Isolation, Purification And Activity Study Of A Novel Antimicrobial Peptide From The Skin Of Wild Rana Nigromaculata

Antimicrobial peptides are a kind of micromolecular peptides with immuno activities that are synthesized by ribosome and secreted by gland cells, and are coded by special genes. AMPs is first named to describe a kind of peptides with broad spectrum antibiosis activities that were found in the hemolymph of insects. After Boman, Sweden scientist, isolated AMPs from pupa of tiancan for the first time, some peptides with familiar functions were found in animals, human being, plant as well as fungus. Nowadays, the conception of AMPs is not located merely in antibiosis activities, some AMPs have the ability to kill fungus, parasites, viruses, and tumor cells, and some AMPs even can inhibit the proliferation of HIV-1. It is very interesting that AMPs could dramatically kill multidrug resistant strains.There is no doubt that the foundation of antibiosis of traditional means is very great and have saved many people and animals. Until the80s of20centuries, almost all infected illness were conquered by the use of antibiotics. Unfortunately, because the abuse of antibiotics and the special structure of pathogenic microorganism, more and more strains achieved drug resistant abilities. The foundation of AMPs inject new blood to the research of new antibiotic drugs, especially some AMPs can dramatically kill multidrug resistant strains and tumor cells but not normal cells. There is no doubt that AMPs is the best substitution of antibiotics. Recently, the number of AMPs is rising every year, Enfuvirtide is the best represent, it can suppress HIV getting into cells. It is thus evident that it is very hard to estimate the research potentiality and the commercial values, and it will be a good news to our life and healthy.Amphibians, as the interim species between fishes and reptiles, which is skin outward without any crustaceans, living in a surrounding always changes sharply, and It will provides the favorable environment for pathogenic microorganisms to grow, but the infection can be resist by itself. It has shown that the acquired immune of amphibians is weak definitely, and the dominant immune strategies is innate physical immunological barrier and antimicrobial peptides defense system. There are lots of skin glands in forgs, grain glands especially, and more kinds of antimicrobial peptides secreted than any other amphibians. And there is a huge race of frogs all over the world,which means that the amount of antimicrobial peptides is extraordinarily considerable. More evidence proves that the content of antimicrobial peptides in Amphibians is100000times as in the mammalian.The experiment animals are Rana nigromaculata captured in wild. By conducting electric to stimulate the skin of frogs, to make the secretion with antimicrobial abilities secreted from the glands of frog skins, and then purified by RP-HPLC. After purified several times, we obtain two high purity antimicrobial peptides named AMP-1and AMP-2by Edman degradation sequencing, and the two AMPs show strong inhibitory action to S.aureus ATCC25923and Escherichia coli ATCC25922, slight inhibitory action to MRSA, Besides this, they also show inhibitory action to MCF-7and slight haemolysis.