• Korean Journal of Environmental Agriculture
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• v.8 no.1
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• pp.7-16
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• 1989

Application of steam distillation on the analysis of pesticide residue in soil, water and crops was studied using the nitrogen distillation apparatus. Most pesticides which were extracted by organic solvents could be analyzed by the steam distillation method. For instance, distillations of PCNB, ${\gamma}-BHC$, ${\alpha}-or$ ${\beta}-endosulfan$, IBP, diazinon, fenthion, fenitrothion, alachlor, butachlor, pretilachlor, metolachlor, pendimethalin, benthiocarb and molinate were possible, but not simazine, atrazine and nitrofen. The optimum volume of distillate for a sufficient extraction of pesticide varied according to kind of pesticide. In general, the volume needed was little for carbamate, but much more for organochlorine. When the definite amount of distillate was obtained and then the condenser was washed by acetone, the optimum volume of distillate was less. Using the steam distillation method, the amount of organic solvent needed for one extraction of pesticide from soil, water and vegetable was less than the conventional solvent extraction method, and the analytical procedure became simpler. The process of concentration and clean up was mostly unnecessary, although a ghost peak was apparent in the gas chromatogram according to the kind of materials distilled.

• Korean Journal of Plant Tissue Culture
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• v.26 no.3
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• pp.183-187
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• 1999

To establish an efficient screening system for new herbicides using plant cultured cells, responses of tobacco photomixotrophic cultured (PH) cells to various herbicides with different modes of action were surveyed by measuring the cell growth and ion conductivity in medium. The cells were cultured in Murashige and Skoog (MS) medium containing 0.7mg/L 2,4-D, 0.3mg/L kinetin and 30 g/L sucrose at $25^{\circ}C$ in the light (100 rpm). Chemicals were treated to suspension cultures of tobacco PH cells at the time of subculture. The cell growth and ion conductivity in the medium were investigated on 12 days after chemical treatment. The ion conductivity assay gave well correlated results to the cell growth inhibition data. The responses of tobacco PM cells were dependent on the modes of action of chemicals tested. Atrazine, an inhibitor of photosynthetic electron transport (PET), strongly inhibited both the cell membrane and cell growth ($IC_{50}$/, about 1 $\mu$M). Butachlor (an inhibitor of cell division), glufosinate (an inhibitor of amino acid biosynthesis), and fluridone (an inhibitor of carotenoid biosynthesis) showed a dose-dependent inhibition. However, Quinclorac, a herbicide with an auxin activity, did not affect the cell growth and ion leakage. These results suggested that tobacco PM cells is suitable materials for the simple screening of new herbicides such as PET, amino acid biosynthesis, ceil division inhibitors by measuring the cell growth and ion conductivity.

• Journal of Sensor Science and Technology
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• v.20 no.1
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• pp.35-39
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• 2011

A disposable electrochemical immunosensor system has been developed for the detection of herbicide in aqueous samples. Disposable screen printed carbon electrodes(SPCE) were used as basic electrodes and an enzyme, horseradish peroxidase (HRP), and anti-herbicide antibodies was immobilised on to the working electrode of SPCE by using avidin-biotin coupling reactions. An herbicide-glucose oxidase conjugates have been used for the competitive immunoreaction with sample herbicides. The enzymatic reaction between the conjugated glucose oxidase and glucose added generates hydrogen peroxide, which was reduced by the peroxidase immobilised. The latter process caused an electrical current change, due to direct re-reduction of peroxidase by a direct electron transfer mechanism, which was measured to determine the herbicides in the sample. The optimal operational condition was found to be: $20\;{\mu}gl-1$ deglycosylated avidin loading to the working electrode and working potential +50 mV vs. Ag/AgCl. The total assay time was 15 min after sample addition. The detection limits for herbicides, atrazine and simazine, were found to be 3 ppb and 10 ppb, respectively.

• YAKHAK HOEJI
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• v.44 no.5
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• pp.416-423
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• 2000

There is a growing concern that a wide variety of chemicals released into the environment can disrupt the endocrine system of fish, wildlife and humans. Endocrine disrupting chemicals (EDCs) include pesticides such as DDT lindane and atrazine, the food packaging chemicals, phthalates and bisphenol A, alkylphenol ethoxylate detergents and the chemical industry by-products, dioxins. Xenoestrogens in the environment have been argued about health risk, because of estrogen mimetic chemicals are exposed only small amounts to human. A number of in vivo and in vitro assays are now in use to assess the activity of xenoestrogens in the environment. A human breast cancer cell line (MCF-7) was used to develop in vitro screening assay for the detection of xenoestrogenic environmental pollutants. The E-SCREEN (MCF7-BUS) assay is proposed as a reliable, easy and rapid-to-perform method. To optimize and validate this method before it can be used routinely, several phenol compounds and pesticides suspected to be estrogenic were tested using I-SCREEN assay. The results showed that this method is a valuable tool for screening potential estrogen-mimicking environmental pollutants and quantitative determination of estrogeniciy.

• Bulletin of the Korean Chemical Society
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• v.24 no.4
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• pp.413-420
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• 2003

A gas chromatography/mass spectrometric assay method was developed for the simultaneous determination of neutral and bacis twenty-five disruptors $(ED_S)$ in frog and fish. Afther homogenization and sonication of 5 g of sample, purification was achieves in one step with a solid phase extraction procedure using silica gelflorisl. Eluton was performed with 50mL of acetone : n-hexane (1 : 9) solution. The eluate was concentrated to approximately 10uL and dissolves with 100 uL of hexane and analyzed by GC-MS (SIM). The peaks had good chromatographic properties and the extraction of these compounds from sample also gave relatively high recoveries with small variatoins. Detection limits were 0.1 ng/g for 4-nitrotoluene, benzophenone, hexachlorobenzene, atrazine, malathion, o,p-DDT, o,p-DDT and permethrin, and 0.2 ng/g for heptachlor epoxide, γ-chlordane, α-chlordane, p,p'-DDE, p,p'-DDD, cypermethrin and fenvalerate, and 0.3 ng/g for trifluralin, metribuzin, alachlor, dieldrin and p,p'-DDT, and 0.5 ng/g for heptachlor, aldrin and parathion, and 0.7 ng/g for endrin, and 0.8 ng/g for nitrofen. The recoveries were between 33 and 109%. The method was used to analyze twenty-five frogs and forty-six fishes fishes samples caught from various regions in Korea. Benzophenone was detected at concentration of up to 17.2 ng/g in frog or fish. Heptachlor, aldrin, γ-chlordane, p,p'-DDE, p,p'-DDD, endrin and o,p-DDD were detected at concentrations of 0.7-12.5 ng/g in frog or fish. Also significant leveles of dieldrin (up to 22.5 ng/g) were observed. The developed method may be valuable to be used to the national monitoring project of EDS in biota samples.

• BMB Reports
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• v.40 no.4
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• pp.511-516
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• 2007

A glutathione S-transferase (GST) related to the phi (F) class of enzymes only found in plants has been cloned from the Oryza sativa. The GST cDNA was cloned by PCR using oligonucleotide primers based on the OsGSTF5 (GenBank Accession No. $\underline{AF309382}$) sequences. The cDNA was composed of a 669-bp open reading frame encoding for 223 amino acids. The deduced peptide of this gene shared on overall identity of 75% with other known phi class GST sequences. On the other hands, the OsGSTF5 sequence showed only 34% identity with the sequence of the OsGSTF3 cloned by our previous study (Cho et al., 2005). This gene was expressed in Escherichia coli with the pET vector system and the gene product was purified to homogeneity by GSH-Sepharose affinity column chromatography. The expressed OsGSTF5 formed a homo-dimer composed of 28 kDa subunit and its pI value was approximately 7.8. The expressed OsGSTF5 displayed glutathione conjugation activity toward 1-chloro-2,4-dinitrobenzene and 1,2-epoxy-3-(p-nitrophenoxy)propane and glutathione peroxidase activity toward cumene hydroperoxide. The OsGSTF5 also had high activities towards the herbicides alachlor, atrazine and metolachlor. The OsGSTF5 was highly sensitive to inhibition by S-hexylGSH, benastatin A and hematin. We propose from these results that the expressed OsGSTF5 is a phi class GST and appears to play a role in the conjugation of herbicide and GPOX activity.

• Journal of Environmental Science International
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• v.16 no.4
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• pp.393-397
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• 2007

The sonolytic decomposition of NHCs(Nitrogen Heterocyclic Compounds), such as atrazine[6-chloro-N-ethyl-N'-(1-methylethyl)-1,3,5-triazine-2,4-diamine], simazine(6-chloro-N,N'-diethyl-1,3,5-triazine-2,4-diamine), trietazine(6-chloro-N,N,N'-triethyl-1,3, 5-triazine-2,4-diamine), in water was investigated at a ultrasound frequency of 200kHz with an acoustic intensity of 200W under argon and air atmospheres. The concentration of NHCs decreased with irradiation, indicating pseudo-first-order kinetics. The rates were in the range $1.06{\sim}2.07({\times}10^{-2}min^{-1})$ under air and $1.30{\sim}2.59({\times}10^{-2}min^{-1})$ under argon at a concentration of $200{\mu}M$ of NHCs. The rate of hydroxyl radicals(${\bullet}{OH}$) formation from water is $19.8{\mu}M\;min^{-1}$ under argon and $14.7{\mu}M\;min^{-1}$ under air in the same sonolysis conditions. The sonolysis of NHCs is effectively inhibited, but not completely, by the addition of t-BuOH(2-methyl-2-propanol), which is known to be an efficient ${\bullet}{OH}$ radical scavenger in aqueous sonolysis. This suggests that the main decomposition of NHCs proceeds via reaction with ${\bullet}{OH}$ radical; a thermal reaction also occurs, although its contribution is small. The addition of appropriate amounts of Fenton's reagent $[Fe^{2+}]$ accelerates the decomposition. This is probably due to the regeneration of ${\bullet}{OH}$ radicals from hydrogen peroxide, which would be formed from recombination of ${\bullet}{OH}$ radicals and which may contribute a little to the decomposition.

• Korean Journal Plant Pathology
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• v.12 no.2
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• pp.255-265
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• 1996

토양에 존재하는 진균인 Gliocladium virens는 식물병을 감소 또는 방제할 수 있는 생물학적인 특성에 의하여 G. virens는 지난 수십년간 실용가능성이 큰 생물학적 방제균(또는 길항균)으로 집중적으로 연구되었다. 이 균이 식물병의 발생을 감소시키는 생물적 방제효과는 항생작용, 중복기생, 근권에서의 생존과 집단번식, 뿌리표면에서의 정착 등에 의한 것으로 분류되고 있다. 특히, 항생물질인 gliotoxin, gliovirin, viridin 등은 Rhizoctonia solani 및/또는 Pythium spp. 등에 항생효과가 뚜렷하고, 식물병의 발생과 직접적인 상관관계를 나타내고 있어 G. virens의 식물병의 방제에 관련된 중요한 작용기작으로 제시되어 있다. 또한, 근권에서 이균의 생존과 집단증식 및 뿌리표면에서의 정착은 식물병의 방제와 상관관계를 나타낼 수 있는 중요한 작용기작으로 제시되고 있다. 그러나 이균이 R. solani 등에 기생하는 현상은 식물병의 생물적 방제의 직접적인 연관관계를 나타내고 있지 않다. G. virens을 이용의 생물적 방제효과를 증진시키기 위한 방법으로 다음과 같은 두 가지 방법을 들 수 있다. 첫째, 길항효과가 높은 G. virens 균주를 선발하기 위하여 여러 종류의 토양에서 길항력이 높은 G. virens의 선발이 지난 수십년간 진행되고 있다. 또한, 특정 길항효과를 발현하는 유전자를 G. virens의 염색체에 도입하고 이를 발현시킴으로써 생물적 방제효과를 증진시키는 것으로 이러한 방법은 1980년 후반부터 진행되고 있다. 둘째, G. virens의 길항효과가 최대의 효율로 발현될 수 있도록 최적의 미세환경을 갖추고 있으며 농민이 편리하게 사용할 수 있는 G. virens의 운송매체의 개발이 중요하다. 운송매체의 개발에 의한 'Glioguard'는 G. virens의 포자를 alginate 입자에 제형화한 것으로서 미국에서 시판되고 있다. Aldicarb, metalaxyl, atrazine 등의 농약을 분해할 수 있는 능력은 G. virens의 다른 생물적 특성중의 하나이다. 특히, parathion을 분해할 수 있는 Flavobacterium sp.의 유전자(opd)가 G. virens의 염색체에 도입되여 발현될 수 있는 방법이 제시되었으며, 이는 G. virens을 이용한 토양에서의 특정한 농약의 분해효율을 증진시킬수 있는 가능성을 제시한 것이다. 그러나, G. virens를 이용한 농약의 생물적 분해에 관한 연구는 기초단계로 평가되고 있으며, 포장에서 이를 실용화하기 위해서는 향후 지속적인 연구가 필요하다.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2003.11a
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• pp.171-176
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• 2003

The sonolytic decomposition of NHCs, such as atrazine［6-chloro-N-ethyl-N＇ -(1-methylethyl)-1,3,5-triazine-2,4-diamine］, simazine( 6-chloro-N,N＇ -diethyl-l ,3,5-triazine-2,4-diamine), trietazine(6-chloro-N,N,N＇-triethyl-l,3,5-triazine-2,4-diamine), in water was investigated at a ultrasound frequency of 200kHz with an acoustic intensity of 200W under argon and air atmospheres. The concentration of NHCs decreased with irradiation, indicating pseudo-first-order kinetics. The rates were in the range 1.06∼2.07 (x10/sup -3/ min/sup -1/) under air and 1.30∼2.59(x10/sup -3/ min/sup -1/)under argon at a concentration of 200μM of NHCs. The rate of hydroxyl radicals(·OH) formation from water is 19.8μM min/sup -1/ under argon and 14.7 μM min/sup -1/ under air in the same sonolysis conditions. The sonolysis of NHCs is effectively inhibited, but not completely, by the addition of t-BuOH(2-methyl-2-propanol), which is known to be an efficient ·OH radical scavenger in aqueous sonolysis. This suggests that the main decomposition of NHCs proceeds via reaction with ·OH radical; a thermal reaction also occurs, although its contribution is small. The addition of appropriate amounts of Fenton's reagent ［Fe/sup 2＋/］ accelerates the decomposition. This is probably due to the regeneration of ·OH radicals from hydrogen peroxide, which would be formed from recombination of ·OH radicals and which may contribute a little to the decomposition.

• Korean Journal of Weed Science
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• v.7 no.2
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• pp.186-199
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• 1987

This study was carried out to investigate the growth of Korean lawn grass (Zoysia japonica Steud.), penncross bentgrass (Agrostis palustris Huda) and seaside bentgrass (Agrostis spp.) under application of 21 pre- and post-emergence herbicides and the weeding effect of 14 annual and 4 perennial weeds with them for the purpose of the systematic chemical weed control in turf. The results obtained were as follows; 1. Napropamide, napropamide + triclopyr and benefin were safe for Korean lawn grass and two kinds of bentgrasses when they were treated at 4 and 25 days after transplanting of turfgrasses. Simazine, lenacil and bentazon inhibited the growth of bentgrasses, but not Korean lawn grass. 2. The preemergence application of simazine, benefin and napropamide + simazine showed excellent control for Digitaria sanguinalis, Cyperus amuricus, Chenopodium album, Portulaca oleracea and Centipeda minima. Lenacil was excellent for control of all the tested weeds except Chenopodium album, napropamide excellent for them except Cyperus amuricus and Portulaca oleraces, and bentazon good for them except Digitaria sanguinalis. When simazine was treated with either napropamide or triclopyr at preemergence of weeds, weeding effect increased without inhibition of lawn growth. 3. The postemergence application of mecoprop, bentazon, benefin + dicamba and benefin + mecoprop was safe to bentgrasses. All the tested postemergence herbicides except simazine + atrazine did not inhibit the growth of Korean lawn grass. 4. Other postemergence herbicides mecoprop and triclopyr were excellent for the control of Echinochloa crusgalli and those except benefin and mecoprop excellent for Kummerovia striata. Digitaria sanguinalis was controlled by treating with all the tested post emergence herbicides and Cyperus amuricus controlled only by bentazon. 5. The growth rates of bentgrasses treated with simazine, lenacil and napropamide + simazine were lower than that of hand-weeded check, and those of benefin, bentazon, napropamide, napropamide + triclopyr, stomp, bensulide and triclopyr were higher than that one when applied at spring season. Korean lawn grass growth appeared to be good under application of all the tested preemergence herbicides at spring. Lanacil and bentazone showed poor control of Echinochloa crusgalli, and bensulide showed poor control of Erigeron canadensis. Also, napropamide and bentazon were not good for Kummerovia striata control. However, at the respective rates of all the tested herbicides, these three weeds were greatly controlled by 85-100% of weeding effect. 6. At the application of autumn season, bentazon, napropamide, pendimethalin, benefin, napropamide + triclopyr, bensulide and triclopyr seemed to be safe against three kinds of turfgrasses. But simazine, napropamide + simazine inhibited the growth of bentgrasses except Korean lawn grass. In terms of weed control performance, triclopyr was poor for controlling Echinochloa crusgalli and bentazon and stomp for Poa annua, napropamide, benefin and bensulide for Stellaria medico. Stellaria uliginosa and Cerastium caespitosum were well controlled by all the tested preemergence herbicides. 7. Korean lawn grass was safe when paraquat and glyphosate were treated at the dormanant season of turfgrass. These herbicides showed excellent controll of Poa annua but poor control of perennials in order of Trifolium repens < Miscanthus sinensis < Calystegia japonica < Artemisia asiatica. 8. In field test, all of 19 herbicides seemed to be safe when treated at Korean lawn grass. All of 10 preemergence herbicides were excellent for controlling annual weeds, but poor for perennial ones. All of 9 postemergence herbicides showed a excellent control for broad-leaf weeds.