• Korean Journal of Microbiology
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• v.41 no.3
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• pp.157-163
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• 2005

The acetate kinase gene from the copepod Paracyclopina nana was cloned. The open reading frame (ORF) was 1,200 bp, and poly(A) signal sequence was located in the end of the ORF. After the molecular phylogenetic analysis of P nana acetate kinase gene, it was revealed that it formed the same branch with that of Aspergillus. Also P. nana acetate kinase showed the difference with those of other prokaryotic microorganisms but showed the same clade with those of fungi. We also confirmed that the recombinant protein of P. nana acetate kinase made approximately 50 kDa after expression of recombinant gene construct in E. coli. This may be useful to compare this protein to those of other organisms in biochemical characteristics.

• Korean Journal of Environmental Biology
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• v.38 no.4
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• pp.650-657
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• 2020

We conducted a phylogeographic analysis of Korean endemic Zacco koreanus populations inhabiting the East-flowing river (Gangneung Yeongokcheon; GY, Yangyang Namdaecheon; YN), the Han River (Seomgang; SG, Soksacheon; SS), and the Nakdong River(Gilancheon; GA) using the mitochondrial DNA cytochrome oxidase I (COI) gene (619 bp). Population genetic analysis was further performed to assess the population connectivity for the GY river where there is a large number of human-made artificial weirs with several fishways. The phylogeographic analysis revealed that while the populations of the East-flowing river and those of the Han River formed a monophyletic lineage, the Nakdong River individuals represented a distinct lineage with 3.7-4.2% (mean=4.0%) genetic distance from the other lineages. The population genetic analysis of the GY showed that a mid-stream population harbored relatively higher mitochondrial diversity relative to up- and down-stream populations, and there was no genetic differentiation between these three populations. The latter findings might suggest high genetic connectivity between the populations via genetic flow along the fishways. However, an analysis using faster-evolving genetic markers, such as microsatellites, is needed to confirm the findings of high population connectivity. Our study suggests the possibility of the presence of cryptic species in Z. koreanus in the Nakdong River basin. However, further study with more individual samples as well as additional markers or even more advanced genomic tools is required to test our hypothesis. Ecological or phenotypic analyses should be conducted to test whether the observed Nakdong River lineage represents a different or cryptic species, or simply hidden, but excessive, intraspecific diversity.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.2
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• pp.128-136
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• 2006

This study was conducted for developing the stability parameter in uncontrolled landfill by using a biomolecular investigation on the microbial community growing through leachate plume. Landfill J(which is in Cheonan) and landfill T(which is in Wonju) were chosen for this study among a total of 244 closed uncontrolled landfills. It addressed the genetic diversity of the microbial community in the leachate by 165 rDNA gene cloning using PCR and compared quantitative analysis of denitrifiers and methanotrophs with the conventional water quality parameters. From the BLAST search, genes of 47.6% in landfill J, and 32.5% in landfill T, respectively, showed more than 97% of the similarity where Proteobacteria phylum was most significantly observed. It showed that the numbers of denitrification genes, i.e. nirS gene and cnorB gene in the J site are 7 and 4 times higher than those in T site, which is well reflecting from a difference of site closure showing 7 and 13 years after being closed, respectively. In addition, the quantitative analysis on methane formation gene showed that J1 spot immediately bordering with the sources has the greatest number of methane formation bacteria, and it was decreased rapidly according to distribute toward the outer boundary of landfill. The comparative investigation between the number of genes, i.e. nirS gene, cnorB gene and MCR gene, md the conventional monitoring parameters, i.e. TOC, $NH_3-N,\;NO_3-N,\;NO_2-N,\;Cl^-$, alkalinity, addressed that more than 99% of the correlation was observed except for the $NO_3-N$. It was concluded that biomolecular investigation was well consistent with the conventional monitoring parameters to interpret their influences and stability made by leachate plume formed in downgradient around the uncontrolled sites.

• Korean Journal of Clinical Laboratory Science
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• v.55 no.2
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• pp.71-81
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• 2023

This study examined the transition process of clinical laboratory technologists' national examination and job definition in Korea and compared the differences in the national examination between Korea and neighboring countries, such as Japan and Taiwan. In Korea, the number of questions made for it was 200 (1965), 200 (1977), 300 (1982), 250 (1992), 330 (2006), and 280 (2015). The practice of clinical physiology is important for real-time monitoring, given the characteristics of physiological testing. On the other hand, there are conflicts between other occupations in the working area. Clinical molecular biology needs to be established as a new major subject considering the diagnostic importance of molecular biological tests and the speed of science and technology development. Clinical laboratory operations provide policy and guidance recommendations to technologist staff. The proposed clinical laboratory technologists' national examination comprises major subjects: clinical biochemistry, clinical hematology, clinical transfusionology, clinical immunology, clinical microbiology, clinical molecular biology, clinical histology, clinical cytology, clinical physiology, and clinical laboratory operations. In addition, this study proposes the job definition of clinical laboratory technologists, revising various chemical or physiological testing to biomedical or physiological testing required for medical practice.

• Korean Journal of Food Science and Technology
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• v.45 no.3
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• pp.293-298
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• 2013

We aimed to provide the basic data for the development of a beverage using the juices from bioresources from Jeju. Our results show that pH and $^{\circ}Bx$ of the bioresources ranged 2.0-6.5 and 3.3-16.8, respectively. Rubus coreanus Miquel juice had the highest total phenol content (47.3 mg gallic acid equivalent (GAE)/100 mL). Citrus sphaerocarpa juice showed higher rates of 1,1-diphenyl-2-picryl hydrazyl (DPPH) radical scavenging (86.8%) than those of other juices. However, the oxygen radical absorbance capacity (ORAC) value ($2,409.5{\mu}M$ TE/mL) of Citrus sudachi Hort. ex Shirai juice was higher than those of other juices. A high correlation (R=0.7343) was observed between the pH and ORAC values for the 20 bioresources. Furthermore, a high correlation (R=0.8752) was found between the phenolic contents and DPPH radical scavenging for the 5 citrus fruits. These results suggest that the bioresources in Jeju could be used as natural antioxidants for the development of functional foods, including healthy beverages.

• Korean Journal of Clinical Laboratory Science
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• v.53 no.2
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• pp.143-150
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• 2021

The recent spread of novel and highly variant pathogenic viruses, including the coronavirus (SARS-CoV-2), has increased the demand for diagnostic testing for rapid confirmation. This has resulted in investigating the functional capability of each space, and preparing facility guidelines to secure the safety of medical technologists. During viral evaluations, there is a requirement of negative pressure facilities along with thread separation, during pre-treatment of samples and before nucleic acid amplification. Space composition therefore needs to be planned by considering unidirectional air flow. This classification of safety management facilities is designated as biosafety level 2, and personal protective equipment is placed accordingly. In case of handling dangerous materials, they need to be carried out of the biosafety cabinet, and sterilizers are required for suitable disposal of infectious agents. A common feature of domestic laboratories is maintenance of the sample pre-treatment space at a negative pressure of -2.5 Pa or less, and arranging separate pre-treatment and reagent preparation spaces during the test process. We believe that the data generated in this study is meaningful, and offers an efficient direction and detailed flow for separation of the inspection process and space functions. Moreover, this study introduces construction of the laboratory by applying the safety management standards.

• Korean Journal of Environmental Biology
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• v.41 no.1
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• pp.41-53
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• 2023

E171, a mixture of titanium dioxide, has been widely used as a food additive due to its whitening effect and low toxicity. However, it has been proven that E171 is no longer safe for public health. So far, there are insufficient studies on the toxic effects of E171 on organisms especially using standardized test methods. In this study, toxicity assessments of E171 to two aquatic species, water flea (Daphnia magna) and zebrafish (Danio rerio), were performed using modified standardized test methods based on the physicochemical properties of E171. The hydrodynamic diameter, polydispersity index, and turbiscan stability index (TSI) were measured to ensure the dispersion stability of E171 in exposure media during the test period. The EC₅₀ for immobilization of water flea was 141.7 mg L^-1 while zebrafish was not affected until 100 mg L^-1 of E171. Measurements of reactive oxygen species (ROS) and antioxidant enzyme activities confirmed that E171 induced oxidative stress, leading to the activation of superoxide dismutase and catalase in both water flea and zebrafish, although the expression of antioxidant enzyme genes differed between species. These results suggested the potential risk of E171 to aquatic organisms and provided toxicological insights into the impacts of E171 on the environment.

• Korean Journal of Plant Taxonomy
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• v.40 no.1
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• pp.1-15
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• 2010

Recognizing a basal group in a taxon is one of the most important factors involved in understanding the evolutionary history of that group of life. Many botanists have suggested a sister to all other angiosperms to understand the origin and rapid diversification of angiosperms based on morphological and fossil evidence. Recent technical advances in molecular biology and the accumulation of molecular phylogenetic data have provided evidence of the extant basal-most angiosperm which is a sister to all other angiosperms. Although it is still arguable, most plant taxonomists agree that Amborella trichopoda Baill., a species (monotypic genus and monotypic family) distributed in New Caledonia, is a sister to all other extant angiosperms based on evidence from the following molecular approaches: 1) classical phylogenetic analyses based on multiple genes (or DNA regions), 2) analyses of a tree network of duplicated gene families, and 3) gene-structural evidence. As an alternative hypothesis with relatively minor evidence, some researchers have also suggested that Amborella and Nymphaeaceae form a clade that is a sister to all other angiosperms. Debate regarding the basal-most angiosperms is still ongoing and is currently one of the hot issues in plant evolutionary biology. We expect that sequencing of the whole genome of Amborella as an evolutionary model plant and subsequent studies based on this genome sequence will provide information regarding the origin and rapid diversification of angiosperms, which is Darwin's so called abominable mystery.

• Economic and Environmental Geology
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• v.46 no.4
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• pp.345-350
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• 2013

In this study, the physicochemical properties of leachate and the bacteria existence in leachate using molecular biology methods for 4 animal carcass disposals on the disposal lapse time was analyzed. The result of leachate physicochemical analysis in the middle stage (been buried 20 months) showed higher EC, DO, $HCO_3{^-}$, TOC, T-N and $SO_4{^{2-}}$ concentration compared to the first stage data (been buried 5 months). For identification of leachate using 16S rRNA method, Lysinibacillus sphaericus, Bacillus pumilus, Pseudoclavibacter helvolus, Pseudochrobactrum saccharolyticum and Corynebacterium callunae in the first stage, Bacillus cereus, Lysinibacillus sphaericus, Bacillus circulans and Corynebacterium glutamicum in the middle stage was observed, while there were detections of pathogenicity bacteria such as B. cereus and L. sphaericus. This study improves our knowledge of the fate and transport in geologic media, treatment, risk analysis on the leachate from animal carcass disposal sites.

• Journal of Life Science
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• v.14 no.5
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• pp.752-760
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• 2004

The function of the [4Fe-4S] cluster containing iron (Fe-) protein in nitrogenase catalysis is to serve as the nucleotide-dependent electron donor to the MoFe protein which contains the sites for substrate binding and reduction. The ability of the Fe protein to function in this manner is dependent on its ability to adopt the appropriate conformation for productive interaction with the MoFe protein and on its ability to change redox potentials to provide the driving force required for electron transfer. The MgADP-bound (or off) conformational state of the nitrogenase Fe protein structure described reveals mechanisms for long-range communication from the nucleotide-binding sites to control affinity of association with the MoFe protein component. Two pathways, termed switches I and II, appear to be integral to this nucleotide signal transduction mechanism. In addition, the structure of the MgADP bound Fe protein provides the basis for the changes in the biophysical properties of the [4Fe-4S] observed when Fe protein binds nucleotides. The structures of the nitrogenase Fe protein with defined amino acid substitutions in the nucleotide dependent signal transduction pathways of the Switch I and Switch II have been determined by X-ray diffraction methods. These two pathways have been also implicated by site directed mutagenesis studies, structural analysis and analogies to other proteins that utilize similar nucleotide dependent signal transduction pathways. We have examined the validity of the assignment of these pathways in linking the signals generated by MgATP binding and hydrolysis to macromolecular complex formation and intermolecular electron transfer. The results provide a structural basis for the observed biophysical and biochemical properties of the Fe protein variants and interactions within the nitrogenase Fe protein-MoFe protein complex.