1
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Liu Z, Xu Y, Su H, Jing X, Wang D, Li S, Chen Y, Guan H, Meng L. Chitosan-based hemostatic sponges as new generation hemostatic materials for uncontrolled bleeding emergency: Modification, composition, and applications. Carbohydr Polym 2023; 311:120780. [PMID: 37028883 DOI: 10.1016/j.carbpol.2023.120780] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Revised: 02/12/2023] [Accepted: 02/27/2023] [Indexed: 03/07/2023]
Abstract
The choice of hemostatic technique is a curial concern for surgery and as first-aid treatment in combat. To treat uncontrolled bleeding in complex wound environments, chitosan-based hemostatic sponges have attracted significant attention in recent years because of the excellent biocompatibility, degradability, hemostasis and antibacterial properties of chitosan and their unique sponge-like morphology for high fluid absorption rate and priority aggregation of blood cells/platelets to achieve rapid hemostasis. In this review, we provide a historical perspective on the use of chitosan hemostatic sponges as the new generation of hemostatic materials for uncontrolled bleeding emergencies in complex wounds. We summarize the modification of chitosan, review the current status of preparation protocols of chitosan sponges based on various composite systems, and highlight the recent achievements on the detailed breakdown of the existing chitosan sponges to present the relationship between their composition, physical properties, and hemostatic capacity. Finally, the future opportunities and challenges of chitosan hemostatic sponges are also proposed.
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2
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The physiology and genetics of bacterial responses to antibiotic combinations. Nat Rev Microbiol 2022; 20:478-490. [PMID: 35241807 DOI: 10.1038/s41579-022-00700-5] [Citation(s) in RCA: 45] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/27/2022] [Indexed: 02/08/2023]
Abstract
Several promising strategies based on combining or cycling different antibiotics have been proposed to increase efficacy and counteract resistance evolution, but we still lack a deep understanding of the physiological responses and genetic mechanisms that underlie antibiotic interactions and the clinical applicability of these strategies. In antibiotic-exposed bacteria, the combined effects of physiological stress responses and emerging resistance mutations (occurring at different time scales) generate complex and often unpredictable dynamics. In this Review, we present our current understanding of bacterial cell physiology and genetics of responses to antibiotics. We emphasize recently discovered mechanisms of synergistic and antagonistic drug interactions, hysteresis in temporal interactions between antibiotics that arise from microbial physiology and interactions between antibiotics and resistance mutations that can cause collateral sensitivity or cross-resistance. We discuss possible connections between the different phenomena and indicate relevant research directions. A better and more unified understanding of drug and genetic interactions is likely to advance antibiotic therapy.
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3
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Bekaert M, Goffin N, McMillan S, Desbois AP. Essential Genes of Vibrio anguillarum and Other Vibrio spp. Guide the Development of New Drugs and Vaccines. Front Microbiol 2021; 12:755801. [PMID: 34745063 PMCID: PMC8564382 DOI: 10.3389/fmicb.2021.755801] [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: 08/09/2021] [Accepted: 09/24/2021] [Indexed: 01/04/2023] Open
Abstract
Essential genes in bacterial pathogens are potential drug targets and vaccine candidates because disrupting their function is lethal. The development of new antibiotics, in addition to effective prevention measures such as vaccination, contributes to addressing the global problem of bacterial antibiotic resistance. The aim of this present study was to determine the essential genes of Vibrio anguillarum, a bacterial pathogen of aquatic animals, as a means to identify putative targets for novel drugs and to assist the prioritisation of potential vaccine candidates. Essential genes were characterised by a Tn-seq approach using the TnSC189 mariner transposon to construct a library of 52,662 insertion mutants. In total, 329 essential genes were identified, with 34.7% found within the core genome of this species; each of these genes represents a strong potential drug target. Seven essential gene products were predicted to reside in the cell membrane or be released extracellularly, thus serving as putative vaccine candidates. Comparison to essential gene data from five other studies of Vibrio species revealed 13 proteins to be conserved across the studies, while 25 genes were specific to V. anguillarum and not found to be essential in the other Vibrio spp. This study provides new information on the essential genes of Vibrio species and the methodology may be applied to other pathogens to guide the development of new drugs and vaccines, which will assist efforts to counter antibiotic resistance.
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Affiliation(s)
- Michaël Bekaert
- Institute of Aquaculture, Faculty of Natural Sciences, University of Stirling, Stirling, United Kingdom
| | - Nikki Goffin
- Institute of Aquaculture, Faculty of Natural Sciences, University of Stirling, Stirling, United Kingdom
| | - Stuart McMillan
- Institute of Aquaculture, Faculty of Natural Sciences, University of Stirling, Stirling, United Kingdom
| | - Andrew P Desbois
- Institute of Aquaculture, Faculty of Natural Sciences, University of Stirling, Stirling, United Kingdom
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4
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Wong F, Wilson S, Helbig R, Hegde S, Aftenieva O, Zheng H, Liu C, Pilizota T, Garner EC, Amir A, Renner LD. Understanding Beta-Lactam-Induced Lysis at the Single-Cell Level. Front Microbiol 2021; 12:712007. [PMID: 34421870 PMCID: PMC8372035 DOI: 10.3389/fmicb.2021.712007] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Accepted: 06/30/2021] [Indexed: 12/04/2022] Open
Abstract
Mechanical rupture, or lysis, of the cytoplasmic membrane is a common cell death pathway in bacteria occurring in response to β-lactam antibiotics. A better understanding of the cellular design principles governing the susceptibility and response of individual cells to lysis could indicate methods of potentiating β-lactam antibiotics and clarify relevant aspects of cellular physiology. Here, we take a single-cell approach to bacterial cell lysis to examine three cellular features—turgor pressure, mechanosensitive channels, and cell shape changes—that are expected to modulate lysis. We develop a mechanical model of bacterial cell lysis and experimentally analyze the dynamics of lysis in hundreds of single Escherichia coli cells. We find that turgor pressure is the only factor, of these three cellular features, which robustly modulates lysis. We show that mechanosensitive channels do not modulate lysis due to insufficiently fast solute outflow, and that cell shape changes result in more severe cellular lesions but do not influence the dynamics of lysis. These results inform a single-cell view of bacterial cell lysis and underscore approaches of combatting antibiotic tolerance to β-lactams aimed at targeting cellular turgor.
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Affiliation(s)
- Felix Wong
- Department of Biological Engineering, Institute for Medical Engineering & Science, Massachusetts Institute of Technology, Cambridge, MA, United States.,Infectious Disease and Microbiome Program, Broad Institute of MIT and Harvard, Cambridge, MA, United States.,John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, United States
| | - Sean Wilson
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, United States.,Center for Systems Biology, Harvard University, Cambridge, MA, United States
| | - Ralf Helbig
- Leibniz Institute of Polymer Research and the Max Bergmann Center of Biomaterials, Dresden, Germany
| | - Smitha Hegde
- Centre for Synthetic and Systems Biology, Institute of Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Olha Aftenieva
- Leibniz Institute of Polymer Research and the Max Bergmann Center of Biomaterials, Dresden, Germany
| | - Hai Zheng
- CAS Key Laboratory for Quantitative Engineering Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Chenli Liu
- CAS Key Laboratory for Quantitative Engineering Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Teuta Pilizota
- Centre for Synthetic and Systems Biology, Institute of Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Ethan C Garner
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, United States.,Center for Systems Biology, Harvard University, Cambridge, MA, United States
| | - Ariel Amir
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, United States
| | - Lars D Renner
- Leibniz Institute of Polymer Research and the Max Bergmann Center of Biomaterials, Dresden, Germany
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5
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Memar MY, Yekani M, Celenza G, Poortahmasebi V, Naghili B, Bellio P, Baghi HB. The central role of the SOS DNA repair system in antibiotics resistance: A new target for a new infectious treatment strategy. Life Sci 2020; 262:118562. [PMID: 33038378 DOI: 10.1016/j.lfs.2020.118562] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 09/15/2020] [Accepted: 10/01/2020] [Indexed: 01/19/2023]
Abstract
Bacteria have a considerable ability and potential to acquire resistance against antimicrobial agents by acting diverse mechanisms such as target modification or overexpression, multidrug transporter systems, and acquisition of drug hydrolyzing enzymes. Studying the mechanisms of bacterial cell physiology is mandatory for the development of novel strategies to control the antimicrobial resistance phenomenon, as well as for the control of infections in clinics. The SOS response is a cellular DNA repair mechanism that has an essential role in the bacterial biologic process involved in resistance to antibiotics. The activation of the SOS network increases the resistance and tolerance of bacteria to stress and, as a consequence, to antimicrobial agents. Therefore, SOS can be an applicable target for the discovery of new antimicrobial drugs. In the present review, we focus on the central role of SOS response in bacterial resistance mechanisms and its potential as a new target for control of resistant pathogens.
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Affiliation(s)
- Mohammad Yousef Memar
- Infectious and Tropical Diseases Research Center, Tabriz University of Medical Sciences, Tabriz, Iran; Immunology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran; Students' Research Committee, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Mina Yekani
- Department of Microbiology, Faculty of Medicine, Kashan University of Medical Sciences, Kashan, Iran; Student Research Committee, Kashan University of Medical Sciences, Kashan, Iran
| | - Giuseppe Celenza
- Department of Biotechnological and Applied Clinical Sciences, University of L'Aquila, L'Aquila, Italy.
| | - Vahdat Poortahmasebi
- Infectious and Tropical Diseases Research Center, Tabriz University of Medical Sciences, Tabriz, Iran; Department of Microbiology, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran; Research Center for Clinical Virology, Tehran University of Medical Sciences, Tehran, Iran
| | - Behrooz Naghili
- Infectious and Tropical Diseases Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Pierangelo Bellio
- Department of Biotechnological and Applied Clinical Sciences, University of L'Aquila, L'Aquila, Italy
| | - Hossein Bannazadeh Baghi
- Infectious and Tropical Diseases Research Center, Tabriz University of Medical Sciences, Tabriz, Iran; Immunology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran; Department of Microbiology, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran.
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6
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Kavčič B, Tkačik G, Bollenbach T. Mechanisms of drug interactions between translation-inhibiting antibiotics. Nat Commun 2020; 11:4013. [PMID: 32782250 PMCID: PMC7421507 DOI: 10.1038/s41467-020-17734-z] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Accepted: 07/14/2020] [Indexed: 02/03/2023] Open
Abstract
Antibiotics that interfere with translation, when combined, interact in diverse and difficult-to-predict ways. Here, we explain these interactions by "translation bottlenecks": points in the translation cycle where antibiotics block ribosomal progression. To elucidate the underlying mechanisms of drug interactions between translation inhibitors, we generate translation bottlenecks genetically using inducible control of translation factors that regulate well-defined translation cycle steps. These perturbations accurately mimic antibiotic action and drug interactions, supporting that the interplay of different translation bottlenecks causes these interactions. We further show that growth laws, combined with drug uptake and binding kinetics, enable the direct prediction of a large fraction of observed interactions, yet fail to predict suppression. However, varying two translation bottlenecks simultaneously supports that dense traffic of ribosomes and competition for translation factors account for the previously unexplained suppression. These results highlight the importance of "continuous epistasis" in bacterial physiology.
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Affiliation(s)
- Bor Kavčič
- Institute of Science and Technology Austria, Am Campus 1, A-3400, Klosterneuburg, Austria
| | - Gašper Tkačik
- Institute of Science and Technology Austria, Am Campus 1, A-3400, Klosterneuburg, Austria
| | - Tobias Bollenbach
- Institute for Biological Physics, University of Cologne, Zülpicher Str. 77, D-50937, Cologne, Germany.
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7
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Sharifzadeh S, Brown NW, Shirley JD, Bruce KE, Winkler ME, Carlson EE. Chemical tools for selective activity profiling of bacterial penicillin-binding proteins. Methods Enzymol 2020; 638:27-55. [PMID: 32416917 DOI: 10.1016/bs.mie.2020.02.015] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Penicillin-binding proteins (PBPs) are membrane-associated proteins involved in the biosynthesis of peptidoglycan (PG), the main component of bacterial cell walls. These proteins were discovered and named for their affinity to bind the β-lactam antibiotic penicillin. The importance of the PBPs has long been appreciated; however, specific roles of individual family members in each bacterial strain, as well as their protein-protein interactions, are yet to be understood. The apparent functional redundancy of the 4-18 PBPs that most eubacteria possess makes determination of their individual roles difficult. Existing techniques to study PBPs are not ideal because they do not directly visualize protein activity and can suffer from artifacts and perturbations of native PBP function. Therefore, development of new methods for studying the roles of individual PBPs in cell wall synthesis is required. We recently generated a library of fluorescent chemical probes containing a β-lactone scaffold that specifically targets the PBPs, enabling the visualization of their catalytic activity. Herein, we describe a general protocol to label and detect the activity of individual PBPs in Streptococcus pneumoniae using our fluorescent β-lactone probes.
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Affiliation(s)
- Shabnam Sharifzadeh
- Department of Chemistry, University of Minnesota, Minneapolis, MN, United States
| | - Nathaniel W Brown
- Department of Chemistry, University of Minnesota, Minneapolis, MN, United States
| | - Joshua D Shirley
- Department of Medicinal Chemistry, University of Minnesota, Minneapolis, MN, United States
| | - Kevin E Bruce
- Department of Biology, Indiana University, Bloomington, IN, United States
| | - Malcolm E Winkler
- Department of Biology, Indiana University, Bloomington, IN, United States
| | - Erin E Carlson
- Department of Chemistry, University of Minnesota, Minneapolis, MN, United States; Department of Medicinal Chemistry, University of Minnesota, Minneapolis, MN, United States; Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN, United States.
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8
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Main P, Hata T, Loo TS, Man P, Novak P, Havlíček V, Norris GE, Patchett ML. Bacteriocin ASM1 is an
O
/
S
‐diglycosylated, plasmid‐encoded homologue of glycocin F. FEBS Lett 2020; 594:1196-1206. [DOI: 10.1002/1873-3468.13708] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Revised: 11/20/2019] [Accepted: 11/21/2019] [Indexed: 01/01/2023]
Affiliation(s)
- Patrick Main
- School of Fundamental Sciences Massey University Palmerston North New Zealand
| | - Tomomi Hata
- Department of Food and Nutritional Sciences Ochanomizu University Tokyo Japan
| | - Trevor S. Loo
- School of Fundamental Sciences Massey University Palmerston North New Zealand
| | - Petr Man
- Institute of Microbiology, v.v.i. Academy of Sciences of the Czech Republic Prague 4 Czech Republic
| | - Petr Novak
- Institute of Microbiology, v.v.i. Academy of Sciences of the Czech Republic Prague 4 Czech Republic
| | - Vladimír Havlíček
- Institute of Microbiology, v.v.i. Academy of Sciences of the Czech Republic Prague 4 Czech Republic
| | - Gillian E. Norris
- School of Fundamental Sciences Massey University Palmerston North New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery University of Auckland New Zealand
| | - Mark L. Patchett
- School of Fundamental Sciences Massey University Palmerston North New Zealand
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9
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Meto A, Colombari B, Sala A, Pericolini E, Meto A, Peppoloni S, Blasi E. Antimicrobial and antibiofilm efficacy of a copper/calcium hydroxide-based endodontic paste against Staphylococcus aureus, Pseudomonas aeruginosa and Candida albicans. Dent Mater J 2019; 38:591-603. [PMID: 31257304 DOI: 10.4012/dmj.2018-252] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Endodontic biofilm is a microbial community, enclosed in a polymeric matrix of polysaccharide origin where are found pathogens, like bacteria and opportunistic fungi responsible for various endodontic pathologies. As clinical importance is the fact, that biofilm is extremely resistant to common intracanal irrigants, antimicrobial drugs and host immune responses. The aim of this study was to evaluate the in vitro efficacy of a Cu/CaOH2-based endodontic paste, against bacteria and fungi, such as Staphylococcus aureus, Pseudomonas aeruginosa and Candida albicans. We found that such compound significantly reduced microbial replication time and cell growth. Moreover, biofilm formation and persistence were also affected; treated biofilms showed both a reduced number of cells and levels of released pyoverdine. This study provides the first evidence on effectiveness of this endodontic compound against microbial biofilms. Given its wide range of action, its use in prevention and treatment of the main oral biofilm-associated infections will be discussed.
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Affiliation(s)
- Aida Meto
- School of Doctorate in Clinical and Experimental Medicine, University of Modena and Reggio Emilia
| | - Bruna Colombari
- Department of Surgical, Medical, Dental and Morphological Sciences with interest in Transplant, Oncological and Regenerative Medicine; University of Modena and Reggio Emilia
| | - Arianna Sala
- Department of Surgical, Medical, Dental and Morphological Sciences with interest in Transplant, Oncological and Regenerative Medicine; University of Modena and Reggio Emilia
| | - Eva Pericolini
- Department of Surgical, Medical, Dental and Morphological Sciences with interest in Transplant, Oncological and Regenerative Medicine; University of Modena and Reggio Emilia
| | - Agron Meto
- Department of Therapy, Faculty of Dental Medicine, Aldent University
| | - Samuele Peppoloni
- Department of Surgical, Medical, Dental and Morphological Sciences with interest in Transplant, Oncological and Regenerative Medicine; University of Modena and Reggio Emilia
| | - Elisabetta Blasi
- Department of Surgical, Medical, Dental and Morphological Sciences with interest in Transplant, Oncological and Regenerative Medicine; University of Modena and Reggio Emilia.,School of Specialization in Microbiology and Virology, University of Modena and Reggio Emilia
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10
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Stone MRL, Masi M, Phetsang W, Pagès JM, Cooper MA, Blaskovich MAT. Fluoroquinolone-derived fluorescent probes for studies of bacterial penetration and efflux. MEDCHEMCOMM 2019; 10:901-906. [PMID: 31303987 PMCID: PMC6596217 DOI: 10.1039/c9md00124g] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Accepted: 04/16/2019] [Indexed: 12/21/2022]
Abstract
Fluorescent probes derived from the fluoroquinolone antibiotic ciprofloxacin were synthesised using a Cu(i)-catalysed azide–alkyne cycloaddition (CuAAC) to link a ciprofloxacin azide derivative with alkyne-substituted green and blue fluorophores.
Fluorescent probes derived from the fluoroquinolone antibiotic ciprofloxacin were synthesised using a Cu(i)-catalysed azide–alkyne cycloaddition (CuAAC) to link a ciprofloxacin azide derivative with alkyne-substituted green and blue fluorophores. The azide (2) and fluorophore (3 and 4) derivatives retained antimicrobial activity against Gram-positive and Gram-negative bacteria. The use of confocal fluorescent microscopy showed intracellular penetration, which was substantially enhanced in the presence of carbonyl cyanide 3-chlorophenylhydrazone as an efflux pump inhibitor in Escherichia coli.
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Affiliation(s)
- M Rhia L Stone
- Institute for Molecular Bioscience , The University of Queensland , Brisbane , QLD 4072 , Australia .
| | - Muriel Masi
- Membranes et Cibles Thérapeutiques , UMR_MD1 , Inserm U1261 , Aix-Marseille Univ & IRBA , Facultés de Médecine et de Pharmacie , 27 Bd Jean Moulin , 13005 Marseille , France
| | - Wanida Phetsang
- Institute for Molecular Bioscience , The University of Queensland , Brisbane , QLD 4072 , Australia .
| | - Jean-Marie Pagès
- Membranes et Cibles Thérapeutiques , UMR_MD1 , Inserm U1261 , Aix-Marseille Univ & IRBA , Facultés de Médecine et de Pharmacie , 27 Bd Jean Moulin , 13005 Marseille , France
| | - Matthew A Cooper
- Institute for Molecular Bioscience , The University of Queensland , Brisbane , QLD 4072 , Australia .
| | - Mark A T Blaskovich
- Institute for Molecular Bioscience , The University of Queensland , Brisbane , QLD 4072 , Australia .
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11
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Strong increase in the autofluorescence of cells signals struggle for survival. Sci Rep 2018; 8:12088. [PMID: 30108248 PMCID: PMC6092379 DOI: 10.1038/s41598-018-30623-2] [Citation(s) in RCA: 76] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Accepted: 08/03/2018] [Indexed: 01/13/2023] Open
Abstract
Prokaryotic and eukaryotic cells exhibit an intrinsic natural fluorescence due to the presence of fluorescent cellular structural components and metabolites. Therefore, cellular autofluorescence (AF) is expected to vary with the metabolic states of cells. We examined how exposure to the different stressors changes the AF of Escherichia coli cells. We observed that bactericidal treatments increased green cellular AF, and that de novo protein synthesis was required for the observed AF increase. Excitation and emission spectra and increased expression of the genes from the flavin biosynthesis pathway, strongly suggested that flavins are major contributors to the increased AF. An increased expression of genes encoding diverse flavoproteins which are involved in energy production and ROS detoxification, indicates a cellular strategy to cope with severe stresses. An observed increase in AF under stress is an evolutionary conserved phenomenon as it occurs not only in cells from different bacterial species, but also in yeast and human cells.
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12
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Sharifzadeh S, Boersma MJ, Kocaoglu O, Shokri A, Brown CL, Shirley JD, Winkler ME, Carlson EE. Novel Electrophilic Scaffold for Imaging of Essential Penicillin-Binding Proteins in Streptococcus pneumoniae. ACS Chem Biol 2017; 12:2849-2857. [PMID: 28990753 DOI: 10.1021/acschembio.7b00614] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Peptidoglycan (PG) is a mesh-like heteropolymer made up of glycan chains cross-linked by short peptides and is the major scaffold of eubacterial cell walls, determining cell shape, size, and chaining. This structure, which is required for growth and survival, is located outside of the cytoplasmic membrane of bacterial cells, making it highly accessible to antibiotics. Penicillin-binding proteins (PBPs) are essential for construction of PG and perform transglycosylase activities to generate the glycan strands and transpeptidation to cross-link the appended peptides. The β-lactam antibiotics, which are among the most clinically effective antibiotics for the treatment of bacterial infections, inhibit PBP transpeptidation, ultimately leading to cell lysis. Despite this importance, the discrete functions of individual PBP homologues have been difficult to determine. These major gaps in understanding of PBP activation and macromolecular interactions largely result from a lack of tools to assess the functional state of specific PBPs in bacterial cells. We have identified β-lactones as a privileged scaffold for the generation of PBP-selective probes and utilized these compounds for imaging of the essential proteins, PBP2x and PBP2b, in Streptococcus pneumoniae. We demonstrated that while PBP2b activity is restricted to a ring surrounding the division sites, PBP2x activity is present both at the septal center and at the surrounding ring. These spatially separate regions of PBP2x activity could not be detected by previous activity-based approaches, which highlights a critical strength of our PBP-selective imaging strategy.
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Affiliation(s)
- Shabnam Sharifzadeh
- Departments
of Chemistry, ‡Medicinal Chemistry, and Biochemistry, §Molecular Biology
and Biophysics, University of Minnesota, Minneapolis, Minnesota 55455, United States
- Departments of Biology, ⊥Molecular and Cellular Biochemistry,
and #Chemistry, Indiana University, Bloomington, Indiana 47405, United States
| | - Michael J. Boersma
- Departments
of Chemistry, ‡Medicinal Chemistry, and Biochemistry, §Molecular Biology
and Biophysics, University of Minnesota, Minneapolis, Minnesota 55455, United States
- Departments of Biology, ⊥Molecular and Cellular Biochemistry,
and #Chemistry, Indiana University, Bloomington, Indiana 47405, United States
| | - Ozden Kocaoglu
- Departments
of Chemistry, ‡Medicinal Chemistry, and Biochemistry, §Molecular Biology
and Biophysics, University of Minnesota, Minneapolis, Minnesota 55455, United States
- Departments of Biology, ⊥Molecular and Cellular Biochemistry,
and #Chemistry, Indiana University, Bloomington, Indiana 47405, United States
| | - Alireza Shokri
- Departments
of Chemistry, ‡Medicinal Chemistry, and Biochemistry, §Molecular Biology
and Biophysics, University of Minnesota, Minneapolis, Minnesota 55455, United States
- Departments of Biology, ⊥Molecular and Cellular Biochemistry,
and #Chemistry, Indiana University, Bloomington, Indiana 47405, United States
| | - Clayton L. Brown
- Departments
of Chemistry, ‡Medicinal Chemistry, and Biochemistry, §Molecular Biology
and Biophysics, University of Minnesota, Minneapolis, Minnesota 55455, United States
- Departments of Biology, ⊥Molecular and Cellular Biochemistry,
and #Chemistry, Indiana University, Bloomington, Indiana 47405, United States
| | - Joshua D. Shirley
- Departments
of Chemistry, ‡Medicinal Chemistry, and Biochemistry, §Molecular Biology
and Biophysics, University of Minnesota, Minneapolis, Minnesota 55455, United States
- Departments of Biology, ⊥Molecular and Cellular Biochemistry,
and #Chemistry, Indiana University, Bloomington, Indiana 47405, United States
| | - Malcolm E. Winkler
- Departments
of Chemistry, ‡Medicinal Chemistry, and Biochemistry, §Molecular Biology
and Biophysics, University of Minnesota, Minneapolis, Minnesota 55455, United States
- Departments of Biology, ⊥Molecular and Cellular Biochemistry,
and #Chemistry, Indiana University, Bloomington, Indiana 47405, United States
| | - Erin E. Carlson
- Departments
of Chemistry, ‡Medicinal Chemistry, and Biochemistry, §Molecular Biology
and Biophysics, University of Minnesota, Minneapolis, Minnesota 55455, United States
- Departments of Biology, ⊥Molecular and Cellular Biochemistry,
and #Chemistry, Indiana University, Bloomington, Indiana 47405, United States
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13
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Ortega MA, van der Donk WA. New Insights into the Biosynthetic Logic of Ribosomally Synthesized and Post-translationally Modified Peptide Natural Products. Cell Chem Biol 2016; 23:31-44. [PMID: 26933734 DOI: 10.1016/j.chembiol.2015.11.012] [Citation(s) in RCA: 202] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Revised: 11/10/2015] [Accepted: 11/10/2015] [Indexed: 10/24/2022]
Abstract
Ribosomally synthesized and post-translationally modified peptides (RiPPs) are a large group of structurally diverse natural products. Their biological activities and unique biosynthetic pathways have sparked a growing interest in RiPPs. Furthermore, the relatively low genetic complexity associated with RiPP biosynthesis makes them excellent candidates for synthetic biology applications. This Review highlights recent developments in the understanding of the biosynthesis of several bacterial RiPP family members, the use of the RiPP biosynthetic machinery for generating novel macrocyclic peptides, and the implementation of tools designed to guide the discovery and characterization of novel RiPPs.
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Affiliation(s)
- Manuel A Ortega
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Wilfred A van der Donk
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA; Department of Chemistry, Howard Hughes Medical Institute, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
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14
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The glycocins: in a class of their own. Curr Opin Struct Biol 2016; 40:112-119. [DOI: 10.1016/j.sbi.2016.09.003] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Revised: 09/01/2016] [Accepted: 09/06/2016] [Indexed: 01/28/2023]
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15
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Dremann DN, Chow CS. The development of peptide ligands that target helix 69 rRNA of bacterial ribosomes. Bioorg Med Chem 2016; 24:4486-4491. [PMID: 27492196 PMCID: PMC4992606 DOI: 10.1016/j.bmc.2016.07.050] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Revised: 07/19/2016] [Accepted: 07/22/2016] [Indexed: 12/19/2022]
Abstract
Antibiotic resistance prevents successful treatment of common bacterial infections, making it clear that new target locations and drugs are required to resolve this ongoing challenge. The bacterial ribosome is a common target for antibacterials due to its essential contribution to cell viability. The focus of this work is a region of the ribosome called helix 69 (H69), which was recently identified as a secondary target site for aminoglycoside antibiotics. H69 has key roles in essential ribosomal processes such as subunit association, ribosome recycling, and tRNA selection. Conserved across phylogeny, bacterial H69 also contains two pseudouridines and one 3-methylpseudouridine. Phage display revealed a heptameric peptide sequence that targeted H69. Using solid-phase synthesis, peptide variants with higher affinity and improved selectivity to modified H69 were generated. Electrospray ionization mass spectrometry was used to determine relative apparent dissociation constants of the RNA-peptide complexes.
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Affiliation(s)
| | - Christine S Chow
- Department of Chemistry, Wayne State University, Detroit, MI 48202, USA.
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16
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Czarny TL, Brown ED. A Small-Molecule Screening Platform for the Discovery of Inhibitors of Undecaprenyl Diphosphate Synthase. ACS Infect Dis 2016; 2:489-99. [PMID: 27626101 DOI: 10.1021/acsinfecdis.6b00044] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The bacterial cell wall has long been a celebrated target for antibacterial drug discovery due to its critical nature in bacteria and absence in mammalian systems. At the heart of the cell wall biosynthetic pathway lies undecaprenyl phosphate (Und-P), the lipid-linked carrier upon which the bacterial cell wall is built. This study exploits recent insights into the link between late-stage wall teichoic acid inhibition and Und-P production, in Gram-positive organisms, to develop a cell-based small-molecule screening platform that enriches for inhibitors of undecaprenyl diphosphate synthase (UppS). Screening a chemical collection of 142,000 small molecules resulted in the identification of 6 new inhibitors of UppS. To date, inhibitors of UppS have generally shown off-target effects on membrane potential due to their physical-chemical characteristics. We demonstrate that MAC-0547630, one of the six inhibitors identified, exhibits selective, nanomolar inhibition against UppS without off-target effects on membrane potential. Such characteristics make it a unique chemical probe for exploring the inhibition of UppS in bacterial cell systems.
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Affiliation(s)
- Tomasz L. Czarny
- Department
of Biochemistry and Biomedical Sciences and ‡Michael G. DeGroote Institute of
Infectious Disease Research, McMaster University, Hamilton, Ontario L8N 3Z5, Canada
| | - Eric D. Brown
- Department
of Biochemistry and Biomedical Sciences and ‡Michael G. DeGroote Institute of
Infectious Disease Research, McMaster University, Hamilton, Ontario L8N 3Z5, Canada
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17
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Muciño G, Castro-Obregón S, Hernandez-Pando R, Del Rio G. Autophagy as a target for therapeutic uses of multifunctional peptides. IUBMB Life 2016; 68:259-67. [PMID: 26968336 DOI: 10.1002/iub.1483] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Accepted: 01/17/2016] [Indexed: 12/21/2022]
Abstract
The emergence of complex diseases is promoting a change from one-target to multitarget drugs and peptides are ideal molecules to fulfill this polypharmacologic role. Here we review current status in the design of polypharmacological peptides aimed to treat complex diseases, focusing on tuberculosis. In this sense, combining multiple activities in single molecules is a two-sided sword, as both positive and negative side effects might arise. These polypharmacologic compounds may be directed to regulate autophagy, a catabolic process that enables cells to eliminate intracellular microbes (xenophagy), such as Mycobacterium tuberculosis (MBT). Here we review some strategies to control MBT infection and propose that a peptide combining both antimicrobial and pro-autophagic activities would have a greater potential to limit MBT infection. This endeavor may complement the knowledge gained in understanding the mechanism of action of antibiotics and may lead to the design of better polypharmacological peptides to treat complex diseases such as tuberculosis.
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Affiliation(s)
- Gabriel Muciño
- Department of Neurodevelopment and Physiology, Instituto De Fisiología Celular, UNAM, México, D.F, México
| | - Susana Castro-Obregón
- Department of Neurodevelopment and Physiology, Instituto De Fisiología Celular, UNAM, México, D.F, México
| | - Rogelio Hernandez-Pando
- Experimental Pathology Section, Department of Pathology, National Institute of Medical Sciences and Nutrition "Salvador Zubirán,", Mexico
| | - Gabriel Del Rio
- Department of Biochemistry and Structural Biology, Instituto De Fisiología Celular, UNAM, México, D.F, México
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18
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Stokes JM, Brown ED. Chemical modulators of ribosome biogenesis as biological probes. Nat Chem Biol 2015; 11:924-32. [PMID: 26575239 DOI: 10.1038/nchembio.1957] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2015] [Accepted: 10/13/2015] [Indexed: 01/17/2023]
Abstract
Small-molecule inhibitors of protein biosynthesis have been instrumental in the dissection of the complexities of ribosome structure and function. Ribosome biogenesis, on the other hand, is a complex and largely enigmatic process for which there is a paucity of chemical probes. Indeed, ribosome biogenesis has been studied almost exclusively using genetic and biochemical approaches without the benefit of small-molecule inhibitors of this process. Here, we provide a perspective on the promise of chemical inhibitors of ribosome assembly for future research. We explore key obstacles that complicate the interpretation of studies aimed at perturbing ribosome biogenesis in vivo using genetic methods, and we argue that chemical inhibitors are especially powerful because they can be used to induce perturbations in a manner that obviates these difficulties. Thus, in combination with leading-edge biochemical and structural methods, chemical probes offer unique advantages toward elucidating the molecular events that define the assembly of ribosomes.
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Affiliation(s)
- Jonathan M Stokes
- Michael G. DeGroote Institute for Infectious Disease Research, Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario, Canada
| | - Eric D Brown
- Michael G. DeGroote Institute for Infectious Disease Research, Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario, Canada
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19
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Bollenbach T. Antimicrobial interactions: mechanisms and implications for drug discovery and resistance evolution. Curr Opin Microbiol 2015; 27:1-9. [DOI: 10.1016/j.mib.2015.05.008] [Citation(s) in RCA: 131] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Revised: 05/06/2015] [Accepted: 05/08/2015] [Indexed: 01/06/2023]
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20
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Antagonism screen for inhibitors of bacterial cell wall biogenesis uncovers an inhibitor of undecaprenyl diphosphate synthase. Proc Natl Acad Sci U S A 2015; 112:11048-53. [PMID: 26283394 DOI: 10.1073/pnas.1511751112] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Drug combinations are valuable tools for studying biological systems. Although much attention has been given to synergistic interactions in revealing connections between cellular processes, antagonistic interactions can also have tremendous value in elucidating genetic networks and mechanisms of drug action. Here, we exploit the power of antagonism in a high-throughput screen for molecules that suppress the activity of targocil, an inhibitor of the wall teichoic acid (WTA) flippase in Staphylococcus aureus. Well-characterized antagonism within the WTA biosynthetic pathway indicated that early steps would be sensitive to this screen; however, broader interactions with cell wall biogenesis components suggested that it might capture additional targets. A chemical screening effort using this approach identified clomiphene, a widely used fertility drug, as one such compound. Mechanistic characterization revealed the target was the undecaprenyl diphosphate synthase, an enzyme that catalyzes the synthesis of a polyisoprenoid essential for both peptidoglycan and WTA synthesis. The work sheds light on mechanisms contributing to the observed suppressive interactions of clomiphene and in turn reveals aspects of the biology that underlie cell wall synthesis in S. aureus. Further, this effort highlights the utility of antagonistic interactions both in high-throughput screening and in compound mode of action studies. Importantly, clomiphene represents a lead for antibacterial drug discovery.
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21
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Wang Z, de la Fuente-Núñez C, Shen Y, Haapasalo M, Hancock REW. Treatment of Oral Multispecies Biofilms by an Anti-Biofilm Peptide. PLoS One 2015; 10:e0132512. [PMID: 26168273 PMCID: PMC4500547 DOI: 10.1371/journal.pone.0132512] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Accepted: 06/15/2015] [Indexed: 11/18/2022] Open
Abstract
Human oral biofilms are multispecies microbial communities that exhibit high resistance to antimicrobial agents. Dental plaque gives rise to highly prevalent and costly biofilm-related oral infections, which lead to caries or other types of oral infections. We investigated the ability of the recently identified anti-biofilm peptide 1018 to induce killing of bacterial cells present within oral multispecies biofilms. At 10 μg/ml (6.5 μM), peptide 1018 was able to significantly (p<0.05) prevent biofilm formation over 3 days. The activity of the peptide on preformed biofilms was found to be concentration-dependent since more than 60% of the total plaque biofilm cell population was killed by 10 μg/ml of peptide 1018 in 3 days, while at 5 μg/ml 50% of cells were dead and at 1 μg/ml the peptide triggered cell death in around 30% of the total bacterial population, as revealed by confocal microscopy. The presence of saliva did not affect peptide activity, since no statistically significant difference was found in the ability of peptide 1018 to kill oral biofilms using either saliva coated and non-saliva coated hydroxyapatite surfaces. Scanning electron microscopy experiments indicated that peptide 1018 induced cell lysis in plaque biofilms. Furthermore, combined treatment using peptide 1018 and chlorhexidine (CHX) increased the anti-biofilm activity of each compound compared to when these were used alone, resulting in >50% of the biofilm being killed and >35% being dispersed in only 3 minutes. Peptide 1018 may potentially be used by itself or in combination with CHX as a non-toxic and effective anti-biofilm agent for plaque disinfection in clinical dentistry.
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Affiliation(s)
- Zhejun Wang
- Division of Endodontics, Department of Oral Biological and Medical Sciences, Faculty of Dentistry, University of British Columbia, Vancouver, British Columbia, Canada
- The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) & Key Laboratory of Oral Biomedicine Ministry of Education, School & Hospital of Stomatology, Wuhan University, 237 Luoyu Road, Wuhan, PR China
| | - Cesar de la Fuente-Núñez
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, Vancouver, Canada
| | - Ya Shen
- Division of Endodontics, Department of Oral Biological and Medical Sciences, Faculty of Dentistry, University of British Columbia, Vancouver, British Columbia, Canada
| | - Markus Haapasalo
- Division of Endodontics, Department of Oral Biological and Medical Sciences, Faculty of Dentistry, University of British Columbia, Vancouver, British Columbia, Canada
- * E-mail: (MH); (REWH)
| | - Robert E. W. Hancock
- Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, Vancouver, Canada
- * E-mail: (MH); (REWH)
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22
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Kocaoglu O, Carlson EE. Profiling of β-lactam selectivity for penicillin-binding proteins in Escherichia coli strain DC2. Antimicrob Agents Chemother 2015; 59:2785-90. [PMID: 25733506 PMCID: PMC4394777 DOI: 10.1128/aac.04552-14] [Citation(s) in RCA: 110] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Accepted: 02/24/2015] [Indexed: 02/07/2023] Open
Abstract
Penicillin-binding proteins (PBPs) are integral players in bacterial cell division, and their catalytic activities can be monitored with β-lactam-containing chemical probes. Compounds that target a single PBP could provide important information about the specific role(s) of each enzyme, making identification of such molecules important. We evaluated 22 commercially available β-lactams for inhibition of the PBPs in live Escherichia coli strain DC2. Whole cells were titrated with β-lactam antibiotics and subsequently incubated with a fluorescent penicillin derivative, Bocillin-FL (Boc-FL), to label uninhibited PBPs. Protein visualization was accomplished by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) separation and fluorescent scanning. The examined β-lactams exhibited diverse PBP selectivities, with amdinocillin (mecillinam) showing selectivity for PBP2, aztreonam, piperacillin, cefuroxime, cefotaxime, and ceftriaxone for PBP3, and amoxicillin and cephalexin for PBP4. The remaining β-lactams did not block any PBPs in the DC2 strain of E. coli or inhibited more than one PBP at all examined concentrations in this Gram-negative organism.
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Affiliation(s)
- Ozden Kocaoglu
- Department of Molecular and Cellular Biochemistry, Indiana University Bloomington, Bloomington, Indiana, USA
| | - Erin E Carlson
- Department of Molecular and Cellular Biochemistry, Indiana University Bloomington, Bloomington, Indiana, USA Department of Chemistry, Indiana University Bloomington, Bloomington, Indiana, USA
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23
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Abstract
Drug combinations are increasingly important in disease treatments, for combating drug resistance, and for elucidating fundamental relationships in cell physiology. When drugs are combined, their individual effects on cells may be amplified or weakened. Such drug interactions are crucial for treatment efficacy, but their underlying mechanisms remain largely unknown. To uncover the causes of drug interactions, we developed a systematic approach based on precise quantification of the individual and joint effects of antibiotics on growth of genome-wide Escherichia coli gene deletion strains. We found that drug interactions between antibiotics representing the main modes of action are highly robust to genetic perturbation. This robustness is encapsulated in a general principle of bacterial growth, which enables the quantitative prediction of mutant growth rates under drug combinations. Rare violations of this principle exposed recurring cellular functions controlling drug interactions. In particular, we found that polysaccharide and ATP synthesis control multiple drug interactions with previously unexplained mechanisms, and small molecule adjuvants targeting these functions synthetically reshape drug interactions in predictable ways. These results provide a new conceptual framework for the design of multidrug combinations and suggest that there are universal mechanisms at the heart of most drug interactions.
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24
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Mitosch K, Bollenbach T. Bacterial responses to antibiotics and their combinations. ENVIRONMENTAL MICROBIOLOGY REPORTS 2014; 6:545-557. [PMID: 25756107 DOI: 10.1111/1758-2229.12190] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Antibiotics affect bacterial cell physiology at many levels. Rather than just compensating for the direct cellular defects caused by the drug, bacteria respond to antibiotics by changing their morphology, macromolecular composition, metabolism, gene expression and possibly even their mutation rate. Inevitably, these processes affect each other, resulting in a complex response with changes in the expression of numerous genes. Genome-wide approaches can thus help in gaining a comprehensive understanding of bacterial responses to antibiotics. In addition, a combination of experimental and theoretical approaches is needed for identifying general principles that underlie these responses. Here, we review recent progress in our understanding of bacterial responses to antibiotics and their combinations, focusing on effects at the levels of growth rate and gene expression. We concentrate on studies performed in controlled laboratory conditions, which combine promising experimental techniques with quantitative data analysis and mathematical modeling. While these basic research approaches are not immediately applicable in the clinic, uncovering the principles and mechanisms underlying bacterial responses to antibiotics may, in the long term, contribute to the development of new treatment strategies to cope with and prevent the rise of resistant pathogenic bacteria.
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25
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Bharat A, Brown ED. Phenotypic investigations of the depletion of EngA in Escherichia coli are consistent with a role in ribosome biogenesis. FEMS Microbiol Lett 2014; 353:26-32. [PMID: 24822275 DOI: 10.1111/1574-6968.12403] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
The EngA protein is a conserved and essential bacterial GTPase of largely enigmatic function. While most investigations of EngA have suggested a role in ribosome assembly, the protein has also been implicated in diverse elements of physiology including chromosome segregation, cell division, and cell cycle control. Here, we have probed additional phenotypes related to ribosome biogenesis on depletion of EngA in Escherichia coli to better understand its role in the cell. Depletion of EngA resulted in cold-sensitive growth and stimulation of a ribosomal rRNA promoter, both phenotypes associated with the disruption of ribosome biogenesis in bacteria. Among antibiotics that inhibit translation, depletion of EngA resulted in sensitization to the aminoglycoside class of antibiotics. EngA bound the alarmone ppGpp with equally high affinity as it bound GDP. These data offer additional support for a role in ribosome biogenesis for EngA, possibly in maturation of the A-site of the 50S subunit.
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26
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Cui P, Wu ZX. Selfish punishment with avoiding mechanism can alleviate both first-order and second-order social dilemma. J Theor Biol 2014; 361:111-23. [DOI: 10.1016/j.jtbi.2014.07.021] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Revised: 06/26/2014] [Accepted: 07/19/2014] [Indexed: 10/25/2022]
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27
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Choi JG, Mun SH, Chahar HS, Bharaj P, Kang OH, Kim SG, Shin DW, Kwon DY. Methyl gallate from Galla rhois successfully controls clinical isolates of Salmonella infection in both in vitro and in vivo systems. PLoS One 2014; 9:e102697. [PMID: 25048362 PMCID: PMC4105534 DOI: 10.1371/journal.pone.0102697] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2014] [Accepted: 06/22/2014] [Indexed: 12/03/2022] Open
Abstract
Galla rhois is a commonly used traditional medicine for the treatment of pathogenic bacteria in Korea as well as in other parts of Asia. Methyl gallate (MG), a major component of Galla Rhois, exhibits strong antibacterial activity, but its mechanism of action against Salmonella spp. is unclear. In the present study, we investigated the antibacterial actions of MG against Salmonella. The antibacterial activity determined by broth dilution method indicated that the antibacterial activity of MG against Salmonella strains ranged from 3.9 to 125 µg/ml. In vitro bacterial viability test indicated that MG significantly decreased the viability of Salmonella over 40% when combined with ATPase inhibitors. The time-kill curves showed that a combined MG and ATPase inhibitors (DCCD and NaN3) treatment reduced the bacterial counts dramatically after 24 h. Oral administration of MG showed a strong anti-bacterial activity against WS-5 infected BALB/c mice. In contrast to the untreated Salmonella infected control animals, MG treated groups showed no clinical symptoms of the disease, such as lethargy and liver damage. It was observed that MG treatment significantly increased the survival of animals from Salmonella infection, while in untreated groups all animal succumbed to disease by the sixth day post infection. Thus, the present study demonstrates the therapeutic ability of MG against Salmonella infections.
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Affiliation(s)
- Jang-Gi Choi
- Department of Oriental Pharmacy, College of Pharmacy, Wonkwang University, Wonkwang Oriental Medicines Research Institute, Institute of Biotechnology, Jeonbuk, Korea
- Center of Excellence in Infectious Disease Research, Department of Biomedical Sciences, Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center, El Paso, Texas, United States of America
| | - Su-Hyun Mun
- BK21 Plus Team, Professional Graduate School of Oriental Medicine, Wonkwang University, Iksan, Jeonbuk, Republic of Korea
| | - Harendra S. Chahar
- Center of Excellence in Infectious Disease Research, Department of Biomedical Sciences, Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center, El Paso, Texas, United States of America
| | - Preeti Bharaj
- Center of Excellence in Infectious Disease Research, Department of Biomedical Sciences, Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center, El Paso, Texas, United States of America
| | - Ok-Hwa Kang
- Department of Oriental Pharmacy, College of Pharmacy, Wonkwang University, Wonkwang Oriental Medicines Research Institute, Institute of Biotechnology, Jeonbuk, Korea
| | - Se-Gun Kim
- Department of Oriental Pharmacy, College of Pharmacy, Wonkwang University, Wonkwang Oriental Medicines Research Institute, Institute of Biotechnology, Jeonbuk, Korea
| | - Dong-Won Shin
- Department of Oriental Medicine Resources, Sunchon National University, Jeonnam, Republic of Korea
| | - Dong-Yeul Kwon
- Department of Oriental Pharmacy, College of Pharmacy, Wonkwang University, Wonkwang Oriental Medicines Research Institute, Institute of Biotechnology, Jeonbuk, Korea
- * E-mail:
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28
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Rajendram M, Hurley KA, Foss MH, Thornton KM, Moore JT, Shaw JT, Weibel DB. Gyramides prevent bacterial growth by inhibiting DNA gyrase and altering chromosome topology. ACS Chem Biol 2014; 9:1312-9. [PMID: 24712739 PMCID: PMC4068256 DOI: 10.1021/cb500154m] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
![]()
Antibiotics targeting DNA gyrase
have been a clinical success story
for the past half-century, and the emergence of bacterial resistance
has fueled the search for new gyrase inhibitors. In this paper we
demonstrate that a new class of gyrase inhibitors, the gyramides,
are bacteriostatic agents that competitively inhibit the ATPase activity
of Escherichia coli gyrase and produce supercoiled
DNA in vivo. E. coli cells treated with gyramide
A have abnormally localized, condensed chromosomes that blocks DNA
replication and interrupts chromosome segregation. The resulting alterations
in DNA topology inhibit cell division through a mechanism that involves
the SOS pathway. Importantly, gyramide A is a specific inhibitor of
gyrase and does not inhibit the closely related E. coli enzyme topoisomerase IV. E. coli mutants with reduced
susceptibility to gyramide A do not display cross-resistance to ciprofloxacin
and novobiocin. The results demonstrate that the gyramides prevent
bacterial growth by a mechanism in which the topological state of
chromosomes is altered and halts DNA replication and segregation.
The specificity and activity of the gyramides for inhibiting gyrase
makes these compounds important chemical tools for studying the mechanism
of gyrase and the connection between DNA topology and bacterial cell
division.
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Affiliation(s)
| | | | | | | | - Jared T. Moore
- Department
of Chemistry, University of California-Davis, Davis, California 95616, United States
| | - Jared T. Shaw
- Department
of Chemistry, University of California-Davis, Davis, California 95616, United States
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29
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Sewell EWC, Brown ED. Taking aim at wall teichoic acid synthesis: new biology and new leads for antibiotics. J Antibiot (Tokyo) 2013; 67:43-51. [PMID: 24169797 DOI: 10.1038/ja.2013.100] [Citation(s) in RCA: 83] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2013] [Revised: 09/04/2013] [Accepted: 09/10/2013] [Indexed: 11/09/2022]
Abstract
Wall teichoic acids are a major and integral component of the Gram-positive cell wall. These structures are present across all species of Gram-positive bacteria and constitute roughly half of the cell wall. Despite decades of careful investigation, a definitive physiological function for wall teichoic acids remains elusive. Advances in the genetics and biochemistry of wall teichoic acid synthesis have led to a new understanding of the complexity of cell wall synthesis in Gram-positive bacteria. Indeed, these innovations have provided new molecular tools available to probe the synthesis and function of these cell wall structures. Among recent discoveries are unexpected roles for wall teichoic acid in cell division, coordination of peptidoglycan synthesis and β-lactam resistance in methicillin-resistant Staphylococcus aureus (MRSA). Notably, wall teichoic acid biogenesis has emerged as a bona fide drug target in S. aureus, where remarkable synthetic-viable interactions among biosynthetic genes have been leveraged for the discovery and characterization of novel inhibitors of the pathway.
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Affiliation(s)
- Edward W C Sewell
- Michael G DeGroote Institute for Infectious Disease Research and the Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON, Canada
| | - Eric D Brown
- Michael G DeGroote Institute for Infectious Disease Research and the Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON, Canada
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30
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31
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Peach KC, Bray WM, Winslow D, Linington PF, Linington RG. Mechanism of action-based classification of antibiotics using high-content bacterial image analysis. MOLECULAR BIOSYSTEMS 2013; 9:1837-48. [PMID: 23609915 PMCID: PMC3674180 DOI: 10.1039/c3mb70027e] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Image-based screening has become a mature field over the past decade, largely due to the detailed information that can be obtained about compound mode of action by considering the phenotypic effects of test compounds on cellular morphology. However, very few examples exist of extensions of this approach to bacterial targets. We now report the first high-throughput, high-content platform for the prediction of antibiotic modes of action using image-based screening. This approach employs a unique feature segmentation and extraction protocol to quantify key size and shape metrics of bacterial cells over a range of compound concentrations, and matches the trajectories of these metrics to those of training set compounds of known molecular target to predict the test compound's mode of action. This approach has been used to successfully predict the modes of action of a panel of known antibiotics, and has been extended to the evaluation of natural products libraries for the de novo prediction of compound function directly from primary screening data.
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Affiliation(s)
- Kelly C Peach
- Department of Chemistry and Biochemistry, University of California Santa Cruz, 1156 High Street, Santa Cruz, CA 95064, USA
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32
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Eun YJ, Zhou M, Kiekebusch D, Schlimpert S, Trivedi RR, Bakshi S, Zhong Z, Wahlig TA, Thanbichler M, Weibel DB. Divin: a small molecule inhibitor of bacterial divisome assembly. J Am Chem Soc 2013; 135:9768-76. [PMID: 23738839 DOI: 10.1021/ja404640f] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Bacterial cell division involves the dynamic assembly of division proteins and coordinated constriction of the cell envelope. A wide range of factors regulates cell division--including growth and environmental stresses--and the targeting of the division machinery has been a widely discussed approach for antimicrobial therapies. This paper introduces divin, a small molecule inhibitor of bacterial cell division that may facilitate mechanistic studies of this process. Divin disrupts the assembly of late division proteins, reduces peptidoglycan remodeling at the division site, and blocks compartmentalization of the cytoplasm. In contrast to other division inhibitors, divin does not interact with the tubulin homologue FtsZ, affect chromosome segregation, or activate regulatory mechanisms that inhibit cell division indirectly. Our studies of bacterial cell division using divin as a probe suggest that dividing bacteria proceed through several morphological stages of the cell envelope, and FtsZ is required but not sufficient to compartmentalize the cytoplasmic membrane at the division site. Divin is only moderately toxic to mammalian cells at concentrations that inhibit the growth of clinical pathogens. These characteristics make divin a useful probe for studying bacterial cell division and a starting point for the development of new classes of therapeutic agents.
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Affiliation(s)
- Ye-Jin Eun
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
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33
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Abstract
The need to use front-line antibiotics wisely has never been greater. Antibiotic resistance and multi-drug resistant infection, driven by antibiotic use, remain major public health and professional concerns. To overcome these infection problems, use of older antibiotics active against multi drug-resistant pathogens is increasing - for example, colistin, fosfomycin, pivmecillinam, pristinamycin, temocillin and oral tetracyclines. The number of new antibacterials reaching clinical practice has reduced significantly in the last 20 years, most being focused on therapy of Gram-positive infection - eg linezolid, daptomycin, telavancin and ceftaroline. Recent guidance on antibiotic stewardship in NHS trusts in England is likely to provide a backdrop to antibiotic use in hospitals in the next 5 years.
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34
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Dunbar KL, Mitchell DA. Revealing nature's synthetic potential through the study of ribosomal natural product biosynthesis. ACS Chem Biol 2013; 8:473-87. [PMID: 23286465 DOI: 10.1021/cb3005325] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Ribosomally synthesized posttranslationally modified peptides (RiPPs) are a rapidly growing class of natural products with diverse structures and activities. In recent years, a great deal of progress has been made in elucidating the biosynthesis of various RiPP family members. As with the study of nonribosomal peptide and polyketide biosynthetic enzymes, these investigations have led to the discovery of entirely new biological chemistry. With each unique enzyme investigated, a more complex picture of Nature's synthetic potential is revealed. This Review focuses on recent reports (since 2008) that have changed the way that we think about ribosomal natural product biosynthesis and the enzymology of complex bond-forming reactions.
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Affiliation(s)
- Kyle L. Dunbar
- Department
of Chemistry, ‡Institute for Genomic Biology, and §Department of Microbiology, University
of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United
States
| | - Douglas A. Mitchell
- Department
of Chemistry, ‡Institute for Genomic Biology, and §Department of Microbiology, University
of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United
States
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Barker CA, Allison SE, Zlitni S, Nguyen ND, Das R, Melacini G, Capretta AA, Brown ED. Degradation of MAC13243 and studies of the interaction of resulting thiourea compounds with the lipoprotein targeting chaperone LolA. Bioorg Med Chem Lett 2013; 23:2426-31. [PMID: 23473681 DOI: 10.1016/j.bmcl.2013.02.005] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2012] [Revised: 01/29/2013] [Accepted: 02/01/2013] [Indexed: 11/28/2022]
Abstract
The discovery of novel small molecules that function as antibacterial agents or cellular probes of biology is hindered by our limited understanding of bacterial physiology and our ability to assign mechanism of action. We previously employed a chemical genomic strategy to identify a novel small molecule, MAC13243, as a likely inhibitor of the bacterial lipoprotein targeting chaperone, LolA. Here, we report on the degradation of MAC13243 into the active species, S-(4-chlorobenzyl)isothiourea. Analogs of this compound (e.g., A22) have previously been characterized as inhibitors of the bacterial actin-like protein, MreB. Herein, we demonstrate that the antibacterial activity of MAC13243 and the thiourea compounds are similar; these activities are suppressed or sensitized in response to increases or decreases of LolA copy number, respectively. We provide STD NMR data which confirms a physical interaction between LolA and the thiourea degradation product of MAC13243, with a Kd of ~150 μM. Taken together, we conclude that the thiourea series of compounds share a similar cellular mechanism that includes interaction with LolA in addition to the well-characterized target MreB.
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Affiliation(s)
- Courtney A Barker
- Department of Biochemistry and Biomedical Sciences, McMaster University, 1280 Main Street West, Hamilton, ON, Canada L8S 2K1
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36
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Löppenberg M, Müller H, Pulina C, Oddo A, Teese M, Jose J, Holl R. Synthesis and biological evaluation of flexible and conformationally constrained LpxC inhibitors. Org Biomol Chem 2013; 11:6056-70. [DOI: 10.1039/c3ob41082j] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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37
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Kocaoglu O, Calvo RA, Sham LT, Cozy LM, Lanning BR, Francis S, Winkler ME, Kearns DB, Carlson EE. Selective penicillin-binding protein imaging probes reveal substructure in bacterial cell division. ACS Chem Biol 2012; 7:1746-53. [PMID: 22909777 PMCID: PMC3663142 DOI: 10.1021/cb300329r] [Citation(s) in RCA: 77] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The peptidoglycan cell wall is a common target for antibiotic therapy, but its structure and assembly are only partially understood. Peptidoglycan synthesis requires a suite of penicillin-binding proteins (PBPs), the individual roles of which are difficult to determine because each enzyme is often dispensable for growth perhaps due to functional redundancy. To address this challenge, we sought to generate tools that would enable selective examination of a subset of PBPs. We designed and synthesized fluorescent and biotin derivatives of the β-lactam-containing antibiotic cephalosporin C. These probes facilitated specific in vivo labeling of active PBPs in both Bacillus subtilis PY79 and an unencapsulated derivative of D39 Streptococcus pneumoniae. Microscopy and gel-based analysis indicated that the cephalosporin C-based probes are more selective than BOCILLIN-FL, a commercially available penicillin V analogue, which labels all PBPs. Dual labeling of live cells performed by saturation of cephalosporin C-susceptible PBPs followed by tagging of the remaining PBP population with BOCILLIN-FL demonstrated that the two sets of PBPs are not co-localized. This suggests that even PBPs that are located at a particular site (e.g., septum) are not all intermixed, but rather that PBP subpopulations are discretely localized. Accordingly, the Ceph C probes represent new tools to explore a subset of PBPs and have the potential to facilitate a deeper understand of the roles of this critical class of proteins.
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Affiliation(s)
- Ozden Kocaoglu
- Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN 47405, USA
| | - Rebecca A. Calvo
- Department of Biology, Indiana University, Bloomington, IN 47405, USA
| | - Lok-To Sham
- Department of Biology, Indiana University, Bloomington, IN 47405, USA
| | - Loralyn M. Cozy
- Department of Biology, Indiana University, Bloomington, IN 47405, USA
| | - Bryan R. Lanning
- Department of Chemistry, Indiana University, Bloomington, IN 47405, USA
| | - Samson Francis
- Department of Chemistry, Indiana University, Bloomington, IN 47405, USA
| | | | - Daniel B. Kearns
- Department of Biology, Indiana University, Bloomington, IN 47405, USA
| | - Erin E. Carlson
- Department of Chemistry, Indiana University, Bloomington, IN 47405, USA
- Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN 47405, USA
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38
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Eun YJ, Foss MH, Kiekebusch D, Pauw DA, Westler WM, Thanbichler M, Weibel DB. DCAP: a broad-spectrum antibiotic that targets the cytoplasmic membrane of bacteria. J Am Chem Soc 2012; 134:11322-5. [PMID: 22741745 DOI: 10.1021/ja302542j] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Persistent infections are frequently caused by dormant and biofilm-associated bacteria, which often display characteristically slow growth. Antibiotics that require rapid cell growth may be ineffective against these organisms and thus fail to prevent reoccurring infections. In contrast to growth-based antimicrobial agents, membrane-targeting drugs effectively kill slow-growing bacteria. Herein we introduce 2-((3-(3,6-dichloro-9H-carbazol-9-yl)-2-hydroxypropyl)amino)-2-(hydroxymethyl)propane-1,3-diol (DCAP), a potent broad-spectrum antibiotic that reduces the transmembrane potential of Gram-positive and Gram-negative bacteria and causes mislocalization of essential membrane-associated proteins, including MinD and FtsA. Importantly, DCAP kills nutrient-deprived microbes and sterilizes bacterial biofilms. DCAP is lethal against bacterial cells, has no effect on red blood cell membranes, and only decreases the viability of mammalian cells after ≥6 h. We conclude that membrane-active compounds are a promising solution for treating persistent infections. DCAP expands the limited number of compounds in this class of therapeutic small molecules and provides new opportunities for the development of potent broad-spectrum antimicrobial agents.
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Affiliation(s)
- Ye-Jin Eun
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
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39
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Boudreau MA, Fisher JF, Mobashery S. Messenger functions of the bacterial cell wall-derived muropeptides. Biochemistry 2012; 51:2974-90. [PMID: 22409164 DOI: 10.1021/bi300174x] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Bacterial muropeptides are soluble peptidoglycan structures central to recycling of the bacterial cell wall and messengers in diverse cell signaling events. Bacteria sense muropeptides as signals that antibiotics targeting cell-wall biosynthesis are present, and eukaryotes detect muropeptides during the innate immune response to bacterial infection. This review summarizes the roles of bacterial muropeptides as messengers, with a special emphasis on bacterial muropeptide structures and the relationship of structure to the biochemical events that the muropeptides elicit. Muropeptide sensing and recycling in both Gram-positive and Gram-negative bacteria are discussed, followed by muropeptide sensing by eukaryotes as a crucial event in the innate immune response of insects (via peptidoglycan-recognition proteins) and mammals (through Nod-like receptors) to bacterial invasion.
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Affiliation(s)
- Marc A Boudreau
- Department of Chemistry and Biochemistry, Nieuwland Science Hall, University of Notre Dame, Notre Dame, Indiana 46556, USA
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40
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Edlund A, Ek K, Breitholtz M, Gorokhova E. Antibiotic-induced change of bacterial communities associated with the copepod Nitocra spinipes. PLoS One 2012; 7:e33107. [PMID: 22427962 PMCID: PMC3299745 DOI: 10.1371/journal.pone.0033107] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2011] [Accepted: 02/03/2012] [Indexed: 01/01/2023] Open
Abstract
Environmental pressures, such as physical factors, diet and contaminants may affect interactions between microbial symbionts and their multicellular hosts. Despite obvious relevance, effects of antimicrobial contaminants on host-symbiont relations in non-target aquatic organisms are largely unknown. We show that exposure to antibiotics had negative effects on survival and juvenile development of the copepod Nitocra spinipes and caused significant alterations in copepod-associated bacterial communities. The significant positive correlations between indices of copepod development and bacterial diversity indicate that disruption of the microflora was likely to be an important factor behind retarded juvenile development in the experimental animals. Moreover, as evidenced by ribotype distribution in the bacterial clone libraries, the exposure to antibiotics caused a shift in dominance from Betaproteobacteria to Cardinium bacteria; the latter have been shown to cause reproductive manipulations in various terrestrial arthropods. Thus, in addition to providing evidence that the antibiotic-induced perturbation of the microbial community associates with reductions in fitness-related traits of the host, this study is the first record of a copepod serving as a host for endosymbiotic Cardinium. Taken together, our results suggest that (1) antimicrobial substances and possibly other stressors can affect micobiome and symbiont-mediated interactions in copepods and other hosts, and (2) Cardinium endosymbionts may occur in other copepods and affect reproduction of their hosts.
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Affiliation(s)
- Anna Edlund
- Department of Systems Ecology, Stockholm University, Stockholm, Sweden
| | - Karin Ek
- Department of Applied Environmental Science, Stockholm University, Stockholm, Sweden
| | - Magnus Breitholtz
- Department of Applied Environmental Science, Stockholm University, Stockholm, Sweden
| | - Elena Gorokhova
- Department of Applied Environmental Science, Stockholm University, Stockholm, Sweden
- * E-mail:
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41
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Abstract
Enzymes are often excellent drug targets. Yet drug pressure on an enzyme target often fosters the rise of cells with resistance-conferring mutations, some of which may compromise fitness and others that compensate to restore fitness. This review presents, first, a structural analysis of a diverse group of wild-type and mutant enzyme targets and, second, an in-depth analysis of five diverse targets to elucidate a broader perspective of the effects of resistance-conferring mutations on protein or organismal fitness. The structural analysis reveals that resistance-conferring mutations may introduce steric hindrance or eliminate critical interactions, as expected, but that they may also have indirect effects such as altering protein dynamics and enzyme kinetics. The structure-based development of the latest generation of inhibitors targeting HIV reverse transcriptase, P. falciparum and S. aureus dihydrofolate reductase, neuraminidase, and epithelial growth factor receptor (EGFR) tyrosine kinase, is highlighted to emphasize lessons that may be applied to future drug discovery to overcome mutation-induced resistance. Successful next-generation drugs tend to be more flexible and exploit a greater number of interactions mimicking those of the substrate with conserved residues.
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Affiliation(s)
- Amy C Anderson
- Department of Pharmaceutical Sciences, University of Connecticut, Storrs, Connecticut 06269, United States.
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42
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McCusker KP, Fujimori DG. The chemistry of peptidyltransferase center-targeted antibiotics: enzymatic resistance and approaches to countering resistance. ACS Chem Biol 2012; 7:64-72. [PMID: 22208312 DOI: 10.1021/cb200418f] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The continued ability to treat bacterial infections requires effective antibiotics. The development of new therapeutics is guided by knowledge of the mechanisms of action of and resistance to these antibiotics. Continued efforts to understand and counteract antibiotic resistance mechanisms at a molecular level have the potential to direct development of new therapeutic strategies in addition to providing insight into the underlying biochemical functions impacted by antibiotics. The interaction of antibiotics with the peptidyltransferase center and adjacent exit tunnel within the bacterial ribosome is the predominant mechanism by which antibiotics impede translation, thus stalling growth. Resistance enzymes catalyze the chemical modification of the RNA that composes these functional regions, leading to diminished binding of antibiotics. This review discusses recent advances in the elucidation of chemical mechanisms underlying resistance and driving the development of new antibiotics.
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Affiliation(s)
- Kevin P. McCusker
- Department of Cellular and Molecular Pharmacology and ‡Department of Pharmaceutical Chemistry, University of California, San Francisco, 600 16th St, MC2280, San Francisco, California 94158, United States
| | - Danica Galonić Fujimori
- Department of Cellular and Molecular Pharmacology and ‡Department of Pharmaceutical Chemistry, University of California, San Francisco, 600 16th St, MC2280, San Francisco, California 94158, United States
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Fjell CD, Hiss JA, Hancock REW, Schneider G. Designing antimicrobial peptides: form follows function. Nat Rev Drug Discov 2011; 11:37-51. [PMID: 22173434 DOI: 10.1038/nrd3591] [Citation(s) in RCA: 1350] [Impact Index Per Article: 103.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Multidrug-resistant bacteria are a severe threat to public health. Conventional antibiotics are becoming increasingly ineffective as a result of resistance, and it is imperative to find new antibacterial strategies. Natural antimicrobials, known as host defence peptides or antimicrobial peptides, defend host organisms against microbes but most have modest direct antibiotic activity. Enhanced variants have been developed using straightforward design and optimization strategies and are being tested clinically. Here, we describe advanced computer-assisted design strategies that address the difficult problem of relating primary sequence to peptide structure, and are delivering more potent, cost-effective, broad-spectrum peptides as potential next-generation antibiotics.
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Affiliation(s)
- Christopher D Fjell
- Centre for Microbial Diseases and Immunity Research, University of British Columbia, 2259 Lower Mall, Vancouver, British Columbia V6T 1Z4, Canada
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