Impacts of dietary exposure to sodium or potassium salts of nitrate and nitrite on the development of Drosophila melanogaster

Potential health risk and bio-accessibility of metal and minerals in saltpetre (a food additive)

Food additives are used to enhance freshness, safety, appearance, flavour, and texture of food. Depending on the absorbed dose, exposure method, and length of exposure, heavy metals in diet may have a negative impact on human health. The X-Ray Fluorescence (XRF) Analyzer from Niton Thermo Scientific (Mobile Test S, NDTr-XL3t-86956, com 24) was used in this work to measure the heavy metal content in saltpetre, a food additive that mostly contains potassium nitrate. The average essential metal concentrations in the samples were determined to be 27044.27 ± 10905.18 mg kg^-1, 24521.10 ± 6564.28 mg kg^-1, 2418.33 ± 461.50 mg kg^-1, and 4.615 ± 3.59 mg kg^-1 for Ca, K, Fe and Zn respectively. Toxic metals (As, Pb) were present in the saltpetre samples at 4.13 ± 2.47 mg kg^-1 and 2.11 ± 1.87 mg kg^-1 average concentrations. No traces of mercury or cadmium were detected. Studies on exposure, health risks, and bio-accessibility identified arsenic as a significant risk factor for potential illnesses. The need to monitor heavy metal content of saltpetre and any potential health effects on consumers is brought to light by this study.

Silver nanoparticle-induced developmental inhibition of Drosophila melanogaster accompanies disruption of genetic material of larval neural stem cells and non-neuronal cells

A few studies had determined the effects of silver nanoparticles on the development of Drosophila melanogaster. However, none had addressed its genotoxic effects on specific larval cells of the fly in details. This study was conducted to determine the effects of silver nanoparticle on the development of D. melanogaster with simultaneous evaluation of its genotoxic potential on specific larval cell types that play important roles in immunological defenses as well as growth and development. Five male and five female flies were maintained in standard Drosophila melanogaster culture medium containing varying concentrations of silver nanoparticles, i.e., 25, 50, 100, 200, and 300 mg/l with control culture medium containing no nanoparticle. Total time needed for stage-specific development, population yield, and genotoxic effects on third instar larval polytene chromosomes, hemocytes, and neuroblasts was determined. Body pigmentation of pupae and young adults was examined visually. In comparison with control, silver nanoparticles dose dependently inhibited the metamororphosis and population yields of pupae and young adults of Drosophila melanogaster. Every concentration of the nanoparticles inhibited pupa to adult conversion, with huge reduction under the influence of nanoparticle concentration of 100 mg/ml and above. Developmental inhibition was accompanied by dose-dependent and significant structural aberrations of larval polytene chromosomes and deformities of hemocytes and neuroblasts. Pupae and young adults also exhibited gradual discoloration of body with the increase in exposure to nanoparticle concentration.