Effects of copper oxide nanoparticles on reproductive system of zebrafish

Copper oxide nanoparticles (CuO NPs) were regarded as the versatile materials in daily life and the in-depth evaluation of their biological effects is of great concern. Herein the female and male zebrafishes were chosen as the model animals to analyze the reproductive toxicity caused by CuO NPs at low concentration (10, 50 and 100 μg/L) After 20-days exposure, the structure of zebrafish ovary and testis were impaired. Moreover, the contents of 17β-estradiol (E2) in both females and males were increased, while the contents of testosterone (T) were decreased, indicating the imbalanced sex hormones caused by CuO NPs. The expression of genes along the hypothalamic pituitary-gonad (HPG) axis, were examined with quantitative real-time PCR to further evaluate the toxic mechanisms. Meanwhile, the levels of erα/er2β and cyp19a in female zebrafishes and erα/er2β, lhr, hmgra/hmgrb, 3βhsd and 17βhsd in male zebrafishes were obviously up-regulated. While, the level of αr was obviously down-regulated in female and male zebrafishes. Thus, the obtained data uncovered that long-term exposure of CuO NPs with low dose could trigger the endocrine disorder, resulting in the disturbance of E2 and T level, inhibition of gonad development, and alteration of HPG axis genes. In brief, this study enriched the toxicological data of NPs on aquatic vertebrates and provided the theoretical support for assessing the environmental safety of NPs

Biosorption of Silver Ions by Biomass: Equilibrium, Kinetics and Thermodynamics

The freeze-dried biomass of Paecilomyces lilacinus was employed as a biosorbent for the removal of silver ions from aqueous solution. The effects of factors such as the solution pH, the initial Ag(I) ion concentration, contact time and temperature were examined. Maximum Ag(I) adsorption was obtained at pH 3.0. The pseudo-first-order, pseudo-second-order and intra-particle diffusion kinetic models were fitted to the experimental data when it was found that such data were best fitted by the pseudo-second-order kinetic model. The equilibrium experimental data were well fitted by the Langmuir model (R 2 > 0.995) and the maximum biosorption capacity at 298 K was 101.0 mmol/g. Thermodynamic parameters such as the Gibbs' free energy, ΔG 0 , the standard enthalpy, ΔH 0 , and the standard entropy, ΔS 0 , were evaluated. The results indicated that the biosorption of Ag(I) ions onto P. lilacinus biomass was spontaneous and endothermic in nature. The FT-IR analysis results indicated that amine, carboxylic and hydroxyl groups were involved in the biosorption process