ABSTRACT
We assessed lethal and sublethal side-effects of Ludox TMA silica nanoparticles on a terrestrial pollinator, Bombus terrestris (Linnaeus), via a dietary exposure. Dynamic light scattering analysis confirmed that silica Ludox TMA nanoparticles remained in suspension in the drinking sugar water. Exposure of bumblebee microcolonies during 7 weeks to the different nanoparticle concentrations (high: 34, 170 and 340 mg/l and low: 34 and 340 µg/l) did not cause worker mortality compared to the controls. Also no effect on the worker foraging behavior was observed after exposure to nanoparticles concentrations up to 340 µg/l. In contrast, the high concentrations (≥34 mg/l) resulted in a total loss of reproduction. Using histological analysis we confirmed severe midgut epithelial injury in intoxicated workers (≥34 mg/l). Despite the fact that these concentrations are much higher than the predicted environmental concentrations, precaution is still needed as information regarding their fate in the terrestrial environment and their potency to bioaccumulate and biomagnificate is lacking.
Subject(s)
Intestinal Mucosa/drug effects , Nanoparticles/toxicity , Silicon Dioxide/toxicity , Analysis of Variance , Animals , Bees , Behavior, Animal/drug effects , Histocytochemistry , Intestinal Mucosa/chemistry , Nanoparticles/chemistry , Particle Size , Reproduction/drug effects , Silicon Dioxide/chemistryABSTRACT
Neurodegenerative diseases (e.g., Alzheimer's Disease, Parkinson's Disease and Amyotrophic Lateral Sclerosis), are characterized by the deposition of misfolded proteins (alpha beta-peptide, alpha-synucleine and Cu, Zn superoxide dismutase, respectively). Oxidative stress is accompanied by the diminished level of catecholamines in neuronal tissue. Beside their role in transduction of nervous stimuli, catecholamines might act as antioxidants. Herein, we focused on the antioxidant activity of catecholamine neurotransmitters--dopamine (and its precursor L-DOPA), adrenaline and noradrenaline. There is an increasing evidence that catecholamines might act as scavengers of free radicals and experimental data indicate the antioxidant potency of catecholamines. However, the exact mechanism of this action is not defined.
