The cDNA encoding a variant of α bungarotoxin was cloned from the venom glands of Bungarus multicinctus by RT PCR.The deduced protein precursor contained a 21 amino acid signal peptide and a following 74 amino ...The cDNA encoding a variant of α bungarotoxin was cloned from the venom glands of Bungarus multicinctus by RT PCR.The deduced protein precursor contained a 21 amino acid signal peptide and a following 74 amino acid mature protein.The signal peptide is very similar to those of short chain neurotoxins,κ neurotoxins and cardiotoxins.The amino acid sequence of the mature protein is identical to α bungarotoxin (V31),a minor variant of α bungarotoxin identified by protein sequencing technique.Furthermore,the cDNA encoding the deletion precursor of α bungarotoxin was also cloned.By use of pMAL p2,the variant was overexpressed in E coli as a soluble fusion protein and purified by sepharose 6B amylose affinity chromatography,which was confirmed by western blotting with the antisera agai nst α bungarotoxin.The recombinant variant was achieved after digestion by factor X a.It displayed about 1/6 in vivo toxicity of natural α bungarotoxin.The successful cloning and functional expression of α bungarotoxin provided a basis for the future study of structure function of long neurotoxins.展开更多
Neuromuscular junction is the main target for snakebites, which venoms act depending on the snake genus for paralyzing the prey （neurotoxicity） or for facilitating the digestion processes of the victim （myotoxicity...Neuromuscular junction is the main target for snakebites, which venoms act depending on the snake genus for paralyzing the prey （neurotoxicity） or for facilitating the digestion processes of the victim （myotoxicity）, and also as a defense mechanism against predators. In the present study, a mouse neuromuscular apparatus was used for testing the hexane fraction of Casearia gossypiosperma plant, that showed the better antiophidian ability than dichloromethane, ethyl acetate and methanol fractions, against the irreversible paralysis induced by two, Bothrops jararacussu （Bjssu, 40 μg/mL） and Crotalus durissus terrificus （Cdt, 10 μg/mL） snake venoms. All fractions were obtained by liquid-liquid partition from the C. gossypiosperma hydroalcoholic lyophilized extract. The preliminary chromatographic profile of this plant showed phenols and flavonols as active constituents, whereas hexane fraction expressed mainly 13-sitosterol and quercetin. In spite of hexane fraction protection （≌95% and 48% against Bjssu and Cdt, respectively）, isolately, only quercetin protected against the blockade-induced by Bjssu venom （65.5%）. This study showed that hexane fraction acts against these snake venoms by a synergistic phytocomplex mechanism.展开更多
This paper deals with the Mangal Kavyas of Bengal, folk epics arising out of an oral tradition practiced by rural women. The female deities to whom these epics are devoted, like the snake goddess Manasa, are also part...This paper deals with the Mangal Kavyas of Bengal, folk epics arising out of an oral tradition practiced by rural women. The female deities to whom these epics are devoted, like the snake goddess Manasa, are also part of the folk tradition, far removed from the Hindu pantheon of gods or the Vedic ways of worship and are related to the particular fears of village life. There is therefore, a de-mythologized version of these deities represented in these epics, a crystallization of the desires, wants, and ways of life of the rural population through the figure of the goddess, a version these village women can readily empathize with, making these epics rich in social documentation of contemporary village life.展开更多
基金the"95"great program of Chinese Academy of Sciences! (KY95 1-A1-3 0 1-0 2 )
文摘The cDNA encoding a variant of α bungarotoxin was cloned from the venom glands of Bungarus multicinctus by RT PCR.The deduced protein precursor contained a 21 amino acid signal peptide and a following 74 amino acid mature protein.The signal peptide is very similar to those of short chain neurotoxins,κ neurotoxins and cardiotoxins.The amino acid sequence of the mature protein is identical to α bungarotoxin (V31),a minor variant of α bungarotoxin identified by protein sequencing technique.Furthermore,the cDNA encoding the deletion precursor of α bungarotoxin was also cloned.By use of pMAL p2,the variant was overexpressed in E coli as a soluble fusion protein and purified by sepharose 6B amylose affinity chromatography,which was confirmed by western blotting with the antisera agai nst α bungarotoxin.The recombinant variant was achieved after digestion by factor X a.It displayed about 1/6 in vivo toxicity of natural α bungarotoxin.The successful cloning and functional expression of α bungarotoxin provided a basis for the future study of structure function of long neurotoxins.
文摘Neuromuscular junction is the main target for snakebites, which venoms act depending on the snake genus for paralyzing the prey （neurotoxicity） or for facilitating the digestion processes of the victim （myotoxicity）, and also as a defense mechanism against predators. In the present study, a mouse neuromuscular apparatus was used for testing the hexane fraction of Casearia gossypiosperma plant, that showed the better antiophidian ability than dichloromethane, ethyl acetate and methanol fractions, against the irreversible paralysis induced by two, Bothrops jararacussu （Bjssu, 40 μg/mL） and Crotalus durissus terrificus （Cdt, 10 μg/mL） snake venoms. All fractions were obtained by liquid-liquid partition from the C. gossypiosperma hydroalcoholic lyophilized extract. The preliminary chromatographic profile of this plant showed phenols and flavonols as active constituents, whereas hexane fraction expressed mainly 13-sitosterol and quercetin. In spite of hexane fraction protection （≌95% and 48% against Bjssu and Cdt, respectively）, isolately, only quercetin protected against the blockade-induced by Bjssu venom （65.5%）. This study showed that hexane fraction acts against these snake venoms by a synergistic phytocomplex mechanism.
文摘This paper deals with the Mangal Kavyas of Bengal, folk epics arising out of an oral tradition practiced by rural women. The female deities to whom these epics are devoted, like the snake goddess Manasa, are also part of the folk tradition, far removed from the Hindu pantheon of gods or the Vedic ways of worship and are related to the particular fears of village life. There is therefore, a de-mythologized version of these deities represented in these epics, a crystallization of the desires, wants, and ways of life of the rural population through the figure of the goddess, a version these village women can readily empathize with, making these epics rich in social documentation of contemporary village life.
