• Korean Journal of Weed Science
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• v.14 no.1
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• pp.8-15
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• 1994

The mode of safening action and potency of the 1, 8-naphthalic anhydride(NA) were investigated in corn(Zea mays) and soybean(Glycine max) treated with herbicide bensulfuron[2-{{{{{(4,6-dimethoxy-2-pyrimidinyl)amino}carbonyl}amino}sulfonyl}methyl}benzoic acid] and imazaquin[2-{4,5-dihydro-4-methyl-4-(1-methylethyl)-5-oxo-1H-imidazol-2-yl} 3-quinolinonecarboxylic acid]. Seed dressing with 0.2%(w/w) NA showed successful protection in corn against injury from herbicide bensulfuron and imazaquin but not in soybean. Safening factors of NA against bensulfuron and imazaquin were 10.2 and 5.0, respectively, in corn, while they were both 1.3 in soybean. In vivo, Glutathione-S-transferase(GST) activity of NA-treated corn and soybean increased 1.8-and 1.3-fold, respectively, but the activity was not affected by the herbicides in vitro. Acetolactate synthase(ALS) levels of NA-treated corn was increased 1.3-fold, but not changed in soybean. Tolerance of ALS activity to the herbicides was slightly greater in ALS obtained from NA-treated corn than that from the untreated, whereas the difference was not found in soybean. A significant increase of ACCase due to NA occurred in corn, but not in soybean. The herbicides did not affect in vitro ACCase activity.

• The Korean Journal of Ecology
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• v.17 no.2
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• pp.143-148
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• 1994

The relationships between microbial activity and physico-KDICical characteristics of soils were investigated in three golf courses of Kwanak, Gold and Korea Country Clubs, with different open years. The soil samples were collected in tee, fairway and rough. There were ranges of 4.80-5.55 in pH, $25.55-98.50{\mu}S$ / cm in conductivity, 10.96-16.73% in moisture content, 0.18-0.36g / g in water holding capacity, 3.68-5.39% in organic matter, and 0.10-0.25% in total nitrogen. Dehydrogenase activity(DHA) as an index of soil microbial activity was determined. DHA values of soil were $69.83-314.43{\mu}$g / g in three courses and showed the order of Kwanak>Gold>Korea Country Club with open year. This indicates that DHA was affected by several fertilizer treatments rather than herbicide and pesticide treatments. DHA was significantly different with golf clubs as well as golf courses and positively correlated with water holding capacity and total nitrogen.

• The Korean Journal of Pesticide Science
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• v.5 no.1
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• pp.36-45
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• 2001

This study was conducted to search new target enzymes of novel herbicide candidate. Total of 107 biochemical inhibitors reported to inhibit over than 100 different plant enzymes were purchased from commercial chemical companies. 15 inhibitors and 34 enzymes were selected by germination assay, seedling assay, wheat leaf disc assay, and whole plant assay. Among them, seven compounds of purine, phehyl-hydrazine, o-phenanthroline, oleylamine, dicyclohexylcarbodiimide, 7,8-benzoquinoline, and aminooxyacetic acid showed high herbicidal activity in the whole plant assay under greenhouse while 7,8-benzoquinone, 8-hydroxyquinoline, 2,2'-dipyridyl, and o-phenanthroline inhibited seed germination of barnyardgrass, rice, and tomato at concentrations of 1.25 to $5{\mu}M$. The compounds of 7,8-benzoquinoline, chlorpromazine, cyanuric fluoride, 4-methylpyrazole, oleylamine, tranylcypromine, and trifluoperazine inhibited the growth of cyanobacteria at 30 to $100{\mu}M$. The compounds of dicyclohexylcarbodiimide and chlorpromazine exhibited whitening effect on tile wheat leaf disc at $100{\mu}M$. These results suggest that the plant-specific enzyme inhibitors which have biological activities may supply the target enzyme for developing new herbicide candidate.

• Asian Journal of Turfgrass Science
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• v.12 no.4
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• pp.203-210
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• 1998

Environmental concerns arising from synthetic herbicides in plant management systems have led to an interest in plant-derived compounds as natural herbicides. Inhibitory effects of compounds extracted with 50% methanol from corn (Zea mays L.) and pine (Pinus densiflora L.) were evaluated on large crabgrass (Digitaria sanguinalis (L.) Scop.), annual bluegrass Poa annua L.), radish (Raphanus sativus L.), and perennial ryegrass (Lolium perenne L.) The aqueous extracts inhibited seed germination and had postemergence activity on the four species. The stability of biological activity of corn grain, stover, and root extracts was not affected by heating to $135^{\circ}C$ or freezing/thawing treatments when applied at levels above 0.25kg m(sup)-2 based on dry weights of powders before extraction. Heating reduced the activity of pine litter and bark extracts at all levels except the highest application level but had little effect on pine needle extracts.

• Asian Journal of Turfgrass Science
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• v.8 no.3
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• pp.167-177
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• 1994

The relationship between microbial activity and physico-chemical characteristics of golf course soils were investigated in Kyonggi Province with different open years. The increasing tendency of soil PH with depth seemed to the result of mineral leaching. Exchangeable $Ca^2$+ , $Mg^2$+ and K+ showed relatively higher concentration in lower horizon indicating the leaching of minerals. The minerals were heavily leached in older golf course. There was a significant positive correlation between pH and $Ca^2$+.The contents of organic matters, total nitrogen and phosphorus were high in higher horizon.Dehydrogenase activity(DHA) and the content of ATP were determined as an index of soil microbial activity. DHA value was significantly different with golf club as well as golf courses ac-cording todifferent open year. This indicates that DHA was affected by several fertilizertreatments rather than herbicide pesticide treatments. DHA was positively correlated with water holding capacity and total nitrogen. The content of ATP was high in fairway and in golf course with older open year, showing the similar tendency with the results of DHA.

• Korean Journal of Weed Science
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• v.6 no.1
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• pp.67-75
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• 1986

This study was undertaken to investigate the interrelation between herbicide and insecticide and fungicide on rice (Oryza saliva L.) at various growth stages. Carbamate insecticide BPMC (2-sec-butylphenylmethyl-carbamate) severely inhibited germination of rice when applied alone and in combination with herbicides tested. No germination inhibition was obtained with thio- and dithiocarbamate pesticides. Post-germination growth of rice was severely inhibited by the treatments which were combined with BPMC irrespective of herbicides studied. Phytotoxicity of pendimethalin (3,4-dimethyl-2,6-dinitro-N-1-ethyl propylamine) was reduced by antagonistic effect of organophosphorus compounds. When herbicides were applied with either insecticide or fungicide, post-germination growth of rice was more greatly affected by the concentration of herbicides than that of insecticides or fungicides. Most of herbicide-insecticide or herbicide-fungicide treatments did not cause great phytotoxicity on rice when applied 5 days after transplanting. Foliage activity of phenoxy herbicide 2,4-D (2,4-dichlorophenoxy acetic acid) and MCPA [(4-chloro-o-tolyl) oxy acetic acid] increased with addition of carbamate and urea pesticides.

• Korean Journal of Weed Science
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• v.7 no.2
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• pp.200-207
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• 1987

This study was conducted to select and develop herbicide resistant plant through tissue culture. Growth response of seedlings and callis of various rice varieties with Echinochloa species was assessed under the treatment of various rates of butachlor [N-(butoxy methyl)-2-chloro-2', 6'-diethyl acetamide] and simetryne [2,4-bis(ethyl amino)-6-methyl thio-1,3,5-triazine]. Further, succinate dehydrogenase activity was determined in herbicide treated callus to characterize different response of plants to herbicide. Rice variety like Sangpung showed relative resistance in both callus and seedling states against butachlor, indicating maintenance of resistance. However, in the simetryne treatment, the similar response was not observed in callus and seedling state, although there was a great different response among plant materials against simetryne. Rice variety which exhibited resistance in callus and seedling states showed low succinate dehydrogenase inhibition index. Succinate dehydrogenase inhibition index can be used as an important marker characters to differentiate varietal response of plant to herbicide. Rice plant was differentiated from butachlor and simetryne tolerant callus treated at $2.5{\times}10^{-5}$ M is growing under the growth chamber and can be used for resistant source.

• Environmental Analysis Health and Toxicology
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• v.13 no.3_4
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• pp.117-123
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• 1998

Paraquat is a useful nonselective herbicide widely used throughout the world. However, accidental or intentional ingestion of the paraquat cause fetal pulmonary injuring. But there is not suitable antidote of paraquat intoxication and therapeutic agents now be used are not effective. So, in this study we intended to evaluate the inhibitory effects of DDB(dimethyl-4,4'dimethoxy-5,6,5',6'-dimethylene dioxyphenyl-2,2'-dicarboxylate) on paraquat toxicity. DDB (100mg/kg) was administered orally to SD rats lhr after paraquat(50mg/kg) injection. After 24 hours, the biochemical parameters of blood and tissues were examined. In paraquat treated groups sGPT, sGOT, BUN, creatinine, MDA and alkaline phosphatase levels in blood and MDA, glucose-6-phosphatase activity in tissues were elevated by 2 to 5 times of normal values. However in schizandrin treated groups, sGPT, sGOT, MDA and alkaline phosphatase activity in blood and MDA and glucose-6-phosphatase activity were significantly decreased to notmal levels but not in biochemical parameters of nephrotoxicity, BUN and creatinine levels. Therefore, we concluded that schizandrin can be used as an antidote of pulmono, hepatotoxicity of paraquat.

• Proceedings of the Korean Society for Bioinformatics Conference
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• 2003.10a
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• pp.277-287
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• 2003

Acetolactate synthase (ALS, EC 4.1.3.18; also referred to as acetohydroxy acid synthase) catalyzes the first common step in the biosynthesis of valine, leucine, and isoleucine in microorganisms and plants. Recently X-ray structure of yeast ALS was available. Pair-wise alignment of yeast and tobacco ALS sequences revealed 63% sequence similarity. Using Deep View and automatic modeling on Swiss model server, we have generated reliable models of tobacco ALS based on yeast ALS template with a calculated pair-wise RMSD of 0.86 Angstrom. Functional roles of four residues located on the subunit interface (H142, El43, M350, and R376) were examined by site-directed mutagenesis. Seven mutants were generated and purified, of which three mutants (H142T, M350V, and R376F) were found to be inactivated under various assay conditions. The H142k mutant showed moderately altered kinetic properties. The E143A mutant increased 10-fold in K$_m$ value while other parameters remained unchanged. The M350C mutant was strongly resistant to three tested herbicides, while the R376k mutant can bind with herbicide carder at similar affinity to that of wild type enzyme, as determined by tryptophan quenching study. Except M350V mutant, all other mutants were ate to bind with cofactor FAD. Taken together, it is likely that residues H142 and E143 are located at the active site, while residues M350 and R376 are possibly located at the overlapping region of active site and herbicide binding site of the enzyme. Our data also allows us to hypothesize that the interaction between side chains of residues M350 and R376 are probably essential for the correct conformation of the active site. It remains to be elucidated that, whether the herbicide, upon binding with enzyme, inactivates the enzyme by causing change in the active site allosterically, which is unfavorable for catalytic activity.

• Journal of Life Science
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• v.14 no.2
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• pp.368-373
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• 2004

We have obtained fertile transgenic rice plants resistant to the broad spectrum herbicide Bast $a^{(R)}$ (active ingredient phosphinothricin, PPT) by PEG-mediated transformation procedure. The plasmid pCaMV35S::Bar was used to deliver the bar gene into embryogenic suspension culture-derived protoplasts of rice (Oryza sativa L.). Transformed plants were regenerated and selected on medium containing 15 mg/l of phosphinothricin. Stable integration and expression of the bar gene in transgenic rice plants was confirmed by Southern and Northern blot analysis. Transgenic $R_1$ plants were also confirmed by assays for phosphinothricin acetyltransferase (PAT) activity. The bar gene was expressed in the primary transgenic rice plants and in the next generation progeny, in which it showed a 3 : 1 Mendelian inheritance pattern. Transgenic $R_1$ and $R_2$ plants were resistant to the herbicide Bast $a^{(R)}$ when sprayed at rates used in field practice.ice.