Extraction And Purification Of Secretion From Housefly Larvae And Its Antimicrobial Character

Insects had highly effective chemical defensense system. Housefly larvae had developed humoral immunus and chemical defensense system. Antimicrobial substances were extracted from the skin of housefly larvae, pupae and the remains of the larvae feed. The attained rate respectivly was 0. 07%, 0. 02%, 0. 62%. The antimicrobial secretion could be divided into three sections, every section had antimicrobial activity. The first could be extracted by petroleum ether, the second could be extracted by ethyl alcohol, the third could dissove in water and could be separated by sephadex G-50, G200 gel filtration chromatography and carbornmethyl cellulose-1 anion-exchange chromatography and detected by A256,.The antimicrobial secretion had wide spectrum and had strong inhitory activity against germs and fungi, they could inhibit sixteen kinds of plant pathogenic germs , eight kinds of animal germs and eight kinds of plant pathogenic fungi. The abnormal hyphal grownth caused by the. substances such as swollen tips, twisted, short growth were observed.The inhibitory activity of the secretion increased with the concentration. High temprature, ultraviolet didn't affect the activity greatly. The activity decreased with the increase of temprature, but still had 80% in 100 for ten minuts. The activity first decreased, then increased and decreased with the increase of exposure in ultraviolet. Its activity in acidic and basic condition was betterthan that in neutral condition.The antimicrobial secretion also had activity on the seeds of wheat and green bean. The highest concentration 40mg/ml could inhibit the growth of sprout, and even cause the seeds rotten.