• The Korean Journal of Physiology and Pharmacology
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• 제12권1호
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• pp.7-12
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• 2008

OLETF (Otsuka Long-Evans Tokushima Fatty) rats are characterized by obesity-related insulin resistance, which is a phenotype of type 2 diabetes. Sulfonylurea drugs or benzoic acid derivatives as inhibitors of the ATP-sensitive potassium $(K_{ATP})$ channel are commercially available to treat diabetes. The present study compared sulfonylurea drugs (glimepiride and gliclazide) with one of benzoic acid derivatives (repaglinide) in regard to their long-term effect on ameliorating insulin sensitivity in OLETF rats. Each drug was dissolved and fed with drinking water from 29 weeks of age. On high glucose loading at 45 weeks of age, response of blood glucose recovery was the greatest in the group treated with glimepiride. On immunohistochemistry analysis for the Kir6.2 subunit of $K_{ATP}$ channels, insulin receptor ${\beta}$-subunits, and glucose transporters (GLUT) type 2 and 4 in liver, fat and skeletal muscle tissues, the sulfonylurea drugs (glimepiride and gliclazide) were more effective than repaglinide in recovery from their decreased expressions in OLETF rats. From these results, it seems to be plausible that $K_{ATP}$-channel inhibitors containing sulfonylurea moiety may be much more effective in reducing insulin resistance than those with benzoic acid moiety. In contrast to gliclazide, non-tissue selectivity of glimepiride on $K_{ATP}$ channel inhibition may further strengthen an amelioration of insulin sensitivity unless considering other side effects.

• 한국작물학회지
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• 제47권4호
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• pp.328-334
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• 2002

A Lindernia dubia (L.) Pennell var. dubia accession from Jeonnam province, Korea was tested for resistance to sulfonylurea (SU) herbicides, imazosulfuron and pyrazosulfuron-ethyl in whole-plant response bioassay. The accession was confirmed resistant to both herbicides. The $GR_{50}$ (herbicide concentration that reduced shoot dry weight by 50%) values of resistant accession were 264 and 19 times higher to imazosulfuron and pyrazosulfuronethyl, respectively, than that of the standard susceptible accession. The surviving resistant L. dubia after pyrazosulfuron-ethyl + molinate application can be controlled by sequential applications of soil-applied herbicides, butachlor, dithiopyr, pyrazolate, and thiobencarb and foliar herbicides, bentazon. Sulfonylurea-based mixtures such as mixtures of azimsulfuron + anilofos, bensulfuron-methyl + oxadiazon, pyrazosulfuron-ethyl + fentrazamide, and pyrazosulfuron-ethyl + anilofos + carfentrazon can also be used to control the surviving resistant L. dubia. However, use of these mixtures should be restricted to a special need basis. Thus, we suggest that sequential applications of non-SU-based mixtures such as butachlor + pyrazolate and MCPB + molinate + simetryne be used to control the surviving resistant L. dubia after SU herbicide applications. Rice yield was reduced 24 % by resistant L. dubia that survived after the pyrazosulfuron-ethyl + molinate application compared with pyrazolate + butachlor in transplanted rice culture. In vitro ALS activity of the resistant biotype was 40 and 30 times more resistant to imazosulfuron and pyrazosulfuron-ethyl, respectively, than the susceptible biotype. Result of in vitro ALS assay that the resistance mechanism of L. dubia to SU herbicides may be due, in part, to an alteration in the target enzyme, ALS.

• The Plant Pathology Journal
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• 제21권1호
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• pp.77-82
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• 2005

A summer annual weed of monochoria (Monochoria vaginalis) grows in the edges of rice paddies, ditches, and moist upland throughout Korea. It is very difficult to control with herbicide because of its sulfonylurea resistance. It is very competitive with fast growing pattern, that can cause reducing yields of rice. Brown leaf blight of monochoria (Monochoria vaginalis) occurred naturally in rice paddy, is first reported in Korea. The fungal isolate BWC01-54 was successfully isolated from the diseased leaves of monochoria. The fungus BWC 01-54 was grown well at $25-28^{\circ}C$, conidia of the greysh black brown mycelia were abundant produced on PDA at 15 days. The fungus was grown well in potato dextrose broth at $28^{\circ}C$ and fully grown within 10 days in 250 ml of flask. In host and pathogenicity test, conidia suspension of BWC01-54 was the most effective to control of monochoria compare to others isolates. Typical symptoms having pin point brown lesions were formed on stem and leaf and which severely affected the whole plants ware blighted within two weeks, respectively. Under paddies field condition, conidial suspension of the fungus BWC01-54 gave around 90% control. Therefore, we conclude that the fungus may have a potential as a biological control agent against sulfonylurea resistance weed in rice paddy.

• 농약과학회지
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• 제13권4호
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• pp.290-297
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• 2009

본 연구는 한국에서 발생하고 있는 설포닐우레아계 제초제 저항성 및 감수성 물달개비의 ALS 염기서열 분석에 의한 ALS 유전자의 특성과 제초제 저항성 메카니즘을 구명하기 위하여 실시하였다. 감수성 및 저항성 두 계통의 biotype에서 815개의 염기서열을 분석하였다. 분석된 염기서열에서 감수성 biotype으로부터 4개 clone, 저항성 계통으로부터 15개 clone, 총 19개의 clone들을 크게 4 group으로 분류할 수 있었다. 첫 번째 group은 저항성 및 감수성 biotype의 ALS 유전자 염기서열이 차이가 없었으며, 두 번째 그룹은 아미노산 197번째의 proline이 DNA의 점돌연변이(point mutation)에 의해 serine으로 변화된 부분이다. 세 번째 group은 6곳에서 점돌연변이에 의한 아미노산치환이 발생하였으며, 네 번째 group는 첫 번째 group과 세 번째 group 중간적 특성으로 3곳에서 염기서열 점돌연변이에 의해 아미노산 치환이 있었다. 따라서 하나의 물달개비 식물체에서 여러 가지 형태의 ALS 유전자가 존재할 수 있으며, 물달개비 저항성 biotype의 ALS 유전자는 Domain A 부분에 있는 아미노산 197번째 proline이 염기서열 변화에 의해 serine으로 돌연변이 되었다.

• 농약과학회지
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• 제8권1호
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• pp.63-70
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• 2004

Sulfonylurea(SU)계 제초제에 대한 저항성 물옥잠이 최근 한국에서 발생되고 있는데, 저항성 물옥잠 을 시기적절하게 효과적으로 방제하기 위해서는 신속 정확하고 실용적인 조기진단법 개발이 매우 중요하다. 지금까지 제초제 저항성 검증은 종자를 파종하여 어린식물에 제초제를 살포하는 방법을 사용하였으나 이러한 방법은 많은 시간이 소요될 뿐만 아니라 비실용적이다. 그러나 본 연구는 지표로부터 $1\sim2cm$에서 식물체를 절단한 다음 제초제를 처리하여 식물체의 생존율과 재생된 초장에 의하여 저항성을 검증하는 신속 정확한 새로운 방법이다. 이 새로운 조기진단법에 의하여 SU계 제초제 저항성 물옥잠은 적어도 7일 이내 저항성 검증이 가능하였다. 제초제 저항성이 진단되면 잡초를 효과적으로 방제하기 위해서는 식물 생육 단계에 맞는 제초제를 선발하는 것이 매우 중요하다. SU계 혼합 제초제 처리 후 생존한 저항성 물옥잠은 butachlor+pyrazolate 입제나 bentazone 액제와 2,4-D 액제를 혼용하여 처리하는 것이 효과적이었다.

• 농약과학회지
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• 제11권4호
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• pp.269-275
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• 2007

4개의 서로 지역 계통별 sulfonylurea(SU)계 제초제 저항성 물달개비의 저항성 정도 차이를 구명하기 위하여 SU계 제초제들에 대한 식물체 및 acetolactate synthase(ALS) 반응 차이를 감수성 계통과 비교 분석하였다. 나주, 논산, 김제 지역에서 채집된 저항성 물달개비들은 SU계 제초제들의 기준량에서 거의 영향을 받지 않았다. 사용된 SU계 제초제들의 기준량에 대한 나주, 논산, 김제 지역계통의 건물 중 50% 억제 제초제 농도인 $GR_{50}$은 감수성계통(청도) 보다 각각 $8{\sim}33$배, $8{\sim}30$배, $7{\sim}32$배 높게 나타났다. 그러나 김해 채집계통의 $GR_{50}$은 감수성 채집계통에 비해 $4{\sim}13$배 높게 나타나 중간정도의 저항성을 보였다. 나주, 논산, 김제에 대한 ALS 50% 억제 제초제 농도인 $I_{50}$은 감수성 채집계통에 비해 각각 $25{\sim}66$배, $9{\sim}26$배, $10{\sim}24$배 높게 나타났다. 그러나 김해 채집계통의 91%은 감수성 채집계통에 비해 $4{\sim}9$배 높게 나타났다.

• BMB Reports
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• 제31권3호
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• pp.287-295
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• 1998

Acetolactate synthase (ALS) is the first common enzyme in the biosynthesis of L-Ieucine, L-isoleucine, and L-valine. The sulfonylurea-resistant ALS gene from Nicotiana tabacum was cloned into the bacterial expression vector pGEX-2T. The resulting recombinant plasmid pGEX-ALS3 was used to transform Escherichia coli strain XL1-Blue, and the mutant tobacco ALS (mALS) was expressed in the bacteria as a protein fused with glutathione S-transferase (GST). The fusion product GST-mALS was purified in a single step on a glutathione-Sepharose column. ALS activities of 0.9-2.5 ${\mu}mol/min/mg$ protein were observed in the GST-mALS, and the Km values for pyruvate, FAD, and TPP were 10.8-24.1, $(1.9-8.9){\times}10^{-3}$, and 0.14-0.38 mM, respectively. The purified GST-mALS was resistant to both the sulfonylurea and the triazolopyrimidine herbicides, and lost its sensitivity to end products, L-valine and L-leucine. For comparision, the tobacco wild-type recombinant ALS fused with GST, GST-wALS, was also characterized with respect to its pyruvate and cofactor bindings. These results suggest that the purified mutant recombinant tobacco ALS was functionally active, that the mutations resulting in herbicide resistance has affected pyruvate and cofactor bindings," and that the two classes of herbicides interact at a common site on the plant ALS.

• Weed & Turfgrass Science
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• 제6권1호
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• pp.28-31
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• 2017

The mutation rate of proline in the position 197 (Pro197) in acetohydroxy acid synthase (AHAS) is highest among sulfonylurea (SU) herbicide-resistance mutants. Therefore, it is significant to investigate the resistance mechanism for the mutation and to develop the herbicides specific to the mutants. SU herbicide resistance mechanism of the mutants, 197Ser, 197Thr and 197Ala, in AHAS were targeted for designing new SU-herbicide. We did molecular dynamics (MD) simulation for understanding SU herbicide-resistance mechanisms of AHAS mutants and designed new herbicides with docking and MD evaluations. We have found that mutation to 197Ala and 197Ser enlarged the entrance of the active site, while 197Thr contracted. Map of the root mean square derivation (RMSD) and radius gyrations (Rg) revealed the domain indicating the conformations for herbicide resistant. Based on the enlarging-contracting mechanism of active site entrance, we designed new herbicides with substitution at the heterocyclic moiety of a SU herbicide for the complementary binding to the changed active site entrances of mutants, and designed new herbicides. We confirmed that our screened new herbicides bonded to both AHAS wild type and mutants with higher affinity, showing more stable binding conformation than the existing herbicides.

• 한국작물학회지
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• 제48권4호
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• pp.286-291
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• 2003

Monochoria vaginalis is one of the most troublesome resistant weeds in Korean rice culture. Thus, the objectives of this study were to evaluate the response of M. vaginalis resistant to sulfonylurea(SU) herbicides and to determine alternative herbicides for the control of resistant M. vaginalis in direct seeded and transplanted rice culture in Korea. In greenhouse studies, the resistant biotype was 31-, 38-, 3172-, and 7-fold more resistant to ben-sulfuron-methyl, cyclosulfamuron, imazosulfuron, and pyrazosulfuron-ethyl, respectively, than the susceptible biotype, indicating cross-resistance to the SU herbicides used in this study. Non-SU herbicides, butachlor, carfentrazone-ethyl, mefenacet, pretilachlor, pyrazolate, and thiobencarb, several SU herbicide-based mixtures, ethoxysulfuron plus fentrazamide, pyrazosulfuron-ethyl plus pyrazolate plus simetryn, and non-SU herbicide-based mixtures, pyrazolate plus butachlor, pyrazolate plus pretilachlor, simetryn plus molinate, carfentrazone-ethyl plus butachlor, and carfentrazone-ethyl plus thiobencarb can be used to control both the resistant and susceptible biotypes of M. vaginalis when applied before the second leaf stage. In the field experiment, the resistant biotype of M. vaginalis that survived from the paddy fields treated with a SU herbicide-based mixture could effectively be controlled by using mixtures of bentazone plus MCPA, bentazone plus mecoprop-P, and bentazone plus 2,4-D when applied at 2 or 4 main leaves. Our results suggest that the SU-resistant M. vaginalis had not developed multiple resistances to herbicides with different modes of action. In particular, bentazone plus MCPA and bentazone plus mecoprop-P were effective control measures after failure to control resistant M. vaginalis in Korean rice culture.

• Weed & Turfgrass Science
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• 제2권2호
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• pp.131-137
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• 2013

본 연구는 경상북도 지역의 논에 발생하는 잡초종의 발생과 분포 및 sulfonylurea계 제초제 저항성잡초 발생비율을 조사한 것으로 생활사별 논잡초 분포는 일년생이 91.8%로서 다년생 8.2%보다 많았으며, 형태적 분포는 광엽잡초 85.7%, 사초과 9.1%, 화본과 3.8%였다. 잡초종은 물달개비, 미국외풀, 피, 여뀌바늘, 올챙이고랭이, 미국가막사리이었고, 물달개비가 우점하는 지역과 발생률은 포항, 의성, 상주, 경주 순으로 각각 85.1%, 76.3%, 73.5%, 58.9%였으며, 미국외풀은 영덕, 고령, 군위, 영양, 안동, 예천, 구미, 영천 순으로 발생률은 각각 96.3%, 93.8%, 92.7%, 90.7%, 86.8%, 70.6%, 66.7%, 56.2%로 나타났다. 지역별로 주요 논잡초는 물달개비, 미국외풀, 너도방동사니, 피, 올챙이고랭이 순이었고, 우점도를 1981년, 1992년 및 2012년도와 비교하면 미국외풀(42.8%), 물달개비(37.5%), 너도방동사니(7.9%)순이었다. 논에 발생한 sulfonylurea계 제초제 저항성 잡초는 물달개비, 여뀌바늘, 미국외풀, 올챙이고랭이로 총 4종이었고, 제초제 저항성잡초 가운데 가장 많은 발생면적을 보인 초종은 미국외풀로 11.1%를 차지하였다. 2012년 조사된 지역에 대한 제초제 저항성 잡초 발생률은 15.9%정도로 경북지역의 벼 재배면적(141,005ha)을 고려하면 제초제 저항성잡초 발생면적은 22,420ha정도로 추정되었다.