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제주도 연안에 서식하는 큰열매모자반의 형태적 특징과 계통 유연관계
고신자,김유경,이영돈 제주대학교 해양과학연구소 2021 해양과환경연구소 연구논문집 Vol.45 No.-
이 연구는 제주도 연안에 서식하는 큰열매모자반(Sargassum macrocarpum)의 종 동정을 위한 기초자료를 제공하기 위해 형태적 특성과 계통 유연관계를 조사하였다. 형태학적 분석 결과, 수집된 큰열매모자반은 원추상 부착기, 직립하는 줄기 그리고 주지의 치상돌기 등 형태적으로 기존에 보고된 연구결과와 유사한 양상을 보였다. 하지만 암생식기탁의 모양은 긴 주걱형과 도피침형에서 드물게 Y자형도 나타나 형태적 다양성이 관찰되었다. 부착기의 모양은 생육기간이나 부착기질에 적응하여 전형적인 원추상 에서 뭉툭한 다각형까지 여러 가지 형태적 변이를 보였다. 조천읍 조천리와 북촌리 연안에서 수집된 큰열매모자반의 mtDNA cox3 서열은 한경면 용당리에서 보고된 서열과 100% 일치하였는데, 이는 제주도 전 해역의 큰열매모자반이 유전적으로 동일한 기원 에서 유래된 것으로 판단되었다. 또한 큰열매모자반의 mtDNA cox3 서열이 Sargassum yamadae, S. siliquastrum의 서열들과 동일하여, 분류체계의 재조명이나, 교잡가능성과 생식적 격리에 대한 후속연구의 필요성을 시사하고 있다. 이번 연구결과는 해양생태계에서 해중림을 구성하는 주요 종 중 하나인 큰열매모자반의 형태적 특성과 계통 유연관계에 대한 정보를 통하여 모자반류의 종 동정 자료에 적용될 것이다. The purpose of this study was to investigate the morphological characteristics and phylogenetic relationship to provide information for the classification of Sargassum macrocarpum inhabiting Jeju Island, Korea. The morphological characteristics of S. macrocarpum such as conical holdfast, erect stem and denticle protuberances on both edges of the main branches were similar to those of previously reported for Sargassum morphology. However, morphological variation was observed as the female receptacle is long spatulate or oblanceolate and rarely Y-shaped. The shape of holdfast showed various morphological variations from a typical cone to a blunt polygon by adapting to the age or substrate shape. The nucleotide sequences of mtDNA cox3 gene obtained from Jocheon-ri and Bukchon-ri, Jocheon-up in this study were identical to those previously reported in Yongdang-ri, Hangyeong-myeon, suggesting that the S. macrocarpum populations over whole Jeju Island seacoast might be genetically derived from the same origin. In addition, the cox3 sequences of S. macrocarpum were identical to those of S. yamadae and S. siliquastrum, suggesting that it is necessary to review their taxonomic position and to carry out future studies on inter-specific hybridization and reproductive isolation among related species. The results of the present study will be applied to Sargassum species classification through the morphological characteristics and phylogenetic relationship of S. macrocarpum, as one of main species that form forests in marine ecosystems.
Hyun-Ki Hong,Chang Wan Kim,Jeong-Hwa Kim,Nobuhisa Kajino,Kwang-Sik Choi 제주대학교 해양과학연구소 2021 해양과환경연구소 연구논문집 Vol.45 No.-
In the rocky intertidal environment, the frequency and duration of heatwaves have increased over the last decade, possibly due to global climate change. Heatwaves often result in lethal or sub-lethal disturbances in benthic animals by changing their metabolic activities. In this study, we investigated the impacts of extreme heatwave stress on the hemocyte functions of Mytilisepta virgata and subsequent mortality to gain a better understanding of the potential causes and consequences of mass mortality events in this mussel during summer. We discriminated three types of hemocytes in the hemolymph, granulocytes, hyalinocytes, and blast-like cells, using flow cytometry and revealed that granulocytes were the major hemocyte involved in cellular defensive activities, such as phagocytosis and reactive oxygen species (ROS) production. For the experiment, mussels were exposed to a 40◦C air temperature for 12 h per day over 5 days under laboratory conditions as a simulated semi-diurnal tidal cycle. Mortality began to occur within 3 days after beginning the experiment, and all mussels had died by the end of the experiment. Flow cytometry indicated that the mussels exposed to high air temperatures produced significantly more ROS than did the control mussels within 2 days after the onset of the experiment, which may have caused oxidative stress. Such high levels of ROS in the hemolymph increased DNA damage in hemocytes after 3 days of exposure and decreased the phagocytosis of hemocytes 4 days after the experiment began. The observed mortality and decline in immune capacity suggested that an extreme heat event occurring in the rocky intertidal ecosystem during summer could exert sublethal to lethal impacts on macrobenthic animals.
남정만 제주대학교 해양과학연구소 1996 해양과환경연구소 연구논문집 Vol.20 No.0
The finite element method and the boundary element method are applied to analyze stress and deformation developed in the elastic ground which an urban tunnel with various section is excavated. The anaIytical results by both the finite element method and the boundary element method show relatively good agreement with Mindlin ’s solution. And this paper shows that the boundary element method is more favourable than the finite element method because the work to obtain same accuracy is simple and computing time is short. Also, to establish a reasonable design method for urban tunnel. minute investigation is carried out to variation of stress deformation around tunnel, subsidence and heave of ground etc.
Lei Wang,Thilina U. Jayawardena,Hye-Won Yang,Hyo Geun Lee,Min-Cheol Kang,K. K. Asanka Sanjeewa,Jae Young Oh,You-Jin Jeon 제주대학교 해양과학연구소 2020 해양과환경연구소 연구논문집 Vol.44 No.-
The previous study suggested that the sulfated polysaccharides from Hizikia fusiforme (HFPS) possess strong antioxidant activity. The purpose of this study is to isolate fucoidan from HFPS and to investigate its antioxidant activity. Afucoidan (HFPS-F4) with a molecular weight of 102.67 kDa was isolated from HFPS. HFPS-F4 contains 99.01% of fucoidan (71.79 ± 0.56% of carbohydrate and 27.22 ± 0.05% of sulfate content). The fucoidan increased the viability of H2O2-treated Vero cells by 5.41, 11.17, and 16.32% at the concentration of 12.5, 25, and 50 μg/mL, respectively. Further results demonstrated that this effect act diminishing apoptosis by scavenging intracellular reactive oxygen species (ROS) via increasing the expression of the endogenous antioxidant enzymes, which was induced by elevating total nuclear factor (erythroid-derived 2)-like 2 (Nrf2) levels. In addition, the in vivo test results displayed that the pretreatment of fucoidan improved the survival rates and decreased heart-beating rate, ROS, cell death, and lipid peroxidation in H2O2-stimulated zebrafish. Taken together, these results demonstrated that fucoidan isolated from HFPS has strong in vitro and in vivo antioxidant activities and it could be utilized in pharmaceutical, nutraceutical, and cosmeceutical industries.
Jeong-Hwa Kim,Hye-Mi Lee,Young-Ghan Cho,Jong-Seop Shin,Jae-Won You,Kwang-Sik Choi,Hyun-Ki Hong 제주대학교 해양과학연구소 2020 해양과환경연구소 연구논문집 Vol.44 No.-
Marine bivalves are often used as a sentinel species in coastal environmental monitoring since changes in the environmental quality are often well preserved in their cells and tissues. Anadara and Tegillarca species of Arcidae, the blood cockles, are considered to be good sentinel species in monitoring coastal pollution and ecosystem health because they are distributed widely in the subsurface of intertidal mudflats. Internal cellular defense of the blood cockles to physical and biological stresses is mediated by the circulating hemocytes, while their hemocyte types and functions are poorly studied. In this study, we first characterized morphology and immune-related activities of hemocytes of three common blood cockles Anadara broughtonii, A. kagoshimensis, and Tegillarca granosa using flow cytometry. Based on cell morphology and immunological functions, we described five types of hemocytes identically in the three blood cockles: erythrocytes type-I (erythrocytes-I), erythrocytes type-II (erythrocytes-II), granulocytes, hyalinocytes, and blast-like cells. Erythrocytes were round cells containing hemoglobin with numerous granules in the cytoplasm and these cells consist of two central populations. Erythrocytes-I were the most abundant cells accounting for 80–89% of the total circulating hemocytes and exhibited a certain level of lysosome and oxidative capacity. Erythrocytes-II were the largest cells and displayed high lysosome content and the most active oxidative capacity. Both erythrocytes-I and erythrocytes- II did not show phagocytosis capacity. Granulocytes were intermediated-sized hemocytes characterized by granules in the cytoplasm and long pseudopodia on the cell surface, and these cells were mainly engaged in the cellular defense exhibiting the largest lysosome content, the most active phagocytosis, and high oxidative capacity. Contrary to granulocytes, hyalinocytes were comparatively small and round cells and exhibited no granules in the cytoplasm. Hyalinocytes displayed a certain level of lysosome and phagocytosis and oxidative capacities. Blast-like cells characterized by the smallest size and small quantity of cytoplasm and exhibited an absence of phagocytosis and extremely low oxidative capacity, suggesting that this population is not directly involved in the cell-mediated immune activities. In conclusion, flow cytometry indicated that three blood cockles had five types of hemocytes, and the erythrocytes and granulocytes were mainly involved in the immunological activities.
Thatchaneshkanth Subramaniam,Hee‑Jung Lee,Hee‑Do Jeung,Hyun‑Sil Kang,Chul‑Won Kim,Hyung‑Seop Kim,Young‑Ghan Cho,Kwang‑Sik Choi 제주대학교 해양과학연구소 2021 해양과환경연구소 연구논문집 Vol.45 No.-
The Gray mussel Crenomytilus grayanus occurs in high density in the shallow rocky subtidal zone on the east coast of Korea, where the mussel dominates the shallow subtidal benthic community. In this study, we first examined the annual gametogenesis and temporal changes in the tissue composition, which provides crucial information to the management of the mussel on the east coast. Based on histological analysis, oogenesis and spermatogenesis commenced in September, as the small oogonia (16.67 ± 4.87 μm in diameter) and spermatogonia developed on the follicle walls, respectively. In March, the mature oocytes (46.55 ± 9.91 μm in diameter) and spermatozoa dominated the follicle. During May and June, most of the males and females spawned when the surface seawater temperature (SST) increased from 15.5 to 22.3 °C. The total carbohydrate level in the tissue increased dramatically from April to May, which coincided with the chlorophyll-a maximum occurring in April. Condition index, a ratio of tissue weight to shell weight, also increased from February to May and then declined in June, suggesting that most mussels released the gametes through spawning during these months. Our data suggest that C. grayanus is a spring spawner, and the onset of gametogenesis and subsequent spawning is closely linked to the seasonal changes in the water temperature and food availability in the water column.
D.S. Liyanage,W.K.M. Omeka,M.D. Neranjan Tharuka,Sumi Jung,Sukkyoung Lee,Jehee Lee 제주대학교 해양과학연구소 2020 해양과환경연구소 연구논문집 Vol.44 No.-
Syndecan-2, also known as CD362, is a transmembrane heparan sulfate proteoglycan which regulates cell growth, proliferation, cell adhesion, wound healing, and recruits immune cells. In the present study, we performed bioinformatics, spatial and temporal expression analyses of Hippocampus abdominalis syndecan-2 (HaSDC-2). Additionally, functional assays were conducted. HaSDC-2 has five major domains; an extracellular heparan sulfate attachment domain, a co-receptor binding domain, a transmembrane domain, two conserved domains (C1 domain, C2 domain), and a variable (V) domain. The ectodomain contained a signal peptide and GAG attachment sites. In-silico analysis revealed that HaSDC-2 contained a 798 bp long ORF and protein sequence of 265 amino acid residues. Further analysis of the amino acid sequence predicted a 28.9 kDa molecular weight and a 4.13 theoretical isoelectric point. The spatial expression of HaSDC-2 was ubiquitous in all tested tissues. HaSDC-2 expression in the liver was upregulated 24 h post-injection in response to all stimuli. Further, HaSDC-2 expression in blood cells was upregulated at 12 and 72 h post-injection in response to all the stimuli. HaSDC-2 + pcDNA™3.1(+) transfected cells exhibited significant survival in response to cell stressors such as H2O2 and HED. The ectodomain of recombinant HaSDC-2 treated cells showed significant cell proliferation in a concentration-dependent manner. The scratch wound healing assay showed significant Δ gap closures with increasing concentrations of HaSDC-2. Collectively, these results indicated that syndecan-2 was involved in regulating immune responses and cell stress conditions.