RESUMO
In recent decades, the common and the tropical bed bugs have experienced a resurgence in many parts of the world. The evolution of insecticide resistance in bed bug populations is considered a significant factor contributing to this resurgence. We analyzed samples of Cimex lectularius L. and Cimex hemipterus (F.) from Europe (Spain 41, Switzerland 2, the Czech Republic 1), Asia (Hong Kong 34), North America (USA 14, Mexico 3), and South America (Colombia 3) to assess the prevalence and mechanisms of insecticide resistance. We identified specimens morphologically and barcoded them by sequencing the mitochondrial Cytochrome c oxidase subunit I (COI) and the 16S ribosomal RNA (16S rRNA) genes. Additionally, we screened segments of the voltage-gated sodium channel (VGSC) and the nicotinic acetylcholine receptor (nAChR) genes for point mutations associated with insecticide resistance and measured the activity of detoxifying enzymes. All samples from North America and Europe were identified as C. lectularius, whereas specimens from Hong Kong were C. hemipterus. Out of 64 C. lectularius samples tested for knockdown resistance (kdr) mutations, 90.6% contained at least 1 known mutation. All 35 C. hemipterus samples exhibited kdr mutations. A new mutation was identified in the pyrethroid target site in both common (F1524C) and tropical (F1450C) bed bugs. No resistance-associated mutations in the nAChR gene were found. Several populations that exhibited kdr mutations also showed elevated activity of detoxifying enzymes. The high frequency of kdr-associated mutations in bed bug populations from Spain and Hong Kong limits the efficacy of pyrethroids for their control.
Assuntos
Percevejos-de-Cama , Resistência a Inseticidas , Inseticidas , Animais , Percevejos-de-Cama/genética , Resistência a Inseticidas/genética , Inseticidas/farmacologia , Inativação Metabólica , Proteínas de Insetos/genética , Proteínas de Insetos/metabolismo , RNA Ribossômico 16S/análise , Receptores Nicotínicos/genética , Receptores Nicotínicos/metabolismo , Europa (Continente) , Complexo IV da Cadeia de Transporte de Elétrons/metabolismo , Complexo IV da Cadeia de Transporte de Elétrons/genéticaRESUMO
BACKGROUND: Synergists reduce insecticide metabolism in mosquitoes by competing with insecticides for the active sites of metabolic enzymes, such as cytochrome P450s (CYPs). This increases the availability of the insecticide at its specific target site. The combination of both insecticides and synergists increases the toxicity of the mixture. Given the demonstrated resistance to the classical insecticides in numerous Anopheles spp., the use of synergists is becoming increasingly pertinent. Tropical plants synthesize diverse phytochemicals, presenting a repository of potential synergists. METHODS: Extracts prepared from medicinal plants found in Jamaica were screened against recombinant Anopheles gambiae CYP6M2 and CYP6P3, and Anopheles funestus CYP6P9a, CYPs associated with anopheline resistance to pyrethroids and several other insecticide classes. The toxicity of these extracts alone or as synergists, was evaluated using bottle bioassays with the insecticide permethrin. RNA sequencing and in silico modelling were used to determine the mode of action of the extracts. RESULTS: Aqueous extracts of Piper amalago var. amalago inhibited CYP6P9a, CYP6M2, and CYP6P3 with IC50s of 2.61 ± 0.17, 4.3 ± 0.42, and 5.84 ± 0.42 µg/ml, respectively, while extracts of Kalanchoe pinnata, inhibited CYP6M2 with an IC50 of 3.52 ± 0.68 µg/ml. Ethanol extracts of P. amalago var. amalago and K. pinnata displayed dose-dependent insecticidal activity against An. gambiae, with LD50s of 368.42 and 282.37 ng/mosquito, respectively. Additionally, An. gambiae pretreated with K. pinnata (dose: 1.43 µg/mosquito) demonstrated increased susceptibility (83.19 ± 6.14%) to permethrin in a bottle bioassay at 30 min compared to the permethrin only treatment (0% mortality). RNA sequencing demonstrated gene modulation for CYP genes in anopheline mosquitoes exposed to 715 ng of ethanolic plant extract at 24 h. In silico modelling showed good binding affinity between CYPs and the plants' secondary metabolites. CONCLUSION: This study demonstrates that extracts from P. amalago var. amalago and K. pinnata, with inhibitory properties, IC50 < 6.95 µg/ml, against recombinant anopheline CYPs may be developed as natural synergists against anopheline mosquitoes. Novel synergists can help to overcome metabolic resistance to insecticides, which is increasingly reported in malaria vectors.
Assuntos
Anopheles , Inseticidas , Kalanchoe , Extratos Vegetais , Anopheles/efeitos dos fármacos , Animais , Extratos Vegetais/farmacologia , Extratos Vegetais/química , Inseticidas/farmacologia , Kalanchoe/química , Sinergistas de Praguicidas/farmacologia , Proteínas de Insetos/metabolismo , Proteínas de Insetos/genéticaRESUMO
BACKGROUND: Aedes aegypti is the primary vector of dengue, chikungunya, and Zika viruses in Colombia. Various insecticides, including pyrethroid, organophosphate, and carbamate insecticides; growth regulators; and biological insecticides, such as Bacillus thuringiensis var. israelensis, have been used to control Ae. aegypti populations. However, organophosphates such as malathion, pirimiphos-methyl, and temephos have been used over the last decade owing to the high resistance to pyrethroids. METHODS: This study assessed the susceptibility to organophosphates in 14 Ae. aegypti populations from the Córdoba department in northern Colombia. Moreover, possible resistance mechanisms were investigated by determining the activity levels of α-esterases, ß-esterases, mixed function oxidases (MFOs), glutathione S-transferases (GSTs), and insensitive acetylcholinesterase (iAChE). Additionally, the Ace-1 gene was sequenced to identify mutations at the target site of action. RESULTS: The populations were susceptible to temephos and malathion but resistant to fenitrothion, and in three of them, to pirimiphos-methyl. Alterations in the enzyme activity levels of α-esterases and ß-esterases, GST, and iAChE were observed among the populations, with high enzyme activity levels of α and ß esterases associated with resistance to fenitrothion. No mutations were identified in the Ace-1 gene. CONCLUSIONS: These findings are highly relevant for vector control programs in the region, as they allow for adjustments in resistance management strategies and improve the effectiveness of interventions against these arboviruses.
Assuntos
Aedes , Resistência a Inseticidas , Inseticidas , Mosquitos Vetores , Organofosfatos , Animais , Aedes/efeitos dos fármacos , Aedes/genética , Colômbia , Resistência a Inseticidas/genética , Inseticidas/farmacologia , Mosquitos Vetores/efeitos dos fármacos , Mosquitos Vetores/genética , Organofosfatos/farmacologia , Acetilcolinesterase/metabolismo , Acetilcolinesterase/genética , Glutationa Transferase/genética , Glutationa Transferase/metabolismo , Temefós/farmacologia , Esterases/metabolismo , Esterases/genética , Proteínas de Insetos/genética , Proteínas de Insetos/metabolismoRESUMO
Nanotechnology has been a promising plant protection discipline in recent years, attributed to the unique physicochemical properties exhibited at the nanoscale. In this context, silver nanoparticles (AgNPs) have been effective in various applications, including medical, industrial, and agronomic, and during the last few years, the control of insect pests has raised great interest. The present review mainly provides updated information about the use of AgNPs elaborated by different synthesis methods, such as biological (plants, microorganisms), physical, and chemical, and their effect against various insect species of agricultural importance belonging to the order Diptera, Coleoptera, Lepidoptera, and Hemiptera. The physiological and toxic effects of applying AgNPs are reported and characterized by developmental problems, mortality, weight reduction, interference with enzymatic activity, and anomalies in the life cycle. Moreover, in the final section, the action mechanisms through which AgNPs act on insects are also discussed, highlighting mechanisms such as alteration of transmembrane permeability, interruption of DNA replication, alteration of protein synthesis, and production of reactive oxygen species (ROS).
Assuntos
Insetos , Inseticidas , Nanopartículas Metálicas , Prata , Prata/química , Prata/farmacologia , Nanopartículas Metálicas/química , Nanopartículas Metálicas/toxicidade , Animais , Insetos/efeitos dos fármacos , Inseticidas/química , Inseticidas/farmacologia , Agricultura/métodos , Espécies Reativas de Oxigênio/metabolismoRESUMO
BACKGROUND: Dengue is an emerging disease in Argentina due to the colonization of Aedes aegypti, the mosquito vector. Buenos Aires Province is the biggest and most populated district in Argentina, suffering dengue outbreaks of growing magnitude. During epidemic periods, pyrethroid insecticides are used in this country to control adult mosquitoes. Pyrethroid resistance in dengue vectors has been reported worldwide, making it necessary to implement resistance management strategies. The voltage-gated sodium channel is the target site of pyrethroids. Mutations in the gene encoding this protein, called kdr mutations, are usually the molecular cause of pyrethroid resistance in insects. In Ae. aegypti from the Americas, three kdr substitutions were described: V410L, V1016I, and F1534C. The diagnostic of kdr mutations is recommended for the early detection of pyrethroid resistance as well as the consequent planning of evidence-based control policies. METHODS: We distributed ovitraps across 16 localities in Buenos Aires Province, collecting 22,123 eggs. A total of 522 mosquitoes were genotyped in positions 1016 and 1534 of voltage-gated channel using multiplex high-resolution melting and/or TaqMan probe methods. A subset of 449 samples was also genotyped by a singleplex high-resolution melting method developed ad hoc and/or Sanger sequencing. RESULTS: We have documented, for the first time to our knowledge in the central region of Argentina, the presence of the 1016Ikdr + 1534Ckdr allele. Additionally, our study reports the first identification of the V410L mutation in central Argentina. These results underscore a growing trend of pyrethroid resistance in Ae. aegypti, fueled by the widespread use of these insecticides. CONCLUSIONS: We detected 1016Ikdr + 1534Ckdr and 410Lkdr mutations in central Argentina for the first time and improved the processivity and accuracy of kdr genotyping methods. The results are both a tool for resistance monitoring and a sign of alarm to direct efforts towards finding sustainable methods for vector control to complement or replace pyrethroids. Joint efforts between academia and authorities to develop and implement public policies for vector control are a productive way to transfer scientific results for their application in public health.
Assuntos
Aedes , Genótipo , Resistência a Inseticidas , Inseticidas , Mosquitos Vetores , Mutação , Piretrinas , Canais de Sódio Disparados por Voltagem , Animais , Aedes/genética , Aedes/efeitos dos fármacos , Piretrinas/farmacologia , Resistência a Inseticidas/genética , Argentina , Inseticidas/farmacologia , Mosquitos Vetores/genética , Mosquitos Vetores/efeitos dos fármacos , Canais de Sódio Disparados por Voltagem/genética , Dengue/transmissão , Proteínas de Insetos/genética , FemininoRESUMO
Aedes albopictus (Skuse) is a competent vector of dengue and Zika viruses in Mexico. Monitoring the level of resistance of local population is essential due to its epidemiological significance. This study aimed to identify mutations in the voltage-gated sodium channel (VGSC) as one of the mechanisms responsible for pyrethroid insecticide resistance in Ae. albopictus. Immature samples were collected in a rural town in Yucatan, Mexico, from May to October 2021. The pyrethroid insecticide lambda-cyhalothrin was impregnated in CDC bottles and bioassays were conducted on Ae. albopictus populations 3-5 days after emergence. The mosquitoes were susceptible to the insecticide. Females were taken for total DNA extraction. Fragments of domains II, III, and IV of the voltage-gated sodium channel (VGSC) were amplified and sequenced. The presence of synonymous and non-synonymous mutations was found in positions 1532 and 1534 of domain III of the sodium channel gene (VGSC). No mutant alleles in domain IV were detected. A homozygous mutant (ACG) coding for the amino acid threonine (1008Thr) was identified in domain II. Domain III included three heterozygous alleles (P1528S, L1530S, and Ile1410Thr). This last heterozygous allele is reported for the first time in Mexico. Homozygous mutants encoding the amino acids serine/serine and serine/proline in domain III were observed. These have been reported in Aedes aegypti from Mexico, but not yet in Ae. albopictus. This represents new findings for the region, as Ae. albopictus has only been introduced there for approximately five years. In conclusion, non-synonymous mutations were found in Ae. albopictus in a rural area of Yucatan, emphasizing the importance of integrated vector control to prevent Asian tiger mosquitoes from spreading these resistant alleles.
Assuntos
Aedes , Resistência a Inseticidas , Inseticidas , Mutação , Piretrinas , Canais de Sódio Disparados por Voltagem , Animais , Aedes/genética , Aedes/efeitos dos fármacos , Resistência a Inseticidas/genética , Piretrinas/farmacologia , Canais de Sódio Disparados por Voltagem/genética , México , Feminino , Inseticidas/farmacologia , Mosquitos Vetores/genética , Mosquitos Vetores/efeitos dos fármacos , Nitrilas/farmacologiaRESUMO
BACKGROUND: Visceral leishmaniasis (VL) is a zoonotic disease caused by Leishmania infantum and transmitted by the sand fly Lutzomyia longipalpis. Dogs are the major domestic reservoir of L. infantum. To prevent the spread of the disease, dog collars impregnated with 4% deltamethrin have been effectively used in VL endemic areas. However, this approach may contribute to the emergence of insecticide resistance in sand flies. Therefore, it is important to characterize the susceptibility of different populations of Lu. longipalpis to deltamethrin in areas where insecticide-impregnated dog collars are used. METHODS: Six field sand fly populations from Brazil were exposed to deltamethrin in CDC bottle bioassays at the diagnostic doses (DD) of 21.9 µg/bottle and 30 µg/bottle. For the dose-response (DR) experiments, doses of 1, 3, 5, 7, 9 and 11 µg/bottle of deltamethrin were used to impregnate bottles; control group bottles were impregnated with acetone only. Each bottle contained an average of 20 sand flies, both male and female, and they were exposed to either deltamethrin or acetone for 60 min. RESULTS: Based on the DD of 21.9 µg/bottle, three populations were susceptible to deltamethrin. In contrast, two populations collected from the states of Ceará and Minas Gerais exhibited mortality rates of 94.9% and 95.7%, indicating possible resistance, and one population from the state of Ceará showed resistance, with a mortality rate of 87.1%. At the DD of 30 µg/bottle, two populations from the states of Ceará and Piauí showed possible resistance, while the other four populations were susceptible. The resistance ratio (RR50) ranged from 2.27 to 0.54, and RR95 ranged from 4.18 to 0.33, indicating a low resistance intensity. CONCLUSIONS: This study established a DD for Lu. longipalpis using the CDC bottle bioassay. We found that Lu. longipalpis populations in three Brazilian states where insecticide-impregnated dog collars were used for VL control were susceptible to deltamethrin. However, one population in Ceará State was classified as resistant to deltamethrin. These results contribute to the current knowledge on sand fly resistance and surveillance, and highlight the need for a better understanding of the resistance mechanisms of Lu. longipalpis in areas where insecticide-impregnated dog collars have been widely used.
Assuntos
Resistência a Inseticidas , Inseticidas , Leishmaniose Visceral , Nitrilas , Psychodidae , Piretrinas , Animais , Piretrinas/farmacologia , Psychodidae/efeitos dos fármacos , Psychodidae/parasitologia , Nitrilas/farmacologia , Inseticidas/farmacologia , Leishmaniose Visceral/prevenção & controle , Leishmaniose Visceral/transmissão , Cães , Feminino , Brasil , Masculino , Doenças do Cão/prevenção & controle , Doenças do Cão/parasitologia , Doenças do Cão/transmissão , Leishmania infantum/efeitos dos fármacos , Controle de Insetos/métodos , Insetos Vetores/efeitos dos fármacos , Insetos Vetores/parasitologiaRESUMO
Triatoma species from the phyllosoma subcomplex are sympatrically distributed and include some of the main vectors of Chagas disease in Mexico. Species within this subcomplex, including Triatoma pallidipennis, T. mazzottii, T. picturata, and T. longipennis, have shown resistance to pyrethroid insecticides, associated with mutations in the para gene of the voltage gate sodium channel (VGSC) and the activity of detoxifying enzymes such as ß-esterases and glutathione s-transferases (GST). In this study, we evaluated resistance to deltamethrin in hybrids of T. pallidipennis × T. mazzottii (T.pal × T.maz) and T. pallidipennis × T. picturata (T.pal × T.pic) under laboratory conditions, and the inheritance was determined based on the degree of dominance (DO). Additionally, associated resistance mechanisms were analyzed, including detoxifying enzymes and knockdown resistance (kdr) mutations. High levels of resistance to deltamethrin were found in the hybrids of T.pal × T.maz when compared with the susceptible strain of T. mazzottii (RR50 = 17.50). Dominance levels calculated for each hybrid showed values < - 1, confirming that resistance to deltamethrin was recessive. Hybrids exhibited reduced α-, ß-esterases, and cytochrome P450 mixed-function oxidases (MFO) activity. However, both hybrids showed significantly increased GST activity, particularly in T.pal × T.pic, suggesting enhanced detoxification through this pathway. The kdr mutation A943V, present in T. mazzottii, was found in T.pal × T.maz hybrids. These results emphasize the importance of considering hybridization in resistance management programs and its potential impact on the success of insecticide-based control measures.
Assuntos
Resistência a Inseticidas , Inseticidas , Mutação , Nitrilas , Piretrinas , Triatoma , Piretrinas/farmacologia , Triatoma/genética , Triatoma/efeitos dos fármacos , Triatoma/enzimologia , Animais , Nitrilas/farmacologia , Resistência a Inseticidas/genética , México , Inseticidas/farmacologia , Glutationa Transferase/genética , Glutationa Transferase/metabolismo , Inativação Metabólica/genética , Esterases/genética , Esterases/metabolismo , FemininoRESUMO
Current study provides insight on the feasibility of polylactic acid (PLA) integrated with (1:1 ratio) of essential oils belonging to Ocimum gratissimum (OG) and Mentha spicata (MS) for prevention of major stored insect pests (Sitophilus oryzae and Oryzophilus surinamensis) in Sorghum and Pearl millet. A combination of OG and MS essential oils (1:1) was incorporated into the PLA polymer matrix. Further, SPME analysis of synthesized PLA showed the presence of volatiles corresponding to carvone (6.44 %) and thymol (6.22 %). Synthesized PLA composites were tested against S. oryzae and O. surinamensis using Sorghum and Pearl millets, and insect mortality was equivalent to commercial super bags (CSB). The head space oxygen decreased significantly in CSB and slightly in PLA bags. Thickness of EO blended PLA composite was increased (99 µm), tensile strength (23.94 MPa), WVTR (1.42 g/m2.hr) analysis, significant folding ability, and swelling capacity (0.24 %) showed slight reduction in composite film. TGA showed good thermal stability (334ËC) and XRD displayed the increased crystallinity (38.35 %) in PLAOM films, SEM and FTIR analysis of the synthesized composite films revealed complete homogenization of EO and PLA matrix. In addition, SEM analysis of insects (control & treated) revealed less topology changes in the elytra. Biodegradability study confirmed the weight loss in PLA films. Hence, current approach of using composite EO's with PLA offers sustainable solution for prevention of infestation during storage of millets.
Assuntos
Inseticidas , Óleos Voláteis , Pennisetum , Poliésteres , Sorghum , Poliésteres/química , Animais , Inseticidas/química , Inseticidas/farmacologia , Óleos Voláteis/química , Óleos Voláteis/farmacologia , Sorghum/química , Pennisetum/química , Resistência à Tração , Gorgulhos/efeitos dos fármacos , Estudos de ViabilidadeRESUMO
BACKGROUND: Ae. aegypti mosquitoes are considered a global threat to public health due to its ability to transmit arboviruses such as yellow fever, dengue, Zika and Chikungunya to humans. The lack of effective arboviral vaccines and etiological treatments make vector control strategies fundamental in interrupting the transmission cycle of these pathogens. This study evaluated Ae. aegypti mosquito populations pre- and post-intervention period with disseminating stations of the larvicide pyriproxyfen to understand its potential influence on the genetic structure and population diversity of these vectors. METHODOLOGY/PRINCIPAL FINDINGS: This study was conducted in Manacapuru city, Amazonas, Brazil, where 1,000 pyriproxyfen dissemination stations were deployed and monitored from FEB/2014 to FEB/2015 (pre-intervention) and AUG/2015 to JAN/2016 (post-intervention). Low-coverage whole genome sequencing of 36 individuals was performed, revealing significant stratification between pre- and post-intervention groups (pairwise FST estimate of 0.1126; p-value < 0.033). Tajima's D estimates were -3.25 and -3.07 (both p-value < 0.01) for pre- and post-intervention groups, respectively. Molecular diversity estimates (Theta(S) and Theta(Pi)) also showed divergences between pre- and post-intervention groups. PCA and K-means analysis showed clustering for SNP frequency matrix and SNP genotype matrix, respectively, being both mainly represented by the first principal component. PCA and K-means clustering also showed significant results that corroborate the impact of pyriproxyfen intervention on genetic structure populations of Ae. aegypti mosquitoes. CONCLUSIONS/SIGNIFICANCE: The results revealed a bottleneck effect and reduced mosquito populations during intervention, followed by reintroduction from adjacent and unaffected populations by this vector. We highlighted that low-coverage whole genome sequencing can contribute to genetic and structure population data, and also generate important information to aid in genomic and epidemiological surveillance.
Assuntos
Aedes , Inseticidas , Controle de Mosquitos , Mosquitos Vetores , Piridinas , Animais , Aedes/efeitos dos fármacos , Aedes/genética , Piridinas/farmacologia , Brasil , Controle de Mosquitos/métodos , Mosquitos Vetores/efeitos dos fármacos , Mosquitos Vetores/genética , Inseticidas/farmacologia , Feminino , Humanos , Variação GenéticaRESUMO
Aedes aegypti is an important vector of arboviruses, including dengue, chikungunya and Zika. The application of synthetic insecticides is a frequently used strategy to control this insect. Malathion is an organophosphate insecticide that was widely used in Brazil in the 1980s and 1990s to control the adult form of A. aegypti. In situations where resistance to currently used insecticides is detected, the use of malathion may be resumed as a control measure. Many studies have confirmed resistance to malathion, however, comparative studies of differential gene expression of the entire transcriptome of resistant and susceptible insects are scarce. Therefore, understanding the molecular basis of resistance to this insecticide in this species is extremely important. In this paper, we present the first transcriptomic description of susceptible and resistant strains of A. aegypti challenged with malathion. Guided transcriptome assembly resulted in 39,904 transcripts, where 2133 differentially expressed transcripts were detected, and three were validated by RT-qPCR. Enrichment analysis for these identified transcripts resulted in 13 significant pathways (padj < 0.05), 8 associated with down-regulated and 5 with up-regulated transcripts in treated resistant insects. It was possible to divide the transcripts according to the mechanism of action into three main groups: (i) genes involved in detoxification metabolic pathways; (ii) genes of proteins located in the membrane/extracellular region; and (iii) genes related to DNA integration/function. These results are important in advancing knowledge of genes related to resistance mechanisms in this insect, enabling the development of effective technologies and strategies for managing insecticide resistance.
Assuntos
Aedes , Resistência a Inseticidas , Inseticidas , Malation , Transcriptoma , Malation/farmacologia , Animais , Aedes/genética , Aedes/efeitos dos fármacos , Resistência a Inseticidas/genética , Inseticidas/farmacologia , Transcriptoma/efeitos dos fármacos , Transcriptoma/genética , Perfilação da Expressão Gênica/métodos , Mosquitos Vetores/genética , Mosquitos Vetores/efeitos dos fármacos , Proteínas de Insetos/genética , Proteínas de Insetos/metabolismoRESUMO
The use of botanical insecticides has increased in recent years due to the demand for effective products, particularly against insects resistant to conventional insecticides. Among these is Aedes aegypti, a well-adapted mosquito to urban environments that opportunistically feeds on humans and animals, contributing to the spread of virus. We evaluated the potential of essential oils (EOs) extracted from Eucalyptus citriodora, Eucalyptus staigeriana, Eucalyptus caryophyllus, and Mentha arvensis in terms of their larvicidal activity against Ae. aegypti. EOs' compounds were determined using gas chromatography-mass spectrometry (GC-MS). Bioassays were performed on third instar larvae of Ae. aegypti to evaluate the larvicidal effects of EO dilutions in dimethyl sulfoxide (DMSO) at different concentrations. Mortality rates were observed over a 72-hour period to determine the efficacy of the treatments. Citronellal (86.64) predominated in E. citriodora, limonene in E. staigeriana (41.68), eugenol in E. caryophyllus (87.76), and menthol in M. arvensis (51.53%). EOs exhibited larvicidal activity from 10 ppm, with notable efficacy at 85 ppm, in which those from E. staigeriana and M. arvensis caused maximum mortality to Ae. aegypti larvae. Results revealed distinct efficacy patterns among EOs, with E. staigeriana displaying high toxicity within 24 h, achieving LC50 and LC95 values of 47.04 ppm and 97.35 ppm, respectively. Larvicidal effects within 1 h were observed for E. citriodora and E. caryophyllus. This study underscores larvicidal efficacy against Ae. aegypti, notably E. staigeriana, which had the lowest LC50 value. The findings indicate that the tested samples have potential for use as bioinsecticides.
Assuntos
Aedes , Cromatografia Gasosa-Espectrometria de Massas , Inseticidas , Larva , Óleos Voláteis , Animais , Aedes/efeitos dos fármacos , Óleos Voláteis/farmacologia , Óleos Voláteis/química , Inseticidas/farmacologia , Larva/efeitos dos fármacos , Eucalyptus/química , Bioensaio , Dose Letal MedianaRESUMO
CONTEXT: Drosophila suzukii (Matsumura, 1931) is a widespread agricultural pest responsible for significant damage to various soft-skinned fruit hosts. The revolutionary potential of bioinformatics in agriculture emerges from its ability to provide extensive information on pests, fungi, chemical resistance, implications of non-target species, and other critical aspects. This wealth of information allows researchers to engage in projects and applied research in diverse agricultural domains that face these challenges. In this context, bioinformatics tools play a fundamental role. The negative impact of pests on crops, resulting in substantial economic losses, has highlighted the importance of in silico methods. METHODS: To achieve this, we conducted a systematic search in scientific databases using as keywords "Drosophila suzukii," "biopesticides," "simulations computational," and "in-silico." After applying the filters of relevance and publication date, we organized the articles and prioritized those that directly addressed that matched the keywords and the use of bioinformatics tools. Additionally, we included studies focusing on in silico assays of biopesticides, such as molecular docking. Our review aimed to present a collection of recent literature on biopesticides against Drosophila suzukii, emphasizing bioinformatics methods. Through this work, we strive to contribute to the literature of new perspectives on the development and efficiency of biopesticides, along with to advance research that may improve pest control strategies. RESULTS: In the results of the systematic review, we found 2734 articles related to the selected keywords. Six of these articles directly address Drosophila suzukii and the use of bioinformatics tools in the search for alternatives in pest control. In the selected studies, we observed that two articles tend to focus on phylogenetic approaches, searching for gene sequences, amino acids, and constructing phylogenetic trees. The other three articles used molecular modeling and docking of receptors such as GABA and TRP with plant-derived and synthetic compounds to study intermolecular interactions. However, we identified gaps in these studies that could lead to further research in the biorational development of biopesticides using bioinformatics tools.
Assuntos
Drosophila , Inseticidas , Animais , Biologia Computacional/métodos , Drosophila/efeitos dos fármacos , Inseticidas/química , Inseticidas/farmacologia , Simulação de Acoplamento Molecular , Praguicidas/química , Praguicidas/farmacologiaRESUMO
This study aimed to evaluate the toxicity of Piper hispidinervum essential oil (PHEO) against 11 Brazilian populations of Sitophilus zeamais (Coleoptera: Curculionidae). The effects of sublethal doses of PHEO on the behavior (walking and flying), respiration, and population growth (ri) of the insect populations were investigated. PHEO toxicity was determined through concentration-mortality bioassays, with mortality curves established using increasing PHEO concentrations ranging from 140.00 to 1000.00 µL kg-1. Behavior was evaluated based on walking distance, walking time, walking speed, walking time proportion, flight height, and flight takeoff success. Respiration was measured via the respiratory rate, while population growth (ri) was assessed through the instantaneous growth rate. All 11 populations of S. zeamais were susceptible to PHEO, showing no signs of resistance. The populations exhibited varying behavioral and physiological responses to sublethal exposure to PHEO, indicating different mitigation strategies. The results confirm that PHEO possesses insecticidal potential for controlling S. zeamais populations. However, the observed behavioral and physiological responses should be considered when establishing control measures in pest management programs for stored products.
Assuntos
Inseticidas , Óleos Voláteis , Piper , Gorgulhos , Animais , Óleos Voláteis/farmacologia , Óleos Voláteis/química , Gorgulhos/efeitos dos fármacos , Gorgulhos/fisiologia , Piper/química , Inseticidas/farmacologia , Inseticidas/toxicidade , Comportamento Animal/efeitos dos fármacos , Óleos de Plantas/farmacologia , Óleos de Plantas/químicaRESUMO
Piper aduncum L., a Brazilian medicinal plant, is known for its bioactive properties, including repellent and insecticidal effects. This study investigated the insecticidal potential of essential oils (EOs) from P. aduncum, collected during the dry and rainy seasons, against fleas (Ctenocephalides felis felis Bouché, 1835) in egg and adult stages. The EOs were obtained by hydrodistillation using a modified Clevenger apparatus for 2 h. Qualitative and quantitative analysis were performed via gas chromatography. The findings revealed that dillapiole was the predominant substance in both EOs, accounting for 77.6% (rainy) and 85.5% (dry) of the EOs. These EOs exhibited high efficacy against the parasite C. felis felis, resulting in 100% egg mortality at a concentration of 100 µg/mL and 100% mortality for adult fleas starting from 1,000 µg/mL. Dillapiole standard was also effective but at a relatively high concentration. This finding suggested that EOs from P. aduncum exhibit cytotoxicity against these pests and might hold potential for commercial production, offering practical applications for such bioprospecting. This study uniquely revealed that the EOs from P. aduncum, which is rich in dillapiole, demonstrated pulicidal activity against the parasite C. felis felis, particularly in inhibiting the hatching of the eggs of these parasites.
Assuntos
Ctenocephalides , Inseticidas , Óleos Voláteis , Piper , Animais , Óleos Voláteis/farmacologia , Óleos Voláteis/química , Piper/química , Inseticidas/farmacologia , Ctenocephalides/efeitos dos fármacos , Óleos de Plantas/farmacologia , Controle de InsetosRESUMO
BACKGROUND: Microbial larvicides containing both LysiniBacillus sphaericus and Bacillus thuringiensis svar. israelensis (Bti) insecticidal crystals can display advantages for mosquito control. This includes a broader action against larvae that are refractory to the Binary (Bin) toxin from L. sphaericus, as Bin-resistant Culex quinquefasciatus and Aedes aegypti naturally refractory larvae, which often co-habit urban areas of endemic countries for arboviruses. Our principal goal was to assess the toxicity of a combined L. sphaericus/Bti larvicide (Vectomax FG™) to Cx. quinquefasciatus (susceptible CqS and Bin-resistant CqR) and Ae. aegypti (Rocke) and to determine its persistence in the breeding sites with those larvae. METHODS: The toxicity of a combined L. sphaericus/Bti product (VectoMax FG™) to larvae was performed using bioassays, and persistence was evaluated in simulate field trials carried out under the shade, testing two label concentrations during 12 weeks. A laboratory strain SREC, established with CqS and CqR larvae, was kept during four generations to evaluate the ability of the L. sphaericus/Bti to eliminate resistant larvae. RESULTS: The L. sphaericus/Bti showed toxicity (mg/L) to larvae from all strains with a decreasing pattern for CqS (LC50 = 0.006, LC90 = 0.030), CqR (LC50 = 0.009, LC90 = 0.069), and Rocke (LC50 = 0.042, LC90 = 0.086). In a simulated field trial, the larvicide showed a persistence of 6 weeks and 8 weeks, controlling larvae from all strains in containers with 100 L of water, using 2 g or 4 g per container (100 L), respectively. The treatment of SREC larvae with L. sphaericus/Bti showed its capacity to eliminate the Bin-resistant individuals using suitable concentrations to target those larvae. CONCLUSIONS: Our results showed the high efficacy and persistence of the L. sphaericus/Bti larvicide to control Cx. quinquefasciatus and Ae. aegypti that might cohabit breeding sites. These findings demonstrated that such larvicides can be an effective tool for controlling those species in urban areas with a low potential for selecting resistance.
Assuntos
Aedes , Bacillaceae , Bacillus thuringiensis , Culex , Inseticidas , Larva , Controle de Mosquitos , Controle Biológico de Vetores , Animais , Culex/efeitos dos fármacos , Aedes/efeitos dos fármacos , Larva/efeitos dos fármacos , Controle de Mosquitos/métodos , Inseticidas/farmacologia , Bacillaceae/química , Controle Biológico de Vetores/métodos , Resistência a Inseticidas , Mosquitos Vetores/efeitos dos fármacosRESUMO
Forensic entomology plays a crucial role in estimating the minimum postmortem interval through the study of insect larvae found at crime scenes. The precision of this estimation relies on various biotic and abiotic elements that simultaneously influence insect growth and development, encompassing factors such as temperature, humidity, photoperiod, diet, and the existence of xenobiotics in decomposing tissues. Despite numerous studies on the influence of these factors, including the impact of xenobiotics, there are currently no robust tools available for making corrections to this estimation considering concurrently all variables. In an attempt to propose an exploratory and descriptive statistical model to analyze the simultaneous effect and interaction of different variables on larval growth, this study aimed to compare the effect of malathion on the growth of Megaselia scalaris (Loew, 1866) (Diptera: Phoridae) raised in malathion-spiked porcine muscle, under controlled and uncontrolled temperature and humidity conditions (environmental conditions). Larvae were also reared using various growth media. A split-plot design that combined crossed and nested factors was employed; 2 linear mixed models were developed to assess the relationships between the variables. The model provides valuable insights into the complex interactions among xenobiotics, growth media, and environmental conditions in the size and development of M. scalaris.
Assuntos
Dípteros , Entomologia Forense , Inseticidas , Larva , Malation , Animais , Malation/farmacologia , Larva/crescimento & desenvolvimento , Larva/efeitos dos fármacos , Dípteros/crescimento & desenvolvimento , Dípteros/efeitos dos fármacos , Inseticidas/farmacologia , Modelos Lineares , SuínosRESUMO
Aedes aegypti and Aedes albopictus are responsible for transmitting major human arboviruses such as Dengue, Zika, and Chikungunya, posing a global threat to public health. The lack of etiological treatments and efficient vaccines makes vector control strategies essential for reducing vector population density and interrupting the pathogen transmission cycle. This study evaluated the impact of long-term pyriproxyfen exposure on the genetic structure and diversity of Ae. aegypti and Ae. albopictus mosquito populations. The study was conducted in Manaus, Amazonas, Brazil, where pyriproxyfen dissemination stations have been monitored since 2014 up to the present day. Double digest restriction-site associated DNA sequencing was performed, revealing that despite significant local population reductions by dissemination stations with pyriproxyfen in various locations in Brazil, focal intervention has no significant impact on the population stratification of these vectors in urban scenarios. The genetic structuring level of Ae. aegypti suggests it is more stratified and directly affected by pyriproxyfen intervention, while for Ae. albopictus exhibits a more homogeneous and less structured population. The results suggest that although slight differences are observed among mosquito subpopulations, intervention focused on neighborhoods in a capital city is not efficient in terms of genetic structuring, indicating that larger-scale pyriproxyfen interventions should be considered for more effective urban mosquito control.
Assuntos
Aedes , Mosquitos Vetores , Piridinas , Aedes/genética , Aedes/efeitos dos fármacos , Animais , Piridinas/farmacologia , Brasil , Mosquitos Vetores/genética , Mosquitos Vetores/efeitos dos fármacos , Controle de Mosquitos/métodos , Inseticidas/farmacologia , Variação Genética , HumanosRESUMO
BACKGROUND: Aedes aegypti (L.) is the main vector of dengue, yellow fever, Zika, and chikungunya viruses in many parts of the world, impacting millions of people worldwide each year. Insecticide-based interventions have been effective in controlling Aedes mosquito populations for several years, but in recent times, resistance to these compounds has developed, posing a global threat to the control of this mosquito. METHODS: Ovitraps were used to collect A. aegypti eggs in the cities of Tartagal and San Ramón de la Nueva Orán (Salta), Puerto Iguazú (Misiones), and Clorinda (Formosa). World Health Organization (WHO)-impregnated papers with the discriminating concentration (DC) of permethrin, 5X, 10X and pirimiphos methyl were used for the toxicological bioassays. We also genotyped each sample for the three kdr single nucleotide polymorphisms (SNP): V410L, V1016I, and F1534C in individual TaqMan quantitative PCR (qPCR) reactions. RESULTS: All investigated A. aegypti populations were highly resistant to permethrin, as the mortality percentage with the permethrin 10×DC remained below 98%. However, all populations were 100% susceptible to pirimiphos-methyl. Kdr genotyping demonstrated the presence of the V410L mutation for the first time in Argentina in all the populations studied. A prevalence of the triple mutant genotype (LL + II + CC) was observed in the northeastern cities of Clorinda (83.3%) and Puerto Iguazú (55.6%). CONCLUSIONS: This study demonstrates for the first time the presence and intensity of resistance to permethrin in different populations from Argentina, and correlates the observed phenotype with the presence of kdr mutations (genotype).
Assuntos
Aedes , Resistência a Inseticidas , Inseticidas , Mosquitos Vetores , Mutação , Aedes/efeitos dos fármacos , Aedes/genética , Animais , Argentina , Resistência a Inseticidas/genética , Inseticidas/farmacologia , Mosquitos Vetores/genética , Mosquitos Vetores/efeitos dos fármacos , Permetrina/farmacologia , Polimorfismo de Nucleotídeo Único , GenótipoRESUMO
Resistance to insecticides is one of the great challenges that vector control programs must face. The constant use of pyrethroid-type insecticides worldwide has caused selection pressure in populations of the Aedes aegypti vector, which has promoted the emergence of resistant populations. The resistance mechanism to pyrethroid insecticides most studied to date is target-site mutations that desensitize the voltage-gated sodium channel (VGSC) of the insect to the action of pyrethroids. In the present study, susceptibility to the pyrethroid insecticides permethrin, lambda-cyhalothrin, and deltamethrin was evaluated in fourteen populations from the department of Córdoba, Colombia. The CDC bottle bioassay and WHO tube methods were used. Additionally, the frequencies of the F1534C, V1016I, and V410L mutations were determined, and the association of resistance with the tri-locus haplotypes was examined. The results varied between the two techniques used, with resistance to permethrin observed in thirteen of the fourteen populations, resistance to lambda-cyhalothrin in two populations, and susceptibility to deltamethrin in all the populations under study with the CDC method. In contrast, the WHO method showed resistance to the three insecticides evaluated in all populations. The frequencies of the mutated alleles ranged from 0.05-0.43 for 1016I, 0.94-1.0 for 1534C, and 0.01-0.59 for 410L. The triple homozygous mutant CIL haplotype was associated with resistance to all three pyrethroids evaluated with the WHO bioassay, while with the CDC bioassay, it was only associated with resistance to permethrin. This study highlights the importance of implementing systematic monitoring of kdr mutations, allowing resistance management strategies to be dynamically adjusted to achieve effective control of Aedes aegypti.