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João Palermo-neto - One of the best experts on this subject based on the ideXlab platform.
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Effects of type II pyrethroid Cyhalothrin on peritoneal macrophage activity in rats
Toxicology, 2005Co-Authors: D.abbud Righi, João Palermo-netoAbstract:Abstract Synthetic type II pyrethroids induce anxiety, immunosuppressive or, alternatively, immunostimulatory effects in laboratory animals. Macrophages are known to be key elements in cellular immune responses. The present study was designed to investigate the in vivo effects of Cyhalothrin (0.6, 1.0 and 3.0 mg/kg/once daily for 7 days) on macrophage activity. The in vitro effects of Cyhalothrin (100 nM, 1 and 10 μM) were also analyzed to verify a possible direct action of this pyrethroid on macrophage. Results showed that in vivo Cyhalothrin treatment: (1) decreased macrophage spreading and phagocytosis indexes; (2) decreased macrophage nitric oxide (NO) production; (3) did not change spontaneous or PMA-induced macrophage H2O2 release. The no effect level dose (NOEL) obtained for Cyhalothrin on macrophage activity was 0.6 mg/kg/day. In-vitro data showed that Cyhalothrin decreased (1) macrophage NO production and (2) macrophage spontaneus and PMA-induced H2O2 releases. The present results were explained through an indirect action for Cyhalothrin on macrophage activity via hypothalamic pituitary adrenals (HPA) axis activation. A direct effect for Cyhalothrin on macrophage, most probably through an action on Na+ membrane channels, was also suggested. Finally, it is possible that both direct and indirect mechanisms would be involved with Cyhalothrin effects on macrophage activity.
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Behavioral effects of type II pyrethroid Cyhalothrin in rats
Toxicology and Applied Pharmacology, 2003Co-Authors: D.abbud Righi, João Palermo-netoAbstract:Synthetic pyrethroids such as Cyhalothrin are extensively used in agriculture for the control of a broad range of ectoparasites in farm animals. It has been suggested that type II pyrethroids might induce anxiogenic-like effects in laboratory animals. The present study was undertaken to investigate a possible anxiogenic-like outcome of Cyhalothrin in rats. Adult male rats were orally dosed for 7 days with 1.0, 3.0, or 7.0 mg/kg/day of Cyhalothrin, present in a commercial formulation (Grenade Coopers do Brazil S.A.). The neurobehavioral changes induced by Cyhalothrin as well as those produced on corticosterone serum levels were measured 24 h after the last treatment. Picrotoxin (1.0 mg/kg) was also acutely used as a positive control for anxiety. Results showed that Cyhalothrin: (1) induced some signs and symptoms of intoxication that included salivation, tremors, and liquid feces; (2) reduced total locomotor activity in the open-field; (3) reduced the percentage of time spent in open-field central zones; (4) increased immobility time in the open-field; (5) reduced the percentage of time spent in plus-maze open arms exploration; (6) reduced the time spent in social interactions, and (7) increased the levels of serum corticosterone. The behavioral changes reported for Cyhalothrin (3.0 mg/kg/day) were similar of those induced by picrotoxin. The no effect level dose obtained for Cyhalothrin in this study was 1.0 mg/kg/day. These results provide experimental evidence that Cyhalothrin induces anxiety-like symptoms, with this effect being dose-related. Thus, anxiety must be included among the several signs and symptoms of pesticide intoxication.
Xiwu Gao - One of the best experts on this subject based on the ideXlab platform.
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Overexpression of cytochrome P450s in a lambda-Cyhalothrin resistant population of Apolygus lucorum (Meyer-Dür)
2018Co-Authors: Congai Zhen, Yao Tan, Ling Miao, Xiwu GaoAbstract:The mirid bug, Apolygus lucorum Meyer-Dür, has been an important pest of cotton crop in China, and is primarily controlled with insecticides, such as pyrethroids. To elucidate the potential resistant mechanisms of A. lucorum to lambda-Cyhalothrin, a series of biological, biochemical, and molecular assays were conducted in the reference (AL-S) and lambda-Cyhalothrin-resistant (AL-R) populations. Comparison of the molecular target of pyrethroid insecticides, voltage-gated sodium channel, revealed that there were no mutation sites in the resistant population, indicating target insensitivity is not responsible for increased resistance of AL-R to lambda-Cyhalothrin. Furthermore, the synergism assays and the activities of detoxification enzymes were performed to determine detoxification mechanism conferring the lambda-Cyhalothrin resistance. In the tested synergists, the piperonyl butoxide had the highest synergism ratio against lambda-Cyhalothrin, which was up to five-fold in both populations. In addition, the result also showed that only cytochrome P450 had significantly higher O-deethylase activity with 7-ethoxycoumarin (1.78-fold) in AL-R population compared with AL-S population. Seven cytochrome P450 genes were found to be significantly overexpressed in the resistant AL-R population compared with AL-S population. Taken together, these results demonstrate that multiple over-transcribed cytochrome P450 genes would be involved in the development of lambda-Cyhalothrin resistance in AL-R population.
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Uptake of quercetin reduces larval sensitivity to lambda-Cyhalothrin in Helicoverpa armigera
Journal of Pest Science, 2018Co-Authors: Chengyu Chen, Xueyan Shi, Nicolas Desneux, Peng Han, Weiyu Yan, Siyi Wang, Xuguo Zhou, Xiwu GaoAbstract:Quercetin, one of the most abundant dietary flavonoids, is widely present in nature. In this study, the effects of quercetin ingestion on Helicoverpa armigera larvae growth and its sensitivity to lambda-Cyhalothrin were assessed. The median lethal concentration (LC50) value of lambda-Cyhalothrin to quercetin-fed H. armigera larvae was 2.39-fold higher than the control, suggesting a reduced sensitivity to lambda-Cyhalothrin. Piperonyl butoxide (PBO) treatment effectively synergized lambda-Cyhalothrin efficacy in quercetin-fed H. armigera larvae with a synergistic ratio of 2.36. Moreover, the growth of H. armigera larvae was inhibited by the quercetin uptake. To understand the reduced sensitivity to lambda-Cyhalothrin, we measured the enzymatic activity of cytochrome P450 monooxygenases (P450s), as well as transcriptional responses of three P450s genes in quercetin-fed H. armigera larvae. We found that cytochrome P450 monooxygenases involved in the observed lambda-Cyhalothrin tolerance in quercetin-fed H. armigera. After fed on quercetin for 48 h, 7-ethoxycoumarin-O-deethylase (ECOD) activity was significantly elevated in quercetin-fed H. armigera larvae; meanwhile, the expression level of CYP6B6, CYP6B8 and CYP321A1 was up-regulated. In conclusion, P450s played a crucial role in the metabolic adaptation of H. armigera larvae to its host plant's secondary metabolites as well as synthetic insecticides. The reduced lambda-Cyhalothrin sensitivity in quercetin-fed H. armigera larvae suggested that previous exposure to the host plant-derived quercetin is likely to compromise the efficacy of pyrethroid insecticides.
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Elevated carboxylesterase activity contributes to the lambda-Cyhalothrin insensitivity in quercetin fed Helicoverpa armigera (Hubner)
PLoS ONE, 2017Co-Authors: Chengyu Chen, Ying Liu, Xueyan Shi, Nicolas Desneux, Peng Han, Xiwu GaoAbstract:Quercetin as one of the key plant secondary metabolite flavonol is ubiquitous in terrestrial plants. In this study, the decrease in sensitivity to lambda-Cyhalothrin was observed in quercetin-fed Helicoverpa armigera larvae. In order to figure out the mechanisms underlying the decreased sensitivity of H. armigera larvae to lambda-Cyhalothrin by quercetin induction, the changes in carboxylesterase activity and in-vitro hydrolytic metabolic capacity to lambda-Cyhalothrin were examined. The LC50 value of quercetin-fed H. armigera larvae to lambda-Cyhalothrin showed 2.41-fold higher than that of the control. S, S, S-Tributyl phosphorotrithioate (DEF) treatment showed a synergism effect on lambda-Cyhalothrin toxicity to quercetin-fed H. armigera. Moreover, the activity of carboxylesterase was significantly higher in quercetin-fed H. armigera larvae after fed on quercetin for 48 h. The in-vitro hydrolytic metabolic capacity to lambda-Cyhalothrin in quercetin-fed H. armigera larvae midgut was 289.82 nmol 3-PBA/mg protein/min, which is significant higher than that in the control group (149.60 nmol 3-PBA/mg protein/min). The elevated CarE enzyme activity and corresponding increased hydrolytic metabolic capacity to lambda-Cyhalothrin in quercetin-fed H. armigera contributed to the enhanced tolerance to lambda-Cyhalothrin.
D.abbud Righi - One of the best experts on this subject based on the ideXlab platform.
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Effects of type II pyrethroid Cyhalothrin on peritoneal macrophage activity in rats
Toxicology, 2005Co-Authors: D.abbud Righi, João Palermo-netoAbstract:Abstract Synthetic type II pyrethroids induce anxiety, immunosuppressive or, alternatively, immunostimulatory effects in laboratory animals. Macrophages are known to be key elements in cellular immune responses. The present study was designed to investigate the in vivo effects of Cyhalothrin (0.6, 1.0 and 3.0 mg/kg/once daily for 7 days) on macrophage activity. The in vitro effects of Cyhalothrin (100 nM, 1 and 10 μM) were also analyzed to verify a possible direct action of this pyrethroid on macrophage. Results showed that in vivo Cyhalothrin treatment: (1) decreased macrophage spreading and phagocytosis indexes; (2) decreased macrophage nitric oxide (NO) production; (3) did not change spontaneous or PMA-induced macrophage H2O2 release. The no effect level dose (NOEL) obtained for Cyhalothrin on macrophage activity was 0.6 mg/kg/day. In-vitro data showed that Cyhalothrin decreased (1) macrophage NO production and (2) macrophage spontaneus and PMA-induced H2O2 releases. The present results were explained through an indirect action for Cyhalothrin on macrophage activity via hypothalamic pituitary adrenals (HPA) axis activation. A direct effect for Cyhalothrin on macrophage, most probably through an action on Na+ membrane channels, was also suggested. Finally, it is possible that both direct and indirect mechanisms would be involved with Cyhalothrin effects on macrophage activity.
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Behavioral effects of type II pyrethroid Cyhalothrin in rats
Toxicology and Applied Pharmacology, 2003Co-Authors: D.abbud Righi, João Palermo-netoAbstract:Synthetic pyrethroids such as Cyhalothrin are extensively used in agriculture for the control of a broad range of ectoparasites in farm animals. It has been suggested that type II pyrethroids might induce anxiogenic-like effects in laboratory animals. The present study was undertaken to investigate a possible anxiogenic-like outcome of Cyhalothrin in rats. Adult male rats were orally dosed for 7 days with 1.0, 3.0, or 7.0 mg/kg/day of Cyhalothrin, present in a commercial formulation (Grenade Coopers do Brazil S.A.). The neurobehavioral changes induced by Cyhalothrin as well as those produced on corticosterone serum levels were measured 24 h after the last treatment. Picrotoxin (1.0 mg/kg) was also acutely used as a positive control for anxiety. Results showed that Cyhalothrin: (1) induced some signs and symptoms of intoxication that included salivation, tremors, and liquid feces; (2) reduced total locomotor activity in the open-field; (3) reduced the percentage of time spent in open-field central zones; (4) increased immobility time in the open-field; (5) reduced the percentage of time spent in plus-maze open arms exploration; (6) reduced the time spent in social interactions, and (7) increased the levels of serum corticosterone. The behavioral changes reported for Cyhalothrin (3.0 mg/kg/day) were similar of those induced by picrotoxin. The no effect level dose obtained for Cyhalothrin in this study was 1.0 mg/kg/day. These results provide experimental evidence that Cyhalothrin induces anxiety-like symptoms, with this effect being dose-related. Thus, anxiety must be included among the several signs and symptoms of pesticide intoxication.
Vinay K. Khanna - One of the best experts on this subject based on the ideXlab platform.
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Cholinergic Dysfunctions and Enhanced Oxidative Stress in the Neurobehavioral Toxicity of Lambda-Cyhalothrin in Developing Rats
Neurotoxicity Research, 2012Co-Authors: Reyaz W. Ansari, Rajendra K. Shukla, Rajesh Singh Yadav, Kavita Seth, Aditya B. Pant, Dhirendra Singh, Ashok K. Agrawal, Fakhrul Islam, Vinay K. KhannaAbstract:This study is focused on understanding the mechanism of neurobehavioral toxicity of lambda-Cyhalothrin, a new generation type II synthetic pyrethroid in developing rats following their exposure from post-lactational day (PLD)22 to PLD49 and investigate whether neurobehavioral alterations are transient or persistent. Post-lactational exposure to lambda-Cyhalothrin (1.0 or 3.0 mg/kg body weight, p.o.) affected grip strength and learning activity in rats on PLD50 and the persistent impairment of grip strength and learning was observed at 15 days after withdrawal of exposure on PLD65. A decrease in the binding of muscarinic–cholinergic receptors in frontocortical, hippocampal, and cerebellar membranes associated with decreased expression of choline acetyltransferase (ChAT) and acetylcholinesterase (AChE) in hippocampus was observed following exposure to lambda-Cyhalothrin on PLD50 and PLD65. Exposure to lambda-Cyhalothrin was also found to increase the expression of growth-associated protein-43 in hippocampus of rats on PLD50 and PLD65 as compared to controls. A significant increase in lipid peroxidation and protein carbonyl levels and decreased levels of reduced glutathione and activity of superoxide dismutase, catalase, and glutathione peroxidase in brain regions of lambda-Cyhalothrin exposed rats were distinctly observed indicating increased oxidative stress. Inhibition of ChAT and AChE activity may cause down-regulation of muscarinic–cholinergic receptors consequently impairing learning activity in developing rats exposed to lambda-Cyhalothrin. The data further indicate that long-term exposure to lambda-Cyhalothrin at low doses may be detrimental and changes in selected behavioral and neurochemical end points may persist if exposure to lambda-Cyhalothrin continues.
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Involvement of dopaminergic and serotonergic systems in the neurobehavioral toxicity of lambda-Cyhalothrin in developing rats
Toxicology letters, 2012Co-Authors: Reyaz W. Ansari, Rajendra K. Shukla, Rajesh Singh Yadav, Kavita Seth, Aditya B. Pant, Dhirendra Singh, Ashok K. Agrawal, Fakhrul Islam, Vinay K. KhannaAbstract:Abstract In view of extensive uses of lambda-Cyhalothrin, a new generation type II synthetic pyrethroid, human exposure is quite imminent. The present study has therefore been carried out to investigate effect of lambda-Cyhalothrin on brain dopaminergic and serotonergic systems and functional alterations associated with them. Post-lactational exposure to lambda-Cyhalothrin (1.0 mg/kg or 3.0 mg/kg body weight, p.o.) from PD22 to PD49 caused a significant decrease in the motor activity and rota-rod performance in rats on PD50 as compared to controls. Decrease in motor activity in lambda-Cyhalothrin treated rats was found to persist 15 days after withdrawal of exposure on PD65 while a trend of recovery in rota-rod performance was observed. A decrease in the binding of 3 H-Spiperone, known to label dopamine-D2 receptors in corpus striatum associated with decreased expression of tyrosine hydroxylase (TH)-immunoreactivity and TH protein was observed in lambda-Cyhalothrin treated rats on PD50 and PD65 compared to controls. Increase in the binding of 3 H-Ketanserin, known to label serotonin-2A receptors in frontal cortex was observed in lambda-Cyhalothrin exposed rats on PD50 and PD65 as compared to respective controls. The changes were more marked in rats exposed to lambda-Cyhalothrin at a higher dose (3.0 mg/kg) and persisted even 15 days after withdrawal of exposure. The results exhibit vulnerability of developing rats to lambda-Cyhalothrin and suggest that striatal dopaminergic system is a target of lambda-Cyhalothrin. Involvement of serotonin-2A receptors in the neurotoxicity of lambda-Cyhalothrin is also suggested. The results further indicate that neurobehavioral changes may be more intense in case exposure to lambda-Cyhalothrin continues.
Marianne A Soares - One of the best experts on this subject based on the ideXlab platform.
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detrimental sublethal effects hamper the effective use of natural and chemical pesticides in combination with a key natural enemy of bemisia tabaci on tomato
Pest Management Science, 2020Co-Authors: Marianne A Soares, Geraldo Andrade Carvalho, Mateus R Campos, Luis C Passos, Marcelo M Haro, Anneviolette Lavoir, Antonio Biondi, Lucia ZappalaAbstract:Background Bemisia tabaci (Hemiptera: Aleyrodidae) represents one of the greatest threats to agricultural crops. Chemical control is the primary tool used in integrated pest management (IPM) programs. However, release of the predator Nesidiocoris tenuis (Hemiptera: Miridae) on tomato plants is a highly recommended control tactic. The objective of this study was to evaluate the efficacy of a commercial borax plus citrus oil (BCO) product against B. tabaci in the presence and absence of N. tenuis. The synthetic insecticide lambda-Cyhalothrin was used as a positive control. We also evaluated the sublethal effects of BCO on the behavior and predation rate of N. tenuis. Results Our results demonstrated that BCO, alone and at its maximum recommended field rate for B. tabaci, was not effective in controlling the pest under laboratory conditions. Application of BCO simultaneous with N. tenuis release did not reduce the increase in the B. tabaci population. Effective control of B. tabaci was achieved using only N. tenuis. However, synthetic lambda-Cyhalothrin pyrethroid, used here as a control, caused high pest mortality and led to on-site extinction of N. tenuis, which did not occur for insects exposed to BCO. Lambda-Cyhalothrin and BCO significantly affected the foraging behavior of N. tenuis, reducing the predation rate, especially following exposure to lambda-Cyhalothrin. Conclusion The insecticide lambda-Cyhalothrin achieved satisfactory results in suppressing B. tabaci, but was harmful to N. tenuis. Additionally, lambda-Cyhalothrin and BCO affected predator behavior. © 2020 Society of Chemical Industry.
