Characterization of Cimex lectularius (bedbug) defensin peptide and its antimicrobial activity against human skin microflora

详细信息    查看全文

• 作者：Akanksha Kaushal^a ; Kajal Gupta^b ; Monique L. van Hoek^c ; ^{mvanhoek@gmu.edu" class="auth_mail" title="E-mail the corresponding author}
• 关键词：Bed bug ; Defensin ; Antimicrobial peptide ; Insect antimicrobial peptides ; Skin microflora ; Antibacterial assay ; Circular dichroism ; DiSC(3)5 assay ; EC50 assay
• 刊名：Biochemical and Biophysical Research Communications
• 出版年：2016
• 出版时间：19 February 2016
• 年：2016
• 卷：470
• 期：4
• 页码：955-960
• 全文大小：789 K

文摘

Antimicrobial peptides are components of both vertebrate and invertebrate innate immune systems that are expressed in response to exposure to bacterial antigens. Naturally occurring antimicrobial peptides from evolutionarily ancient species have been extensively studied and are being developed as potential therapeutics against antibiotic resistant microorganisms. In this study, a putative Cimex lectularius (bedbug, CL) defensin is characterized for its effectiveness against human skin flora including Gram-negative and Gram-positive bacteria. The bedbug defensin (CL-defensin), belonging to family of insect defensins, is predicted to have a characteristic N-terminal loop, an α-helix, and an antiparallel β-sheet, which was supported by circular dichroism spectroscopy. The defensin was shown to be antimicrobial against Gram-positive bacteria commonly found on human skin (Micrococcus luteus, Corynebacterium renale, Staphylococcus aureus and Staphylococcus epidermidis); however, it was ineffective against common skin Gram-negative bacteria (Pseudomonas aeruginosa and Acinetobacter baumannii) under low-salt conditions. CL-defensin was also effective against M. luteus and C. renale in high-salt (MIC) conditions. Our studies indicate that CL-defensin functions by depolarization and pore-formation in the bacterial cytoplasmic membrane.