Relevant bibliographies by topics / Model lipid membrane

Academic literature on the topic 'Model lipid membrane'

Author: Grafiati
Published: 9 March 2023
Last updated: 10 March 2023

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles

Select a source type:

Contents

Consult the lists of relevant articles, books, theses, conference reports, and other scholarly sources on the topic 'Model lipid membrane.'

Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.

You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.

Journal articles on the topic "Model lipid membrane"

1

Nicolson, Garth L., and Gonzalo Ferreira de Mattos. "A Brief Introduction to Some Aspects of the Fluid–Mosaic Model of Cell Membrane Structure and Its Importance in Membrane Lipid Replacement." Membranes 11, no. 12 (November 29, 2021): 947. http://dx.doi.org/10.3390/membranes11120947.

Full text
Abstract:
Early cell membrane models placed most proteins external to lipid bilayers in trimolecular structures or as modular lipoprotein units. These thermodynamically untenable structures did not allow lipid lateral movements independent of membrane proteins. The Fluid–Mosaic Membrane Model accounted for these and other properties, such as membrane asymmetry, variable lateral mobilities of membrane components and their associations with dynamic complexes. Integral membrane proteins can transform into globular structures that are intercalated to various degrees into a heterogeneous lipid bilayer matrix. This simplified version of cell membrane structure was never proposed as the ultimate biomembrane description, but it provided a basic nanometer scale framework for membrane organization. Subsequently, the structures associated with membranes were considered, including peripheral membrane proteins, and cytoskeletal and extracellular matrix components that restricted lateral mobility. In addition, lipid–lipid and lipid–protein membrane domains, essential for cellular signaling, were proposed and eventually discovered. The presence of specialized membrane domains significantly reduced the extent of the fluid lipid matrix, so membranes have become more mosaic with some fluid areas over time. However, the fluid regions of membranes are very important in lipid transport and exchange. Various lipid globules, droplets, vesicles and other membranes can fuse to incorporate new lipids or expel damaged lipids from membranes, or they can be internalized in endosomes that eventually fuse with other internal vesicles and membranes. They can also be externalized in a reverse process and released as extracellular vesicles and exosomes. In this Special Issue, the use of membrane phospholipids to modify cellular membranes in order to modulate clinically relevant host properties is considered.
APA, Harvard, Vancouver, ISO, and other styles
2

Nicolson, Garth L., and Gonzalo Ferreira de Mattos. "Fifty Years of the Fluid–Mosaic Model of Biomembrane Structure and Organization and Its Importance in Biomedicine with Particular Emphasis on Membrane Lipid Replacement." Biomedicines 10, no. 7 (July 15, 2022): 1711. http://dx.doi.org/10.3390/biomedicines10071711.

Full text
Abstract:
The Fluid–Mosaic Model has been the accepted general or basic model for biomembrane structure and organization for the last 50 years. In order to establish a basic model for biomembranes, some general principles had to be established, such as thermodynamic assumptions, various molecular interactions, component dynamics, macromolecular organization and other features. Previous researchers placed most membrane proteins on the exterior and interior surfaces of lipid bilayers to form trimolecular structures or as lipoprotein units arranged as modular sheets. Such membrane models were structurally and thermodynamically unsound and did not allow independent lipid and protein lateral movements. The Fluid–Mosaic Membrane Model was the only model that accounted for these and other characteristics, such as membrane asymmetry, variable lateral movements of membrane components, cis- and transmembrane linkages and dynamic associations of membrane components into multimolecular complexes. The original version of the Fluid–Mosaic Membrane Model was never proposed as the ultimate molecular description of all biomembranes, but it did provide a basic framework for nanometer-scale biomembrane organization and dynamics. Because this model was based on available 1960s-era data, it could not explain all of the properties of various biomembranes discovered in subsequent years. However, the fundamental organizational and dynamic aspects of this model remain relevant to this day. After the first generation of this model was published, additional data on various structures associated with membranes were included, resulting in the addition of membrane-associated cytoskeletal, extracellular matrix and other structures, specialized lipid–lipid and lipid–protein domains, and other configurations that can affect membrane dynamics. The presence of such specialized membrane domains has significantly reduced the extent of the fluid lipid membrane matrix as first proposed, and biomembranes are now considered to be less fluid and more mosaic with some fluid areas, rather than a fluid matrix with predominantly mobile components. However, the fluid–lipid matrix regions remain very important in biomembranes, especially those involved in the binding and release of membrane lipid vesicles and the uptake of various nutrients. Membrane phospholipids can associate spontaneously to form lipid structures and vesicles that can fuse with various cellular membranes to transport lipids and other nutrients into cells and organelles and expel damaged lipids and toxic hydrophobic molecules from cells and tissues. This process and the clinical use of membrane phospholipid supplements has important implications for chronic illnesses and the support of healthy mitochondria, plasma membranes and other cellular membrane structures.
APA, Harvard, Vancouver, ISO, and other styles
3

Scott, Haden L., Kristen B. Kennison, Thais A. Enoki, Milka Doktorova, Jacob J. Kinnun, Frederick A. Heberle, and John Katsaras. "Model Membrane Systems Used to Study Plasma Membrane Lipid Asymmetry." Symmetry 13, no. 8 (July 26, 2021): 1356. http://dx.doi.org/10.3390/sym13081356.

Full text
Abstract:
It is well known that the lipid distribution in the bilayer leaflets of mammalian plasma membranes (PMs) is not symmetric. Despite this, model membrane studies have largely relied on chemically symmetric model membranes for the study of lipid–lipid and lipid–protein interactions. This is primarily due to the difficulty in preparing stable, asymmetric model membranes that are amenable to biophysical studies. However, in the last 20 years, efforts have been made in producing more biologically faithful model membranes. Here, we review several recently developed experimental and computational techniques for the robust generation of asymmetric model membranes and highlight a new and particularly promising technique to study membrane asymmetry.
APA, Harvard, Vancouver, ISO, and other styles
4

Wang, Anna, and Jack W. Szostak. "Lipid constituents of model protocell membranes." Emerging Topics in Life Sciences 3, no. 5 (July 15, 2019): 537–42. http://dx.doi.org/10.1042/etls20190021.

Full text
Abstract:
Primitive life must have possessed the essential features of modern cellular life, but without highly evolved proteins to perform dynamic functions such as nutrient transport and membrane remodeling. Here, we consider the membrane properties of protocells — minimal cells with hereditary material, capable of growth and division — and how these properties place restrictions on the components of the membrane. For example, the lipids of modern membranes are diacyl amphiphilic molecules containing well-over 20 carbons in total. Without proteins, these membranes are very stable and kinetically trapped. This inertness, combined with the need for enzymes to synthesize them, makes modern diacyl amphiphiles unsuitable candidates for the earliest membranes on Earth. We, therefore, discuss the progress made thus far with single-chained amphiphiles, including fatty acids and mixtures of fatty acids with related molecules, and the membrane-related research that must be undertaken to gain more insight into the origins of cellular life.
APA, Harvard, Vancouver, ISO, and other styles
5

Duda, Mariusz, Katarzyna Kawula, Anna Pawlak, Tadeusz Sarna, and Anna Wisniewska-Becker. "EPR Studies on the Properties of Model Photoreceptor Membranes Made of Natural and Synthetic Lipids." Cell Biochemistry and Biophysics 75, no. 3-4 (April 17, 2017): 433–42. http://dx.doi.org/10.1007/s12013-017-0795-4.

Full text
Abstract:
Abstract The membranes of retina photoreceptors have unique lipid composition. They contain a high concentration of polyunsaturated docosahexaenoic acid, with six double bonds, and are enriched in phosphatidylethanolamines. Based on their phospholipid composition and cholesterol content, membranes of photoreceptors can be divided into three types: plasma membrane, young disks membranes, and old disks membranes. High amount of docosahexaenoic acid, abundant illumination, and high respiratory demands make these membranes sensitive to oxidative stress and lipid peroxidation. Human retinas are not easily available for research, therefore most research is done on bovine retinas. However, to follow, in a controlled manner, the changes in membrane properties caused by different factors it seems advisable to apply carefully prepared models of photoreceptor membranes. Using synthetic lipids we prepared liposome models of three types of photoreceptor membranes, and by means of electron paramagnetic resonance spectroscopy and spin labeling technique we compared polarity and fluidity of those model membranes with the properties of membranes consisting of natural lipids extracted from photoreceptor outer segments of bovine retinas. Additionally, we studied the effect of oxidation on the membrane properties in the presence and in the absence of zeaxanthin, which is an antioxidant naturally present in the human retina. The results show that there are significant differences in polarity and fluidity between all investigated membranes, which reflect differences in their lipid composition. The properties of the membranes made of natural photoreceptor outer segment lipids are most similar to the ones of the models of old disks membranes. Oxidation did not change the membrane properties significantly; however, a slight ordering effect was observed in liposomes made of natural photoreceptor outer segment lipids and in the model of old disks membranes. Zeaxanthin affected polarity and fluidity mostly in the model of old disks membranes. The results show that by careful selection and appropriate proportions of lipid mixtures, it is possible to obtain synthetic membranes of the properties similar to the natural ones.
APA, Harvard, Vancouver, ISO, and other styles
6

Naumowicz, Monika. "Electrical Properties of Model Lipid Membranes." Membranes 12, no. 2 (February 21, 2022): 248. http://dx.doi.org/10.3390/membranes12020248.

Full text
Abstract:
Biological membranes are essential components of the living systems, and processes occurring with their participation are related mainly to electric phenomena such as signal transduction, existence of membrane potentials, and transport through the membrane [...]
APA, Harvard, Vancouver, ISO, and other styles
7

Waring, Alan J., Sylvia S. L. Harwig, and Robert L. Lehrer. "Structure and Activity of Protegiun-1 in Model Lipid Membranes." Protein & Peptide Letters 3, no. 3 (June 1996): 177–84. http://dx.doi.org/10.2174/092986650303220615100109.

Full text
Abstract:
Protegrin (PG)-1, an antimicrobial peptide from porcine leukocytes, mediated the release of encapsulated fluorescent dye from vesicles of simulated microbial lipids, suggesting that the peptide interacted strongly with membrane-mimetic ensembles. Circular dichroism measurements of PG-1 in membrane-lipid dispersions and liposomal systems indicated that the peptide assumed a predominantly β-sheet conformation in these environments. Fourier transform infrared measurements of the peptide in microbial lipid films showed that the P­ sheet component was oriented approximately parallel to the surface of the lipid film The ability of PG-1 to associate with and lyse model microbial-lipid membranes is likely to underlie its potent antibiotic properties.
APA, Harvard, Vancouver, ISO, and other styles
8

Kure, Jakob L., Camilla B. Andersen, Thomas E. Rasmussen, B. Christoffer Lagerholm, and Eva C. Arnspang. "Defining the Diffusion in Model Membranes Using Line Fluorescence Recovery after Photobleaching." Membranes 10, no. 12 (December 17, 2020): 434. http://dx.doi.org/10.3390/membranes10120434.

Full text
Abstract:
In this study, we explore the use of line FRAP to detect diffusion in synthetic lipid membranes. The study of the dynamics of these membrane lipids can, however, be challenging. The diffusion in two different synthetic membranes consisting of the lipid mixtures 1:1 DOPC:DPPC and 2:2:1 DOPC:DPPC:Cholesterol was studied with line FRAP. A correlation between diffusion coefficient and temperature was found to be dependent on the morphology of the membrane. We suggest line FRAP as a promising accessible and simple technique to study diffusion in plasma membranes.
APA, Harvard, Vancouver, ISO, and other styles
9

Kahya, Nicoletta. "Light on fluorescent lipids in rafts: a lesson from model membranes." Biochemical Journal 430, no. 3 (August 27, 2010): e7-e9. http://dx.doi.org/10.1042/bj20101196.

Full text
Abstract:
Tracking fluorescent lipids in cellular membranes has been applied for decades to shed light on membrane trafficking, sorting, endocytosis and exocytosis, viral entry, and to understand the functional relevance of membrane heterogeneity, phase separation and lipid rafts. However, fluorescent probes may display different organizing behaviour from their corresponding endogenous lipids. A full characterization of these probes is therefore required for proper interpretation of fluorescence microscopy data in complex membrane systems. Model membrane studies provide essential clues that guide us to design and interpret our experiments, help us to avoid pitfalls and resolve artefacts in complex cellular environments. In the present issue of the Biochemical Journal, Juhasz, Davis and Sharom demonstrate the importance of testing lipid probes systematically in heterogeneous model membranes of specific composition and well-defined thermodynamic properties. The phase-partitioning behaviour of fluorescent probes, alone and/or in combination, cannot simply be assumed, but has to be fully characterized.
APA, Harvard, Vancouver, ISO, and other styles
10

Walczewska, Anna, Barbara Dziedzic, Dawid Stulczewski, and Emilia Zgórzyńska. "Cell membranes. Molecular lipid therapy." Postępy Higieny i Medycyny Doświadczalnej 71 (December 31, 2017): 1239–50. http://dx.doi.org/10.5604/01.3001.0010.7749.

Full text
Abstract:
Membrane lipids, due to diverse molecular structures, electric charge and different functional characteristic, have a profound role in multiple cytophysiological processes. A better understanding of the membrane structure and changes of its function in a wide range of diseases gave rise to a new approach termed membrane lipid therapy and directed to modifying the membranes. The strategies directed to membrane involve a direct regulation of membrane lipid composition that causes a change of the transmembrane protein function and modifies the organization of membrane microdomains, or regulation of enzyme activity and gene expression to alter membrane lipid composition. Membrane therapy assumes the use of new molecules specifically designed to modify lipid composition and function of abnormal signaling proteins. Therefore, modifications of the lipid composition and organization of membrane microdomains become pharmacological targets to reverse pathological changes in the profile of enzymatically and non-enzymatically generated lipid derivatives or to modify signaling pathways in the cell. The present monography is an update of the canonical membrane model by Singer-Nicolson and describes the therapeutic targets related to the regulation of the composition and organization of the lipids in the plasma membrane.
APA, Harvard, Vancouver, ISO, and other styles
More sources

Dissertations / Theses on the topic "Model lipid membrane"

1

Oldham, Alexis Jean. "Modulation of lipid domain formation in mixed model systems by proteins and peptides." View electronic thesis, 2008. http://dl.uncw.edu/etd/2008-1/r1/oldhama/alexisoldham.pdf.

Full text
APA, Harvard, Vancouver, ISO, and other styles
2

Botelho, Ana Vitoria. "Lipid-protein interactions: Photoreceptor membrane model." Diss., The University of Arizona, 2005. http://hdl.handle.net/10150/280765.

Full text
Abstract:
G-protein coupled receptors (GPCRs) are transmembrane proteins capable of recognizing an astonishing variety of biological signals, ranging from photons of light to hormones, odorants, and neurotransmitters involved in key biological signaling processes. The aim of this work is to identify how lipid-protein interactions involving the membrane bilayer ultimately affect such vital biological functions. Here the relationship between the bilayer thickness, hydrophobic mismatch, and protein aggregation are investigated by expanding the framework of membrane-receptor interactions in terms of a new flexible surface model. Previously, we have shown how coupling of the elastic stress-strain due to mismatch of the spontaneous curvature and hydrophobic thickness at the lipid/protein interface can govern the conformational transitions of membrane proteins. This approach has now been extended to include coupling of the lateral organization of the GPCR rhodopsin to the curvature and area stress and strain of the proteolipid membrane. Rhodopsin was labeled with site-specific fluorophores, and a FRET technique was employed to probe protein association in different lipid environments. Moreover, UV-visible spectroscopy was used for thermodynamic characterization of the conformational change of rhodopsin. Lastly, the deformation of the lipids with and without rhodopsin was probed in terms of acyl chain order parameters and relaxation rates by solid-state NMR methods, giving insight into the lipid deformation. The results showed that optimal receptor activation occurs in phosphatidylcholine bilayers of 20-carbon acyl chain length, hence one can say that metarhodopsin II is likely to adopt an elongated shape. Lipids promoting aggregation, or below their gel to liquid crystalline transition temperature all favor formation of metarhodopsin I. The data also showed that association and activation of rhodopsin do not always correlate. In terms of the extended flexible surface model, the stress due to hydrophobic mismatch is coupled via the effective number of lipids surrounding the protein due to the lateral organization of the membrane. The measured changes in rhodopsin-rhodopsin interactions and membrane influences on the conformation of the protein after photoisomerization may be crucial to understanding physiological regulation of the rod disk membranes. They are relevant to understanding the complexity of biomembranes involved in many cellular mechanisms, including signal transduction.
APA, Harvard, Vancouver, ISO, and other styles
3

Polozov, Ivan V. "Interactions of class A and class L amphipathic helical peptides with model membranes." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape16/PQDD_0006/NQ30110.pdf.

Full text
APA, Harvard, Vancouver, ISO, and other styles
4

Bechtella, Leïla. "Molecular analysis of the interactions of the cell-penetrating peptide Penetratin and lipid membranes. Contributions of the lipid PIP2, biophysical approaches and benzophenone photoreactivity in model membranes." Thesis, Sorbonne université, 2019. http://www.theses.fr/2019SORUS045.

Full text
Abstract:
Les peptides vecteurs (CPP) peuvent entrer dans les cellules et y transporter des molécules biologiquement actives. De précédents travaux ont montré que les CPP pouvaient remodeler le cytosquelette d'actine, interagissaient fortement avec les lipides chargés négativement et que le PIP2 pourrait jouer un rôle dans l'internalisation de la Pénétratine. Nos expériences en DSC ont montré que la Pénétratine interagit avec les têtes polaires et influence la fluidité de la membrane de vésicules contenant du PIP2. La présence de PIP2 favorise l’interaction Pénétratine-lipide. De plus, l’estimation de l'affinité de liaison par fluorescence du tryptophane a montré que la Pénétratine a une affinité plus élevée pour le PIP2 que pour la PS. Le photomarquage par affinité couplé à la spectrométrie de masse, à l'aide de peptides fonctionnalisés par une benzophénone (Bzp), a permis d’étudier les interactions non covalentes des CPP et des membranes lipidiques à un niveau moléculaire. Le PIP2 s'est avéré être un partenaire d'interaction de la Pénétratine et a été marqué préférentiellement dans les liposomes contenant du PC, de la PS et du PIP2. Nous avons mis en évidence des réactions secondaires très informatives qui peuvent se produire simultanément lors de l'irradiation UV, dans un unique système biologique : un CPP inséré dans une bicouche lipidique. Ce travail montre comment exploiter de manière originale les différentes réactivités de la Bzp dans le contexte d'une membrane lipidique, informant sur l'interaction CPP/lipide au niveau moléculaire comme la profondeur d'insertion ou la fluidité membranaire au voisinage du CPP
Cell-penetrating peptides (CPP) can cross cell membranes and deliver biologically active molecules into cells. Previous work showed that CPPs could remodel the actin cytoskeleton, interacted strongly with negatively charged lipids and PIP2 could play a role in Penetratin internalization. Our DSC experiments showed that Penetratin interacts with polar head groups and impacts the lipid bilayer fluidity of PIP2-containing liposomes. It indicated that presence of PIP2 in liposomes triggers Penetratin-lipid interaction. Moreover, Penetratin binding affinity for PIP2-containing lipid vesicles, estimated by tryptophan fluorescence, pointed out that Penetratin has a higher affinity for PIP2 than for PS. Affinity photocrosslinking coupled to mass spectrometry, using benzophenone (Bzp)-functionalized peptides, was used to study the non-covalent interactions of CPPs and lipid membranes at a molecular level. PIP2 was found to be a good interaction partner for Penetratin and was preferably labelled in liposomes containing PC, PS and PIP2. We revealed highly informative secondary reactions occurring during UV irradiation that can occur concomitantly in a single biological system: a membrane-active peptide inserted within a phospholipid bilayer. This work shows how to exploit in an original way the different reactivities of Bzp in the context of a lipid membrane, giving access to information on the CPP/lipid interaction at a molecular level such as depth of insertion or membrane fluidity in the CPP vicinity
APA, Harvard, Vancouver, ISO, and other styles
5

Chen, Tianhong, and Bjoern Reinhard. "A novel free standing lipid membrane model designed for dark field microscopy." Diffusion fundamentals 16 (2011) 32, S. 1-3, 2011. https://ul.qucosa.de/id/qucosa%3A13765.

Full text
APA, Harvard, Vancouver, ISO, and other styles
6

Chen, Tianhong, and Bjoern Reinhard. "A novel free standing lipid membrane model designed for dark field microscopy." Universitätsbibliothek Leipzig, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-184882.

Full text
APA, Harvard, Vancouver, ISO, and other styles
7

Walter, Vivien. "Lipid membrane interaction with self-assembling cell-penetrating peptides." Thesis, Strasbourg, 2017. http://www.theses.fr/2017STRAE032/document.

Full text
Abstract:
Les peptides pénétrateurs de cellule (CPP) sont des oligopeptides cationiques faisant parti des vecteurs les plus étudiés dans le cadre du développement du transport ciblé de médicament à l’intérieur de l’organisme. Les applications principales sont par exemple le traitement des cancers ou la thérapie génique. Néanmoins, certaines caractéristiques des CPPs rendent leur utilisation médicale compliquée, tels que leur manque de spécificité à l’égard des cellules cibles ou la perte de leurs propriétés pénétrantes lorsqu’un cargo moléculaire leur est greffé. L’une des solutions envisagées pour résoudre ces problèmes est le greffage sur des polypeptides di-blocs auto-assemblés basés sur de l’élastine (ELPBC), des systèmes développés par l’équipe d’Ashutosh Chilkoti à l’Université de Duke (USA). Des travaux précédents ont montré que ces macromolécules, que l’on appelle CPP-ELPBC, retrouvaient les propriétés pénétrantes du CPP même en présence d’un cargo et permettaient également d’induire une spécificité à l’encontre des cellules cancéreuses. En revanche, le mécanisme de pénétration de ces systèmes restait inconnu.Dans cette thèse, je me suis concentré sur l’étude du mécanisme de pénétration des CPP et des CPP-ELPBC au travers de membranes lipidiques modèles, et en particulier sur l’adsorption de ces molécules à la surface de vésicules unilamellaires géantes (GUV). Le développement d’une nouvelle méthode de quantification de la fluorescence en microscopie confocale m’a permis de réaliser des mesures simples de comptage de peptides à la surface des vésicules, ce qui m’a permis par la suite de procéder à des mesures thermodynamiques de l’adsorption des peptides
Cell-penetrating peptides (CPP) are cationic oligopeptides currently investigated as potential vectors for targeted drug delivery design, for applications in cancer treatment and/or gene therapy. Nevertheless, some drawbacks make the CPP complex for medical applications, such as their lack of specificity toward target cells or the loss of their penetrating properties once they have been grafted with a molecular cargo. One of the solutions studied to overcome these issues is the binding of the CPP unit on a self-assembling elastin-like diblock polypeptide (ELPBC), a macromolecular system designed by the team of Ashutosh Chilkoti from Duke University (USA). While it has already been proven that these molecules, named CPP-ELPBC, recover the penetrating properties of the CPP despite the presence of a cargo and also induce a selectivity toward tumorous cells, the exact mechanism of translocation is still under debate.In this PhD thesis, I focused on the investigation of the translocation mechanism of the CPP and CPP-ELPBC using model lipid membranes, and specifically the adsorption of these molecules at the surface of giant unilamellar vesicles (GUV). The development of a new quantification method of fluorescence in confocal microscopy allowed me to directly count the peptides adsorbed on the surface of the GUVs, which I used to perform thermodynamic measurements on the peptide adsorption
APA, Harvard, Vancouver, ISO, and other styles
8

Alaimo, Cristina. "Bacterial N-glycosilation: a model to study lipid-linked oligosaccharide translocation across the membrane /." Zürich : ETH, 2006. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=16728.

Full text
APA, Harvard, Vancouver, ISO, and other styles
9

Baumgart, Tobias. "Herstellung und physikochemische Charakterisierung von planaren gestützten Lipid-Modellmembran-Systemen Preparation and physicochemical characterisation of planar supported lipid model membrane systems /." [S.l.] : [s.n.], 2001. http://ArchiMeD.uni-mainz.de/pub/2001/0123/diss.pdf.

Full text
APA, Harvard, Vancouver, ISO, and other styles
10

Higson, Seamus P. J. "Charge transfer reactions of some naturally occuring quinones across a novel biomimetic lipid model membrane." Thesis, University of Southampton, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.316187.

Full text
APA, Harvard, Vancouver, ISO, and other styles
More sources

Books on the topic "Model lipid membrane"

1

Les modèles moléculaires de biomembranes. Paris: Hermann, 1987.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
2

L, Longo Marjorie, Risbud Subhash H, Jue Thomas, and SpringerLink (Online service), eds. Biomembrane Frontiers: Nanostructures, Models, and the Design of Life. Totowa, NJ: Humana Press, 2009.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
3

Derek, Marsh, ed. Phospholipid bilayers: Physical principles and models. New York: Wiley, 1987.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
4

Brown, Robert Stephen. Fluorescence measurements in surface stabilized membranes as a model for a lipid membrane-based fibre-optic chemical sensor. 1988.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
5

Wahid, Mohamed Sameer Al-Abdul. Oxygen as a paramagnetic probe for nuclear magnetic resonance: Structure and paramagnetic profile of a lipid bilayer/membrane model system. 2005.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
6

Cholesterol in membrane models. Boca Raton, Fla: CRC Press, 1992.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
7

Electrical Properties of Model Lipid Membranes. MDPI, 2022. http://dx.doi.org/10.3390/books978-3-0365-4057-3.

Full text
APA, Harvard, Vancouver, ISO, and other styles
8

Naumowicz, Monika. Electrical Properties of Model Lipid Membranes. Mdpi AG, 2022.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
9

Katsaras, John, Georg Pabst, Norbert Kucerka, and Mu-Ping Nieh. Liposomes, Lipid Bilayers and Model Membranes: From Basic Research to Application. Taylor & Francis Group, 2014.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
10

Liposomes, Lipid Bilayers and Model Membranes: From Basic Research to Application. Taylor & Francis Group, 2014.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
More sources

Book chapters on the topic "Model lipid membrane"

1

Verkleij, A. J., R. Van Venetië, J. Leunissen-Bijvelt, B. de Kruijff, M. Hope, and P. R. Cullis. "Membrane Fusion and Lipid Polymorphism." In Physical Methods on Biological Membranes and Their Model Systems, 179–92. Boston, MA: Springer US, 1985. http://dx.doi.org/10.1007/978-1-4684-7538-8_13.

Full text
APA, Harvard, Vancouver, ISO, and other styles
2

Kimelberg, H. K. "Membrane Fluidity and Lipid Composition." In Physical Methods on Biological Membranes and Their Model Systems, 261–76. Boston, MA: Springer US, 1985. http://dx.doi.org/10.1007/978-1-4684-7538-8_19.

Full text
APA, Harvard, Vancouver, ISO, and other styles
3

Prosser, R. Scott, and Charles R. Sanders. "Solid State NMR Approaches to the Study of Membrane Proteins in Magnetically Aligned Model Membranes." In Lipid Bilayers, 207–31. Berlin, Heidelberg: Springer Berlin Heidelberg, 2001. http://dx.doi.org/10.1007/978-3-662-04496-4_10.

Full text
APA, Harvard, Vancouver, ISO, and other styles
4

Keough, K. M. W., J. Pérez-Gil, G. Simatos, J. Tucker, K. Nag, C. Boland, J. Stewart, et al. "Hydrophobic Pulmonary Surfactant Proteins in Model Lipid Systems." In Progress in Membrane Biotechnology, 241–52. Basel: Birkhäuser Basel, 1991. http://dx.doi.org/10.1007/978-3-0348-7454-0_17.

Full text
APA, Harvard, Vancouver, ISO, and other styles
5

Tilcock, C., S. Eastman, and D. Fisher. "Determination of Lipid Asymmetry and Exchange in Model Membrane Systems." In Cell and Model Membrane Interactions, 1–14. Boston, MA: Springer US, 1991. http://dx.doi.org/10.1007/978-1-4615-3854-7_1.

Full text
APA, Harvard, Vancouver, ISO, and other styles
6

McIntosh, Thomas J., Alan D. Magid, and Sidney A. Simon. "Short-Range Repulsive Interactions between the Surfaces of Lipid Membranes." In Cell and Model Membrane Interactions, 249–65. Boston, MA: Springer US, 1991. http://dx.doi.org/10.1007/978-1-4615-3854-7_15.

Full text
APA, Harvard, Vancouver, ISO, and other styles
7

Grainger, D. W., K. M. Maloney, X. Huang, M. Ahlers, A. Reichert, H. Ringsdorf, C. Salesse, J. N. Herron, V. Hlady, and K. Lim. "Binding, Interaction, and Organization of Proteins with Lipid Model Membranes." In Progress in Membrane Biotechnology, 64–82. Basel: Birkhäuser Basel, 1991. http://dx.doi.org/10.1007/978-3-0348-7454-0_6.

Full text
APA, Harvard, Vancouver, ISO, and other styles
8

Lewis, Ruthven N. A. H., David A. Mannock, and Ronald N. McElhaney. "Differential Scanning Calorimetry in the Study of Lipid Phase Transitions in Model and Biological Membranes." In Methods in Membrane Lipids, 171–95. Totowa, NJ: Humana Press, 2007. http://dx.doi.org/10.1007/978-1-59745-519-0_12.

Full text
APA, Harvard, Vancouver, ISO, and other styles
9

Cruzeiro, Leonor, and Kelo M. C. Da Silva. "Quantum Mechanical Model for Passive Transport through Bilayer Lipid Membranes." In Recent Advances in Biological Membrane Studies, 165–78. Boston, MA: Springer US, 1985. http://dx.doi.org/10.1007/978-1-4684-4979-2_12.

Full text
APA, Harvard, Vancouver, ISO, and other styles
10

Lewis, Ruthven N. A. H., and Ronald N. McElhaney. "Fourier Transform Infrared Spectroscopy in the Study of Lipid Phase Transitions in Model and Biological Membranes." In Methods in Membrane Lipids, 207–26. Totowa, NJ: Humana Press, 2007. http://dx.doi.org/10.1007/978-1-59745-519-0_14.

Full text
APA, Harvard, Vancouver, ISO, and other styles

Conference papers on the topic "Model lipid membrane"

1

Lykotrafitis, George, and He Li. "Two-Component Coarse-Grain Model for Erythrocyte Membrane." In ASME 2011 International Mechanical Engineering Congress and Exposition. ASMEDC, 2011. http://dx.doi.org/10.1115/imece2011-62133.

Full text
Abstract:
Biological membranes are vital components of living cells as they function to maintain the structural integrity of the cells. Red blood cell (RBC) membrane comprises the lipid bilayer and the cytoskeleton network. The lipid bilayer consists of phospholipids, integral membrane proteins, peripheral proteins and cholesterol. It behaves as a 2D fluid. The cytoskeleton is a network of spectrin tetramers linked at the actin junctions. It is connected to the lipid bilayer primarily via Band-3 and ankyrin proteins. In this paper, we introduce a coarse-grained model with high computational efficiency for simulating a variety of dynamic and topological problems involving erythrocyte membranes. Coarse-grained agents are used to represent a cluster of lipid molecules and proteins with a diameter on the order of lipid bilayer thickness and carry both translational and rotational freedom. The membrane cytoskeleton is modeled as a canonical exagonal network of entropic springs that behave as Worm-Like-Chains (WLC). By simultaneously invoking these characteristics, the proposed model facilitates simulations that span large length-scales (∼ μm) and time-scales (∼ ms). The behavior of the model under shearing at different rates is studied. At low strain rates, the resulted shear stress is mainly due to the spectrin network and it shows the characteristic non-linear behavior of entropic networks, while the viscosity of the fluid-like lipid bilayer contributes to the resulting shear stress at higher strain rates. The apparent ease of this model in combining the spectrin network with the lipid bilayer presents a major advantage over conventional continuum methods such as finite element or finite difference methods for cell membranes.
APA, Harvard, Vancouver, ISO, and other styles
2

Zhu, Qiang, Zhangli Peng, and Robert J. Asaro. "Investigation of RBC Remodeling With a Multiscale Model." In ASME 2010 First Global Congress on NanoEngineering for Medicine and Biology. ASMEDC, 2010. http://dx.doi.org/10.1115/nemb2010-13121.

Full text
Abstract:
Erythrocyte (red blood cell, or RBC) possesses one of the simplest and best characterized molecular architectures among all cells. It contains cytosol enclosed inside a composite membrane consisting of a fluidic lipid bilayer reinforced by a single layer of protein skeleton pinned to it. In its normal state, this system demonstrates tremendous structural stability, manifested in its ability to sustain large dynamic deformations during circulation. On the other hand, it has been illustrated in experiments that triggered by mechanical loads structural remodeling may occur. A canonical example of this remodeling is vesiculation, referring to the partial separation of the lipid bilayer from the protein skeleton and the formation of vesicles that contain lipids only.
APA, Harvard, Vancouver, ISO, and other styles
3

Muddana, Hari S., Ramachandra R. Gullapalli, and Peter J. Butler. "Tension Induces Changes in Lipid Lateral Diffusion in Model Fluid-Phase Membranes." In ASME 2009 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2009. http://dx.doi.org/10.1115/sbc2009-206867.

Full text
Abstract:
Shear stress due to blood flow on endothelial cells elicits numerous responses including G-protein coupled receptor activation and integrin-mediated signaling. Shear-induced change in membrane fluidity has been suggested to be one of the earliest mechanosensing mechanism involved in these processes [1, 2]. Alternatively, it has been suggested that shear forces are transduced through glycocalyx directly to transmembrane proteins and cytoskeleton [3], with very little shear force sensed by the membrane. It is not yet clear whether physiological tensions can alter membrane fluidity significantly.
APA, Harvard, Vancouver, ISO, and other styles
4

Nguyen, Mary-Anne, and Stephen A. Sarles. "Microfluidic Generation, Encapsulation and Characterization of Asymmetric Droplet Interface Bilayers." In ASME 2016 Conference on Smart Materials, Adaptive Structures and Intelligent Systems. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/smasis2016-9034.

Full text
Abstract:
Our research focuses on creating smart materials that utilize synthetic cell membranes assembled at liquid interfaces for autonomic sensing, actuation, and energy conversion. Unlike single membrane assemblies, systems featuring many membranes have the potential to offer multi-functionality, greater transduction sensitivity, and even emergent behaviors in response to environmental stimuli, similar to living tissue, which utilizes networks of highly packed cells to accomplish tasks. Here, we present for the first time a novel microfluidic platform capable of generating a stream of alternating droplet compositions, i.e. A-B-A-B, and sequentially capturing these droplets in precise locations to enable the spontaneous formation of synthetic lipid bilayers between droplets of different compositions (i.e. A and B) in an enclosed substrate. This platform preserves a key feature of the droplet interface bilayer (DIB) method, which allows asymmetric conditions within and across the membrane to be prescribed by simply using droplets containing different species. In this work, we demonstrate the ability to assemble bilayers consisting of asymmetric lipid compositions and, separately, show that alternating droplets containing the same lipid type can also be used to control the direction of ion channel insertion. In the first study, A and B droplet types contain liposomes comprised of different lipid types, which are used to establish an asymmetric composition of the leaflets that make up the lipid bilayer. This asymmetry results in a dc, non-zero membrane potential, which we measure via membrane capacitance versus bias voltage. In the second study, alamethicin peptides are included in only one of the droplet types, which enable voltage-dependent insertion to occur only at one polarity. Cyclic voltammetry measurements are performed to confirm the direction of insertion of alamethicin channels in bilayers. Also, these results show the ability to perform simultaneously electrical measurements on multiple DIB, which increases the experimental capacity and efficiency of a microfluidic approach. The ability to produce alternating droplets in a high throughput manner with electrical access provides a system to investigate the effects of lipid asymmetry on the function of membrane proteins in a controlled model system.
APA, Harvard, Vancouver, ISO, and other styles
5

Li, He, and George Lykotrafitis. "Modeling Diffusion and Vesiculation in Defective Human Erythrocyte Membrane." In ASME 2013 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/sbc2013-14203.

Full text
Abstract:
The hemolytic disorders of hereditary spherocytosis (HS) and hereditary elliptocytosis (HE) affect the lives of millions of individuals worldwide. In HS and HE, connections in the vertical and horizontal directions between components of the RBC membrane (see Fig. 1(a)), are disrupted due to defective proteins, leading to loss of the structural and functional integrity of the membrane (1–2). Moreover, disruptions of either the vertical interactions or horizontal interactions affect the lateral diffusivity of the mobile band 3 proteins, as the motion of band 3 in the RBC membrane is confined by the cytoskeleton (3). Although a number of coarse-grained molecular dynamics (CGMD) RBC membrane models have been developed in the past two decades, very few RBC membrane models have been used to study the disordered band 3 diffusion and membrane vesiculation in HS and HE. The implicit representations of either the lipid bilayer or the cytoskeleton in these membrane models limit their applications in the membrane instability problems in HS and HE. In this extended abstract, we develop a two-component CGMD human RBC membrane model that explicitly comprises both the lipid bilayer and the cytoskeleton. In this way, the interactions between the cytoskeleton and the proteins embedded in the lipid bilayer can be simulated. The proposed model allows us to measure the band 3 lateral mobility and simulate the process of membrane vesiculation in the membrane with protein defects.
APA, Harvard, Vancouver, ISO, and other styles
6

El-Beyrouthy, Joyce, and Eric C. Freeman. "Rapid and Real-Time Measurement of Membrane Potential Through Intramembrane Field Compensation." In ASME 2020 Conference on Smart Materials, Adaptive Structures and Intelligent Systems. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/smasis2020-2352.

Full text
Abstract:
Abstract Synthetic lipid membranes are self-assembled biomolecular double layers designed to approximate the properties of living cell membranes. These membranes are employed as model systems for studying the interactions of cellular envelopes with the surrounding environment in a controlled platform. They are constructed by dispersing amphiphilic lipids into a combination of immiscible fluids enabling the biomolecules to self-assemble into ordered sheets, or monolayers at the oil-water interface. The adhesion of two opposing monolayer sheets forms the membrane, or the double layer. The mechanical properties of these synthetic membranes often differ from biological ones mainly due to the presence of residual solvent in between the leaflets. In fact, the double layer compresses in response to externally applied electrical field with an intensity that varies depending on the solvent present. While typically viewed as a drawback associated with their assembly, in this work the elasticity of the double layer is utilized to further quantify complex biophysical phenomena. The adsorption of charged molecules on the surface of a lipid bilayer is a key property to decipher biomolecule interactions at the interface of the cell membrane, as well as to develop effective antimicrobial peptides and similar membrane-active molecules. This adsorption generates a difference in the boundary potentials on either side of the membrane which may be tracked through electrophysiology. The soft synthetic membranes produced in the laboratory compress when exposed to an electric field. Tracking the minimum membrane capacitance allows for quantifying when the intrinsic electric field produced by the asymmetry is properly compensated by the supplied transmembrane voltage. The technique adopted in this work is the intramembrane field compensation (IFC). This technique focuses on the current generated by the bilayer in response to a sinusoidal voltage with a DC component, VDC. Briefly, the output sinusoidal current is divided into its harmonics and the second harmonic equals zero when VDC compensates the internal electric field. In this work, we apply the IFC technique to droplet interface bilayers (DIB) enabling the development of a biological sensor. A certain membrane elasticity is needed for accurate measurements and is tuned through the solvent selection. The asymmetric DIBs are formed, and an automated PID-controlled IFC design is implemented to rapidly track and compensate the membrane asymmetry. The closed loop system continuously reads the current and generates the corresponding voltage until the second harmonic is abated. This research describes the development and optimization of a biological sensor and examines how varying the structure of the synthetic membrane influences its capabilities for detecting membrane-environment interactions. This platform may be applied towards studying the interactions of membrane-active molecules and developing models for the associated phenomena to enhance their design.
APA, Harvard, Vancouver, ISO, and other styles
7

Alapati, Raghava, Dorel Moldovan, and Ram V. Devireddy. "Asymmetry of Structural Characteristics of Lipid Bilayers Induced by Dimethylsulfoxide: An Atomistic Simulation Study." In ASME 2008 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2008. http://dx.doi.org/10.1115/sbc2008-192813.

Full text
Abstract:
In a typical cryopreservation protocol, the system to be preserved is first equilibrated with chemicals known as cryoprotective agents (CPAs). CPAs have been shown to alleviate cell damage from either the solute effects or the formation of intracellular ice during the subsequent freezing process. Thus, an extensive body of literature reporting the effects of CPAs on cellular systems has been accumulated over the last 50 years; detailing largely experimental interactions between cell systems and chemicals. Recent advances in computational methodology now offer an additional dimension in our ability to understand the molecular interactions between cell membranes, idealized as lipid bilayers and CPAs at atomistic scales. Computer simulations provide unique capabilities for analyzing biomembrane properties from atomistic perspective with a degree of detail that is hard to reach by other techniques. The excellent agreement with the experiment obtained in various molecular dynamics (MD) studies [1] on simple model membranes has raised the confidence in applying the molecular dynamics simulations to even more complex systems. Dimethylsulfoxide (DMSO) is one of the most widely used solvents in cell biology and cryopreservation. During a typical cryopreservation protocol the DMSO composition of aqueous buffers inside and outside of the cell is known to differ considerably. To model and understand the structural changes in cell membranes in such a situation we performed MD simulations of an idealized lipid bilayer membrane which separates two aqueous reservoirs with and without DMSO. Zwitterionic dimyritoylphosphatidylcholine (DMPC) lipid bilayers was chosen as the model membrane.
APA, Harvard, Vancouver, ISO, and other styles
8

Bukowski, Michael, Brij Singh, James Roemmich, and Kate Larson. "Lipidomic analysis of TRPC1 Ca2+-permeable channel-knock out mouse demonstrates a vital role in placental tissue sphingolipid and triacylglycerol homeostasis under high-fat diet." In 2022 AOCS Annual Meeting & Expo. American Oil Chemists' Society (AOCS), 2022. http://dx.doi.org/10.21748/tjdt4839.

Full text
Abstract:
Placental function including oxygen delivery and nutrient transport are critical determinants of fetal growth, moderating the risks of obesity and metabolic diseases later in life. Previously, we demonstrated in a mouse model that parental diet and exercise play important roles in placental lipid content and inflammation. Transient receptor potential canonical channel 1 (TRPC1) is a Ca2+-permeable integral membrane protein. We have demonstrated that TRPC1 increases total body adiposity in mice by decreasing the efficacy of exercise to limit adipose accumulation under a high fat (HF) diet. Importantly, intracellular calcium may regulate total body adiposity and increased total body adiposity could promote placental lipid accumulation. Similarly, intracellular calcium regulates membrane lipid content via the activation of the protein kinase C. Membrane lipids such as sphingomyelin are key regulators of cell signaling. Maternal HF diets increase placental tissue lipid concentrations resulting in compromised nutrient transport to fetus. However, the specific lipid species that accumulate due to the absence of the placental TRPC1 gene under maternal HF diet feeding is not yet known. We hypothesized that placental tissue response to a maternal HF diet is disrupted in TRPC1 mice fed a maternal HF diet resulting in greater cellular sphingomyelin concentrations. Results showed placentae from TRPC1 KO mice fed high fat diet (45% en, HF) had increased sphingomyelin concentrations compared to control diet (16% en, NF). Placentae from WT mice fed HF diet exhibited diet-dependent increases in ceramide concentration with no concomitant increase in sphingomyelins compared to NF fed WT mice. Additionally, 11 placental triacylglycerol (TAG) species were different based on diet, 16 based on genotype, and 5 were affected by both diet and genotype. These results suggest that during a HF diet, loss of TRPC1 function reduces placental sphingomyelin hydrolysis into ceramide and that placental TAG concentrations respond in diet- and genotype-dependent manner.
APA, Harvard, Vancouver, ISO, and other styles
9

Jiang, Yanfei, Guy M. Genin, Srikanth Singamaneni, and Elliot L. Elson. "Interfacial Phases on Giant Unilamellar Vesicles." In ASME 2012 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/sbc2012-80942.

Full text
Abstract:
Lipid nanodomains in cell membranes are believed to play a significant role in a number of critical cellular processes (Elson, et al., 2010). These include, for example, replication processes in enveloped viruses such as bird flu and HIV and signaling mechanisms underlying pathological conditions such as cancer. Due to the potential for developing new disease treatments through the control of these membrane rafts, the biophysics underlying their formation has been the subject of intense study, much of this focused on domain formation in giant unilamellar lipid vesicles (GUVs), a simplified model system.
APA, Harvard, Vancouver, ISO, and other styles
10

Sadik, Mohamed M., David I. Shreiber, Jerry W. Shan, and Hao Lin. "Extreme Elongation of Vesicles Under DC Electric Fields." In ASME 2008 International Mechanical Engineering Congress and Exposition. ASMEDC, 2008. http://dx.doi.org/10.1115/imece2008-68102.

Full text
Abstract:
Electrodeformation refers to the deformation of cell or vesicle lipid membranes under the application of an electric field. Such a phenomenon often accompanies electroporation processes, and also can be leveraged to detect pathological changes in cells. Recent studies have suggested that the electrical conductivity difference across the lipid membrane is a dominant factor in determining the characteristics of deformation, and various regimes of deformation were observed. Using a vesicle model system, the current work is the first report of extreme elongation of vesicles of high conductivity ratio under DC electric fields. The results suggest that the osmolarity difference between the encapsulated and bathing solutions may contribute to such abnormal deformation behavior.
APA, Harvard, Vancouver, ISO, and other styles

Reports on the topic "Model lipid membrane"

1

Kanner, Joseph, Edwin Frankel, Stella Harel, and Bruce German. Grapes, Wines and By-products as Potential Sources of Antioxidants. United States Department of Agriculture, January 1995. http://dx.doi.org/10.32747/1995.7568767.bard.

Full text
Abstract:
Several grape varieties and red wines were found to contain large concentration of phenolic compounds which work as antioxidant in-vitro and in-vivo. Wastes from wine production contain antioxidants in large amounts, between 2-6% on dry material basis. Red wines but also white wines were found to prevent lipid peroxidation of turkey muscle tissues stored at 5oC. The antioxidant reaction of flavonoids found in red wines against lipid peroxidation were found to depend on the structure of the molecule. Red wine flavonoids containing an orthodihydroxy structure around the B ring were found highly active against LDL and membrane lipid peroxidation. The antioxidant activity of red wine polyphenols were also found to be dependent on the catalyzer used. In the presence of H2O2-activated myoglobin, the inhibition efficiency was malvidin 3-glucoside>catechin>malvidin>resveratol. However, in the presence of an iron redox cycle catalyzer, the order of effectiveness was resveratol>malvidin 3-glucoside = malvidin>catechin. Differences in protein binding were found to affect antioxidant activity in inhibiting LDL oxidation. A model protein such as BSA, was investigated on the antioxidant activity of phenolic compounds, grape extracts, and red wines in a lecithin-liposome model system. Ferulic acid followed by malvidin and rutin were the most efficient in inhibiting both lipid and protein oxidation. Catechin, a flavonal found in red-wines in relatively high concentration was found to inhibit myoglobin catalyzed linoleate membrane lipid peroxidation at a relatively very low concentration. This effect was studied by the determination of the by-products generated from linoleate during oxidation. The study showed that hydroperoxides are catalytically broken down, not to an alcohol but most probably to a non-radical adduct. The ability of wine-phenolics to reduce iron and from complexes with metals were also demonstrated. Low concentration of wine phenolics were found to inhibit lipoxygenase type II activity. An attempt to understand the bioavailability in humans of antocyanins from red wine showed that two antocyanins from red wine were found unchanged in human urine. Other antocyanins seems to undergo molecular modification. In hypercholesterolemic hamsters, aortic lipid deposition was significantly less in animals fed diets supplemented with either catechin or vitamin E. The rate of LDL accumulation in the carotid arteries was also significantly lower in the catechin and vitamin E animal groups. These results suggested a novel mechanism by which wine phenolics are associated with decreased risk of coronary heart diseases. This study proves in part our hypothesis that the "French Paradox" could be explained by the action of the antioxidant effects of phenolic compounds found at high concentration in red wines. The results of this study argue that it is in the interest of public health to increase the consumption of dietary plant falvonoids. Our results and these from others, show that the consumption of red wine or plant derived polyphenolics can change the antioxidant tone of animal and human plasma and its isolated components towards oxidative reactions. However, we need more research to better understand bioavailability and the mechanism of how polyphenolics affect health and disease.
APA, Harvard, Vancouver, ISO, and other styles
2

Epel, Bernard, and Roger Beachy. Mechanisms of intra- and intercellular targeting and movement of tobacco mosaic virus. United States Department of Agriculture, November 2005. http://dx.doi.org/10.32747/2005.7695874.bard.

Full text
Abstract:
To cause disease, plant viruses must replicate and spread locally and systemically within the host. Cell-to-cell virus spread is mediated by virus-encoded movement proteins (MPs), which modify the structure and function of plasmodesmata (Pd), trans-wall co-axial membranous tunnels that interconnect the cytoplasm of neighboring cells. Tobacco mosaic virus (TMV) employ a single MP for cell- cell spread and for which CP is not required. The PIs, Beachy (USA) and Epel (Israel) and co-workers, developed new tools and approaches for study of the mechanism of spread of TMV that lead to a partial identification and molecular characterization of the cellular machinery involved in the trafficking process. Original research objectives: Based on our data and those of others, we proposed a working model of plant viral spread. Our model stated that MPᵀᴹⱽ, an integral ER membrane protein with its C-terminus exposed to the cytoplasm (Reichel and Beachy, 1998), alters the Pd SEL, causes the Pd cytoplasmic annulus to dilate (Wolf et al., 1989), allowing ER to glide through Pd and that this gliding is cytoskeleton mediated. The model claimed that in absence of MP, the ER in Pd (the desmotubule) is stationary, i.e. does not move through the Pd. Based on this model we designed a series of experiments to test the following questions: -Does MP potentiate ER movement through the Pd? - In the presence of MP, is there communication between adjacent cells via ER lumen? -Does MP potentiate the movement of cytoskeletal elements cell to cell? -Is MP required for cell-to-cell movement of ER membranes between cells in sink tissue? -Is the binding in situ of MP to RNA specific to vRNA sequences or is it nonspecific as measured in vitro? And if specific: -What sequences of RNA are involved in binding to MP? And finally, what host proteins are associated with MP during intracellular targeting to various subcellular targets and what if any post-translational modifications occur to MP, other than phosphorylation (Kawakami et al., 1999)? Major conclusions, solutions and achievements. A new quantitative tool was developed to measure the "coefficient of conductivity" of Pd to cytoplasmic soluble proteins. Employing this tool, we measured changes in Pd conductivity in epidermal cells of sink and source leaves of wild-type and transgenic Nicotiana benthamiana (N. benthamiana) plants expressing MPᵀᴹⱽ incubated both in dark and light and at 16 and 25 ᵒC (Liarzi and Epel, 2005 (appendix 1). To test our model we measured the effect of the presence of MP on cell-to-cell spread of a cytoplasmic fluorescent probe, of two ER intrinsic membrane protein-probes and two ER lumen protein-probes fused to GFP. The effect of a mutant virus that is incapable of cell-to-cell spread on the spread of these probes was also determined. Our data shows that MP reduces SEL for cytoplasmic molecules, dilates the desmotubule allowing cell-cell diffusion of proteins via the desmotubule lumen and reduces the rate of spread of the ER membrane probes. Replicase was shown to enhance cell-cell spread. The data are not in support of the proposed model and have led us to propose a new model for virus cell-cell spread: this model proposes that MP, an integral ER membrane protein, forms a MP:vRNAER complex and that this ER-membrane complex diffuses in the lipid milieu of the ER into the desmotubule (the ER within the Pd), and spreads cell to cell by simple diffusion in the ER/desmotubule membrane; the driving force for spread is the chemical potential gradient between an infected cell and contingent non-infected neighbors. Our data also suggests that the virus replicase has a function in altering the Pd conductivity. Transgenic plant lines that express the MP gene of the Cg tobamovirus fused to YFP under the control the ecdysone receptor and methoxyfenocide ligand were generated by the Beachy group and the expression pattern and the timing and targeting patterns were determined. A vector expressing this MPs was also developed for use by the Epel lab . The transgenic lines are being used to identify and isolate host genes that are required for cell-to-cell movement of TMV/tobamoviruses. This line is now being grown and to be employed in proteomic studies which will commence November 2005. T-DNA insertion mutagenesis is being developed to identify and isolate host genes required for cell-to-cell movement of TMV.
APA, Harvard, Vancouver, ISO, and other styles
3

O'Neill, Sharman, Abraham Halevy, and Amihud Borochov. Molecular Genetic Analysis of Pollination-Induced Senescence in Phalaenopsis Orchids. United States Department of Agriculture, 1991. http://dx.doi.org/10.32747/1991.7612837.bard.

Full text
Abstract:
The project investigated the molecular genetic and biochemical basis of pollination-induced senescence of Phalaenopsis flowers. This experimental system offered unique advantages in that senescence is strictly regulated by pollination, providing the basis to experimentally initiate and synchronize senescence in populations of flowers. The postpollination syndrome in the Phalaenopsis orchid system was dissected by investigating the temporal and spatial regulation of ACC synthase gene expression. In the stigma, pollen-borne auxin induces the expression of the auxin-regulated ACC synthase (PS-ACS2) gene, resulting in ACC synthesis within 1 h following pollination. Newly formed ACC is oxidized by basal constitutive ACC oxidase to ethylene, which then induces the expression of the ethylene-regulated ACC synthase(PS-ACS1) and oxidase (ACO1) genes for further autocatalytic production of ethylene. It is speculated that during the 6-h period following pollination, emasculation leads to the production or release of a sensitivity factor that sensitizes the cells of the stigma to ethylene. ACC and ethylene molecules are translocated from the stigma to the labellum and perianth where ethylene induces the expression of PS-ACS1 and ACO1 resulting in an increased production of ACC and ethylene. Organ-localized ethylene is responsible for inrolling and senescence of the labellum and perianth. The regulation of ethylene sensitivity and signal transduction events in pollinated flowers was also investigated. The increase in ethylene sensitivity appeared in both the flower column and the perianth, and was detected as early as 4 h after pollination. The increase in ethylene sensitivity following pollination was not dependent on endogenous ethylene production. Application of linoleic and linoleic acids to Phalaenopsis and Dendrobium flowers enhanced their senescence and promoted ethylene production. Several major lipoxygenase pathway products including JA-ME, traumatic acid, trans-2-hexenal and cis-3-hexenol, also enhanced flower senescence. However, lipoxygenase appears to not be directly involved in the endogenous regulation of pollination-induced Phalaenopsis and Dendrobium flower senescence. The data suggest that short-chain saturated fatty acids may be the ethylene "sensitivity factors" produced following pollination, and that their mode of action involves a decrease in the order of specific regions i the membrane lipid bilayer, consequently altering ethylene action. Examination of potential signal transduction intermediates indicate a direct involvement of GTP-binding proteins, calcium ions and protein phosphorylation in the cellular signal transduction response to ethylene following pollination. Modulations of cytosolic calcium levels allowed us to modify the flowers responsiveness to ethylene.
APA, Harvard, Vancouver, ISO, and other styles
4

Fallik, Elazar, Robert Joly, Ilan Paran, and Matthew A. Jenks. Study of the Physiological, Molecular and Genetic Factors Associated with Postharvest Water Loss in Pepper Fruit. United States Department of Agriculture, December 2012. http://dx.doi.org/10.32747/2012.7593392.bard.

Full text
Abstract:
The fruit of pepper (Capsicum annuum) commonly wilts (or shrivels) during postharvest storage due to rapid water loss, a condition that greatly reduces its shelf life and market value. The fact that pepper fruit are hollow, and thus have limited water content, only exacerbates this problem in pepper. The collaborators on this project completed research whose findings provided new insight into the genetic, physiological, and biochemical basis for water loss from the fruits of pepper (Capsicum annuum and related Capsicum species). Well-defined genetic populations of pepper were used in this study, the first being a series of backcross F₁ and segregating F₂, F₃, and F₄ populations derived from two original parents selected for having dramatic differences in fruit water loss rate (very high and very low water loss). The secondly population utilized in these studies was a collection of 50 accessions representing world diversity in both species and cultivar types. We found that an unexpectedly large amount of variation was present in both fruit wax and cutin composition in these collections. In addition, our studies revealed significant correlations between the chemical composition of both the fruit cuticular waxes and cutin monomers with fruit water loss rate. Among the most significant were that high alkane content in fruit waxes conferred low fruit water loss rates and low permeability in fruit cuticles. In contrast, high amounts of terpenoids (plus steroidal compounds) were associated with very high fruit water loss and cuticle permeability. These results are consistent with our models that the simple straight chain alkanes pack closely together in the cuticle membrane and obstruct water diffusion, whereas lipids with more complex 3-dimensional structure (such as terpenoids) do not pack so closely, and thus increase the diffusion pathways. The backcross segregating populations were used to map quantitative trait loci (QTLs) associated with water loss (using DART markers, Diversity Arrays Technology LTD). These studies resulted in identification of two linked QTLs on pepper’s chromosome 10. Although the exact genetic or physiological basis for these QTLs function in water loss is unknown, the genotypic contribution in studies of near-isogenic lines selected from these backcross populations reveals a strong association between certain wax compounds, the free fatty acids and iso-alkanes. There was also a lesser association between the water loss QTLs with both fruit firmness and total soluble sugars. Results of these analyses have revealed especially strong genetic linkages between fruit water loss, cuticle composition, and two QTLs on chromosome 10. These findings lead us to further speculate that genes located at or near these QTLs have a strong influence on cuticle lipids that impact water loss rate (and possibly, whether directly or indirectly, other traits like fruit firmness and sugar content). The QTL markers identified in these studies will be valuable in the breeding programs of scientists seeking to select for low water loss, long lasting fruits, of pepper, and likely the fruits of related commodities. Further work with these newly developed genetic resources should ultimately lead to the discovery of the genes controlling these fruit characteristics, allowing for the use of transgenic breeding approaches toward the improvement of fruit postharvest shelf life.
APA, Harvard, Vancouver, ISO, and other styles
You might also be interested in the extended bibliographies on the topic 'Model lipid membrane' for particular source types:
Journal articles Dissertations / Theses Books
We offer discounts on all premium plans for authors whose works are included in thematic literature selections. Contact us to get a unique promo code!

To the bibliography