Culex Quinquefasciatus Larvae Research Articles

Sesquiterpene Hydrocarbon-rich Essential Oil from Teucrium viscidum Blume and its Antimicrobial and Mosquito Larvicidal Activities

Objectives This study aimed to investigate the essential oil extracted from the aerial parts of Teucrium viscidum Blume, a perennial herb belonging to the Lamiaceae family, collected in Vietnam. The focus was on determining the essential oil's chemical composition and evaluating its antimicrobial and mosquito larvicidal activities. Methods The essential oil of T. viscidum was analyzed using GC–FID/MS to identify its chemical constituents. The antimicrobial activity was assessed against seven microorganisms using the broth microdilution method to determine minimum inhibitory concentration (MIC) and half-maximal inhibitory concentration (IC50) values. The larvicidal activity was evaluated against Culex quinquefasciatus larvae, with lethal concentration (LC50 and LC90) values calculated after 24 and 48 h of exposure. Results Chemical analysis revealed that the essential oil of T. viscidum was predominantly composed of sesquiterpene hydrocarbons, with ( E)-caryophyllene (47.91%) and germacrene D (19.17%) as the major constituents. The essential oil exhibited significant antimicrobial activity against three Gram-positive bacteria ( Enterococcus faecalis, Staphylococcus aureus, and Bacillus cereus), one Gram-negative bacterium ( Pseudomonas aeruginosa), and one yeast ( Candida albicans), with MIC values ranging from 32 to 64 μg/mL and IC50 values ranging from 9.56 to 24.07 μg/mL. The mosquito larvicidal activity of the essential oil showed strong efficacy against C. quinquefasciatus larvae, with LC50 values of 23.07 μg/mL after 24 h and 19.67 μg/mL after 48 h, and LC90 values of 32.90 μg/mL at 24 h and 29.99 μg/mL at 48 h, indicating increased effectiveness with prolonged exposure. Conclusion This study provides a comprehensive analysis of the chemical composition and biological activities of T. viscidum essential oil. The findings highlight its potent antimicrobial and mosquito larvicidal properties, suggesting it as a promising natural alternative to synthetic antimicrobial agents and insecticides. Further research is warranted to explore its mechanisms of action and potential applications in pharmaceuticals and pest control.

Eco-friendly synthesis of silver nanoparticles using Phyllanthus niruri leaf extract: Assessment of antimicrobial activity, effectiveness on tropical neglected mosquito vector control, and biocompatibility using a fibroblast cell line model

Abstract Mosquitoes are rapidly advancing as vectors of several severe diseases. The increasing resistance of mosquitoes and the environmental harm caused by insecticides pose significant challenges for eradicating mosquito vectors. In this study, 18 plant extracts were tested for larvicidal properties against Aedes aegypti, Culex quinquefasciatus, and Anopheles stephensi larvae. Phyllanthus niruri (Pn) showed enhanced larvicidal activity in both laboratory and field trials. The biosynthesis of silver nanoparticles (AgNPs) using Pn leaf methanol extract (Pn-LME) was confirmed by UV-visible spectroscopy, X-ray diffraction, transmission electron microscopy, scanning electron microscopy, and Fourier-transform infrared spectroscopy. Among various concentrations, 3 mM AgNPs exhibited significant LC90 values of 0.83, 1.46, and 9.11 ppm compared to 9.25, 93.48, and 14.60 ppm of Pn-LME against A. stephensi, C. quinquefasciatus, and A. aegypti, respectively. This indicates the high mortality of mosquito vectors at low AgNP concentrations. Additionally, Pn-AgNPs showed enhanced antibacterial activity and no cytotoxicity in normal fibroblast cells (L929). Field trials demonstrated a 98.70% decrease in mosquito larval density at A. stephensi breeding sites, a 96.55% reduction at C. quinquefasciatus sites, and a 97.85% reduction at Ae. aegypti sites. This study presents an eco-friendly and cost-effective AgNP bio-pesticide synthesized from Pn leaves for controlling and preventing the transmission of filarial, dengue, and malaria vectors.

Green synthesis of zinc ferrite nanoparticles from Nyctanthes arbor-tristis: unveiling larvicidal potential, protein binding affinity and photocatalytic activities.

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 43.529µg/mL and LC90 values of 276.867µg/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.

Glaucarubinone from Simarouba glauca DC. as a potential biocontrol agent for mosquito vector management

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.

Biocidal efficacy of olefinic N-alkylamides against Aedes aegypti and Culex quinquefasciatus larvae

Mosquito-borne diseases are a major public-health concern worldwide. The development of resistance in mosquitoes to the existing larvicides and the associated-risks necessitates the exploration of novel molecules to control vector-borne pathogens. This study demonstrates that N-alkylamides [2E,4E-N-isobutyl-undeca-2,4-diene-8,10-diynamide (1) and 2E,4E,8Z,10E-N-isobutyl-dodeca-2,4,8,10-tetraenamide (2)] of Acmella ciliata exhibit biocidal action against Aedes aegypti and Culex quinquefasciatus larvae. The LC50 for 1 and 2 were 44.19 and 18.28 ppm against Aedes larvae, and 30.89 and 11.75 ppm against Culex larvae, respectively. We further observed that the chain length, degree of unsaturation, and terminal methylation influence the larvicidal efficacy of N-alkylamides. HPLC-assisted quantification revealed that the content of both 1 (19.01 mg/g) and 2 (68.55 mg/g) was maximum in the flowers of A. ciliata. Thus, this study concludes that N-alkylamides are promising alternatives to control mosquito larvae and can be used as standard for quantitation in test samples.

Potential efficacy of bimetallic nanoparticles synthesized from extracellular cell-free extract of Penicillium citrinum against Culex quinquefasciatus mosquito larvae, and their photocatalytic activity

The biological synthesis of nanoparticles finds application in the development of novel insecticides and bioremediation agents. In this study, bimetallic nanoparticles were synthesized using copper and zinc salts along with Penicillium citrinum secondary metabolite. The synthesized nanoparticles were analyzed for their insecticidal and photocatalytic efficacy on Culex quinquefasciatus larvae and organic dyes, respectively. The synthesized nanoparticles were characterized by UV spectroscopy, FTIR, XRD, SEM, EDX, and HR-TEM. The results showed fungal metabolite synthesized bimetallic nanoparticles were too toxic for Culex quinquefasciatus larvae, with LC50 and LC90 values of 1016.51 ppm, 4948.12 ppm for 24 h exposure; 184.80 ppm, 718.16 ppm for 48 h exposure, and 59.07 and 338.76 ppm for 72 h exposure, respectively. The Cu–Zn bimetallic nanoparticles showed mild photocatalytic activity on Xylenol orange (36%). This study shows that bimetallic NPs synthesized from Penicillium citrinum are advantageous for mosquito control as well as having photocatalytic dye degradation properties.

Essential oil and fenchone extracted from Tetradenia riparia (Hochstetter.) Codd (Lamiaceae) induce oxidative stress in Culex quinquefasciatus larvae (Diptera: Culicidae) without causing lethal effects on non-target animals.

We investigated the larvicidal activity of the essential oil (EO) from Tetradenia riparia and its majority compound fenchone for controlling Culex quinquefasciatus larvae, focusing on reactive oxygen and nitrogen species (RONS), catalase (CAT), glutathione S-transferase (GST), acetylcholinesterase (AChE) activities, and total thiol content as oxidative stress indicators. Moreover, the lethal effect of EO and fenchone was evaluated against Anisops bouvieri, Diplonychus indicus, Danio rerio, and Paracheirodon axelrodi. The EO and fenchone (5 to 25µg/mL) showed larvicidal activity (LC50 from 16.05 to 18.94µg/mL), followed by an overproduction of RONS, and changes in the activity of CAT, GST, AChE, and total thiol content. The Kaplan-Meier followed by Log-rank (Mantel-Cox) analyses showed a 100% survival rate for A. bouvieri, D. indicus, D. rerio, and P. axelrodi when exposed to EO and fenchone (262.6 and 302.60µg/mL), while α-cypermethrin (0.25µg/mL) was extremely toxic to these non-target animals, causing 100% of death. These findings emphasize that the EO from T. riparia and fenchone serve as suitable larvicides for controlling C. quinquefasciatus larvae, without imposing lethal effects on the non-target animals investigated.

Bioactive components in Psidium guajava extracts elicit biotoxic attributes and distinct antioxidant enzyme modulation in the larvae of vectors of lymphatic filariasis and dengue

Control of mosquito vectors, which have caused a global disease burden, has employed various methods. However, the challenges posed by current physical and chemical methods have raised concerns about vector control programs, leading to the search for alternative methods that are less toxic, eco-friendly, and cost-effective. This study investigated the larvicidal potential of aqueous, methanol, and ethylacetate extracts of Guava (Psidium guajava) against Aedes aegypti and Culex quinquefasciatus larvae. Functional group and phytochemical characterization were performed using Fourier-Transform Infrared Spectroscopy (FTIR) and GC-MS analysis to identify the bioactive compounds in the extracts. Larval bioassays were conducted using WHO standard procedures at concentrations of 12.5, 25, 50, 125, and 250 mg/L, and mortality was recorded after 24, 48, and 72 h. Additionally, antioxidant enzyme profiles in the larvae were studied. All of the solvent extracts showed larvicidal activity, with the methanol extract exhibiting the highest mortality against Ae. aegypti and Cx. quinquefasciatus larvae, followed by aqueous and ethylacetate extracts. FTIR spectroscopic analysis revealed the presence of OH, C–H of methyl and methylene, CO and CC. The GC-MS analysis indicated that the methanol, aqueous, and ethylacetate extracts all had 27, 34, and 43 phytoactive compounds that were effective at causing larvicidal effects, respectively. Different concentrations of each extract significantly modulated the levels of superoxide dismutase, catalase, glutathione peroxidase, and reduced glutathione in larvae. This study's findings indicate the potential for developing environmentally friendly vector control products using the bioactive components of extracts from P. guajava leaves.

Terrestrial subsidies and light affect an aquatic micro‐ecosystem in unexpected ways

Abstract The effects of resource subsidies on a recipient ecosystem depends on a variety of factors. Firstly, increasing the supply of limiting nutrients tends to increase the accumulation of biomass across different compartments of the recipient food web. Secondly, in the case of aquatic microorganisms, this accumulation may also be contingent on inputs of energy through light, mediating interactions between heterotrophic bacteria and autotrophic algae. Thirdly, macroscopic consumers feed upon microorganisms and recycle nutrients through excretion and egestion, profoundly affecting nutrient cycling. In order to examine the context‐dependency of nutrient cycling in aquatic systems, we performed an experiment in mesocosms where we followed the responses of dissolved nutrients, microorganisms, and larvae of the cosmopolitan mosquito Culex quinquefasciatus (Diptera: Culicidae) to two terrestrial subsidies differing in carbon (C):nutrient, in combination with two light intensities. We found that the interactions amongst bacteria and algae themselves remained generally unimportant after accounting for treatment effects, and that light did mediate some of the effects of nutrient subsidies on microorganisms. We also found that the presence of mosquito larvae was associated with altered concentrations of nitrogen (N) in some treatments, ultimately benefitting algae. Finally, we found that low C:nutrient subsidies generally increased the development rate of mosquito larvae, and that increased light exposure led to higher mosquito survival. Overall, these patterns may be explained by strong nitrogen limitation in our system, causing both group of microorganisms to respond similarly to variations in nutrient supply without direct covariation, and to the key role of N recycling by mosquito larvae in sustaining algal densities in exposed treatments. The context‐dependency in our study may reflect elemental or molecular constraints other than phosphorus. Our experiment thus calls for greater synthesis amongst ecological theories.

Elytrigia Repens Extracts Control Urban Mosquito Vectors with a Larvicidal Potential

There is over 17% of global illnesses due to Vector-borne diseases and more than a million fatalities annually found as a significant public health challenge globally. Traditional methods of mosquito control are relied heavily on chemical insecticides, and led to ecological disruptions, pesticide resistance, and adverse effects on human health and the environment. Consequently, there is a persistent need for alternative and eco-friendly strategies mosquito control. Method: In this study, we investigated the efficacy of extracts from Eragrostis repens (E. repens) against the larvae of Aedes aegypti, Anopheles stephensi, and Culex quinquefasciatus. Plant extracts were prepared using different solvents, and their phytochemical profiles were analyzed. The larvicidal activity of these extracts was evaluated through susceptibility tests over a 24-hour period. Results: Methanol extracts exhibited significant larvicidal activity against Aedes aegypti, Anopheles stephensi, and Culex quinquefasciatus, with LC50 values ranging from 43,173 ppm to 58,234 ppm. GC-MS analysis identified 11 bioactive compounds in methanol extracts, highlighting their potential insecticidal activity. Conclusion: Our findings suggest that E. repens holds promise as a natural larvicide against mosquito vectors. The study highlights the importance of exploring botanical alternatives for mosquito control, offering a sustainable and environmentally friendly approach to combatting mosquito-borne diseases.

Biolarvicide activity of extract and essential oil of culantro (Eryngium foetidum L.) on Culex quinquefasciatus larvae in silico and in vitro


 
 
 
 Background: Filariasis, a priority tropical disease in Indonesia, is transmitted by the Culex quinquefasciatus mosquito. The use of conventional synthetic larvicides can lead to environmental and health issues, including poisoning and resistance in target insect populations.
 Objective: This study explores the utilization of biolarvicides derived from culantro (Eryngium foetidum) to mitigate these adverse efects, focusing on analyzing the components and evaluating the larvicidal eficacy of both the extract and essential oil of E. foetidum.
 Method: This study employed a molecular docking approach to examine in silico biolarvicidal activity against the odorant binding protein (OBP) receptor and conducted in vitro experiments on Cx. quinquefasciatus larvae using varying concentrations of E. foetidum extract (100, 250, and 500 ppm) and essential oil (10, 50, and 100 ppm).
 Results: The in silico study identified hynokiflavone and longifenaldehyde as the compounds with the most potent activity, demonstrating binding a inities of -10.2 and -9.5 kcal/mol, respectively. The in vitro assays revealed that the E. foetidum extract achieved 75% larval mortality at an LC50 of 78.59 ppm, while the essential oil resulted in 88% mortality with an LC50 of 10.13 ppm.
 Conclusion:The extract and essential oil of E. foetidum exhibit significant biolarvicidal activity against Culex quinquefasciatus, offering promising plant-based alternatives to traditional larvicides, with implications for safer and more sustainable vector control strategies.
 
 
 

Isolation of Mosquitocidal Bacteria from Soil Samples to Control Mosquito Vectors

In the present study, an attempt was made to screen and isolate potent and ecofriendly mosquitocidal bacteria from different soils collected from Union Territory of Puducherry, India. From a total of 140 soil samples, 16 isolates showed mosquitocidal activity. Out of these 16 isolates, two bacteria isolated from red soil of Kalapet and Kanagachettikulam villages of Union Territory of Puducherry, India with code no. PYKAL-31A and PYKC-33C were found to be most potent. Extensive bioassay was carried out with these two bacterial strains against larvae of Anopheles stephensi, Aedes aegypti and Culex quinquefasciatus. The LC50 and LC90 values of PYKAL-31A against Aedes aegypti, Culex quinquefasciatus and Anopheles stephensi were 0.007, 0.011, 0.015 and 0.015, 0.021 and 0.029, respectively and that of PYKC-33C were 0.009, 0.014, 0.013 and 0.015, 0.026, 0.023, respectively.

Characterization of silver sulfide nanoparticles from actinobacterial strain (M10A62) and its toxicity against lepidopteran and dipterans insect species

Abstract In this research, cell-free extracts from magnesite mine-isolated actinobacterial strain (M10A62) were used to produce silver sulfide nanoparticles (Ag2SNPs). Streptomyces minutiscleroticus JX905302, actinobacteria capable of producing Ag2SNPs, was used to synthesize Ag2NPs. The UV–vis range was used to confirm the biosynthesized Ag2NPs; Fourier transform infrared spectroscopy (FT-IR), atomic force microscopy (AFM), transmission electron microscopy (TEM), X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDAX), and dynamic light scattering analysis were employed to characterize them further. Surface resonance plasma (SRP) for Ag2SNPs was obtained at 355 nm using UV–visible spectroscopy; FT-IR detected bimolecular and eventually microbial-reduced Ag2SNPs from S. minutiscleroticus culture extract. Furthermore, AFM and TEM analysis confirms that the synthesized Ag2SNPs were spherical in shape. Dynamic light scattering revealed a negatively charged Ag2NPs surface with a diameter of 10 nm. The XRD spectrum showed the crystalline nature of the obtained particles. EDAX revealed a pure crystalline nature, and a significant silver particle signal confirms the presence of metallic silver and sulfide nanoparticles together with the signals of Cu and C atoms. After 40 and 48 h of treatment at 150–200 µg·ml−1, Ag2SNPs produced the highest mortality in Spodoptera litura, H. armigera, Aedes aegypti, and Culex quinquefasciatus larvae. Hence, the biosynthesized Ag2SNPs may be useful for potential pest control in integrated pest management and vector control program as a safer, cost-effective, selective, and environmentally friendly approaches.

Demonstration of RNAi Yeast Insecticide Activity in Semi-Field Larvicide and Attractive Targeted Sugar Bait Trials Conducted on Aedes and Culex Mosquitoes.

Eco-friendly new mosquito control innovations are critical for the ongoing success of global mosquito control programs. In this study, Sh.463_56.10R, a robust RNA interference (RNAi) yeast insecticide strain that is suitable for scaled fermentation, was evaluated under semi-field conditions. Inactivated and dried Sh.463_56.10R yeast induced significant mortality of field strain Aedes aegypti, Aedes albopictus, and Culex quinquefasciatus larvae in semi-field larvicide trials conducted outdoors in St. Augustine, Trinidad, where 100% of the larvae were dead within 24 h. The yeast was also stably suspended in commercial bait and deployed as an active ingredient in miniature attractive targeted sugar bait (ATSB) station sachets. The yeast ATSB induced high levels of Aedes and Culex mosquito morbidity in semi-field trials conducted in Trinidad, West Indies, as well as in Bangkok, Thailand, in which the consumption of the yeast resulted in adult female mosquito death within 48 h, faster than what was observed in laboratory trials. These findings support the pursuit of large-scale field trials to further evaluate the Sh.463_56.10R insecticide, a member of a promising new class of species-specific RNAi insecticides that could help combat insecticide resistance and support effective mosquito control programs worldwide.

Copper Oxide Nanoparticles Synthesized from Indigofera linnaei Ali and This Plant’s Biological Applications

The leaf extract of Indigofera linnaei Ali, an Indian medicinal plant, was utilized in the synthesis of copper oxide nanoparticles (CuO-NPs). Green chemistry is a safe and cost-effective method for the synthesis of nanoparticles using plant extracts. The synthesis of CuO NPs was confirmed using ultraviolet–visible (UV-visible) spectrum λ-max data with two peaks at 269 and 337 nm. Different functional groups were identified using Fourier-transform infrared spectroscopy (FT-IR). X-ray diffraction (XRD) was used to confirm the crystalline structure of the CuO-nanoparticles. Scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) analyses were performed to examine the surface morphology and elemental composition of the biosynthesized CuO-NPs. Furthermore, the synthesized CuO-NPs exhibited antibacterial activity against Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, and Enterococcus faecalis. Additionally, they exhibited a good insecticidal effect on Culex quinquefasciatus larvae, with low LC50 55.716 µg/mL and LC90 123.657 µg/mL values. The CuO-NPs inhibited human breast cancer cells in a concentration-dependent manner, with an IC50 value of 63.13 µg/mL.

Biogenic Synthesis of Zinc Oxide Nanoparticles Mediated by the Extract of Terminalia catappa Fruit Pericarp and Its Multifaceted Applications.

Zinc oxide nanoparticles (ZnO-NPs) were biosynthesized by using the pericarp aqueous extract from Terminalia catappa Linn. These NPs were characterized using various analytical techniques such as X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, ultraviolet (UV) spectroscopy, dynamic light scattering (DLS), and scanning electron microscopy (SEM), and XRD studies of the nanoparticles reported mean size as 12.58 nm nanocrystals with highest purity. Further SEM analysis emphasized the nanoparticles to be spherical in shape. The functional groups responsible for capping and stabilizing the NPs were identified with FTIR studies. DLS studies of the synthesized NPs reported ζ potential as -10.1 mV and exhibited stable colloidal solution. These characterized ZnO-NPs were evaluated for various biological applications such as antibacterial, antifungal, antioxidant, genotoxic, biocompatibility, and larvicidal studies. To explore its multidimensional application in the field of medicine. NPs reported a potential antimicrobial activity at a concentration of 200 μg/mL against bacterial strains in the decreasing order of Streptococcus pyogenes > Streptococcus aureus > Streptococcus typhi > Streptococcus aeruginosa and against the fungi Candida albicans. In vitro studies of RBC hemolysis with varying concentrations of NPs confirm their biocompatibility with IC50 value of 211.4 μg/mL. The synthesized NPs' DPPH free radical scavenging activity was examined to extend their antioxidant applications. The antiproliferation and genetic toxicity were studied with meristematic cells of Allium cepa reported with mitotic index (MI index) of 1.2% at the concentration of 1000 μg/mL. NPs exhibited excellent Larvicidal activity against Culex quinquefasciatus larvae with the highest mortality rate as 98% at 4 mg/L. Our findings elicit the therapeutic potentials of the synthesized zinc oxide NPs.

Toxicity of Elytraria Acaulis (L. F.) Lindau (Acanthaceae) to the Larvae of Vector Mosquitoes

Synthetic pesticides, which are non-biodegradable and have detrimental effects on the environment, non-targeted organisms, and human health, are often used to control mosquitoes. This situation fostered and prompted the creation of substitutes utilizing natural products like phytoextracts and phytochemicals. The current study was set out to determine the toxicity of leaf extracts from Elytraria acaulis on the early third instar larvae of Aedes aegypti, Anopheles stephensi and Culex quinquefasciatus at doses of 31.5, 62.5, 125, 250, 500 and 1000mg/L at 24 and 48 hours of exposure. All extracts, with the exception of aqueous, demonstrated potent larvicidal effectiveness with 100% larval death in all the three studied vector mosquitoes after 48 hours. The ethanol extract showed the maximum larvicidal activity and 100% larval mortality in Aedes aegypti after 24 hours, and its respective LC50 values against Aedes aegypti, Anopheles stephensi, and Culex quinquefasciatus were 31.98, 560.29, 603.8108mg/L and 20.43, 46.13 and 60.08mg/L after 24 and 48 hours. The treated larvae exhibited extremely restless behaviour, including wiggling, sinking, floating, slowness, paralysis, sinking to the bottom of the glass beaker, and ultimately death. Qualitative phytochemical study of Elytraria acaulis leaves revealed the presence of alkaloids, flavonoids, glycosides, phenolics, saponins, steroids, tannins, terpenes, and terpenoids. The ethanolic extract GC-MS examination identified main phytocompounds, including imidazole, imidazolidinone, phytol, phytol acetate, octacosane, thymol 1-thiocarbonylimidazolide and methoxyacetic acid to determine the larvicidal mechanism of action and the cause of larval death. It is quite exciting to note, based on the results of the current investigation, that Elytraria acaulis leaf extracts, particularly ethanol extract, demonstrated good larvicidal efficacy. The present study documents the first report on the effectiveness of Elytraria acaulis ethanolic leaf extract against the larvae of Aedes aegypti, Anopheles stephensi, and Culex quinquefasciatus.

Bioconversion of chicken feather wastes into value added bioactive peptide by Geobacillus thermodenitrificans PS41 strain

A need for an economically attractive method for feather waste utilization, lead us to research for a new effective technology assuring an outcome of valuable product. In this study, keratinase producing Geobacillus thermodenitrificans a bacterial isolate PS41 was used to convert feather waste into bioactive peptides. Feather peptide under 15 kDa had shown a maximum antioxidant activity and it was identified as radical oxygenase of Propionibacterium acne. The purified feather peptide from PS41 showed antibacterial activity, anticancer activity against human alveolar basal epithelial cells, and larvicidal activity against Aedes aegypti, Anopheles stephensi, and Culex quinquefasciatus larvae in comparison to non-targeted organisms like zebra fish embryo and brine shrimp. The wound healing rate was significantly higher in peptide treated groups in comparison to standard and control groups respectively. Peptide treated wound had exhibited promisingly complete healing after 5 days of treatment in cat fish model and after 12 days of treatment in wistar albino rat. Histological analysis on experimental animal model showed that the tissue regenerating efficacy of peptide was more than the standard.

Essential Oils of Distichochlamys benenica: Chemical Constituents, Mosquito Larvicidal and Antimicrobial Activities

In recent years, essential oils (EOs) have gained popularity for their potential as natural antimicrobial agents and mosquito larvae control. This study aimed to explore the chemical composition of EOs extracted from the leaves and rhizomes of Distichochlamys benenica Q.B. Nguyen & Škorničk, and to evaluate their mosquito larvicidal and antimicrobial activities. The EOs were obtained using hydrodistillation and subjected to gas chromatography (GC) and GC-mass spectrometry to determine their chemical constituents. The main components identified in the leaf EO were β-pinene (47.7%), cis-β-elemene (8.5%), and α-pinene (7.8%), while the rhizome EO mainly consisted of geranyl acetate (25.7%), geranial (23.3%), neral (16.6%), and geraniol (8.4%). The mosquito larvicidal activity of the EOs was evaluated using larvae of Aedes aegypti and Culex quinquefasciatus during 24 and 48 h of treatment. The results demonstrated that these EOs effectively inhibited the mosquito larvae, with LC50 values ranging from 31.15 to 71.53 μg/mL and LC90 values ranging from 46.28 to 148.66 μg/mL. Additionally, the minimum inhibitory concentration (MIC) and half-maximal inhibitory concentration (IC50) values were used to evaluate the antimicrobial efficacy of EOs. Both EOs exhibited potent antimicrobial effects against Enterococcus faecalis ATCC 299212, Staphylococcus aureus ATCC 25923, Bacillus cereus ATCC 14579, Pseudomonas aeruginosa ATCC 27853, and Candida albicans ATCC 10231, with MIC values ranging from 16 to 64 μg/mL and IC50 values ranging from 4.67 to 45.67 μg/mL. Overall, the mosquito larvicidal and antimicrobial activities of D. benenica EOs highlight their potential as natural alternatives for combating mosquito-borne diseases and microbial infections.

RETRACTED: Cellulose microcrystalline: A promising ecofriendly approach to control Culex quinquefasciatus larvae

The growing use of synthetic chemical compounds/substances in vector control of mosquitoes, associated with their adverse effects on the environment and non-target organisms, has demanded the development of eco-friendly alternatives. In this context, this study aimed to evaluate the larvicidal action of different cellulose microcrystalline (CMs) concentrations and investigate their toxicity mechanisms in Culex quinquefasciatus fourth instar larvae as a model species. Probit analysis revealed that the median lethal concentrations (LC50) for 24 h and 36 h exposure were 100 and 58.29 mg/L, respectively. We also showed that such concentrations induced a redox imbalance in the larvae, marked by an increase in the production of reactive oxygen species (ROS) and thiobarbituric acid reactive substances (TBARS), as well as a reduction in the activity of superoxide dismutase (SOD) and catalase (CAT). Furthermore, different alterations in the external morphology of the larvae were associated with the ingestion of CMs. On the other hand, exposure of adult zebrafish (Danio rerio) to LC5024h and LC5036h for seven days did not induce any behavioral changes or alterations mutagenic, genotoxic, biochemical, or in the production of cytokines IFN-γ and IL-10. Thus, taken together, our study demonstrates for the first time that the use of CMs can constitute a promising strategy in the control of C. quinquefasciatus larvae, combining insecticidal efficiency with an “eco-friendly” approach in the fight against an important mosquito vector of several human diseases.