• Environmental Analysis Health and Toxicology
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• v.22 no.1 s.56
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• pp.1-8
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• 2007

Biological monitoring, analyses of internal dose for exposure to toxicants, has been thought as one of the belt approaches for risk assessment. As the amount detected in human samples is generally very low, typically in the parts-per-bilion (ppb) or parts-per-trillion (ppt) range, analytic technologies such at HPLC, GC/MS, LC/MS, and LC/MS/MS have been continuously developed. In addition, route specific and sensitive exposure biomarkers have been developed for proper biological monitoring. PBPK modeling, particularly reverse dosimetry, has been emphasized as an useful method via interpretation of biological monitoring results for regulation of toxicants. Thus, this review is focused on the use of PBPK dosimetry models for toxicology research and risk assessment in Korea.

• Journal of Korean Society on Water Environment
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• v.27 no.2
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• pp.218-227
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• 2011

The objective approach for assessment of stream naturalness is an essential part of the stream restoration project. This study proposes the methodology for the assessment of stream naturalness considering physical, biological and chemical factors. Physical factors consists of riffle and pool, river bed material, bank protection, floodplain vegetation and levee materials; biological factors are benthic macroinvertebrate, KSI (Korean Saprobic Index), and IBI (Index of Biological Integrity) and chemical factors are pH, DO (dissolved oxygen), and TP (total phosphorus). This procedure is applied to the Mokgamcheon. As a result, the downstream of Mokgamcheon (zone I) needs the prompt improvement of stream naturalness, compared to the others (zone II and III). This evaluation technique will be an effective tool to quantify the stream naturalness and can be used to set the target of stream restoration project.

• Microbiology and Biotechnology Letters
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• v.44 no.1
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• pp.106-106
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• 2016

• The Plant Pathology Journal
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• v.38 no.2
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• pp.115-130
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• 2022

Though information exists regarding the pathogenesis of the shot-hole disease (SH) in flowering cherry (FC), there has been a lack of research focusing on SH management. Therefore, here, we investigated the inhibitory activities of antagonistic bacteria against SH pathogens both in vitro and in vivo as well as their biochemical characteristics and bioactive compounds. Two biosurfactant-producing bacterial antagonists, identified as Bacillus velezensis strains JCK-1618 and JCK-1696, exhibited the best effects against the growth of both bacterial and fungal SH pathogens in vitro through their cell-free culture filtrates (CFCFs). These two strains also strongly inhibited the growth of the pathogens via the action of their antimicrobial diffusible compounds and antimicrobial volatile organic compounds (VOCs). Crude enzymes, solvent extracts, and biosurfactants of the two strains exhibited antimicrobial activities. Liquid chromatography/electrospray ionization time-of-flight mass spectrometric analysis of the partially purified active fractions revealed that the two antagonists produced three cyclic lipopeptides, including iturin A, fengycin A, and surfactin, and a polyketide, oxydifficidin. In a detached leaf assay, pre-treatment and co-treatment of FC leaves with the CFCFs led to a large reduction in the severity of the leaf spots caused by Epicoccum tobaicum and Bukholderia contaminans, respectively. In addition, the two antagonists produced indole-3-acetic acid, siderophore, and a series of hydrolytic enzymes, along with the formation of a substantial biofilm. To our knowledge, this is the first report of the antimicrobial activities of the diffusible compounds and VOCs of B. velezensis against the SH pathogens and their efficiency in the biocontrol of SH.

• Journal of Korean Society on Water Environment
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• v.25 no.4
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• pp.606-614
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• 2009

To evaluate the biological water quality, diatom-based biological indices (DAIpo and TDI) were examined in the Sum-River and the Dal-stream. Having BOD concentrations below $2mg{\cdot}L^{-1}$ in most sites, water quality of both rivers was good. The DAIpo and TDI values ranged from 29.8 to 91.4 and from 38.7 to 93.0 respectively. From the biological water quality assessment, DAIpo and TDI for both rivers displayed fair to fairly poor water quality levels. However, the two indices showed more polluted conditions than expected from the BOD vlaues. In addition, DAIpo, having wider range of differences, appears to be more sensitive to the change in water quality when compared to TDI values. Statistical analysis using principal component analysis showed that Nitzschia palea and Diatoma vulgare might not be the appropriate indicators due to their low correlations with other indicators.

• Journal of Korean Society on Water Environment
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• v.22 no.5
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• pp.768-783
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• 2006

Biological stream environment assessment has been an essential trend of aquatic ecosystems among advanced countries, because the chemical water quality assessment has limitations that only represent temporal water environmental status. Benthic macroinvertebrates are the most popular bioindicator group useful to biological water quality assessment for a long time. In addition, a number of indices using benthic macroinvertebrates have recently been developed not only for water quality assessment but also for ecological health assessment. In this paper Korean Saprobic Index (KSI) based on Zelinka-Marvan's saprobic valency concept is developed by applying DIN 38410 in Germany. The KSI value was widely applicable to most Korean streams with the exception of sand-based large streams, for example main stream of Nakdong River. But as a result of non-linear regression analysis the correlation between KSI and $BOD_5$ concentration was high and KSI reflected water quality alteration for mid and long-term period. In spite of applicability of KSI, it should be supplemented and developed to make it strong by accumulating field data as well as to manage integrated water environment in general through continuous biomonitoring.

• Ecology and Resilient Infrastructure
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• v.2 no.2
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• pp.108-117
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• 2015

This study was carried out to assess problems related to legislative regulations and guidelines concerning some biological assessment systems applied to stream corridor in Korea. We comparatively reviewed the law of stream corridors and the guidelines for master plan concerned, and the law of water quality and health assessment criteria for the aquatic ecosystem concerned. Stream environments were not managed effectively due to the absence of detail regulations and the criteria for stream assessment. A biological assessment system was not equivalently integrated within the management of water resources in process implementation of projects resulting from the dualistic management system for stream corridors in Korea. The current biological assessment system was reflected to mainly physical habitats or only oriented to some aquatic species correlated with water quality. This system was also recognized as part of environment impact assessment based on an intensive survey method of most biological taxa. Conclusively rapid and quantitative assessment techniques based on advanced organisms, such as vegetation, fish and birds, etc. should be urgently provided for considering as representative indicators of stream conditions in Korea.

• Journal of Food Hygiene and Safety
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• v.32 no.3
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• pp.243-248
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• 2017

Intracellular and extracellular oxidative stress initiated by reactive oxygen species (ROS) causes skin aging, which is characterized by wrinkles and atypical pigmentation. Use of antioxidant is an effective approach to prevent symptoms related to ROS-induced aging of the skin. Therefore, the antioxidant and anti-aging effect of Castanea crenata Siebold & Zucc. extracts (LCE) was investigated in this study. The LCE markedly reduced the hydrogen peroxide-induced cell damage, intracellular ROS, and oxidative stress-induced senescence in human dermal fibroblasts (HDFs). These results indicate that LCE might have beneficial effects on oxidative stress-induced damage and thus reduce skin aging.

• Microbiology and Biotechnology Letters
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• v.45 no.2
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• pp.168-177
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• 2017

Strain A28-5, which can degrade xylan and agar in solid medium, was isolated from a coastal seawater sample collected from Jeju Island, South Korea. This strain was found to be a gram-negative, $Na^+$-requiring bacterial strain with a polar flagellum for motility. Additionally, the strain was tolerant to antibiotics such as ampicillin and thiostrepton. The G+C content of the genome was 43.96% and menaquinone-7 was found to be the predominant quinone. Major fatty acids constituting the cell wall of the strain were $C_{16:1}$ ${\omega}7c/iso-C_{15:0}$ 2-OH (23.32%), $C_{16:0}$ (21.83%), and $C_{18:1}$ ${\omega}7c$ (17.98%). The 16S rRNA gene sequence of the strain showed the highest similarity (98.94%) to that of Catenovulum agarivorans YM01, which was demonstrated by constructing a neighbor-joining phylogenetic tree. A28-5 was identified as a novel species of the genus Catenovulum via DNA-DNA hybridization with Catenovulum agarivorans YM01, and thus was named as Catenovulum jejuensis A28-5. The formation of tetramers and hexamers of xylooligosaccharides and (neo)agarooligosaccharides, respectively, were confirmed by thin-layer chromatography analysis using an enzyme reaction solution containing xylan or agarose with two crude enzymes prepared from the liquid culture of the strain.

• The Korean Journal of Food And Nutrition
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• v.28 no.6
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• pp.1098-1106
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• 2015

This study aimed to investigate antioxidant activities from 11 forest plants, and determine their total phenolics, flavonoids and proantocyanidins contents. In addition, the antioxidant activities were correlated with antioxidant compounds. Among the samples, Cornus officinalis, Castanea crenata, Lindera erythrocarpa, Carpinus laxiflora and Pourthiaea villosa showed significantly higher 2,2-diphenyl-1-picrylhydrazyl (DPPH) ($IC_{50}=21.12{\sim}28.93{\mu}g/mL$) and 2,2'-azino-bis(3-ethylbenzothia zoline-6-sulfonic acid) (ABTS) ($IC_{50}=28.18{\sim}52.55{\mu}g/mL$) radical scavenging ability with reducing power ($IC_{50}=59.91{\sim}93.64{\mu}g/mL$) than other plants; and C. crenata, L. erythrocarpa and Rubus coreanus showed strong nitric oxide (NO) inhibition activity (${\geq}60%$). In addition, L. erythrocarpa, C. laxiflora and P. villosa showed higher oxygen radical absorbance capacity (ORAC) values (${\geq}1,100{\mu}M$ TE/g sample) than other samples. High total phenolic contents were observed in C. crenata (429.11 mg GAE/g), L. erythrocarpa (437.11 mg GAE/g), C. laxiflora (408.67 mg GAE/g) and P. villosa (404.11 mg GAE/g). The DPPH and ABTS radical scavenging activity with reducing power were significantly correlated with total phenolic contents ($R^2=0.71{\sim}0.79$), but total phenolic contents were not correlated with NO inhibition and ORAC ($R^2=0.35{\sim}0.43$). Therefore, these results suggested that C. officinalis, C. crenata, L. erythrocarpa, C. laxiflora and P. villosa are potential natural antioxidative candidate ingredients.