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1.
Food Chem ; 367: 130653, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34343809

RESUMO

A uniform spherical structure covalent organic framework (TAPA-BPDA-COF) was prepared by a facile method at room temperature with tris(4-aminophenyl)amine (TAPA) and 4,4'-biphenyldicarboxaldehyde (BPDA) as building blocks. Based on the solid phase extraction with the TAPA-BPDA-COF as the sorbent and high performance liquid chromatography-diode array detection, a sensitive analytical method was established for the determination of four neonicotinoid insecticides from water and honey samples. Under the optimum conditions, good linear response for the quantification of the analytes was achieved in the range of 0.3-50.0 ng mL-1 for water samples and in the range of 8.0-500.0 ng g-1 for honey samples. The method recoveries fell in the range of 80.0-121.9% with RSDs less than 7.6%. The limits of detection at the signal to noise ratio of 3 were measured to be in the range of 0.08-0.12 ng mL-1 for water samples and 2.6-3.3 ng g-1 for honey samples, depending on compounds.


Assuntos
Inseticidas , Estruturas Metalorgânicas , Cromatografia Líquida de Alta Pressão , Limite de Detecção , Neonicotinoides , Extração em Fase Sólida
2.
Food Chem ; 367: 130740, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34375891

RESUMO

Traditional sample preparation methods for insecticide analysis are laborious and fatal to living organisms. In the work, an in vivo sampling rate calibrated-solid phase microextraction-gas chromatography-mass spectrometry method was established and successfully used for in vivo sampling and quantitative determination of three insecticides (hexachlorobenzene, fipronil and chlorfenapyr) by direct exposing micron-sized fiber in living garlic. Absorption, enrichment, migration and elimination behavior of insecticides in garlic were investigated. Bioaccumulative effects with obvious tissue differences were observed to all three insecticides, especially for chlorfenapyr. Bioconcentration factors (BCFs) ranging from 0.0342 to 1.0887 were obtained, and the closer to roots, the higher BCFs. The half-life of insecticides in garlic ranged from 0.43 to 0.96 d. In the first 24 h, 55.0% - 80.3% insecticides residues in garlic were eliminated with first-order elimination kinetics. The research provides in vivo insights into the environmental fates of insecticides in complex living system with minimized organism damage.


Assuntos
Alho , Inseticidas , Resíduos de Praguicidas , Cromatografia Gasosa-Espectrometria de Massas , Inseticidas/análise , Resíduos de Praguicidas/análise , Microextração em Fase Sólida
3.
Artigo em Chinês | MEDLINE | ID: mdl-34624954

RESUMO

In order to improve the clinical attention to the poisoning of chlorfenapyr, the diagnosis and treatment strategy of chlorfenapyr poisoning were discussed. This paper collected 4 cases of chlorfenapyr in the emergency department of the Second Hospital of Hebei Medical University and 4 cases of literature review, summarized the clinical characteristics of pesticide poisoning cases containing chlorfenapyr in China, and summarized and analyzed the clinical data of the cases. Seven of the 8 patients died from poisoning by chlorfenapyr. Exposure to chlorfenapyr through respiratory tract and digestive tract showed high mortality. Fever, hyperhidrosis, elevated muscle enzymes and progressive central nerve damage were its prominent clinical characteristics. Most of the initial symptoms of exposure were not serious. Some patients, especially those with low exposure dose, had a relatively stable stage with or without clinical diagnosis and treatment. In case of sweating, obvious fever and disturbance of consciousness, the condition would deteriorate rapidly, respiratory and circulatory failure and eventually die. With the increase of production capacity and market launch, people have more opportunities to be exposed to chlorfenapyr. It is urgent to strengthen the basic and clinical research of chlorfenapyr poisoning; Attention should be paid to the observation and treatment in the initial stable stage of poisoning, which can be used as a reference for the treatment of oxidative phosphoric acid dissolving coupling agent (sodium pentachlorophenol) poisoning.


Assuntos
Inseticidas , Piretrinas , China/epidemiologia , Humanos
4.
Braz J Biol ; 83: e248154, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34586191

RESUMO

The cotton boll weevil, Anthonomus grandis grandis Boheman (Coleoptera: Curculionidae), is a key cotton crop pest in Brazil. Adverse climatic factors, such as high temperatures and low soil moisture, dehydrate oviposited cotton squares (bud flowers) on the ground and cause high mortality of its offspring within these plant structures. The objective of this research was to evaluate the mortality of the cotton boll weevil in drip and sprinkler irrigated cotton crops. The experimental design was in randomized blocks with two treatments: drip (T1) and sprinkler (T2, control) irrigated cotton crops with sixteen replications. Each parcel had one emergence cage, installed between two cotton rows per irrigation system, with 37 cotton squares with opened oviposition punctures and yellowish bracts, to capture adult cotton boll weevils. The average number of boll weevils that emerged from the cotton squares and the causes of mortality at different development stages were determined per treatment. Third-generation life tables of the boll weevil were prepared using the natural mortality data in drip and sprinkler irrigation treatments and plus actual, apparent and indispensable mortality rates and the lethality of each mortality cause. We conclude that the application of water directly to the root zone of the plants in a targeted manner, using the drip irrigation system, can cause high mortality of the cotton boll weevil immature stages inside cotton squares fallen on the ground. This is because the cotton squares fallen on the drier and hotter soil between the rows of drip-irrigated cotton dehydrates causing the boll weevils to die. This is important because it can reduce its population density of the pest and, consequently, the number of applications of chemical insecticides for its control. Thus, contributing to increase the viability of cotton production, mainly in areas of the Brazilian semiarid region where the cotton is cultivated in organic system.


Assuntos
Besouros , Inseticidas , Gorgulhos , Animais , Produtos Agrícolas , Oviposição
5.
Zhongguo Xue Xi Chong Bing Fang Zhi Za Zhi ; 33(4): 387-395, 2021 Aug 24.
Artigo em Chinês | MEDLINE | ID: mdl-34505446

RESUMO

OBJECTIVE: To analyze the changes of small molecular metabolites in the larvae of a deltamethrin-sensitive strain of Anopheles sinensis following exposure to deltamethrin, so as to provide the scientific basis for investigating the metabolic pathway and screening metabolic markers of deltamethrin in An. sinensis. METHODS: The 50% and 75% lethal concentrations (LC50 and LC75) of deltamethrin against the larvae of a deltamethrin-sensitive strain of An. sinensis were calculated in laboratory. The type and content of An. sinensis larvae metabolites were detected using high performance liquid chromatography and mass spectrometry (LC-MS/MS) following exposure to deltamethrin at LC50 and LC75 for 30 min and 24 h, and the changes of metabolites were analyzed. RESULTS: The LC50 and LC75 values of deltamethrin were 4.36 × 10-3 µg/mL and 1.12 × 10-2 µg/mL against thelarvae of a deltamethrin-sensitive strain of An. sinensis. Following exposure of the larvae of a deltamethrin-sensitive strain of An. sinensis to deltamethrin at LC50 and LC75 for 30 min, the differential metabolites mainly included organic oxygen compounds, carboxylic acid and its derivatives, fatty acyl and pyrimidine nucleotides, with reduced glucose levels. Following exposure for 24 h, the differential metabolites mainly included organic oxygen compounds, carboxylic acid and its derivatives, aliphatic acyl and purine nucleotides, with increased glucose level detected. CONCLUSIONS: Carbohydrate, carboxylic acid and its derivatives, fatty acyls, amino acids and their derivatives may play important roles in deltamethrin metabolism in the larvae of a deltamethrin-sensitive strain of An. sinensis.


Assuntos
Anopheles , Inseticidas , Animais , Cromatografia Líquida , Larva , Nitrilas , Piretrinas , Espectrometria de Massas em Tandem
6.
Trials ; 22(1): 613, 2021 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-34507602

RESUMO

BACKGROUND: In cluster randomized trials (CRTs) of interventions against malaria, mosquito movement between households ultimately leads to contamination between intervention and control arms, unless they are separated by wide buffer zones. METHODS: This paper proposes a method for adjusting estimates of intervention effectiveness for contamination and for estimating a contamination range between intervention arms, the distance over which contamination measurably biases the estimate of effectiveness. A sigmoid function is fitted to malaria prevalence or incidence data as a function of the distance of households to the intervention boundary, stratified by intervention status and including a random effect for the clustering. The method is evaluated in a simulation study, corresponding to a range of rural settings with varying intervention effectiveness and contamination range, and applied to a CRT of insecticide treated nets in Ghana. RESULTS: The simulations indicate that the method leads to approximately unbiased estimates of effectiveness. Precision decreases with increasing mosquito movement, but the contamination range is much smaller than the maximum distance traveled by mosquitoes. For the method to provide precise and approximately unbiased estimates, at least 50% of the households should be at distances greater than the estimated contamination range from the discordant intervention arm. CONCLUSIONS: A sigmoid approach provides an appropriate analysis for a CRT in the presence of contamination. Outcome data from boundary zones should not be discarded but used to provide estimates of the contamination range. This gives an alternative to "fried egg" designs, which use large clusters (increasing costs) and exclude buffer zones to avoid bias.


Assuntos
Culicidae , Inseticidas , Malária , Animais , Humanos , Malária/prevenção & controle , Controle de Mosquitos , Ensaios Clínicos Controlados Aleatórios como Assunto
7.
Environ Monit Assess ; 193(10): 665, 2021 Sep 20.
Artigo em Inglês | MEDLINE | ID: mdl-34545435

RESUMO

Aedes aegypti is an important vector of dengue fever, dengue hemorrhagic fever and yellow fever, chikungunya, and Zika virus. The objective was to evaluate the resistance of A. aegypti exposed to insecticides with different action modes (deltamethrin, imidacloprid, and fipronil) under intense selection pressure for 10 generations in laboratory. Bioassays were conducted according to World Health Organization. Biochemical assay performed after selection with deltamethrin (Delta-SEL), fipronil (Fipro-SEL), and imidacloprid (Imida-SEL) from G1 to G10 was used for the assessment of detoxification enzymes (esterase (EST), acetylcholinesterase (AChE), glutathione S-transferases (GST), and acid and alkaline phosphatases (ACP and ALP)). The Fipro-SEL (G10) had high resistance (77-fold), whereas Delta-SEL and Imida-SEL populations presented very high resistance with 118 and 372-fold, respectively, in comparison with unselected (UNSEL). The levels of EST, AChE, GST, ACP, and ALP enzymes amplified on application from G1 to G10. The enzymes contributing in resistance development of insecticides were as follows: GST (20.7 µmol/min/mg of protein) in Delta-SEL (G10), while AChE 9.71 µmol/min/mg of protein in Imida-SEL (G10) and the peak ACP and ALP enzyme activities 13.32 and 12.93 µmol/min/mg of protein, respectively, in Fipro-SEL (G10). The results showed that detoxification enzymes trigger insecticide resistance in A. aegypti and their suppression may aid in the resistance breakage.


Assuntos
Aedes , Inseticidas , Piretrinas , Infecção por Zika virus , Zika virus , Acetilcolinesterase , Animais , Monitoramento Ambiental , Inseticidas/toxicidade , Larva , Mosquitos Vetores , Neonicotinoides , Nitrilas , Nitrocompostos , Pirazóis , Piretrinas/toxicidade
8.
Int J Mol Sci ; 22(17)2021 Aug 26.
Artigo em Inglês | MEDLINE | ID: mdl-34502147

RESUMO

Tetramethrin is a pyrethroid insecticide that is commonly used worldwide. The toxicity of this insecticide into the living system is an important concern. In this study, a novel tetramethrin-degrading bacterial strain named A16 was isolated from the activated sludge and identified as Gordonia cholesterolivorans. Strain A16 exhibited superior tetramethrin degradation activity, and utilized tetramethrin as the sole carbon source for growth in a mineral salt medium (MSM). High-performance liquid chromatography (HPLC) analysis revealed that the A16 strain was able to completely degrade 25 mg·L-1 of tetramethrin after 9 days of incubation. Strain A16 effectively degraded tetramethrin at temperature 20-40 °C, pH 5-9, and initial tetramethrin 25-800 mg·L-1. The maximum specific degradation rate (qmax), half-saturation constant (Ks), and inhibition constant (Ki) were determined to be 0.4561 day-1, 7.3 mg·L-1, and 75.2 mg·L-1, respectively. The Box-Behnken design was used to optimize degradation conditions, and maximum degradation was observed at pH 8.5 and a temperature of 38 °C. Five intermediate metabolites were identified after analyzing the degradation products through gas chromatography-mass spectrometry (GC-MS), which suggested that tetramethrin could be degraded first by cleavage of its carboxylester bond, followed by degradation of the five-carbon ring and its subsequent metabolism. This is the first report of a metabolic pathway of tetramethrin in a microorganism. Furthermore, bioaugmentation of tetramethrin-contaminated soils (50 mg·kg-1) with strain A16 (1.0 × 107 cells g-1 of soil) significantly accelerated the degradation rate of tetramethrin, and 74.1% and 82.9% of tetramethrin was removed from sterile and non-sterile soils within 11 days, respectively. The strain A16 was also capable of efficiently degrading a broad spectrum of synthetic pyrethroids including D-cyphenothrin, chlorempenthrin, prallethrin, and allethrin, with a degradation efficiency of 68.3%, 60.7%, 91.6%, and 94.7%, respectively, after being cultured under the same conditions for 11 days. The results of the present study confirmed the bioremediation potential of strain A16 from a contaminated environment.


Assuntos
Actinobacteria/metabolismo , Inseticidas/metabolismo , Piretrinas/metabolismo , Poluentes do Solo/metabolismo , Actinobacteria/crescimento & desenvolvimento , Biotransformação , Microbiologia Industrial/métodos
9.
J Agric Food Chem ; 69(39): 11572-11581, 2021 Oct 06.
Artigo em Inglês | MEDLINE | ID: mdl-34554742

RESUMO

A series of novel steroidal derivatives with a substituted 1,3,4-oxadiazole structure was designed and synthesized, and the target compounds were evaluated for their insecticidal activity against five aphid species. Most of the tested compounds exhibited potent insecticidal activity against Eriosoma lanigerum (Hausmann), Myzus persicae, and Aphis citricola. Compounds 20g and 24g displayed the highest activity against E. lanigerum, showing LC50 values of 27.6 and 30.4 µg/mL, respectively. Ultrastructural changes in the midgut cells of E. lanigerum were detected by transmission electron microscopy, indicating that these steroidal oxazole derivatives might exert their insecticidal activity by destroying the mitochondria and nuclear membranes in insect midgut cells. Furthermore, a field trial showed that compound 20g exhibited effects similar to those of the positive controls chlorpyrifos and thiamethoxam against E. lanigerum, reaching a control rate of 89.5% at a dose of 200 µg/mL after 21 days. We also investigated the hydrolysis and metabolism of the target compounds in E. lanigerum by assaying the activities of three insecticide-detoxifying enzymes. Compound 20g at 50 µg/mL exhibited inhibitory action on carboxylesterase similar to the known inhibitor triphenyl phosphate. The above results demonstrate the potential of these steroidal oxazole derivatives to be developed as novel pesticides.


Assuntos
Afídeos , Inseticidas , Praguicidas , Animais , Inseticidas/farmacologia , Oxidiazóis/farmacologia
10.
J Agric Food Chem ; 69(39): 11582-11591, 2021 Oct 06.
Artigo em Inglês | MEDLINE | ID: mdl-34555899

RESUMO

The ionotropic γ-aminobutyric acid (iGABA) receptor is commonly considered as a fast inhibitory channel and is an important insecticide target. Since 1990, RDL, LCCH3, and GRD have been successively isolated and found to be potential subunits of the insect iGABA receptor. More recently, one orphan gene named 8916 was found and considered to be another potential iGABA receptor subunit according to its amino acid sequence. However, little information about 8916 has been reported. Here, the 8916 subunit from Chilo suppressalis was studied to determine whether it can form part of a functional iGABA receptor by co-expressing this subunit with CsRDL1 or CsLCCH3 in the Xenopus oocyte system. Cs8916 or CsLCCH3 did not form functional ion channels when expressed alone. However, Cs8916 was able to form heteromeric ion channels when expressed with either CsLCCH3 or CsRDL1. The recombinant heteromeric Cs8916/LCCH3 channel was a cation-selective channel, which was sensitive to GABA or ß-alanine. The current of the Cs8916/LCCH3 channel was inhibited by dieldrin, endosulfan, fipronil, or ethiprole. In contrast, fluralaner, broflanilide, and avermectin showed little effect on the Cs8916/LCCH3 channel (IC50s > 10 000 nM). The Cs8916/RDL1 channel was sensitive to GABA, but was significantly different in EC50 and Imax for GABA to those of homomeric CsRDL1. Fluralaner, fipronil, or dieldrin showed antagonistic actions on Cs8916/RDL1. In conclusion, Cs8916 is a potential iGABA receptor subunit, which can interact with CsLCCH3 to generate a cation-selective channel that is sensitive to several insecticides. Also, as Cs8916/RDL1 has a higher EC50 than homomeric CsRDL1, Cs8916 may affect the physiological functions of CsRDL1 and therefore play a role in fine-tuning GABAergic signaling.


Assuntos
Inseticidas , Mariposas , Sequência de Aminoácidos , Animais , Inseticidas/farmacologia , Mariposas/metabolismo , Receptores de GABA/genética , Receptores de GABA/metabolismo , Receptores de GABA-A , Ácido gama-Aminobutírico
11.
J Environ Manage ; 299: 113611, 2021 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-34526283

RESUMO

The application of pesticides in agricultural and public health sectors has resulted in substantially contaminated water resources with residues in many countries. Almost no reviews have addressed pesticide residues in drinking water globally; calculated hazard indices for adults, children, and infants; or discussed the potential health risk of pesticides to the human population. The objectives of this article were to summarize advances in research related to pesticide residues in drinking water; conduct health risk assessments by estimating the daily intake of pesticide residues consumed only from drinking water by adults, children, and infants; and summarize options for pesticide removal from water systems. Approximately 113 pesticide residues were found in drinking water samples from 31 countries worldwide. There were 61, 31, and 21 insecticide, herbicide, and fungicide residues, respectively. Four residues were in toxicity class IA, 14 residues were in toxicity class IB, 55 residues were in toxicity class II, 17 residues were in toxicity class III, and 23 residues were in toxicity class IV. The calculated hazard indices (HIs) exceeded the value of one in many cases. The lowest HI value (0.0001) for children was found in Canada, and the highest HI value (30.97) was found in Egypt, suggesting a high potential health risk to adults, children, and infants. The application of advanced oxidation processes (AOPs) showed efficient removal of many pesticide classes. The combination of adsorption followed by biodegradation was shown to be an effective and efficient purification option. In conclusion, the consumption of water contaminated with pesticide residues may pose risks to human health in exposed populations.


Assuntos
Água Potável , Inseticidas , Resíduos de Praguicidas , Praguicidas , Poluentes Químicos da Água , Adulto , Criança , Água Potável/análise , Humanos , Inseticidas/análise , Resíduos de Praguicidas/análise , Praguicidas/análise , Poluentes Químicos da Água/análise
12.
Ecotoxicol Environ Saf ; 225: 112719, 2021 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-34478976

RESUMO

Dissipation of imidacloprid (IMI) and its metabolites (urea, olefin, 5-hydroxy, guanidine, 6-chloronicotinic acid) in Chinese prickly ash (CPA) was investigated using QuEChERS combined with UPLC-MS/MS. Good linearity (r2 ≥0.9963), accuracy (recoveries of 71.8-104.3%), precision (relative standard deviations of 0.9-9.4%), and sensitivity (limit of quantification ≤0.05 mg kg-1) were obtained. After application of IMI at dosage of 467 mg a.i. L-1 for three times with interval of 7 d, the dissipation dynamics of IMI in CPA followed first-order kinetics, with half-life of 6.48-7.29 d. IMI was the main compound in CPA, followed by urea and guanidine with small amounts of olefin, 5-hydroxy, and 6-chloronicotinic acid. The terminal residues of total IMI and its metabolites at PHI of 14-21 d were 0.16-7.80 mg kg-1 in fresh CPA and 0.41-10.44 mg kg-1 in dried CPA, with the median processing factor of 3.62. Risk assessment showed the acute (RQa) and chronic dietary risk quotients (RQc) of IMI in CPA were 0.020-0.083% and 0.052-0.334%, respectively. Based on the dietary structures of different genders and ages of Chinese people, the whole dietary risk assessment indicated that RQc was less than 100% for the general population except for 2- to 7-year-old children (RQc of 109.9%), implying the long-term risks of IMI were acceptable to common consumers except for children.


Assuntos
Inseticidas , Resíduos de Praguicidas , Zanthoxylum , Criança , Pré-Escolar , China , Cromatografia Líquida , Humanos , Inseticidas/análise , Neonicotinoides/análise , Nitrocompostos/análise , Resíduos de Praguicidas/análise , Medição de Risco , Espectrometria de Massas em Tandem
13.
Ecotoxicol Environ Saf ; 225: 112743, 2021 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-34481350

RESUMO

Fluralaner, a systemic pesticide, was originally registered with the US Food and Drug Administration in 2014 under the trade name Bravecto for flea treatment for pets. As a GABA antagonist, the footprint of fluralaner has expended beyond medical and veterinary pests in recent years. In this study, we examined the acute toxicity of fluralaner against three pests of Henosepilachna vigintioctopunctata, Megalurothrips usitatus, and Phyllotreta striolata in the Solanaceae, Fabaceae, and Cruciferae families, respectively, and the sublethal impact of fluralaner on Propylaea japonica, a widely distributed predatory ladybeetle. Based on LC50, fluralaner was effective against H. vigintioctopunctata (0.098 mg a.i. L-1 for the second instar larvae), M. usitatus (0.134 mg a.i. L-1 for adult females), and P. striolata (0.595 mg a.i. L-1 for adults). For P. japonica, however, fluralaner was substantially less effective (1.177 mg a.i. L-1 for the third instar larvae). Furthermore, the LC10 and LC30 of P. japonica were also consistently higher than the LC50 of the three pests. In addition, we did not observe any significant impacts of fluralaner at LC10 and LC30 on the life history traits, including body weight, developmental time, pre-oviposition period, and fecundity of P. japonica. Based on our results from acute toxicities and sublethal impacts, fluralaner is effective against vegetable pests, while potentially friendly to P. japonica when employed as a biological control agent.


Assuntos
Besouros , Inseticidas , Animais , Humanos , Inseticidas/toxicidade , Isoxazóis/toxicidade , Comportamento Predatório , Estados Unidos , Verduras
14.
Malar J ; 20(1): 388, 2021 Sep 29.
Artigo em Inglês | MEDLINE | ID: mdl-34587958

RESUMO

BACKGROUND: Female mosquitoes serve as vectors for a host of illnesses, including malaria, spread by the Plasmodium parasite. Despite monumental strides to reduce this disease burden through tools such as bed nets, the rate of these gains is slowing. Ongoing disruptions related to the COVID-19 pandemic may also negatively impact gains. The following scoping review was conducted to examine novel means of reversing this trend by exploring the efficacy of insecticide-treated window screens or eaves to reduce Anopheles mosquito bites, mosquito house entry, and density. METHODS: Two reviewers independently searched PubMed, Scopus, and ProQuest databases on 10 July, 2020 for peer-reviewed studies using insecticide-treated screens or eaves in malaria-endemic countries. These articles were published in English between the years 2000-2020. Upon collection, the reports were stratified into categories of biting incidence and protective efficacy, mosquito entry and density, and mosquito mortality. RESULTS: Thirteen out of 2180 articles were included in the final review. Eaves treated with beta-cyfluthrin, transfluthrin or bendiocarb insecticides were found to produce vast drops in blood-feeding, biting or mosquito prevalence. Transfluthrin-treated eaves were reported to have greater efficacy at reducing mosquito biting: Rates dropped by 100% both indoors and outdoors under eave ribbon treatments of 0.2% transfluthrin (95% CI 0.00-0.00; p < 0.001). Additionally, co-treating window screens and eaves with polyacrylate-binding agents and with pirimiphos-methyl has been shown to retain insecticidal potency after several washes, with a mosquito mortality rate of 94% after 20 washes (95% CI 0.74-0.98; p < 0.001). CONCLUSIONS: The results from this scoping review suggest that there is value in implementing treated eave tubes or window screens. More data are needed to study the longevity of screens and household attitudes toward these interventions.


Assuntos
Anopheles/fisiologia , Habitação/normas , Insetos Vetores/fisiologia , Inseticidas , Malária/prevenção & controle , Animais , Anopheles/efeitos dos fármacos , Feminino , Mordeduras e Picadas de Insetos/prevenção & controle , Insetos Vetores/efeitos dos fármacos , Malária/transmissão
15.
Toxicon ; 201: 141-147, 2021 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-34474068

RESUMO

Liriodenine is a biologically active plant alkaloid with multiple effects on mammals, fungi, and bacteria, but has never been evaluated for insecticidal activity. Accordingly, liriodenine was applied topically in ethanolic solutions to adult female Anopheles gambiae, and found to be mildly toxic. Its lethality was synergized in mixtures with dimethyl sulfoxide and piperonyl butoxide. Recordings from the ventral nerve cord of larval Drosophila melanogaster showed that liriodenine was neuroexcitatory and reversed the inhibitory effect of 1 mM GABA at effective concentrations of 20-30 µM. GABA antagonism on the larval nervous system was equally expressed on both susceptible and cyclodiene-resistant rdl preparations. Acutely isolated neurons from Periplaneta americana were studied under patch clamp and inhibition of GABA-induced currents with an IC50 value of about 1 µM were observed. In contrast, bicuculline did not reverse the effects of GABA on cockroach neurons, as expected. In silico molecular models suggested reasonable structural concordance of liriodenine and bicuculline and isosteric hydrogen bond acceptor sites. This study is the first assessing of the toxicology of liriodenine on insects and implicates the GABA receptor as one likely neuronal target, where liriodenine might be considered an active chemical analog of bicuculline.


Assuntos
Aporfinas , Inseticidas , Animais , Aporfinas/toxicidade , Drosophila melanogaster , Feminino , Inseticidas/toxicidade , Receptores de GABA
16.
Nanoscale ; 13(37): 15647-15658, 2021 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-34532728

RESUMO

Nanocapsules are a promising controlled release formulation for foliar pest control. However, the complicated process and high cost limit widespread use in agriculture, so a simpler and more convenient preparation system is urgently needed. Meanwhile, under complex field conditions, the advantageous mechanism of the nanosize effect and sustained release have no quantitative and detailed study. In this study, a reactive emulsifier (OP-10) is used to participate in the interfacial polymerization of the nanoemulsion, and polymer nanocapsules loaded with lambda-cyhalothrin (NCS@LC) are quickly and easily prepared to study the efficacy and synergistic mechanism of foliar pest control. As a result, the nanocapsule is about 150 nm with a stable core-shell structure. The nanoscale state increases the distribution and adhesion of the particles on the leaf surface, which increases the contact efficiency of pesticides under the different physiological stages and behavioral activities of the target organism. The shell structure provides sustained release characteristics and increases the UV resistance by about 2.5 times for pesticides. Compared with microcapsules loaded with lambda-cyhalothrin (CS@LC), NCS@LC not only shows rapid and synergistic insecticidal efficacy but also provides sustained insecticidal efficacy. The mortality of NCS is 3.4 times that of the nanosized emulsion in water (NEW) at the lowest concentration (0.5 mg L-1), and the control efficacy remained 77.3% after 7 days. Compared with NEW, NCS@LC provides excellent field efficacy, while LC50 for zebrafish is only 0.68 times without increasing the aquatic toxicity risk.


Assuntos
Inseticidas , Nanocápsulas , Piretrinas , Animais , Nanocápsulas/toxicidade , Nitrilas , Peixe-Zebra
17.
Ig Sanita Pubbl ; 78(4): 564-582, 2021.
Artigo em Italiano | MEDLINE | ID: mdl-34525014

RESUMO

BACKGROUND: Countries in sub-Saharan Africa remain the most affected by malaria, with nearly 93% of cases and 94% of deaths in 2018 according to the World Health Organization (WHO). According to the WHO, in order to significantly reduce malaria- related incidence and mortality, at least 80% of the population should be covered with insecticide-treated mosquito nets (ITNs). Hence our objective which was on the one hand to determine the rates in terms of possession and use of ITNs in countries located in Sub- Saharan Africa between January 2015 and January 2020, and to determine the impact of the use of ITNs on the probability of being infected with malaria. METHODS: To achieve our goal, we conducted a systematic literature review followed by a meta-analysis. The article search was done in the Scopus, Medline via Ovid, BioRxiv, MedRxiv, Google and Google scholar databases. Data extracted from articles included in the meta-analysis were represented as P-value, Odds Ratio (OR) and 95% confidence interval (CI). RESULTS: We obtained 693 article references published between 2015 and 2020, of which 54 were used in our work. Of these articles, 20 were used to analyze association between ITNs use and the probability of being infected with malaria. We noted an average rate in terms of possession of 75.8%±15.2 and in terms of use of 58.3%±18. This represents a gap of approximately 43.1%±19.2. Many factors was significantly associated with this level of use. These included the wealth quintile, the number of children under 5 in the household, the education level of the head of the household, and the knowledge that sleeping under a mosquito net protects against malaria. Finally, we determined, basis on the meta-analysis, that ITNs use is significantly associated (OR=0.53; 95%CI=[0.45-0.62]) with a decrease in the probability of being infected with malaria. CONCLUSION: The results of this study highlight the huge gap between ITN ownership and use. It is therefore important to increase information and awareness campaigns on the importance of ITNs use against malaria in communities.


Assuntos
Mosquiteiros Tratados com Inseticida , Inseticidas , Malária , África ao Sul do Saara/epidemiologia , Criança , Humanos , Malária/epidemiologia , Malária/prevenção & controle , Controle de Mosquitos
18.
Braz J Biol ; 83: e240842, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34550279

RESUMO

This research aimed to investigate various mosquitocidal activities of Chenopodium botrys whole- plant n-hexane extract against Culex quinquefasciatus. The extract showed remarkable larvicidal, pupicidal, adulticidal, oviposition deterrent and adult emergence inhibitory activities against Cx. quinquefasciatus. During the larvicidal and pupicidal activities, the 24-hour lethal concentration (LC50) of extract against 2nd instar larvae, 4th instar larvae and pupae were 324.6, 495.6 and 950.8 ppm, respectively. During the CDC (Centers for Disease Control and Prevention) bottle bioassay for adulticidal activity, the median knockdown times (KDT50) at 1.25% concentration was 123.4 minutes. During the filter paper impregnation bioassay for adulticidal activity, the KDT50 value at 0.138 mg/cm2 concentration was 48.6 minutes. The extract was fractionated into 14 fractions through silica gel column chromatography which were then combined into six fractions on the basis of similar retention factor (Rf) value. These fractions were screened for adulticidal activity by applying CDC bottle bioassay. The fraction obtained through 60:40 to 50:50% n-hexanes-chloroform mobile phase with 0.5 Rf value showed 100% adulticidal activity at 0.2% concentration. During oviposition deterrent activity, the highest concentration (1000 ppm) showed 71.3 ± 4.4% effective repellence and 0.6 ± 0.1 oviposition activity index. During adult emergence inhibition activity, the median emergence inhibition (EI50) value was 312.3 ppm. From the outcome of the present investigation, it is concluded that the n-hexane extract of C. botrys whole- plant possesses strong larvicidal, pupicidal, adulticidal, oviposition deterrent and adult emergence inhibitory activities against Cx. quinquefasciatus.


Assuntos
Chenopodium , Culex , Inseticidas , Animais , Hexanos , Inseticidas/farmacologia , Larva , Extratos Vegetais/farmacologia , Folhas de Planta
19.
Braz J Biol ; 83: e250373, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34550295

RESUMO

Honey is a suitable matrix for the evaluation of environmental contaminants including organochlorine insecticides. The present study was conducted to evaluate residues of fifteen organochlorine insecticides in honey samples of unifloral and multifloral origins from Dir, Pakistan. Honey samples (5 g each) were extracted with GC grade organic solvents and then subjected to Rotary Evaporator till dryness. The extracts were then mixed with n-Hexane (5 ml) and purified through Column Chromatography. Purified extracts (1µl each) were processed through Gas Chromatograph coupled with Electron Capture Detector (GC-ECD) for identification and quantification of the insecticides. Of the 15 insecticides tested, 46.7% were detected while 53.3% were not detected in the honey samples. Heptachlor was the most prevalent insecticide with a mean level of 0.0018 mg/kg detected in 80% of the samples followed by ß-HCH with a mean level of 0.0016 mg/kg detected in 71.4% of the honey samples. Honey samples from Acacia modesta Wall. were 100% positive for Heptachlor with a mean level of 0.0048 mg/kg followed by ß-HCH with a mean level of 0.003 mg/kg and frequency of 83.3%. Minimum levels of the tested insecticides were detected in the unifloral honey from Ziziphus jujuba Mill. Methoxychlor, Endosulfan, Endrin and metabolites of DDT were not detected in the studied honey samples. Some of the tested insecticides are banned in Pakistan but are still detected in honey samples indicating their use in the study area. The detected levels of all insecticides were below the Maximum Residue Levels (MRLs) and safe for consumers. However, the levels detected can cause mortality in insect fauna. The use of banned insecticides is one of the main factors responsible for the declining populations of important insect pollinators including honeybees.


Assuntos
Mel , Inseticidas , Resíduos de Praguicidas , Animais , Abelhas , Endossulfano/análise , Biomarcadores Ambientais , Mel/análise , Inseticidas/toxicidade , Resíduos de Praguicidas/análise , Resíduos de Praguicidas/toxicidade
20.
Chemosphere ; 283: 131447, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34467951

RESUMO

Chlorpyrifos (CPF) falls under the category of organophosphorus pesticides which are in huge demand in the agricultural sector. Overuse of this pesticide has led to the degradation of the quality of terrestrial and aquatic life. The chemical is moderately persistent in the environment but its primary metabolite 3,5,6-trichloro-2-pyridinol (TCP) is comparatively highly persistent. Thus, it is important to degrade the chemical and there are many proposed techniques of degradation. Out of which bioremediation is considered to be highly cost-effective and efficient. Many previous studies have attempted to isolate appropriate microbial strains to degrade CPF which established the fact that chlorine atoms released while mineralising TCP inhibits further proliferation of microorganisms. Thus, it has been increasingly important to experiment with strains that can simultaneously degrade both CPF and TCP. In this review paper, the need for degrading CPF specifically the problems related to it has been discussed elaborately. Alongside these, the metabolism pathways undertaken by different kinds of microorganisms have been included. This paper also gives a detailed insight into the potential strains of microorganisms which has been confirmed through experiments conducted previously. It can be concluded that a wide range of microorganisms has to be studied to understand the possibility of applying bioremediation in wastewater treatment to remove pesticide residues. In addition to this, in the case of recalcitrant pesticides, options of treating it with hybrid techniques like bioremediation clubbed with photocatalytic biodegradation can be attempted.


Assuntos
Clorpirifos , Inseticidas , Praguicidas , Compostos Organofosforados , Piridonas
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