锂盐的作用机制及临床应用研究进展

锂是人体内的一种微量元素且以化合物的形式广泛存在于自然界。作为一种古老的治疗精神疾病方面的药物,锂盐被用来治疗双相情感障碍已超过60年,而现在锂盐在临床上表现出来的新应用已经越来越引起医学界的广泛重视。现代研究表明,锂盐是一种强大的糖原合成酶激酶-3(GSK-3β)抑制剂,锂盐除对脑细胞过度活动起抑制作用外,还具有营养神经和保护神经、抗炎、抗氧化、抗癌、免疫调节以及对甲状腺功能亢进的治疗作用。锂盐化学结构相对简单,而且目前人们对锂盐的使用经验及对锂离子的血药浓度监测手段已日趋成熟,所以锂盐具有相当好的临床应用前景,未来更进一步加大对锂盐的临床应用及作用机制的研究力度。现就锂盐新发现的作用机制及临床应用作一综述。     

豚鼠心肌α-肾上腺素受体反应的可能机制——增强细胞外钙离子内流

同时记录豚鼠心室肌细胞动作电位、零期最大去极化速率和心肌条的收缩幅度,观察了α-肾上腺素受体激动剂或增加细胞外钙离子浓度([Ca~(2 )]_0)的作用,以及在肾上腺素受体或钙通道阻断剂存在下这些作用的变化,试图分析α-受体与钙通道的可能关系。我们看到甲氧胺与增加[Ca~(2 )]_0都可使动作电位峰值增加、平台期电位高抬、收缩幅度增高,甲氧胺的效应可被戊脉胺阻断,而增加[Ca~(2 )]_0的效应可被酚妥拉明阻断。酚妥拉明同戊脉安两者的效应有近似之处,心得安对甲氧胺和增加[Ca~(2 )]_0效应无显著影响。由此认为:心肌α-肾上腺素受体的电生理效应与缓慢正性变力作用很可能是通过激活钙通道,增加细胞外钙离子的慢内流来实现的。     

携带杀白细胞素基因金黄色葡萄球菌的研究进展

杀白细胞素(Panton-Valentine leukocidin,PVL)是金葡菌产生的重要外毒素之一,PVL在其感染所致的坏死性皮肤损害和坏死性肺炎等疾病中起重要作用,并且能在社区和医院传播。现在国内外对PVL阳性金葡菌的研究日益重视,本文就其感染的致病机制、感染状况、检测方法和防治措施等问题研究作一陈述。     

阿拉善高原2种荒漠植物根系构型及生态适应性特征

根系构型决定了植物对资源的吸收方式，根系构型的变化是植物对环境的生态适应和有效生存策略。在阿拉善高原西南缘红砂（Reaumuria soongarica）-珍珠猪毛菜（Salsola passerina）混生群落采用传统挖掘法收集两种植物根系，基于量化的根系形态指标，利用几何拓扑学及分形理论分析了根系构型特征，探讨了该地区2种植物对干旱生境的生态适应策略。结果表明：红砂和珍珠猪毛菜根系均以水平分布占优，根系浅层化分布明显，混生的两种植物占据不同的生态位；2种荒漠植物均具有较大的比根长（SRL）和比表面积（SRA），红砂SRL=21.3 cm/g，SRA=7.6 cm²/g，珍珠SRL=22.4 cm/g，SRA=6.5 cm²/g，有利于水分和养分的获取；红砂根系拓扑指数（TI）、修正拓扑参数（q_a和q_b）分别为0.86、0.52、0.49，珍珠猪毛菜对应参数分别为0.93、0.76、0.73，表明2种植物根系均趋向于鱼尾形分支结构；根系分形维数值（FD_红=1.488、FD_珍=1.422）较小，而分形丰度值（lgK_红=1.855、lgK_珍=1.774）较大，表明2种植物分支相对简单，但空间拓展能力强，有利于对营养空间的占有。上述特征可能是阿拉善西南缘红砂-珍珠猪毛菜群落2种荒漠植物植物对干旱贫瘠生境的重要生态适应策略。     

Fractal root system of Melica przewalskyi along different aspect in degraded grassland

Aims Fractal root system is phenotypic plasticity result of plant root architecture to respond to environmental heterogeneity, may reflect the growth strategy of plants to adapt to environmental conditions. Our objective was to explore the relationship between root fractal dimension and fractal abundance of fractal root system of Melica przewalskyi population in response to aspect variation in the northwest of China. Methods The study site was located in a degraded alpine grassland on the northern slope in Qilian Mountains, Gansu Province, China. Survey and sampling were carried out at 40 plots which were set up along four slope aspects transects with 20 m distance between adjacent plots. Handheld GPS was used to determine the elevation, longitude and latitude of each plot. ArcGIS was used to set up digital elevation model (DEM). Community traits were investigated and six individuals roots of M. przewalskyi were collected randomly at each plot. The samples were cleaned and divided into different organs, then scanning the root with the Win-RHIZO for measurements of fractal dimension and fractal abundance in laboratory, and their biomass were then measured after being dried at 80 °C in an oven. Important findings With the slope aspect turned from north to east, west, and south, the density, height and soil moisture content of the plant community displayed a pattern of initial decline, the height, density, root fractal abundance of M. przewalskyi increased and the root fractal dimension decreased. The root fractal dimension was negatively associated with the fractal abundance in all aspects, but the relationship varied along the slope aspects gradient; there was a highly significant negative correlation (p < 0.01) between the root fractal dimension and fractal abundance at north slope and south slope aspect, whereas the correlation only reached a significant level (p < 0.05) at the east slope aspect and west slope aspect; indicating that there is a trade-off between the root fractal dimension and fractal abundance. In addition, when the slope aspect changed from north to east, west and south, the standardized major axis (SMA) slope of the regression equation in the scaling relationships between root fractal dimension and fractal abundance increased (p < 0.05), indicating that the roots of M. przewalskyi at the droughty southern slope have less branch and more sparse in the same soil volume of root exploitation and utilization. Consequently, the resource allocation pattern on reasonable trade-off between root fractal dimension and fractal abundance in different slope aspect of M. przewalskyi, reflects the relationship between the income and the cost of construction of plant root architecture.     

我国水稻耐盐功能基因研究取得重大进展

中科院上海生科院植物生理生态所植物分子遗传国家重点实验室林鸿宣研究员及其博士生任仲海、高继平等与美国加州大学伯克利分校栾升教授及其助手李乐攻博士进行合作，在水稻重要农艺性状功能基因研究上取得突破性进展，成功克隆了与水稻耐盐相关的数量性状基因SKC1，并阐明了该基因的生物学功能和作用机理。相关论文已在线发表于国际顶级遗传学杂志《自然一遗传学））（Nature Genetics），并将刊登在10月份期的《自然．遗传学》上。