• Korean Journal of Environmental Biology
• /
• v.21 no.2
• /
• pp.164-169
• /
• 2003

Organotins are widely used organometals in various agricultural and industrial purposes. After introduction of these chemicals to the aquatic environment, they are degraded by abiotic and biotic precesses. The triorganotin compounds are sequentially degraded to di-organotin, mono-organotin and then finally inorganic tin. Although the effects of trialkyltin an marine organisms have been intensively studied, little has been known on plankton as a producer of ecosystem. In this paper, the toxicities of dibutyltin (DBT), monobutyltin (MBT), diphenyltin (DPT), monophenyltin (MPT), trimethyltin (TMT) and dimethyltin (DMT) to rotifer Brachionus plicatilis were measured, and their potencies were compared based on 96 hr-$LC_{50}$ value. The results showed that DPT (13.8 ppb) was the highest toxic, which was followed by TMT (42.9), DBT (80.6), MPT (262.2), MBT and DMT (>1,000) in order. Thus, in tri- and diorganotins, the toxicity was observed phenyltins > butyltins > methyltins, and in mono-organotins phenyltins was more toxic than butyltins. Considering the order of 96 hr--$LC_{50}$ with octanol-water eoefficients ($K_{ow}$) in organotins together, it was considered that the toxicity of organotins seems to be related to the lipophilicity of the compounds.

• Animal Systematics, Evolution and Diversity
• /
• v.28 no.4
• /
• pp.279-290
• /
• 2012

Plecoglossus altivelis (ayu) is an amphidromous fish widely distributed in Northeastern Asia from the East China Sea to the northern Japanese coastal waters, encompassing the Korean Peninsula within its range. The shore lines of northeastern region in Asia have severely fluctuated following glaciations in the Quaternary. In the present study, we investigate the population genetic structure and historical demographic change of P. altivelis at a population level in East Asia. Analysis of molecular variance (AMOVA) based on 244 mitochondrial control region DNA sequences clearly showed that as the sampling scope extended to a larger geographic area, genetic differentiation began to become significant, particularly among Northeastern populations. A series of hierarchical AMOVA could detect the genetic relationship of three closely located islands between Korea and Japan that might have been tightly connected by the regional Tsushima current. Neutrality and mismatch distribution analyses revealed a strong signature of a recent population expansion of P. altivelis in East Asia, estimated at 126 to 391 thousand years ago during the late Pleistocene. Therefore it suggests that the present population of P. altivelis traces back to its approximate demographic change long before the last glacial maximum. This contrasts our a priori expectation that the most recent glacial event might have the most crucial effect on the present day demography of marine organisms through bottleneck and subsequent increase of effective population size in this region.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.40 no.1
• /
• pp.60-64
• /
• 2004

The reason of the loss for the plastic sea-eel pots were estimated as crew's mistake, strong current, bad weather, rough seabed, artificial reef and other boats' fishing. Especially, pot loss happened on the fishing could make some additional catch, loss of the catches and ghost fishing because there are baits and alive fish in the lost pot. Quantity of the lost pots was estimated as 2~4 times of the ordinary usage. On the result of investigation to analyze the possibility of sustainable ghost fishing for the lost pot to feed the fishes at anytime because there were blenny, silver whiting, bar-tailed flathead and shrimp including sea-eel in the lost pot. In the bioeconomic point, ghost fishing is competitive with the general fishing. Accordingly, usage of biodegradable plastic material for the plastic sea-eel pot will be better to reduce ghost fishing

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.50 no.6
• /
• pp.669-674
• /
• 2017

Paralytic shellfish toxins (PSTs) are produced by marine dinoflagellate phytoplankton Alexandrium spp. and Gymnodinium spp. These toxins accumulate in filter feeding organisms such as bivalves and the ingestion of contaminated shellfish can cause illness in humans. The mouse bioassay (MBA) has been the preferred PST testing method worldwide for more than 50 years. However, this assay has several disadvantages, such as detection limits, non-toxic-profiles, and the ethical issues of using animals. The aim of this study was to establish an alternative to the MBA method for testing for PSTs. We optimized the analysis conditions of a post-column oxidation-high performance liquid chromatography (PCOX-HPLC) method and the Scotia Rapid Test Kit, and then compared the accuracy of these methods to the MBA method. The results demonstrated a strong correlation between the PCOX-HPLC method and the MBA, although the PCOX-HPLC method required expensive equipment and standard material, and was time consuming. The Scotia Rapid Test Kit promises to be a useful tool, as it provided rapid and qualitative results, although the method sometimes gave a false positive result that could not be explained by toxin profiles.

• Analytical Science and Technology
• /
• v.23 no.5
• /
• pp.477-484
• /
• 2010

Personal care products are a diverse group of synthetic organic chemicals such as antimicrobial compounds, UV filters and organo-phosphate flame retardants and derived from individual usages of soaps, toothpaste and cosmetics. It has been detected in municipal sewage effluent and various environmental samples such as surface water, marine, soil, sediment and aquatic biota in many countries. The occurrence of personal care products in environmental samples could negatively impact the health of the ecosystem and humans, due to persistent, long-term chronic exposure of aquatic organisms. In this study, fifteen personal care products in aquatic environmental samples were determined by gas chromatography-mass spectrometry (GC-MS) with liquidliquid extraction (LLE). Method detection limits were in the range of $0.004\sim0.273\;{\mu}g/L$. Two compounds (TCEP, TCPP) were detected in surface waters and seven compounds (triclosan, 4-MBC, EHMC, BP-3, TCEP, TPP, TBEP) were detected in sewage treatment plants (STP) influents or effluents.

• Korean Journal of Environmental Biology
• /
• v.32 no.4
• /
• pp.306-310
• /
• 2014

The brown seaweed Sargassum fusiforme is an edible and highly valued in Korea. During the summer season, phytal organisms graze heavily on young algal blades and holdfastsof the species and substantially reduce harvestable biomass. Here, in this study, we investigated the effects of pH (range: 2~13) and salinity (range: 0~44 psu) on the removal of two major phytal animals, Caprella scaura and Gammaropsis utinomi, associated with S. fusiforme. We also examined the optimum quantum yield (Fv/Fm) of algae in the same experimental conditions to quantify the tolerance of algae to acid and salinity treatments. It was observed that the phytal animals showed more than 80% mortality at pH lower that pH 4 and the extreams of salinity (0~10 psu and 44 psu) after a 5 min of immersion. However, the quantum yield of S. fusiforme was not significantly different from controls within the pH 3~11 range, and the 0~44 psu salinity range. Precisely, if the pH and salinity conditions outside these ranges were used in comercial Sargassum culture, the removal of the animal species would be higher, but with reduced quantum yield of algae. Taken together, our study results indicated that the pH and salinity treatments could allow multiple harvests from the same holdfast of S. fusiforme.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.38 no.6
• /
• pp.347-352
• /
• 2005

These experiments investigated the conditioning pattern and the nitrification efficiency of a fluidized sand biofilter (FSB) for seawater application. The FSB fed artificial nutrient was fully conditioned within 22 weeks. The maximum nitrification efficiency of the FSB was achieved at a superficial water velocity (SWV) of 1.0 cm/sec. After fixing the superficial water velocity at 1.0 cm/sec, the nitrification rates of the FSB were assessed at 3 total ammonia nitrogen (TAN) loading rates (250, 500, 1,000 g TAN/$m^3$/day) and 3 water temperatures (12, 16, $20^{\circ}C$). The TAN concentration in the simulated culture tank ranged from 2.87 to 9.72 mg/L at TAN loading rate of 1,000 g TAN/$m^3$/day, while that ranged from 0.45 to 1.26 mg/L at TAN loading rate of 500 g TAN/$m^3$/day. The ranges of TAN concentration in the former were too high for aquatic organisms and those in the latter were acceptable. Therefore, the safe TAN loading rate for the FSB in seawater conditions was decided as 500 g TA/$m^3$/day. From these results, daily TAN removal rates (g TAN/$m^3$/day) of FSB under conditions of inlet TAN concentration (C, mg/L) and water temperature (T, $^{\circ}C$) were calculated by the following non-linear multi-regression equation: TAN removal rate: f(z)=-1,311.295+655.714LnT+225.775LnC ($r^2=0.962$).

• Archives of Pharmacal Research
• /
• v.27 no.12
• /
• pp.1226-1232
• /
• 2004

Extracts from seventeen seaweeds were determined for tyrosinase inhibitory activity using mushroom tyrosinase with L-tyrosine as a substrate. Only one of them, Ecklonia stolonifera OKAMURA (Laminariaceae) belonging to brown algae, showed high tyrosinase inhibitory activity. Bioassay-guided fractionation of the active ethyl acetate (EtOAc) soluble fraction from the methanolic extract of E. stolonifera, led us to the isolation of phloroglucinol derivatives [phloroglucinol (1), eckstolonol (2), eckol (3), phlorofucofuroeckol A (4), and dieckol (5)]. Compounds 1~5 were found to inhibit the oxidation of L-tyrosine catalyzed by mushroom tyrosinase with $IC_{50}$ values of 92.8, 126, 33.2, 177, and 2.16 ${\mu}g$ /mL, respectively. It was compared with those of kojic acid and arbutin, well-known tyrosinase inhibitors, with $IC_{50}$ values of 6.32 and 112 ${\mu}g$ / mL, respectively. The inhibitory kinetics analyzed from Lineweaver-Burk plots, showed compounds 1 and 2 to be competitive inhibitors with $K_i$ of $2.3{\times}10^{-4}\;and\;3.1{times}10^{-4}$ M, and compounds 3~5 to be noncompetitive inhibitors with $K_i$ of $1.9{\times}10^{-5},\;1.4{\times}10^{-3}\;and\;1.5{\times}10^{-5}$ M, respectively. This work showed that phloroglucinol derivatives, natural compounds found in brown algae, could be involved in the control of pigmentation in plants and other organisms through inhibition of tyrosinase activity using L-tyrosine as a substrate.

• Journal of Environmental Science International
• /
• v.16 no.7
• /
• pp.799-804
• /
• 2007

Oil spill caused severe effects on the marine fauna and flora due to direct contact of organisms with the oil and even in regions not directly affected by the spill. This study was conducted to understand the effects of the oil spill accidents and the use of dispersant on the red tide of Cochlodinium polykrikoides. Crude oil produced in Kuwait, bunker-C, kerosene and diesel oil, and a chemical dispersant produced in Korea, were added with a series of 10 ppb to 100 ppm in the f/2-Si medium at $20^{\circ}C$ under a photon flux from cool white fluorescent tubes of $100\;mol\;m^{-2}\;s^{-1}$ in a 14: 10 h L:D cycle for the culture of C. polykrikoides. In low concentrations of ${\leq}$ 1 ppm of examined oils no impact on the growth of C. polykrikoides was recorded, while in high concentration of ${\geq}$ 10 ppm, cell density was significantly decreased with the range of 10 to 80% in comparison with the control. The growth of C. polykrikoides after the addition of the dispersant and the mixtures combined with oils and a dispersant of ${\geq}$ 10 ppm appeared to decrease, whereas the growth of C. polykrikoides exposed to ${\leq}$ 100 ppb showed little serious impact. However, almost all the C. polykrikoides cells were died regardless of a dispersant and combined mixtures within a few days after the addition of high concentrations.

• Animal cells and systems
• /
• v.4 no.1
• /
• pp.1-7
• /
• 2000

The genus Dendronephthya, generally known as soft corals, is reported as an abundant and variable taxon. They mostly distribute in warmer waters of the Undo-Pacific Ocean region including Korea. In spite of their abundance and ecological importance as habitats of marine organisms, there are difficulties in the study of their identification and systematics because they have morphological variabilities and limited taxonomec characters. To resolve the problems, we attempted to elucidate the genetic relationships in the genus Dendronephthya by using random amplified polymorphic DNA (RAPD) analysis. This study was based on eight dendronephthian species and one Alcyoniidae species, Alcyonium gracillimum, as an outgroup. The results from all analysis suggest that they could be classified into four groups by the growth form and the anthocodial grades as follows: the first one,D. putteri and D. suensoni with the divaricate form and VI grade; the second one,D. sp.1 and D. sp.2 with the divaricate form and III or IV grade; the third one, D. gigantea and D. aurea being closer than D. spinifera with the glomerate form and III grade; the last one, D. castanea related to D. gigantea rather than D. putteri with the umbellate form and IV grade. Moreover, the divaricate form was separated from the group of the glomerate and umbellate form. At the intraspecies level, the types of the D. castanea, D. gigantea and D. spinifera were separated depending on the feature of spicules in the polyp head, and the coloration could not influence genetic variation. From this study, we can confirm that their morphological characters are compatible with the genetic variation, also RAPD analysis is a very useful method for resolving the systematic relationships of den-deonephthians.