Effects of a Neonicotinoid on Indigenous Earthworm Perionyx excavatus Biochemical and Histopathological Alterations.

Acetamiprid is a broad-spectrum insecticide, belonging to the neonicotinoid compounds group, which has been extensively applied throughout the globe. Recently, indiscriminate use of these compounds was reported to cause fatal impacts on non-targeted soil organisms. Hence, the present study aimed to examine the impact of acetamiprid on Indian indigenous earthworm, Perionyx excavatus. Acute toxicity revealed an LC50 concentration of 0.25 µg/cm2 for filter paper test/72 h and 400 µg/kg for artificial soil test/14 days. Oxidative stress (ROS) and various biomarkers including superoxide dismutase, catalase, glutathione S-transferase, malondialdehyde content and DNA damage were measured. The results of the biomarker responses confirmed the acetamiprid exposure can cause toxicity to P. excavatus. In addition, cell density (20 × 102 cell mL/mg) and cell viability (40%) were significantly (p < 0.05) reduced. Further, the ecotoxicological assessment made through this study can be utilized as good evidence to toxicity of neonicotinoids to non-targeted indigenous organisms.

Biodegradation of neonicotinoid insecticide acetamiprid by earthworm gut bacteria Brucella intermedium PDB13 and its ecotoxicity.

Extensive use of neonicotinoid insecticides in recent decade had contaminated water and soil systems and poses serious environmental and health risk. Microbial degradation of toxic contaminants in the environment has been established as a sustainable tool towards its remediation. Under this context, the present study focused on the biodegradation of neonicotinoid insecticide acetamiprid, by bacterial strain Brucella intermedia PDB13 isolated from the gut of the acetamiprid exposed earthworms. To enhance acetamiprid biodegradation, suitable parameters such as pH, temperature, inoculum size and acetamiprid concentration range were optimised using Response Surface Methodology (RSM). The experimental results showed that the Brucella intermedium PDB13 can tolerate and degrade relatively high concentrations of acetamiprid (50 - 350 mg L-1). The results confirmed that maximum degradation of about 89.72% was achieved under optimized conditions. Further, confirmation of acetamiprid biodegradation was assessed through the occurrence of its degraded metabolites through HPLC, FTIR, and LCMS analysis. Based on this analysis, possible acetamiprid biodegradation pathway by Brucella intermedia PDB13 was proposed. Additionally, cytotoxicity, earthworm acute toxicity, and zebrafish embryo toxicity studies were also performed to assess the toxicity variations between the parent compound and its metabolites. The acetamiprid treated group resulted in cytotoxic effects apparently, with the increase in aberrant cells frequency (22.5 ± 3.3), when compared with its metabolites (2.3 ± 4.3) and control (1.9 ± 5.6) respectively. All these results evidently reported the degradation potential of Brucella intermedia PDB13, thereby establishing the scope for further advanced biodegradation studies towards mitigating the pesticide pollution.

Synthesizing Ag2Ox(3 wt%)-loaded ZnFe2O4 photocatalysts for efficiently saving polluted aquatic ecosystems.

Herein, we report an Ag2Ox (3 wt%)-loaded ZnFe2O4 photocatalysts synthesized by co-precipitation and incipient wet impregnation approach for acetamiprid degradation, antibacterial, antioxidant, and toxicity assay. Initially, bare ZnFe2O4 nanostructures were made through a simple co-precipitation method. In the second step, 3 wt% of various transition metal oxides (CuOx, ZrOx, and Ag2Ox) were embedded on the surface of ZnFe2O4 photocatalysts via a wet impregnation method. Further, the prepared photocatalysts were systematically characterized using XRD, FTIR, FE-SEM, BET, HRTEM, and XPS analysis. The optimum Ag2Ox (3 wt%)-loaded ZnFe2O4 photocatalysts revealed higher degradation efficiencies for acetamiprid under sunlight irradiation. Additionally, the Ag2Ox (3 wt%)-loaded ZnFe2O4 photocatalysts showed more effective antioxidant and antibacterial activity than blank and bare ZnFe2O4 nanomaterials. The enriched catalytic efficiency can be accredited to the 3 wt% of Ag2Ox NPs loaded on ZnFe2O4 nanomaterials, possibly due to the boosted transport properties of the electron-hole pairs. This study will provide a new avenue for the development of simple and effective photocatalysts for efficiently saving polluted aquatic ecosystems.

Efficient One-Pot Synthesis of TiO2/ZrO2/SiO2 Ternary Nanocomposites Using Prunus × Yedoensis Leaf Extract for Enhanced Photocatalytic Dye Degradation.

A simple, efficient, and ecofriendly method was employed to synthesize TiO2/ZrO2/SiO2 ternary nanocomposites using Prunus × yedoensis leaf extract (PYLE) that shows improved photocatalytic and antibacterial properties. The characterization of the obtained nanocomposites was done by X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, field-emission scanning electron microscopy (FE-SEM), and energy-dispersive X-ray spectroscopic (EDS) analysis. The synthesized ternary nanocomposites with nanoscale pore diameters were investigated for the elimination of Reactive Red 120 (RR120) dye. The obtained results showed about 96.2% removal of RR120 dye from aqueous solution under sunlight irradiation. Furthermore, it shows promising antibacterial activity against Staphylococcus aureus and Escherichia coli. The improved photocatalytic and antibacterial activity of TiO2/ZrO2/SiO2 may bring unique insights into the production of ternary nanocomposites and their applications in the environment and biomedical field.

Fabrication, optimization, and characterization of noble silver nanoparticles from sugarcane leaf (Saccharum officinarum) extract for antifungal application.

Metal nanoparticles obtained from green route are gaining significant prominence as a result of their potential applications in nanomedicine and material engineering. Overall metal nanoparticles studied, silver nanoparticles (AgNPs) clutch prominent place in nanoparticles research field. Herein, we have reported the green synthesis of Saccharum officinarum leaf biomass extract-mediated synthesis of AgNPs. Initial nanoparticle production was confirmed by visual observation as color change from light yellow to bright brown color with yellow shade and spectrophotometrically at 450 nm and the various reaction conditions were optimized. The FTIR spectra of the biomass extract and synthesized AgNPs authorized the presence of phyto constituents as capping agent. The High Resolution-Transmission Electron Microscopy (HR-TEM) analyses confirm the morphology and the average particle size of AgNPs as ~28.2 nm. The crystalline nature oxide state and mean particle diameter of AgNPs were confirmed by X-ray diffraction (XRD) analysis, Selected Area Electron Diffraction (SAED) pattern and face-centered cubic (FCC). The obtained AgNPs show moderate to good antifungal activity against Phytophthora capsici, Colletotrichum acutatum and Cladosporium fulvum as 10, 12 and 14 mm zones of inhibition against synthesized AgNPs at 250 µg/well, respectively.

Green synthesis of silver oxide nanoparticles and its antibacterial activity against dental pathogens.

In the present study, the use of silver oxide nanoparticles (Ag2O NPs) synthesized using Ficus benghalensis prop root extract (FBPRE) as a reducing and stabilizing agent is reported and evaluated for its antibacterial activity against dental bacterial strains. The effects of pH, extract concentration, metal ion concentration, and contact time were studied to confirm the optimum production of Ag2O NPs. Our results suggest that, by increasing the extract concentration and the time frame, there will be a significant increase in the formation of nanoparticles. The UV-vis adsorption spectra show the absorbance peak in the range of 430 nm, and FTIR spectral peaks indicate that the phytochemicals in the extract are responsible for the formation of the nanoparticles. The HR-TEM image, SAED, and XRD pattern confirmed the morphology (spherical), silver oxide 42.7 nm and silver 51.4 nm, and crystalline nature of the obtained nanoparticles, respectively. The blend of FBPRE and Ag2O NPs showed excellent antibacterial activities against the two-dental bacteria Streptococcus mutans and Lactobacilli sp. The study results suggest that the blend of synthesized Ag2O NPS and FBPRE will be useful in tooth paste as a germicidal agent after extensive investigation with animal models.

Organochlorine pesticides in commercial marine fishes of Coimbatore, India and their suitability for human consumption.

Organochlorine pesticide residues were determined in 10 species of fishes caught at Cochin and Rameshwaram coast, and sold in Coimbatore, Tamil Nadu, India. Species were selected on the basis of their regular availability throughout the year and commercial value. A total of 389 fishes were analyzed for organochlorine residues and their suitability for human consumption was evaluated. Results show varying levels of residues of hexachlorocyclohexane (HCH), DDT, heptachlor epoxide, endosulfan and dieldrin. Among the 10 species, high concentration of pesticide residues were recorded in Sardinella longiceps, Carangoides malabaricus, Chlorophthalmus agassizi, Saurida tumbil and Rastrelliger kanagurta. The variation in total organochlorine residues among species and between places was not significant (P>0.05). Only five species of fishes showed monthly variation in residue levels and there was no significant correlation between the body size and residue levels in the tissue. About 22% of the fishes exceeded the maximum residue limits (MRL) of total HCH prescribed by FAO/WHO for fish products. The calculated dietary intake of total HCH through consumption of C. malabaricus, C. agassizi and S. longiceps exceeded the maximum acceptable dietary intake (ADI) limits prescribed for human consumption. The present study recommends continuous monitoring of environmental contaminants in marine fishes to assess the possible impact on human health.