Hong Y, Truong AD, Lee J, Lee K, Kim GB, Heo KN, Lillehoj HS, Hong YH. Identification of duck liver-expressed antimicrobial peptide 2 and characterization of its bactericidal activity.
Asian-Australas J Anim Sci 2018;
32:1052-1061. [PMID:
30381731 PMCID:
PMC6601062 DOI:
10.5713/ajas.18.0571]
[Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/28/2018] [Accepted: 10/26/2018] [Indexed: 01/22/2023]
Abstract
Objective
This study was conducted to identify duck liver-expressed antimicrobial peptide 2 (LEAP-2) and demonstrate its antimicrobial activity against various pathogens.
Methods
Tissue samples were collected from 6 to 8-week-old Pekin ducks (Anas platyrhynchos domesticus), total RNA was extracted, and cDNA was synthesized. To confirm the duck LEAP-2 transcript expression levels, quantitative real-time polymerase chain reaction was conducted. Two kinds of peptides (a linear peptide and a disulfide-type peptide) were synthesized to compare the antimicrobial activity. Then, antimicrobial activity assay and fluorescence microscopic analysis were conducted to demonstrate duck LEAP-2 bactericidal activity.
Results
The duck LEAP-2 peptide sequence showed high identity with those of other avian species (>85%), as well as more than 55% of identity with mammalian sequences. LEAP-2 mRNA was highly expressed in the liver with duodenum next, and then followed by lung, spleen, bursa and jejunum and was the lowest in the muscle. Both of LEAP-2 peptides efficiently killed bacteria, although the disulfide-type LEAP-2 showed more powerful bactericidal activity. Also, gram-positive bacteria was more susceptible to duck LEAP-2 than gram-negative bacteria. Using microscopy, we confirmed that LEAP-2 peptides could kill bacteria by disrupting the bacterial cell envelope.
Conclusion
Duck LEAP-2 showed its antimicrobial activity against both gram-positive and gram-negative bacteria. Disulfide bonds were important for the powerful killing effect by disrupting the bacterial cell envelope. Therefore, duck LEAP-2 can be used for effective antibiotics alternatives.
Collapse