Water soluble skin secretions of six common Chinese amphibians were studied for their biological and enzymatic activities.The skin secretions of Tylototriton verrucosus,Bombina maxima ,and Bufo andrewsi were f...Water soluble skin secretions of six common Chinese amphibians were studied for their biological and enzymatic activities.The skin secretions of Tylototriton verrucosus,Bombina maxima ,and Bufo andrewsi were found toxic to mice with the intraperitoneal LD 50 of 11 5?mg/kg,18 8?mg/kg,and 264?mg/kg,respectively.No acute lethal toxicities were observed for the skin secretions of Rana nigromaculata,Rana guentheri and Rana limnocharis in a dose up to 500?mg/kg.The lethal toxicities of the skin secretions of T verrucosus and B maxima to mice are in the same grade as those of Viperidae snake venoms.The toxic components in T verrucosus and B maxima skin secretions are the proteins with molecular weights ranging from 3 to 60?kDa.All the skin secretions had both proteolytic activity and trypsin inhibitory activity.The skin secretions from T verrucosus , B maxima and B andrewsi also displayed wide spectrum antimicrobial activity.On the other hand,the skin secretions from B andrewsi and B maxima showed cytotoxicity on human cancer cells.All the six samples had not significant effects on mammalian blood coagulation system.Phospholipase A 2 activity was only found in the skin secretions of T verrucosus .None of these skin secretions showed acetylcholine esterase activity.展开更多
Various kinds of biologically active peptides have previously been isolated from the skin secretions of Amolops loloensis frog,such as antimicrobial peptides,bradykinin-like peptides and algesic peptides.A novel insul...Various kinds of biologically active peptides have previously been isolated from the skin secretions of Amolops loloensis frog,such as antimicrobial peptides,bradykinin-like peptides and algesic peptides.A novel insulinotropic peptide named amolopin was identified in A.loloensis frog’s skin secretion.Its primary structure sequence was determined by Edman degradation as:FLPIVGKSLSGLSGKL-NH2.BLAST search indicates that the amino acid sequence of amolopin is quite different from other known insulin secretagogues,including mastoparan,exendins and a-latrotoxin,nor does it like incretins(e.g.glucagons like peptide-1 and glucose-dependent insulinotropic ploypeptide)either.However,amolopin shows certain structural similarity with amphibian antimicrobial temporins and vespid chemotactic peptides isolated from Vespa magnifica.Amolopin can stimulate insulin release in INS-1 cells in a dose-dependent manner.Primary investigation on its action mechanisms reveals that amolopin does not increase the influx of Ca2?.In conclusion,a novel 16-amino acid peptide with insulin-releasing activity is initially discovered from the skin secretion of A.loloensis frog.Further work is necessary to evaluate its potential as novel anti-diabetic candidate.展开更多
文摘Water soluble skin secretions of six common Chinese amphibians were studied for their biological and enzymatic activities.The skin secretions of Tylototriton verrucosus,Bombina maxima ,and Bufo andrewsi were found toxic to mice with the intraperitoneal LD 50 of 11 5?mg/kg,18 8?mg/kg,and 264?mg/kg,respectively.No acute lethal toxicities were observed for the skin secretions of Rana nigromaculata,Rana guentheri and Rana limnocharis in a dose up to 500?mg/kg.The lethal toxicities of the skin secretions of T verrucosus and B maxima to mice are in the same grade as those of Viperidae snake venoms.The toxic components in T verrucosus and B maxima skin secretions are the proteins with molecular weights ranging from 3 to 60?kDa.All the skin secretions had both proteolytic activity and trypsin inhibitory activity.The skin secretions from T verrucosus , B maxima and B andrewsi also displayed wide spectrum antimicrobial activity.On the other hand,the skin secretions from B andrewsi and B maxima showed cytotoxicity on human cancer cells.All the six samples had not significant effects on mammalian blood coagulation system.Phospholipase A 2 activity was only found in the skin secretions of T verrucosus .None of these skin secretions showed acetylcholine esterase activity.
文摘Various kinds of biologically active peptides have previously been isolated from the skin secretions of Amolops loloensis frog,such as antimicrobial peptides,bradykinin-like peptides and algesic peptides.A novel insulinotropic peptide named amolopin was identified in A.loloensis frog’s skin secretion.Its primary structure sequence was determined by Edman degradation as:FLPIVGKSLSGLSGKL-NH2.BLAST search indicates that the amino acid sequence of amolopin is quite different from other known insulin secretagogues,including mastoparan,exendins and a-latrotoxin,nor does it like incretins(e.g.glucagons like peptide-1 and glucose-dependent insulinotropic ploypeptide)either.However,amolopin shows certain structural similarity with amphibian antimicrobial temporins and vespid chemotactic peptides isolated from Vespa magnifica.Amolopin can stimulate insulin release in INS-1 cells in a dose-dependent manner.Primary investigation on its action mechanisms reveals that amolopin does not increase the influx of Ca2?.In conclusion,a novel 16-amino acid peptide with insulin-releasing activity is initially discovered from the skin secretion of A.loloensis frog.Further work is necessary to evaluate its potential as novel anti-diabetic candidate.
