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1.
Chemosphere ; 282: 131120, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34470165

RESUMO

This study evaluated the adverse effects of low-dose imidacloprid (IMI) on the characteristics of sperm from male Wistar rats. Thirty mature male rats were equally divided into three groups and orally administered vehicle (Control Group), acceptable daily intake (ADI) concentration of IMI (Group 1), and IMI at a dose 10-fold that of the ADI (Group 2) for 90 days. The findings revealed that IMI caused abnormalities in sperm concentrations and morphologies, accompanied by an imbalance of the gonadal hormone testosterone. Histopathological damage and decrease of testosterone levels were observed in testes from rats treated with IMI. However, estradiol and gonadotropin levels were unchanged after IMI treatment. IMI inhibited the activity of cytochrome P450 3A4 (CYP3A4) and left itself existed in the organism of rats. The indicators relating to sperms and CYP3A4 activity were recovered when rats were co-treated with IMI and CYP3A4 inducer rifampicin together. These results indicated that low-dose IMI exposure caused sperm abnormalities through affecting on the spermiogenesis in testis. Inhibition of CYP3A4 activity by IMI largely contributed to its sperm toxicity. Thus, IMI exposure at doses close to real-world settings resulted in sperm toxicity on rats, which might be a potential risk factor for human reproductive diseases.


Assuntos
Citocromo P-450 CYP3A , Espermatogênese , Animais , Masculino , Neonicotinoides/toxicidade , Nitrocompostos , Ratos , Ratos Wistar , Espermatozoides , Testículo , Testosterona
2.
J Hazard Mater ; 416: 125861, 2021 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-34492809

RESUMO

Neonicotinoid insecticides have been widely used due to their excellent systemic activity and high insecticidal activity, but the problems of low utilization rate and environmental risk have attracted widespread attention. Controlled-release technology is an approach to realize the efficient utilization of pesticides and reduce environmental pressure. In this study, clothianidin (CLO) controlled-release granules (CLO@GR- TA (tannic acid)/Fe (III)) were prepared with TA/Fe (III) coordination chelate as the coating material. These granules exhibited the core-shell structure with 500-1200 µm of particle size, and had obvious release performance and hydrolysis behavior of coating materials. Pot experiments by root application showed that the CLO@GR-TA/Fe (III) showed balanced and lasting control efficacy to broad bean aphids. The plants have a stronger capacity for absorption and enrichment and a higher utilization rate of CLO for CLO@GR-TA/Fe (III), than those for 10% suspension concentrate (SC). One of the hydrolysates of coating materials, TA, a polyphenolic antioxidant, could improve the bioaccumulation amount and alleviating the oxidative stress response of CLO in plants. Our study illustrates that the controlled-release granules base on TA have efficient controlled-release properties and free radical scavenging performance that may eventually be used as pesticide carriers and antioxidants in the field of plant protection.


Assuntos
Praguicidas , Disponibilidade Biológica , Preparações de Ação Retardada , Guanidinas , Neonicotinoides/toxicidade , Estresse Oxidativo , Praguicidas/toxicidade , Tiazóis
3.
Ecotoxicol Environ Saf ; 223: 112563, 2021 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-34343900

RESUMO

Although many toxicological evaluations have been conducted for honey bees (Apis mellifera), most of these studies have only focused on the effects of individual chemicals. However, honey bees are usually exposed to pesticide mixtures under field conditions. In this study, we examined the effects of individual pesticides and mixtures of clothianidin (CLO) with eight other pesticides [carbaryl (CAR), thiodicarb (THI), chlorpyrifos (CHL), beta-cyfluthrin (BCY), gamma-cyhalothrin (GCY), tetraconazole (TET), spinosad (SPI) and indoxacarb (IND)] on honey bees using a feeding method. Toxicity tests of a 4-day exposure to individual pesticides revealed that CLO had the highest toxicity to A. mellifera, with an LC50 value of 0.24 µg a.i. mL-1, followed by IND and CHL with LC50 values of 3.40 and 3.56 µg a.i. mL-1, respectively. SPI and CAR had relatively low toxicities, with LC50 values of 7.19 and 8.42 µg a.i. mL-1, respectively. In contrast, TET exhibited the least toxicity, with an LC50 value of 258.7 µg a.i. mL-1. Most binary mixtures of CLO with other pesticides exerted additive and antagonistic effects. However, all the ternary mixtures containing CLO and TET (except for CLO+TET+THD) elicited synergistic responses to bees. Either increased numbers of components in the mixture or/and a unique mode of action appeared to be responsible for the higher toxicity of mixtures. Our findings emphasized the need for risk assessment of pesticide mixtures rather than the individual chemicals. Our data also provided information that might help growers avoid increased toxicity and unnecessary injury to pollinators.


Assuntos
Inseticidas , Praguicidas , Animais , Abelhas , Guanidinas/toxicidade , Inseticidas/toxicidade , Neonicotinoides/toxicidade , Praguicidas/toxicidade , Tiazóis
4.
Ecotoxicol Environ Saf ; 223: 112581, 2021 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-34352576

RESUMO

The increasing use of insecticides, promoted by the intensification of agriculture, has raised concerns about their influence on the decline of bee colonies, which play a fundamental role in pollination. Thus, it is fundamental to elucidate the effects of insecticides on bees. This study investigated the damage caused by a sublethal concentration of thiamethoxam - TMX (0.0227 ng/µL of feed) in the head and midgut of Africanized Apis mellifera, by analyzing the enzymatic biomarkers, oxidative stress, and occurrence of lipid peroxidation. The data showed that the insecticide increased acetylcholinesterase activity (AChE) and glutathione-S-transferase (GST), whereas carboxylesterase (CaE3) activity decreased in the heads. Our results indicate that the antioxidant enzymes were less active in the head because only glutathione peroxidase (GPX) showed alterations. In the midgut, there were no alkaline phosphatase (ALP) or superoxide dismutase (SOD) responses and a decrease in the activity of CaE was observed. Otherwise, there was an increase in GPX, and the TBARS (thiobarbituric acid reactive substances) assay also showed differences in the midgut. The TBARS (thiobarbituric acid reactive substances) assay also showed differences in the midgut. The results showed enzymes such as CaE3, GST, AChE, ALP, SOD, and GPX, as well as the TBARS assay, are useful biomarkers on bees. They may be used in combination as a promising tool for characterizing bee exposure to insecticides.


Assuntos
Inseticidas , Nitrocompostos , Animais , Abelhas , Inseticidas/toxicidade , Neonicotinoides/toxicidade , Nitrocompostos/toxicidade , Oxazinas/toxicidade , Tiametoxam , Tiazóis/toxicidade
5.
Artigo em Inglês | MEDLINE | ID: mdl-34360075

RESUMO

Nanoparticles have applications in various fields such as manufacturing and materials synthesis, the environment, electronics, energy harvesting, and medicine. Besides many applications of nanoparticles, further research is required for toxic environmental effect investigation. The toxic effect of titanium dioxide nanoparticles on the physiology of the green alga Chlorella vulgaris was studied with a widely used pesticide, imidacloprid (IMD). Chlorella vulgaris was exposed for 120 h in Bold's basal medium to different toxic compounds, such as (i) a high concentration of TiO2 nanoparticles, 150-2000 mg/L, usually optimised in the photocatalytic degradation of wastewater, (ii) an extremely toxic pesticide for the aquatic environment, imidacloprid, in concentrations ranging from 5 to 40 mg/L, (iii) TiO2 nanoparticles combined with imidacloprid, usually used in a photocatalytic system. The results show that the TiO2 nanoparticles and IMD inhibited Chlorella vulgaris cell growth and decreased the biovolume by approximately 80% when 2 g/L TiO2 was used, meaning that the cells devised a mechanism to cope with a potentially stressful situation; 120 h of Chlorella vulgaris exposure to 40 mg/L of IMD resulted in a 16% decreased cell diameter and a 41% decrease in cell volume relative to the control sample, associated with the toxic effect of pesticides on the cells. Our study confirms the toxicity of nanoparticles through algal growth inhibition with an effective concentration (EC50) value measured after 72 h of 388.14 mg/L for TiO2 and 13 mg/L for IMD in a single-toxic system. The EC50 of TiO2 slowly decreased from 258.42 to 311.11 mg/L when IMD from 5 to 20 mg/L was added to the binary-toxic system. The concentration of TiO2 in the binary-toxic system did not change the EC50 for IMD, and its value was 0.019 g/L. The photodegradation process of imidacloprid (range of 5-40 mg/L) was also investigated in the algal medium incubated with 150-600 mg/L of titanium dioxide.


Assuntos
Chlorella vulgaris , Poluentes Químicos da Água , Neonicotinoides/toxicidade , Nitrocompostos , Titânio/toxicidade
6.
Pestic Biochem Physiol ; 178: 104924, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34446200

RESUMO

The sulfoximines, as exemplified by sulfoxaflor (Isoclast™active), are a relatively new class of nicotinic acetylcholine receptor (nAChR) competitive modulator (Insecticide Resistance Action Committee [IRAC] Group 4C) insecticides that provide control of a wide range of sap-feeding insect pests. The sulfoximine chemistry and sulfoxaflor exhibits distinct interactions with metabolic enzymes and nAChRs compared to other IRAC Group 4 insecticides such as the neonicotinoids (Group 4A). These distinctions translate to notable differences in the frequency and degree of cross-resistance between sulfoxaflor and other insecticides. Most insect strains exhibiting resistance to a variety of insecticides, including neonicotinoids, exhibited little to no cross-resistance to sulfoxaflor. To date, only two laboratory-based studies involving four strains (Koo et al. 2014, Chen et al. 2017) have observed substantial cross-resistance (>100 fold) to sulfoxaflor in neonicotinoid resistant insects. Where higher levels of cross-resistance to sulfoxaflor are observed the magnitude of that resistance is far less than that of the selecting neonicotinoid. Importantly, there is no correlation between presence of resistance to neonicotinoids (i.e., imidacloprid, acetamiprid) and cross-resistance to sulfoxaflor. This phenomenon is consistent with and can be attributed to the unique and differentiated chemical class represented by sulfoxalfor. Recent studies have demonstrated that high levels of resistance (resistance ratio = 124-366) to sulfoxaflor can be selected for in the laboratory which thus far appear to be associated with enhanced metabolism by specific cytochrome P450s, although other resistance mechanisms have not yet been excluded. One hypothesis is that sulfoxaflor selects for and is susceptible to a subset of P450s with different substrate specificity. A range of chemoinformatic, molecular modeling, metabolism and target-site studies have been published. These studies point to distinctions in the chemistry of sulfoxaflor, and its metabolism by enzymes associated with resistance to other insecticides, as well as its interaction with insect nicotinic acetylcholine receptors, further supporting the subgrouping of sulfoxaflor (Group 4C) separate from that of other Group 4 insecticides. Herein is an expansion of an earlier review (Sparks et al. 2013), providing an update that considers prior and current studies focused on the mode of action of sulfoxaflor, along with an analysis of the presently available resistance / cross-resistance studies, and implications and recommendations regarding resistance management.


Assuntos
Inseticidas , Receptores Nicotínicos , Resistência a Inseticidas , Inseticidas/toxicidade , Neonicotinoides/toxicidade , Nitrocompostos/toxicidade , Piridinas/toxicidade , Compostos de Enxofre
7.
Int J Mol Sci ; 22(16)2021 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-34445117

RESUMO

Neonicotinoids are a class of insecticides that exert their effect through a specific action on neuronal nicotinic acetylcholine receptors (nAChRs). The success of these insecticides is due to this mechanism of action, since they act as potent agonists of insect nAChRs, presenting low affinity for vertebrate nAChRs, which reduces potential toxic risk and increases safety for non-target species. However, although neonicotinoids are considered safe, their presence in the environment could increase the risk of exposure and toxicity. On the other hand, although neonicotinoids have low affinity for mammalian nAChRs, the large quantity, variety, and ubiquity of these receptors, combined with its diversity of functions, raises the question of what effects these insecticides can produce in non-target species. In the present systematic review, we investigate the available evidence on the biochemical and behavioral effects of neonicotinoids on the mammalian nervous system. In general, exposure to neonicotinoids at an early age alters the correct neuronal development, with decreases in neurogenesis and alterations in migration, and induces neuroinflammation. In adulthood, neonicotinoids induce neurobehavioral toxicity, these effects being associated with their modulating action on nAChRs, with consequent neurochemical alterations. These alterations include decreased expression of nAChRs, modifications in acetylcholinesterase activity, and significant changes in the function of the nigrostriatal dopaminergic system. All these effects can lead to the activation of a series of intracellular signaling pathways that generate oxidative stress, neuroinflammation and, finally, neuronal death. Neonicotinoid-induced changes in nAChR function could be responsible for most of the effects observed in the different studies.


Assuntos
Mamíferos/metabolismo , Neonicotinoides/toxicidade , Receptores Nicotínicos/metabolismo , Animais , Humanos , Inseticidas/toxicidade , Neurônios/efeitos dos fármacos , Neurônios/metabolismo
8.
Environ Pollut ; 289: 117866, 2021 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-34343750

RESUMO

The neonicotinoid insecticide acetamiprid is widely applied for pest control in agriculture production, and its exposure often results in adverse effects on a non-target insect, Bombyx mori. However, only few studies have investigated the effects of exposure to sublethal doses of neonicotinoid insecticides on gut microbiota and susceptibility to pathogenic bacteria. In this study, we aimed to explore the possible mechanisms underlying the acetamiprid-induced compositional changes in gut microbiota of silkworm and reduced host resistance against detrimental microbes. This study indicated that sublethal dose of acetamiprid activated the dual oxidase-reactive oxygen species (Duox-ROS) system and induced ROS accumulation, leading to dysregulation of intestinal immune signaling pathways. The evenness and structure of bacterial community were altered. Moreover, after 96 h of exposure to sublethal dose of acetamiprid, several bacteria, such as Pseudomonas sp (Biotype A, DOP-1a, XW34) and Staphylococcus sp (RCB1054, RCB314, X302), invaded the silkworm hemolymph. The survival rate and bodyweight of the acetamiprid treated silkworm larvae inoculated with Enterobacter cloacae (E. cloacae) were significantly lower than the acetamiprid treatment group, suggesting that acetamiprid reduced silkworm resistance against pathogens. These findings indicated that acetamiprid disturbed gut microbial homeostasis of Bombyx mori, resulting in changes in gut microbial community and susceptibility to detrimental microbes.


Assuntos
Bombyx , Animais , Bactérias , Homeostase , Neonicotinoides/toxicidade
9.
Environ Toxicol Pharmacol ; 87: 103724, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34416397

RESUMO

The testicular deficiency associated with exposure to three widely used insecticides in Egyptian agriculture was evaluated. Animals were orally treated with sub-lethal dose (1/50 of the oral LD50) of cypermethrin (CYP), imidacloprid (IMC), and chlorpyrifos (CPF) at 5, 9 and 1.9 mg/kg/day, respectively, five times a week for one month. The CYP, IMC, and CPF exposure resulted in a significant decline in animal body weight, sperm count, motility, normality, and viability with increased head and tail deformities. Significant reduction in serum testosterone, luteinizing hormone (LH), follicle-stimulating hormone (FSH), testis superoxide dismutase (SOD), and reduced glutathione (GSH) levels. In contrast, catalase (CAT), lipid peroxidation (LPO), and protein carbonyl content (PCC) levels were significantly stimulated. Jointly, obtained results were confirmed by microscopic examination of testis sections. The present data concluded that the CYP, IMC, and CPF have a public health impact and violently interferes with male rat reproductive system.


Assuntos
Clorpirifos/toxicidade , Inseticidas/toxicidade , Neonicotinoides/toxicidade , Nitrocompostos/toxicidade , Piretrinas/toxicidade , Testículo/efeitos dos fármacos , Animais , Catalase/metabolismo , Hormônio Foliculoestimulante/sangue , Glutationa/metabolismo , Peroxidação de Lipídeos/efeitos dos fármacos , Hormônio Luteinizante/sangue , Masculino , Carbonilação Proteica/efeitos dos fármacos , Ratos , Espermatozoides/anormalidades , Espermatozoides/efeitos dos fármacos , Superóxido Dismutase/metabolismo , Testículo/metabolismo , Testículo/patologia , Testosterona/sangue
10.
Environ Pollut ; 289: 117892, 2021 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-34385134

RESUMO

Thiacloprid is a neonicotinoid insecticide widely exploited in agriculture and easily mobilized towards aquatic environments by atmospheric agents. However, little information about its toxicological effects on aquatic invertebrate bioindicators is available. In this study, specimens of the mussel Mytilus galloprovincialis were exposed to thiacloprid at environmental (4.5 µg L-1) and 100 times higher than environmental (450 µg L-1) concentrations for 20 days. Thiacloprid affected haemolymph biochemical parameters, cell viability in the digestive gland, antioxidant biomarkers and lipid peroxidation in the digestive gland and gills at environmentally relevant concentrations (4.5 µg L-1). In addition, thiacloprid exposure caused histological damage to the digestive gland and gills. Interestingly, the pesticide was detected at levels equal to 0.14 ng g-1 in the soft tissues of sentinels exposed for 20 days to 450 µg L-1 thiacloprid in seawaterµ. Due to its harmful potential and cumulative effects after long-term exposure of M. galloprovincialis, thiacloprid may pose a potential risk to nontarget aquatic organisms, as well as to human health. This aspect requires further in-depth investigation.


Assuntos
Mytilus , Tiazinas , Poluentes Químicos da Água , Animais , Biomarcadores , Brânquias , Humanos , Neonicotinoides/toxicidade , Tiazinas/toxicidade , Poluentes Químicos da Água/toxicidade
11.
Ecotoxicol Environ Saf ; 222: 112476, 2021 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-34214772

RESUMO

The neonicotinoid pesticide, imidacloprid (IMI), is frequently detected in the environment and in foods. It is absorbed and metabolized by the intestine; however, its effects on intestinal barrier integrity are not well studied. We investigated whether IMI disrupts the permeability of the intestinal epithelial barrier via in vivo tests on male Wistar rats, in vitro assays using the human intestinal epithelial cell line, Caco-2, and in silico analyses. A repeated oral dose 90-day toxicity study was performed (0.06 mg/kg body weight/day). IMI exposure significantly increased intestinal permeability, which led to significantly elevated serum levels of endotoxin and inflammatory biomarkers (tumor necrosis factor-alpha and interleukin-1 beta) without any variation in body weight. Decreased transepithelial electrical resistance with increased permeability was also observed in 100 nM and 100 µM IMI-treated Caco-2 cell monolayers. Amounts of tight junction proteins in IMI-treated colon tissues and between IMI-treated Caco-2 cells were significantly lower than those of controls. Increased levels of myosin light chain phosphorylation, myosin light chain kinase (MLCK), and p65 subunit of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB p65) phosphorylation were found in IMI-exposed cells compared with control cells. Furthermore, the barrier loss caused by IMI was rescued by the MLCK inhibitor, ML-7, and cycloheximide. Pregnane X receptor (PXR, NR1I2) was inhibited by low-dose IMI treatment. In silico analysis indicated potent binding sites between PXR and IMI. Together, these data illustrate that IMI induces intestinal epithelial barrier disruption and produces an inflammatory response, involving the down-regulation of tight junctions and disturbance of the PXR-NF-κB p65-MLCK signaling pathway. The intestinal barrier disruption caused by IMI deserves attention in assessing the safety of this neonicotinoid pesticide.


Assuntos
Mucosa Intestinal , Junções Íntimas , Animais , Células CACO-2 , Humanos , Intestinos , Masculino , Neonicotinoides/toxicidade , Nitrocompostos , Permeabilidade , Ratos , Ratos Wistar , Fator de Necrose Tumoral alfa
12.
Sci Total Environ ; 795: 148680, 2021 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-34247092

RESUMO

A range of anthropogenic factors are causing unprecedented bee declines. Among these drivers the usage of pesticides is believed to be crucial. While the use of key bee-harming insecticides, such as the neonicotinoids, has been reduced by regulatory authorities, novel, less studied substances have occupied their market niche. Understanding the threat of these chemicals to bees is, therefore, crucial to their conservation. Here we focus on sulfoxaflor, a novel insecticide, targeting the same neural receptor as the neonicotinoids. In stark contrast to the growing concerns around its negative impacts on bee health, a recent assessment has resulted in the extension of its authorisations across the USA. However, such assessments may underestimate risks by overlooking interactive impacts of multiple stressors. Here we investigated co-occurring, lethal and sublethal risks of sulfoxaflor and a dietary stress for bumblebees (Bombus terrestris), a key pollinator. Specifically, we employed a novel microcolony design, where, for the first time in bees, pesticide exposure mimicked natural degradation. We orally exposed workers to sulfoxaflor and a sugar-deficient diet in a fully factorial design. Field realistic, worst-case sulfoxaflor exposure caused a sharp increase in bee mortality. At sublethal concentrations, sulfoxaflor negatively affected bee fecundity, but not survival. Nutritional stress reduced bee fecundity and synergistically or additively aggravated impacts of sulfoxaflor on bee survival, egg laying and larval production. Our data show that non-mitigated label uses of sulfoxaflor may have major, yet severely neglected effects on bumblebee health, which may be exacerbated by nutritional stress. By unravelling mechanistic interactions of synergistic risks, our study highlights the need to overcome inherent limitations of Environmental Risk Assessment schemes, which, being based on a "single stressor paradigm", may fail to inform policymakers of the real risks of pesticide use.


Assuntos
Inseticidas , Desnutrição , Animais , Abelhas , Fertilidade , Inseticidas/toxicidade , Neonicotinoides/toxicidade , Piridinas , Compostos de Enxofre
13.
Pestic Biochem Physiol ; 177: 104885, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34301353

RESUMO

Imidacloprid is a neonicotinoid that targets sucking pests, such as aphids and the green leaf bug and has been widely applied in wheat fields to control wheat aphids in China. To investigate the involvement of miRNAs in imidacloprid resistance, we sequenced small RNA libraries of Sitobion miscanthi Fabricius, across two different treatments using Illumina short-read sequencing technology. As a result, 265 microRNAs (miRNAs), of which 242 were known and 23 were novel, were identified. Quantitative analysis of miRNA levels showed that 23 miRNAs were significantly up-regulated, and 54 miRNAs were significantly down-regulated in the nymphs of S. miscanthi treated with imidacloprid in comparison with those of the control. Modulation of the abundances of differentially expressed miRNAs, smi-miR-316, smi-miR-1000, and smi-miR-iab-4 by the addition of the corresponding antagomir/inhibitor to the artificial diet significantly changed the susceptibility of S. miscanthi to imidacloprid. Subsequently, the post-transcriptional regulatory mechanism was conducted, smi-miR-278 and smi-miR-316 were confirmed to be participated in the post-transcriptional regulation of nAChRα1A and CYP4CJ6, respectively. The results suggested that miRNAs differentially expressed in response to imidacloprid could play a critical regulatory role in the metabolism of S. miscanthi to imidacloprid.


Assuntos
Afídeos , MicroRNAs , Animais , Afídeos/genética , China , Perfilação da Expressão Gênica , MicroRNAs/genética , Neonicotinoides/toxicidade , Nitrocompostos
14.
J Hazard Mater ; 418: 126391, 2021 09 15.
Artigo em Inglês | MEDLINE | ID: mdl-34329022

RESUMO

Rare studies investigated influence of neonicotinoid insecticides on the whole soil biota including non-target invertebrates and microorganisms. And less is known about the consequent intervention on soil C processes. This study aimed to decipher Collembola-fungi-bacteria interactive effects on pathways of maize C translocation, combining isotopic tracer analysis of relevant compartments with high-throughput sequencing for bacterial and fungal genetic profiles. Dinotefuran was applied at 0 or 100 µg kg-1 (a simulating residual dosage) to microcosms containing soils, Collembola and 13C labelled maize. Dinotefuran drastically reduced the density and maize-derived biomass C of Collembola, while intensifying antagonistic associations between soil organisms, with flourishing growth of Ascomycota and Actinobacteria, e.g., Streptomyces. This led to higher soil organic C (SOC) mineralization (elevated by 9.8-10.5%) across soils, attributing to the shift in microbial taxonomic and functional guild, e.g., with the increased abundance of genes aligned to cytochrome P450. Maize decomposition was controlled by Collembola that primarily fed on maize, via grazing behavior that facilitated labile maize C preferred decomposers, e.g., Xanthomonadaceae. These findings elucidate the influence of minute dinotefuran on intra-linkages between biomes (Collembola, fungi and bacteria), and highlight such legacy effects on maize and SOC mineralization.


Assuntos
Carbono , Solo , Bactérias/genética , Fungos , Guanidinas , Neonicotinoides/toxicidade , Nitrocompostos , Microbiologia do Solo , Zea mays
15.
Environ Pollut ; 289: 117813, 2021 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-34332171

RESUMO

Seed coating ('seed treatment') is the leading delivery method of neonicotinoid insecticides in major crops such as soybean, wheat, cotton and maize. However, this prophylactic use of neonicotinoids is widely discussed from the standpoint of environmental costs. Growing soybean plants from neonicotinoid-coated seeds in field, we demonstrate that soybean aphids (Aphis glycines) survived the treatment, and excreted honeydew containing neonicotinoids. Biochemical analyses demonstrated that honeydew excreted by the soybean aphid contained substantial concentrations of neonicotinoids even one month after sowing of the crop. Consuming this honeydew reduced the longevity of two biological control agents of the soybean aphid, the predatory midge Aphidoletes aphidimyza and the parasitic wasp Aphelinus certus. These results have important environmental and economic implications because honeydew is the main carbohydrate source for many beneficial insects in agricultural landscapes.


Assuntos
Afídeos , Inseticidas , Animais , Agentes de Controle Biológico , Inseticidas/toxicidade , Neonicotinoides/toxicidade , Nitrocompostos , Oxazinas , Sementes , Soja , Tiametoxam , Tiazóis
16.
Pest Manag Sci ; 77(11): 5246-5254, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34310012

RESUMO

BACKGROUND: Neonicotinoids comprise one of the most extensively used classes of pesticides worldwide owing to their broad insecticidal spectrum and excellent biological performance. However, their toxicity to honeybee (Apis mellifera Linnaeus) and silkworm (Bombyx Mori) limits their further application. To address this issue, clothianidin as a model neonicotinoid was developed into a novel controlled-release formulation employing advantaged solid dispersion (SD) technology using composite carriers. RESULTS: In this research, the clothianidin-loaded SD was characterized using integrated methods to elucidate its formation mechanism, showing that clothianidin was embedded into the carrier homogeneously in small crystalline entities. The composite carriers, which are both renewable and environmentally friendly, can significantly prolong the release of clothianidin from seven to 25 days, compared with that of PEG 8000 as a single carrier. Based on the excellent controlled release profiles, it reduced the acute toxicity to A. mellifera and B. mori by 57.68- and 85.32-fold (respectively) compared with that of the conventional formulation. Furthermore, the SD displayed favorable efficacy and persistency against Asian citrus psyllid (Hemiptera: Psyllidae). CONCLUSION: This novel strategy opens up a simple and powerful avenue for improving efficacy and promoting the environmental safety of neonicotinoid insecticides to be used in sustainable crop protection.


Assuntos
Hemípteros , Animais , Abelhas , Guanidinas/toxicidade , Neonicotinoides/toxicidade , Tiazóis/toxicidade
17.
Chemosphere ; 284: 131327, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34216921

RESUMO

The neonicotinoids are globally used insecticides, which have been shown to cause negative impacts on birds. The current study aimed to evaluate the distribution of the neonicotinoid imidacloprid (IMI) in the tissues of a songbird and identify related physiological effects. Adults of the grayish baywing (Agelaioides baduis) were administered with a single dose of 35 mg IMI/kg, and the IMI concentration was evaluated in liver, kidney and plasma at 4, 12, 24, and 48 h after dosing. At the same time points, effects on hematological, genetic and enzymatic parameters were assessed. Results showed that IMI was absorbed before 4 h, and eliminated at 48 h, in every tissue, and the highest concentrations were detected in plasma. Baywings showed intoxication signs and reduced mobility within the first 5 min post-dosing. Hematological parameters: red blood cells, packed cell volume, hemoglobin, and their derived indices exhibited a transient elevation 24 h after dosing, which coincided with maximum concentrations of IMI in the tissues. No effects were observed on the genotoxicity parameters evaluated: micronuclei and comet assay. Treated birds exhibited an alteration of cholinesterases activity in the muscle and plasma, and of glutathione-S-transferase (GST) activity in the plasma, brain, liver, and muscle. Based on the results obtained, the combined detection of IMI and inhibition of GST activity in the plasma is suggested as a non-lethal biomarker of IMI exposure in wild birds. As efficient field monitoring depends on the availability of proven biomarkers, the current study provides valuable tools for bird conservation in agroecosystems.


Assuntos
Inseticidas , Nitrocompostos , Animais , Inseticidas/análise , Inseticidas/toxicidade , Neonicotinoides/toxicidade , Nitrocompostos/toxicidade , América do Sul , Distribuição Tecidual
18.
Chemosphere ; 283: 131177, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34146881

RESUMO

Environmentally persistent xenobiotics, such as neonicotinoid insecticides, are thought to contribute to insect declines. Much of what is known about the non-target effects on bees comes from oral exposure in eusocial species. However, most bee species are solitary and nest below ground. For them, contaminated nesting resources may represent an important, yet understudied, route of exposure. We examined the effect of chronic contact exposure with realistic soil concentrations of the neonicotinoid imidacloprid (0, 7.5, 15, or 100 ppb) during immature development on adult locomotion (movement speed and distance) and brain development of the solitary bees Osmia lignaria and Megachile rotundata. Adult locomotion and mushroom body morphology were characterized 2 (females) or 4 (males) and 14 (both sexes) days after emergence. Unlike the 0 and 7.5 ppb groups, female O. lignaria treated with 15 and 100 ppb did not move faster with age. If movement speed is associated with foraging or nest-building ability, this could result in a 25% reduction in nest provisioning efficiency over the first 14 days. Young male M. rotundata moved more quickly (7.5 and 100 ppb) and farther (100 ppb) when treated with imidacloprid, potentially increasing their ability to compete for more receptive female bees. We did not detect an effect of imidacloprid on the relative volumes of the neuropil and Kenyon cell subregions. We discuss how an environmentally persistent xenobiotic has the potential to alter population dynamics through changes in adult locomotion, even in the absence of a detectable effect on gross brain morphology.


Assuntos
Inseticidas , Nitrocompostos , Animais , Abelhas , Feminino , Inseticidas/toxicidade , Masculino , Neonicotinoides/toxicidade , Nitrocompostos/toxicidade , Solo
19.
Ecotoxicol Environ Saf ; 221: 112435, 2021 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-34171690

RESUMO

The present work was designed to assess the potential ameliorative effect of thymol on the testicular toxicity caused by imidacloprid (IMI) in adult male rats. Forty adult male rats were allocated into four groups; control group was given corn oil, thymol-treated group (30 mg/kg b.wt), IMI-treated group (22.5 mg/kg b.wt), and IMI + thymol-treated group. All administrations were done by gavage every day for duration of 56 days. As a result, the IMI exposure caused a significant decline in the body weight change, reproductive organ weights, sperm functional parameters, and serum level of testosterone, widespread histological alterations, and apoptosis in the testis. Additionally, the IMI-treated rats exhibited a remarkable increment in the serum levels of follicle stimulating hormone and luteinizing hormone. Also, IMI induced testicular oxidative stress, as indicated by elevated malondialdehyde (MDA) levels and a marked decline in the activity of antioxidant enzymes and reduced glutathione (GSH), and total antioxidant capacity (TAC) levels. Moreover, IMI treatment significantly downregulated the mRNA expression of steroidogenic genes and proliferating cell nuclear antigen (PCNA) immunoexpression in the testicular tissue. However, thymol co-administration significantly mitigated the IMI-induced toxic effects. Our findings suggested that IMI acts as a male reproductive toxicant in rats and thymol could be a potential therapeutic option for IMI reprotoxic impacts.


Assuntos
Apoptose/genética , Neonicotinoides/toxicidade , Nitrocompostos/toxicidade , Estresse Oxidativo/efeitos dos fármacos , Testículo/efeitos dos fármacos , Timol/farmacologia , Animais , Antioxidantes/metabolismo , Apoptose/efeitos dos fármacos , Masculino , Tamanho do Órgão/efeitos dos fármacos , Ratos , Espermatozoides/efeitos dos fármacos , Testosterona/sangue
20.
Ecotoxicology ; 30(6): 1126-1137, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34085160

RESUMO

Neonicotinoids and heavy metals pollution exist simultaneously in agro ecosystem. However, little is known about their combined ecotoxicological effects on non-target crop plants. We have selected imidacloprid (IMI) and cadmium (Cd), applied alone and in combination, to evaluate their effect on growth, physiological and biochemical parameters of tomato. Results showed that the single application of contaminants (IMI and/or Cd) adversely affected both the growth and chlorophyll pigment, and Cd alone application was more phytotoxic than IMI. However, their combined action aggravated the inhibitory effect and indicate a synergistic effect, but it exerted antagonistic effects on chlorophyll pigment inhibition compared with IMI and Cd alone treatments. Both chemicals increased hydrogen peroxide level and generated lipid peroxidation, and the co-contamination exacerbates oxidative stress by their synergistic effect. Those results implicate that disturbance of cellular redox status is the plausible mechanism for IMI and Cd induced toxicity. In conclusion, the single or combined IMI and Cd cause negative effects on tomatoes.


Assuntos
Lycopersicon esculentum , Cádmio/toxicidade , Ecossistema , Neonicotinoides/toxicidade , Nitrocompostos/toxicidade
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