101
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Alikhani M, Hakimi M, Moeini K, Mashreghi M, Eigner V, Dusek M. Spectral, structural, biological and molecular docking studies of a new mixed-valence V(IV)/V(V) ofloxacin complex. J Mol Struct 2020. [DOI: 10.1016/j.molstruc.2020.128300] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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102
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Anchoring BODIPY photosensitizers enable pan-microbial photoinactivation. Eur J Med Chem 2020; 199:112361. [PMID: 32408214 DOI: 10.1016/j.ejmech.2020.112361] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Revised: 04/17/2020] [Accepted: 04/17/2020] [Indexed: 12/20/2022]
Abstract
Photodynamic antimicrobial chemotherapy (PACT) is an effective strategy to inactivate pathogenic and resistant microbes. However, pan-microbial photoinactivation has hardly achieved. In this manuscript, we built anti-microbial PSs based on 2,6-diiodo-1,3,5,7-tetramethyl BODIPY (2I-BDP) using anchoring strategy through modifications on boron atom with bis-cationic moieties. With appropriate bis-cationic anchoring, we could achieve effective PACT for pan-microbial photoinactivation via straight forward modifications. Our studies suggested that integration of an efficient photosensitizer, good amphiphilicity, as well as tight interaction with microbial membrane could be essential for effective PACT.
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103
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Cao P, Wall D. The Fluidity of the Bacterial Outer Membrane Is Species Specific: Bacterial Lifestyles and the Emergence of a Fluid Outer Membrane. Bioessays 2020; 42:e1900246. [PMID: 32363627 PMCID: PMC7392792 DOI: 10.1002/bies.201900246] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Revised: 03/23/2020] [Indexed: 01/17/2023]
Abstract
The outer membrane (OM) is an essential barrier that guards Gram-negative bacteria from diverse environmental insults. Besides functioning as a chemical gatekeeper, the OM also contributes towards the strength and stiffness of cells and allows them to sustain mechanical stress. Largely influenced by studies of Escherichia coli, the OM is viewed as a rigid barrier where OM proteins and lipopolysaccharides display restricted mobility. Here the discussion is extended to other bacterial species, with a focus on Myxococcus xanthus. In contrast to the rigid OM paradigm, myxobacteria possess a relatively fluid OM. It is concluded that the fluidity of the OM varies across environmental species, which is likely linked to their evolution and adaptation to specific ecological niches. Importantly, a fluid OM can endow bacteria with distinct functions for cell-cell and cell-environment interactions.
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Affiliation(s)
| | - Daniel Wall
- Department of Molecular Biology, University of Wyoming, 1000 E University Avenue, Laramie, WY, 82071, USA
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104
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Del Valle A, Torra J, Bondia P, Tone CM, Pedraz P, Vadillo-Rodriguez V, Flors C. Mechanically Induced Bacterial Death Imaged in Real Time: A Simultaneous Nanoindentation and Fluorescence Microscopy Study. ACS APPLIED MATERIALS & INTERFACES 2020; 12:31235-31241. [PMID: 32476402 DOI: 10.1021/acsami.0c08184] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Mechano-bactericidal nanomaterials rely on their mechanical or physical interactions with bacteria and are promising antimicrobial strategies that overcome bacterial resistance. However, the real effect of mechanical versus chemical action on their activity is under debate. In this paper, we quantify the forces necessary to produce critical damage to the bacterial cell wall by performing simultaneous nanoindentation and fluorescence imaging of single bacterial cells. Our experimental setup allows puncturing the cell wall of an immobilized bacterium with the tip of an atomic force microscope (AFM) and following in real time the increase in the fluorescence signal from a cell membrane integrity marker. We correlate the forces exerted by the AFM tip with the fluorescence dynamics for tens of cells, and we find that forces above 20 nN are necessary to exert critical damage. Moreover, a similar experiment is performed in which bacterial viability is assessed through physiological activity, in order to gain a more complete view of the effect of mechanical forces on bacteria. Our results contribute to the quantitative understanding of the interaction between bacteria and nanomaterials.
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Affiliation(s)
- Adrián Del Valle
- Madrid Institute for Advanced Studies in Nanoscience (IMDEA Nanociencia), C/Faraday 9, Madrid 28049, Spain
| | - Joaquim Torra
- Madrid Institute for Advanced Studies in Nanoscience (IMDEA Nanociencia), C/Faraday 9, Madrid 28049, Spain
| | - Patricia Bondia
- Madrid Institute for Advanced Studies in Nanoscience (IMDEA Nanociencia), C/Faraday 9, Madrid 28049, Spain
| | - Caterina M Tone
- Madrid Institute for Advanced Studies in Nanoscience (IMDEA Nanociencia), C/Faraday 9, Madrid 28049, Spain
| | - Patricia Pedraz
- Madrid Institute for Advanced Studies in Nanoscience (IMDEA Nanociencia), C/Faraday 9, Madrid 28049, Spain
| | | | - Cristina Flors
- Madrid Institute for Advanced Studies in Nanoscience (IMDEA Nanociencia), C/Faraday 9, Madrid 28049, Spain
- Nanobiotechnology Unit Associated to the National Center for Biotechnology (CNB-CSIC-IMDEA), Madrid 28049, Spain
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105
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Abstract
The last universal cellular ancestor (LUCA) is the most recent population of organisms from which all cellular life on Earth descends. The reconstruction of the genome and phenotype of the LUCA is a major challenge in evolutionary biology. Given that all life forms are associated with viruses and/or other mobile genetic elements, there is no doubt that the LUCA was a host to viruses. Here, by projecting back in time using the extant distribution of viruses across the two primary domains of life, bacteria and archaea, and tracing the evolutionary histories of some key virus genes, we attempt a reconstruction of the LUCA virome. Even a conservative version of this reconstruction suggests a remarkably complex virome that already included the main groups of extant viruses of bacteria and archaea. We further present evidence of extensive virus evolution antedating the LUCA. The presence of a highly complex virome implies the substantial genomic and pan-genomic complexity of the LUCA itself.
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106
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Gordesli-Duatepe FP, Park BJ, Kawas LH, Abu-Lail NI. Atomic Force Microscopy Investigation of the Contributions of Listeria monocytogenes Cell-Wall Biomacromolecules to Their Adherence and Mechanics. J Phys Chem B 2020; 124:5872-5883. [PMID: 32544332 DOI: 10.1021/acs.jpcb.0c04025] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In this work, the contributions of the pathogenic Listeria monocytogenes cell-wall biomacromolecules to the bacterial mechanics and adhesion to a model inert surface of silicon nitride in water were investigated by atomic force microscopy. Chemical ethylenediaminetetraacetic acid (EDTA) and biological enzymatic trypsin treatments of cells were performed to partially or totally remove the bacterial cell-wall proteins and carbohydrates. Removal of 48.2% proteins and 29.2% of carbohydrates from the cell-wall of the bacterium by the EDTA treatment resulted in a significant decrease in the length of the bacterial cell-wall biomacromolecules and an increase in the rigidity of the bacterial cells as predicted from fitting a model of steric repulsion to the force-distance approach data and classic Hertz model to the indentation-force data, respectively. In comparison, removal of almost all the cell-wall proteins (99.5% removal) and 8.6% of cell-wall carbohydrates by the trypsin treatment resulted in an increase in the elasticity of the bacterial cells, an increase in the extension of the cell-wall biomacromolecules, and a significant decrease in their apparent grafting densities. In addition, adhesion strength of native-untreated L. monocytogenes to silicon nitride in water decreased by 30% on average after the EDTA treatment and further decreased by 60% on average after the trypsin treatment, showing a positive correlation with the% removal of cell-wall proteins by the EDTA and trypsin treatments, respectively.
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Affiliation(s)
- F Pinar Gordesli-Duatepe
- Department of Genetics and Bioengineering, Faculty of Engineering, Izmir University of Economics, 35330 Izmir, Turkey
| | - Bong J Park
- The Gene and Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, Washington 99164, United States
| | - Leen H Kawas
- Department of Veterinary and Comparative Anatomy, Pharmacology, and Physiology, Washington State University Pullman, Washington 99164-6520, United States
| | - Nehal I Abu-Lail
- Department of Biomedical Engineering and Chemical Engineering, The University of Texas at San Antonio, San Antonio, Texas 78249, United States
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107
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Antimicrobial Activity and Metabolite Analysis of Ganoderma boninense Fruiting Body. JOURNAL OF PURE AND APPLIED MICROBIOLOGY 2020. [DOI: 10.22207/jpam.14.2.16] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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108
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Harper CE, Hernandez CJ. Cell biomechanics and mechanobiology in bacteria: Challenges and opportunities. APL Bioeng 2020; 4:021501. [PMID: 32266323 PMCID: PMC7113033 DOI: 10.1063/1.5135585] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Accepted: 02/27/2020] [Indexed: 12/11/2022] Open
Abstract
Physical forces play a profound role in the survival and function of all known forms of life. Advances in cell biomechanics and mechanobiology have provided key insights into the physiology of eukaryotic organisms, but much less is known about the roles of physical forces in bacterial physiology. This review is an introduction to bacterial mechanics intended for persons familiar with cells and biomechanics in mammalian cells. Bacteria play a major role in human health, either as pathogens or as beneficial commensal organisms within the microbiome. Although bacteria have long been known to be sensitive to their mechanical environment, understanding the effects of physical forces on bacterial physiology has been limited by their small size (∼1 μm). However, advancements in micro- and nano-scale technologies over the past few years have increasingly made it possible to rigorously examine the mechanical stress and strain within individual bacteria. Here, we review the methods currently used to examine bacteria from a mechanical perspective, including the subcellular structures in bacteria and how they differ from those in mammalian cells, as well as micro- and nanomechanical approaches to studying bacteria, and studies showing the effects of physical forces on bacterial physiology. Recent findings indicate a large range in mechanical properties of bacteria and show that physical forces can have a profound effect on bacterial survival, growth, biofilm formation, and resistance to toxins and antibiotics. Advances in the field of bacterial biomechanics have the potential to lead to novel antibacterial strategies, biotechnology approaches, and applications in synthetic biology.
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Affiliation(s)
- Christine E. Harper
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, New York 14853, USA
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109
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Mathelié-Guinlet M, Asmar AT, Collet JF, Dufrêne YF. Bacterial Cell Mechanics Beyond Peptidoglycan. Trends Microbiol 2020; 28:706-708. [PMID: 32466989 DOI: 10.1016/j.tim.2020.04.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Revised: 04/20/2020] [Accepted: 04/21/2020] [Indexed: 11/29/2022]
Abstract
The bacterial cell envelope plays essential roles in controlling cell shape, division, pathogenicity, and resistance against external stresses. In Escherichia coli, peptidoglycan (PG) has long been thought to be the primary component that conveys mechanical strength to the envelope. But a recent publication demonstrates the key contribution of the lipoprotein Lpp in defining the stiffness of the cell envelope and its sensitivity to drugs.
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Affiliation(s)
- Marion Mathelié-Guinlet
- Institute of Life Sciences, UCLouvain, Croix du Sud, 4-5, bte L7.07.07, B-1348 Louvain-la-Neuve, Belgium
| | | | - Jean-François Collet
- de Duve Institute, UCLouvain, Brussels, Belgium; Walloon Excellence in Life sciences and Biotechnology (WELBIO), Wavre, Belgium.
| | - Yves F Dufrêne
- Institute of Life Sciences, UCLouvain, Croix du Sud, 4-5, bte L7.07.07, B-1348 Louvain-la-Neuve, Belgium; Walloon Excellence in Life sciences and Biotechnology (WELBIO), Wavre, Belgium.
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110
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Li X, Bosch-Tijhof CJ, Wei X, de Soet JJ, Crielaard W, Loveren CV, Deng DM. Efficiency of chemical versus mechanical disruption methods of DNA extraction for the identification of oral Gram-positive and Gram-negative bacteria. J Int Med Res 2020; 48:300060520925594. [PMID: 32459112 PMCID: PMC7278108 DOI: 10.1177/0300060520925594] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Objective Clinical diagnostics often requires the detection of multiple bacterial
species in limited clinical samples with a single DNA extraction method.
This study aimed to compare the bacterial DNA extraction efficiency of two
lysis methods automated with the MagNA-Pure LC instrument. The samples
included five oral bacterial species (three Gram-positive and two
Gram-negative) with or without human saliva background. Methods Genomic DNA (gDNA) was extracted from bacterial cultures by bead-beating
lysis (BMP) or chemical lysis (MP), followed by automated purification and
measurement by quantitative PCR. Results For pure bacterial cultures, the MP method yielded higher quantities of
extracted DNA and a lower detection limit than the BMP method, except where
the samples contained high numbers of Gram-positive bacteria. For bacterial
cultures with a saliva background, no difference in gDNA extraction efficacy
was observed between the two methods. Conclusions The efficiency of a bacterial DNA extraction method is not only affected by
the bacterial cell wall structure but also by the sample milieu. The MP
method provided superior gDNA extraction efficiency when the samples
contained a single bacterial species, whereas either of the BMP and MP
methods could be applied with similar efficiencies to samples containing
multiple species of bacteria.
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Affiliation(s)
- Xiaolan Li
- Department of Operative Dentistry and Endodontics, Guanghua School of Stomatology & Hospital of Stomatology, Guangdong Province Key Laboratory of Stomatology, Sun Yat-sen University, Guangzhou, Guangdong, China.,Department of Preventive Dentistry, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Caroline J Bosch-Tijhof
- Department of Preventive Dentistry, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Xi Wei
- Department of Operative Dentistry and Endodontics, Guanghua School of Stomatology & Hospital of Stomatology, Guangdong Province Key Laboratory of Stomatology, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Johannes J de Soet
- Department of Preventive Dentistry, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Wim Crielaard
- Department of Preventive Dentistry, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Cor van Loveren
- Department of Preventive Dentistry, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Dong Mei Deng
- Department of Preventive Dentistry, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
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111
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Abstract
The FtsZ protein is a highly conserved bacterial tubulin homolog. In vivo, the functional form of FtsZ is the polymeric, ring-like structure (Z-ring) assembled at the future division site during cell division. While it is clear that the Z-ring plays an essential role in orchestrating cytokinesis, precisely what its functions are and how these functions are achieved remain elusive. In this article, we review what we have learned during the past decade about the Z-ring's structure, function, and dynamics, with a particular focus on insights generated by recent high-resolution imaging and single-molecule analyses. We suggest that the major function of the Z-ring is to govern nascent cell pole morphogenesis by directing the spatiotemporal distribution of septal cell wall remodeling enzymes through the Z-ring's GTP hydrolysis-dependent treadmilling dynamics. In this role, FtsZ functions in cell division as the counterpart of the cell shape-determining actin homolog MreB in cell elongation.
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Affiliation(s)
- Ryan McQuillen
- Department of Biophysics & Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA; ,
| | - Jie Xiao
- Department of Biophysics & Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA; ,
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112
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d-Methionine and d-Phenylalanine Improve Lactococcus lactis F44 Acid Resistance and Nisin Yield by Governing Cell Wall Remodeling. Appl Environ Microbiol 2020; 86:AEM.02981-19. [PMID: 32111594 DOI: 10.1128/aem.02981-19] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2019] [Accepted: 02/22/2020] [Indexed: 12/30/2022] Open
Abstract
Lactococcus lactis encounters various environmental challenges, especially acid stress, during its growth. The cell wall can maintain the integrity and shape of the cell under environmental stress, and d-amino acids play an important role in cell wall synthesis. Here, by analyzing the effects of 19 different d-amino acids on the physiology of L. lactis F44, we found that exogenously supplied d-methionine and d-phenylalanine increased the nisin yield by 93.22% and 101.29%, respectively, as well as significantly increasing the acid resistance of L. lactis F44. The composition of the cell wall in L. lactis F44 with exogenously supplied d-Met or d-Phe was further investigated via a vancomycin fluorescence experiment and a liquid chromatography-mass spectrometry assay, which demonstrated that d-Met could be incorporated into the fifth position of peptidoglycan (PG) muropeptides and d-Phe could be added to the fourth and fifth positions. Moreover, overexpression of the PG synthesis gene murF further enhanced the levels of d-Met and d-Phe involved in PG and increased the survival rate under acid stress and the nisin yield of the strain. This study reveals that the exogenous supply of d-Met or d-Phe can change the composition of the cell wall and influence acid tolerance as well as nisin yield in L. lactis IMPORTANCE As d-amino acids play an important role in cell wall synthesis, we analyzed the effects of 19 different d-amino acids on L. lactis F44, demonstrating that d-Met and d-Phe can participate in peptidoglycan (PG) synthesis and improve the acid resistance and nisin yield of this strain. murF overexpression further increased the levels of d-Met and d-Phe incorporated into PG and contributed to the acid resistance of the strain. These findings suggest that d-Met and d-Phe can be incorporated into PG to improve the acid resistance and nisin yield of L. lactis, and this study provides new ideas for the enhancement of nisin production.
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113
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Lipoprotein Lpp regulates the mechanical properties of the E. coli cell envelope. Nat Commun 2020; 11:1789. [PMID: 32286264 PMCID: PMC7156740 DOI: 10.1038/s41467-020-15489-1] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2019] [Accepted: 03/09/2020] [Indexed: 12/16/2022] Open
Abstract
The mechanical properties of the cell envelope in Gram-negative bacteria are controlled by the peptidoglycan, the outer membrane, and the proteins interacting with both layers. In Escherichia coli, the lipoprotein Lpp provides the only covalent crosslink between the outer membrane and the peptidoglycan. Here, we use single-cell atomic force microscopy and genetically engineered strains to study the contribution of Lpp to cell envelope mechanics. We show that Lpp contributes to cell envelope stiffness in two ways: by covalently connecting the outer membrane to the peptidoglycan, and by controlling the width of the periplasmic space. Furthermore, mutations affecting Lpp function substantially increase bacterial susceptibility to the antibiotic vancomycin, indicating that Lpp-dependent effects can affect antibacterial drug efficacy. Lipoprotein Lpp provides a covalent crosslink between the outer membrane and the peptidoglycan in E. coli. Here, the authors use atomic force microscopy to show that Lpp contributes to cell envelope stiffness by covalently connecting the two layers and by controlling the width of the periplasmic space.
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114
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Bao Q, Hosoe A, Hosomi M, Terada A. Quorum quenching acylase impacts the viability and morphological change of Agrobacterium tumefaciens cells. J Biosci Bioeng 2020; 130:82-88. [PMID: 32280054 DOI: 10.1016/j.jbiosc.2020.02.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 02/05/2020] [Accepted: 02/06/2020] [Indexed: 11/17/2022]
Abstract
Acylase is known as a quorum quenching enzyme that degrades N-acyl-homoserine lactones (AHLs), a key signaling molecule in a quorum sensing (QS) mechanism. Acylase I cleaves the acyl-chain in the chemical structures of AHLs, thereby exerting an anti-biofilm effect by the inhibition of bacterial cell-cell communication and resultant secretion of extracellular polymeric substances (EPS). However, the physical and physiological impacts of acylase on bacterial cells remain to be systematically elucidated. This study, therefore, investigated the effect of active and inactive acylase addition on the growth, viability, and cell morphologies of Agrobacterium tumefaciens. For comparison, active and inactive lysozymes were taken as positive controls. The results showed that active acylase inhibited A. tumefaciens cell growth at concentrations ranging from 0.1 to 1000 μg mL-1, and so did active lysozyme. Fluorescent detection by Live/Dead staining underpinned that cell viability of A. tumefaciens decreased at concentrations higher than 0.1 μg mL-1 for both acylase and lysozyme, although lysozyme inflicted higher degree of cellular damage. Moreover, atomic force microscopy unraveled a noticeable distortion of A. tumefaciens cells by both acylase and lysozyme. Together, the results showed that acylase not only blocked AHLs-based QS mechanisms but also compromised cell viability and altered surface morphology of A. tumefaciens cells, as observed by the addition of hydrolase.
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Affiliation(s)
- Qian Bao
- Department of Chemical Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka, Koganei, Tokyo 184-8588, Japan.
| | - Ayaka Hosoe
- Department of Chemical Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka, Koganei, Tokyo 184-8588, Japan.
| | - Masaaki Hosomi
- Department of Chemical Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka, Koganei, Tokyo 184-8588, Japan.
| | - Akihiko Terada
- Department of Chemical Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka, Koganei, Tokyo 184-8588, Japan.
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115
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Gautam S, Kim T, Howell R, Spiegel DA. Fluorescent stem peptide mimics: In situ probes for peptidoglycan crosslinking. Methods Enzymol 2020; 638:57-67. [PMID: 32416921 DOI: 10.1016/bs.mie.2020.02.016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/17/2023]
Abstract
Understanding the mechanisms of bacterial cell wall synthesis is essential for microbiology and medicine alike. A key step in this process is peptidoglycan crosslinking, which confers mechanical strength to the cell wall and represents a target for numerous classes of antibiotics. However, the biology of crosslinking remains poorly understood due to a lack of tools for studying the reaction in vivo. Recently, we developed a class of synthetic probes called fluorescent stem peptide mimics (FSPMs) that meet this need, allowing quantification and localization of crosslinking activity in live bacteria. We have utilized FSPMs to describe novel aspects of peptidoglycan synthesis in the human pathogen, Staphylococcus aureus. To enable wider use of our methodology, we provide detailed protocols herein for the synthesis of FSPMs, labeling of live bacteria, and evaluation of crosslinking by flow cytometry and super-resolution microscopy. We believe that FSPMs, together with complementary biosynthetic probes and traditional bacteriologic methods, will help to advance our understanding of peptidoglycan biology and accelerate the search for new antibiotics.
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Affiliation(s)
- Samir Gautam
- Yale University School of Medicine, Department of Internal Medicine, Section of Pulmonary, Critical Care and Sleep Medicine, New Haven, CT, United States; Yale University, Department of Chemistry, New Haven, CT, United States
| | - Taehan Kim
- Yale University, Department of Chemistry, New Haven, CT, United States
| | - Rebecca Howell
- Yale University, Department of Chemistry, New Haven, CT, United States
| | - David A Spiegel
- Yale University, Department of Chemistry, New Haven, CT, United States.
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116
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Banner DJ, Firlar E, Jakubonis J, Baggia Y, Osborn JK, Shahbazian-Yassar R, Megaridis CM, Shokuhfar T. Correlative ex situ and Liquid-Cell TEM Observation of Bacterial Cell Membrane Damage Induced by Rough Surface Topology. Int J Nanomedicine 2020; 15:1929-1938. [PMID: 32256069 PMCID: PMC7093104 DOI: 10.2147/ijn.s232230] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Accepted: 01/27/2020] [Indexed: 01/07/2023] Open
Abstract
BACKGROUND Nanoscale surface roughness has been suggested to have antibacterial and antifouling properties. Several existing models have attempted to explain the antibacterial mechanism of nanoscale rough surfaces without direct observation. Here, conventional and liquid-cell TEM are implemented to observe nanoscale bacteria/surface roughness interaction. The visualization of such interactions enables the inference of possible antibacterial mechanisms. METHODS AND RESULTS Nanotextures are synthesized on biocompatible polymer microparticles (MPs) via plasma etching. Both conventional and liquid-phase transmission electron microscopy observations suggest that these MPs may cause cell lysis via bacterial binding to a single protrusion of the nanotexture. The bacterium/protrusion interaction locally compromises the cell wall, thus causing bacterial death. This study suggests that local mechanical damage and leakage of the cytosol kill the bacteria first, with subsequent degradation of the cell envelope. CONCLUSION Nanoscale surface roughness may act via a penetrative bactericidal mechanism. This insight suggests that future research may focus on optimizing bacterial binding to individual nanoscale projections in addition to stretching bacteria between nanopillars. Further, antibacterial nanotextures may find use in novel applications employing particles in addition to nanotextures on fibers or films.
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Affiliation(s)
- David J Banner
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL60607, USA
| | - Emre Firlar
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL60607, USA
- Department of Mechanical and Industrial Engineering, University of Illinois at Chicago, Chicago, IL60607, USA
| | - Justas Jakubonis
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL60607, USA
| | - Yusuf Baggia
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL60607, USA
| | - Jodi K Osborn
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL60607, USA
| | - Reza Shahbazian-Yassar
- Department of Mechanical and Industrial Engineering, University of Illinois at Chicago, Chicago, IL60607, USA
| | - Constantine M Megaridis
- Department of Mechanical and Industrial Engineering, University of Illinois at Chicago, Chicago, IL60607, USA
| | - Tolou Shokuhfar
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL60607, USA
- Department of Mechanical and Industrial Engineering, University of Illinois at Chicago, Chicago, IL60607, USA
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117
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Frenkel-Pinter M, Samanta M, Ashkenasy G, Leman LJ. Prebiotic Peptides: Molecular Hubs in the Origin of Life. Chem Rev 2020; 120:4707-4765. [PMID: 32101414 DOI: 10.1021/acs.chemrev.9b00664] [Citation(s) in RCA: 148] [Impact Index Per Article: 37.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The fundamental roles that peptides and proteins play in today's biology makes it almost indisputable that peptides were key players in the origin of life. Insofar as it is appropriate to extrapolate back from extant biology to the prebiotic world, one must acknowledge the critical importance that interconnected molecular networks, likely with peptides as key components, would have played in life's origin. In this review, we summarize chemical processes involving peptides that could have contributed to early chemical evolution, with an emphasis on molecular interactions between peptides and other classes of organic molecules. We first summarize mechanisms by which amino acids and similar building blocks could have been produced and elaborated into proto-peptides. Next, non-covalent interactions of peptides with other peptides as well as with nucleic acids, lipids, carbohydrates, metal ions, and aromatic molecules are discussed in relation to the possible roles of such interactions in chemical evolution of structure and function. Finally, we describe research involving structural alternatives to peptides and covalent adducts between amino acids/peptides and other classes of molecules. We propose that ample future breakthroughs in origin-of-life chemistry will stem from investigations of interconnected chemical systems in which synergistic interactions between different classes of molecules emerge.
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Affiliation(s)
- Moran Frenkel-Pinter
- NSF/NASA Center for Chemical Evolution, https://centerforchemicalevolution.com/.,School of Chemistry & Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Mousumi Samanta
- Department of Chemistry, Ben-Gurion University of the Negev, Beer Sheva 84105, Israel
| | - Gonen Ashkenasy
- Department of Chemistry, Ben-Gurion University of the Negev, Beer Sheva 84105, Israel
| | - Luke J Leman
- NSF/NASA Center for Chemical Evolution, https://centerforchemicalevolution.com/.,Department of Chemistry, The Scripps Research Institute, La Jolla, California 92037, United States
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118
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Jena P, Bhattacharya M, Bhattacharjee G, Satpati B, Mukherjee P, Senapati D, Srinivasan R. Bimetallic gold-silver nanoparticles mediate bacterial killing by disrupting the actin cytoskeleton MreB. NANOSCALE 2020; 12:3731-3749. [PMID: 31993609 DOI: 10.1039/c9nr10700b] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The actin cytoskeleton is required for the maintenance of the cell shape and viability of bacteria. It remains unknown to which extent nanoparticles (NPs) can orchestrate the mechanical instability by disrupting the cytoskeletal network in bacterial cells. Our work demonstrates that Au-Ag NPs disrupt the bacterial actin cytoskeleton specifically, fluidize the inner membrane and lead to killing of bacterial cells. In this study, we have tried to emphasize on the key parameters important for NP-cell interactions and found that the shape, specific elemental surface localization and enhanced electrostatic interaction developed due to the acquired partial positive charge by silver atoms in the aggregated NPs are some of the major factors contributing towards better NP interactions and subsequent cell death. In vivo studies in bacterial cells showed that the NPs exerted a mild perturbation of the membrane potential. However, its most striking effect was on the actin cytoskeleton MreB resulting in morphological changes in the bacterial cell shape from rods to predominantly spheres. Exposure to NPs resulted in the delocalization of MreB patches from the membrane but not the tubulin homologue FtsZ. Concomitant with the redistribution of MreB localization, a dramatic increase of membrane fluid regions was observed. Our studies reveal for the first time that Au-Ag NPs can mediate bacterial killing and disrupt the actin cytoskeletal functions in bacteria.
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Affiliation(s)
- Prajna Jena
- Centre for Research in Nanoscience and Nanotechnology, University of Calcutta, JD-2, sector -3, Salt Lake City, Kolkata, India.
| | - Maireyee Bhattacharya
- Chemical Sciences Division, Saha Institute of Nuclear Physics, HBNI, 1/AF, Bidhannagar, Kolkata-700064, India.
| | - Gourab Bhattacharjee
- Surface Physics and Materials Science Division, Saha Institute of Nuclear Physics, HBNI, 1/AF, Bidhannagar, Kolkata-700064, India
| | - Biswarup Satpati
- Surface Physics and Materials Science Division, Saha Institute of Nuclear Physics, HBNI, 1/AF, Bidhannagar, Kolkata-700064, India
| | - Prasun Mukherjee
- Centre for Research in Nanoscience and Nanotechnology, University of Calcutta, JD-2, sector -3, Salt Lake City, Kolkata, India.
| | - Dulal Senapati
- Chemical Sciences Division, Saha Institute of Nuclear Physics, HBNI, 1/AF, Bidhannagar, Kolkata-700064, India.
| | - Ramanujam Srinivasan
- School of Biological Sciences, National Institute of Science Education and Research (NISER), HBNI, Bhubaneswar, Odisha 752050, India.
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119
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Gunawan C, Faiz MB, Mann R, Ting SRS, Sotiriou GA, Marquis CP, Amal R. Nanosilver Targets the Bacterial Cell Envelope: The Link with Generation of Reactive Oxygen Radicals. ACS APPLIED MATERIALS & INTERFACES 2020; 12:5557-5568. [PMID: 31927911 DOI: 10.1021/acsami.9b20193] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The work describes the interactions of nanosilver (NAg) with bacterial cell envelope components at a molecular level and how this associates with the reactive oxygen species (ROS)-mediated toxicity of the nanoparticle. Major structural changes were detected in cell envelope biomolecules as a result of damages in functional moieties, such as the saccharides, amides, and phosphodiesters. NAg exposure disintegrates the glycan backbone in the major cell wall component peptidoglycan, causes complete breakdown of lipoteichoic acid, and disrupts the phosphate-amine and fatty acid groups in phosphatidylethanolamine, a membrane phospholipid. Consistent with the oxidative attacks, we propose that the observed cell envelope damages are inflicted, at least in part, by the reactive oxygen radicals being generated by the nanoparticle during its leaching process, abiotically, without cells. The cell envelope targeting, especially those on the inner membrane phospholipid, is likely to then trigger the rapid generation of lethal levels of cellular superoxide (O2•-) and hydroxyl (OH•) radicals herein seen with a model bacterium. The present study provides a better understanding of the antibacterial mechanisms of NAg, whereby ROS generation could be both the cause and consequence of the toxicity, associated with the initial cell envelope targeting by the nanoparticle.
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Affiliation(s)
- Cindy Gunawan
- ithree institute , University of Technology Sydney , Sydney , NSW 2007 , Australia
- School of Chemical Engineering , University of New South Wales , Sydney , NSW 2052 , Australia
| | - Merisa B Faiz
- School of Chemical Engineering , University of New South Wales , Sydney , NSW 2052 , Australia
| | - Riti Mann
- ithree institute , University of Technology Sydney , Sydney , NSW 2007 , Australia
| | - Simon R S Ting
- Centre for Health Technologies , University of Technology Sydney , Sydney NSW 2007 , Australia
| | - Georgios A Sotiriou
- Department of Microbiology, Tumor and Cell Biology , Karolinska Institutet , Solna, Stockholm 171 77 , Sweden
| | - Christopher P Marquis
- School of Biotechnology and Biomolecular Sciences , University of New South Wales , Sydney , NSW 2052 , Australia
| | - Rose Amal
- School of Chemical Engineering , University of New South Wales , Sydney , NSW 2052 , Australia
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120
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Elbourne A, Cheeseman S, Atkin P, Truong NP, Syed N, Zavabeti A, Mohiuddin M, Esrafilzadeh D, Cozzolino D, McConville CF, Dickey MD, Crawford RJ, Kalantar-Zadeh K, Chapman J, Daeneke T, Truong VK. Antibacterial Liquid Metals: Biofilm Treatment via Magnetic Activation. ACS NANO 2020; 14:802-817. [PMID: 31922722 DOI: 10.1021/acsnano.9b07861] [Citation(s) in RCA: 135] [Impact Index Per Article: 33.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Antibiotic resistance has made the treatment of biofilm-related infections challenging. As such, the quest for next-generation antimicrobial technologies must focus on targeted therapies to which pathogenic bacteria cannot develop resistance. Stimuli-responsive therapies represent an alternative technological focus due to their capability of delivering targeted treatment. This study provides a proof-of-concept investigation into the use of magneto-responsive gallium-based liquid metal (LM) droplets as antibacterial materials, which can physically damage, disintegrate, and kill pathogens within a mature biofilm. Once exposed to a low-intensity rotating magnetic field, the LM droplets become physically actuated and transform their shape, developing sharp edges. When placed in contact with a bacterial biofilm, the movement of the particles resulting from the magnetic field, coupled with the presence of nanosharp edges, physically ruptures the bacterial cells and the dense biofilm matrix is broken down. The antibacterial efficacy of the magnetically activated LM particles was assessed against both Gram-positive and Gram-negative bacterial biofilms. After 90 min over 99% of both bacterial species became nonviable, and the destruction of the biofilms was observed. These results will impact the design of next-generation, LM-based biofilm treatments.
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Affiliation(s)
- Aaron Elbourne
- School of Science, College of Science, Engineering and Health , RMIT University , Melbourne , Victoria 3001 , Australia
- Nanobiotechnology Laboratory , RMIT University , Melbourne , Victoria 3001 , Australia
| | - Samuel Cheeseman
- School of Science, College of Science, Engineering and Health , RMIT University , Melbourne , Victoria 3001 , Australia
- Nanobiotechnology Laboratory , RMIT University , Melbourne , Victoria 3001 , Australia
| | - Paul Atkin
- School of Engineering, College of Science, Engineering and Health , RMIT University , Melbourne , Victoria 3001 , Australia
- CSIRO Australia , Private Bag 33, Clayton South MDC , Clayton , Victoria 3169 , Australia
| | - Nghia P Truong
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash Institute of Pharmaceutical Sciences , Monash University , 399 Royal Parade , Parkville , Victoria 3152 , Australia
| | - Nitu Syed
- School of Engineering, College of Science, Engineering and Health , RMIT University , Melbourne , Victoria 3001 , Australia
| | - Ali Zavabeti
- School of Engineering, College of Science, Engineering and Health , RMIT University , Melbourne , Victoria 3001 , Australia
| | - Md Mohiuddin
- School of Engineering, College of Science, Engineering and Health , RMIT University , Melbourne , Victoria 3001 , Australia
| | - Dorna Esrafilzadeh
- School of Engineering, College of Science, Engineering and Health , RMIT University , Melbourne , Victoria 3001 , Australia
- Graduate School of Biomedical Engineering , University of New South Wales (UNSW) , Kensington , NSW 2052 , Australia
| | - Daniel Cozzolino
- School of Science, College of Science, Engineering and Health , RMIT University , Melbourne , Victoria 3001 , Australia
| | - Chris F McConville
- School of Science, College of Science, Engineering and Health , RMIT University , Melbourne , Victoria 3001 , Australia
| | - Michael D Dickey
- Department of Chemical and Biomolecular Engineering , North Carolina State University , Raleigh , North Carolina 27695 , United States
| | - Russell J Crawford
- School of Science, College of Science, Engineering and Health , RMIT University , Melbourne , Victoria 3001 , Australia
- Nanobiotechnology Laboratory , RMIT University , Melbourne , Victoria 3001 , Australia
| | - Kourosh Kalantar-Zadeh
- School of Chemical Engineering , University of New South Wales (UNSW) , Kensington , NSW 2052 , Australia
| | - James Chapman
- School of Science, College of Science, Engineering and Health , RMIT University , Melbourne , Victoria 3001 , Australia
- Nanobiotechnology Laboratory , RMIT University , Melbourne , Victoria 3001 , Australia
| | - Torben Daeneke
- School of Engineering, College of Science, Engineering and Health , RMIT University , Melbourne , Victoria 3001 , Australia
| | - Vi Khanh Truong
- School of Science, College of Science, Engineering and Health , RMIT University , Melbourne , Victoria 3001 , Australia
- Nanobiotechnology Laboratory , RMIT University , Melbourne , Victoria 3001 , Australia
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121
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Do T, Page JE, Walker S. Uncovering the activities, biological roles, and regulation of bacterial cell wall hydrolases and tailoring enzymes. J Biol Chem 2020; 295:3347-3361. [PMID: 31974163 DOI: 10.1074/jbc.rev119.010155] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Bacteria account for 1000-fold more biomass than humans. They vary widely in shape and size. The morphological diversity of bacteria is due largely to the different peptidoglycan-based cell wall structures that encase bacterial cells. Although the basic structure of peptidoglycan is highly conserved, consisting of long glycan strands that are cross-linked by short peptide chains, the mature cell wall is chemically diverse. Peptidoglycan hydrolases and cell wall-tailoring enzymes that regulate glycan strand length, the degree of cross-linking, and the addition of other modifications to peptidoglycan are central in determining the final architecture of the bacterial cell wall. Historically, it has been difficult to biochemically characterize these enzymes that act on peptidoglycan because suitable peptidoglycan substrates were inaccessible. In this review, we discuss fundamental aspects of bacterial cell wall synthesis, describe the regulation and diverse biochemical and functional activities of peptidoglycan hydrolases, and highlight recently developed methods to make and label defined peptidoglycan substrates. We also review how access to these substrates has now enabled biochemical studies that deepen our understanding of how bacterial cell wall enzymes cooperate to build a mature cell wall. Such improved understanding is critical to the development of new antibiotics that disrupt cell wall biogenesis, a process essential to the survival of bacteria.
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Affiliation(s)
- Truc Do
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts 02115
| | - Julia E Page
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts 02115
| | - Suzanne Walker
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts 02115.
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122
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Mechanomicrobiology: how bacteria sense and respond to forces. Nat Rev Microbiol 2020; 18:227-240. [DOI: 10.1038/s41579-019-0314-2] [Citation(s) in RCA: 99] [Impact Index Per Article: 24.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/06/2019] [Indexed: 12/26/2022]
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123
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Mechanical stress compromises multicomponent efflux complexes in bacteria. Proc Natl Acad Sci U S A 2019; 116:25462-25467. [PMID: 31772020 DOI: 10.1073/pnas.1909562116] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Physical forces have a profound effect on growth, morphology, locomotion, and survival of organisms. At the level of individual cells, the role of mechanical forces is well recognized in eukaryotic physiology, but much less is known about prokaryotic organisms. Recent findings suggest an effect of physical forces on bacterial shape, cell division, motility, virulence, and biofilm initiation, but it remains unclear how mechanical forces applied to a bacterium are translated at the molecular level. In Gram-negative bacteria, multicomponent protein complexes can form rigid links across the cell envelope and are therefore subject to physical forces experienced by the cell. Here we manipulate tensile and shear mechanical stress in the bacterial cell envelope and use single-molecule tracking to show that octahedral shear (but not hydrostatic) stress within the cell envelope promotes disassembly of the tripartite efflux complex CusCBA, a system used by Escherichia coli to resist copper and silver toxicity. By promoting disassembly of this protein complex, mechanical forces within the cell envelope make the bacteria more susceptible to metal toxicity. These findings demonstrate that mechanical forces can inhibit the function of cell envelope protein assemblies in bacteria and suggest the possibility that other multicomponent, transenvelope efflux complexes may be sensitive to mechanical forces including complexes involved in antibiotic resistance, cell division, and translocation of outer membrane components. By modulating the function of proteins within the cell envelope, mechanical stress has the potential to regulate multiple processes required for bacterial survival and growth.
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124
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Hassan AA, Vitorino MV, Robalo T, Rodrigues MS, Sá-Correia I. Variation of Burkholderia cenocepacia cell wall morphology and mechanical properties during cystic fibrosis lung infection, assessed by atomic force microscopy. Sci Rep 2019; 9:16118. [PMID: 31695169 PMCID: PMC6834607 DOI: 10.1038/s41598-019-52604-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Accepted: 10/21/2019] [Indexed: 12/13/2022] Open
Abstract
The influence that Burkholderia cenocepacia adaptive evolution during long-term infection in cystic fibrosis (CF) patients has on cell wall morphology and mechanical properties is poorly understood despite their crucial role in cell physiology, persistent infection and pathogenesis. Cell wall morphology and physical properties of three B. cenocepacia isolates collected from a CF patient over a period of 3.5 years were compared using atomic force microscopy (AFM). These serial clonal variants include the first isolate retrieved from the patient and two late isolates obtained after three years of infection and before the patient's death with cepacia syndrome. A consistent and progressive decrease of cell height and a cell shape evolution during infection, from the typical rods to morphology closer to cocci, were observed. The images of cells grown in biofilms showed an identical cell size reduction pattern. Additionally, the apparent elasticity modulus significantly decreases from the early isolate to the last clonal variant retrieved from the patient but the intermediary highly antibiotic resistant clonal isolate showed the highest elasticity values. Concerning the adhesion of bacteria surface to the AFM tip, the first isolate was found to adhere better than the late isolates whose lipopolysaccharide (LPS) structure loss the O-antigen (OAg) during CF infection. The OAg is known to influence Gram-negative bacteria adhesion and be an important factor in B. cenocepacia adaptation to chronic infection. Results reinforce the concept of the occurrence of phenotypic heterogeneity and adaptive evolution, also at the level of cell size, form, envelope topography and physical properties during long-term infection.
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Affiliation(s)
- A Amir Hassan
- iBB - Institute for Bioengineering and Biosciences, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, 1049-001, Portugal
- Department of Bioengineering, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, 1049-001, Portugal
| | - Miguel V Vitorino
- BioISI - Biosystems and Integrative Sciences Institute, Faculdade de Ciências, Universidade de Lisboa, 1749-016, Lisboa, Portugal
- Departamento de Física, Faculdade de Ciências, Universidade de Lisboa, 1749-016, Lisboa, Portugal
| | - Tiago Robalo
- BioISI - Biosystems and Integrative Sciences Institute, Faculdade de Ciências, Universidade de Lisboa, 1749-016, Lisboa, Portugal
| | - Mário S Rodrigues
- BioISI - Biosystems and Integrative Sciences Institute, Faculdade de Ciências, Universidade de Lisboa, 1749-016, Lisboa, Portugal.
- Departamento de Física, Faculdade de Ciências, Universidade de Lisboa, 1749-016, Lisboa, Portugal.
| | - Isabel Sá-Correia
- iBB - Institute for Bioengineering and Biosciences, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, 1049-001, Portugal.
- Department of Bioengineering, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, 1049-001, Portugal.
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125
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Tan F, She P, Zhou L, Liu Y, Chen L, Luo Z, Wu Y. Bactericidal and Anti-biofilm Activity of the Retinoid Compound CD437 Against Enterococcus faecalis. Front Microbiol 2019; 10:2301. [PMID: 31649642 PMCID: PMC6794434 DOI: 10.3389/fmicb.2019.02301] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Accepted: 09/20/2019] [Indexed: 01/24/2023] Open
Abstract
Enterococcus faecalis (E. faecalis), a biofilm-forming pathogen, causes nosocomial infections. In recent years, drug resistance by enterococci has become increasingly severe due to widespread antibiotic abuse. Therefore, novel antibacterial agents are urgently needed. In this study, the synthetic retinoid compound CD437 was found to have potent bactericidal effect on E. faecalis. In addition, CD437 exhibited synergistic effects when administered in combination with gentamicin and additive effects when combined with ceftriaxone sodium. CD437 also inhibited biofilm formation by E. faecalis and exerted bactericidal effect on mature biofilm. Moreover, CD437 exhibited antibacterial and anti-biofilm effects against Staphylococcus. No bactericidal action of CD437 was observed against the gram-negative bacillus, but Pseudomonas aeruginosa biofilm extracellular polymeric substances (EPS) matrix formation was reduced. Overall, these findings indicate that CD437 has the potential to be developed as a novel antibacterial drug.
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Affiliation(s)
- Fang Tan
- Department of Medicine Clinical Laboratory, The Third Xiangya Hospital of Central South University, Changsha, China
| | - Pengfei She
- Department of Medicine Clinical Laboratory, The Third Xiangya Hospital of Central South University, Changsha, China
| | - Linying Zhou
- Department of Medicine Clinical Laboratory, The Third Xiangya Hospital of Central South University, Changsha, China
| | - Yiqing Liu
- Department of Medicine Clinical Laboratory, The Third Xiangya Hospital of Central South University, Changsha, China
| | - Lihua Chen
- Department of Medicine Clinical Laboratory, The Third Xiangya Hospital of Central South University, Changsha, China
| | - Zhen Luo
- Department of Medicine Clinical Laboratory, The Third Xiangya Hospital of Central South University, Changsha, China
| | - Yong Wu
- Department of Medicine Clinical Laboratory, The Third Xiangya Hospital of Central South University, Changsha, China
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126
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Bacterial Swarming Reduces Proteus mirabilis and Vibrio parahaemolyticus Cell Stiffness and Increases β-Lactam Susceptibility. mBio 2019; 10:mBio.00210-19. [PMID: 31594808 PMCID: PMC6786863 DOI: 10.1128/mbio.00210-19] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Proteus mirabilis and Vibrio parahaemolyticus are bacteria that infect humans. To adapt to environmental changes, these bacteria alter their cell morphology and move collectively to access new sources of nutrients in a process referred to as “swarming.” We found that changes in the composition and thickness of the peptidoglycan layer of the cell wall make swarmer cells of P. mirabilis and V. parahaemolyticus more flexible (i.e., reduce cell stiffness) and that they become more sensitive to osmotic pressure and cell wall-targeting antibiotics (e.g., β-lactams). These results highlight the importance of assessing the extracellular environment in determining antibiotic doses and the use of β-lactam antibiotics for treating infections caused by swarmer cells of P. mirabilis and V. parahaemolyticus. Swarmer cells of the Gram-negative uropathogenic bacteria Proteus mirabilis and Vibrio parahaemolyticus become long (>10 to 100 μm) and multinucleate during their growth and motility on polymer surfaces. We demonstrated that the increasing cell length is accompanied by a large increase in flexibility. Using a microfluidic assay to measure single-cell mechanics, we identified large differences in the swarmer cell stiffness (bending rigidity) of P. mirabilis (5.5 × 10−22 N m2) and V. parahaemolyticus (1.0 × 10−22 N m2) compared to vegetative cells (1.4 × 10−20 N m2 and 2.2 × 10−22 N m2, respectively). The reduction in bending rigidity (∼2-fold to ∼26-fold) was accompanied by a decrease in the average polysaccharide strand length of the peptidoglycan layer of the cell wall from 28 to 30 disaccharides to 19 to 22 disaccharides. Atomic force microscopy revealed a reduction in P. mirabilis peptidoglycan thickness from 1.5 nm (vegetative cells) to 1.0 nm (swarmer cells), and electron cryotomography indicated changes in swarmer cell wall morphology. P. mirabilis and V. parahaemolyticus swarmer cells became increasingly sensitive to osmotic pressure and susceptible to cell wall-modifying antibiotics (compared to vegetative cells)—they were ∼30% more likely to die after 3 h of treatment with MICs of the β-lactams cephalexin and penicillin G. The adaptive cost of “swarming” was offset by the increase in cell susceptibility to physical and chemical changes in their environment, thereby suggesting the development of new chemotherapies for bacteria that leverage swarming for the colonization of hosts and for survival.
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127
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Wang Z, Zhu X, Su Y, Xu W, Liu H, Liu Z, Chen W, Wang J. Dimethyl phthalate damaged the cell membrane of Escherichia coli K12. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2019; 180:208-214. [PMID: 31096126 DOI: 10.1016/j.ecoenv.2019.05.009] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Revised: 04/25/2019] [Accepted: 05/02/2019] [Indexed: 05/22/2023]
Abstract
Dimethyl phthalate (DMP), a phthalate ester (PAE), is a ubiquitous and organic pollutant. In this study, the toxicity of DMP to Escherichia coli K12 and its underlying mechanism were investigated. The results showed that DMP inhibited the growth of E. coli K12 and induced cell inactivation and/or death. DMP caused serious damage to the cell membrane of E. coli K12, and the damage increased with higher DMP concentrations. DMP exposure disrupted cell membranes, as evidenced by dose-dependent variations of cell structures, surface properties, and membrane compositions. Increases in the malondialdehyde (MDA) content indicated an increase in oxidative stress induced by DMP in E. coli K12. The activity of succinic dehydrogenase (SDH) was changed by DMP, which could affect energy metabolism in the membrane of E. coli K12. The expression levels of OmpA and OmpX were increased, and the expression levels of OmpF and OmpW were decreased, in E. coli K12 exposed to DMP. The toxicities of DMP to E. coli K12 could be ascribed to membrane disruption and oxidative stress-induced cell inactivation and/or death. The outcomes will shed new light on the assessment of the ecological effects of DMP.
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Affiliation(s)
- Zhigang Wang
- School of Life Science and Agriculture and Forestry, Qiqihar University, Qiqihar, Heilongjiang, 161006, China
| | - Xiaohui Zhu
- School of Life Science and Agriculture and Forestry, Qiqihar University, Qiqihar, Heilongjiang, 161006, China
| | - Yunpeng Su
- School of Life Science and Agriculture and Forestry, Qiqihar University, Qiqihar, Heilongjiang, 161006, China
| | - Weihui Xu
- School of Life Science and Agriculture and Forestry, Qiqihar University, Qiqihar, Heilongjiang, 161006, China.
| | - Hong Liu
- School of Life Science and Agriculture and Forestry, Qiqihar University, Qiqihar, Heilongjiang, 161006, China
| | - Zeping Liu
- School of Life Science and Agriculture and Forestry, Qiqihar University, Qiqihar, Heilongjiang, 161006, China
| | - Wenjing Chen
- School of Life Science and Agriculture and Forestry, Qiqihar University, Qiqihar, Heilongjiang, 161006, China
| | - Junhe Wang
- Qiqihar Branch of Heilongjiang Academy of Agricultural Sciences, Qiqihar, Heilongjiang, 161006, China
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128
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Martins ER, Díaz IEC, Paciencia MLB, Fana SA, Morais D, Eberlin MN, Silva JS, Silveira ER, Barros MP, Suffredini IB. Interference of Seasonal Variation on the Antimicrobial and Cytotoxic Activities of the Essential Oils from the Leaves of Iryanthera polyneura in the Amazon Rain Forest. Chem Biodivers 2019; 16:e1900374. [PMID: 31441194 DOI: 10.1002/cbdv.201900374] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Accepted: 08/22/2019] [Indexed: 11/06/2022]
Abstract
The essential oils (EOs) obtained from the leaves of Iryanthera polyneura Ducke trees was chemically Assessed and tested for the ability of inhibiting the growth of Candida albicans, Enterococcus faecalis, Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Streptococcus mutans and S. sanguinis. The oil was also tested against breast (MCF-7) and prostate (PC-3) cancer cell lines. Minimum bactericidal concentrations (MBCs) and 50 % inhibition concentrations (IC50 ) values were obtained. EOs were active against Gram-positive bacteria. Spathulenol, α-cadinol and τ-muurolol were major components of EOs. The oils showed a higher cytotoxicity against PC-3 than MCF-7 cells, although the oils were active against both cell types. Oils obtained from leaves collected in the dry season were more active against E. faecalis, S. aureus and PC-3, while the oils obtained from leaves collected in the rainy season were more active against S. mutans, S. sanguinis and MCF-7. The antibacterial and cytotoxic activities of the essential oils from the leaves of I. polyneura are related to the seasonal climate variation and are influenced by compounds that are minor components of the oils.
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Affiliation(s)
- Erika R Martins
- Graduate Program in Environmental and Experimental Pathology, Paulista University, R. Dr. Bacelar, 1212, Vila Clementino, São Paulo, SP 04026-002, Brazil
| | - Ingrit E C Díaz
- Chemistry Engineer Department, Chemistry and Textile Engineer Faculty, Engineer National University, Av. Tupac Amaru, 290, Rimac Apartado, 1301, Lima, Peru
| | - Mateus L B Paciencia
- Center for Research in Biodiversity, Paulista University, Av. Paulista, 900, Bela Vista, São Paulo, SP 01310-100, Brazil
| | - Sergio A Fana
- Graduate Program in Environmental and Experimental Pathology, Paulista University, R. Dr. Bacelar, 1212, Vila Clementino, São Paulo, SP 04026-002, Brazil.,Center for Research in Biodiversity, Paulista University, Av. Paulista, 900, Bela Vista, São Paulo, SP 01310-100, Brazil
| | - Damila Morais
- ThomSon Laboratory, Chemistry Institute, Universidade de Campinas - UNICAMP, Caixa Postal, 6154, SP, Brazil
| | - Marcos N Eberlin
- School of Engineering, Mackenzie Presbyterian University, R. Consolação, 930, São Paulo, SP 01302-907, Brazil
| | - Jefferson S Silva
- Graduate Program in Environmental and Experimental Pathology, Paulista University, R. Dr. Bacelar, 1212, Vila Clementino, São Paulo, SP 04026-002, Brazil.,Center for Research in Biodiversity, Paulista University, Av. Paulista, 900, Bela Vista, São Paulo, SP 01310-100, Brazil
| | - Elielson R Silveira
- Biological Sciences Course, Paulista University, R. Vergueiro, 1211, São Paulo, SP 01504-000, Brazil
| | - Matheus P Barros
- Biological Sciences Course, Paulista University, R. Vergueiro, 1211, São Paulo, SP 01504-000, Brazil
| | - Ivana B Suffredini
- Graduate Program in Environmental and Experimental Pathology, Paulista University, R. Dr. Bacelar, 1212, Vila Clementino, São Paulo, SP 04026-002, Brazil.,Center for Research in Biodiversity, Paulista University, Av. Paulista, 900, Bela Vista, São Paulo, SP 01310-100, Brazil
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129
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Ohta J, Sakurada K. Oral gram-positive bacterial DNA-based identification of saliva from highly degraded samples. Forensic Sci Int Genet 2019; 42:103-112. [DOI: 10.1016/j.fsigen.2019.06.016] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Revised: 06/17/2019] [Accepted: 06/22/2019] [Indexed: 12/29/2022]
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130
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Phenotypic plasticity of Escherichia coli upon exposure to physical stress induced by ZnO nanorods. Sci Rep 2019; 9:8575. [PMID: 31189961 PMCID: PMC6561948 DOI: 10.1038/s41598-019-44727-w] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Accepted: 05/23/2019] [Indexed: 11/17/2022] Open
Abstract
Evolution of bacteria to selective chemical pressure (e.g. antibiotics) is well studied in contrast to the influence of physical stressors. Here we show that instantaneous physical stress in a homogeneous environment (without concentration gradient) induces fast adaptation of Escherichia coli. We exposed E. coli to a large number of collisions of around 105 per bacterium per second with sharp ZnO nanorods. The pressure exerted on the bacterial cell wall was up to 10 GPa and induced phenotype changes. The bacteria’s shape became more spherical, the density of their periplasm increased by around 15% and the average thickness of the cell wall by 30%. Such E. coli cells appeared almost as Gram-positive bacteria in the standard Gram staining. Additionally, we observed a combination of changes occurring at the genomic level (mutations identified in form of single nucleotide polymorphisms) and down-regulation of expression of 61 genes encoding proteins involved in β-oxidation of fatty acids, glycolysis, the citric acid cycle, as well as uptake of amino acids and enzyme cofactors. Thus, we show that bacteria undergo phenotypic changes upon instantaneous, acute physical stress without any obviously available time for gradual adaptation.
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131
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Collett S, Torresi J, Earnest-Silveira L, Christiansen D, Elbourne A, Ramsland PA. Probing and pressing surfaces of hepatitis C virus-like particles. J Colloid Interface Sci 2019; 545:259-268. [DOI: 10.1016/j.jcis.2019.03.022] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Revised: 03/07/2019] [Accepted: 03/09/2019] [Indexed: 02/09/2023]
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132
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Elbourne A, Chapman J, Gelmi A, Cozzolino D, Crawford RJ, Truong VK. Bacterial-nanostructure interactions: The role of cell elasticity and adhesion forces. J Colloid Interface Sci 2019; 546:192-210. [PMID: 30921674 DOI: 10.1016/j.jcis.2019.03.050] [Citation(s) in RCA: 77] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Revised: 03/13/2019] [Accepted: 03/14/2019] [Indexed: 02/07/2023]
Abstract
The attachment of single-celled organisms, namely bacteria and fungi, to abiotic surfaces is of great interest to both the scientific and medical communities. This is because the interaction of such cells has important implications in a range of areas, including biofilm formation, biofouling, antimicrobial surface technologies, and bio-nanotechnologies, as well as infection development, control, and mitigation. While central to many biological phenomena, the factors which govern microbial surface attachment are still not fully understood. This lack of understanding is a direct consequence of the complex nature of cell-surface interactions, which can involve both specific and non-specific interactions. For applications involving micro- and nano-structured surfaces, developing an understanding of such phenomenon is further complicated by the diverse nature of surface architectures, surface chemistry, variation in cellular physiology, and the intended technological output. These factors are extremely important to understand in the emerging field of antibacterial nanostructured surfaces. The aim of this perspective is to re-frame the discussion surrounding the mechanism of nanostructured-microbial surface interactions. Broadly, the article reviews our current understanding of these phenomena, while highlighting the knowledge gaps surrounding the adhesive forces which govern bacterial-nanostructure interactions and the role of cell membrane rigidity in modulating surface activity. The roles of surface charge, cell rigidity, and cell-surface adhesion force in bacterial-surface adsorption are discussed in detail. Presently, most studies have overlooked these areas, which has left many questions unanswered. Further, this perspective article highlights the numerous experimental issues and misinterpretations which surround current studies of antibacterial nanostructured surfaces.
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Affiliation(s)
- Aaron Elbourne
- School of Science, College of Science, Engineering and Health, RMIT University, Melbourne, VIC 3001, Australia; Nanobiotechnology Laboratory, RMIT University, Melbourne, VIC 3001, Australia.
| | - James Chapman
- School of Science, College of Science, Engineering and Health, RMIT University, Melbourne, VIC 3001, Australia; Nanobiotechnology Laboratory, RMIT University, Melbourne, VIC 3001, Australia
| | - Amy Gelmi
- School of Science, College of Science, Engineering and Health, RMIT University, Melbourne, VIC 3001, Australia
| | - Daniel Cozzolino
- School of Science, College of Science, Engineering and Health, RMIT University, Melbourne, VIC 3001, Australia
| | - Russell J Crawford
- School of Science, College of Science, Engineering and Health, RMIT University, Melbourne, VIC 3001, Australia; Nanobiotechnology Laboratory, RMIT University, Melbourne, VIC 3001, Australia
| | - Vi Khanh Truong
- School of Science, College of Science, Engineering and Health, RMIT University, Melbourne, VIC 3001, Australia; Nanobiotechnology Laboratory, RMIT University, Melbourne, VIC 3001, Australia
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133
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Elbourne A, Truong VK, Cheeseman S, Rajapaksha P, Gangadoo S, Chapman J, Crawford RJ. The use of nanomaterials for the mitigation of pathogenic biofilm formation. METHODS IN MICROBIOLOGY 2019. [DOI: 10.1016/bs.mim.2019.04.002] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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134
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Smolková B, Uzhytchak M, Lynnyk A, Kubinová Š, Dejneka A, Lunov O. A Critical Review on Selected External Physical Cues and Modulation of Cell Behavior: Magnetic Nanoparticles, Non-thermal Plasma and Lasers. J Funct Biomater 2018; 10:jfb10010002. [PMID: 30586923 PMCID: PMC6463085 DOI: 10.3390/jfb10010002] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Revised: 12/13/2018] [Accepted: 12/21/2018] [Indexed: 12/18/2022] Open
Abstract
Physics-based biomedical approaches have proved their importance for the advancement of medical sciences and especially in medical diagnostics and treatments. Thus, the expectations regarding development of novel promising physics-based technologies and tools are very high. This review describes the latest research advances in biomedical applications of external physical cues. We overview three distinct topics: using high-gradient magnetic fields in nanoparticle-mediated cell responses; non-thermal plasma as a novel bactericidal agent; highlights in understanding of cellular mechanisms of laser irradiation. Furthermore, we summarize the progress, challenges and opportunities in those directions. We also discuss some of the fundamental physical principles involved in the application of each cue. Considerable technological success has been achieved in those fields. However, for the successful clinical translation we have to understand the limitations of technologies. Importantly, we identify the misconceptions pervasive in the discussed fields.
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Affiliation(s)
- Barbora Smolková
- Institute of Physics of the Czech Academy of Sciences, 18221 Prague, Czech Republic.
| | - Mariia Uzhytchak
- Institute of Physics of the Czech Academy of Sciences, 18221 Prague, Czech Republic.
| | - Anna Lynnyk
- Institute of Physics of the Czech Academy of Sciences, 18221 Prague, Czech Republic.
| | - Šárka Kubinová
- Institute of Physics of the Czech Academy of Sciences, 18221 Prague, Czech Republic.
- Institute of Experimental Medicine of the Czech Academy of Sciences, 14220 Prague, Czech Republic.
| | - Alexandr Dejneka
- Institute of Physics of the Czech Academy of Sciences, 18221 Prague, Czech Republic.
| | - Oleg Lunov
- Institute of Physics of the Czech Academy of Sciences, 18221 Prague, Czech Republic.
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135
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Mechanical Genomic Studies Reveal the Role of d-Alanine Metabolism in Pseudomonas aeruginosa Cell Stiffness. mBio 2018; 9:mBio.01340-18. [PMID: 30206169 PMCID: PMC6134093 DOI: 10.1128/mbio.01340-18] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The mechanical properties of bacteria are important for protecting cells against physical stress. The cell wall is the best-characterized cellular element contributing to bacterial cell mechanics; however, the biochemistry underlying its regulation and assembly is still not completely understood. Using a unique high-throughput biophysical assay, we identified genes coding proteins that modulate cell stiffness in the opportunistic human pathogen Pseudomonas aeruginosa. This approach enabled us to discover proteins with roles in a diverse range of biochemical pathways that influence the stiffness of P. aeruginosa cells. We demonstrate that d-Ala—a component of the peptidoglycan—is tightly regulated in cells and that its accumulation reduces expression of machinery that cross-links this material and decreases cell stiffness. This research demonstrates that there is much to learn about mechanical regulation in bacteria, and these studies revealed new nonessential P. aeruginosa targets that may enhance antibacterial chemotherapies or lead to new approaches. The stiffness of bacteria prevents cells from bursting due to the large osmotic pressure across the cell wall. Many successful antibiotic chemotherapies target elements that alter mechanical properties of bacteria, and yet a global view of the biochemistry underlying the regulation of bacterial cell stiffness is still emerging. This connection is particularly interesting in opportunistic human pathogens such as Pseudomonas aeruginosa that have a large (80%) proportion of genes of unknown function and low susceptibility to different families of antibiotics, including beta-lactams, aminoglycosides, and quinolones. We used a high-throughput technique to study a library of 5,790 loss-of-function mutants covering ~80% of the nonessential genes and correlated P. aeruginosa individual genes with cell stiffness. We identified 42 genes coding for proteins with diverse functions that, when deleted individually, decreased cell stiffness by >20%. This approach enabled us to construct a “mechanical genome” for P. aeruginosa. d-Alanine dehydrogenase (DadA) is an enzyme that converts d-Ala to pyruvate that was included among the hits; when DadA was deleted, cell stiffness decreased by 18% (using multiple assays to measure mechanics). An increase in the concentration of d-Ala in cells downregulated the expression of genes in peptidoglycan (PG) biosynthesis, including the peptidoglycan-cross-linking transpeptidase genes ponA and dacC. Consistent with this observation, ultraperformance liquid chromatography-mass spectrometry analysis of murein from P. aeruginosa cells revealed that dadA deletion mutants contained PG with reduced cross-linking and altered composition compared to wild-type cells.
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136
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Lessen HJ, Fleming PJ, Fleming KG, Sodt AJ. Building Blocks of the Outer Membrane: Calculating a General Elastic Energy Model for β-Barrel Membrane Proteins. J Chem Theory Comput 2018; 14:4487-4497. [PMID: 29979594 PMCID: PMC6191857 DOI: 10.1021/acs.jctc.8b00377] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The outer membranes of Gram negative bacteria are the first points of contact these organisms make with their environment. Understanding how composition determines the mechanical properties of this essential barrier is of paramount importance. Therefore, we developed a new computational method to measure the elasticity of transmembrane proteins found in the outer membrane. Using all-atom molecular dynamics simulations of these proteins, we apply a set of external forces to mechanically stress the transmembrane β-barrels. Our results from four representative β-barrels show that outer membrane proteins display elastic properties that are approximately 70 to 190 times stiffer than neat lipid membranes. These findings suggest that outer membrane β-barrels are a significant source of mechanical stability in bacteria. Our all-atom approach further reveals that resistance to radial stress is encoded by a general mechanism that includes stretching of backbone hydrogen bonds and tilting of β-strands with respect to the bilayer normal. This computational framework facilitates an increased theoretical understanding of how varying lipid and protein amounts affect the mechanical properties of the bacterial outer membrane.
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Affiliation(s)
- Henry J. Lessen
- T. C. Jenkins Department of Biophysics, Johns Hopkins University, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health
| | - Patrick J. Fleming
- T. C. Jenkins Department of Biophysics, Johns Hopkins University, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health
| | - Karen G. Fleming
- T. C. Jenkins Department of Biophysics, Johns Hopkins University, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health
| | - Alexander J. Sodt
- T. C. Jenkins Department of Biophysics, Johns Hopkins University, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health
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137
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Watanabe G, Sekiya H, Tamai E, Saijo R, Uno H, Mori S, Tanaka T, Maki J, Kawase M. Synthesis and Antimicrobial Activity of 2-Trifluoroacetonylbenzoxazole Ligands and Their Metal Complexes. Chem Pharm Bull (Tokyo) 2018; 66:732-740. [PMID: 29962457 DOI: 10.1248/cpb.c18-00158] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Three 2-fluoroacetonylbenzoxazole ligands 1a-c and their new Zn(II) complexes 2a-c have been synthesized. In addition, syntheses of new metal [Mg(II), Ni(II), Cu(II), Pd(II), and Ag(I)] complexes from 1a have been also described. The molecular and crystal structures of six metal complexes 2b and 2d-h were determined by single-crystal X-ray diffraction analyses. Their antibacterial activities against six Gram-positive and six Gram-negative bacteria were evaluated by minimum inhibitory concentrations (MIC), which were compared with those of appropriate antibiotics and silver nitrate. The results indicate that some metal compounds have more antibacterial effects in comparison with free ligands and have preferred antibacterial activities that may have potential pharmaceutical applications. Noticeably, the Ag(I) complex 2h exhibited low MIC value of 0.7 µM against Pseudomonas aeruginosa, which was even superior to the reference drug, Norfloxacin with that of 1.5 µM. Against P. aeruginosa, 2h is bacteriostatic, exerts the cell surface damage observed by scanning electron microscopy (SEM) and is less likely to develop resistance. The new 2h has been found to display effective antimicrobial activity against a series of bacteria.
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Affiliation(s)
- Genki Watanabe
- Faculty of Pharmaceutical Sciences, Matsuyama University
| | - Hiroshi Sekiya
- Department of Infectious Diseases, College of Pharmaceutical Sciences, Matsuyama University
| | - Eiji Tamai
- Department of Infectious Diseases, College of Pharmaceutical Sciences, Matsuyama University
| | - Ryosuke Saijo
- Faculty of Pharmaceutical Sciences, Matsuyama University
| | - Hidemitsu Uno
- Department of Chemistry and Biology, Graduate School of Science and Engineering, Ehime University
| | - Shigeki Mori
- Advanced Research Support Center, Ehime University
| | - Toru Tanaka
- Faculty of Pharmacy and Pharmaceutical Sciences, Josai University
| | - Jun Maki
- Department of Infectious Diseases, College of Pharmaceutical Sciences, Matsuyama University
| | - Masami Kawase
- Faculty of Pharmaceutical Sciences, Matsuyama University
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138
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Nanobiostructure of fibrous-like alumina functionalized with an analog of the BP100 peptide: Synthesis, characterization and biological applications. Colloids Surf B Biointerfaces 2018; 163:275-283. [DOI: 10.1016/j.colsurfb.2018.01.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Revised: 12/11/2017] [Accepted: 01/02/2018] [Indexed: 12/17/2022]
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139
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Letarov AV, Kulikov EE. Adsorption of bacteriophages on bacterial cells. BIOCHEMISTRY (MOSCOW) 2018. [DOI: 10.1134/s0006297917130053] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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140
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Chao HH, Chen PY, Hao WR, Chiang WP, Cheng TH, Loh SH, Leung YM, Liu JC, Chen JJ, Sung LC. Lipopolysaccharide pretreatment increases protease-activated receptor-2 expression and monocyte chemoattractant protein-1 secretion in vascular endothelial cells. J Biomed Sci 2017; 24:85. [PMID: 29141644 PMCID: PMC5688698 DOI: 10.1186/s12929-017-0393-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2017] [Accepted: 11/07/2017] [Indexed: 01/22/2023] Open
Abstract
Background This study investigated whether lipopolysaccharide (LPS) increase protease-activated receptor-2 (PAR-2) expression and enhance the association between PAR-2 expression and chemokine production in human vascular endothelial cells (ECs). Methods The morphology of ECs was observed through microphotography in cultured human umbilical vein ECs (EA. hy926 cells) treated with various LPS concentrations (0, 0.25, 0.5, 1, and 2 μg/mL) for 24 h, and cell viability was assessed using the MTT assay. Intracellular calcium imaging was performed to assess agonist (trypsin)-induced PAR-2 activity. Western blotting was used to explore the LPS-mediated signal transduction pathway and the expression of PAR-2 and adhesion molecule monocyte chemoattractant protein-1 (MCP-1) in ECs. Results Trypsin stimulation increased intracellular calcium release in ECs. The calcium influx was augmented in cells pretreated with a high LPS concentration (1 μg/mL). After 24 h treatment of LPS, no changes in ECs viability or morphology were observed. Western blotting revealed that LPS increased PAR-2 expression and enhanced trypsin-induced extracellular signal-regulated kinase (ERK)/p38 phosphorylation and MCP-1 secretion. However, pretreatment with selective ERK (PD98059), p38 mitogen-activated protein kinase (MAPK) (SB203580) inhibitors, and the selective PAR-2 antagonist (FSLLRY-NH2) blocked the effects of LPS-activated PAR-2 on MCP-1 secretion. Conclusions Our findings provide the first evidence that the bacterial endotoxin LPS potentiates calcium mobilization and ERK/p38 MAPK pathway activation and leads to the secretion of the pro-inflammatory chemokine MCP-1 by inducing PAR-2 expression and its associated activity in vascular ECs. Therefore, PAR-2 exerts vascular inflammatory effects and plays an important role in bacterial infection-induced pathological responses. Electronic supplementary material The online version of this article (10.1186/s12929-017-0393-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Hung-Hsing Chao
- Division of Cardiovascular Surgery, Department of Surgery, Shin Kong Wu Ho-Su Memorial Hospital, Taipei, 111, Taiwan.,Department of Surgery, School of Medicine, Taipei Medical University, Taipei, 11031, Taiwan
| | - Po-Yuan Chen
- Department of Biological Science and Technology, College of Biopharmaceutical and Food Sciences, China Medical University, Taichung, 40402, Taiwan
| | - Wen-Rui Hao
- Division of Cardiology, Department of Internal Medicine, Shuang Ho Hospital, Taipei Medical University, No. 291, Zhongzheng Rd, Zhonghe District, New Taipei City, 23561, Taiwan
| | - Wei-Ping Chiang
- Division of Cardiology, Department of Internal Medicine, Shuang Ho Hospital, Taipei Medical University, No. 291, Zhongzheng Rd, Zhonghe District, New Taipei City, 23561, Taiwan
| | - Tzu-Hurng Cheng
- Department of Biochemistry, School of Medicine, China Medical University, Taichung, 40402, Taiwan.,Department of Pharmacology & Graduate Institute of Pharmacology, National Defense Medical Center, Taipei, 114, Taiwan
| | - Shih-Hurng Loh
- Department of Pharmacology & Graduate Institute of Pharmacology, National Defense Medical Center, Taipei, 114, Taiwan
| | - Yuk-Man Leung
- Department of Physiology, School of Medicine, China Medical University, Taichung, 40402, Taiwan
| | - Ju-Chi Liu
- Division of Cardiology, Department of Internal Medicine, Shuang Ho Hospital, Taipei Medical University, No. 291, Zhongzheng Rd, Zhonghe District, New Taipei City, 23561, Taiwan.,Department of Internal Medicine, School of Medicine, College of Medicine, Taipei Medical University, Taipei, 11031, Taiwan
| | - Jin-Jer Chen
- Graduate Institute of Clinical Medicine, College of Medicine, China Medical University, Taichung, 40402, Taiwan.,Institute of Biomedical Sciences, Academia Sinica, Taipei, 115, Taiwan
| | - Li-Chin Sung
- Division of Cardiology, Department of Internal Medicine, Shuang Ho Hospital, Taipei Medical University, No. 291, Zhongzheng Rd, Zhonghe District, New Taipei City, 23561, Taiwan. .,Department of Internal Medicine, School of Medicine, College of Medicine, Taipei Medical University, Taipei, 11031, Taiwan.
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