Antimicrobial peptides of an anti-lipopolysaccharide factor, epinecidin-1, and hepcidin reduce the lethality of Riemerella anatipestifer sepsis in ducks.
Antimicrobial peptides (AMPs) are effective against a wide range of microbes, but still no research results have reported their use in duck disease therapy. Riemerella anatipestifer (RA) is a Gram-negative bacterium which infects ducks and causes very significant economic losses. The minimum inhibitory concentrations (MICs) of epinecidin-1 for the tested RA strains ranged 6.25-50microg/ml, those of the SALF55-76 cyclic peptide ranged 12.5-25microg/ml, those of the SALF55-76 linear peptide ranged 6.25-25microg/ml, those of hepcidin TH1-5 ranged 25-400microg/ml, and those of hepcidin TH2-3 ranged 100-400microg/ml. The antimicrobial activities of these peptides were confirmed by transmission electron microscopy which showed that RA disruption of the outer membrane brought about cell death. In addition, pretreatment, co-treatment, and post-treatment with peptides were all effective in promoting a significant decrease in duck mortality and decreasing the number of infectious bacteria. A quantitative RT-PCR was performed to survey levels of gene expressions of Mn superoxide dismutase in the brain, lipoprotein lipase in the liver, and H5 histone in the spleen induced in response to bacterial infection and an injection of the AMPs in experiments with the duck, Cairina moschata. Our results indicated that the rescue of ducks by the peptides and the behavior of the peptides, which was like an enhancer in immunology, may involve regulation of the expressions of these genes. Collectively, these peptides reduced the mortality in ducks during bacterial challenge, suggesting that AMPs have the potential to serve as therapeutic drugs for use against bacterial infectious diseases in ducks.
Marine Research Station, Institute of Cellular and Organismic Biology, Academia Sinica, 23-10 Dahuen Road, Jiaushi, Ilan 262, Taiwan.
Chieh-Yu
CY
Pan
The-Yuan
TY
Chow
Chao-Yuan
CY
Yu
Chang-You
CY
Yu
Jian-Chyi
JC
Chen
Jyh-Yih
JY
Chen
D000818:Animals; D023181:Antimicrobial Cationic Peptides / Q000138:chemical synthesis / Q000737:chemistry / Q000627:therapeutic use*; D004372:Ducks; D041965:Flavobacteriaceae / Q000472:pathogenicity* / Q000648:ultrastructure; D045826:Flavobacteriaceae Infections / Q000188:drug therapy / Q000382:microbiology; D064451:Hepcidins; D008070:Lipopolysaccharides / Q000037:antagonists & inhibitors*; D008099:Liver / Q000378:metabolism / Q000382:microbiology; D046529:Microscopy, Electron, Transmission; D011201:Poultry Diseases / Q000188:drug therapy* / Q000382:microbiology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D018805:Sepsis / Q000188:drug therapy* / Q000382:microbiology
D023181:Antimicrobial Cationic Peptides; D064451:Hepcidins; D008070:Lipopolysaccharides