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Vanzolini T, Di Mambro T, Magnani M, Menotta M. AFM evaluation of a humanized recombinant antibody affecting C. auris cell wall and stability. RSC Adv 2023; 13:6130-6142. [PMID: 36814881 PMCID: PMC9940460 DOI: 10.1039/d2ra07217c] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Accepted: 02/02/2023] [Indexed: 02/22/2023] Open
Abstract
Fungal infections are increasingly impacting on the health of the population and particularly on subjects with a compromised immune system. The resistance phenomenon and the rise of new species carrying sometimes intrinsic and multi-drug resistance to the most commonly used antifungal drugs are greatly concerning healthcare organizations. As a result of this situation, there is growing interest in the development of therapeutic agents against pathogenic fungi. In particular, the Candida genus is responsible for severe life-threatening infections and among its species, C. auris is considered an urgent threat by the Center for Disease Control and Prevention, and is one of the three leading causes of morbidity and mortality worldwide. H5K1 is a humanized monoclonal antibody (hmAb) that selectively binds to β-1,3-glucans, vital components of the fungal cell wall. It has been previously demonstrated that it is active against Candida species, especially against C. auris, reaching its greatest potential when combined with commercially available antifungal drugs. Here we used atomic force microscopy (AFM) to assess the effects of H5K1, alone and in combination with fluconazole, caspofungin and amphotericin B, on C. auris cells. Through an extensive exploration we found that H5K1 has a significant role in the perturbation and remodeling of the fungal cell wall that is reflected in the loss of whole cell integrity. Moreover, it contributes substantially to the alterations in terms of chemical composition, stiffness and roughness induced specifically by caspofungin and amphotericin B. In addition to this, we demonstrated that AFM is a valuable technique to evaluate drug-microorganism interaction.
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Affiliation(s)
- Tania Vanzolini
- Department of Biomolecular Sciences, University of Urbino Carlo Bo Via Saffi 2 61029 Urbino Italy
| | | | - Mauro Magnani
- Department of Biomolecular Sciences, University of Urbino Carlo Bo Via Saffi 2 61029 Urbino Italy
| | - Michele Menotta
- Department of Biomolecular Sciences, University of Urbino Carlo Bo Via Saffi 2 61029 Urbino Italy
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2
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Santos MA, Silva FL, Lira BOV, Cardozo Fh JL, Vasconcelos AG, Araujo AR, Murad AM, Garay AV, Freitas SM, Leite JRSA, Bloch C, Ramada MHS, de Oliveira AL, Brand GD. Probing human proteins for short encrypted antimicrobial peptides reveals Hs10, a peptide with selective activity for gram-negative bacteria. Biochim Biophys Acta Gen Subj 2023; 1867:130265. [PMID: 36280021 DOI: 10.1016/j.bbagen.2022.130265] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Revised: 10/04/2022] [Accepted: 10/17/2022] [Indexed: 11/13/2022]
Abstract
BACKGROUND Some cationic and amphiphilic α-helical segments of proteins adsorb to prokaryotic membranes when synthesized as individual polypeptide sequences, resulting in broad and potent antimicrobial activity. However, amphiphilicity, a determinant physicochemical property for peptide-membrane interactions, can also be observed in some β-sheets. METHODS The software Kamal was used to scan the human reference proteome for short (7-11 amino acid residues) cationic and amphiphilic protein segments with the characteristic periodicity of β-sheets. Some of the uncovered peptides were chemically synthesized, and antimicrobial assays were conducted. Biophysical techniques were used to probe the molecular interaction of one peptide with phospholipid vesicles, lipopolysaccharides (LPS) and the bacterium Escherichia coli. RESULTS Thousands of compatible segments were found in human proteins, five were synthesized, and three presented antimicrobial activity in the micromolar range. Hs10, a nonapeptide fragment of the Complement C3 protein, could inhibit only the growth of tested Gram-negative microorganisms, presenting also little cytotoxicity to human fibroblasts. Hs10 interacted with LPS while transitioning from an unstructured segment to a β-sheet and increased the hydrodynamic radius of LPS particles. This peptide also promoted morphological alterations in E. coli cells. CONCLUSIONS Data presented herein introduce yet another molecular template to probe proteins in search for encrypted membrane-active segments and demonstrates that, using this approach, short peptides with low cytotoxicity and high selectivity to prokaryotic cells might be obtained. GENERAL SIGNIFICANCE This work widens the biotechnological potential of the human proteome as a source of antimicrobial peptides with application in human health.
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Affiliation(s)
- Michele A Santos
- Laboratório de Ressonância Magnética Nuclear, LRMN, Instituto de Química, Universidade de Brasília, Brasília, DF, Brazil; Laboratório de Síntese e Análise de Biomoléculas, LSAB, Instituto de Química, Universidade de Brasília, Brasília, DF, Brazil
| | - Fernanda L Silva
- Laboratório de Síntese e Análise de Biomoléculas, LSAB, Instituto de Química, Universidade de Brasília, Brasília, DF, Brazil
| | - Bianca O V Lira
- Programa de Pós-Graduação em Ciências Genômicas e Biotecnologia, Universidade Católica de Brasília, Brasília, DF, Brazil
| | - José L Cardozo Fh
- Laboratório de Espectrometria de Massa, LEM, Embrapa Recursos Genéticos e Biotecnologia, Brasília, DF, Brazil
| | - Andreanne G Vasconcelos
- Núcleo de Pesquisa em Morfologia e Imunologia Aplicada, NuPMIA, Faculdade de Medicina, Campus Universitário Darcy Ribeiro, Universidade de Brasília, Brasília, DF, Brazil
| | - Alyne R Araujo
- Núcleo de Pesquisa em Biodiversidade e Biotecnologia, Universidade Federal do Piauí, Parnaíba, PI, Brazil
| | - André M Murad
- Laboratório de Espectrometria de Massa, LEM, Embrapa Recursos Genéticos e Biotecnologia, Brasília, DF, Brazil
| | - Aisel V Garay
- Laboratório de Biofísica Molecular, Instituto de Biologia, Universidade de Brasília (IB-CEL/UnB), Campus Darcy Ribeiro, Asa Norte, Brasília, DF, Brazil
| | - Sonia M Freitas
- Laboratório de Biofísica Molecular, Instituto de Biologia, Universidade de Brasília (IB-CEL/UnB), Campus Darcy Ribeiro, Asa Norte, Brasília, DF, Brazil
| | - José Roberto S A Leite
- Núcleo de Pesquisa em Morfologia e Imunologia Aplicada, NuPMIA, Faculdade de Medicina, Campus Universitário Darcy Ribeiro, Universidade de Brasília, Brasília, DF, Brazil
| | - Carlos Bloch
- Laboratório de Espectrometria de Massa, LEM, Embrapa Recursos Genéticos e Biotecnologia, Brasília, DF, Brazil
| | - Marcelo H S Ramada
- Programa de Pós-Graduação em Ciências Genômicas e Biotecnologia, Universidade Católica de Brasília, Brasília, DF, Brazil; Programa de Pós-Graduação em Gerontologia, Universidade Católica de Brasília, Brasília, DF, Brazil
| | - Aline Lima de Oliveira
- Laboratório de Ressonância Magnética Nuclear, LRMN, Instituto de Química, Universidade de Brasília, Brasília, DF, Brazil
| | - Guilherme D Brand
- Laboratório de Síntese e Análise de Biomoléculas, LSAB, Instituto de Química, Universidade de Brasília, Brasília, DF, Brazil.
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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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Zamani E, Johnson TJ, Chatterjee S, Immethun C, Sarella A, Saha R, Dishari SK. Cationic π-Conjugated Polyelectrolyte Shows Antimicrobial Activity by Causing Lipid Loss and Lowering Elastic Modulus of Bacteria. ACS APPLIED MATERIALS & INTERFACES 2020; 12:49346-49361. [PMID: 33089982 PMCID: PMC8926324 DOI: 10.1021/acsami.0c12038] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Cationic, π-conjugated oligo-/polyelectrolytes (CCOEs/CCPEs) have shown great potential as antimicrobial materials to fight against antibiotic resistance. In this work, we treated wild-type and ampicillin-resistant (amp-resistant) Escherichia coli (E. coli) with a promising cationic, π-conjugated polyelectrolyte (P1) with a phenylene-based backbone and investigated the resulting morphological, mechanical, and compositional changes of the outer membrane of bacteria in great detail. The cationic quaternary amine groups of P1 led to electrostatic interactions with negatively charged moieties within the outer membrane of bacteria. Using atomic force microscopy (AFM), high-resolution transmission electron microscopy (TEM), we showed that due to this treatment, the bacterial outer membrane became rougher, decreased in stiffness/elastic modulus (AFM nanoindentation), formed blebs, and released vesicles near the cells. These evidences, in addition to increased staining of the P1-treated cell membrane by lipophilic dye Nile Red (confocal laser scanning microscopy (CLSM)), suggested loosening/disruption of packing of the outer cell envelope and release and exposure of lipid-based components. Lipidomics and fatty acid analysis confirmed a significant loss of phosphate-based outer membrane lipids and fatty acids, some of which are critically needed to maintain cell wall integrity and mechanical strength. Lipidomics and UV-vis analysis also confirmed that the extracellular vesicles released upon treatment (AFM) are composed of lipids and cationic P1. Such surface alterations (vesicle/bleb formation) and release of lipids/fatty acids upon treatment were effective enough to inhibit further growth of E. coli cells without completely disintegrating the cells and have been known as a defense mechanism of the cells against cationic antimicrobial agents.
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Affiliation(s)
- Ehsan Zamani
- Department of Chemical and Biomolecular Engineering, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, United States
| | - Tyler J. Johnson
- Department of Chemical and Biomolecular Engineering, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, United States
| | - Shyambo Chatterjee
- Department of Chemical and Biomolecular Engineering, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, United States
| | - Cheryl Immethun
- Department of Chemical and Biomolecular Engineering, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, United States
| | - Anandakumar Sarella
- Nebraska Center for Materials and Nanoscience, Voelte-Keegan Nanoscience Research Center, University of Nebraska-Lincoln, Lincoln, NE 68588-0298, United States
| | - Rajib Saha
- Department of Chemical and Biomolecular Engineering, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, United States
| | - Shudipto Konika Dishari
- Department of Chemical and Biomolecular Engineering, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, United States
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Mathelié-Guinlet M, Grauby-Heywang C, Martin A, Février H, Moroté F, Vilquin A, Béven L, Delville MH, Cohen-Bouhacina T. Detrimental impact of silica nanoparticles on the nanomechanical properties of Escherichia coli, studied by AFM. J Colloid Interface Sci 2018; 529:53-64. [PMID: 29883930 DOI: 10.1016/j.jcis.2018.05.098] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2018] [Revised: 05/24/2018] [Accepted: 05/27/2018] [Indexed: 12/17/2022]
Abstract
Despite great innovative and technological promises, nanoparticles (NPs) can ultimately exert an antibacterial activity by affecting the cell envelope integrity. This envelope, by conferring the cell its rigidity and protection, is intimately related to the mechanical behavior of the bacterial surface. Depending on their size, surface chemistry, shape, NPs can induce damages to the cell morphology and structure among others, and are therefore expected to alter the overall mechanical properties of bacteria. Although Atomic Force Microscopy (AFM) stands as a powerful tool to study biological systems, with high resolution and in near physiological environment, it has rarely been applied to investigate at the same time both morphological and mechanical degradations of bacteria upon NPs treatment. Consequently, this study aims at quantifying the impact of the silica NPs (SiO2-NPs) on the mechanical properties of E. coli cells after their exposure, and relating it to their toxic activity under a critical diameter. Cell elasticity was calculated by fitting the force curves with the Hertz model, and was correlated with the morphological study. SiO2-NPs of 100 nm diameter did not trigger any significant change in the Young modulus of E. coli, in agreement with the bacterial intact morphology and membrane structure. On the opposite, the 4 nm diameter SiO2-NPs did induce a significant decrease in E. coli Young modulus, mainly associated with the disorganization of lipopolysaccharides in the outer membrane and the permeation of the underlying peptidoglycan layer. The subsequent toxic behavior of these NPs is finally confirmed by the presence of membrane residues, due to cell lysis, exhibiting typical adhesion features.
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Affiliation(s)
- Marion Mathelié-Guinlet
- Univ. Bordeaux, CNRS, LOMA, UMR5798, 351 cours de la Libération, 33400 Talence, France; Univ. Bordeaux, CNRS, ICMCB, UMR5026, 87 avenue du Dr Albert Schweitzer, 33608 Pessac, France
| | | | - Axel Martin
- Univ. Bordeaux, CNRS, LOMA, UMR5798, 351 cours de la Libération, 33400 Talence, France
| | - Hugo Février
- Univ. Bordeaux, CNRS, LOMA, UMR5798, 351 cours de la Libération, 33400 Talence, France
| | - Fabien Moroté
- Univ. Bordeaux, CNRS, LOMA, UMR5798, 351 cours de la Libération, 33400 Talence, France
| | - Alexandre Vilquin
- Univ. Bordeaux, CNRS, LOMA, UMR5798, 351 cours de la Libération, 33400 Talence, France
| | - Laure Béven
- Univ. Bordeaux, INRA, UMR 1332 Biologie du Fruit et Pathologie, 33882 Villenave-d'Ornon, France
| | - Marie-Hélène Delville
- Univ. Bordeaux, CNRS, ICMCB, UMR5026, 87 avenue du Dr Albert Schweitzer, 33608 Pessac, France.
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Mathew RT, Cooney RP, Malmstrom J, Doyle CS. Atomic Force Microscopy and Angular-Dependent X-ray Photoelectron Spectroscopy Studies of Anchored Quaternary Ammonium Salt Biocides on Quartz Surfaces. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:4750-4761. [PMID: 29597350 DOI: 10.1021/acs.langmuir.8b00535] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
A siloxane surface-anchored quaternary ammonium salt (AQAS: BIOSAFE HM4100 in this study) has been chemisorbed onto a quartz substrate. The aim of this study is to elucidate, using atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS), the structure of the chemisorbed AQAS layers. The AQAS biocide includes a C18 alkyl chain previously invoked in lysis potency. The AQAS coverage appears in zones on the surface, which include a first layer (2.6 ± 0.1 nm) and multilayering that were explored using AFM. The XPS data exhibited two N 1s signals at about 402 and 399 eV, with only the former exhibiting angular dependence. This signal at 402 eV was assigned to the first anchored layer with perpendicular orientation determined by the AQAS anchoring to the surface. In preliminary AFM studies of bacteria on these AQAS surfaces, perturbations on the Staphylococcus aureus cells and the degradation of Escherichia coli cells suggest lysis potency.
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7
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Atomic force microscopy for the investigation of molecular and cellular behavior. Micron 2016; 89:60-76. [DOI: 10.1016/j.micron.2016.07.011] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Accepted: 07/27/2016] [Indexed: 12/19/2022]
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López-Jiménez L, Fusté E, Martínez-Garriga B, Arnabat-Domínguez J, Vinuesa T, Viñas M. Effects of photodynamic therapy on Enterococcus faecalis biofilms. Lasers Med Sci 2015; 30:1519-26. [PMID: 25917515 PMCID: PMC4475243 DOI: 10.1007/s10103-015-1749-y] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Accepted: 03/20/2015] [Indexed: 11/30/2022]
Abstract
Microbial biofilms are involved in almost all infectious pathologies of the oral cavity. This has led to the search for novel therapies specifically aimed at biofilm elimination. In this study, we used atomic force microscopy (AFM) to visualize injuries and to determine surface roughness, as well as confocal laser scanning microscopy (CLSM) to enumerate live and dead bacterial cells, to determine the effects of photodynamic therapy (PDT) on Enterococcus faecalis biofilms. The AFM images showed that PDT consisting of methylene blue and a 670-nm diode laser (output power 280 mW during 30 s) or toluidine blue and a 628-nm LED light (output power 1000 mW during 30 s) induced severe damage, including cell lysis, to E. faecalis biofilms, with the former also causing an important increase in surface roughness. These observations were confirmed by the increase in dead cells determined using CLSM. Our results highlight the potential of PDT as a promising method to achieve successful oral disinfection.
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Affiliation(s)
- L López-Jiménez
- Laboratory of Molecular Microbiology and Antimicrobials, Department of Pathology and Experimental Therapeutics, Medical School, IDIBELL-University of Barcelona, Barcelona, Spain
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Longo G, Kasas S. Effects of antibacterial agents and drugs monitored by atomic force microscopy. WILEY INTERDISCIPLINARY REVIEWS-NANOMEDICINE AND NANOBIOTECHNOLOGY 2014; 6:230-44. [PMID: 24616433 DOI: 10.1002/wnan.1258] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2013] [Revised: 01/06/2014] [Accepted: 01/13/2014] [Indexed: 11/07/2022]
Abstract
Originally invented for topographic imaging, atomic force microscopy (AFM) has evolved into a multifunctional biological toolkit, enabling to measure structural and functional details of cells and molecules. Its versatility and the large scope of information it can yield make it an invaluable tool in any biologically oriented laboratory, where researchers need to perform characterizations of living samples as well as single molecules in quasi-physiological conditions and with nanoscale resolution. In the last 20 years, AFM has revolutionized the characterization of microbial cells by allowing a better understanding of their cell wall and of the mechanism of action of drugs and by becoming itself a powerful diagnostic tool to study bacteria. Indeed, AFM is much more than a high-resolution microscopy technique. It can reconstruct force maps that can be used to explore the nanomechanical properties of microorganisms and probe at the same time the morphological and mechanical modifications induced by external stimuli. Furthermore it can be used to map chemical species or specific receptors with nanometric resolution directly on the membranes of living organisms. In summary, AFM offers new capabilities and a more in-depth insight in the structure and mechanics of biological specimens with an unrivaled spatial and force resolution. Its application to the study of bacteria is extremely significant since it has already delivered important information on the metabolism of these small microorganisms and, through new and exciting technical developments, will shed more light on the real-time interaction of antimicrobial agents and bacteria.
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Affiliation(s)
- Giovanni Longo
- Ecole Polytechnique Fédérale de Lausanne, LPMV, Lausanne, Switzerland; Istituto Superiore di Sanità, Rome, Italy
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Pillet F, Chopinet L, Formosa C, Dague E. Atomic Force Microscopy and pharmacology: from microbiology to cancerology. Biochim Biophys Acta Gen Subj 2013; 1840:1028-50. [PMID: 24291690 DOI: 10.1016/j.bbagen.2013.11.019] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2013] [Revised: 11/18/2013] [Accepted: 11/20/2013] [Indexed: 02/06/2023]
Abstract
BACKGROUND Atomic Force Microscopy (AFM) has been extensively used to study biological samples. Researchers take advantage of its ability to image living samples to increase our fundamental knowledge (biophysical properties/biochemical behavior) on living cell surface properties, at the nano-scale. SCOPE OF REVIEW AFM, in the imaging modes, can probe cells morphological modifications induced by drugs. In the force spectroscopy mode, it is possible to follow the nanomechanical properties of a cell and to probe the mechanical modifications induced by drugs. AFM can be used to map single molecule distribution at the cell surface. We will focus on a collection of results aiming at evaluating the nano-scale effects of drugs, by AFM. Studies on yeast, bacteria and mammal cells will illustrate our discussion. Especially, we will show how AFM can help in getting a better understanding of drug mechanism of action. MAJOR CONCLUSIONS This review demonstrates that AFM is a versatile tool, useful in pharmacology. In microbiology, it has been used to study the drugs fighting Candida albicans or Pseudomonas aeruginosa. The major conclusions are a better understanding of the microbes' cell wall and of the drugs mechanism of action. In cancerology, AFM has been used to explore the effects of cytotoxic drugs or as an innovative diagnostic technology. AFM has provided original results on cultured cells, cells extracted from patient and directly on patient biopsies. GENERAL SIGNIFICANCE This review enhances the interest of AFM technologies for pharmacology. The applications reviewed range from microbiology to cancerology.
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Affiliation(s)
- Flavien Pillet
- CNRS, LAAS, 7 avenue du colonel Roche, F-31077 Toulouse Cedex 4, France; Université de Toulouse, UPS, INSA, INP, ISAE, UT1, UTM, LAAS, ITAV, F-31077 Toulouse Cedex 4, France
| | - Louise Chopinet
- CNRS, IPBS-UMR 5089, BP64182, 205 route de Narbonne, F-31077 Toulouse Cedex 4, France; Université de Toulouse, UPS, INSA, INP, ISAE, UT1, UTM, LAAS, ITAV, F-31077 Toulouse Cedex 4, France
| | - Cécile Formosa
- CNRS, LAAS, 7 avenue du colonel Roche, F-31077 Toulouse Cedex 4, France; Université de Toulouse, UPS, INSA, INP, ISAE, UT1, UTM, LAAS, ITAV, F-31077 Toulouse Cedex 4, France; CNRS, UMR 7565, SRSMC, Vandoeuvre-lès-Nancy, France; Université de Lorraine, UMR 7565, Faculté de Pharmacie, Nancy, France
| | - Etienne Dague
- CNRS, LAAS, 7 avenue du colonel Roche, F-31077 Toulouse Cedex 4, France; Université de Toulouse, UPS, INSA, INP, ISAE, UT1, UTM, LAAS, ITAV, F-31077 Toulouse Cedex 4, France; CNRS; ITAV-USR 3505; F31106 Toulouse, France.
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Consuegra J, de Lima ME, Santos D, Sinisterra RD, Cortés ME. Peptides: β-cyclodextrin inclusion compounds as highly effective antimicrobial and anti-epithelial proliferation agents. J Periodontol 2013; 84:1858-68. [PMID: 23510146 DOI: 10.1902/jop.2013.120679] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
BACKGROUND The use of antimicrobial peptides (AMPs) as therapeutic agents for periodontal infections has great advantages, such as broad spectrum of action, low toxicity, and limited bacterial resistance. However, their practical use is limited because of the large amount of peptide required to exercise the microbicidal function. METHODS LyeTxI, LL37f, and KR12 cationic peptides were prepared with β-cyclodextrin (βCD) at 1:1 molar ratios. The susceptibility of Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans, and Fusobacterium nucleatum were assessed in anaerobic conditions. Cytotoxicity assays were performed using osteoblast and Caco-2 epithelial cells, and hemolytic activity was assessed on rabbit erythrocytes at an absorbance of 414 nm. Parameters of surface roughness and electrical charge were established by atomic force microscopy and zeta (ζ) potential, respectively. RESULTS AMP/βCDs drastically decreased the peptide concentration required for activity against the bacteria tested. Moreover, AMPs associated with βCD were able to modify cell-surface parameters, such as roughness and ζ potential. On the other hand, AMP/βCD did not alter the degree of hemolysis induced by the pure AMPs. The effective concentration at half-maximum values of the peptides and compounds on osteoblasts were greater than the concentrations required to achieve inhibition of bacterial growth in all the species tested. AMP/βCDs inhibited the proliferation of Caco-2 epithelial cells in a more efficient manner than AMPs alone. CONCLUSION AMP/βCD compounds more effectively inhibit periodontopathogenic bacteria than AMPs alone, with the additional ability of inhibiting the proliferation of epithelial cells at concentrations that are non-cytotoxic for osteoblasts and erythrocytes.
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Affiliation(s)
- Jessika Consuegra
- Department of Physiology and Biophysics, Biologic Science Institute (ICB), Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
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Morphostructural Damage in Food-Spoiling Bacteria due to the Lemon Grass Oil and Its Vapour: SEM, TEM, and AFM Investigations. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2012; 2012:692625. [PMID: 23082083 PMCID: PMC3469203 DOI: 10.1155/2012/692625] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/24/2012] [Accepted: 08/26/2012] [Indexed: 12/01/2022]
Abstract
In this study, antimicrobial activity and morphostructural damages due to lemon grass oil (LGO) and its vapour (LGOV) against Escherichia coli strains were investigated. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of LGO were determined by broth-dilution method to be 0.288 mg/mL and 0.567 mg/mL, respectively. Furthermore, the zone of inhibition (45 mm) due to the vapour phase antimicrobial efficacy evaluated using disc volatilization assay was compared with that using disc diffusion assay (i.e., 13.5 mm for the same dose of oil). The morphological and ultrastructural alterations in LGO- and LGOV-treated E. coli cells were studied using scanning electron microscopy (SEM), transmission electron microscopy (TEM), and atomic-force microscopy (AFM). In SEM observation, LGO-treated cells appeared to be aggregated and partially deformed, while LGOV-treated cells lost their turgidity, and the cytoplasmic material completely leaked from the cells. In TEM observation, extensive intracytoplasmic changes and various abnormalities were observed in LGOV-treated cells more than LGO-treated cells. Significant variations in the height and root mean square values of untreated, LGO-, and LGOV-treated E. coli cells were noticed by AFM. Present results indicate that LGO is highly effective against E. coli in vapour phase.
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Antonio PD, Lasalvia M, Perna G, Capozzi V. Scale-independent roughness value of cell membranes studied by means of AFM technique. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2012; 1818:3141-8. [PMID: 22897980 DOI: 10.1016/j.bbamem.2012.08.001] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2012] [Revised: 07/31/2012] [Accepted: 08/02/2012] [Indexed: 12/25/2022]
Abstract
The roughness of cell membrane is a very interesting indicator of cell's health state. Atomic Force Microscopy allows us to investigate the roughness of cell membrane in great detail, but the obtained roughness value is scale-dependent, i.e. it strongly depends on measurement parameters, as scanning area and step size. The scale-dependence of the roughness value can be reduced by means of data filtration techniques, that are not standardized at nanometric scale, especially as far as biological data are concerned. In this work, a new method, based on the changes of values of some roughness parameter (root mean square roughness and skewness) as a function of filtration frequencies, has been implemented to optimize data filtering procedure in the calculation of cell membrane roughness. In this way, a root mean square roughness value independent of cell shape, membrane micro-irregularities and measurement parameters can be obtained. Moreover, different filtration frequencies selected with this method allow us to discriminate different surface regimes (nominal form, waviness and roughness) belonging to the raw cell profile, each one related to different features of the cell surface.
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Affiliation(s)
- Palma D Antonio
- Dipartimento di Medicina Clinica e Sperimentale, Università di Foggia, Viale Pinto, Italy
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14
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Liu S, Ng AK, Xu R, Wei J, Tan CM, Yang Y, Chen Y. Antibacterial action of dispersed single-walled carbon nanotubes on Escherichia coli and Bacillus subtilis investigated by atomic force microscopy. NANOSCALE 2010; 2:2744-2750. [PMID: 20877897 DOI: 10.1039/c0nr00441c] [Citation(s) in RCA: 92] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Single-walled carbon nanotubes (SWCNTs) exhibit strong antibacterial activities. Direct contact between bacterial cells and SWCNTs may likely induce cell damages. Therefore, the understanding of SWCNT-bacteria interactions is essential in order to develop novel SWCNT-based materials for their potential environmental, imaging, therapeutic, and military applications. In this preliminary study, we utilized atomic force microscopy (AFM) to monitor dynamic changes in cell morphology and mechanical properties of two typical bacterial models (gram-negative Escherichia coli and gram-positive Bacillus subtilis) upon incubation with SWCNTs. The results demonstrated that individually dispersed SWCNTs in solution develop nanotube networks on the cell surface, and then destroy the bacterial envelopes with leakage of the intracellular contents. The cell morphology changes observed on air dried samples are accompanied by an increase in cell surface roughness and a decrease in surface spring constant. To mimic the collision between SWCNTs and cells, a sharp AFM tip of 2 nm was chosen to introduce piercings on the cell surface. No clear physical damages were observed if the applied force was below 10 nN. Further analysis also indicates that a single collision between one nanotube and a bacterial cell is unlikely to introduce direct physical damage. Hence, the antibacterial activity of SWCNTs is the accumulation effect of large amount of nanotubes through interactions between SWCNT networks and bacterial cells.
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Affiliation(s)
- Shaobin Liu
- School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore 637459
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15
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Tyagi AK, Malik A. Liquid and vapour-phase antifungal activities of selected essential oils against Candida albicans: microscopic observations and chemical characterization of Cymbopogon citratus. BMC COMPLEMENTARY AND ALTERNATIVE MEDICINE 2010; 10:65. [PMID: 21067604 PMCID: PMC2994787 DOI: 10.1186/1472-6882-10-65] [Citation(s) in RCA: 117] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/13/2010] [Accepted: 11/10/2010] [Indexed: 12/16/2022]
Abstract
BACKGROUND Use of essential oils for controlling Candida albicans growth has gained significance due to the resistance acquired by pathogens towards a number of widely-used drugs. The aim of this study was to test the antifungal activity of selected essential oils against Candida albicans in liquid and vapour phase and to determine the chemical composition and mechanism of action of most potent essential oil. METHODS Minimum Inhibitory concentration (MIC) of different essential oils in liquid phase, assayed through agar plate dilution, broth dilution & 96-well micro plate dilution method and vapour phase activity evaluated through disc volatilization method. Reduction of C. albicans cells with vapour exposure was estimated by kill time assay. Morphological alteration in treated/untreated C. albicans cells was observed by the Scanning electron microscopy (SEM)/Atomic force microscopy (AFM) and chemical analysis of the strongest antifungal agent/essential oil has been done by GC, GC-MS. RESULTS Lemon grass (Cymbopogon citratus) essential oil exhibited the strongest antifungal effect followed by mentha (Mentha piperita) and eucalyptus (Eucalyptus globulus) essential oil. The MIC of lemon grass essential oil in liquid phase (288 mg/l) was significantly higher than that in the vapour phase (32.7 mg/l) and a 4 h exposure was sufficient to cause 100% loss in viability of C. albicans cells. SEM/AFM of C. albicans cells treated with lemon grass essential oil at MIC level in liquid and vapour phase showed prominent shrinkage and partial degradation, respectively, confirming higher efficacy of vapour phase. GC-MS analysis revealed that lemon grass essential oil was dominated by oxygenated monoterpenes (78.2%); α-citral or geranial (36.2%) and β-citral or neral (26.5%), monoterpene hydrocarbons (7.9%) and sesquiterpene hydrocarbons (3.8%). CONCLUSION Lemon grass essential oil is highly effective in vapour phase against C. albicans, leading to deleterious morphological changes in cellular structures and cell surface alterations.
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Affiliation(s)
- Amit K Tyagi
- Applied Microbiology Laboratory, Centre for Rural Development & Technology, Indian Institute of Technology Delhi, New Delhi- 110 016, India
| | - Anushree Malik
- Applied Microbiology Laboratory, Centre for Rural Development & Technology, Indian Institute of Technology Delhi, New Delhi- 110 016, India
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16
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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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17
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Li A, Ho B, Ding JL, Lim CT. Use of atomic force microscopy as a tool to understand the action of antimicrobial peptides on bacteria. Methods Mol Biol 2010; 618:235-247. [PMID: 20094868 DOI: 10.1007/978-1-60761-594-1_15] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Atomic force microscopy (AFM) has been extensively used to image the three-dimensional surface morphology of a broad range of biological samples, including Gram-negative bacteria, imaged in the presence of antimicrobial peptides (AMPs). Although this technique provides high molecular resolution, it only requires minimum sample treatment and can even be performed in liquid and at varying temperatures while keeping the bacterial cells viable. In this chapter, we describe an easy, fast, and yet effective method for preparing AMP-treated Gram-negative bacteria samples for AFM imaging. The results obtained using this method show a series of morphological changes of Gram-negative bacteria upon treatment with selected AMPs, thus providing vivid insights into the mechanisms of how AMPs perturb and destroy Gram-negative bacteria in a stepwise manner. Technical details for performing AFM so as to obtain reliable and high-resolution images will also be discussed, together with some possible artifacts and troubleshooting.
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Affiliation(s)
- Ang Li
- Singapore-MIT Alliance (SMA), National University of Singapore, Kent Ridge, Singapore
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18
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Strandberg E, Tremouilhac P, Wadhwani P, Ulrich AS. Synergistic transmembrane insertion of the heterodimeric PGLa/magainin 2 complex studied by solid-state NMR. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2009; 1788:1667-79. [DOI: 10.1016/j.bbamem.2008.12.018] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2008] [Revised: 11/21/2008] [Accepted: 12/11/2008] [Indexed: 11/16/2022]
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19
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Fernandes JC, Eaton P, Gomes AM, Pintado ME, Xavier Malcata F. Study of the antibacterial effects of chitosans on Bacillus cereus (and its spores) by atomic force microscopy imaging and nanoindentation. Ultramicroscopy 2009; 109:854-60. [DOI: 10.1016/j.ultramic.2009.03.015] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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20
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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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21
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Nanomechanical Characterization of the Triple β-Helix Domain in the Cell Puncture Needle of Bacteriophage T4 Virus. Cell Mol Bioeng 2009. [DOI: 10.1007/s12195-009-0047-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
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22
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de Morais LC, Bernardes-Filho R, Assis OBG. Wettability and bacteria attachment evaluation of multilayer proteases films for biosensor application. World J Microbiol Biotechnol 2008. [DOI: 10.1007/s11274-008-9873-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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23
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Eaton P, Fernandes JC, Pereira E, Pintado ME, Xavier Malcata F. Atomic force microscopy study of the antibacterial effects of chitosans on Escherichia coli and Staphylococcus aureus. Ultramicroscopy 2008; 108:1128-34. [PMID: 18556125 DOI: 10.1016/j.ultramic.2008.04.015] [Citation(s) in RCA: 220] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Chitosan has been reported to be a non-toxic, biodegradable antibacterial agent. The aim of this work was to elucidate the relationship between the molecular weight of chitosan and its antimicrobial activity upon two model microorganisms, one Gram-positive (Staphylococcus aureus) and one Gram-negative (Escherichia coli). Atomic force microscopy (AFM) imaging was used to obtain high-resolution images of the effect of chitosans on the bacterial morphology. The AFM measurements were correlated with viable cell numbers, which show that the two species reacted differently to the high- and low-molecular-weight chitosan derivatives. The images obtained revealed not only the antibacterial effects, but also the response strategies used by the bacteria; cell wall collapse and morphological changes reflected cell death, whereas clustering of bacteria appeared to be associated with cell survival. In addition, nanoindentation experiments with the AFM revealed mechanical changes in the bacterial cell wall induced by the treatment. The nanoindentation results suggested that despite little modification observed in the Gram-positive bacteria in morphological studies, cell wall damage had indeed occurred, since cell wall stiffness was reduced after chitooligosaccharide treatment.
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Affiliation(s)
- Peter Eaton
- REQUIMTE, Departamento de Química, Faculdade de Ciências da Universidade do Porto, Rua do Campo Alegre, 4169-007 Porto, Portugal.
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24
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Santos RP, Arruda TTP, Carvalho CBM, Carneiro VA, Braga LQV, Teixeira EH, Arruda FVS, Cavada BS, Havt A, de Oliveira TM, Bezerra GA, Freire VN. Correlation between Enterococcus faecalis biofilms development stage and quantitative surface roughness using atomic force microscopy. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2008; 14:150-158. [PMID: 18312720 DOI: 10.1017/s1431927608080227] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2007] [Accepted: 09/11/2007] [Indexed: 05/26/2023]
Abstract
Biofilms are assemblages of microorganisms and their associated extracellular products at an interface and typically with an abiotic or biotic surface. The study of the morphology of biofilms is important because they are associated with processes of biofouling, corrosion, catalysis, pollutant transformation, dental caries, drug resistance, and so forth. In the literature, biofilms have been examined by atomic force microscopy (AFM), which has proven to be a potent tool to study different aspects of the biofilm development on solid surfaces. In this work, we used AFM to investigate topographical changes during the development process of Enterococcus faecalis biofilms, which were generated on sterile cellulose nitrate membrane (CNM) filters in brain heart infusion (BHI) broth agar blood plates after 24, 36, 72, 192, and 360 h. AFM height images showed topographical changes due to biofilm development, which were used to characterize several aspects of the bacterial surface, such as the presence of extracellular polymeric substance, and the biofilm development stage. Changes in the development stage of the biofilm were shown to correlate with changes in the surface roughness as quantified through the mean roughness.
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Affiliation(s)
- Ricardo P Santos
- Laboratório de Ciência e Tecnologia de Materiais, Departamento de Física, Universidade Federal do Ceará, Caixa Postal 6030, Campus do Pici, 60455-900 Fortaleza, Ceará, Brazil.
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25
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Kasas S, Dietler G. Probing nanomechanical properties from biomolecules to living cells. Pflugers Arch 2008; 456:13-27. [DOI: 10.1007/s00424-008-0448-y] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2008] [Accepted: 01/09/2008] [Indexed: 12/27/2022]
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26
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Rossetto G, Bergese P, Colombi P, Depero LE, Giuliani A, Nicoletto SF, Pirri G. Atomic force microscopy evaluation of the effects of a novel antimicrobial multimeric peptide on Pseudomonas aeruginosa. NANOMEDICINE-NANOTECHNOLOGY BIOLOGY AND MEDICINE 2007; 3:198-207. [PMID: 17702663 DOI: 10.1016/j.nano.2007.06.002] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2007] [Revised: 05/23/2007] [Accepted: 06/22/2007] [Indexed: 01/01/2023]
Abstract
In this article we evaluated by atomic force microscopy (AFM) the effects of the (novel) tetrabranched antimicrobial peptide SB006 on morphology and mechanical properties of the gram-negative bacterium Pseudomonas aeruginosa. AFM imaging showed that SB006 causes the appearance of significant fragmentariness in the bacterial membrane and a severe volume decrease. Quantitative evaluation of the degree of fragmentariness was allowed by a new ad hoc image analysis procedure. The rigidity of the treated and untreated bacteria was measured through AFM tip nanoindentation measurements, and no differences registered. These results support the membrane interaction hypothesis, according to which SB006 targets the bacterial membranes and disrupts their permeability (allowing the leakage of cytoplasmic material and the subsequent shrinkage), but it does not affect the bacterium wall, which determines its rigidity.
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Affiliation(s)
- Greta Rossetto
- INSTM and Laboratorio di Chimica per le Tecnologie, Università di Brescia, Brescia, Italy
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