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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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Related in: MedlinePlus

Effects of EC5 on the growth of different bacteria.Different concentrations of peptide EC5 was added to log phase cultures of bacteria and their growth monitored after 2 h. Numbers indicate reduction in log10 CFU/ml.
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pone-0056081-g003: Effects of EC5 on the growth of different bacteria.Different concentrations of peptide EC5 was added to log phase cultures of bacteria and their growth monitored after 2 h. Numbers indicate reduction in log10 CFU/ml.

Mentions: As EC5 demonstrated features common to an antimicrobial peptide we tried to investigate whether EC5 could exert antimicrobial effect in vitro. Mid-logarithmic phase cultures of bacteria with an inoculum of 105 CFU/ml were incubated with peptide concentrations ranging from 0 to 50 µg/ml in a shaker incubator for 2 h. Subsequently the samples were plated on NA agar plates and CFU were determined. EC5 showed a reduction of 5 log10 CFU/ml of E. coli and P. aeruginosa at peptide concentrations of 12.5, 25 and 50 µg/ml as observed by absence of colonies on NA plates (Fig. 3). However it showed no activity against any of the other bacteria tested even at 50 µg/ml.


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)

Effects of EC5 on the growth of different bacteria.Different concentrations of peptide EC5 was added to log phase cultures of bacteria and their growth monitored after 2 h. Numbers indicate reduction in log10 CFU/ml.
© Copyright Policy
Related In: Results  -  Collection

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

pone-0056081-g003: Effects of EC5 on the growth of different bacteria.Different concentrations of peptide EC5 was added to log phase cultures of bacteria and their growth monitored after 2 h. Numbers indicate reduction in log10 CFU/ml.
Mentions: As EC5 demonstrated features common to an antimicrobial peptide we tried to investigate whether EC5 could exert antimicrobial effect in vitro. Mid-logarithmic phase cultures of bacteria with an inoculum of 105 CFU/ml were incubated with peptide concentrations ranging from 0 to 50 µg/ml in a shaker incubator for 2 h. Subsequently the samples were plated on NA agar plates and CFU were determined. EC5 showed a reduction of 5 log10 CFU/ml of E. coli and P. aeruginosa at peptide concentrations of 12.5, 25 and 50 µg/ml as observed by absence of colonies on NA plates (Fig. 3). However it showed no activity against any of the other bacteria tested even at 50 µg/ml.

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