氨基葡萄糖硫酸钠盐的制备及其性质

以氨基葡萄糖盐酸盐为原料,通过甲醇钠方法制备氨基葡萄糖硫酸钠盐。氨基葡萄糖盐酸盐先与甲醇钠反应生成氨基葡萄糖碱,再与三氧化硫反应,得白色粉末状产品。经物理和化学分析,其[α]     

植物硒转运蛋白的研究进展

硒是哺乳动物、细菌等许多生物的必需微量元素,也是植物生长发育的有益元素。植物主要吸收土壤中的硒酸盐和亚硒酸盐,经进一步代谢成为人类所需硒的直接或间接来源。研究表明,植物主要利用硫酸盐转运蛋白吸收硒酸盐,而吸收亚硒酸盐的方式还不太清楚。最近的研究结果发现,水孔蛋白及阴离子通道蛋白等参与亚硒酸盐的吸收,且受到多种因素调控,如呼吸抑制剂、代谢抑制剂、pH值、硝酸盐、磷酸盐及谷胱甘肽等。对近几年植物硒转运蛋白的研究结果进行了总结,并对未来的研究方向进行了展望。     

硫酸锌对酵母细胞的毒性作用

【目的】研究硫酸锌对酵母细胞的毒性作用,为揭示高浓度锌的毒性作用机理提供依据。【方法】以模式生物酵母细胞为材料,在YPD培养基中添加终浓度为0,0.5,1,3,5和10 mmol/L的硫酸锌进行毒性试验。缓解组为抗氧化剂AsA、NO清除剂c-PTIO和Ca~(2+)螯合剂EGTA分别与0.5或5 mmol/L硫酸锌同时作用。培养一定时间后,采用分光光度法、美蓝染色法和流式细胞术,研究硫酸锌对酵母细胞生长、细胞死亡率及胞内ROS、NO和Ca~(2+)水平的影响。【结果】低浓度硫酸锌(0.5 mmol/L)促进酵母细胞生长,而高浓度硫酸锌(1～10 mmol/L)抑制酵母细胞生长,诱导细胞死亡,且细胞死亡率随着硫酸锌浓度升高和胁迫时间延长而逐渐升高。酵母细胞经5 mmol/L硫酸锌胁迫12或24 h后,胞内ROS、NO和Ca~(2+)水平均显著高于对照组;但加入对应抗氧化剂AsA、NO清除剂c-PTIO和Ca~(2+)螯合剂EGTA后,酵母细胞死亡率均显著低于硫酸锌单独处理组。【结论】高浓度硫酸锌可诱导酵母细胞死亡,在此过程中ROS、NO和Ca~(2+)水平显著提高,从而造成毒性。     

BARIUM SULFATE BRONCHOGRAPHY IN HORSES

Barium sulfate bronchograms were performed on four 454-kg (1000-lb), adult, mixedbreed horses. Approximately 100 ml of 100% w/v premixed barium sulfate suspension was insufflated into a caudodorsal portion of one lung. Excellent bronchograms were obtained through six generations of bronchial divisions. Bronchograms of diagnostic quality were present for at least 30 minutes. Radiographs at 24 hours showed that most of the barium had been removed from the lung. At 48 hours, tiny barium nodules were essentially all that remained. One hundred and thirty milliliters of barium sulfate initially resulted in overfilling of the bronchial tree and prolonged retention of the contrast medium. Six weeks after bronchography, histopathologic examination of the perfused fixed lungs of two horses showed a very mild inflammatory response to the barium. One of the four horses received two barium sulfate bronchograms. This horse was observed and found to be free of any side effects for 15 months after the second bronchogram.     

气体水合物储存甲烷促进技术研究

气体水合物储气技术是世界上正在研究开发的天然气储存新技术.针对含表面活性剂水溶液体系中甲烷水合物的形成过程进行了试验研究,发现微量的表面活性剂可以使甲烷水合物在静止的系统中快速形成,并且可以提高气体水合物储存甲烷的能力.在300 mg/L十二烷基硫酸钠水溶液中,在0.9℃、5.54 MPa时,甲烷水合物储气量达到162.63 m3/m3,是理想储气量的90%.     

绵羊实验性钼中毒研究——Ⅲ.硫酸盐对体内钼、铜、铁状态的影响

日摄食钼250ppm[15mg/(kg·d)]的成年绵羊,加喂硫酸钠7g/d能显著减少其血浆、被毛及组织中的钼蓄积,显著增加脾、肝、肾等组织的铁含量;而单纯摄入高钼则对体内铁状态无显著影响。硫酸盐对摄食高钼绵羊体内铜状态的影响与单纯投钼羊类似,表现为肝、肾等组织铜、血浆总铜以及铜蓝蛋白氧化酶(CP)活性增加;对血浆铜的组分构成具有显著影响,表现为降低三氯醋酸(TCA)不溶铜而升高TCA可溶铜。在实验期间,加喂硫酸盐并未引起钼诱导的铜缺乏。     

Heparanase - a novel regulator for cell and matrix interactions

Dynamic interactions between cells and underlying extracellular matrices are crucial for development, maintenance of cellular function, and response of tissure to injury and infection. Heparan sulfate proteoglycans (HSPG) are found in extracelular matrices and on the surface of most nuclrarated cells,and play critical roles in cell-cell and cell-matrix signal transduct ion by binding many molecules, such as growth factors and cytokines. Most of the biological properties of HSPG are conferred by heparan sulfate side chains, which can be degraded by heparanase. Changes of heparanase expression and activity may affect the biological processes above, which enables extravasation of inflammation cells, metastasis and neoangiogenesis of tumor cells invasion.