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1.
Molecules ; 26(12)2021 Jun 13.
Artigo em Inglês | MEDLINE | ID: mdl-34199157

RESUMO

The influence of p-terphenyl polyketides 1-3 from Aspergillus candidus KMM 4676 and cerebroside flavuside B (4) from Penicillium islandicum (=Talaromyces islandicus) against the effect of neurotoxins, rotenone and paraquat, on Neuro-2a cell viability by MTT and LDH release assays and intracellular ROS level, as well as DPPH radical scavenging activity, was investigated. Pre-incubation with compounds significantly diminished the ROS level in rotenone- and paraquat-treated cells. It was shown that the investigated polyketides 1-3 significantly increased the viability of rotenone- and paraquat-treated cells in two of the used assays but they affected only the viability of paraquat-treated cells in the LDH release assay. Flavuside B statistically increased the viability of paraquat-treated cells in both MTT and LDH release assays, however, it increased the viability of rotenone-treated cells in the LDH release assay. Structure-activity relationships for p-terphenyl derivatives, as well as possible mechanisms of cytoprotective action of all studied compounds, were discussed.


Assuntos
Aspergillus/química , Citoproteção/efeitos dos fármacos , Glicoesfingolipídeos/farmacologia , Neuroblastoma/tratamento farmacológico , Fármacos Neuroprotetores/farmacologia , Neurotoxinas/toxicidade , Policetídeos/farmacologia , Animais , Linhagem Celular Tumoral , Sobrevivência Celular , Herbicidas/toxicidade , Inseticidas/toxicidade , Camundongos , Neuroblastoma/metabolismo , Neuroblastoma/patologia , Fármacos Neuroprotetores/química , Paraquat/toxicidade , Policetídeos/química , Espécies Reativas de Oxigênio , Rotenona/toxicidade
2.
Ecotoxicol Environ Saf ; 221: 112452, 2021 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-34198186

RESUMO

Helicoverpa armigera (cotton bollworm) is one of the most destructive pests worldwide. Due to resistance to Bacillus thuringiensis and conventional insecticides, an effective management strategy to control this pest is urgently needed. Spinosad, a natural pesticide, is considered an alternative; however, the mechanism underlying the developmental effects of sublethal spinosad exposure remains elusive. In this study, the mechanism was examined using an insect model of H. armigera. Results confirmed that exposure to sublethal spinosad led to reduced larval wet weight, delayed larval developmental period, caused difficulty in molting, and deformed pupae. Further investigation demonstrated that exposure to sublethal spinosad caused a significant decrease in 20E titer and increase in JH titer, thereby leading to the discordance between 20E and JH titers, and consequently alteration in the expression levels of HR3 and Kr-h1. These results suggested that sublethal spinosad caused hormonal disorders in larvae, which directly affect insect development. Our study serves as a reference and basis for the toxicity evaluation of spinosad on molting and pupation in insect metamorphosis, which may contribute to identifying targets for effective control of cotton bollworm.


Assuntos
Inseticidas/toxicidade , Macrolídeos/toxicidade , Mariposas/efeitos dos fármacos , Animais , Combinação de Medicamentos , Larva/efeitos dos fármacos , Muda/efeitos dos fármacos , Mariposas/crescimento & desenvolvimento , Pupa/efeitos dos fármacos
3.
J Agric Food Chem ; 69(29): 8110-8119, 2021 Jul 28.
Artigo em Inglês | MEDLINE | ID: mdl-34270249

RESUMO

Chlorfenapyr is widely used as an insecticide/miticide. Tralopyril, the active metabolite of chlorfenapyr, is used as an antifouling biocide in antifouling systems, and negatively affects aquatic environments. However, it is unclear whether tralopyril is a metabolite of chlorfenapyr in aquatic vertebrates, and there is little data on the bioaccumulation and toxicity of chlorfenapyr to aquatic vertebrates. In this study, the bioaccumulation and elimination of chlorfenapyr in zebrafish were assessed, and tralopyril, the active metabolite of chlorfenapyr, was determined. The effects of chronic exposure to chlorfenapyr on zebrafish liver and brain oxidative damage, apoptosis, immune response, and metabolome were investigated. These results showed that chlorfenapyr has a high bioaccumulation in zebrafish, with bioaccumulation factors of 864.6 and 1321.9 after exposure to 1.0 and 10 µg/L chlorfenapyr for 21 days, respectively. Chlorfenapyr at these concentrations also rapidly accumulated in zebrafish, reaching 615.5 and 10336 µg/kg on the second and third days of exposure, respectively. Chlorfenapyr was degraded to tralopyril in zebrafish; therefore, both chlorfenapyr and tralopyril should be considered when evaluating the risk of chlorfenapyr to aquatic organisms. In addition, chronic exposure caused oxidative damage, apoptosis, and immune disorders in zebrafish liver. Chronic exposure also altered the levels of endogenous metabolites in liver and brain. After 9 days of depuration, some indicators of oxidative damage, apoptosis, and immunity returned to normal levels, but the concentration of endogenous metabolites in zebrafish liver was still altered. Overall, these results provide useful information for evaluating the toxicity and environmental fate of chlorfenapyr in aquatic vertebrates.


Assuntos
Inseticidas , Poluentes Químicos da Água , Animais , Bioacumulação , Inseticidas/toxicidade , Estresse Oxidativo , Piretrinas , Poluentes Químicos da Água/toxicidade , Peixe-Zebra
4.
Artigo em Inglês | MEDLINE | ID: mdl-34199797

RESUMO

The overuse of synthetic pesticides in plant protection strategies has resulted in numerous side effects, including environmental contamination, food staff residues, and a threat to non-target organisms. Several studies have been performed to assess the pesticidal effects of plant-derived essential oils and their components, as partially safe and effective agents, on economically important pests. The essential oils isolated from Satureja species are being used in medicinal, cosmetic, and food industries. Their great potential in pest management is promising, which is related to high amounts of terpenes presented in this genus. This review is focused on the acute and chronic acaricidal, insecticidal, and nematicidal effects of Satureja essential oil and their main components. The effects of eighteen Satureja species are documented, considering lethality, repellency, developmental inhibitory, and adverse effects on the feeding, life cycle, oviposition, and egg hatching. Further, the biochemical impairment, including impairments in esterases, acetylcholinesterase, and cytochrome P450 monooxygenases functions, are also considered. Finally, encapsulation and emulsification methods, based on controlled-release techniques, are suggested to overcome the low persistence and water solubility restrictions of these biopesticides. The present review offers Satureja essential oils and their major components as valuable alternatives to synthetic pesticides in the future of pest management.


Assuntos
Acaricidas , Repelentes de Insetos , Inseticidas , Óleos Voláteis , Satureja , Acaricidas/toxicidade , Feminino , Humanos , Inseticidas/toxicidade , Óleos Voláteis/toxicidade
5.
Braz J Biol ; 83: e244647, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34190758

RESUMO

The essential oil of citronella (Cymbopogon winterianus) has several biological activities, among them the insect repellent action. Some studies showed that cinnamic acid esters can be applied as natural pesticides, insecticides and fungicides. In this context, the objective of the present work was to evaluate the production of esters from citronella essential oil with cinnamic acid via enzymatic esterification. Besides, the essential oil toxicity before and after esterification against Artemia salina and larvicidal action on Aedes aegypti was investigated. Esters were produced using cinnamic acid as the acylating agent and citronella essential oil (3:1) in heptane and 15 wt% NS 88011 enzyme as biocatalysts, at 70 °C and 150 rpm. Conversion rates of citronellyl and geranyl cinnamates were 58.7 and 69.0% for NS 88011, respectively. For the toxicity to Artemia salina LC50 results of 5.29 µg mL-1 were obtained for the essential oil and 4.36 µg mL-1 for the esterified oils obtained with NS 88011. In the insecticidal activity against Aedes aegypti larvae, was obtained LC50 of 111.84 µg mL-1 for the essential oil of citronella and 86.30 µg mL-1 for the esterified oils obtained with the enzyme NS 88011, indicating high toxicity of the esters. The results demonstrated that the evaluated samples present potential of application as bioinsecticide.


Assuntos
Aedes , Cymbopogon , Repelentes de Insetos , Inseticidas , Óleos Voláteis , Animais , Esterificação , Inseticidas/toxicidade , Larva , Óleos Voláteis/toxicidade
6.
Environ Sci Process Impacts ; 23(7): 1006-1017, 2021 Jul 21.
Artigo em Inglês | MEDLINE | ID: mdl-34105591

RESUMO

The development of nanoagrochemicals has attracted much attention in the last decade to overcome the recent agricultural and environmental challenges associated with the intensive usage of insecticides. Herein, nanostructured calcium borate materials with hierarchical sea urchin-like microspheres and microblocks have been synthesized by a facile hydrothermal method. The insecticidal activity of CaB2O4 and its synergistic combination with cholinesterase-inhibiting insecticides are explored against Spodoptera littoralis (S. littoralis) for the first time via a feeding bioassay protocol. The insecticidal efficacy of sea urchin-like microspheres (CB-A) is estimated to be LC50 = 207 mg L-1 which is two-fold higher than that of microblocks (CBM-A) with LC50 = 406 mg L-1 after eleven days of exposure. The synergistic combination of the CB-A sample with methomyl and chlorpyrifos increases the toxicity to 2.4 and 2.6-fold higher than that of the individual insecticides, respectively. Significantly, sea urchin-like CaB2O4 microspheres cause physical damage to the external insect's cuticle layer, which consequently enhances the uptake of organic insecticides. Our results revealed that calcium borate micro-/nano-structures can be employed as a multifunctional nanoagrochemical in various agricultural programs for S. littoralis control and decrease the usage of cholinesterase-inhibiting insecticides.


Assuntos
Inseticidas , Animais , Boratos , Compostos de Cálcio , Colinesterases , Inseticidas/toxicidade , Larva , Microesferas , Ouriços-do-Mar , Spodoptera
7.
Ecotoxicology ; 30(6): 1007-1016, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34110545

RESUMO

The diamondback moth (Plutella xylostella L.), is an economic pest of cruciferous plants worldwide, which causes great economic loss to cruciferous plants production. However, the pest has developed resistance to insecticides. One of such insecticides is chlorantraniliprole. The study of the mechanisms underlying resistance is key for the effective management of resistance. In this study, a comparative proteomics approach was used to isolate and identify various proteins that differed between chlorantraniliprole-susceptible and -resistant strains of P. xylostella. Eleven proteins were significantly different and were successfully identified by MALDI-TOF-MS. Metabolism-related proteins accounted for the highest proportion among the eleven different proteins. The function of the PxGST2L protein was validated by RNAi. Knockdown of PxGST2L reduced the GST activity and increased the toxicity of chlorantraniliprole to the diamondback moth. The resistance ratio of diamondback moth to chlorantraniliprole was reduced from 1029 to 505. The results indicated that PxGST2L is partly responsible for chlorantraniliprole insecticide resistance in DBM. Our finding contributes to the understanding of the mechanism underlying resistance to chlorantraniliprole in the DBM, to develop effective resistance management tactics.


Assuntos
Inseticidas , Mariposas , Animais , Glutationa Transferase/genética , Resistência a Inseticidas/genética , Inseticidas/toxicidade , Larva , Mariposas/genética , ortoaminobenzoatos/toxicidade
8.
Ecotoxicology ; 30(6): 1056-1070, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34152527

RESUMO

Agriculture insecticides are used against insect pest species, but are able to change community structure in contaminated habitats, and also the genetic pool of exposed individuals. In fact, the latter effect is a relevant tool to in situ biomonitoring of pollutant contamination and impact, besides its practical economic and management concerns. This takes place because the emergence of individuals with resistance to insecticides is particularly frequent among insect pest species and usually enhances insecticide overuse and crop losses. Pest insects of global prominence such as whiteflies are a focus of attention due to problems with insecticide resistance and association with endosymbionts, as the case of the invasive putative species Bemisia tabaci MEAM1. The scenario is particularly complex in the Neotropics, where insecticide use is ubiquitous, but whose spatial scale of occurrence is usually neglected. Here we explored the spatial-dependence of both phenomena in MEAM1 whiteflies recording resistance to two widely used insecticides, lambda-cyhalothrin and spiromesifen, and endosymbiont co-occurrence. Resistance to both insecticides was frequent exhibiting low to moderate frequency of lambda-cyhalothrin resistance and moderate to high frequency of spiromesifen resistance. Among the prevailing whitefly endosymbionts, Wolbachia, Cardinium and Arsenophonus were markedly absent. In contrast, Hamiltonella and Rickettsia prevailed and their incidence was correlated. Furthermore, Rickettsia endosymbionts were particularly associated with lambda-cyhalothrin susceptibility. These traits were spatially dependent with significant variation taking place within an area of about 700 Km2. Such findings reinforce the notion of endosymbiont-associated resistance to insecticides, and also of their local incidence allowing spatial mapping and locally-targeted mitigation.


Assuntos
Hemípteros , Inseticidas , Animais , Humanos , Incidência , Resistência a Inseticidas , Inseticidas/toxicidade , Simbiose
9.
Ecotoxicology ; 30(6): 1150-1160, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34165677

RESUMO

Bradysia odoriphaga is a major insect pest that infests Chinese chive in northern China. Clothianidin is a second-generation neonicotinoid insecticide that is commonly used against B. odoriphaga. In this study, the effect of sublethal clothianidin concentrations (LC5 and LC10) on key biological characteristics of B. odoriphaga was investigated using an age-stage, two-sex life table method. Bioassays results showed that clothianidin exhibited high toxicity against B. odoriphaga with LC50 of 1.898 mg L-1 following 24 h exposure. The developmental duration of larvae was significantly increased when exposed to the LC5 (0.209 mg L-1) and LC10 (0.340 mg L-1) of clothianidin. No significant effects were observed on the pupal stage, adult pre-oviposition period (APOP), total pre-oviposition period (TPOP), and mean longevities of male and female. The oviposition period and fecundity of B. odoriphaga were reduced in clothianidin-treated groups. Moreover, key demographic parameters, including the intrinsic rate of increase (r), finite rate of increase (λ), and net reproductive rate (R0), were significantly decreased by the LC5 and LC10 of clothianidin, while no effects were noted on mean generation time (T). Overall, this study showed that sublethal concentrations of clothianidin have a detrimental effect on B. odoriphaga developmental period, fecundity, and life table parameters. Therefore, clothianidin has the potential to suppress the population of B. odoriphaga even at sublethal concentrations.


Assuntos
Cebolinha-Francesa , Dípteros , Inseticidas , Animais , China , Demografia , Feminino , Fertilidade , Guanidinas , Inseticidas/toxicidade , Larva , Masculino , Neonicotinoides/toxicidade , Tiazóis
10.
Environ Sci Technol ; 55(13): 9087-9096, 2021 07 06.
Artigo em Inglês | MEDLINE | ID: mdl-34106693

RESUMO

Bifenthrin (BF) is a widely used pyrethroid that has been frequently detected in surface waters. Previous studies indicated that BF had antiestrogenic activity in zebrafish embryos but estrogenic activity in posthatch fish. To determine whether age-related differences in metabolism contribute to the endocrine effects in developing fish, embryos from zebrafish and Japanese medaka were exposed to BF before and after liver development. Since the commercial mixture of BF is an isomer-enriched product containing two enantiomers (1R-cis-BF and 1S-cis-BF), enantioselective metabolism was also evaluated. The estrogenic metabolite, 4-hydroxybifenthrin (4-OH-BF) was identified in zebrafish embryos, and formation was higher in animals after liver development (>48 hpf). Treatments with ß-glucuronidase indicated that 4-OH-BF underwent conjugation in embryos. Formation was reduced by cotreatment of the cytochrome P450 (CYP450) inhibitor, ketoconazole. Formation of 4-OH-BF was greater when treated with 1R-cis-BF compared to the S-enantiomer. However, metabolites were not observed in medaka embryos. These data indicate enantioselective oxidation of BF to an estrogenic metabolite occurs in zebrafish embryos and, since it is increased after liver development, may partially explain estrogenic activity observed in older animals. The lack of activity in medaka suggests species-specific effects with BF metabolism and may influence risk assessment strategies in wildlife.


Assuntos
Inseticidas , Oryzias , Piretrinas , Poluentes Químicos da Água , Animais , Inseticidas/toxicidade , Piretrinas/toxicidade , Estereoisomerismo , Poluentes Químicos da Água/toxicidade , Peixe-Zebra
11.
Pestic Biochem Physiol ; 176: 104879, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34119222

RESUMO

Cytochrome P450 monooxygenases (P450s) and UDP-glycosyltransferases (UGTs) are major detoxifying enzymes that metabolize plant toxins and insecticides. In the present study, the synergists of piperonyl butoxide, sulfinpyrazone and 5-nitrouracil significantly increased cyantraniliprole and α-cypermethrin toxicity against the resistant strain. The transcripts of UGT341A4, UGT344B4, UGT344D6, UGT344J2 and UGT344M2 increased significantly in the CyR strain compared with the susceptible strain. Among these upregulated genes (including P450s), CYP6CY7 and UGT344B4 were highly expressed in the midgut. Transgenic expression of the P450 and UGT genes in broad body tissues in Drosophila melanogaster indicated that the expression of CYP380C6, CYP4CJ1, UGT341A4, UGT344B4 and UGT344M2 is sufficient to confer cyantraniliprole resistance, and CYP380C6, CYP6CY7, CYP6CY21, UGT341A4 and UGT344M2 are related to α-cypermethrin cross-resistance. The midgut-specific overexpression of CYP380C6, CYP6CY7, CYP6CY21, CYP4CJ1, UGT341A4, UGT344B4 and UGT344M2 significantly increased insensitivity to cyantraniliprole, and CYP380C6, CYP6CY7, CYP6CY21, UGT344B4 and UGT344M2 confer α-cypermethrin cross-resistance. The expression of CYP380C6, CYP4CJ1, UGT341A4 and UGT344M2 in broad tissues or in midgut has similar effects on insensitivity to insecticides; however, CYP6CY7, CYP6CY21 and UGT344B4 are more effective in the midgut. This result indicates that broad body tissues and midgut tissue are involved in insecticide resistance mediated by the candidate P450s and UGTs examined.


Assuntos
Inseticidas , Difosfato de Uridina , Animais , Sistema Enzimático do Citocromo P-450/genética , Drosophila melanogaster , Glicosiltransferases/genética , Resistência a Inseticidas/genética , Inseticidas/toxicidade , Pirazóis , ortoaminobenzoatos
12.
Pestic Biochem Physiol ; 176: 104861, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34119225

RESUMO

The stereoselective difference of chiral pesticide enantiomers is an important factor of risk evaluation and the subject has received wide attention. In the present work, enantioselective metabolism of chiral phenylpyrazole insecticides including fipronil, ethiprole and flufiprole in rat liver microsomes was investigated in vitro. The result showed remarkable enantioselectivity for fipronil and ethiprole with the EF values of 0.11-0.58. The metabolite fipronil-sulfone was formed with the degradation of fipronil. R-Ethiprole to S-ethiprole transformation was observed, but not S-ethiprole to R-ethiprole. No enantioselective metabolism was observed for flufiprole with the EF values of 0.49-0.51. The enzymatic assays showed that the inhibition ratio of R-fipronil and S-ethiprole was 1.5-2.1times that of the corresponding enantiomers on CYP2E1 and CYP2D2 activity, leading to the enantioselective metabolism. The result of the homology modeling and molecular docking further revealed that S-fipronil (-7.56 kcal mol-1) and R-ethiprole (-6.45 kcal mol-1) performed better binding with CYP2E1 and CYP2D2, respectively. The results provided useful data for the risk evaluation of chiral phenylpyrazole insecticides on ecological safety and human health.


Assuntos
Inseticidas , Animais , Citocromo P-450 CYP2E1 , Inseticidas/toxicidade , Fígado , Simulação de Acoplamento Molecular , Ratos , Estereoisomerismo
13.
J Agric Food Chem ; 69(26): 7324-7333, 2021 Jul 07.
Artigo em Inglês | MEDLINE | ID: mdl-34167301

RESUMO

Chlorpyrifos (CPF) is one of the most critical insecticides in the world. However, many countries are gradually banning its use due to its reported hazardous impacts on humans. This study explored the possibility of reducing the environmental risk of CPF through appropriate agricultural management practices. Results showed that the environmental risk of CPF is lower under drainage conditions because there is more mineralization and less bound residues (BRs) than under submerged conditions. Bioaugmentation significantly enhanced the CPF mineralization and inhibited the formation of CPF-BRs. Biochar adsorbed CPF and thus reduced its bioavailability, but it could not completely eliminate the toxicity of CPF. In addition, bioaugmentation did not significantly affect the native microbial community of CPF-contaminated soil, suggesting its safety in reducing the environmental risk of CPF. The study indicated that the environmental risk of CPF could be reduced by appropriate agricultural management such as water management, bioaugmentation, soil biochar amendment, and selecting suitable soil types.


Assuntos
Clorpirifos , Inseticidas , Agricultura , Radioisótopos de Carbono , Clorpirifos/toxicidade , Humanos , Inseticidas/análise , Inseticidas/toxicidade
14.
Ann Agric Environ Med ; 28(2): 358-360, 2021 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-34184524

RESUMO

INTRODUCTION: Carbamate insecticides are methyl carbamic acid esters and reversible cholinesterase inhibitors. In contrast to the long-term action of organophosphate insecticides, this complex undergoes rapid hydrolysis. CASE REPORT: A suicidal poisoning by exposure to carbofuran in a 43-year-old farmer is reported. The patient had a sudden respiratory and cardiac arrest in the mechanism of bradycardia asystole. He was additionally diagnosed with metabolic acidosis and massive aspiration pneumonia. After applied treatment, the patient's general condition improved - alignment of efficiency of both respiratory and circulatory efficiency were reached. CONCLUSION: Carbofuran is one of the most toxic carbamate insecticides. It is therefore important to react quickly and choose the right treatment. Differentiation between organophosphate and carbamate intoxication is essential.


Assuntos
Carbofurano/toxicidade , Inseticidas/toxicidade , Envenenamento/etiologia , Adulto , Fazendeiros , Humanos , Masculino , Envenenamento/psicologia , Suicídio
15.
Molecules ; 26(10)2021 May 18.
Artigo em Inglês | MEDLINE | ID: mdl-34069969

RESUMO

G-protein coupled receptors (GPCRs) play important roles in cell biology and insects' physiological processes, toxicological response and the development of insecticide resistance. New information on genome sequences, proteomic and transcriptome analysis and expression patterns of GPCRs in organs such as the central nervous system in different organisms has shown the importance of these signaling regulatory GPCRs and their impact on vital cell functions. Our growing understanding of the role played by GPCRs at the cellular, genome, transcriptome and tissue levels is now being utilized to develop new targets that will sidestep many of the problems currently hindering human disease control and insect pest management. This article reviews recent work on the expression and function of GPCRs in insects, focusing on the molecular complexes governing the insect physiology and development of insecticide resistance and examining the genome information for GPCRs in two medically important insects, mosquitoes and house flies, and their orthologs in the model insect species Drosophila melanogaster. The tissue specific distribution and expression of the insect GPCRs is discussed, along with fresh insights into practical aspects of insect physiology and toxicology that could be fundamental for efforts to develop new, more effective, strategies for pest control and resistance management.


Assuntos
Insetos/efeitos dos fármacos , Insetos/metabolismo , Inseticidas/toxicidade , Receptores Acoplados a Proteínas G/metabolismo , Animais , Regulação da Expressão Gênica/efeitos dos fármacos , Insetos/genética , Resistência a Inseticidas/genética , Especificidade de Órgãos/efeitos dos fármacos , Especificidade de Órgãos/genética
16.
Braz J Biol ; 83: e240118, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34133488

RESUMO

For many centuries human populations have been suffering and trying to fight with disease-bearing mosquitoes. Emerging and reemerging diseases such as Dengue, Zika, and Chikungunya affect billions of people around the world and recently has been appealing to control with chemical pesticides. Malathion (MT) is one of the main pesticides used against mosquitoes, the vectors of these diseases. This study aimed to assess cytotoxicity and mutagenicity of the malathion for the bioindicator Allium cepa L. using a multivariate and integrative approach. Moreover, an appendix table was compiled with all available literature of insecticides assessed by the Allium cepa system to support our discussion. Exposures during 48h to 0.5 mg mL-1 and 1.0 mg mL-1 MT were compared to the negative control (distilled water) and positive control (MMS solution at 10 mg L-1). The presence of chromosomal aberrations, micronuclei frequency, and mitotic index abnormalities was evaluated. Anaphase bridges were the alterations with higher incidence and presented a significantly elevated rate in the concentration of 0.5 mg mL-1, including when compared to the positive control. The integrative discriminant analysis summarizes that MT in assessed concentrations presented effects like the positive control, corroborating its potential of toxicity to DNA. Therefore, it is concluded that MT in its pure composition and in realistic concentrations used, has genotoxic potential in the biological assessment of A. cepa cells. The multivariate integrative analysis was fundamental to show a whole response of all data, providing a global view of the effect of MT on DNA.


Assuntos
Inseticidas , Infecção por Zika virus , Zika virus , Animais , Aberrações Cromossômicas , Dano ao DNA , Humanos , Inseticidas/toxicidade , Malation/toxicidade , Índice Mitótico , Mosquitos Vetores , Cebolas , Raízes de Plantas
17.
Sci Total Environ ; 784: 147167, 2021 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-34088063

RESUMO

This study aimed to investigate the effect of imidacloprid on structural (invertebrates and primary producers) and functional (organic matter decomposition and physicochemical parameters) characteristics of tropical freshwaters using acute single species and mesocosm studies performed in Ethiopia. The recovery of affected endpoints was also studied by using a mesocosm study period of 21 weeks. Our acute toxicity test showed that Cloeon dipterum (96-h EC50 = 1.5 µg/L) and Caenis horaria (96-h EC50 = 1.9 µg/L) are relatively sensitive arthropods to imidacloprid. The mesocosm experiment evaluated the effects of four applications of imidacloprid with a weekly interval and the results showed that the macroinvertebrate and zooplankton community structure changed significantly due to imidacloprid contamination in mesocosms repeatedly dosed with ≥0.1 and ≥ 0.01 µg/L, respectively (time weighted average concentrations of 112 days (TWA112d) of ≥0.124 and ≥ ≈0.02 µg/L, respectively). The largest responses were found for C. dipterum, C. horaria, Brachionus sp. and Filinia sp. Chlorophyll-a concentrations of periphyton and phytoplankton significantly increased in the ≥0.1 µg/L treatments levels which are indirect effects as a result of the release of grazing pressure. A significant, but quantitatively small, decrease of organic matter decomposition rate was observed in mesocosms treated with repeated doses of 1 µg/L (TWA112d of 2.09 µg/L). No recovery was observed for the macroinvertebrates community during the study period of 21 weeks, but zooplankton recovered after 9 weeks. We observed spatio-temporal related toxicity differences between tropical and temperate aquatic taxa, with tropical taxa generally being more sensitive. This suggests that use of temperate toxicity data for the risk assessment of imidacloprid in tropical region is not recommended.


Assuntos
Inseticidas , Poluentes Químicos da Água , Animais , Ecossistema , Etiópia , Água Doce , Inseticidas/análise , Inseticidas/toxicidade , Neonicotinoides , Nitrocompostos , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/toxicidade
18.
Int J Mol Sci ; 22(10)2021 May 12.
Artigo em Inglês | MEDLINE | ID: mdl-34065933

RESUMO

Neonicotinoid insecticides are nicotine-derived molecules which exert acute neurotoxic effects over the insect central nervous system by activating nicotinic acetylcholine receptors (nAChRs). However, these receptors are also present in the mammalian central and peripheral nervous system, where the effects of neonicotinoids are faintly known. In mammals, cholinergic synapses are crucial for the control of vascular tone, blood pressure and skeletal muscle contraction. We therefore hypothesized that neonicotinoids could affect cholinergic networks in mammals and sought to highlight functional consequences of acute intoxication in rats with sub-lethal concentrations of the highly used acetamiprid (ACE) and clothianidin (CLO). In this view, we characterized their electrophysiological effects on rat α3ß4 nAChRs, knowing that it is predominantly expressed in ganglia of the vegetative nervous system and the adrenal medulla, which initiates catecholamine secretion. Both molecules exhibited a weak agonist effect on α3ß4 receptors. Accordingly, their influence on epinephrine secretion from rat adrenal glands was also weak at 100 µM, but it was stronger at 500 µM. Challenging ACE or CLO together with nicotine (NIC) ended up with paradoxical effects on secretion. In addition, we measured the rat arterial blood pressure (ABP) in vivo by arterial catheterization. As expected, NIC induced a significant increase in ABP. ACE and CLO did not affect the ABP in the same conditions. However, simultaneous exposure of rats to both NIC and ACE/CLO promoted an increase of ABP and induced a biphasic response. Modeling the interaction of ACE or CLO on α3ß4 nAChR is consistent with a binding site located in the agonist pocket of the receptor. We present a transversal experimental approach of mammal intoxication with neonicotinoids at different scales, including in vitro, ex vivo, in vivo and in silico. It paves the way of the acute and chronic toxicity for this class of insecticides on mammalian organisms.


Assuntos
Epinefrina/metabolismo , Inseticidas/toxicidade , Neonicotinoides/toxicidade , Nicotina/toxicidade , Receptores Nicotínicos/metabolismo , Medula Suprarrenal/efeitos dos fármacos , Medula Suprarrenal/metabolismo , Animais , Pressão Arterial/efeitos dos fármacos , Modelos Animais de Doenças , Agonismo Parcial de Drogas , Gânglios/efeitos dos fármacos , Gânglios/metabolismo , Regulação da Expressão Gênica/efeitos dos fármacos , Guanidinas/toxicidade , Masculino , Ratos , Tiazóis/toxicidade , Testes de Toxicidade Subaguda
19.
Environ Monit Assess ; 193(7): 382, 2021 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-34089115

RESUMO

Oxycarenus hyalinipennis Costa is a polyphagous insect pest and can develop insecticide resistance. The resistance of O. hyalinipennis to neonicotinoids (clothianidin and dinotefuran), flonicamid, and conventional insecticides; carbamates (methomyl and carbosulfon), organophosphates (chlorpyrifos and malathion), and pyrethroids (cypermethrin and zeta-cypermethrin) was evaluated. The O. hyalinipennis populations were sampled from four locations in Pakistan and performed bioassays against the insecticides by leaf dip protocol. The O. hyalinipennis' populations showed low resistance to carbosulfan (resistance ratio (RR) = 2.06-6.34) and methomyl (RR = 2.78-7.27), moderate to high resistance to chlorpyrifos (RR = 30-45), malathion (RR = 20.29-88.19), and flonicamid (RR = 14.24-46.97), in comparison with the susceptible strain. Susceptibility to low resistance against cypermethrin (RR = 1.27-2.82), zeta-cypermethrin (RR = 2.62-3.38), and clothianidin (RR = 1.74-3.40), and low to moderate resistance to dinotefuran (RR = 3.84-13.43) in the field populations, was observed compared to the susceptible strain. A rotational usage of carbamates and pyrethroids with an integrated pest management tool should be considered to deal with O. hyalinipennis' insecticide resistance.


Assuntos
Inseticidas , Monitoramento Ambiental , Inseticidas/toxicidade , Neonicotinoides , Niacinamida/análogos & derivados , Paquistão
20.
Toxins (Basel) ; 13(5)2021 05 16.
Artigo em Inglês | MEDLINE | ID: mdl-34065665

RESUMO

Bacillus thuringiensis (Bt), a natural pathogen of different invertebrates, primarily insects, is widely used as a biological control agent. While Bt-based preparations are claimed to be safe for non-target organisms due to the immense host specificity of the bacterium, the growing evidence witnesses the distant consequences of their application for natural communities. For instance, upon introduction to soil habitats, Bt strains can affect indigenous microorganisms, such as bacteria and fungi, and further establish complex relationships with local plants, ranging from a mostly beneficial demeanor, to pathogenesis-like plant colonization. By exerting a direct effect on target insects, Bt can indirectly affect other organisms in the food chain. Furthermore, they can also exert an off-target activity on various soil and terrestrial invertebrates, and the frequent acquisition of virulence factors unrelated to major insecticidal toxins can extend the Bt host range to vertebrates, including humans. Even in the absence of direct detrimental effects, the exposure to Bt treatment may affect non-target organisms by reducing prey base and its nutritional value, resulting in delayed alleviation of their viability. The immense phenotypic plasticity of Bt strains, coupled with the complexity of ecological relationships they can engage in, indicates that further assessment of future Bt-based pesticides' safety should consider multiple levels of ecosystem organization and extend to a wide variety of their inhabitants.


Assuntos
Toxinas de Bacillus thuringiensis/administração & dosagem , Bacillus thuringiensis/patogenicidade , Agentes de Controle Biológico/administração & dosagem , Animais , Toxinas de Bacillus thuringiensis/toxicidade , Agentes de Controle Biológico/toxicidade , Ecossistema , Humanos , Inseticidas/administração & dosagem , Inseticidas/toxicidade , Controle Biológico de Vetores/métodos , Fenótipo
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