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Lee TH, Charchar P, Separovic F, Reid GE, Yarovsky I, Aguilar MI. The intricate link between membrane lipid structure and composition and membrane structural properties in bacterial membranes. Chem Sci 2024; 15:3408-3427. [PMID: 38455013 PMCID: PMC10915831 DOI: 10.1039/d3sc04523d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2023] [Accepted: 01/26/2024] [Indexed: 03/09/2024] Open
Abstract
It is now evident that the cell manipulates lipid composition to regulate different processes such as membrane protein insertion, assembly and function. Moreover, changes in membrane structure and properties, lipid homeostasis during growth and differentiation with associated changes in cell size and shape, and responses to external stress have been related to drug resistance across mammalian species and a range of microorganisms. While it is well known that the biomembrane is a fluid self-assembled nanostructure, the link between the lipid components and the structural properties of the lipid bilayer are not well understood. This perspective aims to address this topic with a view to a more detailed understanding of the factors that regulate bilayer structure and flexibility. We describe a selection of recent studies that address the dynamic nature of bacterial lipid diversity and membrane properties in response to stress conditions. This emerging area has important implications for a broad range of cellular processes and may open new avenues of drug design for selective cell targeting.
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Affiliation(s)
- Tzong-Hsien Lee
- Department of Biochemistry and Molecular Biology, Monash University Clayton VIC 3800 Australia
| | - Patrick Charchar
- School of Engineering, RMIT University Melbourne Victoria 3001 Australia
| | - Frances Separovic
- School of Chemistry, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne VIC 3010 Australia
| | - Gavin E Reid
- School of Chemistry, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne VIC 3010 Australia
- Department of Biochemistry and Pharmacology, University of Melbourne Parkville VIC 3010 Australia
| | - Irene Yarovsky
- School of Engineering, RMIT University Melbourne Victoria 3001 Australia
| | - Marie-Isabel Aguilar
- Department of Biochemistry and Molecular Biology, Monash University Clayton VIC 3800 Australia
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Photodynamic effect of TPP encapsulated in polystyrene nanoparticles toward multi-resistant pathogenic bacterial strains: AFM evaluation. Sci Rep 2021; 11:6786. [PMID: 33762617 PMCID: PMC7990921 DOI: 10.1038/s41598-021-85828-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Accepted: 03/01/2021] [Indexed: 12/14/2022] Open
Abstract
Photodynamic inactivation (PDI) is a promising approach for the efficient killing of pathogenic microbes. In this study, the photodynamic effect of sulfonated polystyrene nanoparticles with encapsulated hydrophobic 5,10,15,20-tetraphenylporphyrin (TPP-NP) photosensitizers on Gram-positive (including multi-resistant) and Gram-negative bacterial strains was investigated. The cell viability was determined by the colony forming unit method. The results showed no dark cytotoxicity but high phototoxicity within the tested conditions. Gram-positive bacteria were more sensitive to TPP-NPs than Gram-negative bacteria. Atomic force microscopy was used to detect changes in the morphological properties of bacteria before and after the PDI treatment.
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Tarazanova M, Huppertz T, Kok J, Bachmann H. Altering textural properties of fermented milk by using surface-engineered Lactococcus lactis. Microb Biotechnol 2018; 11:770-780. [PMID: 29745037 PMCID: PMC6011991 DOI: 10.1111/1751-7915.13278] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Revised: 02/20/2018] [Accepted: 03/30/2018] [Indexed: 01/23/2023] Open
Abstract
Lactic acid bacteria are widely used for the fermentation of dairy products. While bacterial acidification rates, proteolytic activity and the production of exopolysaccharides are known to influence textural properties of fermented milk products, little is known about the role of the microbial surface on microbe-matrix interactions in dairy products. To investigate how alterations of the bacterial cell surface affect fermented milk properties, 25 isogenic Lactococcus lactis strains that differed with respect to surface charge, hydrophobicity, cell chaining, cell-clumping, attachment to milk proteins, pili expression and EPS production were used to produce fermented milk. We show that overexpression of pili increases surface hydrophobicity of various strains from 3-19% to 94-99%. A profound effect of different cell surface properties was an altered spatial distribution of the cells in the fermented product. Aggregated cells tightly fill the cavities of the protein matrix, while chaining cells seem to be localized randomly. A positive correlation was found between pili overexpression and viscosity and gel hardness of fermented milk. Gel hardness also positively correlated with clumping of cells in the fermented milk. Viscosity of fermented milk was also higher when it was produced with cells with a chaining phenotype or with cells that overexpress exopolysaccharides. Our results show that alteration of cell surface morphology affects textural parameters of fermented milk and cell localization in the product. This is indicative of a cell surface-dependent potential of bacterial cells as structure elements in fermented foods.
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Affiliation(s)
- Mariya Tarazanova
- NIZO B.V.P.O. Box 206710 BAEdeThe Netherlands
- TiFNP.O. Box 5576700 ANWageningenThe Netherlands
- Molecular GeneticsUniversity of GroningenNijenborgh 79747AGGroningenThe Netherlands
| | - Thom Huppertz
- NIZO B.V.P.O. Box 206710 BAEdeThe Netherlands
- TiFNP.O. Box 5576700 ANWageningenThe Netherlands
- Present address:
FrieslandCampinaStationsplein 43818 LE AmersfoortThe Netherlands
| | - Jan Kok
- TiFNP.O. Box 5576700 ANWageningenThe Netherlands
- Molecular GeneticsUniversity of GroningenNijenborgh 79747AGGroningenThe Netherlands
| | - Herwig Bachmann
- NIZO B.V.P.O. Box 206710 BAEdeThe Netherlands
- TiFNP.O. Box 5576700 ANWageningenThe Netherlands
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Hall AR, Geoghegan M. Polymers and biopolymers at interfaces. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2018; 81:036601. [PMID: 29368695 DOI: 10.1088/1361-6633/aa9e9c] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
This review updates recent progress in the understanding of the behaviour of polymers at surfaces and interfaces, highlighting examples in the areas of wetting, dewetting, crystallization, and 'smart' materials. Recent developments in analysis tools have yielded a large increase in the study of biological systems, and some of these will also be discussed, focussing on areas where surfaces are important. These areas include molecular binding events and protein adsorption as well as the mapping of the surfaces of cells. Important techniques commonly used for the analysis of surfaces and interfaces are discussed separately to aid the understanding of their application.
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Affiliation(s)
- A R Hall
- Department of Physics and Astronomy, University of Sheffield, Hounsfield Road, Sheffield S3 7RH, United Kingdom. Fraunhofer Project Centre for Embedded Bioanalytical Systems, Dublin City University, Glasnevin, Dublin 9, Ireland
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Wang H, Wilksch JJ, Chen L, Tan JWH, Strugnell RA, Gee ML. Influence of Fimbriae on Bacterial Adhesion and Viscoelasticity and Correlations of the Two Properties with Biofilm Formation. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:100-106. [PMID: 27959542 DOI: 10.1021/acs.langmuir.6b03764] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
The surface polymers of bacteria determine the ability of bacteria to adhere to a substrate for colonization, which is an essential step for a variety of microbial processes, such as biofilm formation and biofouling. Capsular polysaccharides and fimbriae are two major components on a bacterial surface, which are critical for mediating cell-surface interactions. Adhesion and viscoelasticity of bacteria are two major physical properties related to bacteria-surface interactions. In this study, we employed atomic force microscopy (AFM) to interrogate how the adhesion work and the viscoelasticity of a bacterial pathogen, Klebsiella pneumoniae, influence biofilm formation. To do this, the wild-type, type 3 fimbriae-deficient, and type 3 fimbriae-overexpressed K. pneumoniae strains have been investigated in an aqueous environment. The results show that the measured adhesion work is positively correlated to biofilm formation; however, the viscoelasticity is not correlated to biofilm formation. This study indicates that AFM-based adhesion measurements of bacteria can be used to evaluate the function of bacterial surface polymers in biofilm formation and to predict the ability of bacterial biofilm formation.
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Affiliation(s)
- Huabin Wang
- Chongqing Key Laboratory of Multi-Scale Manufacturing Technology, Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences , Chongqing 400714, China
- Key Laboratory of Interfacial Physics and Technology, Chinese Academy of Sciences , Shanghai 201800, China
| | | | - Ligang Chen
- Chongqing Key Laboratory of Multi-Scale Manufacturing Technology, Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences , Chongqing 400714, China
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Mechanics of Bacterial Cells and Initial Surface Colonisation. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 915:245-60. [DOI: 10.1007/978-3-319-32189-9_15] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
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Marani MM, Dourado FS, Quelemes PV, de Araujo AR, Perfeito MLG, Barbosa EA, Véras LMC, Coelho ALR, Andrade EB, Eaton P, Longo JPF, Azevedo RB, Delerue-Matos C, Leite JRSA. Characterization and Biological Activities of Ocellatin Peptides from the Skin Secretion of the Frog Leptodactylus pustulatus. JOURNAL OF NATURAL PRODUCTS 2015; 78:1495-1504. [PMID: 26107622 DOI: 10.1021/np500907t] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Eight new peptides were isolated from the skin secretion of the frog Leptodactylus pustulatus and their amino acid sequences determined by de novo sequencing and by cDNA cloning. Structural similarities between them and other antimicrobial peptides from the skin secretion of Leptodactylus genus frogs were found. Ocellatins-PT1 to -PT5 (25 amino acid residues) are amidated at the C-terminus, while ocellatins-PT6 to -PT8 (32 amino acid residues) have free carboxylates. Antimicrobial activity, hemolytic tests, and cytotoxicity against a murine fibroblast cell line were investigated. All peptides, except for ocellatin-PT2, have antimicrobial activity against at least one Gram-negative strain. Ocellatin-PT8 inhibited the growth of Escherichia coli, Staphylococcus aureus, Klebsiella pneumoniae, and Salmonella choleraesuis strains with MICs in the 60-240 μM range. No significant effect was observed in human erythrocytes and in a murine fibroblast cell line after exposure to the peptides at MICs. A comparison between sequences obtained by both direct HPLC-MS de novo sequencing and cDNA cloning demonstrates the secretion of mature peptides derived from a pre-pro-peptide structure.
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Affiliation(s)
- Mariela Mirta Marani
- †CENPAT-CONICET, Centro Nacional Patagónico, Consejo Nacional de Investigaciones Científicas y Técnicas, Puerto Madryn, Chubut, Argentina
| | - Flávio Santos Dourado
- ‡Secretaria de Vigilância em Saúde, Ministério da Saúde, SVS/MS, Brasília, DF, Brazil
| | - Patrick Veras Quelemes
- §Núcleo de Pesquisa em Biodiversidade e Biotecnologia, Biotec, Campus Ministro Reis Velloso, Universidade Federal do Piauí, UFPI, Parnaiba, PI, Brazil
| | - Alyne Rodrigues de Araujo
- §Núcleo de Pesquisa em Biodiversidade e Biotecnologia, Biotec, Campus Ministro Reis Velloso, Universidade Federal do Piauí, UFPI, Parnaiba, PI, Brazil
| | - Márcia Luana Gomes Perfeito
- §Núcleo de Pesquisa em Biodiversidade e Biotecnologia, Biotec, Campus Ministro Reis Velloso, Universidade Federal do Piauí, UFPI, Parnaiba, PI, Brazil
| | - Eder Alves Barbosa
- ⊥Programa de Pós-Graduação em Biologia Molecular, Departamento de Biologia Molecular, Universidade de Brasília, Brasília, DF, Brazil
| | - Leiz Maria Costa Véras
- §Núcleo de Pesquisa em Biodiversidade e Biotecnologia, Biotec, Campus Ministro Reis Velloso, Universidade Federal do Piauí, UFPI, Parnaiba, PI, Brazil
| | - Andreia Luísa Rodrigues Coelho
- §Núcleo de Pesquisa em Biodiversidade e Biotecnologia, Biotec, Campus Ministro Reis Velloso, Universidade Federal do Piauí, UFPI, Parnaiba, PI, Brazil
- ∥REQUIMTE/LAQV, Instituto Superior de Engenharia do Instituto Politécnico do Porto, Porto, Portugal
| | - Etielle Barroso Andrade
- §Núcleo de Pesquisa em Biodiversidade e Biotecnologia, Biotec, Campus Ministro Reis Velloso, Universidade Federal do Piauí, UFPI, Parnaiba, PI, Brazil
- ∇Programa de Pós-Graduação em Biodiversidade e Biotecnologia, BIONORTE, Universidade Federal do Maranhão, UFMA, São Luís, MA, Brazil
| | - Peter Eaton
- ○UCIBIO, REQUIMTE, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, Porto, Portugal
| | - João Paulo Figueiró Longo
- #Department of Genetics and Morphology, Institute of Biological Sciences, Universidade de Brasília, Brasilia, Brazil
| | - Ricardo Bentes Azevedo
- #Department of Genetics and Morphology, Institute of Biological Sciences, Universidade de Brasília, Brasilia, Brazil
| | - Cristina Delerue-Matos
- ∥REQUIMTE/LAQV, Instituto Superior de Engenharia do Instituto Politécnico do Porto, Porto, Portugal
| | - José Roberto S A Leite
- §Núcleo de Pesquisa em Biodiversidade e Biotecnologia, Biotec, Campus Ministro Reis Velloso, Universidade Federal do Piauí, UFPI, Parnaiba, PI, Brazil
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Wang H, Wilksch JJ, Strugnell RA, Gee ML. Role of Capsular Polysaccharides in Biofilm Formation: An AFM Nanomechanics Study. ACS APPLIED MATERIALS & INTERFACES 2015; 7:13007-13. [PMID: 26034816 DOI: 10.1021/acsami.5b03041] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Bacteria form biofilms to facilitate colonization of biotic and abiotic surfaces, and biofilm formation on indwelling medical devices is a common cause of hospital-acquired infection. Although it is well-recognized that the exopolysaccharide capsule is one of the key bacterial components for biofilm formation, the underlying biophysical mechanism is poorly understood. In the present study, nanomechanical measurements of wild type and specific mutants of the pathogen, Klebsiella pneumoniae, were performed in situ using atomic force microscopy (AFM). Theoretical modeling of the mechanical data and static microtiter plate biofilm assays show that the organization of the capsule can influence bacterial adhesion, and thereby biofilm formation. The capsular organization is affected by the presence of type 3 fimbriae. Understanding the biophysical mechanisms for the impact of the structural organization of the bacterial polysaccharide capsule on biofilm formation will aid the development of strategies to prevent biofilm formation.
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Affiliation(s)
- Huabin Wang
- §Chongqing Key Laboratory of Multi-Scale Manufacturing Technology, Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China
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Xiao N, Jiao N, Liu Y. In vivo and in vitro observations of polyhydroxybutyrate granules formed by Dinoroseobacter sp. JL 1447. Int J Biol Macromol 2014; 74:467-75. [PMID: 25498348 DOI: 10.1016/j.ijbiomac.2014.11.045] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2014] [Revised: 11/24/2014] [Accepted: 11/25/2014] [Indexed: 12/01/2022]
Abstract
Polyhydroxybutyrate (PHB) granules formed by a marine aerobic anoxygenic phototrophic bacterial strain Dinoroseobacter sp. JL 1447 were detected using transmission electron microscopy and atomic force microscopy. When Dinoroseobacter sp. JL 1447 was inoculated into a medium with glucose as the sole carbon source, the formation of PHB granules occurred and accumulated with incubation time, reaching their maximum in the stationary phase cultures. PHB granules, formed in the cytoplasm at the cell poles or future cell poles, were remobilized and used by the cells in late stationary complex cultures. When PHB granules formed, cell length elongated from 0.5 to 1.5 μm and spherical protrusions appeared on the cell surface. The French press method was used to break the cells and isolate the PHB granules. The freshly prepared and intact PHB granules were spherical with a soft, smooth outer envelope without visible substructures. Upon treating PHB granules with sodium dodecyl sulfate, the envelope was destroyed and nearly parted from the granules, and uniform, spherical structures with a central pore appeared on the granule surface.
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Affiliation(s)
- Na Xiao
- State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen 361102, China; Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100085, China
| | - Nianzhi Jiao
- State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen 361102, China.
| | - Yongqin Liu
- Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100085, China
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Liu B, Uddin MH, Ng TW, Paterson DL, Velkov T, Li J, Fu J. In situ probing the interior of single bacterial cells at nanometer scale. NANOTECHNOLOGY 2014; 25:415101. [PMID: 25257833 DOI: 10.1088/0957-4484/25/41/415101] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
We report a novel approach to probe the interior of single bacterial cells at nanometre resolution by combining focused ion beam (FIB) and atomic force microscopy (AFM). After removing layers of pre-defined thickness in the order of 100 nm on the target bacterial cells with FIB milling, AFM of different modes can be employed to probe the cellular interior under both ambient and aqueous environments. Our initial investigations focused on the surface topology induced by FIB milling and the hydration effects on AFM measurements, followed by assessment of the sample protocols. With fine-tuning of the process parameters, in situ AFM probing beneath the bacterial cell wall was achieved for the first time. We further demonstrate the proposed method by performing a spatial mapping of intracellular elasticity and chemistry of the multi-drug resistant strain Klebsiella pneumoniae cells prior to and after it was exposed to the 'last-line' antibiotic polymyxin B. Our results revealed increased stiffness occurring in both surface and interior regions of the treated cells, suggesting loss of integrity of the outer membrane from polymyxin treatments. In addition, the hydrophobicity measurement using a functionalized AFM tip was able to highlight the evident hydrophobic portion of the cell such as the regions containing cell membrane. We expect that the proposed FIB-AFM platform will help in gaining deeper insights of bacteria-drug interactions to develop potential strategies for combating multi-drug resistance.
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Diao M, Taran E, Mahler S, Nguyen AV. A concise review of nanoscopic aspects of bioleaching bacteria-mineral interactions. Adv Colloid Interface Sci 2014; 212:45-63. [PMID: 25245273 DOI: 10.1016/j.cis.2014.08.005] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Revised: 08/01/2014] [Accepted: 08/28/2014] [Indexed: 01/17/2023]
Abstract
Bioleaching is a technology for the recovery of metals from minerals by means of microorganisms, which accelerate the oxidative dissolution of the mineral by regenerating ferric ions. Bioleaching processes take place at the interface of bacteria, sulfide mineral and leaching solution. The fundamental forces between a bioleaching bacterium and mineral surface are central to understanding the intricacies of interfacial phenomena, such as bacterial adhesion or detachment from minerals and the mineral dissolution. This review focuses on the current state of knowledge in the colloidal aspect of bacteria-mineral interactions, particularly for bioleaching bacteria. Special consideration is given to the microscopic structure of bacterial cells and the atomic force microscopy technique used in the quantification of fundamental interaction forces at nanoscale.
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Affiliation(s)
- Mengxue Diao
- School of Chemical Engineering, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Elena Taran
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Stephen Mahler
- School of Chemical Engineering, The University of Queensland, Brisbane, Queensland 4072, Australia; Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Anh V Nguyen
- School of Chemical Engineering, The University of Queensland, Brisbane, Queensland 4072, Australia.
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Diao M, Taran E, Mahler SM, Nguyen AV. Comparison and evaluation of immobilization methods for preparing bacterial probes using acidophilic bioleaching bacteria Acidithiobacillus thiooxidans for AFM studies. J Microbiol Methods 2014; 102:12-4. [PMID: 24768743 DOI: 10.1016/j.mimet.2014.04.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2014] [Revised: 04/09/2014] [Accepted: 04/12/2014] [Indexed: 11/27/2022]
Abstract
We evaluated different strategies for constructing bacterial probes for atomic force microscopy studies of bioleaching Acidithiobacillus thiooxidans interacting with pyrite mineral surfaces. Of three available techniques, the bacterial colloidal probe technique is the most reliable and provides a versatile platform for quantifying true interactive forces between bioleaching microorganisms and mineral surfaces.
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Affiliation(s)
- Mengxue Diao
- School of Chemical Engineering, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Elena Taran
- Australian Institute for Bioengineering and Nanotechnology, ANFF-Q, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Stephen M Mahler
- School of Chemical Engineering, The University of Queensland, St Lucia, QLD 4072, Australia; Australian Institute for Bioengineering and Nanotechnology, ANFF-Q, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Anh V Nguyen
- School of Chemical Engineering, The University of Queensland, St Lucia, QLD 4072, Australia.
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13
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Antimicrobial protein rBPI21-induced surface changes on Gram-negative and Gram-positive bacteria. NANOMEDICINE-NANOTECHNOLOGY BIOLOGY AND MEDICINE 2014; 10:543-51. [DOI: 10.1016/j.nano.2013.11.002] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2013] [Revised: 10/17/2013] [Accepted: 11/05/2013] [Indexed: 11/18/2022]
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Lonergan N, Britt L, Sullivan C. Immobilizing live Escherichia coli for AFM studies of surface dynamics. Ultramicroscopy 2014; 137:30-9. [DOI: 10.1016/j.ultramic.2013.10.017] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2013] [Revised: 10/23/2013] [Accepted: 10/25/2013] [Indexed: 11/25/2022]
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Ubbink J. Soft matter approaches to structured foods: from "cook-and-look" to rational food design? Faraday Discuss 2012; 158:9-35; discussion 105-24. [PMID: 23234158 DOI: 10.1039/c2fd20125a] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Developments in soft matter physics are discussed within the context of food structuring. An overview is given of soft matter-based approaches used in food, and a relation is established between soft matter approaches and food technology, food creation, product development and nutrition. Advances in food complexity and food sustainability are discussed from a physical perspective, and the potential for future developments is highlighted.
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Affiliation(s)
- Job Ubbink
- Food Concept & Physical Design "The Mill", Mühleweg 10, CH-4112 Flüh, Switzerland.
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Ribeiro M, Monteiro FJ, Ferraz MP. Infection of orthopedic implants with emphasis on bacterial adhesion process and techniques used in studying bacterial-material interactions. BIOMATTER 2012; 2:176-94. [PMID: 23507884 PMCID: PMC3568104 DOI: 10.4161/biom.22905] [Citation(s) in RCA: 424] [Impact Index Per Article: 35.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Staphylococcus comprises up to two-thirds of all pathogens in orthopedic implant infections and they are the principal causative agents of two major types of infection affecting bone: septic arthritis and osteomyelitis, which involve the inflammatory destruction of joint and bone. Bacterial adhesion is the first and most important step in implant infection. It is a complex process influenced by environmental factors, bacterial properties, material surface properties and by the presence of serum or tissue proteins. Properties of the substrate, such as chemical composition of the material, surface charge, hydrophobicity, surface roughness and the presence of specific proteins at the surface, are all thought to be important in the initial cell attachment process. The biofilm mode of growth of infecting bacteria on an implant surface protects the organisms from the host immune system and antibiotic therapy. The research for novel therapeutic strategies is incited by the emergence of antibiotic-resistant bacteria. This work will provide an overview of the mechanisms and factors involved in bacterial adhesion, the techniques that are currently being used studying bacterial-material interactions as well as provide insight into future directions in the field.
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Affiliation(s)
- Marta Ribeiro
- Instituto de Engenharia Biomédica, Universidade do Porto, Porto, Portugal.
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Trinh MH, Odorico M, Pique ME, Teulon JM, Roberts VA, Ten Eyck LF, Getzoff ED, Parot P, Chen SWW, Pellequer JL. Computational reconstruction of multidomain proteins using atomic force microscopy data. Structure 2012; 20:113-20. [PMID: 22244760 DOI: 10.1016/j.str.2011.10.023] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2011] [Revised: 10/05/2011] [Accepted: 10/10/2011] [Indexed: 01/10/2023]
Abstract
Classical structural biology techniques face a great challenge to determine the structure at the atomic level of large and flexible macromolecules. We present a novel methodology that combines high-resolution AFM topographic images with atomic coordinates of proteins to assemble very large macromolecules or particles. Our method uses a two-step protocol: atomic coordinates of individual domains are docked beneath the molecular surface of the large macromolecule, and then each domain is assembled using a combinatorial search. The protocol was validated on three test cases: a simulated system of antibody structures; and two experimentally based test cases: Tobacco mosaic virus, a rod-shaped virus; and Aquaporin Z, a bacterial membrane protein. We have shown that AFM-intermediate resolution topography and partial surface data are useful constraints for building macromolecular assemblies. The protocol is applicable to multicomponent structures connected in the polypeptide chain or as disjoint molecules. The approach effectively increases the resolution of AFM beyond topographical information down to atomic-detail structures.
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Affiliation(s)
- Minh-Hieu Trinh
- CEA, iBEB, Department of Biochemistry and Nuclear Toxicology, F-30207 Bagnols sur Cèze, France
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Epifluorescence and atomic force microscopy: Two innovative applications for studying phage–host interactions in Lactobacillus helveticus. J Microbiol Methods 2012; 88:41-6. [DOI: 10.1016/j.mimet.2011.10.006] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2011] [Revised: 10/05/2011] [Accepted: 10/05/2011] [Indexed: 11/24/2022]
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Kweon H, Yiacoumi S, Tsouris C. Friction and adhesion forces of Bacillus thuringiensis spores on planar surfaces in atmospheric systems. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2011; 27:14975-14981. [PMID: 22059743 DOI: 10.1021/la203575q] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The kinetic friction force and the adhesion force of Bacillus thuringiensis spores on planar surfaces in atmospheric systems were studied using atomic force microscopy. The influence of relative humidity (RH) on these forces varied for different surface properties including hydrophobicity, roughness, and surface charge. The friction force of the spore was greater on a rougher surface than on mica, which is atomically flat. As RH increases, the friction force of the spores decreases on mica whereas it increases on rough surfaces. The influence of RH on the interaction forces between hydrophobic surfaces is not as strong as for hydrophilic surfaces. The friction force of the spore is linear to the sum of the adhesion force and normal load on the hydrophobic surface. The poorly defined surface structure of the spore and the adsorption of contaminants from the surrounding atmosphere are believed to cause a discrepancy between the calculated and measured adhesion forces.
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Affiliation(s)
- Hyojin Kweon
- Georgia Institute of Technology, Atlanta, Georgia 30332-0373, USA
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20
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Phelan VV, Liu WT, Pogliano K, Dorrestein PC. Microbial metabolic exchange--the chemotype-to-phenotype link. Nat Chem Biol 2011; 8:26-35. [PMID: 22173357 DOI: 10.1038/nchembio.739] [Citation(s) in RCA: 151] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The function of microbial interactions is to enable microorganisms to survive by establishing a homeostasis between microbial neighbors and local environments. A microorganism can respond to environmental stimuli using metabolic exchange-the transfer of molecular factors, including small molecules and proteins. Microbial interactions not only influence the survival of the microbes but also have roles in morphological and developmental processes of the organisms themselves and their neighbors. This, in turn, shapes the entire habitat of these organisms. Here we highlight our current understanding of metabolic exchange as well as the emergence of new technologies that are allowing us to eavesdrop on microbial conversations comprising dozens to hundreds of secreted metabolites that control the behavior, survival and differentiation of members of the community. The goal of the rapidly advancing field studying multifactorial metabolic exchange is to devise a microbial 'Rosetta stone' in order to understand the language by which microbial interactions are negotiated and, ultimately, to control the outcome of these conversations.
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Affiliation(s)
- Vanessa V Phelan
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, California, USA
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21
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Interaction forces drive the environmental transmission of pathogenic protozoa. Appl Environ Microbiol 2011; 78:905-12. [PMID: 22156429 DOI: 10.1128/aem.06488-11] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The protozoan parasites Giardia duodenalis, Cryptosporidium spp., and Toxoplasma gondii are pathogens that are resistant to a number of environmental factors and pose significant risks to public health worldwide. Their environmental transmission is closely governed by the physicochemical properties of their cysts (Giardia) and oocysts (Cryptosporidium and Toxoplasma), allowing their transport, retention, and survival for months in water, soil, vegetables, and mollusks, which are the main reservoirs for human infection. Importantly, the cyst/oocyst wall plays a key role in that regard by exhibiting a complex polymeric coverage that determines the charge and hydrophobic characteristics of parasites' surfaces. Interaction forces between parasites and other environmental particles may be, in a first approximation, evaluated following the Derjaguin-Landau-Verwey-Overbeek (DLVO) theory of colloidal stability. However, due to the molecular topography and nano- to microstructure of the cyst/oocyst surface, non-DVLO hydrophobic forces together with additional steric attractive and/or repulsive forces may play a pivotal role in controlling the parasite behavior when the organism is subjected to various external conditions. Here, we review several parameters that enhance or hinder the adhesion of parasites to other particles and surfaces and address the role of fast-emerging techniques for mapping the cyst/oocyst surface, e.g., by measuring its topology and the generated interaction forces at the nano- to microscale. We discuss why characterizing these interactions could be a crucial step for managing the environmental matrices at risk of microbial pollution.
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22
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Chen P, Jiang L, Han D. In situ imaging of multiphase bio-interfaces at the micro-/nanoscale. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2011; 7:2825-2835. [PMID: 21932246 DOI: 10.1002/smll.201100039] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2011] [Revised: 04/04/2011] [Indexed: 05/31/2023]
Abstract
The multiphase bio-interfacial system constituted by biological surfaces and their surrounding environment is usually considered to be an essential clue for exploring the mysterious relationship between surface architecture and function. As a visualizing method to understand these systems, in situ imaging of multiphase interfaces (e.g., air/liquid/solid and oil/water/solid systems) at the micro-/nanoscale, still remains a huge challenge, as a result of their heterogeneity and complexity. Here, recent progress on real-space micro-/nanoscale imaging of multiphase bio-interfacial systems is reviewed; this includes several techniques and imaging results on bio-interfaces, such as the lotus leaf, fish scale, living cell's surface, and fresh tissue surface. The results evidently show that interfacial structures have a significant impact on the state of the microscopic multiphase interface, further influencing specific functions. Based on this research, technical innovations, some more complicated multiphase interface systems, and structure-function coupling mechanism are proposed.
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Affiliation(s)
- Peipei Chen
- National Center for Nanoscience and Technology, Beijing, People's Republic of China
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23
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Wilk L, Strauss M, Rudolf M, Nicolaisen K, Flores E, Kühlbrandt W, Schleiff E. Outer membrane continuity and septosome formation between vegetative cells in the filaments of Anabaena sp. PCC 7120. Cell Microbiol 2011; 13:1744-54. [DOI: 10.1111/j.1462-5822.2011.01655.x] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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24
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Francius G, Polyakov P, Merlin J, Abe Y, Ghigo JM, Merlin C, Beloin C, Duval JFL. Bacterial surface appendages strongly impact nanomechanical and electrokinetic properties of Escherichia coli cells subjected to osmotic stress. PLoS One 2011; 6:e20066. [PMID: 21655293 PMCID: PMC3105017 DOI: 10.1371/journal.pone.0020066] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2011] [Accepted: 04/17/2011] [Indexed: 11/19/2022] Open
Abstract
The physicochemical properties and dynamics of bacterial envelope, play a major role in bacterial activity. In this study, the morphological, nanomechanical and electrohydrodynamic properties of Escherichia coli K-12 mutant cells were thoroughly investigated as a function of bulk medium ionic strength using atomic force microscopy (AFM) and electrokinetics (electrophoresis). Bacteria were differing according to genetic alterations controlling the production of different surface appendages (short and rigid Ag43 adhesins, longer and more flexible type 1 fimbriae and F pilus). From the analysis of the spatially resolved force curves, it is shown that cells elasticity and turgor pressure are not only depending on bulk salt concentration but also on the presence/absence and nature of surface appendage. In 1 mM KNO(3), cells without appendages or cells surrounded by Ag43 exhibit large Young moduli and turgor pressures (∼700-900 kPa and ∼100-300 kPa respectively). Under similar ionic strength condition, a dramatic ∼50% to ∼70% decrease of these nanomechanical parameters was evidenced for cells with appendages. Qualitatively, such dependence of nanomechanical behavior on surface organization remains when increasing medium salt content to 100 mM, even though, quantitatively, differences are marked to a much smaller extent. Additionally, for a given surface appendage, the magnitude of the nanomechanical parameters decreases significantly when increasing bulk salt concentration. This effect is ascribed to a bacterial exoosmotic water loss resulting in a combined contraction of bacterial cytoplasm together with an electrostatically-driven shrinkage of the surface appendages. The former process is demonstrated upon AFM analysis, while the latter, inaccessible upon AFM imaging, is inferred from electrophoretic data interpreted according to advanced soft particle electrokinetic theory. Altogether, AFM and electrokinetic results clearly demonstrate the intimate relationship between structure/flexibility and charge of bacterial envelope and propensity of bacterium and surface appendages to contract under hypertonic conditions.
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Affiliation(s)
- Grégory Francius
- Laboratoire de Chimie Physique et Microbiologie pour l'Environnement, Nancy Université, CNRS UMR7564, Villers-lès-Nancy, France
| | - Pavel Polyakov
- Laboratoire de Chimie Physique et Microbiologie pour l'Environnement, Nancy Université, CNRS UMR7564, Villers-lès-Nancy, France
| | - Jenny Merlin
- Laboratoire Environnement et Minéralurgie, Nancy Université, CNRS UMR7569, Vandoeuvre-lès-Nancy, France
| | - Yumiko Abe
- Laboratoire de Chimie Physique et Microbiologie pour l'Environnement, Nancy Université, CNRS UMR7564, Villers-lès-Nancy, France
| | - Jean-Marc Ghigo
- Institut Pasteur, Unité de Génétique des Biofilms, Paris, France
- CNRS URA 2172, Paris, France
| | - Christophe Merlin
- Laboratoire de Chimie Physique et Microbiologie pour l'Environnement, Nancy Université, CNRS UMR7564, Villers-lès-Nancy, France
| | - Christophe Beloin
- Institut Pasteur, Unité de Génétique des Biofilms, Paris, France
- CNRS URA 2172, Paris, France
| | - Jérôme F. L. Duval
- Laboratoire Environnement et Minéralurgie, Nancy Université, CNRS UMR7569, Vandoeuvre-lès-Nancy, France
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25
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Acid tolerant mutants of Bifidobacterium animalis subsp. lactis with improved stability in fruit juice. Lebensm Wiss Technol 2011. [DOI: 10.1016/j.lwt.2010.11.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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26
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Jung SH, Park D, Park JH, Kim YM, Ha KS. Molecular imaging of membrane proteins and microfilaments using atomic force microscopy. Exp Mol Med 2010; 42:597-605. [PMID: 20689364 PMCID: PMC2947017 DOI: 10.3858/emm.2010.42.9.064] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/05/2010] [Indexed: 11/04/2022] Open
Abstract
Atomic force microscopy (AFM) is an emerging technique for a variety of uses involving the analysis of cells. AFM is widely applied to obtain information about both cellular structural and subcellular events. In particular, a variety of investigations into membrane proteins and microfilaments were performed with AFM. Here, we introduce applications of AFM to molecular imaging of membrane proteins, and various approaches for observation and identification of intracellular microfilaments at the molecular level. These approaches can contribute to many applications of AFM in cell imaging.
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Affiliation(s)
- Se-Hui Jung
- Department of Molecular and Cellular Biochemistry, Kangwon National University School of Medicine, Chuncheon 200-701, Korea
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27
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Alves CS, Melo MN, Franquelim HG, Ferre R, Planas M, Feliu L, Bardají E, Kowalczyk W, Andreu D, Santos NC, Fernandes MX, Castanho MARB. Escherichia coli cell surface perturbation and disruption induced by antimicrobial peptides BP100 and pepR. J Biol Chem 2010; 285:27536-44. [PMID: 20566635 DOI: 10.1074/jbc.m110.130955] [Citation(s) in RCA: 173] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The potential of antimicrobial peptides (AMPs) as an alternative to conventional therapies is well recognized. Insights into the biological and biophysical properties of AMPs are thus key to understanding their mode of action. In this study, the mechanisms adopted by two AMPs in disrupting the gram-negative Escherichia coli bacterial envelope were explored. BP100 is a short cecropin A-melittin hybrid peptide known to inhibit the growth of phytopathogenic gram-negative bacteria. pepR, on the other hand, is a novel AMP derived from the dengue virus capsid protein. Both BP100 and pepR were found to inhibit the growth of E. coli at micromolar concentrations. Zeta potential measurements of E. coli incubated with increasing peptide concentrations allowed for the establishment of a correlation between the minimal inhibitory concentration (MIC) of each AMP and membrane surface charge neutralization. While a neutralization-mediated killing mechanism adopted by either AMP is not necessarily implied, the hypothesis that surface neutralization occurs close to MIC values was confirmed. Atomic force microscopy (AFM) was then employed to visualize the structural effect of the interaction of each AMP with the E. coli cell envelope. At their MICs, BP100 and pepR progressively destroyed the bacterial envelope, with extensive damage already occurring 2 h after peptide addition to the bacteria. A similar effect was observed for each AMP in the concentration-dependent studies. At peptide concentrations below MIC values, only minor disruptions of the bacterial surface occurred.
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Affiliation(s)
- Carla S Alves
- Centro de Química da Madeira, Universidade da Madeira, Campus Universitário da Penteada, 9000-390 Funchal, Portugal
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28
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Abstract
This review outlines progress in atomic force infrared microscopy, reviewing the methodology and its application in nanoscale infrared absorption imaging of both biological and functional materials, including an outline of where this emerging method has been applied to image cellular systems in aqueous environments.
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Affiliation(s)
- James H Rice
- School of Physics, University College Dublin, Belfield, Dublin, Ireland.
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29
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Deepika G, Charalampopoulos D. Surface and adhesion properties of lactobacilli. ADVANCES IN APPLIED MICROBIOLOGY 2010; 70:127-52. [PMID: 20359456 DOI: 10.1016/s0065-2164(10)70004-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The surface properties of lactobacilli are of significant technological importance as they determine the interaction of the bacterial cells with the gastrointestinal mucosa, and therefore influence their location in the gut and their functionality. Studying the surface of the bacteria is critical for understanding the adhesion process better. This review compiles the knowledge from studies on the characterization Lactobacillus surfaces and evaluates the potential relationship between the cells' physicochemical characteristics and their adhesive abilities. It also discusses the effect that the production processes, such as fermentation and drying, can exert on the surface properties and adhesion abilities of lactobacilli.
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Affiliation(s)
- G Deepika
- Department of Food and Nutritional Sciences, The University of Reading, Reading RG6 6AP, UK
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30
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Dorobantu LS, Gray MR. Application of atomic force microscopy in bacterial research. SCANNING 2010; 32:74-96. [PMID: 20695026 DOI: 10.1002/sca.20177] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
The atomic force microscope (AFM) has evolved from an imaging device into a multifunctional and powerful toolkit for probing the nanostructures and surface components on the exterior of bacterial cells. Currently, the area of application spans a broad range of interesting fields from materials sciences, in which AFM has been used to deposit patterns of thiol-functionalized molecules onto gold substrates, to biological sciences, in which AFM has been employed to study the undesirable bacterial adhesion to implants and catheters or the essential bacterial adhesion to contaminated soil or aquifers. The unique attribute of AFM is the ability to image bacterial surface features, to measure interaction forces of functionalized probes with these features, and to manipulate these features, for example, by measuring elongation forces under physiological conditions and at high lateral resolution (<1 A). The first imaging studies showed the morphology of various biomolecules followed by rapid progress in visualizing whole bacterial cells. The AFM technique gradually developed into a lab-on-a-tip allowing more quantitative analysis of bacterial samples in aqueous liquids and non-contact modes. Recently, force spectroscopy modes, such as chemical force microscopy, single-cell force spectroscopy, and single-molecule force spectroscopy, have been used to map the spatial arrangement of chemical groups and electrical charges on bacterial surfaces, to measure cell-cell interactions, and to stretch biomolecules. In this review, we present the fascinating options offered by the rapid advances in AFM with emphasizes on bacterial research and provide a background for the exciting research articles to follow.
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Affiliation(s)
- Loredana S Dorobantu
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta, Canada.
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31
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Chung E, Kweon H, Yiacoumi S, Lee I, Joy DC, Palumbo AV, Tsouris C. Adhesion of spores of Bacillus thuringiensis on a planar surface. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2010; 44:290-296. [PMID: 19928904 DOI: 10.1021/es902070b] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Adhesion of spores of Bacillus thuringiensis (Bt) and spherical silica particles on surfaces was experimentally and theoretically investigated in this study. Topography analysis via atomic force microscopy (AFM) and electron microscopy indicates that Bt spores are rod shaped, approximately 1.3 mum in length and approximately 0.8 mum in diameter. The adhesion force of Bt spores and silica particles on gold-coated glass was measured at various relative humidity (RH) levels by AFM. It was expected that the adhesion force would vary with RH because the individual force components contributing to the adhesion force depend on RH. The adhesion force between a particle and a planar surface in atmospheric environments was modeled as the contribution of three major force components: capillary, van der Waals, and electrostatic interaction forces. Adhesion force measurements for Bt spore (silica particle) and the gold surface system were comparable with calculations. Modeling results show that there is a critical RH value, which depends on the hydrophobicity of the materials involved, below which the water meniscus does not form and the contribution of the capillary force is zero. As RH increases, the van der Waals force decreases while the capillary force increases to a maximum value.
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Affiliation(s)
- Eunhyea Chung
- Georgia Institute of Technology, Atlanta, Georgia 30332-0373, USA
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32
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Park BJ, Haines T, Abu-Lail NI. A correlation between the virulence and the adhesion of Listeria monocytogenes to silicon nitride: An atomic force microscopy study. Colloids Surf B Biointerfaces 2009; 73:237-43. [DOI: 10.1016/j.colsurfb.2009.05.027] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2009] [Revised: 05/09/2009] [Accepted: 05/25/2009] [Indexed: 12/31/2022]
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33
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Quantification of microparticle coating quality by confocal laser scanning microscopy (CLSM). Eur J Pharm Biopharm 2009; 73:179-86. [DOI: 10.1016/j.ejpb.2009.04.007] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2008] [Revised: 04/15/2009] [Accepted: 04/20/2009] [Indexed: 11/20/2022]
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34
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Abstract
In this review, I describe the biological applications of the atomic force microscope (AFM). The historical background and the development of the microscope are described. The AFM can operate in many different modes relevant to biological systems including topography, chemical analysis, and forces relevant at the biological length scale (single cell to DNA dimensions and pico to nano Newton forces). A limited number of examples from the literature are described to illustrate some of the many capabilities of this microscope. The aim is to give an introduction of the technique to the inexperienced in this rapidly growing field.
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Affiliation(s)
- N Gadegaard
- Centre for Cell Engineering, University of Glasgow, Glasgow, G12 8LT, United Kingdom.
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35
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Sahu K, Bansal H, Mukherjee C, Sharma M, Gupta PK. Atomic force microscopic study on morphological alterations induced by photodynamic action of Toluidine Blue O in Staphylococcus aureus and Escherichia coli. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2009; 96:9-16. [DOI: 10.1016/j.jphotobiol.2009.03.008] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2008] [Revised: 02/06/2009] [Accepted: 03/25/2009] [Indexed: 11/29/2022]
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36
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Francius G, Alsteens D, Dupres V, Lebeer S, De Keersmaecker S, Vanderleyden J, Gruber HJ, Dufrêne YF. Stretching polysaccharides on live cells using single molecule force spectroscopy. Nat Protoc 2009; 4:939-46. [DOI: 10.1038/nprot.2009.65] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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37
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Nanoscale structural and mechanical properties of nontypeable Haemophilus influenzae biofilms. J Bacteriol 2009; 191:2512-20. [PMID: 19218382 DOI: 10.1128/jb.01596-08] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Nontypeable Haemophilus influenzae (NTHI) bacteria are commensals in the human nasopharynx, as well as pathogens associated with a spectrum of acute and chronic infections. Two important factors that influence NTHI pathogenicity are their ability to adhere to human tissue and their ability to form biofilms. Extracellular polymeric substances (EPS) and bacterial appendages such as pili critically influence cell adhesion and intercellular cohesion during biofilm formation. Structural components in the outer cell membrane, such as lipopolysaccharides, also play a fundamental role in infection of the host organism. In spite of their importance, these pathogenic factors are not yet well characterized at the nanoscale. Here, atomic force microscopy (AFM) was used in aqueous environments to visualize structural details, including probable Hif-type pili, of live NTHI bacteria at the early stages of biofilm formation. Using single-molecule AFM-based spectroscopy, the molecular elasticities of lipooligosaccharides present on NTHI cell surfaces were analyzed and compared between two strains (PittEE and PittGG) with very different pathogenicity profiles. Furthermore, the stiffness of single cells of both strains was measured and subsequently their turgor pressure was estimated.
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38
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D'Agostino DP, Olson JE, Dean JB. Acute hyperoxia increases lipid peroxidation and induces plasma membrane blebbing in human U87 glioblastoma cells. Neuroscience 2009; 159:1011-22. [PMID: 19356685 DOI: 10.1016/j.neuroscience.2009.01.062] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2008] [Revised: 01/26/2009] [Accepted: 01/27/2009] [Indexed: 11/28/2022]
Abstract
Atomic force microscopy (AFM), malondialdehyde (MDA) assays, and amperometric measurements of extracellular hydrogen peroxide (H(2)O(2)) were used to test the hypothesis that graded hyperoxia induces measurable nanoscopic changes in membrane ultrastructure and membrane lipid peroxidation (MLP) in cultured U87 human glioma cells. U87 cells were exposed to 0.20 atmospheres absolute (ATA) O(2), normobaric hyperoxia (0.95 ATA O(2)) or hyperbaric hyperoxia (HBO(2), 3.25 ATA O(2)) for 60 min. H(2)O(2) (0.2 or 2 mM; 60 min) was used as a positive control for MLP. Cells were fixed with 2% glutaraldehyde immediately after treatment and scanned with AFM in air or fluid. Surface topography revealed ultrastructural changes such as membrane blebbing in cells treated with hyperoxia and H(2)O(2). Average membrane roughness (R(a)) of individual cells from each group (n=35 to 45 cells/group) was quantified to assess ultrastructural changes from oxidative stress. The R(a) of the plasma membrane was 34+/-3, 57+/-3 and 63+/-5 nm in 0.20 ATA O(2), 0.95 ATA O(2) and HBO(2), respectively. R(a) was 56+/-7 and 138+/-14 nm in 0.2 and 2 mM H(2)O(2). Similarly, levels of MDA were significantly elevated in cultures treated with hyperoxia and H(2)O(2) and correlated with O(2)-induced membrane blebbing (r(2)=0.93). Coapplication of antioxidant, Trolox-C (150 microM), significantly reduced membrane R(a) and MDA levels during hyperoxia. Hyperoxia-induced H(2)O(2) production increased 189%+/-5% (0.95 ATA O(2)) and 236%+/-5% (4 ATA O(2)) above control (0.20 ATA O(2)). We conclude that MLP and membrane blebbing increase with increasing O(2) concentration. We hypothesize that membrane blebbing is an ultrastructural correlate of MLP resulting from hyperoxia. Furthermore, AFM is a powerful technique for resolving nanoscopic changes in the plasma membrane that result from oxidative damage.
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Affiliation(s)
- D P D'Agostino
- Department of Molecular Pharmacology and Physiology, Hyperbaric Biomedical Research Laboratory, College of Medicine, MDC 8, University of South Florida, 12901 Bruce B. Downs Boulevard, Tampa, FL 33612, USA
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39
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Mitchell G, Lamontagne CA, Brouillette E, Grondin G, Talbot BG, Grandbois M, Malouin F. Staphylococcus aureus SigB activity promotes a strong fibronectin-bacterium interaction which may sustain host tissue colonization by small-colony variants isolated from cystic fibrosis patients. Mol Microbiol 2009; 70:1540-55. [PMID: 19007412 DOI: 10.1111/j.1365-2958.2008.06511.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Genes encoding cell-surface proteins regulated by SigB are stably expressed in Staphylococcus aureus small-colony variants (SCVs) isolated from cystic fibrosis (CF) patients. Our hypothesis is that CF-isolated SCVs are locked into a colonization state by sustaining the expression of adhesins such as fibronectin-binding proteins (FnBPs) throughout growth. Force spectroscopy was used to study the fibronectin-FnBPs interaction among strains varying for their SigB activity. The fibronectin-FnBPs interaction was described by a strength of 1000+/-400 pN (pulling rate of 2 microm s(-1)), an energetic barrier width of 0.6+/-0.1 A and an off-rate below 2 x 10(-4) s(-1). A CF-isolated SCV highly expressed fnbA throughout growth and showed a sustained capacity to bind fibronectin, whereas a prototypic strain showed a reduced frequency of fibronectin-binding during the stationary growth phase when its fnbA gene was down-regulated. Reduced expression of fnbA was observed in sigB mutants, which was associated with an overall decrease adhesion to fibronectin. These results suggest that the fibronectin-FnBPs interaction plays a role in the formation of a mechanically resistant adhesion of S. aureus to host tissues and supports the hypothesis that CF-isolated SCVs are locked into a colonization state as a result of a sustained SigB activity.
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Affiliation(s)
- Gabriel Mitchell
- Centre d'Etude et de Valorisation de la Diversité Microbienne, Département de biologie, Faculté des sciences, Université de Sherbrooke, Sherbrooke, QC, J1K 2R1, Canada
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40
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Alsteens D, Dupres V, Mc Evoy K, Wildling L, Gruber HJ, Dufrêne YF. Structure, cell wall elasticity and polysaccharide properties of living yeast cells, as probed by AFM. NANOTECHNOLOGY 2008; 19:384005. [PMID: 21832565 DOI: 10.1088/0957-4484/19/38/384005] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Although the chemical composition of yeast cell walls is known, the organization, assembly, and interactions of the various macromolecules remain poorly understood. Here, we used in situ atomic force microscopy (AFM) in three different modes to probe the ultrastructure, cell wall elasticity and polymer properties of two brewing yeast strains, i.e. Saccharomyces carlsbergensis and S. cerevisiae. Topographic images of the two strains revealed smooth and homogeneous cell surfaces, and the presence of circular bud scars on dividing cells. Nanomechanical measurements demonstrated that the cell wall elasticity of S. carlsbergensis is homogeneous. By contrast, the bud scar of S. cerevisiae was found to be stiffer than the cell wall, presumably due to the accumulation of chitin. Notably, single molecule force spectroscopy with lectin-modified tips revealed major differences in polysaccharide properties of the two strains. Polysaccharides were clearly more extended on S. cerevisiae, suggesting that not only oligosaccharides, but also polypeptide chains of the mannoproteins were stretched. Consistent with earlier cell surface analyses, these findings may explain the very different aggregation properties of the two organisms. This study demonstrates the power of using multiple complementary AFM modalities for probing the organization and interactions of the various macromolecules of microbial cell walls.
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Affiliation(s)
- David Alsteens
- Unité de Chimie des Interfaces, Université Catholique de Louvain, Croix du Sud 2/18, B-1348 Louvain-la-Neuve, Belgium
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Francius G, Lebeer S, Alsteens D, Wildling L, Gruber HJ, Hols P, De Keersmaecker S, Vanderleyden J, Dufrêne YF. Detection, localization, and conformational analysis of single polysaccharide molecules on live bacteria. ACS NANO 2008; 2:1921-1929. [PMID: 19206433 DOI: 10.1021/nn800341b] [Citation(s) in RCA: 106] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The nanoscale exploration of microbes using atomic force microscopy (AFM) is an exciting, rapidly evolving research field. Here, we show that single-molecule force spectroscopy is a valuable tool for the localization and conformational analysis of individual polysaccharides on live bacteria. We focus on the clinically important probiotic bacterium Lactobacillus rhamnosus GG, demonstrating the power of AFM to reveal the coexistence of polysaccharide chains of different nature on the cell surface. Applicable to a wide variety of cells, this single molecule method offers exciting prospects for analyzing the heterogeneity and diversity of macromolecules constituting cell membranes and cell walls.
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Affiliation(s)
- Grégory Francius
- Unite de Chimie des Interfaces, Universite Catholique de Louvain, Croix du Sud 2/18, B-1348 Louvain-la-Neuve, Belgium
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42
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Abstract
Over the past years, atomic force microscopy (AFM) has emerged as a powerful tool for imaging the surface of microbial cells with nanometer resolution, and under physiological conditions. Moreover, chemical force microscopy (CFM) and single-molecule force spectroscopy have enabled researchers to map chemical groups and receptors on cell surfaces, providing valuable insight into their structure-function relationships. Here, we present protocols for analyzing spores of the pathogen Aspergillus fumigatus using real-time AFM imaging and CFM. We emphasize the use of porous polymer membranes for immobilizing single live cells, and the modification of gold-coated tips with alkanethiols for CFM measurements. We also discuss recording conditions and data interpretation, and provide recommendations for reliable experiments. For well-trained AFM users, the entire protocol can be completed in 2-3 d.
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Ubbink J, Burbidge A, Mezzenga R. Food structure and functionality: a soft matter perspective. SOFT MATTER 2008; 4:1569-1581. [PMID: 32907147 DOI: 10.1039/b802183j] [Citation(s) in RCA: 126] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The structure and functionality of foods are described from the perspective of recent advances in soft condensed matter physics. An overview is given of the structure and properties of food materials in terms of the physically relevant length scales. Recent developments in the understanding of the physics of gels, micelles, liquid crystals, biopolymer complexes and amorphous carbohydrates are presented.
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Affiliation(s)
- Job Ubbink
- Nestlé Research Center, CH-1000 Lausanne 26, Switzerland.
| | - Adam Burbidge
- Nestlé Research Center, CH-1000 Lausanne 26, Switzerland. and School of Engineering, University of Wales Singleton Park, Swansea, United KingdomSA2 8PP.
| | - Raffaele Mezzenga
- Nestlé Research Center, CH-1000 Lausanne 26, Switzerland. and University of Fribourg and Fribourg Center for Nanomaterials, CH-1700, Fribourg, Switzerland.
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Use of atomic force microscopy and transmission electron microscopy for correlative studies of bacterial capsules. Appl Environ Microbiol 2008; 74:5457-65. [PMID: 18606791 DOI: 10.1128/aem.02075-07] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Bacteria can possess an outermost assembly of polysaccharide molecules, a capsule, which is attached to their cell wall. We have used two complementary, high-resolution microscopy techniques, atomic force microscopy (AFM) and transmission electron microscopy (TEM), to study bacterial capsules of four different gram-negative bacterial strains: Escherichia coli K30, Pseudomonas aeruginosa FRD1, Shewanella oneidensis MR-4, and Geobacter sulfurreducens PCA. TEM analysis of bacterial cells using different preparative techniques (whole-cell mounts, conventional embeddings, and freeze-substitution) revealed capsules for some but not all of the strains. In contrast, the use of AFM allowed the unambiguous identification of the presence of capsules on all strains used in the present study, including those that were shown by TEM to be not encapsulated. In addition, the use of AFM phase imaging allowed the visualization of the bacterial cell within the capsule, with a depth sensitivity that decreased with increasing tapping frequency.
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Sum C, Mohanty S, Gupta PK, Kishen A. Influence of endodontic chemical treatment on Enterococcus faecalis adherence to collagen studied with laser scanning confocal microscopy and optical tweezers: a preliminary study. JOURNAL OF BIOMEDICAL OPTICS 2008; 13:044017. [PMID: 19021345 DOI: 10.1117/1.2957972] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Failure of endodontic treatment is commonly associated with the presence of Enterococcus faecalis. Studies have highlighted that E. faecalis can form a calcified biofilm in tough environmental conditions, such as within root canals. The aims of this study were to investigate the effects of chemicals used in root-canal disinfection on the adherence of E. faecalis to collagen, as well as to estimate the force of adhesion between E. faecalis and collagen after such treatment. The number of adhering bacteria after chemical treatment was determined using confocal laser scanning microscopy-based adherence assay. It was found that the calcium hydroxide-treated group had a statistically significant (p=0.05) increase in the population of bacteria adhering. The adhesion force between bacteria and collagen of the treatment group with the highest number of bacteria adhering was determined by using optical tweezers (1064 nm) and Equipartitition theorem-based stiffness measurements. The presence of calcium hydroxide was found to significantly increase the bacterium-collagen adhesion force. These experiments highlighted the potential advantage of using optical tweezers to study bacteria-substrate interactions. The findings from the present study suggests that the presence of calcium hydroxide increased the adhesion force and adherence of E. faecalis to type-I collagen.
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Affiliation(s)
- CheePeng Sum
- National University of Singapore, Department of Restorative Dentistry, Faculty of Dentistry, 5 Lower Kent Ridge Rd., Singapore 119074
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46
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High spatial resolution surface imaging and analysis of fungal cells using SEM and AFM. Micron 2008; 39:349-61. [DOI: 10.1016/j.micron.2007.10.023] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2007] [Revised: 10/17/2007] [Accepted: 10/18/2007] [Indexed: 11/22/2022]
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Dorobantu LS, Bhattacharjee S, Foght JM, Gray MR. Atomic force microscopy measurement of heterogeneity in bacterial surface hydrophobicity. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2008; 24:4944-4951. [PMID: 18355095 DOI: 10.1021/la7035295] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The structure and physicochemical properties of microbial surfaces at the molecular level determine their adhesion to surfaces and interfaces. Here, we report the use of atomic force microscopy (AFM) to explore the morphology of soft, living cells in aqueous buffer, to map bacterial surface heterogeneities, and to directly correlate the results in the AFM force-distance curves to the macroscopic properties of the microbial surfaces. The surfaces of two bacterial species, Acinetobacter venetianus RAG-1 and Rhodococcus erythropolis 20S-E1-c, showing different macroscopic surface hydrophobicity were probed with chemically functionalized AFM tips, terminating in hydrophobic and hydrophilic groups. All force measurements were obtained in contact mode and made on a location of the bacterium selected from the alternating current mode image. AFM imaging revealed morphological details of the microbial-surface ultrastructures with about 20 nm resolution. The heterogeneous surface morphology was directly correlated with differences in adhesion forces as revealed by retraction force curves and also with the presence of external structures, either pili or capsules, as confirmed by transmission electron microscopy. The AFM force curves for both bacterial species showed differences in the interactions of extracellular structures with hydrophilic and hydrophobic tips. A. venetianus RAG-1 showed an irregular pattern with multiple adhesion peaks suggesting the presence of biopolymers with different lengths on its surface. R. erythropolis 20S-E1-c exhibited long-range attraction forces and single rupture events suggesting a more hydrophobic and smoother surface. The adhesion force measurements indicated a patchy surface distribution of interaction forces for both bacterial species, with the highest forces grouped at one pole of the cell for R. erythropolis 20S-E1-c and a random distribution of adhesion forces in the case of A. venetianus RAG-1. The magnitude of the adhesion forces was proportional to the three-phase contact angle between hexadecane and water on the bacterial surfaces.
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Affiliation(s)
- Loredana S Dorobantu
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 2G6, Canada
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Bassas M, Diaz J, Rodriguez E, Espuny MJ, Prieto MJ, Manresa A. Microscopic examination in vivo and in vitro of natural and cross-linked polyunsaturated mclPHA. Appl Microbiol Biotechnol 2008; 78:587-96. [PMID: 18224316 DOI: 10.1007/s00253-008-1350-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2007] [Revised: 01/03/2008] [Accepted: 01/03/2008] [Indexed: 11/27/2022]
Abstract
Pseudomonas aeruginosa 42A2 produces a polyunsaturated polyhydroxyalkanoates (PHA-L) when grown on linseed oil as a substrate. Its high unsaturation content (36.5%) provides highly reactive PHA-L, generating a cross-linked biopolymer after ultraviolet (UV) irradiation. Both PHAs (PHA-L and uvPHA-L) were characterized by nuclear magnetic resonance, Fourier transform infrared spectroscopy, gel permeation chromatography, gas chromatography-mass spectrometry and differential scanning calorimetry-thermogravimetric analysis. The structural analysis of the new polymer revealed a dramatic decrease in unsaturated monomer content (8.5%), due to the complete disappearance of the polyunsaturated monomers (C(12:2), C(14:2), and C(14:3)). The cross-linking reaction was also confirmed by atomic force microscopy (AFM) and transmission electron microscopy. AFM showed morphological changes in bacteria cells with and without PHA granules. The microscope techniques provided us with micrographs of the native and cross-linked polymers, showing the formation of a reticular structure as the consequence of the cross-linking reaction.
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Affiliation(s)
- M Bassas
- Laboratori de Microbiologia, Facultat de Farmàcia, Universitat de Barcelona, Joan XXIII s/n, 08028 Barcelona, Spain
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Weir E, Lawlor A, Whelan A, Regan F. The use of nanoparticles in anti-microbial materials and their characterization. Analyst 2008; 133:835-45. [DOI: 10.1039/b715532h] [Citation(s) in RCA: 195] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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50
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Ubbink J, Schär-Zammaretti P. Colloidal properties and specific interactions of bacterial surfaces. Curr Opin Colloid Interface Sci 2007. [DOI: 10.1016/j.cocis.2007.08.004] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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