Deletion of HAPS_2096 Increases Sensitivity to Cecropin B in <b><i>Haemophilus parasuis</i></b>

Abstract

Cecropin B (CB) is a very effective natural antimicrobial peptide that has shown great potential for future antimicrobial drug development. HAPS_2096 is a Haemophilus parasuis gene that encodes the periplasmic substrate-binding protein of an ATP-binding cassette-type amino acid transporter. In this research, we constructed and verified an HAPS_2096 deletion mutant and a complementary HAPS_2096 mutant of H. parasuis JS0135. A bactericidal assay revealed that the HAPS_2096 deletion mutant was significantly more sensitive than the wild-type strain to 0.25-0.5 µg/ml CB. However, the gene complementation alleviated the CB sensitivity of the mutant. Immunoelectron microscopy observation following a 30-min treatment with a sublethal concentration of CB (0.25 μg/ml) revealed more extensive morphological damage in the mutant strain than in the wild-type strain. Hence, our results suggest that the HAPS_2096 gene contributes to H. parasuis resistance to CB.

The antimicrobial effect of a novel peptide LL-1 on Escherichia coli by increasing membrane permeability

“…When antimicrobial peptides enter bacteria, they may combine with bacterial nucleic acid, which results in bacteria losing their normal replication and transcription functions causing abnormal expression of the proteins required for the growth and development of bacteria. In addition, antimicrobial peptide may interact with bacterial protein, resulting in changes of protein structure, inactivation of many bacterial enzymes, and disorder of metabolism, causing bacteria to die [19][20][21].…”