• Korean Journal of Environmental Biology
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• v.39 no.1
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• pp.55-67
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• 2021

A 210-day experiment was conducted to examine the effects of starvation on survival, external morphometric traits, and sectioned morphometric traits in Far Eastern catfish(Silurus asotus). The survival rate decreased to 92.2±0.47% in the fed group and to 74.4±2.59% in the starved group. Eight dimensions of Ls, DALPO/Ls, DADOP/Ls, ED/Ls, CH/Ls, BDAA/Ls, BDMA/Ls, and BWAA/Ls showed significant differences (p<0.05), and 16 other dimensions of DALAD/Ls, DPDPL/Ls, HPLAA/Ls, HALAV/Ls, HALOP/Ls, DAUPO/Ls, DADAV/Ls, DADAA/Ls, Max BL/Ls, Man BL/Ls, LD/Ls, HWOP/Ls, DAUF/HL, DAUS/HL, IW/HL, and DAUE/HL were not significantly different among the initial, fed, and starved groups (p>0.05). The fed group showed higher total height (THX), wider width (WX), and larger area (AX) than those of the starved group in each body section. This research provides information on the morphometric traits and body sections of starved Far Eastern catfish. These results can be used as a basic guide to indicate nutritional status and assist in aquaculture methods for Far Eastern catfish. Moreover, the methods used in this study were considered helpful because the survey analysis method can be used to investigate information on the nutritional status of other fish species.

• Korean Journal of Food Science and Technology
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• v.53 no.3
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• pp.239-244
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• 2021

In the present study, liquid chromatography tandem-mass spectrometry was used to conduct a risk assessment of ethoxyquin and ethoxyquin dimer residues in 288 farmed fish sold in wholesale and traditional markets in Seoul. The detection range (detection rate) of ethoxyquin and ethoxyquin dimer was 0.005~0.309 mg/kg (4.9%) and 0.001~2.828 mg/kg (69.8%), respectively. Ethoxyquin was detected only in freshwater eels, loaches, catfish, and flatfish, whereas ethoxyquin dimer was present in all fish species. To estimate the dietary exposure levels of ethoxyquin and ethoxyquin dimer, the hazard index, calculated using the acceptable daily intake and estimated daily intake, ranged from 0.001 to 0.300%. Our results indicate that there is no significant exposure risk to humans from these farmed fish despite 10 farmed fish samples exceeding the maximum residue level (1.0 mg/kg as the sum of ethoxyquin and ethoxyquin dimer).

• Microbiology and Biotechnology Letters
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• v.48 no.4
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• pp.463-470
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• 2020

The JS18 strain was isolated from an old tree forest and produced extracellular enzymes that decolorize synthetic melanin. Phylogenetic analysis, based on the internal transcribed spacer (ITS) sequence, indicate that JS18 belongs to the Trametes velutina species. JS18 demonstrated laccase activity but no manganese peroxidase or lignin peroxidase activity. Batch culture indicated that the melanin decolorization activity of JS18 strain originated from the laccase. Syringic acid and CuSO4 induced maximum laccase production, yielding 98 U/ml laccase activity after cultivation for 7 days at 25℃. T. velutina secretes an extracellular laccase in GYP medium, and this enzyme was purified using (NH4)2SO4 precipitation, Hi-trap Q Sepharose columns and gel filtration. The molecular weight of the purified enzyme was estimated to be 67 kDa using sodium dodecyl sulfate polyacrylamide gel electrophoresis. This enzyme produced 80% of its melanin decolorization activity within the first 24 h of evaluation in the presence of 1-hydroxybenzotriazole (HBT), while only about 4% of the melanin was decolorized in the absence of the mediator. The greatest decolorization was observed at 1.5 mM/l HBT, which decolorized 81% of the melanin within the first 24 h. The optimum pH and temperature for this decolorization were found to be 5.0 and 37℃, respectively. Our results suggest the possibility of applying HBT induced T. velutina JS18 laccase-catalyzed melanin decolorization.

• Korean Journal of Environmental Agriculture
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• v.40 no.1
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• pp.49-59
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• 2021

BACKGROUND: Soil salinity causes reduction of crop productivity. Rhizosphere microbes have metabolic capabilities and ability to adaptation of plants to biotic and abiotic stresses. Plant growth-promoting bacteria (PGPB) could play a role as elicitors for inducing tolerance to stresses in plants by affecting resident microorganism in soil. This study was conducted to demonstrate the effect of selected strains on rhizosphere microbial community under salinity stress. METHODS AND RESULTS: The experiments were conducted in tomato plants in pots containing field soil. Bacterial suspension was inoculated into three-week-old tomato plants, one week after inoculation, and -1,000 kPa-balanced salinity stress was imposed. The physiological and biochemical attributes of plant under salt stress were monitored by evaluating pigment, malondialdehyde (MDA), proline, soil pH, electrical conductivity (EC) and ion concentrations. To demonstrate the effect of selected Bacillus strains on rhizosphere microbial community, soil microbial diversity and abundance were evaluated with Illumina MiSeq sequencing, and primer sets of 341F/805R and ITS3/ITS4 were used for bacterial and fungal communities, respectively. As a result, when the bacterial strains were inoculated and then salinity stress was imposed, the inoculation decreases the stress susceptibility including reduction in lipid peroxidation, enhanced pigmentation and proline accumulation which subsequently resulted in better plant growth. However, bacterial inoculations did not affect diversity (observed OTUs, ACE, Chao1 and Shannon) and structure (principle coordinate analysis) of microbial communities under salinity stress. Furthermore, relative abundance in microbial communities had no significant difference between bacterial treated- and untreated-soils under salinity stress. CONCLUSION: Inoculation of Bacillus strains could affect plant responses and soil pH of tomato plants under salinity stress, whereas microbial diversity and abundance had no significant difference by the bacterial treatments. These findings demonstrated that Bacillus strains could alleviate plant's salinity damages by regulating pigments, proline, and MDA contents without significant changes of microbial community in tomato plants, and can be used as effective biostimulators against salinity stress for sustainable agriculture.

• Journal of Environmental Health Sciences
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• v.46 no.6
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• pp.636-645
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• 2020

Objectives: This study was performed to find phytoncide (monoterpene) emission characteristics and weather factors for application in prediction modeling for phytoncide weather services. Methods: From 2017 to 2019, one coniferous forest and one deciduous forest were selected to investigate the monthly emission characteristics and identify the correlation with weather factors. Research items were analyzed for 11 species known to be emitting the most monoterpenes. Results: Phytoncide (monoterpene) began to increase in April when trees were activated and continued to be released until November. The concentration range of monoterpene in deciduous forests was 0.0 to 427.4 ng/S㎥ and coniferous forests was 0.0 to 1,776.8 ng/S㎥. Phytoncide emission concentrations in deciduous forests were 20 to 90 percent of those in coniferous forests, and averaged 39 percent overall. The correlation between monoterpene and temperature was very close, with 0.835 for the broadleaf forest and 0.875 for the coniferous forest. Monoterpene and humidity were found to be 0.731 for the broadleaf forest and 0.681 for the coniferous forest, while wind speed showed a negative correlation of -0.482 and -0.424, respectively. Regression of temperature with phytoncide showed that the coefficient of determination (r2) was highly correlated with 0.75 for the broadleaf forest and 0.80 for the coniferous forest. Not only is phytoncide concentration affected by temperature, humidity, and wind speed, but also rainfall over the preceeding one to three days. Nearby rainfall on the day of sampling was found to have a direct effect on the physiological activities of the trees. Conclusions: Overall, if the values of monoterpene and temperature, humidity, and wind speed are used as basic factors, and rainfall from one to three days previous is replaced with complementary values, it is believed that the numerical analysis and modeling of daily and monthly phytoncide will be possible.

• Applied Chemistry for Engineering
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• v.32 no.1
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• pp.35-41
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• 2021

VWTi, which is used as a commercial catalyst in NH3-SCR, exhibits excellent denitrification performance at 300 to 400 ℃, but there is a problem that efficiency decreases at low temperatures below 300 ℃. Research on catalysts containing promoter to increase low-temperature denitrification efficiency is steadily progressing. However, research on the cause of the improvement in low-temperature denitrification efficiency of the catalyst and the catalyst properties is insufficient. In this study, it was confirmed that by adding Sb to VWTi, denitrification performance was improved by more than 10% in NH3-SCR reaction below 300 ℃. At this time, the space velocity and the size of the catalyst particles were controlled to exclude the influence of external/internal diffusion. In addition, the catalytic properties according to the presence or absence of Sb were investigated by performing BET, TEM/EDS, O2-TPD, H2-TPR and DRIFTs analysis. It was judged that the addition of Sb increased the adsorbed oxygen species on the surface of the catalyst, thereby enhancing the redox properties of the catalyst at low temperature and exhibiting excellent denitrification performance.

• Journal of the Korean Institute of Landscape Architecture
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• v.49 no.4
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• pp.1-14
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• 2021

This study examined the techniques of creating gardens overseas using native plants from the Korean peninsula, focusing on the case of 'Das Dritte Land', an art garden created in Berlin, Germany. While Korean garden artists are recognized worldwide and are planning to globalize Korean gardens, the purpose of this study is to share information so that Korean gardeners can expand their activities and rediscover the utilization and value of plants native to the Korean peninsula. The work began as part of a project to mark the 30th anniversary of the collapse of the Berlin Wall. To realize the landscape of Korea with the motif of Inwang Jesaekdo, the geographical shape of the Baekdu-Daegan trail was reproduced with black stone, and the naturalization of Korean peninsula species was utilized in the creation of a garden Berlin. It is a surreal bio-top utopia that blooms with the bio-groups of the Korean peninsula. This study examined the process of plant survey analysis, transportation and stabilization, planting planning, composition and monitoring, and targeting the self-growth of the Korean peninsula, which is a symbol of harmony between the South and the North. The planting of Korea's native plants in overseas gardens symbolizes the uniting of the ecosystems on the Korean peninsula. The process of the Korean peninsula's young plants taking root, flowering, and spreading along Germany's previously divided border metaphorically conveys the desire for the unification of the Korean peninsula. In addition, various art programs in the garden space suggest a foundation for cultural dialogue and communication between the two Koreas. Moreover, creating gardens overseas implies that the cooperation of plant research institutes plays an important role in the transfer of plants and the maintenance of life, while the advancement of Korean gardens overseas plays an essential role in the spread of garden culture in our country.

• Resources Recycling
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• v.30 no.4
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• pp.11-19
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• 2021

Arsenic (As) oxidation followed by precipitation from a high-As(III)-containing leaching solution derived from a sulfidic ore was investigated in this study to remove aqueous As from the solution using activated carbon (AC) with air injection as an oxidant. To obtain the initial leaching solution, a domestic sulfidic ore was leached in a sulfuric acid solution at pH 1 and 50℃ for 95 h, and approximately 7 g/L of Fe and 3 g/L of As were leached out. To determine the effect of the oxidative reaction utilizing AC with air injection, the leaching solution was tested under the following five oxidative conditions at an initial pH of 1 and 90℃ for 72 h: air-only injection; air injection with 1, 5, and 10 w/v% of AC addition; and H₂O₂ addition. The tests in the presence of both air and AC revealed that the oxidation kinetics and As removal were improved by the reaction between the metallic species and the surface group formed on the AC surface. In addition, the greater the amount of AC added, the better was the reaction efficiency, removing 93-94% of As with more than 5 w/v% of AC addition. Finally, X-ray diffraction analysis confirmed that the precipitate formed from the oxidative reaction was scorodite (FeAsO₄·2H₂O).

• Journal of Korean Society of Forest Science
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• v.111 no.1
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• pp.81-99
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• 2022

The Baekdudaegan, spanning around 701 km from Hyangrobong to Cheonwangbong of Mt. Jirisan in South Korea, is rich in biodiversity and known as the main ecological axis of the Korean Peninsula. The Neuljae-Yuksimnyeong section of Marugeum in the southern part of the Baekdudaegan, particularly Mt. Deogyusan, is an area in which various types of vegetation appear depending on the environmental characteristics. The aims of this study were to investigate the current vegetation status at the Neuljae-Yuksimnyeong section of the Baekdudaegan and to provide basic data to aid systematic conservation and management through future classification of forest vegetation types. A vegetation survey was conducted using 637 plots from May to October 2019. Vegetation-type analysis showed that the vegetation units could be classified as a Quercus mongolica community group divided into seven communities: the Abies koreana community, Sanguisorba hakusanensis community, Persicaria hydropiper community, Quercus variabilis community, Quercus dentata community, Cornus controversa community, and Quercus mongolica community. The A. koreana community was subdivided into the Dryopteris expansa group and Picea jezoensis group. The Q. variabilis community was also subdivided into the Q. dentata group and Q. variabilis typical group. We concluded that special management plans for distinctive forest vegetation, including subalpine vegetation, grass or herb vegetation, and agricultural vegetation, should be prepared urgently to aid ecosystem preservation and enhancement.

• Journal of the Korean earth science society
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• v.42 no.6
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• pp.623-631
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• 2021

The increased transport of marine hazardous and noxious substances (HNS) has resulted in frequent HNS spill accidents domestically and internationally. There are about 6,000 species of HNS internationally, and most of them have toxic properties. When an accidental HNS spill occurs, it can destroys the marine ecosystem and can damage life and property due to explosion and fire. Constructing a spectral library of HNS according to wavelength and developing a detection algorithm would help prepare for accidents. In this study, a ground HNS spill experiment was conducted in France. The toluene spectrum was determined through hyperspectral sensor measurements. HNS present in the hyperspectral images were detected by applying the spectral mixture algorithm. Preprocessing principal component analysis (PCA) removed noise and performed dimensional compression. The endmember spectra of toluene and seawater were extracted through the N-FINDR technique. By calculating the abundance fraction of toluene and seawater based on the spectrum, the detection accuracy of HNS in all pixels was presented as a probability. The probability was compared with radiance images at a wavelength of 418.15 nm to select abundance fractions with maximum detection accuracy. The accuracy exceeded 99% at a ratio of approximately 42%. Response to marine spills of HNS are presently impeded by the restricted access to the site because of high risk of exposure to toxic compounds. The present experimental and detection results could help estimate the area of contamination with HNS based on hyperspectral remote sensing.