• Korean Journal of Biological Psychiatry
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• v.8 no.2
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• pp.208-219
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• 2001

The pharmacotherapy of schizophrenia exhibits wide inter-individual variabilities in clinical efficacy and adverse effects. Recently, human genetic diversity has been known as one of the essential factors to the variation in human drug response. This suggests that drug therapy should be tailored to the genetic characteristics of the individual. Pharmacogenetics is the field of investigation that attempts to elucidate genetic basis of an individual's responses to pharmacotherapy, considering drug effects divided into two categories as pharmacokinetics and pharmacodynamics. The emerging field of pharmacogenomics, which focuses on genetic determinants of drug response at the level of the entire human genome, is important for development and prescription of safer and more effective individually tailored drugs and will aid in understanding how genetics influence drug response. In schizophrenia, pharmacogenetic studies have shown the role of genetic variants of the cytochrome P450 enzymes such as CYP2D6, CYP2C19, and CYP2A1 in the metabolism of antipsychotic drugs. At the level of drug targets, variants of the dopamine $D_2$, $D_3$ and $D_4$, and 5-$HT_{2A}$ and 5-$HT_{2C}$ receptors have been examined. The pharmacogenetic studies in schizophrenia presently shows controversial findings which may be related to the multiple involvement of genes with relatively small effects and to the lack of standardized phenotypes. For further development in the pharmacogenomics of schizophrenia, there would be required the extensive outcome measures and definitions, and the powerful new tools of genomics, proteomics and so on.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.30 no.5
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• pp.804-808
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• 1997

The genetic differentiation and characteristics of two oyster populations (Crassostrea gigas) in Korea were assessed based on the restriction fragment length polymorphisms (RFLP) analysis and the restriction patterns of subcloned mtDNA. The restriction fragments of twenty individuals in West Sea revealed an identical pattern, determined by 8 restriction enzymes. On the other hand, two haplotypes having variation at the HindIII site were shown in the specimens from South Sea; minor haplotypes (4 of 20) were similar to the results obtained from individuals in West Sea while major haplotypes were different from those in West Sea. It was suggested that oysters (C. gigas) of West Sea might have been introduced to South Sea. Each mitochondrial DNA from two oyster populations in Korea and from one in Japan was divided to three parts and subcloned into pUC19 to use in genetic studies effectively. Restriction map was constructed based on the cleavage pattern by multiple restriction enzymes.

• Journal of Microbiology and Biotechnology
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• v.26 no.12
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• pp.2184-2191
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• 2016

The time-consuming and high-cost preparation of soluble peptide-major histocompatibility complexes (pMHC) currently limits their wide uses in monitoring antigen-specific T cells. The single-chain trimer (SCT) of peptide-${\beta}2m$-MHC class I heavy chain was developed as an alternative strategy, but its gene fusion is hindered in many cases owing to the incompatibility between the multiple restriction enzymes and the restriction endonuclease sites of plasmid vectors. In this study, overlap extension PCR and one-step cloning were adopted to overcome this restriction. The SCT gene of the $OVA_{257-264}$ peptide-$(GS_4)_3-{\beta}2m-(GS_4)_4-H-2K^b$ heavy chain was constructed and inserted into plasmid pET28a by overlap extension PCR and one-step cloning, without the requirement of restriction enzymes. The SCT protein was expressed in Escherichia coli, and then purified and refolded. The resulting $H-2K^b/OVA_{257-264}$ complex showed the correct structural conformation and capability to bind with $OVA_{257-264}$-specific T-cell receptor. The overlap extension PCR and one-step cloning ensure the construction of single-chain MHC class I molecules associated with random epitopes, and will facilitate the preparation of soluble pMHC multimers.

• Journal of Microbiology and Biotechnology
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• v.27 no.11
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• pp.1952-1960
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• 2017

Recently, soybean isoflavone aglycones (i.e., daidzein and genistein) and ${\gamma}-aminobutyric$ acid (GABA) have begun to receive considerable consumer attention owing to their potential as nutraceuticals. To produce these ingredients, multiple microorganisms and their enzymes are commonly used for catalysis in the nutraceutical industry. In this work, we introduce a novel fermentation process that uses whole-cell biocatalysis to accelerate GABA and isoflavone aglycone production in doenjang (a traditional Korean soybean paste). Microbial enzymes transform soybean isoflavone glycosides (i.e., daidzin and genistin) and monosodium glutamate into soybean isoflavone aglycones and GABA. Lactobacillus brevis GABA 100 and Aspergillus oryzae KACC 40250 significantly reduced the production time with the aid of a protease. The resulting levels of GABA and daidzein were higher, and genistein production resembled the levels in traditional doenjang fermented for over a year. Concentrations of GABA, daidzein, and genistein were measured as 7,162, 60, and $59{\mu}g/g$, respectively on the seventh day of fermentation. Our results demonstrate that the administration of whole-cell L. brevis GABA 100 and A. oryzae KACC 40250 paired with a protease treatment is an effective method to accelerate GABA, daidzein, and genistein production in doenjang.

• Korean Journal of Occupational Health Nursing
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• v.22 no.4
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• pp.324-333
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• 2013

Purpose: This study was conducted to compare the changes in the levels of liver enzymes after providing health education to workers. Methods: Among 909 electronics-manufacturing workers, 96 (10.6%) workers had abnormal liver functions. Of these, male workers were randomly assigned into either the health education experimental group (48 [52.2%]) or the control group (44 [47.8%]). Depending on the level of participation in the health education, workers in the experimental group were classified into the participation (32 [34.8%]) and non-participation groups (16 [17.4%]). Changes in the levels of liver enzymes were compared among three groups. Results: The changes in the levels of gamma-glutamyltransferase (r-GTP) in the participation, non-participation, and control groups were $-25.3{\pm}54.5$ IU/L, $-4.4{\pm}24.1$ IU/L, and $-5.3{\pm}38.8$ IU/L, respectively (p=.036). Aspartate transaminase, alanine transaminase, waist circumference, body mass index, daily alcohol consumption, weekly exercise, and changes in smoking habits in the 3 groups did not differ significantly. In the multiple linear regression analysis, the variable of education participation revealed a significant regression coefficient of -25.10 when the change in r-GTP levels was the dependent variable. Conclusion: A brief health education targeted towards the management of liver disease among workers improved r-GTP levels.

• Applied Chemistry for Engineering
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• v.31 no.2
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• pp.125-137
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• 2020

In recent years, toxic organophosphorus compounds (OPs) have been used for civilians, becoming a great threat to the world. Alternative to the current treatment policy unpredictable for any prevention, researches on bioscavenger as an improved treatment have been actively conducted. Bioscavengers refer to proteins and enzymes that prevent intoxication by inactivating or binding toxic OPs before they reaches the target. In particular, extensive efforts have been made to develop catalytic bioscavengers that quickly detoxify OPs even with a small dose of the protein by performing multiple binding and hydrolysis processes with OPs. This review introduces the latest studies and results for developing catalytic bioscavengers using molecular evolution and protein engineering techniques. We will briefly present some of the remaining challenges on developing enzymes into clinically approved drugs.

• Archives of Pharmacal Research
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• v.26 no.8
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• pp.631-637
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• 2003

Chloroquine has been used for many decades in the prophylaxis and treatment of malaria. It is metabolized in humans through the N-dealkylation pathway, to desethylchloroquine (DCQ) and bisdesethylchloroquine (BDCQ), by cytochrome P450 (CYP). However, until recently, no data are available on the metabolic pathway of chloroquine. Therefore, the metabolic pathway of chloroquine was evaluated using human liver microsomes and cDNA-expressed CYPs. Chloroquine is mainly metabolized to DCQ, and its Eadie-Hofstee plots were biphasic, indicating the involvement of multiple enzymes, with apparent $K_m and V_{max}$ values of 0.21 mM and 1.02 nmol/min/mg protein 3.43 mM and 10.47 nmol/min/mg protein for high and low affinity components, respectively. Of the cDNA-expressing CYPs examined, CYP1A2, 2C8, 2C19, 2D6 and 3A4/5 exhibited significant DCQ formation. A study using chemical inhibitors showed only quercetin (a CYP2C8 inhibitor) and ketoconazole (a CYP3A4/5 inhibitor) inhibited the DCQ formation. In addition, the DCQ formation significantly correlated with the CYP3A4/5-catalyzed midazolam 1-hydroxylation (r=0.868) and CYP2C8-catalyzed paclitaxel 6$\alpha$-hydroxylation (r = 0.900). In conclusion, the results of the present study demonstrated that CYP2C8 and CYP3A4/5 are the major enzymes responsible for the chloroquine N-deethylation to DCQ in human liver microsomes.

• Journal of Microbiology and Biotechnology
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• v.34 no.4
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• pp.949-957
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• 2024

There has been a growing interest in skin beauty and antimelanogenic products. Melanogenesis is the process of melanin synthesis whereby melanocytes are activated by UV light or hormone stimulation to produce melanin. Melanogenesis is mediated by several enzymes, such as tyrosinase (TYR), microphthalmia-associated transcription factor (MITF), tyrosinase-related protein-1 (TRP-1), and TRP-2. In this study, we investigated the effect of Tuber himalayense extract on melanin synthesis in α-melanocyte-stimulating hormone (α-MSH)-treated B16F10 melanoma cells. We confirmed that T. himalayense extract was not toxic to α-MSH-treated B16F10 melanoma cells and exhibited a significant inhibitory effect on melanin synthesis at concentrations of 25, 50, and 100 ㎍/ml. Additionally, the T. himalayense extract inhibited melanin, TRP-1, TRP-2, tyrosinase, and MITF, which are enzymes involved in melanin synthesis, in a concentration-dependent manner. Furthermore, T. himalayense extract inhibited the mitogen-activated protein kinase (MAPK) pathways, such as extracellular signal-regulated kinase-1/2 (ERK), c-Jun N-terminal kinase (JNK), and p38. Therefore, we hypothesized that various components of T. himalayense extract affect multiple factors involved in melanogenesis in B16F10 cells. Our results indicate that T. himalayense extract could potentially be used as a new material for preparing whitening cosmetics.

• Journal of Microbiology and Biotechnology
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• v.30 no.6
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• pp.937-945
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• 2020

N-acyl-homoserine lactone (AHL)-mediated quorum sensing (QS) plays a major role in development of biofilms, which contribute to rise in infections and biofouling in water-related industries. Interference in QS, called quorum quenching (QQ), has recieved a lot of attention in recent years. Rhodococcus spp. are known to have prominent quorum quenching activity and in previous reports it was suggested that this genus possesses multiple QQ enzymes, but only one gene, qsdA, which encodes an AHL-lactonase belonging to phosphotriesterase family, has been identified. Therefore, we conducted a whole genome sequencing and analysis of Rhodococcus sp. BH4 isolated from a wastewater treatment plant. The sequencing revealed another gene encoding a QQ enzyme (named jydB) that exhibited a high AHL degrading activity. This QQ enzyme had a 46% amino acid sequence similarity with the AHL-lactonase (AidH) of Ochrobactrum sp. T63. HPLC analysis and AHL restoration experiments by acidification revealed that the jydB gene encodes an AHL-lactonase which shares the known characteristics of the α/β hydrolase family. Purified recombinant JydB demonstrated a high hydrolytic activity against various AHLs. Kinetic analysis of JydB revealed a high catalytic efficiency (k_cat/K_M) against C4-HSL and 3-oxo-C6 HSL, ranging from 1.88 x 10⁶ to 1.45 x 10⁶ M^-1 s^-1, with distinctly low K_M values (0.16-0.24 mM). This study affirms that the AHL degrading activity and biofilm inhibition ability of Rhodococcus sp. BH4 may be due to the presence of multiple quorum quenching enzymes, including two types of AHL-lactonases, in addition to AHL-acylase and oxidoreductase, for which the genes have yet to be described.

• Proceedings of the Korean Society for Applied Microbiology Conference
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• 2002.10a
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• pp.18-25
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• 2002

The pikromycin biosynthetic system in Streptomyces venezuleae is unique for its ability to produce two groups of antibiotics that include the 12-membered ring macrolides methymycin and neomethymycin, and the 14-membered ring macrolides narbomycin and pikromycin. The metabolic pathway also contains two post polyketide-modification enzymes, a glycosyltransferase and P450 hydroxylase that have unusually broad substrate specificities. In order to explore further the substrate flexibility of these enzymes a series of hybrid polyketide synthases were constructed and their metabolic products characterized. The plasmid-based replacement of the multifunctional protein subunits of the pikromycin PKS in S. venezuelae by the corresponding subunits from heterologous modular PKSs resulted in recombinant strains that produce both 12- and 14-membered ring macrolactones with predicted structural alterations. In all cases, novel macrolactones were produced and further modified by the DesVII glycosyltransferase and PikC hydroxylase leading to biologically active macrolide structures. These results demonstrate that hybrid PKSs in S. venezuelae can produce a multiplicity of new macrolactones that are modified further by the highly flexible DesVII glycosyltransferase and PikC hydroxylase tailoring enzymes. This work demonstrates the unique capacity of the S. venezuelae pikromycin pathway to expand the toolbox of combinatorial biosynthesis and to accelerate the creation of novel biologically active natural products. The polyketide backbone of rifamycin B is assembled through successive condensation and ${\beta}$-carbonyl processing of the extender units by the modular rifamycin PKS. The eighth module, in the RifD protein, contains nonfunctional DH domain and functional KR domain, which specify the reduction of the ${\beta}$-carbonyl group resulting in the C-21 bydroxyl of rifamycin B. A four amino acid substitution and one amino acid deletion were introduced in the putative NADPH binding motif in the proposed KR domain encoded by rifD. This strategy of mutation was based on the amino acid sequences of the corresponding motif of the KR domain of module 3 in the RifA protein, which is believed dysfunctional, so as to introduce a minimum alteration and retain the reading frame intact, yet ensure loss of function. The resulting strain produces linear polyketides, from tetraketide to octaketide, which are also produced by a rifD disrupted mutant as a consequence of premature termination of polyketide assembly. Much of the structural diversity within the polyketide superfamily of natural products is due to the ability of PKSs to vary the reduction level of every other alternate carbon atom in the backbone. Thus, the ability to introduce heterologous reductive segments such as ketoreductase (KR), dehydratase (DH), and enoylreductase (ER) into modules that naturally lack these activities would increase the power of the combinatorial biosynthetic toolbox. The dehydratase domain of module 7 of the rifamycin PKS, which is predicted to be nonfunctional in view of the sequence of the apparent active site, was replaced with its functional homolog from module 7 of rapamycin-producing polyketide synthase. The resulting mutant strain behaved like a rifC disrupted mutant, i.e., it accumulated the heptaketide intermediate and its precursors. This result points out a major difficulty we have encountered with all the Amycolatopsis mediterranei strain containing hybrid polyketide synthases: all the engineered strains prepared so far accumulate a plethora of products derived from the polyketide chain assembly intermediates as major products instead of just analogs of rifamycin B or its ansamycin precursors.