• Journal of Microbiology and Biotechnology
• /
• v.16 no.8
• /
• pp.1201-1209
• /
• 2006

The purpose of this study was to isolate probiotic lactic acid bacteria (LAB) that produce bile salt hydrolase (BSH), and to evaluate its effects on serum cholesterol level. One-hundred-twenty bacterial colonies were initially isolated from human feces, and five strains were selected after screening based on their resistance to acids, tolerance against bile salts, and inhibitory activity on Escherichia coli. The Lactobacillus plantarum strain with the highest level of BSH activity was identified using 16S rRNA sequences, and was named L. plantarum CK 102. L. plantarum CK 102 at a level of 1.36$\times$10$^8$cfu/ml survived in pH 2 buffer for 6 h and exhibited excellent tolerance for bile salt. Coculturing the strain with E. coli in MRS broth resulted in strong inhibition against growth of E. coli at 18 h. Furthermore, the potential effect of CK 102 on serum cholesterol level was evaluated in rats. Thirty-two rats [Sprague-Dawley (SD) male, 129$\pm$l g, 5 weeks old] were divided into four groups of eight each. For six weeks, Group 1 was fed a normal diet (negative control); Group 2 was fed a cholesterol-enriched diet (positive control); Group 3 was fed a cholesterol-enriched diet plus L. plantarum CK 102 at 1.0$\times$10$^7$cfu/ml; and Group 4 was fed a cholesterol-enriched diet plus L. plantarum CK 102 at 5.0$\times$10$^7$cfu/ml. Blood samples were collected, serum lipids were analyzed, and weights of the organs were measured. Total blood cholesterol level, triglyceride, LDL-cholesterol, and free-cholesterol values were lower in rats that were fed 1. plantarum CK 102 than in those not fed L. plantarum CK 102. This cholesterol lowering effect implies that L. plantarum CK 102 could be utilized as an additive for health-assistance foods. In conclusion, these results suggest that the 1. plantarum CK 102 isolated could be used commercially as a probiotic.

• Reproductive and Developmental Biology
• /
• v.29 no.2
• /
• pp.127-131
• /
• 2005

The objective of this study was to examine the effect of EGF on meiotic maturation and pronuclear (PN) formation of porcine oocytes. Prepubertal gilt cumulus-oocyte-complexes (COCs) aspirated from $2\~6mm$ follicles of abbatoir ovaries were matured in TCM199 containing 0.1mg/ml cysteine, $0.5{\mu}/ml$ FSH and LH, and EGF (0, 5, 10, 20, 40 ng/ml) for 22 hr at $39^{\circ}C$ in a humidified atmosphere of $5\%$ $CO_2$ in air. They were then cultured for an additional 22hr without hormones. In Experiment 1, to examine the nuclear maturation at 44hr of culture, the expanded cumulus cells were removed by vortexing for 1 min in 3 mg/ml hyaluronidase. The oocytes were fixed in acetic acid: methanol (1:3, v/v) at least for 48 hr and stained with $1\%$ orcein solution for 5 min. Nuclear status was classified as germinal vesicle (GV), germinal vesicle breakdown (GVBD), prophase-metaphase I (PI-MI), and PII-MII under microscope. In Experiment 2, to investigate PN formation, oocytes were fertilized with Percoll-treated freshly ejaculated sperm $(1\times10^5\; cells/ml)$ in mTBM with $0.3\%$ BSA and 2mM caffeine for 5hr, and cultured in NCSU-23 medium with $0.4\%$ BSA. At 6hr of culture, the embryos were fixed in $3.7\%$ formaldehyde for 48hr and stained with 10ug/ml propidium iodide for 30 min. PN status was classified as no or one PN (unfertilized), 2 PN (normal fertilized) and $\geq3$ PN (polyspermy). Differences between groups were analyzed using one-way ANOVA after arc-sine transformation of the proportional data. The rate of oocytes that had reached to PII-MII were significantly (P<0.05) higher in all groups added EGF than that of non-treated group $(67\%)$, but it did not differ among the all added groups $(86\%,\;85\%,\;79\%\;and\;81\%$, in 5, 10, 20 and 40 ng/ml EGF, respectively). No differences on the incidence of 2PN were observed in all treated groups $(25\%,\;30\%,\;33\%,\;29\%\;and\;29\%$, in 0, 5, 10, 20 and 40 ng/ml EGF, respectively), however, in non-treated group, polyspermy tended to be increased ($66\%\;vs\;. 58\%,\;54\%,\;52\%\;and\;55\%$, 0 vs. 5, 10, 20, 40 ng/ml EGF, respectively). These results suggest that EGF can be effectively used as an additive for enhancing oocyte maturation and reducing the incidence of polyspermy in pig.

• Journal of Microbiology and Biotechnology
• /
• v.27 no.6
• /
• pp.1138-1149
• /
• 2017

The use of microalgal biomass is an interesting technology for the removal of heavy metals from aqueous solutions owing to its high metal-binding capacity, but the interactions with bacteria as a strategy for the removal of toxic metals have been poorly studied. The goal of the current research was to investigate the potential of Burkholderia tropica co-immobilized with Chlorella sp. in polyurethane discs for the biosorption of Hg(II) from aqueous solutions and to evaluate the influence of different Hg(II) concentrations (0.041, 1.0, and 10 mg/l) and their exposure to different contact times corresponding to intervals of 1, 2, 4, 8, 16, and 32 h. As expected, microalgal bacterial biomass adhered and grew to form a biofilm on the support. The biosorption data followed pseudo-second-order kinetics, and the adsorption equilibrium was well described by either Langmuir or Freundlich adsorption isotherm, reaching equilibrium from 1 h. In both bacterial and microalgal immobilization systems in the co-immobilization of Chlorella sp. and B. tropica to different concentrations of Hg(II), the kinetics of biosorption of Hg(II) was significantly higher before 60 min of contact time. The highest percentage of biosorption of Hg(II) achieved in the co-immobilization system was 95% at pH 6.4, at 3.6 g of biosorbent, $30{\pm}1^{\circ}C$, and a mercury concentration of 1 mg/l before 60 min of contact time. This study showed that co-immobilization with B. tropica has synergistic effects on biosorption of Hg(II) ions and merits consideration in the design of future strategies for the removal of toxic metals.

• Clinical and Experimental Reproductive Medicine
• /
• v.24 no.1
• /
• pp.21-26
• /
• 1997

This study was undertaken to examine the expression of EGF-R protein on ICM obtained from mouse IVF/IVC blastocyst by immunosurgery and indirect immunofluorescence(IIF). ICM cells used for this experiment were obtained from immunosurgery of mouse blatstocysts produced at 96 h after IVF, and recovered ICMs were assayed for cell viability and expression of EGF-R. The results obtained in this experiment were summarized as follows: when blastocysts were exposed to rabbit anti-mouse serum (antiserum) for 15-30 min. and then transferred them to guinea pig serum (complement) for 15-60 min., recovery rates of isolated ICMs were 8.0-84.2%. Especially, the best recovery (84.2%) of ICMs was obtained when exposure time to antiserum and complement was 30 min. and 60 min., respectively. In addition, when viability of isolated ICMs after immunosurgery was assessed by live/dead staining method, in all groups viability (93.8-100.0%) of isolated ICMs were not damaged if separated from TE cell. Also, we detected the expression of EGF-R on ICM cell by IIF. Therefore, these results suggest that EGF-R expression on the ICMs can stimulate the higher usablity of exogenous EGF to improve the preimplantation embryo development in vitro.

• Asian Pacific Journal of Cancer Prevention
• /
• v.13 no.8
• /
• pp.4031-4036
• /
• 2012

Background: The negative signaling provided by interactions of the co-inhibitory molecule, programmed death-1 (PD-1), and its ligands, B7-H1 (PD-L1) and B7-DC (PD-L2), is a critical mechanism contributing to tumor evasion; blockade of this pathway has been proven to enhance cytotoxic activity and mediate antitumor therapy. Here we evaluated the anti-tumor efficacy of AAV-mediated delivery of the extracellular domain of murine PD-1 (sPD-1) to a tumor site. Material and Methods: An rAAV vector was constructed in which the expression of sPD-1, a known negative regulator of TCR signals, is driven by human cytomegalovirus immediate early promoter (CMV-P), using a triple plasmid transfection system. Tumor-bearing mice were then treated with the AAV/sPD1 construct and expression of sPD-1 in tumor tissues was determined by semi quantitative RT-PCR, and tumor weights and cytotoxic activity of splenocytes were measured. Results: Analysis of tumor homogenates revealed sPD-1 mRNA to be significantly overexpressed in rAAV/sPD-1 treated mice as compared with control levels. Its use for local gene therapy at the inoculation site of H22 hepatoma cells could inhibit tumor growth, also enhancing lysis of tumor cells by lymphocytes stimulated specifically with an antigen. In addition, PD-1 was also found expressed on the surfaces of activated CD8+ T cells. Conclusion: This study confirmed that expression of the soluble extracellular domain of PD-1 molecule could reduce tumor microenvironment inhibitory effects on T cells and enhance cytotoxicity. This suggests that it might be a potential target for development of therapies to augment T-cell responses in patients with malignancies.

• Asian-Australasian Journal of Animal Sciences
• /
• v.26 no.3
• /
• pp.433-442
• /
• 2013

This study aimed to compare the dynamics of air temperature and velocity under two different ventilation and housing systems during summer and winter in Korea. The $NH_3$ concentration of both housing systems was also investigated in relation to the pig's growth. The ventilation systems used were; negative pressure type for the enclosed pig house (EPH) and natural airflow for the conventional pig house (CPH). Against a highly fluctuating outdoor temperature, the EPH was able to maintain a stable temperature at 24.8 to $29.1^{\circ}C$ during summer and 17.9 to $23.1^{\circ}C$ during winter whilst the CPH had a wider temperature variance during summer at 24.7 to $32.3^{\circ}C$. However, the temperature fluctuation of the CPH during winter was almost the same with that of EPH at 14.5 to $18.2^{\circ}C$. The NH3 levels in the CPH ranged from 9.31 to 16.9 mg/L during summer and 5.1 to 19.7 mg/L during winter whilst that of the EPH pig house was 7.9 to 16.1 mg/L and 3.7 to 9.6 mg/L during summer and winter, respectively. These values were less than the critical ammonia level for pigs with the EPH maintaining a lower level than the CPH in both winter and summer. The air velocity at pig nose level in the EPH during summer was 0.23 m/s, enough to provide comfort because of the unique design of the inlet feature. However, no air movement was observed in almost all the lower portions of the CPH during winter because of the absence of an inlet feature. There was a significant improvement in weight gain and feed intake of pigs reared in the EPH compared to the CPH (p<0.05). These findings proved that despite the difference in the housing systems, a stable indoor temperature was necessary to minimize the impact of an avoidable and highly fluctuating outdoor temperature. The EPH consistently maintained an effective indoor airspeed irrespective of season; however the CPH had defective and stagnant air at pig nose level during winter. Characteristics of airflow direction and pattern were consistent relative to housing system during both summer and winter but not of airspeed. The ideal air velocity measurement favored the EPH and therefore can be appropriate for the Korean environment. Further emphasis on its cost effectiveness will be the subject of future investigations.

• Asian Pacific Journal of Cancer Prevention
• /
• v.15 no.24
• /
• pp.10659-10663
• /
• 2015

Background: Rapamycin is an effective anti-angiogenic drug. However, the mode of its action remains unclear. Therefore, in this study, we aimed to elucidate the antitumor mechanism of rapamycin, hypothetically via apoptotic promotion, using MCF-7 breast cancer cells. Materials and Methods: MCF-7 cells were plated at a density of $1{\times}10^5$ cells/well in 6-well plates. After 24h, cells were treated with a series of concentrations of rapamycin while only adding DMEM medium with PEG for the control regiment and grown at $37^{\circ}C$, 5% $CO_2$ and 95% air for 72h. Trypan blue was used to determine the cell viability and proliferation. Untreated and rapamycin-treated MCF-7 cells were also examined for morphological changes with an inverted-phase contrast microscope. Alteration in cell morphology was ascertained, along with a stage in the cell cycle and proliferation. In addition, cytotoxicity testing was performed using normal mouse breast mammary pads. Results: Our results clearly showed that rapamycin exhibited inhibitory activity on MCF-7 cell lines. The $IC_{50}$ value of rapamycin on the MCF-7 cells was determined as $0.4{\mu}g/ml$ (p<0.05). Direct observation by inverted microscopy demonstrated that the MCF-7 cells treated with rapamycin showed characteristic features of apoptosis including cell shrinkage, vascularization and autophagy. Cells underwent early apoptosis up to 24% after 72h. Analysis of the cell cycle showed an increase in the G0G1 phase cell population and a corresponding decrease in the S and G2M phase populations, from 81.5% to 91.3% and 17.3% to 7.9%, respectively. Conclusions: This study demonstrated that rapamycin may potentially act as an anti-cancer agent via the inhibition of growth with some morphological changes of the MCF-7 cancer cells, arrest cell cycle progression at G0/G1 phase and induction of apoptosis in late stage of apoptosis. Further studies are needed to further characterize the mode of action of rapamycin as an anti-cancer agent.

• Molecules and Cells
• /
• v.38 no.11
• /
• pp.966-974
• /
• 2015

Despite the presence of toll like receptor (TLR) expression in conventional $TCR{\alpha}{\beta}$ T cells, the direct role of TLR signaling via myeloid differentiation factor 88 (MyD88) within T lymphocytes on graft-versus-host disease (GVHD) and graft-versus-leukemia (GVL) effect after allogeneic stem cell transplantation (allo-SCT) remains unknown. In the allo-SCT model of C57BL/6 ($H-2^b$) ${\rightarrow}$ B6D2F1 ($H-2^{b/d}$), recipients received transplants of wild type (WT) T-cell-depleted (TCD) bone marrow (BM) and splenic T cells from either WT or MyD88 deficient (MyD88KO) donors. Host-type ($H-2^d$) P815 mastocytoma or L1210 leukemia cells were injected either subcutaneously or intravenously to generate a GVHD/GVL model. Allogeneic recipients of MyD88KO T cells demonstrated a greater tumor growth without attenuation of GVHD severity. Moreover, GVHD-induced GVL effect, caused by increasing the conditioning intensity was also not observed in the recipients of MyD88KO T cells. In vitro, the absence of MyD88 in T cells resulted in defective cytolytic activity to tumor targets with reduced ability to produce IFN-${\gamma}$ or granzyme B, which are known to critical for the GVL effect. However, donor T cell expansion with effector and memory T-cell differentiation were more enhanced in GVHD hosts of MyD88KO T cells. Recipients of MyD88KO T cells experienced greater expansion of Foxp3- and IL4-expressing T cells with reduced INF-${\gamma}$ producing T cells in the spleen and tumor-draining lymph nodes early after transplantation. Taken together, these results highlight a differential role for MyD88 deficiency on donor T-cells, with decreased GVL effect without attenuation of the GVHD severity after experimental allo-SCT.

• Proceedings of the KSR Conference
• /
• 2007.05a
• /
• pp.786-791
• /
• 2007

Korean high speed train(HSR-350x) has adopted a combined electrical and mechanical(friction) braking system. Brake blending control unit(BBCU) controls each brake system to fulfill the required brake performances such as braking distance, deceleration and jerk. Also the braking system should be designed considering the economical management, such as effective use of generated braking energy and the minimum wear of friction materials(a pad and a brake shoe). In this paper, we establish the disc braking force pattern that reduces the wear of pad in the disc braking system by minimizing the variance of the instantaneous disk baking energy during braking time, and compare the wear mass of pad between the conventional disc braking force pattern and the established results.

• Journal of Sensor Science and Technology
• /
• v.2 no.1
• /
• pp.109-115
• /
• 1993

A CdS single crystal was grown by using sublimation method. Lattice constants, $a_{o}$ and $c_{o}$, obtained by using extrapolation were $4.131{\underline{8}}{\AA}$ and $6.712{\underline{2}}{\AA}$, respectively. The carrier density was${\sim}10^{23}m^{-3}$ and the mobility was $2.93{\times}10^{-2}m^{2}$/V sec from measured Hall data at room temperature. The mobility has a increasing tendency in proportion to $T^{1/2}$ from 33 K to 150 K and a decreasing tendency in proportion to $T^{-2}$ from 180 K to room temperature. The short wavelength band peak measured from photocurrent was due to intrinsic transition, and the energy value of this peak was equal to the energy band gap of CdS photoconductor.