This work forwards new insights into the risk-assessment of multi-walled carbon-nanotubes (MWCNTs) while analysing the role of quantum-mechanical interactions between the electrons in the adsorption of probe compounds and biomolecules by MWCNTs. For this, the quantitative models are developed using quantum-chemical descriptors and their electron-correlation contribution. The major quantum-chemical factors contributing to the adsorption are found to be mean polarizability, electron-correlation energy, and electron-correlation contribution to the absolute electronegativity and LUMO energy. The proposed models, based on only three quantum-chemical factors, are found to be even more robust and predictive than the previously known five or four factors based linear free-energy and solvation-energy relationships. The proposed models are employed to predict the adsorption of biomolecules including steroid hormones and DNA bases. The steroid hormones are predicted to be strongly adsorbed by the MWCNTs, with the order: hydrocortisone > aldosterone > progesterone > ethinyl-oestradiol > testosterone > oestradiol, whereas the DNA bases are found to be relatively less adsorbed but follow the order as: guanine > adenine > thymine > cytosine > uracil. Besides these, the developed electron-correlation based models predict several insecticides, pesticides, herbicides, fungicides, plasticizers and antimicrobial agents in cosmetics, to be strongly adsorbed by the carbon-nanotubes. The present study proposes that the instantaneous inter-electronic interactions may be quite significant in various physico-chemical processes involving MWCNTs, and can be used as a reliable predictor for their risk assessment.

Although numerous studies have shown that hypoxia affects cortisol and aldosterone production in vivo, the underlying molecular mechanisms regulating the steroidogenic genes of these steroid hormones are still poorly known. MicroRNAs are post-transcriptional regulators that control diverse biological processes and this study describes the identification and validation of the hypoxia-inducible microRNA, miR-10b, as a negative regulator of the CYP11B1 and CYP11B2 steroidogenic genes in H295R human adrenocortical cells. Using the human TaqMan Low Density miRNA Arrays, we determined the miRNA expression patterns in H295R cells under normoxic and hypoxic conditions, and in cells overexpressing the human HIF-1α. Computer analysis using three in silico algorithms predicted that the hypoxia-inducible miR-10b molecule targets CYP11B1 and CYP11B2 mRNAs. Gene transfection studies of luciferase constructs containing the 3′-untranslated region of CYP11B1 or CYP11B2, combined with miRNA overexpression and knockdown experiments provide compelling evidence that CYP11B1 and CYP11B2 mRNAs are likely targets of miR-10b.

The aim of the present study was to verify if cocaine, at environmental concentrations, influences the endocrine system of the European eel. Silver eels (a stage of the eel life cycle preparing the fish for the oceanic reproductive migration) were exposed to a nominal cocaine concentration of 20 ng/l during 30 days; at the same time, control, carrier, and postexposure recovery groups were made. The effects of cocaine were observed in (1) brain dopamine content, (2) plasma catecholamine levels (dopamine, norepinephrine, and epinephrine), (3) pituitary–adrenal axis activity [plasma adrenocorticotropic hormone (ACTH), corticosterone, cortisol, and aldosterone levels], and (4) pituitary–thyroid axis activity [plasma thyroid-stimulating hormone (TSH), triiodothyronine, and thyroxine levels]. In the treated group, brain dopamine, plasma catecholamines, cortisol, and TSH levels were higher, whereas ACTH, corticosterone, and triiodothyronine levels were lower than controls. In the postexposure recovery group, brain dopamine, plasma dopamine and epinephrine, and thyroxine levels further increased, whereas plasma norepinephrine, cortisol, and corticosterone levels were similar to treated values. Finally, ACTH and TSH were similar, whereas triiodothyronine levels were lower than controls. Aldosterone levels were unaffected by cocaine exposure. The results of the present study show that cocaine, at environmental concentrations, behaves like an endocrine disruptor changing brain dopamine and plasma catecholamine levels and the activity of pituitary–adrenal/thyroid axes. Since the endocrine system plays a key role in the metabolic and reproductive processes of the eel, our results suggest that environmental cocaine could be considered another cause for the decline in the European eel.

There have been growing concerns and uncertainty about reports attributing the metabolic disturbance induced by a commercial formulation of glyphosate-based herbicide to its active ingredient. We therefore compared the effects of Roundup Original® and its active ingredient glyphosate on some hypothalamic-pituitary-adrenal (HPA) hormones and oxidative stress markers, biochemical and hematological profiles in 56 adult male albino rats randomly assigned to seven treatments of eight rats per treatment. The rats were orally exposed to Roundup Original® and its active ingredient daily at 3.6 mg/kg body weight (bw), 50.4 and 248.4 mg/kgbw of glyphosate equivalent concentrations for 12 weeks, while control treatment received distilled water. Serum concentrations of corticosterone, adrenocorticotropic hormone, aldosterone and concentration of oxidative stress marker, biochemical and hematological profiles in the blood were determined. Concentrations of corticosterone and aldosterone were significantly higher (p < 0.05) in rats treated with Roundup in a dose-dependent manner. Reduced glutathione concentration, catalase, and butyrylcholinesterase activities reduced significantly in rats treated with Roundup relative to those treated with the active ingredient. Lipid peroxidation was observed in rats treated with Roundup. Biochemical and hematological profiles of rats treated with Roundup were significantly altered (p < 0.05). However, significant changes in only acid phosphatase, lactase dehydrogenase, bilirubin, and white blood cells in rats treated with the active ingredient at 50.4 mg/kg were observed. The severe metabolic disturbance and stress observed in rats treated with the commercial formulation of Roundup herbicide may not be associated with the mild changes induced by the active ingredient.