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Mosquito-borne diseases, such as malaria, dengue, and Zika, pose major public health challenges globally, affecting millions of people. The growing resistance of mosquito populations to synthetic insecticides underscores the critical need for effective and environmentally friendly larvicides. Although chemical pesticides can initially be effective, they often lead to negative environmental consequences and health hazards for non-target species, including humans. This study aimed to evaluate the larvicidal effects of Trachyspermum ammi essential oil and Delphinium speciosum extract on the larvae of three major mosquito species: Aedes aegypti, Anopheles stephensi, and Culex quinquefasciatus. Mosquito larvae of Ae. aegypti, An. stephensi, and Cx. quinquefasciatus were reared under controlled laboratory conditions. The larvicidal activity of T. ammi essential oil and D. speciosum extract was evaluated through standard bioassays, using various concentrations of essential oils (10, 20, 40, 80, and 160 ppm) and extracts (160, 320, 640, 1280, and 2560 ppm) to determine the lethal concentration (LC50) values after 24 h of exposure. Fresh plant materials were collected, with the essential oil extracted via hydro-distillation, and the extract prepared using methanol solvent extraction. The chemical composition of T. ammi essential oil was examined using gas chromatography-mass spectrometry (GC-MS). Additionally, the preliminary analysis of the chemical compounds in D. speciosum extract was carried out using thin layer chromatography (TLC) and nuclear magnetic resonance spectroscopy (NMR) techniques. The results indicated that the essential oil of T. ammi exhibited more effective larvicidal activity compared to the D. speciosum extract. Specifically, the essential oil demonstrated LC50 values of 18 ppm for Cx. quinquefasciatus and 19 ppm for Ae. aegypti. In contrast, the D. speciosum extract showed the strongest larvicidal effect against An. stephensi, with an LC50 of 517 ppm. Concentrations of 40 ppm of the essential oil and 1280 ppm of the extract resulted in 100% mortality across all three species. Both the essential oil of T. ammi and the D. speciosum extract exhibited concentration-dependent larvicidal activity, and these results were statistically significant (p < 0.001) compared to the no-treatment group. GC-MS analysis revealed thymol (88.95%), o-cymen-5-ol (4.11%), and γ-terpinene (2.10%) as the major constituents of the T. ammi essential oil. Additionally, TLC verified the presence of alkaloids in both chloroform and methanolic extracts. Proton NMR identified a diterpene structure for these alkaloids. These findings suggest that T. ammi essential oil is a promising candidate for natural mosquito control strategies. Given its efficacy, further research is warranted to explore its potential in integrated vector management programs.

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Mosquitoes are considered one of the most lethal creatures on the planet and are responsible for millions of fatalities annually through the transmission of several diseases to humans. Green trash is commonly employed in agricultural fertilizer manufacturing and microbial bioprocesses for energy production. However, there is limited information available on the conversion of green waste into biocides. This study investigates the viability of utilizing green waste as a new biopesticide against Culex pipiens mosquito larvae. The current study found that plant extracts from Punica granatum (98.4 % mortality), Citrus sinensis (92 % mortality), Brassica oleracea (88 % mortality), Oryza sativa (81.6 % mortality), and Colocasia esculenta (53.6 % mortality) were very good at killing Cx. pipiens larvae 24 h post-treatment. The LC50 values were 314.43, 370.72, 465.59, 666.67, and 1798.03 ppm for P. granatum, C. sinensis, B. oleracea, O. sativa, and C. esculenta, respectively. All plant extracts, particularly P. granatum extract (14.93 and 41.87 U/g), showed a significant reduction in acid and alkaline phosphate activity. Additionally, pomegranate extract showed a significant decrease (90 %) in field larval density, with a stability of up to five days post-treatment. GC-MS results showed more chemical classes, such as terpenes, esters, fatty acids, alkanes, and phenolic compounds. HPLC analysis revealed that the analyzed extracts had a high concentration of phenolic and flavonoid components. Moreover, there are many variations among these plants in the amount of each compound. The docking interaction showed a simulation of the atomic-level interaction between a protein and a small molecule through the binding site of target proteins, explaining the most critical elements influencing the enzyme's activity or inhibitions. The study's findings showed that the various phytochemicals found in agro-waste plants had high larvicidal activity and provide a safe and efficient substitute to conventional pesticides for pest management, as well as a potential future in biotechnology.

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Lysinibacillus sphaericus is a bacterium that, along with Bacillus thuringiensis var. israelensis, is considered the best biological insecticide for controlling mosquito larvae and an eco-friendly alternative to chemical insecticides. It depends on peptidic molecules such as N-acetylglucosamine to obtain carbon sources and possesses a phosphotransferase system (PTS) for their incorporation. Some strains carry S-layer proteins, whose involvement in metal retention and larvicidal activity against disease-carrying mosquitoes has been demonstrated. Alterations in the amino sugar incorporation system could affect the protein profile and functionality. Strain ASB13052 and the isogenic mutant in the ptsH gene, which is predominant in the PTS signaling pathway, were used in this study. For the first time, the presence of N-glycosylated S-layer proteins was confirmed in both strains, with a variation in their molecular weight pattern depending on the growth phase. In the exponential phase, an S-layer protein greater than 130 kDa was found in the ptsH mutant, which was absent in the wild-type strain. The mutant strain exhibited altered and incomplete low quality sporulation processes. Hemolysis analysis, associated with larvicidal activity, showed that the ptsH mutant has higher lytic efficiency, correlating with the high molecular weight protein. The results allow us to propose the potential effects that arise as a result of the absence of amino sugar transport on hemolytic activity, S-layer isoforms, and the role of N-acetylglucosamine in larvicidal activity.

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The current research describes a phytochemical analysis and antimicrobial activity of essential oils extracted from the leaves of two Vietnamese Annonaceae species Goniothalamus yunnanensis W.T.Wang and G. touranensis Ast. By the GC-FID/MS (gas chromatography-flame ionization detection/mass spectrometry) analyses, sesquiterpene hydrocarbons accounted for the highest percentage of 68.22% in G. yunnanensis leaf essential oil with bicyclogermacrene (31.03%) and (E)-caryophyllene (21.12%) being the main compounds. G. touranensis leaf essential oil was dominated by monoterpene hydrocarbons (57.08%) with p-cymene (19.95%) and α-pinene (16.82%) being the major compounds. Two oil samples showed strong antibacterial effects on the Gram-positive bacteria Enterococcus faecalis ATCC51299, Staphylococcus aureus ATCC29213, and Bacillus cereus ATCC11778 with the MIC values of 16-64 µg/mL. They also inhibited the growth of the yeast Candida albicans ATCC 60193 with the same MIC value of 128 µg/mL. Both two oil samples showed strong mosquito larvicidal activity against four-instar larvae of Aedes aegypti and Ae. albopictus with the 24-h LC50 values of 16.75-27.60 µg/mL and 24-h LC90 values of 24.31-46.18 µg/mL. Docking results indicated that bicyclogermacrene and p-cymene exhibited the highest ΔG (binding affinity) values of -8.208 and -6.799 kcal/mol with the olfactory binding proteins (OBPs) of Ae. aegypti and Ae. albopictus, respectively.

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Mosquitoes, one of the deadliest animals on the planet, cause millions of fatalities each year by transmitting several human illnesses. Synthetic pesticides were previously used to prevent the spread of diseases by mosquitoes, which was effective in protecting humans but caused serious human health problems, environmental damage, and developed mosquito pesticide resistance. This research focuses on exploring new, more effective, safer, and environmentally friendly compounds to improve mosquito vector management. Phytochemicals are possible biological agents for controlling pests and many are target-specific, rapidly biodegradable, and eco-friendly. The potential of extracts of Lantana camara, Melia azedarach, Nerium oleander, Ricinus communis, and Withania somnifera against 3rd instar Culex pipiens (Common house mosquito) larvae was evaluated. Methanol extracts had more toxic effects against Cx. pipiens larvae (95-100%, 24 h post-treatment) than aqueous extracts (63-91%, 24 h post-treatment). The methanol extracts of Nerium oleander (LC50 = 158.92 ppm) and Ricinus communis (LC50 = 175.04 ppm) were very effective at killing mosquito larvae, 24 h after treatment. N. oleander (LC50 = 373.29 ppm) showed high efficacy in aqueous plant extracts. Among the different extracts of the five plants screened, the methanol extract of R. communis recorded the highest ovicidal activity of 5% at 800 ppm concentration. Total developmental duration and growth index were highly affected by R. communis and M. azedarach methanol extracts. In field tests it was clear that plant extracts decreased mosquito larval density, especially when mixed with mosquito Bti briquette, with stability up to seven days for N. oleander. GC-MS results showed that the methanol extract had a higher number of chemical compounds, particularly with more terpene compounds. A high-performance liquid chromatography (HPLC) technique was used to detect the existence of non-volatile polyphenols and flavonoids. All five methanol extracts showed high concentrations of active ingredients such as gallic acid, chlorogenic acid (more than 100 µg/ml) and the rosmarinic acid was also found in all the five extracts in addition to 17 active polyphenols and flavonoids presented at moderate to low concentrations. Molecular modeling of 18 active ingredients detected by the HPLC were performed to the vicinity of one of the fatty acid binding proteins of lm-FABP (PDB code: 2FLJ). Rutin, Caffeic acid, coumaric acid and rosmarinic acid which presented densely in R. communis and N. oleander showed multiple and stable intermolecular hydrogen bonding and π-π stacking interactions. The inhibition ability of the fatty acid binding protein, FABP4, was evaluated with remarkable receptor inhibition evident, especially with R. communis and N. oleander having inhibitory concentrations of IC50 = 0.425 and 0.599 µg/mL, respectively. The active phytochemical compounds in the plants suggest promising larvicidal and ovicidal activity, and have potential as a safe and effective alternative to synthetic insecticides.

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A new series of substituted benzo[h]chromene, benzochromenopyrimidine, and benzochromenotriazolopyrimidine derivatives were synthesized via chemical transformations of iminonitrile, ethoxymethylene amino, and cyanomethylene functionalities. The chemical structures of the synthesized compounds were assured by spectroscopic data and elemental analysis. The larvicidal efficacy of these compounds against Culex pipiens L. larvae was investigated, revealing potent insecticidal activity, particularly for compounds 6, 10, and 16, exceeding that of the standard insecticide chlorpyrifos. The mode of action of these compounds was explored through molecular docking studies, indicating their potential as acetylcholine esterase (AChE) inhibitors and nicotinic acetylcholine receptors (nAChR) blockers. The structure-activity relationship analysis highlighted the influence of substituents and fused heterocyclic rings on larvicidal potency. These findings suggest that the synthesized compounds hold promise as potential candidates for developing novel and effective mosquito control agents.

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Plants are a treasure trove of biological materials containing a wide range of potential phytochemicals that are target-specific, rapidly biodegradable, and environmentally friendly, with multiple medicinal effects. Unfortunately, the development of resistance to synthetic pesticides and antibiotics led to the discovery of new antibiotics, antioxidants, and biopesticides. This has also led to the creation of new medications that work very well. The current study aimed to prove that ornamental plants contain specialized active substances that are used in several biological processes. Mosquitoes, one of the deadliest animals on the planet, cause millions of fatalities each year by transmitting several human illnesses. Phytochemicals are possible biological agents for controlling pests that are harmful. The potential of leaf extracts of Bougainvillea glabra, Delonix regia, Lantana camara, and Platycladus orientalis against Culex pipiens and microbial agents was evaluated. Acetone extracts had more toxic effects against Cx. pipiens larvae (99.0-100 %, 72 h post-treatment), and the LC50 values were 142.8, 189.5, 95.4, and 71.1 ppm for B. glabra, D. regia, L. camara, and P. orientalis, respectively. Plant extracts tested in this study showed high insecticidal, antimicrobial, and antioxidant potential. GC-MS and HPLC analyses showed a higher number of terpenes, flavonoids, and phenolic compounds. The ADME analysis of element, caryophyllene oxide, caryophyllene, and copaene showed that they were similar to drugs and that they were better absorbed by the body and able to pass through the blood-brain barrier. Our results confirm the ability of ornamental plants to have promising larvicidal and antimicrobial activity and biotechnology.

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Environmental pollution, being a major concern worldwide, needs a unique and ecofriendly solution. To answer this, researchers are aiming in utilizing plant extracts for the synthesis of nanoparticles. These NPs synthesized using plant extracts provide a potential, environmentally benign technique for biological and photocatalytic applications. Especially, plant leaf extracts have been safe, inexpensive, and eco-friendly materials for the production of nanoparticles in a greener way. In this work, zinc ferrite nanoparticles (ZnFe2O4 NPs) were prepared using Nyctanthes arbor-tristis leaf extract by hydrothermal method, and its biological and photocatalytic properties were assessed. The synthesized ZnFe2O4 NPs were characterized using powder X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier-transform infrared spectroscopy (FT-IR). X-ray diffraction confirmed the arrangement of the fcc crystal structure of the nanoparticles and that some organic substances were encapsulated within the zinc ferrite. According to the SEM analysis, the resulting nanoparticles got agglomerated and spherical in shape. The ZnFe2O4 nanoparticles are in their pure form, and all of their elemental compositions were shown by the energy-dispersive X-ray analysis (EDAX) spectrum. The FTIR results revealed that the produced nanoparticles contained distinctive functional groups. Fluorescence spectroscopy was used to examine the binding affinities between bovine serum albumin (BSA) and ZnFe2O4 nanoparticles in terms of protein binding, stability, and conformation. The interaction between BSA and ZnFe2O4 NPs was examined using steady-state and time-resolved fluorescence measurements, and it was evident that static quenching occurred. The ability of ZnFe2O4 nanoparticles to kill Culex quinquefasciatus (C. quinquefasciatus) larvae was evaluated. The synthesized NPs demonstrated a noteworthy toxic effect against the fourth instar larvae of C. quinquefasciatus with LC50 values of 43.529 µg/mL and LC90 values of 276.867 µg/mL. This study revealed the toxicity of green synthesized ZnFe2O4 NPs on mosquito larvae, proving that these NPs are good and effective larvicides. Furthermore, the ZnFe2O4 NPs were utilized for dye degradation of methylene blue under visible light treatment and achieved 99.5% degradation.

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In this study, the phytochemical profile and silver nanoparticle (AgNPs)-synthesizing ability of Pittosporum undulatum methanol extract were investigated. Furthermore, biological applications of the AgNPs, such as antibacterial effect (against Klebsiella pneumoniae, Staphylococcus aureus, Bacillus subtilis, and Escherichia coli), mosquito larvicidal effect (against Anopheles stephensi, Culex quinquefasciatus, and Aedes aegypti), and cytotoxicity (against fibroblast cell line L929) were evaluated using in vitro experiments. The phytochemical analysis revealed that the methanol extract contained cardiac glycosides, terpenoids, saponins, alkaloids, flavonoids, glycosides, coumarins, phenolics, and tannins. Furthermore, standard characterization techniques such as UV-Vis spectrometry, SEM, TEM, FTIR, and XRD confirmed that the methanol extract of P. undulatum effectively synthesized the AgNPs. The synthesized AgNPs had a spherical shape and size of 20-200 nm. The bactericidal analysis revealed that the AgNPs have dose-dependent antibacterial activity. The MTT assay showed that the AgNPs were bio-compatible up to a dosage of 250 µg mL-1 in the normal fibroblast cell line L929. Furthermore, the LC50 values for AgNPs against larvae of An. stephensi, Cx. quinquefasciatus, and Ae. aegypti were 0.4, 4.7, and 1.2 ppm, respectively. Field trials demonstrated that the larvicidal effect was enhanced within 24-72 h, and the rate of reduction increased over time. Thus, our findings provide an ideal sustainable AgNP bio-pesticide to combat filarial, dengue, and malaria vectors.

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As there has been no scientific evidence of the bioactivity of Sambucus ebulus (Adoxaceae) extracts against insects, we chemically characterized S. ebulus leaves and flowers extracted in methanol and water. The crude extracts, phenolic compounds, and amino acids isolated were tested as larvicides against the fourth-instar larvae of Aedes albopictus and Culex pipiens (Diptera: Culicidae). To understand their mode of action, we evaluated the in vitro acetylcholinesterase (AChE) inhibitor effect of the crude extracts on the two mosquito larvae through a colorimetric method. Furthermore, the deterrent effect of the crude extracts against ovipositing Ae. albopictus females was assessed in the open field. Twelve phenylpropanoids and fourteen amino acids were detected in the extracts, with a prevalence of hydroxycinnamic acids and nonaromatic amino acids. The most toxic compound to Ae. albopictus larvae after 24 h was gallic acid, followed by the crude S. ebulus leaf extract; on Cx. pipiens, it was the crude flower extract. The AChE test showed higher inhibition on both mosquito species exerted by the leaf extract if compared to the flower extract, and it also deterred oviposition by Ae. albopictus females starting from the third day. The results indicated that vegetal extracts could effectively help in the integrated vector management of mosquitoes.

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Nematophagous fungi (NF) form part of the soil microbiota and are natural enemies of nematodes, helping to regulate nematode populations. A verticillate NF isolated from soil from Tepalcingo, Mexico, was morphologically and molecularly characterised. This fungus was cultured in two different liquid media-Czapek-Dox broth (CzDoxB) and sweet potato dextrose broth (SPDB)-for 21 days. The ovicidal (OA) and larvicidal (LA) activities of fungal liquid culture filtrates (LCFs) were assessed in 96-well microtitre plates at different concentrations against Haemonchus contortus after 48 h. The morphological and molecular identification revealed the presence of Lecanicillium psalliotae. Additionally, the groups of compounds associated with nematocidal activity were determined from a qualitative chemical profile (QCP) using different reagents. The highest OA of the LCFs was obtained at 25 mg/mL from SPDB and CzDoxB and amounted to 97.2 and 99.06%, respectively. Meanwhile, the highest LA recorded with these LCFs at 100 mg/mL was 54.27% and 96.8%, respectively. The QCP revealed the presence of alkaloids and tannins in both LCFs that have previously been associated with nematocidal activity. Lecanicillium psalliotae exerted an important effect on H. contortus and could be of significance in future studies focused on the control and prevention of haemonchosis in small ruminants.

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In this study, essential oils and waste hydrosols of leaves of Ocimum tenuiflorum in four different geographical locations were extracted by hydrodistillation method and using gas chromatography / mass spectrometry (GC/MS) for chemical composition analysis. All four essential oil samples contained the main components (E)-ß-caryophyllene (27.8-49.0%), trans-ß-elemene (20.3-37.1%) and eugenol (9.0-44.0%). Three of the four hydrosol samples had eugenol in absolute content (94.5-98.6%), while the remaining hydrosol sample had two main components, elemicin (77.8%) and eugenol (14.2%). Essential oils and hydrosols demonstrated larvicidal activities against four important disease-transmitting mosquito species including Aedes aegypti, Aedes albopictus, Culex quinquefasciatus, and Culex fuscocephala with 24-h LC50 values in the range 15.42-56.01 µg/mL and 53.88-97.80 µg/mL for the essential oils and the hydrosols, respectively. Essential oils and hydrosols strongly inhibited the acetylcholinesterase (AChE) enzyme of electric eels with IC50 values in the range of 25.35-107.19 µg/mL. Microemulsion (ME) can be considered as a sustainable pesticide formulation over 300 days and has improved larvicidal activity compared to free essential oil. The O. tenuiflorum in Vietnam can be considered a low-cost source of eugenol, botanical pesticides that control disease-transmitting mosquitoes, as well as having therapeutic potential to be further investigated.

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Herein, we focused on the larvicidal effects and potential mechanisms of 5-ethenyl-2,2'-bithiophene (5 EB), a compound isolated from Echinops ritro L. on Aedes aegypti larvae. Our results show that 5 EB exhibits pronounced larvicidal activity against A. aegypti larvae, with an LC50 = 0.24 mg/L, considerably lesser than that of the traditional insecticide, rotenone. Observations using fluorescence microscopy, electron microscopy, and imaging flow cytometry demonstrated that 5 EB targets the hemocytes of larvae, leading to the disruption of their intracellular membrane systems. This disruption leads to considerable damage to the cellular structure and function, leading to the death of test subjects. Note that additional investigation into the molecular mechanism of 5 EB's action was conducted using transcriptomic analysis. Both GO and KEGG enrichment analyses reported that the differentially expressed genes were predominantly associated with membranes, lysosomes, and catalytic activities. To summarize, this study provides new options for developing new, environmentally friendly, plant-based larvicides for mosquito control.

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The tropical climate in Malaysia provides an ideal environment for the rapid proliferation of Aedes mosquitoes, notably Aedes aegypti and Aedes albopictus, prominent vectors of dengue fever. Alarmingly, these species are increasingly developing resistance to conventional pesticides. This study aimed to evaluate the efficacy of Metarhizium anisopliae isolate HSAH5 spores, specifically on conidia (CO) and blastospores (BL), against Ae. albopictus larvae. The study centered on evaluating their pathogenic effects and the resultant changes in protein expression. Spore suspensions with varying concentrations were prepared for larvicidal bioassays, and protein expressions were analysed using liquid chromatography-mass spectrometry. Subsequently, protein annotation and network analysis were conducted to elucidate infection mechanisms and the proteomic response. Based on the lethal concentrations and time frames, CO exhibited faster larval mortality than BL at lower concentrations. Despite this, both spore types demonstrated comparable overall pathogenic effects. Results from the proteomic profiling revealed 150 proteins with varied expressions following exposure to Ae. albopictus extract, shedding light on distinct infection strategies between the spores. Gene Ontology enrichment and network analysis illustrated the diverse metabolic adaptations of M. anisopliae and interactions with mosquito larvae. This highlighted the complexity of host-pathogen dynamics and the significance of biosynthetic processes, energy storage, and cellular interaction pathways in disease progression. The BL network, consisting 80 proteins and 74 connections, demonstrates the intricate fungal mechanisms triggered by host stimuli. Conversely, the CO network, though smaller, displayed notable interconnectivity and concentrated involvement at the cell periphery, suggesting a deliberate strategy for initial host contact. This study offers valuable insights into proteome dynamics of M. anisopliae's BL and CO for managing mosquito populations and combating disease transmission, thereby significantly advancing public health and environmental conservation efforts.

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Plants contain a wide range of potential phytochemicals that are target-specific, and less toxic to human health. The present study aims to investigate the metabolomic profile of Nephrolepis exaltata (L.) Schott and its potential for mosquito control by targeting Glutathione-S-Transferase, focusing on the larvicidal activity against Culex pipiens. Crude extracts (CEs) were prepared using ethanol, ethyl acetate and n-hexane. CEs have been used for assessment of mosquitocidal bioassay. The metabolomic analyses for CEs were characterized for each CE by gas chromatography-mass spectrometry (GC-MS). The most efficient CE with the highest larval mortality and the least LC50 was the hexane CE. Then, alkaline phosphatase (ALP) activity, and glutathione-S-transferase (GST) activity were assessed in larvae treated with the hexane CE. The results demonstrated a decline in protein content, induction of ALP activity, and reduction in GST activity. Finally, molecular docking and dynamic simulation techniques were employed to evaluate the interaction between the hexane phytochemicals and the GST protein. D-(+)-Glucuronic acid, 3TMS derivative and Sebacic acid, 2TMS derivative showed best binding affinities to GST protein pointing to their interference with the enzyme detoxification functions, potentially leading to reduced ability to metabolize insecticides.

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Biosynthetic metals have attracted global attention because of their safety, affordability, and environmental friendliness. As a consequence, the cell-free filtrate (CFF) of Dill leaf-derived endophytic fungus Aspergillus luchuensis was employed for the extracellularly synthesis silver nanoparticles (AgNPs). A reddish-brown color shift confirmed that AgNPs were successfully produced. The obtained AgNPs were characterized by UV-Vis (ultraviolet-visible spectroscopy), Transmission electron microscopy (TEM), FTIR, EDX, and zeta potential. Results demonstrated the creation of crystalline AgNPs with a spherical shape at 427.81 nm in the UV-Vis spectrum, and size ranged from 16 to 18 nm as observed by TEM. Additionally, the biogenic AgNPs had a promising antibacterial activity versus multidrug-resistant bacteria, notably, S. aureus, E. coli, and S. typhi. The highest growth reduction was recorded in the case of E. coli. Furthermore, the biosynthesized AgNPs demonstrated potent antifungal potential versus a variety of harmful fungi. The maximum growth inhibition was evaluated from A. brasinsilles, followed by C. albicans as compared to cell-free extract and AgNO3. In addition, data revealed that AgNPs possess powerful antioxidant activity, and their ability to scavenge radicals increased from 33.0 to 85.1% with an increment in their concentration from 3.9 to 1,000 µg/mL. Furthermore, data showed that AgNPs displayed high catalytic activity of safranin under light irradiation. The maximum decolorization percentage (100%) was observed after 6 h. Besides, the biosynthesized AgNPs showed high insecticidal potential against 3rd larval instar of Culex pipiens. Taken together, data suggested that endophytic fungus, A. luchuensis, is an attractive candidate as an environmentally sustainable and friendly fungal nanofactory.

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The study explored Simarouba glauca DC. for mosquito larvicidal potential by performing bioactivity-guided chemical investigation of its root extract resulting in isolation of the known bioactive metabolite glaucarubinone (1). Mosquito larvicidal activity of glaucarubinone (1) against the three vector species viz. Anopheles stephensi, Aedes aegypti, and Culex quinquefasciatus was determined using a modified WHO 2005 protocol. It was observed that Culex quinquefasciatus larvae were the most susceptible species with LC50 13.88 ppm and LC90 70.01 ppm followed by Aedes aegypti and Anopheles stephensi at 24 h of exposure. The mode of action as observed microscopically is the lysis of midgut and thorax cells of the third instar larvae. The crystal structure of the glaucarubinone (1) is reported for the first time using X-ray crystallography. This phytochemical product has the potential to act as a green alternative to existing chemical-based insecticides for integrated vector management.

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This study investigates the chemical composition of the essential oil obtained from the leaves of Bocageopsis multiflora (Mart.) R.E.Fr (Annonaceae), examining its effectiveness in combating both the larvae and adult forms of Aedes aegypti mosquitoes. Additionally, for a deeper understanding of the insecticidal activity, toxicity properties and molecular docking calculations were conducted using the main compounds of this essential oil. GC/MS analysis revealed the presence of 26 constituents, representing 95.2% of the essential oil, with the major components identified as the sesquiterpenes α-selinene, ß-selinene, and ß-elemene. Larvicidal assays demonstrated potent activity of this essential oil with significant LC50 values of 40.8 and 39.4 µg/mL at 24 and 48 h, respectively. Adulticidal assessments highlighted strong efficacy with LC50 of 12.5 µg/mL. Molecular docking analysis identified optimal interaction activities of α-selinene and ß-selinene with key Aedes proteins. The in silico studies comparing synthetic insecticides with the major sesquiterpenes of the essential oil revealed that ß-selinene exhibited a significantly higher binding affinity compared to the other two sesquiterpenes. Also, ADMET studies of the three main sesquiterpenes indicated acceptable drug-like properties. In these findings, safety evaluations showed low toxicity and skin sensitization for the main sesquiterpenes, contrasting with commercial synthetic insecticides. Therefore, in silico analyses suggest promising interactions with Aedes proteins, indicating its potential as an effective alternative to conventional insecticides These results show the larvicidal and adulticidal potential of the essential oil from Bocageopsis multiflora against Aedes aegypti, supported by its predominant constituents, α-selinene, ß-selinene and ß-elemene.

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Mosquito-borne disease pandemics, such as the Zika virus and chikungunya, have escalated cognizance of how critical it is to implement proficient mosquito vector control measures. The prevention of Culicidae is becoming more difficult these days because of the expeditious imminence of synthetic pesticide resistance and the universal expansion of tremendously invasive mosquito vectors. The present study highlights the insecticidal and larvicidal efficacy of the prospective novel actinobacterium derived from the marine Streptomyces sp. RD06 secondary metabolites against Culex quinquefasciatus mosquito. The pupicidal activity of Streptomyces sp. RD06 showed LC50=199.22 ± 11.54 and LC90= 591.84 ± 55.41 against the pupa. The purified bioactive metabolites 1, 2-Benzenedicarboxylic acid, diheptyl ester from Streptomyces sp. RD06 exhibited an LC50 value of 154.13 ± 10.50 and an LC90 value of 642.84 ± 74.61 tested against Cx. quinquefasciatus larvae. The Streptomyces sp. RD06 secondary metabolites exhibited 100 % non-hatchability at 62.5 ppm, and 82 % of hatchability was observed at 250 ppm. In addition, media optimization showed that the highest biomass production was attained at a temperature of 41.44 °C, pH 9.23, nitrogen source 11.43 mg/ml, and carbon source 150 mg/ml. Compared to control larvae, the histology and confocal microscopy results showed destruction to the anal gill, lumen content, and epithelial layer residues in the treated larvae. Utilizing an eco-friendly method, these alternative inventive insecticidal derivatives from Streptomyces sp. RD06 eradicates Culex quinquefasciatus. This study highlights the promising potential of these Streptomyces sp. RD06 secondary metabolites to develop affordable and efficacious mosquito larvicides to replace synthetic insecticides in the future.

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The Aedes aegypti mosquito is a vector for various arboviruses, including dengue and yellow fever. Insecticides, such as pyrethroids and organophosphates, are widely used to manage and control these insects. However, mosquitoes have developed resistance to these chemicals. Therefore, this study aimed to investigate the effects of the commercial formulation of fipronil (Tuit® Florestal; 80% purity) on the survival, behavior, morphology, and proteins related to signaling pathways of the midgut in A. aegypti larvae under controlled laboratory conditions. Significant reductions in immature survival were observed in all concentrations of fipronil tested. Low insecticide concentration (0.5 ppb) led to decreased locomotor activity in the larvae and caused disorganization of the epithelial tissue in the midgut. Moreover, exposure to the insecticide decreased the activity of detoxifying enzymes such as catalase, superoxide dismutase, and glutathione-S-transferase. On the other hand, the insecticide increased protein oxidation and nitric oxide levels. The detection of LC3, caspase-3, and JNK proteins, related to autophagy and apoptosis, increased after exposure. However, there was a decrease in the positive cells for ERK 1/2. Furthermore, the treatment with fipronil decreased the number of positive cells for the proteins FMRF, Prospero, PH3, Wg, Armadillo, Notch, and Delta, which are related to cell proliferation and differentiation. These findings demonstrate that even at low concentrations, fipronil exerts larvicidal effects on A. aegypti by affecting behavior and enzymatic detoxification, inducing protein oxidation, free radical generation, midgut damage and cell death, and inhibiting cell proliferation and differentiation. Thus, this insecticide may represent a viable alternative for controlling the spread of this vector.

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