans has clear daily rhythms in protomont detachment from fish and theront excystment from tomonts. ​While the rhythms seem to be regulated by photoperiods, it has not been confirmed. ​We investigated whether the daily rhythms of the parasite would be controlled by giving different photoperiods of 12 h light and 12 h dark (06:00–18:00 L and 18:00–06:00 D; 15:00–03:00 L and 03:00–15:00 D) to infected fish and tomonts. ​Protomont detachment and theronts excystment mostly occurred in the last 3 h of the dark period and from 6 h to 3 h before the end of dark period, respectively, indicating that the rhythms are controlled by photoperiods.


出版年月日:
2020 , 
巻:
55 , 
号:
2 , 
ページ:
38-41 , 
ISSN:
0388-788X

シロサケ回帰親魚の細菌性冷水病原因菌Flavobacterium psychrophilumの保有とふ化場での垂直感染の防除 CiNiiでみる

著者名:
小林 俊将  高橋 憲明 

抄録:

2018年9月~12月に岩手県の明戸川さけますふ化場で採卵に使用したシロサケ雌親魚の体腔液から細菌性冷水病原因菌Flavobacterium psychrophilumが検出された。冷水病菌の検出率は河川で採捕した河川遡上親魚で0.0~91.7%,定置網で採捕して1~2週間淡水蓄養した海産親魚で0.0~100.0%だった。淡水蓄養をしなかった海産親魚の体腔液からも冷水病菌が検出された(検出率:21.4%)。同ふ化場では,2018年に累計で21,165,000粒の受精卵を吸水前消毒し,平均発眼率は92.4%だった。吸水前消毒をしない対照区では3ロット中1ロットで発眼卵の卵内から冷水病菌が検出された(検出率:23.3%)。吸水前消毒した試験区では4ロット全てで卵内感染は認められなかった。これらのことから,シロサケふ化場における事業規模の種苗生産において,吸水前消毒は冷水病菌の卵内感染の防除に有効であることが示された。


出版年月日:
2020 , 
巻:
55 , 
号:
2 , 
ページ:
42-45 , 
ISSN:
0388-788X

細菌性溶血性黄疸 CiNiiでみる

著者名:
高野 倫一  松山 知正 

抄録:

Bacterial hemolytic jaundice (BHJ) was first described in populations of cultured yellowtail, Seriola quinqueradiata in 1980 in Japan. ​BHJ is now one of the most important diseases of farmed yellowtail. ​The taxonomic position of the causative agent, Ichthyobacterium seriolicida, was recently determined as a single clade within the order Flavobacteriales and was distinct from the known clades of the family Flavobacteriaceae, Blattabacteriaceae and Cryomorphaceae. ​Whole genome analysis of the type strain JBKA-6T revealed that this bacterium harbors a single circular chromosome. ​Polymorphic analyses of I. seriolicida identified four major clusters among I. seriolicida isolates, and all belonged to clonal complexes; thus, this bacterium is considered to be recently introduced in Japan. ​In passive immunization tests, significantly lower mortality was observed in fish that received the serum from a convalescent fish, indicating I. seriolicida is neutralized by the humoral component of the immune system. ​However, since this bacterium does not grow vigorously in vitro, control measures such as the production of an inactivated vaccine is under development.


出版年月日:
2020 , 
巻:
55 , 
号:
2 , 
ページ:
25-30 , 
ISSN:
0388-788X

稚魚期に異なる発達を示したアユ胸腺のその後の変化(英文) CiNiiでみる

著者名:
Takada Yuzo  Taguchi Kosei  Suzuki Kyuma  Ashizawa Akihiko  Kaji Koichi  Watanabe Shun  Wada Shinpei  Kurata Osamu 

抄録:

The temperature of water used to rear juvenile stages of ayu affects the development of the thymus. ​However, subsequent differences in the thymus in adults after rearing juveniles at different temperatures are unclear. ​We analyzed thymus development of ayu grown at a constant water temperature of 15°C from juveniles reared at different water temperatures. ​Juvenile ayu weighed at 0.6 g and 1.4 g were reared at different temperatures (10°C, 12°C, 15°C, 18°C and 22°C) for 64 days and 54 days, respectively, and then held at 15°C for analysis of the thymus development. ​Thymus volume was measured by computed tomography and thymus development of experimental fish was evaluated as the ratio of thymus volume to body length. ​The thymus volume ratios of juveniles immediately after rearing at lower water temperatures (10°C, 12°C) were higher than in those reared at the higher temperatures (18°C, 22°C). ​These levels of thymus volume ratio were preserved in grown ayu continuously reared at 15°C. ​After the summer solstice, the thymus began to atrophy and no longer exhibited differences among the experimental groups. ​Thus the thymus formed at the juvenile stage retains its morphological properties until the summer solstice.


出版年月日:
2020 , 
巻:
55 , 
号:
2 , 
ページ:
31-37 , 
ISSN:
0388-788X

Prevalence of Infection with Nocardia seriolae in Juvenile of Yellowtail Seriola quinqueradiata Cultured in Owase Bay, Japan CiNiiでみる

著者名:
Kato Goshi  Oka Kensuke  Matsumoto Megumi  Kanemaru Motohisa  Yamamoto Masato  Sano Motohiko 

抄録:

Nocardiosis caused by Nocardia seriolae makes severe losses of fish production of Seriola spp. in Japan. ​In this study, we investigated prevalence of N. seriolae infection in yellowtail Seriola quinqueradiata cultured in an open sea net-cage in Owase Bay, Japan. ​The gills, serum and spleen were sampled from juvenile fish (n = 5) on May, June, July, August, November 2017 and January 2018. ​Serum antibody titer against N. seriolae were significantly increased on November 2017 and January 2018. ​N. seriolae 16S rRNA gene were detected by PCR in the spleen and/or gills of 1–4 individuals sampled on May, July, August, November 2017 and January 2018, while the bacterium was not isolated from any individuals on Ogawa medium. ​Granulomatous inflammation which is the typical characteristic of pathological feature of nocardiosis was not observed in any spleen sections examined. ​However, fluorescent immunohistochemistry with anti-N. seriolae rabbit serum detected the long- and short-rod shaped bacteria in the spleen of all fish examined in this study. ​These data suggest that the juvenile yellowtail cultured in Owase Bay had been already infected with N. seriolae even in May. ​In addition, N. seriolae may be in viable but non-culturable state (VBNC), resulting in latent infection in cultured yellowtail.


出版年月日:
2020 , 
巻:
55 , 
号:
1 , 
ページ:
1-7 , 
ISSN:
0388-788X

Ultrastructural and Molecular Phylogenetic Identification of the Diplomonad Flagellate Spironucleus salmonis Infecting Hatchery-reared Salmonid Fishes in Hokkaido CiNiiでみる

著者名:
Mizuno Shinya  Urawa Shigehiko  Katsumata Yoshitomo  Morishita Takumi  Ban Masatoshi 

抄録:

Systemic infections caused by diplomonad flagellates belonging to the genus Spironucleus commonly result in heavy mortalities in salmonids. ​Diplomonad flagellates were found in the intestinal lumen of hatchery-reared juvenile chum Oncorhynchus keta and masu salmon O. masou in Hokkaido. ​We performed ultrastructural observation and molecular phylogenetic analysis using the small subunit ribosomal RNA gene (SSUrDNA) of the flagellates to clarify their taxonomy. ​The flagellates showed elongated and tapered nuclei, and sub-apical location of the kinetosomes relative to the nuclei: which are the distinguishing characters of the genus Spironucleus among three genera of parasitic diplomonads. ​In addition, the flagellates had electron dense plaques at their posterior end, a posterior sac of dense free ribosomes, an electron dense body, and bowl-shaped membranous structures, identifying them as S. salmonis among four Spironucleus species that affect fish. ​The ultrastructure of the flagellates showed no variations between the two host species of salmon. ​All the isolated flagellate SSUrDNAs had the same 1,031 bp sequence, and no difference in the sequence. ​The SSUrDNA showed the highest homology (99%) with S. salmonis among 11 diplomonad flagellates. ​Thus, this study successfully used ultrastructure diagnosis and molecular phylogenetic analysis to confirm S. salmonis as the diplomonad flagellate that has infected hatchery-reared chum and masu salmon in Hokkaido.


出版年月日:
2020 , 
巻:
55 , 
号:
1 , 
ページ:
8-17 , 
ISSN:
0388-788X

Comparative Analysis of Plasmid DNAs from Two Strains of Photobacterium damselae subsp. piscicida Isolated from Japan and the United States CiNiiでみる

著者名:
Tsuchiya Akito  Nishihara Aki  Saeki Ayumi  Teru Yuki  Aoki Takashi  Kono Tomoya  Sakai Masahiro  Hikima Jun-ichi 

抄録:

Pseudotuberculosis pathogen, Photobacterium damselae subsp. piscicida (Pdp) shows some differences in virulence between Japanese and US strains. ​In this study, we analyzed plasmid DNAs derived from Japanese and US strains of Pdp, and found two homologous regions in these plasmids, pOT-51443-4/p91-197-1 and pOT-51443-1/p91-197-2. ​All genes in the p91-197-1 from US strain were observed in the pOT-51443-4 from Japanese strain. ​This event might have occurred during transmission of the US plasmid to Japanese strain. ​Inhibitor of vertebrate lysozyme (ivy), a known pathogenicity factor was encoded in the homologous region of pOT-51443-1/p91-197-2. ​Thus, the genomic region containing ivy may have been horizontally transmitted between the two Pdp strains.


出版年月日:
2020 , 
巻:
55 , 
号:
1 , 
ページ:
18-21 , 
ISSN:
0388-788X

メラニン色素を持つ魚の全身透明化と内部構造可視化のための蛍光核染色 CiNiiでみる

著者名:
Futami Kunihiko  Furukawa Oto  Maita Masashi  Katagiri Takayuki 

抄録:

Recently, our lab reported that CUBIC, a tissue-clearing technique, could help reveal the initial route of infection, its spread, and the localization of pathogens in infected goldfish Carassius auratus. ​However, this technique, in its original form, failed to clear melanin pigmented parts of the fish. ​We show here that bleaching with H2O2 clears melanin pigments of Black Moor goldfish without causing severe histological damage. ​Furthermore, nuclear staining with PI helps visualize the internal structures of cleared fish in a dark field. ​Since bleaching does not significantly quench the fluorescence of GFP, it may be applied to the in vivo imaging of GFP.


出版年月日:
2020 , 
巻:
54 , 
号:
4 , 
ページ:
101-103 , 
ISSN:
0388-788X

ファージディスプレイ法を利用した抗マダイイリドウイルス抗体M10のエピトープ決定 CiNiiでみる

著者名:
Takano Tomokazu  Matsuyama Tomomasa  Kawato Yasuhiko  Sakai Takamitsu  Kurita Jun  Matsuura Yuta  Terashima Sachiko  Nakajima Kazuhiro  Nakayasu Chihaya 

抄録:

Red sea bream iridoviral disease (RSIVD) spreads readily throughout the marine environment because of its wide variety of host species. Use of a rapid diagnostic method, such as the immunofluorescence antibody test, helps to control the disease, so the anti-RSIV monoclonal antibody M10 (mAb M10) has been developed in Japan. In the present study, we carried out epitope mapping using the phage display method to identify the antigen of mAb M10. A phage display RSIV peptide library was constructed to cover the entire genome of RSIV, then phage clones recognized by the antibody were selected by biopanning. The selected clones harbored partial fragments of the laminin-type epidermal growth factor-like domain (LEGFD) gene. N-terminal and C-terminal deletion peptides were then prepared from the amino acid sequence deduced from the smallest fragment to precisely determine the epitope. Finally, seven amino acids, EYDCPEY, located in the extracellular domain of the LEGFD protein were determined to be the epitope. Identical residues of the epitope were also identified from the LEGFD protein in other megalocytiviruses including the infectious spleen and kidney necrosis virus and turbot reddish body iridovirus. mAb M10 is considered to be widely available for the diagnostics of megalocytivirus infections.


出版年月日:
2020 , 
巻:
54 , 
号:
4 , 
ページ:
83-92 , 
ISSN:
0388-788X

天然海産アユ仔稚魚にみられた腹口吸虫のメタセルカリア寄生 CiNiiでみる

著者名:
Shirakashi Sho  Waki Tsukasa  Ogawa Kazuo 

抄録:

Ayu Plecoglossus altivelis is a native amphidromous fish in Japan and an important target for farming and recreational fishing. ​We have found high infection of hitherto unknown digenean metacercariae in wild ayu larvae and juveniles captured from the sea and a river in Wakayama Prefecture. ​The infection prevalence was 95% and 100% in larvae and juvenile ayu, respectively with variable intensities up to 566 metacercariae per fish. ​The metacercariae were located primarily around fins and inside caudal fins, but appeared to cause no serious pathological features to the fish. ​The phylogenetic analysis based on the internal transcribed spacer 2 and 28S rDNA sequences revealed its identity as a member of Bucephalinae (Bucephalidae) with no identical genetic information on the database. ​Morphological characteristics of the larval trematode resembled those of the genus Prosorhynchoides. ​Genetically identical metacercariae were also found from Scomber japonicus and Engraulis japonicus captured at the same location as P. altivelis with variable infection levels, which suggested that it was a marine species. ​Experimental infection challenge of the metacercariae to several marine fish via oral intubation failed to obtain adult specimen and thus the precise identification of the parasite remains unknown.


出版年月日:
2020 , 
巻:
54 , 
号:
4 , 
ページ:
93-100 , 
ISSN:
0388-788X

中国,チワンで養殖される交雑ハタ(アカマダラハタ♀×タマカイ♂)からの神経壊死症ウイルスの分離 CiNiiでみる

著者名:
Yu Q.  Liu M.  Wei S.  Xiao H.  Wu S.  Qin X.  Shi D.  Li S.  Wang T.  Li P. 

抄録:
2018年8月,中国,チワンで養殖されるハタ類にウイルス性神経壊死症と疑われる疾病が発生した。病理組織学観察では病魚の脳に重度の空胞変性がみられた。ハタ脳由来EAGB細胞を用いて病魚の脳と眼球のプール試料から神経壊死症ウイルスが分離された。このGNNV-Gx分離株はEAGB細胞において細胞質の空胞変性を特徴とするCPEを引き起こした。ウイルスコートタンパク質遺伝子配列はtiger grouper由来のウイルスと最も高い相同性を示した。この分離株はpH3と10および60℃に感受性を示した。

出版年月日:
2019-03 , 
巻:
54 , 
号:
1 , 
ページ:
16-19 , 
ISSN:
0388-788X