Advance

ISHIMARU Katsuya

    Aquaculture Research Institute, Kindai University　Lecturer
Last Updated :2024/04/23

Researcher Information

J-Global ID

Research Interests

  • fish pathogenic bacteria   

Research Areas

  • Life sciences / Aquaculture / fish pathology

Published Papers

  • Yasuhiko Kawato; Indah Istiqomah; Alkhateib Y. Gaafar; Makoto Hanaoka; Katsuya Ishimaru; Motoshige Yasuike; Issei Nishiki; Yoji Nakamura; Atushi Fujiwara; Toshihiro Nakai
    Archives of Virology Springer Science and Business Media LLC 165 (2) 303 - 311 0304-8608 2020/02 [Refereed]
     
    A novel jumbo bacteriophage (myovirus) is described. The lytic phage of Tenacibaculum maritimum, which is the etiological agent of tenacibaculosis in a variety of farmed marine fish worldwide, was plaque-isolated from seawater around a fish aquaculture field in Japan. The phage had an isometric head 110-120 nm in diameter, from which several 50- to 100-nm-long flexible fiber-like appendages emanate, and a 150-nm-long rigid contractile tail. The full genomes of the two representative phages (PTm1 and PTm5) were 224,680 and 226,876 bp long, respectively, both with 29.7% GC content, and the number of predicted open reading frames (ORFs) was 308 and 306, respectively. The average nucleotide sequence identity between PTm1 and PTm5 was 99.95%, indicating they are quite similar to each other. A genetic relationship was found in 15.0-16.6% of the predicted ORFs among the T. maritimum phages PTm1 and PTm5, the Tenacibaculum spp. phage pT24, and the Sphingomonas paucimobilis phage PAU. Phylogenetic analysis based on the terminase large subunit genes revealed that these four phages (PTm1, PTm5, pT24 and PAU) are more closely related than the other 10 jumbo myoviruses that have similar genome sizes. Transmission electron microscopy observations suggest that the head fibers of the T. maritimum phage function as tentacles to search and recognize the host cell surface to facilitate infection.
  • Improvement of bacterial disease resistance of red seabream Pagrus major by oral administration of Kumazasa Sasa veitchii extract
    Katsuya Ishimaru; Soichi Makino; Yuuzou Tsuchida
    Bulletin of the Aquaculture Research Institute, Kindai University (19) 25 - 34 2019/03
  • Sho Shirakashi; Kazuki Tani; Katsuya Ishimaru; Tomoki Honryo; Sang Phil Shin; Hiro'omi Uchida; Kazuo Ogawa
    JOURNAL OF PARASITOLOGY AMER SOC PARASITOLOGISTS 103 (5) 541 - 546 0022-3395 2017/10 [Refereed]
     
    Fish blood flukes of the genus Cardicola (Digenea: Aporocotylidae) are important pathogens in tuna aquaculture. Recent advances in marine blood fluke research have led to the elucidation of the lifecycles of 3 Cardicola spp. infecting tuna; all 3 flukes utilize terebellid polychaetes as the intermediate host. In our survey, we obtained large numbers of Nicolea gracilibranchis infected by larval Cardicola orientalis at our tuna farming site. To determine the spatial and temporal changes in the distribution of N. gracilibranchis surrounding tuna culture cages and their infection by C. orientalis, we conducted monthly sampling for a period of 1 yr. Terebellids were most abundant on the floats and ropes of culture cages, but a significantly higher proportion of infected N. gracilibranchis was detected on ropes, particularly up to 4 m in depth. Cardicola orientalis infection in N. gracilibranchis was clearly seasonal, with a higher infection rate between April and July. Our findings indicate that the infected terebellids inhabit specific microhabitats, and both abiotic and biotic factors likely influence blood fluke infection in the intermediate terebellid host. This information is important to better understand the general biology of marine aporocotylids and may be useful to develop a control strategy for blood fluke infection in tuna aquaculture.
  • Kazuo Ogawa; Sho Shirakashi; Kazuki Tani; Sang Phil Shin; Katsuya Ishimaru; Tomoki Honryo; Yukitaka Sugihara; Hiro'omi Uchida
    PARASITOLOGY INTERNATIONAL ELSEVIER IRELAND LTD 66 (1) 972 - 977 1383-5769 2017/02 [Refereed]
     
    Farming of Pacific bluefin tuna (PBT), Thunnus orientalis, is a rapidly growing industry in Japan. Aporocotylid blood flukes of the genus Cardicola comprising C orientalis, C. opisthorchis and C. forsteri are parasites of economic importance for PBT farming. Recently, terebellid polychaetes have been identified as the intermediate hosts for all these parasites. We collected infected polychaetes, Terebella sp., the intermediate host of C. opisthorchis, from ropes and floats attached to tuna cages in Tsushima, Nagasaki Prefecture, Japan. Also, Neoamphitrite vigintipes (formerly as Amphitrite sp. sensu Shirakashi et al., 2016), the intermediate host of C. forsteri, were collected from culture cages in Kushimoto, Wakayama Prefecture, Japan. The terebellid intermediate hosts harbored the sporocysts and cercariae in their body cavity. Developmental stages of these blood flukes were molecularly identified using species specific PCR primers. In this paper, we describe the cercaria and sporocyst stages of C. opisthorchis and C. forsteri and compare their morphological characteristics among three Cardicola blood flukes infecting PBT. We also discuss phylogenetic relations of the six genera of the terebellid intermediate hosts (Artacama, Lanassa, Longicarpus, Terebella, Nicolea and Neoamphitrite) of blood flukes infecting marine fishes, based on their morphological characters. (C) 2016 Elsevier Ireland Ltd. All rights reserved.
  • Sho Shirakashi; Kazuki Tani; Katsuya Ishimaru; Sang Phil Shin; Tomoki Honryo; Hiro'omi Uchida; Kazuo Ogawa
    PARASITOLOGY INTERNATIONAL ELSEVIER IRELAND LTD 65 (2) 128 - 136 1383-5769 2016/04 [Refereed]
     
    Fish blood flukes (Aporocotylidae) are important pathogens of farmed finfish around the world. Among them, Cardicola spp. infecting farmed tuna are considered to be serious threats to tuna farming and have received tremendous attention. We conducted periodical samplings at a tuna farming site in Japan between January and May, 2015 to determine the life cycle of Cardicola spp. We collected over 4700 terebellid polychaetes from ropes, floats and frames of tuna culture cages and found nearly 400 infected worms. Sporocysts and cercariae found in Nicolea gracilibranchis were genetically identified as Cardicola orientalis by 28S and ITS2 ribosomal DNA sequences. This was the first discovery of the intermediate host for this parasite species. Infection prevalence and the abundance of N. gracilibranchis significantly varied between sampling points and the highest number of infected terebellids were collected from ropes. We also demonstrated morphologically and molecularly that asexual stages found in a single Amphitrite sp. (Terebellidae) and adult worms isolated from farmed juvenile tuna were Cardicola forsteri. This is the first report of C forsteri in Pacific bluefin tuna (PBT) Thunnus orientalis in Japan. Our results demonstrated that all three species of Cardicola orientalis, C. forsteri and Cardicola opisthorchis exist in Japanese farmed PBTs and that they all use terebellid polychaetes as the intermediate hosts. (C) 2015 Elsevier Ireland Ltd. All rights reserved.
  • Osamu Takaoka; Seung-Cheol Ji; Katsuya Ishimaru; Si-Woo Lee; Gwan-Sik Jeong; Amal Biswas; Kenji Takii
    AQUACULTURE RESEARCH WILEY-BLACKWELL 47 (2) 390 - 397 1355-557X 2016/02 [Refereed]
     
    Red sea bream Pagrus major (RSB) weighing 0.09g were fed on test diets, composed of 65% fish meal supplemented with 0.49% Crataegi fructus (Cf) and a mixture of Massa medicata, Cf, Artemisia capillaries and Cnidium officinale (HM) or a control diet without herbs, in trial 1. After air exposure and anaesthesia treatment, higher stress tolerances were obtained in herbal groups than control group. Moreover, after challenge test with Vibrio anguillarum, mortalities of the herbal groups were lower than the control group. There was no significant difference in growth performance among the treatments. Feed efficiency (FE) of the test groups was 124-141%. In trial 2, RSB weighing 0.11g were fed on diets composed of 35% fish meal and 30% enzyme treated fish meal (EFM) with the same herbal treatments as trial 1. The herbal groups revealed higher final body weight and specific growth rate (SGR) and lower daily feed intake than those of the control group. The FE of test groups was 172-203%. These results indicate that the dietary herbs supplementation acts not only as recovery enhancer for some rearing stresses but also as growth enhancer, which is accelerated with dietary EFM in the early juvenile stage of red sea bream.
  • Michitaka Yamamoto; Kazuhiro Sugahara; Makoto Endo; Katsuya Ishimaru; Keitaro Kato
    FISH PATHOLOGY JAPAN SOC FISH PATHOL DEPT FISHERIES-FAC AGR 50 (3) 97 - 104 0388-788X 2015/09 [Refereed]
     
    We studied the epidemiology of Flavobacterium psychrophilum in ayu from Lake Biwa for establishing control measures to bacterial cold water disease (BCWD). During 1998-2011, 12,743 wild ayu were collected from coastal (set net and gill net), offshore (offshore scoop net) and inflow river (fishing weir) areas of Lake Biwa. We employed a nested-FOR technique targeting 16S rRNA gene for the detection of F. psychrophilum in the gills and kidney of ayu. Prevalence of the bacterium was greatest when the water temperature of Lake Biwa was 18-21 degrees C, which coincides with the optimum temperature for multiplication of F. psychrophilum. The prevalence of F. psychrophilum in the gills was higher in fish from fishing weirs and set nets maintained in net cages than in fish just after catch with the other fishing techniques. This suggests that rearing ayu in net cages at high densities following catch by fishing weirs and set nets can advance infection with the bacterium among the captured fish which will be used for seedlings in aquaculture or releasing in rivers. Control measures for the captured ayu must be conducted in reliable ways to prevent spread of the disease after release and in aquaculture.
  • Chihaya Hirano; Katsuya Ishimaru; Sho Shirakashi
    FISH PATHOLOGY JAPAN SOC FISH PATHOL DEPT FISHERIES-FAC AGR 50 (1) 23 - 28 0388-788X 2015/03 [Refereed]
     
    Diurnal rhythms in egg laying and hatching of the skin fluke Neobenedenia girellae were investigated under different light conditions. Egg production was monitored every 2 h for 3 days under two light conditions (darkness and natural light) using Seriola dumerili infected with multiple Neobenedenia girellae as well as black molly Poecilia sphenops that had been transplanted by a single mature fluke. In any cases, oviposition was continuously observed with no obvious diurnal rhythm. The maximum egg production was approximately 60 eggs/h/worm for both multiple- and single-infection. Such high fecundity emphasizes the importance of the prompt eradication of mature flukes from culture sites to prevent parasite multiplication. The hatching rhythm was monitored under natural light condition and controlled light condition with LED lamp (24L, 12L:12D, 24D). An obvious hatching rhythm with a monomodal peak in the morning was detected under natural light condition. This rhythm was different from that previously reported for Benedenia seriolae whose hatching has bimodal peaks in the early morning and evening. Under controlled light conditions, no such pattern was observed and the overall hatching was considerably less than that under natural light condition.
  • 平野千早; 石丸克也; 白樫 正
    魚病研究 50 (1) 23  2015/03 [Refereed]
  • Shinji Yamamoto; Atsuhiko Fukushima; Katsuya Ishimaru; Sho Shirakashi
    FISHERIES SCIENCE SPRINGER JAPAN KK 80 (5) 1021 - 1026 0919-9268 2014/09 [Refereed]
     
    The skin fluke Neobenedenia girellae has become a serious problem in Japan since the 1990s. Present control methods focus on the removal of the attached parasite and these post-infection treatments are often labor intensive, time consuming, and/or stressful to fish. Chub mackerel Scomber japonicus are highly susceptible to N. girellae. However, because of their sensitive nature, bath treatments may cause mortality. In this study, we investigated the efficacy of cage shading to reduce skin fluke infection and the frequency of conventional post-infection treatments. Juvenile mackerel were reared in cages with or without shade for 3 months and their skin fluke infections were monitored. We performed either freshwater baths or oral administration of praziquantel if fluke intensity exceeded the given criteria. In unshaded cages, 3 total bath treatments or 6 total drug treatments were conducted. In contrast, no treatment was required for the shaded cage. The overall fluke intensity in the shaded cage was less than half that of the unshaded cages, despite the lack of treatments. This study demonstrated for the first time the practical use of shading in fish farms to reduce skin fluke infection.
  • Sho Shirakashi; Tomoyo Nishimura; Nagaharu Kameshima; Hiroshi Yamashita; Hiroe Ishitani; Katsuya Ishimaru; Hiroshi Yokoyama
    FISH PATHOLOGY JAPAN SOC FISH PATHOL DEPT FISHERIES-FAC AGR 49 (3) 141 - 144 0388-788X 2014/09 [Refereed]
     
    Kudoa infections have recently become a serious concern in Japanese fisheries. Some species not only cause fish diseases and reduce the commodity value of fish, but also affect human health. We investigated whether the ultraviolet (UV) treatment of culture water prevented infections with two species of Kudoa, K. yasunagai and K. amamiensis, in Seriola lalandi and S. quinqueradiata, respectively. Rearing in untreated filtered seawater resulted in high infection rates, suggesting that the physical filtration systems used in this study did not sufficiently remove the infective stages of these Kudoa species. In contrast, commercially available UV irradiation system effectively prevented the infections with K. yasunagai and K. amamiensis.
  • Katsuya Ishimaru; Takumi Matsuura; Kazunobu Tsunemoto; Sho Shirakashi
    DISEASES OF AQUATIC ORGANISMS INTER-RESEARCH 108 (1) 45 - 52 0177-5103 2014/02 [Refereed]
     
    Kudoid myxozoans pose serious chronic problems in marine fisheries by causing pathological damage to host fish, reducing the market value of infected fish and potentially threatening public health. Kudoa yasunagai is a cosmopolitan parasite that infects the brains of various marine fishes, including important aquaculture species. We developed a quantitative PCR assay to detect K. yasunagai in sea water, and we used it to monitor abundance of the parasite in the environment and in culture through spring and winter. Quantitative PCR detected K. yasunagai DNA from sea water, with the lowest reliable threshold of 162 copies 28S rDNA l(-1). Parasite DNA was detected sporadically in sea water throughout the study period of May through December 2012. The highest level of detected DNA occurred in mid-December (winter), at 117 180 copies-equivalent to an estimate of over 200 myxospores l(-1). Parasite DNA was generally not detected in August or September, the period with the highest water temperature. The reason for this observation is unknown, but the timing of parasite development may play a role. The amount of detected DNA was not different between unfiltered culture water and water filtered through a high-speed fiber filtration system. This result and the past incidence of high infection rate of fish reared in filtered water indicate that the mechanical removal of K. yasunagai from culture water is difficult. Detecting the precise onset and time window of infection in host fish will be an important step in the development of measures to control this economically important parasite.
  • Sho Shirakashi; Chihaya Hirano; Hiroe Ishitani; Katsuya Ishimaru
    AQUACULTURE ELSEVIER SCIENCE BV 402 19 - 23 0044-8486 2013/07 [Refereed]
     
    Skin fluke infection is a major parasitic problem in the aquaculture industry. Present control measures such as bath treatments are effective for removing flukes from fish but require extensive labour and time. Moreover, bath treatments cause great stress to the fish, and occasionally lead to post-treatment mortality. Our ultimate goal is to develop a culture technique that prevents or lowers the chance of fish encountering larval skin flukes, thus reducing infection. However, little is known about when and where these infections occur on fish farms. We conducted a field experiment at a culture site to determine the diurnal pattern of skin fluke infection at different water depths. Juvenile amberjack, Seriola dumerili, were placed in enclosed mesh cages and exposed to skin flukes at depths of 0, 2 or 4 m for 4 h during different times of the day. A Neobenedenia girellae infection occurred predominantly at the surface during the mid-day. The infection rate declined considerably during the night. The parasite burden was significantly decreased with water depth, and up to an 80% and 95% reduction in intensities was observed when fish were exposed at a depth of 2 and 4 m, respectively. These results suggest that skin fluke infection can be significantly reduced by systematic management strategy and modification of culture techniques. (c) 2013 Elsevier B.V. All rights reserved.
  • Katsuya Ishimaru; Ryoma Mine; Sho Shirakashi; Eri Kaneko; Kazushige Kubono; Tokihiko Okada; Yoshifumi Sawada; Kazuo Ogawa
    AQUACULTURE ELSEVIER SCIENCE BV 402 24 - 27 0044-8486 2013/07 [Refereed]
     
    Blood flukes of the genus Cardicola cause significant problems in the bluefin tuna farming around the world. In Japan, the mortality of the juvenile Pacific bluefin tuna Thunnus orientalis (PBT) caused by C. orientalis and C. opisthorchis has become a serious issue in the tuna farming industry in recent years. Oral treatment with praziquantel (PZQ) is highly effective against blood flukes and is indispensable for sustainable tuna farming. To develop a proper and safe drug treatment procedure, we investigated the minimum effective dose and pharmacokinetics of PZQ in juvenile PBT. Juvenile tuna were orally administered various doses of PZQ (0, 3.75, 7.5, 15 and 30 mg/kg body weight (BW)) once a day for 3 consecutive days, and the occurrence of C. opisthorchis before and after the treatment was compared. A significant decrease in the number of flukes was observed in the 3.75 mg/kg group, and complete eradication of flukes was achieved at dosages of 7.5 mg/kg and greater. This result indicates that the minimal effective dose of PZQ for treating C. opisthorchis is between 3.75 and 7.5 mg/kg, which is less than 1/20 of the treatment dose used for treating the skin fluke Benedenia seriolae in yellowtail culture. We used high-performance liquid chromatography analysis to assess the temporal changes in the concentrations of PZQ in serum, muscle, the liver and the kidney after a single administration of PZQ at 15 mg/kg BW. The PZQ concentration in the tissues peaked between 0.5 and 1.5 h following administration, and PZQ was undetectable after 24 h. The highest serum concentration was 2.0 mu g/mL, which is likely to be the lethal dose for C. opisthorchis. These results suggest that PZQ treatment is a highly effective and relatively safe method to control blood flukes in the tuna farming industry. (c) 2013 Elsevier B.V. All rights reserved.
  • Sho Shirakashi; Chihaya Hirano; Asmahani Binti Asmara; Noorashikin Binti Md Noor; Katsuya Ishimaru; Shigeru Miyashita
    Fish Pathology 48 (1) 25 - 28 0388-788X 2013 [Refereed]
     
    Juvenile greater amberjack were placed in asmall cage and exposed to Neobenedenia girellae oncomiracidiaofr 84 hta na maberjack culture site under naturallight or with a shade.The shading reduced worm intensityon hte ksin fo isfh yb baout 07%.Additional laboratoryexperimental infection comparing the larval infectivity underdark and light conditions revealed that the oncomiracidiawere capable of infecting fish in complete darkness.These results suggest that the low infection rate in theshaded water is probably due to accumulation of theoncomiracidia into the bright area, resulting in the lowereddensity under the shade © 2013 The Japanese Society of Fish Pathology.
  • Katsuya Ishimaru; Naoki Iida; Takahiko Okada; Shigeru Miyashita
    FISH PATHOLOGY JAPAN SOC FISH PATHOL DEPT FISHERIES-FAC AGR 47 (4) 143 - 146 0388-788X 2012/12 [Refereed]
     
    In July 2003, we observed abnormal opaqueness of both the yolk in the embryos and recently hatched larvae of Pacific bluefin tuna Thunnus orientalis spawned at the Ohshima Experimental Station in Wakayama, Japan. The yolks were infected with a number of a unicellular parasite. All the infected yolk sacs burst one day post-hatch. Consequently, all the host larvae died and the parasites were released into seawater. The infection rate of this disease was less than 16% in 2003 but spiked up to 98% in 2004. However, the disease has not been observed since 2006. The pathogen has been identified as Ichthyodinium sp. belonging to Alveolata.
  • Sho Shirakashi; Akinobu Morita; Katsuya Ishimaru; Shigeru Miyashita
    DISEASES OF AQUATIC ORGANISMS INTER-RESEARCH 101 (2) 123 - 130 0177-5103 2012/11 [Refereed]
     
    We monitored infection by a brain-infecting myxozoan Kudoa yasunagai in hatchery-reared juvenile yellowtail Seriola quinqueradiata at a culturing site in Japan. Infection was detected by PCR and microscopic observation once every 1 to 4 wk during 2010 and 2011. In both years, we detected first infection in mid-July by PCR. Prevalence increased rapidly after the onset of infection, peaking at 100% within 4 wk. Parasites required less than 10 d to reach the brain after invasion. Development of plasmodia and formation of cysts took 4 to 8 wk. Infection did not reach a plateau and number of cysts tended to decline over time, suggesting possible recovery from the infection. A drastic decline in infection prevalence was observed during the season of highest water temperature (>30 degrees C) in 2010. To understand this phenomenon, we conducted a laboratory experiment to compare infection prevalence and cyst formation in fish kept at 25 degrees C and 30 degrees C. However, we could not detect obvious differences between the treatment groups during the 4 wk of the experiment. There was no apparent pathology associated with the infection. These results suggest that pathological effects of K. yasunagai may differ between fish species or that other factors are important in the development of infectious signs.
  • TAKAOKA Osamu; JI Seung-Cheol; ISHIMARU Katsuya; LEE Si-Woo; JEONG Gwan-Sik; BISWAS Amal; TAKII Kenji
    Aquaculture Science Japanese Society for Aquaculture Science 60 (2) 199 - 205 0371-4217 2012/06 [Refereed]
     
    The effect of dietary medicinal herbs, the herb mixture (HM) of Massa medicata, Crataegi fructus (Cf), Artemisia capillaries and Cnidium officinale, and single Cf, on various challenge and physical stress tests were examined for early three stages of striped jack. The larvae at 3 days after hatching, juveniles at the transportation from a land tank to a net cage and fingerlings at the body size before a shipment were given rotifer Brachionus plicatilis sp. complex and test diets, with or without the extract and fine powder of medicinal herbs, respectively. Final body weight of juveniles fed diets with the extracts was heavier than those fed diet without the extract. However, larvae fed rotifer with herb extract induced higher survival than those fed control rotifer without herbs against the challenge test with Vibrio anguillarum. The herbal groups of larvae, juvenile and fingerling showed slightly higher and shorter tendency in the survival and recovery time after air exposure than the control group. The herbal groups of juvenile showed shorter recovery time after the anesthesia than control group. Furthermore, the herbal groups of fingerling appeared longer LD50 time than control group against the low specific gravity stress. These results indicate the possibility that Cf and HM in rotifer and diets are useful to improve various stress resistance, connecting to the mass fingerling production of striped jack.
  • Sho Shirakashi; Yoshiki Kishimoto; Ryuhei Kinami; Hiromitsu Katano; Katsuya Ishimaru; Osamu Murata; Naoki Itoh; Kazuo Ogawa
    PARASITOLOGY INTERNATIONAL ELSEVIER IRELAND LTD 61 (2) 242 - 249 1383-5769 2012/06 [Refereed]
     
    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 on entails and C. opisthorchis, respectively. Eggs of the former species were more abundant (maximum: 6900 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. (C) 2011 Elsevier Ireland Ltd. All rights reserved.
  • Development of feeding technology, formula diet, and parasite countermeasures for Pacific bluefin tuna, Thunnus orientalis.
    Y. Ishibashi; K. Takii; O. Murata; K. Ishimaru; A. Biswas; G. Nakase; S. Shirakashi
    Proceedings of the Final Global COE International Symposium of Kinki University, Kushimoto, November 23-24, 2012, Kinki Univ. Press 14 - 25 2012
  • Sho Shirakashi; Melanie Andrews; Yoshiki Kishimoto; Katsuya Ishimaru; Takahiko Okada; Yoshifumi Sawada; Kazuo Ogawa
    AQUACULTURE ELSEVIER SCIENCE BV 326 15 - 19 0044-8486 2012/01 [Refereed]
     
    Aquaculture of tuna has shown exponential growth in the recent years. In association with the global development of tuna aquaculture, problems with parasitic infections have arisen. Among the parasites found in cultured tuna, blood flukes are considered to be a significant threat as their eggs accumulate in the gills and interfere with the gas exchange process. To date, two species of blood fluke from the genus Cardicola have been found in Pacific bluefin tuna (Thunnus orientalis, PBT) cultured in Japan. We conducted an experiment to develop a drug treatment against the blood flukes of cultured tuna. Artificially produced juvenile tuna that were naturally infected with blood flukes were orally administered with anthelmintic praziquantel (PZQ) of 150, 15, 1.5 and 0 mg kg(-1) BW for three consecutive days, and differences in the abundance of adults and eggs in the gills were assessed. In the fish given 150 and 15 mg kg(-1) BW PZQ, adult worms in the heart ventricle were eradicated by day 8 post treatment with the number of eggs in the gills gradually declining over time. However, small numbers of adults re-appeared by week 3 or 5 post treatment. The drug does not seem to affect eggs as viable miracidia were observed throughout the experiment. Mortalities in the two lower dose groups were significantly higher than the groups in which PZQ doses were shown to be effective. The study empirically demonstrated the efficacy of PZQ on Cardicola blood flukes and that the parasite significantly affects the survival of juvenile PBT. The oral PZQ treatment may be an essential practice for sustainable aquaculture of PBT. (C) 2011 Elsevier B.V. All rights reserved.
  • Osamu Takaoka; Seung-Cheol Ji; Katsuya Ishimaru; Si-Woo Lee; Gwan-Sik Jeong; Junichi Ito; Amal Biswas; Kenji Takii
    AQUACULTURE RESEARCH WILEY-BLACKWELL 42 (12) 1824 - 1829 1355-557X 2011/11 [Refereed]
     
    The effects of the dietary medicinal herbs Massa medicata, Crataegi fructus (Cf), Artemisia capillaries, Cnidium officinale and their mixture (HM), on growth and resistance against Vibrio anguillarum were examined using larval red sea bream, Pagrus major. The methanol extracts of Cf and HM inhibited the proliferation of seven infectious bacterial strains including the genera Aeromonas, Edwasiella, Photobavterium, Pseudomonas and Vibrio. Rotifers enriched with emulsified bonito oil containing extracts of Cf and HM lowered the bacterial counts in their body on TCBS medium for the genus Vibrio in comparison with rotifers enriched by emulsified bonito oil alone. Although statistically not significant, larvae fed rotifer fortified with Cf from 3 to 20 days after hatching showed the best growth and final body weight followed by those given rotifer with HM and control enrichment. However, final body length of larvae fed rotifer with Cf was significantly larger than larvae fed on rotifers enriched with other herb extracts. After a challenge test with V. anguillarum, survival of larvae fed rotifer with Cf and HM was significantly higher than for the control treatment. These results revealed that Cf and HM in rotifer is useful to promote growth and resistance against V. anguillarum in red sea bream larvae, providing a new technology for mass production of disease-resistant fry and fingerlings.
  • K. Ogawa; K. Ishimaru; S. Shirakashi; I. Takami; D. Grabner
    PARASITOLOGY INTERNATIONAL ELSEVIER IRELAND LTD 60 (3) 307 - 312 1383-5769 2011/09 [Refereed]
     
    A new aporocotylid blood fluke is described, based on specimens from the ventricle of the Pacific bluefin tuna, Thunnus orientalis (Temminck et Schlegel), cultured in Wakayama and Nagasaki Prefectures, Japan. The new species is morphologically similar to the members of the genus Cardicola Short, 1953, but shows distinct differences in the body form, location of the testis and the orientation of the ootype. The body of the new species is long and slender, whereas other Cardicola species are small and generally lanceolate. The testis is mostly located posterior to the caeca and anterior to the ovary, occupying 31-45% of body length, in contrast to the known Cardicola species, whose testis is typically intercaecal. The ootype is oriented anteriorly, while in most congeners, it is directed posteriorly or horizontally. Phylogenetic analyses of this aporocotylid, together with Cardicola orientalis Ogawa, Tanaka, Sugihara et Takami, 2010 from the same host, were conducted based on DNA sequences of the ITS2 rDNA and the 28S region of ribosomal RNA. The analyses revealed that the new blood fluke belongs to the genus Cardicola despite the marked morphological differences. Thus, this aporocotylid is named Cardicola opisthorchis n. sp. and the generic diagnosis is emended in this paper. In addition, 100% identity among the ITS2 sequences from the present species, Cardicola sp. from T. orientalis in Mexico and Cardicola sp. from the northern bluefin tuna, Thunnus thynnus (Linnaeus) in Spain suggests that C. opisthorchis n. sp. has a broad geographical distribution and that it infects both the Pacific and northern bluefin tuna. (C) 2011 Elsevier Ireland Ltd. All rights reserved.
  • Shinji Yamamoto; Sho Shirakashi; Satoshi Morimoto; Katsuya Ishimaru; Osamu Murata
    AQUACULTURE ELSEVIER SCIENCE BV 319 (1-2) 53 - 57 0044-8486 2011/09 [Refereed]
     
    Outbreaks of skin flukes and associated mortalities have been observed in cultured chub mackerel, Scomber japonicus. Although freshwater bathing effectively removes the parasites, large post-treatment mortalities are occasionally observed especially under high water temperature conditions due to the stress from handling and confinement. Since outbreaks of the skin fluke infections often occur in high temperature seasons, development of an effective and safe control method is essential for the advancement of mackerel aquaculture. The present study aims to: 1) identify the skin fluke of cultured chub mackerel and 2) develop an alternative control measure using oral drug administration. The skin fluke was identified as Neobenedenia girellae by morphology and molecular data targeting ITS region of rDNA. Two trials of oral administration of praziquantel (PZQ), a common anthelmintic, were conducted and parasite intensity was compared before and after the treatment and between treated and untreated control fish. Fish rejected PZQ-coated commercial pellets, but oral administration was successfully achieved using frozen krill as a basal diet The three-day administration with a dose of 150 mg.kg(-1) BW.day(-1) resulted in over 80% reduction in worm intensity. However, some proportion of the skin flukes survived the drug treatment The resistance to PZQ does not relate to worm's developmental stage. Freshwater bathing was more effective and eradicated the parasite, but some post-treatment mortality of host fish was observed. Moreover, the parasite intensity drastically increased after the freshwater bathing, possibly due to stress and loss of mucus during the bathing. The study indicates the PZQ oral treatment is effective to control N. girellae in chub mackerel aquaculture when the drug is properly administrated with an appropriate feeding technique. (C) 2011 Elsevier B.V. All rights reserved.
  • F. Meng; H. Yokoyama; S. Shirakashi; D. Grabner; K. Ogawa; K. Ishimaru; Y. Sawada; O. Murata
    PARASITOLOGY INTERNATIONAL ELSEVIER IRELAND LTD 60 (1) 90 - 96 1383-5769 2011/01 [Refereed]
     
    Kudoa prunusi n. sp. (Myxozoa; Multivalvulida) is described from the brain of Pacific bluefin tuna Thunnus orientalis cultured in Japan. Numerous white cysts, up to 0.5 mm in size, were found on and in the brain. Spores having typically five spore valves and five polar capsules resembled a five-petal cherry blossom in apical view and were conical shape with a round bottom in side view. Average spore size was 9.63 (8.5-10.3)mu m in width and 7.50 (6.7-8.6)mu m in length. The spore dimensions of K. prunusi overlapped with those of Kudoa yasunagai ex Sillago ciliata having five to six spore valves, but they were clearly distinct in spore shape, 18S rDNA and 28S rDNA sequences (0.3% and 1.7% differences, respectively). Phylogenetic analysis of 18S rDNA revealed that K. prunusi grouped with the brain-infecting multivalvulid species, K. yasunagai, K. chaetodoni, K. lethrini and K. neurophila, rather than five-valved Kudoa spp. Combined with morphological, molecular and biological differences, K. prunusi was proven to be a new species. (C) 2010 Elsevier Ireland Ltd. All rights reserved.
  • Effect of rotifer enrichment with herval extracts on growth and resistance of red sea bream, Pagrus major.
    滝井 健二; 高岡 治; 石丸 克也; ビッシャシュ アマル
    Aquacult. Res., in press 2010
  • Kohsuke Adachi; Keitaro Kato; Masayoshi Yamamoto; Katsuya Ishimaru; Toru Kobayashi; Osamu Murata; Hidemi Kumai
    AQUACULTURE ELSEVIER SCIENCE BV 296 (1-2) 110 - 116 0044-8486 2009/11 [Refereed]
     
    We cloned the prolactin (PRL) and somatolactin (SL) genes of Pacific bluefin tuna (PBT: Thunnus orientalis) and investigated their daily mRNA expression patterns under aquacultured conditions. The PRL and SL cDNAs of PBT encode 211 and 231 aa prehormones which give rise to 187 and 207 aa mature peptides, respectively, and which belong to the same clades as those of other Perciformes. The highest gene expression levels of PRL and SL in PBT were found at 6 am under natural light conditions, which is about 3 times higher than the constitutive levels in both cases. Interestingly, scatter diagrams show a strictly correlated expression between PRL and SL (r=0.82: p<0.01) while no correlation was found between PRL or SL and the growth hormone (GH). These results suggest that PRL and SL play synchronized role(s) in daily physiological phases of PBT under aquacultured conditions. (C) 2009 Elsevier B.V. All rights reserved.
  • Seung-Cheol Ji; Osamu Takaoka; Si-Woo Lee; Jae-Ho Hwang; Yang-Su Kim; Katsuya Ishimaru; Manabu Seoka; Gwan-Sik Jeong; Kenji Takii
    FISHERIES SCIENCE SPRINGER TOKYO 75 (3) 665 - 672 0919-9268 2009/05 [Refereed]
     
    The effect of dietary medicinal herbs on lipid metabolism and stress recovery was investigated in red sea bream Pagrus major. Fish (mean body weight 24.0 +/- A 0.2 g) were fed on test fish meal diets supplemented with either Massa Medicata (Mm), Crataegi Fructus (Cf), Artemisia capillaries (Ac), or Cnidium officinale (Co), or with a mixture of the four herbs (HM) for 12 weeks. A control group was fed a diet without herbs in the same manner. A high survival rate was observed in the herbal diet groups. The final mean body weight, feed efficiency, protein efficiency ratio, and apparent protein and lipid retention in the Ac, Co, and HM groups were higher than those in the control and Mm groups. Final carcass, hepatic lipid and triglyceride contents, and plasma triglyceride and nonesterified fatty acid levels were lower in the Ac, Co, and HM groups compared to those of control and Mm groups. However, final hepatic phospholipid, plasma phospholipid, and high density lipoprotein cholesterol levels were higher in the Ac, Co, and HM diets groups than in the control and Mm groups. The Cf, Co, Ac, and HM groups showed faster recovery time in the 2-phenoxyethanol anesthesia test and a higher recovery rate in the 10-min air exposure test than those of the control and Mm groups. Moreover, the Cf, Ac, Co, and HM diet groups had a significantly lower plasma cortisol level than the control and Mm diet group, but the glucose level in the herbal diet groups was higher than that in the control group after a 1-h air exposure. These results indicate that the addition of medicinal herbs to the fish diet improved lipid utilization and stress recovery in red sea bream.
  • Kohsuke Adachi; Keitaro Kato; Masayoshi Yamamoto; Katsuya Ishimaru; Toru Kobayashi; Osamu Murata; Hidemi Kumai
    AQUACULTURE ELSEVIER SCIENCE BV 281 (1-4) 158 - 161 0044-8486 2008/09 [Refereed]
     
    The daily expression profile of growth hormone (GH) mRNA in juvenile Pacific bluefin tuna (Thunnus orientalis) was investigated under aquacultured conditions. Total RNA from pituitaries (n=5) was sampled from 10 am to 12 pm the next day at 1 h intervals. The expression levels of GH mRNA were evaluated using real-time PCR normalized against the beta-actin gene. The expression level of GH transcripts reached a peak at 3-4 am at which time it was about 10 times higher than at any other time period. Considering their high growth rate compared to red seabream (Pagrus major) and other aquacultured species which shows continuous CH mRNA expression patterns, it can be concluded that the pulsed expression of GH mRNA just before daybreak is a key for the extremely high somatic growth rate of Pacific bluefin tuna. (C) 2008 Elsevier B.V. All rights reserved.
  • Takashi Maoka; Fumio Tanimoto; Mitsuhiko Sano; Kanji Tsurukawa; Takuo Tsuno; Satomi Tsujiwaki; Katsuya Ishimaru; Kenji Takii
    JOURNAL OF OLEO SCIENCE JAPAN OIL CHEMISTS SOC 57 (2) 133 - 137 1345-8957 2008/02 [Refereed]
     
    The effects of ferulic acid (FA) and gamma-oryzanol (OZ) supplementation on cultured red sea bream were examined. Commercial brown fish meal diets supplemented with FA (0.01-0.5%) or OZ (0.05-0.5%) were given to zero-year, cultured red sea bream for 98 days. After the experiment, the brightness of the integument color ("L" value) of FA- and OZ-administrated fish was higher than that of control fish. Furthermore, 2-Thiobarbituric acid reactive substances (TBARS) in the liver of FA- and OZ-administrated fish was lower than in control fish. These results indicate that FA and OZ suppressed not only dark-color pigmentation but also oxidative stress in cultured red sea bream.
  • Fumihito KATO; Katsuya ISHIMARU; Osamu MURATA; Hidemi KUMAI
    Aquaculture Science Japanese Society for Aquaculture Science 55 (1) 97 - 101 0371-4217 2007/03 [Refereed]
     
    Two strains, R2 from red sea bream and GF0609 from Japanese flounder, of Tenacibaculum maritimum, causative agents of gliding bacterial disease, were grown on modified cytophaga agar medium containing 70% seawater for 48 h at 25°C and were inactivated with 1.5% (v/v) formalin-PBS for 48 h at 4°C (FKC-R2 and FKC-GF) . To evaluate efficacies of the FKCs in red sea bream and Japanese flounder, fishes were immersion-vaccinated with each FKC (20μg wet weight/ml) for 20 min, and were experimentally challenged with the R2 and/or GF0609 strains at 10 days post vaccination. In the challenge by R2 strain, survival rates of vaccinated red sea bream with FKC-R2 and FKC-GF were 80% (RPS: 75%) and 40% (RPS: 25%), with a significant difference from that of control (P<0.05) . No vaccination efficacy of the FKCs was observed in Japanese flounder challenged by the GF0609. Moreover, susceptibilities of red sea bream against GF0609 and Japanese flounder against R2 were revealed to be low.
  • Seung-Cheol Ji; Osamu Takaoka; Gwan-Sik Jeong; Si-Woo Lee; Katsuya Ishimaru; Manabu Seoka; Kenji Takii
    FISHERIES SCIENCE BLACKWELL PUBLISHING 73 (1) 63 - 69 0919-9268 2007/02 [Refereed]
     
    The effects of dietary medicinal herbs on growth and some non-specific immunity were investigated in juvenile red sea bream Pagrus major. The fish (mean body weight 24.0 +/- 0.2 g) were fed fishmeal diets supplemented with either Massa medicata (Mm), Crataegi fructus (Cf), Artemisia capillaries (Ac), Cnidium officinale (Co), or a mixture of all the herbs (HM), and a control diet without medicinal herbs, for 12 weeks. Survival, specific growth rate, feed efficiency, condition factor and hemoglobin levels were higher in fish given herbal diets than fish given the control diet without herbs. Significantly higher serum high density lipoprotein-cholesterol level and lysozyme activity were detected in HM and Co diet groups, and alternative complement pathway activity was detected in the HM diet group. However, significantly lower serum alanine aminotransferase and aspartate aminotransferase activities were obtained in all herbal diet groups compared with the control diet group. Pathogen challenge test by intraperitoneal injection of Vibrio anguillarum indicated that highest survival was obtained in the HM diet group followed by Ac, Co, Cf, and Mm diet groups. The lowest survival was obtained in the control group. These results reveal that medicinal herbs in diets enhance growth and some non-specific immunity of red sea bream.
  • Fumihito Kato; Katsuya Ishimaru; Osamu Murata; Hidemi Kumai
    NIPPON SUISAN GAKKAISHI JAPANESE SOC FISHERIES SCIENCE 73 (1) 51 - 54 0021-5392 2007/01 [Refereed]
     
    The efficacy of immersion-vaccination against gliding bacterial disease in red sea bream Pagrus major was examined with formalin killed cells (FKC) of Tenacibaculum maritimum. FKC was prepared from T maritimum type strain R2 grown on modified Cytophaga agar medium containing 70% sea water for 24 h at 25 degrees C by inactivating with 1.5% (v/v) formalin-PBS for 24 h at VC. In experiment 1, juvenile red sea bream immersion-vaccinated with FKC (20 mu g/mL) for 30 min were challenged with T maritimum R2 3 days, 1 and 2 weeks after vaccination. The survival rates of the groups challenged after I or 2 weeks were significantly higher than those of the control group (P < 0.05). In experiment II, a twice-vaccinated group was compared with once-vaccinated groups and control. The survival rates of all the vaccinated groups were significantly higher than that of the control (P < 0.05), and the twice-vaccinated group showed the highest survival rate.
  • Fumihito Kato; Katsuya Ishimaru; Osamu Murata; Hidemi Kumai
    Nippon Suisan Gakkaishi (Japanese Edition) 73 (1) 51 - 54 0021-5392 2007/01 [Refereed]
     
    The efficacy of immersion-vaccination against gliding bacterial disease in red sea bream Pagrus major was examined with formalin killed cells (FKC) of Tenacibaculum maritimum. FKC was prepared from T. maritimum type strain R2 grown on modified Cytophaga agar medium containing 70% sea water for 24 h at 25°C by inactivating with 1.5% (v/v) formalin-PBS for 24 h at 4°C. In experiment I, juvenile red sea bream immersion-vaccinated with FKC (20 μg/mL) for 30 min were challenged with T. maritimum R2 3 days, 1 and 2 weeks after vaccination. The survival rates of the groups challenged after 1 or 2 weeks were significantly higher than those of the control group (P< 0.05). In experiment II, a twice-vaccinated group was compared with once-vaccinated groups and control. The survival rates of all the vaccinated groups were significantly higher than that of the control (P< 0.05), and the twice-vaccinated group showed the highest survival rate.
  • Kohsuke ADACHI; Keitaro KATO; Kazumasa WAKAMATSU; Shosuke ITO; Katsuya ISHIMARU; Osamu MURATA; Hidemi KUMAI
    Aquqculture Science Japanese Society for Aquaculture Science 54 (1) 31 - 35 0371-4217 2006/03 [Refereed]
     
    Effects of low temperature on the color of red sea bream (Pagrus major) were investigated. In colorimetric evaluation using L*a*b* system the fish reared under low-temperature (10°C) for two months lost their L* value compared to control (bred under 22°C) while no change was observed in a* and b* value. No significant difference was found in blood test (GOT, GPT, ALP, gamma-GTP, total bilirubin, direct bilirubin, indirect bilirubin and bile acid) . We also examined the properties of the "yellowed" juvenile red seabream which sometimes occur in winter season in Fisheries Laboratory of Kinki University. The b* value was significantly lower than that of control while no significant difference could be found in L* value. The blood test showed no clear difference in direct and indirect bilirubin conc as well as in other measurements. We also examined the concentration of yellow melanin (pheomelanin), however, no significant gap could be found in nomal and yellowed red seabream, indicating that the cause of yellowness is not bilirubin and pheomelanin accumulation.
  • TAKII Kenji; ISHIMARU Katsuya; YOSHIDA Yukinori; INOUE Shuichi; HIDAKA Kumi; MAOKA Takashi; TANIMOTO Fumio; FUSHIKI Shozoh
    Bulletin of the Fisheries Laboratory of Kinki University Kinki University 10 (10) 11 - 18 0911-7628 2006 [Refereed]
     
    We investigated the effect of dietary yeast Hansenula anomala autolysate (Ha) for ayu Plecoglossus altivelis growth and disease resistance for streptococciosis infection. Chilean fishmeal diets supplemented with Ha at the levels of 18%, 9% and 3% were given on the fish weighing 35.7 g, 4 times daily, 6 days a week for 70 days. Moreover, consecutive feeding and daily alternative feeding protocols of 3%-Ha diet and/or a control diet 0% -Ha were conducted on the fish weighing 33.0 g for 50 days. Weight gains and feed efficiencies of the fish fed with 9% and 3%-Ha diet were similar and better than those with 18%-Ha and 0%-Ha diets. Peculiar streptococciosis symptoms due to natural infection with Streptococcus sp. were observed in the fish with Ha supplemented diets (71〜76%), slightly less than the fish on 0%-Ha (85%). The consecutive feeding and daily alternative feeding protocols with 3%-Ha diet induced higher growth rates than the consecutive feeding protocol with 0%-Ha diet. Moreover, the streptococciosis symptoms due to natural infection decreased in the daily alternative feeding protocol (28.6%), followed by consecutive feeding protocols with 0% Ha (45%) and 3%-Ha diets (50%), at the end of the feeding trial. These results suggest that dietary Ha supplement is an useful strategy for improving growth performance as well as disease resistance for Streptococcus sp. of ayu
  • K Adachi; K Kato; K Wakamatsu; S Ito; K Ishimaru; T Hirata; O Murata; H Kumai
    PIGMENT CELL RESEARCH BLACKWELL PUBLISHING 18 (6) 465 - 468 0893-5785 2005/12 [Refereed]
     
    Human melanocytes respond to UV irradiation by increasing the synthesis of melanin. While much is now understood of the pathways governing this process and the nature of the melanin synthesized, little is known of melanins produced by lower vertebrates and their capacity to respond to UV. Here we report that a fish, red seabream, can undergo 'suntanning'. Histological, colorimetric and chemical assays were performed for suntanned red seabream fish bred in net cages to analyse the melanins and compared with shaded or wild red seabream fish. For color evaluation, the L* values of suntanned fish were dramatically lower than those in the other two groups. Pyrrole-2,3,5-tricarboxylic acid (PTCA), an indicator of eumelanin, was detected in suntanned fish at five times higher levels than in shaded or wild fish while 4-amino-3-hydroxyphenyl-alanine (4-AHP), a marker for pheomelanin, could not be detected in any of the samples. Histological analysis showed that melanocytes in the suntanned skin enlarged and increased in number to form a monolayer at the surface of the skin. Analysis of L* values and PTCA levels showed quite a high correlation coefficient (r = -0.843). When comparing shaded and wild red seabream fish, the scores were closer but some significant differences were still found in some body areas. These results indicate that eumelanin accumulates in suntanned fish during the increase in skin color, which is induced by sunlight, presumably by ultraviolet radiation.
  • K Kato; K Ishimaru; Y Sawada; J Mutsuro; S Miyashita; O Murata; H Kumai
    FISHERIES SCIENCE SPRINGER TOKYO 70 (6) 1061 - 1069 0919-9268 2004/12 [Refereed]
     
    A histological examination was made of the ontogenetic development of the digestive and immune systems of the larval and juvenile kelp grouper Epinephelus bruneus reared in the laboratory The liver, gall bladder, pancreas and the demarcating region between the intestines and rectum were formed within 3 days post-hatch (dph). During the preflexion phase (within 16 dph), revolution of the intestine concluded, and pharyngeal teeth and the mucous cells of the esophagus were differentiated. In the transitional period to the juvenile stage (25 dph), the blind sac of the stomach, gastric glands and pyloric caeca began to form. From the viewpoint of the differentiation phase of the adult-type digestive system, the kelp grouper is similar to Heterosomata, hitherto reported. The primordial thymus, kidney and spleen were present at 12, 1 and 6 dph, and the small lymphocytes in these lymphoid organs appeared at 21, 30 and 33 dph, respectively The developmental sequence of the lymphoid organs and the appearance ages of the lymphoid organs and small lymphocytes in the lymphoid organs in the kelp grouper are similar to those of other marine fish previously reported, except for the Pacific bluefin tuna Thunnus orientalis.
  • イシダイ仔稚魚の腸内細菌相
    石丸克也; 山本眞司; 村田修; 熊井英水
    近畿大学水産研究所報告 (7) 35 - 42 2000/03
  • K Ishimaru; K Muroga
    FISH PATHOLOGY JAPAN SOC FISH PATHOL DEPT FISHERIES-FAC AGR 32 (1) 59 - 64 0388-788X 1997/03 [Refereed]
     
    A taxonomical re-examination of two pathogenic bacteria belonging to the genus Vibrio, one from an eye disease of milkfish (Chanos chanos) in the Philippines and the other from vibriosis of larval swimming crab (Portunus trituberculatus) in Japan, was made by examining their phenotypic features and measuring DNA-DNA relatedness. As a result, the bacterium from milkfish was identified as V. harveyi based on the high DNA homology value of above 84% between the two milkfish isolates and the type strain of V. harveyi and coincidence in phenotypic characteristics. Strain 85Z-1, the representative strain of the causative bacterium (Vibrio sp. Zoea) of vibriosis in swimming crab, showed higher DNA relatedness than 75% to other 3 strains of Vibrio sp. Zoea, about 50% relatedness to strains of V. harveyi, and lower relatedness than 46% to the other species examined. These results indicate that Vibrio sp. Zoea is a new genomic species most closely to V, harveyi. However, it is difficult to distinguish phenotypically Vibrio sp. Zoea from V, harveyi isolated from milkfish, thus species name for Vibrio sp. Zoea could not be proposed.
  • Katsuya Ishimaru; Kiyokuni Muroga
    Fish Pathology Japanese Society of Fish Pathology 32 (1) 59 - 64 0388-788X 1997 [Refereed]
     
    A taxonomical re-examination of two pathogenic bacteria belonging to the genus Vibrio, one from an eye disease of milkfish (Chanos chanos) in the Philippines and the other from vibriosis of larval swimming crab (Portunus trituberculatus) in Japan, was made by examining their phenotypic features and measuring DNA-DNA relatedness. As a result, the bacterium from milkfish was identified as V. harveyi based on the high DNA homology value of above 84% between the two milkfish isolates and the type strain of V. harveyi and coincidence in phenotypic characteristics. Strain 85Z-1, the representative strain of the causative bacterium (Vibrio sp. Zoea) of vibriosis in swimming crab, showed higher DNA relatedness than 75% to other 3 strains of Vibrio sp. Zoea, about 50% relatedness to strains of V. harveyi, and lower relatedness than 46% to the other species examined. These results indicate that Vibrio sp. Zoea is a new genomic species most closely to V. harveyi. However, it is difficult to distinguish phenotypically Vibrio sp. Zoea from V. harveyi isolated from milkfish, thus species name for Vibrio sp. Zoea could not be proposed.
  • K Ishimaru; M AkagawaMatsushita; K Muroga
    INTERNATIONAL JOURNAL OF SYSTEMATIC BACTERIOLOGY AMER SOC MICROBIOLOGY 46 (1) 155 - 159 0020-7713 1996/01 [Refereed]
     
    Seven similar strains which were pathogens of Japanese flounder (Paralichthys olivaceus) larvae with opaque intestines had characteristics of the genus Vibrio, These strains were divided into two genomic species (species 1 containing six strains, and species 2 containing one strain) on the basis of the results of DNA-DNA hybridization experiments in which the membrane filter method was used, and these two species could be differentiated from each other by the following characteristics: acid production from D-galactose and utilization of D-glucuronate and P-hydroxybutyrate, Strain F-2, the type strain of species 1, exhibited levels of DNA relatedness with 29 previously described Vibrio species of 5 to 18%, The flounder isolates belonging to species 1 were also differentiated from the previously described Vibrio species phenotypically by the following characteristics: they were nitrate reduction positive; each cell had a single polar flagellum; they did not produce arginine dihydrolase, chitinase, gelatinase, and lipase; they did not utilize D-cellobiose and citrate; and they did not grow at 35 degrees C, The G+C contents of the DNAs of four species 1 strains were 43 to 44 mol%, The name Vibrio ichthyoenteri sp. nov. is proposed for genomic species 1. The type strain of V. ichthyoeenteri is strain F-2 (= IFO 15847), Species 2 was also considered a new genomic species, but a species name is not proposed in this paper because only one strain is available and the phenotypic variability of the species is not known.
  • K ISHIMARU; M AKAGAWAMATSUSHITA; K MUROGA
    INTERNATIONAL JOURNAL OF SYSTEMATIC BACTERIOLOGY AMER SOC MICROBIOLOGY 45 (1) 134 - 138 0020-7713 1995/01 [Refereed]
     
    Six similar strains which were isolated as pathogens of cultured kuruma prawns (Penaeus japonicus) in Japan had characteristics of the genus Vibrio. These organisms were distinguished from previously described Vibrio species by their positive results in tests for gelatinase and lipase activities and their negative reactions in tests for arginine dihydrolase and lysine and ornithine decarboxylase activities, growth in the presence of 6% NaCl and at 35 degrees C, acid production from sucrose, utilization of D-glucuronate and propionate, and luminescence. The G+C contents of the DNAs of these organisms were 46.2 to 47.0 mol%, The levels of DNA relatedness among these six strains were 87 to 99% (as determined by the membrane filter method), while the levels of DNA relatedness between prawn pathogen strain KH-1(T) (T type strain) and members of 28 previously described Vibrio species were less than 18%, The name Vibrio penaeicida sp, nov, is proposed for the prawn-pathogenic strains, The type strain is strain KH-1 (= IFO 15640 = JCM 9123).
  • Kiyokuni Muroga; Kouji Sszuik; Katsuya Ishimaru; Kinya Nogami
    Journal of the World Aquaculture Society 25 (1) 50 - 54 1749-7345 1994 [Refereed]
     
    Since 1985, frequent mass mortalities due to a bacterial infection have occurred in zoeal larvae of swimming crab Portunus trituberculatus reared at the Tamano Station of the Japan Sea‐Farming Association. A bacterium was predominantly isolated from diseased larvae and was demonstrated by experimental infection to be the causative agent of the disease. Based on morphological, physiological, biochemical, serological and genetic characteristics of the pathogen, it was thought to be a new species and tentatively named Vibrio sp. Zoea. Challenge experiments with the bacterium in several aquatic animals indicate that Vibrio sp. Zoea appears to be a pathogen specific for crustaceans. Copyright © 1994, Wiley Blackwell. All rights reserved

Conference Activities & Talks

  • クロマグロ仔稚魚の腸内細菌相  [Not invited]
    熊井 英水; 石丸 克也; 村田 修; 宮下 盛
    2004/04
  • ブリα溶血性レンサ球菌症ワクチンの実験的免疫持続効果試験  [Not invited]
    熊井 英水; 石丸 克也; 村田 修; 中平有哉; 一ノ瀬弘幸; 佐々木英治
    2003/04
  • マンノクリーンβ（酵素処理ヤシ粕）経口投与による海産白点病の寄生軽減  [Not invited]
    石丸 克也; 福井 健介; 吉田 靖彦; 伊吹 昌久
    平成29年度日本魚病学会春季大会

MISC

Research Grants & Projects

  • 日本学術振興会：科学研究費助成事業
    Date (from‐to) : 2021/04 -2024/03 
    Author : 楠本 晃子; 石丸 克也; 中井 敏博
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research
    Date (from‐to) : 2010 -2012 
    Author : OGAWA Kazuo; YOSHINAGA Tomoyoshi; SAWADA Yoshifumi; ISIMARU Katsuya; SHIRAKASHI Sho
     
    Firstly, a second blood fluke species from Pacific bluefin tuna was found from the heart ventricle and described as Cardicola opisthorchis n. sp. Secondly, new methods were developed to distinguish eggs of C. orientalis from those of C. opisthorchis morphologically, and to count the number of eggs in the gills. Thirdly, infection cycle was partly elucidated. Namely, both species of blood flukes were found in juvenile tuna 45 days after transfer to outside net cages; one week later, flukes were matured and laid eggs after one more week. Fourthly, C. opisthorchis was eradicated from tuna with oral administration of praziquantel (PZQ) at 7.5 mg/kg fish body weight or more for 3 consecutive days. Reinfection was confirmed 1 month after medication. PZQ concentration in tuna decreased to the undetectable level（0.02 μg/L）24 h after administration. Lastly, SEM observation of the two species of blood flukes shows swelling and contraction of the tegument and formation of many minute furrowed ridges in C. opisthorchis, while in C. orientalis, many minute holes were characteristically formed on the tegument.

Other link

researchmap


Copyright © MEDIA FUSION Co.,Ltd. All rights reserved.