由蠶血中分離昆蟲之抗菌蛋白，其中發現對於格蘭氏陰性菌可產生抗菌反應，對於格蘭氏陽性菌，如金黃色葡萄球菌及枯草桿菌，亦能有效被抑制，但對於酵母菌則 無抑菌反應。其中Cecropin可以被初純化，利用親和性曾析法，可以得到數條專一性band，且具有強抗菌反應。經由設計引子對，使用PCR增殖 Cecropin B，Cecropin D特異性抗菌蛋白基因，產生特異之DNA 帶，195 bp及335bp PCR產物，但在野蠶體內卻無法產生特異之DNA帶，在經免疫之家蠶體內，可以產生cecropin B、Cecropin D特異之核酸，並嘗試利用TA clone方法做定序，分析其中之差異，並且檢測其專一性與靈敏度。In response to an injection of bacteria, lepidopteran insects produce several kinds of proteins with antibacterial activity. We investigated the antibacterial activity of the hemolymph from Bombyx mori against gram-negative or positive bacteria. Cecropin, inducible antibacterial peptides were purified by simple affinity chromatography from immunized larval hemolymph of the silk worm, Bombyx mori. The two major cecropins were sequenced. And was compared the different between the cecropin B and cecropin D. In the present work, we surveyed the antibacterial activity of the hemolymph against two of gram-positive bacteria, S. aureus, Bacillus subtillus and gram-negative bacteria, E. coli. The partial purified peptide showed antibacterial activity against both gram-negative and positive bacterial.
