• Korean Journal of Environmental Agriculture
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• v.29 no.3
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• pp.293-299
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• 2010

The aim of this study was to investigate the possible impact of Bt Chinese cabbage on the soil microbial community. Microbial communities were isolated from the rhizosphere of one Bt Chinese cabbage variety and four varieties of conventional ones and were subjected to be analyzed using both culture-dependent and molecular methods. The total counts of bacteria, fungi, and actinomycetes in the rhizosphere of transgenic and conventional Chinese cabbages were observed to have an insignificant difference. Denaturing gradient gel electrophoresis (DGGE) analysis of PCR-amplified 16S rRNA genes revealed that the bacterial community structures were very similar to each other and this genetic stability of microbial communities was maintained throughout the culture periods. Analysis of dominant isolates in the rhizosphere of transgenic and conventional Chinese cabbages showed that the dominant isolates from the soil of transgenic Chinese cabbage belonged to the Bacilli and Alphaproteobacteria, while the dominant isolates from the soil of conventional cabbage belonged to the Holophagae and Planctomycetacia, respectively. These results indicate that the Bt transgenic cabbage has no significant impact on the soil microbial communities.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.60 no.4
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• pp.401-411
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• 2015

Drought stress has detrimental effects on the seedling development, vegetative/ reproductive growth, photosynthesis, root proliferation, anthesis, anthesis-silking interval (ASI), pollination and grain yield in maize. Typically, two weeks before silking through pollination are an important time in maize life. Here we reviewed the effects of drought stress on growth, physiological/ molecular researches for drought tolerance, and breeding to genomics in maize. Drought stress during kernel development increases leaf dying and lodging, decreases grain filling period and grain yield. Physiological factors of drought stress/ effects are water content, water deficits, and water potential. Nowdays molecular marker assisted breeding method is becoming increasingly useful in the improvement of new germplasm with drought stress tolerance.

• Korean Journal of Ecology and Environment
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• v.50 no.3
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• pp.305-313
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• 2017

We investigate that the impact of freshwater organism exposed to the salinity environment by the frequent rainfall following climate change. To evaluate the stress response following salinity exposure, we assessed the survival rate, molting success rate, the developmental period and mouthpart deformities in Chironomus riparius. In addition, we measured the molecular responses of biomarker gene, gene expression of heat shock protein 70 (HSP70) in C. riparius exposed to salinity after 96 hour. The C. riparius survival rates were showed on time dependent manner and not observed survival organisms above 15 psu at day 4. The pupation and emergence of C. riparius were not seen above 15 psu, and the molting success rate was less than 20% at 10 psu. The developmental retardation of C. riparius was well observed in the pupation and emergence period and was delayed by 4 days at 10 psu compared to the control and 5 psu. The mouthpart deformities after salinity exposure at 96 or 72 hour were observed at 10 psu and 15 psu. The expression of C. riparius HSP70 level was significantly increased exposure to 5 psu and 10 psu. Thus, salinity has been caused to be various ecotoxicological and molecular stress responses on freshwater organisms similar to harmful substances such as EDCs and so on.

• Korean Journal of Environment and Ecology
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• v.26 no.4
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• pp.475-483
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• 2012

Tribolodon hakonensis(Cypriniformes; Leuciscinae) is anadromous; they are born in freshwater, migrate back to the ocean, then return to their home stream for spawning from mid-March to early-June. Here, five microsatellites were used to assess the level of gene flow among T. hakonensis populations from the Samcheok-Oship Stream, South Korea. The frequencies of dominant alleles across several loci differed between down-and upstream populations divided by several weirs, and pairwise multilocus $F_{ST}$ estimate was significantly high(0.083). However, there were no signs of any loss of genetic variation in the upstream population. Assignment tests of individuals in admixture model(K=2) to a set of baseline samples showed fairly correct assignment to each cluster; all of upstream individuals sere included in the first cluster, while the majority of downstream individuals(65%) comprise the second cluster. These results indicate reduced gene flow between up- and downstream populations but allowing passive downstream drift. It is likely that man-made structures might at least partially be a factor for creating and consolidating the current distribution patterns of genetic variation among T. hakonensis populations in the Samcheok-Oship Stream. This information will assist governing agencies in making informed decisions regarding conservation of anadromous fishes in Korean drainage systems.

• Journal of Life Science
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• v.22 no.9
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• pp.1173-1179
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• 2012

The importance of genetic stability and bio-safety in the environment has recently been recognized for many (genetically modified) GM plants. This study evaluated the GM safety of transgenic rice and its environmental variance. Data on agronomic characters and principal component were collected for vitamin A-enriched GM rice and four check cultivars in a large GM field trial during 2009-2011. The cultivation environment was a large GM field and a greenhouse. In this experiment, there was no significant difference between the agronomic characters of the GM rice and those of a donor plant, 'Nagdong'. In terms of grain characteristics, the appearance and physicochemical characteristics of the GM rice and those of the donor plant were similar. However, the grain of the GM rice developed a white core and a white belly when planted in the greenhouse. The type and distribution of dominant weed species were not different in the GM rice and the 'Nagdong'. In addition, gene flow was not detected in the dominant weed species based on PCR analysis.

• Korean Journal of Environmental Agriculture
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• v.30 no.4
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• pp.466-472
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• 2011

BACKGROUND: Soybean [Glycine max (L.) Merrill] is a legume and an important oil crop worldwide. This study was conducted to evaluate the possible impact of transgenic soybean cultivation on the soil microbial community. METHODS AND RESULTS: Microorganisms were isolated from the rhizosphere soils. Microbial community was identified based on the culture-dependent and molecular biology methods. The total numbers of bacteria, fungi, and actinomycete in the rhizosphere soils cultivated with transgenic and non-transgenic soybeans were similar to each other, and there was no significant difference between transgenic and non-transgenic soybeans. Dominant bacterial phyla in the rhizosphere soils cultivated with transgenic or non-transgenic soybeans were Actinobacteria, Firmicutes, and Proteobacteria. The microbial communities in transgenic and non-transgenic soybean soils were characterized using the denaturing gradient gel electrophoresis (DGGE). The DGGE profiles showed the different patterns, but didn't show significant difference to each other at 0.05 significance level. DNAs were isolated from soils cultivating transgenic or non-transgenic soybeans and analyzed for persistence of transgenes in the soil by using PCR. PCR analysis revealed that there were no amplified ${\gamma}$-tmt and bar gene in soil DNA. CONCLUSION(S): The results of this study suggested that microbial community of soybean field were not significantly affected by cultivation of the transgenic soybeans.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.2
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• pp.377-386
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• 2021

The A60 class deck penetration piece is a fire-resistant system installed on a horizontal compartment to prevent flame spreading and protect lives in fire accidents in ships and offshore plants. This study deals with approximate optimization using discrete variables for the fire resistance design of an A60 class deck penetration piece using different surrogate models and a genetic algorithm. Transient heat transfer analysis was performed to evaluate the fire resistance design of the A60 class deck penetration piece. For the approximate optimization of the piece, the length, diameter, material type, and insulation density were applied to discrete design variables, and temperature, productivity, and cost constraints were considered. The approximate optimum design problem based on the surrogate models was formulated such that the discrete design variables were determined by minimizing the weight of the piece subjected to the constraints. The surrogate models used in the approximate optimization were the response surface model, Kriging model, and radial basis function-based neural network. The approximate optimization results were compared with the actual analysis results in terms of approximate accuracy. The radial basis function-based neural network showed the most accurate optimum design results for the fire resistance design of the A60 class deck penetration piece.

• Korean Journal of Environmental Biology
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• v.37 no.1
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• pp.72-81
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• 2019

Bisphenol A (BPA), a representative endocrine disrupting chemicals, has adverse effects on growth, development and reproduction in aquatic organisms. The object of this study was to investigate the modulation of antioxidant enzyme-coding genes using quantitative real time RT-PCR (qRT-PCR), enzyme activity and total protein content, to understand oxidative stress responses after exposure to BPA for 48 h in brackish water flea Diaphanosoma celebensis. The BPA ($3mg\;L^{-1}$) significantly upregulated the expression of Cu/Zn-SOD, Mn-SOD, and catalase (CAT) mRNA. Three GST isoforms (GST-kappa, GST-mu, and GST-theta) mRNA levels significantly increased at the rate of $0.12mg\;L^{-1}$ of BPA. In particular, GST-mu showed the highest expression level, indicating its key role in antioxidant response to BPA. SOD activity was induced with a concentration-dependent manner, and total protein contents was reduced. These findings indicate that BPA can induce oxidative stress in this species, and these antioxidants may be involved in cellular protection against BPA exposure. This study will provide a better understanding of molecular mode of action of BPA toxicity in aquatic organisms.

• Journal of Life Science
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• v.34 no.7
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• pp.520-530
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• 2024

Tumor suppressor genes (TSGs) play a crucial role in maintaining cellular homeostasis. When the function of these genes is lost, it can lead to cellular plasticity that drives the development of various cancers, including small-cell lung cancer (SCLC), which is known for its aggressive nature. SCLC is primarily driven by numerous loss-of-function mutations in TSGs, often involving genes that encode epigenetic regulators. These mutations pose a significant therapeutic challenge as they are not directly targetable. However, understanding the molecular changes resulting from these mutations might provide insights for developing tumor intervention strategies. We propose that despite the heterogeneous genomic landscape of SCLC, the effects of mutations in patient tumors converge on a few critical pathways that drive malignancy. Specifically, alterations in epigenetic regulators lead to transcriptional dysregulation, pushing mutant cells toward a highly plastic state that makes them immune evasive and highly metastatic. This review will highlight studies showing how an imbalance of epigenetic regulators with opposing functions leads to the loss of immune recognition markers, effectively hiding tumor cells from the immune system. Additionally, we will discuss the role of epigenetic regulators in maintaining neuroendocrine features and how aberrant transcriptional control promotes epithelial-to-mesenchymal transition during tumor development. Although these pathways seem distinct, we emphasize that they often share common molecular drivers and mediators. Understanding the connection among frequently altered epigenetic regulators will provide valuable insights into the molecular mechanisms underlying SCLC development, potentially revealing preventive and therapeutic vulnerabilities for SCLC and other cancers with similar mutations.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.6 no.4
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• pp.265-273
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• 2001

The sea urchin has been used as sea food in many countries. This species has also been an important organism of embryological studies for more than a century. In recent years, sea urchin embryos are being used as testing materials for toxicity of pollutants and toxins. Usefulness of sea urchin embryos as experimental models comes from the easiness in obtaining sea urchin samples and a lot of gametes, in rearing embryos in the laboratory, in observing the cellular movement and organ formation during the embryogenesis and in manipulating blastomeres and genetic maferials. The sea urchin in itself is a key organism for the understanding of deuterostome evolution from the protostomes and of indirect development of marine invertebrates which undergo the planktotrophic larval stage. A fertilized sea urchin egg goes through rapid cleavage and becomes a 60 cell embryo 7hr after fertilization. It then develops into a morula, a blastula, a gastrula and finally a pluteus larva approximately 70 hr after fertilization. At the 60 cell stage, the embryo comprises of five territories that express territory-speciflc genes and later form different organs. Micromeres at the vegetal pole ingress into the blastoceol and become the primary mesenchyme cells(PMCs). PMCs express genes involved in skeletogenesis such as SM30, SM37, SM50, PM27, msp130. Among the genes, SM37 and SM50 are considered to be members of a gene family which is characterized by early blastula expression, Glycine-Proline-Glutamine rich repeat structures and spicule matrix forming basic proteins. Genetic studies on the sea urchin embryos help understand the molecular basis of indirect development of marine invertebrates and also of the biomineralization common to the animal kingdom.