• Food Science of Animal Resources
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• v.23 no.1
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• pp.80-85
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• 2003

This study was carried out to investigate antimicrobial and antitumoral activities of Candida kefyr TFP7 isolated from Tibetan fermented milk Strains of TFP1∼10 were isolated from Tibetan fermented milk by agar diffusion method using potato dextrose agar(PDA). Antimicrobial activities were examined against 18 microorganisms of food-related bacteria, yeast, algae, fungi and actinomycetes isolated from soil. Antitumor activities were examined against 9 human tumor cell lines. Strains of TFP2∼10 showed strong antimicrobial activities against Micrococcus luteus ATCC l1880, and strains of TFP6∼10 to actinomycetes, Streptomyces murinus JCM 4333. In antitumor test, all isolated strains(TEP1∼10) showed the growth inhibition of SNU-5 and SW-534 by 60% and 70%, respectively. Among those, the strain TFP7 showed the most antitumor activity, which was 77.5% for SNU-5 and 76.5% for SW-534. The strain was identified as Candida kefyr by use of API 20C AUX kit and scanning electron micrograph.

• Journal of Species Research
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• v.7 no.1
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• pp.50-59
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• 2018

During the course of investigation of indigenous prokaryotic species in Korea, a total of 30 bacterial strains belonging to the phylum Firmicutes were isolated from diverse environmental sites such as soil, avian feces, wastewater treatment plants, fermented vegetables, seawater, algae, sea cucumber, octopus and tidal flat sediment. Phylogenetic analysis based on 16S rRNA gene sequences revealed that each strain showed high sequence similarity (${\geq}98.7%$) to the closest type strain and formed a robust phylogenetic clade with the most closely related species in the phylum Firmicutes. To date, there is no official record of these 30 species in Korea. Therefore, we report 26 species of 12 genera in the order Bacillales and 4 species of 4 genera in the order Lactobacillales which have not been reported in Korea. Morphological and biochemical characteristics, isolation sources and NIBR deposit numbers are described in the species descriptions.

• Journal of Korean Society on Water Environment
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• v.31 no.2
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• pp.159-165
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• 2015

The organic matter sources of phytoplankton and related environmental factors influencing algal bloom in Paldang reservoir were studied using nitrogen and carbon isotope ratio(${\delta}^{15}N$, ${\delta}^{13}C$). Phytoplankton samples for stable isotope analysis were collected from four points in reservoir using a plankton net. Physicochemical water quality, algal taxa and hydrological data were collected from published monitoring material. Phytoplankton samples were analyzed by IRMS. CN ratio of each sample was very similar to that of phytoplankton from literature cited. ${\delta}^{15}N$ of each sample was decreased during July. Mixing and dilution of nitrogen sources due to increment of influx by concentrated rainfall were considered as the main reason for the decline of ${\delta}^{15}N$. Based on analyzed ${\delta}^{15}N$ value of each sample, nitrogen source of Bughan river sample was presumed to come from soil. The nitrogen sources of Namhan river and Kyeongan stream samples seemed to be sewage or animal waste. Low ${\delta}^{15}N$ value in August (2012) seemed to be influenced by isotope fractionation due to the blooming of nitrogen-fixation blue-green algae (Anabaena spp.). Variation in ${\delta}^{15}N$ values particularly by blue-green algal bloom was considered the important factor for estimating the organic matter sources of phytoplankton.

• Magazine of the Korean Society of Agricultural Engineers
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• v.44 no.4
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• pp.39-50
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• 2002

Field experiment was performed to investigate water and nutrient mass balances in paddy field with groundwater irrigation from May to October, 2001. The total water inflow was about 1,183mm in which rainfall, overflow from upstream paddy, and groundwater irrigation accounted for 43, 30, and 27%, respectively. Notice that the precipitation of the study period was less than the average annual precipitation. The total drainage was almost balanced with the inflow and more than half of it was occurred by surface drainage. From the nutrient mass balance analysis, the T-P output (17.56kg/ha) was estimated slightly lower than the input (20.90kg/ha) and the T-N output (130.41kg/ha) was slightly greater than the input(129.24kg/ha). However, the difference was within the expectation and the nutrient mass was thought to be balanced considering uncertainties in field experiment and other activities not included in the study such as algae and soil microorganisms. The surface discharge of nutrient, which was about 10% of total nutrient output, was mainly affected by fertilization and rainfall runoff. Therefore, prudent surface drainage plan might be necessary particularly for the fertilization period to prevent degradation of receiving water quality. The study was performed under abnormally low rainfall compared to the average annual rainfall record, and further monitoring in diverse rainfalls and irrigation methods is recommended to estimate nutrient behavior in the paddy field more reasonably.

• Magazine of the Korean Society of Agricultural Engineers
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• v.44 no.4
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• pp.139-148
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• 2002

Pilot study was performed to examine the feasibility of the pond system for further polishing of treatment wetland effluent from December 2000 to June 2001. The wetland system used for the experiment was highly effective to treat the sewage during the growing season, but it was less effective and its effluent was still high to discharge to the receiving water body. Therefore, the wetland effluent may need further treatment to prevent water quality degradation. Pond system could be used to hold and further polish the wetland effluent during the winter season and ots feasibility was evaluated in this study. Additional water quality improvement was apparent in the pond system during winter season, and the pond effluent could be good enough to meet the effluent water quality standards if it is properly managed. Timing of the pond effluent discharge appears to be critical for pond system management because it is a closed system and whole water quality constituents are affected by physical, chemical, and biological pond environments. Once algae started to grow in mid-April, constituents in the pond water column interact each other actively and its control becomes more complicated. Therefore, upper layer of the pond water column which is clearer than the lower layer my need be discharged in March right after ice cover melted. In the experiment, water quality of the upper water column was markedly clear in March than ant other times probably because of freezing-thawing effect. The remaining lower water column could be further treated by natural purification as temperature goes up or diluted with better quality of wetland effluent for appropriate water uses. This study demonstrated the feasibility of pond system for subsequent management of wetland effluent during the winter season, however, more study is needed for field application.

• Journal of Photoscience
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• v.9 no.3
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• pp.45-48
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• 2002

Microbial rhodopsins, photoactive 7-transmembrane helix proteins that use retinal as their chromophore, were observed initially in the Archaea and appeared to be restricted to extreme halophilic environments. Our understanding of the abundance and diversity of this family has been radically transformed by findings over the past three years. Genome sequencing of cultivated microbes as well as environmental genomics have unexpectedly revealed archaeal rhodopsin homologs in the other two domains of life as well, namely Bacteria and Eucarya. Organisms containing these homologs inhabit such diverse environments as salt flats, soil, freshwater, and surface and deep ocean waters, and they comprise a broad phylogenetic range of microbial life, including haloarchaea, proteobacteria, cyanobacteria, fungi, and algae. Analysis of the new microbial rhodopsins and their expression and structural and functional characterization reveal that they fulfill both ion transport and sensory functions in various organisms, and use a variety of signaling mechanisms. We have obtained the first crystallographic structure for a photosensory member of this family, the phototaxis receptor sensory rhodopsin II (SRII, also known as phoborhodopsin) that mediates blue-light avoidance by the haloarchaeon Natronobacterium pharaonis. The structure obtained from x-ray diffraction of 3D crystals prepared in a cubic lipid phase reveals key features responsible for its spectral tuning and its sensory function. The mechanism of SRII signaling fits a unified model for transport and signaling in this widespread family of phototransducers.

• Journal of Species Research
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• v.11 no.3
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• pp.133-142
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• 2022

In 2020, 24 bacterial strains were isolated from algae, kudzu leaf, mud, pine cone, seashore sand, sea water, soil, tidal flat, and wetland from the Republic of Korea. Isolated bacterial strains were identified based on 16S rRNA gene sequences, and those exhibiting at least 98.7% sequence similarity with known bacterial species, but not reported in Korea, were highlighted as unrecorded species. These isolates were allocated to the phyla Bacteroidetes and Proteobacteria as unrecorded species in Korea. The four Bacteroidetes strains were classified into the families Chitinophagaceae, Flavobacteriaceae, and Sphingobacteriaceae (of the orders Chitinophagales, Flavobacteriales, and Sphingobacteriales, respectively). The 20 Proteobacteria strains belonged to the Aeromonadaceae, Marinobacter, Microbulbiferaceae, Enterobacteriaceae, Erwiniaceae, Morganellaceae, Yersiniaceae, Lysobacteraceae, Halomonadaceae, Moraxellaceae, Pseudomonadaceae, Steroidobacteraceae, Xanthomonadaceae, and Myxococcaceae (of the orders Aeromonadales, Alteromonadales, Cellvibrionales, Enterobacterales, Lysobacterales, Oceanospirillales, Pseudomonadales, Steroidobacter, Xanthomonadales, and Myxococcales). This study focused on the description of 24 unreported bacterial species in Korea in the phyla Bacteroidetes and Proteobacteria belonging to six classes.

• Journal of Food Hygiene and Safety
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• v.39 no.3
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• pp.191-208
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• 2024

The peptide-type hepatotoxins microcystins (MCs) and nodularin (NOD) are secondary metabolites produced by cyanobacteria. MCs and NOD can bioaccumulate in agricultural products through toxin-contaminated water, soil, and manure and can cause human health risks through the consumption of agricultural products. As interest in the contamination of agricultural products by MCs or NOD has recently emerged, occurrence studies based on various analysis methods for agricultural products have been conducted. However, studies on agricultural products are still insufficient compared to research on drinking water and seafood. In addition, research is primarily conducted on agricultural products grown in areas where green algae occur, but not on marketed products. In the present study, we review the physicochemical properties, toxicity, analysis methods, occurrence studies, and management status of MCs and NOD in agricultural products to build a foundation for systematic monitoring and safety management.

• Journal of Life Science
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• v.18 no.12
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• pp.1671-1678
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• 2008

We investigated the effect of the turbid water on the phytoplankton community in the 4 sites of Imha reservoir. The turbidity of water was proportional to the concentrations of $SiO_2$-Si. Therefore, as the turbidity of water grow, the concentration of $SiO_2$-Si increased. And the both the turbidity of water and the concentrations of $SiO_2$-Si were increased as the water run deep. The concentration of chlorophyll-a decreased as the depth of water increased. Seventy phytoplankton taxa were identified and the most abundant group was Chlorophyceae consisting of 32 taxa (46%), and Cyanophyceae and Bacillariophyceae consisted of 12 taxa (17%). And Euglenophyceae, Synulophyceae, Cryptophyceae and Dinophyceae consisted of 6 taxa (9%), 4 taxa (6%), 3 taxa (4%) and 1 taxon (1%), respectively in Imha reservoir. The concentrations of phytoplankton were increased according to the turbidity of water because of the high amount of organic nutrition which is presented with turbid water. And especially, the concentrations of nitrogen increased easily because of the weak binding to the soil particle. In conclusion, total nitrogen and $SiO_2$-Si flowed into the Imha reservoir with soil particle, and these inorganic nutritions affect the growth of algae.

• Korean Journal of Heritage: History & Science
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• v.53 no.2
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• pp.222-241
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• 2020

The Taereung Royal Tomb from the Joseon Dynasty is the tomb of Empress Munjeong, the second queen of King Jungjong, and it contains various types of stone artifacts. All of these stone artifacts were constructed using coarse- to medium-grained biotite granite. The major types of deterioration of the stone artifacts are identified as surface weathering and biological contaminants. Exfoliation (145 sculptures), granular decomposition (138 sculptures), and repair materials (156 sculptures), along with biological contaminant algae (154 sculptures), lichen (165 sculptures) and moss (97 sculptures), have a high occurrence frequency. In particular, it is deemed that immediate conservation treatment is required, as biological deterioration (algae) represents the most serious condition (grade 3 or higher in 94% of all stones), and it is thought that exfoliation and granulation decomposition are required for long-term conservation management. As a result of equo -tip hardness and ultrasonic measurement, more than 70% of stones were found to have very weak physical properties. Through hyperspectral analysis, organisms were shown to inhabit more than 80% of the surface of burial mound stone artifacts, and P (phosphorus), S (sulfur), Cl (chlorine), and Ca (calcium) were detected in this area. This is because Taereung Royal Tomb has been exposed to the outdoors for hundreds of years and has been weathered by physical, chemical, and biological factors. Therefore, among the stone artifacts in the Taereung Royal Tomb, those with high physical weathering grades are considered to require consolidation to reinforce them physically. Since organisms are highly likely to cause stone damage, they must be removed via dry and wet cleaning. In addition, in order to delay the reoccurrence of organisms following conservation treatment, it is necessary to regularly clean up the soil that has flowed into the burial mound, and to monitor conservation conditions over the long term.