Author Report for: Lee HSNo contact information in database for Lee HS
Kang MS, Park JH, Lee HS Ref: Exp Appl Acarol, :, 2022 : PubMed ESTHER: Kang_2022_Exp.Appl.Acarol__ PubMedSearch: Kang 2022 Exp.Appl.Acarol PubMedID: 35024988 Abstract Acaricidal activities and acetylcholinesterase (AChE) inhibitory activities were evaluated of active constituents of the essential oil extracted from Alpinia galanga rhizomes cultivated from India and their derivatives against Haemaphysalis longicornis nymphs. In addition, the effect was investigated of active components of A. galanga oil on egg laying of adult females of H. longicornis and egg hatchability. Of the volatile components identified in A. galanga oil, ethyl cinnamate, ethyl methoxycinnamate, and methyl cinnamate at 0.32 mg/cm(2) resulted in 100% mortality, respectively, indicating that the acaricidal activity of the A. galanga oil against H. longicornis nymphs could be attributed to these compounds. To evaluate the structure-activity relationship between cinnamate derivatives and their acaricidal activities, allyl cinnamate, benzyl cinnamate, isopropyl cinnamate, isobutyl cinnamate, and isoamyl cinnamate were selected. Among cinnamate derivatives tested, allyl cinnamate exhibited the most potent toxicity (LC(50) = 0.055 mg/cm(2)) against H. longicornis nymphs. The allyl cinnamate was also tested for AChE activity in vivo in H. longicornis nymphs and was found to affect the AChE activity. Allyl cinnamate at 10-50 mg/mL inhibited egg laying of adult females of H. longicornis by 10-43%. Egg hatching was suppressed completely by treatment with allyl cinnamate at 50 mg/mL, whereas allyl cinnamate was minimally toxic against non-target earthworms, Eisenia fetida. These results suggest that allyl cinnamate can be used as an active ingredient for the development of eco-friendly tick acaricides against H. longicornis, a vector for Sever fever with thrombocytopenia syndrome (SFTS) virus. Title: The Effect of Orlistat on Sterol Metabolism in Obese Patients Kwon YJ, Kwon GE, Lee HS, Choi MH, Lee JW Ref: Front Endocrinol (Lausanne), 13:824269, 2022 : PubMed ESTHER: Kwon_2022_Front.Endocrinol.(Lausanne)_13_824269 PubMedSearch: Kwon 2022 Front.Endocrinol.(Lausanne) 13 824269 PubMedID: 35282441 Abstract BACKGROUND: Orlistat, a reversible inhibitor of pancreatic and gastric lipase, is known to have anti-obesity and antioxidant properties. Cholesterol intermediates and metabolites have diverse and important functions in cardiovascular disease. Therefore, we aimed to evaluate the effect of orlistat on sterol metabolism in overweight and obese adults after weight loss during the intervention or weight loss at 12 weeks. METHODS: A total of 51 (27 in the control group and 24 in the experimental group), patients with a BMI of 27 or greater were randomly assigned in a 1:1 ratio to receive either orlistat (120 mg) three times a day plus phentermine hydrochloride (37.5 mg) once daily or a placebo three times a day plus phentermine hydrochloride (37.5 mg) once daily. The primary study outcome was sterol metabolism. RESULTS: The experimental group exhibited significantly decreased metabolic signatures of serum sterols, free cholesterol, sitosterol, 7alpha-hydroxycholesterol (7alpha-OHC), and 7beta-OHC at 12 weeks. The experimental group also exhibited significantly decreased metabolic ratios of sitosterol and 7alpha-OHC to cholesterol at 12 weeks. Regarding changes in sterol signatures from baseline to 6-month follow-up, free cholesterol, plant sterols, and cholesterol precursors tended to decrease with weight loss during the intervention and increase again as the weight was regained in both groups. CONCLUSION: Orlistat treatment improves oxysterol metabolism in overweight and obese adults. Our findings support that orlistat plays a crucial role in the process of endothelial dysfunction and atherosclerosis via oxysterol modulation. Title: Standardized Extract (HemoHIM) Protects against Scopolamine-Induced Amnesia in a Murine Model Kim SK, Kwon DA, Kim YS, Lee HS, Kim HK, Kim WK Ref: Evid Based Complement Alternat Med, 2021:8884243, 2021 : PubMed ESTHER: Kim_2021_Evid.Based.Complement.Alternat.Med_2021_8884243 PubMedSearch: Kim 2021 Evid.Based.Complement.Alternat.Med 2021 8884243 PubMedID: 33815562 Abstract HemoHIM is a medicinal herbal preparation of Angelica gigas Nakai (Apiaceae), Cnidium officinale Makino (Umbelliferae), and Paeonia lactiflora Pallas (Paeoniaceae) designed for immune regulation. In the present study, the memory-enhancing effects of a standardized extract (HemoHIM) on scopolamine-induced memory impairment in a murine model was investigated. To induce amnesia, scopolamine (1 mg/kg) was intraperitoneally (i.p.) injected into mice 30 min before the start of behavioral tests. The Y-maze, novel object recognition test (NORT), and passive avoidance task (PAT) were used to evoke memory functions. HemoHIM significantly improved scopolamine-induced memory impairment in ICR mice, which was evidenced by an improvement of spontaneous alternation in the Y-maze, recognition index in NORT, and latency time in PAT. To elucidate the possible mechanism, the cholinergic activity and mRNA levels of choline acetyltransferase (ChAT), muscarinic acetylcholine receptor (mAchR), brain-derived neurotrophic factor (BDNF), and cAMP response element-binding protein (CREB) were measured using reverse transcription (RT-PCR) and western blot analyses, respectively. HemoHIM treatment attenuated the scopolamine-induced hyperactivation of acetylcholinesterase (AchE) activity. In addition, ChAT, mAchR, and CREB mRNA levels were increased in the hippocampus compared with the scopolamine group. Furthermore, HemoHIM treatment resulted in elevated BDNF protein expression. These results indicate that HemoHIM may exert antiamnesic activity by increasing Ach and inhibiting AchE in the hippocampus. In addition, HemoHIM has therapeutic potential by upregulating ChAT, mAchR, and BDNF, which is apparently mediated by activation of the CREB and ERK signaling pathways. Title: Chemo-Biological Upcycling of Poly(ethylene terephthalate) to Multifunctional Coating Materials Kim HT, Ryu MH, Jung YJ, Lim S, Song HM, Park J, Hwang SY, Lee HS, Yeon YJ and Oh DX <4 more author(s)> Kim HT, Ryu MH, Jung YJ, Lim S, Song HM, Park J, Hwang SY, Lee HS, Yeon YJ, Sung BH, Bornscheuer UT, Park SJ, Joo JC, Oh DX (- 4) Ref: ChemSusChem, :, 2021 : PubMed ESTHER: Kim_2021_ChemSusChem__ PubMedSearch: Kim 2021 ChemSusChem PubMedID: 34339110 Abstract Chemo-biological upcycling of poly(ethylene terephthalate) (PET) developed in this study includes the following key steps: chemo-enzymatic PET depolymerization, biotransformation of terephthalic acid (TPA) into catechol, and its application as a coating agent. Monomeric units were first produced through PET glycolysis into bis(2-hydroxyethyl) terephthalate (BHET), mono(2-hydroxyethyl) terephthalate (MHET), and PET oligomers and enzymatic hydrolysis of these glycolyzed products using Bacillus subtilis esterase (Bs2Est). Bs2Est efficiently hydrolyzed glycolyzed products into TPA as a key enzyme for chemo-enzymatic depolymerization. Furthermore, catechol solution produced from TPA via a whole-cell biotransformation (Escherichia coli) could be directly used for functional coating on various substrates just after simple cell removal from the culture medium without further purification and water-evaporation. This work demonstrates a proof-of-concept of a PET upcycling strategy via a combination of chemo-biological conversion of PET waste into multifunctional coating materials. Title: Identification of Catalposide Metabolites in Human Liver and Intestinal Preparations and Characterization of the Relevant Sulfotransferase, UDP-glucuronosyltransferase, and Carboxylesterase Enzymes Hwang DK, Kim JH, Shin Y, Choi WG, Kim S, Cho YY, Lee JY, Kang HC, Lee HS Ref: Pharmaceutics, 11:, 2019 : PubMed ESTHER: Hwang_2019_Pharmaceutics_11_ PubMedSearch: Hwang 2019 Pharmaceutics 11 PubMedID: 31336576 Abstract Catalposide, an active component of Veronica species such as Catalpa ovata and Pseudolysimachion lingifolium, exhibits anti-inflammatory, antinociceptic, anti-oxidant, hepatoprotective, and cytostatic activities. We characterized the in vitro metabolic pathways of catalposide to predict its pharmacokinetics. Catalposide was metabolized to catalposide sulfate (M1), 4-hydroxybenzoic acid (M2), 4-hydroxybenzoic acid glucuronide (M3), and catalposide glucuronide (M4) by human hepatocytes, liver S9 fractions, and intestinal microsomes. M1 formation from catalposide was catalyzed by sulfotransferases (SULTs) 1C4, SULT1A1*1, SULT1A1*2, and SULT1E1. Catalposide glucuronidation to M4 was catalyzed by gastrointestine-specific UDP-glucuronosyltransferases (UGTs) 1A8 and UGT1A10; M4 was not detected after incubation of catalposide with human liver preparations. Hydrolysis of catalposide to M2 was catalyzed by carboxylesterases (CESs) 1 and 2, and M2 was further metabolized to M3 by UGT1A6 and UGT1A9 enzymes. Catalposide was also metabolized in extrahepatic tissues; genetic polymorphisms of the carboxylesterase (CES), UDP-glucuronosyltransferase (UGT), and sulfotransferase (SULT) enzymes responsible for catalposide metabolism may cause inter-individual variability in terms of catalposide pharmacokinetics. Title: Identification of metabolic pathways related to the bisphenol A-induced adipogenesis in differentiated murine adipocytes by using RNA-sequencing Lee HS, Park Y Ref: Environ Research, 171:161, 2019 : PubMed ESTHER: Lee_2019_Environ.Res_171_161 PubMedSearch: Lee 2019 Environ.Res 171 161 PubMedID: 30665118 Abstract We evaluated the effect of bisphenol A and its metabolites on the 3T3-L1 cells, in terms of glucose and lipid metabolism. We also aimed to obtain the information on the genome-wide expression changes in the 3T3-L1 cells treated with Bisphenol A by using RNA-seq, which involves whole-transcriptome sequencing. Differentially Expressed Genes (DEGs) collected from RNA-seq can be used to produce a complete picture of related metabolism pathways. The KEGG pathway was extracted based on the DEGs. Bisphenol A significantly increased the mRNA level of Sterol regulatory element binding transcription factor 1 (Srebf1) and CCAAT/enhancer binding protein alpha (Cebpa). Lipoprotein lipase (Lpl) was also significantly influenced by bisphenol A and its metabolites. Acetyl-Coenzyme A carboxylase beta (Acacb) and Fatty acid synthase (Fasn) mRNA levels were elevated by bisphenol A and its metabolites. The insulin signaling pathway, neurotrophin signaling pathway, and endometrial cancer-related pathway were focused by the functional enrichment analyses, and the pathways were well coincided with recent previous reports. DEGs collected from RNA-seq were confirmed as a reliable evidence in the exposure to the chemicals such as bisphenol A. Collecting pieces of the puzzles obtained from the RNA-seq will help us to produce a complete picture of the metabolic pathway for such chemicals. Title: Dipeptidyl-peptidase-4 (DPP-4) inhibitor ameliorates 5-flurouracil induced intestinal mucositis Lee JM, Yoo IK, Kim SH, Choi HS, Kim ES, Keum B, Seo YS, Jeen YT, Chun HJ and Kim CD <2 more author(s)> Lee JM, Yoo IK, Kim SH, Choi HS, Kim ES, Keum B, Seo YS, Jeen YT, Chun HJ, Lee HS, Um SH, Kim CD (- 2) Ref: BMC Cancer, 19:1016, 2019 : PubMed ESTHER: Lee_2019_BMC.Cancer_19_1016 PubMedSearch: Lee 2019 BMC.Cancer 19 1016 PubMedID: 31664952 Abstract BACKGROUND: Chemotherapy-induced alimentary mucositis (AM) is difficult to prevent and treatment is rarely effective. Recent study have been showed that glucagon-like peptide (GLP)-1 and GLP-2 has protective in chemotherapy-induced AM. While the DPP-4 enzyme degrades this GLP-1, the DPP-4 inhibitor blocks the degradation process and raises the concentration of GLP-1. This study aimed to assess the role of DPP-4 inhibitor, a well-known hypoglycemic agent, on chemotherapy-induced AM. METHODS: Twenty-four 6-week-old male C57BL/6 mice were divided into 4 groups: control, 5-fluorouracil (5-FU), DPP-4 inhibitor, and saline (DPP-4i), and DPP-4 inhibitor and 5-FU (DPP-4i + 5-FU). Mucositis was induced by intraperitoneal injection of 5-FU (400 mg/kg). DPP-4 inhibitor (50 mg/kg) was administered orally for four days starting the day before 5-FU administration. Post 72 h of 5-FU injection, mice were sacrificed and body weight change, diarrhea score, villus height, villus/crypt ratio, histologic characteristics including goblet cell count, and mRNA expression of inflammatory cytokines tumor necrosis factor (TNF)-alpha and interleukin (IL)-6, were assessed. RESULTS: Daily body weight change was not statistically significant between the 5-FU and the DPP-4i + 5-FU group (P = 0.571). Diarrhea score was significantly different between these two groups (P = 0.033). In the 5-FU group, the villus height was not maintained well, the epithelial lining was irregular, and inflammatory cell infiltration was observed. Goblet cell count in the DPP-4i + 5-FU group was significantly higher than in the 5-FU group (P = 0.007). However, in the DPP-4i + 5-FU group, the villus height, epithelial lining, and crypt structure were better maintained than in the 5-FU group. Compared with the control group, mRNA expression of TNF-alpha was significantly up-regulated in the 5-FU group. Moreover, mRNA expression of TNF-alpha in the DPP-4i + 5-FU group was down-regulated compared to the 5-FU group. However, IL-6 in the 5-FU group was significantly down-regulated compared to the control, there was no significant difference in expression of IL-6 between the 5-FU and DPP4i + 5-FU group. CONCLUSION: DPP-4 inhibitor can improve 5-FU induced AM and, therefore, has potential as an alternative treatment for chemotherapy-induced AM. Title: Combined toxicity of endosulfan and phenanthrene mixtures and induced molecular changes in adult Zebrafish (Danio rerio) Kim K, Jeon HJ, Choi SD, Tsang DCW, Oleszczuk P, Ok YS, Lee HS, Lee SE Ref: Chemosphere, 194:30, 2017 : PubMed ESTHER: Kim_2017_Chemosphere_194_30 PubMedSearch: Kim 2017 Chemosphere 194 30 PubMedID: 29197246 Abstract Individual and combined toxicities of endosulfan (ENDO) with phenanthrene (PHE) were evaluated using zebrafish (Danio rerio) adults. The 96-h LC50 values for ENDO and PHE were 4.6 mug L(-1) and 920 mug L(-1), respectively. To evaluate the mixture toxicity, LC10 and LC50 concentrations were grouped into four combinations as ENDO-LC10 + PHE-LC10, ENDO-LC10 + PHE-LC50, ENDO-LC50 + PHE-LC10, and ENDO-LC50 + PHE-LC50, and their acute toxicities were determined. The combination of LC50-ENDO and LC10-PHE exhibited a synergistic effect. In addition, acetylcholinesterase activity decreased in zebrafish bodies exposed to ENDO with or without PHE. Combined treatments induced higher glutathione S-transferase activity compared to individual treatments. Carboxylesterase activity increased in both heads and bodies of ENDO-treated fishes compared with PHE-treated fishes. Using RT-qPCR technique, CYP1A gene expression significantly up-regulated in all combinations, whereas CYP3A was unchanged, suggesting that enzymes involved in defense may play different roles in the detoxification. CYP7A1 gene responsible for bile acid biosynthesis is dramatically down-regulated after exposure to the synergistic combination exposure, referring that the synergistic effect may be resulted from the reduction of bile production in zebrafishes. Among gender-related genes, CYP11A1 and CYP17A1 genes in female zebrafish decreased after treatment with ENDO alone and combination of LC50-ENDO and LC10-PHE. This might be related to a reduction in cortisol production. The overall results indicated that ENDO and PHE were toxic to zebrafish adults both individually and in combination, and that their co-presence induced changes in the expression of genes responsible for metabolic processes and defense mechanisms. Title: A novel family VIII carboxylesterase hydrolysing third- and fourth-generation cephalosporins Jeon JH, Lee HS, Lee JH, Koo BS, Lee CM, Lee SH, Kang SG Ref: Springerplus, 5:525, 2016 : PubMed ESTHER: Jeon_2016_Springerplus_5_525 PubMedSearch: Jeon 2016 Springerplus 5 525 PubMedID: 27186489 Abstract A metagenomic library was constructed from a soil sample of spindle tree-rhizosphere. From this library, one clone with esterase activity was selected. The sequence analysis revealed an open reading frame (EstSTR1) encoded protein of 390 amino acids. EstSTR1 is a family VIII carboxylesterase and retains the S-X-X-K motif conserved in both family VIII carboxylesterases and class C beta-lactamases. The estSTR1 gene was overexpressed in E. coli and the recombinant protein was purified by purified by metal chelating affinity chromatography and size-exclusion chromatography. EstSTR1 hydrolysed p-nitrophenyl esters, exhibited the highest activity toward p-nitrophenyl butyrate. Furthermore, EstSTR1 could hydrolyse third- and fourth-generation cephalosporins (cefotaxime and cefepime) as well as first-generation cephalosporin (cephalothin). Site-directed mutagenesis studies revealed that a catalytic residue, Ser71, of EstSTR1 plays an essential role in hydrolysing both antibiotics and p-nitrophenyl esters. We demonstrate that a metagenome-derived carboxylesterase displays beta-lactam-hydrolysing activities toward third- and fourth-generation cephalosporins. Title: Multifunctional Activity of Polyphenolic Compounds Associated with a Potential for Alzheimer's Disease Therapy from Ecklonia cava Choi BW, Lee HS, Shin HC, Lee BH Ref: Phytother Res, 29:549, 2015 : PubMed ESTHER: Choi_2015_Phytother.Res_29_549 PubMedSearch: Choi 2015 Phytother.Res 29 549 PubMedID: 25640212 Abstract Five polyphenols were isolated and purified from a brown alga Ecklonia cava. These compounds showed diverse biological activities such as antioxidative, antiinflammatory, and enzyme inhibitory activities. This led us to investigate the potential of these compounds as Alzheimer's disease drugs. All of the compounds showed moderate acetylcholinesterase inhibitory activity in a micromolar range (IC50 from 16.0 to 96.3 muM). For butyrylcholinesterase, a new target for the treatment of Alzheimer's disease, phlorofucofuroeckol-A (PFF-A), showed a particularly potent inhibitory activity (IC50 0.95 muM), which is over 100-fold greater than for acetylcholinesterase. These compounds inhibited glycogen synthase kinase 3 beta, which is related to the formation of hyperphosphorylated tau and generation Abeta. Bieckol and PFF-A inhibited amyloid precursor protein biosynthesis. PFF-A also showed very strong beta-secretase inhibitory activity with IC50 of submicromole. These results render these compounds as interesting potential drug candidates for Alzheimer's disease. Copyright (c) 2015 John Wiley & Sons, Ltd. Title: In Vitro Metabolic Pathways of the New Anti-Diabetic Drug Evogliptin in Human Liver Preparations Jeong HU, Kim JH, Lee DY, Shim HJ, Lee HS Ref: Molecules, 20:21802, 2015 : PubMed ESTHER: Jeong_2015_Molecules_20_21802 PubMedSearch: Jeong 2015 Molecules 20 21802 PubMedID: 26690104 Inhibitor(s) related to this paper: Evogliptin Abstract Evogliptin ((R)-4-((R)-3-amino-4-(2,4,5-trifluorophenyl)butanoyl)-3-(tert-butoxymethyl)-pipe razin-2-one), is a new dipeptidyl peptidase IV inhibitor used for the treatment of type II diabetes mellitus. The in vitro metabolic pathways of evogliptin were identified in human hepatocytes, liver microsomes, and liver S9 fractions using liquid chromatography-Orbitrap mass spectrometry (LC-HRMS). Five metabolites of evogliptin-4-oxoevogliptin (M1), 4(S)-hydroxyevogliptin (M2), 4(R)-hydroxyevogliptin (M3), 4(S)-hydroxyevogliptin glucuronide (M4), and evogliptin N-sulfate (M5)-were identified in human liver preparations by comparison with authentic standards. We characterized the cytochrome P450 (CYP) enzymes responsible for evogliptin hydroxylation to 4(S)-hydroxyevogliptin (M2) and 4(R)-hydroxyevogliptin (M3) and the UGT enzymes responsible for glucuronidation of 4(S)-hydroxyevogliptin (M2) to 4(S)-hydroxy-evogliptin glucuronide (M4). CYP3A4/5 played the major role in the hydroxylation of evogliptin to 4(S)-hydroxyevogliptin (M2) and 4(R)-hydroxyevogliptin (M3). Glucuronidation of 4(S)-hydroxy-evogliptin (M2) to 4(S)-hydroxyevogliptin glucuronide (M4) was catalyzed by the enzymes UGT2B4 and UGT2B7. These results suggest that the interindividual variability in the metabolism of evogliptin in humans is a result of the genetic polymorphism of the CYP and UGT enzymes responsible for evogliptin metabolism. Title: Structural basis for the beta-lactamase activity of EstU1, a family VIII carboxylesterase Cha SS, An YJ, Jeong CS, Kim MK, Jeon JH, Lee CM, Lee HS, Kang SG, Lee JH Ref: Proteins, 81:2045, 2013 : PubMed ESTHER: Cha_2013_Proteins_81_2045 PubMedSearch: Cha 2013 Proteins 81 2045 PubMedID: 23737193 Abstract EstU1 is a unique family VIII carboxylesterase that displays hydrolytic activity toward the amide bond of clinically used beta-lactam antibiotics as well as the ester bond of p-nitrophenyl esters. EstU1 assumes a beta-lactamase-like modular architecture and contains the residues Ser100, Lys103, and Tyr218, which correspond to the three catalytic residues (Ser64, Lys67, and Tyr150, respectively) of class C beta-lactamases. The structure of the EstU1/cephalothin complex demonstrates that the active site of EstU1 is not ideally tailored to perform an efficient deacylation reaction during the hydrolysis of beta-lactam antibiotics. This result explains the weak beta-lactamase activity of EstU1 compared with class C beta-lactamases. Finally, structural and sequential comparison of EstU1 with other family VIII carboxylesterases elucidates an operative molecular strategy used by family VIII carboxylesterases to extend their substrate spectrum. Proteins 2013; 81:2045-2051. (c) 2013 Wiley Periodicals, Inc. Title: Endogenous ACh tonically stimulates ANP secretion in rat atria Kim HY, Cho KW, Xu DY, Kang DG, Lee HS Ref: American Journal of Physiology Heart Circ Physiol, 305:H1050, 2013 : PubMed ESTHER: Kim_2013_Am.J.Physiol.Heart.Circ.Physiol_305_H1050 PubMedSearch: Kim 2013 Am.J.Physiol.Heart.Circ.Physiol 305 H1050 PubMedID: 23913708 Inhibitor(s) related to this paper: Methoctramine Abstract Exogenous acetylcholine (ACh) is known to stimulate atrial natriuretic peptide (ANP) secretion concomitantly with a decrease in atrial pulse pressure. However, the role of intrinsic ACh in the regulation of ANP secretion remains unknown. Recently, it was shown that nonneuronal and neuronal ACh is present in the cardiac atria. From this finding we hypothesize that endogenously released ACh is involved in the regulation of ANP secretion in an autocrine or paracrine manner in the atria. Experiments were performed in isolated beating rat atria. ANP was measured using radioimmunoassay. To increase the availability of the ACh in the extracellular space of the atrium, its degradation was inhibited with an inhibitor of acetylcholinesterase. Acetylcholinesterase inhibition with physostigmine increased ANP secretion concomitantly with a decrease in atrial dynamics in a concentration-dependent manner. Inhibitors of M2 muscarinic ACh receptor (mAChR), methoctramine, and ACh-activated K(+) (KACh(+)) channels, tertiapin-Q, abolished the physostigmine-induced changes. The effects were not observed in the atria from rats treated with pertussis toxin. Furthermore, the physostigmine-induced effects were attenuated by an inhibitor of high-affinity choline transporter, hemicholinium-3, which is a rate-limiting step of ACh synthesis. Inhibitors of the mAChR signaling pathway and ACh synthesis also attenuated the basal levels of ANP secretion and accentuated atrial dynamics. These findings suggest that endogenously released ACh tonically stimulates ANP secretion from atrial cardiomyocytes via activation of M2 mAChR-Gi/o-KACh(+) channel signaling. It is also suggested that the ACh-ANP signaling is implicated in cardiac physiology and pathophysiology. Title: Identification of a new subfamily of salt-tolerant esterases from a metagenomic library of tidal flat sediment Jeon JH, Lee HS, Kim JT, Kim SJ, Choi SH, Kang SG, Lee JH Ref: Applied Microbiology & Biotechnology, 93:623, 2012 : PubMed ESTHER: Jeon_2012_Appl.Microbiol.Biotechnol_93_623 PubMedSearch: Jeon 2012 Appl.Microbiol.Biotechnol 93 623 PubMedID: 21720822 Gene_locus related to this paper: 9bact-E40, 9bact-E25, 9bact-d8v1j5, 9bact-d8v1j4, 9bact-d8v1j3 Abstract To search for novel lipolytic enzymes, a metagenomic library was constructed from the tidal flat sediment of Ganghwa Island in South Korea. By functional screening using tributyrin agar plates, 3 clones were selected from among the 80,050 clones of the fosmid library. The sequence analysis revealed that those clones contained different open reading frames, which showed 50-57% amino acid identity with putative lipolytic enzymes in the database. Based on the phylogenetic analysis, they were identified to encode novel members, which form a distinct and new subfamily in the family IV of bacterial lipolytic enzymes. The consensus sequence, GT(S)SA(G)G, encompassing the active site serine of the enzymes was different from the GDSAG motif, conserved in the other subfamily. The genes were expressed in Escherichia coli and recombinant proteins were purified as active soluble forms. The enzymes showed the highest activity toward p-nitrophenyl valerate (C5) and exhibited optimum activities at mesophilic temperature ranges and slightly alkaline pH. In particular, the enzymes displayed salt tolerance with over 50% of the maximum activity remained in the presence of 3 M NaCl (or KCl). In this study, we demonstrated that the metagenomic approach using marine tidal flat sediment as a DNA source expanded the diversity of lipolytic enzyme-encoding genes. Title: Novel lipolytic enzymes identified from metagenomic library of deep-sea sediment Jeon JH, Kim JT, Lee HS, Kim SJ, Kang SG, Choi SH, Lee JH Ref: Evid Based Complement Alternat Med, 2011:271419, 2011 : PubMed ESTHER: Jeon_2011_Evid.Based.Complement.Alternat.Med_2011_271419 PubMedSearch: Jeon 2011 Evid.Based.Complement.Alternat.Med 2011 271419 PubMedID: 21845199 Gene_locus related to this paper: 9bact-d8v1j0, 9bact-d8v1i9, 9bact-d8v1i5, 9bact-d8v1i8, 9bact-d8v1i6, 9bact-d8v1i7 Abstract Metagenomic library was constructed from a deep-sea sediment sample and screened for lipolytic activity. Open-reading frames of six positive clones showed only 33-58% amino acid identities to the known proteins. One of them was assigned to a new group while others were grouped into Families I and V or EstD Family. By employing a combination of approaches such as removing the signal sequence, coexpression of chaperone genes, and low temperature induction, we obtained five soluble recombinant proteins in Escherichia coli. The purified enzymes had optimum temperatures of 30-35 degrees C and the cold-activity property. Among them, one enzyme showed lipase activity by preferentially hydrolyzing p-nitrophenyl palmitate and p-nitrophenyl stearate and high salt resistance with up to 4 M NaCl. Our research demonstrates the feasibility of developing novel lipolytic enzymes from marine environments by the combination of functional metagenomic approach and protein expression technology. Title: Novel metagenome-derived carboxylesterase that hydrolyzes beta-lactam antibiotics Jeon JH, Kim SJ, Lee HS, Cha SS, Lee JH, Yoon SH, Koo BS, Lee CM, Choi SH and Kang SG <1 more author(s)> Jeon JH, Kim SJ, Lee HS, Cha SS, Lee JH, Yoon SH, Koo BS, Lee CM, Choi SH, Lee SH, Kang SG (- 1) Ref: Applied Environmental Microbiology, 77:7830, 2011 : PubMed ESTHER: Jeon_2011_Appl.Environ.Microbiol_77_7830 PubMedSearch: Jeon 2011 Appl.Environ.Microbiol 77 7830 PubMedID: 21908637 Abstract It has been proposed that family VIII carboxylesterases and class C beta-lactamases are phylogenetically related; however, none of carboxylesterases has been reported to hydrolyze beta-lactam antibiotics except nitrocefin, a nonclinical chromogenic substrate. Here, we describe the first example of a novel carboxylesterase derived from a metagenome that is able to cleave the amide bond of various beta-lactam substrates and the ester bond of p-nitrophenyl esters. A clone with lipolytic activity was selected by functional screening of a metagenomic library using tributyrin agar plates. The sequence analysis of the clone revealed the presence of an open reading frame (estU1) encoding a polypeptide of 426 amino acids, retaining an S-X-X-K motif that is conserved in class C beta-lactamases and family VIII carboxylesterases. The gene was overexpressed in Escherichia coli, and the purified recombinant protein (EstU1) was further characterized. EstU1 showed esterase activity toward various chromogenic p-nitrophenyl esters. In addition, it exhibited hydrolytic activity toward nitrocefin, leading us to investigate whether EstU1 could hydrolyze beta-lactam antibiotics. EstU1 was able to hydrolyze first-generation beta-lactam antibiotics, such as cephalosporins, cephaloridine, cephalothin, and cefazolin. In a kinetic study, EstU1 showed a similar range of substrate affinities for both p-nitrophenyl butyrate and first-generation cephalosporins while the turnover efficiency for the latter was much lower. Furthermore, site-directed mutagenesis studies revealed that the catalytic triad of EstU1 plays a crucial role in hydrolyzing both ester bonds of p-nitrophenyl esters and amide bonds of the beta-lactam ring of antibiotics, implicating the predicted catalytic triad of EstU1 in both activities. Title: Genome sequence of the algicidal bacterium Kordia algicida OT-1 Lee HS, Kang SG, Kwon KK, Lee JH, Kim SJ Ref: Journal of Bacteriology, 193:4031, 2011 : PubMed ESTHER: Lee_2011_J.Bacteriol_193_4031 PubMedSearch: Lee 2011 J.Bacteriol 193 4031 PubMedID: 21622754 Gene_locus related to this paper: 9flao-a9dk52 Abstract Kordia algicida OT-1 is an algicidal bacterium against the bloom-forming microalgae. The genome sequence of K. algicida revealed a number of interesting features, including the degradation of macromolecules, the biosynthesis of carotenoid pigment and secondary metabolites, and the capacity for gliding motility, which might facilitate the understanding of algicidal mechanisms. Title: Enantioselective hydrolysis of racemic epichlorohydrin using an epoxide hydrolase from Novosphingobium aromaticivorans Woo JH, Hwang YO, Kang JH, Lee HS, Kim SJ, Kang SG Ref: J Biosci Bioeng, 110:295, 2010 : PubMed ESTHER: Woo_2010_J.Biosci.Bioeng_110_295 PubMedSearch: Woo 2010 J.Biosci.Bioeng 110 295 PubMedID: 20547378 Gene_locus related to this paper: novad-q2g620 Abstract Previously we reported that an epoxide hydrolase (EHase) from Novosphingobium aromaticivorans could preferentially hydrolyze (R)-styrene oxide. In this study, we demonstrate that the purified NEH could be also effective in chiral resolution of racemic epichlorohydrin (ECH). Particularly, the purified NEH showed excellent hydrolyzing activity toward ECH to complete the reaction at a short period of incubation time. Enantiopure (S)-ECH could be obtained with a high enantiopurity of more than 99.99% enantiomeric excess (ee) and yield of 20.7% (theoretical, 50%). The chiral resolution of the purified NEH toward ECH was not susceptible to substrate inhibition by 500 mM racemic ECH. Title: Cloning and characterization of a new cold-active lipase from a deep-sea sediment metagenome Jeon JH, Kim JT, Kim YJ, Kim HK, Lee HS, Kang SG, Kim SJ, Lee JH Ref: Applied Microbiology & Biotechnology, 81:865, 2009 : PubMed ESTHER: Jeon_2009_Appl.Microbiol.Biotechnol_81_865 PubMedSearch: Jeon 2009 Appl.Microbiol.Biotechnol 81 865 PubMedID: 18773201 Gene_locus related to this paper: 9bact-a0ejl0 Abstract To search for new cold-active lipases, a metagenomic library was constructed using cold-sea sediment samples at Edison Seamount and was screened for lipolytic activities by plating on a tricaprylin medium. Subsequently, a fosmid clone was selected, and the whole sequence of 36 kb insert of the fosmid clone was determined by shotgun sequencing. The sequence analysis revealed the presence of 25 open reading frames (ORF), and ORF20 (EML1) showed similarities to lipases. Phylogenetic analysis of EML1 suggested that the protein belonged to a new family of esterase/lipase together with LipG. The EML1 gene was expressed in Escherichia coli, and purified by metal-chelating chromatography. The optimum activity of the purified EML1 (rEML1) occurred at pH 8.0 and 25 degrees C, respectively, and rEML1 displayed more than 50% activity at 5 degrees C. The activation energy for the hydrolysis of olive oil was determined to be 3.28 kcal/mol, indicating that EML1 is a cold-active lipase. rEML1 preferentially hydrolyzed triacylglycerols acyl-group chains with long chain lengths of > or = 8 carbon atoms and displayed hydrolyzing activities toward various natural oil substrates. rEML1 was resistant to various detergents such as Triton X-100 and Tween 80. This study represents an example which developed a new cold-active lipase from a deep-sea sediment metagenome. Title: The cmaR gene of Corynebacterium ammoniagenes performs a novel regulatory role in the metabolism of sulfur-containing amino acids Lee SM, Hwang BJ, Kim Y, Lee HS Ref: Microbiology, 155:1878, 2009 : PubMed ESTHER: Lee_2009_Microbiology_155_1878 PubMedSearch: Lee 2009 Microbiology 155 1878 PubMedID: 19383689 Abstract A novel regulatory gene, which performs an essential function in sulfur metabolism, has been identified in Corynebacterium ammoniagenes and was designated cmaR (cysteine and methionine regulator in C. ammoniagenes). The cmaR-disrupted strain (DeltacmaR) lost the ability to grow on minimal medium, and was identified as a methionine and cysteine double auxotroph. The mutant strain proved unable to convert cysteine to methionine (and vice versa), and lost the ability to assimilate and reduce sulfate to sulfide. In the DeltacmaR strain, the mRNAs of the methionine biosynthetic genes metYX, metB and metFE were significantly reduced, and the activities of the methionine biosynthetic enzymes cystathionine gamma-synthase, O-acetylhomoserine sulfhydrylase, and cystathionine beta-lyase were relatively low, thereby suggesting that the cmaR gene exerts a positive regulatory effect on methionine biosynthetic genes. In addition, with the exception of cysK, reduced transcription levels of the sulfur-assimilatory genes cysIXYZ and cysHDN were noted in the cmaR-disrupted strain, which suggests that sulfur assimilation is also under the positive control of the cmaR gene. Furthermore, the expression of the cmaR gene itself was strongly induced via the addition of cysteine or methionine alone, but not the introduction of both amino acids together to the growth medium. In addition, the expression of the cmaR gene was enhanced in an mcbR-disrupted strain, which suggests that cmaR is under the negative control of McbR, which has been identified as a global regulator of sulfur metabolism. DNA binding of the purified CmaR protein to the promoter region of its target genes could be demonstrated in vitro. No metabolite effector was required for the protein to bind DNA. These results demonstrated that the cmaR gene of C. ammoniagenes plays a role similar to but distinct from that of the functional homologue cysR of Corynebacterium glutamicum. Title: The complete genome sequence of Thermococcus onnurineus NA1 reveals a mixed heterotrophic and carboxydotrophic metabolism Lee HS, Kang SG, Bae SS, Lim JK, Cho Y, Kim YJ, Jeon JH, Cha SS, Kwon KK and Lee JH <7 more author(s)> Lee HS, Kang SG, Bae SS, Lim JK, Cho Y, Kim YJ, Jeon JH, Cha SS, Kwon KK, Kim HT, Park CJ, Lee HW, Kim SI, Chun J, Colwell RR, Kim SJ, Lee JH (- 7) Ref: Journal of Bacteriology, 190:7491, 2008 : PubMed ESTHER: Lee_2008_J.Bacteriol_190_7491 PubMedSearch: Lee 2008 J.Bacteriol 190 7491 PubMedID: 18790866 Gene_locus related to this paper: theon-b6ywd5 Abstract Members of the genus Thermococcus, sulfur-reducing hyperthermophilic archaea, are ubiquitously present in various deep-sea hydrothermal vent systems and are considered to play a significant role in the microbial consortia. We present the complete genome sequence and feature analysis of Thermococcus onnurineus NA1 isolated from a deep-sea hydrothermal vent area, which reveal clues to its physiology. Based on results of genomic analysis, T. onnurineus NA1 possesses the metabolic pathways for organotrophic growth on peptides, amino acids, or sugars. More interesting was the discovery that the genome encoded unique proteins that are involved in carboxydotrophy to generate energy by oxidation of CO to CO(2), thereby providing a mechanistic basis for growth with CO as a substrate. This lithotrophic feature in combination with carbon fixation via RuBisCO (ribulose 1,5-bisphosphate carboxylase/oxygenase) introduces a new strategy with a complementing energy supply for T. onnurineus NA1 potentially allowing it to cope with nutrient stress in the surrounding of hydrothermal vents, providing the first genomic evidence for the carboxydotrophy in Thermococcus. Title: A quantitative analysis of N-myc downstream regulated gene 2 (NDRG 2) in human tissues and cell lysates by reverse-phase protein microarray Park MY, Choi SC, Lee HS, Kim D, Baek KE, Kim JT, Lim JS, Yeom YI, Chung JW and Song EY <3 more author(s)> Park MY, Choi SC, Lee HS, Kim D, Baek KE, Kim JT, Lim JS, Yeom YI, Chung JW, Kim JW, Myung PK, Lee HG, Song EY (- 3) Ref: Clinica Chimica Acta, 387:84, 2008 : PubMed ESTHER: Park_2008_Clin.Chim.Acta_387_84 PubMedSearch: Park 2008 Clin.Chim.Acta 387 84 PubMedID: 17936257 Abstract BACKGROUND: N-myc downstream regulated gene 2 (NDRG2) belongs to the NDRG family, which is comprised of 4 members, NDRG1-4. Recently, NDRG2 was reported as a new candidate for a tumor suppressor gene. We developed a reverse-phase protein microarray assay to access NDRG2 levels in human tissue specimens and cell lines. METHODS: We synthesized recombinant NDRG2 protein and produced monoclonal antibodies (mAb) to the NDRG2 protein. We selected 2 hybridomas producing mAb that specifically recognize the NDRG2 protein. To determine the NDRG2 concentration, the samples of serially-diluted NDRG2 protein, cell lysate, or tissue lysate were spotted onto a nitrocellulose membrane-coated slide glass and allowed to react with the mAb to the NDRG2 protein. The reaction was followed by additional incubation with biotin-linked anti-mouse IgG and horseradish peroxidase (HRP)-conjugated streptavidin, subsequently. The addition of dimethylaminobenzidine induced color development, which was measured using the GenePix program. We determined the NDRG2 concentration in various tissue specimens and cell lines using the new protein microarray technique. RESULTS: The dose-response relationship between NDRG2 and color intensity showed linearity in a range 0-10 ng/ml and a sensitivity of 50 pg/ml. The NDRG2 concentrations in the liver tissue lysates of patients with hepatocellular carcinoma (52.0+21.5 ng/mg) were significantly diminished as compared with those in the normal liver tissues (549.6+94.6 ng/mg). The results of the assay showed good agreement with those of Western blot analysis. CONCLUSIONS: The protein microarray is a highly sensitive and accurate method, and can adopted to assess specific proteins in human tissues or cell lines, particularly in the field of cancer and pathological research. Title: Cloning and characterization of three epoxide hydrolases from a marine bacterium, Erythrobacter litoralis HTCC2594 Woo JH, Hwang YO, Kang SG, Lee HS, Cho JC, Kim SJ Ref: Applied Microbiology & Biotechnology, 76:365, 2007 : PubMed ESTHER: Woo_2007_Appl.Microbiol.Biotechnol_76_365 PubMedSearch: Woo 2007 Appl.Microbiol.Biotechnol 76 365 PubMedID: 17541582 Abstract Previously, we reported that ten strains belonging to Erythrobacter showed epoxide hydrolase (EHase) activities toward various epoxide substrates. Three genes encoding putative EHases were identified by analyzing open reading frames of Erythrobacter litoralis HTCC2594. Despite low similarities to reported EHases, the phylogenetic analysis of the three genes showed that eeh1 was similar to microsomal EHase, while eeh2 and eeh3 could be grouped with soluble EHases. The three EHase genes were cloned, and the recombinant proteins (rEEH1, rEEH2, and rEEH3) were purified. The functionality of purified proteins was proved by hydrolytic activities toward styrene oxide. EEH1 preferentially hydrolyzed (R)-styrene oxide, whereas EEH3 preferred to hydrolyze (S)-styrene oxide, representing enantioselective hydrolysis of styrene oxide. On the other hand, EEH2 could hydrolyze (R)- and (S)-styrene oxide at an equal rate. The optimal pH and temperature for the EHases occurred largely at neutral pHs and 40-55 degrees C. The substrate selectivity of rEEH1, rEEH2, and rEEH3 toward various epoxide substrates were also investigated. This is the first representation that a strict marine microorganism possessed three EHases with different enantioselectivity toward styrene oxide. Title: Inhibition of dipeptidyl peptidase IV by novel inhibitors with pyrazolidine scaffold Cheon HG, Kim SS, Kim KR, Rhee SD, Yang SD, Ahn JH, Park SD, Lee JM, Jung WH and Kim HY <1 more author(s)> Cheon HG, Kim SS, Kim KR, Rhee SD, Yang SD, Ahn JH, Park SD, Lee JM, Jung WH, Lee HS, Kim HY (- 1) Ref: Biochemical Pharmacology, 70:22, 2005 : PubMed ESTHER: Cheon_2005_Biochem.Pharmacol_70_22 PubMedSearch: Cheon 2005 Biochem.Pharmacol 70 22 PubMedID: 15893294 Abstract Inhibition of dipeptidyl peptidase IV (DPP-IV) activity has been reported to improve nutrient-stimulated insulin secretion through the stabilization of glucagon-like peptide (GLP-1). In the present study, we identified novel DPP-IV inhibitors of pyrazolidine derivatives (Compounds 1 and 2) and characterized their biological effects in vitro and in vivo. Compound 1, an isoleucine pyrazolidide with a phenyl urea group, inhibited rat plasma DPP-IV, porcine kidney DPP-IV, as well as human Caco-2 DPP-IV with IC(50) values of 1.70, 2.26, and 2.02 microM, respectively. Because of the poor pharmacokinetic properties of Compound 1, further optimization was carried out, leading to the discovery of Compound 2, which had similar in vitro activities. Compound 2 acted as a selective and competitive inhibitor of DPP-IV. MALDI-TOF mass spectrometric analysis proved that the compound (20 microM) effectively blocked the degradation of active GLP-1 peptide by 61%. Although similar in in vitro potency, marked improvement of in vivo efficacy and pharmacokinetic properties was seen with Compound 2. Oral administration of Compound 2 resulted in potent and rapid inhibition of circulating DPP-IV in C57BL/6J mice, with ED(50) values of 26mg/kg (s.c.) and 42mg/kg (p.o.). In addition, this compound improved glucose tolerance in ob/ob mice, as determined by an oral glucose tolerance test (OGTT). These results indicate that Compound 2 is a potent and selective DPP-IV inhibitor with oral anti-hyperglycemic activity in vivo. Title: Oxidation of organophosphorus pesticides for the sensitive detection by a cholinesterase-based biosensor Lee HS, Kim YA, Cho YA, Lee YT Ref: Chemosphere, 46:571, 2002 : PubMed ESTHER: Lee_2002_Chemosphere_46_571 PubMedSearch: Lee 2002 Chemosphere 46 571 PubMedID: 11838436 Abstract A potentiometric flow injection-type biosensor developed in our laboratory was used for the determination of organophosphorus pesticides (OPs). The principle of the biosensor is that the degree of inhibition of a sensor enzyme by an OP is dependent on the concentration of the pesticide. The sensor system consisted of a reactor with acetylcholinesterase (AChE) immobilized on a controlled pore glass and a detector with a tubular H(+)-selective membrane electrode. In order to examine the possibility of enhancing the sensitivity of the sensor by converting OPs to oxidized forms (stronger inhibitors), a comparison of the degree of enzyme inhibition by OPs at 10(-6) M before and after their oxidation was made. All of the ten pesticides tested exhibited greater inhibitory power toward the sensor enzyme following oxidation. All of the oxidized pesticides at 10(-6) M inhibited the sensor enzyme to a considerable degree, demonstrating the utility of the developed method for the class-specific determination of OPs. A calibration curve for diazinon, over the concentration range of 10(-11)-10(-4) M, was obtained. The lower detection limit was 2 x 10(-10) M. Treatment of the inhibited enzyme with pyridine-2-aldoxime restored the enzyme to near full activity, allowing repeated use of the sensor. Title: Metabolism of flupyrazofos in the isolated perfused rat liver Jeong CK, Lee H-Y, Kim SB, Choi SJ, Kim J-H, Kim K, Han SS, Lee HS, Lee HY, Kim JH Ref: Pest Manag Sci, 57:427, 2001 : PubMed ESTHER: Jeong_2001_Pest.Manag.Sci_57_427 PubMedSearch: Jeong 2001 Pest.Manag.Sci 57 427 PubMedID: 11374159 Inhibitor(s) related to this paper: Flupyrazofos Abstract To investigate the hepatic metabolism of the new insecticide flupyrazofos [O,O-diethyl O-(1-phenyl-3-trifluoromethylpyrazol-5-yl) phosphorothioate], isolated rat liver was perfused with flupyrazofos under single-pass conditions. In outflow perfusate and bile, 1-phenyl-3-trifluoromethyl-5-hydroxyprazole (PTMHP), PTMHP-sulfate and PTMHP-glucuronide conjugates were identified as the metabolites of flupyrazofos. However, O,O-diethyl O-(1-phenyl-3-trifluoromethylpyrazol-5-yl) phosphate (flupyrazofos oxon) was not detected. A HPLC method with UV detection was used to investigate the hepatic disposition of flupyrazofos and its metabolite PTMHP. The concentrations of flupyrazofos, PTMHP and PTMHP conjugates in outflow perfusate reached steady-state levels within 20 min after commencing perfusion of 7.3 microM flupyrazofos. At steady state, the mean extraction ratio of flupyrazofos was 0.93 (+/- 0.01) and clearance was 26.1 (+/- 0.2) ml min-1 which nearly approached perfusate flow rate (28 ml min-1). PTMHP accounted for 55.7 (+/- 5.8)% of eliminated flupyrazofos and was recovered as unchanged PTMHP, PTMHP-sulfate and PTMHP-glucuronide in the bile as well as the outflow perfusate. Title: A convenient method for oxidation of organophosphorus pesticides in organic solvents Kim YA, Lee HS, Park YC, Lee YT Ref: Environ Research, 84:303, 2000 : PubMed ESTHER: Kim_2000_Environ.Res_84_303 PubMedSearch: Kim 2000 Environ.Res 84 303 PubMedID: 11097804 Abstract Since organophosphorus pesticides can be oxidized to oxons in vivo and in the environment and their determination based on inhibition of cholinesterases can be more sensitive after their oxidation to oxons, development of an efficient method for their in vitro oxidation is important for their toxicological and analytical studies. This study demonstrated that treatment of organophosphorus pesticides with 10 molar excess bromine in acetonitrile is a rapid and efficient method for their oxidation. For the nine organophosphorus pesticides tested, the reaction was complete within a few seconds. All reactions gave the respective oxons as single major product, except that of fenthion, which gave two major products, the respective oxon and another product from further oxidation of the oxon. The yields of the oxons were 82-100%. The inhibitory power of the pesticides on acetylcholinesterase before and after oxidation was measured and, for all pesticides tested, the power after oxidation was much higher than that before oxidation. Inhibition calibration curves for both unoxidized and oxidized forms of fenitrothion and parathion were obtained. The sensitivity of the detection of these pesticides was much higher after oxidation. Title: Effects of flupyrazofos on liver microsomal cytochrome P450 in the male Fischer 344 rat Lee HS, Lee HY, Gu HK, Han SS, Yun CH, Kim JH, Kim JA, Lee ES, Nam DH, Jeong TC Ref: Xenobiotica, 30:1123, 2000 : PubMed ESTHER: Lee_2000_Xenobiotica_30_1123 PubMedSearch: Lee 2000 Xenobiotica 30 1123 PubMedID: 11307969 Abstract 1. The effects of flupyrazofos on liver microsomal cytochrome P450 were investigated in the male Fischer 344 rat. When rats were treated intraperitoneally with flupyrazofos for 3 consecutive days, the activities of ethoxyresorufin O-deethylase and testosterone 2 beta-hydroxylase were significantly reduced, whereas the activities of pentoxyresorufin beta-depentylase and testosterone 6beta- and 7 alpha-hydroxylases were induced in liver microsomes. 2. Within 24 h after treatment with 50 m kg(-1) flupyrazofos, most enzyme activities were decreased, indicating the interaction of flupyrazofos with cytochrome P450. 3. In Western immunoblotting, cytochrome P4502B1/2 proteins were clearly induced by treatment with flupyrazofos, whereas P4501A1/2 and 2C6 proteins were reduced in liver microsomes. 4. The present results indicate that flupyrazofos modulates the expression of cytochrome P450 in rat. Title: Association of CYP1A1 and microsomal epoxide hydrolase polymorphisms with lung squamous cell carcinoma Lin P, Wang SL, Wang HJ, Chen KW, Lee HS, Tsai KJ, Chen CY, Lee H Ref: Br J Cancer, 82:852, 2000 : PubMed ESTHER: Lin_2000_Br.J.Cancer_82_852 PubMedSearch: Lin 2000 Br.J.Cancer 82 852 PubMedID: 10732758 Abstract Lung cancer is the leading cause of death among cancers in Taiwan. Although the etiology of lung cancer has yet to be defined, genetic variability in activities of metabolic enzymes has been correlated with lung cancer. In the present study, the possibility of association of CYP1A1 and microsomal epoxide hydrolase (HYL1) genetic polymorphisms with lung cancer was examined among 132 lung cancer patients and 259 controls in Taiwan. No significant association was observed for either CYP1A1 or HYL1 polymorphism alone and the overall incidence of lung cancer after adjusting for age, gender and smoking status. When cases were stratified according to histological type, there was significant association between CYP1A1*2A homozygote and squamous cell carcinoma (SCC) (odds ratio (OR) 2.86; 95% confidence interval (CI) 1.33-6.12). Similarly, the proportion of HYL1 genotypes corresponding to high or normal enzyme activities was higher in SCC than in controls (OR 1.96; 95% CI 1.04-3.70). A combination of susceptible CYP1A1 and HYL1 genotypes was found to be highly associated with lung cancer, especially with SCC (OR 6.76; 95% CI 2.29-19.10). Our results suggest that the combination of CYP1A1 and HYL1 polymorphisms is an important risk factor for lung SCC. Title: Fabrication of butyrylcholinesterase sensor using polyurethane-based ion-selective membranes Cho YA, Lee HS, Cha GS, Lee YT Ref: Biosensors & Bioelectronics, 14:435, 1999 : PubMed ESTHER: Cho_1999_Biosens.Bioelectron_14_435 PubMedSearch: Cho 1999 Biosens.Bioelectron 14 435 PubMedID: 10422245 Abstract A simple method of enzyme immobilization was investigated which is useful for fabrication of enzyme sensors based on polymeric ion-selective membranes. The enzyme membrane was built by coating a thin hydrophilic polyurethane (HPU) film directly mixed with an enzyme over an underlying polyurethane (PU)-based ion-selective membrane. This highly simple method of enzyme immobilization was applied to the fabrication of a potentiometric butyrylcholinesterase-based biosensor for the determination of organophosphorus pesticides. The enzyme was well entrapped within the HPU film and the intrinsic potentiometric response of the underlying ion-selective PU membrane was not influenced significantly by the outer HPU/enzyme membrane. The enzyme electrode was optimized by changing systematically the composition of the enzyme membrane to evaluate the effect of the changes on sensor response. The sensor was successfully applied to the analysis of paraoxon, an organophosphorus pesticide. Title: Isolation and analysis of metA, a methionine biosynthetic gene encoding homoserine acetyltransferase in corynebacterium glutamicum Park SD, Lee JY, Kim Y, Kim JH, Lee HS Ref: Mol Cells, 8:286, 1998 : PubMed ESTHER: Park_1998_Mol.Cells_8_286 PubMedSearch: Park 1998 Mol.Cells 8 286 PubMedID: 9666465 Gene_locus related to this paper: corgl-metx Abstract The metA gene encoding homoserine acetyltransferase, the first enzyme of the methionine biosynthetic pathway, was isolated from a pMT1-based corynebacterium glutamicum gene library via complementation of an Escherichia coli metA mutant. A DNA-sequence analysis of the cloned DNA is identified an open-reading frame of 1,137 bp which encodes a protein with the molecular weight of 41,380 comprising 379 amino acids. The putative protein product showed good amino acid-sequence homology to its counterpart in other organisms. The internal fragment of the cloned DNA was successfully used to disrupt chromosomal metA, demonstrating the identity of the cloned gene. The C. glutamicum metA mutant lost the ability to grow on glucose minimal medium supplemented with homoserine. However, the mutant could grow on a minimal medium supplemented with cystathionine, demonstrating that C. glutamicum uses the cystathionine route to synthesize methionine. Introduction of a plasmid carrying cloned metA into C. glutamicum resulted in a 10-fold increase in enzyme activities and expression of a protein product of M(r) 41,000, which agrees with the sequence data and is similar in size to those of other homoserine acetyltransferases. Unlike E. coli whose metA product uses succinyl coenzyme A as a substrate, the cloned metA gene produced homoserine acetyltransferase which uses only acetyl coenzyme A as the acyl donor. Title: In vitro metabolism of the new insecticide flupyrazofos by rat liver microsomes Lee HS, Jeong S, Kim K, Kim JH, Lee SK, Kang BH, Roh JK Ref: Xenobiotica, 27:423, 1997 : PubMed ESTHER: Lee_1997_Xenobiotica_27_423 PubMedSearch: Lee 1997 Xenobiotica 27 423 PubMedID: 9179985 Inhibitor(s) related to this paper: Flupyrazofos Abstract 1. The in vitro metabolism of the new insecticide flupyrazofos was studied using rat liver microsomes. Two metabolites were produced and identified as O,O-diethyl O-(1-phenyl-3-trifluoromethyl-5-pyrazoyl) phosphoric acid ester (flupyrazofos oxon) and 1-phenyl-3-trifluoromethyl-5-hydroxypyrazole (PTMHP) based on UV and mass spectral analysis. 2. Cytochrome P450 oxidatively converted flupyrazofos to flupyrazofos oxon, a major metabolite and phenobarbital-induced microsomes increased this desulphuration by 8-fold. 3. Flupyrazofos oxon was converted to PTMHP with a half-life of 47.8 min by chemical hydrolysis and this conversion also proceeded non-enzymatically under our microsomal incubation conditions. Title: Role of bile salt-dependent cholesteryl ester hydrolase in the uptake of micellar cholesterol by intestinal cells Shamir R, Johnson WJ, Zolfaghari R, Lee HS, Fisher EA Ref: Biochemistry, 34:6351, 1995 : PubMed ESTHER: Shamir_1995_Biochemistry_34_6351 PubMedSearch: Shamir 1995 Biochemistry 34 6351 PubMedID: 7756263 Abstract The bile salt-dependent cholesteryl ester hydrolase (CEH; EC 3.1.1.13) has been proposed to promote the intestinal absorption of both the free and esterified (FC, CE) forms of dietary cholesterol. For example, it was recently reported that in the human intestinal cell line CaCo2, addition of bovine CEH to the medium increased the uptake and intracellular esterification of micellar FC supplied at subphysiological concentrations [Lopez-Candales et al. (1993) Biochemistry 32, 12085-12089]. To test the ability of CEH to promote micellar cholesterol uptake in a CaCo2 system under more physiological conditions, an in vitro model was developed. Cells stably expressing rat CEH were created by DNA transfection (Tr cells), and the uptake of micellar FC and its intracellular esterification were measured using isotopic methods in Tr and control cells. Experimental parameters that were varied included micellar composition (monoolein or egg PC; FC, CE, or both), the final concentration of micellar cholesterol (1 nM to 50 microM), the origin of CEH (endogenously synthesized vs exogenously added), and the species source of enzyme (rat, pig, man). The uptake of cholesterol that was derived from micellar CE was significantly increased 5-10-fold (p < 0.001) in Tr vs control cells as a result of the hydrolysis of the CE by the CEH and subsequent uptake of the liberated free cholesterol. In contrast, the uptake of micellar FC was not increased by the presence of CEH, whether it was endogenous or exogenous. In addition, based on TLC analysis of extracted cellular lipids, there was no evidence that CEH promoted the esterification of the FC that was taken up.(ABSTRACT TRUNCATED AT 250 WORDS) Title: Organophosphate poisoning in a factory: relationship to workload and production volume Tay P, Lee HS Ref: Singapore Medical Journal, 35:541, 1994 : PubMed ESTHER: Tay_1994_Singapore.Med.J_35_541 PubMedSearch: Tay 1994 Singapore.Med.J 35 541 PubMedID: 7701384 Abstract In Singapore, all workers exposed to organophosphate compounds are required to undergo Statutory Medical Examinations. In this paper, the relationship between workload and worker exposure to these compounds is illustrated. In addition, the importance of performing detailed clinical examinations and baseline red blood cell acetylcholinesterase estimations for all organophosphate exposed workers is emphasised. | |||||||
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