In the current study, prickly pear peel waste (PPPW) extract was used for the biosynthesis of selenium nanoparticles through a green and eco-friendly method for the first time. The biosynthesized SeNPs were characterized using UV-Vis, XRD, FTIR, TEM, SEM, EDX, and mapping. Characterization results revealed that biosynthesized SeNPs were spherical, polydisperse, highly crystalline, and had sizes in the range of 10–87.4 nm. Antibacterial, antifungal, and insecticidal activities of biosynthesized SeNPs were evaluated. Results revealed that SeNPs exhibited promising antibacterial against Gram negative (E.coli and P. aeruginosa) and Gram positive (B. subtilis and S. aureus) bacteria where MICs were 125, 125, 62.5, and 15.62 µg/mL, respectively. Moreover, SeNPs showed potential antifungal activity toward Candida albicans and Cryptococcus neoformans where MICs were 3.9 and 7.81 µg/mL, respectively. Furthermore, tested crud extract and SeNPs severely induced larvicidal activity for tested mosquitoes with LC50 and LC90 of 219.841, 950.087 mg/L and 75.411, 208.289 mg/L, respectively. The fecundity and hatchability of C. pipiens mosquito were significantly decreased as applied concentrations increased either for the crude or the fabricated SeNPs extracts. In conclusion, the biosynthesized SeNPs using prickly pear peel waste have antibacterial, antifungal, and insecticidal activities, which can be used in biomedical and environmental applications.

View related articles View Crossmark data Citing articles: 7 View citing articles Latent effect of gamma irradiation on reproductive potential and ultrastructure of males' testes of Culex pipiens (Diptera; Culicidae

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In the present study, gamma radiation effects on the reproductive potential of the mosquito, Culex pipiens and its role in the transmission of the Hepatitis C Virus (HCV) were investigated. The susceptibility of female, Culex pipiens mosquitoes to gamma irradiation was carried out by exposed full grown pupae to doses 0, 20, 40, 60 Gy. The lethal doses were calculated, as the doses of gamma radiation increased, a progressive increase in the nonhatched eggs percentage. The viral load at mouth parts, in mid-gut and salivary gland, was detected in the irradiated females with LD 75 (60 Gy) and non-irradiated using RT-PCR relatively at time 60 min., 5 and 13 days and tested in the mentioned position. Viral load in irradiated Culex pipiens that fed on an infected blood with a viral load 1.2 x 10 6 IU/ml %was decreased by time from 6.0782 x 10 4 IU/ML% at zero time into 2.399 x 10 3 IU/ML% after 60 min. postinfection at the mouth parts. Also, the viral load decreased by time in the mid-gut from 2.63575 x 10 5 IU/ML% at zero time into 3.969 x 10 3 IU/ML% after 5 days post-infection, while HCV was not detected in the salivary glands. The current results indicated that the mechanical transmission through mouth parts in irradiated and nonirradiated Culex pipiens mosquitoes is plausible while the biological transmission did not occur.

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In this study, the crude extract and its isolated compounds from the stem bark of Annickiachlorantha were tested for their larvicidal, developmental, and repellent activity against the mosquito vector, Culex pipiens, besides their toxicity to the non-target aquatic organism, the zebrafish (Danio rerio). The acute larvicidal activity of isolated compounds; namely, palmatine, jatrorrhizine, columbamine, β-sitosterol, and Annickiachlorantha methanolic extract (AC), was observed. Developmentally, the larval duration was significantly prolonged when palmatine and β-sitosterol were applied, whereas the pupal duration was significantly prolonged for almost all treatments except palmatine and jatrorrhizine, where it shortened from those in the control. Acetylcholinesterase (AChE) enzyme showed different activity patterns, where it significantly increased in columbamine and β-sitosterol, and decreased in (AC), palmatine, and jatrorrhizine treatments, whereas glutathione S-transferase (GST) enzyme was significantly increased when AC methanolic extract/isolated compounds were applied, compared to the control. The adult emergence percentages were significantly decreased in all treatments, whereas tested compounds revealed non-significant (p > 0.05) changes in the sex ratio percentages, with a slight female-to-male preference presented in the AC-treated group. Additionally, the tested materials revealed repellence action; interestingly, palmatine and jatrorrhizine recorded higher levels of protection, followed by AC, columbamine, and β-sitosterol for 7 consecutive hours compared to the negative and positive control groups. The non-target assay confirms that the tested materials have very low toxic activity compared to the reported toxicity against mosquito larvae. A docking simulation was employed to better understand the interaction of the isolated compounds with the enzymes, AChE and GST. Additionally, DFT calculations revealed that the reported larvicidal activity may be due to the differing electron distributions among tested compounds. Overall, this study highlights the potential of A. chlorantha extract and its isolated compounds as effective mosquitocidal agents with a very low toxic effect on non-target organisms.