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1.
After feeding 2,4-D or atrazine in a diet to southern armyworm (Spodoptera eridania Cram.) larvae for three days, the effect on total content and activities of cytochrome P450 and on insecticide toxicity were determined. Both 2,4-D and atrazine induced cytochrome P450-catalyzed aldrin epoxidation (AE) and methoxyresorufin O-demethylatin (MROD). The 2,4-D was a more potent inducer for total cytochrome P450 content, whereas atrazine disproportionately increased AE. Both compounds increased MROD significantly. The apparent kinetic characteristics of AE indicates that 2,4-D and atrazine induced similar P450 isozymes (Km 8.78 and 7.80 μM, respectively), which may differ from the constitutive isozyme (Km 3.14 μM). The 2,4-D-induced cytochrome P450 contributed to decreased carbaryl and permethrin toxicity, whereas the atrazine-induced cytochrome P450 caused decreased parathion and permethrin toxicity. The carbaryl toxicity correlated directly with 2,4-D-induced total P450 content and activities but not with atrazine-induced changes. The 2,4-D and atrazine also induced nonspecific esterase activity which may contribute to permethrin detoxification. 相似文献
2.
Zlatina Naydenova Zoltan Urshev Evgeny Golovinsky Konstantin Grancharov 《Pest management science》1996,47(1):25-30
Fifteen pesticides, representatives of different chemical groups, were tested for their inhibitory effect on the glucuronidation of 4-nitrophenol (4-NP) and phenolphthalein (PPh) by rat liver microsomes. Three herbicides (simazine, chlorsulfuron, tribenuron-methyl), two insecticides (dioxacarb, carbaryl) and one fungicide (zineb) significantly decreased the UDP-glucuronosyltransferase (UDPGT) activity. The carbamate insecticide dioxacarb was found to be the most potent inhibitor, at 1 mM concentration suppressing 4-NP-UDPGT activity completely, and reducing by 55% the activity associated with the conjugation of PPh. One millimole simazine and carbaryl affected only 4-NP glucuronidation, while chlorsulfuron and zineb exerted a marked inhibition of both 4-NP and PPh conversion. Concentrations of 0·1 mM carbaryl, dioxacarb and zineb were still inhibitory against 4-NP-UDPGT, with zineb producing 40% inhibition of PPh glucuronidation. As a whole, UDPGT isoforms conjugating PPh were less sensitive to the agrochemicals tested. Kinetic studies with dioxacarb, chlorsulfuron and carbaryl revealed a mixed type of inhibition with respect to the acceptor substrate 4-NP, with apparentKi values of 70 μM , 120 μM and 160 μM , respectively. 相似文献
3.
为进一步完善全膜双垄沟播玉米栽培技术体系,采用大田随机区组试验法,研究了不同施肥水平下全膜双垄沟播玉米土壤酶活性及氮磷养分含量的动态变化情况。结果表明：在玉米生长前期,土壤脲酶、碱性磷酸酶、蔗糖酶活性以及碱解氮、速效磷含量均呈现快速增长趋势。脲酶、蔗糖酶、过氧化氢酶活性和碱解氮含量均在拔节期达到最大值,碱性磷酸酶活性和速效磷含量在抽雄期达到最大值。在玉米生长后期,各种土壤酶活性和氮磷养分含量又呈降低趋势。土壤脲酶活性与氮磷养分含量,土壤碱性磷酸酶活性与速效磷含量均存在显著或极显著正相关关系,土壤蔗糖酶活性与氮磷养分含量也存在显著的正相关关系,而土壤过氧化氢酶活性与氮磷养分含量之间,土壤碱性磷酸酶活性与碱解氮之间无显著相关关系。西北干旱半干旱地区全膜双垄沟播玉米种植密度确定为6．75×104株·hm-2时,最佳施肥量为纯N 210 kg·hm-2、P2O5168 kg·hm-2。 相似文献
4.
银川平原不同类型盐渍化土壤酶活性及其与土壤养分间相关分析研究 总被引：5，自引：1，他引：4
为了研究银川平原不同类型及程度盐碱地土壤酶活性及其分布特征,文中采用高锰酸钾滴定法、硫代硫酸钠滴定法及比色测定法和相关分析法研究了银川平原不同类型及盐渍化不同程度土壤酶活性及其与土壤养分间的相关关系。结果表明:随着碱化土壤pH值和盐化土壤全盐含量的增加,土壤过氧化氢酶、转化酶、碱性磷酸酶和脲酶活性均呈现逐渐降低的趋势(p<0.01)。土壤碱性磷酸酶活性表现为碱化土壤显著高于盐化土壤,过氧化氢酶、转化酶和脲酶活性在不同类型土壤间差异不显著。0-20cm深度土壤酶活性表现出明显的季节变化,碱化土壤碱性磷酸酶活性、盐化土壤过氧化氢酶活性表现8月>6月>9月;碱化盐化土壤转化酶活性、碱化土壤脲酶活性、盐化土壤碱性磷酸酶活性季节变化表现为随着取样时间的推移而逐渐增加,即9月>8月>6月。碱化、盐化土壤过氧化氢酶、转化酶、碱性磷酸酶和脲酶活性之间及其与土壤有机质、全氮、全磷、有效磷、全钾、碱解氮、速效钾含量之间有很好的正相关关系。 相似文献
5.
噻唑膦对冬暖式大棚土壤酶活性的影响 总被引：1，自引：1，他引：0
采用冬暖大棚土壤施药,研究了噻唑膦在田间条件下对蔬菜大棚土壤脲酶、蔗糖酶和过氧化氢酶活性的影响。结果表明,噻唑膦对土壤脲酶的影响较明显,各剂量处理均表现为激活-抑制-激活作用;对蔗糖酶以抑制作用为主,各剂量处理均表现为激活-抑制作用;对过氧化氢酶的影响相对较小,低剂量(10%颗粒剂有效成分含量2.25、3.00 kg/hm2)表现为激活作用,高剂量(6.00 kg/hm2)表现为抑制作用,且激活或抑制作用均不显著。施药50 d后,大棚土壤中脲酶和蔗糖酶活性都能逐渐恢复到正常水平。 相似文献
6.
John A. Cocks 《Pest management science》1975,6(3):259-265
The in vivo release of 14CO2 arising from decarbamoylation of [14C]-carbaryl (1-naphthyl methyl-[14C]-carbamate) injected into male and female Periplaneta americana, Leucophaea maderae, Gromphadorhina portentosa and Schistocerca gregaria was measured up to 50 nmol carbaryl/g body weight. The amount of 14CO2 released was proportional to the dose of [14C]-carbaryl injected and was similar for both sexes of each species. The KD50 values for carbaryl for each species did not correlate with their ability to decarbamoylate carbaryl. The degradation of carbaryl by this pathway is not therefore the limiting factor in determining the overall toxic effect of carbaryl in the four species studied. Decarbamoylation is inhibited by nitrogen in all four species. In P. americana the inhibition is virtually complete, in L. maderae, G. portentosa and S. gregaria the inhibition is 84%, 74% and 51% respectively. The results suggest the involvement of two enzymes, one of which is oxygen dependent. Decarbamoylation studies in air suggest the involvement of two enzymes with differing KM values. The involvement of aliesterases and mixed function oxidases in the decarbamoylation pathway(s) have not been established so far with this series of experiments. 相似文献
7.
Effects of glyphosate, paraquat, trifluralin and atrazine on activities of dehydrogenase, phosphatase and urease in one soil were measured. Only glyphosate at 21.6 kg/ha was found to inhibit the enzyme activities and generally the results were not statistically significant. Enzyme activity associated with micro-organisms proliferating in soil supplemented with lucerne meal was similarly not affected by the herbicides. Interpretation of results from enzyme activity measurements in soils treated with herbicides is discussed. It is proposed that effects of natural stress can be used to judge the relative importance of herbicide induced change. 相似文献
8.
Xiao Jian Xia Li Wang Yun Long Yu Jing Quan Yu 《Pesticide biochemistry and physiology》2006,86(1):42-48
The phytotoxicities of nine pesticides (paraquat, fluazifop-p-butyl, haloxyfop, flusilazole, cuproxat, cyazofamid, imidacloprid, chlorpyrifos, and abamectin) at practical dosages on photosynthesis were investigated in cucumber (Cucumis sativus L. cv. Jinyan No. 4) by gas exchange and chlorophyll fluorescent measurements. Plants treated with paraquat showed the severest phytotoxic symptom with the highest reduction in net photosynthetic rate (Pn), while other pesticides except flusilazole inhibited Pn to various degrees. The inhibition of Pn by cuproxat was accompanied by declines both in stomatal conductance (Gs) and intercellular CO2 concentration (Ci), whereas decreased Pn for the cyazofamid was associated with increased Ci. For other 6 pesticides, however, inhibition of Pn was accompanied by decrease in Gs, while Ci was increased or unaffected. Paraquat almost completely inhibited the maximal quantum efficiency of PSII (Fv/Fm), while other pesticides had no significant effect on Fv/Fm. Quantum efficiency of PSII (ΦPSII) was significantly reduced by paraquat, fluazifop-p-butyl, and chlorpyrifos and the reduction was mostly attributed to decrease in photochemical quenching coefficient (qP). In comparison, ΦPSII was not significantly affected by haloxyfop, flusilazole, cyazofamid, imidacloprid, and abamectin. Non-photochemical quenching (NPQ) was suppressed by paraquat and haloxyfop, while apparent upregulation was evident after exposure to other pesticides. Interestedly, inhibitions of Pn were alleviated by 24-epibrassinolide (EBR) pretreatment, as for the pesticides examined in this study except paraquat and flusilazole. EBR pretreatment also increased ΦPSII and qP. It is likely that EBR enhanced the resistance of cucumber seedlings to pesticides by increasing CO2 assimilation capacity and activities of antioxidant enzymes. 相似文献
9.
Troy D Anderson 《Pesticide biochemistry and physiology》2004,80(1):54-64
The acute toxicities of two organophosphorodithioate (dimethoate and disulfoton) and two organophosphorothioate (omethoate and demeton-S-methyl) insecticides were evaluated individually and in binary combination with the herbicide atrazine using fourth-instar larvae of the aquatic midge, Chironomus tentans. Atrazine alone up to 1000 μg/L did not show significant toxicity to the midges in a 48-h bioassay. However, atrazine concentrations as low as 1 μg/L in combination with dimethoate at EC25 (concentration to affect 25% of tested midges), 100 μg/L in combination with disulfoton (EC25), and 10 μg/L in combination with demeton-S-methyl (EC25) significantly enhanced the toxicity of each organophosphate insecticide. In contrast, atrazine concentrations of 10 μg/L and above in combination with omethoate (EC25) significantly decreased the toxicity of the insecticide. Biochemical analysis indicated that increased toxicity of dimethoate, disulfoton, and demeton-S-methyl in binary combination with atrazine correlated to the increased inhibition of acetylcholinesterase. Furthermore, cytochrome P450-dependent O-deethylation activity in the midges exposed to atrazine at 1000 μg/L was 1.5-fold higher than that in the control midges. Thus, atrazine appeared to induce cytochrome P450 monooxygenases in the midges. Elevated cytochrome P450 monooxygenase activity may increase the toxicities of dimethoate, disulfoton, and demeton-S-methyl by enhancing the oxidative activation of dimethoate into omethoate, and disulfoton and demeton-S-methyl into their sulfoxide analogs with increased anticholinesterase activity. In contrast, atrazine reduced the toxicity of omethoate possibly by enhancing the oxidative metabolic detoxification since omethoate does not require oxidative activation. 相似文献
10.
为明确异噁唑草酮对玉米根际土壤微生物碳、氮及酶活性的影响, 采用田间试验的方法, 以1倍、5倍和10倍田间推荐剂量为供试除草剂剂量, 测定了异噁唑草酮土壤封闭处理对玉米根际土壤微生物量碳、氮及土壤脲酶、过氧化氢酶、蔗糖酶、脱氢酶和中性磷酸酶活性的影响。结果表明:推荐剂量的异噁唑草酮对玉米根际土壤微生物量碳、氮含量无显著影响, 5倍和10倍推荐剂量的异噁唑草酮对玉米根际土壤微生物量碳、氮含量具有抑制作用。推荐剂量的异噁唑草酮对玉米根际土壤脲酶、过氧化氢酶和蔗糖酶影响较小, 5倍和10倍推荐剂量的异噁唑草酮对其具有明显的抑制作用。异噁唑草酮对土壤脱氢酶活性具有抑制作用, 且施用剂量越高, 抑制作用越强。异噁唑草酮对土壤中性磷酸酶活性的影响表现为前期促进, 后期抑制, 且施用剂量越大, 促进或抑制作用越强。研究表明:推荐剂量的异噁唑草酮对玉米根际土壤微生物量碳、氮及土壤脲酶、过氧化氢酶和蔗糖酶活性的影响较小, 但对土壤脱氢酶、中性磷酸酶活性有影响。 相似文献
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12.
Luca Fava Paola Bottoni Angela Crobe Anna Barra Caracciolo Enzo Funari 《Pest management science》2001,57(12):1135-1141
The metabolites of pesticides can contaminate groundwater and pose a risk to human health when this water is used for drinking. This paper reports the results of a laboratory study on aldicarb and its main metabolites, aldicarb sulfone and aldicarb sulfoxide. Aldicarb and its metabolites showed Koc values (6–31) which were lower than that of atrazine (55), indicating that they are very mobile in soil. They are less persistent than atrazine (DT50 = 25 days), with DT50 values from less than 1 day and up to 12 days. Aldicarb behaved as a non‐leacher, whereas its metabolites clearly showed the characteristics of leachers. Aged residue leaching experiments showed that aldicarb can occur at high concentrations in the leachate, together with its two metabolites. The leachate composition depends on the incubation time of the parent compound. Aldicarb and its metabolites can form various mixtures in groundwater on the basis of the time elapsing between the application of the insecticide and the first significant rainfall. This study confirms the characteristics of contaminants of aldicarb and especially its metabolites, as reported in the literature. © 2001 Society of Chemical Industry 相似文献
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14.
Dna J蛋白是Dna K/Hsp70的辅助分子伴侣,通过调节Hsp70的ATPase活性来影响蛋白复合体的合成与组装。为明确舞毒蛾Lymantria dispar的LdDnaJ1基因特性及对杀虫剂甲萘威的胁迫响应,通过克隆LdDnaJ1全长基因并运用实时荧光定量RT-PCR技术测定了甲萘威对其LdDnaJ1基因表达量的影响。结果表明,舞毒蛾Ld Dna J1全长基因开放阅读框为1 062 bp,编码353个氨基酸,分子质量为39.91 kD,理论等电点为5.65;舞毒蛾Dna J与柑橘凤蝶Papilio xuthus Dna J亲缘关系较近。甲萘威对舞毒蛾2龄幼虫24 h和48 h的致死中浓度LC50分别为74.04 mg/L和31.48mg/L。低剂量(LC_5、LC_(10)和LC_(30))甲萘威胁迫下,舞毒蛾2龄幼虫Ld Dna J1基因表达量均下调,LC_(30)甲萘威处理后72 h时LdDnaJ1基因表达量最低,仅为对照的15.70%。表明甲萘威可抑制舞毒蛾LdDnaJ1基因的表达,且呈现明显的时间和剂量效应。 相似文献
15.
丁草胺对土壤微生物数量和酶活性的影响 总被引：17，自引：2，他引：15
在模拟土壤生态系统中研究了丁草胺对土壤微生物数量和酶活性的影响。试验表明,低浓度(2 mg/kg)和中等浓度(4 mg/kg)丁草胺对微生物数量影响不大;而高浓度(10 mg/kg)处理则有明显抑制效应,但在21 d后也基本恢复到对照水平。丁草胺对土壤酸性磷酸酶、碱性磷酸酶、脲酶、蔗糖酶均产生了一定的抑制作用,并随浓度升高而增强,随着时间的延长,抑制作用逐渐消失,酶活性恢复至对照水平。丁草胺对土壤过氧化氢酶的影响与其他酶不同,表现出一定的刺激作用。 相似文献
16.
Rehmannia glutinosa (Gaertn.) Libosch. ex Fisch. & Mey. was very tolerant to paraquat (1,1′-dimethyl-4,4′-bipyridinium). The paraquat concentration required to reduce dry weight of R. glutinosa by 50% (GR50) was 24 mM , whereas a similar effect was obtained with 0·75 mM in Zea mays L. (maize, cv. Dekalb) and Glycine max (L.) Merr. (soybean, cv. Kwangkyo). When 1·5 mM paraquat in 10% aqueous extract of R. glutinosa was applied to maize and soybean, growth inhibition reached 24% and 7%, respectively, of the untreated control. Decreased activity of paraquat due to the extract also occurred in both leaf discs and chloroplasts of soybean. The total amount of [14C]paraquat absorbed into soybean leaves after 48 h was 34%, but it was reduced to 17% when the extract was added. Translocation of [14C]paraquat was also inhibited in the presence of the extract. In thin-layer chromatography (TLC) analysis using various solvent systems, Rf values of [14C]paraquat with the extract differed from those without the extract. The results suggested that the aqueous extract of R. glutinosa contained a substance which could nullify paraquat activity. © 1997 SCI. 相似文献
17.
The mobility and retention of atrazine and dicamba in six Atlantic Coastal Plain soils were estimated by soil thin-layer chromatography (soil-TLC). The soils studied were representative of the major agricultural regions in Delaware and were sampled, by horizon, to the water table. Four horizons from each profile were leached simultaneously with distilled water on one soil-TLC plate. Two values were obtained from each plate: the ratio of the distance traveled by the herbicide center of mass over that traveled by the solvent front (Rm), and a sorption distribution coefficient (Kd). The Rm values ranged from 0·06 to 0·94 for atrazine and from 0·80 to 0·94 for dicamba. Herbicide mobility was found to be greatest in coarse-textured soil horizons that contained low levels of organic matter, clay, and Fe and Al oxides. Correlation analysis indicated that effective cation exchange capacity, exchangeable acidity, exchangeable aluminum, and clay were useful predictive variables or both atrazine mobility and sorption. Organic matter was not useful for predicting soil-TLC derived sorption estimates; however, it was correlated to Kd-batch estimates. Distribution coefficients calculated from soil-TLC data were found to be in general agreement with Kd values obtained for the same soils by batch equilibrium techniques. The average Kd-soil-TLC values for atrazine and dicamba were 2·09(±2·24) and 0·03(±0·02), respectively. The ratio of the batch Kd to the soil-TLC Kd ranged from 0·1 to 19 (x̄=1·6, SD=3·8) for atrazine and from 2·9 to 38 (x̄=12·6, SD=8·7) for dicamba. Thus, although for some horizons agreement between the two methods was good, for other horizons significant discrepancies existed. It is suggested that the soil-TLC gives results under non-equilibrium conditions, whereas the batch procedure is, by definition, at quasi-equilibrium. These fundamental differences may account for the observed differences between the two methods. It is also suggested that, due to this difference, the soil-TLC procedure can provide additional information relevant to herbicide partitioning in the field environment that is not provided by traditional batch equilibrium techniques. © 1998 Society of Chemical Industry 相似文献
18.
The effect of 2,4-dichlorophenoxyacetic acid (2,4-D), 4-chloro-2-methylphenoxyacetic acid (MCPA), and their derivatives: phenol, 2,4-dichlorophenol (2,4-DCP), 2,4-dimethylphenol (2,4-DMP), and catechol on the activity of acetylcholinesterase (AChE, EC 3.1.1.7) in human erythrocytes was studied. Phenol, MCPA, and 2,4-DMP did not significantly change AChE activity in human erythrocytes (in vitro). Decrease of AChE activity was observed under the highest applied dose of 2,4-D—500 and 1000 ppm. Decrease of AChE activity exposed to 2,4-DCP and catechol was noted and depended on the doses of applied compounds. The relationship between activities and substrate concentrations (curves) was analyzed for reactions of acetylcholinesterase. Catalytic constants Km and Vmax were calculated from the Michaelis curve. Statistically significant decrease of Vmax and Km was observed in the activity of AChE incubated with 2,4-DCP and catechol, revealing mixed inhibition type of AChE inhibition (this compound may affect not only on enzyme but also on complex ES as well). 2,4-D decreases Vmax but do not change Km value, what reveals non-competitive type of AChE inhibition by this compounds. Non-competitive inhibition does not depend on the substrate concentrations but only on the inhibitor concentration and its Ki value, characterizes the affinity of inhibitors towards enzyme. In conclusion, changes of AChE activity upon 2,4-D, 2,4-DCP, and catechol are the consequences of direct interactions between compounds and the enzyme and indirect via membrane modification and increase of Reactive Oxygen Species. 相似文献
19.
为了探讨甜樱桃重茬土壤中有效养分以及酶活性的变化,在樱桃苗圃地分别从尚未栽种过甜樱桃苗、正茬、重茬区域采集土壤样品,测定土壤有效养分含量(NO3--N、NH4+-N、速效K、有效P及有效B等)和4种土壤酶(脲酶、过氧化氢酶、碱性磷酸酶以及蔗糖酶)的活性。结果表明:与樱桃正茬土壤相比,甜樱桃重茬土壤NO3--N、速效K、有效P、有效B、有效Zn、有效Fe、有效Cu、可交换性Mg含量、脲酶以及碱性磷酸酶活性含量显著降低;与正茬土壤相比重茬土壤中随着土层深度的增加,矿质元素含量(除有效Mn、Fe以及可交换性Ca含量外)和4种土壤酶活性显著降低,但可交换性Ca含量上升;樱桃重茬土壤有效养分比例失调,其中Ca/P、Ca/K及Ca/Zn严重失调,其中0~20 cm土层失调比例高达104.93%、140.45%和184.59%,20~40 cm土层失调比例分别为110.03%、178.42%以及144.47%,Zn/Mn和Zn/Mg失调较严重,失调比例高达50%以上。其中相关性分析表明:茬数与有效Mn含量呈线性极显著正相关;脲酶和碱性磷酸酶与速效K、有效P、有效B、有效Zn及有效Cu呈极显著正相关;蔗糖酶与速效K、有效P和有效Cu呈极显著正相关;脲酶、碱性磷酸酶和蔗糖酶与交换性Ca含量呈极显著负相关。总之,重茬土壤的有效养分含量以及土壤酶活性显著降低,养分比例失调。 相似文献
20.
Working with Malaysian agricultural soils, high Freundlich adsorption distribution coefficients (Kads(f)) were observed for paraquat (28·7 and 1419) and glyphosate (83·8 and 417) and lower values for 2,4-D (0·57 and 5·26) and lindane (2·65 and 14·1) in a sandy loam and a muck soil, respectively. Desorption of 2,4-D and lindane from the muck soil occurred. The adsorption of the pesticides was not affected by temperature (20°C/30°C), pH or addition of the pesticides as a mixture. Leaching of 2,4-D and lindane was evident under a high water influx (200 mm). Comparable results in the leaching of 2,4-D were observed between laboratory studies and a VARLEACH model prediction. © 1997 SCI. 相似文献