title: Novel phospholipase A2 inhibitors from python serum are potent peptide antibiotics.
abstract: Antimicrobial peptides (AMPs) play a vital role in defense against resistant bacteria. In this study, eight different AMPs synthesized from Python reticulatus serum protein were tested for bactericidal activity against various Gram-positive and Gram-negative bacteria (Staphylococcus aureus, Burkholderia pseudomallei (KHW and TES strains), and Proteus vulgaris) using a disc-diffusion method (20 μg/disc). Among the tested peptides, phospholipase A2 inhibitory peptide (PIP)-18[59-76], β-Asp65-PIP[59-67], D-Ala66-PNT.II, and D60,65E-PIP[59-67] displayed the most potent bactericidal activity against all tested pathogens in a dose-dependent manner (100-6.8 μg/ml), with a remarkable activity noted against S. aureus at 6.8 μg/ml dose within 6 h of incubation. Determination of minimum inhibitory concentrations (MICs) by a micro-broth dilution method at 100-3.125 μg/ml revealed that PIP-18[59-76], β-Asp65-PIP[59-67] and D-Ala66-PNT.II peptides exerted a potent inhibitory effect against S. aureus and B. pseudomallei (KHW) (MICs 3.125 μg/ml), while a much less inhibitory potency (MICs 12.5 μg/ml) was noted for β-Asp65-PIP[59-67] and D-Ala66-PNT.II peptides against B. pseudomallei (TES). Higher doses of peptides had no effect on the other two strains (i.e., Klebsiella pneumoniae and Streptococcus pneumoniae). Overall, PIP-18[59-76] possessed higher antimicrobial activity than that of chloramphenicol (CHL), ceftazidime (CF) and streptomycin (ST) (30 μg/disc). When the two most active peptides, PIP-18[59-76] and β-Asp65-PIP[59-67], were applied topically at a 150 mg/kg dose for testing wound healing activity in a mouse model of S. aureus infection, the former accelerates faster wound healing than the latter peptide at 14 days post-treatment. The western blot data suggest that the topical application of peptides (PIP-18[59-67] and β-Asp65-PIP[59-67]) modulates NF-kB mediated wound repair in mice with relatively little haemolytic (100-1.56 μg/ml) and cytotoxic (1000-3.125 μg/ml) effects evident on human cells in vitro.
authors.affiliation: Venom and Toxin Research Programme, Department of Anatomy, MD10, Yong Loo Lin School of Medicine, National University Health System (NUHS), National University of Singapore, Singapore 117597; Department of Microbiology, MD4, Yong Loo Lin School of Medicine, National University Health System (NUHS), National University of Singapore, Singapore 117597; Department of Physiology, Centre for Life Sciences, NUHS, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117456. Electronic address: rperumalsamy@yahoo.co.uk.
authors.forename: Ramar Perumal
authors.initials: RP
authors.lastname: Samy
authors.affiliation: Venom and Toxin Research Programme, Department of Anatomy, MD10, Yong Loo Lin School of Medicine, National University Health System (NUHS), National University of Singapore, Singapore 117597.
authors.forename: Maung Maung
authors.initials: MM
authors.lastname: Thwin
authors.affiliation: Integrated Toxicology Division, US Army Medical Research Institute of Infectious Diseases, Fort Detrick, Maryland 21702-5011, USA; Department of Biology, Wilson College, 1015 Philadelphia Avenue, Chambersburg, PA 17201, USA.
authors.forename: Brad G
authors.initials: BG
authors.lastname: Stiles
authors.affiliation: Department of Basic Pharmaceutical Sciences, School of Pharmacy, University of Louisiana at Monroe, Monroe, LA 71291, USA.
authors.forename: Seetharama
authors.initials: S
authors.lastname: Satyanarayana-Jois
authors.affiliation: Department of Botany and Microbiology, College of Science, King Saud University, Riyadh 11451, Saudi Arabia.
authors.forename: Arunachalam
authors.initials: A
authors.lastname: Chinnathambi
authors.affiliation: Department of Botany and Microbiology, College of Science, King Saud University, Riyadh 11451, Saudi Arabia.
authors.forename: M E
authors.initials: ME
authors.lastname: Zayed
authors.affiliation: Department of Botany and Microbiology, College of Science, King Saud University, Riyadh 11451, Saudi Arabia.
authors.forename: Sulaiman Ali
authors.initials: SA
authors.lastname: Alharbi
authors.affiliation: Department of Pharmacology, Yong Loo Lin School of Medicine, NUS, Singapore.
authors.forename: Kodappully Sivaraman
authors.initials: KS
authors.lastname: Siveen
authors.affiliation: Cancer Science Institute of Singapore, Singapore.
authors.forename: Sakshi
authors.initials: S
authors.lastname: Sikka
authors.affiliation: Department of Pharmacology, Yong Loo Lin School of Medicine, NUS, Singapore; Cancer Science Institute of Singapore, Singapore; National University Cancer Institute, Singapore; School of Biomedical Sciences, Faculty of Health Sciences, Curtin University, Australia; Department of Biological Sciences, University of North Texas, Denton, TX, USA.
authors.forename: Alan Prem
authors.initials: AP
authors.lastname: Kumar
authors.affiliation: Department of Botany and Microbiology, College of Science, King Saud University, Riyadh 11451, Saudi Arabia; Department of Pharmacology, Yong Loo Lin School of Medicine, NUS, Singapore.
authors.forename: Gautam
authors.initials: G
authors.lastname: Sethi
authors.affiliation: Department of Physiology, Centre for Life Sciences, NUHS, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117456.
authors.forename: Lina Hsiu Kim
authors.initials: LH
authors.lastname: Lim
mesh_terms: D000818:Animals; D023181:Antimicrobial Cationic Peptides / Q000737:chemistry / Q000494:pharmacology; D001419:Bacteria / Q000254:growth & development*; D001798:Blood Proteins / Q000737:chemistry / Q000494:pharmacology; D017821:Boidae; D006801:Humans; D051379:Mice; D064801:Phospholipase A2 Inhibitors / Q000737:chemistry / Q000494:pharmacology; D054467:Phospholipases A2 / Q000737:chemistry*
chemical_list: D023181:Antimicrobial Cationic Peptides; D001798:Blood Proteins; D064801:Phospholipase A2 Inhibitors; D054467:Phospholipases A2
keywords: Antibacterial; Bacteria; Multi-drug resistance; Phospholipase A(2) inhibitory peptide (PLI); Python serum