• Journal of Life Science
• /
• v.28 no.7
• /
• pp.778-785
• /
• 2018

Autophagy is a complex signaling process and has been implicated in tumor suppression and anticancer therapy resistance. Autophagy can produce tumor-suppressive effect by inducing autophagic cell death, either in collaboration with apoptosis. In this current study, we found that celecoxib (CCB), a nonsteroidal anti-inflammatory drug (NSAID) with multifaceted effects, induced autophagy including enhanced LC3 conversion (LC3-I to LC3-II) and reduced autophagy substrate protein p62 level in multidrug-resistant (MDR) cancer cells. CCB sensitized human multidrug resistant (MDR) cancer cells to the ansamycin-based HSP90 inhibitor 17-allylamino-17-demethoxygeldanamycin (17-AAG), a benzoquinoid ansamycin, which causes the degradation of several oncogenic and signaling proteins, by inducing autophagic cell death and apoptosis. CCB significantly augmented 17-AAG-mediated level of LC3-II/LC-I, indicating the combined effect of 17-AAG and CCB on the induction of autophagy. Autophagic degradation of mutant p53 (mutp53) and activation of caspase-3 in 17-AAG-treated MDR cells were accelerated by CCB. Inhibition of caspase-3-mediated apoptotic pathway by Z-DEVD-FMK, a caspase-3 inhibitor, did not completely block CCB-induced cell death in MCF7-MDR cells. In addition, treatment of MDR cells with Z-DEVD-FMK failed to prevent activation of autophagy by combined treatment with 17-AAG and CCB. Based on our findings, the ability of clinically used drug CCB to induce autophagy has important implications for its development as a sensitizing agent in combination with Hsp90 inhibitor of MDR cancer.

• 한국생물공학회:학술대회논문집
• /
• 2000.04a
• /
• pp.53-56
• /
• 2000

Two-stage fed-batch culture was peformed to improve the volumetric productivity of erythritol. In the growth phase dissolved oxygen was maintained to 20% and the feed medium was automatically supplied to the fermenter by pH-stat mode. The cell yield was 0.76 g-cell/g-glucose. In two-stage fed-batch culture, 41% of total erythritol conversion yield with 187 g/L of erythritol concentration and 2.79 g/L-h of maximum erythritol Productivity were obtained when 400 g/L of glucose was directly added in the form of non-sterile powder at production phase. The erythritol productivity increased in parallel with cell mass. The metabolic shift in the biosynthetic pathway of erythritol was caused by dissolved oxygen concentration. The production of gluconic acid was observed when the dissolved oxygen in the medium was maintained over 40% during the production phase, whereas the dissolved oxygen concentration lower than 40% caused the production of citric acid. But the butyric acid was produced independently with dissolved oxygen concentration in the medium. The production of organic acids such as gluconic acid, citric acid, and butyric acid was decreased by addition of mineral salts.

• Science of Emotion and Sensibility
• /
• v.23 no.3
• /
• pp.47-62
• /
• 2020

The snake detection theory posits that, due to competition with snakes, the primate visual system has been evolved to detect camouflaged snakes. Specifically, one of its hypotheses states that the subcortical visual pathway mainly consisting of koniocellular cells enables humans to automatically detect the threat of snakes without consuming mental resources. Here we tested the hypothesis by comparing human participants' responses to snakes with those to fearful faces and flowers. Participants viewed either original images or converted ones, which lacked the differences in color, luminance, contrast, and spatial frequency energies between categories. While participants in Experiment 1 produced valence and arousal ratings to each image, those in Experiment 2 detected target images in the breaking continuous flash suppression (bCFS) paradigm. As a result, visual factors influenced the responses to snakes most strongly. After minimizing visual differences, snakes were rated as being less negative and less arousing, and detected more slowly from suppression. In contrast, the images of the other categories were less affected by image conversion. In particular, fearful faces were rated as greater threats and detected more quickly than other categories. In addition, for snakes, changes in arousal ratings and those in bCFS response times were negatively correlated: Those snake images, the arousal ratings of which decreased, produced increased detection latency. These findings suggest that the influence of snakes on human responses to threat is limited relative to fearful faces, and that detection responses in bCFS share common processing mechanisms with conscious ratings. In conclusion, the current study calls into question the assumption that snake detection in humans is a product of unconscious subcortical visual processing.

• Applied Biological Chemistry
• /
• v.9
• /
• pp.1-7
• /
• 1968

The action Spectra for violaxanthin de-epoxidation and zeaxanthin expoxidation in New Zealand spinach leaf segments Tetragonia expansa, were determined at equal incident quanta of $2.0{\times}10^{15}$ quanta $cm^{-2}$ $second^{-1}$. The action spectrum for de-epoxidation had major peaks at approximately 180 and 648 nm. Blue light was slightly more effective than red light and little activity was observed beyond 700 nm. The action spectrum for epoxidation showed major peaks at around 441 and 670 nm. Blue light was more effective than red light and light beyond 700 nm showed definite activity. The net result of de-epoxidation and epoxidation is a cyclic scheme, the violaxanthin cycle, which consumes $O_2$ and photoproducts. The action spectra indicate that the violaxanthin cycle is more active m clue than in red light and therefore could accout for $O_2$ uptake stimulated by blue light. The differences between the action spectra for de-epoxidation suggest that possibly two photosynthetic systems are involved. It was suggested that the violaxanthin cycle may functional a pathway for the consumption of excess photoproducts generated in blue light or the conversion of these photoproducts to other forms of energy.

• Journal of Ecology and Environment
• /
• v.44 no.3
• /
• pp.126-142
• /
• 2020

Background: Most of the Pinus densiflora forests, occupying the largest area, have been restored in South Korea since the 1970s. As young pioneer forests, the succession process is under way. Since the forests are distributed nationwide and are vulnerable to disturbances, the process may differ depending on the geography and/or site conditions. Therefore, we reviewed the direction, the seral communities, and the late-successional species of progressive and disturbance-driven succession nationwide in the cool-temperate zone through meta-analysis and empirical observations. Main text: As a result of a meta-analysis of the direct succession and vertical structure, we found that the P. densiflora forest is in a directionally progressive succession, changing to the broadleaved forest after forming a mixed forest with its overwhelming successor, Quercus species (particularly Q. mongolica and Q. serrata). In dry stands in a relative sense, the Quercus species was favored occupying over 80% of the abundance of the succeeding species. Therefore, in dry stands, it is presumed that Quercus-dominated stage would last for a long time due to the current dominance and long life span, and eventually, it settles as Quercus-broadleaved forest with a site change. Contrary to this, it is presumed that in mesic stands where Quercus species do not occur or have low abundance, the late-successional broadleaved species settle early to form a co-dominant forest with multiple species. Due to geographical limits, the species composition of the two late-successional forests is different. Disturbances such as insect pests and fire retrogressed vulnerable P. densiflora forest for a while. However, it was mostly restored to the Quercus forest and is expected to be incorporated in the pathway of the dry stand. Conclusions: We revealed the succession process of P. densiflora forests according to geography and moisture and found that stand moisture had a decisive effect on the species and abundance of the successor. Although the P. densiflora forest is undergoing structural changes, the forest is still young; so within a few decades, physiognomy is not likely to change. Therefore, the decrease in the forest area may be due to other causes such as disturbances and forest conversion rather than due to succession.

• Journal of the Korea Organic Resources Recycling Association
• /
• v.28 no.1
• /
• pp.65-72
• /
• 2020

The aims of this study were to compare the biomethanation of CO₂ through specific methanogenic activity (SMA) test which was inoculated with four different types of mixed microbial culture obtained from full-scale anaerobic digestion (AD) plants. The experimental results showed that CH₄ conversion was the highest in the samples inoculated by seed sludge taken from ADs of food waste and brewery; under this condition, the produced biomethane contains 89.3-91.9% of CH₄. Meanwhile, the lowest level was obtained in the sample from sewage sludge. The measured ratio of CH₄ production rate to CO₂ consumption rate in all reactors was higher than the theoretical value (1) in the middle of the period and soon dropped to 0.7-0.8. It might be due to changed metabolic pathways in the reactor by the degradation of residual organic matter and the increased activity of homoacetogenic bacteria.

• Molecules and Cells
• /
• v.26 no.6
• /
• pp.536-547
• /
• 2008

Anthocyanidin synthase (ANS, leucoanthocyanidin oxygenase), a 2-oxoglutarate iron-dependent oxygenase, catalyzed the penultimate step in the biosynthesis of the anthocyanin class of flavonoids, from the colorless leucoanthocyanidins to the colored anthocyanidins. The full-length cDNA and genomic DNA sequences of ANS gene (designated as GbANS) were isolated from Ginkgo biloba for the first time. The full-length cDNA of GbANS contained a 1062-bp open reading frame (ORF) encoding a 354-amino-acid protein. The genomic DNA analysis showed that GbANS gene had three exons and two introns. The deduced GbANS protein showed high identities to other plant ANSs. The conserved amino acids (H-X-D) ligating ferrous iron and residues (R-X-S) participating in 2-oxoglutarate binding were found in GbANS at the similar positions like other ANSs. Southern blot analysis indicated that GbANS belonged to a multi-gene family. The expression analysis by real-time PCR showed that GbANS expressed in a tissue-specific manner in G. biloba. GbANS was also found to be up-regulated by all of the six tested abiotic stresses, UV-B, abscisic acid, sucrose, salicylic acid, cold and ethylene, consistent with the promoter region analysis of GbANS. The recombinant protein was successfully expressed in E. coli strain with pET-28a vector. The in vitro enzyme activity assay by HPLC indicated that recombinant GbANS protein could catalyze the formation the cyanidin from leucocyanidin and conversion of dihydroquercetin to quercetin, suggesting GbANS is a bifunctional enzyme within the anthocyanidin and flavonol biosynthetic pathway.

• Development and Reproduction
• /
• v.10 no.2
• /
• pp.127-133
• /
• 2006

[ $17\;{\alpha}-hydroxylase/17,20-lyase(P450_{C17})$ ] is the key enzyme mediating the conversion of progesterone to $17\;{\alpha}-hydroxyprogesterone$, ultimately to androstenedione during steroidogenesis. R. dybowskii's ovarian $P450_{C17}$ cDNA was cloned to understand the regulatory mechanism of ovarian steroidogenic pathway at the molecular level in amphibian. A 2.5kb cDNA clone encoding a single open-reading frame with a 519 deduced amino acid was isolated with the screening of ovarian cDNA library. This sequence contained the three highly conserved domains as seen in $P450_{C17}$ of other species. The comparison of amino acid sequence of Rana $P450_{C17}$ with other animal's $P450_{C17}$ showed relatively high identity with 76% in Xenopus, 63% in chicken, 60% in rainbow trout, and 45% in human. Phylogenic analysis also indicated that Rana $P450_{C17}$ gene was evolutionary well conserved among vertebrate. Northern analysis indicated that the two different sizes of $P450_{C17}$ transcripts with approximately 2.5 and 3.6kb were detected in ovary tissue, but not in other tissues. The expression vector of Rana $P450_{C17}$ clearly showed the $17\;{\alpha}-hydroxylase$ activity converting the exogenous progesterone into $17\;{\alpha}-hydroxyprogesterone$ in the nonsteroidogenic COS-1 cells. Therefore, Rana $P450_{C17}$ cDNA is very useful to investigate the molecular mechanism of the ovarian steroidogenesis in amphibian.

• Journal of Gastric Cancer
• /
• v.17 no.3
• /
• pp.228-236
• /
• 2017

Purpose: Enolase is a cytoplasmic enzyme that catalyzes the conversion of 2-phosphoglycerate to phosphoenolpyruvate in the glycolytic pathway. The aim of this study was to investigate whether the overexpression of neuron-specific enolase (NSE) can serve as a prognostic factor in patients with gastric cancer (GC). Materials and Methods: To assess its prognostic value in GC, NSE expression was measured by immunohistochemistry in a clinically annotated tissue microarray comprising of 327 human GC specimens. Cytoplasmic NSE expression was scored from 0 to 4, reflecting the percentage of NSE-positive cells. Results: In terms of histology as per the World Health Organization criteria (P=0.34), there were no differences between the NSE overexpression (NSE-OE) and NSE underexpression (NSE-UE) groups. The NSE-OE group showed a significantly lower rate of advanced GC (P<0.01), lymph node metastasis (P=0.01), advanced stage group (P<0.01), cancer-related death (P<0.01), and cancer recurrence (P<0.01). Additionally, a Kaplan-Meier survival analysis revealed that the NSE-OE group had longer cumulative survival times than the NSE-UE group (log-rank test, P<0.01). However, there were no significant differences in the serum levels of NSE expression in patients with GC and healthy volunteers (P=0.28). Conclusions: Patients with NSE overexpressing GC tissues showed better prognostic results, implying that NSE could be a candidate biomarker of GC.

• Journal of Radiation Protection and Research
• /
• v.33 no.2
• /
• pp.67-76
• /
• 2008

As the first comprehensive attempt at a national implementation, this study aims at assessing the external costs of major electricity generation technologies in Korea, particularly an evaluation of the impacts on human health resulting from exposures to atmospheric radiological emissions from nuclear power plants, and a monetary quantification of their damages. The methodology used for the assessment of the externalities of the selected fuel cycles has been developed by the International Atomic Energy Agency (IAEA), namely the SimPacts Model Package. The model is internationally recognized as a tool which can be applied to a wide range of fuels, different technologies and locations, for an externalities study. In this study, the relevant emissions are quantified first and then their impacts on human health are evaluated and compared. The study focused on all the nuclear power plants for the last 6 years ($2001{\sim}2006$) in Korea. With respect to nuclear power, the impact analysis only focuses on a power generation, however the front- and back-end nuclear fuel cycles are not included, namely uranium mining, conversion, enrichment, reprocessing, conditioning, etc., because these facilities are not present in Korea. The analysis results show that nuclear power in general, generates low external costs. The highest damage costs from the nuclear power plants among the 4 sites in Korea were estimated to be 3.9 mills/MWh, which is about 1/20th of the result for a similar case study conducted in the U.K., implemented through the ExternE project. This difference is largely due to the number of radionuclides included in the study and the amount of released radioactive emissions based on up-to-date information in Korea. In this study, the sensitivities of the major factors for nuclear power plants were also calculated. The analysis indicates that there was around a ${\pm}3%$ damage costs variation to a ${\pm}15%$ change of the reference population density and a ${\pm}1%$ damage cost variation to a $1{\sim}30$ meters change of the effective release height, respectively. These sensitive calculations show that there is only a minor difference when the reference costs are compared.