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Last Updated :2024/07/25

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Master

Affiliation (Master)

  • Faculty of Fisheries Sciences　Marine Life Science　Marine Biotechnology and Microbiology

Affiliation (Master)

  • Faculty of Fisheries Sciences　Marine Life Science　Marine Biotechnology and Microbiology

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Profile and Settings

Profile and Settings

  • Name (Japanese)

    Kasai

  • Name (Kana)

    Hisae

  • Name

    201201071036543882

Alternate Names

Achievement

Research Interests

  • 魚病   魚類ウイルス   ゲノムワイド解析   免疫   インターフェロン   ワクチン   癌ウイルス   抗ウイルス   電解殺菌   紫外線殺菌   牡蠣   腸炎ビブリオ   ノロウイルス   浄化   

Research Areas

  • Life sciences / Aquaculture

Research Experience

  • 2024/06 - Today Hokkaido University Faculty of Fisheries Sciences Division of Marine Life Science

Awards

  • 2022/03 第59回獣医疫学会学術集会優秀発表賞
     養殖における魚病疫学解析の問題とその解決法－実験と 観察を繋ぐ為の数理モデルの活用－ 
    受賞者: 大森亮介;松山亮太;降幡充;笠井久会
  • 2016 Hokkaido A encouragement award of Science and Technology
     魚類増養殖ならびに漁獲物の衛生管理に資する海水殺菌法の確立 
    受賞者: Hisae Kasai
  • 2015 Japanese Society of Fisheries Science A research encouragement award of Fisheries Science
     魚類防疫による生産安定化と漁獲物の衛生管理に関する研究 
    受賞者: Hisae Kasai

Published Papers

  • Jun Nagata, Katsuki Takita, Hisae Kasai
    Aquaculture 741158 - 741158 0044-8486 2024/06 [Refereed]
  • Efficacy of egg disinfection by povidone-iodine solutions for inactivation of causative agent of bacterial kidney disease (Renibacterium salmoninarum) in vitro
    Jun Nagata, Sayo Morimoto, Makoto Ameno, Keito Yamaguchi, Ken-ichi Watanabe, Dominic K. Bagenda, Hisae Kasai
    Fish pathology 59 2024 [Refereed][Not invited]
  • 勝又義友, 勝又義友, 水野伸也, 永田淳, 笠井久会
    水産増殖 71 (4) 0371-4217 2023 [Refereed]
  • Rika Kudo, Ryota Yamano, Juanwen Yu, Shotaro Koike, Alfabetian Harjuno Condro Haditomo, Mayanne A M de Freitas, Jiro Tsuchiya, Sayaka Mino, Fabiano Thompson, Jesús L Romalde, Hisae Kasai, Yuichi Sakai, Tomoo Sawabe
    PloS one 18 (8) e0290060  2023 [Refereed]
     
    A Gram-staining-negative, oxidase-positive, strictly aerobic rod-shaped bacterium, designated strain PT1T, was isolated from the laboratory-reared larvae of the sea cucumber Apostichopus japonicus. A phylogenetic analysis based on the 16S rRNA gene nucleotide sequences revealed that PT1T was closely related to Neptuniibacter marinus ATR 1.1T (= CECT 8938T = DSM 100783T) and Neptuniibacter caesariensis MED92T (= CECT 7075T = CCUG 52065T) showing 98.2% and 98.1% sequence similarity, respectively. However, the average nucleotide identity (ANI) and in silico DNA-DNA hybridization (DDH) values among these three strains were 72.0%-74.8% and 18.3%-19.5% among related Neptuniibacter species, which were below 95% and 70%, respectively, confirming the novel status of PT1T. The average amino acid identity (AAI) values of PT1T showing 74-77% among those strains indicated PT1T is a new species in the genus Neptuniibacter. Based on the genome-based taxonomic approach, Neptuniibacter victor sp. nov. is proposed for PT1T. The type strain is PT1T (JCM 35563T = LMG 32868T).
  • Chunqi Jiang, Hisae Kasai, Sayaka Mino, Jesús L Romalde, Tomoo Sawabe
    Environmental microbiology 24 (10) 4587 - 4606 2022/09/15 [Refereed]
     
    The Splendidus clade is the largest clade in Vibrionaceae, and its members are often related to mortality of marine animals with huge economic losses. The molecular bases of their pathogenicity and virulence, however, remain largely unknown. In particular, the complete genome sequences of the Splendidus clade species are rarely registered, which is one of the obstacles to predict core and/or unique genes responsible to their adaptation and pathogenicity, and to perform a fine scale meta-transcriptome during bacterial infection to their hosts. In this study, we obtained the complete genomes of all type strains in the Splendidus clade and revealed that 1) different genome sizes (4.4-5.9 Mb) with V. lentus the biggest and most of them had several big plasmids, likely because of the different features on mobilome elements, 2) the Splendidus clade consists of 19 species except V. cortegadensis, and 3 sub-clades (SC) were defined with the 15 most closely related members as SC1; 3) different carbohydrate degradation preferences may be the result of environmental adaptation, 4) a broad prediction of virulence factors (VFs) revealed core and species unique VF genes. This article is protected by copyright. All rights reserved.
  • Ryosuke Omori, Ryota Matsuyama, Yukihiko Nakata, Mitsuru Furihata, Hisae Kasai
    Aquaculture 554 738165 - 738165 0044-8486 2022/05 [Refereed]
  • Yunato Kuroyanagi, Jiro Tsuchiya, Chunqi Jiang, Sayaka Mino, Hisae Kasai, Daisuke Motooka, Tetsuya Iida, Masataka Satomi, Tomoo Sawabe
    Frontiers in Marine Science 9 2022 [Refereed][Not invited]
     
    Light is one of the most critical stimuli in the majority of living organisms. In the last two decades, blue light (BL) has become a major subject of attention because of developments in light-emitting diodes (LED). The effects of BL on eukaryotic organisms and phototrophic prokaryotes have been well studied, but the knowledge of its effects on non-phototrophic prokaryotes remains unclear. Since BL can penetrate seawater, it is expected that most prokaryotes living in the ocean possess molecular mechanisms which protect against BL. The aim of this study is to assess the molecular mechanisms of Vibrio parahaemolyticus cells against BL as a marine bacterial model compared to other wavelength light exposures. Physiological and transcriptomic analyses of BL-exposed cells compared to other light treated cells revealed the highest ROS fold change, the highest number of differentially expressed genes (DEGs), and up-regulation in the gene responsible to not only compatible solute such as glycine betaine and ectoine but also iron-sulfur biosynthesis related to ROS formation. Furthermore, red light (RL) up-regulated the expression of cryptochrome DASH, a protein known to be excited by BL, and orange light (OL) decreased the expression of thermostable direct hemolysin (TDH), suggesting that OL attenuates the virulence of V. parahaemolyticus. In addition, the expression of VtrA (V. parahaemolyticus type III secretion system 2 (T3SS2) regulator A) but not VtrB (V. parahaemolyticus T3SS2 regulator B) increased under both light treatments, indicating that light exposure is unlikely to be involved in T3SS2-mediated pathogenicity. These results expand our knowledge on unique light responses in non-phototrophic marine prokaryotes.
  • Tanya Ju-Ngam, Nichanun McMillan, Mamoru Yoshimizu, Hisae Kasai, Ratree Wongpanya, Prapansak Srisapoome
    Biomolecules 11 (7) 2021/07/15 [Refereed]
     
    The aims of this research were to perform molecular characterization and biofunctional analyses of giant river prawn Hsp40 and Hsp90 genes (Mr-hsp40 and Mr-hsp90) under various stress conditions. Comparisons of the nucleotide and amino acid sequences of Mr-hsp40 and Mr-hsp90 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 Mr-hsp40 was highly expressed in the gills and testis, and Mr-hsp90 expression was observed in all tissues, with the highest expression in the ovary. The expression patterns of Mr-hsp40 and Mr-hsp90 transcripts under Aeromonas hydrophila challenge and heat-cold shock conditions were examined in gills, the hepatopancreas and hemocytes, at 0, 3, 6, 12, 24, 48 and 96 h by qRT-PCR. Under bacterial challenge, Mr-hsp40 displayed variable expression patterns in all tissues examined during the tested periods. In contrast, upregulated expression of Mr-hsp90 was quickly observed from 3 to 12 h in the gills and hepatopancreas, whereas obviously significant upregulation of Mr-hsp90 was observed in hemocytes at 12-96 h. Under temperature shock conditions, upregulation of Mr-hsp40 expression was detected in all tested tissues, while Mr-hsp90 expression was quickly upregulated at 3-48 h in all tissues in response to 35 °C conditions, and conditions of 35 and 25 °C stimulated its expression in gills and the hepatopancreas at 12 and 48 h, respectively. Silencing analyses of these two genes were successfully conducted under normal, high-temperature (35 °C) and A. hydrophila infection conditions. Overall, knockdown of Mr-hsp40 and Mr-hsp90 effectively induced more rapid and higher mortality than in the PBS control and GFP induction groups in temperature and infectious treatments. Evidence from this study clearly demonstrated the significant functional roles of Mr-hsp40 and Mr-hsp90, which are crucially involved in cellular stress responses to both temperature and pathogenic bacterial stimuli.
  • 笠井久会, 永田淳, 永田淳
    魚病研究 55 (4) 0388-788X 2021 [Invited]
  • Hisae Kasai, Katsutoshi Arai
    Bulletin of Fisheries Sciences, Hokkaido University 70 (2) 113 - 118 2020/12/23 [Not refereed]
  • Jun Nagata, Sayo Morimoto, Dominic K. Bagenda, Hisae Kasai
    Fisheries Science 86 (5) 829 - 834 0919-9268 2020/09/01 [Refereed]
     
    © 2020, Japanese Society of Fisheries Science. The distribution of salmon roe poses a risk to the salmon industry due to the potential transmission of quarantinable disease-causing pathogens. The curing of commercial salmon roe with saturated saline or soy sauce seasoning is widespread in Japan. The aim of this study was to evaluate the effect of commercial curing processes on quarantinable disease-causing pathogens [Aeromonas salmonicida, Renibacterium salmoninarum, Yersinia ruckeri, infectious hematopoietic necrosis virus (IHNV), infectious pancreatic necrosis virus (IPNV), Oncorhynchus masou virus (OMV)] of salmon. Curing with saturated saline for 8 min slightly decreased the viability of A. salmonicida, from 6.0 log colony-forming units (CFU)/ml to 5.1 log CFU/ml, but did not affect the viability of R. salmoninarum or Y. ruckeri. Curing with soy sauce seasoning for 90 min decreased the viability of A. salmonicida from 5.5 log CFU/ml to undetectable levels, but did not affect those of R. salmoninarum or Y. ruckeri. Neither saturated saline nor soy sauce seasoning affected the infectivity of IHNV, IPNV or OMV. In conclusion, the efficacy of curing was only demonstrated for A. salmonicida when soy seasoning was employed. This study shows that quarantine measures other than those examined here need to be developed for the safe distribution of salmon roe.
  • Akifumi Shiomi, Kohjiro Nagao, Hisae Kasai, Yuji Hara, Masato Umeda
    Bioscience, Biotechnology and Biochemistry 84 (3) 583 - 593 0916-8451 2020/03/03 [Refereed][Not invited]
     
    © 2019, © 2019 Japan Society for Bioscience, Biotechnology, and Agrochemistry. Fish cell lines are widely used for the studies of developmental biology, virology, biology of aging, and nutrition physiology. However, little is known about their physicochemical properties. Here, we report the phospholipid compositions and mechanical properties of cell membranes derived from freshwater, anadromous and marine fish species. Biophysical analyses revealed that fish cell lines have highly deformable cell membranes with significantly low membrane tensions and Young’s moduli compared with those of mammalian cell lines. The induction of cellular senescence by DNA demethylation using 5-Aza-2ʹ-deoxycytidine significantly reduced the deformability of fish cell membrane, but hydrogen peroxide-induced oxidative stress did not affect the deformability. Mass spectrometry analysis of phospholipids revealed that the level of phosphatidylethanolamine molecules containing polyunsaturated fatty acids significantly increased during the 5-Aza-2ʹ-deoxycytidine-induced cellular senescence. Fish cell lines provide a useful model system for studying the changes in the physicochemical properties of cell membranes during cellular senescence. Abbreviations: 2D-TLC: two-dimensional thin layer chromatography; 5-Aza-dC: 5-Aza-2ʹ-deoxycytidine; DHA: docosahexaenoic acid; EPA: eicosapentaenoic acid; FBS: fetal bovine serum; PC: phosphatidylcholine; PE: phosphatidylethanolamine; PI: phosphatidylinositol; PS: phosphatidylserine; PUFA: polyunsaturated fatty acid; SA-β-gal: senescence-associated beta-galactosidase; SM: sphingomyelin.
  • M. Y. Ina-Salwany, Nurhidayu Al-saari, Aslah Mohamad, Fathin Amirah Mursidi, Aslizah Mohd-Aris, M. N.A. Amal, Hisae Kasai, Sayaka Mino, Tomoo Sawabe, M. Zamri-Saad
    Journal of Aquatic Animal Health 31 (1) 3 - 22 0899-7659 2019/03 [Refereed][Not invited]
     
    © 2018 American Fisheries Society Current growth in aquaculture production is parallel with the increasing number of disease outbreaks, which negatively affect the production, profitability, and sustainability of the global aquaculture industry. Vibriosis is among the most common diseases leading to massive mortality of cultured shrimp, fish, and shellfish in Asia. High incidence of vibriosis can occur in hatchery and grow-out facilities, but juveniles are more susceptible to the disease. Various factors, particularly the source of fish, environmental factors (including water quality and farm management), and the virulence factors of Vibrio, influence the occurrence of the disease. Affected fish show weariness, with necrosis of skin and appendages, leading to body malformation, slow growth, internal organ liquefaction, blindness, muscle opacity, and mortality. A combination of control measures, particularly a disease-free source of fish, biosecurity of the farm, improved water quality, and other preventive measures (e.g., vaccination) might be able to control the infection. Although some control measures are expensive and less practical, vaccination is effective, relatively cheap, and easily implemented. In this review, the latest knowledge on the pathogenesis and control of vibriosis, including vaccination, is discussed.
  • Dominic K. Bagenda, Shotaro Nishikawa, Hiroki Kita, Yu Kinai, Shima Terai, Motoichi Kato, Hisae Kasai
    Aquaculture 500 135 - 140 0044-8486 2019/02/01 [Refereed][Not invited]
     
    © 2018 Feeding regimes of laboratory-cultured algae reportedly maintain meat quality as well as reduce mortality of oysters during prolonged depuration. However, feeding regimes are costly and their impact on depuration efficacy is not understood. The impact of a feeding regime of laboratory-cultured Chaetoceros gracilis (added at a manufacturer-recommended dose of 1.4 × 109 cells/oyster/day) on depuration efficacy for batches of Pacific oysters collected from four sites in Japan in 2016 and 2017 was evaluated. Depuration was done in filtered seawater (FSW) under conditions of low temperature and high salinity (17 °C and 28 to 31 ppt respectively). Indicators of depuration efficacy (Vibrio parahaemolyticus and V. vulnificus counts, condition index as well as mortality) for oyster batches that were fed were compared with those for batches that were not fed over a depuration period of 14 days. Generally, feeding did not significantly affect removal of V. parahaemolyticus and V. vulnificus, condition index or mortality of oysters (P >.05). However, for one batch of oysters in an exceptionally poor physiological state (condition index <32), condition index improved significantly after 14 days of depuration with feeding. From the results it was concluded that under conditions of low temperature and high salinity, feeding does not have a significant impact on depuration efficacy unless initial condition index of the batch was very low. This is the first study to show that maintaining high salinity and low temperature during oyster depuration eliminates the need for feeding regimes.
  • Shotaro Nishikawa, Tetsuo Nakano, Hisae Kasai
    Aquaculture Science 水産増殖談話会 67 (1) 25 - 32 0371-4217 2019 [Refereed][Not invited]
     
    © 2019 Japanese Society for Aquaculture Research, Nishimura Toushadou Ltd.. All rights reserved. Polyinosinic-polycytidylic acid (PIC), a synthetic double-stranded RNA, is a strong innate immune response inducer. Although it is an innate immune inducer, when administered to some fish species at low temperatures, PIC may be toxic and mortality may occur. Moreover, in mice, immunoreactivity is affected by nucleotide length of PIC. The aim of this study was to demonstrate the effects of body size, water temperature and length of PIC on tolerance and immunoreactivity of rainbow trout to PIC. Tolerance of fish to PIC was better for large fish (145 g) than for small fish (12 g). Furthermore, PIC-induced Mx gene expression when water temperature was high peaked at day 1 and then decreased sharply. When water temperature was low, Mx gene expression lasted longer and high mortality indicated toxicity of PIC. Observations on the effects of length of PIC revealed that Mx gene expression was not significantly related to the length of PIC.
  • 小原 昌和, 野村 哲一, 笠井 久会, 吉水 守
    Fish Pathology 日本魚病学会 53 (2) 90 - 93 0388-788X 2018 [Not refereed][Not invited]
     
    <p>吸水過程において卵門から細菌性冷水病や細菌性腎臓病の病原細菌が卵内へ侵入する卵内感染の機序を明らかにするため，SEMを使用して，ニジマスの未受精卵，吸水卵および人為的な病原菌汚染卵における卵門および卵膜の形態を観察した。排卵された未受精卵の卵膜表面では，卵門を除き細菌が卵内に侵入する可能性のある小孔状の形態はみられなかった。卵門管の上部および管底の口径は細菌が十分に通過できるほどに大きく，吸水に伴って管内の閉塞が進む時期は実験的に卵内感染が成立した時期と一致することが確かめられた。</p>
  • Koji Yamazaki, Kantaro Takeuchi, Yohei Yamazaki, Sayaka Mino, Hisae Kasai, Toko Sawabe, Tomoo Sawabe, Masataka Satomi
    Nippon Shokuhin Kagaku Kogaku Kaishi 日本食品科学工学会 65 (4) 197 - 204 1341-027X 2018 [Not refereed][Not invited]
     
    Copyright© 2018, Japanese Society for Food Science and Technology. The control of food poisoning associated with fish and fish products is challenging, even in the developed world. Injured cells of bacterial pathogens, generated by various stressors during food processing, are considered to be an important risk factor in food poisoning incidents. It is important to accumulate more knowledge on the physiology, genetics, and molecular biology of injured bacterial cells related to fish and fish products, and also to apply this knowledge to the development of new technologies. Here, we introduce recent advances in the physiology and genetics of Vibrio parahaemolyticus and Listeria monocytogenes and discuss future directions of the risk control of pathogens in fisheries. （Accepted Nov. 17, 2017）.
  • Keisuke Ikemoto, Mamoru Yoshimizu, Mitsuru Furihata, Masakazu Kohara, Hisae Kasai
    Fish Pathology 日本魚病学会 51 (2) 60 - 63 0388-788X 2016 [Refereed][Not invited]
     
    © 2016 The Japanese Society of Fish Pathology. Pathogenicity of a rainbow trout isolate RtNa- 0010 of Oncorhynchus masou virus (OMV = salmonid herpesvirus 2) was investigated in salmonids and cyprinids. Immersion method was used to challenge three species of salmonid fish with RtNa-0010 and OMV reference strain OO-7812 at a dose of 100 TCID50/mL for 60 min. Cumulative mortality of rainbow trout was 3 and 51 of 51 fish when challenged with OO-7812 and RtNa-0010 respectively. When six salmonids and three cyprinids were challenged with RtNa-0010 (103 TCID50/fish) by intraperitoneal injection, mortality rates were 85%, 10% and 0% for rainbow trout, whitefish Coregonus lavaretus maraena and other tested fish respectively.
  • Ito Shingo, Kasai Hisae
    Aquaculture Science 水産増殖談話会 63 (3) 255 - 259 0371-4217 2015 [Refereed][Not invited]
     
    We observed mortality due to scuticociliate infection in barfin flounder and subsequently identified the causative pathogen and examined its pathogenicity. In addition, we examined the sensitivity of a pathogen isolate and the tolerance of the barfin flounder to vinegar solutions and tea extract solutions to identify scuticociliate infection control measures in this fish species. Species identification of the causative agent was performed using polymerase chain reaction (PCR); the causative agent was identified as Miamiensis avidus. M. avidus was administered to barfin flounder via immersion or intraperitoneal injection. In the intraperitoneal injection experiments, the cumulative mortality rate within one week was 100% at a dose of 105 ciliates/fish. In contrast, immersion challenge experiments were unsuccessful. M. avidus survival fell below the detection limit after exposure to a 0.7% vinegar solution or a 0.01% tea extract solution for 30 min. Exposure to a 0.03% tea extract solution for 1h was toxic to the barfin flounder, whereas exposure to a 0.7% vinegar solution for 1h exhibited low toxicity. In conclusion, we suggest that exposure to a 0.7% vinegar solution for 30 min is an effective M. avidus infection treatment and control method in vitro.
  • Devon Ronald Dublín, Mamoru Yoshimizu, Hisae Kasai
    Revista Electronica de Veterinaria Veterinaria Organización 15 (6) 1 - 11 1695-7504 2014/06/01 [Refereed][Not invited]
     
    The success of the methods employed in the detection of Aeromonas salmonicida depends on several factors including detection limits which are not always considered when planning a diagnostic protocol. First, detection limits of A. salmonicida by Coomassie Brilliant Blue Agar (CBBA) culture, Immuno-Fluorescence Antibody Test (IFAT), Coagglutination test (CoAgT) and Polymerase Chain Reaction (PCR) were analyzed, then a controlled wet-lab experiment was conducted using 60 masu salmon (Oncorhynchus masou) fry inoculated with A. salmonicida and based on the results obtained, an epizootiological survey of selected rivers in Hokkaido was then conducted. Detection limits were 102 for CBBA, 104 for the IFAT, 105 for PCR and 103 for the CoAgT from an original de A. salmonicida broth culture of 1.3 x 108 CFU/mL demonstrating that CBBA and the CoAgT were better at detecting the bacteria at low concentrations. The wet-lab analysis produced results of detection limits of a similar trend, with CBBA, IFAT, PCR and CoAgT at 10-3 , 10-3, 10-1 and 10-3 from kidney samples of 9.9 X 104 CFU/g respectively. The results from the epizootiological survey in Hokkaido showed positive from CBBA with IFAT, CoAgT and PCR corroborating them in varying degrees thus demonstrating the importance of a multi-diagnostic approach in scenarios of this nature.
  • YOSHIMIZU Mamoru, KASAI Hisae, WATANABE Kenichi
    Journal of Intestinal Microbiology 公益財団法人 日本ビフィズス菌センター 28 (1) 7 - 14 1343-0882 2014 [Refereed][Not invited]
     
    Generally, normal bacterial microbiota play an important role in inhibiting the growth of pathogenic bacteria in the intestine or on the skin, and stimulate the immune responses of host animals. In aquaculture, mortalities of larvae and fry of cultured fish due to viral diseases remain a major problem for regular food production. Although vaccines can be useful to control viral diseases, because of a immature immune system, they are not effective during the early stages of larval growth. Therefore alternative strategies to control viral diseases are required for sustainable aquaculture and seed production. We investigated fish pathogenic viruses in an aquatic environment in order to understand their survival and interactional relationships with bacteria for the prevention of fish viral diseases in aquaculture. In a series of studies of the microbial ecosystem, we found that many bacteriaproducing antiviral substances could be isolated from aquatic environments, such as hatchery water supply, river mouth water, beach water, and intestinal contents of aquatic animals. Intestinal bacteria, such as Aeromonas spp. and Vibrio spp. producing anti-viral substances were isolated from intestinal contents of masu salmon (Oncorhynchus masou), Japanese flounder (Paralichthys olivaceus), barfin flounder (Verasper moseri) and Pacific oyster (Crassostrea gigas). Aeromonas strains produced anti-infectious hematopoietic necrosis (IHNV; Novirhabdovirus) substances, and Vibrio strains showed anti-IHNV, salmonid herpesvirus Oncorhynchus masou virus (OMV; Salmonivirus), hirame rhabdovirus (HIRRV), barfin flounder nervous necrosis virus (BF-NNV; Nodavirus) and feline calicivirus (FCV) activities. When A. hydrophila strains M-26 and M-38 were mixed with food pellets and fed to rainbow trout (O. mykiss) and masu salmon, both bacteria became dominant in the intestinal microbiota and anti-IHNV activity was observed in homogenates of intestinal contents. These rainbow trout and masu salmon fed the Aeromonas spp. showed more resistance to artificial IHNV challenge tests. Barfin flounder fed Vibrio spp. strains 2IF6 with Altemia sp. showed anti-IHNV, OMV, HIRRV and BF-NNV activities in their intestinal contents. Larvae fed the Vibrio spp. showed a higher survival rate than the control fish. In the case of Japanese flounder larvae fed with V. alginolyticus strain V-23 manipulated rotifer showed anti-OMV (FHV; flounder herpesvirus surrogate) activities in the intestinal contents and rearing water in the tank. Furthermore, V. neptunis strain V-176 and Vibrio sp. Strain V-4 isolated from intestinal contents of Pacific oyster showed anti-feline calicivirus (FCV; Norovirus surrogate) and OMV (Ostreid herpesvirus-1 microvariant (OsHV-1 μVar) surrogate) activities. Norovirus and OsHV-1μVar will hopefully be inactivated in the intestines of oysters fed V. neptunis V-176 or Vibrio sp. V-4 with Chaetoceros gracilis, respectively. These results show that, by manipulating diets with anti-viral substance-producing bacteria, the resistance of fish or shellfish larvae to viral disease can be improved thereby helping to ensure regular food production through aquaculture.
  • N. Yoshida, R. K. Sasaki, H. Kasai, M. Yoshimizu
    Journal of Fish Diseases 36 (12) 997 - 1005 0140-7775 2013/12 [Refereed][Not invited]
     
    Since its first outbreak in Japan in 2003, koi-herpesvirus (KHV) remains a challenge to the carp Cyprinus carpio L. breeding industry. In this study, inactivation of KHV in water from carp habitats (carp habitat water) was investigated with the aim of developing a model for rapidly inactivating the pathogen in aquaculture effluent. Experiments with live fish showed that, in carp habitat water, KHV lost its infectivity within 3 days. Indications were that inactivation of KHV was caused by the antagonistic activity of bacteria (anti-KHV bacteria) in the water from carp habitats. Carp habitat water and the intestinal contents of carp were therefore screened for anti-KHV bacteria. Of 581 bacterial isolates, 23 showed anti-KHV activity. An effluent treatment model for the disinfection of KHV in aquaculture effluent water using anti-KHV bacteria was developed and evaluated. The model showed a decrease in cumulative mortality and in the number of KHV genome copies in kidney tissue of fish injected with treated effluent compared with a positive control. It is thought that anti-KHV bacteria isolated from the intestinal contents of carp and from carp habitat water can be used to control KHV outbreaks. © 2013 John Wiley & Sons Ltd.
  • Masako Yokoo, Ryosuke Fujita, Yumiko Nakajima, Mamoru Yoshimizu, Hisae Kasai, Shin ichiro Asano, Hisanori Bando
    Biochemical and Biophysical Research Communications 439 (1) 18 - 22 0006-291X 2013/09/13 [Refereed][Not invited]
     
    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. The infectivity of the recombinant virus to fish cells was assessed by monitoring the expression of a fluorescent protein encoded in the viral genome. We detected transgene expression in CHSE-214, HINAE, and EPC cells, but not in GF or RTG-2 cells. In the co-infection assay of the Mos1-expressing virus and reporter gene-expressing virus, we successfully transformed CHSE-214 and HINAE cells. These results suggest that the combination of a baculovirus and Mos1 transposable element may be a tool for transgenesis in fish cells. © 2013 Elsevier Inc.
  • Masakazu Kohara, Hisae Kasai, Mamoru Yoshimizu
    Fish Pathology 日本魚病学会 48 (3) 97 - 100 0388-788X 2013 [Refereed][Not invited]
     
    In this study, rainbow trout Oncorhynchus mykiss and amago salmon O. masou were used to study intra-ovum infection with Flavobacterium psychrophilum and Renibacterium salmoninarum, respectively. To investigate the possibility of intra-ovum infection of eggs in the coelomic cavity, the contamination of coelomic fluid and egg contents from ripe females were examined. The ranges of viable counts of F. psychrophilum and R. salmoninarum in coelomic fluid were 1010" 42 and io16" 99 CFU/mL, respectively. However, neither F. psychrophilum nor R. salmoninarum was isolated from the egg contents. It was concluded that there was little possibility of intra-ovum infection of salmonid eaas in the coelomic cavity.
  • Matthura Labaiden, Hisae Kasai, Mamoru Yoshimizu, Sataporn Direkbusrakom
    Walailak Journal of Science and Technology 10 (6) 601 - 606 1686-3933 2013 [Refereed][Not invited]
     
    Sodium bicarbonate is a disinfectant that can be used in food processing because it is safe for humans and is cost effective. In this study, sodium bicarbonate was used to eliminate E. coli from oysters (Crassostrea belcheri). The experiments were divided into 3 trials; in vitro disinfection of E. coli using sodium bicarbonate and the toxicity of sodium bicarbonate in oysters were determined in the first and second trials, and the effectiveness of sodium bicarbonate in eliminating E. coli in naturally contaminated oysters was performed in the final trial. From the in vitro study, it was found that sodium bicarbonate at 10 and 100 mM could inhibit E. coli; however, the high dose of 100 mM is not suitable to use on oysters, since the 50 % lethal concentration of sodium bicarbonate for oysters was 63 mM. An application of sodium bicarbonate to eliminate E. coli in naturally contaminated oysters at 10 mM for 1 h could decrease the E. coli to 96 MPN/100 g, lower than the standard level (230 MPN/100 g) after depuration. These results suggest that sodium bicarbonate could be potentially used to eliminate E. coli contamination in oysters.
  • Masakazu Kohara, Hisae Kasai, Mamoru Yoshimizu
    Fish Pathology 日本魚病学会 47 (2) 49 - 55 0388-788X 2012 [Refereed][Not invited]
     
    Intra-ovum infection of artificially contaminated salmonid (rainbow trout or amago salmon) eggs was studied using three fish pathogens (Flavobacterium psychrophilum, Renibacterium salmoninarum and Aeromonas salmonicida). Artificial contamination was performed using egg-surface contamination or immersion-water contamination. For F. psychrophilum and R. salmoninarum, infection occurred by the entry of pathogens from the egg surface to the perivitelline space through the micropyle during water-hardening. The infection rate was higher for egg-surface contamination than for immersionwater contamination. The successful concentration of F. psychrophilum for the occurrence of intraovum infection was 107 CFU/mL or more for egg surface contamination, and was 10 9 CFU/mL or more for immersion-water contamination. After the entry into eggs, F. psychrophilum increased to 107 CFU/egg but A. salmonicida steadily decreased and became undetectable. © 2012 The Japanese Society of Fish Pathology.
  • Hisae Kasai, Koji Kawana, Matthura Labaiden, Kenji Namba, Mamoru Yoshimizu
    Aquaculture 319 (3-4) 315 - 318 0044-8486 2011/10/01 [Refereed][Not invited]
     
    Electrolyzed seawater (ESW) is reportedly an effective disinfectant for aquaculture equipment because of its simple mechanism and cost effectiveness. The potential of electrolyzed seawater for oyster depuration was studied using different experiments. The first was determination of chlorine tolerance of oysters. Second was effectiveness of ESW against Escherichia coli in artificially contaminated oysters and third was effectiveness of ESW against E. coli in naturally contaminated oysters from two culture farms. Tolerance of oysters for Chlorine was studied by scanning electron microscopy (SEM) and histological observation demonstrating that more than 0.5. mg/L of chlorine was toxic while 0.2. mg/L was safe for the oysters. Oysters artificially contaminated with E. coli (230 MPN/100 mL, 16.5. °C for 15 h) were depurated for 6, 24, and 48 h using ESW and UV irradiated seawater. E. coli counts in artificially contaminated oysters decreased to below the detection limit (30 E. coli MPN/100 g) after depuration with ESW for 24 h or UV irradiated seawater for 6 h. In experiments on naturally contaminated oysters E. coli counts decreased to below detection limits after depuration with ESW for 24 h. From these results, electrolysis of seawater is a useful method for post harvest elimination of E. coli from oysters. © 2011 Elsevier B.V.
  • Jun Yokoyama, Hisae Kasai, Atsumi Furuya, Mamoru Yoshimizu
    Nippon Suisan Gakkaishi (Japanese Edition) 日本水産學會 77 (3) 409 - 415 0021-5392 2011 [Refereed][Not invited]
     
    To control the hygienic conditions of fishery products from catching to landing and processing, both qualitative and quantitative bacterial observations at fishing ports must be considered. Thirty-six fishing ports in Hokkaido, northern Japan, were selected and the distributions of coli form bacteria were studied at these sites. Coli forms were observed from all fishing ports, and Escherichia coli were observed from 30 fishing ports. Especially, in relation to the number of coli form bacteria and E. coli, fishing ports which are located near a river show higher levels than any other fishing ports.
  • Natsuko Yoshida, Kazuaki Ishida, Hisae Kasai, Mamoru Yoshimizu
    Nippon Suisan Gakkaishi (Japanese Edition) 日本水産學會 77 (1) 94 - 96 0021-5392 2011 [Refereed][Not invited]
     
    水産廃棄物であるヒトデの有効利用を目的に，魚類飼育排水処理施設由来細菌のヒトデ成型骨片への付着性を検討した。5 回洗浄を行った後でも，ヒトデ成型骨片の生菌数は 108 CFU/g 程度であった。また，ヒトデ成型骨片と市販ろ材への細菌の付着量を比較したところ，どのろ材も洗浄後の生菌数は 107 CFU/g 程度であった。以上の結果から，ヒトデ成型骨片は市販ろ材と同様に細菌付着用のろ材として使用できることが明らかとなった。
  • KOHARA Masakazu, OGAWA Shigeru, KASAI Hisae, YOSHIMIZU Mamoru
    Aquaculture Science 水産増殖談話会 58 (1) 37 - 43 0371-4217 2010/03/20 [Refereed][Not invited]
     
    Egg-washing with isotonic solution has been used to improve the artificial fertilization in fresh-water salmon aquaculture.Usually, unfertilized eggs are rinsed twice or three times with isotonic solution and showered before fertilization. We investigated the effect of egg-washing using rainbow trout eggs on elimination of some causative agents of cold water disease (Flavobacterium psychrophilum), flunculosis (Aeromonas salmonicida), infectious hematopoietic necrosis (IHNV) and Oncorhynchus masou virus disease (OMV), quantitatively and on prevention of intra-ovum infection with F. psychrophilum. The number of live bacterial cells or virus infectivity titers which were eliminated by egg-washing, was 103CFU/ml in F. psychrophilum, 105CFU/ml in A. salmonicida, or 104TCID50/ml in both of IHNV and OMV. In shower washing, the eliminated extent of F. psychrophilum or A. salmonicida cells increased with increasing isotonic solution volume. The ratio of intra-ovum infection with F. psychrophilum was clearly less in rinsed eggs than in non-treated eggs, and result of detection from showered eggs was negative. These results suggest that egg-washing with isotonic solution is very effective to eliminate the bacteria or viruses on egg surface and is able to decrease the risk of intra-ovum infection.
  • Jun Yokoyama, Hisae Kasai, Satomi Mori, Hiroshi Hayashi, Mamoru Yoshimizu
    Nippon Suisan Gakkaishi (Japanese Edition) 日本水産學會 76 (1) 62 - 67 0021-5392 2010 [Refereed][Not invited]
     
    To control the hygienic conditions of fishery products from catching to landing and processing, both qualitative and quantitative bacterial observations at fishing ports must be considered. Four fishing ports, Shibetsu and Rausu in Hokkaido, Yui in Shizuoka prefecture, and Hakata in Fukuoka prefecture, were selected and the distribution of coliform bacteria and human pathogenic vibrio species were studied at these sites. Coliforms and Escherichia coli were observed from all four fishing ports, while Vibrio parahaemolyticus was observed from Yui and Hakata fishing ports. The number of V. pare haemolyticus in the surface seawater varied seasonally from <1.8 to 240 MPN/100 mL. E. coli and human pathogenic vibrio species were not observed from electrolyzed, chlorine disinfected or deep seawater used at these four fishing ports for hygiene control. The disinfected seawater or deep seawater for hygiene control was effective for washing off the bacteria from floors and equipment at the fishing markets.
  • Mamiko Mochizuki, Hyoung Jun Kim, Hisae Kasai, Toyohiko Nishizawa, Mamoru Yoshimizu
    Fish Pathology 日本魚病学会 44 (4) 159 - 165 0388-788X 2009/12 [Refereed][Not invited]
     
    Infectious hematopoietic necrosis virus (IHNV) is the causative agent of IHN, one of the most serious viral diseases of salmonid fish. A total of five major genogroups including JRt for Asian isolates were confirmed among worldwide isolates based on glycoprotein (G) gene nucleotide (nt) sequences. The present study revealed existence of new two lineages, JRt Shizuoka and JRt Nagano, in the genogroup JRt by addition of new isolates obtained in 2006. The maximum nt diversity of G gene within JRt Shizuoka or JRt Nagano lineage was 6.3% or 3.5%, while that between JRt Shizuoka and JRt Nagano lineages was 7.0%. To evaluate influence of the evolutional divergence to virulence of IHNV, experimental challenges to rainbow trout Oncorhynchus mykiss were conducted by bath exposure at 104 TCIDjo/mL of RtShizO6s and RtShizO6a (JRt Shizuoka lineage), RtNag96 and RtNagO6a (JRt Nagano lineage), and ChAb76 (a representative of the genogroup U). Distinct difference was observed in IHNV virulence to rainbow trout, i.e. the highest virulence was in RtShiz06s and RtShiz06a (≥ 76% of mortalities), and subsequently in RtNag96 and RtNag06a (20-40%), but scarcely any virulence in ChAb76 (≤ 10%). Thus it was suggested that nt diversity of Japanese IHNV continued rapidly with changing its virulence in rainbow trout farm environments.
  • Hisae Kasai, Shuhei Iwawaki, Mamoru Yoshimizu
    Fish Pathology 日本魚病学会 44 (4) 182 - 184 0388-788X 2009/12 [Refereed][Not invited]
     
    Infectious salmon anemia (ISA) is a virus disease of Atlantic salmon Salmo salar in Europe and the Americas, but it has not been isolated in Far East Asia. In this study, we conducted virus isolation with ASK and ASE cells targeting ISA virus (ISAV) from a total of 5,967 fish belonging to eight salmonid species in Japan from 2005 to 2007. ISAV was not isolated from any fish examined but infectious hematopoietic necrosis virus was isolated from 116 fish belonging to three species, while infectious pancreatic necrosis virus was found in 14 fish from three species. It was considered that Japan is still free from ISAV.
  • Noriko Urushibara, Shinya Mitsuhashi, Tomoyuki Sasaki, Hisae Kasai, Mamoru Yoshimizu, Hiroyoshi Fujita, Atsushi Oda
    Comparative Biochemistry and Physiology - C Toxicology and Pharmacology 149 (4) 468 - 475 1532-0456 2009/05 [Refereed][Not invited]
     
    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. TBT treatment resulted in significant caspase activation, characteristic morphological changes, DNA fragmentation, and consequent apoptotic cell death in RTG-2 cells. TBT exposure induced the rapid and sustained accumulation of phosphorylated MAPKs, including extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK), and p38 MAP kinase (p38 MAPK). Further analysis using pharmacological inhibitors against caspases and MAPKs showed that TBT also induced cell death in a caspase-independent manner and that p38 MAPK is involved in TBT-induced caspase-independent cell death, whereas JNK is involved in the caspase-dependent apoptotic pathway. Thus, TBT employs at least two independent signaling cascades to mediate cell death in RTG-2 cells. To our knowledge, this is the first study revealing the relationship between MAPK activation and TBT cytotoxicity in RTG-2 cells. © 2008 Elsevier Inc. All rights reserved.
  • Aya Matsuo, Hiroyuki Oshiumi, Tadayuki Tsujita, Hiroshi Mitani, Hisae Kasai, Mamoru Yoshimizu, Misako Matsumoto, Tsukasa Seya
    Journal of Immunology 181 (5) 3474 - 3485 0022-1767 2008/09/01 [Refereed][Not invited]
     
    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. On poly(I:C)-stimulated fish cells, both recruit fgTICAM-1, which in turn moves from the TLR to a cytoplasmic signalosome region. Thus, fgTICAM-1 acts as a shuttling platform for IFN signaling. When fish cells expressing fgTLR22 are exposed to dsRNA or aquatic dsRNA viruses, cells induce IFN responses to acquire resistance to virus infection. Thus, fish have a novel TICAM-1-coupling TLR that is distinct from the mammalian TLR3 in cellular localization, ligand selection, and tissue distribution. TLR22 may be a functional substitute of human cell-surface TLR3 and serve as a surveillant for infection with dsRNA virus to alert the immune system for antiviral protection in fish. Copyright © 2008 by The American Association of Immunologists, Inc.
  • Tomoko Shimizu, Natsuko Yoshida, Hisae Kasai, Mamoru Yoshimizu
    Fish Pathology 日本魚病学会 41 (4) 153 - 157 0388-788X 2006/12 [Refereed][Not invited]
     
    The survivability of koi herpesvirus (KHV) in environmental water and sediment was evaluated using CCB cells. Samples were collected from Ibaraki prefecture, Kanagawa prefecture and Hakodate, Hokkaido. Significant reduction in the infectious titer of KHV was observed within 3 days in intact environmental water or sediment. However, KHV infectivity remained for more than 7 days in autoclaved or filtered (0.45 μm) water. In the autoclaved water containing sediment, KHV infectivity dropped below detectable limits within 7 days after inoculation. Ten of the 147 bacterial strains from rivers in Kanagawa, and two of the 62 bacterial strains from water from, Hakodate showed anti-KHV properties. The results suggest that in the absence of hosts, KHV can be rapidly inactivated in environmental water. © 2006 The Japanese Society of Fish Pathology.
  • Minoru Kimura, Kanako Mikami, Hiroshi Hoshikawa, Tatsunari Mori, Hisae Kasai, Mamoru Yoshimizu
    Nippon Suisan Gakkaishi (Japanese Edition) 日本水産學會 72 (1) 1 - 5 0021-5392 2006/01 [Refereed][Not invited]
     
    A study was carried out in order to reduce the hygienic bacteria from sea urchin Strongylocentrotus nudus viscera. The effect of pre-culturing before shipment using electrolyzed seawater on reduction of Vibrio parahaemolyticus and viable bacteria inhabiting the sea urchin viscera was examined. When 3% salt water suspended with V. parahaemolyticus was electrolyzed, the viable number of V. parahaemolyticus was reduced by more than 99.99% after treatment with 0.23 mg/L chlorine for one minute. In the case of sea urchin reared with electrolyzed seawater containing 0.76 mg/L chlorine for 2 days, a lot of dejecture was discharged, and the bacteria in the sea urchin viscera were reduced by more than 90%.
  • SHIMIZU Tomoko, SHINOZAKI Daisuke, KASAI Hisae, SAWABE Tomoo, WATANABE Kenichi, YOSHIMIZU Mamoru
    Aquaculture Science 水産増殖談話会 53 (3) 275 - 278 0371-4217 2005/09/20 [Refereed][Not invited]
     
    Effect of manipulation of dietary rotifer Brachionus plicatilis bacterial flora on the intestinal bacterial flora of Japanese flounder Paralichthys olivaceus larvae was investigated. Manipulation was done by disinfecting rotifer eggs to reduce viable bacterial counts and then by inoculating hatched rotifers with non-sucrose fermenting Vibrio splendidus strain V-15 to make the bacterium dominant in the rotifers. Flounder larvae were fed the manipulated rotifers and intestinal bacterial flora of the fish was monitored. The dominant intestinal bacterial flora of the flounder became Vibrio spp. These results indicate that intestinal bacterial flora of flounder can be artificially controlled by manipulating bacterial flora in diets.
  • Hisae Kasai, Yoshifumi Muto, Mamoru Yoshimizu
    Fish Pathology 日本魚病学会 40 (3) 137 - 138 0388-788X 2005/09 [Refereed][Not invited]
     
    The virucidal effects of ultraviolet (UV) irradiation, heat treatment and disinfectants against koi herpesvirus (KHV) were evaluated using KF-1 cells. KHV (KHV-I strain) was completely inactivated by UV irradiation at a dose of 4.0 × 103 μ Ws/cm2 or heating to temperatures above 50°C for 1 min. KHV was completely inactivated by 200 mg/L iodophor, 60 mg/L benzalkonium chloride solution or 30% ethyl alcohol for 20 min. When chlorine concentration was measured after mixing with virus supernatant containing medium and fetal bovine serum, 97.5% and 98.5% reduction in infectivity was observed at 0.30 mg/L of chlorine for 30 s and 20 min, respectively. In practice, a tenfold concentration of chlorine (i.e. 3 mg/L) will be recommended to inactivate KHV completely. © 2005 The Japanese Society of Fish Pathology.
  • Kenichiro Kobayashi, Jacob A. Wani, Hisae Kasai, Toyohiko Nishizawa, Mamoru Yoshimizu
    Fish Pathology 日本魚病学会 40 (1) 29 - 31 0388-788X 2005/03 [Refereed][Not invited]
     
    A total 645 wild marine fish of 40 species were collected at the north (Wakkanai and Haboro), south (Hakodate) and east (Akkeshi) coasts of Hokkaido from 2000 to 2004 to conduct surveillance of fish viruses. Four fish cell lines (RTG-2, EPC, CHSE-214, FHM) were used for virus isolation from the brain, kidney and spleen of fish. Aquabirnavirus, which was identified as yellowtail ascites virus by a neutralization test, was isolated only from ten fish of four species caught at Akkeshi coastal area in 2002. These species were saffron cod Eleginus gracilis, snowy sculpin Myoxocephalus blandti, Japanese dace Tribolodon hakonensis and rainbow smelt Osmerus eperlanus mordax. Other viruses including viral hemorrhagic septicemia virus were not isolated. © 2005 The Japanese Society of Fish Pathology.
  • Yoshimizu Mamoru, Yoshinaka Toko, Hatori Shuichi, Kasai Hisae
    Bulletin of Fisheries Research Agency 水産総合研究センター (0) 47 - 54 1346-9894 2005/03 [Not refereed][Not invited]
     
    Special Issue: International Symposium on Koi Herpesvirus Disease : Strategy for Koi Herpesvirus Disease Control. 13 March 2004. Yokohama, Japan.
  • 笠井 久会, 野村 哲一, 吉水 守
    魚と卵 : さけ・ます資源管理センター技術情報 さけ・ます資源管理センター 170 (170) 1 - 8 2004/03 [Not refereed][Not invited]
  • Hisae Kasai, Emi Sugiyama, Mamoru Yoshimizu
    Nippon Suisan Gakkaishi (Japanese Edition) 日本水産學會 70 (1) 60 - 65+98 0021-5392 2004/01 [Refereed][Not invited]
     
    To control hygienic conditions at fishing ports, qualitative and quantitative bacterial observations have to be considered. In the fishing port located at Shibetsu town, Hokkaido, where the hazard analysis and critical control point (HACCP) system is performed, the distribution and composition of heterotrophic bacterial flora and coliform bacteria were studied in this hygienically controlled site. There was a little difference in the quality of water collected from inside and outside of the harbor. The number of viable bacteria in the surface seawater varied seasonally from 102 to 104 CFU/mL. The generic composition of bacteria collected from back part of the harbor, entrance of the harbor, and the front of the fish market was compared. The generic composition of the bacterial flora included the genera Pseudomonas, Alteromonas and Vibrio, which were observed through the year. Moraxella and gram-positive bacteria were also isolated in front of the fish market. Coliform were isolated inside and outside of the harbor throughout the year, and their counts increased as water temperature increased.
  • Hisae Kasai, Mamoru Yoshimizu
    Nippon Suisan Gakkaishi (Japanese Edition) 日本水産學會 69 (6) 955 - 959 0021-5392 2003/11 [Refereed][Not invited]
     
    Seawater in a fishing port was electrolyzed to induce hypochlorite up to approximately 1 mg/L for the reduction of viable bacterial count because disinfection of seawater is important for the prevention and control of hazards in seafoods. The number of viable bacteria in a fish holding tank was lowered from 104-105 mg/L to 100-101 mg/L after electrolization of seawater and the low level of viable bacterial count was kept for at least 3 hours. The reduction rate of chlorine concentration of the electrolyzed seawater in the fish holding tank was reduced by the addition of ice and by covering with a thermal insulating sheet. However, the chlorine concentration decreased when fish were put into the fish holding tank. In a fisher-boat tank, viable bacterial count remained less than 100 CFU/mL for at least 60 minutes when ice was present. It was also shown that electrolyzed seawater was useful for disinfection of deck or fishing equipment.
  • 野村哲一, 笠井久会
    魚と卵 169 (169) 1 - 12 0288-8602 2003/03 [Not refereed][Not invited]
  • Hisae Kasai, Shuichi Osawa, Tadashi Kobayashi, Mamoru Yoshimizu
    Fish Pathology 日本魚病学会 37 (4) 199 - 200 0388-788X 2002/12 [Refereed][Not invited]
     
    Treatment of supplied water with a high quality ultraviolet (UV) lamp was examined for prevention of scuticociliatosis of farmed juvenile Japanese flounder (Paralichthys olivaceus). In an examination for the ciliate-cidal effect of UV irradiation, scuticociliates showed low susceptibility to UV compared with fish pathogenic viruses or bacteria, the minimal killing dosage being 2.0 × 105 μW · sec/cm2. UV treatment of supplied water to the tank was performed in a flounder farm in southern Hokkaido, where scuticociliatosis frequently occurred. It was revealed that the UV treatment at 3.0 × 105 μW · sec/cm2 was effective to prevent scuticociliatosis.
  • 笠井 久会, 中村 哲士, 吉水 守
    Bulletin of fisheries sciences, Hokkaido University 北海道大学大学院水産科学研究科 53 (2) 69 - 73 1346-1842 2002/08 [Not refereed][Not invited]
  • 笠井 久会, 中村 暢之, 吉水 守
    Bulletin of fisheries sciences, Hokkaido University 北海道大学大学院水産科学研究科 53 (2) 75 - 82 1346-1842 2002/08 [Not refereed][Not invited]
  • 吉水 守, 笠井 久会
    工業用水 日本工業用水協会 0 (523) 13 - 26 0454-1545 2002/04 [Not refereed][Not invited]
     
    総説
  • NOMURA Testsuici, HONMA Hiromi, KASAI Hisae, YOSHIMIZU Mamoru
    Bulletin of fisheries sciences, Hokkaido University 北海道大学大学院水産科学研究科 53 (1) 45 - 50 1346-1842 2002/03 [Not refereed][Not invited]
  • KASAI HISAE, YOSHIMIZU MAMORU, EZURA YOSHIO
    Fisheries science 公益社団法人 日本水産学会 68 (1) 821 - 824 0919-9268 2002 [Refereed][Not invited]
     
    Disinfection of water for aquaculture is critical for preventing the introduction and spread of infectious disease. A pathogen-free water source is essential for success in aquaculture. Typical treatment systems make use of high efficiency sand filters to clarify the water before treatment with ultraviolet (UV) light or ozonization. Fish pathogens are divided into two groups based on their sensitivity to UV and total residual oxidants (TROs) produced by ozonization of seawater. Hypochlorite produced by electrolysis of seawater (salt water) showed bactericidal and viricidal effects. This method can easily treat large volumes of water, and is suitable for disinfecting wastewater before discharging.
  • KASAI Hisae, YOSHIMIZU Mamoru
    Bulletin of fisheries sciences, Hokkaido University 北海道大学大学院水産科学研究科 52 (2) 67 - 70 1346-1842 2001/09 [Not refereed][Not invited]
  • KASAI Hisae, WATANABE Ken-ichi, YOSHIMIZU Mamoru
    Aquaculture Science 水産増殖談話会 49 (2) 237 - 241 0371-4217 2001/06/20 [Refereed][Not invited]
     
    The bactericidal and virucidal effects of hypochlorite produced by batch electrolytic system were examined for fish pathogens. Sodium chloride solutions, ranging from 0.5 to 3%, were electrolyzed and the concentration of chlorine produced was measured. Almost same concentration of chlorine was produced when 1.0% or more NaCI solution and seawater were electrolyzed. Fish pathogenic bacteria or virus was added to electrolyzed water and exposed to hypochlorite. More than 99% cells of Vibrio anguillarum, causative agent of fish vibriosis, were killed when the bacteria were exposed to 0.21mg/l hypochlorite for 1min. Yellowtail ascites virus (YAV) and hirame rhabdovirus (HIRRV), the causative agents of viral ascites disease and rhabdovirus disease of marine fish, were inactivated more than 99% after treatment with 0.42 mg/l hypochlorite for 1 min. The number of viable bacteria in the hatchery supply-seawater was reduced more than 99% when the water was treated with hypochlorite of 0.54 mg/l for 1 min. And more than 99% cells of viable bacteria in the waste-seawater were killed when the water was treated with hypochlorite of 0.64 mg/l for 5min. The batch system developed in this study revealed remarkable bactericidal and virucidal effects, which were very similar to those in continuous flow-water system.
  • Hisae Kasai, Ken Ichi Watanabe, Mamoru Yoshimizu
    Nippon Suisan Gakkaishi (Japanese Edition) 日本水産學會 67 (2) 222 - 225 0021-5392 2001/03 [Refereed][Not invited]
     
    The bactericidal effect of hypochlorite produced by a continuous flow electrolyzer on hatchery waste-seawater was investigated. The number of viable bacteria in the waste-seawater was reduced more than 99% when the water was treated with hypochlorite at 0.6 mg/L for 1 min, and over 99.9% of bacteria was reduced when treated with 1.0 mg/L for 1 min. In the next experiment, one part, 2.0 m3/h of hatchery waste-seawater was treated with electrolyzer and produced hypochlorite was mixed with the remaining, 16.5 m3/h waste-seawater. More than 99% of viable bacterial was reduced after treatment with 0.5 mg/L of total residual chlorine for 1 min. The bactericidal efficacy of electrolysis was almost the same as that of ultraviolet irradiation (1.0 × 105μW·sec/ cm2) or ozonization (TROs 0.5 mg/L, 1 min) of seawater. Electrolyzation is able to treat a large volume of waste seawater compared with the ultraviolet irradiation or ozonization.
  • Hisae Kasai, Asami Ishikawa, Yuhka Hori, Ken Ichi Watanabe, Mamoru Yoshimizu
    Nippon Suisan Gakkaishi (Japanese Edition) 日本水産學會 66 (6) 1020 - 1025 0021-5392 2000 [Refereed][Not invited]
     
    The bactericidal and virucidal effects of hypochlorite produced by electrolysis of salt water were examined for pathogenic bacteria and viruses of fish. A three percent solution of sodium chloride that contained pathogenic bacteria or virus was electrolyzed and the organisms were exposed to hypochlorite. More than 99.99% of the cells of Vibrio anguillarum and Aeromonas salmonicida, the causative agents of fish vibriosis and furunculosis respectively, were killed when the bacteria were exposed to 0.1 mg/l hypochlorite for one minute. Yellowtail ascites virus (YAV) and hirame rhabdovirus (HIRRV), the causative agents of viral ascites disease and rhabdovirus disease of marine fish, were inactivated >99.99% after treatment with 0.58 mg/l hypochorite for one minute. The bactericidal and virucidal effects of hypochlorite produced by electrolysis (3.5 m3/h, 0.1 A) are greater than those of the chemical reagent. The purity of the sodium chloride used influences the production of hypochlorite. Sodium chloride obtained as a super grade chemical reagent is more effective than sodium chloride that is used for food. However, a sufficient disinfectant effect was observed in electrolyzed seawater, which could be applied in aquaculture.

MISC

Books etc

  • 循環式陸上養殖Vol.2
    笠井久会, 永田, 淳 (Contributor62-68)
    緑書房 2024/06 (ISBN: 9784895319874)
  • Seafood safety and quality
    Kasai, H, S. Nishikawa (ContributorPrevention and treatment of diseases caused by fish pathogens)
    CRC press 2018/10
  • Seafood safety and quality
    Kasai, H, S. Nishikawa, K. Watanabe (ContributorViral diseases affecting aquaculture)
    CRC press 2018/10
  • Woo P. T. K, Cipriano Rocco C (ContributorOncogenic Viruses - Oncorhynchus masou Virus and Cyprinid Herpesvirus)
    CAB International 2017 (ISBN: 9781780647784)
  • 青木 宙, 飯田貴次, 中西照幸, 引間順一, 廣野育生, 舞田正志, 吉水 守, 伊丹利明, 上野隆二, 遠藤俊夫, 乙竹 充, 笠井久会, 近藤昌和, 酒井正博, 高橋幸則, 青木 宙 (Joint work)
    恒星社厚生閣 2013/08 (ISBN: 4769912811) 504
  • Woo P. T. K, Bruno David W (ContributorChapter 7; Oncogenic viruses and Oncorhyncus masou virus)
    CABI 2011 (ISBN: 9781845935542)
  • 阿部 周一, 天野哲也, 荒井克俊, 安東宏徳, 上田 宏, 浦野明宏, 帰山雅秀, 笠井久会, かじ さやか, 桜井泰憲, 佐藤俊平, 高橋是太郎, 永田光博, 伴 真俊, 矢部 衞, 山羽悦郎, 吉水 守, 阿部 周一編著 (Joint work)
    北海道大学出版会 2010/01 (ISBN: 4832981935) 270
  • 藤井 建夫, 杉田 治男, 左子 芳彦 (Contributor微生物による魚病原因ウイルスの制御)
    恒星社厚生閣 2007 (ISBN: 9784769910671)

Association Memberships

  • THE JAPANESE SOCIETY FOR MARINE BIOTECHNOLOGY   JAPAN AQUACULTURE SOCIETY   THE JAPANESE SOCIETY FOR VIROLOGY   THE JAPANESE SOCIETY OF FISHERIES SCIENCE   THE JAPANESE SOCIETY OF FISH PATHOLOGY   

Research Projects

  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research
    Date (from‐to) : 2023/04 -2026/03 
    Author : 笠井 久会, 工藤 秀明
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research
    Date (from‐to) : 2016/04 -2020/03 
    Author : Kasai Hisae
     
    Soft egg disease in salmonids causes loss of firmness of the egg membrane, increasing vulnerability of the embryo to external impact. In this study, we show that the disease is caused when bacteria from the environment gradually dissolve the surface of the egg membrane. We analyzed bacteria attached to egg membranes, and found candidate pathogenic bacteria to be short bacilli. Artificial culture of the pathogen was possible and a specific detection method was subsequently developed. Furthermore, we demonstrate how polyphenols can inhibit egg membrane softening.
  • ヒラメレオウイルス感染症の防除に関する研究
    公益財団法人北水協会：研究助成事業
    Date (from‐to) : 2018/04 -2019/03 
    Author : 笠井久会
  • サクラマスのヘルペスウイルス病および伝染性造血器壊死症防除 対策の強化に関する研究
    公益財団法人北水協会：試験研究費補助金
    Date (from‐to) : 2015/04 -2016/03 
    Author : 笠井久会
  • マツカワのウイルス性神経壊死症防除対策の強化に関する研究
    公益財団法人北水協会：試験研究費補助金
    Date (from‐to) : 2012/04 -2015/03 
    Author : 笠井久会
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research
    Date (from‐to) : 2013 -2015 
    Author : Kasai Hisae
     
    Oncorhynchus masou virus (OMV; Salmonid herpesvirus 2) is a member of Herpisviridae associated with oncogenic and hepatitic diseases of national and international socio-economic importance. The present study focused on oncogenesis and viral pathogenesis of OMV in salmonid fish. Viral genes were localized in the whole Tumor tissues of masu salmon Oncorhynchus masou that survived OMV infections. A strong ISH signal was detected in the tumor tissue indicating that OMV induces tumor development. Highly expressed viral genes in Tumor were found by transcriptome analysis using NGS-based RNA sequencing. Liver failure as well as renal dysfunction and failure of gill function were occurred in OMV-infected rainbow trout O. mykiss.
  • カキ腸内由来細菌の産生する抗ウイルス物質の構造と活用技術の開発
    公益財団法人ノーステック財団：研究開発助成事業（talent補助金）
    Date (from‐to) : 2012/08 -2013/02 
    Author : 笠井久会
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research
    Date (from‐to) : 2009 -2012 
    Author : YOSHIMIZU Mamoru, KASAI Hisae, NISHIZAWA Toyohiko, TAKAMI Ikuo, OSEKO Norihisa, OH Myung-Joo
     
    In this study, we developed a novel fish-immunization with a synthetic double-stranded RNA [Poly(I:C)] and live pathogenic viruses. The fishes immunized with live pathogenic virus, followed by administration of Poly(I:C), became a transient, non-specific antiviral state, and those fish survive the initial immunization with live virus, thereby mounting a specific protective immune response against the injected pathogenic virus. Strong protective immune response was observed in rainbow trout, Japanese flounder and sevenband grouper by Poly(I:C)-immunization with IHNV, VHSV and NNV, respectively. It is conceivable that Poly(I:C)-immunization will eventually be applicable to a wide range of fish species as well as other viruses.
  • 国立研究開発法人科学技術振興機構：産学が連携した研究開発成果の展開 研究成果展開事業 研究成果最適展開支援プログラム(A-STEP) 探索タイプ
    Date (from‐to) : 2011/08 -2011 
    Author : 笠井 久会
     
    海洋環境中からの抗ウイルス物質産生細菌の効率的なスクリーニング方法を確立し、カキ消化管より分離した細菌が高い抗カリシウイルス活性を有することを明らかにした。次いで、本菌が産生する抗カリシウイルス活性物質の精製法を確立し、物質の情報を明らかにした。水産分野における活用技術として、カキ体内に蓄積されるノロウイルス(カリシウイルスの一種)対策に用いるため、本菌のカキへの投与法を開発した。以上は培養可能なカリシウイルスを用いたモデル実験であり、実際のカキ体内での有効性、ノロウイルスに対する抗ウイルス活性を検討していく必要があり、企業と早い段階で連携し、実用化に向けた研究を進める必要がある。
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research
    Date (from‐to) : 2010 -2011 
    Author : KASAI Hisae
     
    Oncorhynchus masouvirus(OMV) disease is a hepatitic, oncogenic and skin ulcerative condition of national and international socio-economic importance. The OMV genome sequences of three strains including the high virulent strain against rainbow trout revealed about 160 kbp genome composed of a unique long sequence, and a unique short fragment flanked by inverted repeats. ORFs involved in pathogenicity or oncogenicity were found in OMV genome. Furthermore an effective vaccine was developed in which relative percent survival(RPS) reached 74%.
  • Ministry of Education, Culture, Sports, Science and Technology：Grants-in-Aid for Scientific Research(基盤研究(B))
    Date (from‐to) : 2005 -2008 
    Author : Mamoru YOSHIMIZU, 田島 研一, Toyohiko NISHIZAWA, Tomoo SAWABE, Hisae KASAI, Kenichi TAJIMA
     
    20℃以上に調温した0.3mg/Lの塩素を含む電解海水あるいは中圧紫外線処理海水を用い、V. alginolyticus優勢キートセロスを給餌しながら浄化すれば、カキが痩せることなく、大腸菌、ノロウイルスおよびV. parahaemolyticusを排除できると考えられる。さらに安全性を確保するために2,000気圧の高静水圧をかけて脱殻を行えば、安全性はより向上する。
  • 日本学術振興会：科学研究費助成事業
    Date (from‐to) : 2002 -2004 
    Author : 笠井 久会
     
    本年度,まず海水殺菌装置を使用する飼育施設ならびに対象とする病原体ごとのマニュアルを作成した。また,貝類の衛生管理に用いる殺菌装置の比較検討を行い,最適殺菌装置の選択を行い,さらに漁獲から加工場に至る間の水産物の衛生管理に向けた使用海水の最適殺菌条件を検討し,実用化に向けたマニュアルを作成した.その成果は以下の通りである。 1.昨年度の成果より,海産種苗生産現場に甚大な被害を及ぼすウイルス性神経壊死症の原因ウイルスNNVに対しては海水電解殺菌装置が適していた。同装置で処理した海水でヒラメを飼育しても問題がなく,飼育用水の殺菌にはNNVが不活化される有効塩素濃度2.4mg/L以上の濃度での運転を推奨した。飼育排水の殺菌には,流量の問題から紫外線やオゾンを用いた殺菌装置では対応できず,本装置のみが対応可能であった。 2.カキの浄化に紫外線殺菌海水や次亜塩素添加海水が用いられているが,低コストで大量の海水を処理することが出来る海水電解殺菌装置が最も適していた。北海道,宮城県および広島県で大腸菌の浄化試験を行い,紫外線と同等の除菌効果が得られた。また,培養不能なノロウイルスの代替ウイルスとしてFCVを供試し,電解処理したところ,有効塩素濃度0.43mg/Lで十分な不活化効果が得られた。同じ科に属すノロウイルスも同等の感受性を示すとすれば,感染性のノロウイルスを含まない浄化用水は,海水電解殺菌装置により十分得られることが明らかとなった。 3.港内海水中の大腸菌および大腸菌群による漁獲物の汚染を防ぐには,海水電解殺菌装置が有効であったため,漁船8隻の取水管に本装置を取り付けた。環境へ悪影響を与えないため,十分な殺菌効果が得られる最低濃度である0.3mg/Lでの運転を推奨した。本装置により得られる殺菌海水の利用と,温度管理や他の衛生管理対策との相乗効果で,漁獲物の衛生管理の向上につながると考える。

Social Contribution

  • 水産資源保護啓発研究活動推進委員
    Date (from-to) : 2007/02-2007/02
    Role : Advisor
    Sponser, Organizer, Publisher  : 社団法人日本水産資源保護協会

Academic Contribution

  • 科学技術専門調査員
    Date (from-to) :2012-2017
    Role: Academic research planning
    Type: Academic research
    Organizer, responsible person: 文部科学省科学技術・学術政策研究所 科学技術予測センター
  • アドバイザー
    Date (from-to) :2006/08-2009/03/31
    Type: Academic research
    Organizer, responsible person: 財団法人北海道科学技術総合振興センター

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