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Nakayama K, Obayashi Y, Munechika L, Kitamura SI, Yanagida T, Honjo M, Murakami S, Hirose E. Regeneration of tunic cuticle is suppressed in edible ascidian Halocynthia roretzi contracting soft tunic syndrome. DISEASES OF AQUATIC ORGANISMS 2024; 159:37-48. [PMID: 39087618 DOI: 10.3354/dao03801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/02/2024]
Abstract
Soft tunic syndrome is an infectious disease caused by the flagellate Azumiobodo hoyamushi, which severely damages the aquaculture of the edible ascidian Halocynthia roretzi. Tunic is a cellulosic extracellular matrix entirely covering the body in ascidians and other tunicates, and its dense cuticle layer covers the tunic surface as a physical barrier against microorganisms. When the tunic of intact H. roretzi individuals was cut into strips, electron-dense fibers (DFs) appeared on the cut surface of the tunic matrix and aggregated to regenerate a new cuticular layer in seawater within a few days. DF formation was partially or completely inhibited in individuals with soft tunic syndrome, and DF formation was also inhibited by the presence of some proteases, indicating the involvement of proteolysis in the process of tunic softening as well as cuticle regeneration. Using pure cultures of the causative flagellate A. hoyamushi, the expression of protease genes and secretion of some proteases were confirmed by RNA-seq analysis and a 4-methylcoumaryl-7-amide substrate assay. Some of these proteases may degrade proteins in the tunic matrix. These findings suggest that the proteases of A. hoyamushi is the key to understanding the mechanisms of cuticular regeneration inhibition and tunic softening.
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Affiliation(s)
- Kei Nakayama
- Center for Marine Environmental Studies (CMES), Ehime University, Matsuyama, Ehime, 790-8577, Japan
| | - Yumiko Obayashi
- Center for Marine Environmental Studies (CMES), Ehime University, Matsuyama, Ehime, 790-8577, Japan
| | - Leo Munechika
- Center for Marine Environmental Studies (CMES), Ehime University, Matsuyama, Ehime, 790-8577, Japan
| | - Shin-Ichi Kitamura
- Graduate School of Bioresources, Mie University, 1577 Kurimamachiya-cho, Tsu, Mie, 514-8507, Japan
| | - Tetsuya Yanagida
- Joint Faculty of Veterinary Medicine, Yamaguchi University, Yamaguchi, 753-8515, Japan
| | - Miho Honjo
- Miyagi Prefecture Fisheries Technology Institute, Ishinomaki, Miyagi, 986-2135, Japan
| | - Shoko Murakami
- Center for Marine Environmental Studies (CMES), Ehime University, Matsuyama, Ehime, 790-8577, Japan
| | - Euichi Hirose
- Department of Chemistry, Biology, and Marine Science, Faculty of Science, University of the Ryukyus, Okinawa, 903-0213, Japan
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Lee WJ, Kim GJ. Gonadal Changes during the Annual Reproductive Cycle of the Ascidian
Halocynthia aurantium (Pallas). Dev Reprod 2021; 25:299-303. [PMID: 35141455 PMCID: PMC8807128 DOI: 10.12717/dr.2021.25.4.299] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2021] [Revised: 10/16/2021] [Accepted: 11/19/2021] [Indexed: 11/21/2022]
Abstract
The ascidian Halocynthia aurantium (sea peach), a marine
invertebrate, belongs to the same genus of the phylum Chordata along with the
ascidian Halocynthia roretzi (sea pineapple), which is one of
the model animals in the field of developmental biology. The characteristics of
development and reproduction of H. aurantium are not yet known
in detail. In order to find out the spawning period of H.
aurantium, we investigated development of the gonads during the
annual reproductive cycle. Testis and ovary were both in the bisexual gonads
(ovotestes) of H. aurantium, which is a hermaphrodite like
H. roretzi. In H. aurantium, the right
gonad was longer and slightly larger than the left gonad throughout the year. In
each gonad, the number of the testis gonoducts was slightly higher than that of
the ovary gonoducts. These features were similarly observed in H.
roretzi. However, the number of the testis gonoducts and the ovary
gonoducts in each gonad of H. aurantium was about half that of
H. roretzi. The gonads of H. aurantium
contracted during the winter and summer seasons. The gonads decreased to the
smallest size around February, and then started to increase again in March. The
gonads were most developed in September of the year. Therefore, it is estimated
that the spawning of H. aurantium begins around this
period.
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Affiliation(s)
- Wang Jong Lee
- Dept. of Marine Molecular Bioscience,
Gangneung-Wonju National University, Gangneung
25457, Korea
| | - Gil Jung Kim
- Dept. of Marine Molecular Bioscience,
Gangneung-Wonju National University, Gangneung
25457, Korea
- Corresponding author Gil Jung Kim, Dept. of
Marine Molecular Bioscience, Gangneung-Wonju National University, Gangneung
25457, Korea. Tel: +82-33-640-2415, Fax:
+82-33-640-2849, E-mail:
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Marquis ND, Bishop TJ, Record NR, Countway PD, Fernández Robledo JA. A qPCR-Based Survey of Haplosporidium nelsoni and Perkinsus spp. in the Eastern Oyster, Crassostrea virginica in Maine, USA. Pathogens 2020; 9:E256. [PMID: 32244534 PMCID: PMC7238206 DOI: 10.3390/pathogens9040256] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Revised: 03/28/2020] [Accepted: 03/30/2020] [Indexed: 12/11/2022] Open
Abstract
Eastern oyster (Crassostrea virginica) aquaculture is increasingly playing a significant role in the state of Maine's (USA) coastal economy. Here, we conducted a qPCR-based survey for Haplosporidium nelsoni, Perkinsus marinus, and Perkinsus chesapeaki in C. virginica (n = 1440) from six Maine sites during the summer-fall of 2016 and 2017. In the absence of reported die-offs, our results indicated the continued presence of the three protozoan parasites in the six sites. The highest H. nelsoni qPCR-prevalence corresponded to Jack's Point and Prentiss Island (x=40 and 48% respectively), both located in the Damariscotta River Estuary. Jack's Point, Prentiss Island, New Meadows River, and Weskeag River recorded the highest qPCR-prevalence for P. marinus (32-39%). While the P. marinus qPCR-prevalence differed slightly for the years 2016 and 2017, P. chesapeaki qPCR-prevalence in 2016 was markedly lower than 2017 (<20% at all sites versus >60% at all sites for each of the years, respectively). Mean qPCR-prevalence values for P. chesapeaki over the two-year study were ≥40% for samples from Jack's Point (49%), Prentiss Island (44%), and New Meadows River (40%). This study highlights that large and sustained surveys for parasitic diseases are fundamental for decision making toward the management of the shellfish aquaculture industry, especially for having a baseline in the case that die-offs occur.
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Affiliation(s)
- Nicholas D. Marquis
- Bigelow Laboratory for Ocean Sciences, Boothbay, ME 04544, USA; (N.D.M.); (T.J.B.); (N.R.R.); (P.D.C.)
| | - Theodore J. Bishop
- Bigelow Laboratory for Ocean Sciences, Boothbay, ME 04544, USA; (N.D.M.); (T.J.B.); (N.R.R.); (P.D.C.)
- Department of Marine Sciences, Southern Maine Community College, South Portland, ME 04106, USA
| | - Nicholas R. Record
- Bigelow Laboratory for Ocean Sciences, Boothbay, ME 04544, USA; (N.D.M.); (T.J.B.); (N.R.R.); (P.D.C.)
| | - Peter D. Countway
- Bigelow Laboratory for Ocean Sciences, Boothbay, ME 04544, USA; (N.D.M.); (T.J.B.); (N.R.R.); (P.D.C.)
| | - José A. Fernández Robledo
- Bigelow Laboratory for Ocean Sciences, Boothbay, ME 04544, USA; (N.D.M.); (T.J.B.); (N.R.R.); (P.D.C.)
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Hirose E, Nakayama K, Yanagida T, Nawata A, Kitamura SI. Measurement of Tunic Hardness in an Edible Ascidian, Halocynthia roretzi, with Remarks on Soft Tunic Syndrome. Zoolog Sci 2018; 35:548-552. [DOI: 10.2108/zs180072] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Affiliation(s)
- Euichi Hirose
- Department of Chemistry, Biology, and Marine Science, Faculty of Science, University of the Ryukyus, Okinawa 903-0213, Japan
| | - Kei Nakayama
- Center for Marine Environmental Studies (CMES), Ehime University, Matsuyama, Ehime 790-8577, Japan
| | - Tetsuya Yanagida
- Joint Faculty of Veterinary Medicine, Yamaguchi University, Yamaguchi 753-8515, Japan
| | - Akatsuki Nawata
- Miyagi Prefecture Fisheries Technology Institute, Ishinomaki, Miyagi 986-2135, Japan
| | - Shin-Ichi Kitamura
- Center for Marine Environmental Studies (CMES), Ehime University, Matsuyama, Ehime 790-8577, Japan
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Nawata A, Hirose E, Kitamura SI. Tunic extract of the host ascidian attracts the causal agent of soft tunic syndrome, Azumiobodo hoyamushi (Kinetoplastea: Neobodonida). DISEASES OF AQUATIC ORGANISMS 2018; 129:207-214. [PMID: 30154281 DOI: 10.3354/dao03253] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Azumiobodo hoyamushi, a kinetoplastid flagellate, is the causative agent of soft tunic syndrome, an infectious disease of the edible ascidian Halocynthia roretzi. The flagellate is thought to invade the tunic matrix via a damaged area of the tunic on the siphon wall. We hypothesized that the flagellate locates the tunic entry site by a chemotactic response to soluble substances diffused from the host ascidians. To investigate this hypothesis, we examined whether the flagellate shows a chemotactic response to tissue extracts (tunic and other tissues) from the host ascidian H. roretzi. We tested extracts from 5 tissues as well as hemolymph. Only the tunic extract showed significant positive chemotactic activity, and the activity decreased with increasing dilution. Furthermore, autoclaved tunic extract, extracts from diseased individuals, and extract from the styelid ascidian Styela clava also had chemotactic activity, although the activities were lower than that of tunic extract from healthy H. roretzi. Ultrafiltration of the tunic extract through a 3 kDa cutoff membrane completely abrogated the activity; the ultrafiltration retentate still showed activity. Thus, the soluble factors that attract the flagellate are present exclusively in the tunic extract, and the chemotactic factors are larger than 3 kDa. Our experiments also suggested that the tunic extract contains both heat-stable and heat-labile factors. We conclude that the flagellate locates the tunic entry site by chemotaxis toward soluble factors that diffuse from a damaged area of the tunic on the siphon wall.
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Affiliation(s)
- Akatsuki Nawata
- Miyagi Prefecture Fisheries Technology Institute, Ishinomaki, Miyagi 986-2135, Japan
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Goodwin JD, Lee TF, Kugrens P, Simpson AGB. Allobodo chlorophagus n. gen. n. sp., a Kinetoplastid that Infiltrates and Feeds on the Invasive Alga Codium fragile. Protist 2018; 169:911-925. [PMID: 30445354 DOI: 10.1016/j.protis.2018.07.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2018] [Revised: 07/21/2018] [Accepted: 07/24/2018] [Indexed: 11/24/2022]
Abstract
A novel biflagellate protist that consumed chloroplasts inside material of the invasive marine green alga Codium fragile was reported from the U.S. east coast in 2003. We observed a similar association in C. fragile from five sites in Nova Scotia, Canada during 2013 and 2014. After incubating Codium fragments for 2-3 days, some utricles and filaments contained numerous chloroplast-consuming cells. Transmission electron microscopy (TEM) confirmed that these were kinetoplastids with a pankinetoplast, large electron-dense droplets in the cytoplasm and a connective between the paraxonemal rod bases, but no conspicuous para-cytopharyngeal rod, all consistent with U.S. material observed in 2003. The ITS1-5.8S rRNA-ITS2 sequences from 13 Nova Scotia isolates were identical. SSU rRNA gene phylogenies placed the Codium-associated kinetoplastid in neobodonid clade '1E'. Clade 1E likely contains no previously described species, and branches outside all other major neobodonid groups, either as their sister or as a separate lineage, depending on rooting. These results indicate that the kinetoplastid represents a single species that merits a new genus (and family), and we describe it as Allobodo chlorophagus n. gen., n. sp. The lack of evidence for food sources other than Codium is consistent with a parasitic association, but other possibilities exist (e.g. necrotrophy).
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Affiliation(s)
- Joshua D Goodwin
- Department of Biology, and Centre for Comparative Genomics and Evolutionary Bioinformatics, Dalhousie University, Halifax B3H 4R2, Canada
| | | | | | - Alastair G B Simpson
- Department of Biology, and Centre for Comparative Genomics and Evolutionary Bioinformatics, Dalhousie University, Halifax B3H 4R2, Canada.
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Kumagai A, Tanabe T, Nawata A, Suto A. Disinfection of fertilized eggs of the edible ascidian Halocynthia roretzi for prevention of soft tunic syndrome. DISEASES OF AQUATIC ORGANISMS 2016; 118:153-158. [PMID: 26912045 DOI: 10.3354/dao02966] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Azumiobodo hoyamushi, the causative agent of soft tunic syndrome, was likely introduced to farming sites of the edible ascidian Halocynthia roretzi via ascidian spat. The source of infection is thought to be cysts of A. hoyamushi that reside in the substrates on which the ascidian spat are attached, but not the spat themselves. Thus, there is a need to develop methods to prevent contamination of the substrates with A. hoyamushi during seed production of the ascidian. We evaluated the protozoacidal effects of sodium hypochlorite and povidone-iodine against the flagellate and temporary cyst forms of A. hoyamushi. Additionally, we evaluated the effects of these disinfectants on the development of fertilized ascidian eggs. The flagellate form of A. hoyamushi was completely inactivated by povidone-iodine (5 ppm, 1 min) and sodium hypochlorite (1 ppm, 1 min). The temporary cysts of A. hoyamushi were completely inactivated by both disinfectants (5 ppm, 1 min). Disinfection with 50 ppm povidone-iodine for 15 min or 5 ppm sodium hypochlorite for 15 min had no effect on ascidian embryogenesis. Thus, horizontal transmission of A. hoyamushi via the substrates can be efficiently prevented by disinfecting ascidian eggs or tools used for spawning with povidone-iodine baths ranging from 5 ppm for 1 min to 50 ppm for 15 min without any side effects.
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Affiliation(s)
- Akira Kumagai
- Miyagi Prefecture Fisheries Technology Institute, Kesennuma Fisheries Experimental Station, Kesennuma, Miyagi 988-0181, Japan
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Nam KW, Shin YK, Park KI. Seasonal variation in Azumiobodo hoyamushi infection among benthic organisms in the southern coast of Korea. Parasit Vectors 2015; 8:569. [PMID: 26531210 PMCID: PMC4632471 DOI: 10.1186/s13071-015-1179-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Accepted: 10/23/2015] [Indexed: 11/24/2022] Open
Abstract
Background Recent studies have reported that soft tunic syndrome (STS) in the edible ascidian Halocynthia roretzi is caused by the kinetoplastid parasite Azumiobodo hoyamushi. In this study, we attempted to detect and quantify the pathogen in benthic animals. Methods Four species of ascidians, three species of echinoderms, two species of bivalves, one species each of sponge and algae, as well as seawater, were collected in 2014 and 2015 from an ascidian farm on the southern coast of Korea by SCUBA diving. Samples were collected from ascidian hanging culture ropes or the sea bottom. Inhalent siphons were excised for the analysis of ascidians, and soft body tissues were excised from the other species. Membrane filters were used to filter collected seawater. Tissues and membrane filters were analysed using culture testing, PCR testing, and qPCR diagnoses. Results Only organisms belonging to Ascidiacea are susceptible to A. hoyamushi infection. The infection rate (% infected of the total number collected) and infection intensity (number of cells infected/g tissue wet weight) varied depending on the seasonal variation in seawater temperatures. Most ascidians examined were infected with A. hoyamushi and showed higher infection intensity in cold water seasons (April 2014 and February 2015), followed by a dramatic drop during warm water seasons (August and November, 2014). In addition, infection intensity of A. hoyamushi during the warm water period was higher in ascidians from the sea bottom than those from the hanging culture rope. Conclusions Among benthic organisms that inhabit the southern coast of Korea, most ascidians are susceptible to A. hoyamushi infection. Seasonal cycle of infection rates and intensities of the pathogen correspond well with the STS disappearance and onset cycle observed in ascidian farms. The high intensity of A. hoyamushi infection in the ascidians on the sea bottom of ascidian farms during summer suggest further studies on the role of the pathogen in resumption of STS occurrence in late fall or early winter in the southern coast of Korea.
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Affiliation(s)
- Ki-Woong Nam
- Department of Aquatic Life Medicine, College of Ocean Science and Technology, Kunsan National University, 558 Daehakno, Gunsan, 573-701, Republic of Korea.
| | - Yun-Kyung Shin
- National Fisheries Research Institute, Busan, 619-705, Republic of Korea.
| | - Kyung-Il Park
- Department of Aquatic Life Medicine, College of Ocean Science and Technology, Kunsan National University, 558 Daehakno, Gunsan, 573-701, Republic of Korea.
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Nawata A, Hirose E, Kitamura SI, Kumagai A. Encystment and excystment of kinetoplastid Azumiobodo hoyamushi, causal agent of soft tunic syndrome in ascidian aquaculture. DISEASES OF AQUATIC ORGANISMS 2015; 115:253-262. [PMID: 26290510 DOI: 10.3354/dao02897] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Soft tunic syndrome in the edible ascidian Halocynthia roretzi is caused by the kinetoplastid flagellate Azumiobodo hoyamushi, which was found to assume a fusiform cell form with 2 flagella in axenic, pure culture. When the flagellate form was incubated in sterilized artificial seawater (pH 8.4), some of the cells became cyst-like and adhered to the bottom of the culture plate. The cyst-like forms were spherical or cuboidal, and each had 2 flagella encapsulated in its cytoplasm. Encystment was also induced in culture medium alkalified to the pH of seawater (8.4) but not in unmodified (pH 7.2) or acidified media (pH 6.4). More than 95% of the cyst-like cells converted to the flagellate form within 1 d following transfer to seawater containing ascidian tunic extracts from host ascidians. The cyst-like cells were able to survive in seawater with no added nutrients for up to 2 wk at 20°C and for a few months at 5 to 15°C. The survival period in seawater depended on temperature: some cyst-like cells survived 3 mo at 10°C, and ca. 95% of these converted to flagellate forms in seawater containing tunic extracts. Thus, A. hoyamushi is able to persist under adverse conditions in a cyst-like form able to adhere to organic and inorganic substrata for protracted periods of time.
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Affiliation(s)
- Akatsuki Nawata
- Miyagi Prefecture Fisheries Technology Institute, Ishinomaki, Miyagi 986-2135, Japan
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Abstract
SUMMARYParasites have a major impact on global finfish and shellfish aquaculture, having significant effects on farm production, sustainability and economic viability. Parasite infections and impacts can, according to pathogen and context, be considered to be either unpredictable/sporadic or predictable/regular. Although both types of infection may result in the loss of stock and incur costs associated with the control and management of infection, predictable infections can also lead to costs associated with prophylaxis and related activities. The estimation of the economic cost of a parasite event is frequently complicated by the complex interplay of numerous factors associated with a specific incident, which may range from direct production losses to downstream socio-economic impacts on livelihoods and satellite industries associated with the primary producer. In this study, we examine the world's major marine and brackish water aquaculture production industries and provide estimates of the potential economic costs attributable to a range of key parasite pathogens using 498 specific events for the purposes of illustration and estimation of costs. This study provides a baseline resource for risk assessment and the development of more robust biosecurity practices, which can in turn help mitigate against and/or minimise the potential impacts of parasite-mediated disease in aquaculture.
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Shin YK, Nam KW, Park KH, Yoon JM, Park KI. Quantitative assessment of Azumiobodo hoyamushi distribution in the tunic of soft tunic syndrome-affected ascidian Halocynthia roretzi using real-time polymerase chain reaction. Parasit Vectors 2014; 7:539. [PMID: 25425505 PMCID: PMC4253000 DOI: 10.1186/s13071-014-0539-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2014] [Accepted: 11/13/2014] [Indexed: 11/10/2022] Open
Abstract
Background The kinetoplastid parasite, Azumiobodo hoyamushi, is the causative agent of soft tunic syndrome (STS) in ascidians and leads to their mass mortality in Korean waters. This study was conducted to quantify A. hoyamushi density during the development of STS in the tunics of ascidians (Halocynthia roretzi) using real-time polymerase chain reaction (qPCR). Findings The infection intensity of A. hoyamushi, as measured by qPCR, varied depending on the part of the tunic analyzed, as well as the stage of STS development. The highest infection intensity was recorded in the tunics of the siphons. The infection intensity of A. hoyamushi in the siphons was only 2.9 cell/tunic (area, 0.25 cm2) or 106.0 cell/gram tunic (GT) in the early phase of STS, but this value increased dramatically to 16,066 cells/tunic (0.25 cm2) or 617,004 cell/GT at the time of death. The number of A. hoyamushi parasites increased gradually and their distribution spread from the siphons to the other parts of the tunics. Conclusions qPCR enabled the quantitation of A. hoyamushi and the results revealed that parasite density increased as STS progressed. In addition, our results suggested that the siphons might function as the portal of entry for A. hoyamushi during infection.
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Affiliation(s)
- Yun-Kyung Shin
- National Fisheries Research and Development Institute, Busan, 619-705, Republic of Korea.
| | - Ki-Woong Nam
- Department of Aquatic Life Medicine, College of Ocean Science and Technology, Kunsan National University, 558 Daehakno, Gunsan, 573-701, Republic of Korea.
| | - Kwan Ha Park
- Department of Aquatic Life Medicine, College of Ocean Science and Technology, Kunsan National University, 558 Daehakno, Gunsan, 573-701, Republic of Korea.
| | - Jong-Man Yoon
- Department of Aquatic Life Medicine, College of Ocean Science and Technology, Kunsan National University, 558 Daehakno, Gunsan, 573-701, Republic of Korea.
| | - Kyung-Il Park
- Department of Aquatic Life Medicine, College of Ocean Science and Technology, Kunsan National University, 558 Daehakno, Gunsan, 573-701, Republic of Korea.
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