Visible-light reduced silver nanoparticles' toxicity in Allium cepa test system.

Silver nanoparticles (AgNPs) are widely used in consumer products due to their antibacterial property; however, their potential toxicity and release into the environment raises concern. Based on the limited understanding of AgNPs aggregation behavior, this study aimed to investigate the toxicity of uncoated (uc-AgNP) and coated with polyvinylpyrrolidone (PVP-AgNP), at low concentrations (0.5-100 ng/mL), under dark and visible-light exposure, using a plant test system.

Cloning, partial sequencing and expression analysis of the neural form of P450 aromatase (cyp19a1b) in the South America catfish Rhamdia quelen.

Brain aromatase is a key enzyme exclusively expressed in fish radial glial cells that convert androgens into estrogens, thus controlling neuroendocrine functions and neurogenesis. As an important step in characterizing the neuroendocrine systems of Rhamdia quelen (jundiá), a partial cDNA sequence (1045 bp) of brain aromatase (cyp19a1b) was cloned and sequenced. At the nucleotide level the cDNA sequence was found to be 88% identical to cyp19a1b of two species of catfish, Ictalurus punctatus and Silurus meridionalis.