The prosurvival role of autophagy in Resveratrol-induced cytotoxicity in human U251 glioma cells

Abstract Background Previous study reported that resveratrol has anti-tumor activity. In this study, we investigated the involvement of autophagy in the resveratrol-induced apoptotic death of human U251 glioma cells. Methods The growth inhibition of U251 cells induced by resveratrol was assessed with methyl thiazolyl tetrazolium (MTT). The activation of autophagy and proapoptotic effect were characterized by monodansylcadaverine labeling and Hoechst stain, respectively. Mitochondrialtransmembrane potential (ΔΨm) was measured as a function of drug treatment using 5,5',6,6'-tetrachloro-1,1',3,3'-tetraethylbenzimidazolylcarbocyanine iodide (JC-1). The role of autophagy and apoptosis in the resveratrol-induced death of U251 cells was assessed using autophagic and caspase inhibitors. Immunofluorescence, flow cytometry, and Western blot analysis were used to study the apoptotic and autophagic mechanisms. Results Methyl thiazolyl tetrazolium (MTT) assays indicated that resveratrol decreased the viability of U251 cells in a dose- and time-dependent manner. Flow cytometry analysis indicated that resveratrol increased cell population at sub-G1 phase, an index of apoptosis. Furthermore, resveratrol-induced cell death was associated with a collapse of the mitochondrial membrane potential. The pan-caspase inhibitor Z-VAD-fmk suppressed resveratrol-induced U251 cell death. Resveratrol stimulated autophagy was evidenced by punctuate monodansylcadaverine(MDC) staining and microtubule-associated protein light chain 3 (LC3) immunoreactivty. Resveratrol also increased protein levels of beclin 1 and membrane form LC3 (LC3-II). Autophagy inhibitors 3-methylademine (3-MA) and bafilomycin A1 sensitized the cytotoxicity of resveratrol. Conclusion Together, these findings indicate that resveratrol induces autophagy in human U251 glioma cells and autophagy suppressed resveratrol-induced apoptosis. This study thus suggests that autophagy inhibitors can increase the cytotoxicity of resveratrol to glioma cells.</p

Identification of four genes associated with cutaneous metastatic melanoma

Cutaneous melanoma is an aggressive cancer with increasing incidence and mortality rates worldwide. Metastasis is one of the primary elements that influence the prognosis of patients with cutaneous melanoma. This study aims to clarify the potential mechanism underlying the low survival rate of metastatic melanoma and to search for novel target genes to improve the survival rate of patients with metastatic tumors

Production of Biodiesel Catalyzed by Candida rugosa

The synthesis between palmitic acid and methanol was carried out in a w/o reverse microemulsion prepared from the mixture of dodecylbenzenesulfonic acid (DBSA)/isooctane/water. Box-Behnken design was adopted to evaluate the effect of significant factors on the methyl palmitate yield and response surface methodology (RSM), which was employed to optimize the process parameters in the esterification. The conditions that showed optimal results for methyl palmitate preparation were: 3.33 w0 ([H2O]/[surfactant]), 4.2 h reaction time, 5:1 methanol/acid molar ratio, and 130 mg g-1 lipase ([lipase]/[acid]) concentration. The following verification experiment obtained a result of 97% in almost total agreement with the expected value (98%). The kinetic constants of the model were determined by experiments at 40 °C with initial concentrations of 0.025-0.25 mol L-1 palmitic acid and 0.025-0.3 mol L-1 methanol in the microemulsion system. The kinetic studies showed that the reaction obeyed the Ping-Pong bi-bi mechanism with inhibition by methanol

Photoelectrochemical Catalysis of Fluorine‐Doped Amorphous TiO 2

© 2020 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim In this paper, we report a fluorine-doped amorphous titanium dioxide nano-tube-array (a-TNT−F) catalyst for photo-electrochemical water splitting. The a-TNT−F can be activated by the full-spectrum sunlight with the advantages of high efficiency, low cost, easily prepared and rich natural sources. X-ray diffraction, scanning electron microscopy, transmission electron microscopy and other tests confirm the nano-tube array structure of the a-TNT−F. The photo-electrochemical water splitting tests of a-TNT−F are conducted under the condition of dark, visible light and modulated sunlight. Results show that the water can be split into hydrogen and oxygen with the electrolysis voltage of 1.2 V under the irradiation of modulated sunlight, which is even lower than the theoretical voltage (1.23 V) of water splitting. The amorphous structure and doped fluorine greatly decrease the polarization of oxygen evolution on the electrode. The catalytic performance of the annealed a-TNT−F surpasses that of RuO2. We also ascertain the feasibility of combining a-TNT−F with solar cell for water splitting in natural environment. The a-TNT−F has great potential to be high performance catalyst for water splitting and has a bright future for large scale applications

Photoelectrochemical Catalysis of Fluorine-Doped Amorphous TiO2 Nanotube Array for Water Splitting

© 2020 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim In this paper, we report a fluorine-doped amorphous titanium dioxide nano-tube-array (a-TNT−F) catalyst for photo-electrochemical water splitting. The a-TNT−F can be activated by the full-spectrum sunlight with the advantages of high efficiency, low cost, easily prepared and rich natural sources. X-ray diffraction, scanning electron microscopy, transmission electron microscopy and other tests confirm the nano-tube array structure of the a-TNT−F. The photo-electrochemical water splitting tests of a-TNT−F are conducted under the condition of dark, visible light and modulated sunlight. Results show that the water can be split into hydrogen and oxygen with the electrolysis voltage of 1.2 V under the irradiation of modulated sunlight, which is even lower than the theoretical voltage (1.23 V) of water splitting. The amorphous structure and doped fluorine greatly decrease the polarization of oxygen evolution on the electrode. The catalytic performance of the annealed a-TNT−F surpasses that of RuO2. We also ascertain the feasibility of combining a-TNT−F with solar cell for water splitting in natural environment. The a-TNT−F has great potential to be high performance catalyst for water splitting and has a bright future for large scale applications

Soybean milk derived carbon intercalated with reduced graphene oxide as high efficient electrocatalysts for oxygen reduction reaction

Exploring high-performance and low-cost metal-free oxygen reduction reaction (ORR) catalysts from biomass-derived materials is vital to the development of novel energy conversion devices such as fuel cells, etc. Herein, nitrogen-enriched soybean milk derived carbon (BDC/rGO-HT-NH3) intercalated with reduced graphene oxide (rGO) electrocatalyst is prepared via one-pot hydrothermal synthesis method followed with nitridation by NH3. The resultant catalyst with high surface area, good conductivity and high content of N (9.4 at.%) shows high electrocatalytic activity towards ORR in alkaline medium, which mainly happens through the direct 4-electron pathway. The onset potential of BDC/rGO-HT-NH3 catalyzed ORR is 0.96 V vs RHE, which is only 0.11 V lower than that of the commercial Pt/C (20 wt%) catalyst. In addition, the BDC/rGO-HT-NH3 catalyst shows superior long-term running durability. The desirable catalytic performances enable the facile synthesis approach of BDC/rGO-HT-NH3 to be a promising methodology for transforming other biomass materials to N-enriched carbon based materials as low-cost and environmental friendly catalysts for ORR. (C)2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved

MOFs-derived core-shell Co3Fe7@Fe2N nanopaticles supported on rGO as high-performance bifunctional electrocatalyst for oxygen reduction and oxygen evolution reactions

© 2020 Elsevier Ltd Exploring stable and highly efficient bifunctional electrocatalysts for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is critical for the novel energy conversion and storage devices including fuel cells and metal-air batteries. Herein, the core-shell structured Co3Fe7@Fe2N nanoparticles supported on reduced graphene oxide (rGO) nanosheets (Co3Fe7@Fe2N/rGO) is designed though the simple annealing of MOFs. The as-fabricated samples present an excellent electrocatalytic performance for ORR and OER due to the synergistic effect of electrode materials. The Co3Fe7@Fe2N/rGO exhibits an onset potential of 0.98 V (vs. Reversible hydrogen electrode), peak current intensity of 1.531 A g−1 and long-term stability for ORR, which is close to that of the benchmark Pt/C (20%) in 0.1 M KOH. It also shows good oxygen evolution reaction (OER) performance with an overpotential of 371 mV (at 10 mA cm−2). When used as a bifunctional air electrode in Zn-air batteries, the core-shell materials enabled an excellent mass power density of 60 W cm−2 g−1 at 0.57 V and stable cycling performance for over 100 cycles

Cathepsin L activated by mutant p53 and Egr-1 promotes ionizing radiation-induced EMT in human NSCLC

Abstract Background Ionizing radiation (IR) is one of the major clinical therapies of cancer, although it increases the epithelial-mesenchymal transition (EMT) of non-small cell lung cancer (NSCLC), unexpectedly. The cellular and molecular mechanisms underlying this role are not completely understood. Methods We used NSCLC cell lines as well as tumor specimens from 78 patients with NSCLC to evaluate p53, Cathepsin L (CTSL) and EMT phenotypic changes. Xenograft models was also utilized to examine the roles of mutant p53 (mut-p53) and CTSL in regulating IR-induced EMT of NSCLC. Results Expression of CTSL was markedly increased in human NSCLC tissues with mutant p53 (mut-p53), and p53 mutation positively correlated with metastasis of NSCLC patients. In human non-small cell lung cancer cell line, H1299 cells transfected with various p53 lentivirus vectors, mut-p53 could promote the invasion and motility of cells under IR, mainly through the EMT. This EMT process was induced by elevating intranuclear CTSL which was regulated by mut-p53 depending on Early growth response protein-1 (Egr-1) activation. In the subcutaneous tumor xenograft model, IR promoted the EMT of the cancer cells in the presence of mut-p53, owing to increase expression and nuclear transition of its downstream protein CTSL. Conclusion Taken together, these data reveal the role of the mut-p53/Egr-1/CTSL axis in regulating the signaling pathway responsible for IR-induced EMT

Iodine-Catalyzed C–H Amidation and Imination at the 2α-Position of 2,3-Disubstituted Indoles with Chloramine Salts

A novel iodine-catalyzed amidation and imination at the 2α-position of 2,3-disubstituted indoles in the presence of chloramine salts with high regioselectivity has been achieved. The protocol is applicable to a wide range of substrates to deliver the corresponding 2α-nitrogen-containing indole derivatives. Furthermore, to demonstrate the synthetic value of this established transformation, a concise assembly of the bridged tetracyclic framework of akuammiline alkaloids from the 2α-amidated product has been accomplished in five steps

Synergistic Catalytic Effect of Hollow Carbon Nanosphere and Silver Nanoparticles for Oxygen Reduction Reaction

© 2020 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim Developing low-cost and high-performance catalysts for oxygen reduction reaction (ORR) is critical for fuel cell applications. In this study, hollow carbon nano-spheres (HCNS) are synthesized by a hydrothermal method and used as the support for silver nano-particles (Ag@HCNS) as the ORR catalyst. The morphology of Ag@HCNS is investigated by the transmission electron microscopy (TEM), scanning electron microscopy (SEM) and other methodologies. Results show that the silver nanoparticles with a diameter from 3 to 6 nm are evenly distributed on the surface of HCNS. The catalytic performances of the HCNS and Ag@HCNS for ORR are investigated by cyclic voltammetry, linear sweeping voltammetry, rotating disc and rotating ring disc electrode tests. The synergistic effect between HCNS and Ag nanoparticles plays the major role on the high catalytic activity of Ag@HCNS for ORR. The onset potential of Ag@HCNS (0.82 V v.s. RHE) catalyzed ORR is close to that of Pt/C catalyst. In addition, the reaction kinetics study shows that the Ag@HCNS catalyzed ORR major proceeds through 4-electron style. This paper promotes the understanding of the happening mechanism of ORR on the surface of novel carbon supported metal nanoparticles