• Asian Pacific Journal of Cancer Prevention
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• v.14 no.12
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• pp.7045-7056
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• 2013

Since the first report of RNA interference (RNAi) less than a decade ago, this type of molecular intervention has been introduced to repress gene expression in vitro and also for in vivo studies in mammals. Understanding the mechanisms of action of synthetic small interfering RNAs (siRNAs) underlies use as therapeutic agents in the areas of cancer and viral infection. Recent studies have also promoted different theories about cell-specific targeting of siRNAs. Design and delivery strategies for successful treatment of human diseases are becomingmore established and relationships between miRNA and RNAi pathways have been revealed as virus-host cell interactions. Although both are well conserved in plants, invertebrates and mammals, there is also variabilityand a more complete understanding of differences will be needed for optimal application. RNA interference (RNAi) is rapid, cheap and selective in complex biological systems and has created new insight sin fields of cancer research, genetic disorders, virology and drug design. Our knowledge about the role of miRNAs and siRNAs pathways in virus-host cell interactions in virus infected cells is incomplete. There are different viral diseases but few antiviral drugs are available. For example, acyclovir for herpes viruses, alpha-interferon for hepatitis C and B viruses and anti-retroviral for HIV are accessible. Also cancer is obviously an important target for siRNA-based therapies, but the main problem in cancer therapy is targeting metastatic cells which spread from the original tumor. There are also other possible reservations and problems that might delay or even hinder siRNA-based therapies for the treatment of certain conditions; however, this remains the most promising approach for a wide range of diseases. Clearly, more studies must be done to allow efficient delivery and better understanding of unwanted side effects of siRNA-based therapies. In this review miRNA and RNAi biology, experimental design, anti-viral and anti-cancer effects are discussed.

• Molecules and Cells
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• v.40 no.9
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• pp.655-666
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• 2017

We constructed a large $na{\ddot{i}}ve$ human Fab library ($3{\times}10^{10}$ colonies) from the lymphocytes of 809 human donors, assessed available diversities of the heavy-chain variable (VH) and ${\kappa}$ light-chain variable (VK) domain repertoires, and validated the library by selecting Fabs against 10 therapeutically relevant antigens by phage display. We obtained a database of unique 7,373 VH and 41,804 VK sequences by 454 pyrosequencing, and analyzed the repertoires. The distribution of VH and VK subfamilies and germline genes in our antibody repertoires slightly differed from those in earlier published natural antibody libraries. The frequency of somatic hypermutations (SHMs) in heavy-chain complementarity determining region (HCDR)1 and HCDR2 are higher compared with the natural IgM repertoire. Analysis of position-specific SHMs in CDRs indicates that asparagine, threonine, arginine, aspartate and phenylalanine are the most frequent non-germline residues on the antibody-antigen interface and are converted mostly from the germline residues, which are highly represented in germline SHM hotspots. The amino acid composition and length-dependent changes in amino acid frequencies of HCDR3 are similar to those in previous reports, except that frequencies of aspartate and phenylalanine are a little higher in our repertoire. Taken together, the results show that this antibody library shares common features of natural antibody repertoires and also has unique features. The antibody library will be useful in the generation of human antibodies against diverse antigens, and the information about the diversity of natural antibody repertoires will be valuable in the future design of synthetic human antibody libraries with high functional diversity.

• Journal of Life Science
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• v.20 no.2
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• pp.183-189
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• 2010

A fibrinolytic enzyme producing Bacillus sp. J-19 was isolated from the popular Korean seasoning, pickled anchovy. The fibrinolytic enzyme was purified to homogeneity by chromatographic methods including ethanol precipitation and gel-filtration using Sephadex G-50. Compared to the crude enzyme extract, the specific activity of the enzyme increased 1021-fold with a recovery of 23%. The purified enzyme was estimated to be approximately 45 kDa by SDS-PAGE. Especially, the amidolytic activity in the presence of the synthetic substrate for serine protease (H-D-Ile-Pro-Arg-pNA, S-2288) represented approximately 17 U/mg. In addition, more than the 60% activity of the 45 kDa fibrinolytic activity was maintained in the presence of up to 30% (w/v) sodium chloride. These findings could provide a unique fibrinolytic enzyme, leading to a potential thrombolytic agent.

• Journal of Life Science
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• v.30 no.5
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• pp.420-427
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• 2020

A repebody, an artificial non-immunoglobulin protein scaffold, is expected to be a solution in the search for faster, cheaper, and customizable antibodies. However, the production of medical repebodies remains difficult due to their low yield and the complex purification processes required. The Pseudomonas fluorescens ABC transporter system has been suggested as an efficient and cost-effective method for repebody production, but the total yield is low because of the secreted protein's positive charge; thus, a repebody with a high isoelectric point needs to be changed into a more negatively charged protein for better secretion. To achieve this, we first attached oligo-aspartic acids to the N- and C-terminals of the repebody, but secretion efficiency was not enhanced significantly. Subsequently, we devised an alternative method for improved secretion efficiency by engineering fifteen positively charged amino acids to aspartic acid in the non-antigen binding sites of the repebody to give a high net negative charge. As a result, secretion efficiency was greatly enhanced from 21.2% (wildtype) to 58.5% (negatively supercharged). The negatively supercharged repebody was succussfully produced extracellularly by ABC transporter secretion system in P. fluorescens.

• Journal of Life Science
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• v.30 no.10
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• pp.919-929
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• 2020

Aromatic compounds are widely used in the chemical, food, polymer, cosmetic, and pharmaceutical industries and are produced by mainly chemical synthesis using benzene, toluene, and xylene or by plant extraction methods. Due to many rising threats, including the depletion of fossil fuels, global warming, the strengthening of international environmental regulations, and the excessive harvesting of plant resources, the microbial production of aromatic compounds using renewable biomass is regarded as a promising alternative. By integrating metabolic engineering with synthetic and systems biology, artificial biosynthetic pathways have been reconstituted from L-tryptophan biosynthetic pathway in relevant microorganisms, such as Escherichia coli and Corynebacterium glutamicum, enabling the production of a variety of value-added aromatic compounds, such as 5-hydroxytryptophan, serotonin, melatonin, 7-chloro-L-tryptophan, 7-bromo-L-tryptophan, indigo, indirubin, indole-3-acetic acid, violacein, and dexoyviolacein. In this review, we summarize the characteristics, usage, and biosynthetic pathways of these aromatic compounds and highlight the latest metabolic engineering strategies for the microbial production of aromatic compounds and suitable solution strategies to overcome problems in increasing production titers. It is expected that strain development based on systems metabolic engineering and the optimization of media and bioprocesses using renewable biomass will enable the development of commercially viable technologies for the microbial production of many aromatic compounds.

• Asian-Australasian Journal of Animal Sciences
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• v.23 no.12
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• pp.1566-1577
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• 2010

Nandrolone, 19-nortestosterone, is a synthetic androgenic-anabolic steroid promoting muscle growth. Nandrolone is also present in pig meat and sera at non-negligible levels. A number of scientific reports have suggested a positive relationship between incidence of infertility and increased meat consumption in humans. The present study was designed to determine out the effect of feeding nandrolone on the testis of the male reproductive tract. Mixtures of food and nandrolone at different concentrations (0.005 ppm and 0.5 ppm) were supplied to pubertal male rats for 6 weeks. Body weight was recorded every week during the entire experimental period. At the end of the treatment, the testis, epididymis, and epididymal fat were collected and weighted. Sperm numbers in the caudal epididymis were counted. Differential gene or protein expression of steroidogenic enzymes in the testes among experimental groups was determined by semi-quantitative real-time PCR or western blotting analysis, respectively. Histological changes of the testis induced by nandrolone treatment were examined by hematoxylin and eosin staining. Immunohistochemical analysis was employed to detect changes in the localization of steroidogenic enzymes in the testes among experimental animals. There were no significant changes on body, testis, epididymis, and epididymal fat weights among experimental groups. A significant increase of caudal sperm number was found in the 0.5 ppm nandrolone-treated group. Histological examination of the testes noted a high frequency of germ cell sloughing in seminiferous tubules of 0.5 ppm nandrolone-treated rats. Even though transcript levels of $3{\beta}$-hydroxysteroid dehydrogenase (HSD) I, $17{\beta}$-HSD4, and $17{\alpha}$-hydroxylase were influenced by nandrolone treatments, protein levels of all molecules examined in the present study were not significantly affected. Immunohistochemical analysis showed no visible changes in the localization of steroidogenic enzymes in the testes among experimental groups. The current study showed that oral intake of nandrolone in male rats for 6 weeks did not cause significant damage to the testis. It is considered that a feeding effect of nandrolone on male fertility would not be remarkable.

• Weed & Turfgrass Science
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• v.2 no.3
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• pp.221-229
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• 2013

This paper reviews current status of weed control practices in herbicide-resistant crops to examine weed management strategies in cope with cropping herbicide-resistant crops in the near future. Herbicide-resistant crops were rapidly adopted weed management technologies due to broad-spectrum weed control without crop injury. Transgenic glyphosate-resistant cultivars in soybean, corn, canola, and cotton were adopted to manage weeds at lower cost in a simplified weed management system. Dual stack crops with glyphosate and glufosinate resistance were developed to control glyphosate resistant weeds in corn, soybean and cotton. New multiple herbicide-resistant crops with resistance to glyphosate and glufosinate, acetolactate synthase (ALS) inhibitors, synthetic auxin herbicides, 4-hydroxyphenyl pyruvate dioxygenase (HPPD) inhibitors or acetyl Coenzyme A carboxylase (ACCase) inhibitors will expended the utility of existing herbicide technologies to manage the evolution of resistant weeds. However, herbicide resistant crops alone cannot solve weed problems and thus studies on diverse weed managements using an array of alternating herbicides of mode of action, mechanical, and cultural practices are needed for integrated weed management systems in the future.

• Journal of Life Science
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• v.23 no.7
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• pp.863-868
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• 2013

The XylP gene, which encodes endoxylanase in Bacillus sp. HY-20, was subcloned, and two expression plasmids, pG-xylP and pGMF-xylP were constructed. These plasmids, which contain different signal sequences, XylP s.s and $MF{\alpha}_{opt}$ s.s, respectively, for the secretory expression of endoxylanase, were transformed into Saccharomyces cerevisiae SEY2102 and FY833, respectively. The recombinant endoxylanases were successfully expressed, with a total activity range of 23.7-70.1 unit/ml according to the expression system and host strain. The endoxylanase activity in SEY2102/pGMF-xylP reached a maximum of 88.1 unit/ml in baffled flask culture. Most of the recombinant endoxylanase was efficiently secreted in the extracellular fraction, and the $MF{\alpha}_{opt}$ s.s was more efficient for secreting endoxylanase in yeast than the XylP s.s. Therefore, the expression system developed in this study produces large extracellular amounts of endoxylanase using S. cerevisiae as the host strain, and it could be used in bioethanol production and industrial applications.

• Korean journal of applied entomology
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• v.51 no.4
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• pp.469-477
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• 2012

Ostrinia larvae feed the pods and stem of red bean and seriously damage the bean production from farmers. In this study we investigated biological and developmental characteristics including field collection, host feeding preference, artificial rearing diet, morphological and molecular taxonomical identification, and pheromone analysis for an Ostrinia sp. in Korea. The male adults have massive tibia in the middle legs and 3-lobed uncus in the genitalia. The partial nucleotide sequences of mitochondrial cytochrome oxidase I (COI) and II (COII) were not corresponded to those DNA sequences from other Ostrinia species reported previously in Japan and China. Host plants for this species are also different from the previous species reported. In the gas chromatography (GC) analyses, (Z)-9-tetradecenyl acetate was not detected from the pheromone gland of our species while the component as a sex pheromone was found in O. zaguliaevi and O. zealis, With taken results, we conclude this Ostrinia species in Korea is Ostrinia scapulalis or closely related species. When larvae collected in a fall were incubated in the outdoor condition, they emerged to adult between June and July in the next year. The result indicates that the winter diapause could be started in late larval stage. In addition, we developed a semi-synthetic artificial diet adopted for mass rearing of the O. scapulalis in laboratory.

• The Korean Journal of Zoology
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• v.14 no.4
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• pp.175-180
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• 1971

The effects of X-irradiation on the mitotic activity, the chromosome aberration and the DNA synthetic pattern in synchronized human kidney cells treated with 5-AU were measured in the present experiment. When 5-AU was added, mitotic activity was markedly suppressed. After removal of the cells from the chemical, its activity proceeded synchronouly and reached peaks at hours 10. In 5-AU+100R groups, it was observed the X-ray caused mitotic delay, the irregularity of the time when mitotic peak appeared and the inhibiton of mitotic activity. In the control group, chromosome aerrations per cell was 0.030, whereas 0.147 in 5-AU treated group. In 5-AU+100R and 5-AU+200R groups, chromosome aberrations per cell were 0.583 and 0.669 respectively and the average chromosome aberrations per cell per R was 0.0035. 5-AU increased the frequency of labeled metaphases together with labeling intensity, and this is thought to be due to the accumulation of cells by 5-AU at S stage. On the contrary, X-ray decreased the labeling intensity and the frequency of labeled metaphases.