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Hossain MF, Akter MA, Sohan MSR, Sultana DN, Reza MA, Hoque KMF. Bioremediation potential of hydrocarbon degrading bacteria: isolation, characterization, and assessment. Saudi J Biol Sci 2022; 29:211-216. [PMID: 35002411 PMCID: PMC8717088 DOI: 10.1016/j.sjbs.2021.08.069] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Revised: 08/20/2021] [Accepted: 08/22/2021] [Indexed: 10/30/2022] Open
Abstract
Oil contamination is a worldwide concern now. However, oil contaminated environment is enriched with microorganisms that can utilize petroleum oil and use hydrocarbon for their growth, nutrition and metabolic activities. In the present study, bacteria present in the oil contaminated soil were isolated by enrichment culture technique using Minimal Salt (MS) media supplemented with diesel oil and burned engine oil as a sole carbon source. The isolated bacteria were characterized by morphological and biochemical tests and identified by molecular tool through cycle sequencing method. Three isolates were morphologically characterized as gram-negative, cocci shaped and 16S rRNA sequence analysis revealed that the isolates are closely related to Pseudomonas sp., Acinetobacter sp., and Enterobacter sp. respectively. Growth condition was optimized at pH 7.0 and temperature 37 °C. All the isolates were susceptible to several antibiotics and they have no antagonistic effect with soil beneficial bacteria. Three isolates were grown in two different concentrations of diesel oil and burned engine oil (4% v/v and 8%, v/v) respectively. Study revealed that with increasing the concentration of diesel oil in the media the growth rate of all the isolates were decreased. In contrast, the growth rates of all the three isolates were increased, with increasing concentration of burned engine oil. In our study, all the isolates showed their degradation efficacy in 4% v/v diesel oil and in 8% v/v burned engine oil. So, our research clearly shows that the isolates could be potentially used for bioremediation purposes for cleaning up petroleum polluted area.
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Affiliation(s)
- Md Forhad Hossain
- Molecular Biology and Protein Science Laboratory, Department of Genetic Engineering and Biotechnology, University of Rajshahi, Rajshahi 6205, Bangladesh
| | - Mst Ambia Akter
- Molecular Biology and Protein Science Laboratory, Department of Genetic Engineering and Biotechnology, University of Rajshahi, Rajshahi 6205, Bangladesh
| | - Md Sohanur Rahman Sohan
- Molecular Biology and Protein Science Laboratory, Department of Genetic Engineering and Biotechnology, University of Rajshahi, Rajshahi 6205, Bangladesh
| | - Dr Nigar Sultana
- Deparment of Pediatric, Rajshahi Medical College & Hospital, Rajshahi, Bangladesh
| | - Md Abu Reza
- Molecular Biology and Protein Science Laboratory, Department of Genetic Engineering and Biotechnology, University of Rajshahi, Rajshahi 6205, Bangladesh
| | - Kazi Md Faisal Hoque
- Molecular Biology and Protein Science Laboratory, Department of Genetic Engineering and Biotechnology, University of Rajshahi, Rajshahi 6205, Bangladesh
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Gang H, Bian P, He X, He X, Bao X, Mu B, Li Y, Yang S. Mixing of Surfactin, an Anionic Biosurfactant, with Alkylbenzene Sulfonate, a Chemically Synthesized Anionic Surfactant, at the
n
‐Decane
/Water Interface. J SURFACTANTS DETERG 2021. [DOI: 10.1002/jsde.12495] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Affiliation(s)
- Hong‐Ze Gang
- State Key Laboratory of Bioreactor Engineering and School of Chemistry and Molecular Engineering and Engineering Research Center of Microbial Enhanced Oil Recovery, MOE East China University of Science and Technology Shanghai 200237 China
- Shanghai Collaborative Innovation Center for Biomanufacturing Technology Shanghai 200237 China
| | - Peng‐Cheng Bian
- State Key Laboratory of Bioreactor Engineering and School of Chemistry and Molecular Engineering and Engineering Research Center of Microbial Enhanced Oil Recovery, MOE East China University of Science and Technology Shanghai 200237 China
| | - Xiuli He
- State Key Laboratory of Bioreactor Engineering and School of Chemistry and Molecular Engineering and Engineering Research Center of Microbial Enhanced Oil Recovery, MOE East China University of Science and Technology Shanghai 200237 China
| | - Xiujuan He
- Sinopec Key Lab of Surfactants for EOR Sinopec Shanghai Research Institute of Petrochemical Technology North Pudong 1658 Shanghai 201208 China
| | - Xinning Bao
- State Key Laboratory of Bioreactor Engineering and School of Chemistry and Molecular Engineering and Engineering Research Center of Microbial Enhanced Oil Recovery, MOE East China University of Science and Technology Shanghai 200237 China
- Sinopec Key Lab of Surfactants for EOR Sinopec Shanghai Research Institute of Petrochemical Technology North Pudong 1658 Shanghai 201208 China
| | - Bo‐Zhong Mu
- State Key Laboratory of Bioreactor Engineering and School of Chemistry and Molecular Engineering and Engineering Research Center of Microbial Enhanced Oil Recovery, MOE East China University of Science and Technology Shanghai 200237 China
- Shanghai Collaborative Innovation Center for Biomanufacturing Technology Shanghai 200237 China
| | - Yingcheng Li
- Sinopec Key Lab of Surfactants for EOR Sinopec Shanghai Research Institute of Petrochemical Technology North Pudong 1658 Shanghai 201208 China
| | - Shi‐Zhong Yang
- State Key Laboratory of Bioreactor Engineering and School of Chemistry and Molecular Engineering and Engineering Research Center of Microbial Enhanced Oil Recovery, MOE East China University of Science and Technology Shanghai 200237 China
- Shanghai Collaborative Innovation Center for Biomanufacturing Technology Shanghai 200237 China
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3
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Materon EM, Nascimento GF, Shimizu FM, Câmara AS, Sandrino B, Faria RC, Oliveira ON. Role of sphingomyelin on the interaction of the anticancer drug gemcitabine hydrochloride with cell membrane models. Colloids Surf B Biointerfaces 2020; 196:111357. [DOI: 10.1016/j.colsurfb.2020.111357] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 09/10/2020] [Accepted: 09/11/2020] [Indexed: 12/17/2022]
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4
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Goussous S, Fellows A, Casford M, Davies P. A time domain study of surfactin penetrating a phospholipid monolayer at the air-water interface investigated using sum frequency generation spectroscopy, infrared reflection absorption spectroscopy, and AFM-nano infrared microscopy. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2019; 1861:1568-1578. [DOI: 10.1016/j.bbamem.2019.06.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Revised: 05/13/2019] [Accepted: 06/07/2019] [Indexed: 01/06/2023]
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5
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Role of Lipid Composition, Physicochemical Interactions, and Membrane Mechanics in the Molecular Actions of Microbial Cyclic Lipopeptides. J Membr Biol 2019; 252:131-157. [PMID: 31098678 DOI: 10.1007/s00232-019-00067-4] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Accepted: 05/02/2019] [Indexed: 10/26/2022]
Abstract
Several experimental and theoretical studies have extensively investigated the effects of a large diversity of antimicrobial peptides (AMPs) on model lipid bilayers and living cells. Many of these peptides disturb cells by forming pores in the plasma membrane that eventually lead to the cell death. The complexity of these peptide-lipid interactions is mainly related to electrostatic, hydrophobic and topological issues of these counterparts. Diverse studies have shed some light on how AMPs act on lipid bilayers composed by different phospholipids, and how mechanical properties of membranes could affect the antimicrobial effects of such compounds. On the other hand, cyclic lipopeptides (cLPs), an important class of microbial secondary metabolites, have received comparatively less attention. Due to their amphipathic structures, cLPs exhibit interesting biological activities including interactions with biofilms, anti-bacterial, anti-fungal, antiviral, and anti-tumoral properties, which deserve more investigation. Understanding how physicochemical properties of lipid bilayers contribute and determining the antagonistic activity of these secondary metabolites over a broad spectrum of microbial pathogens could establish a framework to design and select effective strategies of biological control. This implies unravelling-at the biophysical level-the complex interactions established between cLPs and lipid bilayers. This review presents, in a systematic manner, the diversity of lipidated antibiotics produced by different microorganisms, with a critical analysis of the perturbing actions that have been reported in the literature for this specific set of membrane-active lipopeptides during their interactions with model membranes and in vivo. With an overview on the mechanical properties of lipid bilayers that can be experimentally determined, we also discuss which parameters are relevant in the understanding of those perturbation effects. Finally, we expose in brief, how this knowledge can help to design novel strategies to use these biosurfactants in the agronomic and pharmaceutical industries.
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Wang D, de Jong DH, Rühling A, Lesch V, Shimizu K, Wulff S, Heuer A, Glorius F, Galla HJ. Imidazolium-Based Lipid Analogues and Their Interaction with Phosphatidylcholine Membranes. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:12579-12592. [PMID: 27934518 DOI: 10.1021/acs.langmuir.6b02496] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
4,5-Dialkylated imidazolium lipid salts are a new class of lipid analogues showing distinct biological activities. The potential effects of the imidazolium lipids on artificial lipid membranes and the corresponding membrane interactions was analyzed. Therefore, 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) was employed to create an established lipid monolayer model and a bilayer membrane. Mixed monolayers of DPPC and 4,5-dialkylimidazolium lipids differing by their alkyl chain length (C7, C11, and C15) were characterized by surface pressure-area (π-A) isotherms using a Wilhelmy film balance in combination with epifluorescence microscopy. Monolayer hysteresis for binary mixtures was examined by recording triplicate consecutive compression-expansion cycles. The lipid miscibility and membrane stability of DPPC/imidazolium lipids were subsequently evaluated by the excess mean molecular area (ΔAex) and the excess Gibbs free energy (ΔGex) of mixing. Furthermore, the thermotropic behavior of mixed liposomes of DPPC/imidazolium lipids was investigated by differential scanning calorimetry (DSC). The C15-imidazolium lipid (C15-IMe·HI) forms a thermodynamically favored and kinetically reversible Langmuir monolayer with DPPC and exhibits a rigidification effect on both DPPC monolayer and bilayer structures at low molar fractions (X ≤ 0.3). However, the incorporation of the C11-imidazolium lipid (C11-IMe·HI) causes the formation of an unstable and irreversible Langmuir-Gibbs monolayer with DPPC and disordered DPPC liposomes. The C7-imidazolium lipid (C7-IMe·HI) displays negligible membrane activity. To better understand these results on a molecular level, all-atom molecular dynamics (MD) simulations were performed. The simulations yield two opposing molecular mechanisms governing the different behavior of the three imidazolium lipids: a lateral ordering effect and a free volume/stretching effect. Overall, our study provides the first evidence that the membrane interaction of the C15 and C11 derivatives modulates the structural organization of lipid membranes. On the contrary, for the C7 derivative its membrane activity is too low to contribute to its earlier reported potent cytotoxicity.
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Affiliation(s)
- Da Wang
- Institut für Biochemie, ‡Institut für Physikalische Chemie, and §Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster , Wilhelm-Klemm-Straße 2, D-48149 Münster, Germany
| | - Djurre H de Jong
- Institut für Biochemie, ‡Institut für Physikalische Chemie, and §Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster , Wilhelm-Klemm-Straße 2, D-48149 Münster, Germany
| | - Andreas Rühling
- Institut für Biochemie, ‡Institut für Physikalische Chemie, and §Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster , Wilhelm-Klemm-Straße 2, D-48149 Münster, Germany
| | - Volker Lesch
- Institut für Biochemie, ‡Institut für Physikalische Chemie, and §Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster , Wilhelm-Klemm-Straße 2, D-48149 Münster, Germany
| | - Karina Shimizu
- Institut für Biochemie, ‡Institut für Physikalische Chemie, and §Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster , Wilhelm-Klemm-Straße 2, D-48149 Münster, Germany
| | - Stephanie Wulff
- Institut für Biochemie, ‡Institut für Physikalische Chemie, and §Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster , Wilhelm-Klemm-Straße 2, D-48149 Münster, Germany
| | - Andreas Heuer
- Institut für Biochemie, ‡Institut für Physikalische Chemie, and §Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster , Wilhelm-Klemm-Straße 2, D-48149 Münster, Germany
| | - Frank Glorius
- Institut für Biochemie, ‡Institut für Physikalische Chemie, and §Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster , Wilhelm-Klemm-Straße 2, D-48149 Münster, Germany
| | - Hans-Joachim Galla
- Institut für Biochemie, ‡Institut für Physikalische Chemie, and §Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster , Wilhelm-Klemm-Straße 2, D-48149 Münster, Germany
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7
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Deleu M, Crowet JM, Nasir MN, Lins L. Complementary biophysical tools to investigate lipid specificity in the interaction between bioactive molecules and the plasma membrane: A review. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2014; 1838:3171-3190. [DOI: 10.1016/j.bbamem.2014.08.023] [Citation(s) in RCA: 102] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2014] [Revised: 08/05/2014] [Accepted: 08/21/2014] [Indexed: 02/08/2023]
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8
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Lhor M, Bernier SC, Horchani H, Bussières S, Cantin L, Desbat B, Salesse C. Comparison between the behavior of different hydrophobic peptides allowing membrane anchoring of proteins. Adv Colloid Interface Sci 2014; 207:223-39. [PMID: 24560216 PMCID: PMC4028306 DOI: 10.1016/j.cis.2014.01.015] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2013] [Revised: 01/11/2014] [Accepted: 01/13/2014] [Indexed: 10/25/2022]
Abstract
Membrane binding of proteins such as short chain dehydrogenase reductases or tail-anchored proteins relies on their N- and/or C-terminal hydrophobic transmembrane segment. In this review, we propose guidelines to characterize such hydrophobic peptide segments using spectroscopic and biophysical measurements. The secondary structure content of the C-terminal peptides of retinol dehydrogenase 8, RGS9-1 anchor protein, lecithin retinol acyl transferase, and of the N-terminal peptide of retinol dehydrogenase 11 has been deduced by prediction tools from their primary sequence as well as by using infrared or circular dichroism analyses. Depending on the solvent and the solubilization method, significant structural differences were observed, often involving α-helices. The helical structure of these peptides was found to be consistent with their presumed membrane binding. Langmuir monolayers have been used as membrane models to study lipid-peptide interactions. The values of maximum insertion pressure obtained for all peptides using a monolayer of 1,2-dioleoyl-sn-glycero-3-phospho-ethanolamine (DOPE) are larger than the estimated lateral pressure of membranes, thus suggesting that they bind membranes. Polarization modulation infrared reflection absorption spectroscopy has been used to determine the structure and orientation of these peptides in the absence and in the presence of a DOPE monolayer. This lipid induced an increase or a decrease in the organization of the peptide secondary structure. Further measurements are necessary using other lipids to better understand the membrane interactions of these peptides.
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Affiliation(s)
- Mustapha Lhor
- CUO-Recherche, Centre de recherche du CHU de Québec, Hôpital du Saint-Sacrement, Département d'ophtalmologie, Faculté de médecine, Université Laval, Québec, Québec G1V 0A6, Canada; Regroupement stratégique PROTEO, Université Laval, Québec, Québec G1V 0A6, Canada
| | - Sarah C Bernier
- CUO-Recherche, Centre de recherche du CHU de Québec, Hôpital du Saint-Sacrement, Département d'ophtalmologie, Faculté de médecine, Université Laval, Québec, Québec G1V 0A6, Canada; Regroupement stratégique PROTEO, Université Laval, Québec, Québec G1V 0A6, Canada
| | - Habib Horchani
- CUO-Recherche, Centre de recherche du CHU de Québec, Hôpital du Saint-Sacrement, Département d'ophtalmologie, Faculté de médecine, Université Laval, Québec, Québec G1V 0A6, Canada; Regroupement stratégique PROTEO, Université Laval, Québec, Québec G1V 0A6, Canada
| | - Sylvain Bussières
- CUO-Recherche, Centre de recherche du CHU de Québec, Hôpital du Saint-Sacrement, Département d'ophtalmologie, Faculté de médecine, Université Laval, Québec, Québec G1V 0A6, Canada; Regroupement stratégique PROTEO, Université Laval, Québec, Québec G1V 0A6, Canada
| | - Line Cantin
- CUO-Recherche, Centre de recherche du CHU de Québec, Hôpital du Saint-Sacrement, Département d'ophtalmologie, Faculté de médecine, Université Laval, Québec, Québec G1V 0A6, Canada; Regroupement stratégique PROTEO, Université Laval, Québec, Québec G1V 0A6, Canada
| | - Bernard Desbat
- CBMN-UMR 5248 CNRS, Université de Bordeaux, IPB, Allée Geoffroy Saint Hilaire, 33600 Pessac, France
| | - Christian Salesse
- CUO-Recherche, Centre de recherche du CHU de Québec, Hôpital du Saint-Sacrement, Département d'ophtalmologie, Faculté de médecine, Université Laval, Québec, Québec G1V 0A6, Canada; Regroupement stratégique PROTEO, Université Laval, Québec, Québec G1V 0A6, Canada.
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9
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Imura T, Kawamura D, Taira T, Morita T, Fukuoka T, Aburai K, Sakai H, Abe M, Kitamoto D. Monolayer Behavior of Binary Systems of Lactonic and Acidic Forms of Sophorolipids: Thermodynamic Analyses of Langmuir Monolayers and AFM Study of Langmuir^|^ndash;Blodgett Monolayers. J Oleo Sci 2014; 63:67-73. [DOI: 10.5650/jos.ess13047] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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10
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Yang Y, Zou A, Song C, Mu B. Nanoscale Interfacial Activity of the Natural Lipopeptide, [Asp 1, Glu 5] Surfactin-C16, and DMPC in Mixed Monolayer. CHINESE J CHEM 2012. [DOI: 10.1002/cjoc.201200396] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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11
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Gang HZ, Liu JF, Mu BZ. Molecular Dynamics Study of Surfactin Monolayer at the Air/Water Interface. J Phys Chem B 2011; 115:12770-7. [DOI: 10.1021/jp206350j] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
- Hong-Ze Gang
- State Key Laboratory of Bioreactor Engineering and Institute of Applied Chemistry, East China University of Science and Technology, Shanghai, People's Republic of China 200237
| | - Jin-Feng Liu
- State Key Laboratory of Bioreactor Engineering and Institute of Applied Chemistry, East China University of Science and Technology, Shanghai, People's Republic of China 200237
| | - Bo-Zhong Mu
- State Key Laboratory of Bioreactor Engineering and Institute of Applied Chemistry, East China University of Science and Technology, Shanghai, People's Republic of China 200237
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Chièze L, Bolanos-Garcia VM, Pinot M, Desbat B, Renault A, Beaufils S, Vié V. Fluid and condensed ApoA-I/phospholipid monolayers provide insights into ApoA-I membrane insertion. J Mol Biol 2011; 410:60-76. [PMID: 21510960 DOI: 10.1016/j.jmb.2011.04.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2011] [Revised: 03/30/2011] [Accepted: 04/02/2011] [Indexed: 12/20/2022]
Abstract
Apolipoprotein A-I (ApoA-I) is a protein implicated in the solubilization of lipids and cholesterol from cellular membranes. The study of ApoA-I in phospholipid (PL) monolayers brings relevant information about ApoA-I/PL interactions. We investigated the influence of PL charge and acyl chain organization on the interaction with ApoA-I using dipalmitoyl-phosphatidylcholine, dioleoyl-phosphatidylcholine and dipalmitoyl-phosphatidylglycerol monolayers coupled to ellipsometric, surface pressure, atomic force microscopy and infrared (polarization modulation infrared reflection-absorption spectroscopy) measurements. We show that monolayer compressibility is the major factor controlling protein insertion into PL monolayers and show evidence of the requirement of a minimal distance between lipid headgroups for insertion to occur, Moreover, we demonstrate that ApoA-I inserts deepest at the highest compressibility of the protein monolayer and that the presence of an anionic headgroup increases the amount of protein inserted in the PL monolayer and prevents the steric constrains imposed by the spacing of the headgroup. We also defined the geometry of protein clusters into the lipid monolayer by atomic force microscopy and show evidence of the geometry dependence upon the lipid charge and the distance between headgroups. Finally, we show that ApoA-I helices have a specific orientation when associated to form clusters and that this is influenced by the character of PL charges. Taken together, our results suggest that the interaction of ApoA-I with the cellular membrane may be driven by a mechanism that resembles that of antimicrobial peptide/lipid interaction.
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Affiliation(s)
- Lionel Chièze
- Institut de Physique de Rennes, UMR-CNRS 6251 Université de Rennes 1, Campus de Beaulieu, 35042 Rennes cedex, France
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14
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El Kirat K, Morandat S, Dufrêne YF. Nanoscale analysis of supported lipid bilayers using atomic force microscopy. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2010; 1798:750-65. [DOI: 10.1016/j.bbamem.2009.07.026] [Citation(s) in RCA: 120] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2009] [Revised: 07/17/2009] [Accepted: 07/23/2009] [Indexed: 12/11/2022]
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15
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Boettcher C, Kell H, Holzwarth JF, Vater J. Flexible loops of thread-like micelles are formed upon interaction of L-alpha-dimyristoyl-phosphatidylcholine with the biosurfactant surfactin as revealed by cryo-electron tomography. Biophys Chem 2010; 149:22-7. [PMID: 20406718 DOI: 10.1016/j.bpc.2010.03.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2010] [Revised: 03/08/2010] [Accepted: 03/10/2010] [Indexed: 10/19/2022]
Abstract
Vesicles of L-alpha-dimyristoyl-phosphatidylcholine (DMPC) are known to disintegrate upon treatment with surfactin, a lipoheptapeptide biosurfactant from Bacillus subtilis OKB 105, as was observed by static light scattering (SLS) and cryo-transmission electron microscopy (cryo-TEM) recently. The lysis of DMPC bilayers occurs strongly dependent on the surfactin concentration according to a three-stage model. Unilamellar DMPC vesicles are disrupted to form sheet-like lamellar intermediates at a moderate surfactant concentration, but undergo a transition towards smaller particles of unknown structure at a higher surfactant concentration according to earlier neutron scattering experiments. Here we present direct structural evidence from cryo-electron tomography data that thread-like micelles with a uniform diameter of 6.5 nm are organized into loops of different sizes at a surfactin concentration of > 15 mol%.
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Affiliation(s)
- Christoph Boettcher
- Forschungszentrum für Elektronenmikroskopie, Institut für Chemie und Biochemie, Freie Universität Berlin, Fabeckstr. 36a, D-14195 Berlin, Germany.
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16
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Identification and characterization of a mosquito pupicidal metabolite of a Bacillus subtilis subsp. subtilis strain. Appl Microbiol Biotechnol 2010; 86:1737-44. [DOI: 10.1007/s00253-010-2449-y] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2009] [Revised: 01/08/2010] [Accepted: 01/12/2010] [Indexed: 10/19/2022]
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17
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Azouzi S, El Kirat K, Morandat S. The potent antimalarial drug cyclosporin A preferentially destabilizes sphingomyelin-rich membranes. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2010; 26:1960-1965. [PMID: 19697916 DOI: 10.1021/la902580w] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Cyclosporin A (CsA) is a hydrophobic cyclic peptide produced by a fungus. CsA is widely used as an immunosuppressive agent to inhibit the rejection of transplanted organs. CsA also exhibits an antiparasitic activity against Plasmodium, the microorganism responsible for malaria disease. This antimalarial activity is not completely understood yet. In this study, we have used Langmuir monolayers and atomic force microscopy to investigate the interaction of CsA with different lipids: phosphatidylcholines with different molecular packing, cholesterol, and sphingomyelin. We have shown that CsA inserts in all kinds of lipid monolayers but it has a marked preference for sphingomyelin monolayers. This preferential insertion of CsA within sphingomyelin-enriched membranes could explain the antimalarial activity of CsA. Indeed, the parasites need to produce a membrane network inside the erythrocytes, which allows for their proper development/multiplication by exchanging nutrients with the external medium. This membrane network is particularly enriched in sphingomyelin, so the preferential insertion of CsA in these bilayers may destabilize them, thereby inhibiting the development of the parasite.
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Affiliation(s)
- Slim Azouzi
- Laboratoire de Génie Enzymatique et Cellulaire, CNRS UMR 6022, 60205 Compiègne Cedex, France
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Hill K, Pénzes CB, Schnöller D, Horváti K, Bősze S, Hudecz F, Keszthelyi T, Kiss É. Characterisation of the membrane affinity of an isoniazide peptide conjugate by tensiometry, atomic force microscopy and sum-frequency vibrational spectroscopy, using a phospholipid Langmuir monolayer model. Phys Chem Chem Phys 2010; 12:11498-506. [DOI: 10.1039/c002737e] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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Nakahara H, Lee S, Shibata O. Pulmonary surfactant model systems catch the specific interaction of an amphiphilic peptide with anionic phospholipid. Biophys J 2009; 96:1415-29. [PMID: 19217859 DOI: 10.1016/j.bpj.2008.11.022] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2008] [Accepted: 11/20/2008] [Indexed: 10/21/2022] Open
Abstract
Interfacial behavior was studied in pulmonary surfactant model systems containing an amphiphilic alpha-helical peptide (Hel 13-5), which consists of 13 hydrophobic and five hydrophilic amino acid residues. Fully saturated phospholipids of dipalmitoylphosphatidylcholine (DPPC) and dipalmitoylphosphatidylglycerol (DPPG) were utilized to understand specific interactions between anionic DPPG and cationic Hel 13-5 for pulmonary functions. Surface pressure (pi)-molecular area (A) and surface potential (DeltaV)-A isotherms of DPPG/Hel 13-5 and DPPC/DPPG (4:1, mol/mol)/Hel 13-5 preparations were measured to obtain basic information on the phase behavior under compression and expansion processes. The interaction leads to a variation in squeeze-out surface pressures against a mole fraction of Hel 13-5, where Hel 13-5 is eliminated from the surface on compression. The phase behavior was visualized by means of Brewster angle microscopy, fluorescence microscopy, and atomic force microscopy. At low surface pressures, the formation of differently ordered domains in size and shape is induced by electrostatic interactions. The domains independently grow upon compression to high surface pressures, especially in the DPPG/Hel 13-5 system. Under the further compression process, protrusion masses are formed in AFM images in the vicinity of squeeze-out pressures. The protrusion masses, which are attributed to the squeezed-out Hel 13-5, grow larger in lateral size with increasing DPPG content in phospholipid compositions. During subsequent expansion up to 35 mN m(-1), the protrusions retain their height and lateral diameter for the DPPG/Hel 13-5 system, whereas the protrusions become smaller for the DPPC/Hel 13-5 and DPPC/DPPG/Hel 13-5 systems due to a reentrance of the ejected Hel 13-5 into the surface. In this work we detected for the first time, to our knowledge, a remarkably large hysteresis loop for cyclic DeltaV-A isotherms of the binary DPPG/Hel 13-5 preparation. This exciting phenomenon suggests that the specific interaction triggers two completely independent processes for Hel 13-5 during repeated compression and expansion: 1), squeezing-out into the subsolution; and 2), and close packing as a monolayer with DPPG at the interface. These characteristic processes are also strongly supported by atomic force microscopy observations. The data presented here provide complementary information on the mechanism and importance of the specific interaction between the phosphatidylglycerol headgroup and the polarized moiety of native surfactant protein B for biophysical functions of pulmonary surfactants.
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Affiliation(s)
- Hiromichi Nakahara
- Department of Biophysical Chemistry, Faculty of Pharmaceutical Sciences, Nagasaki International University, Nagasaki, Japan
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Aggregation behavior and surface morphology studies of surfactin in Langmuir–Blodgett films. Colloids Surf A Physicochem Eng Asp 2008. [DOI: 10.1016/j.colsurfa.2008.07.038] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Eeman M, Pegado L, Dufrêne YF, Paquot M, Deleu M. Influence of environmental conditions on the interfacial organisation of fengycin, a bioactive lipopeptide produced by Bacillus subtilis. J Colloid Interface Sci 2008; 329:253-64. [PMID: 18947831 DOI: 10.1016/j.jcis.2008.10.017] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2008] [Revised: 10/04/2008] [Accepted: 10/07/2008] [Indexed: 11/24/2022]
Abstract
The effect of the environmental conditions both on the behaviour of fengycin at the air-aqueous interface and on its interaction with DPPC was studied using surface pressure-area isotherms and AFM. The ionisation state of fengycin is at the origin of its monolayer interfacial properties. The most organised interfacial arrangement is obtained when fengycin behaves as if having zero net charge (pH 2). In a fully ionised state (pH 7.4), the organisation and the stability of fengycin monolayers depend on the ionic strength in the subphase. This can modulate the surface potential of fengycin and consequently the electrostatic repulsions inside the interfacial monolayer, as well as the lipopeptide interaction with the layer of water molecules forming the air-water interface. Intermolecular interactions of fengycin with DPPC are also strongly affected by the ionisation state of lipopeptide and the surface pressure (Pi) of the monolayer. A better miscibility between both interfacial components is observed at pH 2, while negatively charged lipopeptide molecules are segregated from the DPPC phase. A progressive desorption of fengycin from the interface is observed at pH 7.4 when Pi increases while at pH 2, fengycin desorption brutally occurs when Pi rises above Pi value of the intermediate plateau.
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Affiliation(s)
- Marc Eeman
- Unité de Chimie Biologique Industrielle, Faculté Universitaire des Sciences Agronomiques de Gembloux, Passage des Déportés, 2, B-5030 Gembloux, Belgium
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22
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Brasseur R, Deleu M, Mingeot-Leclercq MP, Francius G, Dufrêne YF. Probing peptide–membrane interactions using AFM. SURF INTERFACE ANAL 2008. [DOI: 10.1002/sia.2682] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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23
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Molecular behavior of a microbial lipopeptide monolayer at the air–water interface. Colloids Surf A Physicochem Eng Asp 2007. [DOI: 10.1016/j.colsurfa.2007.01.055] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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24
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Bouffioux O, Berquand A, Eeman M, Paquot M, Dufrêne YF, Brasseur R, Deleu M. Molecular organization of surfactin–phospholipid monolayers: Effect of phospholipid chain length and polar head. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2007; 1768:1758-68. [PMID: 17532292 DOI: 10.1016/j.bbamem.2007.04.015] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2006] [Revised: 04/19/2007] [Accepted: 04/20/2007] [Indexed: 11/26/2022]
Abstract
Mixed monolayers of the surface-active lipopeptide surfactin-C(15) and various lipids differing by their chain length (DMPC, DPPC, DSPC) and polar headgroup (DPPC, DPPE, DPPS) were investigated by atomic force microscopy (AFM) in combination with molecular modeling (Hypermatrix procedure) and surface pressure-area isotherms. In the presence of surfactin, AFM topographic images showed phase separation for each surfactin-phospholipid system except for surfactin-DMPC, which was in good agreement with compression isotherms. On the basis of domain shape and line tension theory, we conclude that the miscibility between surfactin and phospholipids is higher for shorter chain lengths (DMPC>DPPC>DSPC) and that the polar headgroup of phospholipids influences the miscibility of surfactin in the order DPPC>DPPE>DPPS. Molecular modeling data show that mixing surfactin and DPPC has a destabilizing effect on DPPC monolayer while it has a stabilizing effect towards DPPE and DPPS molecular interactions. Our results provide valuable information on the activity mechanism of surfactin and may be useful for the design of surfactin delivery systems.
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Affiliation(s)
- O Bouffioux
- Centre de Biophysique Moléculaire Numérique, Faculté Universitaire des Sciences Agronomiques de Gembloux, Passage des Déportés, 2, B-5030 Gembloux, Belgium
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25
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Kell H, Holzwarth JF, Boettcher C, Heenan RK, Vater J. Physicochemical studies of the interaction of the lipoheptapeptide surfactin with lipid bilayers of L-alpha-dimyristoyl phosphatidylcholine. Biophys Chem 2007; 128:114-24. [PMID: 17383076 DOI: 10.1016/j.bpc.2007.03.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2006] [Revised: 03/04/2007] [Accepted: 03/06/2007] [Indexed: 10/23/2022]
Abstract
To understand the biological action of surfactin from Bacillus subtilis we investigated its effects on the phase transition of L-alpha-dimyristoyl phosphatidylcholine (DMPC)-vesicles from the crystalline to the fluid state using differential scanning calorimetry; light scattering; small angle neutron scattering and cryo-electron microscopy. DSC-thermograms revealed two phase transition peaks. Light scattering profiles showed two branches with characteristic hysteresis phenomena. With both techniques the same values of the phase transition temperatures T(m1) and T(m2) of 23.5 and 23 degrees C were obtained indicating two forms of DMPC-surfactin aggregates which could be visualized by cryo-electron microscopy. Until 4 mol% surfactin the vesicular form predominated, but was accompanied by bilayered membrane fragments by increasing the biosurfactant concentrations. At surfactin concentrations higher than 15 mol% smaller DMPC-surfactin micelles of ellipsoidal conformation were formed, as demonstrated by small angle neutron scattering. In addition, by "Poor Man's" temperature-jump-relaxation spectroscopy slow transients in the phase transition of vesicular DMPC-surfactin aggregates with relaxation times of 20-30 s were detected which presumably indicate the slow dissipation of intermediate lipid-and surfactin domains formed after the main phase transition on the way to the fluid state. This process is accelerated by surfactin.
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Affiliation(s)
- Henny Kell
- Fritz-Haber-Institut, Max-Planck-Society, Faradayweg 4-6, D-14195 Berlin, Germany
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26
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Eeman M, Berquand A, Dufrêne YF, Paquot M, Dufour S, Deleu M. Penetration of surfactin into phospholipid monolayers: nanoscale interfacial organization. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2006; 22:11337-45. [PMID: 17154623 DOI: 10.1021/la061969p] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Atomic force microscopy (AFM) combined with surface pressure-area isotherms were used to probe the interfacial behavior of phospholipid monolayers following penetration of surfactin, a cyclic lipopeptide produced by Bacillus subtilis strains. Prior to penetration experiments, interfacial behavior of different surfactin molecules (cyclic surfactins with three different aliphatic chain lengths--S13, S14, and S15--and a linear surfactin obtained by chemical cleavage of the cycle of the surfactin S15) has been investigated. A more hydrophobic aliphatic chain induces greater surface-active properties of the lipopeptide. The opening of the peptide ring reduces the surface activity. The effect of phospholipid acyl chain length (dimyristoylphosphatidylcholine, dipalmitoylphosphatidylcholine- (DPPC), and distearoylphosphatidylcholine) and phospholipid polar head (DPPC, dipalmitoylphosphatidylethanolamine and dipalmitoylphosphatidylserine) on monolayer penetration properties of the surfactin S15 has been explored. Results showed that while the lipid monolayer thickness and the presence of electrostatic repulsions from the interfacial film do not significantly influence surfactin insertion, these parameters strongly modulate the ability of the surfactin to alter the nanoscale organization of the lipid films. We also probed the effect of surfactin structure (influence of the aliphatic chain length and of the cyclic structure of the peptide ring) on the behavior of DPPC monolayers. AFM images and isotherms showed that surfactin penetration is promoted by longer lipopeptide chain length and a cyclic polar head. This indicates that hydrophobic interactions are of main importance for the penetration power of surfactin molecules.
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Affiliation(s)
- M Eeman
- Unité de Chimie Biologique Industrielle, Faculté Universitaire des Sciences Agronomiques de Gembloux, Passage des Déportés 2, B-5030 Gembloux, Belgium
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Mateo-Martí E, Briones C, Román E, Briand E, Pradier CM, Martín-Gago JA. Self-assembled monolayers of peptide nucleic acids on gold surfaces: a spectroscopic study. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2005; 21:9510-7. [PMID: 16207029 DOI: 10.1021/la050366v] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
We have characterized self-assembled monolayers (SAMs) of thiol-derivatized peptide nucleic acid (PNA) chains adsorbed on gold surfaces by using reflection absorption infrared spectroscopy (RAIRS) and X-ray photoemission spectroscopy (XPS) techniques. We have found that the molecular orientation of PNAs strongly depends on surface coverage. At low coverage, PNA chains lie flat on the surface, while at high coverage, PNA molecules realign their molecular axes with the surface normal and form SAMs without the need of co-immobilization of spacers or other adjuvant molecules. The change in the molecular orientation has been studied by infrared spectroscopy and it has been confirmed by atomic force microscopy (AFM). PNA immobilization has been followed by analyzing the N(1s) XPS core-level peak. We show that the fine line shape of the N(1s) core-level peak at optimal concentration for biosensing is due to a chemical shift. A combination of the above-mentioned techniques allow us to affirm that the structure of the SAMs is stabilized by molecule-molecule interactions through noncomplementary adjacent nucleic bases.
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Affiliation(s)
- E Mateo-Martí
- Centro de Astrobiología (CSIC-INTA), Ctra. Ajalvir, Km. 4, 28850 Torrejón de Ardoz, Madrid, Spain
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Pedersen TB, Kaasgaard T, Jensen MØ, Frokjaer S, Mouritsen OG, Jørgensen K. Phase behavior and nanoscale structure of phospholipid membranes incorporated with acylated C14-peptides. Biophys J 2005; 89:2494-503. [PMID: 16100273 PMCID: PMC1366748 DOI: 10.1529/biophysj.105.060756] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2005] [Accepted: 07/05/2005] [Indexed: 11/18/2022] Open
Abstract
The thermotropic phase behavior and lateral structure of dipalmitoylphosphatidylcholine (DPPC) lipid bilayers containing an acylated peptide has been characterized by differential scanning calorimetry (DSC) on vesicles and atomic force microscopy (AFM) on mica-supported bilayers. The acylated peptide, which is a synthetic decapeptide N-terminally linked to a C14 acyl chain (C14-peptide), is incorporated into DPPC bilayers in amounts ranging from 0-20 mol %. The calorimetric scans of the two-component system demonstrate a distinct influence of the C14-peptide on the lipid bilayer thermodynamics. This is manifested as a concentration-dependent downshift of both the main phase transition and the pretransition. In addition, the main phase transition peak is significantly broadened, indicating phase coexistence. In the AFM imaging scans we found that the C14-peptide, when added to supported gel phase DPPC bilayers, inserts preferentially into preexisting defect regions and has a noticeable influence on the organization of the surrounding lipids. The presence of the C14-peptide gives rise to a laterally heterogeneous bilayer structure with coexisting lipid domains characterized by a 10 A height difference. The AFM images also show that the appearance of the ripple phase of the DPPC lipid bilayers is unaffected by the C14-peptide. The experimental results are supported by molecular dynamics simulations, which show that the C14-peptide has a disordering effect on the lipid acyl chains and causes a lateral expansion of the lipid bilayer. These effects are most pronounced for gel-like bilayer structures and support the observed downshift in the phase-transition temperature. Moreover, the molecular dynamics data indicate a tendency of a tryptophan residue in the peptide sequence to position itself in the bilayer headgroup region.
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Affiliation(s)
- Tina B Pedersen
- Department of Pharmaceutics, The Danish University of Pharmaceutical Sciences, DK-2100 Copenhagen Ø, Denmark
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Menezes Bento F, de Oliveira Camargo FA, Okeke BC, Frankenberger WT. Diversity of biosurfactant producing microorganisms isolated from soils contaminated with diesel oil. Microbiol Res 2005; 160:249-55. [PMID: 16035236 DOI: 10.1016/j.micres.2004.08.005] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Biosurfactant production is a desirable property of hydrocarbon-degrading microorganisms (HDM). We characterized biosurfactant producing microbial populations from a Long Beach soil, California (USA) and a Hong Kong soil (China), contaminated with diesel oil. A total of 33 hydrocarbon-utilizing microorganisms were isolated from the soils. Twelve isolates and three defined consortia were tested for biosurfactant production and emulsification activity. The highest reduction of surface tension was achieved with a consortium of L1, L2 and L3 isolates from a Long Beach soil (41.4mN m(-1)). Isolate L1 (Acinetobacter junii) displayed the highest reduction of surface tension (46.5 mN m(-1)). The emulsifying capacity evaluated by the E24 emulsification index was highest in the culture of isolate L5 (74%). No substantial emulsification was achieved with the cell-free extracts, indicating that the emulsifying activity was not extracellular. Based on surface tension and the E24 index results, isolates F1, F2, F3, F4, L1, L2, L3 and L4 were identified by 16S rRNA gene sequencing as Bacillus cereus, Bacillus sphaericus, B. fusiformis, Acinetobacter junii, a non-cultured bacterium, Pseudomonas sp. and B. pumilus, respectively. Cluster analyses of 16S rRNA gene sequences of the bacterial isolates revealed 70% similarity amongst hydrocarbon-degrading bacterial community present in both soils. Five isolates (isolates F1, F2, F3, F4 and L4) belong to the Firmicutes order, two isolates (L1 and L3) belong to the Proteobacteria order and one isolate (L2) is an Actinomyces sp. Simpson's index (1 - D) and the Shannon-Weaver index (H) revealed more diversity of HDM in the Hong Kong soil, while evenness (E) and the equitability (J) data indicated that there was not a dominant population. Bacterial isolates displaying substantial potential for production of biosurfactants can be applied in the bioremediation of soils contaminated with petroleum hydrocarbons.
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Affiliation(s)
- Fátima Menezes Bento
- Departament of Soils, University of Rio Grande Sul, Porto Alegre, CEP 91590-900, RS, Brazil
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30
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Cruz A, Vázquez L, Vélez M, Pérez-Gil J. Influence of a fluorescent probe on the nanostructure of phospholipid membranes: dipalmitoylphosphatidylcholine interfacial monolayers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2005; 21:5349-55. [PMID: 15924460 DOI: 10.1021/la046759w] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Monolayers of dipalmitoylphosphatidylcholine (DPPC), both in the absence and in the presence of 1% (mol/mol) of a fluorescent phospholipid probe, have been spread at the air-liquid interface of a surface balance, compressed up to pressures in the liquid-expanded/liquid-condensed plateau of the isotherm, transferred onto mica supports, and analyzed by scanning force microscopy (SFM). Supported DPPC films showed micrometer-sized condensed domains with morphology and size that were entirely analogous to those observed in situ at the air-liquid interface by epifluorescence microscopy. The analysis by SFM, however, allowed the study and comparison of monolayers in the absence and in the presence of the fluorescent marker. This analysis revealed that the presence of dye reduced by 10-20% the total amount of the liquid-condensed phase in the DPPC films. The presence of the dye also decreased the mechanical stability of the film and increased the time required for the monolayer to equilibrate. The resolution of SFM permitted the determination that the structures of both the liquid-expanded and the liquid-condensed regions of DPPC films were heterogeneous at the nanometer scale. Liquid-condensed DPPC microdomains contained nanoholes covering 4-8% of their area whereas 60-80% of the surface detected as liquid-expanded by fluorescence microscopy consisted of a condensed-like framework of nanodomains. The total area, the shape of the nanodomains, and their interconnectivity were affected by the presence of the probe, suggesting that care must be taken when studying the structure, especially at the nanometer scale, and properties of model lipid films in the presence of extrinsic probes.
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Affiliation(s)
- Antonio Cruz
- Departamento de Bioquímica, Facultad de Biología, Universidad Complutense de Madrid, 28040 Madrid, Spain
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31
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Liu X, Huang W, Wang E. An electrochemical study on the interaction of surfactin with a supported bilayer lipid membrane on a glassy carbon electrode. J Electroanal Chem (Lausanne) 2005. [DOI: 10.1016/j.jelechem.2004.12.010] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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32
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Eeman M, Deleu M, Paquot M, Thonart P, Dufrêne YF. Nanoscale properties of mixed fengycin/ceramide monolayers explored using atomic force microscopy. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2005; 21:2505-2511. [PMID: 15752046 DOI: 10.1021/la0475775] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
To gain insight into the interactions between fengycin and skin membrane lipids, mixed fengycin/ceramide monolayers were investigated using atomic force microscopy (AFM) (monolayers supported on mica) and surface pressure-area isotherms (monolayers at the air-water interface). AFM topographic images revealed phase separation in mixed monolayers prepared at 20 degrees C/pH 2 and composed of 0.25 and 0.5 fengycin molar ratios, in the form of two-dimensional (2-D) hexagonal crystalline domains of ceramide surrounded by a fengycin-enriched fluid phase. Surface pressure-area isotherms as well as friction and adhesion AFM images confirmed that the two phases had different molecular orientations: while ceramide formed a highly ordered phase with crystalline chain packing, fengycin exhibited a disordered fluid phase with the peptide ring lying horizontally on the substrate. Increasing the temperature and pH to values corresponding to the skin parameters, i.e., 37 degrees C/pH 5, was found to dramatically affect the film organization. At low fengycin molar ratio (0.25), the hexagonal ceramide domains transformed into round domains, while at higher ratio (0.5) these were shown to melt into a continuous fengycin/ceramide fluid phase. These observations were directly supported by the thermodynamic analysis (deviation from the additivity rule, excess of free energy) of the monolayer properties at the air-water interface. Accordingly, this study demonstrates that both the environmental conditions (temperature, pH) and fengycin concentration influence the molecular organization of mixed fengycin/ceramide monolayers. We believe that the ability to modulate the formation of 2-D domains in the skin membrane may be an important biological function of fengycin, which should be increasingly investigated in future pharmacological research.
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Affiliation(s)
- M Eeman
- Unité de Chimie Biologique Industrielle and Unité de Bio-industries, Faculté Universitaire des Sciences Agronomiques de Gembloux, Passage des Déportés, 2, B-5030 Gembloux, Belgium
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Lopes LB, Scarpa MV, Silva GVJ, Rodrigues DC, Santilli CV, Oliveira AG. Studies on the encapsulation of diclofenac in small unilamellar liposomes of soya phosphatidylcholine. Colloids Surf B Biointerfaces 2004; 39:151-8. [PMID: 15555896 DOI: 10.1016/j.colsurfb.2004.09.004] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2004] [Revised: 09/08/2004] [Accepted: 09/26/2004] [Indexed: 11/28/2022]
Abstract
The encapsulation of acid (AD) and sodium diclofenac (SD) in small unilamellar liposomes (SUV) as well as the interactions of the drug with the bilayer was studied. SUV was prepared by sonication from multilamellar liposomes containing soya phosphatidylcholine and diclofenac at various proportions. The size distribution obtained from dynamic light scattering showed that the incorporation of SD decreases significantly the size of the liposomes suggesting that the drug interacts with the bilayer of the liposomes. This size decrease is related with the phase transition of liposomes to mixed micelar solution. The encapsulation of the hydrophilic dye indocyanine green in the aqueous compartment of liposomes showed that the rate of captured dye decreases with SD concentration suggesting the transition of liposomes to mixed micelles. The (31)P NMR analysis indicates that SD interacts with the phosphate of phosphatidylcholine head groups. A schematic model for interaction of SD with phosphatidylcholine of the liposomes in which the diclofenac anion interacts with the ammonium group of the phospholipid and the dichlorophenyl ring occupies a more internal site of bilayer near phosphate group was proposed.
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Affiliation(s)
- L B Lopes
- Faculdade de Ciências Farmacêuticas, Universidade Estadual Paulista Júlio de Mesquita Filho, UNESP, Programa de Pós-graduação em Ciências Farmacêuticas, Rodovia Araraquara-Jaú, km 01, 14801-902 Araraquara, SP, Brazil
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Bosquillon C, Rouxhet PG, Ahimou F, Simon D, Culot C, Préat V, Vanbever R. Aerosolization properties, surface composition and physical state of spray-dried protein powders. J Control Release 2004; 99:357-67. [PMID: 15451594 DOI: 10.1016/j.jconrel.2004.07.022] [Citation(s) in RCA: 90] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2004] [Accepted: 07/14/2004] [Indexed: 10/26/2022]
Abstract
Powder aerosols made of albumin, dipalmitoylphosphatidylcholine (DPPC) and a protein stabilizer (lactose, trehalose or mannitol) were prepared by spray-drying and analyzed for aerodynamic behavior, surface composition and physical state. The powders exited a Spinhaler inhaler as particle aggregates, the size of which depending on composition, spray-drying parameters and airflow rate. However, due to low bulk powder tap density (<0.15 g/cm3), the aerodynamic size of a large fraction of aggregates remained respirable (<5 microm). Fine particle fractions ranged between 21% and 41% in an Andersen cascade impactor operated at 28.3 l/min, with mannitol and lactose providing the most cohesive and free-flowing powders, respectively. Particle surface analysis by X-ray photoelectron spectroscopy (XPS) revealed a surface enrichment with DPPC relative to albumin for powders prepared under certain spray-drying conditions. DPPC self-organized in a gel phase in the particle and no sugar or mannitol crystals were detected by X-ray diffraction. Water sorption isotherms showed that albumin protected lactose from moisture-induced crystallization. In conclusion, a proper combination of composition and spray-drying parameters allowed to obtain dry powders with elevated fine particle fractions (FPFs) and a physical environment favorable to protein stability.
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Affiliation(s)
- Cynthia Bosquillon
- Department of Pharmaceutical Technology, School of Pharmacy, Université catholique de Louvain, UCL 73.20 avenue E. Mounier, 73, 1200 Brussels, Belgium
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35
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Cruz A, Vázquez L, Vélez M, Pérez-Gil J. Effect of pulmonary surfactant protein SP-B on the micro- and nanostructure of phospholipid films. Biophys J 2004; 86:308-20. [PMID: 14695272 PMCID: PMC1303794 DOI: 10.1016/s0006-3495(04)74106-5] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
Monolayers of dipalmitoylphosphatidylcholine (DPPC) and DPPC/dipalmitoylphosphatidylglycerol (DPPG) (7:3, w/w) in the absence or in the presence of 2, 5, 10, or 20 weight percent of porcine surfactant protein SP-B were spread at the air-liquid interface of a surface balance, compressed up to surface pressures in the liquid-expanded/liquid-condensed (LE-LC) plateau of the isotherm, transferred onto mica supports, and analyzed by scanning force microscopy. In the absence of protein, the films showed micrometer-sized condensed domains with morphology and size that were analogous to those observed in situ at the air-liquid interface by epifluorescence microscopy. Scanning force microscopy permits examination of the coexisting phases at a higher resolution than previously achieved with fluorescent microscopy. Both LE and LC regions of DPPC films were heterogeneous in nature. LC microdomains contained numerous expanded-like islands whereas regions apparently liquid-expanded were covered by a condensed-like framework of interconnected nanodomains. Presence of increasing amounts of pulmonary surfactant protein SP-B affected the distribution of the LE and LC regions of DPPC and DPPC/DPPG films both at the microscopic and the nanoscopic level. The condensed microdomains became more numerous but their size decreased, resulting in an overall reduction of the amount of total LC phase in both DPPC and DPPC/DPPG films. At the nanoscopic level, SP-B also caused a marked reduction of the size of the condensed-like nanodomains in the LE phase and an increase in the length of the LE/LC interface. SP-B promotes a fine nanoscopic framework of lipid and lipid-protein nanodomains that is associated with a substantial mechanical resistance to film deformation and rupture as observed during film transference and manipulation. The effect of SP-B on the nanoscopic structure of the lipid films was greater in DPPC/DPPG than in pure DPPC films, indicating additional contributions of electrostatic lipid-protein interactions. The alterations of the nanoscopic structures of phospholipid films by SP-B provide the structural framework for the protein simultaneously sustaining structural stability as well as dynamical flexibility in surfactant films at the extreme conditions imposed by the respiratory mechanics. SP-B also formed segregated two-dimensional clusters that were associated with the boundaries between LC microdomains and the LE regions of DPPC and DPPC/DPPG films. The presence of these clusters at protein-to-lipid proportions above 2% by weight suggests that the concentration of SP-B in the surfactant lipid-protein complexes may be close to the solubility limit of the protein in the lipid films.
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Affiliation(s)
- Antonio Cruz
- Departamento de Bioquímica, Facultad de Biología, Universidad Complutense, 28040 Madrid, Spain
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36
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Souza SMB, Oliveira ON, Scarpa MV, Oliveira AG. Study of the diclofenac/phospholipid interactions with liposomes and monolayers. Colloids Surf B Biointerfaces 2004; 36:13-7. [PMID: 15261018 DOI: 10.1016/j.colsurfb.2004.05.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2004] [Revised: 04/19/2004] [Accepted: 05/03/2004] [Indexed: 11/25/2022]
Abstract
The interaction of diclofenac sodium (SD) with soya phosphatidylcholine (SPC) has been studied with floating Langmuir monolayers and liposomes. SD was either introduced into the subphase of SPC monolayers or co-spread with SPC on an aqueous subphase. In both cases, SD caused the surface pressure isotherm to become more expanded, thus demonstrating the affinity between SD and SPC. The incorporation of SD caused SPC liposomes to have a decreased diameter according to light scattering experiments. When SPC liposomes were injected into an aqueous subphase, their destruction yielding surface-active monomers could be monitored by changes in surface pressure. SD-loaded liposomes displayed a much faster kinetics when the surface density of surface-active monomers was plotted against time, with rate constants increasing significantly with the SD concentration. The kinetic profile can be quantitatively analyzed by plotting ln[1 - (gamma/gamma infinity)] versus t1/2.
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Affiliation(s)
- S M B Souza
- Faculdade de Ciências Farmacêuticas, Pesquisador recém-doutor do CNPq, Programa de Pós-graduação em Ciências Farmacêuticas, Unesp, Araraquara, SP, Brazil
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37
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Takizawa M, Kim YH, Urisu T. Deposition of DPPC monolayers by the Langmuir–Blodgett method on SiO2 surfaces covered by octadecyltrichlorosilane self-assembled monolayer islands. Chem Phys Lett 2004. [DOI: 10.1016/j.cplett.2003.11.112] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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38
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Wüstneck N, Wüstneck R, Perez-Gil J, Pison U. Effects of oligomerization and secondary structure on the surface behavior of pulmonary surfactant proteins SP-B and SP-C. Biophys J 2003; 84:1940-9. [PMID: 12609896 PMCID: PMC1302763 DOI: 10.1016/s0006-3495(03)75002-4] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The relationship among protein oligomerization, secondary structure at the interface, and the interfacial behavior was investigated for spread layers of native pulmonary surfactant associated proteins B and C. SP-B and SP-C were isolated either from butanol or chloroform/methanol lipid extracts that were obtained from sheep lung washings. The proteins were separated from other components by gel exclusion chromatography or by high performance liquid chromatography. SDS gel electrophoresis data indicate that the SP-B samples obtained using different solvents showed different oligomerization states of the protein. The CD and FTIR spectra of SP-B isolated from all extracts were consistent with a secondary structure dominated by alpha-helix. The CD and FTIR spectra of the first SP-C corresponded to an alpha-helical secondary structure and the spectra of the second SP-C corresponded to a mixture of alpha-helical and beta-sheet conformation. In contrast, the spectra of the third SP-C corresponded to antiparallel beta-sheets. The interfacial behavior was characterized by surface pressure/area (pi-A) isotherms. Differences in the oligomerization state of SP-B as well as in the secondary structure of SP-C all produce significant differences in the surface pressure/area isotherms. The molecular cross sections determined from the pi-A isotherms and from dynamic cycling experiments were 6 nm(2)/dimer molecule for SP-B and 1.15 nm(2)/molecule for SP-C in alpha-helical conformation and 1.05 nm(2)/molecule for SP-C in beta-sheet conformation. Both the oligomer ratio of SP-B and the secondary structure of SP-C strongly influence organization and behavior of these proteins in monolayer assemblies. In addition, alpha-helix --> beta-sheet conversion of SP-C occurs simply by an increase of the summary protein/lipid concentration in solution.
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Affiliation(s)
- N Wüstneck
- Humboldt-Universität Berlin, Charité Campus Virchow-Klinikum, Anaesthesiologie, Germany.
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Pelletier I, Bourque H, Buffeteau T, Blaudez D, Desbat B, Pézolet M. Study by Infrared Spectroscopy of Ultrathin Films of Behenic Acid Methyl Ester on Solid Substrates and at the Air/Water Interface. J Phys Chem B 2002. [DOI: 10.1021/jp012236a] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Isabelle Pelletier
- Centre de Recherche en Science et Ingénierie des Macromolécules, Département de Chimie, Université Laval, Québec, G1K 7P4, Canada, and Laboratoire de Physico-Chimie Moléculaire, UMR 5803 du CNRS, Université Bordeaux I, 33405 Talence, France, and Centre de Physique Moléculaire Optique et Hertzienne, UMR 5798 du CNRS, Université Bordeaux I, 33405 Talence, France
| | - Hélène Bourque
- Centre de Recherche en Science et Ingénierie des Macromolécules, Département de Chimie, Université Laval, Québec, G1K 7P4, Canada, and Laboratoire de Physico-Chimie Moléculaire, UMR 5803 du CNRS, Université Bordeaux I, 33405 Talence, France, and Centre de Physique Moléculaire Optique et Hertzienne, UMR 5798 du CNRS, Université Bordeaux I, 33405 Talence, France
| | - Thierry Buffeteau
- Centre de Recherche en Science et Ingénierie des Macromolécules, Département de Chimie, Université Laval, Québec, G1K 7P4, Canada, and Laboratoire de Physico-Chimie Moléculaire, UMR 5803 du CNRS, Université Bordeaux I, 33405 Talence, France, and Centre de Physique Moléculaire Optique et Hertzienne, UMR 5798 du CNRS, Université Bordeaux I, 33405 Talence, France
| | - Daniel Blaudez
- Centre de Recherche en Science et Ingénierie des Macromolécules, Département de Chimie, Université Laval, Québec, G1K 7P4, Canada, and Laboratoire de Physico-Chimie Moléculaire, UMR 5803 du CNRS, Université Bordeaux I, 33405 Talence, France, and Centre de Physique Moléculaire Optique et Hertzienne, UMR 5798 du CNRS, Université Bordeaux I, 33405 Talence, France
| | - Bernard Desbat
- Centre de Recherche en Science et Ingénierie des Macromolécules, Département de Chimie, Université Laval, Québec, G1K 7P4, Canada, and Laboratoire de Physico-Chimie Moléculaire, UMR 5803 du CNRS, Université Bordeaux I, 33405 Talence, France, and Centre de Physique Moléculaire Optique et Hertzienne, UMR 5798 du CNRS, Université Bordeaux I, 33405 Talence, France
| | - Michel Pézolet
- Centre de Recherche en Science et Ingénierie des Macromolécules, Département de Chimie, Université Laval, Québec, G1K 7P4, Canada, and Laboratoire de Physico-Chimie Moléculaire, UMR 5803 du CNRS, Université Bordeaux I, 33405 Talence, France, and Centre de Physique Moléculaire Optique et Hertzienne, UMR 5798 du CNRS, Université Bordeaux I, 33405 Talence, France
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Abstract
The introduction of functional imaging tools and techniques that operate at molecular-length scales has provided investigators with unique approaches to characterizing biomolecular structure and function relationships. Recent advances in the field of scanning probe techniques and, in particular, atomic force microscopy have yielded tantalizing insights into the dynamics of protein self-assembly and the mechanics of protein unfolding.
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Affiliation(s)
- C M Yip
- Department of Chemical Engineering, Institute of Biomaterials and Biomedical Engineering, University of Toronto, Ontario, Canada.
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Deleu M, Nott K, Brasseur R, Jacques P, Thonart P, Dufrêne YF. Imaging mixed lipid monolayers by dynamic atomic force microscopy. BIOCHIMICA ET BIOPHYSICA ACTA 2001; 1513:55-62. [PMID: 11427194 DOI: 10.1016/s0005-2736(01)00337-6] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Phase imaging with tapping mode atomic force microscopy (AFM) and force modulation microscopy were used to probe the mechanical properties of phase-separated lipid monolayers made of a mixture (0.25:0.75) of the surface-active lipopeptide surfactin and of dipalmitoylphosphatidylcholine (DPPC). The pi-A isotherms and the result of a molecular modeling study revealed a loose, 2-D liquid-like organization for the surfactin molecules and a closely packed, 2-D solid-like organization for DPPC molecules. This difference in molecular organization was responsible for a significant contrast in height, tapping mode phase and force modulation amplitude images. Phase imaging at light tapping, i.e., with a ratio of the set-point tapping amplitude with respect to the free amplitude A(sp)/A(0) approximately 0.9, showed larger phase shifts on the solid-like DPPC domains attributed to larger Young's modulus. However, contrast inversion was observed for A(sp)/A(0)<0.7, suggesting that at moderate and hard tapping the image contrast was dominated by the probe-sample contact area. Surprisingly, force modulation amplitude images showed larger stiffness for the liquid-like surfactin domains, suggesting that the contrast was dominated by contact area effects rather than by Young's modulus. These data emphasize the complex nature of the contrast mechanisms of dynamic AFM images recorded on mixed lipid monolayers.
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Affiliation(s)
- M Deleu
- Unité de Chimie Biologique Industrielle, Faculté Universitaire des Sciences Agronomiques de Gembloux, Belgium
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Vass E, Besson F, Majer Z, Volpon L, Hollósi M. Ca(2+)-induced changes of surfactin conformation: a FTIR and circular dichroism study. Biochem Biophys Res Commun 2001; 282:361-7. [PMID: 11264016 DOI: 10.1006/bbrc.2001.4469] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Previous NMR studies on surfactin proposed two gamma or beta-turn-containing conformers while recent CD studies described beta-sheets and alpha-helices in surfactin. Since these data were not obtained in the same conditions, the conformation of surfactin was reinvestigated by FTIR spectroscopy, a diagnostic method for beta-sheets. In trifluoroethanol, the FTIR spectra of surfactin and its diester are compatible with gamma and/or beta-turn(s) and the differences in their CD spectra show the importance of the Glu(1) and Asp(5) COOH groups in stabilizing the lipopeptide conformation. The calcium-induced spectral changes of both lipopeptides suggest a first binding of the divalent ions to the surfactin COOH groups (until calcium-lipopeptide mole ratio reached 1) followed by bulk conformational changes (at higher mole ratios). In Tris buffer at pH 8.5, the FTIR amide I band shape, without the typical 1610-1628 and 1675-1695 cm(-1) bands, ascertains the absence of beta-sheets.
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Affiliation(s)
- E Vass
- Department of Organic Chemistry, Eötvös Loránd University, Budapest, H-1518, Hungary
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Dufrêne YF, Lee GU. Advances in the characterization of supported lipid films with the atomic force microscope. BIOCHIMICA ET BIOPHYSICA ACTA 2000; 1509:14-41. [PMID: 11118515 DOI: 10.1016/s0005-2736(00)00346-1] [Citation(s) in RCA: 160] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
During the past decade, the atomic force microscope (AFM) has become a key technique in biochemistry and biophysics to characterize supported lipid films, as testified by the continuous growth in the number of papers published in the field. The unique capabilities of AFM are: (i) capacity to probe, in real time and in aqueous environment, the surface structure of lipid films; (ii) ability to directly measure physical properties at high spatial resolution; (iii) possibility to modify the film structure and biophysical processes in a controlled way. Such experiments, published up to June 2000, are the focus of the present review. First, we provide a general introduction on the preparation and characterization of supported lipid films as well as on the principles of AFM. The section 'Structural properties' focuses on the various applications of AFM for characterizing the structure of supported lipid films: visualization of molecular structure, formation of structural defects, effect of external agents, formation of supported films, organization of phase-separated films (coexistence region, mixed films) and, finally, the use of supported lipid bilayers for anchoring biomolecules such as DNA, enzymes and crystalline protein arrays. The section 'Physical properties' introduces the principles of force measurements by AFM, interpretation of these measurements and their recent application to supported lipid films and related structures. Finally, we highlight the major achievements brought by the technique and some of the current limitations.
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Affiliation(s)
- Y F Dufrêne
- Unité de chimie des interfaces, Université catholique de Louvain, Belgium.
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Abstract
The synthesis of extracellular molecules such as biosurfactants should have major consequences on bacterial adhesion. These molecules may be adsorbed on surfaces and modify their hydrophobicities. Certain strains of Bacillus subtilis synthesize the lipopeptides, which exhibit antibiotic and surface active properties. In this study the high-performance liquid chromatography (HPLC) analysis of the culture supernatants of the seven B. subtilis strains, showed that the lipopeptide profile varied greatly according to the strain. Among the three lipopeptide types, only iturin A was produced by all B. subtilis strains. Bacterial hydrophobicity, evaluated by the water contact angle measurements and the hydrophobic interaction chromatography, varied according to the strain. Two strains (ATCC 15476 and ATCC 15811) showing extreme behaviors in term of hydrophobicity were selected to study surfactin and iturin A effects on bacterial hydrophobicity. The two lipopeptides modified the B. subtilis surface hydrophobicity. Their effects varied according to the bacterial surface hydrophobic character, the lipopeptide type and the concentration. Lipopeptide adsorption increased the hydrophobicity of the hydrophilic strain but decreased that of the hydrophobic. Comparison of lipopeptide effects on B. subtilis surface hydrophobicity showed that surfactin was more effective than iturin A for the two strains tested.
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