• Toxicological Research
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• v.8 no.2
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• pp.285-302
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• 1992

Human and rat hepatocytes were isolated by nonperfusion method and cultured for longer than 5 days. Human liver biopsy sample and rat liver were used as hepatocyte source. Several physical and chemical factors which were influencing on hepatocyte isolation procedure were examined and a batch isolation procedure was established for small size sample of rat liver. Isolated hepatocytes showed normal morphlologica characteristics in microscopy and electron microscopical examinations and a morphologica response to phalloidin. Isolated cells were cultured as a monolayer and proven to have intact morphological characteristics for longer than 15 days. Because human liver sample is harder and tighter compared with rat liver, a standard procedure for rat hepatocytes was slightly modified to reduce mechanical damage. Similarly with rat hepatocytes, isolated human hepatocytes showed a normal morphological characteristics and could be cultured for longer than 15days. Human and rat hepatocytes were examined on their functional integrities including cytochrome-P450 related enzyme activity and it's inducibility, hormonal inducibility of AIB uptake and TAT activity, albumin synthesis, DNA synthesis, cellular protein maintenance. In all parameters used in the present study, human and rat hepatocytes showed normal functional characteristics.

• Proceedings of the Korean Society of Toxicology Conference
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• 2001.10b
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• pp.3-4
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• 2001

Residents of Qidong, Peoples Republic of China, are at high risk for development of hepatocellular carcinoma, in part due to consumption of foods contaminated with aflatoxins. Chlorophyllin, a mixture of semi-synthetic, water-soluble derivatives of chlorophyll that is used as a food colorant and over-the-counter medicine, has been shown to be an effective inhibitor of aflatoxin hepatocarcinogenesis in animal models.(omitted)

• Proceedings of the Korean Society of Toxicology Conference
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• 2001.10a
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• pp.46-47
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• 2001

Residents of Qidong, Peoples Republic of China, are at high risk for development of hepatocellular carcinoma, in part due to consumption of foods contaminated with aflatoxins. Chlorophyllin, a mixture of semi-synthetic, water-soluble derivatives of chlorophyll that is used as a food colorant and over-the-counter medicine, has been shown to be an effective inhibitor of aflatoxin hepatocarcinogenesis in animal models.(omitted)

• Molecular & Cellular Toxicology
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• v.4 no.4
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• pp.293-299
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• 2008

To screen the differentially expressed genes in cadmuim-exposed marine medaka fish (Oryzias javanicus), a candidate marine test fish for ecological toxicity, the differential display polymerase chain reaction (DD-PCR) was carried out, since the genome-wide gene expression data are not available in this fish species yet. A total of 35 clones were isolated from cadmium-exposed fish and their nucleotide sequences were analyzed. The differentially expressed gene candidates were categorized to response to stimulus (3); ion binding (3); DNA binding (1); protein binding (6); carbohydrate binding (1); metabolic process (4); biological regulation (3); cellular process (2); protein synthesis (2); catalytic activity (2); sense of sight (1); immune (1); neurohormone (1); signaling activity (1); electron carrier activity (1) and others (3). For real-time quantitative RT-PCR, we selected catalase, glucose-6-phosphate dehydrogenase, heat shock protein 70, and metallothionein and confirmed that cadmium exposure enhanced induction of these four genes.

• Journal of The Korean Society of Grassland and Forage Science
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• v.21 no.1
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• pp.21-26
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• 2001

To develop transgenic orchardgrass resistant to reactive oxygen species produced from environmental stresses, a vector with the cytosolic glutathione reductase cDNA (BcGRl) from Chinese cabbage was constructed under the control of the cauliflower mosaic virus 35S promoter and was introduced into orchardgrass using Agrobacterium tumefaciens EHA101. Transgenic plants from hygromycin-selected calli of orchardgrass did not show any morphological difference from wild-type plants. The results of PCR amplification and genomic Southern blot analysis confirmed the integration of foreign gene into the chromosome of transgenic orchardgrass. Northern blot analysis with total RNA from leaves also confirmed the constitutive expression of BcGR1 in transgenic orchardgrass.

• Journal of Bio-Environment Control
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• v.10 no.3
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• pp.197-206
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• 2001

The depletion of stratospheric ozone is regarded as a major environmental threat to plant growth and ecosystem. The ozone depletion has caused plants to be exposed to an increased penetration of solar ultraviolet-B (UV-B) radiation in the 280-320 nm wavelength range. Enhanced UV-B radiation may have influence on plants biological functions in many aspects including inhibition of photosynthesis, DNA damage, lipid peroxidation, changes in morphology, phenology, and biomass accumulation. To cope with the damage by UV radiation, plants have evolved to have protective mechanisms, such as photorepair, accumulation of UV-absorbing compounds, leaf thickening and activation of antioxidative enzymes. The objective of this review is to address the effects of enhanced UV-B on plant growth, UV-B action mechanisms and protection and protection mechanisms in plants.

• Mycobiology
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• v.44 no.1
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• pp.21-28
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• 2016

During a Korean mushroom diversity survey from 2011 to 2014, we found one new Xylaria species (X. ripicola sp. nov.) and one Xylaria species that had not been previously observed in Korea (X. tentaculata). To confirm the phylogenetic placement of the new species, we conducted a phylogenetic investigation based on internal transcribed spacer regions of ribosomal DNA sequences. Additionally, the new species, X. ripicola, was subsequently analyzed for RNA polymerase II subunit sequences. We also evaluated the macroscopic and microscopic features of this species. Herein, X. ripicola is described as a new species that was collected from a natural beach habitat and X. tentaculata is formally reported as newly found in Korea.

• Mycobiology
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• v.42 no.4
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• pp.391-396
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• 2014

In the past two decades, European ash trees (Fraxinus spp.) have been severely damaged due to ash dieback disease, which is caused by the fungal species Hymenoscyphus fraxineus (Chalara fraxinea in the anamorphic stage). Recent molecular phylogenetic and population genetic studies have suggested that this fungus has been introduced from Asia to Europe. During a fungal survey in Korea, H. fraxineus-like apothecia were collected from fallen leaves, rachises, and petioles of Korean ash and Manchurian ash trees. The morphological and ecological traits of these materials are described with the internal transcribed spacer rDNA sequence comparison of H. fraxineus strains collected from Korea, China and Japan.

• Molecules and Cells
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• v.25 no.3
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• pp.438-445
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• 2008

Leaf senescence is a highly regulated genetic process that constitutes the last stage of plant development and provides adaptive fitness by relocating metabolites from senescing leaves to reproducing seeds. Characterization of various senescence mutants, mostly in Arabidopsis, and genome-wide analyses of gene expression, have identified a wide array of regulatory components, including transcription factors and enzymes as well as signaling molecules mediating growth hormones and environmental stress responses. In this work we demonstrate that a membrane-associated NAC transcription factor, NTL9, mediates osmotic stress signaling in leaf senescence. The NTL9 gene is induced by osmotic stress. Furthermore, activation of the dormant, membrane-associated NTL9 is elevated under the same conditions. A series of senescence-associated genes (SAGs) were upregulated in transgenic plants overexpressing an activated form of NTL9, and some of them were slightly but reproducibly downregulated in a T-DNA insertional NTL9 knockout mutant. These observations indicate that NTL9 mediates osmotic stress responses that affect leaf senescence, providing a genetic link between intrinsic genetic programs and external signals in the control of leaf senescence.

• Journal of Microbiology and Biotechnology
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• v.16 no.9
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• pp.1459-1463
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• 2006

This study explored yeast diauxic promoters using a green fluorescent protein (GFP) reporter to screen growth phase-controlled promoters applicable for foreign protein production. Twenty-five diauxic promoters were inserted into a yeast 2-micron vector in front of the reporter GFP gene. The expressed GFP signal intensity measurements showed that 23 out of the 25 promoters produced a significant fluorescent signal when the cells were in the diauxic growth phase. Among the two strongest promoters pYDL204W and pYLR258W, the former remained constantly active after its activation at the diauxic shift, whereas the latter was only transiently activated right after the deprivation of the medium glucose.