• The Korean Journal of Pesticide Science
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• v.11 no.2
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• pp.67-71
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• 2007

Nobel series of 5-benzyloxymethyl-3-(thiophen-5-yl)-1,2-isoxazoline derivatives were designed and synthesized. The herbicidal activities of these compounds to main dominant weeds to these compounds were evaluated in pot tests that simulated rice paddy conditions. Most of the compounds showed high herbicidal activity to main dominant weeds occurring in rice field without the serious rice injury.

• Journal of Plant Biotechnology
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• v.37 no.4
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• pp.556-561
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• 2010

Lactoferrin is an 80-kDa iron-binding glycoprotein that is found in high concentrations in human milk. Human lactoferrin (hLF) has several beneficial biological activities including immune system modulation and antimicrobial activity. In the present study, we devolved a method of hLF expression through introducing the hLF gene construct into Oriza sativa cv. Nakdong using the Agrobacterium-mediated transformation system. The expression of the hLF gene under the control of the rice glutelin promoter was detected in the seeds of transgenic rice plants. Transformed rice plants were selected on media containing herbicide(DL-phosphinothricin) and the integration of hLF cDNA was confirmed by Southern blot analysis. The expression of the full length hLF protein from the grains of transgenic rice plants was verified by Western blot analysis. The lactoferrin expression levels in the transformed rice grains determined by enzyme-linked immunosorbant assay accounted for approximately 1.5% of total soluble protein. Taken together, these data indicate that rice grains expressing hLF can be directly incorporated into infant formula and baby food.

• Plant Biotechnology Reports
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• v.2 no.1
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• pp.47-58
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• 2008

To select agronomically useful transgenic plants, a large number of transgenic events are initially produced, gene transfer confirmed, and advanced to obtain homozygous lines for testing in field trials. Direct in planta assays for identifying the transgene carriers in the segregating progeny are based on the activity of selectable marker gene and are easy, simple and inexpensive. For this purpose, expression of bar gene as measured by tolerance to damage by glufosinate ammonium, the active ingredient in the herbicide BASTA, was investigated. Dose damage curves were generated by leaf paint tests with BASTA on four genotypes of sorghum. Transgenic plants were characterized in terms of sensitivity to the concentration of glufosinate ammonium. In transgenics, symptoms of BASTA swab tests at different growth stages and PCR analysis for cry1B were carried out and correlated. Germination tests could not be employed for large scale evaluation of transgenic progeny because of mortality of tolerant seedlings after transplantation to soil. Based on the above findings, a simple, inexpensive, time-saving, two-step scheme for effective evaluation of transgenics and their progeny containing bar gene as selection marker using BASTA swab tests is described.

• Korean Journal of Weed Science
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• v.2 no.1
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• pp.13-19
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• 1982

The effect of metolachlor [2-chloro-N-(2-ethyl 1-6-methylphenyl)-N-(2-methoxy-l-methylethyl)-acetamide] on starch, sugar and protein content in relation with ${\alpha}$-amylase activity, and its interaction with GA in the germinating stage of rice were determined. The distinctive phytotoxic symptom was the failure of the primary leaf of rice to break the coleoptile. An inhibitory effect of metolachlor was nullified by the external application of GA $10^{-3}$M. A significantly slower starch degradation accompanying the lower content of sugars was observed in the gain of the metolachlor treated seedlings. Further, the total ${\alpha}$-amylase activity was significantly lower in the grain of rice seedlings treated with metolachlor than that of the untreated one, and the lower total ${\alpha}$-amylase activity could be due to an inhibition of ${\alpha}$-amylase formation.

• Korean Journal of Weed Science
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• v.16 no.4
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• pp.327-336
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• 1996

This study was conducted to investigate the content of antioxidant and GST activity of the oxyfluorfen-tolerant and -susceptible rice cultivars with barnyardgrass, a typical susceptible weed in accordance by oxyfluorfen treatment. The content of vitamin C was higher in the tolerant rice cultivar than in the susceptible rice cultivar and barnyardgrass. The contents of vitamin E, carotenoid, glutathione(GSH, GSSG, total glutathione) were not different between the tolerant and susceptible plants. In the case of the content of vitamin C due to the treatment of oxyfluorfen, the tolerant rice cultivars, Hawon and Baru decreased less than the susceptible rice cultivars and barnyardgrass. After the treatment of oxyfluorfen the contents of vitamin E and GSH in the tolerant rice cultivars were higher than in the susceptible rice cultivars or barnyardgrass. But in the content of carotenoid was greater in the tolerant rice cultivars than in the susceptible rice cultivars but they didn`t have any difference in comparison with the susceptible barnyardgrass. And there was no difference in the content of GSSG between the tolerant and susceptible plants. When CDNB or oxyfluorfen were used as substrate, the GST activity, was higher in the tolerant rice cultivars than in the susceptible rice cultivars or batnyardgrass. After the treatment of oxyfluorfen the GST activity was not induced in the rice, but was induced in the barnyardgrass. Even after the treatment of acifluorfen, bifenox and oxadiazon the GST activity was not induced in the rice cultivars.

• Korean Journal of Medicinal Crop Science
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• v.12 no.5
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• pp.360-365
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• 2004

Rehmannia glutinosa shows a high level of resistance to the non-selective herbicide paraquat. To characterize the antioxidant enzyme system of R. glutinosa, we comparatively examined the responses of antioxidant enzymes to UV, wounding and a general elicitor yeast extract in R. glutinosa and soybean. The levels of enzyme activities of the two plant species were drastically different between those per fresh weight (general activity) and per protein (specific activity) bases. The general activities of superoxide dismutase (SOD), peroxidase (POX), catalase (CAT), and glutathione reductase (GR) were lower, but that of ascorbate peroxidase (APX) was higher in R. glutinosa than in soybean. The specific activities of the enzymes, however, were about two- to seven-fold higher in R. glutinosa than in soybean, except that of CAT, which was about 12-fold higher in soybean. The general and specific enzyme activities of R. glutinosa relative to those of soybean showed a consistent increase in responses to the stresses only in SOD. The specific activities of SOD and APX were higher in R. glutinosa in all stress treatments. The results might suggest a relatively higher contribution of SOD and APX to the stress tolerance.

• Bulletin of the Korean Chemical Society
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• v.28 no.12
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• pp.2303-2309
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• 2007

Expressed protein ligation (EPL) technique, joining recombinantly expressed proteins to polypeptides, has been widely adopted for addressing various biological questions and for drug discovery. However, joining two recombinant proteins together is sometimes difficult when proteins are expressed insoluble and unrefoldable, because ligation-active proteins via intein-fusion are obtainable when they are folded correctly. We overcame this limitation coexpressing target protein with additional methionine aminopeptidase (MAP) which enhances removal of the initiation methionine of recombinantly expressed protein. Our approach demonstrated that two domains of 46 kDa 5-Enolpyruvylshikimate-3-phosphate (EPSP) synthase, a target of herbicide glyphosate, were successfully joined by native chemical ligation, although its C-terminal domain was expressed as an inclusion body. The intein-fused N-terminal fragment of EPSP synthase (EPSPSN, residues 1-237) was expressed and the ligation-active thioester tagged N-terminal fragment (EPSPSN-thioester) was purified using a chitin affinity chromatography and mercapto-ethanesulphonate (MESNA) as intein thiolysis reagent. Its Cterminal fragment (EPSPSC, residues Met237-238CYS-427), expressed as an inclusion body, was prepared from an additional MAP-expressing strain. Protein ligation was initiated by mixing ~1 mM of EPSPSN-thioester with ~2 mM of EPSPSCCYS (residues 238CYS-427). Also we found that addition of 2% thiophenol increased the ligation efficiency via thiol exchange. The ligation efficiency was ~85%. The ligated full-length EPSP synthase was dissolved in 6 M GdHCl and refolded. Circular dichroism (CD) and enzyme activity assay of the purified protein showed that the ligated enzyme has distinct secondary structure and ~115% specific activity compared to those of wild-type EPSP synthase. This work demonstrates rare example of EPL between two recombinantly expressed proteins and also provides hands-on protein engineering protocol for large proteins.

• BMB Reports
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• v.33 no.3
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• pp.195-201
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• 2000

A human gene has been reported that may encode the enzyme acetohydroxyacid synthase. Previously this enzyme was thought to be absent from animals although it is present in plants and many microorganisms. In plants, this enzyme is the target of a number of commercial herbicides and the use of these compounds may need to be reassessed if the human enzyme exists and proves to be susceptible to inhibition. Here we report the construction of several plasmid vectors containing the cDNA sequence for this protein, and their expression in Escherichia coli. High levels of expression were observed, but most of the protein proved to be insoluble. The small amounts of soluble protein contained little or no acetohydroxyacid synthase activity. Attempts to refold the insoluble protein were successful insofar as the protein became soluble. However, the refolded protein did not gain any acetohydroxyacid synthase activity. In vivo complementation tests of an E. coli mutant produced no evidence that the protein is active. Incorrect folding, or the lack of another subunit, may explain the data but we favor the interpretation that this gene does not encode an acetohydroxyacid synthase.

• Korean Journal of Weed Science
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• v.32 no.2
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• pp.133-138
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• 2012

This study was conducted to investigate the herbicidal activity against resistant biotype on sulfonylurea (SU) herbicides such as Scirpus juncoides and Monochoria vaginalis at the glasshouse and paddy rice cultivation area. In order to investigate resistance breakability against SU-resistanted annual weeds, new rice herbicides containing tefuryltrione [p-hydrophenyl pyruvate dioxygenase (HPPD) inhibitor] were tested. In both lab test and field experiment, tefuryltrione mixture, 4-HPPD inhibitor had shown excellent efficacy with a bleaching on the leaves of resistant annual weeds at early time after treatment and showed excellent persistance. Especially, tefuryltrione mixture had shown excellent controlling effect on annual and perennial SU-resistant S. juncoides in the regional field experiment. In phytotoxicity test, this tefuryltrione mixture had shown good selectivity to common rice species.

• The Korean Journal of Pesticide Science
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• v.11 no.1
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• pp.52-58
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• 2007

ALA (5-aminolevulinic acid) has been proposed as a tetrapyrrole-dependent photodynamic herbicide and insecticide by the action of the protoporphyrinogen IX oxidase (Protox IX). The present study was conducted to determine growth responses of plant and insects to ALA, biodegradable biopesticidal substance. In the paddy condition experiment, plant height and shoot fresh weight of barnyardgrass (Echinochloa crus-galli) was more reduced by ALA than rice plants, even though both plant species show great phytotoxicity. Hairy crabgrass (Digitaria sanguinalis), a monocot weed, was more sensitive to ALA at 5mM under upland condition when ALA applied on the foliage, compared with soybean (Glycine max) as a dicot crop. ALA solutions were tested for their insecticidal and larvicidal activities against Spodaptera exigua (Hubner) and Tetranychus urticae Koch. by foliar application and leaf-dipping method. The result showed higher insecticidal activity of ALA at 10mM and its mixture with insecticide luferon against S. exigua. Strongest insecticidal activity against T. urticae was observed from the ALA solution at 10mM 72 days after application. This results show that ALA solution had potent herbicidal and insecticidal activities against agricultural pests even though their activities were lower than those of synthetic pesticides.