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1.
《Pesticide biochemistry and physiology》2009,95(2-3):49-54
Pyrethroid and organophosphate resistance-associated mutations have been recently reported in the whitefly Bemisia tabaci (Gennadius), a major pest of protected and outdoor crops worldwide. Here, we developed simple PCR–agarose gel visualization based assays for reliably monitoring the L925I and T929V pyrethroid resistance mutations in the B. tabaci para-type voltage gated sodium channel and the iAChE F331W organophosphate resistance mutation in the acetylcholinesterase enzyme ace1.PCR-RFLP assays were developed for detecting the L925I and the F331W resistance mutations. A highly specific PASA was developed for detecting the T929V mutation. The molecular diagnostic tools were used to monitor the frequency of the resistance mutations in a large number of field caught Q biotype B. tabaci from Crete (Greece), where both organophosphates and pyrethroids are extensively used. The F331W mutation was fixed in all field individuals examined. The pyrethroid resistance mutations were detected in high frequencies: 0.38 and 0.54 for L925I and T929V, respectively. The simple diagnostics are accurate and robust, to be used alongside classical bioassays to prevent ineffective insecticide applications, and for early identification of the spreading of resistant Q biotype populations into new regions around the globe. 相似文献
2.
Resistance to chlorpyriphos insecticide in Bemisia tabaci from a field population collected in Benin, West Africa was suggested with bioassay showing the presence of two sub-populations. Patterns of acetylcholinesterase (AChE) inhibition by the organophosphate chlorpyriphos-oxon were analyzed to estimate the number of possible genotypes with different sensitivity expected in three B. tabaci field populations collected in Benin. The analysis of inhibition patterns in these populations compared with four laboratory strains of B. tabaci using chlorpyriphos-oxon allowed the differentiation of three possible genotypes. In the reference strain SUD-S we detected two different acetylcholinesterases with different sensitivity to chlorpyriphos oxon suggesting the presence of two genes ace 1 and ace 2. The proportion of the insensitive enzyme (ace 2) was estimated to be 31%. In field populations we can detect two alleles at the same gene locus ace 1: one susceptible ace1S and one resistant ace1R. Both strains called Arizona University and Mexico-S2 have lost sensitive ace1S but the field populations from Benin clearly contained at least three genotypes confirming heterogeneous populations not completely resistant. 相似文献
3.
A field population of the rice stem borer (Chilo suppressalis Walker) with 203.3-fold resistance to triazophos was collected. After 8-generation of continuous selection with triazophos in laboratory, resistance increased to 787.2-fold, and at the same time, the resistance to isocarbophos and methamidophos was also enhanced by 1.9- and 1.4-fold, respectively, implying some cross-resistance between triazophos and these two organophosphate insecticides. Resistance to abamectin was slightly enhanced by triazophos selection, and fipronil and methomyl decreased. Synergism experiments in vivo with TPP, PBO, and DEM were performed to gain a potential indication of roles of detoxicating enzymes in triazophos resistance. The synergism results revealed that TPP (SR, 1.92) and PBO (SR 1.63) had significant synergistic effects on triazophos in resistant rice borers. While DEM (SR 0.83) showed no effects. Assays of enzyme activity in vitro demonstrated that the resistant strain had higher activity of esterase and microsomal O-demethylase than the susceptible strain (1.20- and 1.30-fold, respectively). For glutathione S-transferase activity, no difference was found between the resistant and the susceptible strain when DCNB was used as substrate. However, 1.28-fold higher activity was observed in the resistant strain when CDNB was used. These results showed that esterase and microsomal-O-demethylase play some roles in the resistance. Some iso-enzyme of glutathione S-transferase may involve in the resistance to other insecticides, for this resistant strain was selected from a field population with multiple resistance background. Acetylcholinesterase as the triazophos target was also compared. The results revealed significant differences between the resistant and susceptible strain. The Vmax and Km of the enzyme in resistant strain was only 32 and 65% that in the susceptible strain, respectively. Inhibition tests in vitro showed that I50 of triazophos on AChE of the resistant strain was 2.52-fold higher. Therefore, insensitive AChE may also involved in triazophos resistance mechanism of rice stem borer. 相似文献
4.
He Lin Xue Chuan-hua Wang Jin-jun Li Ming Lu Wen-cai Zhao Zhi-mo 《Pesticide biochemistry and physiology》2009,93(1):47-52
A Tetranychus cinnabarinus strain was collected from Chongqing, China. After 42 generations of selection with abamectin and 20 generations of selection with fenpropathrin in the laboratory, this T. cinnabarinus strain developed 8.7- and 28.7-fold resistance, respectively. Resistance to abamectin in AbR (abamectin resistant strain) and to fenpropathrin in FeR (fenpropathrin resistant strain) was partially suppressed by piperonyl butoxide (PBO), diethyl maleate (DEM) and triphenyl phosphate (TPP), inhibitors of mixed function oxidase (MFO), glutathione S-transferases (GST), and hydrolases, respectively, suggesting that these three enzyme families are important in conferring abamectin and fenpropathrin resistance in T. cinnabarinus. The major resistant mechanism to abamectin was the increasing activities of carboxylesterases (CarE), glutathione-S-transferase (GST) and mixed function oxidase (MFO), and the activity in resistant strain developed 2.7-, 3.4- and 1.4-fold contrasted to that in susceptible strain, respectively. The activity of glutathione-S-transferase (GST) in the FeR strain developed 2.8-fold when compared with the susceptible strain, which meant the resistance to fenpropathrin was related with the activity increase of glutathione-S-transferase (GST) in T. cinnabarinus. The result of the kinetic mensuration of carboxylesterases (CarE) showed that the structure of CarE in the AbR has been changed. 相似文献
5.
The cross-resistance and biochemical mechanism of the beet armyworm, Spodoptera exigua (Hübner), to spinosad was studied in the laboratory. S. exigua population were collected from Shanghai suburb. After five generations of selection, the resistance of S. exigua to spinosad increased 345.4 times compared with the susceptible strain. There was no cross-resistance between spinosad and fenvalerate, phoxim, methomyl, abamectin, and cyfluthrin. When the inhibitors, PBO, TPP, DEF, and DEM were used as synergist in the susceptible strain and resistant strain, the synergistic ratio was 0.7-, 0.5-, 1.0-, and 0.6- fold for the susceptible strain, and 9.8-, 1.5-, 2.6-, and 1.5-fold for the resistant strain, respectively. The results revealed that PBO had significant synergistic effect on the resistant strain. The activity in vitro of microsomal-O-demethylase and glutathione S-transferase in the resistant strain was 5.2- and 1.0-fold of the susceptible strain, respectively. The results implied that microsomal-O-demethylase might be important in conferring spinosad resistance in the S. exigua population. 相似文献
6.
Yu-Xin Chai 《Pesticide biochemistry and physiology》2007,88(2):197-202
The toxicological and biochemical characteristics of acetylcholinesterases (AChE) in the resistant and susceptible strains (SS) of Liposcelis bostrychophila were investigated. The two resistant strains were the dichlorvos-resistant strain (DDVP-R) and the phosphine-resistant strain (PH3-R) with resistance ratios of 22.36 and 4.51, respectively. Compared to their susceptible counterpart, the AChE activity per insect and the specific activity of AChE in DDVP-R and PH3-R were significantly higher. There were also significant kinetic differences between DDVP-R and PH3-R. The apparent Michaelis-Menten constant (Km) for acetylthiocholine iodide (ATChI) was obviously lower in SS than that in PH3-R, indicating a higher affinity to the substrate ATChI in the susceptible strains. The affinity for the substrate ATChI in DDVP-R and SS were not significantly different. The Vmax value of the PH3-R was significantly greater when compared to the Vmax for the SS suggesting a possible over expression of AChE in this resistant strain. The inhibition of AChE to insecticide exposure in vitro revealed that all six insecticides were inhibitory for the extracted AChE’s. Based on the I50 values, AChE of the SS were more sensitive to dichlorvos, paraoxon-ethyl, malaoxon and demeton-S-methyl than those of the two resistant strains. As for carbaryl and eserine, the PH3-R suggested a significantly higher I50s compared to the susceptible strain, while, no significant differences were found between SS and DDVP-R. 相似文献
7.
8.
Fipronil resistance mechanisms were studied between the laboratory susceptible strain and the selective field population of rice stem borer, Chilo suppressalis Walker in the laboratory. The borer population was collected from Wenzhou county, Zhejiang province. After five generations of selection, fipronil resistance ratio was 45.3-fold compared to the susceptible strain. Synergism experiments showed that the synergistic ratios of PBO, TPP and DEF on fipronil in susceptible and resistant strains of C. suppressalis were 7.55-, 1.93- and 2.91-fold, respectively, and DEM showed no obvious synergistic action on fipronil. Activities of carboxylesterase and microsomal-O-demethylase in the resistant strain were 1.89- and 1.36-fold higher that in susceptible strain, and no significant difference of glutathione-S-transferase activity was found between the resistant and susceptible strains. The Km and Vmax experiments also demonstrated that fipronil resistance of C. suppressalis was closely relative to the enhanced activities of carboxylesterase and microsomal-O-demethylase. Moreover, cross-resistance between fipronil and other conventional insecticides and the multiple resistant properties of the original Wenzhou’s population were also discussed. 相似文献
9.
Decreased acetylcholinesterase (AChE) sensitivity and metabolic detoxification mediated by glutathione S-transferases (GSTs) were examined for their involvement in resistance to acephate in the diamondback moth, Plutella xylostella. The resistant strain showed 47.5-fold higher acephate resistance than the susceptible strain had. However, the resistant strain was only 2.3-fold more resistant to prothiofos than the susceptible strain. The resistant strain included insects having the A298S and G324A mutations in AChE1, which are reportedly involved in prothiofos resistance in P. xylostella, showing reduced AChE sensitivity to inhibition by methamidophos, suggesting that decreased AChE1 sensitivity is one factor conferring acephate resistance. However, allele frequencies at both mutation sites in the resistant strain were low (only 26%). These results suggest that other factors such as GSTs are involved in acephate resistance. Expression of GST genes available in P. xylostella to date was examined using the resistant and susceptible strains, revealing no significant correlation between the expression and resistance levels. 相似文献
10.
A housefly strain, originally collected in 1998 from a dump in Beijing, was selected with beta-cypermethrin to generate a resistant strain (CRR) in order to characterize the resistance and identify the possible mechanisms involved in the pyrethroid resistance. The resistance was increased from 2.56- to 4419.07-fold in the CRR strain after 25 consecutive generations of selection compared to a laboratory susceptible strain (CSS). The CRR strain also developed different levels of cross-resistance to various insecticides within and outside the pyrethroid group such as abamectin. Synergists, piperonyl butoxide (PBO) and S,S,S-tributyl phosphorotrithioate (DEF), increased beta-cypermethrin toxicity 21.88- and 364.29-fold in the CRR strain as compared to 15.33- and 2.35-fold in the CSS strain, respectively. Results of biochemical assays revealed that carboxylesterase activities and maximal velocities to five naphthyl-substituted substrates in the CRR strain were significantly higher than that in the CSS strain, however, there was no significant difference in glutathione S-transferase activity and the level of total cytochrome P450 between the CRR and CSS strains. Therefore, our studies suggested that carboxylesterase play an important role in beta-cypermethrin resistance in the CRR strain. 相似文献
11.
Janet Hemingway 《Pesticide biochemistry and physiology》1985,23(3):309-313
Malathion resistance in Anopheles arabiensis from Sudan is monofactorially inherited and is expressed in the adults but not in the larvae. The resistance is suppressed by the esterase synergist, triphenylphosphate. Semipurification of the soluble esterase enzymes by Sephadex G-25 and Sephacryl S-200 gel filtration revealed no difference between the enzymes of the resistant and susceptible strains with α- or β-naphthylacetate (NA) with a fixed substrate concentration in either the adults or larvae. However, with the malathion-specific assay a second peak of activity was observed in the adult resistant strain which was not present in either the larvae of this strain or the larvae and adults of the susceptible strain. A corresponding threefold difference in the Km value for α-NA was also observed in the resistant adults over the range of this second peak, but there was no change in the Km with β-NA. 相似文献
12.
Andrew Y. Li John H. Pruett John E. George 《Pesticide biochemistry and physiology》2005,81(3):145-153
The San Roman strain of the southern cattle tick, Boophilus microplus, collected from Mexico was previously reported to have a high level of resistance to the organophosphate acaricide coumaphos. An oxidative detoxification mechanism was suspected to contribute to coumaphos resistance in this tick strain, as coumaphos bioassay with piperonyl butoxide (PBO) on larvae of this resistant strain resulted in enhanced coumaphos toxicity, while coumaphos assays with PBO resulted in reduced toxicity of coumaphos in a susceptible reference strain. In this study, we further analyzed the mechanism of oxidative metabolic detoxification with synergist bioassays of coroxon, the toxic metabolite of coumaphos, and the mechanism of target-site insensitivity with acetylcholinesterase (AChE) inhibition kinetics assays. Bioassays of coroxon with PBO resulted in synergism of coroxon toxicity in both the San Roman and the susceptible reference strains. The synergism ratio of PBO on coroxon in the resistant strain was 4.5 times that of the susceptible strain. The results suggested that the cytP450-based metabolic detoxification existed in both resistant and susceptible strains, but its activity was significantly enhanced in the resistant strain. Comparisons of AChE activity and inhibition kinetics by coroxon in both susceptible and resistant strains revealed that the resistant San Roman strain had an insensitive AChE, with a reduced phosphorylation rate, resulting in a reduced bimolecular reaction constant. These data indicate a mechanism of coumaphos resistance in the San Roman strain that involves both insensitive AChE and enhanced cytP450-based metabolic detoxification. 相似文献
13.
Ashraf O. Abd El-Latif 《Pesticide biochemistry and physiology》2010,96(3):155-159
Microplate assay technique for estimation of esterase activity in a single insect was used in combination with dose mortality bioassays to detect pyrethroid resistance in three strains of Helicoverpa armigera and to study the frequency of pyrethroid resistant individuals within the population of the same strain at two larval stages, third and fifth instar. The third and fifth instar larvae of the field strains i.e., Nagpur strain and Delhi strain that displayed high degree of resistance towards deltamethrin, had higher esterase activity compared to a susceptible laboratory strain. The frequency distribution of individuals with elevated esterase activity above 1.00 absorbance unit was correlated with the resistance level of the strains. The frequency of resistant individuals in the third instar larvae of Nagpur strain and Delhi strain were 29% and 23%, respectively compared to 4% in the susceptible strain. The resistant individuals in the resistant strains have markedly increased in the fifth instar larvae with a frequency distribution of 63% and 90% in Delhi strain and Nagpur strain, respectively, while only 14% of individuals was found to have elevated esterase activity in the susceptible strain. The results demonstrated the role of esterase in pyrethroid resistance in H. armigera. Microplate assay proved to be a rapid and reliable biochemical technique for monitoring of pyrethroid resistance in H. armigera. 相似文献
14.
Genetic studies of glutathione-dependent reactions were conducted with a diazinon-resistant house fly strain in which resistance is controlled primarily by genes on chromsome II. The resistant strain was crossed with a susceptible strain which had mutant markers on chromosomes II, III, and V, and the F1 was backcrossed to the susceptible strain. Glutathione transferase activities of the resultant eight phenotypes were measured using 3,4-dichloronitrobenzene, methyl iodide, and γ-benzene hexachloride as substrates. High levels of all these activities are controlled by gene(s) on chromosome II. Further analysis was made by introducing diazinon resistance into a susceptible strain via genetic crossing-over. Intermediate activity levels for 3,4-dichloronitrobenzene and methyl iodide conjugations were introduced along with intermediate levels of resistance. Assays of individual flies of the synthesized strain revealed they were heterogeneous for glutathione-dependent activities, consisting of individuals with low, intermediate, and high transferase activity. Based on these results, high levels of the glutathione-dependent enzymes are not a major biochemical mechanism responsible for diazinon resistance. It was also demonstrated that glutathione S-aryltransferase and S-alkyltransferase in the house fly, as measured with 3,4-dichloronitrobenzene and methyl iodide, are inseparable genetically and may, therefore, be the same enzyme. 相似文献
15.
Wheat aphid, Sitobion avenae (fabricius), is one of the most important wheat pests and has been reported to be resistant to commonly used insecticides in China. To determine the resistance mechanism, the resistant and susceptible strains were developed in laboratory and comparably studied. A bioassay revealed that the resistant strain showed high resistance to pirimicarb (RR: 161.8), moderate reistance to omethoate (32.5) and monocrotophos (33.5), and low resistance to deltamethrin (6.3) and thiodicarb (5.5). A biochemistry analysis showed that both strains had similar glutathione-S-transferase (GST) activity, but the resistant strain had 3.8-fold higher esterase activity, and its AChE was insensitive to this treatment. The I50 increased by 25.8-, 10.7-, and 10.4-folds for pirimicarb, omethoate, and monocrotophos, respectively, demonstrating that GST had not been involved in the resistance of S. avenae. The enhanced esterase contributed to low level resistance to all the insecticides tested, whereas higher resistance to pirimicarb, omethoate, and monocrotophos mainly depended on AChE insensitivity. However, the AChE of the resistant strain was still sensitive to thiodicarb (1.7-fold). Thus, thiodicarb could be used as substitute for control of the resistant S. avenae in this case. Furthermore, the two different AChE genes cloned from different resistant and susceptible individuals were also compared. Two mutations, L436(336)S in Sa.Ace1 and W516(435)R in Sa.Ace2, were found consistently associated with the insensitivity of AChE. They were thought to be the possible resistance mutations, but further work is needed to confirm this hypothesis. 相似文献
16.
Yuntao Feng Qingjun Wu Shaoli Wang Xiaoli Chang Wen Xie Baoyun Xu Youjun Zhang 《Pest management science》2010,66(3):313-318
BACKGROUND: B‐biotype Bemisia tabaci (Gennadius) has invaded China over the past two decades. To understand the risks and to determine possible mechanisms of resistance to thiamethoxam in B. tabaci, a resistant strain was selected in the laboratory. Cross‐resistance and the biochemical mechanisms of thiamethoxam resistance were investigated in the present study. RESULTS: A 66.3‐fold thiamethoxam‐resistant B. tabaci strain (TH‐R) was established after selection for 36 generations. Compared with the susceptible strain (TH‐S), the selected TH‐R strain showed obvious cross‐resistance to imidacloprid (47.3‐fold), acetamiprid (35.8‐fold), nitenpyram (9.99‐fold), abamectin (5.33‐fold) and carbosulfan (4.43‐fold). No cross‐resistance to fipronil, chlorpyrifos or deltamethrin was seen. Piperonyl butoxide (PBO) and triphenyl phosphate (TPP) exhibited significant synergism on thiamethoxam effects in the TH‐R strain (3.14‐ and 2.37‐fold respectively). However, diethyl maleate (DEM) did not act synergistically with thiamethoxam. Biochemical assays showed that cytochrome P450 monooxygenase activities increased 1.21‐ and 1.68‐fold respectively, and carboxylesterase activity increased 2.96‐fold in the TH‐R strain. However, no difference was observed for glutathione S‐transferase between the two strains. CONCLUSION: B‐biotype B. tabaci develops resistance to thiamethoxam. Cytochrome P450 monooxygenase and carboxylesterase appear to be responsible for the resistance. Reasonable resistance management that avoids the use of cross‐resistance insecticides may delay the development of resistance to thiamethoxam in this species. Copyright © 2009 Society of Chemical Industry 相似文献
17.
S.H.P.P. Karunaratne N.J. Hawkes H. Ranson 《Pesticide biochemistry and physiology》2007,88(1):108-113
The present status of pyrethroid resistance in vectors of malaria; Anopheles culicifacies and Anopheles subpictus, was tested in two malarious Districts, Anuradhapura and Trincomalee, of Sri Lanka. Both species were resistant to permethrin and susceptible to cypermethrin and cyfluthrin. An. subpictus were resistant to deltamethrin. λ-Cyhalothrin and etofenprox resistance was shown only by Anuradhapura An. subpictus. Although there were no differences among the populations for esterase and glutathione S-transferase activities, increased monooxygenase levels were found among Trincomalee populations. The voltage-gated sodium channel gene, the target site gene of pyrethroids, was partially sequenced to screen for mutations previously associated with insecticide resistance. The classic leucine to phenylalanine substitution, TTA to TTT, was detected in An. subpictus. It appears that both kdr type and monooxygenase resistance underlie pyrethroid resistance in these two malaria vectors of Sri Lanka. 相似文献
18.
Wei Dou 《Pesticide biochemistry and physiology》2009,94(1):10-14
Glutathione S-transferases (GSTs) catalyzing the conjugation of reduced glutathione (GSH) to a vast range of xenobiotics including insecticides were investigated in the psocid Liposcelis bostrychophila Badonnel. GSTs from susceptible and two resistant strains (DDVP-R for dichlorvos-resistant strain and PH3-R for phosphine-resistant strain) of L. bostrychophila were purified by glutathione-agarose affinity chromatography and characterized by their Michaelis-Menten kinetics towards artificial substrates, i.e., 1-chloro-2,4-dinitrobenzene (CDNB), in a photometric microplate assay. The specific activities of GSTs purified from two resistant strains were significantly higher than their susceptible counterpart. For the resistant strains, GSTs both showed a significantly higher affinity to the substrate GSH while a declined affinity to CDNB than those of susceptible strain. The inhibitory potential of ethacrynic acid was very effective with highest I50 value (the concentration required to inhibit 50% of GSTs activity) of 1.21 μM recorded in DDVP-R. Carbosulfan also exhibited excellent inhibitory effects on purified GSTs. The N-terminus of the purified enzyme was sequenced by Edman degradation, and the alignment of first 13 amino acids of the N-terminal sequence with other insect GSTs suggested the purified protein was similar to those of Sigma class GSTs. 相似文献
19.
Jintana Yanola Catherine Walton La-aied Prapanthadara 《Pesticide biochemistry and physiology》2010,96(3):127-131
Sodium channel mutations were investigated through nucleotide sequencing of three cDNA fragments amplified from permethrin resistant and susceptible Aedes aegypti from northern Thailand. There was a novel nucleotide substitution (T → G) at the second position of codon 1552 resulting in the replacement of Phenylalanine by Cysteine in segment 6 domain III. This amino acid was indicated by another study to involve an aromatic-aromatic contact between the sodium channel protein and the first aromatic ring of the pyrethroid alcohol moiety. Reciprocal crosses between the homozygous parental susceptible and resistant strains indicated that resistance was autosomal and incompletely recessive, and highly associated with the homozygous mutation. The bioassay of the F2 progeny, formed by backcrossing the F1 with the resistant parental strain, did not show a clear plateau curve across the range of doses, suggesting that resistance to permethrin was controlled by more than one gene locus. Other possible resistance mechanisms involved are discussed. 相似文献
20.
Jalal A Jazayeri 《Pesticide biochemistry and physiology》2004,80(1):1-11
Strains of sheep louse Bovicola ovis (Schrank) with various levels of resistance to pyrethroid and one strain with high degree of resistance to organophosphate (OP) insecticides were used to investigate the biochemical mechanisms of insecticide resistance, i.e., enhanced levels of general esterases, specific acetylcholinesterases (AChE), glutathione S-transferase (GST), and mixed function oxidases. Native gel electrophoresis combined with quantitative enzyme assays showed analogous expression profiles of several esterase isozymes in all the strains tested. The determination of the sensitivity of each esterase isozyme to five inhibitors (acetylthiocholine iodide, butyrylthiocholine iodide, paraoxon eserine sulfate, and pCMB) led to the identification of nine esterases in the B. ovis strain. Gel electrophoresis results are supported by enzyme assay studies where, except for the OP resistant strain, no differences in esterase activities were detected in all the pyrethroid resistant and susceptible strains assayed. Statistical analyses demonstrated that some strains have elevated GST activities compared to the susceptible reference strain. 相似文献