Response dynamics of three defense related enzymes in cotton leaves to the interactive stress of Helicoverpa armigera (Hübner) herbivory and omethoate application

In order to explore the response dynamics of the activities of defense related enzymes in cotton leaves towards the interactive stress of Helicoverpa armigera herbivory and omethoate application, the activities of phenylalanine ammonia-lyase（PAL）, lipoxygenase（LOX）, and polyphenol oxidase（PPO） were examined from 6 to 126 h after cotton leaves were treated 12 h of H. armigera herbivory, and then sprayed with 800 mg L–1 omethoate. The results showed that the changes in the activities of PAL, LOX and PPO that occured under the interactive stress of H. armigera herbivory and omethoate application reflected the interactive effects of the two stresses on cotton defense. The similarity between the response dynamics of PAL, LOX, and PPO activities in cotton leaves under the interactive stress and that under H. armigera herbivory treatment alone showed that the induction of H. armigera herbivory on the activities of PAL, LOX and PPO in cotton leaves played a leading role in the interactive effects, and the effect of omethoate application played only a minor role. A joint factor analysis was performed according to a method which has been used to analyze the joint toxicity of pesticides; this analysis sought to clarify if there was a synergistic, antagonistic, or additive effect on PAL, LOX, and PPO activity in cotton leaves resulting from the interactive H. armigera herbivory and omethoate treatment. In the interactive effect on the response of PAL activity in cotton leaves, antagonistic effects of the omethoate application towards H. armigera herbivory were observed at 6 and 12 h. Synergistic effects were then observed at 18 and 30 h. Antagonistic effects were observed from 54 to 78 h and synergistic effects were finally observed at 126 h. The correlation between H. armigera herbivory and omethoate application in the interactive effect on cotton defense responses of LOX activity also fluctuated from synergism to antagonism during the time course. In the interactive effect on PPO activity, only antagonism was observed between H. armigera herbivory and omethoate application. In the interactive stress of H. armigera herbivory and omethoate application on cotton defense responses, omethoate affected the defense responses of cotton to H. armigera herbivory by producing antagonistic and synergistic effects. These results will be useful to understand the relationship between host plant and herbivorous pest.

TiO_2/NaY Composite as Photocatalyst for Degradation of Omethoate

Photocatalytic activities of TiO2 and NaY zeolites-supported TiO2 were investigated with omethoate as a model pollutant.The physical and chemical states of NaY zeolite-supported TiO2 were evaluated via XRD,FTIR,BET and SEM.Photodegradation of omethoate was studied with H2O2 as oxidant and TiO2 supported on NaY zeolite as photocatalyst.Parameters involved in the photo-catalysis of omethoate,i.e.,the calcination temperature of the photocatalyst,initial omethoate concentration,the amount of TiO2 loaded on NaY zeolite,photocatalyst dosage and H2O2 concentration were investigated in detail.The results show that TiO2/NaY zeolite prepared by means of sol-gel method exhibited a good photocatalytic activity for the degradation of omethoate.Optimum conditions included the calcination temperature of photocatalyst 550℃,initial omethoate concentration 500 mg/L,the amount of TiO2 loaded on NaY zeolite 35%（mass fraction）,the amount of photocatalyst 5 g/L,H2O2 concentration 30 mL/L and an irradiation time of 180 min.The removal of omethoate was up to 93%.Kinetics parameters of the photocatalytic degradation of omethoate were measured and calculated.The result shows the kinetics of photocatalytic degradation of omethoate is first-order.

Determination of Omethoateby Cathodically SweepingOscillopolarography

Determination of omethoate by cathodically sweeping oscillopolarography is described. The product of the alkaline hydrolysis exhibited a sensitive second derivative wave at ?0.50 V (vs. SCE) in a 1.0 ×10?5mol/L sodium dodecylbenzene sulfonate (SDBS)+0.1 mol/L HAc-NaAc (pH 4.0) buffer. The peak current was linearly proportional to the concentration of omethoate in the range from 6.4×10?7 to 5.1×10?5 mol/L. The detection limit is 2.0×10?7 mol/L with the relative standard derivation (RSD) of 3.5%. The hydrolysis procedure and the electrode reaction were studied by voltammetry.

Effect of low-temperature plasma on the degradation of omethoate residue and quality of apple and spinach

Dielectric barrier corona discharge was developed to generate low-temperature plasma(LTP) to treat apple and spinach samples contaminated with omethoate. Experimental results showed that,after 20 min exposure, the degradation rate of omethoate residue in apple and spinach was(94.55± 0.01)% and(95.55 ± 0.01)%, respectively. When the treatment time was shorter than 20 min,the contents of moisture, vitamin C and beta-carotene were not affected by LTP. Exploration of related mechanisms suggested that LTP might destroy unsaturated double bonds of omethoate and produce phosphate ion, eventually leading to omethoate destruction. It is concluded that appropriate dosage of LTP can effectively degrade omethoate residue in fruits and vegetables without affecting their quality.

Omethoate-Induced Changes of (+)-δ-Cadinene Synthase Activity and Gossypol Content in Cotton Seedlings

The gene expression and activity of （＋）-δ-cadinene synthase during cotton development and in response to stress, as well as the spatial and temporal pattern of sesquiterpene biosynthesis, constitute one of chemical defense mechanisms in cotton plants. In order to explore the effects of omethoate on the cotton defense in relation to （＋）-δ-cadinene synthase and gossypol, effects of omethoate treatments on activity of （＋）-δ-cadinene synthase and gossypol content in cotton seedlings were investigated. Cotton seedlings treated with 400 mg L-1 omethoate exhibited a significant decrease in the specific activity of （＋）-δ-cadinene synthase from 12 to 120 h after treating when compared to the untreated control; significantly lower （＋）-δ-cadinene synthase activity was also observed in cotton seedlings treated with 200 mg L-1 omethoate from 72 to 120 h after treating; but for cotton seedlings treated with 100 mg L-1 omethoate, from 12 to 120 h after treating, no significant changes were observed for activity of （＋）-δ-cadinene synthase. The gossypol content in cotton seedlings treated with 100, 200 or 400 mg L-1 omethoate for different time periods showed no significant changes compared to that of the control. These results indicated that the activity of （＋）-δ-cadinene synthase in cotton seedlings in responses to exposure of omethoate at three concentrations for different time periods followed dose- and time-dependent responses to omethoate exposure. With omethoate as a chemical stress factor for cotton seedlings, the cotton defense in relation to the activity of （＋）-δ-cadinene synthase in cotton seedlings may be affected by omethoate application.

Effects of Omethoate on Liver Insulin Signaling in Mice

According to the report of the International Diabetes Federation, there were 382 million people affected with diabetes in 2013 and it is expected that this number will increase to 592 million by the year 2035;. Diabetes is caused due to the interaction between environmental and genetic factors;.

Aptamer-wrapped gold nanoparticles for the colorimetric detection of omethoate

Organophosphorous pesticide(OP) contamination has serious adverse effects on human health and the environment. Due to the toxicity of OPs and the threat presented by their accidental or intentional release in populated areas, the determination and monitoring of these OPs in food products and environment is of great importance. OPs are present in very small quantities and therefore, methods for their detection need to be highly sensitive and selective. Here, we aimed to develop a simple and selective aptamer-based colorimetric assay for the detection of omethoate, which is one of the commonly used OPs. The principle of the assay is that single-stranded DNA(ss DNA)-wrapped gold nanoparticles(Au NPs) are resistant to salt-induced aggregation. By employing an "artificial antibody" organophosphorous pesticide-binding aptamer(OBA) as the recognition element, aptamer-wrapped Au NPs(Au-apta) show high selectivity towards omethoate, resulting in the disconnection of aptamers from Au NPs and the aggregation of Au NPs. As there is a significant color change from the interparticle plasmon coupling during the aggregation of Au NPs, the established assay showed good linearity between 0.1 and 10 μmol/L, with a low detection limit of 0.1 μmol/L. Other OPs such as profenofos, phorate, and isocarbophos would not interfere with the detection of omethoate despite having similar structures. Thus, the colorimetric method shows potential for use in the detection of omethoate in real soil samples.

An Enzymatic Reaction Modulated Fluorescence-on Omethoate Biosensor Based on Fe_(3)O_(4)@GO and Copper Nanoparticles

The employing of organophosphorus pesticides(OPs),especially,the abusing of OPs,leads to residue accumulation,which causes immense effect to human health and environment.So,it is an urgent task to develop highly sensitive OPs’detection platforms.A novel enzyme modulated fluorescence-on sensor for sensitive detection of omethoate was successfully constructed,using AT-rich double-stranded DNA(dsDNA)templated copper nanoparticles(CuNPs)as the fluorescent signal and covalently combined magnetic Fe_(3)O_(4)and graphene oxide(GO)as the single-stranded DNA(ssDNA)adsorbent.The assay just associates acetylcholinesterase(AChE),one strand of dsDNA,acetylcholinein(ATCh),Fe_(3)O_(4)@GO and ascorbic acid(AA)/Cu^(2+).T6-1 and T6-2 are two strands single-stranded DNA(ssDNA)with the AT-rich sequence and continuous T bases at their two ends,respectively.In the aid of Hg^(^(2+)),they can hybridize into a blunt-ended dsDNA with one AT-rich end and one T-Hg^(^(2+))-T base pairs end.Once omethoate exists,it can inhibit AChE from transducing acetylcholinein(ATCh)into thiocholine(TCh).So,no TCh can snatch Hg^(^(2+))from T-Hg^(^(2+))-T base pairs in blunt-ended T6-1/T6-2.T6-1/T6-2 still keeps its integrity in blunt-ended dsDNA configuration,and hence the subsequently added Fe_(3)O_(4)@GO cannot absorb it.The remained blunt-ended T6-1/T6-2 in supernatant can act as the template of CuNPs to produce strong luminescence.The developed detection offers a signal-on omethoate detection,which can sensitively detect omethoate in the linear range of 5-200 nmol/L with a detection limit of 2.48 nmol/L.More importantly,it can detect omethoate in food and environmental samples,demonstrating high potential in real sample detection.

Photocatalytic degradation of omethoate using NaY zeolite-supported TiO_(2)

The degradation of omethoate was conducted using H_(2)O_(2) as oxidant,TiO_(2) supported on NaY zeolite as photocatalyst and a 300W lamp as light source.The effect of the calcination temperature of the photocatalyst,the amount of TiO_(2) loaded on NaY zeolite,the photocatalyst amount,the pH value and the radiation time on the degradation ratio of omethoate were investigated.The results show that TiO_(2)/NaY zeolite photocatalyst prepared by sol-gel method had good photocatalysis.The photo-catalytic optimum oxidationconditions of omethoate are as follows:the calcination temperature of the photocatalyst is 550℃,the amount of TiO_(2) loaded on NaY zeolite is 35.2 wt-%,the amount of photocatalyst is 5g/L,pH=8 and the radiation time is 180min.Under these conditions,the removal ratio of omethoate is up to 93%.

GC/Cl-MS-MS技术用于蔬菜中痕量甲胺磷、氧乐果和克百威的确认

近年来,甲胺磷、氧乐果、克百威等高毒药剂,因急性毒性问题,已被禁止在蔬菜和水果上使用[1].为确保人们的饮食安全,建立准确有效的残留分析方法势在必行.有机磷等农药在各种农作物样品中残留量很低,且样品中(如蔬菜、水果、茶叶等)的基质干扰较大,使得目标化合物易被基质掩盖.……

生物检材中氧乐果及其分解物的GC-MS分析

A method was established for the analysis of omethoate and it’s concomitants and decomposed product in biological samples by GC-MS.This method is rapid,reliable and accurate.

Sonochemical degradation of organophosphorus pesticide in dilute aqueous solutions

Ultrasonic irradiation was found to accelerate the rate of hydrolysis of omethoate in aqueous solution over the pH range of 2—12 Process parameters studied include pH, steady state temperature, concentration, and the type of gases. Greater than 96% hydrolysis was observed in 30 minutes through this process and the rate of destruction increased with the help of more soluble and low thermal inert gas. So with Krypton, omethoate was found to undergo rapid destruction as compared with Argon. In the presence of ultrasound, the observed first order rate of hydrolysis of omethoate is found to be independent of pH. The formation of transient supercritical water(SCW) appears to be an important factor in the acceleration of chemical reactions in the presence of ultrasound. A detailed chemical reaction mechanism for omethoate destruction in water was formulated. Experimental results and theoretical kinetic mechanism demonstrated that the most of the omethoate undergo destruction inside the cavitating holes. A very less effect of temperature on the degradation of omethoate within a temperature range of 20—70℃ proves that a small quantity of omethoate undergoes secondary destruction in the bulk liquid.

A Highly Efficient ZrO2 Nanoparticle Based Electrochemical Sensor for the Detection of Organophosphorus Pesticides

A sensitive electrochemical method for square-wave voltammetric detection of organophosphate （OP） com- pounds was developed based on zirconia （ZrO2） nanoparticles modified electrode. The electrode was fabricated us- ing electrochemical deposition and characterized by scanning electron microscopy （SEM）, which confirmed the successful formation of nanoparticles. Due to the strong affinity of ZrO2 with the phosphoric group, OPs can strongly bind to the surface of ZrO2 nanoparticles （ZrO2NPs）. Under optimized operational conditions, SWV was employed for Omethoate （a model of OP compounds） detection with 5 min absorption, which showed a wide detec- tion range from 98.5 pmoloL-x to 985 nmol·L^1, with a detection limit as low as 52.5 pmol·L^-1. This electrochemi- cal sensor has good selectivity, stability and reproducibility, and great potential in the detection of OP compounds in agriculture area.