• Journal of Marine Bioscience and Biotechnology
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• v.9 no.2
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• pp.49-57
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• 2017

We isolated marine bacterium, isolate DG-2 which produces the antibiotics against MRSA (methicillin-resistant Staphylococcus aureus). This isolate DG-2 was examined by its morphological, biochemical properties, and 16S rRNA sequencing analysis. And then, isolate DG-2 was identified to the genus Streptomyces. Therefore, this isolate was designated as Streptomyces sp. DG-2. Streptomyces sp. DG-2 grew relatively well at $25^{\circ}C$, pH 7.0, and NaCl 1.0%. For the pre-purification of the bioactive compounds, DG-2 was fermented in 30 L PPES-II medium, and the culture filtrates of DG-2 was extracted by ethyl acetate. The ethyl acetate extract of DG-2 showed the significant anti-MRSA and antibacterial activities.

• Journal of Marine Bioscience and Biotechnology
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• v.1 no.4
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• pp.225-231
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• 2006

The secondary metabolites from Taiwanese marine soft corals and sponges have attracted much attention because they possess considerable potential biological activities. To explore the origin of bioactivity, many cytotoxic natural products were isolated and characterized in the past few years. For examples, The lipophilic extracts from marine sponges Petrosia elastica and Ircinia formosana were found active against several human tumor cells. The investigation of the gorgonian Junceela has also resulted in the discovery of a series of new juncenolides. Bioassay-directed fractionation of Clavularia viridis yielded seven new prostanoids. These compounds have been tested and evaluated as potential antitumor agents. The soft corals of the genus Cespitularia produced novel secondary metabolites with diverse chemical structures and interesting biological activities. Four new norditerpenoids, designated cespitulactones and cespihypotins were isolated from Cespitularia hypotentaculata. Cespitulactones are novel structures having a bond cleavage between C-10 and C-11. In addition, three novel diterpenes were isolated from C. taeniata and designated cespitulactams A, B and C having a phenylethyl amino side chain.

• Journal of Marine Bioscience and Biotechnology
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• v.2 no.2
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• pp.73-76
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• 2007

A large number of natural products were worldwidely discovered from maine organisms. There are many secondary metabolites produced by maine organisms which showed very strong bio-activities and distinct bio-active mechanisms. In korea, about 350 secondary metabolites including more than 280 novel compounds have been isolated and structually defined. Many researches for developing products such as cosmetics, functional food materials, anti-fouling substances are being performed using distinct activities of marine organisms. Although the research on marine natural products has been remained at its initial or developing stage of drug development, significant progress has been made for isolation, structure determination and bioassay of secondary metabolites.

• 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.

• Journal of Marine Bioscience and Biotechnology
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• v.1 no.3
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• pp.206-212
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• 2006

Supercritical carbon dioxide ($SCO_2$) extraction was investigated as a method for protein-sourcing material from squid viscera. To find the optimum conditions, the extraction of squid viscera using $SCO_2$ was performed under the conditions of temperature range from 35 to $45^{\circ}C$ and constant pressure 25 MPa using Hewlett-Packard 7680T. Also from result of SDS-PAGE, the protein denaturation was minimized when using $SCO_2$ extraction. And the major amino acids in the squid viscera were glutamic acid, aspartic acid, lysine, leucine, arginine, alanine, glycine, isoleucine, and valine. The main fatty acids from squid viscera were myristic acid, palmitic acid, stearic acid, heneicosanoic acid, palmitoleic acid, elaidic acid, oleic acid, eicosenoic acid, EPA (eicosapentaenoic acid), and DHA (docosahexaenoic acid).

• Journal of Marine Bioscience and Biotechnology
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• v.2 no.4
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• pp.257-262
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• 2007

Squid viscera oil was investigated by pretreatment method for enhancing the commercial value. Transeterification was performed to reduce rancidity of the oil, off-flavor was removed by using activated carbon adsorption. Analysis using ATD (Automatic Thermal Desorber) and GC/MG shows the efficacy of off-flavor removement. The rates of Transesterification employing inorganic catalyst and biocatalyst were tested, respectively. With stepwise addition of ethanol, the most efficiency of the reaction was achieved by inorganic catalyst. The efficiency of the reaction was estimated by acid value corresponding to rancidity of reaction product.

• Journal of Marine Bioscience and Biotechnology
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• v.2 no.4
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• pp.230-233
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• 2007

Protein tyrosine phosphatase 1B (PTP1B) acts as a negative regulator of insulin signaling, and selective inhibition of PTP1B has served as a potential drug target for the treatment of type 2 diabetes. As part of our searching for PTP1B inhibitors from natural products, the extracts of marine microorganisms were screened for the inhibitory effects on the activity of protein tyrosine phosphatase 1B (PTP1B). Among the tested 304 extracts, 29 extracts exhibited inhibition rate ranging 40.1 - 83.6 % against PTP1B at the concentration level of $30{\mu}g/mL$.

• Journal of Marine Bioscience and Biotechnology
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• v.2 no.4
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• pp.245-249
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• 2007

High quality of purified alginate and fucoidan is required for the medical uses to prevent the unexpected side effects from the contaminated endotoxin present in the materials. We attempted to establish an efficient and fast mass scale production method for the highly purified poly-G alginate from the sea weeds. In addition, lab scale method was established to obtain the fraction of higher purity from the commercially available fucoidan source (about 85% purity).

• Journal of Marine Bioscience and Biotechnology
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• v.6 no.2
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• pp.68-75
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• 2014

This study investigated the potential use of various organic carbon sources (glucose, glycerol and acetate) and different concentrations of $CO_2$ for culturing marine microalga Dunaliella tertiolecta. Cell growth and lipid production were monitored under heterotrophic, mixotrophic and photoautotrophic modes of cultivation. D. tertiolecta showed the ability to grow under mixotrophic (acetate and glucose), heterotrophic (glucose) and photoautotrophic condition under high $CO_2$ concentration (15%). With all the organic carbon sources (glucose, glycerol and acetate) tested in this study, 1~5% acetate enhanced cell growth rate and lipid content, while higher concentrations of acetate (10% and 15%) were inhibitory and resulted in cell death.

• Journal of Marine Bioscience and Biotechnology
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• v.6 no.2
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• pp.53-61
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• 2014

This study was investigated the antimicrobial activity of glutaraldehyde cross-linked glucosamine. Glutaraldehyde was used as a cross-linker which specifically combines an amine-group of molecules. To optimize the mixing ratio of glutaraldehyde and glucosamine, mixing ratio was set up 1:1, 2:1, 3:1 and 0.5:1 in molarity, respectively. The optimum mixing ratio of glucosamine and glutaraldehyde was found to be 3:1 using thin layer chromatography based on the production of complex. Glucosamine-glutaraldehyde cross-linked complex (Ggcc) revealed significant antimicrobial activity toward PWG than F1, both microbial strains were isolated from porcine semen as antibiotics resistance bacteria (ARB). These results clearly demonstrate that Ggcc has potential bactericidal activity toward ARB in porcine semen.