• Journal of Marine Life Science
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• v.2 no.2
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• pp.83-89
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• 2017

In abalones, interspecific hybridization has been suggested as a possible means to increase production and desired traits for the industry. In Korea, Haliotis gigantea is considered a species with a larger size and higher temperature tolerance than H. discus hannai. However, H. discus hannai is considered the most valuable and popular fishery resource due to its better acceptance and higher market prices. Thus, viable interspecific hybrids have been produced by artificial inseminating H. gigantea eggs with H. discus hannai sperm. However, the reciprocal hybrid cross was not successful. In this study, the hybridity and the growth and thermal tolerance performance of the interspecific hybrids were examined. A combination of various assays revealed maximum growth occurrence at 21℃ and the higher growth rate in the hybrids than that of H. discus hannai parent. In addition, the growth and survival at high-temperature (28℃) of the hybrids was equivalent to that of the highly tolerant H. gigantea parent, suggesting new possibilities to overcome the mass mortality in H. discus hannai during high temperature periods of summer season in Korea. Furthermore, the induced interspecific hybrid status was confirmed by the presence of species-specific bands for each parental species of the random amplified polymorphic DNA (RAPD) profiles using universal rice primer (URP), which could be used as speciesspecific markers to distinguish the hybrids and their parental species.

• Journal of Marine Life Science
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• v.8 no.1
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• pp.56-67
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• 2023

Marine macroalgae are important in coastal ecosystems and interact with marine microorganisms. In this study, we isolated fungi from seven types of marine macroalgae including Cladophora sp., Gloiopeltis furcate, Gracilariopsis chorda, Hydroclathrus clathratus, Prionitis crispata, Sargassum micracanthum, and Ulva lactuca collected in Korea. Morphological and phylogenetic analyses identified the isolates as four Aspergillus spp. (A. fumigatus, A. sydowii, A. tamarii, and A. terreus), three Penicillium spp. (P. crustosum, P. jejuense, and P. rubens), and Cladosporium tenuissimum. Among them, A. fumigatus TOP-U2, A. tamarii SH-Sw5, and A. terreus GJ-Gf2 strains showed the activities of all enzymes examined (amylase, chitinase, lipase, and protease). Based on the enzymatic index (EI) values in solid media, A. terreus GJ-Gf2 and C. tenuissimum UL-Pr1 exhibited the highest amylase and lipase activities, respectively. Chitinolytic activity was only observed in A. terreus GJ-Gf2, A. tamarii SH-Sw5, and A. fumigatus TOP-U2. Penicillium crustosum UL-Cl2 and C. tenuissimum UL-Pr1 showed the highest protease activities. To the best of our knowledge, this is the first report of lipolytic and proteolytic activities in a marine-derived C. tenuissimum strain. Overall, the fungal strains isolated from the marine macroalgae in this study actively produced industrially important enzymes.

• Fisheries and Aquatic Sciences
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• v.22 no.11
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• pp.27.1-27.6
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• 2019

Background: In order to assess the high value-added use of the alginate-free residue of sea tangle, an animal study was performed to evaluate the functional activities and key compounds present. In the animal study, sea tangle and the alginate-free residue demonstrated good anti-hyperlipidemic and anti-arteriosclerotic abilities. Results: The functional compounds in the alginate-free residue of the sea tangle were effectively extracted by supercritical fluid extraction (SFE). The optimum extraction temperature and pressure were 40 ℃ and 6500 psi (M1) in the SFE, a better method in comparison to the conditions of 70 ℃ and 4500 psi (M2), respectively. The anti-atherosclerotic effects of the alginate-free residue of sea tangle (M1, M2) were investigated in Sprague-Dawley rats treated with poloxamer 407, Triton WR 1339, corn oil, and a high-fat diet. The M1 fraction reduced the serum lipid levels with greater efficacy than the M2 fraction. In the hyperlipidemic rats, treatment with M1 decreased the serum triglyceride (TG), total cholesterol (TC), and low-density lipoprotein-cholesterol (LDL-C) levels when compared to the levels in normal rats. Conclusion: Our results demonstrated that the alginate-free residue of sea tangle reduces serum TC, TG, and LDL-C. These results suggest that the alginate-free residue of sea tangle contains physiologically active components, such as fucosterol, that may exert beneficial effects in the prevention of atherosclerosis.

• Korean Circulation Journal
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• v.53 no.1
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• pp.47-48
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• 2023

• Journal of Species Research
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• v.6 no.3
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• pp.241-257
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• 2017

After the first record of a Korean ciliate in 1931, more than 130 papers have been published describing Korean ciliates. Of these records, the years 1997, 2012, and 2016 include milestone publications in Korea. Even though the publications provide summarized data about Korean ciliates with relevant literature citations, these publications included two nomenclatural errors, two misspellings, and one misidentification; nine species were transferred to other genera. Furthermore, the type specimens deposited in the laboratory of Prof. Joong Ki Choi (Inha University, Korea) were transferred to the National Marine Biodiversity Institute of Korea (MABIK) because of his retirement. Here, we provide an updated list of 331 Korean species described by 2016 and present information about the type specimens. We also and address the aforementioned problems with bringing together scattered data related to ciliate lists.

• Journal of Marine Bioscience and Biotechnology
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• v.12 no.1
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• pp.40-49
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• 2020

This article emphasized the physiological characteristics of the selected marine microalgal strains obtained from the culture collection of the National Marine Biodiversity Institute of Korea (MABIK). Therefore, in this study, 13 different marine microalgal strains belonging to the phylum Chlorophyta were analyzed for the composition of fatty acids, elements, photosynthetic pigments, and monosaccharides, as well as the lipid and protein contents. The results presented that the primary fatty acids were palmitic (C_16:0), palmitoleic (C_16:1 n-7), stearic (C_18:0), oleic (C_18:1 n-9), linoleic (C_18:2 n-6), and α-linolenic (ALA, C_18:3 n-3) acid in the evaluated microalgae. The lipid contents of heterotrophically grown strains ranged from 15.1% to 20.4%. The calorific values of the strains were between 17.4 MJ kg^-1 and 21.3 MJ kg^-1. The major monosaccharides were galactose, glucose, and mannose, while the primary photosynthetic pigments were chlorophyll-a (Chla), chlorophyll-b (Chlb), and lutein, respectively. Based on the results, the microalgal strains showed high potentials in the use of microalgae-based technologies to produce biochemicals, food, and renewable fuels as they are rich in sustainable sources of high-value bio-compounds, such as antioxidants, carbohydrates, and fatty acids.

• Journal of fish pathology
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• v.34 no.1
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• pp.47-53
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• 2021

Scuticociliates are one of the serious parasitic threats faced by the marine aquaculturists worldwide. To date, Uronema nigricans, Philasterides dicentrarchi, Miamiensis avidus, Uronema marinum, and Pseudocohnilembus persalinus have been reported as the important culprit species causing scuticociliatosis in fish. The present paper reports the finding of an additional scuticociliate isolate from the gill of diseased olive flounder Paralichthys olivaceus in Korea. Based on the morphological characteristics, a scuticociliate in this study was identified as Paranophrys marina. Phylogenetic analysis placed P. marina as a sister lineage to three species of Pseudocohnilembus and Mesanophrys carcini within the order Philasterida.

• Journal of Veterinary Science
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• v.21 no.6
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• pp.86.1-86.8
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• 2020

Background: Dicyemids are parasites found in the renal sac of cephalopods. The first species of dicyemid was found from kidneys of the Korean common octopus Callistoctopus minor. Objectives: This study aimed to identify the dicyemid and investigate the effect on renal sac of host. Methods: In this study, we compared the morphological characteristics of isolate to dicyemids (Dicyema sphyrocephalum, Dicyema clavatum, and Dicyema dolichocephalum) reported from C. minor in Japan. We compared the 18S ribosomal RNA (rDNA) and cytochrome c oxidase subunit I (COI) sequences of isolate to the sequences of D. shyrocephalum and D. clavatum. The infected octopuses renal tissues were histologically compared with the tissues of uninfected individuals. Results: The morphological characteristic of this isolated species corresponds to D. sphyrocephalum. The sequences similarities of 18S rDNA and COI gene of isolate are 99.7% and 98.1% with D. sphyrocephalum. We observed morphological changes in the epithelia folds of kidney at the dicyemids attached areas. Conclusions: The present study identified the isolate as D. sphyrocephalum and this is the first report of dicyemid species from Republic of Korea. Further studies on the effects of dicyemids on growth and health status of cephalopods will be needed.

• Journal of Marine Life Science
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• v.7 no.2
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• pp.121-128
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• 2022

L-asparaginase (ASNase) is a therapeutic enzyme used to treat acute lymphoblastic leukemia. Currently, the most widely used ASNases are originated from bacteria. However, owing to the adverse effects of bacterial ASNases, new resources for ASNase production should be explored. Fungal enzymes are considered efficient and compatible resources of natural products for diverse applications. In particular, fungal species belonging to the genus Trichoderma are well-known producers of several commercial enzymes including cellulase, chitinase, and xylanase. However, enzyme production by marine-derived Trichoderma spp. remains to be elucidated. While screening for extracellular ASNase-producing fungi from marine environments, we found four strains showing extracellular ASNase activity. Based on the morphological and phylogenetic analyses using sequences of translation elongation factor 1-alpha (tef1α), the Trichoderma isolates were identified as T. afroharzianum, T. asperellem, T. citrinoviride, and Trichoderma sp. 1. All four strains showed different ASNase activities depending on the carbon sources. T. asperellem MABIK FU00000795 showed the highest ASNase value with lactose as a carbon source. Based on our findings, we propose that marine-derived Trichoderma spp. are potential candidates for novel ASNase production.