https://repository.kopri.re.kr/handle/201206/8 Sun, 05 Apr 2026 19:21:09 GMT 2026-04-05T19:21:09Z https://repository.kopri.re.kr/handle/201206/9088 Title: The idea of practical strategies regarding polar oceans: by analyzing policies of major countries and international institutes Authors: Hwang, JinHoe Thu, 20 Jul 2017 00:00:00 GMT https://repository.kopri.re.kr/handle/201206/9088 2017-07-20T00:00:00Z https://repository.kopri.re.kr/handle/201206/5811 Title: Enzymatic modification by point mutation and functional analysis of an omega-6 fatty acid desaturase from Arctic Chlamydomonas sp. Authors: Jung, Woongsic; Kim, Sanghee; Choi, Han-Gu; Kang, Sung-Ho; Han, Se Jong; Kim, Eun Jae Abstract: Arctic Chlamydomonas sp. is a dominant microalgal strain in cold or frozen freshwater in the Arctic region. The full-length open reading frame of the omega-6 fatty acid desaturase gene (AChFAD) was obtained from the transcriptomic database of Arctic Chlamydomonas sp. from the KOPRI Culture Collection of Polar Microorganisms (KCCPM). Amino acid sequence analysis indicated the presence of three conserved histidine-rich segments as unique characteristics of omega-6 FADs, and three transmembrane regions transported to plastidic membranes by chloroplast transit peptides in the N-terminal region. The AChFAD6 desaturase activity was examined by expressing wild-type and V254A mutant (Mut-AChFAD6) heterologous recombinant proteins. Quantitative gas chromatography indicated that the concentration of linoleic acids in AChFAD6-transformed cells increased more than three-fold (6.73 ± 0.13 mg g-1 dry cell weight (DCW)) compared with cells transformed with vector alone. In contrast, transformation with Mut-AChFAD6 increased the concentration of oleic acid to 9.23 ± 0.18 mg g-1 DCW, indicating a change in enzymatic activity to mimic that of stearoyl-CoA desaturase (SCD). These results demonstrate that AChFAD6 of Arctic Chlamydomonas sp. increases membrane fluidity by enhancing desaturating C18 fatty acids and facilitates production of large quantities of linoleic fatty acids in prokaryotic expression systems. Sun, 01 Jan 2017 00:00:00 GMT https://repository.kopri.re.kr/handle/201206/5811 2017-01-01T00:00:00Z https://repository.kopri.re.kr/handle/201206/5768 Title: Lithostratigraphy and paleoceanography in the Chukchi Rise of the western Arctic Ocean since the last glacial period Authors: Keun, Khim Boo; Hyen Goo Cho; Ken'ichi Ohkushi; Park, Kwangkyu Abstract: Paleoceanographic multi-proxies were investigated from two piston cores PC01 and PC04, along with two pilot cores PL01 and PL04, collected from the Chukchi Rise in the western Arctic Ocean during the R/V Mirai Cruise MR09-03. Both cores were composed of three lithologic units (Unit I: the Holocene brownish sandy mud, Unit II: the deglacial IRD layer, and Unit III: the glacial and gray thick mud with intervened IRD layers). The age estimate of the core units were decided by AMS 14C dates and confirmed by the correlation of the geochemical properties and ice-rafted debris (IRD) pattern with the well-dated core (P2) in the study area. The geochemical, isotopic, and mineralogical properties indicate different paleoceanographic conditions of three lithologic units in the Chukchi Rise: low primary production during the glacial period (Unit III), high terrigenous contribution during the deglacial period (Unit II), and increase in diatom productivity during the late Holocene (Unit I). In particular, most IRDs were specified as detrital carbonates (calcites and dolomites) by SEM-EDS examination. The sediment source from the northern North America and the transport pathway by the Beaufort Gyre were confirmed by the isotopic signature of bulk IRDs and high kaolinite content of fine-grained particles. Sun, 01 Jan 2017 00:00:00 GMT https://repository.kopri.re.kr/handle/201206/5768 2017-01-01T00:00:00Z https://repository.kopri.re.kr/handle/201206/8993 Title: Investigation of fluorescence characteristics and concentration distribution of dissolved organic matterin the Arctic Ocean Authors: Shin, Kyung-Hoon Tue, 02 Aug 2016 00:00:00 GMT https://repository.kopri.re.kr/handle/201206/8993 2016-08-02T00:00:00Z