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Abstract
AbstractThe complex composition of bacterial membranes has a significant impact on the understanding of pathogen function and their development towards antibiotic resistance. In addition to the inherent complexity and biosafety risks of studying biological pathogen membranes, the continual rise of antibiotic resistance and its significant economical and clinical consequences has motivated the development of numerous in vitro model membrane systems with tuneable compositions, geometries, and sizes. Approaches discussed in this review include liposomes, solid-supported bilayers, and computational simulations which have been used to explore various processes including drug-membrane interactions, lipid-protein interactions, host–pathogen interactions, and structure-induced bacterial pathogenesis. The advantages, limitations, and applicable analytical tools of all architectures are summarised with a perspective for future research efforts in architectural improvement and elucidation of resistance development strategies and membrane-targeting antibiotic mechanisms.
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Kumar K, Sebastiao M, Arnold AA, Bourgault S, Warschawski DE, Marcotte I. IN SITU SOLID-STATE NMR STUDY OF ANTIMICROBIAL PEPTIDE INTERACTIONs WITH ERYTHROCYTE MEMBRANES. Biophys J 2022; 121:1512-1524. [PMID: 35278426 PMCID: PMC9072582 DOI: 10.1016/j.bpj.2022.03.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 02/01/2022] [Accepted: 03/07/2022] [Indexed: 11/02/2022] Open
Abstract
Antimicrobial peptides are promising therapeutic agents to mitigate the global rise of antibiotic resistance. They generally act by perturbing the bacterial cell membrane and are thus less likely to induce resistance. Because they are membrane-active molecules, it is critical to verify and understand their potential action toward eukaryotic cells to help design effective and safe drugs. In this work, we studied the interaction of two antimicrobial peptides, aurein 1.2 and caerin 1.1, with red blood cell (RBC) membranes using in situ 31P and 2H solid-state NMR (SS-NMR). We established a protocol to integrate up to 25% of deuterated fatty acids in the membranes of ghosts, which are obtained when hemoglobin is removed from RBCs. Fatty acid incorporation and the integrity of the lipid bilayer were confirmed by SS-NMR and fluorescence confocal microscopy. Leakage assays were performed to assess the lytic power of the antimicrobial peptides. The in situ perturbation of the ghost membranes by aurein 1.2 and caerin 1.1 revealed by 31P and 2H SS-NMR is consistent with membrane perturbation through a carpet mechanism for aurein 1.2, whereas caerin 1.1 acts on RBCs via pore formation. These results are compatible with fluorescence microscopy images of the ghosts. The peptides interact with eukaryotic membranes following similar mechanisms that take place in bacteria, highlighting the importance of hydrophobicity when determining such interactions. Our work bridges model membranes and in vitro studies and provides an analytical toolbox to assess drug toxicity toward eukaryotic cells.
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Chen S, Zhang P, Xiao L, Liu Y, Wu K, Ni G, Li H, Wang T, Wu X, Chen G, Liu X. Caerin 1.1 and 1.9 Peptides from Australian Tree Frog Inhibit Antibiotic-Resistant Bacteria Growth in a Murine Skin Infection Model. Microbiol Spectr 2021; 9:e0005121. [PMID: 34259550 PMCID: PMC8552723 DOI: 10.1128/spectrum.00051-21] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Accepted: 06/18/2021] [Indexed: 01/04/2023] Open
Abstract
The host defense peptide caerin 1.9 was originally isolated from skin secretions of an Australian tree frog and inhibits the growth of a wide range of bacteria in vitro. In this study, we demonstrated that caerin 1.9 shows high bioactivity against several bacteria strains, such as Staphylococcus aureus, Acinetobacter baumannii, methicillin-resistant Staphylococcus aureus (MRSA), and Streptococcus haemolyticus in vitro. Importantly, unlike the antibiotic Tazocin, caerin 1.9 does not induce bacterial resistance after 30 rounds of in vitro culture. Moreover, caerin 1.1, another peptide of the caerin family, has an additive antibacterial effect when used together with caerin 1.9. Furthermore, caerin 1.1 and 1.9 prepared in the form of a temperature-sensitive gel inhibit MRSA growth in a skin bacterial infection model of two murine strains. These results indicate that caerin 1.1 and 1.9 peptides could be considered an alternative for conventional antibiotics. IMPORTANCE Antibiotic-resistant bacteria cause severe problems in the clinic. We show in our paper that two short peptides isolated from an Australian frog and prepared in the form of a gel are able to inhibit the growth of antibiotic-resistant bacteria in mice, and, unlike antibiotics, these peptides do not lead to the development of peptide-resistant bacteria strains.
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Affiliation(s)
- Shu Chen
- Cancer Research Institute, Foshan First People’s Hospital, Foshan, Guangdong, China
| | - Pingping Zhang
- Cancer Research Institute, Foshan First People’s Hospital, Foshan, Guangdong, China
| | - Liyin Xiao
- Cancer Research Institute, Foshan First People’s Hospital, Foshan, Guangdong, China
| | - Ying Liu
- Cancer Research Institute, Foshan First People’s Hospital, Foshan, Guangdong, China
| | - Kuihai Wu
- Clinical Microbiological Laboratory, Foshan First People’s Hospital, Foshan, Guangdong, China
| | - Guoying Ni
- Genecology Research Centre, University of the Sunshine Coast, Maroochydore, QLD, Australia
- Department of Rheumatology, Foshan Frist People’s Hospital, Foshan, Guangdong, China
| | - Hejie Li
- Genecology Research Centre, University of the Sunshine Coast, Maroochydore, QLD, Australia
| | - Tianfang Wang
- Genecology Research Centre, University of the Sunshine Coast, Maroochydore, QLD, Australia
| | - Xiaolian Wu
- Cancer Research Institute, Foshan First People’s Hospital, Foshan, Guangdong, China
| | - Guoqiang Chen
- Department of Rheumatology, Foshan Frist People’s Hospital, Foshan, Guangdong, China
| | - Xiaosong Liu
- Cancer Research Institute, Foshan First People’s Hospital, Foshan, Guangdong, China
- Genecology Research Centre, University of the Sunshine Coast, Maroochydore, QLD, Australia
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Piroozmand F, Mohammadipanah F, Faridbod F. Emerging biosensors in detection of natural products. Synth Syst Biotechnol 2020; 5:293-303. [PMID: 32954023 PMCID: PMC7484522 DOI: 10.1016/j.synbio.2020.08.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2020] [Revised: 08/23/2020] [Accepted: 08/25/2020] [Indexed: 01/10/2023] Open
Abstract
Natural products (NPs) are a valuable source in the food, pharmaceutical, agricultural, environmental, and many other industrial sectors. Their beneficial properties along with their potential toxicities make the detection, determination or quantification of NPs essential for their application. The advanced instrumental methods require time-consuming sample preparation and analysis. In contrast, biosensors allow rapid detection of NPs, especially in complex media, and are the preferred choice of detection when speed and high throughput are intended. Here, we review diverse biosensors reported for the detection of NPs. The emerging approaches for improving the efficiency of biosensors, such as microfluidics, nanotechnology, and magnetic beads, are also discussed. The simultaneous use of two detection techniques is suggested as a robust strategy for precise detection of a specific NP with structural complexity in complicated matrices. The parallel detection of a variety of NPs structures or biological activities in a mixture of extract in a single detection phase is among the anticipated future advancements in this field which can be achieved using multisystem biosensors applying multiple flow cells, sensing elements, and detection mechanisms on miniaturized folded chips.
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Affiliation(s)
- Firoozeh Piroozmand
- Pharmaceutical Biotechnology Lab, Department of Microbial Biotechnology, School of Biology and Center of Excellence in Phylogeny of Living Organisms, College of Science, University of Tehran, 14155-6455, Tehran, Iran
| | - Fatemeh Mohammadipanah
- Pharmaceutical Biotechnology Lab, Department of Microbial Biotechnology, School of Biology and Center of Excellence in Phylogeny of Living Organisms, College of Science, University of Tehran, 14155-6455, Tehran, Iran
| | - Farnoush Faridbod
- Center of Excellence in Electrochemistry, School of Chemistry, College of Science, University of Tehran, Tehran, Iran
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5
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Houri AJ, Mechler A. Mechanism of Action of the Antimicrobial Peptide Caerin1.1. ChemistrySelect 2020. [DOI: 10.1002/slct.202000851] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Aamd J. Houri
- La Trobe Institute for Molecular Science La Trobe University Melbourne VIC 3086 Australia
| | - Adam Mechler
- La Trobe Institute for Molecular Science La Trobe University Melbourne VIC 3086 Australia
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Rodrigues de Almeida N, Catazaro J, Krishnaiah M, Singh Chhonker Y, Murry DJ, Powers R, Conda-Sheridan M. Understanding interactions of Citropin 1.1 analogues with model membranes and their influence on biological activity. Peptides 2019; 119:170119. [PMID: 31336137 PMCID: PMC7161086 DOI: 10.1016/j.peptides.2019.170119] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Revised: 07/09/2019] [Accepted: 07/13/2019] [Indexed: 01/03/2023]
Abstract
The rapid emergence of resistant bacterial strains has made the search for new antibacterial agents an endeavor of paramount importance. Cationic antimicrobial peptides (AMPs) have the ability to kill resistant pathogens while diminishing the development of resistance. Citropin 1.1 (Cit 1.1) is an AMP effective against a broad range of pathogens. 20 analogues of Cit 1.1 were prepared to understand how sequence variations lead to changes in structure and biological activity. Various analogues exhibited an increased antimicrobial activity relative to Cit 1.1. The two most promising, AMP-016 (W3F) and AMP-017 (W3F, D4R, K7R) presented a 2- to 8-fold increase in activity against MRSA (both = 4 μg/mL). AMP-017 was active against E. coli (4 μg/mL), K. pneumoniae (8 μg/mL), and A. baumannii (2 μg/mL). NMR studies indicated that Cit 1.1 and its analogues form a head-to-tail helical dimer in a membrane environment, which differs from a prior study by Sikorska et al. Active peptides displayed a greater tendency to form α-helices and to dimerize when in contact with a negatively-charged membrane. Antimicrobial activity was observed to correlate to the overall stability of the α-helix and to a positively charged N-terminus. Biologically active AMPs were shown by SEM and flow cytometry to disrupt membranes in both Gram-positive and Gram-negative bacteria through a proposed carpet mechanism. Notably, active peptides exhibited typical serum stabilities and a good selectivity for bacterial cells over mammalian cells, which supports the potential use of Cit 1.1 analogues as a novel broad-spectrum antibiotic for drug-resistant bacterial infections.
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Affiliation(s)
| | - Jonathan Catazaro
- Department of Chemistry, University of Nebraska - Lincoln, NE, 68588-0304, USA
| | - Maddeboina Krishnaiah
- Department of Pediatrics Computational Chemistry, University of Nebraska Medical Center - Omaha, NE, 68198-2168, USA
| | - Yashpal Singh Chhonker
- Clinical Pharmacology Laboratory, Department of Pharmacy Practice, University of Nebraska Medical Center - Omaha, NE, 68198-6145, USA
| | - Daryl J Murry
- Clinical Pharmacology Laboratory, Department of Pharmacy Practice, University of Nebraska Medical Center - Omaha, NE, 68198-6145, USA
| | - Robert Powers
- Department of Chemistry, University of Nebraska - Lincoln, NE, 68588-0304, USA; Nebraska Center for Integrated Biomolecular Communication, Lincoln, NE, 68588-0304, USA.
| | - Martin Conda-Sheridan
- Department of Pharmaceutical Sciences, University of Nebraska Medical Center - Omaha, NE, 68198-6125, USA.
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Avci FG, Akbulut BS, Ozkirimli E. Membrane Active Peptides and Their Biophysical Characterization. Biomolecules 2018; 8:biom8030077. [PMID: 30135402 PMCID: PMC6164437 DOI: 10.3390/biom8030077] [Citation(s) in RCA: 115] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Revised: 08/08/2018] [Accepted: 08/13/2018] [Indexed: 12/12/2022] Open
Abstract
In the last 20 years, an increasing number of studies have been reported on membrane active peptides. These peptides exert their biological activity by interacting with the cell membrane, either to disrupt it and lead to cell lysis or to translocate through it to deliver cargos into the cell and reach their target. Membrane active peptides are attractive alternatives to currently used pharmaceuticals and the number of antimicrobial peptides (AMPs) and peptides designed for drug and gene delivery in the drug pipeline is increasing. Here, we focus on two most prominent classes of membrane active peptides; AMPs and cell-penetrating peptides (CPPs). Antimicrobial peptides are a group of membrane active peptides that disrupt the membrane integrity or inhibit the cellular functions of bacteria, virus, and fungi. Cell penetrating peptides are another group of membrane active peptides that mainly function as cargo-carriers even though they may also show antimicrobial activity. Biophysical techniques shed light on peptide–membrane interactions at higher resolution due to the advances in optics, image processing, and computational resources. Structural investigation of membrane active peptides in the presence of the membrane provides important clues on the effect of the membrane environment on peptide conformations. Live imaging techniques allow examination of peptide action at a single cell or single molecule level. In addition to these experimental biophysical techniques, molecular dynamics simulations provide clues on the peptide–lipid interactions and dynamics of the cell entry process at atomic detail. In this review, we summarize the recent advances in experimental and computational investigation of membrane active peptides with particular emphasis on two amphipathic membrane active peptides, the AMP melittin and the CPP pVEC.
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Affiliation(s)
- Fatma Gizem Avci
- Bioengineering Department, Marmara University, Kadikoy, 34722 Istanbul, Turkey.
| | | | - Elif Ozkirimli
- Chemical Engineering Department, Bogazici University, Bebek, 34342 Istanbul, Turkey.
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Liquid crystalline bacterial outer membranes are critical for antibiotic susceptibility. Proc Natl Acad Sci U S A 2018; 115:E7587-E7594. [PMID: 30037998 DOI: 10.1073/pnas.1803975115] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The outer membrane (OM) of Gram-negative bacteria is a robust, impermeable, asymmetric bilayer of outer lipopolysaccharides (LPSs) and inner phospholipids containing selective pore proteins which confer on it the properties of a molecular sieve. This structure severely limits the variety of antibiotic molecules effective against Gram-negative pathogens and, as antibiotic resistance has increased, so has the need to solve the OM permeability problem. Polymyxin B (PmB) represents those rare antibiotics which act directly on the OM and which offer a distinct starting point for new antibiotic development. Here we investigate PmB's interactions with in vitro OM models and show how the physical state of the lipid matrix of the OM is a critical factor in regulating the interaction with the antimicrobial peptide. Using neutron reflectometry and infrared spectroscopy, we reveal the structural and chemical changes induced by PmB on OM models of increasing complexity. In particular, only a tightly packed model reproduced the temperature-controlled disruption of the asymmetric lipid bilayer by PmB observed in vivo. By measuring the order of outer-leaflet LPS and inner-leaflet phospholipids, we show that PmB insertion is dependent on the phase transition of LPS from the gel to the liquid crystalline state. The demonstration of a lipid phase transition in the physiological temperature range also supports the hypothesis that bacteria grown at different temperatures adapt their LPS structures to maintain a homeoviscous OM.
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Lee TH, Hirst DJ, Kulkarni K, Del Borgo MP, Aguilar MI. Exploring Molecular-Biomembrane Interactions with Surface Plasmon Resonance and Dual Polarization Interferometry Technology: Expanding the Spotlight onto Biomembrane Structure. Chem Rev 2018; 118:5392-5487. [PMID: 29793341 DOI: 10.1021/acs.chemrev.7b00729] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The molecular analysis of biomolecular-membrane interactions is central to understanding most cellular systems but has emerged as a complex technical challenge given the complexities of membrane structure and composition across all living cells. We present a review of the application of surface plasmon resonance and dual polarization interferometry-based biosensors to the study of biomembrane-based systems using both planar mono- or bilayers or liposomes. We first describe the optical principals and instrumentation of surface plasmon resonance, including both linear and extraordinary transmission modes and dual polarization interferometry. We then describe the wide range of model membrane systems that have been developed for deposition on the chips surfaces that include planar, polymer cushioned, tethered bilayers, and liposomes. This is followed by a description of the different chemical immobilization or physisorption techniques. The application of this broad range of engineered membrane surfaces to biomolecular-membrane interactions is then overviewed and how the information obtained using these techniques enhance our molecular understanding of membrane-mediated peptide and protein function. We first discuss experiments where SPR alone has been used to characterize membrane binding and describe how these studies yielded novel insight into the molecular events associated with membrane interactions and how they provided a significant impetus to more recent studies that focus on coincident membrane structure changes during binding of peptides and proteins. We then discuss the emerging limitations of not monitoring the effects on membrane structure and how SPR data can be combined with DPI to provide significant new information on how a membrane responds to the binding of peptides and proteins.
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Affiliation(s)
- Tzong-Hsien Lee
- Department of Biochemistry and Molecular Biology and Biomedicine Discovery Institute , Monash University , Clayton , VIC 3800 , Australia
| | - Daniel J Hirst
- Department of Biochemistry and Molecular Biology and Biomedicine Discovery Institute , Monash University , Clayton , VIC 3800 , Australia
| | - Ketav Kulkarni
- Department of Biochemistry and Molecular Biology and Biomedicine Discovery Institute , Monash University , Clayton , VIC 3800 , Australia
| | - Mark P Del Borgo
- Department of Biochemistry and Molecular Biology and Biomedicine Discovery Institute , Monash University , Clayton , VIC 3800 , Australia
| | - Marie-Isabel Aguilar
- Department of Biochemistry and Molecular Biology and Biomedicine Discovery Institute , Monash University , Clayton , VIC 3800 , Australia
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10
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Patel S, Akhtar N. Antimicrobial peptides (AMPs): The quintessential 'offense and defense' molecules are more than antimicrobials. Biomed Pharmacother 2017; 95:1276-1283. [PMID: 28938518 DOI: 10.1016/j.biopha.2017.09.042] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Revised: 09/08/2017] [Accepted: 09/10/2017] [Indexed: 12/17/2022] Open
Abstract
Antimicrobial peptides (AMPs) are cationic amphiphilic molecules with α-helix or β-sheet linear motifs and linear or cyclic configurations. For their role in 'defense and offense', they are present in all living organisms. AMPs are named so, as they inhibit a wide array of microbes by membrane pore formation and subsequent perturbation of mitochondrial membrane ionic balance. However, their functional repertoire is expanding with validated roles in cytotoxicity, wound healing, angiogenesis, apoptosis, and chemotaxis [1]. A number of endogenous AMPs have been characterized in human body such as defensins, cathelicidins, histatins etc. They mediate critical functions, but when homeostasis is broken, they turn hostile and initiate inflammatory diseases. This review discusses the sources of therapeutic AMPs; auto-immunity risks of endogenous AMPs, and their dermatological applications; normally overlooked risks of the peptides; and scopes ahead. This holistic work is expected to be a valuable reference for further research in this field.
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Affiliation(s)
- Seema Patel
- Bioinformatics and Medical Informatics Research Center, San Diego State University, San Diego 92182, USA.
| | - Nadeem Akhtar
- Department of Animal Biosciences, University of Guelph, Guelph, Ontario N1G 2W1, Canada
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11
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Rochín-Medina JJ, Ramírez-Medina HK, Rangel-Peraza JG, Pineda-Hidalgo KV, Iribe-Arellano P. Use of whey as a culture medium for Bacillus clausii for the production of protein hydrolysates with antimicrobial and antioxidant activity. FOOD SCI TECHNOL INT 2017; 24:35-42. [PMID: 28816527 DOI: 10.1177/1082013217724705] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The use of whey as a natural culture medium to produce hydrolysates with antimicrobial from Bacillus clausii is the objective of this research. The fermentation process was carried out at 25 ℃ for five days, where proteolytic activity, soluble peptides quantification, and antimicrobial activity using the disc diffusion method were determined every day. The fermented whey reached values of proteolytic activity between 90 and 260 U ml-1 and a production of soluble peptides between 100 and 2070 µg ml-1. The maximum values were reached after three days of fermentation to all determinations. In addition, the inhibition zone of fermented whey against Salmonella Typhimurium, Escherichia coli, Shigella flexneri, Staphylococcus aureus, Listeria monocytogenes, and Enterococcus faecalis strains were 13.7, 13.2, 14.4, 14.6, 9.8, 15.7 mm, respectively. The hydrolysates inhibited the 2, 2'-azinobis (3-ethylbenzothiazoline- 6-sulfonic acid) (ABTS) and 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radicals by 85 and 80%, respectively. The whey was used to allow the growth of B. clausii and to generate peptides with antioxidant and antimicrobial activity through the hydrolysis of proteins present in the natural culture medium. This process could be used for the development of new dairy products added with probiotics.
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Affiliation(s)
- Jesús J Rochín-Medina
- 1 Departamento de Ingeniería Bioquímica, 149209 Instituto Tecnológico de Culiacán , Culiacán, México.,2 División de Estudios de Posgrado e Investigación, 149209 Instituto Tecnológico de Culiacán , Culiacán, México
| | - Hilda K Ramírez-Medina
- 1 Departamento de Ingeniería Bioquímica, 149209 Instituto Tecnológico de Culiacán , Culiacán, México.,2 División de Estudios de Posgrado e Investigación, 149209 Instituto Tecnológico de Culiacán , Culiacán, México
| | - Jesús G Rangel-Peraza
- 2 División de Estudios de Posgrado e Investigación, 149209 Instituto Tecnológico de Culiacán , Culiacán, México
| | - Karen V Pineda-Hidalgo
- 3 Programa Regional de Posgrado en Biotecnología, Facultad de Ciencias Químico-Biológicas, 27774 Universidad Autónoma de Sinaloa , Culiacán, México
| | - Pablo Iribe-Arellano
- 1 Departamento de Ingeniería Bioquímica, 149209 Instituto Tecnológico de Culiacán , Culiacán, México
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Laadhari M, Arnold AA, Gravel AE, Separovic F, Marcotte I. Interaction of the antimicrobial peptides caerin 1.1 and aurein 1.2 with intact bacteria by 2 H solid-state NMR. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2016; 1858:2959-2964. [DOI: 10.1016/j.bbamem.2016.09.009] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Revised: 08/11/2016] [Accepted: 09/12/2016] [Indexed: 11/17/2022]
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13
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Mularski A, Wilksch JJ, Hanssen E, Strugnell RA, Separovic F. Atomic force microscopy of bacteria reveals the mechanobiology of pore forming peptide action. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2016; 1858:1091-8. [DOI: 10.1016/j.bbamem.2016.03.002] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2015] [Revised: 02/23/2016] [Accepted: 03/01/2016] [Indexed: 11/26/2022]
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O’Brien-Simpson NM, Pantarat N, Attard TJ, Walsh KA, Reynolds EC. A Rapid and Quantitative Flow Cytometry Method for the Analysis of Membrane Disruptive Antimicrobial Activity. PLoS One 2016; 11:e0151694. [PMID: 26986223 PMCID: PMC4795541 DOI: 10.1371/journal.pone.0151694] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2015] [Accepted: 03/02/2016] [Indexed: 11/19/2022] Open
Abstract
We describe a microbial flow cytometry method that quantifies within 3 hours antimicrobial peptide (AMP) activity, termed Minimum Membrane Disruptive Concentration (MDC). Increasing peptide concentration positively correlates with the extent of bacterial membrane disruption and the calculated MDC is equivalent to its MBC. The activity of AMPs representing three different membranolytic modes of action could be determined for a range of Gram positive and negative bacteria, including the ESKAPE pathogens, E. coli and MRSA. By using the MDC50 concentration of the parent AMP, the method provides high-throughput, quantitative screening of AMP analogues. A unique feature of the MDC assay is that it directly measures peptide/bacteria interactions and lysed cell numbers rather than bacteria survival as with MIC and MBC assays. With the threat of multi-drug resistant bacteria, this high-throughput MDC assay has the potential to aid in the development of novel antimicrobials that target bacteria with improved efficacy.
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Affiliation(s)
- Neil M. O’Brien-Simpson
- Oral Health Cooperative Research Centre, Melbourne Dental School, Bio21 Institute, The University of Melbourne, Melbourne, Australia
| | - Namfon Pantarat
- Oral Health Cooperative Research Centre, Melbourne Dental School, Bio21 Institute, The University of Melbourne, Melbourne, Australia
| | - Troy J. Attard
- Oral Health Cooperative Research Centre, Melbourne Dental School, Bio21 Institute, The University of Melbourne, Melbourne, Australia
| | - Katrina A. Walsh
- Oral Health Cooperative Research Centre, Melbourne Dental School, Bio21 Institute, The University of Melbourne, Melbourne, Australia
| | - Eric C. Reynolds
- Oral Health Cooperative Research Centre, Melbourne Dental School, Bio21 Institute, The University of Melbourne, Melbourne, Australia
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15
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Carbohydrate scaffolds as glycosyltransferase inhibitors with in vivo antibacterial activity. Nat Commun 2015; 6:7719. [PMID: 26194781 PMCID: PMC4530474 DOI: 10.1038/ncomms8719] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Accepted: 06/05/2015] [Indexed: 02/08/2023] Open
Abstract
The rapid rise of multi-drug-resistant bacteria is a global healthcare crisis, and new antibiotics are urgently required, especially those with modes of action that have low-resistance potential. One promising lead is the liposaccharide antibiotic moenomycin that inhibits bacterial glycosyltransferases, which are essential for peptidoglycan polymerization, while displaying a low rate of resistance. Unfortunately, the lipophilicity of moenomycin leads to unfavourable pharmacokinetic properties that render it unsuitable for systemic administration. In this study, we show that using moenomycin and other glycosyltransferase inhibitors as templates, we were able to synthesize compound libraries based on novel pyranose scaffold chemistry, with moenomycin-like activity, but with improved drug-like properties. The novel compounds exhibit in vitro inhibition comparable to moenomycin, with low toxicity and good efficacy in several in vivo models of infection. This approach based on non-planar carbohydrate scaffolds provides a new opportunity to develop new antibiotics with low propensity for resistance induction.
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16
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Sani MA, Henriques ST, Weber D, Separovic F. Bacteria May Cope Differently from Similar Membrane Damage Caused by the Australian Tree Frog Antimicrobial Peptide Maculatin 1.1. J Biol Chem 2015; 290:19853-62. [PMID: 26100634 DOI: 10.1074/jbc.m115.643262] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Indexed: 11/06/2022] Open
Abstract
Maculatin 1.1 (Mac1) is an antimicrobial peptide from the skin of Australian tree frogs and is known to possess selectivity toward Gram-positive bacteria. Although Mac1 has membrane disrupting activity, it is not known how Mac1 selectively targets Gram-positive over Gram-negative bacteria. The interaction of Mac1 with Escherichia coli, Staphylococcus aureus, and human red blood cells (hRBC) and with their mimetic model membranes is here reported. The peptide showed a 16-fold greater growth inhibition activity against S. aureus (4 μM) than against E. coli (64 μM) and an intermediate cytotoxicity against hRBC (30 μM). Surprisingly, Sytox Green uptake monitored by flow cytometry showed that Mac1 compromised both bacterial membranes with similar efficiency at ∼20-fold lower concentration than the reported minimum inhibition concentration against S. aureus. Mac1 also reduced the negative potential of S. aureus and E. coli membrane with similar efficacy. Furthermore, liposomes mimicking the cell membrane of S. aureus (POPG/TOCL) and E. coli (POPE/POPG) were lysed at similar concentrations, whereas hRBC-like vesicles (POPC/SM/Chol) remained mostly intact in the presence of Mac1. Remarkably, when POPG/TOCL and POPE/POPG liposomes were co-incubated, Mac1 did not induce leakage from POPE/POPG liposomes, suggesting a preference toward POPG/TOCL membranes that was supported by surface plasma resonance assays. Interestingly, circular dichroism spectroscopy showed a similar helical conformation in the presence of the anionic liposomes but not the hRBC mimics. Overall, the study showed that Mac1 disrupts bacterial membranes in a similar fashion before cell death events and would preferentially target S. aureus over E. coli or hRBC membranes.
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Affiliation(s)
- Marc-Antoine Sani
- From the School of Chemistry, Bio21 Institute, The University of Melbourne, Parkville, Victoria 3010, Australia and
| | - Sónia Troeira Henriques
- the Institute for Molecular Bioscience, University of Queensland, St. Lucia, Queensland 4072, Australia
| | - Daniel Weber
- From the School of Chemistry, Bio21 Institute, The University of Melbourne, Parkville, Victoria 3010, Australia and
| | - Frances Separovic
- From the School of Chemistry, Bio21 Institute, The University of Melbourne, Parkville, Victoria 3010, Australia and
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Affinities and in-plane stress forces between glycopeptide antibiotics and biomimetic bacterial membranes. SENSING AND BIO-SENSING RESEARCH 2015. [DOI: 10.1016/j.sbsr.2014.10.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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18
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Cheng M, Huang JX, Ramu S, Butler MS, Cooper MA. Ramoplanin at bactericidal concentrations induces bacterial membrane depolarization in Staphylococcus aureus. Antimicrob Agents Chemother 2014; 58:6819-27. [PMID: 25182650 PMCID: PMC4249368 DOI: 10.1128/aac.00061-14] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2014] [Accepted: 08/26/2014] [Indexed: 12/22/2022] Open
Abstract
Ramoplanin is an actinomycetes-derived antibiotic with broad-spectrum activity against Gram-positive bacteria that has been evaluated in clinical trials for the treatment of gastrointestinal vancomycin-resistant enterococci (VRE) and Clostridium difficile infections. Recent studies have proposed that ramoplanin binds to bacterial membranes as a C2 symmetrical dimer that can sequester Lipid II, which causes inhibition of cell wall peptidoglycan biosynthesis and cell death. In this study, ramoplanin was shown to bind to anionic and zwitterionic membrane mimetics with a higher affinity for anionic membranes and to induce membrane depolarization of methicillin-susceptible Staphylococcus aureus (MSSA) ATCC 25923 at concentrations at or above the minimal bactericidal concentration (MBC). The ultrastructural effects of ramoplanin on S. aureus were also examined by transmission electron microscopy (TEM), and this showed dramatic changes to bacterial cell morphology. The correlation observed between membrane depolarization and bacterial cell viability suggests that this mechanism may contribute to the bactericidal activity of ramoplanin.
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Affiliation(s)
- Mu Cheng
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Johnny X Huang
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Soumya Ramu
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Mark S Butler
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Matthew A Cooper
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
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19
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Dye-release assay for investigation of antimicrobial peptide activity in a competitive lipid environment. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2014; 43:445-50. [PMID: 24906225 DOI: 10.1007/s00249-014-0970-0] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Revised: 05/13/2014] [Accepted: 05/20/2014] [Indexed: 10/25/2022]
Abstract
A dye-release method for investigating the effect of a competitive lipid environment on the activity of two membrane-disrupting antimicrobial peptides (AMP), maculatin 1.1 and aurein 1.2, is presented. The results support the general conclusion that AMP have greater affinity for negatively charged membranes, for example bacterial membranes, than for the neutral membrane surface found in eukaryotic cells, but only within a competitive lipid environment. Indeed, in a single-model membrane environment, both peptides were more potent against neutral vesicles than against charged vesicles. The approach was also used to investigate the effect of pre-incubating the peptides in a neutral lipid environment then introducing charged lipid vesicles. Maculatin was shown to migrate from the neutral lipid bilayers, where pores had already formed, to the charged membrane bilayers. This result was also observed for charged-to-charged bilayers but, interestingly, not for neutral-to-neutral lipid interfaces. Aurein was able to migrate from either lipid environment, indicating weaker binding to lipid membranes, and a different molecular mechanism for lysis of lipid bilayers. Competitive lipid environments could be used to assess other critical conditions that modulate the activity of membrane peptides or proteins.
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Maculatin 1.1 disrupts Staphylococcus aureus lipid membranes via a pore mechanism. Antimicrob Agents Chemother 2013; 57:3593-600. [PMID: 23689707 DOI: 10.1128/aac.00195-13] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Maculatin 1.1 (Mac1) showed potent activity against Staphylococcus aureus with an MIC of 7 μM. The mode of action of Mac1 was investigated by combining assays with S. aureus cells and lipid vesicles mimicking their membrane composition. A change in Mac1 conformation was monitored by circular dichroism from random coil to ca. 70% α-helix structure in contact with vesicles. Electron micrographs of S. aureus incubated with Mac1 showed rough and rippled cell surfaces. An uptake of 65% of small (FD, 4 kDa [FD-4]) and 35% of large (RD, 40 kDa [RD-40]) fluorescent dextrans by S. aureus was observed by flow cytometry and indicate that Mac1 formed a pore of finite size. In model membranes with both dyes encapsulated together, the full release of FD-4 occurred, but only 40% of RD-40 was reached, supporting the flow cytometry results, and indicating a pore size between 1.4 and 4.5 nm. Finally, solid-state nuclear magnetic resonance showed formation of an isotropic phase signifying highly mobile lipids such as encountered in a toroidal pore structure. Overall, Mac1 is a promising antimicrobial peptide with the potent capacity to form pores in S. aureus membranes.
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Tam C, Mun JJ, Evans DJ, Fleiszig SMJ. Cytokeratins mediate epithelial innate defense through their antimicrobial properties. J Clin Invest 2012; 122:3665-77. [PMID: 23006328 DOI: 10.1172/jci64416] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2012] [Accepted: 07/26/2012] [Indexed: 02/06/2023] Open
Abstract
Epithelial cells express antimicrobial proteins in response to invading pathogens, although little is known regarding epithelial defense mechanisms during healthy conditions. Here we report that epithelial cytokeratins have innate defense properties because they constitutively produce cytoprotective antimicrobial peptides. Glycine-rich C-terminal fragments derived from human cytokeratin 6A were identified in bactericidal lysate fractions of human corneal epithelial cells. Structural analysis revealed that these keratin-derived antimicrobial peptides (KDAMPs) exhibited coil structures with low α-helical content. Synthetic analogs of these KDAMPS showed rapid bactericidal activity against multiple pathogens and protected epithelial cells against bacterial virulence mechanisms, while a scrambled peptide showed no bactericidal activity. However, the bactericidal activity of a specific KDAMP was somewhat reduced by glycine-alanine substitutions. KDAMP activity involved bacterial binding and permeabilization, but the activity was unaffected by peptide charge or physiological salt concentration. Knockdown of cytokeratin 6A markedly reduced the bactericidal activity of epithelial cell lysates in vitro and increased the susceptibility of murine corneas to bacterial adherence in vivo. These data suggest that epithelial cytokeratins function as endogenous antimicrobial peptides in the host defense against infection and that keratin-derived antimicrobials may serve as effective therapeutic agents.
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Affiliation(s)
- Connie Tam
- School of Optometry, University of California, Berkeley, Berkeley, CA 94720-2020, USA
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22
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Bowie JH, Separovic F, Tyler MJ. Host-defense peptides of Australian anurans. Part 2. Structure, activity, mechanism of action, and evolutionary significance. Peptides 2012; 37:174-88. [PMID: 22771617 DOI: 10.1016/j.peptides.2012.06.017] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/28/2012] [Revised: 06/26/2012] [Accepted: 06/26/2012] [Indexed: 01/01/2023]
Abstract
A previous review summarized research prior to 2004 carried out on the bioactive host-defense peptides contained in the skin secretions of Australian anurans (frogs and toads). This review covers the extension of that research from 2004 to 2012, and includes membrane-active peptides (including antibacterial, anticancer, antifungal and antiviral peptides) together with the mechanisms by which these peptides interact with model membranes, peptides that may be classified as "neuropeptides" (including smooth muscle active peptides, opioids and immunomodulators) and peptides which inhibit the formation of nitric oxide from neuronal nitric oxide synthase. The review discusses the outcome of cDNA sequencing of signal-spacer-active peptides from an evolutionary viewpoint, and also lists those peptides for which activities have not been found to this time.
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Affiliation(s)
- John H Bowie
- Department of Chemistry, School of Chemistry and Physics, The University of Adelaide, South Australia 5005, Australia.
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