• Bulletin of the Korean Chemical Society
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• v.34 no.10
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• pp.2909-2914
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• 2013

p-Hydroxyphenylpyruvate dioxygenase (HPPD) is a potent herbicide target that is in current use. In this study, we developed a predictive pharmacophore model that uses known HPPD inhibitors based on a theoretically constructed HPPD homology model. The pharmacophore model derived from the three-dimensional (3D) structure of a target protein provides helpful information for analyzing protein-ligand interactions, leading to further improvement of the ligand binding affinity.

• Bulletin of the Korean Chemical Society
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• v.19 no.2
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• pp.170-174
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• 1998

Migration properties of antidegradants to the surface in NR vulcanizates containing carbon black of 30, 50, and 70 phr were studied using the migration-generating equipment with a vacuum technique. The migration was carried out at 60, 80, and 100 ℃ for 20 h. BHT, IPPD, HPPD, and wax were used as migrants. IPPD migrates faster than the other migrants. Amounts of BHT, IPPD, and HPPD that migrated at 60 and 80 ℃ decrease as the content of carbon black in the vulcanizate increases. Migrations of antidegradants in the NR vulcanizate containing carbon black of 50 phr are faster than those containing carbon black of 30 and 70 phr at 100 ℃. Although n-C23H48 is heavier than HPPD, it migrates faster than HPPD and even faster than BHT at 100 ℃. Influencing factors of carbon black on the migrations are its porous structure and polar functional groups on the surface.

• Weed & Turfgrass Science
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• v.5 no.4
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• pp.187-190
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• 2016

This study was conducted to determine phytotoxicity of domestic rice varieties and characteristic of sensitive gene involved in herbicide reaction of 4-HPPD (4-hydroxy phenylpyruvate dioxygenase) inhibiting herbicides. The five rice varieties were grown for 2 to 3 leaf stage on seedling trays and then transplanted into plastic pot: 4-Japonica type (Sangjubyeo, Sambaekbyeo, Sanduljinmi and Kumyoung) varieties and 1-Indica type variety (IR8). We trialled standard (14 g a.i. $10a^{-1}$) and double fold (28 g a.i. $10a^{-1}$) dose of benzobicyclon treatment at 10 days after transplanting in order to investigate phytoxicity. The Japonica-type Sangjubyeo showed no rice injury but Indica-type IR8 show 4-5 (standard) and 5-6 (double fold) phytoxicity levels. In spite of Japonica-type, Sanduljinmi and kumyoung showed 3-4 and 4-5 levels. Target resistant gene, Hydroxyphenylpyruvate dioxygenase inhibitor sensitive gene No.1 (HIS1) have been isolated from five domestic rice cultivars (Sangjubyeo, Sambaekbyeo, Sanduljinmi, Kumyoung and IR8). Results of the sequence through PCR, all five tested rice cultivars had HIS1 gene regardless to rice cultivars. And the difference between rice varieties from sequence of HIS1 were identified some variation in genes.

• Elastomers and Composites
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• v.34 no.2
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• pp.147-155
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• 1999

Waxes compounded into rubber migrate to the surface and form a protection film on the rubber surface. In general, antiozonants were used with wax to protect ozonation of rubber. Influence of wax barrier formed on the surface of a rubber vulcanizate on migration of antiozonants was studied using natural rubber (NR) vulcanizates containing various type waxes. IPPD (N-isopropyl-N'-phenyl-p-phenylenediamine), HPPD (N-l,3-dimethylbutyl-N'-phenyl-p-phenylenediamine), SBPPD (N,N'-di(sec-butyl)-p-phenylenediamine), and DMPPD (N,N'-di(1,4-dimethylpentyl)-p-phenylenediamine) were employed as antiozonants. Migration experiments were performed at constant temperatures of 60 and $80^{\circ}C$ for 10, 20, 30 days using a convection oven. The migration rates of the antiozonants in the vulcanizate without wax are faster than those in the vulcanizates containing waxes. The antiozonants migrate slower in the vulcanizate containing wax with a high molecular weight distribution than in the vulcanizate with a low one. The migration rates of DMPPD and SBPPD are faster than those of HPPD and IPPD.

• Korean Journal of Weed Science
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• v.32 no.3
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• pp.240-255
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• 2012

The objectives of this study were to investigate the levels of phytotoxicity of rice varieties to HPPD (4-hydroxy phenylpyruvate dioxygenase)-inhibiting herbicides known for their efficiency to control the sulfonylureas-resistant weed species：mestrione, benzobicyclone, and tefuryltrione. The twenty-six rice varieties (8-Japonica ${\times}$ Indica-type varieties and 18-Japonica-type varieties) were grown for 25 days on seedling trays and then transplanted to paddy rice fields followed by herbicide treatment i.e. standard and double doses of there respective herbicides at 5, 10, and 15 days after transplanting. Although mestrione, benzobicyclone and tefuryltrione are all HPPD-inhibiting herbicides, the phytotoxicity symptoms of the different rice varieties based on the timing of application and doses of the herbicides were significantly different. The Japonica ${\times}$ Indica-type varieties showed much more phytotoxicity symptoms than Japonica-type varieties in all applied herbicides. Increasing herbicidal doses of mesotrione, and an earlier application of and increasing herbicidal doses of benzobicyclon caused severe phytotoxicity symptoms. On the other hand, phytotoxicity due to tefuryltrione did not exhibit significant differences between rice varieties in either the timing of application or dose of the herbicide. Regardless of timing of application and dose of the herbicides, Hangangchalbyeo-1, Hyangmibyeo-1 and high-yield rice varieties such as Namcheonbyeo, Dasanbyeo, Areumbyeo, and Hanareumbyeo, which belong to the Japonica ${\times}$ Indica-type varieties, showed 5 to 8 levels of phytotoxicity symptoms including albinism, browning, detached leaf, and necrosis to mesotrione and benzobicyclon whereas only 1 to 3 levels of phytotoxicity symptoms (chlorosis, albinism, and browning) were seen with to tefuryltrione application. The Japonica-type varieties exhibited only slight phytotoxicity symptoms (1~2 levels) in conformity with the timing of application and doses of the herbicides. However, there were significant differences among the Japonica-type rice varieties, depending on the type of herbicide. Thirteen-Japonica type rice varieties were sensitive to benzobicyclone while 4-Japonica-type and 7-Japonica-type varieties showed phytotoxicity symptoms such as chlorosis and albinism with mestrione and tefuryltrione application, respectively. Therefore, we suggest that the combined-type herbicides including mestrione, benzobicyclone and tefuryltrione should be rejected in paddy fields where rice is grown for either human consumption (functional or processed rice) or livestock feed because of severe phytotoxicity symptoms on the various rice varieties seen regardless of the timing of application and doses of the herbicides.

• Korean Journal of Weed Science
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• v.31 no.2
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• pp.192-198
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• 2011

This study was conducted to investigate the herbicidal activity against Scirpus planiculmis (SCPPL) which has been reported as resistant biotype on sulfonylurea (SU) herbicides at the west coast reclaimed area first and proliferated continuously at Hwasung and Pyeongtaek in Gyeonggi province, and some Chungnam province. In order to investigate resistance breakability against SCPPL, new rice herbicides containing tefuryltrione [p-hydrophenyl pyruvate dioxygenase (HPPD) inhibitor], pyrimisulfan and triafamone[actolactate synthethase (ALS) inhibitor] were tested. In both lab and field experiments, tefuryltrione GR, 4-HPPD inhibitor showed growth retardation with a bleaching on the young leaves of SCPPL at early time after treatment. However, it restored and regerminated with insufficient control effect. On the other hand, pyrimisulfan+mefenacet SC, triafamone+tefuryltrione GR, and ALS inhibitor showed excellent control effect on SU-resistant SCPPL with growth retardation and necrosis. In particular, pyrimisulfan+mefenacet SC showed excellent controlling effect on SU-resistant SCPPL in regional field experiments.

• 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.

• Weed & Turfgrass Science
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• v.5 no.4
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• pp.191-195
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• 2016

Tefuryltrione is a new hydroxyphenylpyruvate dioxygenase (HPPD) inhibitor, which has been recently registered for the use for paddy rice, Korea. Dose-response studies were conducted to compare rice safety and weed control efficacy of tefuryltrione against Eleocharis kuroguwai. When rice and E. kuroguwai were applied at a range of doses of tefuryltrione, $GR_{90}$ values (the dose required to inhibit weed growth by 90%) of E. kuroguwai were $82.38-93.39g\;a.i.\;ha^{-1}$ in two independent experiments. The $GR_{10}$ values (the dose required to inhibit rice growth by 10%) of tefuryltrione for rice were $297.77-471.54g\;a.i.\;ha^{-1}$. As a result, the selectivity indices ($GR_{10}$ for $rice/GR_{90}$ for E. kuroguwai) of tefuryltrione were 3.19-5.72. Therefore, these results demonstrate that tefuryltrione has a relatively high selectivity between rice and E. kuroguwai with a high herbicidal activity against E. kuroguwai and a good rice safety.

• Applied Biological Chemistry
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• v.48 no.4
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• pp.345-351
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• 2005

To access the natural products of uncultured microorganisms, we constructed and screened the metagenomic DNA libraries by using a cosmid vector and DNA inserts isolated directly from soil. Initial screening of the libraries in Escherichia coli resulted in the isolation of several clones that produce a dark brown color when grown in LB medium. One of the positive clones, designed pYS85C, was transposon mutagenized and the DNA surrounding the transposon insertions in cosmids that no longer conferred the production of brown pigment to E. coli was sequenced. Annotation of the pYS85C sequence obtained from the transposon mutagenesis experiment indicated a single 393 amino acid open reading frame (ORF) with a molecular mass of about 44.5 kDa, predicted to be a 4-hydroxyphenylpyruvate dioxygenases (HPPDs), was responsible for the observed brown pigment. In a BLAST search against deposited sequence, the translated protein from this ORF showed moderate-level identity (>60%) to the other known HPPDs and was most conserved in the C-terminal region of the protein. These results show that genes involved in natural product synthesis can be cloned directly from soil DNA and expressed in a heterologous host, supporting the idea that this technology has the potential to provide novel natural products from the wealth of environmental microbial diversity and is a potentially important new tool for drug discovery.

• Elastomers and Composites
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• v.35 no.1
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• pp.38-45
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• 2000

Influence of rubber composition on migration of antiozonants to the surface in ternary rubber-based vulcanizates composed of natural rubber (NR) styrene-butadiene rubber (SBR), and butadiene rubber (BR) was studied. Of the three rubbers, contents of two rudders were same and only the other one content was different (variable rubber) IPPD and HPPD were employed as antiozonants. Migration experiments were performed at $60^{\circ}C$ for 21 days and outdoors for 4 months. Migration rates of the antiozonants increase by increasing the content ratio of the variable rubber in the vulcanizares from NR/SBR/BR=1/1/0.2 to 1/1/1 and then decrease with an increase of the content ratio of the variable rudder from 1/1/1 to 1/1/5. Migration behaviors of the antiozonants in the ternary rudder-based vulcanizates depending on the rubber composition were explained by the intermolecular interactions between rubber and antiozonant, by the solubility difference of the antiozonants for the rubbers, and by the interface formed between dissimilar rubbers in the triblends.