Biosurfactants produced by Bacillus subtilis A1 and Pseudomonas stutzeri NA3 reduce longevity and fecundity of Anopheles stephensi and show high toxicity against young instars

Anopheles stephensi acts as vector of Plasmodium parasites, which are responsible for malaria in tropical and subtropical areas worldwide. Currently, malaria management is a big challenge due to the presence of insecticide-resistant strains as well as to the development of Plasmodium species highly resistant to major antimalarial drugs. Therefore, the present study focused on biosurfactant produced by two bacteria Bacillus subtilis A1 and Pseudomonas stutzeri NA3, evaluating them for insecticidal applications against malaria mosquitoes. The produced biosurfactants were characterized using FT-IR spectroscopy and gas chromatography-mass spectrometry (GC-MS), which confirmed that biosurfactants had a lipopeptidic nature. Both biosurfactants were tested against larvae and pupae of A. stephensi. LC50 values were 3.58 (larva I), 4.92 (II), 5.73 (III), 7.10 (IV), and 7.99 (pupae) and 2.61 (I), 3.68 (II), 4.48 (III), 5.55 (IV), and 6.99 (pupa) for biosurfactants produced by B. subtilis A1 and P. stutzeri NA3, respectively. Treatments with bacterial surfactants led to various physiological changes including longer pupal duration, shorter adult oviposition period, and reduced longevity and fecundity. To the best of our knowledge, there are really limited reports on the mosquitocidal and physiological effects due to biosurfactant produced by bacterial strains. Overall, the toxic activity of these biosurfactant on all young instars of A. stephensi, as well as their major impact on adult longevity and fecundity, allows their further consideration for the development of insecticides in the fight against malaria mosquitoes

Synthesis, characterization and dose dependent antimicrobial and anti-cancerous activity of phycogenic silver nanoparticles against human hepatic carcinoma (HepG2) cell line

In the present study silver nanoparticles (AgNPs) were successfully synthesized using aqueous extract of sea weed, Gracilaria corticata. The aqueous callus extract (5%) treated with 1 mM silver nitrate solution resulted in the formation of AgNPs and the surface plasmon resonance (SPR) of the formed AgNPs was recorded at 405 nm using UV-Visible spectrophotometer. The molecules involved in the formation of AgNPs were identified by Fourier transform infrared spectroscopy (FT-IR), surface morphology was studied by using scanning electron microscopy (SEM), and X-ray diffraction spectroscopy (XRD) was used to determine the crystalline structure. SEM micrograph clearly revealed the size of the AgNPs was in the range of 20–55 nm with spherical, hexagonal in shape and poly-dispersed nature. High positive Zeta potential (22.9 mV) of formed AgNPs indicates the stability and XRD pattern revealed the crystal structure of the AgNPs by showing the Bragg’s peaks corresponding to (111), (200), (220) planes of face-centered cubic crystal phase of silver. The synthesized AgNPs exhibited effective anticancerous activity (at doses 6.25 and 12.5 µg/ml of AgNPs) against human hepatic carcinoma cell line (HepG2)

Specific charge separation of Cd doped TiO2 photocatalysts for energy applications

Titanium dioxide (TiO2) nanostructures are well known for their excellency in photocatalytic activities. In this work, additive-free and Cd metal ion - incorporated titanium dioxide (TiO2) nanoparticles have been prepared to employ a facile route of synthesis using a hydrothermal method. Metal-metal nanocomposites have been synthesized by incorporating cadmium (Cd) with the appropriate amount of TiO2 nanoparticles. The properties of the derived materials had been investigated by employing various characteristic tools such as various techniques, including X-ray diffraction (XRD), Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), UV–visible absorbance spectroscopy (UV–vis), and photoluminescence spectroscopy (PL) are all examples of advanced imaging techniques, that may be used to study materials. Using a method known as a vibrating sample magnetometer, we measured the magnetic properties of bare and Cd-doped TiO2 nanoparticles. The investigations on crystalline nature of samples are agreed well with the standard crystalline features of TiO2 nanoparticles. Emerged grain sizes have been estimated for all samples of pure and additive incorporated TiO2 samples. Morphological characterization revealed that different particle features varied with the compositional changes. Spectral and optical absorption spectra of the prepared nanoparticles ensured the yield of derived TiO2 nanoparticles with the additive component. An evaluation of the photocatalytic activity of Cd doped TiO2 nanoparticles under UV irradiation was made using the methylene blue (MB) degradation method. The photodegradation efficiency were studied under visible light which confirms that the material is gifted one for water-treatment technologies to meet the rising clean water shortage