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  1. Article ; Online: Supramolecular structure in the membrane of Staphylococcus aureus.

    García-Lara, Jorge / Weihs, Felix / Ma, Xing / Walker, Lucas / Chaudhuri, Roy R / Kasturiarachchi, Jagath / Crossley, Howard / Golestanian, Ramin / Foster, Simon J

    Proceedings of the National Academy of Sciences of the United States of America

    2015  Volume 112, Issue 51, Page(s) 15725–15730

    Abstract: ... division. Here we present the discovery of a supramolecular structure in the membrane of the coccal ... bacterium Staphylococcus aureus, which leads to the formation of a large-scale pattern across the entire ... from the competition between the energy cost of bending that they impose on the membrane, their entropy of mixing, and ...

    Abstract All life demands the temporal and spatial control of essential biological functions. In bacteria, the recent discovery of coordinating elements provides a framework to begin to explain cell growth and division. Here we present the discovery of a supramolecular structure in the membrane of the coccal bacterium Staphylococcus aureus, which leads to the formation of a large-scale pattern across the entire cell body; this has been unveiled by studying the distribution of essential proteins involved in lipid metabolism (PlsY and CdsA). The organization is found to require MreD, which determines morphology in rod-shaped cells. The distribution of protein complexes can be explained as a spontaneous pattern formation arising from the competition between the energy cost of bending that they impose on the membrane, their entropy of mixing, and the geometric constraints in the system. Our results provide evidence for the existence of a self-organized and nonpercolating molecular scaffold involving MreD as an organizer for optimal cell function and growth based on the intrinsic self-assembling properties of biological molecules.
    MeSH term(s) Bacterial Proteins/analysis ; Cell Membrane/ultrastructure ; Entropy ; Lipid Metabolism ; Staphylococcus aureus/chemistry ; Staphylococcus aureus/metabolism ; Staphylococcus aureus/ultrastructure
    Chemical Substances Bacterial Proteins
    Language English
    Publishing date 2015-12-07
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 209104-5
    ISSN 1091-6490 ; 0027-8424
    ISSN (online) 1091-6490
    ISSN 0027-8424
    DOI 10.1073/pnas.1509557112
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    Zs.A 1148: Show issues Location:
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  2. Article ; Online: Cryo-EM-based structural insights into supramolecular assemblies of γ-hemolysin from S. aureus reveal the pore formation mechanism.

    Mishra, Suman / Roy, Anupam / Dutta, Somnath

    Structure (London, England : 1993)

    2023  Volume 31, Issue 6, Page(s) 651–667.e5

    Abstract: ... virulence factor from the Staphylococcus aureus Newman strain. In this study, we performed single-particle ... of octameric HlgAB pores on the membrane bilayer and an octahedral superassembly of octameric pore complexes ... in hydrophobic zipping between the rim domains of adjacent octameric complexes, providing additional structural ...

    Abstract γ-Hemolysin (γ-HL) is a hemolytic and leukotoxic bicomponent β-pore-forming toxin (β-PFT), a potent virulence factor from the Staphylococcus aureus Newman strain. In this study, we performed single-particle cryoelectron microscopy (cryo-EM) of γ-HL in a lipid environment. We observed clustering and square lattice packing of octameric HlgAB pores on the membrane bilayer and an octahedral superassembly of octameric pore complexes that we resolved at resolution of 3.5 Å. Our atomic model further demonstrated the key residues involved in hydrophobic zipping between the rim domains of adjacent octameric complexes, providing additional structural stability in PFTs post oligomerization. We also observed extra densities at the octahedral and octameric interfaces, providing insights into the plausible lipid-binding residues involved for HlgA and HlgB components. Furthermore, the hitherto elusive N-terminal region of HlgA was also resolved in our cryo-EM map, and an overall mechanism of pore formation for bicomponent β-PFTs is proposed.
    MeSH term(s) Hemolysin Proteins/chemistry ; Staphylococcus aureus ; Cryoelectron Microscopy ; Methicillin-Resistant Staphylococcus aureus ; Bacterial Toxins/chemistry ; Lipids
    Chemical Substances Hemolysin Proteins ; Bacterial Toxins ; Lipids
    Language English
    Publishing date 2023-04-04
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 1213087-4
    ISSN 1878-4186 ; 0969-2126
    ISSN (online) 1878-4186
    ISSN 0969-2126
    DOI 10.1016/j.str.2023.03.009
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    In stock of ZB MED Cologne/Königswinter

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    Je nach Verfügbarkeit (siehe Angabe bei Bestand)
    bis Jg. 1994: Bestellungen von Artikeln über das Online-Bestellformular
    Jg. 1995 - 2021: Lesesall (2.OG)
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  3. Article ; Online: Tunable nanostructures by directional assembly of donor-acceptor supramolecular copolymers and antibacterial activity.

    Chakraborty, Saptarshi / Barman, Ranajit / Ghosh, Suhrit

    Journal of materials chemistry. B

    2020  Volume 8, Issue 14, Page(s) 2909–2917

    Abstract: ... Contrastingly, their 1 : 1 mixture shows polymersome like assembly in which the membrane is constituted ... selectively against Gram positive bacteria. Mechanistic investigation indicated a membrane disruption pathway ... confirming their selective action against the bacterial membrane over the mammalian cell membrane. ...

    Abstract This manuscript reports supramolecular copolymerization of amphiphilic donor (D) and acceptor (A) units and their antibacterial activity. The donor unit (Py-1) contains a pyrene chromophore attached to a quaternary ammonium group by an amide linker. In the acceptor unit (NDI-1), a naphthalene-diimide (NDI) chromophore is attached to a hydrophilic non-ionic wedge and a benzamide group on its two opposite arms. In aqueous medium, Py-1 and NDI-1 produce micelle like nanoparticles and a fibrillar gel, respectively. Contrastingly, their 1 : 1 mixture shows polymersome like assembly in which the membrane is constituted of alternating D-A stacking stabilized by charge-transfer (CT) interactions and H-bonding among the amide groups. H-Bonding further gives unidirectional lateral orientation of the two chromophores and also regulates the direction of curvature so that all the cationic head groups are displayed on the exofacial polymersome surface. Such cationic D-A supramolecular polymersomes exhibit good bactericidal activity selectively against Gram positive bacteria over Gram negative bacteria. The spherical polymersome assembly gradually adopted a tubular morphology without disrupting the alternating D-A stacking mode, but it significantly reduced the antibacterial activity. By changing the D/A ratio, the surface charge density, hydrophobicity and morphology of the supramolecular copolymers could be tuned systemically, which had a strong impact on the antibacterial activity and selectivity. Addition of 5-10 mol% of NDI-1 to Py-1 changed the morphology from nanoparticles to polymersomes with the most optimized combination of cationic charge density and hydrophobicity, which resulted in producing a lethal antibacterial system (MIC value 16 μg mL-1) selectively against Gram positive bacteria. Mechanistic investigation indicated a membrane disruption pathway of cell killing. No combination of Py-1 and NDI-1 exhibited hemolysis activity up to 1000 μg mL-1 confirming their selective action against the bacterial membrane over the mammalian cell membrane.
    MeSH term(s) Anti-Bacterial Agents/chemical synthesis ; Anti-Bacterial Agents/chemistry ; Anti-Bacterial Agents/pharmacology ; Escherichia coli/drug effects ; Macromolecular Substances/chemical synthesis ; Macromolecular Substances/chemistry ; Macromolecular Substances/pharmacology ; Microbial Sensitivity Tests ; Molecular Structure ; Nanostructures/chemistry ; Particle Size ; Polymers/chemical synthesis ; Polymers/chemistry ; Polymers/pharmacology ; Staphylococcus aureus/drug effects ; Surface Properties
    Chemical Substances Anti-Bacterial Agents ; Macromolecular Substances ; Polymers
    Language English
    Publishing date 2020-03-19
    Publishing country England
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 2702241-9
    ISSN 2050-7518 ; 2050-750X
    ISSN (online) 2050-7518
    ISSN 2050-750X
    DOI 10.1039/c9tb02772f
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  4. Article ; Online: Supramolecular amphipathicity for probing antimicrobial propensity of host defence peptides.

    Ravi, Jascindra / Bella, Angelo / Correia, Ana J V / Lamarre, Baptiste / Ryadnov, Maxim G

    Physical chemistry chemical physics : PCCP

    2015  Volume 17, Issue 24, Page(s) 15608–15614

    Abstract: ... toxic to microbial membranes. Here we explore the concept of supramolecular amphipathicity for probing ... to the orthogonal type of their primary structure. The study demonstrates that inducible supramolecular ... inactive, but when ordered into microscopic micellar assemblies, respond to membrane binding according ...

    Abstract Host defence peptides (HDPs) are effector components of innate immunity that provide defence against pathogens. These are small-to-medium sized proteins which fold into amphipathic conformations toxic to microbial membranes. Here we explore the concept of supramolecular amphipathicity for probing antimicrobial propensity of HDPs using elementary HDP-like amphiphiles. Such amphiphiles are individually inactive, but when ordered into microscopic micellar assemblies, respond to membrane binding according to the orthogonal type of their primary structure. The study demonstrates that inducible supramolecular amphipathicity can discriminate against bacterial growth and colonisation thereby offering a physico-chemical rationale for tuneable targeting of biological membranes.
    MeSH term(s) Animals ; Anti-Bacterial Agents/chemical synthesis ; Anti-Bacterial Agents/chemistry ; Anti-Bacterial Agents/pharmacology ; Antimicrobial Cationic Peptides/chemical synthesis ; Antimicrobial Cationic Peptides/chemistry ; Antimicrobial Cationic Peptides/pharmacology ; Cattle ; Dose-Response Relationship, Drug ; Erythrocytes/drug effects ; Escherichia coli/cytology ; Escherichia coli/drug effects ; Escherichia coli/growth & development ; Hemolysis/drug effects ; Humans ; Microbial Sensitivity Tests ; Pseudomonas aeruginosa/cytology ; Pseudomonas aeruginosa/drug effects ; Pseudomonas aeruginosa/growth & development ; Staphylococcus aureus/cytology ; Staphylococcus aureus/drug effects ; Staphylococcus aureus/growth & development ; Structure-Activity Relationship
    Chemical Substances Anti-Bacterial Agents ; Antimicrobial Cationic Peptides
    Language English
    Publishing date 2015-06-28
    Publishing country England
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 1476244-4
    ISSN 1463-9084 ; 1463-9076
    ISSN (online) 1463-9084
    ISSN 1463-9076
    DOI 10.1039/c5cp01185j
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  5. Article: Directional Supramolecular Assembly of π-Amphiphiles with Tunable Surface Functionality and Impact on the Antimicrobial Activity

    Sikder, Amrita / Sarkar, Jayita / Barman, Ranajit / Ghosh, Suhrit

    Journal of physical chemistry. 2019 July 26, v. 123, no. 33

    2019  

    Abstract: ... of the structure of the head group on the interaction with the model membrane. In fact, in all cases ... with very low minimum inhibitory concentration values of 15.8 and 62 μg/mL for Staphylococcus aureus and ... studies revealed the spontaneous interaction of NDI-2 assembly with bacteria membrane mimic DPPE liposome ...

    Abstract This article elucidates H-bonding-regulated directional supramolecular assembly of naphthalene diimide (NDI)-derived unsymmetric cationic bola-shaped π-amphiphiles and systematic investigations on the thermodynamics of their interaction with bacteria mimic lipid vesicles and antimicrobial activity with mechanistic insights. Four NDI-amphiphiles (NDI-1, NDI-2, NDI-3, and NDI-2a) have been studied, all of which contain a central NDI chromophore, a nonionic wedge, an amine containing a head group, and a hydrazide group. In NDI-2 and NDI-2a, the hydrophilic wedge and the head group (pyridine) are the same but the location of the hydrazide group is different. On the basis of this difference, the pyridyl groups are displayed at the outer and inner walls of the vesicle, respectively. Isothermal titration calorimetry (ITC) studies revealed the spontaneous interaction of NDI-2 assembly with bacteria membrane mimic DPPE liposome (ΔG = −6.35 kcal/mol), whereas the NDI-2a assembly did not interact at all, confirming a strong influence of the H-bonding-regulated functional group display. On the other hand, the location of the hydrazide group remains the same in NDI-1, NDI-2, and NDI-3, but they differ in the head group structure. ITC binding studies confirmed spontaneous interaction of all three assemblies with DPPE liposome with negative ΔG values following the order NDI-1 > NDI-2 > NDI-3, indicating significant influence of the structure of the head group on the interaction with the model membrane. In fact, in all cases, the interaction was favorable both by enthalpy and entropy contribution, indicating dual involvement of the electrostatic interaction and hydrophobic effect. Notably, ΔS value for NDI-1 containing a tertiary amine head group was found to be significantly higher than that for NDI-3 containing a primary amine, which is attributed to the enhanced hydrophobic effect in the former case. Furthermore, ITC experiments revealed no interaction by any of these assemblies with the mammalian cell membrane mimic liposome, indicating their high selectivity toward bacterial membranes. Antimicrobial activity studies showed NDI-2 to be lethal selectively against Gram-positive bacteria, whereas NDI-2a did not show any activity. NDI-3 with a primary amine showed moderate activity but no selectivity over the erythrocytes. NDI-1 with the tertiary amine group was found to be the most outstanding candidate, exhibiting broad-spectrum antimicrobial activity with very low minimum inhibitory concentration values of 15.8 and 62 μg/mL for Staphylococcus aureus and Escherichia coli, respectively, and high selectivity over erythrocytes. These results fully corroborate with the physical insights obtained from the ITC studies on their interaction with the model liposome. Control molecules, lacking either the NDI chromophore or the hydrazide nonionic containing wedge, did not exhibit any notable antibacterial activity. Live-dead assay with fluorescence microscopy studies indicated that the antimicrobial activity of NDI-1 operates through the membrane disruption pathway similar to that of the host defense peptides.
    Keywords Escherichia coli ; Gram-positive bacteria ; Staphylococcus aureus ; antibacterial properties ; calorimetry ; cell membranes ; electrostatic interactions ; enthalpy ; entropy ; erythrocytes ; fluorescence microscopy ; hydrazides ; hydrophilicity ; hydrophobicity ; lipids ; mammals ; minimum inhibitory concentration ; models ; moieties ; naphthalene ; peptides ; pyridines ; titration
    Language English
    Dates of publication 2019-0726
    Size p. 7169-7177.
    Publishing place American Chemical Society
    Document type Article
    ISSN 1520-5207
    DOI 10.1021/acs.jpcb.9b05193
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  6. Article ; Online: Structural and thermodynamic characterization of doxycycline/β-cyclodextrin supramolecular complex and its bacterial membrane interactions.

    Suárez, Diego F / Consuegra, Jessika / Trajano, Vivianne C / Gontijo, Sávio M L / Guimarães, Pedro P G / Cortés, Maria E / Denadai, Ângelo L / Sinisterra, Rubén D

    Colloids and surfaces. B, Biointerfaces

    2014  Volume 118, Page(s) 194–201

    Abstract: ... between DOX and the membrane of S. aureus. In addition, the adhesion of βCD to the cell membrane via ... investigated, as well as their interactions and effects on Staphylococcus aureus cells and cellular ... a low equilibrium constant was obtained. Treatment of S. aureus with higher concentrations of DOX or DOX ...

    Abstract Doxycycline is a semi-synthetic antibiotic commonly used for the treatment of many aerobic and anaerobic bacteria. It inhibits the activity of matrix metalloproteinases (MMPs) and affects cell proliferation. In this study, the structural and thermodynamic parameters of free DOX and a DOX/βCD complex were investigated, as well as their interactions and effects on Staphylococcus aureus cells and cellular cytotoxicity. Complexation of DOX and βCD was confirmed to be an enthalpy- and entropy-driven process, and a low equilibrium constant was obtained. Treatment of S. aureus with higher concentrations of DOX or DOX/βCD resulted in an exponential decrease in S. aureus cell size, as well as a gradual neutralization of zeta potential. These thermodynamic profiles suggest that ion-pairing and hydrogen bonding interactions occur between DOX and the membrane of S. aureus. In addition, the adhesion of βCD to the cell membrane via hydrogen bonding is hypothesized to mediate a synergistic effect which accounts for the higher activity of DOX/βCD against S. aureus compared to pure DOX. Lower cytotoxicity and induction of osteoblast proliferation was also associated with DOX/βCD compared with free DOX. These promising findings demonstrate the potential for DOX/βCD to mediate antimicrobial activity at lower concentrations, and provides a strategy for the development of other antimicrobial formulations.
    MeSH term(s) Animals ; Calorimetry ; Cell Death/drug effects ; Cell Membrane/drug effects ; Cell Proliferation/drug effects ; Differential Thermal Analysis ; Doxycycline/chemistry ; Doxycycline/pharmacology ; Hydrodynamics ; Light ; Magnetic Resonance Spectroscopy ; Microbial Sensitivity Tests ; Osteoblasts/cytology ; Osteoblasts/drug effects ; Osteoblasts/metabolism ; Proton Magnetic Resonance Spectroscopy ; Rats, Wistar ; Scattering, Radiation ; Spectroscopy, Fourier Transform Infrared ; Staphylococcus aureus/cytology ; Staphylococcus aureus/drug effects ; Static Electricity ; Thermodynamics ; Thermogravimetry ; beta-Cyclodextrins/chemistry ; beta-Cyclodextrins/pharmacology
    Chemical Substances beta-Cyclodextrins ; betadex (JV039JZZ3A) ; Doxycycline (N12000U13O)
    Language English
    Publishing date 2014-06-01
    Publishing country Netherlands
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 1500523-9
    ISSN 1873-4367 ; 0927-7765
    ISSN (online) 1873-4367
    ISSN 0927-7765
    DOI 10.1016/j.colsurfb.2014.01.028
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  7. Article: Structural and thermodynamic characterization of doxycycline/β-cyclodextrin supramolecular complex and its bacterial membrane interactions

    Suárez, Diego F / Ângelo L. Denadai / Jessika Consuegra / Maria E. Cortés / Pedro P.G. Guimarães / Rubén D. Sinisterra / Sávio M.L. Gontijo / Vivianne C. Trajano

    Colloids and Surfaces B: Biointerfaces. 2014 June 01, v. 118

    2014  

    Abstract: ... interactions occur between DOX and the membrane of S. aureus. In addition, the adhesion of βCD ... were investigated, as well as their interactions and effects on Staphylococcus aureus cells and ... process, and a low equilibrium constant was obtained. Treatment of S. aureus with higher concentrations ...

    Abstract Doxycycline is a semi-synthetic antibiotic commonly used for the treatment of many aerobic and anaerobic bacteria. It inhibits the activity of matrix metalloproteinases (MMPs) and affects cell proliferation. In this study, the structural and thermodynamic parameters of free DOX and a DOX/βCD complex were investigated, as well as their interactions and effects on Staphylococcus aureus cells and cellular cytotoxicity. Complexation of DOX and βCD was confirmed to be an enthalpy- and entropy-driven process, and a low equilibrium constant was obtained. Treatment of S. aureus with higher concentrations of DOX or DOX/βCD resulted in an exponential decrease in S. aureus cell size, as well as a gradual neutralization of zeta potential. These thermodynamic profiles suggest that ion-pairing and hydrogen bonding interactions occur between DOX and the membrane of S. aureus. In addition, the adhesion of βCD to the cell membrane via hydrogen bonding is hypothesized to mediate a synergistic effect which accounts for the higher activity of DOX/βCD against S. aureus compared to pure DOX. Lower cytotoxicity and induction of osteoblast proliferation was also associated with DOX/βCD compared with free DOX. These promising findings demonstrate the potential for DOX/βCD to mediate antimicrobial activity at lower concentrations, and provides a strategy for the development of other antimicrobial formulations.
    Keywords adhesion ; antibacterial properties ; bacteria ; cell membranes ; cell proliferation ; colloids ; cytotoxicity ; doxycycline ; hydrogen bonding ; metalloproteinases ; neutralization ; osteoblasts ; Staphylococcus aureus ; synergism ; thermodynamics ; zeta potential
    Language English
    Dates of publication 2014-0601
    Size p. 194-201.
    Publishing place Elsevier B.V.
    Document type Article
    ZDB-ID 1500523-9
    ISSN 1873-4367 ; 0927-7765
    ISSN (online) 1873-4367
    ISSN 0927-7765
    DOI 10.1016/j.colsurfb.2014.01.028
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