科研之友
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摘要
Cecropins are basic antibacterial peptides that have potent antimicrobial activities. We induced and purified a novel antimicrobial peptide exhibiting activity against Gram-negative bacteria from the immunized hemolymph of Hermetia illucens larvae. The immunized hemolymph was extracted, and the novel cecropin-like peptide 1 (CLP1) was purified using solid-phase extraction and reverse-phase chromatography. The purified CLP1 demonstrated a molecular weight of 4,840 Da, as determined by matrix-assisted laser desorption/ionization-time-off-light (MALDI-TOF). From analysis of CLP1 by N-terminal amino acid sequencing using Edman degradation, combined with MALDI-TOF and rapid amplification of cDNA ends-polymerase chain reaction (RACE-PCR), the amino acid sequence of the mature peptide was determined to be GWRKR VFKPVEKFGQR VRDAGVQGIAIAQQGANVLATARGGP PQQG. In NCBI BLAST, the amino acid sequence of CLP1 was found to be 60 % identical to the Drosophila melanogaster cecropin C. In silico analysis revealed that CLP1 was suggested to be part of the cecropin superfamily of AMPs characterized as cationic, linear, a-helical, and amphipathic polypeptides. Analysis of the minimal inhibitory concentration (MIC) and the minimal bactericidal concentration (MBC) showed that CLP1 exerted antibacterial effects against Gram-negative bacteria. The expression of CLP1 transcripts in several tissues after bacterial challenge was measured by quantitative real-time PCR. CLP1 expression was negligible throughout the body before immunization, and was mostly evident in the fat body after immunization.
- 出版日期2017-3
