Graphene Oxide-mediated Fluorescence Quenching of Green Fluorescent Protein for Biomedical Applications

Lan-Huong TRAN,이창우,강태종,장세헌 대한화학회 2016 Bulletin of the Korean Chemical Society Vol.37 No.8

We investigated the fluorescence property of green fluorescent protein (GFP) with graphene oxide (GO) for both non-covalent and covalent interactions. The mechanism of GO-mediated quenching of GFP fluorescence is the combination of both static and dynamic quenching. Although GFP exhibits two absorption bands with similar fluorescence emission spectra, the quenching efficiency of the two absorption bands from non-covalent immobilization were different—one with absorption at 460 nm, showing a higher fluorescence resonance transfer efficiency than the other absorption at 395 nm. We determined the apparent Stern–Volmer quenching constant (Kapp) of GFP for GO to be 2.6 × 10−7 mL/g. However, GFP fluorescence disappeared upon covalent immobilization on GO.

Using Online Respondent Driven Sampling for Vietnamese Youths’ Alcohol Use and Associated Risk Factors

Melvyn WB Zhang,Bach Xuan Tran,Huong Lan Thi Nguyen,Huong Thi Le,Nguyen Hoang Long,Huong Thi Le,Nguyen Duc Hinh,Tran Dinh Tho,Bao Nguyen Le,Vu Thi Minh Thuc,Chau Ngo,Nguyen Huu Tu,Carl A. Latkin,Roger 대한의료정보학회 2017 Healthcare Informatics Research Vol.23 No.2

Objectives: The average alcohol consumption per capita among Vietnamese adults has consistently increased. Although alcoholrelated disorders have been extensively studied, there is a paucity of research shedding light on this issue among Internet users. The study aimed to examine the severity of alcohol-related disorders and other associated factors that might predispose individuals towards alcohol usage in a sample of youths recruited online. Methods: An online cross-sectional study was conducted with 1,080 Vietnamese youths. A standardized questionnaire was used. Respondent-driven sampling was applied to recruit participants. Multivariate logistic and Tobit regressions were utilized to identify the associated factors. Results: About 59.5% of the males and 12.7% of the total youths declared that they were actively using alcohol. From the total sample, a cumulative total of 32.3% of the participants were drinking alcohol, with 21.8% and 25.0% of the participants being classified as drinking hazardously and binge drinkers, respectively. The majority of the participants (60.7%) were in the pre-contemplative stage. Conclusions: A high prevalence of hazardous drinking was recognized among online Vietnamese youths. In addition, we found relationships between alcohol use disorder and other addictive disorders, such as tobacco smoking and water-pipe usage. Our results highlighted that the majority of the individuals are not receptive to the idea of changing their alcohol habits, and this would imply that there ought to be more government effort towards the implementation of effective alcohol control policies.

Environmental-friendly method for preparing CoFe2O4 coated biopolymer extracted from dragon fruit peel: Characterization and application as nanocomposite adsorbent for removal of As(III) pollutants from aqueous solution

Lan Huong Nguyen,Van Son Le,Luu Dung Tran,Nam Van Thai,Ho Thi Ngoc Tram,Bui Quang Minh,Van Huy Nguyen 한국공업화학회 2023 Journal of Industrial and Engineering Chemistry Vol.118 No.-

This study successfully developed a low-cost adsorbent from compositing between magnetic nanoparticle(CoFe2O4) and dragon fruit peel-derived biopolymer (DFP-BP) and applied it to remove arsenite (As(III)) from contaminated water. The batch experiments were designed to study the influence of operationalparameters on As(III) adsorption by nanocomposite (CoFe2O4@DFP-BP). With mapping analysis,the synthesized CoFe2O4@DFP-BP was characterized using SBET, SEM, FTIR, XRD, and EDS mapping. TheAs(III) adsorption mechanism was discussed based on material property data and isotherm and kineticanalysis. The result suggests that 5% is the best modification ratio on the CoFe2O4@DFP-BP for As(III)adsorption. The highest adsorption capacity of As(III) under the optimal conditions of pH 7, adsorbentdosage of 1.6 g/L, initial As(III) concentration of 2000 lg/L and the best described by the Sips modelwas 1922.7 lg/g. The adsorption kinetic followed pseudo-second-order, proving As(III) adsorption processcontrolled by chemisorption. The primary reaction pathway of As(III) adsorption on theCoFe2O4@DFP-BP5 was inner-sphere complexation through exchange between the nanoadsorbent’s surfaceand As(III) ions via oxygen-containing functional (carboxyl and hydroxyl) groups. The CoFe2O4 magneticnanoparticles coated by biopolymer overcame drawbacks, including low stability and mechanicalstrength of biopolymer and agglomerate trend of magnetic nanoparticles. The adsorption process washighly reversible and accessible in the separation of nanoadsorbent after adsorption by the magnet. Therefore, the nanocomposite formed from solid waste has excellent potential as a material for removingAs, contributing to sustainable development and feasibility in practical application.

Molecular Interactions of Graphene Oxide with Aromatic Amino Acids Tyrosine and Tryptophan

우진국,Lan-Huong TRAN,장세헌,이창우,강태종 대한화학회 2015 Bulletin of the Korean Chemical Society Vol.36 No.12

<i>Paracoccus</i> <i>panacisoli</i> sp. nov., isolated from a forest soil cultivated with Vietnamese ginseng

Nguyen, Ngoc-Lan,Kim, Yeon-Ju,Hoang, Van-An,Tran, Bao-Tram,Pham, Huong-Son,Yang, Deok-Chun International Union of Microbiological Societies 2015 International journal of systematic and evolutiona Vol.65 No.5

<P>A novel bacterial strain, designated DCY94<SUP>T</SUP>, was isolated from forest soil cultivated with ginseng in Vietnam. The strain was Gram-reaction-negative, facultatively anaerobic, non-motile, rod-shaped and catalase- and oxidase-positive. 16S rRNA gene sequence analysis demonstrated that strain DCY94<SUP>T</SUP> was closely related to <I>Paracoccus sphaerophysae</I> Zy-3<SUP>T</SUP> (97.5 % 16S rRNA gene sequence similarity) and <I>Paracoccus caeni</I> MJ17<SUP>T</SUP> (96.9 %). The fatty acid profile of strain DCY94<SUP>T</SUP> contained a predominant amount of summed feature 8 (C<SUB>18 : 1</SUB>ω7<I>c</I> and/or C<SUB>18 : 1</SUB>ω6<I>c</I>; 88.4 %) and moderate to small quantities of C<SUB>8 : 0</SUB> 3-OH (1.0 %), C<SUB>10 : 0</SUB> 3-OH (2.8 %) and C<SUB>18 : 0</SUB> (5.2 %). Phosphatidylethanolamine, phosphatidylglycerol, phosphatidylcholine and one unidentified glycolipid were major polar lipids; one unidentified aminolipid, one unidentified aminophospholipid, one unidentified phospholipid and four unidentified polar lipids were minor components. The polyamine pattern comprised the major compounds putrescine and spermidine and minor amounts of <I>sym</I>-homospermidine and spermine. The ubiquinone of the strain was Q-10 and the G+C content of its genomic DNA was 68.3 mol%. All these results support the placement of strain DCY94<SUP>T</SUP> within the genus <I>Paracoccus</I> . Levels of DNA–DNA relatedness between strain DCY94<SUP>T</SUP> and <I>P. sphaerophysae</I> HAMBI 3106<SUP>T</SUP> and <I>P. caeni</I> KCTC 22480<SUP>T</SUP> were 52 and 50 %, respectively. The results of phylogenetic analysis, phenotypic tests, chemotaxonomic characterization and DNA–DNA relatedness studies distinguished strain DCY94<SUP>T</SUP> from the closest recognized species of the genus <I>Paracoccus</I> , suggesting that this strain represents a novel species, for which the name <I>Paracoccus panacisoli</I> sp. nov. is proposed. The type strain is DCY94<SUP>T</SUP> ( = KCTC 42086<SUP>T</SUP> = JCM 30337<SUP>T</SUP>).</P>

Tyrosine and Tryptophan Have Different Binding Sites on Graphene Oxide

Byeong June Min,Lan-Huong TRAN,Sei-Heon Jang,ChangWoo Lee 한국물리학회 2016 새물리 Vol.66 No.1

Graphene oxide (GO) has attracted much attention for biomedical applications. Amino acids are known to interact with GO, but their binding sites on GO are largely unraveled. Here, by using an $ab~initio$ molecular dynamics simulations and fluorescence quenching experiments, we show that the aromatic amino acids tyrosine and tryptophan have different binding sites on GO. Tyrosine prefers localization near the functional groups of GO including alcohols, epoxides, and carboxylic acids whereas tryptophan prefers localization near the plain GO surface. Although Tyr and Trp have similar binding energies, more Trp binds to GO than Tyr does due to the large surface area of GO. Our study provides a novel insight into the localization of aromatic amino acids on the surface of GO.

Lipid Hydrolysis Catalyzed by Graphene Oxide

Hong-Nhung Trinh,Lan-Huong TRAN,이창우,장세헌 대한화학회 2017 Bulletin of the Korean Chemical Society Vol.38 No.12

Graphene oxide (GO) is a two-dimensional carbon nanomaterial. It has oxygen-containing functional groups, including alcohols, epoxides, and carboxylic acids. Herein, we show that GO catalyzes the hydrolysis of typical lipid molecules—phospholipids, triacylglycerols, sphingomyelins, and cholesterol esters—at temperatures above 50 °C. Ester bonds at both 1- and 2-positions of phosphatidylcholine were hydrolyzed by GO, indicating that the hydrolysis reaction is non-regiospecific in nature. GO-mediated lipid hydrolysis was facilitated by ethanol with maximal activity at 60% ethanol, whereas lipid hydrolysis by porcine pancreatic lipase showed maximal activity at 30% ethanol. The catalytic efficiency of recovered GO for phosphatidylcholine hydrolysis was approximately 80% up to four cycles.

Regulation of expression of matrix metalloproteinase-9 by JNK in Raw 264.7 cells: presence of inhibitory factor(s) suppressing MMP-9 induction in serum and conditioned media

Yun-Song Lee,Huong Thi Lan Tran,Quang Van Ta 생화학분자생물학회 2009 Experimental and molecular medicine Vol.41 No.4

Matrix metalloproteinase-9 (MMP-9) secreted from macrophages plays an important role in tissue destruction and inflammation through degradation of matrix proteins and proteolytic activation of cytokines/ chemokines. Whereas the MEK-ERK and PI3KAkt pathways up-regulate MMP-9 expression, regulation of MMP-9 by JNK remains controversial. Presently, we aimed to determine the role of JNK in MMP-9 regulation in Raw 264.7 cells. Inhibition of JNK by the JNK inhibitor SP600125 induced MMP-9 in the absence of serum and suppressed the expression of TNF-α, IL-6 and cyclooxygenase-2 in LPS-treated Raw 264.7 cells. In a knockdown experiment with small interfering RNA, suppression of JNK1 induced MMP-9 expression. Interestingly, mouse serum suppressed SP600125- mediated MMP-9 induction, similar to IFN-γ. However, the inhibitory activity of mouse serum was not affected by pyridone 6, which inhibits Janus kinase downstream to IFN-γ. In addition to mouse serum, conditioned media of Raw 264.7 cells contained the inhibitory factor(s) larger than 10 kDa, which suppressed SP600125- or LPS-induced MMP-9 expression. Taken together, these data suggest that JNK1 suppresses MMP-9 expression in the absence of serum. In addition, the inhibitory factor(s) present in serum or secreted from macrophages may negatively control MMP-9 expression. Matrix metalloproteinase-9 (MMP-9) secreted from macrophages plays an important role in tissue destruction and inflammation through degradation of matrix proteins and proteolytic activation of cytokines/ chemokines. Whereas the MEK-ERK and PI3KAkt pathways up-regulate MMP-9 expression, regulation of MMP-9 by JNK remains controversial. Presently, we aimed to determine the role of JNK in MMP-9 regulation in Raw 264.7 cells. Inhibition of JNK by the JNK inhibitor SP600125 induced MMP-9 in the absence of serum and suppressed the expression of TNF-α, IL-6 and cyclooxygenase-2 in LPS-treated Raw 264.7 cells. In a knockdown experiment with small interfering RNA, suppression of JNK1 induced MMP-9 expression. Interestingly, mouse serum suppressed SP600125- mediated MMP-9 induction, similar to IFN-γ. However, the inhibitory activity of mouse serum was not affected by pyridone 6, which inhibits Janus kinase downstream to IFN-γ. In addition to mouse serum, conditioned media of Raw 264.7 cells contained the inhibitory factor(s) larger than 10 kDa, which suppressed SP600125- or LPS-induced MMP-9 expression. Taken together, these data suggest that JNK1 suppresses MMP-9 expression in the absence of serum. In addition, the inhibitory factor(s) present in serum or secreted from macrophages may negatively control MMP-9 expression.

Spilanthes acmella inhibits inflammatory responses via inhibition of NF-κB and MAPK signaling pathways in RAW 264.7 macrophages

Cho, Young-Chang,Bach, Tran The,Kim, Ba Reum,Vuong, Huong Lan,Cho, Sayeon SPANDIDOS PUBLICATIONS 2017 MOLECULAR MEDICINE REPORTS Vol.16 No.1

Synthesis, bioevaluation and docking study of 5-substitutedphenyl-1,3,4-thiadiazole-based hydroxamic acids as histone deacetylase inhibitors and antitumor agents

Nam, Nguyen-Hai,Huong, Tran Lan,Dung, Do Thi Mai,Dung, Phan Thi Phuong,Oanh, Dao Thi Kim,Park, Sang Ho,Kim, Kyungrok,Han, Byung Woo,Yun, Jieun,Kang, Jong Soon,Kim, Youngsoo,Han, Sang-Bae Informa UK Ltd. 2014 Journal of enzyme inhibition and medicinal chemist Vol.29 No.5

<P>Since the first histone deacetylase (HDAC) inhibitor (Zolinza®, widely known as suberoylanilide hydroxamic acid; SAHA) was approved by the Food and Drug Administration for the treatment of T-cell lymphoma in 2006, the search for newer HDAC inhibitors has attracted a great deal of interest of medicinal chemists worldwide. As a continuity of our ongoing research in this area, we designed and synthesized a series of 5-substitutedphenyl-1,3,4-thiadiazole-based hydroxamic acids as analogues of SAHA and evaluated their biological activities. A number of compounds in this series, for example, <I>N<SUP>1</SUP></I>-hydroxy-<I>N</I><SUP>8</SUP>-(5-(2-chlorophenyl)-1,3,4-thiadiazol-2-yl)octandiamide (<B>5b</B>), <I>N<SUP>1</SUP></I>-hydroxy-<I>N</I><SUP>8</SUP>-(5-(3-chlorophenyl-1,3,4-thiadiazol-2-yl)octandiamide (<B>5c</B>) and <I>N<SUP>1</SUP></I>-hydroxy-<I>N</I><SUP>8</SUP>-(5-(4-chlorophenyl)-1,3,4-thiadiazol-2-yl)octandiamide (<B>5d</B>), were found to possess potent anticancer cytotoxicity and HDAC inhibition effects. Compounds <B>5b</B>-<B>d</B> were generally two- to five-fold more potent in terms of cytotoxicity compared to SAHA against five cancer cell lines tested. Docking studies revealed that these hydroxamic acid displayed higher affinities than SAHA toward HDAC8.</P>