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11.
对利用酶抑制分光光度法检测蔬菜上有机磷和氨基甲酸酯类农药残毒的原理、最主要影响因子和存在的问题进行了探讨 ,重点分析了酶抑制分光光度法出现假阳性、负抑制率以及该方法不适用于检测韭菜等蔬菜中的有机磷和氨基甲酸酯类农药残留的原因 相似文献
12.
S.?Stankovi?Email author A.?Zabel M.?Kostic B.?Manojlovic S.?Rajkovic 《Journal of pest science》2004,77(1):11-15
Leptinotarsa decemlineata (Say), the Colorado potato beetle (potato beetle), is the most destructive potato pest in Serbia. Up to four pesticide treatments are necessary for its control. Insecticide resistance of the potato beetle in Serbia is well-investigated and documented, especially to organophosphates and carbamates. Toxicity of chlorpyriphos (organophosphates) and carbosulfan (carbamates) was investigated by topical application, using adults of the first generation from nine field populations. Adults of all populations possessed a certain level of resistance to both insecticides, with very low regression slopes (0.50–1.09 for chlorpyriphos and 0.57–0.85 for carbosulfan). Resistance ratios for chlorpyriphos ranged from 1.0 to 109.7 and from 1.0 to 52.8 for carbosulfan. There was no correlation between resistance to chlorpyriphos and carbosulfan. The key modes of resistance to organophosphates and carbamates are metabolism [overproduction of aliesterase (ALiE), a carboxylesterase] and altering the target site of acetylcholine esterase (AChE). Biochemical research of potato beetle resistance to organophosphates and carbamates, based on activity of ALiE and AChE, proved that the key mode of resistance to organophosphates was modification of ALiE and AChE to carbamates. Our results correspond to this research concerning the lack of correlation between resistances to these two insecticides. A certain level of resistance of the potato beetle to organophosphates and carbamates is widespread in Serbia. Different modes of resistance suggest the possibilities of control of this pest, such as choice of insecticide and insecticide rotation, wherever possible. 相似文献
13.
Thomas K. Walsh 《Pesticide biochemistry and physiology》2007,88(1):26-30
Lepeophtheirus salmonis is a copepod ectoparasite of wild and farmed salmonids and can cause considerable damage to infected fish. We have examined the effect of the organophosphate trichlorphon, which was one of the early treatments for sea lice as Neguvon® on L. salmonis. Suppression subtractive hybridisation was used to prepare a cDNA library enriched for cDNAs expressed in response to the organophosphate trichlorophon and using this technique a total of 33 cDNAs were found to be differentially regulated in response to organophosphate exposure. Sequence analysis of the cDNAs revealed that many were involved in cellular stress responses and or neurotoxicity. The expression of two of these cDNAs was confirmed to be up-regulated in response to trichlorophon. 相似文献
14.
Robyn J Russell Charles Claudianos Peter M Campbell Tara D Sutherland 《Pesticide biochemistry and physiology》2004,79(3):84-93
Interspecific comparisons of bioassay and biochemical data suggest two major patterns of target site resistance to carbamates and organophosphates. Pattern I resistance, which is generally more effective for carbamates, has been shown in two sub-species of mosquitoes to be due to a particular Gly-Ser mutation in the oxyanion hole within the active site of one of their two acetylcholinesterase enzymes. Intriguingly, different substitutions at the equivalent site confer organophosphate hydrolytic ability on other esterases responsible for metabolic resistance in some other species. In the case of the aphid, Myzus persicae, Pattern I resistance is due to a Ser-Phe mutation in the vicinity of the acyl pocket of acetylcholinesterase. Pattern II resistance is at least as effective for organophosphates as it is for carbamates and may even be specific to organophosphates in some cases. Molecular studies on this pattern of resistance in three higher Diptera show that it is due to changes that constrict the acetylcholinesterase active site gorge and limit binding of the insecticide to the catalytic residues at the base of the gorge. One case of Pattern II resistance in the mosquito, Culex tritaeniorhynchus, involves the same site near the acyl pocket of acetylcholinesterase, albeit a different substitution, as that involved in Pattern I resistance in M. persicae. 相似文献
15.
Melpomeni Tryfonos George Chaleplis George Theophilidis 《Pesticide biochemistry and physiology》2009,93(1):40-218
The effects of paraoxon and atrazine on the spontaneously beating auricle, isolated from the heart of Sparus aurata, were assessed. Paraoxon, 5 μM, eliminated the atria contraction within 28.4 ± 2.8 min, an effect which was fully reversed by 15 μM atropine, an antagonist of muscarinic cholinergic receptors. The IC50 was estimated to be 3.2 ± 1.5 μΜ. Atrazine, 50 and 100 μM, induced a 22.5 ± 3.2 and 32.9 ± 2.3% increase in the force of auricle contraction, caused by excitation of sympathetic synaptic terminals releasing adrenaline. This effect was reversed by 50 μM propranolol, a blocker of β-adrenoreceptors. The results have shown that both sympathetic and parasympathetic nerve terminals are activated by atrazine. Also, the auricle contraction is mainly under sympathetic control, while the frequency is dominated by cholinergic system. Finally, the detailed parameters of the auricle contraction estimated during exposure to specific pesticides, force, frequency, time-response curves and electromechanical coupling can be further used to assess and compare the toxic effects of other compounds, anticholinesterases for example, on the heart of the fish. 相似文献
16.
对利用酶抑制分光光度法检测蔬菜上有机磷和氨基甲酸酯类农药残毒的原理、最主要影响因子和存在的问题进行了探讨,重点分析了酶抑制分光光度法出现假阳性、负抑制率以及该方法不适用于检测韭菜等蔬菜中的有机磷和氨基甲酸酯类农药残留的原因 相似文献
17.
酶抑制分光光度法检测蔬菜上有机磷和氨基甲酸酯类农药残留的方法的研究 总被引：14，自引：0，他引：14
为了缩短用于蔬菜上有机磷和氨基甲酸酯类农药残留检测的酶抑制分光光度法的检测时间对抑制时间为10分钟时的最适条件进行了研究。提出了新的最适条件确定标准,即保证酶的活性保持在一定的水平的基础上（0.1333 min-1 ≤k1 ≤0.2667min-1 [ 1 ]）,选择抑制率(以甲胺磷为抑制剂)最高时的温度和pH值作为最适条件。确定了抑制时间为10分钟时的最适条件为：抑制温度47.0℃,pH值为7.7。进而在此最适条件下确定了新的检测结果判断标准：当酶抑制率≥58％时,蔬菜中含有某种有机磷或氨基甲酸酯类农药残留为阳性。 相似文献
18.
Maritza Reyes Béatrice CollangeMagali Rault Stefano CasanelliBenoît Sauphanor 《Pesticide biochemistry and physiology》2011,99(1):25-32
Despite the frequent and widespread applications of organophosphates against Cydia pomonella this species has developed low levels of resistance to this chemical group. Investigations concerning the mechanisms involved in resistance are scarce, and usually consider only one of the potential mechanisms. With the aim of a better understanding the resistance mechanisms and their possible interaction, four of these mechanisms were investigated simultaneously in one sensitive (Sv) and two resistant strains (Raz and Rdfb) of this insect. Resistant strains displayed an increased mixed function oxidase activity, whereas carboxylesterase activity varied upon the substrate used. The three strains had similar β-naphtyl acetate activity, and the hydrolysis of α-naphthyl acetate and p-nitrophenyl valerate was higher in the Sv strain. The p-nitrophenyl acetate activity was highest in the resistant strains and was strongly inhibited by azinphos and DEF. The Raz strain has a modified acetylcholinesterase (AChE), which resulted in a 0.7-, 3.2- and 21.2-fold decrease in the susceptibility to chlorpyriphos-ethyl-oxon, azinphos-methyl-oxon, and paraoxon-methyl, respectively. These combined resistance mechanisms only conferred to Raz a 0.6-, 7.9- and 3.1-fold resistance to the related insecticides. Organophosphates resistance in C. pomonella results from a combination of mechanisms including modified affinities to carboxylesterase substrates, and increased metabolisation of the insecticide. The apparent antagonism between increased functionalisation and reduced sensitivity of the AChE target is discussed. 相似文献
19.
Edison Barbieri Leandro Augusto Alves Ferreira 《Pesticide biochemistry and physiology》2011,99(3):209-214
Nile Tilapia (Oreochromis niloticus) juveniles were exposed to different concentrations of Folidol 600® in static toxicity tests. The 24, 48, 72 and 96 h LC50 values of Folidol 600® to O. niloticus were 17.82, 8.91, 4.00 and 2.70 mg L−1, respectively. The values of hematological parameters increased, and inhibition of cholinesterases activity (AChE, BChE and PChE) in plasma of fish exposed to the higher concentrations of pesticide reached 94%. Furthermore, the exposure of Tilapia to Folidol 600® caused an increase of 4%, 20% and 38.4% in oxygen consumption at 0.1, 0.5 and 1.0 mg L−1, respectively. However, exposure to 2.5, 5.0 and 10 mg L−1 caused a decrease of 33.6%, 35.2% and 42.4% in oxygen consumption relative to the control. The ammonium excretion of fish exposed to 0.0, 0.1, 0.5, 1.0, 2.5, 5.0 and 10.0 mg Folidol 600®/L was 0.12, 0.18, 0.30, 0.33, 0.37, 0.36 and 0.33 μg/g/min, i.e., 50%, 150%, 175%, 208%, 200% and 175% increase, respectively, relative to the control. 相似文献
20.
采用点滴法测定了山西晋中、临汾、运城地区麦长管蚜对５种有机磷杀虫剂的敏感性。结果表明，以ＬＤ５０值比较，晋中地区麦长管蚜的敏感性次序为氧化乐果＞辛硫磷＞马拉硫磷＞敌敌畏＞乐果；临汾地区的敏感性次序为马拉硫磷＞氧化乐果＞辛硫磷＞敌敌畏＞乐果；运城地区为马拉硫磷＞氧化乐果＞辛硫磷＞乐果＞敌敌畏。３个地区相比较，对各种杀虫剂的敏感性以运城最为敏感，其次为临汾、晋中地区。 相似文献