Search Results (131)

Bemisia tabaci (Aleyrodidae family) is one of the most damaging pests of numerous crops worldwide. Insecticides, namely pyrethroids and organophosphates, have long been the primary control tools against this pest, resulting in several resistance cases. In Tunisia, the two most damaging biotypes of B. tabaci, MEAM1-B and MED-Q, are sympatric, and more concerns about developing resistance keep rising due to the extensive use of insecticides. Here, we aimed to elucidate the molecular mechanism of resistance to pyrethroids and organophosphorus insecticides in two Tunisian populations of B. tabaci, collected respectively on Capsicum annuum and Lantana camara, and then determine the bacterial community associated with insecticide resistance and susceptible biotypes based on 16S rRNA Illumina sequencing. The results showed that the population collected on Capsicum annuum belonged to the MEAM1-B biotype with an insecticide resistance profile. In contrast, the population collected on the Lantana camara belonged to the MED-Q biotype with a sensitive profile. The bacterial communities of the two biotypes were predominantly structured by the Proteobacteria phylum and three genera, including Candidatus Portiera, the secondary facultative symbiont, and Hamiltonella, which were unevenly distributed between the two biotopes. Our results provide the first evidence for insecticide resistance alleles in Tunisian MEAM1-B populations and suggest an association between bacterial community composition within susceptible biotypes and insecticide resistance. Full article

Drug-induced autoimmune hepatitis (DIAIH) is a relatively new subtype of idiosyncratic drug-induced liver injury (iDILI), but the features of DIAIH have been variably described due to the inhomogeneity of assessed study cohorts. The aim of this analysis is to harmonize DIAIH cohorts by unifying causality assessments, which may help characterize the features of DIAIH. Methods: Published reports of DIAIH cases were evaluated for the causality assessment methods used to verify the diagnosis of DIAIH. This disorder consists of two parts, i.e., the iDILI part and the autoimmune (AIH) part, whereby each part needs a specific diagnostic algorithm. The validated and scoring Roussel Uclaf Causality Assessment (RUCAM) is privileged for assessing the iDILI part, and the validated, simplified AIH score is the perfect choice for evaluating the AIH part. The analysis of DIAIH publications revealed that 12/20 reports (60%) presented cases assessed by both the RUCAM and the simplified AIH score, providing 49 drugs and drug combinations as causative drugs in up to 25 cases of DIAIH. Serum alanine aminotransferase activities of up to 3489 UL and high titers of autoimmune parameters such as anti-nuclear antibodies, anti-smooth-muscle antibodies, and soluble liver antigen antibodies supported DIAIH diagnosis. In contrast, 4/20 reports (20%) applied only RUCAM, and 2/20 reports (10%) used only the simplified AIH score; these 6 reports therefore provided insufficient criteria for a valid DIAIH diagnosis. Moreover, 2/20 reports (10%) did not use any causality algorithm, providing elusive features of DIAIH. While DIAIH is clearly restricted to drugs as responsible agents, this term is erroneously used to refer to disease induced by non-drugs such as herbs, green tea, dimethoate (an organophosphate insecticide), dietary supplements, biologics, herbal remedies, different viruses, and bacteria, as well as vaccines. For diseases induced by these agents, a better term could be, for instance, non-drug-induced autoimmune hepatitis. Drug cessation and immunotherapy with corticosteroids and azathioprine comprise the treatment of choice. The characteristics of DIAIH can best be described if both the RUCAM and the simplified AIH score are used concomitantly. Full article

Background: Indoor residual spraying (IRS) is a core insecticide-based vector control tool employed in most malaria-affected settings globally. However, mosquito vectors have developed resistance to nearly all of the insecticides currently used in IRS. This has necessitated a transition to new classes of insecticides, from mostly using dichlorodiphenyltrichloroethane (DDT) and pyrethroids from 1997 to 2010 to carbamates in 2011 and organophosphates in 2013. In addition, other vector control measures, like the use of long-lasting insecticide-treated bed nets (LLINs), have also been employed for malaria control. Despite the implementation of these mosquito vector control interventions, malaria remains a disease of public health concern, especially in sub-Saharan Africa, which bears over 90% of the disease burden. This review will thus collate evidence on the effectiveness of IRS for malaria control in sub-Saharan Africa. Methods and analysis: The systematic review will be conducted following a priori criteria developed using the PRISMA guidelines. Articles will be obtained through a search of the Web of Science, Google Scholar, Medline via PubMed, Scopus and Embase databases. Mesh terms and Boolean operators (“AND”, “OR”) will be used in the article search. Additionally, websites of malaria research institutions will be searched. The article search will be conducted by two independent librarians (AAK and RS). All identified articles will be transferred to EPPI-reviewer v6.15.1.0 software. Article screening and data abstraction will be performed in duplicate by four reviewers (KOO, LN, GK and MO), and any further disagreements will be resolved through discussion and consensus. We shall extract data on the country, region, study design, insecticide combination, season, susceptibility procedure used, vector control interventions, population, mosquito species, malaria incidence or prevalence, insecticide efficacy, susceptibility, genotypic resistance, vector mortality and knockdown effect. Data analysis will be performed using STATA v17.0. Effect sizes will be statistically pooled using inverse-variance-weighted random-effects meta-analysis. Heterogeneity and publication bias in the articles will be assessed using the I² statistic and a funnel plot, respectively. For the studies that will not be included in the meta-analysis, a narrative synthesis will be written following the Cochrane Consumer and Communication Review Group format. Results: The findings of this review will help generate evidence on the effectiveness of indoor residual spraying using WHO pre-qualified insecticides in malaria control in sub-Saharan Africa. This protocol was registered in PROSPERO, registration number CRD42024517119. Full article

Stored product pests are controlled primarily through applying pyrethroid and organophosphate insecticides or through fumigation with phosphine (PH₃). However, several populations of weevils are resistant to these insecticides. Essential oils appear to be safe alternatives for both humans and the environment. The objective was to investigate the toxicity of Piper aduncum essential oil (PAEO) to Sitophilus zeamais and evaluate its effects on corn grain quality during the four-month storage period. This study was conducted in two stages. In the first stage, the toxicity of PAEO at concentrations lethal to 50 and 95% of insects (LC₅₀ and LC₉₅) was estimated. The second step evaluated the degree of infestation, water content, apparent specific mass, loss of mass, electrical conductivity, and percentage of germination of grains at 0, 30, 60, 90, and 120 days after exposure to PAEO, deltamethrin (pyrethroid), and the control treatment. PAEO presents toxicity to S. zeamais. The LC₅₀ and LC₉₅ values are 298.50 µL kg⁻¹ and 585.20 µL kg⁻¹, respectively. The increases in infestation degree, water content, electric conductivity, and mass loss, as well as reductions in apparent specific mass and germination, show the loss of corn quality during the 120-day storage period, being more significant when no product is applied. PAEO delays the loss of quality of the grains, presenting a greater capacity to preserve the grains for a longer period. Full article

A surge has been observed in the use of pesticides to boost agricultural yield in order to feed the continuously increasing human population. Different types and classes of broad-spectrum insecticides are in use, and the number is constantly increasing with the introduction of new ones. Keeping in view the broad-spectrum effects of organophosphate pesticides including Malathion (MLN), their use is continuously increasing without appraising their toxic impacts on non-target organisms. The continuous rise in the use of MLN has led to its presence, persistence, and transport to water bodies globally, subsequently affecting commercially valuable aquatic organisms. The current study was conducted to assess MLN-induced hematological and biochemical toxicities in the brain of a commercially valuable indigenous major carp, rohu, Labeo rohita. The fish was exposed to an acute concentration of commercial-grade MLN. The LC₅₀ of MLN (5 µg/L) led to behavioral inconsistencies and subtle impacts on the hematology (an increase in white blood cells and a reduction in red blood cells, hemoglobin, packed cell volume level, and mean corpuscular hemoglobin concentration) and biochemistry (an increase in reactive oxygen species, lipid peroxidation, activities of antioxidant enzymes (catalase, peroxidase, superoxide dismutase, glutathione, glutathione reductase, glutathione peroxidase, and glutathione-S-transferase) but a reduction in total protein content and activity of Na⁺/K⁺ ATPases) in the brain tissues. MLN also inhibited the activity of Acetylcholinesterase, while it led to an increase in Acetylcholine. Significant changes were observed in the serum biochemical profile; for example, glucose, cholesterol, potassium, urea, and total bilirubin increased, whereas total protein, sodium, chloride, albumin, and inorganic phosphate decreased after exposure. The current study clearly classified MLN as highly toxic to rohu. Therefore, the extra-judicious use of MLN should be strictly supervised. Studies concerning the real-world concentration of pesticides should be carried out on regular basis to mitigate the echoing issue of pesticide-based pollution. Full article

Chlorpyrifos (CPF) is a broad-spectrum organophosphate insecticide. Long-term exposure to low levels of CPF is associated with neurodevelopmental and neurodegenerative disorders. The mechanisms leading to these effects are still not fully understood. Normal NMDA receptor (NMDAR) function is essential for neuronal development and higher brain functionality, while its inappropriate stimulation results in neurological deficits. Thus, the current study aimed to investigate the role of NMDARs in CPF-induced neurotoxicity. We show that NMDARs mediate CPF-induced excitotoxicity in differentiated human fetal cortical neuronal ReNcell CX stem cells. In addition, by using two-electrode voltage clamp electrophysiology of Xenopus oocytes expressing NMDARs, we show CPF potentiation of both GluN1-1a/GluN2A (EC₅₀ ≈ 40 nM) and GluN1-1a/GluN2B (EC₅₀ ≈ 55 nM) receptors, as well as reductions (approximately halved) in the NMDA EC₅₀s and direct activation by 10 μM CPF of both receptor types. In silico molecular docking validated CPF’s association with NMDARs through relatively high affinity binding (−8.82 kcal/mol) to a modulator site at the GluN1–GluN2A interface of the ligand-binding domains. Full article

Chlorpyrifos (CPF) is an organophosphate insecticide that is extensively utilized globally due to its effectiveness against over 200 pest species. CPF exhibits its toxicity primarily through the inhibition of the acetylcholinesterase (AChE) enzyme, while mitochondrial damage and dysfunction have also been observed. The present study quantified the transcript levels of mitochondria protein-coding genes (mtPCGs) using quantitative real-time polymerase chain reaction (RT-qPCR) in samples of larvae of three dragonfly species (A. parthenope, E. elegans, and G. confluens) under different levels of CPF stress. By exposing larvae from uncontaminated populations to 0.05 μg/L CPF for 24 h, the transcript levels of seven mtPCGs in A. parthenope were significantly increased (p < 0.05) by 1.89 ± 0.42-fold for COI, 4.30 ± 0.24-fold for COIII, 5.94 ± 0.17-fold for ND1, 4.69 ± 0.56-fold for ND2, 3.44 ± 0.48-fold for ND4, 2.19 ± 0.53-fold for ND4L, and 5.05 ± 0.36-fold for Cytb, respectively. In E. elegans, the transcript levels of ND1, ND2, and ND4 increased by 1.23 ± 0.15, 1.48 ± 0.31, and 1.98 ± 0.25-fold, respectively (p < 0.05). In G. confluens, the transcript levels of COI, COIII, and ND4 increased by 1.56 ± 0.13, 1.50 ± 0.26, and 3.74 ± 0.40-fold, respectively (p < 0.01). It was demonstrated that the transcript levels of different mtPCGs showed significant up-regulation in the three different dragonfly larvae under CPF stress in the absence of mortality. ND4 was significantly increased in all three species, indicating that it is an important target gene. The present study underscores the response of mitochondrial gene expression in larvae of three different species in response to CPF pollutants, indicating that pesticide influences can potentially alter mitochondrial gene expression and potentially act as a method for assessing aquatic ecosystem health. Full article

Objectives: Growing evidence suggests a link between organophosphate insecticides and depression disorder. These chemicals are metabolized and subsequently expelled through the urinary tract. The present study aims to investigate whether dialkyl phosphate metabolites associate with depression score and severity among the general population. Methods: This cross-sectional study used data from the National Health and Nutrition Examination Survey (NHANES). Depression was evaluated by the Patient Health Questionnaire-9 (PHQ-9). All urinary dialkyl phosphate metabolites were quantitatively analyzed. The survey’s complex design parameters and sampling weights were considered. Results: 3035 eligible individuals were included. The estimated prevalence of mild and major depression was 18.3% (95% confidence interval [CI]: 16.9–19.7%) and 9.9% (95% CI: 8.7–11.0%). For each incremental unit in the level of urinary dimethyl phosphate (DMP), individuals were found to have a higher depression score of 0.77 and a significantly increased odds ratio (OR) of 1.13 (95% CI: 1.12–1.13) for mild depression and 2.75 (95% CI: 2.74–2.76) for major depression. Conclusions: Our findings indicate positive and independent associations between urinary dialkyl phosphate metabolites and an elevated risk of depression among the general population. Full article

Dichlorvos (2,2-dichlorovinyl dimethyl phosphate, DDVP) is a highly toxic organophosphorus insecticide, and its persistence in air, water, and soil poses potential threats to human health and ecosystems. Covalent triazine frameworks (CTFs), with their sufficient visible-light harvesting capacity, ameliorated charge separation, and exceptional redox ability, have emerged as promising candidates for the photocatalytic degradation of DDVP. Nevertheless, pure CTFs lack effective oxidative active sites, resulting in elevated reaction energy barriers during the photodegradation of DDVP. In this work, density functional theory (DFT) calculations were employed to investigate the impact of various oxygen-containing acid groups (-COOH, -HSO₃, -H₂PO₃) on DDVP photodegradation performance. First, simulations of the structure and optical properties of modified CTFs reveal that oxygen-containing acid groups induce surface distortion and result in a redshift in the absorption edge. Subsequently, analysis of the density of states, frontier molecular orbitals, surface electrostatic potential, work function, and dipole moment demonstrates that oxygen-containing acid groups enhance CTF polarization, facilitate charge separation, and ameliorate their oxidative capability. Additionally, the free-energy diagram of DDVP degradation uncovers that oxygen-containing acid groups lower the energy barrier by elevating the adsorption and activation capability of DDVP. Notably, -H₂PO₃ presents optimal potential for the photodegradation of DDVP by unique electronic structure and activation capability. This work offers a valuable reference for the development of oxygen-containing acid CTF-based photocatalysts applied in degrading toxic organophosphate pesticides. Full article

Acephate is an organophosphate foliar and soil insecticide that is used worldwide. In this study, the transgenerational ovarian developmental toxicity caused by acephate, along with its in utero reprogramming mechanisms, were explored. Thirty female virgin Wistar albino rats were randomly assigned to three groups: one control group and two acephate treatment groups. The treatment groups received daily low or high doses of acephate (34.2 mg/kg or 68.5 mg/kg body weight, respectively) from gestational day 6 until spontaneous labor, resulting in F1 offspring. At 28 days, a subgroup of F1 females were euthanized. The ovaries were extracted, thoroughly cleaned, and weighed before being fixed for further analysis. The remaining F1 females were mated with normal males to produce the F2 generation. The F1 female offspring presented reduced fertility and body weight, whereas the ovarian weight index and sex ratio increased in a dose-dependent manner. Structural analysis revealed altered follicular abnormalities with ovarian cells displaying pyknotic nuclei. Additionally, the gene and protein expression of Cyp19 decreased, whereas that of Gdf-9 increased in the high-dose treatment group (68.5 mg/kg). We also observed significantly increased expression levels of ovarian estrogen receptor 1 (Esr1) and insulin-like growth factor 1 (Igf1), whereas Insl3 expression was significantly decreased. The F2 female offspring presented reproductive phenotype alterations similar to those of F1 females including decreased fertility, reduced Cyp19 gene and protein expression, and structural ovarian abnormalities similar to those of polycystic ovary syndrome (PCOS). In conclusion, acephate induced ovarian developmental toxicity across two generations of rats, which may be linked to changes in the ovarian Cyp19, Gdf9, Insl3, and Igf1 levels. Full article

The white-backed planthopper (WBPH) poses a significant threat to rice crops globally. A bioassay was conducted on three WBPH populations collected from Korean rice fields to assess the effectiveness of five insecticides, including etofenprox and fenobucarb. The results showed a mortality rate of over 97% at the recommended concentration for carbamate and organophosphate insecticides. However, etofenprox exhibited a mortality rate of less than 40% in all tested populations with the Jindo population showing the highest resistance. No mutations were identified in the voltage-sensitive sodium channel, the target site of etofenprox, suggesting an alternative resistance mechanism. To explore this, RNA-seq analysis was performed on the Jindo population to identify genes potentially associated with etofenprox resistance. Gene expression was assessed after treatment with two sublethal doses of etofenprox using the Jindo population. The analysis revealed that the CYPSF gene, part of the CYP6 family, was consistently overexpressed in both treated and untreated samples. This observation aligns with the bioassay results, where mortality increased significantly after treatment with the cytochrome P450 inhibitor PBO, indicating that CYPSF may play a key role in etofenprox resistance. Additionally, distinct gene expression patterns at different etofenprox concentrations suggest that metabolic resistance mechanisms may be involved. Full article

Background: The swift expansion of the invasive malaria vector Anopheles stephensi throughout Africa presents a major challenge to malaria control initiatives. Unlike the native African vectors, An. stephensi thrives in urban settings and has developed resistance to multiple classes of insecticides, including pyrethroids, organophosphates, and carbamates. Methods: Insecticide susceptibility tests were performed on field-collected An. stephensi mosquitoes from Awash Sebac Kilo, Ethiopia, to assess insecticide resistance levels. Illumina RNA-seq analysis was then employed to compare the transcriptomes of field-resistant populations and susceptible laboratory strains (STE2). Results: An. stephensi populations exhibited high levels of resistance to both deltamethrin (mortality, 39.4 ± 6.0%) and permethrin (mortality, 59.3 ± 26.3%) in WHO tube bioassays. RNA-seq analysis revealed that both field-resistant and field-unexposed populations exhibited increased expressions of genes associated with pyrethroid resistance, including esterases, P450s, and GSTs, compared to the susceptible STE2 strain. Notably, esterase E4 and venom carboxylesterase-6 were significantly overexpressed, up to 70-fold, compared to the laboratory strain. Functional enrichment analysis revealed a significant overrepresentation of genes associated with catalytic activity under molecular functions and metabolic process under biological process. Using weighted gene co-expression network analysis (WGCNA), we identified two co-expression modules (green and blue) that included 48 genes strongly linked to pyrethroid insecticide resistance. A co-expression network was subsequently built based on the weight values within these modules. Conclusions: This study highlights the role of esterases in the pyrethroid resistance of an An. stephensi population. The identification of candidate genes associated with insecticide resistance will facilitate the development of rapid diagnostic tools to monitor resistance trends. Full article

Organophosphate neuroactive agents represent severe security threats in various scenarios, including military conflicts, terrorist activities and industrial accidents. Addressing these threats necessitates effective protective measures, with a focus on decontamination strategies. Adsorbents such as bentonite have been explored as a preliminary method for chemical warfare agent immobilization, albeit lacking chemical destruction capabilities. Chemical decontamination, on the other hand, involves converting these agents into non-toxic or less toxic forms. In this study, we investigated the hydrolytic activity of a Cu(II) complex, previously studied for phosphate ester hydrolysis, as a potential agent for chemical warfare decontamination. Specifically, we focused on a ligand featuring a thiophene anchor bound through an aliphatic spacer, which exhibited high hydrolytic activity in its Cu(II) complex form in our previous studies. Paraoxon, an efficient insecticide, was selected as a model substrate for hydrolytic studies due to its structural resemblance to specific chemical warfare agents and due to the presence of a chromogenic 4-nitrophenolate moiety. Our findings clearly show the hydrolytic activity of the studied Cu(II) complexes. Additionally, we demonstrate the immobilization of the studied complex onto a solid substrate of Amberlite XAD4 via copolymerization of its thiophene side group with dithiophene. The hydrolytic activity of the resultant material towards paraoxon was studied, indicating its potential utilization in organophosphate neuroactive agent decontamination under mild conditions and the key importance of surface adsorption of paraoxon on the polymer surface. Full article

Human arboviral diseases such as dengue, chikungunya, and Zika can be transmitted by the mosquito Aedes aegypti. The insecticide-based vector control strategy is critical in reducing transmission of these Aedes-borne diseases but is threatened mainly by the emergence of insecticide resistance. Adult Ae. aegypti from the National Capital Region (NCR), Philippines, were subjected to bioassays to determine their susceptibility to diagnostic doses of pyrethroid, organochlorine, and organophosphate insecticides following the standard World Health Organization insecticide susceptibility test. This study reports the detection of insecticide resistance to pyrethroids and organochlorine in Ae. aegypti from the Philippines for the first time. Most of the Ae. aegypti populations from NCR exhibited phenotypic resistance to permethrin, etofenprox, and DDT. Varying resistance levels to deltamethrin, cyfluthrin, and lambda-cyhalothrin were observed in the different mosquito populations, while all populations tested to malathion were susceptible to this organophosphate. This finding should alert public health authorities to consider modifying the existing vector management package for greater control efficacy. Best practices proven to prevent or delay the development of insecticide resistance, such as insecticide rotation, should also be implemented, while alternative chemicals with a different mode of action should be explored to ensure the continuing efficacy of program interventions. Full article

Organophosphates are widely used in the livestock industry. In this study, we developed a method for detecting 27 organophosphate insecticides in animal-derived foods, including beef, pork, chicken, milk, and eggs, using liquid chromatography–tandem mass spectrometry. A modified QuEChERS method was optimized for sample pretreatment. A mixture of acetonitrile and acetone was used as the extraction solvent, and MgSO₄ and NaCl were used as salts. Among the five different dispersive solid-phase extraction systems, MgSO₄, primary secondary amines, and C18 were selected for purification because they had the highest recovery rates and least matrix effects. The matrix-dependent limit of quantitation was 0.0005–0.005 mg/kg, and the correlation coefficient of the matrix-matched calibration curve was >0.99, which was acceptable for quantifying residues below 0.01 mg/kg—the default maximum residue limit in a positive list system. The recovery efficiencies ranged from 71.9 to 110.5%, with standard deviations ranging from 0.2% to 12.5%, satisfying the SANTE guidelines. The established analytical method was used to monitor organophosphates in animal-derived foods obtained from a local market, and no pesticides were detected. With respect to industry standards, our proposed method is recommended for practical organophosphate detection in animal-derived foods. Full article