• Microbiology and Biotechnology Letters
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• v.27 no.4
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• pp.278-285
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• 1999

In order to use heat shock promoter for the detection of toxic substances, dnaK promoter was amplified from E. coli genomic DNA by using a polymerase chain reaction(PCR) followed by sequencing and sub-cloning into the multi-cloning site of the plasmid, pUCD615. The pUCD615 is a broad-host-range vector containing promoterless lux operon originated from V.fischeri. The recombinant plasmid was transfered to E. coli DH5$\alpha$ through electroporation. The recombinant E. coli showed several patterns of bioluminescent responses to ethanol stress. The bioluminescent E. coli also showed responses to other toxic substances including FeK3(CN)6, CdCl2, p-nitrophenol and HgCl2. The increases of RLU(Relative Light Unit) were observed at 100ppm of FeK3(CN)6, 10ppm and 100ppm and 100ppm of CdCl2, 1ppm of 10ppm of p-nitrophenol and at 1ppm of HgCl2.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.15 no.1
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• pp.8-15
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• 2010

An experiment was conducted to evaluate the biologically adverse effect of increased carbon dioxide in seawater on marine bacteria, Vibrio fischeri. We measured the bioluminescence and cell density at every 6 hours for 24 hours of the whole incubation period after exposing test microbes to a range of $CO_2$ concentration such as 380(Control), 1,000, 3,000, 10,000 and 30,000 ppm, respectively. Significant effect on relative luminescence(RLU) of V. fischeri was observed in treatments with $CO_2$ concentration higher than 3,000 ppm at t=12 h. However, the difference of RLU among treatments significantly decreased with the incubation time until t=24 h. Similar trend was observed for the variation of cell density, which was measured as optical density using spectrophotometer. The results showed that a significant relationship between $CO_2$ concentration and bioluminescence of test microbes was observed for the mean time. However, the inhibition of relative bioluminescence and also cell density could be recovered at the concentration levels higher than 3,000 ppm. The dissolved $CO_2$ can be absorbed directly by cell and it can decrease the intracellular pH. Our results implied that microbes might be adversely affected at the initial growing phase by increased $CO_2$. However, they could adapt by increasing ion transport including bicarbonate and then could make their pH back to normal level. Results of this study could be supported to understand the possible influence on marine bacteria by atmospheric increase of $CO_2$ in near future and also by released $CO_2$ during the marine $CO_2$ sequestration activity.

• Journal of Microbiology and Biotechnology
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• v.19 no.11
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• pp.1393-1400
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• 2009

A bacteriocin-producing strain PI80 was isolated from the gut of Penaeus indicus (Indian white shrimp) and identified as Streptococcus phocae PI80. The bacteriocin was purified from a culture supernatant to homogeneity as confirmed by Tricine SDS-PAGE. Reverse-phase HPLC analysis revealed a single active fraction eluted at 12.94 min, and MALDI-TOF mass spectrometry analysis showed the molecular mass to be 9.244 kDa. This molecular mass does not correspond to previously described streptococcal bacteriocins. The purified bacteriocin was named phocaecin PI80 from its producer strain, as this is the first report of bacteriocin production by Streptococcus phocae. The bacteriocin exhibited a broad spectrum of activity and inhibited important pathogens: Listeria monocytogenes, Vibrio parahaemolyticus, and V. fischeri. The antibacterial substance was also sensitive to proteolytic enzymes: trypsin, protease, pepsin, and chymotrypsin, yet insensitive to catalase, peroxidase, and diastase, confirming that the inhibition was due to a proteinaceous molecule (i.e., the bacteriocin), and not due to hydrogen peroxide or diacetyl. Phocaecin PI80 moderately tolerated heat treatment (up to $70^{\circ}C$ for 10 min) and resisted certain solvents (acetone, ethanol, and butanol). A massive leakage of $K^+$ ions from E. coli $DH5\alpha$, L. monocytogenes, and V. parahaemolyticus was induced by phocaecin PI80, as measured by Inductively Coupled Plasma Optical Emission Spectrometry (ICPOES). Therefore, the results of this study show that phocaecin PI80 may be a useful tool for inhibiting L. monocytogenes in seafood products that do not usually undergo adequate heat treatment, whereas the cells of Streptococcus phocae PI80 could be used to control vibriosis in shrimp farming.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.9
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• pp.955-960
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• 2008

We investigated and estimated at the characteristics of decomposition and mineralization of benomyl using a design of experiment(DOE) based on the general factorial design in an E-beam process, and also the main factors(variables) with benomyl concentration(X$_1$) and E-beam irradiation(X$_2$) which consisted of 5 levels in each factor was set up to estimate the prediction model and the optimization conditions. At frist, the benomyl in all treatment combinations except 17 and 18 trials was almost degraded and the difference in the decomposition of benomyl in the 3 blocks was not significant(p > 0.05, one-way ANOVA). However, the % of benomyl mineralization was 46%(block 1), 36.7%(block 2) and 22%(block 3) and showed the significant difference of the % that between each block(p < 0.05). The linear regression equations of benomyl mineralization in each block were also estimated as followed; block 1(Y$_1$ = 0.024X$_1$ + 34.1(R$^2$ = 0.929)), block 2(Y$_2$ = 0.026X$_2$ + 23.1(R$^2$ = 0.976)) and block 3(Y$_3$ = 0.034X$_3$ + 6.2(R$^2$ = 0.98)). The normality of benomyl mineralization obtained from Anderson-Darling test in all treatment conditions was satisfied(p > 0.05). The results of prediction model and optimization point using the canonical analysis in order to obtain the optimal operation conditions were Y = 39.96 - 9.36X$_1$ + 0.03X$_2$ - 10.67X$_1{^2}$ - 0.001X$_2{^2}$ + 0.011X$_1$X$_2$(R$^2$ = 96.3%, Adjusted R$^2$ = 94.8%) and 57.3% at 0.55 mg/L and 950 Gy, respectively. A Microtox test using V. fischeri showed that the toxicity, expressed as the inhibition(%), was reduced almost completely after an E-beam irradiation, whereas the inhibition(%) for 0.5 mg/L, 1 mg/L and 1.5 mg/L was 10.25%, 20.14% and 26.2% in the initial reactions in the absence of an E-beam illumination.

• Food Science and Preservation
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• v.20 no.5
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• pp.659-667
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• 2013

This study was performed to determine the effects of the blanching condition (immersion ratio 1:15 (w/v) for 3 min at $95^{\circ}C$, and solution containing 1% sodium chloride) and selected forming agents (dextrin DE=10, dextrin DE=20, ${\beta}$-cyclodextrin; each forming agents added 5%) on the phytochemical compounds and quality characteristics of Ligularia fischeri leaves. The moisture was not affected by the forming agent. The color of a, b and chroma values were low in the blanching treatment groups and were significantly lowest with ${\beta}$-cyclodextrin (CD). The polyphenol and flavonoid contents in the blanching treatment groups were higher than those in the non-blanching-treatment group. The ascorbic acid content was higher in the non-blanching-treatment group and was significantly highest in the group treated with dextrin (DE=10) whereas the blanching treatment groups showed lower dehydroascorbic acid content than the non-blanching-treatment group. The water absorption was higher in the non-blanching-treatment group and was significantly highest in the group treated with CD. The water solubility in the blanching treatment groups treated with dextrin (DE=20) and CD was higher than that in the blanching treatment group treated with DE=10. The total chlorophyll and chlorophyll a and b contents were high in the blanching treatment group treated with CD, and for the total carotenoid contents, the same tendency as that seen with the chlorophyll content was observed. With regard to the particle diameter, those in the blanching treatment groups were lower than that in the non-blanching-treatment group and was significantly lowest in the blanching treatment groups treated with DE=20 and CD. The result of SEM observation showed that the spray-dried powders in blanching treatment groups treated with the DE=20 and CD forming agents had uniform particle distribution.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.9 no.4
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• pp.13-23
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• 2006

The vascular plants of the studied area in the Mt. Bangjang was listed 422 taxa : 106 families, 299 genera, 372 species, 1 subspecies, 46 varieties and 3 forms. Based on the list of the rare plants by the Forest Research Institute, 5 taxa were recorded in the studied areas; Lilium distichum(Preservation priority order : No. 159), Tricyrtis dilatata (No. 97), Aristolochia contorta (No. 151), Prunus yedoensis (No. 110), Patrinia saniculaefolia (No. 122) and based on the list of Korean endemic plants, 9 taxa were recorded; Cephalotaxus koreana, Carex okamotoi, Populus tomentiglandulosa, Salix purpurea var. japonica, Prunus yedoensis, Forsythia koreana, Paulownia coreana, Weigela subsessilis, Patrinia saniculaefolia. Specific plant species by floral region were total 29 taxa; Prunus yedoensis in class V, 3 taxa(Acer palmatum, Asperula lasiantha, Lonicera subhispida ) in class III, 5 taxa(Lilium distichum, Potentilla dickinsii, Caryopteris incana, Patrinia saniculaefolia, Ligularia fischeri) in class II, 20 taxa(Ulmus parvifolia, Clematis patens, Aconitum jaluense, Ilex macropoda, Grewia biloba var. parviflora etc.) in class I. The naturalized plants in this site were 13 families, 31 genera, 36 species, 2 varieties, 38 taxa and naturalization rate was 9.0% of all 422 taxa vascular plants. Because of recent rapid increase of cars and people around here, analysis shows many naturalized plants and high naturalized ratio. And wild plants disturbing ecosystem like Ambrosia artemisiifolia var. elatior have been increasing. So, it needs continuing control and conservation measures on the plant ecosystem.

• Korean Journal of Environmental Biology
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• v.33 no.1
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• pp.45-52
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• 2015

Acute toxicity tests for 5 organic solvents were conducted using Euglena agilis carter (E. agilis), a Korean domestic organism. Organic solvents decreased the growth rate of E. agilis in a dose dependent manner. The toxicity to E. agilis was increased in the order of chloroform>acetone${\geq}$ethanol${\geq}$methanol>DMSO based on $EC_{50}$ values from growth test. Organic solvents also induced cell motility and morphological changes of E. agilis. Especially significant effects on the cell swimming velocity, motility, and compactness were observed for chloroform at the concentration of $EC_{50}$ calculated from 96 hr growth test. Overall, toxic responses of E. agilis to test substances are comparable to or more sensitive than D. magna, M. macrocopa and V. fischeri. Our study demonstrates that E. agilis can be a putative ecotoxicity test model organism to assess domestic water quality. Results obtained from this study can be applied to establish the standard test guidelines for ecotoxicity test using E. agilis.

• Food Science of Animal Resources
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• v.26 no.3
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• pp.402-409
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• 2006

Although microorganisms are, in fact, the most diverse and abundant type of organism on Earth, the ecological functions of microbial populations remains poorly understood. A variety of bacteria including marine Vibrios encounter numerous ecological challenges, such as UV light, predation, competition, and seasonal variations in seawater including pH, salinity, nutrient levels, temperature and so forth. In order to survive and proliferate under variable conditions, they have to develop elaborate means of communication to meet the challenges to which they are exposed. In bacteria, a range of biological functions have recently been found to be regulated by a population density-dependent cell-cell signaling mechanism known as quorum-sensing (QS). In other words, bacterial cells sense population density by monitoring the presence of self-produced extracellular autoinducers (AI). N-acylhomoserine lactone (AHL)-dependent quorum-sensing was first discovered in two luminescent marine bacteria, Vibrio fischeri and Vibrio harveyi. The LuxI/R system of V. fischeriis the paradigm of Gram-negative quorum-sensing systems. At high population density, the accumulated signalstrigger the expression of target genes and thereby initiate a new set of biological activities. Several QS systems have been identified so far. Among them, an AHL-dependent QS system has been found to control biofilm formation in several bacterial species, including Pseudomonas aeruginosa, Aeromonas hydrophila, Burkholderia cepacia, and Serratia liquefaciens. Bacterial biofilm is a structured community of bacterial cells enclosed in a self-produced polymeric matrix that adheres to an inert or living surface. Extracellular signal molecules have been implicated in biofilm formation. Agrobacterium tumefaciens strain NT1(traR, tra::lacZ749) and Chromobacterium violaceum strain CV026 are used as biosensors to detect AHL signals. Quorum sensing in lactic acid bacteria involves peptides that are directly sensed by membrane-located histidine kinases, after which the signal is transmitted to an intracellular regulator. In the nisin autoregulation process in Lactococcus lactis, the NisK protein acts as the sensor for nisin, and NisR protein as the response regulator activatingthe transcription of target genes. For control over growth and survival in bacterial communities, various strategies need to be developed by which receptors of the signal molecules are interfered with or the synthesis and release of the molecules is controlled. However, much is still unknown about the metabolic processes involved in such signal transduction and whether or not various foods and food ingredients may affect communication between spoilage or pathogenic bacteria. In five to ten years, we will be able to discover new signal molecules, some of which may have applications in food preservation to inhibit the growth of pathogens on foods.

• Korean Journal of Environment and Ecology
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• v.7 no.2
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• pp.91-103
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• 1994

The floristic characteristics and ecological conservation measures for the plant resources of the Tokyusan National Park. Chollapuk-do, Korea were discussed. The field works was done for three times in nine major areas from April to July, 1993. The total number of vascular plants in this area were summarized as 97 families, 297 genera, 469 species and 541 kinds. The nineteen kinds of artificially planted, twelve kinds of Korean endemics and sixteen kinds of Korean rare and endangered species in the area were revised and compiled in the list. The flora of the area were categorized into the Southern part of the Korean Region, where the species such as Quercus serrata. Fraxinus sieboldiana, Ilex macropoda, Lindera erythrocarpa, Lindera glauca, Rubus coreanus, Taxus cuspidata, Cephalotaxus koreana and Abies koreana were roled as major floristic components in the Korean Region and endemized in the southern part of Korea. The natural communities such as Adonis amurensis Community, Taxus cuspidata Community, Betula ermanii Community, Hemerocalis spp. Community, Rhododendron tschnoskii Community, Rhododendron schlippenbachii Community, Disporum ovale Community, Tricyrtis dilatata Community, and present natural distribution of Abies koreana, and swamp vegetation in Tumunsan areas, as well as upland grassland at the summit of Hyangchokpong were represented for their floristic values in the area. The fifteen kinds of medicinal plants such as Gastrodia elata, seven kinds of ornamental plants such as Adonis amurensis, and thirteen kinds of edible plants such as Ligularia fischeri are faced potentially in endangered from the outrageous collections by the local peoples. The Action Plan for the conservation management of the area which enables sustainable use by the local peoples must be established in the near future.

• Korean Journal of Plant Resources
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• v.19 no.5
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• pp.617-627
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• 2006

The wild plants of the studied area in the Gosan recreational forest was listed 327 taxa: 99 families, 252 genera, 289 species,1 subspecies, 34 varieties and 3 forms. Based on the list of the rare plants by the Forest Research Institute, 2 taxa were recorded in the studied areas; Lilium distichum (Presevation priority order: No. 159), Aristolochia contorta (No. 151) and based on the list of Korean endemic plants, 4 taxa were recorded; Cephalotaxus koreana, Carex okamotoi, Salix purpurea var. japonica, Weigela subsessilis. Specific plant species by floral region were total 21 taxa; 2 taxa (Asperula lasiantha, Lonicera subhispida) in class III, 4 taxa (Lilium distichum, Potentilla dickinsii, Caryopteris incana, Ligularia fischeri) in class II, 15 taxa (Hosta capitata, Alnus hirsuta, Ribes mandshuricum, Cayratia japonica, Vaccinium oldhami, etc.) in class I. The naturalized plants in this site were 12 families, 28 genera, 31 species, 1 varieties, 32 taxa and naturalization rate was 9.8%. So, wild plants disturbing ecosystem like Ambrosia artemisiifolia var. elatior have been increasing and it needs continuing control and conservation measures on the plant ecosystem.