• Korean Journal of Agricultural Science
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• v.44 no.4
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• pp.477-486
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• 2017

This review provides an overview of dietary nucleotides as an alternative to in-feed antibiotics for weaning pigs. Dietary nucleotides are composed of DNA or RNA molecules and are normally contained in protein-rich feed ingredient, brewer's yeast, yeast extract, and milk. Weaning pigs are suffering from several stresses, such as environmental challenges (i.e. crowding, transportation, and feeding). Such stressors can damage the intestinal epithelium and cause an invasion by Escherichia coli, secondary inflammatory responses, and post weaning diarrhea. To overcome weaning disorder, people often use antibiotics which reduce symptoms and boost growth performance. However, since antibiotics were banned due to concerns of antibiotic resistant bacteria, researchers are studying alternative materials to antibiotics. Dietary nucleotides are one of the alternative materials for replacing antibiotics and can be used in abnormal conditions, such as weaning diarrhea, low digestibility, and disease condition. Nucleotides have substances that have important roles in cell division and cell growth, affecting growth performance, intestinal condition, and immunological effect at the weaning stage. However, nucleotides' composition is very different between sources and this aspect makes it difficult to utilize nucleotides at the weaning stage. Therefore, this review paper focuses on i) the characteristics and functions of dietary nucleotides and ii) the effect of dietary nucleotides on the growth performance and immune system of pigs.

• Korean Journal of Food Science and Technology
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• v.8 no.1
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• pp.47-52
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• 1976

Growth inhibition and morphological alteration of Bacillus megaterium NRRL B-1368 in aflatoxin-containing TGY liquid media and its growth restoration in normal media were investigated. Crude aflatoxins $(B_1\;22.7%,\;B_2\;1.6%,\;G_1\;3.6\;%\;and\;G_2\;0.2%)$ at concentrations of more than $20{\mu}g/ml$ inhibited the growth of the microorganism and prevented the formation of septum, resulting in abnormal elongation and disturbance of cell division. The aberrant cells, however, grew normally by septum formation and cell division upon returning to aflatoxin-free culture media. It was, therefore, assumed that aflatoxin affects the function of mesosome related to septum formation in bacteria.

• Reproductive and Developmental Biology
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• v.33 no.2
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• pp.93-98
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• 2009

In this study, bovine Dnmt1 cDNA was sequenced and detected Dnmt1 mRNA level in bovine tissues by northern blot, methylation pattern of genome by southern blot, specific localization of Dnmt1 in mouse and bovine preimplantation embryos by immunocytostaining and Dnmt1 protein level in ovary and testis by western blot. Bovine Dnmt1 cDNA sequence showed more homology with that of human than mouse and rat. The RNA level of Dnmt1 was 10 times higher expression in placenta than other tissues. This indicates that placenta was hypermethylated compared to others organs. The genomic DNA could not be cut by a specific restriction enzyme (HpaII) in placenta, lung and liver of bovine. It suggests that Dnmt1 in some somatic cells was already methylated. Dnmt1, which has the antibody epitope 1316~1616, was distributed in nucleus and cytoplasm including the stage of pronuclear stage and maturation of oocyte and gradually weaken to blastocyst stage compare to negative. In addition, Dnmt1 was strongly expressed in tetraploid embryo and cloned 8-cell than IVF 8-cell. An aberrant pattern of DNA methylation in cloned embryo may be abnormal development of fetus, embryonic lethality and placenta dysfunction. The somatic specific band (190kDa) was appeared in ovary and testis, but oocyte specific band (175kDa) was not. Further investigations are necessary to understand the complex links between the methyltransferases and the transcriptional activity of genes in the cloned bovine tissues.

• Korean Journal of Plant Tissue Culture
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• v.25 no.3
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• pp.153-158
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• 1998

The internal structures of Arabidopsis thaliana infected with beet curly top virus (BCTV) were studied by light microscopy. Hyperplasia was observed in the inflorescence stems of Arabidopsis thaliana ecotype Sei-O at 2 weeks after BCTV-Logan inoculation and callus was induced on symptomatic tissues at 4 weeks after virus inoculation. The infection processes were revealed as follows: hyperplasia of phloem tissue, necrosis of hyperplastic phloems, lacuna formation of necrotic tissues, elongation and enlargement of cortex and epidermal cells surrounding the lacuna formed phloem tissues, induction of cell division in the enlarged cortex and epidermal cells, and induction of callus tissue. Callus formation on Arabidopsis was caused by the virus infection, and virus inclusion body was observed in both phloem and callus tissue by azure-A staining.

• Journal of Life Science
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• v.15 no.1 s.68
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• pp.124-131
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• 2005

The regulation of gene expression plays an important rolet in cell cycle controls. In this study, a novel $mas3^+$ (mitosis associated protein) gene, a homolog of human SMARCADl, was isolated and characterized from a fission yeast Schizosaccharomyces pombe. The overall homology between the helicase proteins of the two species is $87\%$. This DEAD/H box-containing molecule has seven highly conserved sequence regions that allow us to place it in the SNF2 family of the helicase superfamily. Knock-out cell of $mas3^+$ gene was constructed using kanMX6 as a selection marker. Survival of mas3 null mutant exposed to UV or MMS was similar to those of wild type cells. $mas3^+$ expression was lowest at $G_2$ and gradually increased. Cytokinesis of mas3 null mutant was abnormal at $26^{\circ}C\;and\;35^{\circ}C$ and a large number of multi-septate cells were produced. These results indicate that the $mas3^+$ is involved in cytokinesis and cell shape control.

• Journal of Physiology & Pathology in Korean Medicine
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• v.28 no.6
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• pp.621-629
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• 2014

This study aimed to evaluate the genotoxicity of GST (Gamisasangja-tang). For examining genotoxicity, we carried out bacterial reverse mutation assay, chromosome aberration assay, micronucleus induction test according to OECD guidelines. Bacterial reverse mutation assay: In GST treating group, regardless of existence S9 mix, revertant colonies counts appeared to be less than twice of negative control group and dose dependent increase. In positive control group, revertant colonies counts were shown to be more than twice of negative control croup. Chromosome aberration assay: All cell line showed repetition rate of abnormal chromosome aberration less than 5%, regardless of treating time, existence of S9 mix, and no significant change ($p{\succeq}0.05$) compared with negative control group. Micronucleus induction test: Micronucleated polychromatic erythrocytes (MNPCE) repetition rate of Polychromatic erythrocytes (PCE) showed no significant changes compared with negative control group ($p{\succeq}0.05$). PCE portion of total erythrocytes also showed no significant changes ($p{\succeq}0.05$). Our results showed that GST didn't induce any genotoxicity.

• Development and Reproduction
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• v.18 no.4
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• pp.197-212
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• 2014

Osteosarcoma (OS) is one of the most common malignant primary bone tumors and NF-${\kappa}B$ appears to play a causative role, but the mechanisms are poorly understood. OS is one of the pleomorphic, highly metastasized and invasive neoplasm which is capable to generate osteoid, osteoclast and osteoblast matrix. Its high incidence has been reported in adolescent and children. Cell signal cascade is the pivotal functional mechanism acquired during the differentiation, proliferation, growth and survival of the cells in neoplasm including OS. The major limitation to the success of chemotherapy in OS is the development of multidrug resistance (MDR). Answers to all such queries might come from the knock-in experiments in which the combined approach of miRNAs with NF-${\kappa}B$ pathway is put into use. Abnormal miRNAs can modulate several epigenetical switching as a hallmark of number of diseases via different cell signaling. Studies on miRNAs have opened up the new avenues for both the diagnosis and treatment of cancers including OS. Collectively, through the present study an attempt has been made to establish a new systematic approach for the investigation of microRNAs, bio-physiological factors and their target pairs with NF-${\kappa}B$ to ameliorate oncogenesis with the "bridge between miRNAs and NF-${\kappa}B$". The application of NF-${\kappa}B$ inhibitors in combination with miRNAs is expected to result in a more efficient killing of the cancer stem cells and a slower or less likely recurrence of cancer.

• Journal of Life Science
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• v.31 no.3
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• pp.266-279
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• 2021

The present study examined the cytotoxic effects of a Smilax china L. extract (SCLE) in human cancer (A-549, MCF-7, MDA-MB-231, U87-MG, AGS, MKN-74, and SNU-601) and normal MRC-5 fibroblasts, as well as in mesenchymal stem cells derived from dental tissue (DSC). The 50% inhibitory concentration (IC50) values for SCLE were significantly (p<0.05) lower in the cancer cell lines (A-549, MCF-7, MDA-MB-231, U87-MG, AGS, MKN-74 and SNU-601) than in the MRC-5 and DSC cells. Cell growth was significantly (p<0.05) more inhibited in the cancer cell lines treated with 200 ㎍/ml SCLE than in the normal MRC-5 and DSC, and anoikis-like floating cell morphology was observed in the SCLE-treated cancer cells. The cells detached by SCLE treatment were retrieved daily and assayed for viability and telomerase activity. Cells retrieved at 4 days showed significantly decreased viability and telomerase activity (p<0.05), as well as apoptosis-like abnormal morphology, when compared to cells retrieved in the previous 3 days. The ratio of apoptosis and cells in the G1 phase was significantly (p<0.05) increased in the A-549, AGS, and MCF-7 cancer cells treated with SCLE for 4 days compared to untreated controls. However, after SCLE treatment, cell adhesion was not increased by application of an inhibitor of the associated protein kinase (ROCK) that mainly contributes to the increase in cell attachment. This suggests that the cellular detachment by SCLE is probably controlled by a Rho-independent mechanism(s). These observations indicate that SCLE readily induces anoikis in cancer cells and could serve as a potent agent for cancer chemotherapy.

• Journal of Microbiology and Biotechnology
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• v.27 no.5
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• pp.878-895
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• 2017

Phosphorylation, a critical mechanism in biological systems, is estimated to be indispensable for about 30% of key biological activities, such as cell cycle progression, migration, and division. It is synergistically balanced by kinases and phosphatases, and any deviation from this balance leads to disease conditions. Pathway or biological activity-based abnormalities in phosphorylation and the type of involved phosphatase influence the outcome, and cause diverse diseases ranging from diabetes, rheumatoid arthritis, and numerous cancers. Protein tyrosine phosphatases (PTPs) are of prime importance in the process of dephosphorylation and catalyze several biological functions. Abnormal PTP activities are reported to result in several human diseases. Consequently, there is an increased demand for potential PTP inhibitory small molecules. Several strategies in structure-based drug designing techniques for potential inhibitory small molecules of PTPs have been explored along with traditional drug designing methods in order to overcome the hurdles in PTP inhibitor discovery. In this review, we discuss druggable PTPs and structure-based virtual screening efforts for successful PTP inhibitor design.

• Preventive Nutrition and Food Science
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• v.10 no.2
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• pp.161-166
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• 2005

We investigated the effect of pycnogenol (PYC) supplementation on retarding the immune dysfunction of CS7BL/6 mice after murine AIDS (MAIDS) development. Dysfunction of T and B cell mitogenesis from primary cultured splenocytes has been observed with retrovirus infection and PYC supplementation partially recovered the dysfunction of T and B cells. There was an abnormal shift of cytokine pattern with retrovirns infection, which was designated by the decreased secretion of Th1 cytokines and increased secretion of Th2 cytokines. PYC supplementation increased IL-2 and $IFN-\gamma$ secretion and decreased IL-4, IL-6, and $TNF-\alpha$ secretion, but it was not sufficient enough to maintain the normal level of these cytokines. Hepatic vitamin E level was significantly decreased by retrovirns infection, in accordance with increased hepatic lipid peroxidation level, whereas PYC supplementation normalized the hepatic level of vitamin E and lipid peroxidation. This study suggests that PYC supplementation may partially help retard the incidence of symptoms during MAIDS.