• Animal Systematics, Evolution and Diversity
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• v.39 no.1
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• pp.10-15
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• 2023

Two pelagic thaliacean tunicates, Pyrosoma atlanticum and Cyclosalpa quadriluminis, with bioluminescent organ, were collected from Jejudo Island and Korea Strait. In this study, the Pyrosomatida, which is holoplanktonic colonial tunicate with ascidiozooids embedded in a common test, and to which P. atlanticum belongs, is reported for the first time in Korea. The Cyclosalpa in the Salpida has a bar-shaped alimentary canal beside the branchial bar in both oozooids and blastozooids. Cyclosalpa quadriluminis is added to make Cyclosalpa species in Korea from four to five (C. affinis, C. bakeri, C. polae, C. sewelli, and C. quadriluminis). As a result of this study, 27 species of thaliaceans have been reported from Korea.

• Animal Systematics, Evolution and Diversity
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• v.27 no.2
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• pp.197-200
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• 2011

Tunicates were collected from three harbors (Gampo, Bangeojin, Daebyeon) in Gyeongsangnam-do and one harbor (Seogwipo) in Jejudo Island during the period from August 2008 to January 2011 and were identified on the basis of their morphological characteristics. Among them, colonial tunicate Clavelina lepadiformis (Muller, 1776) belonging to the family Clavelinidae was found to be an invasive alien species introduced from the North Atlantic, and this is the first record of its occurrence in Korea.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2001.05a
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• pp.230-231
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• 2001

지금까지 많은 항균성 펩타이드가 포유류 (1), 양서류 (2), 곤충 (3) 및 식물 (4)로 부터 단리ㆍ정제되었고, 구조-활성간의 연구가 활발히 진행되고 있지만, 이러한 연구는 육상생물에 제한적으로 수행되어 겼으며 해양생물을 대상으로 한 연구는 극히 제한되어 있는 상태이다. 해양생물로부터 정제된 항균성 펩타이드로서는 Flounder skin 분비물에서 pleurocidin (5), Moses sole fish에서 pardaxins (6), Horseshoe crab에서 Tachyplesin I(7), Tunicates hemocytes에서 Clavanins (8), Mollusc에서 Mytilins (9) 등이 보고되고 있지만 불가사리를 이용한 항균성물질의 연구는 희박한 실정이다. (중략)

• Korean Journal of Fisheries and Aquatic Sciences
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• v.53 no.2
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• pp.174-180
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• 2020

The mouse bioassay has been used widely for the monitoring of paralytic shellfish toxins (PSTs) in many countries. However, this method shows low sensitivity and high limit of detection (LOD), as well as it cannot confirm toxic profiles. Recently, LC-MS/MS method was studied for the quantitative of PSTs, however, the method has any problems with unstable retention times by ionization suppression caused by high salt concentration in shellfish extracts. To establish an alternative method for PSTs analysis, we tried to original LC-MS/MS methods adding desalting operation using amorphous graphitized polymer carbon solid-phase extraction cartridges. The method validation was conducted to determine linearity, limit of detection, limit of quantification (LOQ), accuracy, and precision in quantifying PSTs. The correlation coefficients for all tested PSTs maintained over 0.999. The LODs and LOQs for all PSTs were about 0.19-1.05 ㎍/kg and 0.58-3.18 ㎍/kg, respectively. The accuracies for PSTs were 95.4-107.7% for saxitoxin group, 97.1-100.9% for gonyautoxin group, 99.0-100.8% for N-sulfocarbamoyl toxin group, and 96.8-104.6% for decarbamoyl toxin group. These results indicate that the modified LC-MS/MS method was appropriate for analyzing the PSTs in shellfish and tunicates.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.54 no.4
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• pp.404-410
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• 2021

Although, mouse bioassay for the monitoring of azaspiracids (AZAs) toxins in shellfish has been used previously, the reported method has low sensitivity and it is time-consuming. Recently, there is an interest in the quantitative analysis of AZAs using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The purpose of this study is to verify the simultaneous analysis of AZAs in shellfish and tunicate in Korea using LC-MS/MS. To validate the method, linearity, limit of detection (LOD), limit of quantification (LOQ), precision, accuracy, and repeatability were determined. All standard compounds were analyzed within 7 min. The correlation coefficients (R²) of the standard solution was higher than 0.9995 (within the range of 0.8-10.0 ㎍/L). The LODs and LOQs of AZAs in shellfish were 0.08-0.16 ㎍/kg and 0.23-0.50 ㎍/kg, respectively. The accuracy and precision of the method for determining AZAs in shellfish were 87.1-93.0% and 1.23-4.91%, respectively. Consequently, the verified LC-MS/MS method is suitable to analyze AZAs in shellfish and tunicates in Korea.

• Natural Product Sciences
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• v.13 no.3
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• pp.229-233
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• 2007

Chemical investigation of the crude extract of the Egyptian marine tunicate Eudistoma laysani led to the isolation of a new nucleoside; 3-deazainosine and four known ones; inosine, 2'-deoxyuridine, adenosine and 2'-deoxyadenosine. Structural elucidation of the isolated compounds was based on intensive studies of their spectral data including 1D ($^{1}H$ and $^{13}C$) and 2D ($^{1}H-^{1}H$ COSY, HMQC, HMBC) NMR together with mass spectra. The antioxidant effects of the isolated compounds were determined using DPPH, where they exhibited significant activities.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.41 no.4
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• pp.237-242
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• 2008

The tunic of Styela clava(SCT) consists of a proteoglycan network. Regenerated cellulose films were prepared by solution casting and coagulation of SCT in N-methylmorpholine-N-oxide(NMMO)/$H_2O$(87/13 wt%). The crystalline structure of powdered SCT was primarily that of cellulose I. The crystalline structure of SCT films exhibited a cellulose II structure, similar to that of viscose rayon. Physical characterization of SCT films and fibers revealed an intrinsic viscosity($\eta$) of 6.35 dL/g, average molecular weight($M_w$) of 423,000 g/M, and fiber density of 1.50 $g/cm^3$ with a moisture regain and water absorption of 10.20% and 365%, respectively. The results were similar to those of cellulose films regenerated from wood pulp. Films prepared with 6 wt% SCT exhibited strong tensile strength, high water absorption, and a greater degree of elongation. Scanning electron micrographs(SEM) of film cross-sections showed a layered, sponge-like structure.

• Proceedings of the Korean Society of Sericultural Science Conference
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• 2003.10a
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• pp.87-90
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• 2003

Cytokines represent an essential part of the innate immune response in mammals. Recently, several studies have reported presence of cytokine-like activities and molecules in the invertebrates such as echinoderms, tunicates, molluscs and insects (Beck and Habicht, 1986; Beck et al.; 1959; Ottaviani et al.; 1993; Franchini, 1996). The cytokines found in those organisms include IL-1, IL-2, IL-6, and tumor necrosis factor (TNF). (omitted)

• Journal of Marine Bioscience and Biotechnology
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• v.2 no.4
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• pp.209-223
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• 2007

Nature is one of the most important sources of pharmacologically active compounds in the search for drugs against life threatening diseases. Even though plants and terrestrial microorganisms have played as an important source for the new drug candidates from nature, marine organisms such as tunicates, sponges, soft corals, sea horses, sea snakes, marine mollusks, seaweeds, nudibranches, sea slugs and marine microorganisms are increasingly attracting attention in recent years. Marine organisms also have the potential to develop into future drugs against important diseases, such as cancer, a range of bacterial and viral diseases, malaria, and inflammations. Even though the mechanism of action in the molecular level of most metabolites is still unclear, the mechanisms by which they interfere with the pathogenesis of a wide range of diseases have been reported. The knowledge of this is one of the key factors necessary to develop bioactive compounds into medicines. This is due to their structurally unique and pharmacologically active compounds. The potential pharmaceutical, medicinal and research applications of some of these compounds are discussed in hundreds of scientific papers, and are reviewed here.

• The Korean Journal of Malacology
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• v.28 no.3
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• pp.277-291
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• 2012

Aquaculture is challenged by a number of constraints with future efforts towards sustainable production. Global climate change has a potential damage to the sustainability by changing environmental surroundings unfavorably. The damaging parameters identified are water temperature, sea level, surface physical energy, precipitation, solar radiation, ocean acidification, and so on. Of them, temperature, mostly temperature elevation, occupies significant concern among marine ecologists and aquaculturists. Ocean acidification particularly draws shellfish aquaculturists' attention as it alters the marine chemistry, shifting the equilibrium towards more dissolved CO2 and hydrogen ions ($H^+$) and thus influencing signaling pathways on shell formation, immune system, and other biological processes. Temperature elevation by climate change is of double-sidedness: it can be an opportunistic parameter besides being a generally known damaging parameter in aquaculture. It can provide better environments for faster and longer growth for aquaculture species. It is also somehow advantageous for alleviation of aquaculture expansion pressure in a given location by opening a gate for new species and aquaculture zone expansion northward in the northern hemisphere, otherwise unavailable due to temperature limit. But in the science of climate change, the ways of influence on aquaculture are complex and ambiguous, and hence are still hard to identify and quantify. At the same time considerable parts of our knowledge on climate change effects on aquaculture are from the estimates from data of fisheries and agriculture. The consequences may be different from what they really are, particularly in the temperature region. In reality, bivalves and tunicates hung or caged in the longline system are often exposed to temperatures higher than those they encounter in nature, locally driving the farmed shellfish into an upper tolerable temperature extreme. We review recent climate change and following environment changes which can be factors or potential factors affecting shellfish aquaculture production in the temperate region.