https://repository.kopri.re.kr/handle/201206/5073 2026-03-05T14:51:24Z https://repository.kopri.re.kr/handle/201206/6325 Title: Isolation and spectral characterization of cadmium binding metallothionein Authors: Park, Hyun; Ji, Jung Youn; Ahn, In-Young; Choi, Heeseon J. Abstract: A cadmium (Cd)-binding protein was isolated and characterized from the Antarctic clam Laternula elliptica after experimental exposure to a high concentration of Cd. Cd-binding metallothioneins (MTs) in the cytosol were purified using a procedure based on gel permeation and ion-exchange chromatography. The purified MTs were recognized by MT antibodies in a Western blotting assay. MALDI-TOF MS analyses showed that the molecular mass of the purified MTs was 7.27 kDa, which is typical of MTs found in marine invertebrates. The Cd binding to MT, reflected by the redistribution of Cd ions, was monitored by spectrophotometry. The absorption spectra profiles indicated the presence of Cd-MT complexes, and a 4 nm red shift of the unresolved lowest energy-absorption band occurred when five equivalents of Cd (II) were incorporated. 2008-01-01T00:00:00Z https://repository.kopri.re.kr/handle/201206/6471 Title: Expression of heat shock protein 70 in the thermally stressed Antarctic clam Laternula elliptica Authors: Park, Hyun; Lee, Hye Eun; Ahn, In-Young Abstract: Heat shock protein 70 (designated Laternula elliptica Hsp70 (LEHsp70)) expression was investigated in an Antarctic mud clam to see whether or not the inducible heat shock response has been conserved throughout over 25 million years of adaptation to constant low environmental temperatures. LEHsp70 cDNA was cloned and sequenced from the Antarctic clam Latemula elliptica. We used degenerated primers designed in the highly conserved regions of Hsp to amplify the corresponding mRNA, and full-length cDNA was obtained by rapid amplification of cDNA ends (RACE). The full length of LEHsp70 cDNA was 2470 bp, with a 5' untranslated region (UTR) of 92 bp, a 3' UTR of 416 bp, and an open reading frame (ORF) of 1962 bp encoding a polypeptide of 653 amino acids with an estimated molecular mass of 71.266 kDa and an estimated isoelectric point of 5.20. LEHsp70 contained highly conserved functional motifs of the cytosolic Hsp70 family. Expression of the LEHsp70 gene was quantified by quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) of digestive gland and gill tissues. Heat shock (10 degrees C for different time periods) caused rapid induction of LEHsp70. A significant 4.6 +/- 0.14-fold increase in the LEHsp70/beta-Actin mRNA ratio occurred in the gill at 12 hours, which returned to baseline after 48 hours. In contrast, the maximum expression in the digestive gland (3.6 +/- 0.36) was reached at 24 hours and was still significant after 48 hours (1.89 +/- 0.21). This indicates that LEHsp70 may play an important role in mediating thermal stress and tolerance in this clam. 2007-01-01T00:00:00Z https://repository.kopri.re.kr/handle/201206/6140 Title: Vegetation of Barton Peninsula in the neighbourhood of King Sejong Station (King George Island, maritime Antarctic) Authors: Kim, Ji Hee; Choi, Han-Gu; Ahn, In-Young; Chung, Hosung; Lee, Kyu Song Abstract: Plant communities were studied on Barton Peninsula around King Sejong Station on King George Island, maritime Antarctic. The objective of this study was to document the occurrence and distribution of plant assemblages to provide the bases for monitoring the effects of environmental changes and human impact on the vegetation of this area. Approximately 47% of the investigated area was covered by vegetation. Crustose lichens showed the highest mean cover (21%) among vegetation components. The total mean cover of the four dominant taxa, together with the other three major subdominant components, i.e., Usnea spp., Andreaea spp. and Sanionia georgico-uncinata, was 78.2% of the total cover of all the species. Lichen cover and species diversity increased with altitude and the time of exposure from snow. Lichens contributed substantially more to the increased species density and diversity than did bryophytes. Ten plant communities were recognized within the study area. All of them belong to the Antarctic cryptogam tundra formation;they were grouped into four subformations: fruticose lichen and moss cushion subformation, crustose lichen subformation, moss carpet subformation and moss hummock subformation. The moss turf subformation was not found on this region. The Antarctic herb tundra formation was also not found;however, the populations of both Antarctic vascular plants have rapidly expanded around Barton Peninsula in recent years, which may allow development of the Antarctic herb tundra formation in the future. 2007-01-01T00:00:00Z https://repository.kopri.re.kr/handle/201206/6237 Title: Sequence, biochemical characteristics and expression of a novel Sigma-class of glutathione S-transferase from the intertidal copepod, Tigriopus japonicus with a possible role in antioxidant defense Authors: Lee, Yung Mi; Lee, Kyun-Woo; Park, Heum Gi; Ahn, In-Young; Sheikh Raisuddin; Park, Hyun; Lee, Jae-Seong Abstract: Glutathione S-transferases (GSTs) play a major role in detoxification of xenobiotics and antioxidant defense. Here we report full-length cDNA sequence of a novel Sigma-class of GST (GST-S) from the intertidal copepod Tigriopus japonicus. The full sequence was of 1136 bp in length containing an open reading frame (ORF) of 651 bp that encoded 217 amino acid residues. The recombinant Tigriopus GST-S was highly expressed in transformed Escherichia coli. Kinetic properties and effects of pH, temperature and chemical inhibitors on Tigriopus GST-S were also studied. The expression of GST-S was studied using real-time RT-PCR in response to exposure to two oxidative stresses-inducing agents, viz., hydrogen peroxide (H2O2) and heavy metals (copper, manganese). It was observed that H2O2 (2 mM) exposure down-regulated its expression at the initial stage but there was recovery and up-regulation shortly afterwards. In case of heavy metal exposure there was concentration-dependent increase in Tigriopus GST-S gene expression up to 24 h. These results suggest that Tigriopus GST-S expression is modulated by prooxidant chemicals and it may play a role against oxidative stress. A majority of other GST isoforms is known to play an important role in antioxidant defense. This study provides a preliminary insight into the possible antioxidant role for Sigma-class of GST in T japonicus. (c) 2007 Elsevier Ltd. All rights reserved. 2007-01-01T00:00:00Z