1
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Lee TH, Charchar P, Separovic F, Reid GE, Yarovsky I, Aguilar MI. The intricate link between membrane lipid structure and composition and membrane structural properties in bacterial membranes. Chem Sci 2024; 15:3408-3427. [PMID: 38455013 PMCID: PMC10915831 DOI: 10.1039/d3sc04523d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2023] [Accepted: 01/26/2024] [Indexed: 03/09/2024] Open
Abstract
It is now evident that the cell manipulates lipid composition to regulate different processes such as membrane protein insertion, assembly and function. Moreover, changes in membrane structure and properties, lipid homeostasis during growth and differentiation with associated changes in cell size and shape, and responses to external stress have been related to drug resistance across mammalian species and a range of microorganisms. While it is well known that the biomembrane is a fluid self-assembled nanostructure, the link between the lipid components and the structural properties of the lipid bilayer are not well understood. This perspective aims to address this topic with a view to a more detailed understanding of the factors that regulate bilayer structure and flexibility. We describe a selection of recent studies that address the dynamic nature of bacterial lipid diversity and membrane properties in response to stress conditions. This emerging area has important implications for a broad range of cellular processes and may open new avenues of drug design for selective cell targeting.
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Affiliation(s)
- Tzong-Hsien Lee
- Department of Biochemistry and Molecular Biology, Monash University Clayton VIC 3800 Australia
| | - Patrick Charchar
- School of Engineering, RMIT University Melbourne Victoria 3001 Australia
| | - Frances Separovic
- School of Chemistry, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne VIC 3010 Australia
| | - Gavin E Reid
- School of Chemistry, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne VIC 3010 Australia
- Department of Biochemistry and Pharmacology, University of Melbourne Parkville VIC 3010 Australia
| | - Irene Yarovsky
- School of Engineering, RMIT University Melbourne Victoria 3001 Australia
| | - Marie-Isabel Aguilar
- Department of Biochemistry and Molecular Biology, Monash University Clayton VIC 3800 Australia
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2
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Teuber A, Caniglia G, Barth H, Kranz C, Mizaikoff B. Thin-Film Waveguide Laser Spectroscopy: A Novel Platform for Bacterial Analysis. Anal Chem 2023; 95:16600-16608. [PMID: 37883708 DOI: 10.1021/acs.analchem.3c02782] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2023]
Abstract
Bacterial sensing based on quantum cascade laser spectroscopy coupled with diamond or gallium arsenide thin-film waveguides is a novel analytical tool for gaining high-resolution infrared spectroscopic information of planktonic and sessile bacteria, as shown in the present study for Escherichia coli. During observation periods of up to 24 h, diamond and gallium arsenide thin-film waveguide laser spectroscopy was compared to information obtained via conventional Fourier transform infrared spectroscopy. The proliferation behavior of E. coli at those surfaces was complementarily investigated using atomic force microscopy and scanning electron microscopy.
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Affiliation(s)
- Andrea Teuber
- Institute of Analytical and Bioanalytical Chemistry, University of Ulm, 89081 Ulm, Germany
| | - Giada Caniglia
- Institute of Analytical and Bioanalytical Chemistry, University of Ulm, 89081 Ulm, Germany
| | - Holger Barth
- Institute of Experimental and Clinical Pharmacology and Toxicology and Pharmacology of Natural Products, University of Ulm, 89081 Ulm, Germany
| | - Christine Kranz
- Institute of Analytical and Bioanalytical Chemistry, University of Ulm, 89081 Ulm, Germany
| | - Boris Mizaikoff
- Institute of Analytical and Bioanalytical Chemistry, University of Ulm, 89081 Ulm, Germany
- Hahn-Schickard, 89077 Ulm, Germany
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3
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Chen EHL, Wang CH, Liao YT, Chan FY, Kanaoka Y, Uchihashi T, Kato K, Lai L, Chang YW, Ho MC, Chen RPY. Visualizing the membrane disruption action of antimicrobial peptides by cryo-electron tomography. Nat Commun 2023; 14:5464. [PMID: 37673860 PMCID: PMC10482868 DOI: 10.1038/s41467-023-41156-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Accepted: 08/24/2023] [Indexed: 09/08/2023] Open
Abstract
The abuse of antibiotics has led to the emergence of multidrug-resistant microbial pathogens, presenting a pressing challenge in global healthcare. Membrane-disrupting antimicrobial peptides (AMPs) combat so-called superbugs via mechanisms different than conventional antibiotics and have good application prospects in medicine, agriculture, and the food industry. However, the mechanism-of-action of AMPs has not been fully characterized at the cellular level due to a lack of high-resolution imaging technologies that can capture cellular-membrane disruption events in the hydrated state. Previously, we reported PepD2M, a de novo-designed AMP with potent and wide-spectrum bactericidal and fungicidal activity. In this study, we use cryo-electron tomography (cryo-ET) and high-speed atomic force microscopy (HS-AFM) to directly visualize the pepD2M-induced disruption of the outer and inner membranes of the Gram-negative bacterium Escherichia coli, and compared with a well-known pore-forming peptide, melittin. Our high-resolution cryo-ET images reveal how pepD2M disrupts the E. coli membrane using a carpet/detergent-like mechanism. Our studies reveal the direct membrane-disrupting consequence of AMPs on the bacterial membrane by cryo-ET, and this information provides critical insights into the mechanisms of this class of antimicrobial agents.
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Affiliation(s)
- Eric H-L Chen
- Institute of Biological Chemistry, Academia Sinica, Taipei, 11529, Taiwan
| | - Chun-Hsiung Wang
- Institute of Biological Chemistry, Academia Sinica, Taipei, 11529, Taiwan
| | - Yi-Ting Liao
- Institute of Biological Chemistry, Academia Sinica, Taipei, 11529, Taiwan
| | - Feng-Yueh Chan
- Department of Physics, Nagoya University, Nagoya, 464-8602, Japan
| | - Yui Kanaoka
- Department of Physics, Nagoya University, Nagoya, 464-8602, Japan
| | - Takayuki Uchihashi
- Department of Physics, Nagoya University, Nagoya, 464-8602, Japan
- Institute for Glyco-core Research (iGCORE), Nagoya University, Nagoya, 464-8602, Japan
- Exploratory Research Center on Life and Living Systems (ExCELLS), National Institutes of Natural Sciences, Okazaki, Aichi, 444-8787, Japan
| | - Koichi Kato
- Exploratory Research Center on Life and Living Systems (ExCELLS), National Institutes of Natural Sciences, Okazaki, Aichi, 444-8787, Japan
- Institute for Molecular Science, National Institutes of Natural Sciences, Okazaki, Aichi, 444-8787, Japan
- Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, 467-8603, Japan
| | - Longsheng Lai
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104-6059, USA
| | - Yi-Wei Chang
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104-6059, USA
| | - Meng-Chiao Ho
- Institute of Biological Chemistry, Academia Sinica, Taipei, 11529, Taiwan.
- Institute of Biochemical Sciences, National Taiwan University, Taipei, 10617, Taiwan.
- Institute of Biochemistry and Molecular Biology, College of Medicine, National Taiwan University, Taipei, 100, Taiwan.
| | - Rita P-Y Chen
- Institute of Biological Chemistry, Academia Sinica, Taipei, 11529, Taiwan.
- Institute of Biochemical Sciences, National Taiwan University, Taipei, 10617, Taiwan.
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4
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Laroque S, Garcia Maset R, Hapeshi A, Burgevin F, Locock KES, Perrier S. Synthetic Star Nanoengineered Antimicrobial Polymers as Antibiofilm Agents: Bacterial Membrane Disruption and Cell Aggregation. Biomacromolecules 2023. [PMID: 37300501 DOI: 10.1021/acs.biomac.3c00150] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Antimicrobial resistance has become a worldwide issue, with multiresistant bacterial strains emerging at an alarming rate. Multivalent antimicrobial polymer architectures such as bottle brush or star polymers have shown great potential, as they could lead to enhanced binding and interaction with the bacterial cell membrane. In this study, a library of amphiphilic star copolymers and their linear copolymer equivalents, based on acrylamide monomers, were synthesized via RAFT polymerization. Their monomer distribution and molecular weight were varied. Subsequently, their antimicrobial activity toward a Gram-negative bacterium (Pseudomonas aeruginosa PA14) and a Gram-positive bacterium (Staphylococcus aureus USA300) and their hemocompatibility were investigated. The statistical star copolymer, S-SP25, showed an improved antimicrobial activity compared to its linear equivalent againstP. aeruginosaPA14. The star architecture enhanced its antimicrobial activity, causing bacterial cell aggregation, as revealed via electron microscopy. However, it also induced increased red blood cell aggregation compared to its linear equivalents. Changing/shifting the position of the cationic block to the core of the structure prevents the cell aggregation effect while maintaining a potent antimicrobial activity for the smallest star copolymer. Finally, this compound showed antibiofilm properties against a robust in vitro biofilm model.
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Affiliation(s)
- Sophie Laroque
- Department of Chemistry, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, U.K
| | - Ramón Garcia Maset
- Department of Chemistry, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, U.K
- Warwick Medical School, University of Warwick, Coventry CV4 7AL, U.K
| | - Alexia Hapeshi
- Department of Chemistry, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, U.K
| | - Fannie Burgevin
- Department of Chemistry, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, U.K
| | | | - Sébastien Perrier
- Department of Chemistry, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, U.K
- Warwick Medical School, University of Warwick, Coventry CV4 7AL, U.K
- Faculty of Pharmacy and Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, Victoria 3052, Australia
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5
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Elsbroek L, Amiteye D, Schreiber S, Herrmann F. Molecular Imaging of Isolated Escherichia coli DH5α Peptidoglycan Sacculi Identifies the Mechanism of Action of Cell Wall-Inhibiting Antibiotics. ACS Chem Biol 2023; 18:848-860. [PMID: 36893440 DOI: 10.1021/acschembio.2c00945] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/11/2023]
Abstract
Antibiotic resistance of pathogenic bacteria needs to be urgently addressed by the development of new antibacterial entities. Although the prokaryotic cell wall comprises a valuable target for this purpose, development of novel cell wall-active antibiotics is mostly missing today. This is mainly caused by hindrances in the assessment of isolated enzymes of the co-dependent murein synthesis machineries, e.g., the elongasome and divisome. We therefore present imaging methodologies to evaluate inhibitors of bacterial cell wall synthesis by high-resolution atomic force microscopy on isolated Escherichia coli murein sacculi. With the ability to elucidate the peptidoglycan ultrastructure of E. coli cells, unprecedented molecular insights into the mechanisms of antibiotics were established. The nanoscopic impairments introduced by ampicillin, amoxicillin, and fosfomycin were not only identified by AFM but readily correlated with their known mechanism of action. These valuable in vitro capabilities will facilitate the identification and evaluation of new antibiotic leads in the future.
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Affiliation(s)
- Leonardo Elsbroek
- Institute of Pharmaceutical Biology and Phytochemistry, University of Münster, D-48149 Münster, Germany
| | - Daniel Amiteye
- Institute of Pharmaceutical Biology and Phytochemistry, University of Münster, D-48149 Münster, Germany
| | - Sebastian Schreiber
- Institute of Pharmaceutical and Medicinal Chemistry, University of Münster, D-48149 Münster, Germany
| | - Fabian Herrmann
- Institute of Pharmaceutical Biology and Phytochemistry, University of Münster, D-48149 Münster, Germany
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6
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Nanajkar N, Mruthyunjaya LS, Nagarajan D. A Simple Radioassay to Detect Nanoscale Membrane Disruption. Methods Protoc 2023; 6:mps6020023. [PMID: 36961043 PMCID: PMC10037656 DOI: 10.3390/mps6020023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Revised: 02/18/2023] [Accepted: 02/21/2023] [Indexed: 03/02/2023] Open
Abstract
Understanding the mechanisms and kinetics of membrane damage is of interest to researchers in several overlapping fields of biology. In this study, we describe the development and validation of a simple 32PO43- release radioassay used to track nanometer-scale damage to the bacterial cell membrane. Nanoscale membrane damage will result in the release of small cytoplasmic molecules, such as amino acids, sugars, and osmolytes. Our radioassay tracks the release of these molecules using the release of cytoplasmic 32PO43- as a proxy. Our assay can both detect 32PO43- release and track release kinetics in the order of minutes. We demonstrate the use of our radioassay using A. baumannii treated with colistin and Ω76: two agents known to cause membrane damage. Our assay tracks greater membrane damage in A. baumannii treated with both these agents, compared to an untreated control. Our assay fills a niche that is not covered by traditional 51Cr release radioassays and fluorescent staining techniques. Furthermore, our assay can potentially be used to track membrane damage in other membrane systems such as lipid vesicles, animal cells, and organelles.
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Affiliation(s)
- Neha Nanajkar
- Department of Biology, University of Maryland, College Park, MD 20742, USA
| | - Lekhana S Mruthyunjaya
- Department of Food Technology, M.S. Ramaiah University of Applied Sciences, Bangalore 560054, India
| | - Deepesh Nagarajan
- Department of Biotechnology, M.S. Ramaiah University of Applied Sciences, Bangalore 560054, India
- Department of Microbiology, St. Xavier's College, Mumbai 400001, India
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7
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Abu Quba AA, Goebel MO, Karagulyan M, Miltner A, Kästner M, Bachmann J, Schaumann GE, Diehl D. Changes in cell surface properties of Pseudomonas fluorescens by adaptation to NaCl induced hypertonic stress. FEMS MICROBES 2022; 4:xtac028. [PMID: 37333443 PMCID: PMC10169395 DOI: 10.1093/femsmc/xtac028] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Revised: 10/26/2022] [Accepted: 12/05/2022] [Indexed: 10/12/2023] Open
Abstract
Determination of the effect of water stress on the surface properties of bacteria is crucial to study bacterial induced soil water repellency. Changes in the environmental conditions may affect several properties of bacteria such as the cell hydrophobicity and morphology. Here, we study the influence of adaptation to hypertonic stress on cell wettability, shape, adhesion, and surface chemical composition of Pseudomonas fluorescens. From this we aim to discover possible relations between the changes in wettability of bacterial films studied by contact angle and single cells studied by atomic and chemical force microscopy (AFM, CFM), which is still lacking. We show that by stress the adhesion forces of the cell surfaces towards hydrophobic functionalized probes increase while they decrease towards hydrophilic functionalized tips. This is consistent with the contact angle results. Further, cell size shrunk and protein content increased upon stress. The results suggest two possible mechanisms: Cell shrinkage is accompanied by the release of outer membrane vesicles by which the protein to lipid ratio increases. The higher protein content increases the rigidity and the number of hydrophobic nano-domains per surface area.
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Affiliation(s)
- Abd Alaziz Abu Quba
- Institute of Environmental Sciences, Rheinland-pfälzische Technische Universität Kaiserslauter-Landau, RPTU in Landau, Fortstrasse 7, 76829 Landau, Germany
| | - Marc-Oliver Goebel
- Institute of Soil Science, Leibniz Universität Hannover, Herrenhäuser Straße 2, 30419 Hannover, Germany
| | - Mariam Karagulyan
- Helmholtz Centre for Environmental Research - UFZ, Department of Environmental Biotechnology, Permoserstraße 15, 04318 Leipzig, Germany
| | - Anja Miltner
- Helmholtz Centre for Environmental Research - UFZ, Department of Environmental Biotechnology, Permoserstraße 15, 04318 Leipzig, Germany
| | - Matthias Kästner
- Helmholtz Centre for Environmental Research - UFZ, Department of Environmental Biotechnology, Permoserstraße 15, 04318 Leipzig, Germany
| | - Jörg Bachmann
- Institute of Soil Science, Leibniz Universität Hannover, Herrenhäuser Straße 2, 30419 Hannover, Germany
| | - Gabriele E Schaumann
- Institute of Environmental Sciences, Rheinland-pfälzische Technische Universität Kaiserslauter-Landau, RPTU in Landau, Fortstrasse 7, 76829 Landau, Germany
| | - Doerte Diehl
- Institute of Environmental Sciences, Rheinland-pfälzische Technische Universität Kaiserslauter-Landau, RPTU in Landau, Fortstrasse 7, 76829 Landau, Germany
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8
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Singh S, Wilksch JJ, Dunstan RA, Mularski A, Wang N, Hocking D, Jebeli L, Cao H, Clements A, Jenney AWJ, Lithgow T, Strugnell RA. LPS O Antigen Plays a Key Role in Klebsiella pneumoniae Capsule Retention. Microbiol Spectr 2022; 10:e0151721. [PMID: 35913154 PMCID: PMC9431683 DOI: 10.1128/spectrum.01517-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Accepted: 06/14/2022] [Indexed: 11/24/2022] Open
Abstract
Despite the importance of encapsulation in bacterial pathogenesis, the biochemical mechanisms and forces that underpin retention of capsule by encapsulated bacteria are poorly understood. In Gram-negative bacteria, there may be interactions between lipopolysaccharide (LPS) core and capsule polymers, between capsule polymers with retained acyl carriers and the outer membrane, and in some bacteria, between the capsule polymers and Wzi, an outer membrane protein lectin. Our transposon studies in Klebsiella pneumoniae B5055 identified additional genes that, when insertionally inactivated, resulted in reduced encapsulation. Inactivation of the gene waaL, which encodes the ligase responsible for attaching the repeated O antigen of LPS to the LPS core, resulted in a significant reduction in capsule retention, measured by atomic force microscopy. This reduction in encapsulation was associated with increased sensitivity to human serum and decreased virulence in a murine model of respiratory infection and, paradoxically, with increased biofilm formation. The capsule in the WaaL mutant was physically smaller than that of the Wzi mutant of K. pneumoniae B5055. These results suggest that interactions between surface carbohydrate polymers may enhance encapsulation, a key phenotype in bacterial virulence, and provide another target for the development of antimicrobials that may avoid resistance issues associated with growth inhibition. IMPORTANCE Bacterial capsules, typically comprised of complex sugars, enable pathogens to avoid key host responses to infection, including phagocytosis. These capsules are synthesized within the bacteria, exported through the outer envelope, and then secured to the external surface of the organism by a force or forces that are incompletely described. This study shows that in the important hospital pathogen Klebsiella pneumoniae, the polysaccharide capsule is retained by interactions with other surface sugars, especially the repeated sugar molecule of the LPS molecule in Gram-negative bacteria known as "O antigen." This O antigen is joined to the LPS molecule by ligation, and loss of the enzyme responsible for ligation, a protein called WaaL, results in reduced encapsulation. Since capsules are essential to the virulence of many pathogens, WaaL might provide a target for new antimicrobial development, critical to the control of pathogens like K. pneumoniae that have become highly drug resistant.
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Affiliation(s)
- Shweta Singh
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia
| | - Jonathan J. Wilksch
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia
- Infection and Immunity Program, Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, Victoria, Australia
| | - Rhys A. Dunstan
- Infection and Immunity Program, Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, Victoria, Australia
| | - Anna Mularski
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia
| | - Nancy Wang
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia
| | - Dianna Hocking
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia
| | - Leila Jebeli
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia
| | - Hanwei Cao
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia
| | - Abigail Clements
- Department of Life Sciences, Imperial College London, London, United Kingdom
| | - Adam W. J. Jenney
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia
| | - Trevor Lithgow
- Infection and Immunity Program, Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, Victoria, Australia
| | - Richard A. Strugnell
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia
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9
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Ghazal F, Farooq S, Wahab AT, Maharjan R, Zafar H, Siddiqui H, Shafi S, Choudhary MI. Identification of quinoline derivatives as growth inhibitors of MDR pathogen Klebsiella pneumoniae. Future Microbiol 2022; 17:843-859. [PMID: 35796056 DOI: 10.2217/fmb-2021-0111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Aims: This study was aimed to identify compounds with significant inhibitory potential against multidrug-resistant (MDR), multidrug-sensitive, and clinical isolates of Klebsiella pneumoniae. Materials & methods: Antibacterial activity of the nitroquinoline derivatives was assessed by micro-plate Alamar Blue assay. Results: Nitroquinoline derivatives 9, 11 and 14 showed inhibitory activity against MDR K. pneumoniae. Docking studies of these compounds with topoisomerase IV of K. pneumonia indicated the interactions of these compounds at the active site residues of enzyme near to cofactor (Mg+2). Furthermore, compound 11 was identified as a reactive oxygen species (ROS) inducer. None of the compounds showed hemolytic effect. Conclusion: This study was designed to identify compounds active against MDR K. pneumoniae which causes infections, such as pneumonia and urinary tract infections.
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Affiliation(s)
- Farzeen Ghazal
- HEJ Research Institute of Chemistry, International Center for Chemical and Biological Sciences, University of Karachi, Karachi, 75270, Pakistan
| | - Saba Farooq
- Dr Panjwani Center for Molecular Medicine and Drug Research, International Center of Chemical and Biological Sciences, University of Karachi, Karachi, 75270, Pakistan
| | - Atia-Tul Wahab
- Dr Panjwani Center for Molecular Medicine and Drug Research, International Center of Chemical and Biological Sciences, University of Karachi, Karachi, 75270, Pakistan
| | - Rukesh Maharjan
- HEJ Research Institute of Chemistry, International Center for Chemical and Biological Sciences, University of Karachi, Karachi, 75270, Pakistan
| | - Humaira Zafar
- Dr Panjwani Center for Molecular Medicine and Drug Research, International Center of Chemical and Biological Sciences, University of Karachi, Karachi, 75270, Pakistan
| | - Hina Siddiqui
- HEJ Research Institute of Chemistry, International Center for Chemical and Biological Sciences, University of Karachi, Karachi, 75270, Pakistan
| | - Sara Shafi
- HEJ Research Institute of Chemistry, International Center for Chemical and Biological Sciences, University of Karachi, Karachi, 75270, Pakistan
| | - M I Choudhary
- HEJ Research Institute of Chemistry, International Center for Chemical and Biological Sciences, University of Karachi, Karachi, 75270, Pakistan.,Dr Panjwani Center for Molecular Medicine and Drug Research, International Center of Chemical and Biological Sciences, University of Karachi, Karachi, 75270, Pakistan.,Department of Biochemistry, Faculty of Science, King Abdulaziz University, Jeddah, 21589, Saudi Arabia
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10
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Maggi S, Ferrari A, Yabre K, Bonini AA, Rivetti C, Folli C. Strategies to Investigate Membrane Damage, Nucleoid Condensation, and RNase Activity of Bacterial Toxin-Antitoxin Systems. Methods Protoc 2021; 4:mps4040071. [PMID: 34698227 PMCID: PMC8544347 DOI: 10.3390/mps4040071] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Revised: 09/26/2021] [Accepted: 10/02/2021] [Indexed: 11/23/2022] Open
Abstract
A large number of bacterial toxin–antitoxin (TA) systems have been identified so far and different experimental approaches have been explored to investigate their activity and regulation both in vivo and in vitro. Nonetheless, a common feature of these methods is represented by the difficulty in cell transformation, culturing, and stability of the transformants, due to the expression of highly toxic proteins. Recently, in dealing with the type I Lpt/RNAII and the type II YafQ/DinJ TA systems, we encountered several of these problems that urged us to optimize methodological strategies to study the phenotype of recombinant Escherichia coli host cells. In particular, we have found conditions to tightly repress toxin expression by combining the pET expression system with the E. coli C41(DE3) pLysS strain. To monitor the RNase activity of the YafQ toxin, we developed a fluorescence approach based on Thioflavin-T which fluoresces brightly when complexed with bacterial RNA. Fluorescence microscopy was also applied to reveal loss of membrane integrity associated with the activity of the type I toxin Lpt, by using DAPI and ethidium bromide to selectively stain cells with impaired membrane permeability. We further found that atomic force microscopy can readily be employed to characterize toxin-induced membrane damages.
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Affiliation(s)
- Stefano Maggi
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, 43124 Parma, Italy; (S.M.); (A.A.B.)
| | - Alberto Ferrari
- Department of Food and Drug, University of Parma, 43124 Parma, Italy; (A.F.); (K.Y.)
| | - Korotoum Yabre
- Department of Food and Drug, University of Parma, 43124 Parma, Italy; (A.F.); (K.Y.)
| | - Aleksandra Anna Bonini
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, 43124 Parma, Italy; (S.M.); (A.A.B.)
| | - Claudio Rivetti
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, 43124 Parma, Italy; (S.M.); (A.A.B.)
- Correspondence: (C.R.); (C.F.)
| | - Claudia Folli
- Department of Food and Drug, University of Parma, 43124 Parma, Italy; (A.F.); (K.Y.)
- Correspondence: (C.R.); (C.F.)
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11
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Antezana PE, Municoy S, Bellino MG, Martini MF, Desimone MF. Nanodelivery of the Gramicidin Peptide for Enhancing Antimicrobial Activity. EUR J LIPID SCI TECH 2021. [DOI: 10.1002/ejlt.202000389] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Pablo E. Antezana
- Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Instituto de Química y Metabolismo del Fármaco (IQUIMEFA) Facultad de Farmacia y Bioquímica Junín 956, (1113) Buenos Aires Argentina
| | - Sofia Municoy
- Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Instituto de Química y Metabolismo del Fármaco (IQUIMEFA) Facultad de Farmacia y Bioquímica Junín 956, (1113) Buenos Aires Argentina
| | - Martín G. Bellino
- Instituto de Nanociencia y Nanotecnología – Comisión Nacional de Energía Atómica y Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) Av. General Paz 1499, (1650) San Martín Argentina
| | - M. Florencia Martini
- Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Instituto de Química y Metabolismo del Fármaco (IQUIMEFA) Facultad de Farmacia y Bioquímica Junín 956, (1113) Buenos Aires Argentina
| | - Martín F. Desimone
- Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Instituto de Química y Metabolismo del Fármaco (IQUIMEFA) Facultad de Farmacia y Bioquímica Junín 956, (1113) Buenos Aires Argentina
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12
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Ilangumaran Ponmalar I, Ayappa KG, Basu JK. Bacterial protein listeriolysin O induces nonmonotonic dynamics because of lipid ejection and crowding. Biophys J 2021; 120:3040-3049. [PMID: 34214525 DOI: 10.1016/j.bpj.2021.06.014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 05/27/2021] [Accepted: 06/02/2021] [Indexed: 01/15/2023] Open
Abstract
Membrane-bound protein complexes involving pore forming toxins (PFTs) released by virulent bacteria are known to form transmembrane pores leading to host cell lysis. Developing alternative strategies against PFT mediated bacterial virulence factors requires an understanding of the cellular membrane response. However, membrane disruption and related lipid reorganization events during attack by PFTs remain largely unexplored. We report counterintuitive and nonmonotonic variations in lipid diffusion, measured using confocal fluorescence correlation spectroscopy, due to interplay of lipid ejection and crowding by membrane-bound oligomers of a prototypical cholesterol-dependent cytolysin, listeriolysin O (LLO). The observed dynamical crossover is correlated with concentration dependent transitions of LLO oligomeric state populations from rings to arc-like pore complexes, predicted using a proposed two-state free area-based diffusion model. At low PFT concentrations, a hitherto unexplored regime of increased lipid diffusivity is attributed to lipid ejection events because of a preponderance of ring-like pore states. At higher protein concentrations in which membrane-inserted arc-like pores dominate, lipid ejection is less efficient and the ensuing crowding results in a lowering of lipid diffusion. These variations in lipid dynamics are corroborated by macroscopic rheological response measurements of PFT bound vesicles. Our study correlates PFT oligomeric state transitions, membrane remodeling, and mechanical property variations, providing unique insights into the pore forming mechanisms of cholesterol-dependent cytolysins.
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Affiliation(s)
| | - K Ganapathy Ayappa
- Center for BioSystems Science and Engineering Bengaluru, India; Department of Chemical Engineering Bengaluru, India.
| | - Jaydeep K Basu
- Department of Physics, Indian Institute of Science, Bengaluru, India.
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13
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Bertrand B, Garduño-Juárez R, Munoz-Garay C. Estimation of pore dimensions in lipid membranes induced by peptides and other biomolecules: A review. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2021; 1863:183551. [PMID: 33465367 DOI: 10.1016/j.bbamem.2021.183551] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 12/31/2020] [Accepted: 01/04/2021] [Indexed: 02/07/2023]
Abstract
The cytoplasmic membrane is one of the most frequent cell targets of antimicrobial peptides (AMPs) and other biomolecules. Understanding the mechanism of action of AMPs at the molecular level is of utmost importance for designing of new membrane-specific molecules. In particular, the formation of pores, the structure and size of these pores are of great interest and require nanoscale resolution approaches, therefore, biophysical strategies are essential to achieve an understanding of these processes at this scale. In the case of membrane active peptides, pore formation or general membrane disruption is usually the last step before cell death, and so, pore size is generally directly associated to pore structure and stability and loss of cellular homeostasis, implicated in overall peptide activity. Up to date, there has not been a critical review discussing the methods that can be used specifically for estimating the pore dimensions induced by membrane active peptides. In this review we discuss the scope, relevance and popularity of the different biophysical techniques such as liposome leakage experiments, advanced microscopy, neutron or X-ray scattering, electrophysiological techniques and molecular dynamics studies, all of them useful for determining pore structure and dimension.
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Affiliation(s)
- Brandt Bertrand
- Instituto de Ciencias Físicas, Universidad Nacional Autónoma de México (ICF-UNAM), Avenida Universidad 2001, Chamilpa, 62210 Cuernavaca, Morelos, Mexico
| | - Ramón Garduño-Juárez
- Instituto de Ciencias Físicas, Universidad Nacional Autónoma de México (ICF-UNAM), Avenida Universidad 2001, Chamilpa, 62210 Cuernavaca, Morelos, Mexico
| | - Carlos Munoz-Garay
- Instituto de Ciencias Físicas, Universidad Nacional Autónoma de México (ICF-UNAM), Avenida Universidad 2001, Chamilpa, 62210 Cuernavaca, Morelos, Mexico.
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14
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Schäfer AB, Wenzel M. A How-To Guide for Mode of Action Analysis of Antimicrobial Peptides. Front Cell Infect Microbiol 2020; 10:540898. [PMID: 33194788 PMCID: PMC7604286 DOI: 10.3389/fcimb.2020.540898] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Accepted: 09/18/2020] [Indexed: 12/11/2022] Open
Abstract
Antimicrobial peptides (AMPs) are a promising alternative to classical antibiotics in the fight against multi-resistant bacteria. They are produced by organisms from all domains of life and constitute a nearly universal defense mechanism against infectious agents. No drug can be approved without information about its mechanism of action. In order to use them in a clinical setting, it is pivotal to understand how AMPs work. While many pore-forming AMPs are well-characterized in model membrane systems, non-pore-forming peptides are often poorly understood. Moreover, there is evidence that pore formation may not happen or not play a role in vivo. It is therefore imperative to study how AMPs interact with their targets in vivo and consequently kill microorganisms. This has been difficult in the past, since established methods did not provide much mechanistic detail. Especially, methods to study membrane-active compounds have been scarce. Recent advances, in particular in microscopy technology and cell biological labeling techniques, now allow studying mechanisms of AMPs in unprecedented detail. This review gives an overview of available in vivo methods to investigate the antibacterial mechanisms of AMPs. In addition to classical mode of action classification assays, we discuss global profiling techniques, such as genomic and proteomic approaches, as well as bacterial cytological profiling and other cell biological assays. We cover approaches to determine the effects of AMPs on cell morphology, outer membrane, cell wall, and inner membrane properties, cellular macromolecules, and protein targets. We particularly expand on methods to examine cytoplasmic membrane parameters, such as composition, thickness, organization, fluidity, potential, and the functionality of membrane-associated processes. This review aims to provide a guide for researchers, who seek a broad overview of the available methodology to study the mechanisms of AMPs in living bacteria.
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Affiliation(s)
| | - Michaela Wenzel
- Division of Chemical Biology, Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
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15
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Chen C, Li G, Cui X, Chen J, Yu Q, Zong C, Zhao Y, Xu M, Zhou S, Xu H. Mechanistic Investigation of a Self-Assembling Peptide against Escherichia coli. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:9800-9809. [PMID: 32787117 DOI: 10.1021/acs.langmuir.0c01311] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Because of their distinctive mode of action in targeting bacterial cell membranes, antimicrobial peptides (AMPs) are increasingly regarded as a potential candidate for the development of novel antibiotics to combat the wide spread of bacterial resistance. To date, understanding of the exact molecular process by which AMPs act on the real bacterial envelope remains challenging. Simultaneously, the aggregated state of AMPs upon interaction with bacterial envelopes is still elusive. Previously, we have demonstrated that the potent antibacterial activity of a designed surfactant-like peptide Ac-A9K-NH2 benefited greatly from its high self-assembling ability and appropriate self-assembled morphologies and sizes. By using high-resolution atomic force microscopy, we here not only follow the variations of the Escherichia coli cell envelope in the presence of Ac-A9K-NH2 but also characterize the peptide aggregates on the bacterial surface as well as on the substrate surface. The results, together with those from fluorescence, zeta potential, circular dichroism, and scanning electron microscopy measurements, indicate that both the positively charged peptide monomers and self-assembled nanostructures can directly act on the negatively charged bacterial surface, followed by their insertion into the bacterial membrane, the formation of surface nanopores, and membrane lysis. The mechanism of Ac-A9K-NH2 against E. coli is thus consistent with the detergent-like mode of action. This work enhances our mechanistic understanding of the antibacterial behaviors of self-assembling peptides that will be valuable in exploring their biomedical applications.
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Affiliation(s)
- Cuixia Chen
- Centre for Bioengineering and Biotechnology, China University of Petroleum (East China), 66 Changjiang West Road, Qingdao 266580, China
| | - Gongrang Li
- Drilling Technology Research Institute, Sinopec Shengli Oilfield Service Corporation, Dongying 257000, China
| | - Xuejing Cui
- Centre for Bioengineering and Biotechnology, China University of Petroleum (East China), 66 Changjiang West Road, Qingdao 266580, China
| | - Jiaxi Chen
- Centre for Bioengineering and Biotechnology, China University of Petroleum (East China), 66 Changjiang West Road, Qingdao 266580, China
| | - Qizhi Yu
- Centre for Bioengineering and Biotechnology, China University of Petroleum (East China), 66 Changjiang West Road, Qingdao 266580, China
| | - Cheng Zong
- Centre for Bioengineering and Biotechnology, China University of Petroleum (East China), 66 Changjiang West Road, Qingdao 266580, China
| | - Yurong Zhao
- Centre for Bioengineering and Biotechnology, China University of Petroleum (East China), 66 Changjiang West Road, Qingdao 266580, China
| | - Minglu Xu
- Centre for Bioengineering and Biotechnology, China University of Petroleum (East China), 66 Changjiang West Road, Qingdao 266580, China
| | - Shasha Zhou
- Centre for Bioengineering and Biotechnology, China University of Petroleum (East China), 66 Changjiang West Road, Qingdao 266580, China
| | - Hai Xu
- Centre for Bioengineering and Biotechnology, China University of Petroleum (East China), 66 Changjiang West Road, Qingdao 266580, China
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16
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Hammond K, Ryadnov MG, Hoogenboom BW. Atomic force microscopy to elucidate how peptides disrupt membranes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1863:183447. [PMID: 32835656 DOI: 10.1016/j.bbamem.2020.183447] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Revised: 07/30/2020] [Accepted: 08/13/2020] [Indexed: 12/24/2022]
Abstract
Atomic force microscopy is an increasingly attractive tool to study how peptides disrupt membranes. Often performed on reconstituted lipid bilayers, it provides access to time and length scales that allow dynamic investigations with nanometre resolution. Over the last decade, AFM studies have enabled visualisation of membrane disruption mechanisms by antimicrobial or host defence peptides, including peptides that target malignant cells and biofilms. Moreover, the emergence of high-speed modalities of the technique broadens the scope of investigations to antimicrobial kinetics as well as the imaging of peptide action on live cells in real time. This review describes how methodological advances in AFM facilitate new insights into membrane disruption mechanisms.
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Affiliation(s)
- Katharine Hammond
- National Physical Laboratory, Hampton Road, Teddington TW11 0LW, UK; London Centre for Nanotechnology, University College London, London WC1H 0AH, UK; Department of Physics & Astronomy, University College London, London WC1E 6BT, UK.
| | - Maxim G Ryadnov
- National Physical Laboratory, Hampton Road, Teddington TW11 0LW, UK; Department of Physics, King's College London, Strand Lane, London WC2R 2LS, UK.
| | - Bart W Hoogenboom
- London Centre for Nanotechnology, University College London, London WC1H 0AH, UK; Department of Physics & Astronomy, University College London, London WC1E 6BT, UK.
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17
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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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18
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Tamayo L, Melo F, Caballero L, Hamm E, Díaz M, Leal MS, Guiliani N, Urzúa MD. Does Bacterial Elasticity Affect Adhesion to Polymer Fibers? ACS APPLIED MATERIALS & INTERFACES 2020; 12:14507-14517. [PMID: 32118396 DOI: 10.1021/acsami.9b21060] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The factors governing bacterial adhesion to substrates with different topographies are still not fully identified. The present work seeks to elucidate for the first time and with quantitative data the roles of bacterial elasticity and shape and substrate topography in bacterial adhesion. With this aim, populations of three bacterial species, P. aeruginosa DSM 22644, B. subtilis DSM 10, and S. aureus DSM 20231 adhered on flat substrates covered with electrospun polycaprolactone fibers of different diameters ranging from 0.4 to 5.5 μm are counted. Populations of bacterial cells are classified according to the preferred binding sites of the bacteria to the substrate. The colloidal probe technique was used to assess the stiffness of the bacteria and bacteria-polymer surface adhesion energy. A theoretical model is developed to interpret the observed populations in terms of a balance between stiffness and adhesion energy of the bacteria. The model, which also incorporates the radius of the fiber and the size and shape of the bacteria, predicts increased adhesion for a low level of stiffness and for a larger number of available bacteria-fiber contact points. Te adhesive propensity of bacteria depends in a nontrivial way on the radius of the fibers due to the random arrangement of fibers.
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Affiliation(s)
- Laura Tamayo
- Departamento de Química, Facultad de Ciencias, Universidad de Chile, Las Palmeras, Santiago 3425, Chile
| | - Francisco Melo
- Departamento Física, Facultad de Ciencia, Universidad de Santiago de Chile, Avenida Ecuador, Santiago 3493, Chile
- Center for Soft Matter Research, SMAT-C, Avenida Libertador Bernardo O'Higgins, Santiago 3363, Chile
| | - Leonardo Caballero
- Departamento Física, Facultad de Ciencia, Universidad de Santiago de Chile, Avenida Ecuador, Santiago 3493, Chile
- Center for Soft Matter Research, SMAT-C, Avenida Libertador Bernardo O'Higgins, Santiago 3363, Chile
| | - Eugenio Hamm
- Departamento Física, Facultad de Ciencia, Universidad de Santiago de Chile, Avenida Ecuador, Santiago 3493, Chile
| | - M Díaz
- Laboratorio de Comunicación Bacteriana, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Las Palmeras, Ñuñoa, Santiago 3425, Chile
| | - M S Leal
- Departamento de Química, Facultad de Ciencias, Universidad de Chile, Las Palmeras, Santiago 3425, Chile
| | - N Guiliani
- Laboratorio de Comunicación Bacteriana, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Las Palmeras, Ñuñoa, Santiago 3425, Chile
| | - M D Urzúa
- Departamento de Química, Facultad de Ciencias, Universidad de Chile, Las Palmeras, Santiago 3425, Chile
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19
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Munusamy S, Conde R, Bertrand B, Munoz-Garay C. Biophysical approaches for exploring lipopeptide-lipid interactions. Biochimie 2020; 170:173-202. [PMID: 31978418 PMCID: PMC7116911 DOI: 10.1016/j.biochi.2020.01.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Accepted: 01/19/2020] [Indexed: 02/07/2023]
Abstract
In recent years, lipopeptides (LPs) have attracted a lot of attention in the pharmaceutical industry due to their broad-spectrum of antimicrobial activity against a variety of pathogens and their unique mode of action. This class of compounds has enormous potential for application as an alternative to conventional antibiotics and for pest control. Understanding how LPs work from a structural and biophysical standpoint through investigating their interaction with cell membranes is crucial for the rational design of these biomolecules. Various analytical techniques have been developed for studying intramolecular interactions with high resolution. However, these tools have been barely exploited in lipopeptide-lipid interactions studies. These biophysical approaches would give precise insight on these interactions. Here, we reviewed these state-of-the-art analytical techniques. Knowledge at this level is indispensable for understanding LPs activity and particularly their potential specificity, which is relevant information for safe application. Additionally, the principle of each analytical technique is presented and the information acquired is discussed. The key challenges, such as the selection of the membrane model are also been briefly reviewed. A brief overview of topics to understand the generalities of lipopeptide (LP) science. Main analytical techniques used to reveal the interaction and the distorting effect of LP on artificial membranes. Guidelines for selecting of the most adequate membrane models for the given analytical technique.
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Affiliation(s)
- Sathishkumar Munusamy
- Instituto de Ciencias Físicas, Universidad Nacional Autónoma de México, Av. Universidad 2001, Col. Chamilpa, 62210, Cuernavaca, Mexico
| | - Renaud Conde
- Centro de Investigación Sobre Enfermedades Infecciosas, Instituto Nacional de Salud Pública, Cuernavaca, Morelos, Mexico
| | - Brandt Bertrand
- Instituto de Ciencias Físicas, Universidad Nacional Autónoma de México, Av. Universidad 2001, Col. Chamilpa, 62210, Cuernavaca, Mexico
| | - Carlos Munoz-Garay
- Instituto de Ciencias Físicas, Universidad Nacional Autónoma de México, Av. Universidad 2001, Col. Chamilpa, 62210, Cuernavaca, Mexico.
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20
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Zou M, Tao W, Ye X, Liu D. Evaluation of antimicrobial and antibiofilm properties of proanthocyanidins from Chinese bayberry ( Myrica rubra Sieb. et Zucc.) leaves against Staphylococcus epidermidis. Food Sci Nutr 2020; 8:139-149. [PMID: 31993140 PMCID: PMC6977480 DOI: 10.1002/fsn3.1283] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2019] [Revised: 09/25/2019] [Accepted: 10/09/2019] [Indexed: 12/17/2022] Open
Abstract
Staphylococcus epidermidis has emerged in recent years as one of the most important opportunistic pathogens owing to its ability to attach to processing surfaces in the food industry. Demands of foodstuffs maintaining microbiological safety and stability enhance the need to develop natural antimicrobial agents as food preservatives. Proanthocyanidins from Chinese bayberry leaves (BLPs) belonging to the class of polyphenols promise to be a potential antibacterial material against bacterial adhesion and biofilm formation. The aim of the present study was to investigate the effects of BLPs on S. epidermidis growth and biofilm formation. BLPs possessed antimicrobial activity with MIC and MBC of 320 and 640 μg/ml, respectively. Scanning electron microscopy, transmission electron microscopy, and flow cytometry analysis revealed a loss of the cell structure and function after treatment of BLPs, evidenced by cell membrane hyperpolarization and changes in cellular morphology. BLPs inhibited the biofilm formation by S. epidermidis on polystyrene microplates. Atomic force microscopy analysis showed that BLPs could decrease the stiffness and adhesion force of the cell envelope, which might account for the inhibition of biofilm formation. In summary, this study indicated that BLPs have potential to be developed as natural preservatives to control S. epidermidis in foods.
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Affiliation(s)
- Mingming Zou
- National Engineering Laboratory of Intelligent Food Technology and EquipmentZhejiang Key Laboratory for Agro‐Food ProcessingCollege of Biosystems Engineering and Food ScienceFuli Institute of Food ScienceZhejiang UniversityHangzhouChina
| | - Wenyang Tao
- National Engineering Laboratory of Intelligent Food Technology and EquipmentZhejiang Key Laboratory for Agro‐Food ProcessingCollege of Biosystems Engineering and Food ScienceFuli Institute of Food ScienceZhejiang UniversityHangzhouChina
| | - Xingqian Ye
- National Engineering Laboratory of Intelligent Food Technology and EquipmentZhejiang Key Laboratory for Agro‐Food ProcessingCollege of Biosystems Engineering and Food ScienceFuli Institute of Food ScienceZhejiang UniversityHangzhouChina
| | - Donghong Liu
- National Engineering Laboratory of Intelligent Food Technology and EquipmentZhejiang Key Laboratory for Agro‐Food ProcessingCollege of Biosystems Engineering and Food ScienceFuli Institute of Food ScienceZhejiang UniversityHangzhouChina
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21
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Theansungnoen T, Jangpromma N, Anwised P, Daduang S, Fukumori Y, Taoka A, Klaynongsruang S. Membranolytic Effects of KT2 on Gram-Negative Escherichia coli Evaluated by Atomic Force Microscopy. APPL BIOCHEM MICRO+ 2019. [DOI: 10.1134/s0003683819050144] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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22
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Phanphak S, Georgiades P, Li R, King J, Roberts IS, Waigh TA. Super-Resolution Fluorescence Microscopy Study of the Production of K1 Capsules by Escherichia coli: Evidence for the Differential Distribution of the Capsule at the Poles and the Equator of the Cell. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:5635-5646. [PMID: 30916568 PMCID: PMC6492954 DOI: 10.1021/acs.langmuir.8b04122] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The production of Escherichia coli K1 serotype capsule was investigated using direct stochastic optical reconstruction microscopy with live bacteria and graphene oxide-coated coverslips, overcoming many morphological artifacts found in other high-resolution imaging techniques. Super-resolution fluorescence images showed that the K1 capsular polysaccharide is not uniformly distributed on the cell surface, as previously thought. These studies demonstrated that on the cell surfaces the K1 capsule at the poles had bimodal thicknesses of 238 ± 41 and 323 ± 62 nm, whereas at the equator, there was a monomodal thickness of 217 ± 29 nm. This bimodal variation was also observed in high-pressure light-scattering chromatography measurements of purified K1 capsular polysaccharide. Particle tracking demonstrated that the formation of the capsule was dominated by the expansion of lyso-phosphatidylglycerol (lyso-PG) rafts that anchor the capsular polysaccharide in the outer membrane, and the expansion of these rafts across the cell surface was driven by new material transported through the capsular biosynthesis channels. The discovery of thicker capsules at the poles of the cell will have implications in mediating interactions between the bacterium and its immediate environment.
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Affiliation(s)
- Sorasak Phanphak
- School
of Physics and Astronomy, Schuster Building and Photon Science Institute, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K.
| | - Pantelis Georgiades
- School
of Physics and Astronomy, Schuster Building and Photon Science Institute, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K.
| | - Ruiheng Li
- School
of Physics and Astronomy, Schuster Building and Photon Science Institute, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K.
| | - Jane King
- Faculty
of Biology, Medicine and Health, Michael Smith Building, The University of Manchester, Dover Street, Manchester M13 9PL, U.K.
| | - Ian S. Roberts
- Faculty
of Biology, Medicine and Health, Michael Smith Building, The University of Manchester, Dover Street, Manchester M13 9PL, U.K.
- E-mail: (I.S.R.)
| | - Thomas A. Waigh
- School
of Physics and Astronomy, Schuster Building and Photon Science Institute, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K.
- E-mail: (T.A.W.)
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23
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Krishnan R S, Satheesan R, Puthumadathil N, Kumar KS, Jayasree P, Mahendran KR. Autonomously Assembled Synthetic Transmembrane Peptide Pore. J Am Chem Soc 2019; 141:2949-2959. [DOI: 10.1021/jacs.8b09973] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
- Smrithi Krishnan R
- Membrane Biology Laboratory, Interdisciplinary Research Program, Rajiv Gandhi Centre for Biotechnology, Thiruvananthapuram 695014, India
| | - Remya Satheesan
- Membrane Biology Laboratory, Interdisciplinary Research Program, Rajiv Gandhi Centre for Biotechnology, Thiruvananthapuram 695014, India
| | - Neethu Puthumadathil
- Membrane Biology Laboratory, Interdisciplinary Research Program, Rajiv Gandhi Centre for Biotechnology, Thiruvananthapuram 695014, India
| | - K. Santhosh Kumar
- Membrane Biology Laboratory, Interdisciplinary Research Program, Rajiv Gandhi Centre for Biotechnology, Thiruvananthapuram 695014, India
| | - Poornendhu Jayasree
- Membrane Biology Laboratory, Interdisciplinary Research Program, Rajiv Gandhi Centre for Biotechnology, Thiruvananthapuram 695014, India
| | - Kozhinjampara R. Mahendran
- Membrane Biology Laboratory, Interdisciplinary Research Program, Rajiv Gandhi Centre for Biotechnology, Thiruvananthapuram 695014, India
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24
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Abstract
Antimicrobial peptides (AMPs) are one of the most promising alternatives to conventional antibiotics. Atomic force microscopy (AFM), as imaging and force spectroscopy tool, has been applied to study their mechanism of action and development. Here, we describe different methods to be applied in the study of AMP effects on bacteria, either by imaging or by force spectroscopy studies, essential to underlie their action and to identify possibly outcomes of the same.
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Affiliation(s)
- Marco M Domingues
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal.
| | - Mário R Felício
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal
| | - Sónia Gonçalves
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal.
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25
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Gulyuk AV, LaJeunesse DR, Collazo R, Ivanisevic A. Characterization of Pseudomonas aeruginosa Films on Different Inorganic Surfaces before and after UV Light Exposure. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:10806-10815. [PMID: 30122052 DOI: 10.1021/acs.langmuir.8b02079] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The changes of the surface properties of Au, GaN, and SiO x after UV light irradiation were used to actively influence the process of formation of Pseudomonas aeruginosa films. The interfacial properties of the substrates were characterized by X-ray photoelectron spectroscopy and atomic force microscopy. The changes in the P. aeruginosa film properties were accessed by analyzing adhesion force maps and quantifying the intracellular Ca2+ concentration. The collected analysis indicates that the alteration of the inorganic materials' surface chemistry can lead to differences in biofilm formation and variable response from P. aeruginosa cells.
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Affiliation(s)
- Alexey V Gulyuk
- Department of Materials Science and Engineering , North Carolina State University , Raleigh , North Carolina 27695 , United States
| | - Dennis R LaJeunesse
- Joint School of Nanoscience and Nanoengineering , University of North Carolina-Greensboro and North Carolina A&T State University , Greensboro , North Carolina 27401 , United States
| | - Ramon Collazo
- Department of Materials Science and Engineering , North Carolina State University , Raleigh , North Carolina 27695 , United States
| | - Albena Ivanisevic
- Department of Materials Science and Engineering , North Carolina State University , Raleigh , North Carolina 27695 , United States
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26
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Laskowski D, Strzelecki J, Pawlak K, Dahm H, Balter A. Effect of ampicillin on adhesive properties of bacteria examined by atomic force microscopy. Micron 2018; 112:84-90. [DOI: 10.1016/j.micron.2018.05.005] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2018] [Revised: 05/04/2018] [Accepted: 05/04/2018] [Indexed: 01/05/2023]
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27
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Antimicrobial peptides: biochemical determinants of activity and biophysical techniques of elucidating their functionality. World J Microbiol Biotechnol 2018; 34:62. [PMID: 29651655 DOI: 10.1007/s11274-018-2444-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Accepted: 04/05/2018] [Indexed: 10/17/2022]
Abstract
Antimicrobial peptides (AMPs) have been established over millennia as powerful components of the innate immune system of many organisms. Due to their broad spectrum of activity and the development of host resistance against them being unlikely, AMPs are strong candidates for controlling drug-resistant pathogenic microbial pathogens. AMPs cause cell death through several independent or cooperative mechanisms involving membrane lysis, non-lytic activity, and/or intracellular mechanisms. Biochemical determinants such as peptide length, primary sequence, charge, secondary structure, hydrophobicity, amphipathicity and host cell membrane composition together influence the biological activities of peptides. A number of biophysical techniques have been used in recent years to study the mechanisms of action of AMPs. This work appraises the molecular parameters that determine the biocidal activity of AMPs and overviews their mechanisms of actions and the diverse biochemical, biophysical and microscopy techniques utilised to elucidate these.
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Zhu S, Sani M, Separovic F. Interaction of cationic antimicrobial peptides from Australian frogs with lipid membranes. Pept Sci (Hoboken) 2018. [DOI: 10.1002/pep2.24061] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Affiliation(s)
- Shiying Zhu
- School of ChemistryBio21 Institute, University of MelbourneMelbourne VIC3010 Australia
| | - Marc‐Antoine Sani
- School of ChemistryBio21 Institute, University of MelbourneMelbourne VIC3010 Australia
| | - Frances Separovic
- School of ChemistryBio21 Institute, University of MelbourneMelbourne VIC3010 Australia
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29
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Tran N, Hocquet M, Eon B, Sangwan P, Ratcliffe J, Hinton TM, White J, Ozcelik B, Reynolds NP, Muir BW. Non-lamellar lyotropic liquid crystalline nanoparticles enhance the antibacterial effects of rifampicin against Staphylococcus aureus. J Colloid Interface Sci 2018; 519:107-118. [PMID: 29486430 DOI: 10.1016/j.jcis.2018.02.048] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Revised: 02/15/2018] [Accepted: 02/15/2018] [Indexed: 01/01/2023]
Abstract
The fight against infection in an era of emerging antibiotic resistant bacteria is one of the grandest scientific challenges facing society today. Nano-carriers show great promise in improving the antibacterial activity of antibiotics as they are able to enhance their solubility, provide sustained release and reduce toxic side effects via specifically targeting infection sites. Here, we investigate the antibacterial effect of two lipidic nano-carriers that contain the poorly soluble antibiotic rifampicin in their bilayers. One nanoparticle is assembled solely from the lipid monoolein, thus is neutral at physiological pH and the other contains a mixture of monoolein and the cationic lipid N-[1-(2,3-Dioleoyloxy)propyl]-N,N,N-trimethylammonium methyl-sulfate (DOTAP), thus is positively charged. Our results show that rifampicin-loaded nanoparticles reduce the minimum inhibitory concentration against Staphylococcus aureus compared to rifampicin alone, however this reduction was most pronounced for the positively charged nanoparticles. Fluorescent microscopy revealed binding of all nanoparticles to the bacteria and enhanced binding was observed for the charged nanoparticles. This suggests that the cationic lipids promote electrostatic interactions with the negatively charged bacterial membrane. Förster resonance energy transfer demonstrated that the cationic charged nanoparticles were able to fuse with bacterial membranes whilst atomic force microscopy and transmission electron microscopy revealed structural damage to the bacterial membranes caused by the nanoparticles. Significantly, we identified a concentration window in which the nanoparticles exhibited antibacterial activity while not affecting HeLa and CHO cell viability. This ability to improve the efficacy of antibiotics without affecting their eukaryotic cytotoxicity is of significant importance for future development of nanomedicine based strategies to combat infections.
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Affiliation(s)
- Nhiem Tran
- School of Science, RMIT University, Melbourne, Victoria 3000, Australia.
| | - Marion Hocquet
- CSIRO Manufacturing, Clayton, Victoria 3168, Australia; Chimie Paris Tech, Paris, France
| | - Blandine Eon
- CSIRO Manufacturing, Clayton, Victoria 3168, Australia; Chimie Paris Tech, Paris, France
| | | | | | | | - Jacinta White
- CSIRO Manufacturing, Clayton, Victoria 3168, Australia
| | | | - Nicholas P Reynolds
- Swinburne University of Technology, ARC Training Centre for Biodevices, Faculty of Science, Engineering and Technology, Victoria 3122, Australia
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30
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Defining the Mechanical Determinants of Kingella kingae Adherence to Host Cells. J Bacteriol 2017; 199:JB.00314-17. [PMID: 28874408 DOI: 10.1128/jb.00314-17] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Accepted: 08/23/2017] [Indexed: 12/17/2022] Open
Abstract
Kingella kingae is an important pathogen in young children and initiates infection by colonizing the posterior pharynx. Adherence to pharyngeal epithelial cells is an important first step in the process of colonization. In the present study, we sought to elucidate the interplay of type IV pili (T4P), a trimeric autotransporter adhesin called Knh, and the polysaccharide capsule in K. kingae adherence to host cells. Using adherence assays performed under shear stress, we observed that a strain expressing only Knh was capable of higher levels of adherence than a strain expressing only T4P. Using atomic force microscopy and transmission electron microscopy (TEM), we established that the capsule had a mean depth of 700 nm and that Knh was approximately 110 nm long. Using cationic ferritin capsule staining and thin-section transmission electron microscopy, we found that when bacteria expressing retractile T4P were in close contact with host cells, the capsule was absent at the point of contact between the bacterium and the host cell membrane. In a T4P retraction-deficient mutant, the capsule depth remained intact and adherence levels were markedly reduced. These results support the following model: T4P make initial contact with the host cell and mediate low-strength adherence. T4P retract, pulling the organism closer to the host cell and displacing the capsule, allowing Knh to be exposed and mediate high-strength, tight adherence to the host cell surface. This report provides the first description of the mechanical displacement of capsule enabling intimate bacterial adherence to host cells.IMPORTANCE Adherence to host cells is an important first step in bacterial colonization and pathogenicity. Kingella kingae has three surface factors that are involved in adherence: type IV pili (T4P), a trimeric autotransporter adhesin called Knh, and a polysaccharide capsule. Our results suggest that T4P mediate initial contact and low-strength adherence to host cells. T4P retraction draws the bacterium closer to the host cell and causes the displacement of capsule. This displacement exposes Knh and allows Knh to mediate high-strength adherence to the host cell. This work provides new insight into the interplay of T4P, a nonpilus adhesin, and a capsule and their effects on bacterial adherence to host cells.
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31
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Oliveira M, Gomes-Alves AG, Sousa C, Mirta Marani M, Plácido A, Vale N, Delerue-Matos C, Gameiro P, Kückelhaus SAS, Tomas AM, S A Leite JR, Eaton P. Ocellatin-PT antimicrobial peptides: High-resolution microscopy studies in antileishmania models and interactions with mimetic membrane systems. Biopolymers 2017; 105:873-86. [PMID: 27463422 DOI: 10.1002/bip.22925] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Revised: 07/21/2016] [Accepted: 07/22/2016] [Indexed: 01/07/2023]
Abstract
Although the mechanism of action of antimicrobial peptides (AMPs) is not clear, they can interact electrostatically with the cell membranes of microorganisms. New ocellatin-PT peptides were recently isolated from the skin secretion of Leptodactylus pustulatus. The secondary structure of these AMPs and their effect on Leishmania infantum cells, and on different lipid surface models was characterized in this work. The results showed that all ocellatin-PT peptides have an α-helix structure and five of them (PT3, PT4, PT6 to PT8) have leishmanicidal activity; PT1 and PT2 affected the cellular morphology of the parasites and showed greater affinity for leishmania and bacteria-mimicking lipid membranes than for those of mammals. The results show selectivity of ocellatin-PTs to the membranes of microorganisms and the applicability of biophysical methods to clarify the interaction of AMPs with cell membranes.
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Affiliation(s)
- Mayara Oliveira
- Programa de Pós-Graduação em Medicina Tropical, Núcleo de Medicina Tropical, NMT, Faculdade de Medicina, Universidade de Brasília, Brasília, DF, Brazil.,Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, 4200, Portugal
| | - Ana Georgina Gomes-Alves
- IBMC, Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal.,UCIBIO, REQUIMTE, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, Porto, Portugal.,CEB, Centro de Engenharia Biológica, Universidade do Minho, Campus de Gualtar, Braga, 4710-057, Portugal
| | - Carla Sousa
- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, 4200, Portugal
| | - Mariela Mirta Marani
- PEEC ? CONICET, Consejo Nacional de Investigaciones Científicas y Técnicas, Puerto Madryn, Chubut, Argentina
| | - Alexandra Plácido
- REQUIMTE/LAQV, Instituto Superior de Engenharia do Instituto Politécnico do Porto, Porto, Portugal
| | - Nuno Vale
- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, 4200, Portugal
| | - Cristina Delerue-Matos
- REQUIMTE/LAQV, Instituto Superior de Engenharia do Instituto Politécnico do Porto, Porto, Portugal
| | - Paula Gameiro
- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, 4200, Portugal
| | - Selma A S Kückelhaus
- Programa de Pós-Graduação em Medicina Tropical, Núcleo de Medicina Tropical, NMT, Faculdade de Medicina, Universidade de Brasília, Brasília, DF, Brazil.,Departmento de Morfologia, Faculdade de Medicina, Universidade de Brasília, Brasilia, Brazil
| | - Ana M Tomas
- IBMC, Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal.,UCIBIO, REQUIMTE, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, Porto, Portugal.,ICBAS, Instituto de Ciencias Biomedicas Abel Salazar, Universidade do Porto, Porto, Portugal
| | - José Roberto S A Leite
- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, 4200, Portugal.,Departmento de Morfologia, Faculdade de Medicina, Universidade de Brasília, Brasilia, Brazil.,Núcleo de Pesquisa em Biodiversidade e Biotecnologia, Biotec, Campus Ministro Reis Velloso, Universidade Federal do Piauí, UFPI, Parnaiba, PI, Brazil
| | - Peter Eaton
- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, 4200, Portugal. .,Núcleo de Pesquisa em Biodiversidade e Biotecnologia, Biotec, Campus Ministro Reis Velloso, Universidade Federal do Piauí, UFPI, Parnaiba, PI, Brazil.
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32
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Wiedman G, Kim SY, Zapata-Mercado E, Wimley WC, Hristova K. pH-Triggered, Macromolecule-Sized Poration of Lipid Bilayers by Synthetically Evolved Peptides. J Am Chem Soc 2017; 139:937-945. [PMID: 28001058 PMCID: PMC5521809 DOI: 10.1021/jacs.6b11447] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
pH-triggered membrane-permeabilizing peptides could be exploited in a variety of applications, such as to enable cargo release from endosomes for cellular delivery, or as cancer therapeutics that selectively permeabilize the plasma membranes of malignant cells. Such peptides would be especially useful if they could enable the movement of macromolecules across membranes, a rare property in membrane-permeabilizing peptides. Here we approach this goal by using an orthogonal high-throughput screen of an iterative peptide library to identify peptide sequences that have the following two properties: (i) little synthetic lipid membrane permeabilization at physiological pH 7 at high peptide concentration and (ii) efficient formation of macromolecule-sized defects in synthetic lipid membranes at acidic pH 5 and low peptide concentration. The peptides we selected are remarkably potent macromolecular sized pore-formers at pH 5, while having little or no activity at pH 7, as intended. The action of these peptides likely relies on tight coupling between membrane partitioning, α-helix formation, and electrostatic repulsions between acidic side chains, which collectively drive a sharp pH-triggered transition between inactive and active configurations with apparent pKa values of 5.5-5.8. This work opens new doors to developing applications that utilize peptides with membrane-permeabilizing activities that are triggered by physiologically relevant decreases in pH.
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Affiliation(s)
- Gregory Wiedman
- Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, MD 21218
- Institute for NanoBioTechnology, Johns Hopkins University, Baltimore, MD 21218
| | - Sarah Y. Kim
- Graduate Program in Molecular Biophysics, Johns Hopkins University, Baltimore, MD 21218
- Institute for NanoBioTechnology, Johns Hopkins University, Baltimore, MD 21218
| | - Elmer Zapata-Mercado
- Graduate Program in Molecular Biophysics, Johns Hopkins University, Baltimore, MD 21218
- Institute for NanoBioTechnology, Johns Hopkins University, Baltimore, MD 21218
| | - William C. Wimley
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, New Orleans, LA, 70112
| | - Kalina Hristova
- Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, MD 21218
- Graduate Program in Molecular Biophysics, Johns Hopkins University, Baltimore, MD 21218
- Institute for NanoBioTechnology, Johns Hopkins University, Baltimore, MD 21218
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33
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Mularski A, Separovic F. Atomic Force Microscopy Studies of the Interaction of Antimicrobial Peptides with Bacterial Cells. Aust J Chem 2017. [DOI: 10.1071/ch16425] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Antimicrobial peptides (AMPs) are promising therapeutic alternatives to conventional antibiotics. Many AMPs are membrane-active but their mode of action in killing bacteria or in inhibiting their growth remains elusive. Recent studies indicate the mechanism of action depends on peptide structure and lipid components of the bacterial cell membrane. Owing to the complexity of working with living cells, most of these studies have been conducted with synthetic membrane systems, which neglect the possible role of bacterial surface structures in these interactions. In recent years, atomic force microscopy has been utilized to study a diverse range of biological systems under non-destructive, physiologically relevant conditions that yield in situ biophysical measurements of living cells. This approach has been applied to the study of AMP interaction with bacterial cells, generating data that describe how the peptides modulate various biophysical behaviours of individual bacteria, including the turgor pressure, cell wall elasticity, bacterial capsule thickness, and organization of bacterial adhesins.
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34
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Harrison PL, Heath GR, Johnson BR, Abdel-Rahman MA, Strong PN, Evans SD, Miller K. Phospholipid dependent mechanism of smp24, an α-helical antimicrobial peptide from scorpion venom. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2016; 1858:2737-2744. [DOI: 10.1016/j.bbamem.2016.07.018] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Revised: 07/06/2016] [Accepted: 07/27/2016] [Indexed: 12/27/2022]
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A nanomechanical study of the effects of colistin on the Klebsiella pneumoniae AJ218 capsule. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2016; 46:351-361. [DOI: 10.1007/s00249-016-1178-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Revised: 09/30/2016] [Accepted: 10/05/2016] [Indexed: 01/30/2023]
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