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Collection and screening of bioactive compounds from the microbial diversity of polar environments

Thu, 31 Jan 2019 00:00:00 GMT

Title: Collection and screening of bioactive compounds from the microbial diversity of polar environments Authors: 손재학

Immunomodulatory activities of biological extracts from bi-polar ocean

Wed, 30 Jan 2019 00:00:00 GMT

Title: Immunomodulatory activities of biological extracts from bi-polar ocean Authors: 표석능

Effects of temperature shifts on life parameters and expression of fatty acid synthesis and heat shock protein genes in temperate and Antarctic copepods Tigriopus japonicus and Tigriopus kingsejongensis

Sat, 01 Dec 2018 00:00:00 GMT

Title: Effects of temperature shifts on life parameters and expression of fatty acid synthesis and heat shock protein genes in temperate and Antarctic copepods Tigriopus japonicus and Tigriopus kingsejongensis Authors: Han, Jeonghoon; Lee, Min-Chul; Park, Jun Chul; Kim, Sanghee; Lee, Jae-Seong Abstract: Global warming, increase of the atmospheric temperature leading to changes in climate, is a growing environmental concern for all organisms including marine organisms, and many efforts have been made to reveal the potential adverse effects on the systematics of aquatic organisms in response to the temperature changes. To examine the effects of temperature shifts on copepods in temperate and polar regions, we compared the life parameters and gene expression profiles of the de novo lipogenesis (DNL) pathway and heat shock protein (hsp) genes in the temperate copepod Tigriopus japonicus (T. japonicus) and the Antarctic copepod Tigriopus kingsejongensis (T. kingsejongensis). The median lethal temperature (LT50) and no observed effect level (NOEL) in the temperate copepod T. japonicus were determined to be 35.3 and 32 °C, respectively, in response to a temperature increase of 2 °C a day. In the Antarctic copepod T. kingsejongensis, the LT50 and NOEL were determined to be 24.8 and 12 °C, respectively. In addition, delayed developmental time and impaired fecundity were observed (P < 0.05) in response to temperature changes in T. japonicus. T. japonicus DNL pathway genes were down-regulated in response to high temperature, whereas T. kingsejongensis DNL pathway genes showed up-regulation in response to high temperature, indicating that these two Tigriopus species have different modes of action in response to temperature shifts. In both copepods, transcription of heat shock proteins (hsps) was mostly up-regulated in response to temperature shifts, but it showed moderate expression at 15 °C for T. japonicus and 4 °C for T. kingsejongensis. These findings indicate temperature shift-mediated species-specific modulations of the DNL pathway and hsps gene expression, leading to alteration of lipid synthesis and chaperoning with deleterious effects on the life parameters of these two copepods.

Chemical constituents from the Antarctic lichen, Stereocaulon caespitosum

Mon, 01 Oct 2018 00:00:00 GMT

Title: Chemical constituents from the Antarctic lichen, Stereocaulon caespitosum Authors: Youn, Ui Joung; Yim, Joung Han; Kim, Il-Chan; Park, Hyun; Han, Se Jong; Kim, Ji Hee; So, Jae Eun Abstract: A phytochemical study of the methanol extract of the Antarctic lichen Stereocaulon caespitosum Redgr. led to the isolation of a tridepside (1), two depsides (2 and 3), a montagnetol derivative (4), and four mono-phenolic compounds (5？8). The structures of these compounds were confirmed by 1D- and 2D- nuclear magnetic resonance (NMR) experiments, as well as by comparison with published values. This is the first phytochemical study of S. caespitosum. In particular, compounds 1, 3, 4, and 8 have been isolated for the first time from the genus Stereocaulon and the family Stereocaulaceae. The chemotaxonomic significance of the isolated compounds is discussed.