Cloning of two novel P-III class metalloproteinases from Trimeresurus stejnegeri venom gland

Hemorrhagic toxins are widely distributed in viperid and crotalid snake venoms. Envenomation of Trimeresurus stejnegeri, a member of Crotalidae family, caused potent systemic and local hemorrhage. Up to now, there is no report on hemorrhage toxins from th

肝素钠的生产及其存在的问题和解决的方法(III)——无蛋白品和精品的生产

从技术路线、原料控制和设备设施等方面对肝素钠无蛋白品和精品的生产进行了论述，并就如何提高品质收率和目前存在的一些问题进行探讨。

鳜鱼视觉特性及其对捕食习性适应的研究III．视觉对猎物运动和形状的反应

作者采用行为学方法测定了伏击型凶猛鱼类鳜鱼视觉对猎物运动和形状特征的反应特性。鳜鱼对３种不同体形饵料鱼有最强的跟踪反应和攻击反应，对虾则有较强的跟踪反应而几乎没有攻击反应，对蜻蜒幼虫仅有不强的跟踪反应而完全没有攻击反应。它对低速（ｖ≤５ｃｍ／ｓ）一连续和等间歇不连续运动的饵料鱼有较强的跟踪反应和攻击反应，对中速和高速（ｖ≥１０ｃｍ／ｓ）连续运动的饵料鱼有最强的跟踪反应而几乎没有或完全没有攻击反应，对中速和高速等间歇不连续运动的饵料鱼则有最强的跟踪反应和最强的攻击反应。它对不连续运动的ａ、ｂ、ｃ、ｄ、ｅ、ｆ

Response of Microcystis to copper stress - Do phenotypes of Microcystis make a difference in stress tolerance?

To elucidate the role of phenotype in stress-tolerant bloom-forming cyanobacterium Microcystis, two phenotypes of M. aeruginosa-unicellular and colonial strains were selected to investigate how they responded to copper stress. Flow cytometry (FCM) examination indicated that the percents of viable cells in unicellular and colonial Microcystis were 1.92-2.83% and 72.3-97.51%, respectively, under 0.25 mg l(-1) copper sulfate treatment for 24 h. Upon exposure to 0.25 mg l(-1) copper sulfate, the activities of antioxidative enzyme, such as superoxide dismutase (SOD) and catalase (CAT), were significantly increased in colonial Microcystis compared to unicellular Microcystis. Meanwhile, the values of the photosynthetic parameters (F-v/F-m, ETRmax and oxygen evolution rate) decreased more rapidly in unicellular Microcystis than in colonial Microcystis. The results indicate that colonial Microcystis has a higher endurance to copper than unicellular Microcystis. This suggests that the efficient treatment concentration of copper sulfate as algaecides will be dependent on the phenotypes of Microcystis. (C) 2006 Elsevier Ltd. All rights reserved.

Simultaneous determination of chromium(VI) and chromium(III) of bioavailable fraction in bottom mud by flow injection-atomic absorption spectroscopy

A rapid and sensitive method for separation and determination of Cr(VI) and Cr(III) in bottom mud of lake by flow injection on-line preconcentrtion system and GFAAS was developed. The available Cr(VI) and Cr(III) were extracted by HOAc or EDTA + NH4 NO3 and adsorbed simultaneously by an anion and a cation resin microclummn and then eluted simultaneously by 2 mol/L NH4 NO3 + 0.05 mol/L ascorbate and 2 mol/L H2SO4, respectively. The elution was performed for 50 s after adsorption for 2 min, and the efficiencies of elution were 85.4% - 94.8% and 96.7% - 106% for Cr(VI) and Cr(M) respectively. The detection limits of the method were 0.9 mu g/L and 2.7 mu g/L with relative standard deviations of 3.5% and 6.4% for the determination of Cr(VI) and Cr(III) in sample, respectively.