• Korean Journal of Optics and Photonics
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• v.9 no.5
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• pp.333-341
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• 1998

The novel integrated device, 1.55 ${\mu}{\textrm}{m}$ DR-LD(distrbuted reflector laser diode) integrated EA-MOD (electro-absorption modulator) as light source, is proposed to improve the device yield and its operational performances. This device can be easily fabricated by the selective MOVPE technique and its fabrication processes are almost the same as the reported 1.55 ${\mu}{\textrm}{m}$ DFB-LD(distributed feedback laser diode) integrated EA-MOD except the asymmetric gratings. The static and dynamic properties are investigated simultaneously by solving the transfer matrix method for light propagation, the time-dependent rate equation for carrier change and schr$\"{o}$dinger equation for QCSE (Quantum-Confined Stark Effect). The performances of the proposed device such as output power, chirp, and extinction ratio are compared with those of DFB-LD integrated EA-MOD. Under 10Gb/s NRZ modulation, we obtain that DR-LD integrated EA-MOD. is 30% higher in output power on the on-state, about 50% lower in chirp, and slightly larger in extinction ratio than DFB-LD integrated EA-MOD.-MOD.

• Childhood Kidney Diseases
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• v.17 no.2
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• pp.79-85
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• 2013

Purpose: To test whether the expression of P-cadherin, a component of slit diaphragms between podocyte foot processes, would be altered by puromycin aminonucleoside (PAN) in a cultured podocyte in vitro. Methods: Rat glomerular epithelial cells (GEpC) were cultured with various concentrations of PAN. The distribution of P-cadherin was examined with a confocal microscope. Western blotting and reverse transcriptase-polymerase chain reaction (RT-PCR) were used to measure the change in P-cadherin expression. Results: This study found that P-cadherin was concentrated in the inner and peripheral cytoplasm with high concentrations of PAN under immunofluorescence views. Western blotting of GEpC revealed that PAN induced a decrease of P-cadherin in dose- and time-dependent manners. A high dose ($50{\mu}g/mL$) of PAN decreased P-cadherin expression by 21.9% at 24 h (P <0.05) and 31.9% at 48 h (P <0.01) compared to those without PAN. In RT-PCR, high concentrations ($50{\mu}g/mL$) of PAN also decreased P-cadherin mRNA expression, similar to protein suppression, by 23.5% at 48 h (P <0.05). Conclusion: Podocytes exposed to PAN in vitro concentrated P-cadherin internally, and reduced P-cadherin mRNA and protein expression. This could explain the development of proteinuria in experimental PAN-induced nephropathy.

• Journal of Food Hygiene and Safety
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• v.21 no.4
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• pp.269-273
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• 2006

Potassium Sorbate (PS) is a potassium salt version of sorbic acid, which has antimicrobial and fungistatic features in foods. Therefore, PS is used as a food preservative against fungi and mold. PS has been found to be non-toxic even when taken in large quantities given its trait to be broken down in the body into water and carbon dioxide. Gap Junctional Intercellular Communication (GJIC) is essential in the maintenance of tissue homeostasis during development and differentiation. This study was made of the effects of PS on GJIC in WB-F344 rat liver epithelial (WB) cells. We found dramatic decrease of cell viability in time- and dose-dependent manners when WB cells were treated with PS. The effect of PS on GJIC is strong inhibition, and it took place in parallel with a hyperphosphorylation of connexin 43 expression. The finding that PS interferes with gap junction functionality should be considered with respect to the mechanism of PS-induced hepatotoxicity.

• Journal of fish pathology
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• v.22 no.2
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• pp.97-105
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• 2009

Scuticociliates Miamiensis avidus (syn. Philasterides dicentrarchi) causes high mortality and bad growth in olive flounder Paralichthys olivaceus. Temperature is an important factor not only for growth of pathogens but also for host immune system in poikilothermal animal. In this study, temperature affecting ciliate growth and pathogenicity against olive flounder were examined. Doubling time for the ciliate growth was 61.82 hours at $5{^{\circ}C}$, 26.32 hours at $10{^{\circ}C}$, 21.14 hours at $15{^{\circ}C}$, 16.86 hours $20{^{\circ}C}$ and 16.21 hours at $25{^{\circ}C}$. Maximum ciliate numbers were similar at $10-20{^{\circ}C}$ at the range of $1.54-1.75{\times}10^{5}$/ ml. Duplicated intraperitoneal injections were conducted with the ciliates by the concentrations of $1{\times}10^{2}$, $1{\times}10^{6}$, $1{\times}10^{4}$and $1{\times}10^{5}$/ fish (average 8.34 cm, 4.33 g) then kept at $10{^{\circ}C}$, $15{^{\circ}C}$ and $20{^{\circ}C}$. Cumulative mortality was low at $10{^{\circ}C}$ and the mortality was increasing at higher water temperatures. In addition, cumulative mortality was higher at higher dose of infections. In conclusion, Scuticocilite M. avidus grew well at higher temperature (at $5{^{\circ}C}$, $10{^{\circ}C}$, $15{^{\circ}C}$ and $25{^{\circ}C}$) in vitro, and olive flounder mortality due to M. avidus was highly water temperature and dose dependent. The results of this study suggest that water temperature control may one of the essential factor to reduce mortality due to M. avidus infection.

• Korean Journal of Food Science and Technology
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• v.32 no.2
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• pp.461-468
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• 2000

To investigate the antigenotoxicity of Korean mistletoe using Comet assay, the crude extract was divided into 4 fractions, i.e. fraction I (MW range over 14,000), fraction II $(8,000{\sim}14,000)$, fraction III $(3,500{\sim}8,000)$, and fraction IV (below 3,500) by molecular weight fractionation. In the non-tumoral 3T3 cells, fraction IV could reduce DNA damage induced by MNNG in a dose dependent pattern while fraction I and III which were known to contain lectins and viscotoxins, respectively, did not show the activity. By heat treatment, the antigenotoxic activity of faction IV, though was gradually diminished according to heating time, was found to be maintained significantly. From the Sephadex G-25 gel filtration chromatography, a more purified fraction responsible for the activity of faction IV was obtained from the latter part of total elute. Therefore, it was concluded that the antigenotoxic components of Korean mistletoe were water soluble substances of MW below 1,000 and there is a possibility of utilization as a material of functional foods for chemoprevention.

• Korean Journal of Environmental Biology
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• v.35 no.4
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• pp.706-714
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• 2017

An investigation of the effects of Pb for domestic anuran embryos were evaluated with the Frog Embryo Teratogenesis Assay; Xenopus (FETAX). Depending on the species, the difference between the embryo size and the embryonic development time was determined. As a result, mortality and malformation rates were increased, malformation patterns were changed and larval body length were decreased in a dose dependent manner of the Pb. The half maximal lethal concentration ($LC_{50}$) of the Bufo gargarizans, Hyla japonica, Rana nigromaculata and Bombina orientalis were 0.58, 0.49, 0.52, $0.54mg\;L^{-1}$, respectively. The half maximal effective concentration ($EC_{50}$) of the Bufo gargarizans, Hyla japonica, Rana nigromaculata and Bombina orientalis were 0.35, 0.74, 0.30, $0.29mg\;L^{-1}$, respectively. The teratogenic index (TI) were 1.66 in the Bufo gargarizans, 1.81 in the Hyla japonica, 1.73 in the Rana nigromaculata and 1.86 in the Bombina orientalis, respectively. Therefore, the Pb seems likely to have a teratogenic effect in all four species' embryonic development. The Bombina orientalis was the most sensitive to the Pb. This means that the difference between the different species, even if they have all been exposed to the same concentration of pollutants depending on the species. The result above show that the Pb acts as a teratogenic agent in the development of the four domestic frog species.

• Nutritional Sciences
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• v.9 no.4
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• pp.233-239
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• 2006

Porous matrices of bioactive polymers such as polyglycolic acid (PGA) or polylactic acid (PLA) can be used as scaffolds in bone tissue growth during bone repair process. These polymers are highly porous and serve as a template for the growth and organization of new bone tissues. We evaluated the effect of PGA and PLA polymers on osteoblastic MC3T3-E1 cell extracellular mineralization. MC3T3-E1 cells were cultured in a time-dependent manner -1, 15, 25d as appropriate - for the period of bone formation stages in one of the five culture circumstances, such as normal osteogenic differentiation medium, PGA-plated, fetal bovine serum (FBS)-plated, PGA/FBS-coplated, and PLA-plated For the evaluation of bone formation, minerals (Ca, Mg, Mn) and alkaline phosphatase activity, a marker for osteoblast differentiation, were measured Alizarin Red staining was used for the measurement of extracellular matrix Ca deposit During the culture period, PGA-plated one was reabsorbed into the medium more easily and faster than the PLA-plated one. At day 15, at the middle stage of bone formation, cellular Ca and Mg levels showed higher tendency in PGA- or PLA-plated treatments compared to non-plated control and at day 25, at the early late stage of bone formation, all three cellular Ca, Mg or Mn levels showed higher tendency as in order of PGA-related treatments and PLA-plated treatments, compared to control even without significance. Medium Ca, Mg or Mn levels didn't show any consistent tendency. Cellular ALP activity was higher in the PGA- or PLA-plated treatments compare to normal osteogenic medium treatment PGA-plated and PGA/FBS-plated treatments showed better Ca deposits than other treatments by measurement of Alizarin Red staining, although PLA-plated treatment also showed reasonable Ca deposit. The results of the present study suggest that biodegradable material, PGA and also with less extent for PLA, can be used as a biomaterial for better extracellular matrix mineralization in osteoblastic MC3T3-E1 cells.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.32 no.4
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• pp.444-451
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• 1999

The effect of individual density on the growth and survival of Laminaria japonica was experimentally evaluated. Four density treatments of young sporophytes (0.63 cm In maximum length) grown in the laboratory were transplanted to the southeastern coast of Korea and their survivorship and growth rate were measured twice a month from January to July, 1996. Plants showed higher survivorship at low density. Final densities at three lowest densities were similar, ranging from 34 to 38 inds${\cdot}100 cm^{-2}$. Planis at the highest density, however, suffered greater decline than at lower densities, and only 21 plants remained at the end of this study. Mean frond size (length and width) fluctuated throughout the study period at four densities. During the first two mouths after outplanting, mean frond size was negatively correlated with initial density, However, the size was density independent after three months. As stand density increased, size-frequency distribution through time tended to be more positively skewed. The 10 largest plants grew faster in frond size and attained larger size in the lower density. There was a positive relationship between plant size and relative growth rate (or survival). The slope of yield-density (Y-D) relationships at four densities ranged from -0.060 to -0.137. The study suggests that density can strongly affect the survival and growth of this alga. The density-dependent survival and growth patterns, however, were not strictly consistent with those of terrestrial plants.

• Animal Bioscience
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• v.34 no.6
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• pp.957-966
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• 2021

Objective: Ovarian follicular development, which dependent on the proliferation and differentiation of granulosa cells (GCs), is a complex biological process in which miRNA plays an important role. Our previous study showed that miR-458b-5p is associated with ovarian follicular development in chicken. The detailed function and molecular mechanism of miR-458b-5p in GCs is unclear. Methods: The luciferase reporter assay was used to verify the targeting relationship between miR-458b-5p and catenin beta-1 (CTNNB1), which is an important transcriptional regulatory factor of the Wnt/β-catenin pathway. The cell counting kit-8 (CCK-8) assay, flow cytometry with propidium iodide (PI) and annexin V-fluorescein isothiocyanate (FITC) labeling were applied to explore the effect of miR-458b-5p on proliferation, cell cycle and apoptosis of chicken GCs. Quantitative real-time polymerase chain reaction and Western blot were used to detect the mRNA and protein expression levels. Results: We demonstrated that the expression of miR-458b-5p and CTNNB1 showed the opposite relationship in GCs and theca cells of hierarchical follicles. The luciferase reporter assay confirmed that CTNNB1 is the direct target of miR-458b-5p. Using CCK-8 assay and flow cytometry with PI and Annexin V-FITC labeling, we observed that transfection with the miR-458b-5p mimics significantly reduced proliferation and has no effects on apoptosis of chicken GCs. In addition, miR-458b-5p decreased the mRNA and protein expression of CD44 molecule and matrix metallopeptidase 7, which are the downstream effectors of CTNNB1 in Wnt/β-Catenin pathway and play functional roles in cell proliferation. Conclusion: Taken together, the data indicate that miR-458b-5p regulates ovarian GCs proliferation through Wnt/β-catenin signaling pathway by targeting CTNNB1, suggesting that miR-458b-5p and its target gene CTNNB1 may potentially play a role in chicken ovarian follicular development.

• Journal of Ginseng Research
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• v.43 no.2
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• pp.305-311
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• 2019

Background: Gintonin is a ginseng-derived exogenous ligand of the G protein-coupled lysophosphatidic acid (LPA) receptor. We previously reported that gintonin stimulates gliotransmitter release in primary cortical astrocytes. Astrocytes play key roles in the functions of neurovascular systems. Although vascular endothelial growth factor (VEGF) is known to influence the normal growth and maintenance of cranial blood vessels and the nervous system, there is little information about the effect of gintonin on VEGF regulation in primary astrocytes, under normal and hypoxic conditions. Methods: Using primary cortical astrocytes of mice, the effects of gintonin on the release, expression, and distribution of VEGF were examined. We further investigated whether the gintonin-mediated VEGF release protects astrocytes from hypoxia. Results: Gintonin administration stimulated the release and expression of VEGF from astrocytes in a concentration- and time-dependent manner. The gintonin-mediated increase in the release of VEGF was inhibited by the LPA1/3 receptor antagonist, Ki16425; phospholipase C inhibitor, U73122; inositol 1,4,5- triphosphate receptor antagonist, 2-APB; and intracellular $Ca^{2+}$ chelator, BAPTA. Hypoxia further stimulated astrocytic VEGF release. Gintonin treatment stimulated additional VEGF release and restored cell viability that had decreased due to hypoxia, via the VEGF receptor pathway. Altogether, the regulation of VEGF release and expression and astrocytic protection mediated by gintonin under hypoxia are achieved via the LPA receptor-VEGF signaling pathways. Conclusion: The present study shows that the gintonin-mediated regulation of VEGF in cortical astrocytes might be neuroprotective against hypoxic insults and could explain the molecular basis of the beneficial effects of ginseng on the central nervous system.