• Microbiology and Biotechnology Letters
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• v.22 no.3
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• pp.233-239
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• 1994

The characteristics of the bacteriophage resistant Lactococcus lactis subsp. cremoris ATCC 11602-A1, the phage-resistant mutant of Lactococcus lactis subsp. cremoris ATCC 11602, was examined. Electron microscopic study of phage adsorption to A1 revealed that after 10 min. incubation of the host-phage mixture, A1 did not show phage adsorption, and after 60 min. did not show a real burst and the release of new phage particles which could be detected in the mixture of its parent strain and phage. However, the phage adsorption rate of A1 after SDS treatment increased to 98%. Moreover, when the cell walls from A1 and parent strain, and the polysaccharide(PS) and peptidoglycan(PG) of their cell wall were mixed with phage and incubated for 15 min., PS and PG from A1 did not bind phage, but only SD-treated cell wall bound phage, and the cell wall and PS of parent strain bound phage. Both A1 and parent strain treated with 0.2 N HCl-and 5% TCA(100$$C) did not bind phage. The results suggest that the phage receptor is still present in the cell wall of the A1, but a cell wall constituent hydrolyzed by SDS blocks phage adsorption by masking the phage receptor. It also suggests that the phage receptor of parent strain is associated with PS of the cell wall.

• Applied Chemistry for Engineering
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• v.28 no.2
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• pp.133-140
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• 2017

Increasing concerns on radioactive wastes have drawn much attention on the development of remediation technologies. Massive amounts of radioactive wastes generated from hospital and nuclear power plants were exposed to our environment. Although physicochemical removal methods were developed, an eco-friendly remediation method has not yet been demonstrated. Recently, an extremophilic bacterium has received much attention due to their extraordinary characteristics. Among them, Deinococcus radiodurans (D. radiodurans) strain was regarded as the best host organism for the removal of radioactive heavy metals and radionuclides, because of their superb characteristics like tolerance against the high level of radioactivity. In this article, we briefly introduced the extraordinary nature of D. radiodurans and also discussed the potential use of D. radiodurans strain for the removal of radioactive wastes.

• Journal of Plant Biotechnology
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• v.42 no.4
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• pp.298-311
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• 2015

Grape is one of the important fruit crops around the world, and exposed to disease and pests, and internal or environmental stresses in the vineyards. Breeding and cultivation of new varieties of high quality-grapes resistant to diseases and pests and tolerant to stresses are the most important steps in the grape production. However, conventional breeding has laborious and time-consuming procedures in maintaining and selecting seedlings in the fields. Development of molecular breeding technology through understanding of molecular mechanism of useful traits can be used as an alternative strategy to improve the efficiency of grape breeding program by cross hybridization in grape development programs. The completion of the grape genome sequencing project provided the way to discover the novel genes and to analyze their functions. Comparative genomics, transcriptomic analysis, and the genome-wide identification and analysis of useful genes as well as development of molecular marker for valuable traits could provide novel insights into fruit quality and the responses to diseases and stresses, and can be used as important information in molecular breeding programs for grape development.

• Proceedings of the KAIS Fall Conference
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• 2000.10a
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• pp.61-64
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• 2000

일반적으로 에어로졸 상의 고체입자에 대한 분리기술은 크게 전기집진기술과 여과집진기술, 습식기술 등으로 나눌 수 있다. 최근 연료의 탈황으로 인해 배출되는 먼지의 비저항성이 높아져 전기집진기술의 효율이 크게 떨어져 여과집진기술로 조금씩 대체되어가고 있다. 그러나 여과집진기술의 경우, Flow Gas 포집기작의 영향이 지배적이지 못한 l㎛ 미만의 입자들에 대한 제어가 효과적이지 못한 단점이 있다. 본 연구에서는 이러한 1㎛ 미만의 입자들에 대해 정전기력을 부여해서 전기적응집에 의한 입자성장을 유도하여 여과집진시에 필터 표면에 Dendrites Structure를 형성하게끔 유도하여 AP 증가율을 낮추고자 한다. 이에 따른 직접적인 효과는 탈진회수의 감소로 탈진시 소요되는 동력비의 감소와 탈진시 마모나 파손되는 여과포의 수명연장으로 실제 산업공정에 적용시 운전유지비의 감소효과를 꾀할 수 있을 것으로 사료된다.

• Journal of Plant Biotechnology
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• v.34 no.1
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• pp.61-68
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• 2007

To develop rice (Oryza sativa L.) cultivars to be planted on salt-affected sites, cell lines with enhanced proline content and resistance to growth inhibition by Azetidine-2-carboxylic acid (AZCA), a proline analogue, were screened out among calli irradiated with gamma ray of 50, 70, 90, and 120 Gy. The calli had been derived from embryo culture of the cultivar Donganbyeo. Selected AZCA resistant lines that had high proline accumulation were used as sources for selection of NaCl resistant lines. To determine an optimum concentration for selection of NaCl resistant lines, Donganbyeo seeds were initially cultured on the media containing various NaCl concentrations (0 to 2.5%) for 40 days, and 1.5% NaCl concentration was determined as the optimum concentration. One hundred sixteen salt-tolerant (ST) lines were selected from bulked 20,000 seeds of the AZCA resistant $M_{3}$ seeds in the medium containing 1.5% NaCl. The putative 33 lines ($M_{4}$ generation) considered with salt-tolerance were further analyzed for salt tolerance, amino acid and ion contents, and expression patterns of the salt tolerance-related genes. Out of the 33 lines, 7 lines were confirmed to have superior salt tolerance. Based on growth comparison of the entries, the selected mutant lines exhibited greater shoot length with average 1.5 times, root length with 1.3 times, root numbers with 1.1 times, and fresh weight with 1.5 times than control. Proline contents were increased maximum 20%, 100% and 20% in the leaf, seed and callus, respectively, of the selected lines. Compared to control, amino acid contents of the mutants were 24 to 29%, 49 to 143%, 32 to 60% higher in the leaf, seed and callus, respectively. The ratio of $Na^{+}/K^{+}$ for most of the ST-lines were lower than that of control, ranging from 1.0 to 3.8 for the leaf and 11.5 to 28.5 for the root, while the control had 3.5 and 32.9 in the leaf and root, respectively. The transcription patterns for the P5CS and NHXI genes observed by RT-PCR analysis indicated that these genes were actively expressed under salt stress. The selected mutants will be useful for the development of rice cultivar resistant to salt stress.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.27 no.1
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• pp.60-65
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• 1982

In order to observe the degree and response of drought-resistance and its physiological mechanism in barley and wheat seedling stage, 5 species (16 cultivars) were tested for the changes of nitrate reductase and protease activity and the accumulation of free proline, by being subjected to water stress by withholding watering for 8 days at 10 days (at the 3rd leaf stage) after emergence and by imposing water stress to the excised first leaf by polyethyleneglycol solution (osmotic potential, -20 bars) for 48 hours. The average rate of decrease of all cultivars was 42% in nitrate reductase activity and 73% in protease activity. But proline content in water stress was increased 10 folds more than that of control. The decrease4 rate of nitrate reductase activity in 5 species was in the order of wheat < rye < covered barley < naked barley < two-row barley: wheat being the lowest. The decreased rate of protease activity in 5 species was in the order of wheat > rye > two-row barley > covered barley > naked barley: wheat being the" heighest. The accumulated amount of free proline in 5 species by water stress was in the order of wheat > covered barley > rye > naked barley > two-row barley. And the increased ratio (folds) of free proline of water stress to control was in the order of rye(13) > wheat. covered barley(11) > naked barley(99) > two-row barley(7): rye being the highest. In terms of the enzymatic activity and the physiotically adaptive metabolism during the processing leading to drought-resistance, the degree of drought-resistance of 5 species to water stress at seedling stage was shown to be in the order of wheat > rye > covered barley > naked barley > two-row barley.

• Journal of Plant Biotechnology
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• v.45 no.3
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• pp.155-170
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• 2018

In this paper, mechanisms of gene editing technologies including ZFN, TALENS and CRISPR were briefly discussed with mutual advantages and disadvantages. Classification criteria of gene edited, site-directed mutagenesis (SDN) crops for regulatory purpose were also discussed. The number of studies using CRISPR technology was high and studies conducted on Arabidopsis thaliana and rice were highest, followed by tobacco, tomato, wheat, and corn. It has been applied to a variety of plants such as other grain crops, flower crops, vegetable crops, and fruit trees. The number of studies focused on practical application or commercialization in the future were also increasing yearly, and the scope of studies also expanded to include research on metabolic engineering for mass production of useful proteins or substances, development of disease resistant crops against viruses, bacteria, and fungi, abiotic environmental stressresistant crops, and increased yields. In addition to this, it was revealed that application range is becoming more diversified, including the development of parthenocarpic tomatoes, hybrid rice lines using male sterility and increased shattering resistance Brassica napus. It was also revealed that the number of CRISPR gene edited crops permitted by the USDA(APHIS) increases yearly, to be released in the international seed market soon.

• Korean Journal of Weed Science
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• v.30 no.2
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• pp.122-134
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• 2010

We investigated the levels of resistance and accumulation of terapyrroles, reactive oxygen species, lipid peroxidation, and antioxidative enzymes for reasons of growth reduction in herbicide-transgenic rice overexpressing Myxococcus xanthus, Arabidopsis thaliana, and human protoporphyrinogen oxidase (Protox) genes. The transgenic rice overexpressing M. xanthus (MX, MX1, PX), A. thaliana (AP31, AP36, AP37), and human (H45, H48, H49) Protox genes showed 43~65, 41~72 and 17~70-fold more resistance to oxyfluorfen, respectively, than the wild type. Among transgenic rice lines overexpressing Protox genes, several lines showed normal growth compared with the wild type, but several lines showed in reduction of plant height and shoot fresh weight under different light conditions. However, reduction of plant height of AP37 was much higher than other lines for the experimental period. On the other hand, the reduction of plant height and shoot fresh weight in the transgenic rice was higher in high light condition than in low light condition. Enhanced levels of Proto IX were observed in transgenic lines AP31, AP37, and H48 at 7 days after seeding (DAS) and transgenic lines PX, AP37, and H48 at 14 DAS relative to wild type. There were no differences in Mg-Proto IX of transgenic lines except for H41 and H48 and Mg-Proto IX monomethyl ester of transgenic lines except for MX, MX1, and PX. Although accumulation of tetrapyrrole intermediates was observed in transgenic lines, their tetrapyrrole accumulation levels were not enough to inhibit growth of transgenic rice. There were no differences in reactive oxygen species, MDA, ALA synthesizing capacity, and chlorophyll between transgenic lines and wild type indicating that accumulated tetrapyrrole intermediate were apparently not high enough to inhibit growth of transgenic rice. Therefore, the growth reduction in certain transgenic lines may not be caused by a single factor such as Proto IX, but by interaction of many other factors.

• Journal of fish pathology
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• v.10 no.2
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• pp.143-152
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• 1997

The effect of $\beta$-glucan as an immunostimulant to increase resistance to bacterial diseases by enhancing non-specific defense mechanism in rockfish (Sebastes schlegeli) was examined by oral and bath administration. After oral or bath administration with $\beta$-glucan, the injection challenges with Vibro ordalii, Staphylococcus epidermidis and Edwardsiella tarda were performed to assess $\beta$-glucan efficacy. After injection of V. ordalii, oral administration for 30 days with 1% $\beta$-glucan showed 25% of survival rate. But all control fish died within 3 days after the injection. After injection of S, epidermidis, oral administration group for 20 and 30 days showed a remarkably increased survival rate of 95%. But oral administration of $\beta$-glucan to rockfish did not induce protection against experimental E. tarda infection. $\beta$-Glucan bath administration with or without formalin-killed V. ordalii showed that no protection was observed at 10 days after challenge. The results show that $\beta$-glucan to rockfish was effective to increase survival rate of bacterial infections of S. epidermidis and V. ordalii but not against E. tarda.

• Microbiology and Biotechnology Letters
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• v.36 no.4
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• pp.268-275
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• 2008

In order to develop the multi-functional rhizobacteria that can exert positive effect on the growth of plants growing in the coastal sand dune located along East Coast of Korea, rhizospheral bacteria of 11 different plants from this area were isolated 1,330 rhizobacteria. Among these, 23 strains were able to produce auxin and had spectrum of antagonism toward various phytopathogenic microbes. To know the mechanism of this antifungal activity, these 23 strains were subjected to further analyses; 19 strains of these produced siderophore as determined by color reaction on CAS-blue plate, 4 strains produced antifungal cellulase as judged by color change on CMC-Congo red plate, 17 strains were able to utilized insoluble phosphate salts, also determined by clear zone formation on PVK medium. Identification of the strain was assigned to all 23 strains by l6s rDNA sequence analysed, and all were identified to be in the genus of Bacillus and Pseudomonas. One strain of these, denoted Pseudomonas fluorescens IB4-14, showed ACC deaminase activity which is known to be involved in the resistance of environmental stress such as salt and drought. Also, P. fluorescens IB4-l4 showed the germination stimulation and roots growth promoting activity on the in vivo assay of Lysimachia mauritiana Lam. (spoonleaf yellow loosestrife).