Snake venom components and their applications in biomedicine

Snake envenomation is a socio-medical problem of considerable magnitude. About 2.5 million people are bitten by snakes annually, more than 100,000 fatally. However, although bites can be deadly, snake venom is a natural biological resource that contains several components of potential therapeutic value. Venom has been used in the treatment of a variety of pathophysiological conditions in Ayurveda, homeopathy and folk medicine. With the advent of biotechnology, the efficacy of such treatments has been substantiated by purifying components of venom and delineating their therapeutic properties. This review will focus on certain snake venom components and their applications in health and disease. Received 6 July 2006; received after revision 14 August 2006; accepted 28 September 2006     

Compensatory caspase activation in MPP+-induced cell death in dopaminergic neurons

Many have hypothesized that cell death in Parkinsons disease is via apoptosis and, specifically, by the mitochondrial-mediated apoptotic pathway. We tested this hypothesis using a mouse dopaminergic cell line of mesencephalic origin, MN9D, challenged with the Parkinsonism-causing neurotoxin MPP⁺ (1-methyl-4-phenylpyridinium ion). Apoptosis was the main mode of cell death when the cells were subjected to MPP⁺ treatment under serum-free conditions for 24 h. Caspase-3 and caspase-9, however, were not activated, thus indicating the existence of alternate or compensatory cell death pathway(s) in dopaminergic neuronal cells. Using caspase inhibitors, we demonstrated that these pathways involve caspase-2, –8, –6 and –7. A time-course study indicated that activation of caspase-2 and –8 occurred upstream of caspase-6 and caspase-7. Upon MPP⁺ challenge, the apoptosis-inducing factor was translocated from the mitochondria into the MN9D cytosol and nucleus. These results suggest the existence of alternative apoptotic pathways in dopaminergic neurons.Received 20 September 2004; received after revision 5 November 2004; accepted 22 November 2004     

电压门控钠离子通道:律动生命乐章的主音符

生命个体传递神经冲动时扩布的电位变化过程以动作电位发放形式为特质表征.电压门控钠离子通道 (voltage-gated sodium channels,VGSCs)是形成动作电位的核心蛋白构件,在细胞的电兴奋产生和律动中起主角作用.VGSCs决定神经元细胞的兴奋性以及从突触输入到轴突输出的信号传导过程.VGSCs也是众...     

混合式与反式Py115神经毒素对果蝇神经肌肉兴奋性接头电位的影响

Py115是一类胆碱能阻断剂(Cholinergic Blocker)有顺反异构体混合型和反式两种。本实验采用肌细胞的胞内记录法研究了这两种毒素对果蝇3龄幼虫运动神经—腹纵肌兴奋性接头电位(Excitatory Junctional Potentials简称EJPS)的影响,探讨这类胆碱能毒素对以L—谷氨酸(L—glutamate简称L—GLU)为递质的神经一肌肉接头电位的影响。结果表明:两种py115毒素都可以不可逆地阻断果蝇三龄幼虫的EJPS;阻断所需的时间取决于Py115的浓度;同一浓度下反式Py115的作用大于混合式Py115。     

Crystallization and preliminary X-ray analysis of an anti-insect toxin BmK I6 from Buthus martensii Karsch scorpion

An excitatory anti-insect toxin from BmK scorpion, named BmK I6, has been purified and crystallized recently. Two crystal forms have been obtained by using ammonium sulfate as precipitant at different pH, one of which is single crystal. Diffraction data have been collected for the single crystal on a Mar Research 345 Image Plate. The analyses of the data show that the crystal can diffract to 0.28 nm resolution and belongs to the space group C2 with unit cell parameters a = 4.65 nm, b = 8.52 nm, c = 3.26 nm, α = γ = 90° ,β = 110.5° . There are 2 molecules per asymmetric unit according to its unit cell volume and molecular weight.     

Crystallization and preliminary X-ray analysis of an anti-insect toxin BmK 16 fromButhus martensii Karsch scorpion

An excitatory anti-insect toxin from BmK scorpion, named BmK 16, has been purified and crystallized recently. Two crystal forms have been obtained by using ammonium sulfate as precipitant at different pH, one of which is single crystal. Diffraction data have been collected for the single crystal on a Mar Research 345 Image Plate. The analyses of the data show that the crystal can diffract to 0.28 nm resolution and belongs to the space group C2 with unit cell parameters a = 4.65 nm,b = 8.52 nm,c = 3.26 nm, α = γ = 90°, β = 110.5°. There are 2 molecules per asymmetric unit according to its unit cell volume and molecular weight.     

东亚钳蝎神经毒素的研究进展

蝎毒中的神经毒素是一类具有特异生物活性的多肽物质。开展对蝎神经毒素的研究是近几年国内外较关注的课题之一。东亚马氏钳蝎（ＢｕｔｈｕｓｍａｒｔｅｎｓｉＫａｒｓｃｈ，ＢｍＫ）是中国分布最广的一种。本文综述了近几年来Ｂｍｋ神经毒素的一级结构研究的一些进展概况