Evaluation of Developmental Toxicity and Oxidative Stress Caused by Zinc Oxide Nanoparticles in Zebra Fish Embryos/ Larvae.

Zinc oxide nanoparticles (ZnO NPs) are used in various fields, including biological ones. ZnO NPs are eventually disposed of in the environment where they may affect natural systems, and there is no international law to regulate their manufacture, usage, and disposal. Hence, this present study is carried out to synthesise a more non-toxic and bioactive ZnO NPs from the marine algae Sargassum polycystum. The ZnO NPs were biologically produced using the marine algae Sargassum polycystum. The dynamic light scattering result describes that synthesised particles' average size is about 100 nm in diameter. Transmission electron microscopy (TEM) analysis demonstrated the rod-like morphology of ZnO NPs. Fourier tranform-infrared spectroscopy (FT-IR) results revealed the presence of functional groups in ZnO NPs. The selected area electron diffraction (SAED) results strongly suggested the ZnO NPs crystallinity. ZnO NPs surface morphology and compositions were identified by scanning electron microscopy (SEM- EDX) values. To analyse the toxicity of synthesised nanoparticles, zebra fish larvae were used, which involved subjecting embryos to various ZnO NPs concentrations at 1 hpf and analysing the results at 96 hpf. The 60 and 80 ppm sub-lethal doses were chosen for further studies based on the LC50 (82.23 ppm). In the ZnO NPs-treated groups, a significant slowdown in pulse rate and a delay in hatching were seen, both of which impacted the embryonic processes. A teratogenic study revealed a dose-dependent increase in the incidence of developmental deformities in the treated groups. Along with increased oxidants and a corresponding reduction in antioxidant enzymes, Na+ K+-ATPase and AChE activity changes were seen in ZnO NPs-treated zebra fish larvae groups. The apoptosis process was increased in ZnO NPs-treated groups revealed by acridine orange staining. These results indicate that the green synthesis process cannot mitigate the oxidative stress induced by ZnO NPs on oxidative signalling.

Comparative toxicity of UV-filter Octyl methoxycinnamate and its photoproducts on zebrafish development.

In the present study, we explored the adverse effects of Octyl methoxycinnamate (OMC), and its photoproducts, namely 2-ethylhexanol (2-EH) and 4-methoxybenzaldehyde (4-MBA) on the developmental stages of zebrafish using various biomarkers such as developmental toxicity, oxidative stress, antioxidant response, neurotoxicity and histopathological changes. The 96 h effective concentrations (EC50) of OMC, 2-EH and 4-MBA were found to be 64.0, 34.0 and 3.5 µg/mL, respectively in the embryo toxicity test. Embryos exposed to the EC50 of OMC, 2-EH and 4-MBA showed time-dependent increases in the malformation, heart rate and hatching delay. The lipid peroxidation (LPO) level was significantly (p < 0.05) increased and both induction and inhibition of SOD, CAT, GPx and GST activities were observed in the zebrafish embryos exposed to OMC, 2-EH and 4-MBA. GSH activity was significantly (p < 0.05) decreased in the highest exposure groups, when compared with the control. AChE activity was increased in lower concentrations of OMC, 2-EH and 4-MBA exposed embryos whereas, the activity was found to be decreased in highest concentration. Moreover, the histopathological studies showed severe damage to the muscle fibers and yolk sac regions of the larvae with 4-MBA treatment. The photoproduct 4-MBA has the highest toxic effect, followed by 2-EH and OMC. Our results provide useful insights into the impacts of OMC and its photoproducts on zebrafish development.

New insight into NANOG: A novel therapeutic target for ovarian cancer (OC).

Cancer incidence, metastasis, drug resistance and recurrence are still the critical issues of oncological diseases especially Ovarian cancer (OC). It has been suggested that drug resistance and disease relapse are the main causes for the aggressive nature of OC. There is an immediate need to develop novel strategies to understand the mechanism to overcome chemoresistance. Nanog has been found to regulate stemness like cells inside the cancer cells that are termed as Cancer Stem Cells (CSCs). These cells show high self-renewal capacity with a peculiar potential in tumour initiation, heterogeneity, progression, metastasis, recurrence, radiotherapy and multi drug resistance. Recent studies have demonstrated that Nanog, a key transcription factor for pluripotency, has been playing a major role in chemoresistance. In this review, we address the functions of Nanog in both normal and cancer cells, how Nanog is involved in OC tumorigenesis and chemoresistance. This review also highlights the methods that are used for targeting Nanog as a remedy for treating OC. Thus, through this review, we predict that these concepts will open new avenues of research in ovarian cancer stem cells, and would propose Nanog as a target to improve the outcome of chemotherapy.

Electrical Properties of Conductive Cotton Yarn Coated with Eosin Y Functionalized Reduced Graphene Oxide.

This study reports the fabrication and investigation of the electrical properties of two types of conductive cotton yarns coated with eosin Y or eosin B functionalized reduced graphene (RGO) and bare graphene oxide (GO) using dip-coating method. The surface morphology of the conductive cotton yarn coated with reduced graphene oxide was observed by Scanning Electron Microscope (SEM). Due to the strong electrostatic attractive forces, the negatively charged surface such as the eosin Y functionalized reduced graphene oxide or bare GO can be easily coated to the positively charged polyethyleneimine (PEI) treated cotton yarn. The maximum current for the conductive cotton yarn coated with eosin Y functionalized RGO and bare GO with 20 cycles repetition of (5D + R) process was found to be 793.8 µA and 3482.8 µA. Our results showed that the electrical conductivity of bare GO coated conductive cotton yarn increased by approximately four orders of magnitude with the increase in the dipping cycle of (5D+R) process.

Toxicological effects of clofibric acid and diclofenac on plasma thyroid hormones of an Indian major carp, Cirrhinus mrigala during short and long-term exposures.

In the present investigation, the toxicity of most commonly detected pharmaceuticals in the aquatic environment namely clofibric acid (CA) and diclofenac (DCF) was investigated in an Indian major carp Cirrhinus mrigala. Fingerlings of C. mrigala were exposed to different concentrations (1, 10 and 100µgL(-1)) of CA and DCF for a period of 96h (short term) and 35 days (long term). The toxic effects of CA and DCF on thyroid hormones (THs) such as thyroid stimulating hormone (TSH), thyroxine (T4) and triiodothyronine (T3) levels were evaluated. During the short and long-term exposure period TSH level was found to be decreased at all concentrations of CA (except at the end of 14(th) day in 1 and 10µgL(-l) and 21(st) day in 1µgL(-l)) whereas in DCF exposed fish TSH level was found to be increased when compared to control groups. T4 level was found to be decreased at 1 and 100µgL(-l) of CA exposure at the end of 96h. However, T4 level was decreased at all concentrations of CA and DCF during long-term (35 days) exposure period. Fish exposed to all concentrations of CA and DCF had lower level of T3 in both the treatments. These results suggest that both CA and DCF drugs induced significant changes (P<0.01 and P<0.05) on thyroid hormonal levels of C. mrigala. The alterations of these hormonal levels can be used as potential biomarkers in monitoring of pharmaceutical drugs in aquatic organisms.

Strong quantum confinement effects in kesterite Cu2ZnSnS4 nanospheres for organic optoelectronic cells.

X-ray photoelectron spectra, X-ray diffraction patterns, scanning electron microscopy images, and high-resolution transmission electron microscopy images showed that the as-prepared samples were Cu2ZnSnS4 (CZTS) nanospheres with a kesterite phase. Ultraviolet-visible absorption spectra for the CZTS nanospheres with an average crystallite size of 3.26 nm showed that the absorption edge corresponding to the energy gap shifted to the higher energy side due to the quantum confinement within the CZTS nanoparticles. Current-density measurements showed that the power conversion efficiency (0.952%) of the organic photovoltaic cells with CZTS nanospheres was much higher than that (0.120%) of the cells without CZTS nanospheres.

A Rising Cancer Prevention Target of RSK2 in Human Skin Cancer.

RSK2 is a p90 ribosomal S6 kinase family (p90(RSK)) member regulating cell proliferation and transformation induced by tumor promoters such as epithelial growth factor (EGF) and 12-O-tetradecanoylphorbol-13-acetate. This family of p90(RSK) has classified as a serine/threonine kinase that respond to many growth factors, peptide hormones, neurotransmitters, and environmental stresses such as ultraviolet (UV) light. Our recent study demonstrates that RSK2 plays a key role in human skin cancer development. Activation of RSK2 by EGF and UV through extracellular-activated protein kinases signaling pathway induces cell cycle progression, cell proliferation, and anchorage-independent cell transformation. Moreover, knockdown of RSK2 by si-RNA or sh-RNA abrogates cell proliferation and cell transformation of non-malignant human skin keratinocyte, and colony growth of malignant melanoma (MM) cells in soft agar. Importantly, activated and total RSK2 protein levels are highly detected in human skin cancer tissues including squamous cell carcinoma, basal-cell carcinoma, and MM. Kaempferol and eriodictyol are natural substances to inhibit kinase activity of the RSK2 N-terminal kinase domain, which is a critical kinase domain to transduce their activation signals to the substrates by phosphorylation. In this review, we discuss the role of RSK2 in skin cancer, particularly in activation of signaling pathways and potent natural substances to target RSK2 as chemopreventive and therapeutic agents.