• 한국균학회지
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• 제46권4호
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• pp.383-392
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• 2018

During the study of indigenous fungal communities in soil samples collected from various field soils in Sancheong, Gyeongsangnam-do, Korea in 2017, several species of Aspergillus were discovered. Aspergillus caninus (KNU17-7) was isolated, identified, and described based on the results from macro and micro morphological characteristics and molecular characterization. Morphologically, it was identified using five different growth media: potato dextrose agar, oatmeal agar, yeast extract sucrose agar, czapek yeast extract agar, and malt extract agar. For the molecular identification, sequencing of internal transcribed spacer, ${\beta}-tubulin$, and calmodulin genes was performed. Based on this characterization, our study isolate was identified as Aspergillus caninus. This fungal species has not been officially reported in Korea before, and we report here with its morphological and molecular phylogenetic characterization.

• Journal of Species Research
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• 제11권4호
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• pp.310-320
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• 2022

As a subset study to discover indigenous prokaryotic species in Korea, we isolated 20 bacterial strains and assigned them to the phyla Actinobacteria, Bacteroidota, Firmicutes, and Proteobacteria. From the high 16S rRNA gene sequence similarity (≥98.7%) and formation of a robust phylogenetic clades, we determined that each strain belonged to independent, predefined bacterial species. There are no official reports of these 20 species in Korea; therefore, 7 strains of the Actinobacteria, 2 strain of the Bacteroidota, 3 strains of the Firmicutes, and 8 strains of the Firmicutes are described in Korea for the first time. Gram reaction, colony and cell morphology, basic biochemical characteristics, and isolation sources are also described in the species description section.

• Molecules and Cells
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• 제26권4호
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• pp.338-343
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• 2008

An embryonic stem cell is a powerful tool for investigation of early development in vitro. The study of embryonic stem cell mediated neuronal differentiation allows for improved understanding of the mechanisms involved in embryonic neuronal development. We investigated expression profile changes using time course cDNA microarray to identify clues for the signaling network of neuronal differentiation. For the short time course microarray data, pattern analysis based on the quadratic regression method is an effective approach for identification and classification of a variety of expressed genes that have biological relevance. We studied the expression patterns, at each of 5 stages, after neuronal induction at the mRNA level of embryonic stem cells using the quadratic regression method for pattern analysis. As a result, a total of 316 genes (3.1%) including 166 (1.7%) informative genes in 8 possible expression patterns were identified by pattern analysis. Among the selected genes associated with neurological system, all three genes showing linearly increasing pattern over time, and one gene showing decreasing pattern over time, were verified by RT-PCR. Therefore, an increase in gene expression over time, in a linear pattern, may be associated with embryonic development. The genes: Tcfap2c, Ttr, Wnt3a, Btg2 and Foxk1 detected by pattern analysis, and verified by RT-PCR simultaneously, may be candidate markers associated with the development of the nervous system. Our study shows that pattern analysis, using the quadratic regression method, is very useful for investigation of time course cDNA microarray data. The pattern analysis used in this study has biological significance for the study of embryonic stem cells.

• 한국어업기술학회:학술대회논문집
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• 한국어업기술학회 2002년도 춘계 수산관련학회 공둥학술발표회
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• pp.412-413
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• 2002

• 한국환경생물학회:학술대회논문집
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• 한국환경생물학회 2001년도 학술대회
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• pp.80-81
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• 2001

• 한국동물학회:학술대회논문집
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• 한국동물학회 2003년도 한국생물과학협회 학술발표대회
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• pp.203.2-203
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• 2003

No Abstract, See Full Text

• BMB Reports
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• 제55권9호
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• pp.439-446
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• 2022

Pyridoxal 5'-phosphate (PLP)-dependent enzymes are ubiquitous, catalyzing various biochemical reactions of approximately 4% of all classified enzymatic activities. They transform amines and amino acids into important metabolites or signaling molecules and are important drug targets in many diseases. In the crystal structures of PLP-dependent enzymes, organic cofactor PLP showed diverse conformations depending on the catalytic step. The conformational change of PLP is essential in the catalytic mechanism. In the study, we review the sophisticated catalytic mechanism of PLP, especially in transaldimination reactions. Most drugs targeting PLP-dependent enzymes make a covalent bond to PLP with the transaldimination reaction. A detailed understanding of organic cofactor PLP will help develop a new drug against PLP-dependent enzymes.

• Journal of Microbiology and Biotechnology
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• 제32권1호
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• pp.27-36
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• 2022

Ever since bioplastics were globally introduced to a wide range of industries, the disposal of used products made with bioplastics has become an issue inseparable from their application. Unlike petroleum-based plastics, bioplastics can be completely decomposed into water and carbon dioxide by microorganisms in a relatively short time, which is an advantage. However, there is little information on the specific degraders and accelerating factors for biodegradation. To elucidate a new strain for biodegrading poly-3-hydroxybutyrate (PHB), we screened out one PHB-degrading bacterium, Microbulbifer sp. SOL03, which is the first reported strain from the Microbulbifer genus to show PHB degradation activity, although Microbulbifer species are known to be complex carbohydrate degraders found in high-salt environments. In this study, we evaluated its biodegradability using solid- and liquid-based methods in addition to examining the changes in physical properties throughout the biodegradation process. Furthermore, we established the optimal conditions for biodegradation with respect to temperature, salt concentration, and additional carbon and nitrogen sources; accordingly, a temperature of 37℃ with the addition of 3% NaCl without additional carbon sources, was determined to be optimal. In summary, we found that Microbulbifer sp. SOL03 showed a PHB degradation yield of almost 97% after 10 days. To the best of our knowledge, this is the first study to investigate the potent bioplastic degradation activity of Microbulbifer sp., and we believe that it can contribute to the development of bioplastics from application to disposal.

• Journal of Ecology and Environment
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• 제45권4호
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• pp.313-327
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• 2021

Background: Citizen science is becoming a mainstream approach of baseline data collection to monitor biodiversity and climate change. Dragonflies (Odonata) have been ranked as the highest priority group in biodiversity monitoring for global warming. Ischnura senegalensis Rambur has been designated a biological indicator of climate change and is being monitored by the citizen science project "Korean Biodiversity Observation Network." This study has been performed to understand changes in the distribution range of I. senegalensis in response to climate change using citizen science data in South Korea. Results: We constructed a dataset of 397 distribution records for I. senegalensis, ranging from 1980 to 2020. The number of records sharply increased over time and space, and in particular, citizen science monitoring data accounted for the greatest proportion (58.7%) and covered the widest geographical range. This species was only distributed in the southern provinces until 2010 but was recorded in the higher latitudes such as Gangwon-do, Incheon, Seoul, and Gyeonggi-do (max. Paju-si, 37.70° latitude) by 2020. A species distribution model showed that the annual mean temperature (Bio1; 63.2%) and the maximum temperature of the warmest month (Bio5; 16.7%) were the most critical factors influencing its distribution. Future climate change scenarios have predicted an increase in suitable habitats for this species. Conclusions: This study is the first to show the northward expansion in the distribution range of I. senegalensis in response to climate warming in South Korea over the past 40 years. In particular, citizen science was crucial in supplying critical baseline data to detect the distribution change toward higher latitudes. Our results provide new insights on the value of citizen science as a tool for detecting the impact of climate change on ecosystems in South Korea.

• 대한의용생체공학회:의공학회지
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• 제17권2호
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• pp.227-234
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• 1996

This paper is the study of the diffusion constant in order to calculate the percent oxygenation and percent blood volume using reflectance light within biological tissue. The diffusion constant play major role in percent oxygenation and percent blood volume and varies with the biological material such as hemolyzed blood, whole blood, dermis and epidermis in vivo tissue. The diffusion constant can be modeled to consist of a contribution from bloodless tissue and blood present in tissue. The reflectance light for experimental are red light of 660nm, infrared light of 880nm, green light of 569nm. The correlation between the diffusion constant and biological tissue was analyzed by the intensity of reflectance light at different depth within human limb. The reflectance light was changed in response to physiological changes within biological tissue. The data for diffusion constant were obtained at different depth beneath the surface of the skin and will be utilized to amen the percent oxygenation and percent blood volume.