• Korean Journal of Ecology and Environment
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• v.53 no.2
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• pp.165-172
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• 2020

Heavy metals are common pollutants in the freshwater environment and have toxicological effect in habitat organisms. The heavy metals highly accumulated in sediment and organism, and observed various physiological responses. In this study, we investigated the molecular response to heavy metal toxicity (Al, Aluminum; Cr, Chromium; Cu, copper; Mn, Manganese; Zn, Zinc) through expression of heat shock protein 40, 70, 90 (HSP40, 70, 90), cytochrome 450 (CYP450), Glutathione S-transferase (GST) and Serine-type endopeptidase (SP). HSPs showed up-regulation in Cu and Zn exposures. Furthermore, HSPs expression in treated groups tended to be higher than the control group. The tendency of CYP450 and GST mRNA expression was higher for Cr and Cu than for other exposure group. The expression of SP gene was low at Al exposure and other group were measured to be similar to control. These results suggest that heavy metal toxicity in freshwater ecosystem may affect physiological and molecular process. Also, the comprehensive gene expression in the aquatic midge Chironomus riparius give useful information to potential molecular biomarkers for assessing heavy metal toxicity.

• Journal of the Korean Institute of Landscape Architecture
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• v.40 no.6
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• pp.35-46
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• 2012

This study attempts to specifically analyze green volume and scenery characteristics by classifying the streets in Seoul and suggest improvements accordingly. The subject streets for research were limited to those that have high occupancy ratio and are wide enough to have a big potential in improving green volume. In terms of green volume and scenery according to the types of streets, Platanus occidentalis and Ginkgo biloba were most common regardless of the street type, and the green ratio was 51.6% in residential areas, 50.4% in commercial areas, and 43.7% in business areas. Apart from the residential area, there was almost no green areas, and the ratio of green coverage was 71.0% in business areas, 64.0% in green areas, 37.3% in residential areas, and 36.2% in commercial areas, while the green volume coefficient was $1.9m^3/m^2$ on average. Based on the study results, it was set as a goal to provide the residential areas with a green community space and flowering trees throughout the year for scenery, and commercial areas with flowering trees and maples to emphasize the stores' image while not interfering with service and walking. For business areas, the goals were to improve green ratio and create streets that suit the urban image, and to set up spaces to provide habitat for wild animals with multi-layer planting and link to surrounding forests.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.32 no.4
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• pp.295-307
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• 2006

Styela clava, called non-native tunicate or sea squirt, is habitat which include bays and harbors in Korea and several sites in the sea faced world. We fabricate cellulose membrane nerve conduit (CMNC) from this native sea squirt skin, and evaluate the capacity of promoting peripheral nerve regeneration in the rat sciatic nerve defect model. After processing the pure cellulose membrane from the sea squirt skin as we already published before, CMNC was designed as a non-tubular sheet with 14 mm length and 4 mm width. Total eleven male Spraque-Dawley rats (12 weeks, weighing 250 to 300g) were divided into sham group (n=2), silicone tube grafted control group (n=3) and experimental group (n=6). Each CMNC grafted nerve was evaluated after 4, 8 and 12 weeks in the experimental group, and after 12 weeks, sciatic function was evaluated with sciatic function index (SFI) and gait analysis, and histomorphology of nerve conduit and the innervated tissues of sciatic nerve were all examined using image analyzer and electromicroscopic methods in the all groups. The regenerated axon and nerve sheath were found only in the inner surface of the CMNC after 4 weeks and became more thicker after 8 and 12 weeks. In the TEM study, CMNC grafted group showed more abundant organized myelinated nerve fibers with thickened extracellular matrix than silicone conduit grafted group after 12 weeks. The sciatic function index (SFI) and ankle stance angle (ASA) in the functional evaluation were $-47.2{\pm}3.9$, $35.5^{\circ}{\pm}4.9^{\circ}$ in CMNC grafted group (n=2) and $-80.4{\pm}7.4$, $29.2^{\circ}{\pm}5.3^{\circ}$ in silicone conduit grafted group (n=3), respectively. And the myelinated axon was 41.59% in CMNC group and 9.51% in silicone conduit group to the sham group. The development of a bioactive CMNC to replace autogenous nerve grafts offers a potential and available approach to improved peripheral nerve regeneration. As we already published before, small peptide fragment derived from the basement membrane matrix proteins of squirt skin, which is a kind of anchoring protein composed of glycocalyx, induced the effective axonal regeneration with rapid growth of Schwann cells beneath the inner surface of CMNC. So the possibilities of clinical application as a peripheral nerve regeneration will be able to be suggested.

• Journal of Life Science
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• v.26 no.6
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• pp.711-720
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• 2016

To determine the degree of common genes and the phylogenetic relationships among genome-sequenced 680 prokaryotes, the similarities among 4,631 clusters of orthologous groups of protein (COGs)’ presence/ absence and gene content trees were analyzed. The number of COGs was in the range of 103–2,199 (mean 1377.1) among 680 prokaryotes. Candidatus Nasuia deltocephalinicola str. NAS-ALF, an obligate symbiont with insects, showed the minimum COG, while Pseudomonas aeruginosa PAO1, an opportunistic pathogen, represented the maximum COG. The similarities between two prokaryotes were 49.30–99.78 % (mean 72.65%). Methanocaldococcus jannaschii DSM 2661 (hyperthermophilic and autotrophic, Euryarchaeota phylum) and Mesorhizobium loti MAFF303099 (mesophilic and symbiotic, alpha-Proteobacteria class) had the minimum amount of similarities. As gene content may represent the potential for an organism to adapt to each habitat, this may represent the history of prokaryotic evolution or the range of prokaryotic habitats at present on earth. COG content trees represented the following. First, two members of Chloroflexi phylum (Dehalogenimonas lykanthroporepellens BL-DC-9 and Dehalococcoides mccartyi 195) showed a greater relationship with Archaea than other Eubacteria. Second, members of the same phylum or class in the 16S rRNA gene were separated in the COG content tree. Finally, delta- and epsilon-Proteobacteria were in different lineages with other Proteobacteria classes in neighbor-joining (NJ) and maximum likelihood (ML) trees. The results of this study would be valuable to identifying the origins of organisms, functional relationships, and useful genes.

• Journal of the Korean association of regional geographers
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• v.7 no.3
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• pp.14-28
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• 2001

This study is to discuss the problems due to the maldevelopment occurred at the reserved areas of natural environments of the Ulleung Island, Gyeongsangbuk-do province, and it also suggests the ways of solving them The types of the maldevelopment practiced on the Ulleung Island consist of the change of land use, the opening of a round road, the destruction of mountains for the construction of harbor, the development of tourist areas, and the construction of military facilities. The decreased habitat of animals and the pollution of drinking water are occurred by the change of land use. The destruction of ecological system is due to the opening of a round road. The damage of natural landscape and the change of ocean eco-system is closely related to the construction of harbor and the destruction of mountains. Finally, the damage of rare plants and the pollution of drinking water are due to the development of tourist areas and the construction of military facilities. In the followings, the ways of solving the problems occurred by the various types of maldevelopment are suggested. First, the planning of pro-environmental development has to be established and practiced to preserve rare plants which are damaged due to the change of land use. Second, the destruction of natural landscape and resources has to be minimized by the implementation of environmental impact assesment when road and harbor are constructed. Third, the stones needed for the development of islands ought to be imported from mainland. Fourth, the established tourist areas are needed to rationally manage and the potential tourist areas has to be transferred to the reserved areas of natural environments. Fifth, military facilities should be constructed though the cooperation of autonomous local government. Finally, government officers' and residents' conscience of protecting and reserving natural environments is needed, and government has to give residents financial supports.

• Microbiology and Biotechnology Letters
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• v.40 no.3
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• pp.261-267
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• 2012

Coastal sand dunes are important for ecosystems due to the variety of rare species that can be found in this kind of habitat, and the beautiful landscapes they create. For environmental remediation, a potential strategy is phytoremediation using the symbiotic relationship of plants and microbes in the rhizosphere, which has proven ecologically sound, safe, and cost effective. Ninety-five colonies were isolated from the rhizosphere soil (RS) or rhizoplane (RP) of Rorippa islandica, Rumex crispus, Artemisia princeps var. orientalis, Lilium sp Stellaria media, and Gramineae. These colonies were then tested for plant growth promoting activities (PGPAs) such as 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase activity, and siderphores synthesis ability. In addition, salt tolerance was evaluated at 4% and 8% salt concentrations. It was observed that amongst the test subjects about 50% of the strains had a high resistance to salinity. Many of them could produce indole-3-acetic acid (IAA) IAA (in RS 13.9% and in RP 7.6%), exhibited ACC deaminase activity (55.8% in RS and 36.6% in RP), and could synthesize siderphores (62.7% in RS and 50% in RP). Correlation coefficient analyses were carried out for the three kinds of plant growth promoting abilities (PGPA) and salt tolerance. A positive correlation was found between an ability to synthesize siderphores and ACC deaminase activity (r=0.605, p<0.037). Similarly, positive correlations were noted between salt tolerance and ACC deaminase activity (r=0.762, p<0.004, r=0.771), and salt tolerance and an ability to synthesize siderphores (r=0.771, p<0.003).

• Korean Journal of Microbiology
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• v.33 no.4
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• pp.267-273
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• 1997

Various physico-chemical and microbiological parameters of a composting system were compared with respect to their potential use for the monitoring and evaluation of composting processes for cattle manure. The temperature changed within a range of $30-65^{\circ}C$ during the whole composting process, and the period of active composting (>$40^{\circ}C$) persisted for 16 days. The concentrations of total carbon, total nitrogen, and organic matter decreased by 15% during active composting, but significant changes in C/N ratio were not observed. The decrease of temperature in the latter period of active composting caused a decrease of $NH_4^+-N$ and an increase of $NO_3^--N$ in the composting pile. When temperature exceeded $50^{\circ}C$, the population of thermophiles was higher than that of mesophiles by more than 1 or 2 orders of magnitude. Correlation analyses showed that amylase activity correlated positively with the population of mesophiles and reducing sugar content, but negatively with the population of thermophiles. Amylase activity was higher at the beginning of active composting, whereas cellulase, xylanase and ligninase activities which showed close relationship with each other, increased continually during active cornposting, suggesting the distinction of temporal niches between amylose-degrading and lignocellulose-degrading bacteria in the same habitat.

• Proceedings of the Korea Water Resources Association Conference
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• 2016.05a
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• pp.1-1
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• 2016

Many of the world's large ecosystems are severely stressed due to population growth, water quality and quantity problems, vulnerability to flood and drought, and the loss of native species and cultural resources. Consequences of climate change further increase uncertainties about the future. These major societal challenges must be addressed through innovations in governance, policy, and ways of implementing management strategies. Science and engineering play a critical role in helping define possible alternative futures that could be achieved and the possible consequences to economic development, quality of life, and sustainability of ecosystem services. Science has advanced rapidly during the past decade with the emergence of science communities coalescing around 'Grand Challenges' and the maturation of how these communities function has resulted in large interdisciplinary research networks. An example is the River Experiment Center of KICT that engages researchers from throughout Korea and the world. This trend has been complemented by major advances in sensor technologies and data synthesis to accelerate knowledge discovery. These factors combine to allow scientific debate to occur in a more open and transparent manner. The availability of information and improved communication of scientific and engineering issues is raising the level of dialogue at the science-policy interface. However, severe challenges persist since scientific discovery does not occur on the same timeframe as management actions, policy decisions or at the pace sometimes expected by elected officials. Common challenges include the need to make decisions in the face of considerable uncertainty, ensuring research results are actionable and preventing science being used by special interests to delay or obsfucate decisions. These challenges are explored in the context of examples from the United States, including the California Bay-Delta system. California transfers water from the wetter northern part of the state to the drier southern part of the state through the Central Valley Project since 1940 and this was supplemented by the State Water Project in 1973. The scale of these activities is remarkable: approximately two thirds of the population of Californians rely on water from the Delta, these waters also irrigate up to 45% of the fruits & vegetables produced in the US, and about 80% of California's commercial fishery species live in or migrate through the Bay-Delta. This Delta region is a global hotspot for biodiversity that provides habitat for over 700 species, but is also a hotspot for the loss of biodiversity with more than 25 species currently listed by the Endangered Species Act. Understanding the decline of the fragile ecosystem of the Bay-Delta system and the potential consequences to economic growth if water transfers are reduced for the environment, the California State Legislature passed landmark legislation in 2009 (CA Water Code SS 85054) that established "Coequal goals of providing a more reliable water supply for California and protecting, restoring, and enhancing the Delta ecosystem". The legislation also stated that "The coequal goals shall be achieved in a manner that protects and enhances the unique cultural, recreational, natural resource, and agricultural values of the Delta as an evolving place." The challenges of integrating policy, management and scientific research will be described through this and other international examples.

• Korean Journal of Microbiology
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• v.55 no.3
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• pp.242-247
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• 2019

Biological factors (e.g. microorganism activity) in wastewater treatment plant (WWTP) play essential roles for degradation and/or removal of organic matters. In this study, to understand the microbial functional roles in WWTP, we tried to isolate and characterize a bacterial strain from activated sludge sample. Strain S16 was isolated from the activated sludge of a municipal WWTP in Daejeon metropolitan city, the Republic of Korea. The cells were a Gram-stain-positive, non-motile, facultative anaerobe, and rod-shaped. Strain S16 grew at a temperature of $15{\sim}40^{\circ}C$ (optimum, $30^{\circ}C$), with 0~9.0% (w/v) NaCl (optimum, 1.0~2.0%), and at pH 5.5~9.0 (optimum, pH 7.0~7.5). Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain S16 was most closely related to the unique species Miniimonas arenae NBRC $106267^T$ (99.79%, 16S rRNA gene sequence similarity) of the genus Miniimonas. The cell wall contained alanine, glutamic acid, serine, and ornithine. Although the isolation source of the type strain NBRC $106267^T$ which considered as a marine microorganism is sea sand, that of strain S16 is terrestrial environment. It might raise an ecological question for habitat transition. Therefore, comparative genome analysis will be valuable investigation for shedding light on their potential metabolic traits and genomic streamlining.

• Journal of Korean Society of Forest Science
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• v.110 no.1
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• pp.22-34
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• 2021

The implementation of the sunset provision of unexecuted urban parks in Seoul has been postponed; however, the mentioned parks still remain vulnerable since they can be subject to development under certain circumstances. Local governments may purchase the parks to prevent their loss but are constrained due to limited resources. The purpose of this study is to prioritize the purchase of unexecuted urban parks in Seoul based on landscape connectivity, which represents the important role of allowing the movement of wildlife and providing biodiversity in urban environments. In this study, we used four potential scenarios (PB100, PB1, PA100, PA1), which reflects the degree of land cover change resulting from the implementation of the sunset provision, and the role of Han River as a conduit or barrier for wildlife movement. Landscape connectivity was evaluated by calculating current flow betweenness centrality (CFBC). This was used to rank the importance of the unexecuted urban parks in Seoul. The results demonstrated that the implementation of the sunset provision will greatly decrease the connectivity of all parks in Seoul and particularly more so for parks in the southern part of the city. In addition, the results suggested that the low connectivity of Han river will diminish the connectivity around Bukhansan Mountain in the northern part of Seoul. Our study can be used for the prioritization of purchase, since it has the ability to evaluate the anticipated vulnerability of each park's connectivity after the sunset provision.