• Journal of Veterinary Science
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• v.22 no.1
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• pp.12.1-12.11
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• 2021

Background: Bats have been considered natural reservoirs for several pathogenic human coronaviruses (CoVs) in the last two decades. Recently, a bat CoV was detected in the Republic of Korea; its entire genome was sequenced and reported to be genetically similar to that of the severe acute respiratory syndrome CoV (SARS-CoV). Objectives: The objective of this study was to compare the genetic sequences of SARS-CoV, SARS-CoV-2, and the two Korean bat CoV strains 16BO133 and B15-21, to estimate the likelihood of an interaction between the Korean bat CoVs and the human angiotensin-converting enzyme 2 (ACE2) receptor. Methods: The phylogenetic analysis was conducted with the maximum-likelihood (ML) method using MEGA 7 software. The Korean bat CoVs receptor binding domain (RBD) of the spike protein was analyzed by comparative homology modeling using the SWISS-MODEL server. The binding energies of the complexes were calculated using PRODIGY and MM/GBGA. Results: Phylogenetic analyses of the entire RNA-dependent RNA polymerase, spike regions, and the complete genome revealed that the Korean CoVs, along with SARS-CoV and SARS-CoV-2, belong to the subgenus Sarbecovirus, within BetaCoVs. However, the two Korean CoVs were distinct from SARS-CoV-2. Specifically, the spike gene of the Korean CoVs, which is involved in host infection, differed from that of SARS-CoV-2, showing only 66.8%-67.0% nucleotide homology and presented deletions within the RBD, particularly within regions critical for cross-species transmission and that mediate interaction with ACE2. Binding free energy calculation revealed that the binding affinity of Korean bat CoV RBD to hACE2 was drastically lower than that of SARS-CoV and SARS-CoV-2. Conclusions: These results suggest that Korean bat CoVs are unlikely to bind to the human ACE2 receptor.

• Journal of Life Science
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• v.21 no.5
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• pp.693-699
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• 2011

Spermidine is a ubiquitous polycation that is synthesized from putrescine, which serves as a precursor of spermine. In recent years, spermidine was found to be a polyamine that plays an important role in longevity. Reactive oxygen species (ROS) such as hydroxyl radical, superoxide and hydrogen peroxide have been shown to be involved in various pathogenic processes as well as aging. The direct scavenging effect of spermidine on DPPH radical, $H_2O_2$ and hydroxyl radical, and its protective effect against DNA oxidation related to oxidative stress were evaluated in vitro. It was observed that spermidine exhibits scavenging activities on DPPH radical and H2O2 above 500 ${\mu}M$. Spermidine was especially effective in exerting a scavenging activity on hydroxyl radical. In addition, spermidine at 1000 ${\mu}M$ showed a clear protective effect against DNA oxidation. Furthermore, the expression level of anti-oxidant enzymes such as superoxide dismutase in humam dermal fibroblasts increased in the presence of spermidine compared with blank group. These results suggest that spermidine can be used as an antioxidant to prevent ROS-related diseases including inflammation, cancer and aging.

• Journal of Life Science
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• v.21 no.2
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• pp.286-291
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• 2011

Hypoxia is a common condition found in a wide range of solid tumors and is often associated with metastasis and poor clinical outcomes. In the present study, we found that HIF-$1{\alpha}$ was induced by cobalt chloride (500 ${\mu}M$) treatment on human lung cancer cells, A549 and H460, for 24 hr. However, cobalt chloride (500 ${\mu}M$) did not affect cell proliferation of A549 and H460 in 48 hr. Cobalt chloride (500 ${\mu}M$) additionally induced epithelial-to-mesenchymal-like transition (EMT) such as reduced E-cadherin expression and increased ${\alpha}$-SMA expression. These results were confirmed by immunofluorecence experiment in H460 cells. E-cadherin was localized on the outer cell membrane. However, when the cells were treated with 500 ${\mu}M$ cobalt chloride for 24 hr, diffuse E-cadherin staining was observed, characteristic of a migratory mesenchymal phenotype. We also found that cobalt chloride induced integrin ${\beta}3$ expression and FAK phosphorylation in human lung cancer cells using western blotting and FACS anlaysis. Our data suggest that integrin ${\beta}3$-induced FAK phosphorylation may be developed into target molecules for blocking tumor metastasis.

• Journal of Embryo Transfer
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• v.22 no.1
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• pp.39-45
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• 2007

This study was performed to induce the estrus in 9 anestrus Shih-tzu bitches by intramuscular injection of pregnant mare serum gonadotrophin (PMSG) 50IU/kg for 10 consecutive days and by intravenous injection of human chorionic gonadotrophin (hCG) 1,000IU/Head on Day 10. The day when the first injection of PMSG was counted as Day 0 of experiment. All of the bitches were monitored by vaginal discharges, displays the perineal region, vaginal swelling and male acceptances. The 9 bitches (100%) showed vaginal discharges and vaginal swelling, and were mated. The 5 bitches out of 9 bitches were pregnant (55.6%) and 4 bitches were non-pregnant (44.4%). The 3 bitches out of 5 pregnant bitches were spontaneously delivered (33.3%) and litter size were $1.66{\pm}1.15\;(1{\sim}3\;pups)$ pups. The 2 bitches were diagnosed as early embryonic death on days 38 and 41 after first injection of PMSG. These results indicated that rates of estrus induction, pregnancy and delivery were 100%, 55.6% and 33.3%, respectively, using PMSG and hCG.

• Korean Journal of Child Studies
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• v.25 no.2
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• pp.19-39
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• 2004

Mothers of 58 20-month-olds in Seoul, the Republic of Korea, completed vocabulary checklists for their children. When vocabulary level was taken into account, children's vocabularies contained relatively greater proportions of nouns than other word classes, and more verbs than adjectives or closed-class words. Correlations among word classes showed that each word class was consistently positively correlated with every other class. Girls' vocabularies showed evidence of being larger than boys. Large individual differences in the sizes of children's vocabularies were found. Factors that influence vocabulary size and can account for gender and individual differences are discussed. Noun prevalence in the vocabularies of children learning to speak Korean, and the merits of several theories that may account for this word-class prevalence pattern, are evaluated.

• The Korean Journal of Physiology and Pharmacology
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• v.15 no.4
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• pp.241-244
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• 2011

A lectin from the hemolymph of purse crab, Philyra pisum, was found to have anti-proliferative activity on human lung cancer cells by our laboratory. In this study, P. pisum lectin (PPL) was molecularly characterized including molecular mass, amino acid sequences, amino acid composition, and the effects of metal ions, temperature, and pH on the activity. We found that PPL showed mitogenic activity on human lymphocytes and BALB/c mouse splenocytes. The mitogenic activity (maximum stimulation index, $SI=9.57{\pm}0.59$) of PPL on human lymphocytes was higher than that of a standard well-known plant mitogen, concanavalin A (maximum $SI=8.80{\pm}0.59$). The mitogenic activity mediated by PPL is required for optimum dosing, and higher or lower concentrations caused decreases in mitogenic response. PPL also induced mitogenic activity on mouse splenocytes, however, the maximum SI ($1.77{\pm}0.09$) on mouse splenocytes of PPL was lower than that ($2.14{\pm}0.15$) of concanavalin A. In conclusion, PPL is a metal ion-dependent monomer lectin with mitogenic activity, and could be used as a lymphocyte or splenocyte stimulator.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.1539-1542
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• 2008

Plasma is 4th state of matters, which consists of electrons, neutral, and ionized particles. In biomedical research, cold plasma, which is generated in atmospheric condition, has been applied to disinfect microorganisms such as bacteria and yeast cells. Because of its low temperature condition, the heat-sensitive medical device can be easily sterilized by the cold plasma treatment. In recent years, the effects of plasma on mammalian cells have arisen as a new issue. Generally, plasma induces intensity dependent necrotic cell death. In this research, we investigate the feasibility of cold plasma treatment for cancer therapy by conducting comparative study of plasma effects on normal and cancer cells. We use THLE-2 (human liver normal cell) and SK-Hep1 (human liver metathetic cancer cell) as our target cells. The needle type of cold plasma is generated by the Helium plasma device. Two types of cells have different onset plasma conditions for the necrosis, which may be explained by difference in electrical properties of these two cell types.

• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.6
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• pp.1194-1199
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• 1997

The effect of hot taste preference on selected immune responses was investigated in human peripheral immunocompetent cells. Human lymphocytes and natural killer(NK) cells were prepared at a concentration of 2$\times$$10^{6}$ cells/ml in RPMI-1640 containing 10% fetal bovine serum. Lymphocytes proliferation was determined with the [$^{3}H$]-thymidine pulse for 18hrs after concanavalin A, phytohemagglutinin, Salmonella typhimurium mitogen, or media alone. NK cell activity was measured by cytolysis of $^51Cr$-labeled target cells K562. Serum antibodies levels such as IgM, IgG, IgA were also measured by ELISA method. There was no difference of serum IgM level among the groups, but IgG and IgA levels were greater in the group with hot taste preference than those of the group without hot taste preference. In lymphocytes of the group with hot taste preference there was a greater mitogen-induced lymphocyte proliferative responses compared to the group without hot taste preference. In addition, NK cell activity in group with hot taste preference was lower than that of the group without hot taste preference. These results suggest that the eating habit of spicy food containing hot components may affect immune status by modulating selective immunocompetent cells function.

• YAKHAK HOEJI
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• v.33 no.5
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• pp.267-272
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• 1989

The durg-macromolecule conjugates i.e. 5-fluorouracil-1-acetyl-human serum albumin(FU-AA-HSA, 8) and 5-fluorouracil-1-acetyl-poly-L-lysine(FU-AA-polylys, 9) have been synthesized and purified by sephadex G-25 gel filtration with 0.05M phosphate buffer(pH 7.5). The analyses of conjugates gave the molar ratio of FU-AA : HSA of 70-100:1 and FU-AA: poly-L-lysine of 109:1. The weight percent of FU-AA(as $FU-CH_2CO-$) in FU-AA-HSA conjugate was 16-22% and the one in FU-AA-polylys was 22.4%.

• The Korean Journal of Oral and Maxillofacial Pathology
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• v.41 no.1
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• pp.1-7
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• 2017

Lycorine, a natural alkaloid extracted from the Amaryllidaceae plant family, was reported to various physiological and pharmacological effects including anti-cancer activity. Nevertheless, there is no report of the anticancer effect of lycorine in oral cancer cells. The effects of lycorine on cell proliferation and apoptosis were examined through trypan blue exclusion assay, 4'-6-diamidino-2-phenylindole (DAPI) stain, Live/Dead assay, Western blot analysis and RT-PCR. Lycorine suppressed cell viability and induced apoptosis in MC3 and HSC-3 cell lines. Lycorine decreased survivin protein but did not affect its mRNA. It regulated survivin through accelerating protein degradation in a time-dependent manner although neither proteasome nor lysosome was not associated with lycorine-mediated protein degradation. Collectively, our results suggest that lycorine may be a potential therapeutic anti-cancer drug candidate for the treatment of human oral cancer.