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A peptide derived from phage display library exhibits antibacterial activity against E. coli and Pseudomonas aeruginosa.

Sainath Rao S, Mohan KV, Atreya CD - PLoS ONE (2013)

Bottom Line: Emergence of drug resistant strains to currently available antibiotics has resulted in the quest for novel antimicrobial agents.The peptide was highly active against gram-negative organisms and showed significant bactericidal activity against E. coli and P. aeruginosa resulting in a reduction of 5 log(10) CFU/ml.Thus this study demonstrates that peptides identified to bind to bacterial cell surface through phage-display screening may additionally aid in identifying and developing novel antimicrobial peptides.

View Article: PubMed Central - PubMed

Affiliation: Section of Cell Biology, Laboratory of Cellular Hematology, Division of Hematology, Center for Biologics Evaluation and Research, US Food and Drug Administration, Bethesda, Maryland, United States of America.

ABSTRACT
Emergence of drug resistant strains to currently available antibiotics has resulted in the quest for novel antimicrobial agents. Antimicrobial peptides (AMPs) are receiving attention as alternatives to antibiotics. In this study, we used phage-display random peptide library to identify peptides binding to the cell surface of E. coli. The peptide with sequence RLLFRKIRRLKR (EC5) bound to the cell surface of E. coli and exhibited certain features common to AMPs and was rich in Arginine and Lysine residues. Antimicrobial activity of the peptide was tested in vitro by growth inhibition assays and the bacterial membrane permeabilization assay. The peptide was highly active against gram-negative organisms and showed significant bactericidal activity against E. coli and P. aeruginosa resulting in a reduction of 5 log(10) CFU/ml. In homologous plasma and platelets, incubation of EC5 with the bacteria resulted in significant reduction of E. coli and P. aeruginosa, compared to the peptide-free controls. The peptide was non-hemolytic and non-cytotoxic when tested on eukaryotic cells in culture. EC5 was able to permeabilize the outer membrane of E. coli and P. aeruginosa causing rapid depolarization of cytoplasmic membrane resulting in killing of the cells at 5 minutes of exposure. The secondary structure of the peptide showed a α-helical conformation in the presence of aqueous environment. The bacterial lipid interaction with the peptide was also investigated using Molecular Dynamic Simulations. Thus this study demonstrates that peptides identified to bind to bacterial cell surface through phage-display screening may additionally aid in identifying and developing novel antimicrobial peptides.

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Killing kinetics of EC5 at different concentrations.A. E. coli ATCC 700928, B. E. coli ATCC 25922, C. P. aeruginosa, ATCC 12121, D. P. aeruginosa ATCC 27853. The curve represents surviving cell concentrations plotted against time.
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pone-0056081-g004: Killing kinetics of EC5 at different concentrations.A. E. coli ATCC 700928, B. E. coli ATCC 25922, C. P. aeruginosa, ATCC 12121, D. P. aeruginosa ATCC 27853. The curve represents surviving cell concentrations plotted against time.

Mentions: Time-kill kinetic studies of EC5 was comparable to polymyxin B and exhibited most rapid bactericidal activity against E. coli ATCC (700928; 25922) and P. aeruginosa ATCC (12121; 27853) (Fig. 4) with complete inhibition after 5 min incubation with the peptide and showed no regrowth until 24 hrs. EC5 showed bactericidal activity in a dose-dependent manner. MBC concentration of 8 µg/ml showed complete killing of E. coli while growth inhibitory concentration of 4 µg/ml showed reduction of 2–3 log10 CFU/ml at around 45 min of exposure to the peptide. Control peptide with no antimicrobial activity was used as negative control.


A peptide derived from phage display library exhibits antibacterial activity against E. coli and Pseudomonas aeruginosa.

Sainath Rao S, Mohan KV, Atreya CD - PLoS ONE (2013)

Killing kinetics of EC5 at different concentrations.A. E. coli ATCC 700928, B. E. coli ATCC 25922, C. P. aeruginosa, ATCC 12121, D. P. aeruginosa ATCC 27853. The curve represents surviving cell concentrations plotted against time.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3569419&req=5

pone-0056081-g004: Killing kinetics of EC5 at different concentrations.A. E. coli ATCC 700928, B. E. coli ATCC 25922, C. P. aeruginosa, ATCC 12121, D. P. aeruginosa ATCC 27853. The curve represents surviving cell concentrations plotted against time.
Mentions: Time-kill kinetic studies of EC5 was comparable to polymyxin B and exhibited most rapid bactericidal activity against E. coli ATCC (700928; 25922) and P. aeruginosa ATCC (12121; 27853) (Fig. 4) with complete inhibition after 5 min incubation with the peptide and showed no regrowth until 24 hrs. EC5 showed bactericidal activity in a dose-dependent manner. MBC concentration of 8 µg/ml showed complete killing of E. coli while growth inhibitory concentration of 4 µg/ml showed reduction of 2–3 log10 CFU/ml at around 45 min of exposure to the peptide. Control peptide with no antimicrobial activity was used as negative control.

Bottom Line: Emergence of drug resistant strains to currently available antibiotics has resulted in the quest for novel antimicrobial agents.The peptide was highly active against gram-negative organisms and showed significant bactericidal activity against E. coli and P. aeruginosa resulting in a reduction of 5 log(10) CFU/ml.Thus this study demonstrates that peptides identified to bind to bacterial cell surface through phage-display screening may additionally aid in identifying and developing novel antimicrobial peptides.

View Article: PubMed Central - PubMed

Affiliation: Section of Cell Biology, Laboratory of Cellular Hematology, Division of Hematology, Center for Biologics Evaluation and Research, US Food and Drug Administration, Bethesda, Maryland, United States of America.

ABSTRACT
Emergence of drug resistant strains to currently available antibiotics has resulted in the quest for novel antimicrobial agents. Antimicrobial peptides (AMPs) are receiving attention as alternatives to antibiotics. In this study, we used phage-display random peptide library to identify peptides binding to the cell surface of E. coli. The peptide with sequence RLLFRKIRRLKR (EC5) bound to the cell surface of E. coli and exhibited certain features common to AMPs and was rich in Arginine and Lysine residues. Antimicrobial activity of the peptide was tested in vitro by growth inhibition assays and the bacterial membrane permeabilization assay. The peptide was highly active against gram-negative organisms and showed significant bactericidal activity against E. coli and P. aeruginosa resulting in a reduction of 5 log(10) CFU/ml. In homologous plasma and platelets, incubation of EC5 with the bacteria resulted in significant reduction of E. coli and P. aeruginosa, compared to the peptide-free controls. The peptide was non-hemolytic and non-cytotoxic when tested on eukaryotic cells in culture. EC5 was able to permeabilize the outer membrane of E. coli and P. aeruginosa causing rapid depolarization of cytoplasmic membrane resulting in killing of the cells at 5 minutes of exposure. The secondary structure of the peptide showed a α-helical conformation in the presence of aqueous environment. The bacterial lipid interaction with the peptide was also investigated using Molecular Dynamic Simulations. Thus this study demonstrates that peptides identified to bind to bacterial cell surface through phage-display screening may additionally aid in identifying and developing novel antimicrobial peptides.

Show MeSH
Related in: MedlinePlus