• Korean Journal of Microbiology
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• v.55 no.3
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• pp.234-241
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• 2019

An intensive interaction between yeasts and insects has highlighted their relevance for attraction to food and for the insect's development and behavior. Yeast associated in the gut of insects secretes cellulase which aided in the food digestion (cellulose degradation). Three strains of cellulose-degrading yeast were isolated from the gut of adult grasshoppers collected in Gyeonggi Province, South Korea. The strains $ON22^T$, $G10^T$, and $G15^T$, showed positive cellulolytic activity in the carboxymethyl cellulose (CMC)-plate assay. The phylogenetic tree based on sequence analysis of D1/D2 domains of the large subunit rRNA gene and the internal transcribed spacer (ITS) regions revealed that the strains $ON22^T$ (100 and 98.4% sequence similarities in D1/D2 domains and ITS) and $G10^T$ (99.8 and 99.5% in D1/D2 domain and ITS region) were most closely related to the species Moesziomyces aphidis JCM $10318^T$; $G15^T$ (100% in D1/D2 domains and ITS) belongs to the species Moesziomyces antarcticus JCM $10317^T$, respectively. Morphology and biochemical test results are provided in the species description. Cellulase with its massive applicability has been used in various industrial processes such as biofuels like bioethanol productions. Therefore, this is the first report of the cellulolytic yeast strains $ON22^T$, $G10^T$, and $G15^T$ related to the genus Moesziomyces in the family Ustilaginaceae (Ustilaginales), in Korea.

• Korean Journal of Heritage: History & Science
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• v.49 no.2
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• pp.56-69
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• 2016

Flame resistant treatment has been applied since 1973 for fire prevention in historical wooden buildings, but several problems, such as whitening and discoloration are constantly occurring in some Dancheong, in spite of evaluation criteria. It is supposed that these phenomena are caused by the stability issue of flame retardant, Dancheong production methods, the residue of chemicals, which were applied in the past, building location environments, etc., but no evaluation and cause inspection has been performed. Therefore, this study aims to verify the effect of flame retardant on Dancheong by producing Pseudo-samples and setting spatial and temporal environment conditions. Pseudo-samples of Dancheong were produced using three methods; the method specified in the Standard Specification of Properties; the method, which is generally used in the site and the traditional method. For different environment conditions of pseudo-samples, the areas were classified into a coastal area and an inland area and the places were classified into a sunny place and a wetland. After applying a flame retardant, annual variations were inspected for 12 months and change aspects were observed through scan and regular observation. In annual variation inspection, various variations like whitening, decolorization, dissolution and exfoliation were found and especially, whitening was most dominant. When the effect of flame retardant depending on the production methods was analyzed, whitening occurred in all the three production methods. It is supposed that this is because calcium(Ca) was contained in the coloring material of each production method and it reacted with phosphorous(P) of flame retardant. When the effect of flame retardant depending on the environment conditions was analyzed, whitening occurred more in the coastal area than in the inland area and it reduced in the building in a sunny place, which was constructed using the traditional method. It is supposed that this results from the humidity change and the difference of glue used in each production method. In conclusion, for using a flame retardant containing phosphorous(P), there is a need to check if calcium components including Oyster Shell White were used in Dancheong in advance and to conduct various preliminary studies on place conditions and Dancheong construction conditions.

• Journal of Korean Society of Forest Science
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• v.108 no.3
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• pp.290-295
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• 2019

This study was carried out to investigate the possibility of establishing a reproductive system for the seed of Pedicularis hallaisanensis, which is in the endangered wild species II class in Korea. The seed of P. hallaisanensis is egg-shaped, and the seed coat is dark brown. The embryo was identified as a dwarf type by the seed section. The seed length was $0.47{\pm}0.07mm$, width $0.16{\pm}0.006mm$, and thickness $0.12{\pm}0.01mm$. The weight of one seed was $0.0003{\pm}0.0001mg$, and 1000 seeds weighed $4.59{\pm}0.02mg$. The degree of seed viability was 75.33% by the tetrazolium (TZ) assay. The highest germination rate of P. hallaisanensis seed was 71% after 4 weeks of storage at $4^{\circ}C$. However, the germination rate tended to decrease gradually over a longer storage period. The germination rates after 6 or 8 weeks of storage at $4^{\circ}C$ were 64% and 60%, respectively. We used two host plants, Artemisia princeps and Dendranthema zawadskii, to determine the effect of host plants on P. hallaisanensis seed germination. The germination of P. hallaisanensis mixed with A. princeps or D. zawadskii started at 53.5 and 62.5 days after sowing, respectively. We did not find any germination 164 days postsowing with both host plants. When A. princeps and D. zawadskii were used as host plants for P. hallaisanensis seed germination, P. hallaisanensis seed germination rates were 45.5% and 19.5%, respectively. The average time to germination was 70.2 days for A. princeps, and 46.8 days for D. zawadskii.

• Journal of Plant Biotechnology
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• v.46 no.3
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• pp.228-235
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• 2019

Apple (Malus pumila) is one of the most economically important fruits in Korea. but virus infection has decreased the sustainable production of apples and caused serious problems such as yield loss and poor fruit quality. Virus or viroid infection including apple chlorotic leaf spot virus (ACLSV), apple stem pitting virus (ASPV), apple stem grooving virus (ASGV), apple mosaic virus (ApMV) and apple scar skin viroid (ASSVd) have been also reported in Korea. In many cases, as apple gets infected with virus and viroid with no specific symptoms, the damage and symptoms caused by the viruses are not detected. In our research, viruses in the rootstock were eliminated for a virus-free apple dwarfing rootstock of M.9 and M.26. The virus elimination methods were apical meristem culture, thermotherapy ($37^{\circ}C$, 6 weeks) and chemotherapy($Ribavirin^{(R)}$). The detection of apple viruses was accomplished by Enzyme-linked Immuno-Sorbent Assay (ELlSA) and reverse transcription-polymerase chain reaction (RT-PCR). RT- PCR method was 10 ~ 30% more sensitive than the ELISA method. The efficiency of virus elimination was enhanced in apical meristem culture method. The acquisition rate of virus-free apple dwarfing rootstocks was 30 ~ 40% higher in apical meristem culture. After the meristem culturing of M.9, the infection ratio of ACLSV, ASPV and ASGV was 45%, 60% and 50%, respectively. In the apple dwarfing rootstock of M.26, the infection ratio of ACLSV, ASPV and ASGV was 40%, 55% and 55%, respectively. Based on this study, the best method for the production of virus-free apple dwarfing rootstocks was the apical meristem culture.

• Korean Journal of Ecology and Environment
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• v.52 no.3
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• pp.210-220
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• 2019

Population growth and the increase of energy consumption due to civilization caused global warming. Temperature on the Earth rose about $0.7^{\circ}C$ for the last 100 years, the rate is accelerated since 2000. Temperature is a factor, which determines physiological action, growth and development, survival, etc. of the plant together with light intensity and precipitation. Therefore, it is expected that global warming would affect broadly geographic distribution of the plant as well as structure and function ecosystem. In order to understand the effect of global warming on the ecosystem, a study about the effect of temperature rise on germination and growth in the plant is required necessarily. This study was carried out to investigate the effects of experimental warming on the germination and growth of two oak species(Quercus mongolica and Q. serrata) in temperature gradient chamber(TGC). This study was conducted in control, medium warming treatment($+1.7^{\circ}C$; Tm), and high warming treatment ($+3.2^{\circ}C$; Th) conditions. The final germination percentage, mean germination time and germination rate of two oak species increased by the warming treatment, and the increase in Q. serrata was higher than that in Q. mongolica. Root collar diameter, seedling height, leaf dry weight, stem dry weight, root dry weight, and total biomass were the highest in Tm treatment. Butthey were not significantly different in the Th treatment. In the Th treatment, Q. serrata had significantly higher H/D ratio, S/R ratio, and low root mass ratio (RMR) compared with control plot. Q. mongolica had lower RMR and higher S/R ratio in the Tm and Th treatments compared with control plot. Therefore, growth of Q. mongolica are expected to be more vulnerable to warming than that of Q. serrata. The main findings of this study, species-specific responses to experimental warming, could be applied to predict ecosystem changes from global warming. From the result of this study, we could deduce that temperature rise would increase germination of Q. serrata and Q. mongolica and consequently contribute to increase establishment rate in the early growth stage of the plants. But we have to consider diverse variables to understand properly the effects that global warming influences germination in natural condition. Treatment of global warming in the medium level increased the growth and the biomass of both Q. serrata and Q. mongolica. But the result of treatment in the high level showed different aspects. In particular, Q. mongolica, which grows in cooler zones of higher elevation on mountains or northward in latitude, responded more sensitively. Synthesized the results mentioned above, continuous global warming would function in stable establishment of both plants unfavorably. Compared the responses of both sample plants on temperature rise, Q. serrata increased germination rate more than Q. mongolica and Q. mongolica responded more sensitively than Q. serrata in biomass allocation with the increase of temperature. It was estimated that these results would due to a difference of microclimate originated from the spatial distribution of both plants.

• Journal of Applied Biological Chemistry
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• v.62 no.3
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• pp.287-292
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• 2019

Pseudomonas tolaasii causes brown blotch disease on the oyster mushroom (Pleurotus ostreatus). Various pathogenic strains of P. tolaasii were isolated and divided into three subtypes, $P1{\alpha}$, $P1{\beta}$, and $P1{\gamma}$. For phage therapy, bacteriophages against to these subtype strains were applied to mushroom cultivation and very successful to prevent from the disease. In this study, bacteriophages were isolated against the representative strains of subtype pathogens and their polyclonal antibodies were synthesized to investigate structural relationship among capsid proteins of phages. Phage preparations over $10^{10}pfu/mL$ were injected to rabbit thigh muscle and polyclonal antibodies were obtained after three times of boost injection. Titers of the antibodies obtained were over $2{\times}10^7Ab/mL$ for the phage ${\phi}6264$, $1{\times}10^6Ab/mL$ for the phage ${\phi}HK2$, and $1{\times}10^7Ab/mL$ for the phage ${\phi}HK19$ and phage ${\phi}HK23$. High specific activities were observed between antibodies and the corresponding bacteriophages. Some cross-reactivities between the antibodies and non-corresponding bacteriophages were also measured. Antibody $Ab{\phi}6264$ inactivated all phages of $P1{\alpha}$ subtype and only phage ${\phi}HK16$ among $P1{\beta}$ subtype phages. Antibody $Ab{\phi}HK23$ of $P1{\gamma}$ subtype neutralized all phages of $P1{\beta}$ subtype as well as the phage ${\phi}HK23$, showing the widest phage-inactivation range. When the structural-similarity studies of phages were investigated by using phage antibodies, closeness obtained by phylogenetic analysis of 16S rRNA genes of pathogenic strains were quite different from that of polyclonal antibody-specific structural similarity of phage capsid proteins. In conclusion, there is weak correlation between the host strain specificity of bacteriophage and its capsid structural similarity measured by phage antibodies.

• Journal of Food Hygiene and Safety
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• v.34 no.3
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• pp.219-226
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• 2019

This study was conducted to understand the overall status of the monitoring program for pesticide residues in foods of South Korea. Further propositions for its improvement were made, and from this study, the status on this program can be summarized as follows. In South Korea, the Ministry of Food and Drug Safety (MFDS) is responsible for overall control of pesticide residue monitoring. Depending on the time of monitoring (sampling at distribution or production step), the government agency responsible for monitoring is different: MFDS, Regional Offices of Food and Drug Safety and local governments are responsible for monitoring of foods at the distribution step, while the National Agricultural Products Quality Management Service (NAQS) and local governments are responsible for monitoring of foods in the production step (partially at sale and distribution steps). According to purpose of monitoring, domestic monitoring programs could be divided into two types: MFDS's "Residue Survey" and NAQS's "National Residue Survey" are conducted mainly for risk assessment purposes and various monitoring programs by the Regional Offices of Food and Drug Safety and local governments are conducted mainly for regulation purposes. For imported foods, monitoring should be conducted at both steps of customs clearance and distribution: the MFDS and the Regional Offices of Food and Drug Safety are responsible for the former, and for the latter, local governments are also responsible. However, it appeared that systematic and consistent monitoring programs are not being conducted for imported foods at the distribution step. Based on the information described above and more detailed information included in this paper, the following proposals for improving the monitoring program were forwarded: i) further clarification of monitoring program purpose, ii) strengthening of the monitoring program for imported foods, iii) providing the public with monitoring results by publication of an annual report and database. It is thought that exhaustive review on the pesticide residue monitoring program and efforts for its improvement are needed in order to assure both food safety and the success of the recently begun positive list system (PLS).

• Journal of Plant Biotechnology
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• v.46 no.1
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• pp.22-31
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• 2019

The objective of this study was to investigate the suitable parts for callus induction and optimal concentrations of growth regulators contained in the medium affecting shooting and rooting Echeveria laui and Echeveria elegans for in vitro mass production. To determine the suitable plant parts for callus induction, the leaves were divided into upper, medium and bottom parts and cultured on MS medium at different concentrations with $0{\sim}2mgL^{-1}\;NAA$ and $0{\sim}4 mgL^{-1}BA$. The upper and middle parts of leaves both showed 100% callus formation rate with $NAA\;1\;mgL^{-1}$ and $BA\;1\;mgL^{-1}$ treatment in E. laui. The middle parts of leaves showed 83.3% callus formation rate at $NAA\;2\;mgL^{-1}$ and BA 4 mgL-1 treatment in E. elegans. The shoot induction rate from callus was highest at $NAA\;0.1\;mgL^{-1}$ and $BA\;3\;mgL^{-1}$ treatment in E. laui and $NAA\;0.3\;mgL^{-1}$ in E. elegans. In addition, the number of shoots formation was 10.4 shoots high in $NAA\;1\;mgL^{-1}$ and $BA\;1\;mgL^{-1}$ treatment in E. laui and 12.0 shoots in most effective $NAA\;1\;mgL^{-1}$ and $BA\;0.1\;mgL^{-1}$ treatment in E. elegans. In the case of acclimatization of regenerated plant, growth characteristics did not show any significant difference (35 ~ 55%) shading with respect to the different ratio of substrate mixture, and it was determined that would be appropriate considered plant height and appearance preference of E. laui and E. elegans. It was established that the optimization of culture condition was responsible for the mass propagation in vitro cultures of E. laui and E. elegans.

• Journal of Applied Biological Chemistry
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• v.62 no.1
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• pp.25-30
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• 2019

This study investigated the quality changes in whole super sweet corn during thermal processing to extend its shelf-life. To minimize the reduction of unique texture of whole sweet corn after the sterilization, the alcohol sanitation applied and the cold point of a whole corn ear was determined using a computer simulation. The cold point was located between the corn kernel and the cob. The microorganisms on the surface of sweet corn were reduced by more than 1 log CFU/g after alcohol sanitation, then the whole corn was treated to satisfy the degree of sterilization ($F_{121.1}=4$). The quality of sterilized sweet corn was compared with the control that was treated with steaming. The quality changes of sterilized sweet corn during storage were monitored for 9 months at $25^{\circ}C$. The hardness was maintained within 30% of its initial value. The minimum of hardness was $464.50{\pm}103.35g$ and maximum of hardness was $514.50{\pm}81.83g$. The differences in the sugar content among the samples were found, but the sugar content of corn kernel remained within 30% of the control, ranging from $28.83{\pm}1.05$ to $34.36{\pm}0.42%$. The yellowness was higher than that of control by 5%. The maximum value of yellowness was $34.36{\pm}0.42$. The general bacteria and molds and yeasts in corn kernel stored at $25^{\circ}C$ were not detected after 9 months of storage at $25^{\circ}C$. Therefore, in this study, we have demonstrated that the thermal sterilized method extends the shelf-life of whole sweet corn with minimizing its quality changes over 6 months in room temperature.

• Journal of Bio-Environment Control
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• v.28 no.2
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• pp.166-171
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• 2019

This study was conducted to investigate the effect of gaseous chlorine dioxide ($ClO_2$) concentration and treatment method for maintaining marketability in strawberries 'Maehyang' for export. After harvesting strawberry colored with $60{\pm}5%$ of the skin, and the gaseous $ClO_2$ was applied as four treatments in the cold store set with $10^{\circ}C$ which were as follows: i) non-treatment (Control), ii) $0.2mg{\cdot}L^{-1}$ for 30 minutes, iii) $0.4mg{\cdot}L^{-1}$ for 30 minutes, and iv) continuously exposed at $0.4mg{\cdot}L^{-1}$ during the storage period. Weight loss, firmness, soluble solids content, color, incidence of gray mold, and quality grade of strawberries were investigated every 3 days during 16 days storage in cold store. The weight loss was consistently high at $0.2mg{\cdot}L^{-1}\;ClO_2$ treatment, and the weight loss was lower than other treatments when gaseous $ClO_2$ was continuously treated. Firmness was significantly higher at 0.2 and $0.4mg{\cdot}L^{-1}$ $ClO_2$ treatment on the 13th day of storage. Soluble solids content tended to below in continuous gaseous $ClO_2$ treatment. The colors showed no tendency as affected by concentrations and treatment methods of gaseous $ClO_2$. No gray mold was observed in the continuous gaseous $ClO_2$ treatment until the 13th day of storage. The quality grade was lower in gaseous $ClO_2$ treatment group than in the control. As a result, it was possible to decrease the weight loss and the incidence of gray mold by continuously treating the gaseous $ClO_2$ to strawberry 'Maehyang' for export during the storage period after harvest. However, further research is needed on method to maintain quality grades of fruits.