• 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.

• 대한임상독성학회지
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• 제17권2호
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• pp.126-131
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• 2019

Purpose: Herbicide-related mortality has decreased since the complete ban of paraquat product sales in 2012, but there still have been other herbicides intoxications with relatively severe complications. Glyphosate and glufosinate herbicides are used widely, and considerable research has been conducted. Chlorophenoxy herbicide is another major herbicide that has shown poor outcomes and mortality without proper management, but research in this area is lacking. Therefore, this study compared the clinical features of chlorophenoxy herbicide with those of other herbicides. Methods: The medical records of patients exposed to herbicides at a tertiary academic university hospital in Korea from May 2014 to April 2019 were reviewed retrospectively. The demographic and clinical data of 135 patients were then analyzed to identify the recent herbicides intoxication trends after the paraquat sales ban, focusing mainly on chlorophenoxy herbicide poisoning. Results: Of the 135 patients, 13 patients (9.6%) had chlorophenoxy herbicide poisoning. No significant differences in all the variables were observed between the chlorophenoxy herbicide poisoning group and non-chlorophenoxy herbicides poisoning groups. Toxic symptoms after poisoning varied from nothing noticeable to confusion; none of the patients had severe complications after their treatments. Conclusion: Acute chlorophenoxy poisoning is relatively less severe, with lower mortality rates than glyphosate and glufosinate poisoning.

• 한국잡초학회지
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• 제15권1호
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• pp.46-53
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• 1995

Thiocarbamate계(系) 제초제(除草劑) 4종(種)(molinate, dimepiperate, esprocarb 및 thiobencarb)의 살초력(殺草力)과 세포분열(細胞分裂) 및 신장(伸長)에 미치는 영향을 비교 검토하였다. 실험(實驗) 제초제(除草劑) 4종(種) 모두 $10^{-6}-10^{-4}M$ 처리수준(處理水準)에서 벼와 피의 발아(發芽) 및 발아후(發芽後) 뿌리 생장(生長)에는 영향을 미치지 않고, 발아후(發芽後) 지상부(地上部) 생육(生育)에만 영향을 미쳤다. 또한 gibberellin-유기(誘起) ${\alpha}$-amylase 생합성(生合成)에 대해서는 실험(實驗) 제초제(除草劑) 모두 $10^{-5}M$ 처리수준(處理水準)에서는 영향이 없었지만, $10^{-4}M$에서는 무처리(無處理) 대비(對比) 약 50-60%의 저해를 나타내었다. 피 파종 후 7 일에 처리된 thiocarbamate계(系) 제초제(除草劑)의 초장(草長) 생육 50% 억제에 요구되는 약량(藥量)은 molinate 146g, dimepiperate 91g, esprocarb 96g 및 thiobencarb 102g ai/10a이었다. 4종(種)의 thiocarbamate계(系) 제초제(除草劑)는 $10^{-4}M$ 처리(處理) 농도(濃度)에서 세포분열(細胞分裂)에 영향을 미치지 않았고, $10^{-3}M$ 농도(濃度)에서 약 31-47%의 저해(沮害)를 보였다. 세포신장(細胞伸長)에는 $10^{-5}M$ 처리수준(處理水準)에서 약 33-38%의 억제를 보였다. 실험(實驗) thiocarbamate계(系) 제초제(除草劑) 모두 IAA-유기(誘起) 엽초 신장을 저해하였다.

• ALGAE
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• 제22권4호
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• pp.319-323
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• 2007

This study was conducted with using chlorophyll a fluorescence (indicated as photosynthetic activity) to examine the toxic effect of 96 h exposure of heavy metals and herbicides on the benthic diatom Nitzschia sp. which was isolated from pristine sediment in Pamquat Harbour, Nova Scotia, Canada. Samples of benthic diatom were exposed to 0, 0.01, 0.1 and 1 mg L–1 of copper, 0, 1, 10 and 100 mg L–1 of chrome (VI), 0, 2.45, 24.5 and 245 mg L–1 of paraquat dichloride, and 0, 4.37, 43.7 and 437 mg L–1 of alachlor during 96 hours. The effective quantum yield of photochemistry (ΔF/Fm’) was evaluated by subjecting light acclimated samples to saturating pulses of light using a pulse amplitude modulated (PAM) fluorometer. The impact of heavy metals on Nitzschia sp. photosynthesis was not severe in < 1 mg L–1 but in the high concentrations (> 1 mg L–1) clearly increased toxic stress during 96 h. Herbicides had a limited impact during the exposure period but clearly increased stress on the benthic diatom with increasing concentrations. Acute response of Nitzschia sp. to selected heavy metals and herbicides was characterized, and the capacity of a benthic diatom to tolerate and recover from toxic stress was assessed.

• Weed & Turfgrass Science
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• 제7권1호
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• pp.72-75
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• 2018

Balloon flower (Platycodon grandiflorum) is one of minor crops in Korea. Only four ACCase inhibiting herbicides are registered for P. grandiflorum and the farmers usually use general but unregistered herbicides which can cause critical phytotoxicity. So, this study was conducted to investigate effects of alachlor and pendimethalin on germination and early growth of P. grandiflorum. To evaluate the effect of alachlor and pendimethalin, two herbicides were treated to the seeds in petri-dish and soil. In the petri-dish, alachlor completely inhibited the germination as well as pendimethalin inhibited the germination slightly but not significantly. In case of soil application, alachlor inhibited germination and plant height of P. grandiflorum significantly as well as pendimethalin inhibited plant height and root length significantly. We showed the possibility of phytotoxicity of alachlor and pendimethalin to P. grandiflorum and strongly suggest that two herbicides should not be used to the cultivation of P. grandiflorum. Unregistered herbicides should not be used for weed management and additional researches for screening of safe herbicide to minor crops should be conducted as soon as possible.

• 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.

• 농약과학회지
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• 제2권1호
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• pp.1-11
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• 1998

The generally accepted idea for carbohydrate translocation in plants is an osmotic pressure flow hypothesis. According to the hypothesis, a high concentration of carbohydrate in the phloem of carbohydrate synthesis regions (source) causes a water influx into the phloem. The generated osmotic potential in the phloem is responsible for long distance carbohydrate transport through the positive hydrostatic pressure. In regions of carbohydrate utilization and storage (sink), translocated carbohydrates are continuously metabolized and compartmentalized, generating a concentration gradient between source and sinks. In this system, carbohydrates load into the phloem (phloem loading) and unload out of the phloem (phloem unloading). Phloem-mobile herbicides that are applied to plants are also translocated from the source to sinks. However, some experimental results reveal that the patterns of phloem translocation between carbohydrates and herbicides are different. The differences are due, in part, to the physico-chemical properties of herbicides and to the absence/presence of specific carrier(s) in the phloem.

• Applied Biological Chemistry
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• 제21권3호
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• pp.185-192
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• 1978

제초제((除草劑)중 국내에서 많이 사용되는 nitrofen(NIP, TOK), butachlor (Machete) 및 alachlo (Lasso의 잔류성(殘留性)을 조사하기 위하여 가수분해를 거치지 않고 전자(電子)포획검출기가 부설된 깨스크로마토그래피로 분석하는 방법을 확립시킨 후 이들 제초제를 유지(油脂)작물인 유채(油菜), 대두(大豆) 및 수도(水稻)의 재배포장에 사용(施用)하였을 때의 잔류량(殘留量)을 분석하였다. 그 결과 세가지 제초제(除草劑)는 사용후 2주일만에 급격히 감소하였으며 그 이후에는 점차적으로 감소하여 10%수준에 도달하였다. 그러나 유지(油脂)원료인 세 작물의 종자(種子)에는 분석한계치(分析限界値)안에서 전혀 검출(檢出)되지 아니하였다.

• 아시안잔디학회지
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• 제7권2_3호
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• pp.81-94
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• 1993

This study was conducted to investigate the influence of herbicides, simazine, pendimethalin, propyzamide and asulam on the growth of Zoysia matrella when they are treated at different growth stages of the plant. The reaction of Zoysia matrella to herbicides differed depending on kinds of herbicides, their concentcations, and time of treatment. Simazine at the higher concentration of 600g /l0a exhibited inhibitory effect on leaf dry matter and growth of runner when treated on April 5, 1991. The highest inhibition of leaf and runner was observed in the plot applied on May 23, 1990. The sprouting and growth of Zoysia matrella was not affected by all the concentrations of the herbicides applied on October 23,1991. Pendimethalin did not influence the growth of Zoysia matrella at he treatment of April 5. However, at the treatment of May 23, the number and growth of runner was inhibited although the plant height and leaf dry matter was not affected. When pendimethalin was treated on October 23, the growth of runner was very slightly reduced in the next year. In case of propyzamide, there was no inhibitory effect on the growth of Zoysia matrella regardless of treatment of times, methods, and dosages. Greater inhibition in the growth of Zoysia matrella was observed at higher dosage(1,ll0g /l0a)-treated plot on April 5 and all the concentrations treated on May 23. But, no inhibition was observed on the October 23 treatment.

• 한국잡초학회지
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• 제8권2호
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• pp.124-132
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• 1988

Herbicides show many kinds of mode of action and are metabolized in many ways. These biochemical patterns are closely related to the efficacy or mammalian toxicity and also to the selectivity of environmental persistance of herbicides, respectively. In this short review, oxygenase will be discussed as to the metabolisms of monuron, EPTC and bensulfuron methyl, and active oxygens will be reviewed from the standpoint of the mode of action of paraquat and diphenylether herbicides.