Quinquefasciatus Say Research Articles

Kajian aspek keamanan nyamuk Aedes aegypti Linnaeus ber-Wolbachia di Yogyakarta, Indonesia

Dengue prevention efforts are limited to the control strategies of its vector and the management of breeding sites. New alternatives for dengue vector control that are sustainable and more environmentally friendly are needed to complement the government’s current efforts. Research on Wolbachia-infected Aedes aegypti Linnaeus mosquitoes as an alternative biocontrol strategy has been performed in Yogyakarta City. However, one of the concerns of the community members and stakeholders about this technology is the safety aspect regarding the transmission of Wolbachia to other species and the possibility that humans will contract Wolbachia. This study aimed to address these concerns, namely to find out whether horizontal transmission of Wolbachia occurred from A. aegypti that were released to other species and whether residents living in the released areas were infected with Wolbachia. The research was conducted in Dusun Nogotirto and Dusun Kronggahan (Sleman Regency), as well as in Dusun Jomblangan and Dusun Singosaren (Bantul Regency), Yogyakarta Special Province. Wolbachia qPCR screening using the target gene WD0513 was performed on 922 Culex quinquefasciatus Say and 331 Aedes albopictus (Skuse). ELISA test was carried out on 190 pairs of plasma samples, namely the sample before the Wolbachia frequency was established (still <80%) and the sample after it was established (>80%). The results showed no evidence of Wolbachia transfer from Wolbachia-infected A. aegypti to other mosquito species coexisting in the same habitat or to humans. This study corroborates the safety evidence of Wolbachia-infected A. aegypti technology as an alternative to control dengue virus transmission

Culicidae assemblages of artificial containers and possible biotic interactions affecting Aedes albopictus (Diptera: Culicidae) in Argentina.

In Argentina, the distribution of Aedes albopictus (Skuse) is limited to two provinces with a subtropical climate and few records. This study aims to describe and compare assemblies of Culicidae that breed in artificial containers in two areas with different degrees of urbanisation where Ae. albopictus is present and to evaluate possible biotic interactions. We sampled container larval habitats of an urban (Eldorado city) and a rural environment (Colonia Aurora village). We performed generalized linear mixed models to evaluate which variables (containers characteristics or environment) are associated with the presence and abundance of Ae. albopictus, Aedes aegypti Linneaus and Culex quinquefasciatus Say, and the presence of mosquito predators (Lutzia bigoti (Bellardi) and Toxorhynchites spp.). Also, the relationship between the most abundant species was quantified in each environment using Hurlbert's C8 association coefficient. Ae. aegypti was the most abundant species in the urban environment, while Cx. quinquefasciatus and Ae. albopictus were the most abundant in the rural area. Predators were more present in the rural environment and affected the abundance of Aedes mosquitoes. Regarding the C8 index, Ae. aegypti was negatively associated with Ae. albopictus in the urban area, whereas in the rural area these species presented a significantly positive relationship. These results show that in urban environments the high abundance of Ae. aegypti could be affecting the Asian tiger mosquito as evidenced by local studies of food larval competition. Also a greater presence of predators could be affecting Ae. albopictus in rural environments.

Evaluation of field resistance in field-collected mosquito Culex quinquefasciatus Say through quantification of ULV permethrin/PBO formulation in field bioassays.

Pyrethroids are among the most applied adulticides worldwide to control mosquito vectors for prevention of arboviral diseases transmission. However, pesticide resistance development in a mosquito population could lead to decreased control efficacy. While most studies investigate the resistant genotype (i.e. kdr, CYP450, etc.) as explanatory variables, few field efficacy studies have measured pesticide quantities deposited at different distances from the sprayer in association with observed mosquito mortality. The current study determined field delivered amounts of an applied ULV permethrin/PBO formulation (31% permethrin + 66% piperonyl butoxide) by GC/MS and estimated practical resistance ratios using caged mosquito females. For field samples, the extraction method recovered 78 ± 3.92-108 ± 8.97% of the permethrin/PBO formulation when utilizing the peaks of PBO from GC/MS to estimate the concentrations of adulticide deposited near the mosquito cages. The field bioassay showed that the spatial distribution of permethrin/PBO formulation was heterogeneous among three pseudo-replicates within the same distance. Within the quantifiable permethrin/PBO range of 15.7-51.4 ng/cm2 , field-collected mosquito mortalities started at 64% and linearly increased reaching 100% only in two areas, while all Sebring susceptible mosquitoes died. The field LC95 resistance ratio (RR) of F0 Cx. quinquefasciatus ranged from 2.65-3.51, falling within the 95% CI of RR95 estimated by laboratory vial assays. Tests with and without PBO indicated P450's enzymes contributed to field resistance. Results showed the suitability of the collection and quantification method to estimate the field resistance ratio at the applied pesticide rate. Pesticide quantification would also allow the association of the known frequencies of resistance mechanisms (e.g. kdr, CYP450) with field mortalities to estimate the resistance level conferred by such mechanisms. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Synthesis of Carlina Oxide Analogues and Evaluation of Their Insecticidal Efficacy and Cytotoxicity.

Compounds isolated from botanical sources represent innovative and promising alternatives to conventional insecticides. Carlina oxide is a compound isolated from Carlina acaulis L. (Asteraceae) essential oil (EO) with great potential as bioinsecticide, being effective on various arthropod vectors and agricultural pests, with moderate toxicity on non-target species. Since the production from the wild source is limited, there is the need of exploring new synthetic routes for obtaining this compound and analogues with improved bioactivity and lower toxicity. Herein, the chemical synthesis of carlina oxide analogues was developed. Their insecticidal activity was assessed on the vectors Musca domestica L. and Culex quinquefasciatus Say, and their cytotoxicity was evaluated on a human keratinocyte cell line (HaCaT). The compounds' activity was compared with that of the natural counterparts EO and carlina oxide. In housefly tests, the analogues were comparably effective to purified carlina oxide. In Cx. quinquefasciatus assays, the meta-chloro analogue provided a significantly higher efficacy (LC50 of 0.71 μg mL-1) than the EO and carlina oxide (LC50 1.21 and 1.31 μg mL-1, respectively) and a better safety profile than carlina oxide on keratinocytes. Overall, this study can open the way to an agrochemical production of carlina oxide analogues employable as nature-inspired insecticides.

Efficacy of Mentha aquatica L. Essential Oil (Linalool/Linalool Acetate Chemotype) against Insect Vectors and Agricultural Pests.

In recent years, agrochemical industries have been focused on the development of essential oil (EO)-based biopesticides, which can be considered valuable alternatives to traditional chemical products. The genus Mentha (Lamiaceae) comprises 30 species characterized by a wide range of biological activities, and some of their EOs showed good potential as pesticidal agents. In this regard, the aim of this study was to evaluate the insecticidal activity of the EO obtained from a rare linalool/linalool acetate chemotype of Mentha aquatica L. The EO was found to be highly effective against Culex quinquefasciatus (Say) 2nd instar larvae, Metopolophium dirhodum (Walker) adults, Spodoptera littoralis (Boisduval) 2nd instar larvae, and Tetranychus urticae (Koch) adults, showing lethal concentrations (LC50) or doses (LD50) of 31.5 ± 2.2 µL L-1, 4.9 ± 0.8 mL L-1, 18.5 ± 2.1 µg larvae-1, and 3.3 ± 0.5 mL L-1, respectively. On the contrary, Musca domestica L. adults and 3rd instar larvae of C. quinquefasciatus and S. littoralis were moderately affected by the treatment (LC50 or LD50: 71.4 ± 7.2 µg adult-1, 79.4 ± 5.2 µL L-1, 44.2 ± 5.8 µg larvae-1, respectively). The results obtained in this work demonstrated that various insects and pests could be differently sensible to the same EO and may lead to the exploitation of this plant or its major volatile compounds as novel ingredients of botanical insecticides and pesticides.

Isolation, characterization and larvicidal potential of indigenous soil inhabiting bacteria against larvae of southern house mosquito (Culex quinquefasciatus Say)

Isolation, characterization and larvicidal potential of indigenous soil inhabiting bacteria against larvae of southern house mosquito (Culex quinquefasciatus Say)

Phytochemical screening, GC-MS analysis and larvicidal potentiality of Lantana camara red petals collected from wad Medani City, Gezira State, Sudan

Plants are a major source of medicine with a variety of biological deliberations, including antioxidant, antibacterial, antifungal and insecticidal activities. This study aimed to determine the phytochemical and GC-MS composition, in addition to the larvicidal potentiality of Lantana camara red petals collected from Wad Medani city, Gezira State, Sudan. The dried granules of red petals samples of L. camara were used to run the phytochemical screening tests, whereas the counterpart ethanol extract was used for the GC-MS analysis and the larvicidal potentiality and the morphological deformities using Anopheles arabiensis Patton and Culex quinquefasciatus Say larvae. The results of these tests showed that, flavonoids, steroids and terpenoids were presented in the red petals of L. camara, whereas, alkaloids, glycosides, saponnins and tannins were not detected. The GC-MS identified 42 compounds from the ethanol extract of the red petals, of which Benzyl beta d-glucoside (23.83%), 6-O-acetyl-1[[4-bromophenyl]thio]-beta- (10.12%), Galactopyranoside,1-octylthio-1-deoxy- (9.28%) and the terpenoids caryophyllene (1.40%), Beta-curcumene (1.66%) and Trans-sesquisabinene hydrate (1.72%) were the main components. At the concentration of 1120 mg/L of red ethanol extract, 50% of Anopheles, and 47.5% of Culex larvae were survived after 24 hour, but after 7 days, no one larva of Anopheles nor Culex were survived. The deformation monitored on mosquitoes larvae that submitted to Lantana red flowers were dark and swelled bodies, dark guts, loose bodies, dead and stretched body-pupae, in addition to dead emerged adults and emergence of short wings adults.

Plant pollen as a resource affecting the development and survival of the mosquitoes Anopheles quadrimaculatus and Culex quinquefasciatus (Diptera: Culicidae).

Mosquito larvae often subsist on inputs of terrestrial-derived resources, including leaves and dead insects. However, seasonal inputs of plant pollen is an underexplored resource for many species. We compared the effects of three levels (low, medium, high) of two pollen types (corn, pine) on development, mass, and survival in Anopheles quadrimaculatus (Say) and Culex quinquefasciatus (Say) (Diptera: Culcidae). We also examined the nutrient content of adults (%nitrogen, %carbon, C:N) and stable isotopes (δ15N, δ13C). Culex quinquefasciatus had the highest survival rates when grown on high and medium pine pollen compared with low pine. Survival of Culex quinquefasciatus was generally higher compared to that of An. quadrimaculatus on any level of pine, with the latter species having higher survival in high corn. Nutrient content for An. quadrimaculatus did not vary significantly in either pollen type or amount but were more enriched in δ15N in corn pollen relative to pine pollen. For Cx. quinquefasciatus, %N decreased and C:N ratio increased across low to high amounts of corn. Adults raised in corn had generally more δ13C compared to pine pollen. No developmental differences across diets were observed for either species, however both sexes of Cx. quinquefasciatus were generally larger when grown in high pine and medium and high corn pollen compared with other treatments. The poor performance of An. quadrimaculatus on corn pollen was unexpected, however, we show a benefit of corn pollen to Cx. quinquefasciatus with implications for West Nile virus transmission in the United States, especially around agricultural areas where corn is grown.

Tree canopy cover affects basal resources and nutrient profiles of Aedes and Culex larvae in cemetery vases in New Orleans, Louisiana, United States.

Cemetery vases are important habitat for vector mosquito production, yet there is limited understanding on their food web dynamics and how they vary across environmental gradients. Tree cover is one factor that varies widely across cemeteries, and influence food webs by means of detrital inputs, temperature mediation, and light availability. Such information can be important for determining mosquito adult body size, fecundity, and competition outcomes, all of which may influence mosquito population and disease risk. This study evaluates the relationship between tree canopy cover and indicators of basal resources for Aede aegypti (L.), Aedes albopictuss (Skuse), and Culex quinquefasciatus (Say) larvae, such as stable isotopes (δ13C and δ15N) and nutrient stoichiometry in cemeteries of New Orleans, Louisiana (USA). Stable isotope values suggest that larvae feed directly on the Particulate Organic Matter (POM) suspended in the vase's water, and that POM composition influence the nutrient profiles of mosquito larvae. The POM of open canopy vases had higher δ13C values, than that of closed canopy vases indicating differences in relative proportion of basal carbon sources, with open canopy POM having a lower proportion of allochthonous carbon, and a higher proportion of authoctonous carbon. Accordingly, mosquito larvae collected from open canopy vases had higher δ13C values, and higher C:N than larvae from closed canopy vases. The results of this study show a shift in food web dynamics driven by canopy cover in cemetery vases that directly influence the nutrient profiles of mosquito larvae. The implications for mosquito ecology, and vector management are discussed.

Biocontrol efficacy of apigenin isolated from Anisomeles indica (L.) Kuntze against immature stages of Culex quinquefasciatus (Say, 1823) and its in silico studies

Culex quinquefasciatus is a vector of medical importance since it transmits pathogens to humans, and domestic and wild animals. Synthetic chemical insecticides which are widely used to control mosquitoes are also reported to cause severe threats to humans, non-target organisms and the environment. However, bioactive products derived from plants for mosquito control are eco-friendly, target-specific, safe to non-target organisms, biodegradable, less toxic and reduce development of drug resistance. Therefore, the goal of the present study was to evaluate the biocontrol efficacy of Anisomeles indica (L.) Kuntze on immature stages namely eggs, pupae, and larvae of Cx. quinquefasciatus. In the preliminary screening, hexane and chloroform extracts were found active which were blended and subjected to column chromatography that finally yielded the active phytochemical apigenin. Against Cx. quinquefasciatus, apigenin caused 74% egg mortality at 2 ppm concentration after 120 h of exposure, 72% larvicidal activity with LC50 and LC90 values of 1.3 and 3.9 ppm, respectively, after 24 h, and 65% pupicidal activity with LC50 and LC90 values of 1.3 and 3.7 ppm, respectively, after 24 h exposure. Histopathology study of the exposed larvae revealed that apigenin caused damages on the midgut epithelial columnar cells and remarkable deformities in their structural development, whereas no toxicity was caused on the tested non-target organisms, Gambusia affinis (mosquito fish) and Diplonychus indicus (water bug). Docking study demonstrated that apigenin bounded and inhibited AChE1 of Cx. quinquefasciatus, which resulted in larval mortality. The present study manifested that the isolated metabolite apigenin from A. indica could be a promising biopesticide to control vector mosquitoes.

Desiccation tolerance in larvae of Culex quinquefasciatus Say, 1823 and Anopheles stephensi Liston, 1901 (Diptera: Culicidae): implications for mosquito control

A laboratory assessment of desiccation tolerance in larval stages of mosquitoes Anopheles stephensi Liston, 1901 (Diptera: Culicidae) and Culex quinquefasciatus Say, 1823 (Diptera: Culicidae) was carried out using five temperature levels and three levels of exposure duration as explanatory variables. The increase in the duration of exposure to desiccation from 15 min to 60 min was noted to result in a substantial increase in water loss (in mg) in mosquito larvae. Similarly, the increase in temperature levels was observed to cause larval mortality and a substantial decrease in the emergence of adults. Both the temperature and the duration of exposure to desiccation were found to be influential factors in determining survival and subsequent emergence of adults. Desiccation is a primary factor in determining the survival of mosquito larvae, particularly in the conditions where habitat permanence is uncertain, e.g., in temporary pools and containers serving as mosquito larval habitats. The results of the present study provide a glimpse into the effects of desiccation at varied temperatures and exposure durations on the successful emergence of adults in mosquitoes Cx. quinquefasciatus and An. stephensi. Although primary, the obtained results show that desiccation can be a probable way of regulating the development of mosquito larvae in conditions where the permanence of the habitat for mosquito larvae is uncertain. Further studies on desiccation tolerance may be carried out using different mosquito species that are adapted to temporary pools and containers as sources for breeding.

Diversity, distribution and relative abundance of the mosquito fauna (Diptera: Culicidae) of Malakand and Dir Lower, Pakistan.

The present study was conducted to evaluate the diversity, distribution (C) and relative abundance (RA) of the mosquito fauna (Diptera: Culicidae) of Malakand and Dir Lower, Pakistan. Collection of specimens (n = 1087) was made during September 2018 to July 2019 at six different habitats including freshwater bodies, rice fields, animal sheds, indoors, drains and sewage waters. Specimens were collected through light traps, pyrethrum spray, aspirators and nets and subsequently killed, preserved and then arranged in entomological boxes for identification. Three genera were identified namely Culex, Anopheles and Aedes. A total of fourteen species were identified namely: Cx. quinquefasciatus (Say, 1823), An. stephensi (Liston, 1901), Cx. tritaeniorhynchus (Giles, 1901), Ae. vittatus (Bigot, 1861), An. maculatus (Theobald, 1901), An. fluviatilis (James, 1902), Cx. vishnui (Theobald, 1901), Ae. aegypti (Linnaeus, 1762) An. subpictus (Grassi, 1899), An. dthali (Patton, 1905), An. culicifascies (Giles, 1901), An. pallidus (Theobald, 1901), Ae. albopictus (Skuse, 1894) and An. annularis (van der Wulp, 1884). Cx. quinquefasciatus was found constantly distributed in the study area with RA = 16.5% and C = 100%. An. annularis was found as a satellite species, sporadically distributed in the study area having RA = 0.9% and C = 17%. Diversity indices of mosquitoes in the studied habitats were found as, Shannon-Wiener Index (2.415), Simpson Index (9.919), Fisher's Index (2.269) and Margalef's Index (1.859). A statistically significant difference was recorded in mosquito diversity in the six habitats (Kruskal-Wallis, chi-squared, H = 17.5, df = 5, P = 0.003 at α = 0.05). The present study encompasses mosquito fauna of Malakand, Pakistan with respect to diversity, relative abundance and distribution in diverse habitats and all seasons of the year. This will assist scientists working in various fields related with epidemiology, medical and veterinary entomology, ecology and allied areas of biological sciences.

The Essential Oil from the Resurrection Plant Myrothamnus moschatus Is Effective against Arthropods of Agricultural and Medical Interest.

This work aimed to evaluate the chemical composition, insecticidal and acaricidal potential of the essential oil (EO) obtained from the resurrection plant Myrothamnus moschatus (Baill.) Baill. (Myrothamnaceae) from Madagascar. The EO bioactivity was evaluated against selected arthropod pests and vectors of agricultural and public health relevance. The most abundant volatile compounds were trans-pinocarveol (37.7 ± 4.2%) and pinocarvone (20.8 ± 3.1%), similar to the EO of the chemotype collected from the same region. Lethal concentrations (LC50) or doses (LD50) from acute toxicity tests were estimated for Musca domestica (L.) adults at 22.7 µg adult-1, for Spodoptera littoralis (Boisduval) larvae at 35.6 µg larva-1, for Culex quinquefasciatus (Say) at 43.6 µg mL-1, for adults of Metopolophium dirhodum (Walker) at 2.4 mL L-1, and for adults of Tetranychus urticae (Koch) at 1.2 mL L-1. The good insecticidal and acaricidal activities determined in this work may open a new perspective on the use of this plant as a source of botanical insecticide ingredients. The exploitation of this species could also be important for the African economy, helping local farmers cultivating this plant.

PLANT STEM INFUSED WATER ON MOSQUITOCIDAL ACTIVITY TO CULEX QUINQUEFASCIATUS SAY

Locally available plants, Azadirachta indica, Citrus aurantifolia, Citrus aurantium and Tamarindus indica stems were infused in water and tested efficiency against Culex quinquefasciatus Say (Diptera: Culicidae) life stages. Preliminary phytochemical profiling of the plant infused water reveals the presence of phenolic compounds, tannins, flavonoid, cardiac glycosides and terpenoids. Tannins quantification revealed that C. aurantifolia had significantly more amounts than other plants. Citrus aurantium stem infused water (CASIW) caused more mortality to C. quinquefasciatus larvae and pupae. Furthermore, CASIW increased larval and pupal developmental period and reduced adult longevity. However, tested plants did not affect the morphology of the insect. Results suggested utilize this indigenous technique to minimize C. quinquefasciatus population.

Larvicidal efficacy of selected medicinal plants against the filarial vector mosquito Culex quinquefasciatus Say (Diptera: Culicidae)

The present research was conducted to assess the mosquito larvicidal potential of selected medicinal plants using an effective but simple method. Aqueous extracts of roots of three selected medicinal plants viz. Derris scandens, Rubia cordifolia and Saussurea lappa were evaluated for their mosquito larvicidal potential against the 3rd instar larvae of C. quinquefasciatus Say (1823) under laboratory settings. Aqueous extracts of these plants at seven different concentrations (1, 25, 50, 100, 150, 200 and 300 ppm) exhibited considerable mortality of the 3rd instar larvae after 24 and 48 h exposure. Among the plants, D. scandens root extract exhibited the highest toxicity inducing 100% larval mortality after 24 h exposure at 250 ppm concentration, followed by the root extracts of R. cordifolia and S. lappa inducing 98.4% and 87.8% larval mortality, respectively. Overall, extracts of all the plants exhibited a strong positive correlation between the concentration of extracts and larval mortality (p˂0.001) with a correlation coefficient of more than 0.90. The LC50 and LC90 values after 24 h contact demonstrated D. scandens as the most toxic with the lowest LC50 and LC90 values (LC50=78.20 ppm, LC90=147.33 ppm) followed by R. cordifolia (LC50= 89.32 ppm, LC90=204.09 ppm) and S. lappa (LC50=112.29 ppm, LC90=248.72 ppm), respectively. Our results clearly indicated that all the plants' aqueous extracts showed considerable larvicidal potential against the 3rd instar larvae of C. quinquefasciatus. To conclude, the application of aqueous extracts from these plants to larval habitats may efficiently control C. quinquefasciatus mosquitoes, hence, can be recommended as a potential alternative to chemical insecticides against these vectors. Asian J. Med. Biol. Res. 2022, 8 (4), 187-193

Predatory efficiency of dragonfly nymphs, Crocothemis servilia and Rhyothemis variegata against the mosquito, Culex quinquefasciatus Say

This study compared the predatory potential of nymphs of two dragonfly species viz. Crocothemis servilia (Drury, 1773) and Rhyothemis variegata (Linnaeus, 1763) using the different larval instars and pupae of Cx. quinquefasciatus (Say, 1823) as preys in normal laboratory settings. Field-collected fed and 24 h starved nymphs of C. servilia and R. variegata were offered 1st, 2nd, 3rd and 4th instar larvae and pupae of Cx. quinquefasciatus to monitor the rate of predation. A 24 h starved nymph of C. servilia showed the highest predation on the 2nd instar larvae (92.00±4.06%) followed by the 3rd (83.00±5.61%), 4th (80±6.89%) and 1st (76.00±4.85%) instar larvae and the pupae (26.00±2.91), respectively, whereas, that of R. variegata exhibited the highest consumption of the 1st instar larvae (90.00±3.54 %) followed by the 2nd (88.00±5.61 %), 3rd (82.00±3.74 %), 4th (70.00±7.91 %) larval instar and the pupae (23.00±4.63), respectively within 24 h exposure. In the same period, the fed nymphs of C. servilia showed maximum consumption of the 2nd instar larvae (77.00±3.54%) followed by the 3rd (76.00±4.58%), 4th (64.00±4.00%) and 1st instar (55.00±3.53%) larvae and the pupae (24.00±3.67), respectively, whereas, that of R. variegata exhibited highest consumption of the 1st instar larvae (67.00±5.38 %) followed by the 2nd (65.00±10.12 %), 3rd (58.00±8.46 %) and 4th (53.00±4.06 %) instar larvae and the pupae (21.00±2.92), respectively. The rate of predation was significant on all the larval instars and the pupae compared to their control counterparts (p<0.05) and the starved larvae and nymphs of both the dragonfly species showed higher predation compared to the fed nymphs. The aforementioned findings suggest that nymphs of both of the dragonfly species exhibited considerable predation potential against the immature stages of the Cx. quinquefasciatus mosquito. The present study recommends assessing the feasibility of using these species in large-scale mosquito control programs.

A highly expressed odorant receptor from the yellow fever mosquito, AaegOR11, responds to (+)- and (−)-fenchone and a phenolic repellent

The cornerstone of the reverse chemical ecology approach is the identification of odorant receptors (OR) sensitive to compounds in a large panel of odorants. In this approach, we de-orphanize ORs and, subsequently, measure behaviors elicited by these semiochemicals. After that, we evaluate behaviorally active compounds for applications in insect vector management. Intriguingly, multiple ORs encoded by genes highly expressed in mosquito antennae do not respond to any test odorant. One such case is CquiOR125 from the southern house mosquito, Culex quinquefasciatus Say. To better understand CquiOR125's role in Culex mosquito olfaction, we have cloned a CquiOR125 orthologue in the genome of the yellow fever mosquito, Aedes aegypti (L.), AaegOR11. Unlike the unresponsive nature of the orthologue in Cx. quinquefasciatus, oocytes co-expressing AaegOR11 and AaegOrco elicited robust responses when challenged with fenchone, 2,3-dimethylphenol, 3,4-dimethylphenol, 4-methycyclohexanol, and acetophenone. Interestingly, AaegOR11 responded strongly and equally to (+)- and (−)-fenchone, with no chiral discrimination. Contrary to reports in the literature, fenchone did not show any repellency activity against Ae. aegypti or Cx. quinquefasciatus. Laboratory and field tests did not show significant increases in egg captures in cups filled with fenchone solutions compared to control cups. The second most potent ligand, 2,3-dimethylphenol, showed repellency activity stronger than that elicited by DEET at the same dose. We, therefore, concluded that AaegOR11 is a mosquito repellent sensor. It is feasible that CquiOR125 responds to repellents that remain elusive.

Diversity and functional profile of gut symbiotic bacteria between Lysinibacillus sphaericus C3-41 susceptible and resistant Culex quinquefasciatus Say as revealed by 16S rRNA gene high-throughput sequencing.

Previous studies have demonstrated that symbiotic gut bacteria in insects are involved in the development of insecticide resistance, but the relationship between the symbiotic gut bacteria and resistance to Lysinibacillus sphaericus C3-41 in Culex pipiens quinquefasciatus remains unclear. In this study, the abundance and diversity of gut symbionts of Cx. quinquefasciatus that were resistant (RLCql) or susceptible (SLCql) to L. sphaericus C3-41 were analyzed by high-throughput 16S rRNA sequencing. The main phyla among the symbiotic gut bacterial communities of Cx. quinquefasciatus were Proteobacteria, Actinobacteria, Firmicutes, and Bacteroidetes. However, the relative abundance of Firmicutes, Proteobacteria, and unidentified Bacteria in the gut of the resistant strain of Cx. quequinfasciatus (RLCql colony) was higher compared to the susceptible strain (SLCql colony). The NMDS (Non-Metric Multi-Dimensional Scaling) and unweighted unifrac PCoA analyses also revealed significant differences between the symbiotic gut bacterial communities from the resistant and susceptible strains, suggesting that bacterial insecticides can alter bacterial composition. Ultimately, the changes in the bacterial community likely occurred after the development of resistance to L. sphaericus C3-41. These results provide guidance for further research into the mechanisms of gut symbionts involved in resistance against L. sphaericus C3-41 in Cx. quinquefasciatus.

Sustainable development through the bio-fabrication of ecofriendly ZnO nanoparticles and its approaches to toxicology and environmental protection.

Mosquito control is becoming more difficult as a result of the rise in resistance to toxic chemical insecticides. The insecticides of bio-fabrication sources may serve as a convenient alternative to environmentally acceptable methods in the future. The larvicidal and pupicidal activities of bio-fabricated zinc oxide nanoparticles (ZnO NPs) on the different instar larvae and pupae of Anopheles subpictus Grassi (Malaria vector) and Culex quinquefasciatus Say (lymphatic filariasis) were investigated in this study. The results recorded from XRD, FTIR, SEM-EDX, and TEM analyses confirmed the bio-fabrication of ZnO NPs. Such nanoparticles were nearly spherical and agglomerated with a size of 34.21 nm. GC-MS analysis of methanol extract revealed the compound, stigmasterol (C29H48O) as major one. Mosquito larvae and pupae of targeted mosquito were tested against varied concentrations of the bio-fabricated ZnO NPs and methanol extract of Vitex negundo for 24 h. The maximum activity was recorded from ZnO NPs against the larvae and pupae of A. subpictus LC50 which were 1.70 (I), 1.66 (II), 1.93 (III), 2.48 (IV), and 3.63 mg/L (pupa) and C. quinquefasciatus LC50 were 1.95 (I), 2.63 (II), 2.90 (III), 4.32 (IV), and 4.61 mg/L (pupa) respectively. ZnO NPs exhibited strong DPPH radical and FRAP scavengers compared to the aqueous extract of V. negundo. Also, V. negundo leaf methanol extract (VNLME) and ZnO NPs were evaluated for their cytotoxicity on HeLa cells, which exhibited the IC50 values of 72.35 and 43.70μg/mL, respectively. The methylene blue (MB) dye, which is harmful to both aquatic and terrestrial life, was degraded using the biosynthesized ZnO nanoparticles. At 664 nm, 81.2% of the MB dye had degraded after 120 min of exposure to sunlight. Overall, our results revealed that ZnO NPs are the perfect biological agent and economical for the control of malaria, filariasis vectors, antioxidant, HeLa cells, and MB blue dye degradation under sunlight irradiation.Graphical abstract

The Antibacterial and Larvicidal Potential of Bis-(2-Ethylhexyl) Phthalate from Lactiplantibacillus plantarum.

Lactic acid bacteria produce a variety of antibacterial and larvicidal metabolites, which could be used to cure diseases caused by pathogenic bacteria and to efficiently overcome issues regarding insecticide resistance. In the current study, the antibacterial and larvicidal potential of Bis-(2-ethylhexyl) phthalate isolated from Lactiplantibacillus plantarum BCH-1 has been evaluated. Bioactive compounds were extracted by ethyl acetate and were fractionated by gradient column chromatography from crude extract. Based on FT-IR analysis followed by GC-MS and ESI-MS/MS, the active compound was identified to be Bis-(2-ethylhexyl) phthalate. Antibacterial potential was evaluated by disk diffusion against E. coli (12.33 ± 0.56 mm inhibition zone) and S. aureus (5.66 ± 1.00 mm inhibition zone). Larvicidal potency was performed against Culex quinquefasciatus Say larvae, where Bis-(2-ethylhexyl) phthalate showed 100% mortality at 250 ppm after 72 h with LC50 of 67.03 ppm. Furthermore, after 72 h the acetylcholinesterase inhibition was observed as 29.00, 40.33, 53.00, 64.00, and 75.33 (%) at 50, 100, 150, 200, and 250 ppm, respectively. In comet assay, mean comet tail length (14.18 ± 0.28 μm), tail DNA percent damage (18.23 ± 0.06%), tail movement (14.68 ± 0.56 µm), comet length (20.62 ± 0.64 µm), head length (23.75 ± 0.27 µm), and head DNA percentage (39.19 ± 0.92%) were observed at 250 ppm as compared to the control. The current study for the first time describes the promising antibacterial and larvicidal potential of Bis-(2-ethylhexyl) phthalate from Lactiplantibacillus plantarum that would have potential pharmaceutical applications.