“…In embryos, AChE level increases during gastrulation and post-gastrulation, as it is probably involved in the neuronal differentiation (Akasaka et al, 1986;Ohta et al, 2009). AChE is known to be an essential enzyme for cholinergic neurotransmission in both vertebrates and invertebrates, including sea urchin, and its measurement is used as biomarkers of neurotoxicity in several environmental studies (Cappello et al, 2015;D'Agata et al, 2014b;De Domenico et al, 2013;Fasulo et al, 2010a;Matozzo et al, 2005). The enzymatic analysis of AChE activity performed in this study on pluteus stages showed a slight inhibition at NP exposures lower than 7 ppb in respect to negative control, and a drastic decrease at the higher concentrations and in the positive control.…”