• Korean Journal of Fisheries and Aquatic Sciences
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• v.34 no.6
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• pp.584-587
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• 2001

The effects of tributyltin (TBT), triphenyltin (TPhT) and Aroclor 1254 on germinal vesicle breakdown (GVBD) and ovulation of olive flounder (Paralichthys olivaceus) were investigated in in vitro bioassay. TBT, TPhT and Aroclor 1254 showed the inhibition effects on GVBD and ovulation in response to HCG. The oocyte response appeared to be more sensitive to TBT than Aroclor 1254. TBT was more effective in inhibition GVBD at concentrations of 0.1 and 1 ppm. However, no significant inhibition was obseued in concentrations tested ($0.0001\~1\;ppm$). Significant inhibition of ovulation in response to HCG occurred at TBT (0.01, 0.1, 1 ppm), TPhT (0.01, 0.1, 1 ppm) and Aroclor 1254 (0.01, 1 ppm, except 0,1 ppm), compared to HCG control, The lowest ovulation rate was measured at 1 ppm TBT, These data suggest that TBT (or TPhT) could possibly interfere the actions of progestogens to induce GVBD and ovulation in in vitro bioassay system.

• Natural Product Sciences
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• v.11 no.1
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• pp.50-53
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• 2005

Bioassay-directed fractionation of the lipophilic extract of a marine sponge Sarcotragus sp. led to the isolation of a known trisoxazole containing macrolide, mycalolide B (1). Its structure was identified by NMR and MS analyses. This is the first report on the isolation of macrolide from a sponge of the genus Sarcotragus (Order: Dictyoceratida).

• Natural Product Sciences
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• v.11 no.3
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• pp.136-138
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• 2005

Bioassay-guided fractionation of an organic extract of the broth from the marine-derived fungus of the genus Aspergillus led to the isolation of the polyketides, (+)-epoxydon (1), (+)-epoxydon monoacetate (2), gentisyl alcohol (3), 3-chlorogentisyl alcohol (4), and methylhydroquinone (5). Compounds 1-5 showed a potent antibacterial activity against the methicillin-resistant and multidrug-resistant Staphylococcus aureus (MRSA and MDRSA) with MIC (minimum inhibitory concentration) values of 12.5, 12.5, 12.5, 50.0, and $6.2\;{\mu}g/mL$, respectively. Compounds 1-4 also exhibited a significant radical scavenging activity against 1,1-diphenyl-2-picrylhydrazyl (DPPH) with $IC_{50}$ values of 6.0, 15.0, 7.0, and $1.0\;{\mu}M$, respectively.

• Journal of Marine Bioscience and Biotechnology
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• v.2 no.2
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• pp.77-80
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• 2007

Macroalgal tissues can be used as indicating materials for environmental assessment using several algal biotechnology techniques. As bioassay test organisms, macroalgal tissues are required as an axenic state for suitable biological indicators. Callus formation and blade regeneration under suitable culture conditions are also useful for the tests. Quantitative method using tetrazolium chloride or $alamarBlue^{TM}$ is devised on a rapid assessment of the seaweed viability. The use of RT-PCR especially differential display technique should provide the means for the detection and isolation of the responding genes induced by the environmental stress. Seaweed thriving in more environmental changes might contain more diverse biologically active substances.

• Biotechnology and Bioprocess Engineering:BBE
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• v.11 no.1
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• pp.13-18
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• 2006

The antioxidant activity of the extract of Erigeron annuus was assessed by means of two different in vitro tests: bleaching of the stable 1,1-diphenyl-2-picrylhydrazyl radical (DPPH test) and the scavenging of authentic peroxynitrite in company with peroxynitrite generation from 3-morpholinosydnonimine (SIN-1). In both tests, the 85% aq. MeOH and n-BuOH soluble fractions of the crude extract showed a significant scavenging effect on peroxynitrite and DPPH radical in comparison to L-ascorbic acid. And bioassay-guided fractionation of the n-BuOH soluble fraction led to the isolation of three compounds: Apigenin (1), quercetin-3-O-glucoside (2), and caffeic acid (3). The structures of the isolated compounds were elucidated on the basis of their spectroscopic data and their antioxidant activities were measured by determining their capacity to scavenge peroxynitrite and the DPPH radical.

• Bulletin of the Korean Chemical Society
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• v.28 no.6
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• pp.990-994
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• 2007

Bioassay-guided fractionation of the MeOH extract from the sponge Discodermia calyx collected off the coast of Jeju Island, South Korea, led to the isolation of a polyketide, icadamide C (1), along with previously reported theopederin K (3). Structure elucidation was performed by a combination of high resolution mass and 2D-NMR (principally COSY, HMBC, HSQC, and NOESY) spectroscopy. Stereochemistry of compound 1 was determined as 2R*, 3R*, 6R*, 10S*, 11S*, 12R*, 13S*, 15R* and 2'S by NMR data and Marfey analysis. Isolated metabolites displayed potent cytotoxic activity against a small panel of five human solid tumor cell lines with ED50 values of less than 0.1 μg/mL.

• Journal of Life Science
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• v.10 no.2
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• pp.196-201
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• 2000

The production of tetrodotoxin (TTX) using Vibrio sp. YE-101, a novel marine microorganism isolated from the intestine of pufferfish, was investigated. Culture condition was optimized for the enhanced production of TTX using response surface methodology. The experimental sets of environmental conditions including pH, temperature and NaCl concentration were designed using central composite experimental design. The optimal conditions of pH, temperature and NaCl concentration were determined to be 8.1, 29.2℃, and 2.6% (w/v) respectively. The relative growth extent could be enhanced up to 80%, and final mouse unit (MU) value of TTX was also enhanced up to 87% by response surface optimization.

• Journal of Environmental Science International
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• v.14 no.12
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• pp.1129-1139
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• 2005

A series of experiments was conducted to identify the potential of five phytoplankton species as standard test species for marine ecotoxicological tests. The candidate phytoplankton species are Skeletonema costatum, Heterosigma akashiwo, Prorocentrum micans, Isochrysis galbana, and Tetraselmis suecica. Salinity tolerance and sensitivity on potassium dichromate as a reference material were identified. Toxicity of eleven ocean dumped sewage sludges and four red tide expellent extracts were estimated by the inhibition of population growth rates (PGR) of marine diatom S. costatum, While most species revealed relatively weak tolerance on salinity, T. suecica demonstrated the highest salinity tolerance ranged from $5\~35$ psu and the others $15\~35$ psu. H. akashiwo revealed the highest sensitivity as 72h $IC_{50}$=0.76mg/L and T. suecica the lowest as 72h $IC_{50}$=8.89mg/L on potassium dichromate. Sludge extracts from industrial waste, domestic sewage and livestock farm waste sludge showed high toxicity as 72h $IC_{50}$<$2\%$ and lowest toxicity from filtration bed sludge as 72h $IC_{50}$=$30.50\%$ NOEC (No Observed Effective Concentration) of sludge extract ranged from <$0.4\%$ to $1.6\%$ and this indicated high phytotoxicity of ocean dumped sewage sludge. The test sensitivity of phytoplankton PGR inhibition was much higher than those of marine rotifer Brachionus plicatilis mortality test and bioluminescent inhibition test by marine bacteria Vibrio fischeri, and comparable with the sea urchin (Strongylocentrotus intermedius) fertilization test. As a result the phytotoxicity test using phytoplankton PGR inhibition ($IC_{50}$) must be a useful tool for marine phyto-toxicological evaluation of ocean dumped materials.

• Journal of fish pathology
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• v.22 no.1
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• pp.67-73
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• 2009

It was examined whether the common belief that "cultured puffer fishes do not contain tetrodotoxin (TTX)", the major lethal substance that accidently causes death in consumers of those fishes, is true in river puffer fish Takifugu obscurus. In mouse bioassay, lethal levels of toxins were detected in the ranks: gonad>liver>intestine>muscle>skin in wild puffer fish. In contrast, no mortality occurred in the mouse bioassay on cultured fish. However, there were sleepiness, sluggish behavior, and hind limb paralysis with the tissue extracts of cultured fish suggesting the presence of TTX or other similarly acting toxins. An attempt to confirm the presence of TTX in cultured fish with high performance liquid chromatography (HPLC) was not very successful. The results suggest possible existence of TTX toxins or similarly acting toxins.

• Ocean and Polar Research
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• v.29 no.4
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• pp.327-337
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• 2007

Plankton communities have close relationships with environmental changes in water columns. Thus, the use of plankton as a biological tool for assessing the marine ecosystem health may be effective. Major issue regarding coastal pollution has been usually recognized as phytoplankton blooms or red tides caused by the eutrophication, an increase in concentration of inorganic nutrients such as nitrogen and phosphorus. However, in order to understand the effects of the overall pollution on marine ecosystem, the organic pollutants as well as the inorganic nutrients should be also considered. For understanding the effects of the organic pollution, among the planktonic organisms, heterotrophic bacteria, heterotrophic flagellates and ciliates should be investigated. Generally, there are three approaches for assessing the marine ecosystem health using the plankton taxa or plankton communities. The first one is a community-based approach such as diversity index and chlorophyll a concentration which are common in analysis of the plankton communities. The second is an indiviual-based approach which is to monitor the pollution indicative species. This approach needs one's ability to identify the plankton to species level. The last approach is a bioassay of toxicity, which can be applied to the plankton. A pilot study in Masan Bay was conducted to assess the effects of the inorganic and organic pollution. In this article, a new approach using plankton communities was tentatively presented as a biological tool for assessing the ecosystem health of Masan Bay.