• Proceedings of the Korean Society for Applied Microbiology Conference
• /
• 2001.06a
• /
• pp.149-153
• /
• 2001

To investigate the mode of bactericidal action for antimicrobial peptide, pediocin, synthetic and mutant pediocins were prepared by direct chemical synthesis. Native pediocin was purified from Pedio-coccus acidilactici M and its conformational structure and bactericidal functions were analyzed and compared to synthetic pediocin. Schematic mode of pediocin actions, how pediocin binds on the target cell membrane, penetrates and makes tunnel are proposed. For these purposes, primary and secondary structures of pediocin was analyzed and disulfide bond assignment was also done. The pediocin purified from P. acidilactici M had high effective bactericidal ability against gram positive bacteria, especially Listeria monocytogenes and was very stable at extreme pHs and even at high temperatures such as autoclaving temperature (121$^{\circ}C$). Pediocin was consisted of 44 amino acids with four cysteines. Novel synthetic peptides were achieved by solid phase peptide synthesis(SPPS) method. To explain the function of cysteine in C-terminal region, mutant pediocin, Ped[C24A＋C44A], was synthesized and their structural and biological functions were analyzed. Second mutant pediocin, Ped[KllE], was prepared to explain the function of lysine at 11 of N-terminal part of pediocin, especially loop of $\beta$-sheet, and to predict the initial binding site of pediocin. The native and synthetic pediocins was showed random coil conformation by spectropolarimetry in moderate conditions. This conformation was observed in extreme conditions such as high temperature and low and high pHs, also. Circular dichroism(CD) data also showed the existence of $\beta$-turn structure in N-terminal part both native and synthetic pediocins. A structural model for pediocin predicts that 18 amino acids in the N-terminal part of the peptide assume a three-strand $\beta$-sheet conformation. This random coil in C-terminal part of pediocin was converted to folding structure, helix structure, in nonpolar solvents such as alcohol and TFE. The disulfide bond between $^{9}$ Cys and $^{14}$ Cys was concrete and inevitable, however, evidences of disulfide bond between $^{24}$ Cys and $^{44}$ Cys was not. Data of Ped[C24A＋C44A], pediocin mutant showed that $^{44}$ Cys was required during killing the target cells but not inevitable, since Ped[C24A＋C44A] still have bactericidal activity but much less than native pediocin. Another pediocin mutant, Ped[KllE], had still bactericidal activity, was controversial to propose that positive charge like as $^{11}$ Lys in loop or hinge in bacteriocin bound or helped to binding to microorganism with electrostatic interaction between cell membrane especially teichoic acid and positive amino acid nonspecifically. The conformation of pediocin among native, synthetic and mutant pediocins did not show big difference. The conformations between oxidized and reduced pediocin were almost similar regardless of native or synthetic.

• Journal of the Korean Wood Science and Technology
• /
• v.42 no.6
• /
• pp.708-713
• /
• 2014

Trusses are widely used for wooden houses in the areas where wood construction in generalized for residential housings such as North America, Australian, New Zealand. In Korea, joist and rafter system is generally used because of the production cost, transportation cost and lack of experience required for truss manufacturing. In this study, roof trusses and flat trusses were manufactured by using oriented strand board (OSB) gusset plates for field assembly and tested under bending load to obtain the allowable loads. The allowable load and the actual load of 6m span roof trusses were 10.60 kN and 5.26 kN, respectively, which is regarded to be sufficient for use in construction. The allowable load and the actual load of 6m span floor flat trusses were 7.18 kN and 7.43 kN, respectively. For flat trusses, the allowable load is slightly lower than the actual load but the difference in very small, and it is thought that flat trusses can be used for construction by applying small change of structures and members.

• Food Science of Animal Resources
• /
• v.26 no.1
• /
• pp.20-27
• /
• 2006

Effects of addition level of sodium chloride (NaCl) on gel properties of surimi-like pork (SLP) were investigated. Porcine semimembranosus muscle was used to manufacture SIP contained 1, 2, 3 and 4% NaCl to measure moisture content, pH, color, gel strength, micro-structure and sensory evaluation. The pH and moisture content of SLP were decreased as increasing of NaCl level. However, the gel strength of SLP was increased with increasing of NaCl level. Values of yellowness and chroma were lower in SLP of 2% and 3% NaCl compared with those of 1% and 4% NaCl. Amorphus protein particles size in micro-structure of SLP was decreased and coagulated as increasing level of NaCl. SLP of 1% NaCl had a structure formed by aggregates of densely packed globular proteins and arranged in clusters, whereas a well-structured matrix with a highly interconnected network of strand was observed in SLP of 4% NaCl. Result suggested that the increasing gel strength with NaCl level might be due to lower moisture content and denser micro-structure of gel.

• Toxicological Research
• /
• v.29 no.1
• /
• pp.43-52
• /
• 2013

Zearalenone (ZEN) is a non-steroidal estrogenic mycotoxin produced by several species of Fusarium that are found in cereals and agricultural products. ZEN has been implicated in mycotoxicosis in farm animals and in humans. The toxic effects of ZEN are well known, but the ability of an alkaline Comet assay to assess ZEN-induced oxidative DNA damage in Chang liver cells has not been established. The first aim of this study was to evaluate the Comet assay for the determination of cytotoxicity and extent of DNA damage induced by ZEN toxin, and the second aim was to investigate the ability of N-acetylcysteine amide (NACA) to protect cells from ZEN-induced toxicity. In the Comet assay, DNA damage was assessed by quantifying the tail extent moment (TEM; arbitrary unit) and tail length (TL; arbitrary unit), which are used as indicators of DNA strand breaks in SCGE. The cytotoxic effects of ZEN in Chang liver cells were mediated by inhibition of cell proliferation and induction of oxidative DNA damage. Increasing the concentration of ZEN increased the extent of DNA damage. The extent of DNA migration, and percentage of cells with tails were significantly increased in a concentration-dependent manner following treatment with ZEN toxin (p < 0.05). Treatment with a low concentration of ZEN toxin (25 ${\mu}M$) induced a relatively low level of DNA damage, compared to treatment of cells with a high concentration of ZEN toxin (250 ${\mu}M$). Oxidative DNA damage appeared to be a key determinant of ZEN-induced toxicity in Chang liver cells. Significant reductions in cytolethality and oxidative DNA damage were observed when cells were pretreated with NACA prior to exposure to any concentration of ZEN. Our data suggest that ZEN induces DNA damage in Chang liver cells, and that the antioxidant activity of NACA may contribute to the reduction of ZEN-induced DNA damage and cytotoxicity via elimination of oxidative stress.

• Korean Journal of Environmental Biology
• /
• v.24 no.1 s.61
• /
• pp.46-52
• /
• 2006

The mercury is among the most highly bioconcentrated toxic trace metals. Many national and international agencies and organisations have targeted mercury for the possible emission control. The mercury toxicity depends on its chemical form, among which alkylmercury compounds are the most toxic. A human cervix uterus cancer cell line HeLa cells was employed to investigate the effect of the toxic heavy metal mercury (Hg) and ionizing radiation. In the in vitro comet assays for the genotoxicity in the HeLa cells, the group of Hg treatment after irradiation showed higher DNA breakage than the other groups. The tail extent moment and olive tail moment of the control group were $4.88{\pm}1.00\;and\;3.50{\pm}0.52$ while the values of the only Hg treatment group were $26.90{\pm}2.67\;and\;13.16{\pm}1.82$, respectively. The tail extent moment and olive tail moment of the only 0.001, 0.005, 0.01 Hg group were $12.24{\pm}1.82,\;8.20{\pm}2.15,\;20.30{\pm}1.30,\;12.26{\pm}0.52,\;40.65{\pm}2.94\;and \;20.38{\pm}1.49$, respectively. In the case of Hg treatment after irradiation, the tail extent moment and olive tail moment of the 0.001, 0.005, 0.01 Hg group were $56.50{\pm}3.93,\;32.69{\pm}2.48,\;62.03{\pm}5.14,\;31.56{\pm}1.97,\;72.73{\pm}3.70\;and \;39.44{\pm}3.23$, respectively. The results showed that Hg induced DNA single-strand breaks or alkali labile sites as assessed by the Comet assay. It is in good agreement with the reported results. The mercury inhibits the repair of DNA. The bacterial formamidopyrimidine-DNA glycosylase (Epg protein) recognizes and removes some oxidative DNA base modifications. Enzyme inactivation by Hg (II) may therefore be due either to interactions with rysteine residues outside the metal binding domain or to very high-affinity binding of Hg (II) which readily removes Zn (II) from the zinc finger.

• Korean Journal of Head & Neck Oncology
• /
• v.19 no.2
• /
• pp.121-126
• /
• 2003

Objectives: The c-kit gene encodes a transmembrane receptor-type tyrosine kinase, which is known to have a significant role in the normal migration and development of germ cells and melanocytes. In the previous studies of c-kit gene, c-kit expressions showed only in adenoid cystic carcinomas, lymphoepithelioma-like carcinomas and myoepithelial carcinomas, but not in others and mutation was not found in any types of salivary carcinoma. We investigate the c-kit expression which may be useful to differentiating adenoid cystic carcinomas from others, and mutation of the gene which may not be exist nor the mechanism of c-kit activation in salivary carcinomas. Material and Methods: The archival tissue samples from 42 salivary carcinomas of major and minor salivary glands were studied for c-kit expression by immunohistochemistry and gene mutation by polymerase chain reaction amplification and single strand conformational polymorphism. Results: The c-kit expressions were noted in 22/24 adenoid cystic carcinomas, 7/9 mucoepidermoid carcinomas, 2/3 acinic cell carcinomas, 3/4 malignant mixed tumors, and one undifferentiated carcinoma. The mutation of c-kit gene was found in 3/24 adenoid cystic carcinomas, 3/8 mucoepidermoid carcinomas, one acinic cell carcinoma, and 2/4 malignant mixed tumors. Conclusion: c-kit protein overexpression is seen in a variety of salivary gland carcinomas, and the mutation of the gene may be the mechanism of c-kit activation in these neoplasms.

• Proceedings of the Korean Institute Of Construction Engineering and Management
• /
• autumn
• /
• pp.232-239
• /
• 2001

Young Jong Grand Bridge is approach traffic road of New Inchon International Airport which covers hub airport function in northeast asia. The total span length of this bridge is $4,420{\cal}m$ and this main bridge type is, the first in the world, Double Deck Self Anchored Suspension Bridge, designed as double deck systems to be arranged by road and railroad. Approach bridges to be connected with main span also are composed double deck steel truss and steel box girder to consider a continuity with this span. Our company erected $1,375{\cal}m$(about 60,000tons) of double deck steel truss bridge type which is composed by 6 traffic lane on upper deck and 4 traffic lane and Double track railroad on lower deck. The original installation method of this bridge was planed to install about 75 meters bridge blocks to use floating crane, after temporary bent was constructed between permanent piers. But this method which had to construct many temporary bents in the sea had the matter that construction periods can become lengthen and construction cost can be risen. To overcome the uncertainty to ensure high qualify of bridge and economic project execution, our company developed new bridge erection method to assure both quality control and economic construction work. The new erection method which was developed by us was one that could transport and install long bridge block, $120{\cal}m$ unit at a time and that temporary bent was not required. We hope that this paper is used as technical data which will erect bridge in the western sea and others marine region.

• Proceedings of the Korea Crystallographic Association Conference
• /
• 2003.05a
• /
• pp.18-18
• /
• 2003

Thioredoxin (Trx) is a small redox protein that is ubiquitously distributed from achaes to human. In diverse organisms, the protein is involved in various physiological roles by acting as electron donor and regulators of transcription and apoptosis as well as antioxidants. Sequences of Trx within various species are 27～69% identical to that of E. coli and all Trx proteins have the same overall fold, which consists of central five β strands surrounded by four α helices. The N-terminal cysteine in WCGPC motif of Trx is redox sensitive and the motif is highly conserved. Compared with general cysteine, the N-terminal cysteine has low pKa value. The result leads to increased reduction activity of protein. Recently, novel thio.edoxin-related protein (TRP14) was found from rat brain. TRP14 acts as disulfide reductase like Trx1, and its redox potential and pKa are similar to those of Trx1. However, TRP14 takes up electrons from cytosolic thioredoxin reductase (TrxR1), not from the mitochondrial thioredoxin reductase (TrxR2). Biological roles of TES14 were reported to be involved in regulating TNF-α induced signaling pathways in different manner with Trx1. In depletion experiments, depletion of TRP14 increased TNF-α induced phosphorylation and degradation of IκBα more than the depletion Trx1 did. It also facilitated activation of JNK and p38 MAP kinase induced by TNF-α. Unlike Trx1, TRP14 shows neither interaction nor interference with ASK1. Here, we determined three-dimensional crystal structure of TRP14 by MAD method at 1.8Å. The structure reveals that the conserved cis-Pro (Pro90) and active site-W-C-X-X-C motif, which may be involved in substrate recognition similar to Trx1 , are located at the beginning position of strand β4 and helix α2, respectively. The TRP14 structure also shows that surface of TRP14 in the vicinity of the active site, which is surrounded by an extended flexible loop and an additional short a helix, is different from that of Trx1. In addition, the structure exhibits that TRP14 interact with a distinct target proteins compared with Trx1 and the binding may depend mainly on hydrophobic and charge interactions. Consequently, the structure supports biological data that the TRP14 is involved in regulating TNF-α induced signaling pathways in different manner with Trx1.

• Korean Journal of Veterinary Research
• /
• v.44 no.3
• /
• pp.379-387
• /
• 2004

When an organism is exposed to various toxicants chronically, reactive oxygen species(ROS) are accumulated and eventually result in several biological effects from gene expression to cell death. In the present study we investigated the oxidative damage of 2, 3, 7, 8-tetrachlorodibenzo-p-dioxin(TCDD) and/or benzo(a)pyrene (B(a)P) in C100 cells. C100 cells treated with TCDD(30 nM) and B(a)P($3{\mu}M$) underwent diverse oxidative stress as determined through thiobarbituric acid-reactive substances(TBARS) formation, DNA fragmentation, DNA single strand break(SSB) assay, immunohistochemical staining of 8-hydroxy-2'-deoxyguanosine(8-OHdG), and mRNA expressions of antioxidant enzymatic genes such as Cu/Zn-SOD gene, GPx(glutathione peroxidase 5) gene, and catalase gene. Lipid peroxidation in C100 cells was determined through measuing the formation of TBARS. For theat, the cells were pretreated with TCDD(30 nM) and/or B(a)P($3{\mu}M$) for 0.5, 1, 2 and 4 days. TBARS formation was increased in TCDD(30 nM) and B(a)P($3{\mu}M$) and mixture($30nM\;TCDD+3{\mu}M\;B(a)P$) and positive control treatment groups comparing to the controls. Mixture treatment induced more DNA fragmentation than the single treatment group at day 6. Also, SSB in all treatment groups was clearly observed when compared with the negative control group. As with the expression of antioxidant enzyme, GPx 5mRNA, B(a)P alone and mixture($30nM\;TCDD+3{\mu}M\;B(a)P$) treatment were higher comparing to those of the negative control and TCDD treatment groups. Our results suggest that exposure of C100 cells to mixture of TCDD and B(a)P leads to significant oxidative damage comparing to the exposures to the individual chemicals. Mechanisms of action are discussed. Additional studies are needed to elucidate the detailed mechanism of mixture-induced toxicity.

• Journal of Life Science
• /
• v.23 no.10
• /
• pp.1183-1191
• /
• 2013

Human apurinic/apyrimidinic endonuclease (APEX-1) is a multifunctional protein that is capable of repairing abasic sites and single-strand breaks in damaged DNA. In addition, it serves as a redox-modifying factor for a number of transcription factors. Identifying the transcriptional targets of APEX-1 is essential for understanding how it affects various cellular outcomes. Expression array analysis was used to identify glial cell-derived neurotropic factor receptor ${\alpha}1$ ($GFR{\alpha}1$), which is an encoding receptor for the glial cell-derived neurotropic factor (GDNF) family, the expression of which is induced by APEX-1. A target of GDNF/$GFR{\alpha}$ signaling, c-Src (Tyr418) was strongly phosphorylated by GNDF in the APEX-1 expressing cells. Moreover, GDNF initiated cell proliferation, measured by counting the number of cells, in the APEX-1 expressing cells. Importantly, the down-regulation of APEX-1 by siRNA caused a marked reduction in the $GFR{\alpha}1$ expression level, and it reduced the ability of GDNF to phosphorylate c-Src (Tyr418) and stimulate cell proliferation. These results demonstrate an association between APEX-1 and GDNF/$GFR{\alpha}$ signaling and suggest a potential molecular mechanism for the involvement of APEX-1 in cell survival and proliferation.