• Journal of Life Science
• /
• v.22 no.8
• /
• pp.999-1008
• /
• 2012

The circadian clock is a self-sustaining 24-hour timekeeper that allows organisms to anticipate daily-changing environmental time cues. Circadian clock genes are regulated by a transcriptional-translational feedback loop. In Arabidopsis, LATE ELONGATED HYPOCOTYL (LHY) and CIRCADIAN CLOCK-ASSOCIATED 1 (CCA1) transcripts are highly expressed in the morning. Translated LHY and CCA1 proteins repress the expression of the TIMING OF CAB EXPRESSION 1 (TOC1) transcripts, which peaks in the evening. The TOC1 protein elevates the expression of the LHY and CCA1 transcripts, forming a negative feedback loop that is believed to constitute the oscillatory mechanism of the clock. In mammals, the transcription factor protein CLOCK, which is a central component of the circadian clock, was reported to have an intrinsic histone acetyltransferase (HAT) activity, suggesting that histone acetylation is important for core clock mechanisms. However, little is known about the components necessary for the histone acetylation of the Arabidopsis clock-related genes. Here, I report that DET1 (De-Etiolated1) functions as a negative regulator of a key component of the Arabidopsis circadian clock gene LHY in constant dark phases (DD) and is required for the down-regulation of LHY expression through the acetylation of histone 3 (H3Ac). However, the HATs directly responsible for the acetylation of H3 within LHY chromatin need to be identified, and a link connecting the HATs and DET1 protein is still absent.

• Journal of the Korean Data and Information Science Society
• /
• v.28 no.6
• /
• pp.1427-1435
• /
• 2017

The smart farm is a remarkable system because it utilizes information and communication technologies in agriculture to bring high productivity and excellent qualities of crops. It automatically measures the growth environment of the crops and accumulates huge amounts of environmental information in real time growing in smart farms using multi-variable control of environmental factors. The statistical model using the collected big data will be helpful for decision making in order to control optimal growth environment of crops in smart farms. Using data collected from a smart farm of tomato, we carried out multiple regression analysis to determine the relationship between yield and environmental factors and to predict yield of tomato. In this study, appropriate parameter modification was made for environmental factors considering tomato growth. Using these new factors, we fit the model and derived the optimal environmental factors that affect the yields of tomato. Based on this, we could predict the yields of tomato. It is expected that growth environment can be controlled to improve tomato productivities by using statistical model.

• Korean Journal of Environmental Biology
• /
• v.27 no.1
• /
• pp.58-65
• /
• 2009

The chemopreventive effects of naringenin derived from citrus on tumor migration and the possible mechanisms involved in this protection were investigated in HT-1080 tumor cells. In this study, we found that naringenin reduced phorbol 12-myristate 13-acetate (PMA)-enhanced matrix metalloproteinases (MMP)-9 activation in a dose-dependant manner and further inhibited HT-1080 cell migration. In addition, naringenin suppressed PMA-enhanced expression of MMP-9 protein, mRNA and transcription activity levels through suppression of nuclear factor $\kappa$B (NF-$\kappa$B) activation and activator protein-1 (AP-1) translocation without changing tissue inhibitor of metalloproteinase (TIMP)-1 level. Therefore, our results suggested that the inhibitory effects of naringenin on MMP-9 activation, relation of tumor migration in vitro possibly involve mechanisms related to its ability to suppress PMA-enhanced MMP-9 gene and protein expression through NF-$\kappa$B activation and AP-1 translocation. Overall, naringenin may be a valuable anti-invasive drug candidate for cancer therapy.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 2003.09a
• /
• pp.318-321
• /
• 2003

비소로 오염된 토양, 하천 퇴적물 및 광미의 복원할 때, 토양 세척 공정에서 중요한 인자인 비소의 화학적 결합형태와 세척제에 따른 용출특성과 고효율 세척 및 세척액의 재활용도를 높이기 위한 공정을 바탕으로 토양세척장비를 설계하였다. 화학적 결합형태에 있어서 토양은 잔류 결합형태가 주되고, 퇴적물의 경우는 철산화물과의 결합형태가 강하며, 광미는 황화물과의 결합에 따른 잔류형태와 철산화물과의 결합형태가 상당부분을 차지한다. 세척제에 따른 용출특성으로부터, 철산화물과 황화물과 결합하고 있는 비소의 화학적 결합형태를 파괴하면서 비소를 추출할 수 있는 용제로 HCl, Oxalate, EDTA, M$_2$O$_2$를 사용하였다. 추출 결과, 비소가 철산화물과 결합한 형태가 비중이 높을수록 EDTA 나 Oxalate가 효율이 높으며, 황화물에 대해서는 HCl과 $H_2O$$_2$이 상대적으로 높은 추출 효율을 보였다. 구성된 세척조는 밀폐실린더형과 스크류이송형 세척조로 구성되어 각각 혼합교반에 의한 세척과 토양입자 분급에 따른 세척이 가능하다. 세척 공정중 최적 산도 조절이 중요한 인자가 되며, 세척액의 재활용도를 높일때, 세척수에 용해되어 있는 비소 및 중금속과 미립자의 동시 제거를 위한 응집 침전조에서 응집제에 의해서 미립자와 함께 제거하는 응집, 침전 및 분리공정을 배치하였다.

• Korean Journal of Clinical Laboratory Science
• /
• v.47 no.4
• /
• pp.298-305
• /
• 2015

Stem cell-like tumor cells are reported to be the main reason for tumor recurrence and metastasis. As one of the new approaches to overcome cancer, studies are emerging to inhibit the expressions of stem cell transcriptional factors (Oct4, Sox2, Klf-4, and Lin28) in cancer cells. MicroRNAs are master genetic regulators that can control development and differentiation of stem cells. In this study using various ovarian tumors (Skov3, Ovcar3, Tov112D, Tov21G, PA-1 and Hsc832(c)T), we examined the expressions of stem cell-related transcription factors, and the biological changes in cell survival and growth by miR-126 that targets stem cell transcriptional factors. We observed that treatment of miR-126 induced the morphological changes and cell suspension in most cells. In addition, miR-126 induced gradual regression of cell division except Skov3 cells, especially significant time-dependent reduction in Tov112D, Tov21G and PA-1. When we examined the expression of stem cell transcriptional factors, Sox2 was shown to be down-regulated after miR-126. Our results demonstrate that miR-126 treatment can provide the reversible environment to regulate cell division and to induce cell death of ovarian tumors, suggesting the molecular biological clues for clinical usage.

• Journal of Bio-Environment Control
• /
• v.29 no.3
• /
• pp.277-284
• /
• 2020

To increase the utilization of the intelligent methodology of smart farm management, estimation modeling techniques are required to assess prior examination of crops and environment changes in realtime. A mandatory environmental factor such as CO₂ is challenging to establish a reliable estimation model in time domain accounted for indoor agricultural facilities where various correlated variables are highly coupled. Thus, this study was conducted to develop an artificial neural network for reducing time complexity by using environmental information distributed in adjacent areas from a time perspective as input and output variables as CO₂. The environmental factors in the smart farm were continuously measured using measuring devices that integrated sensors through experiments. Modeling 1 predicted by the mean data of the experiment period and modeling 2 predicted by the day-to-day data were constructed to predict the correlation of CO₂. Modeling 2 predicted by the previous day's data learning performed better than Modeling 1 predicted by the 60-day average value. Until 30 days, most of them showed a coefficient of determination between 0.70 and 0.88, and Model 2 was about 0.05 higher. However, after 30 days, the modeling coefficients of both models showed low values below 0.50. According to the modeling approach, comparing and analyzing the values of the determinants showed that data from adjacent time zones were relatively high performance at points requiring prediction rather than a fixed neural network model.

• Food Science and Preservation
• /
• v.5 no.3
• /
• pp.231-238
• /
• 1998

The effects of temperature(0, 5, 10 $^{\circ}C$), sawdust removal in root part and packaging conditions on the respiration and keeping qualities were evaluated. Higher respiratory activity, weight loss and stipe elongation were observed at higher temperature. Removal of sawdust part slowed down the rate of stipe elongation with little effect on the respiration rates, and therefore improve the quality preservation. The modified atmosphere packaging of 100g mushroom using hermetically sealing by 30 $\mu\textrm{m}$ polypropylene (CPP) and low density polyethylene (LDPE) films were effective in preserving the quality such as visual appearance and Hunter L value, and reducing weight loss at 0$^{\circ}C$, 5$^{\circ}C$ and 10$^{\circ}C$ compared to perforated packages.

• Microbiology and Biotechnology Letters
• /
• v.44 no.4
• /
• pp.409-419
• /
• 2016

Filamentous Aspergillus spp. are the most common fungi in our environment and can be beneficial and/or pathogenic to humans. Many Aspergillus spp. reproduce by forming asexual spores and can synthesize various secondary metabolites. A series of studies has revealed that Velvet regulators are fungus-specific transcription factors coordinating fungal growth, development, and secondary metabolism in the model fungus Aspergillus nidulans. Proteins of the Velvet family form various complexes that play diverse roles in the life cycle of A. nidulans. In other Aspergillus spp., proteins of this family are highly conserved and coordinate asexual development and secondary metabolism. This review summarizes the functions of Velvet proteins in Aspergillus spp.

• Korean Journal of Ecology and Environment
• /
• v.39 no.1 s.115
• /
• pp.52-61
• /
• 2006

The aim of this study was to analyze the seasonal patterns of zooplankton community dynamics in the lower Nakdong River (Mulgum, RK; river kilometer; 27 km from the estuarine barrage), with a Self-Organizing Map (SOM) based on weekly sampled data collected over ten years(1994 ${\sim}$ 2003). It is well known that zooplankton groups had important role in the food web of freshwater ecosystems, however, less attention has been paid to this group compared with other community constituents. A non-linear patterning algorithm of the SOM was applied to discover the relationship among river environments and zooplankton community dynamics. Limnological variables (water temperature, dissolved oxygen, pH , Secchi transparency, turbidity, chlorophyll a, discharge, etc.) were taken into account to implement patterning seasonal changes of zooplankton community structures (consisting of rotifers, cladocerans and copepods). The trained SOM model allocated zooplankton on the map plane with limnological parameters. Three zooplankton groups had high similarities to one another in their changing seasonal patterns, Among the limnological variables, water temporature was highly related to the zooplankton community dynamics (especially for cladocerans). The SOM model illustrated the suppression of zooplankton due to the increased river discharge, particularly in summer. Chlorophyll a concentrations were separated from zooplankton data set on the map plane, which would intimate the herbivorous activity of dominant grazers. This study introduces the zooplankton dynamics associated with limnological parameters using a nonlinear method, and the information will be useful for managing the river ecosystem, with respect to the food web interactions.

• Korean Journal of Ecology and Environment
• /
• v.38 no.4 s.114
• /
• pp.445-453
• /
• 2005

Relative importance between bottom-up and top-down controls on phytoplankton dynamics was investigated in the Juam Reservoir, Chonnam based on the results from statistical analyses including regression and artificial neural network (ANN) modeling. Effects of nutrients on size-structured phytoplankton dynamics were explored by simple linear regression analysis and relative importance between bottom-up and top-down controls was estimated based on results from the artificial neural network analyses. Although there is a limitation in determining direct grazing effects since chlorophyll a : pheopigments ratios, indirect index for grazing activity rather than grazing rates or herbivores biomass were used, the results from regression analysis showed that nutrients especially orthophosphates were positively correlated with the phytoplankton biomass and chlorophyll a : pheopigments ratios were also positively correlated with the phytoplankton biomass at lower coefficient of determination ($r^2$) compared to orthophosphates. The simulation results from ANN suggested that the bottom-up mechanisms including water temperature and availability of nutrients, especially orthophosphates were more important than top-down mechanisms such as grazing in the phytoplankton dynamics.