The Preliminary Studies On Antimicrobial Peptides Isolated From Musca Domestica Vicina

The preliminary studies on antimicrobial peptidesisolated from Musca domestict, vicinaAbstractIn this research, two antimicrobial peptides were detected in the extraction of the Musca domestica vicina larvae when the larvae were injured with a needle and then infected by Staph vlococcus auerus. These peptides were isolated by a three steps protocol including heating, CM- cellulose cation-exchange chromatography, and Sephadex G-50 gel filtration. The molecular weight of these peptides are 4kD and 9.6kD respectively. They can kill Staphylococcus auerus effectively, but no effect on Bacillus sub tills, Escherchia coil and Pseudornonas aeruginosa. The pept ides also can inhibit the proliferation of stomach cancer cells MGC8O-3 and BGC-823, breast cancer cells MCF-7 and lung cancer cells SPC-A-l in vitro. When the concentrations lower than 62.5ug/mL, their inhibition rates are under 23%, but when the concentrations rise to 125ug/mL, all of theinhibitionratesincreaseabout20%.Whentheirconcentrations are as high as 250ug/mL, the inhibition rates all higher than 67%. We also found the larvae of Afusca domestica vicina without inducing also can produce the antimicrobial peptides. The diameter of inhibition zone of the extraction of the larvae feeding by bran is 8mm, but that of the larvae feeding by pig dejection is 15mm.