Lee S.,Sungkyunkwan University |
Jang H.-J.,Sungkyunkwan University |
Jang H.Y.,Sungkyunkwan University |
Hong S.,Sungkyunkwan University |
And 2 more authors.
Nanoscale | Year: 2016
We report a facile method to synthesize elongated nanoframes consisting of Pt and Au in solution. Pentagonal Au nanorods served as templates and successfully led to an elongated AuPt nanoframe after etching the core Au. Subsequently, the coating of Au around Pt ridges resulted in Pt@Au metal nanoframes. The resulting elongated nanostructure exhibited 5 well-defined ridges continuously connected along the long axis. During the shape evolution from pure Au nanorods to elongated Pt@Au metal nanoframes, their corresponding localized surface plasmon resonance bands were monitored. Especially, unique surface plasmon features were observed for elongated Pt@Au nanoframes where the short-axis oscillation of surface free electrons is strongly coupled but the long-axis oscillation is not coupled among the ridges. © The Royal Society of Chemistry 2016.
Tagad C.K.,University of Pune |
Kim H.U.,Sungkyunkwan University |
Aiyer R.C.,University of Pune |
More P.,University of Pune |
And 6 more authors.
RSC Advances | Year: 2013
The paper reports a rapid and single pot synthesis of polysaccharide stabilized silver nanoparticles (Ag NPs). The ability of Ag NPs to catalyze the reduction of hydrogen peroxide (H2O2) is successfully explored for the development of an optical fiber H2O2 sensor in the concentration range of 10-2 to 10-6 M. © 2013 The Royal Society of Chemistry.
Rastogi R.P.,Incheon National University |
Sinha R.P.,Banaras Hindu University |
Moh S.H.,Anti aging Research Institute of BIO FDandC Co. |
Lee T.K.,Korea Advanced Institute of Science and Technology |
And 7 more authors.
Journal of Photochemistry and Photobiology B: Biology | Year: 2014
Cyanobacteria are the dominant photosynthetic prokaryotes from an ecological, economical, or evolutionary perspective, and depend on solar energy to conduct their normal life processes. However, the marked increase in solar ultraviolet radiation (UVR) caused by the continuous depletion of the stratospheric ozone shield has fueled serious concerns about the ecological consequences for all living organisms, including cyanobacteria. UV-B radiation can damage cellular DNA and several physiological and biochemical processes in cyanobacterial cells, either directly, through its interaction with certain biomolecules that absorb in the UV range, or indirectly, with the oxidative stress exerted by reactive oxygen species. However, cyanobacteria have a long history of survival on Earth, and they predate the existence of the present ozone shield. To withstand the detrimental effects of solar UVR, these prokaryotes have evolved several lines of defense and various tolerance mechanisms, including avoidance, antioxidant production, DNA repair, protein resynthesis, programmed cell death, and the synthesis of UV-absorbing/screening compounds, such as mycosporine-like amino acids (MAAs) and scytonemin. This study critically reviews the current information on the effects of UVR on several physiological and biochemical processes of cyanobacteria and the various tolerance mechanisms they have developed. Genomic insights into the biosynthesis of MAAs and scytonemin and recent advances in our understanding of the roles of exopolysaccharides and heat shock proteins in photoprotection are also discussed. ©2014 Elsevier B.V. All rights reserved.
Lee J.H.,Korea Polar Research Institute |
Lee J.H.,Korean University of Science and Technology |
Park A.K.,Korea University |
Do H.,Korea Polar Research Institute |
And 7 more authors.
Journal of Biological Chemistry | Year: 2012
Arctic yeast Leucosporidium sp. produces a glycosylated ice-binding protein (LeIBP) with a molecular mass of ∼25 kDa, which can lower the freezing point below the melting point once it binds to ice. LeIBP is a member of a large class of ice-binding proteins, the structures of which are unknown. Here, we report the crystal structures of non-glycosylated LeIBP and glycosylated LeIBP at 1.57- and 2.43-Å resolution, respectively. Structural analysis of the LeIBPs revealed a dimeric right-handed β-helix fold, which is composed of three parts: a large coiled structural domain, a long helix region (residues 96-115 form a long α-helix that packs along one face of the β-helix), and a C-terminal hydrophobic loop region (243PFVPAPEVV 251). Unexpectedly, the C-terminal hydrophobic loop region has an extended conformation pointing away from the body of the coiled structural domain and forms intertwined dimer interactions. In addition, structural analysis of glycosylated LeIBP with sugar moieties attached to Asn185 provides a basis for interpreting previous biochemical analyses as well as the increased stability and secretion of glycosylated LeIBP. We also determined that the aligned Thr/Ser/Ala residues are critical for ice binding within the B face of LeIBP using site-directed mutagenesis. Although LeIBP has a common β-helical fold similar to that of canonical hyperactive antifreeze proteins, the ice-binding site is more complex and does not have a simple ice-binding motif. In conclusion, we could identify the ice-binding site of LeIBP and discuss differences in the ice-binding modes compared with other known antifreeze proteins and ice-binding proteins. © 2012 by The American Society for Biochemistry and Molecular Biology, Inc.
Doan K.V.,Yonsei University |
Ko C.M.,Yonsei University |
Kinyua A.W.,Yonsei University |
Yang D.J.,Yonsei University |
And 16 more authors.
Endocrinology | Year: 2015
Gallic acid [3,4,5-trihydroxybenzoic acid (GA)], a natural phytochemical, is known to have a variety of cellular functions including beneficial effects on metabolic syndromes. However, the molecular mechanism by whichGAexerts its beneficial effects is not known. Herewereport thatGAplays its role through the activation of AMP-Activated protein kinase (AMPK) and by regulating mitochondrial function via the activation of peroxisome proliferator-Activated receptor-γ coactivator1α (PGC1α). Sirtuin 1 (Sirt1) knockdown significantly blunted GA's effect on PGC1α activation and downstream genes, suggesting a critical role of the AMPK/Sirt1/PGC1α pathway in GA's action. Moreover, dietinduced obese mice treated with GA showed significantly improved glucose and insulin homeostasis. In addition, the administration of GA protected diet-induced body weight gain without a change in food intake. Biochemical analyses revealed a marked activation of AMPK in the liver, muscle, and interscapular brown adipose tissue of the GA-treated mice. Moreover, uncoupling protein 1 together with other genes related to energy expenditure was significantly elevated in the interscapular brown adipose tissue. Taken together, these results indicate that GA plays its beneficial metabolic roles by activating the AMPK/Sirt1/PGC1α pathway and by changing the interscapular brown adipose tissue genes related to thermogenesis. Our study points out that targeting the activation of the AMPK/Sirt1/PGC1α pathway by GA or its derivatives might be a potential therapeutic intervention for insulin resistance in metabolic diseases. © 2015 by the Endocrine Society.
Lee J.,Hanyang University |
Moh S.-H.,Anti Aging Research Institute of Bio FD and C Co. |
Ryou C.,Hanyang University |
Kim D.-H.,Hanyang University
Korean Journal of Microbiology and Biotechnology | Year: 2015
Prions are proteinaceous infectious particles that cause neurodegenerative diseases, such as scrapie in sheep, bovine spongiform encephalopathy in cattle and Creutzfeldt-Jakob disease (CJD) in humans. Although the detailed process, regarding the abnormal conversion of prion proteins (PrP), remains to be fully elucidated, a number of environmental factors appear to affect the formation of misfolded PrP, termed PrPSc. Because oceanic algae contain mycosporine-like amino acids (MAAs), which exhibit cellular defensive activities under a variety of stress conditions, we investigated the level of PrPSc in prion-infected neuroblastoma cells using mycosporine-glycine, porphyra-334 and shinorine. When judged by the level of protease-resistant PrPSc in western blots, porphyra-334 and shinorine increased the level of PrPSc in cells, but mycosporine-glycine did not. The current results indicate that the MAAs tested in this study enhance the formation of PrPSc. © 2015, The Korean Society for Microbiology and Biotechnology.
Kulkarni A.,Antiaging Research Institute of BIO FDandC Co. |
Lee J.H.,Antiaging Research Institute of BIO FDandC Co. |
Seo H.H.,Antiaging Research Institute of BIO FDandC Co. |
Kim H.-S.,Antiaging Research Institute of BIO FDandC Co. |
And 4 more authors.
Materials Chemistry and Physics | Year: 2015
Mycosporine-like amino acids (MAAs) are an important group of novel bioactive compounds having immense biotechnological potentials due to their UV screening properties and antioxidant activities. However, their photoelectric properties were not evaluated yet. In the present work two types of MAAs Shinorine and Porphyra-334, were extracted from algae; Chlamydomonas hedlyei and Porphyra yezoensis respectively and its electrical transport properties were investigated upon illumination of UV light. The combination of optical absorption and electron transport measurement of MAAs in a field effect transistor device reveals that these changes are mainly due to the carboxyl group present in MAAs. This study reports a platform technology for the development of novel biochemical-electrical devices. © 2014 Elsevier B.V. All rights reserved.
Chon Y.J.,Soongsil University |
Jung H.S.,Anti aging Research Institute of BIO FD and C Co. |
Kim H.S.,Anti aging Research Institute of BIO FD and C Co. |
Lee J.H.,Anti aging Research Institute of BIO FD and C Co. |
Moh S.H.,Anti aging Research Institute of BIO FD and C Co.
Journal of Applied Biological Chemistry | Year: 2016
As natural plant-based industry has been expanded, the use of oriental medicinal plants as cosmeceutical material received a lot of attentions in the cosmetic industry. Among various medicinal plants, Potentilla chinensis have drawn interests for its biological effects. Although several attempts were tried to study its biological effect as medicinal plant, only limited results were reported to evaluate its biological effect as cosmeceutical material. In this study, we examined the possibility of root extract from Potentilla chinensis as a cosmeceutical material because the root part has been reported to have several kinds of health promoting effects. After extraction of roots, biological evaluation including anti-inflammation, anti-wrinkle, whitening effect and moisturizing effect was performed. As a result, the root extract showed remarkable biological activities through stimulating synthesis of elastin and aquaporin-3, and inhibiting melanin synthesis, cyclooxygenase-2 expression and expression of metallopeptidase-1. © The Korean Society for Applied Biological Chemistry 2016.
Khanh D.V.,Yonsei University |
Choi Y.-H.,Yonsei University |
Choi Y.-H.,Antiaging Research Institute of BIO FD and C Co. |
Moh S.H.,Antiaging Research Institute of BIO FD and C Co. |
And 2 more authors.
Frontiers in Psychology | Year: 2014
The central actions of leptin and insulin are essential for the regulation of energy and glucose homeostasis. In addition to the crucial effects on the hypothalamus, emerging evidence suggests that the leptin and insulin signaling can act on other brain regions to mediate the reward value of nutrients. Recent studies have indicated the midbrain dopaminergic neurons as a potential site for leptin' and insulin's actions on mediating the feeding behaviors and therefore affecting the energy balance. Although molecular details about the integrative roles of leptin and insulin in this subset of neurons remain to be investigated, substantial body of evidence by far imply that the signaling pathways regulated by leptin and insulin may play an essential role in the regulation of energy balance through the control of food-associated reward. This review therefore describes the convergence of energy regulation and reward system, particularly focusing on leptin and insulin signaling in the midbrain dopaminergic neurons. © 2014 Khanh, Choi, Moh, Kinyua and Kim.
Suh S.-S.,Korea Advanced Institute of Science and Technology |
Hwang J.,Korea Advanced Institute of Science and Technology |
Park M.,Korea Advanced Institute of Science and Technology |
Seo H.H.,Anti Aging Research Institute of Bio FD and C Co. |
And 4 more authors.
Marine Drugs | Year: 2014
Certain photosynthetic marine organisms have evolved mechanisms to counteract UV-radiation by synthesizing UV-absorbing compounds, such as mycosporine-like amino acids (MAAs). In this study, MAAs were separated from the extracts of marine green alga Chlamydomonas hedleyi using HPLC and were identified as porphyra-334, shinorine, and mycosporine-glycine (mycosporine-Gly), based on their retention times and maximum absorption wavelengths. Furthermore, their structures were confirmed by triple quadrupole MS/MS. Their roles as UV-absorbing compounds were investigated in the human fibroblast cell line HaCaT by analyzing the expression levels of genes associated with antioxidant activity, inflammation, and skin aging in response to UV irradiation. The mycosporine-Gly extract, but not the other MAAs, had strong antioxidant activity in the 2,2-diphenyl-1-picryhydrazyl (DPPH) assay. Furthermore, treatment with mycosporine-Gly resulted in a significant decrease in COX-2 mRNA levels, which are typically increased in response to inflammation in the skin, in a concentration-dependent manner. Additionally, in the presence of MAAs, the UV-suppressed genes, procollagen C proteinase enhancer (PCOLCE) and elastin, which are related to skin aging, had increased expression levels equal to those in UV-mock treated cells. Interestingly, the increased expression of involucrin after UV exposure was suppressed by treatment with the MAAs mycosporine-Gly and shinorine, but not porphyra-334. This is the first report investigating the biological activities of microalgae-derived MAAs in human cells. © 2014 by the authors; licensee MDPI, Basel, Switzerland.