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Seung Hyuck Bang,Ji-Young Ahn,Nam-Hui Hong,Simranjeet Singh Sekhon,Yang-Hoon Kim,Jiho Min 대한독성 유전단백체 학회 2015 Molecular & cellular toxicology Vol.11 No.2
The exposure of environment to pharmaceuticals disturbs the aquatic ecosystem. In this study, the effect of commonly used pharmaceutical compounds such as caffeine, ibuprofen, aspirin, and tetracycline has been investigated by the toxicity assay using Daphnia magna. The acute (48 h) and chronic (21 days) toxicity assays have been performed using Daphnia magna. The lethal concentrations of caffeine, ibuprofen, aspirin, and tetracycline with 50% mortality (LC50) have been determined as ~445.3, 91.5, 310, and 90.8 mg/L, respectively. In the chronic toxicity test, low concentrations such as 1%, 2%, 10%, 20% LC50 of the pharmaceuticals were used to expose the organisms for 21 days. The effect of these pharmaceuticals on the molecular responses in the organisms has been studied from the gene expression level of five different biomarkers in Daphnia magna (Dhb, Vtg, Arnt, CYP4, and CYP314) after 48 h and 21 days exposure to the testing pharmaceuticals. The results show that five genes show different responsive patterns when Daphnia magna was under stressful conditions caused by caffeine, ibuprofen, aspirin, and tetracycline. During exposure to caffeine, only the response for the Dhb gene increased in the acute test, whereas all other genes, except Dhb gene, were down regulated in the chronic text. In contrast, in the acute and chronic toxicity test for ibuprofen, the responses for Arnt and CYP4 genes were reduced, respectively. Moreover, after 48 h exposure to aspirin, all other genes, except the Dhb gene, were down regulated. In the chronic test using tetracycline, five genes expression of D. magna were affected.
( Seung Hyuck Bang ),( Pil Kim ),( Suk Jung Oh ),( Yang Hoon Kim ),( Ji Ho Min ) 한국미생물 · 생명공학회 2015 Journal of microbiology and biotechnology Vol.25 No.5
Techniques for immobilizing effective enzymes on nanoparticles for stabilization of the activity of free enzymes have been developing as a pharmaceutical field. In this study, we examined the effect of three different pH conditions of phosphate buffer, as a dissolving solvent for lysosomal enzymes, on the direct immobilization of lysosomal enzymes extracted from Hen’s egg white and Saccharomyces cerevisiae. Titanium(IV) oxide (TiO2) nanoparticles, which are extensively used in many research fields, were used in this study. The lysosomal enzymes immobilized on TiO2 under each pH condition were evaluated to maintain the specific activity of lysosomal enzymes, so that we can determine the degree of melanin treatment in lysosomal enzymes immobilized on TiO2. We found that the immobilization efficiency and melanin treatment activity in both lysosomal enzymes extracted from Hen’s egg white and S. cerevisiae were the highest in an acidic condition of phosphate buffer (pH 4). However, the immobilization efficiency and melanin treatment activity were inversely proportional to the increase in pH under alkaline conditions. In addition, enhanced immobilization efficiency was shown in TiO2 pretreated with a divalent, positively charged ion, Ca2+, and the melanin treatment activity of immobilized lysosomal enzymes on TiO2 pretreated with Ca2+ was also increased. Therefore, this result suggests that the immobilization efficiency and melanin treatment activity of lysosomal enzymes can be enhanced according to the pH conditions of the dissolving solvent.
Toxicity Assessment of Titanium (IV) Oxide Nanoparticles Using Daphnia magna (Water Flea)
Bang, Seung-Hyuck,Le, Thai-Hoang,Lee, Sung-Kyu,Kim, Pil,Kim, Jong-Soo,Min, Ji-Ho The Korean Society of Environmental Toxicology 2011 환경독성보건학회지 Vol.26 No.-
Objectives: Titanium dioxide ($TiO_2$), a common nanoparticle widely used in industrial production, is one of nano-sized materials. The purpose of this study was to determine the acute and chronic toxicity of $TiO_2$ using different size and various concentrations on Daphnia magna. Methods: In the acute toxicity test, four concentrations (0, 0.5, 4, and 8 mM) for $TiO_2$ with 250 or 500 nm and five concentrations (0, 0.25, 0.5, 0.75, and 1 mM) for $TiO_2$ with 21 nm were selected to analyze the toxic effect to three groups of ten daphnia neonates over 96 hours. In addition, to better understand their toxicity, chronic toxicity was examined over 21 days using 0, 1, and 10 mM for each type of $TiO_2$. Results: Our results showed that all organisms died before the reproduction time at a concentration of 10 mM of $TiO_2$. In addition, the exposure of anatase (21 nm) particles were more toxic to D. magna, comparing with that of anatase (250 nm) and rutile (500 nm) particles. Conclusions: This study indicated that $TiO_2$ had adverse impacts on the survival, growth and reproduction of D. magna after the 21days exposure. In addition, the number of test organisms that were able to reproduce neonates gradually were reduced as the size of $TiO_2$ tested was decreased.
Advances in antimicrobial agents based lysosomes
Bang, Seung Hyuck,Sekhon, Simranjeet Singh,Ahn, Ji-Young,Kim, Yang-Hoon,Min, Jiho 대한독성유전단백체학회 2014 Molecular & cellular toxicology Vol.10 No.3
The emergence of drug resistance in common bacteria and the rapid emergence of new infections have motivated the need for the development of eco-friendly agents that do not contain any organic or inorganic material. The development of therapeutic agents which are able to remove or treat bacteria and cancer cell is very important and it should be very rapid, cost effective and nontoxic. Lysosomes are important against all other subcellular constituents due to their polymorphism as well as their involvement in both physiological and pathological processes. Lysosomes, which generally contain 50-60 hydrolases that constitute the cellular site for bulk macromolecule degradation, function to mediate several processes in the cell. They are single membrane bound cytoplasmic organelles involved in the degradation of intracellular protein. Lysosomal enzymes in lysosomes can be used as endocytosis for inhibiting bacteria phagocytosis as well as in antimicrobial activity. Many attempts have been made to increase the lysosomal activity by using different sources and significant changes have been observed in lysosome activity under starvation condition of reduced glucose. The treatment of some of the reagents and optimized aging cell with cell passage has also been used to evaluate an increase in their antimicrobial activity. The antimicrobial activity of lysosomes with various bacteria extracted from different sources has been observed. In the present review, the antimicrobial activity of lysosomes isolated from various sources such as human, bacteria and animals against different microorganisms has been discussed.
Analysis of lysosomal membrane proteins exposed to melanin in HeLa cells
Bang, Seung Hyuck,Park, Dong Jun,Kim, Yang-Hoon,Min, Jiho The Korean Society of Environmental Toxicology 2016 환경독성보건학회지 Vol.31 No.-
Objectives There have been developed to use targeting ability for antimicrobial, anticancerous, gene therapy and cosmetics through analysis of various membrane proteins isolated from cell organelles. Methods It was examined about the lysosomal membrane protein extracted from lysosome isolated from HeLa cell treated by 100 ppm melanin for 24 hours in order to find associated with targeting ability to melanin using by 2-dimensional electrophoresis. Results The result showed 14 up-regulated (1.5-fold) and 13 down-regulated (2.0-fold) spots in relation to melanin exposure. Conclusions It has been found that lysosomal membrane proteins are associated with melanin to decolorize and quantity through cellular activation of lysosome.