Publications by authors named "Ki Hwan Yu"

Color variation is a well-known feature of sea cucumbers (Apostichopus japonicus), which are classified into three groups based on their colors of red, green and black. It is also one of the most important traits related to how they taste, and it thereby affects their market price. Attempts were made to identify single-nucleotide polymorphisms (SNPs) and to analyze differences associated with SNP genotypes between green and red color variants using HSP70 as the target gene.

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Random mutagenesis was performed on beta-agarase, AgaB, from Zobellia galactanivorans to improve its catalytic activity and thermostability. The activities of three mutants E99K, T307I and E99K-T307I were approx. 140, 190 and 200%, respectively, of wild type beta-agarase (661 U/mg) at 40 degrees C.

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Flavonoids are known to be effective scavengers of free radicals. In particular, proanthocyanidins are flavonoids that possess cardiovascular protection, antioxidative activities, and immunomodulatory activities. Here, we evaluated proanthocyanidin contents in the total polyphenolic compounds of pine needle extracts prepared by hot water, ethanol, hexane, hot water-hexane (HWH), and hot water-ethanol (HWE).

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Whitening effect, tyrosinase inhibitions, and cytotoxicity of neoagarotetraose were measured after purification from hydrolyzed agar by gel filtration chromatography. In melanoma B16F10 cells, melanin content of neoagarotetraose-treated cells was as same as that treated by kojic acid or arbutin. In addition, tyrosinase of melanoma cells was strongly inhibited by neoagarotetraose at a concentration of 1 micron/ml and similarly inhibited at 10 and 100 microg/ml compared to those by arbutin or kojic acid.

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