关键词: 黑腹果蝇, 抗真菌肽, 原核表达, 可溶性表达, 抗真菌活性

Abstract: Drosomycin (Drs) is the first insect antifungal peptide from Drosophila melanogaster which showed a broad activity against filamentous fungi but no activity to bacteria. Besides the Drs, there are six gene sequences of Drs isoforms in the genome of D. melanogaster. Among them, only the activity of Drosomycin-like C (Drs-lC) was close to Drs. The soluble expression of the antifungal peptide genes Drs and Drs-lC may be applied in the preservation of agricultural products such as fruits and vegetables. In this paper, the genes of Drs and Drs-lC were respectively inserted into the fusion vector pThiohis A containing thioredoxin (Trx) and solubly expressed after the recombinant vectors were transformed into TOP10. The conditions of the expression including the starting concentration of the bacteria induced, the inductive concentration of IPTG and the incubation time after induction were optimized. The results showed that the fusion proteins, Trx-Drs and Trx-Drs-lC, were expressed as soluble proteins. The soluble expression level of Trx-Drs in the supernate amounted to 22% of the total proteins of bacteria. The expressed products of fusion proteins were purified by Ni-NTA. The results of antifungal activity detection indicated that the fusion proteins, Trx-Drs and Trx-Drs-lC, showed obvious activity against five of the eight tested fungi.

Key words: Drosophila melanogaster, antifungal peptide, prokaryotic expression, soluble expression, antifungal activity