[Analysis of antibacterial-relative proteins and peptides in housefly larvae].

Objective: To study the antibacterial-relative proteins and peptides in housefly larvae.

Methods: Third-instar larvae of housefly were treated with different methods including pricking, pricking with bacteria, heating and ultrasonication and were extracted respectively after 6 h, 16 h, 24 h, 48 h, 65 h. After liquid phase assay, the antibacterial-relative proteins and peptides were confirmed with stepwise regression analysis.

Results: The four treatments could all induce antibacterial substances. Among these induced proteins, X17 (20 kDa), X16 (22 kDa) had activity against Staphylococcus aureus and Bacillus subtilis, but X22 (13 kDa), X20 (16 kDa), X12 (26 kDa) had activity only against either Staphylococcus aureus or Bacillus subtilis. X7 (37 kDa), X5 (44 kDa) had negative contribution to antibacterial activity.

Conclusion: Many antibacterial-relative proteins and peptides which cooperate and establish a whole resisting system will begin to be translated or be translated more.