Abdali, Salim

Engberts, Jan B.

Kuiper, Johanna M.

Lundbaek, Jens A.

Nielsen, Claus H.

Poolman, Bert

Tidemand-Lichtenberg, Peter

English

Proceedings - University of Groningen

   University of GroningenMechanical Pull On A Guest Molecule By A Photoresponsive Lipid BilayerLundbaek, Jens A.; Tidemand-Lichtenberg, Peter; Nielsen, Claus H.; Kuiper, Johanna M.;Engberts, Jan B.; Poolman, Bert; Abdali, SalimPublished in:EPRINTS-BOOK-TITLEIMPORTANT NOTE: You are advised to consult the publisher's version (publisher's PDF) if you wish to cite fromit. Please check the document version below.Document VersionPublisher's PDF, also known as Version of recordPublication date:2009Link to publication in University of Groningen/UMCG research databaseCitation for published version (APA):Lundbaek, J. A., Tidemand-Lichtenberg, P., Nielsen, C. H., Kuiper, J. M., Engberts, J. B., Poolman, B., &Abdali, S. (2009). Mechanical Pull On A Guest Molecule By A Photoresponsive Lipid Bilayer. In EPRINTS-BOOK-TITLE (pp. 151a-151a). University of Groningen, Stratingh Institute for Chemistry.CopyrightOther than for strictly personal use, it is not permitted to download or to forward/distribute the text or part of it without the consent of theauthor(s) and/or copyright holder(s), unless the work is under an open content license (like Creative Commons).The publication may also be distributed here under the terms of Article 25fa of the Dutch Copyright Act, indicated by the “Taverne” license.More information can be found on the University of Groningen website: https://www.rug.nl/library/open-access/self-archiving-pure/taverne-amendment.Take-down policyIf you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediatelyand investigate your claim.Downloaded from the University of Groningen/UMCG research database (Pure): http://www.rug.nl/research/portal. For technical reasons thenumber of authors shown on this cover page is limited to 10 maximum.Download date: 28-10-2022Sunday, March 1, 2009 151a776-Pos Board B655Plasma Membrane Area Increases With Spread Area By ExocytosisOf GPI Anchored Protein CompartmentNils C. Gauthier.Columbia University, New York, NY, USA.The mechanism by which cells control plasma membrane (PM) area is poorlyunderstood. Changes in PM area cannot arise from stretching the membrane.One possibility is that folds in the PM flatten out to follow shape changes.This model would predict that membrane tension increases and limit the shapechange induced by cell spreading. However, we found that PM tension decreasedduring spreading, indicating that PM area increased. Accordingly, exocytosis in-creased PM area by 40-60% during spreading. Moreover the increase in PM areawas proportional to the spread area. Golgi, lysosomes and glycosylphosphatidy-linositol-anchored protein vesicles (GPI vesicles) exocytosed during spreading,but no fusion of endoplasmic reticulum or transferrin receptor containing vesi-cles was detected. Microtubule depolymerization blocked lysosome and Golgiexocytosis, but not GPI vesicle exocytosis and PM area increase. We proposethat the dramatic increase in PM area during spreading originates selectivelyfrom a recycling pool of GPI-anchored protein vesicles.777-Pos Board B656Diffusion-Matched and Spectrally-Discrete Lipophilic Probes forNeuronal Tracing*Maria Hansen1, Jeff Tonniges1, Jeremy Duncan2, Matthew Bassett1,Bernd Fritzsch2, Brian Gray3, Michael Nichols1.1Creighton University, Omaha, NE, USA, 2University of Iowa, Iowa City, IA,USA, 3Molecular Targeting Technologies, Inc., West Chester, PA, USA.Lipophilic fluorescent dyes enable the tracing of neural networks by diffusinglaterally between nerve cell membranes. Because they do not require geneexpression for labeling, these dyes can be advantageous for studies of bothwild-type and mutant mice. To establish the neural connections that aremade during development, a diffusion-matched set of spectrally distinct dyesis needed. A set with green, red and far-red fluorescence emission have previ-ously been described [1]. Now, additional near-infrared and violet candidateshave been developed. To optimize sequential six-color imaging protocols, wehave measured the absolute multiphoton cross section spectra for these dyes.By combining two-photon and confocal microscopy, the entire set can be im-aged using a single Ti:S laser. In the environment of a peripheral nerve fiber,the diffusion characteristics of dyes with varied hydrocarbon chain lengthsand fluorescent head groups are determined by FRAP and distance measure-ments. By fitting the data to an anomalous-diffusion model, the time-scalingexponents and transport coefficients can be compared. Finally, we considerhow the mechanism of lipophilic dye transport in fixed and living cells canbe elucidated by transcellular diffusion from individually labeled cells withinan interconnected network.[1] H. Jensen-Smith et al., IMMUNOL. INVEST, 36(5-6): 763-789, 2007.* This work was supported by an N.I.H. SBIR II grant, R44 MH079805-04, andby P20 RR016475 from the INBRE Program of the National Center forResearch Resources.778-Pos Board B657Liposome Steady-state Anisotropy Of E.coli Total Lipid Extracts: A ToolTo Better Understand Antibiotic Translocation In A Bacterial Environ-mentJean-Philippe Borges, Carla Queiroz, Marcos Lovelle, Paula Gameiro.Requimte, University of Sciences, PORTO, Portugal.The outer membrane of Gram-negative bacteria is a protective diffusion bar-rier preventing the free entry of solutes into the periplasm. At the same time,the embedded proteins (Omp’s for Outer Membrane Proteins) fulfil a numberof tasks that are crucial to the bacterial cell, such as solute and protein trans-location, as well as signal transduction. Since a large number of years, a lotof simple membranar models with synthetic lipids such as POPC, POPG,DMPG..allowed scientists to better understand porin insertions and antibi-otic translocation/interaction. As any molecular phenomena, it is better tostudy it in their own environment. With the availability of well characterizedE.coli total lipid extract phospholipids, in vitro model membranes such asliposomes and proteoliposomes can be created and antibiotic translocationinvestigated in a bacterial environment, as close as possible to the existingmembranes.In this study, the effects of porins on the structural order of lipid membraneswas investigated by measuring, as a function of temperature, the steady-statefluorescence anisotropy (rS) of TMA-DPH and DPH incorporated into lipo-somes and proteoliposomes of E.coli total lipid extract phospholipids. DPH,embedded in the bilayer, can give informations about lipid diffusion.TMA-DPH, anchored at the aqueous interface of the phospholipid bilayer,allow us to better understand Omp’s/antibiotic interactions.By using those probes, we were able to obtain information on the effects causedby the insertion of Omp’s into the core and at the interface regions of the bila-yer. This information, correlated with other membrane models, can be ofconsiderable interest in establishing a possible relationship between the lipidcomposition of the phospholipid bilayer surface and antibiotic translocation.779-Pos Board B658Laurdan GP Fluctuations In Membranes Of Intact ErythrocytesSusana A. Sanchez, Enrico Gratton.Laboratory for Fluorescence Dynamics. Universitty of California at Irvine,Irvine, CA, USA.Lipids in the cell membranes are believed to be organized in micro-domains,known as rafts. If they in fact exist, rafts may provide important boundariesfor the organization and sequestering of membrane proteins. The prevailingtheory holds that membrane rafts are as small structures (10-200 nm), hetero-geneous in size, highly dynamic and sterol- and sphingolipid-enriched domainsthat compartmentalize cellular processes.The existence of these small domains is still under debate despite a great deal ofwork in the area. The most commonly used method to detect rafts is their resistanceto solubilization by the nonionic detergent Triton X-100 and sensitivity to choles-terol depletion. These measurements are indirect and potentially open to alterna-tive interpretations. Directly visualizing rafts in living cells has been a difficulttask because they are extremely small. Their existence still remains controversial.Here we report the use of a new methodology were two powerful microscopictechniques are applied simultaneously. The first technique, Laurdan General-ized polarization (GP), can differentiate liquid ordered phases from liquid dis-ordered phases based on the water content rather than on the partition propertiesof the probe. The second technique, Scanning Fluorescence Correlation Spec-troscopy quantifies the GP heterogeneities in the membranes. Using these tech-niques we observed GP fluctuations in the plasma membrane of rabbit red bloodcells that can be explained by a model that includes the existence of lipid micro-domains, which are heterogeneous in size and mobility. The properties of theseGP microdomains are similar to the proposed properties of rafts. Financial sup-port is provided by NIH RR03155.780-Pos Board B659Mechanical Pull On A Guest Molecule By A Photoresponsive Lipid BilayerJens A. Lundbaek1,2, Peter Tidemand-Lichtenberg1, Claus H. Nielsen1,Johanna M. Kuiper3, Jan B. Engberts3, Bert Poolman3, Salim Abdali1.1Department of Physics, Technical University of Denmark, Lyngby,Denmark, 2Weill Medical College of Cornell University, New York, NY,USA, 3Department of Biochemistry, University of Groningen, Groningen,Netherlands.One of the central challenges in nanotechnology is to develop tools for reversible,mechanical manipulation of non-covalently bound single molecules. Using thegramicidin (gA) channel, we demonstrate that light-induced changes in the me-chanical properties of a photoresponsive lipid bilayer allow for optical control ofthe bilayer disjoining force on a non-covalently bound guest molecule. The gAchannel is formed by trans-bilayer association of a monomer from each mono-layer in a lipid bilayer. Channel formation in a bilayer where the thickness ofthe bilayer hydrophobic core exceeds the channel length, involves a local bilayerthinning to match the channel. The bilayer, in response to the deformation, exertsa disjoining force on the channel - the magnitude of which is determined by thebilayer mechanical properties. We studied gA channels in 1,2-dioleoyl-sn-glyc-ero-3-phosphocholine (DOPC): di-(5-{[4-(4-butylphenyl)azo]phenoxy}pentyl(4-Azo-5P)/n-decane bilayers using single channel voltage clamp techniques.Upon exposure to UV light, the azobenzene moiety in the acyl chains of4-Azo-5P undergoes a reversible trans-to-cis isomerization, known alter the phys-ical properties of this lipid. By exposing gA channels in DOPC:4-Azo-5P bilayersto alternating visible or UV light, the bilayer disjoining force on the channel wasaltered such as to cause rapid, reversible changes in channel dissociation rate.781-Pos Board B660Study Of The Drug/lipid Interactions Between Cephalosporin AntibioticsAnd Liposomes By Complementary TechniquesMarcos Lovelle, Jean Philippe Borges, Paula Gameiro.REQUIMTE Facultade de Ciências do Porto, Porto, Portugal.The cephalosporins are bactericidal with both gram-positive and gram-negativeactivity widely prescribed because of their broad spectrum. Even though mostof these antibiotics appear to penetrate the outer membrane through porin pro-teins, we investigated, as a primary step, the interaction at the water-lipid inter-face. The information of the intrinsic property of these drugs in permeate orsimply interact with phospholipid bilayers becomes of great importance fora better understanding of the functions of a lipid component in the membrane

Mechanical Pull On A Guest Molecule By A Photoresponsive Lipid Bilayer

https://pure.rug.nl/ws/files/10388990/2009BiophysJLundbaek.pdf

Mechanical Pull On A Guest Molecule By A Photoresponsive Lipid Bilayer

Abstract

Similar works

Full text

Available Versions

Proceedings - University of Groningen