Voltage-gated Na+ channel (Nav channel) scorpion toxins are classified as α- and β-neurotoxins. Ts5 (α-neurotoxin) and Ts1 (β-neurotoxin) from Tityus serrulatus venom (TsV) interact with Nav channels, increasing N...Voltage-gated Na+ channel (Nav channel) scorpion toxins are classified as α- and β-neurotoxins. Ts5 (α-neurotoxin) and Ts1 (β-neurotoxin) from Tityus serrulatus venom (TsV) interact with Nav channels, increasing Na+ influx and activating voltage-dependent Ca2+ channels. This study aimed to investigate the effect of TsV, Ts1 and Ts5 on the cytosolic Ca2+ concentration ([Ca2+]C) in rat aortic smooth muscle cells. Toxins were isolated by ion exchange chromatography (Ts1) followed by RP-HPLC (Ts5). The rat aortic smooth muscle cells were isolated in Hanks buffer pH 7.4 and loaded with 5 μmol/L of Fura-2AM (45 minutes at 37℃), in order to measure [Ca2+]C by fluorescence of Fura-2/AM (ratio 340/380 nm). The fluorescence was measured in one single cell (excitation: 340 and 380 nm;emission: 510 nm). TsV (100 and 500 mg/mL) and its toxins Ts1 and Ts5 (50 and 100 mg/mL each) led to a concentration-dependent increase in [Ca2+]C. Tetrodotoxin (1 mmol/L), a Nav channel blocker, and verapamil (1 mmol/L), a voltage-operated Ca2+ channel blocker, inhibited the increase in [Ca2+]C induced by TsV (500 mg/mL). In conclusion, TsV and its toxins induce a concentration-dependent increase in [Ca2+]C that probably occurs through interaction with Nav channels, thus inducing depolarization and consequent Ca2+ influx. This assumption is based on the fact that this effect is inhibited by tetrodotoxin and verapamil, showing a direct action of TsV toxins on aorta smooth muscle cells.展开更多
Hierarchically porous single-crystalline nanosized zeolites as heterogeneous catalysts show great poten- tial in fine chemistry because they offer more rich hierarchically porous channels for the mass transfer and mol...Hierarchically porous single-crystalline nanosized zeolites as heterogeneous catalysts show great poten- tial in fine chemistry because they offer more rich hierarchically porous channels for the mass transfer and molecular diffusion. However, the synthesis of hierarchically porous nanosized zeolites generally requires the assistance of templates acting as the mesoporogens, which limits its popularity. Herein, we report a one-pot and template-free synthesis of hierarchically porous single-crystalline nanosized zeolite beta only by introducing sodium carbonate in precursor solution. The resulted sample features the extraordinary properties, including the uniform nanocrystal （200-300 nm）, high pore volume （0.65 cm3g 1） and the hierarchical pore-size distribution （e.g., 2-8 and 90-150 nm）. After slicing pro- cessing, it is interestingly found that a large number of interconnected mesopores penetrate throughout whole material, which enables the hierarchically porous nanosized zeolite beta remarkably superior cat- alytic activity than the conventional zeolite beta in condensation of henzaldehyde with ethanol at room temperature. More importantly, this one-pot sodium carbonate-assisted synthetic strategy is highly ver- satile, which has also been successfully developed to synthesize hierarchically porous nanosized single- crystalline zeolites ZSM-5 and TS.展开更多
基金supported by grants from Fundacao de Amparoa Pesquisa do Estado de Sao Paulo(FAPESP)Conselho Nacional de Desenvolvimento Cientifico e Tecnologico(CNPq).
文摘Voltage-gated Na+ channel (Nav channel) scorpion toxins are classified as α- and β-neurotoxins. Ts5 (α-neurotoxin) and Ts1 (β-neurotoxin) from Tityus serrulatus venom (TsV) interact with Nav channels, increasing Na+ influx and activating voltage-dependent Ca2+ channels. This study aimed to investigate the effect of TsV, Ts1 and Ts5 on the cytosolic Ca2+ concentration ([Ca2+]C) in rat aortic smooth muscle cells. Toxins were isolated by ion exchange chromatography (Ts1) followed by RP-HPLC (Ts5). The rat aortic smooth muscle cells were isolated in Hanks buffer pH 7.4 and loaded with 5 μmol/L of Fura-2AM (45 minutes at 37℃), in order to measure [Ca2+]C by fluorescence of Fura-2/AM (ratio 340/380 nm). The fluorescence was measured in one single cell (excitation: 340 and 380 nm;emission: 510 nm). TsV (100 and 500 mg/mL) and its toxins Ts1 and Ts5 (50 and 100 mg/mL each) led to a concentration-dependent increase in [Ca2+]C. Tetrodotoxin (1 mmol/L), a Nav channel blocker, and verapamil (1 mmol/L), a voltage-operated Ca2+ channel blocker, inhibited the increase in [Ca2+]C induced by TsV (500 mg/mL). In conclusion, TsV and its toxins induce a concentration-dependent increase in [Ca2+]C that probably occurs through interaction with Nav channels, thus inducing depolarization and consequent Ca2+ influx. This assumption is based on the fact that this effect is inhibited by tetrodotoxin and verapamil, showing a direct action of TsV toxins on aorta smooth muscle cells.
基金sponsored by the National Key Basic Research Program of China(2013CB933200)China National Funds for Distinguished Young Scientists(51225202)+2 种基金National Natural Science Foundation of China(51502330)shanghai international cooperation project(16520710200)Science Foundation for Youth Scholar of State Key Laboratory of High Performance Ceramics and Superfine Microstructures(SKL201604)
文摘Hierarchically porous single-crystalline nanosized zeolites as heterogeneous catalysts show great poten- tial in fine chemistry because they offer more rich hierarchically porous channels for the mass transfer and molecular diffusion. However, the synthesis of hierarchically porous nanosized zeolites generally requires the assistance of templates acting as the mesoporogens, which limits its popularity. Herein, we report a one-pot and template-free synthesis of hierarchically porous single-crystalline nanosized zeolite beta only by introducing sodium carbonate in precursor solution. The resulted sample features the extraordinary properties, including the uniform nanocrystal （200-300 nm）, high pore volume （0.65 cm3g 1） and the hierarchical pore-size distribution （e.g., 2-8 and 90-150 nm）. After slicing pro- cessing, it is interestingly found that a large number of interconnected mesopores penetrate throughout whole material, which enables the hierarchically porous nanosized zeolite beta remarkably superior cat- alytic activity than the conventional zeolite beta in condensation of henzaldehyde with ethanol at room temperature. More importantly, this one-pot sodium carbonate-assisted synthetic strategy is highly ver- satile, which has also been successfully developed to synthesize hierarchically porous nanosized single- crystalline zeolites ZSM-5 and TS.
