生姜辛辣部位的高效液相色谱(HPLC)指纹图谱研究

采用HPLC法分析了4个居群生姜丙酮回流-乙醚萃取物中的多酚类化合物,建立了有较好专属性的HPLC指纹图谱,比较了姜辣素含量及其得率。     

Steady-state and closed-state inactivation properties of inactivating BK channels

Calcium-dependent potassium (BK-type) Ca2+ and voltage-dependent K+ channels in chromaffin cells exhibit an inactivation that probably arises from coassembly of Slo1 alpha subunits with auxiliary beta subunits. One goal of this work was to determine whether the Ca2+ dependence of inactivation arises from any mechanism other than coupling of inactivation to the Ca2+ dependence of activation. Steady-state inactivation and the onset of inactivation were studied in inside-out patches and whole-cell recordings from rat adrenal chromaffin cells with parallel experiments on inactivating BK channels resulting from cloned alpha + beta2 subunits. In both cases, steady-state inactivation was shifted to more negative potentials by increases in submembrane [Ca2+] from 1 to 60 microM. At 10 and 60 microM Ca2+, the maximal channel availability at negative potentials was similar despite a shift in the voltage of half availability, suggesting there is no strictly Ca2+-dependent inactivation. In contrast, in the absence of Ca2+, depolarization to potentials positive to +20 mV induces channel inactivation. Thus, voltage-dependent, but not solely Ca2+-dependent, kinetic steps are required for inactivation to occur. Finally, under some conditions, BK channels are shown to inactivate as readily from closed states as from open states, indicative that a key conformational change required for inactivation precedes channel opening.     

Genbank accession #: AJ237597

Plant Molecular Biology -     

白额巨蟹蛛对红头丽蝇捕食行为的初步观察

本文首次报道了在实验条件(温度19～23 ℃、相对湿度80 %)下白额巨蟹蛛对红头丽蝇的捕食行为和捕食功能反应的初步观察结果,并用Holling-Ⅱ型功能反应模型进行拟合,白额巨蟹蛛捕食红头丽蝇的功能反应直线回归方程为:NA＝1.0031 N/(1 0.0626 N).本研究结果,可以为蜘蛛控制卫生害虫提供理论依据.