Academic literature on the topic 'Phospholipids/biological membranes'
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Journal articles on the topic "Phospholipids/biological membranes"
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Solís-Calero, Christian, Joaquín Ortega-Castro, Juan Frau, and Francisco Muñoz. "Nonenzymatic Reactions above Phospholipid Surfaces of Biological Membranes: Reactivity of Phospholipids and Their Oxidation Derivatives." Oxidative Medicine and Cellular Longevity 2015 (2015): 1–22. http://dx.doi.org/10.1155/2015/319505.
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Phospholipids play multiple and essential roles in cells, as components of biological membranes. Although phospholipid bilayers provide the supporting matrix and surface for many enzymatic reactions, their inherent reactivity and possible catalytic role have not been highlighted. As other biomolecules, phospholipids are frequent targets of nonenzymatic modifications by reactive substances including oxidants and glycating agents which conduct to the formation of advanced lipoxidation end products (ALEs) and advanced glycation end products (AGEs). There are some theoretical studies about the mechanisms of reactions related to these processes on phosphatidylethanolamine surfaces, which hypothesize that cell membrane phospholipids surface environment could enhance some reactions through a catalyst effect. On the other hand, the phospholipid bilayers are susceptible to oxidative damage by oxidant agents as reactive oxygen species (ROS). Molecular dynamics simulations performed on phospholipid bilayers models, which include modified phospholipids by these reactions and subsequent reactions that conduct to formation of ALEs and AGEs, have revealed changes in the molecular interactions and biophysical properties of these bilayers as consequence of these reactions. Then, more studies are desirable which could correlate the biophysics of modified phospholipids with metabolism in processes such as aging and diseases such as diabetes, atherosclerosis, and Alzheimer’s disease.
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Brea, Roberto J., Andrew K. Rudd, and Neal K. Devaraj. "Nonenzymatic biomimetic remodeling of phospholipids in synthetic liposomes." Proceedings of the National Academy of Sciences 113, no. 31 (July 20, 2016): 8589–94. http://dx.doi.org/10.1073/pnas.1605541113.
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Cell membranes have a vast repertoire of phospholipid species whose structures can be dynamically modified by enzymatic remodeling of acyl chains and polar head groups. Lipid remodeling plays important roles in membrane biology and dysregulation can lead to disease. Although there have been tremendous advances in creating artificial membranes to model the properties of native membranes, a major obstacle has been developing straightforward methods to mimic lipid membrane remodeling. Stable liposomes are typically kinetically trapped and are not prone to exchanging diacylphospholipids. Here, we show that reversible chemoselective reactions can be harnessed to achieve nonenzymatic spontaneous remodeling of phospholipids in synthetic membranes. Our approach relies on transthioesterification/acyl shift reactions that occur spontaneously and reversibly between tertiary amides and thioesters. We demonstrate exchange and remodeling of both lipid acyl chains and head groups. Using our synthetic model system we demonstrate the ability of spontaneous phospholipid remodeling to trigger changes in vesicle spatial organization, composition, and morphology as well as recruit proteins that can affect vesicle curvature. Membranes capable of chemically exchanging lipid fragments could be used to help further understand the specific roles of lipid structure remodeling in biological membranes.
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Alves, Ana Catarina, Daniela Ribeiro, Miguel Horta, José L. F. C. Lima, Cláudia Nunes, and Salette Reis. "A biophysical approach to daunorubicin interaction with model membranes: relevance for the drug's biological activity." Journal of The Royal Society Interface 14, no. 133 (August 2017): 20170408. http://dx.doi.org/10.1098/rsif.2017.0408.
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Daunorubicin is extensively used in chemotherapy for diverse types of cancer. Over the years, evidence has suggested that the mechanisms by which daunorubicin causes cytotoxic effects are also associated with interactions at the membrane level. The aim of the present work was to study the interplay between daunorubicin and mimetic membrane models composed of different ratios of 1,2-dimyristoyl- sn -glycero- 3 -phosphocholine (DMPC), sphingomyelin (SM) and cholesterol (Chol). Several biophysical parameters were assessed using liposomes as mimetic model membranes. Thereby, the ability of daunorubicin to partition into lipid bilayers, its apparent location within the membrane and its effect on membrane fluidity were investigated. The results showed that daunorubicin has higher affinity for lipid bilayers composed of DMPC, followed by DMPC : SM, DMPC : Chol and lastly by DMPC : SM : Chol. The addition of SM or Chol into DMPC membranes not only increases the complexity of the model membrane but also decreases its fluidity, which, in turn, reduces the amount of anticancer drug that can partition into these mimetic models. Fluorescence quenching studies suggest a broad distribution of the drug across the bilayer thickness, with a preferential location in the phospholipid tails. The gathered data support that daunorubicin permeates all types of membranes to different degrees, interacts with phospholipids through electrostatic and hydrophobic bonds and causes alterations in the biophysical properties of the bilayers, namely in membrane fluidity. In fact, a decrease in membrane fluidity can be observed in the acyl region of the phospholipids. Ultimately, such outcomes can be correlated with daunorubicin's biological action, where membrane structure and lipid composition have an important role. In fact, the results indicate that the intercalation of daunorubicin between the phospholipids can also take place in rigid domains, such as rafts that are known to be involved in different receptor processes, which are important for cellular function.
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Hatch, Grant M. "Cell biology of cardiac mitochondrial phospholipids." Biochemistry and Cell Biology 82, no. 1 (February 1, 2004): 99–112. http://dx.doi.org/10.1139/o03-074.
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Phospholipids are important structural and functional components of all biological membranes and define the compartmentation of organelles. Mitochondrial phospholipids comprise a significant proportion of the entire phospholipid content of most eukaroytic cells. In the heart, a tissue rich in mitochondria, the mitochondrial phospholipids provide for diverse roles in the regulation of various mitochondrial processes including apoptosis, electron transport, and mitochondrial lipid and protein import. It is well documented that alteration in the content and fatty acid composition of phospholipids within the heart is linked to alterations in myocardial electrical activity. In addition, reduction in the specific mitochondrial phospholipid cardiolipin is an underlying biochemical cause of Barth Syndrome, a rare and often fatal X-linked genetic disease that is associated with cardiomyopathy. Thus, maintenance of both the content and molecular composition of phospholipids synthesized within the mitochondria is essential for normal cardiac function. This review will focus on the function and regulation of the biosynthesis and resynthesis of mitochondrial phospholipids in the mammalian heart.Key words: phospholipid, metabolism, heart, cardiolipin, mitochondria.
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Wang, Bo, and Peter Tontonoz. "Phospholipid Remodeling in Physiology and Disease." Annual Review of Physiology 81, no. 1 (February 10, 2019): 165–88. http://dx.doi.org/10.1146/annurev-physiol-020518-114444.
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Phospholipids are major constituents of biological membranes. The fatty acyl chain composition of phospholipids determines the biophysical properties of membranes and thereby affects their impact on biological processes. The composition of fatty acyl chains is also actively regulated through a deacylation and reacylation pathway called Lands’ cycle. Recent studies of mouse genetic models have demonstrated that lysophosphatidylcholine acyltransferases (LPCATs), which catalyze the incorporation of fatty acyl chains into the sn-2 site of phosphatidylcholine, play important roles in pathophysiology. Two LPCAT family members, LPCAT1 and LPCAT3, have been particularly well studied. LPCAT1 is crucial for proper lung function due to its role in pulmonary surfactant biosynthesis. LPCAT3 maintains systemic lipid homeostasis by regulating lipid absorption in intestine, lipoprotein secretion, and de novo lipogenesis in liver. Mounting evidence also suggests that changes in LPCAT activity may be potentially involved in pathological conditions, including nonalcoholic fatty liver disease, atherosclerosis, viral infections, and cancer. Pharmacological manipulation of LPCAT activity and membrane phospholipid composition may provide new therapeutic options for these conditions.
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Flasiński, Michał, Katarzyna Hąc-Wydro, Paweł Wydro, and Patrycja Dynarowicz-Łątka. "Influence of platelet-activating factor, lyso-platelet-activating factor and edelfosine on Langmuir monolayers imitating plasma membranes of cell lines differing in susceptibility to anti-cancer treatment: the effect of plasmalogen level." Journal of The Royal Society Interface 11, no. 95 (June 6, 2014): 20131103. http://dx.doi.org/10.1098/rsif.2013.1103.
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Three structurally related but differing in biological activities single-chained ether phospholipids (PAF (platelet-activating factor) and lyso-PAF) and an anti-cancer drug (edelfosine (ED)) were investigated in Langmuir monolayers imitating natural membranes. The aim of the undertaken experiments was to study the influence of these lipids on monolayers mimicking plasma membranes of cell lines differing in susceptibility to the anti-cancer activity of ED, i.e. promyelocytic leukaemia cells (HL-60) and promyeloblastic leukaemia cells (K-562). As these cells differ essentially in the cholesterol/phospholipid ratio and plasmalogen concentration in the membrane, we have carried out systematic investigations in artificial systems of various compositions. The results for model leukaemia cell membrane were compared with data acquired for systems imitating normal leucocytes. Our results show that the level of plasmalogens significantly modulates the influence of the single-chained phospholipids on the investigated systems. The experiments confirmed also that the interactions of ether lipids with a model membrane of HL-60 cells (in biological tests sensitive to ED) have opposite character when compared with K-562, being resistant to ED. Moreover, the values of the parameters characterizing monolayers serving as membrane models (strength of interactions, monolayers fluidity and morphology) proved both sensitivity of these cells to ED and lack of their susceptibility towards PAF. Interestingly, it has been found that lyso-PAF, which is usually described as an inactive precursor of PAF, displays a stronger effect on HL-60 model membranes than ED.
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Gamsjaeger, Roland, Alexander Johs, Anna Gries, Hermann J. Gruber, Christoph Romanin, Ruth Prassl, and Peter Hinterdorfer. "Membrane binding of β2-glycoprotein I can be described by a two-state reaction model: an atomic force microscopy and surface plasmon resonance study." Biochemical Journal 389, no. 3 (July 26, 2005): 665–73. http://dx.doi.org/10.1042/bj20050156.
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Complexes formed between β2GPI (β2-glycoprotein I), a human plasma protein, and biological membranes are considered to be targets of macrophages and antiphospholipid autoantibodies involved in autoimmune diseases, such as antiphospholipid syndrome or systemic lupus erythematosus. The positively charged lysine-rich fifth domain of β2GPI facilitates its interaction with phospholipid membranes containing acidic phospholipids, which normally become exposed by apoptotic processes. In the present study, atomic force microscopy was applied to visualize the binding of β2GPI to a mixed phospholipid model membrane at physiological ionic strength. On supported lipid bilayers the formation of supramolecular assemblies of the protein with a height of approx. 3.3 nm was observed, suggesting a lateral agglomeration of β2GPI. Detailed analysis of kinetic constants using surface plasmon resonance revealed that the binding can be described by a two-state reaction model, i.e. a very fast interaction step, depending on the content of acidic phospholipids in the bilayer, and a second step with significantly lower kon and koff values. Taken together, our results suggest a biphasic interaction mechanism: a fast step of β2GPI binding to negatively charged lipids, mainly based on electrostatic interactions, and a slower phase of agglomeration of the protein on the bilayer surface accompanied by a protein-induced rigidification of the membrane, as revealed by electron paramagnetic resonance.
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Levi, Valeria, Ana M. Villamil Giraldo, Pablo R. Castello, Juan P. F. C. Rossi, and F. Luis González Flecha. "Effects of phosphatidylethanolamine glycation on lipid–protein interactions and membrane protein thermal stability." Biochemical Journal 416, no. 1 (October 28, 2008): 145–52. http://dx.doi.org/10.1042/bj20080618.
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Non-enzymatic glycation of biomolecules has been implicated in the pathophysiology of aging and diabetes. Among the potential targets for glycation are biological membranes, characterized by a complex organization of lipids and proteins interacting and forming domains of different size and stability. In the present study, we analyse the effects of glycation on the interactions between membrane proteins and lipids. The phospholipid affinity for the transmembrane surface of the PMCA (plasma-membrane Ca2+-ATPase) was determined after incubating the protein or the phospholipids with glucose. Results show that the affinity between PMCA and the surrounding phospholipids decreases significantly after phosphospholipid glycation, but remains unmodified after glycation of the protein. Furthermore, phosphatidylethanolamine glycation decreases by ∼30% the stability of PMCA against thermal denaturation, suggesting that glycated aminophospholipids induce a structural rearrangement in the protein that makes it more sensitive to thermal unfolding. We also verified that lipid glycation decreases the affinity of lipids for two other membrane proteins, suggesting that this effect might be common to membrane proteins. Extending these results to the in vivo situation, we can hypothesize that, under hyperglycaemic conditions, glycation of membrane lipids may cause a significant change in the structure and stability of membrane proteins, which may affect the normal functioning of membranes and therefore of cells.
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Munford, M. L., V. R. Lima, T. O. Vieira, G. Heinzelmann, T. B. Creczynski-Pasa, and A. A. Pasa. "AFM In-Situ Characterization of Supported Phospholipid Layers Formed by Vesicle Fusion." Microscopy and Microanalysis 11, S03 (December 2005): 90–93. http://dx.doi.org/10.1017/s1431927605050968.
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Atomic force microscopy (AFM) is a powerful tool for direct visualization of supported biological membranes [1]. Moreover, in-situ AFM measurements permit investigations of biological phenomena in real time and in physiological environments. In a previous work, we have studied the morphology and stability of supported phospholipid layers prepared by solution spreading (casting) on mica [2]. The images were acquired in the contact or contact-intermittent modes and the samples analyzed ex-situ just after solvent evaporation and after a hydration step, and in-situ with immersion in a buffer solution. Contact-mode imaging is less suitable for soft or weakly attached materials, since the tip can often scrape or drag the membranes during scanning, a disadvantage that can be overcome by applying intermittent methods. However, studies have also demonstrated that by adjusting the operative force it is possible to use contact-mode to obtain AFM images of soft phospholipids layers [3]. In the present work, we applied successfully in-situ AFM contact-mode to characterize phospholipid layers of 1,2-dimyristoyl-sn-glycero-3-phosphatitidylcholine (DMPC) and 1,2-dioleoyl-sn-glycero-3-phosphatidylcholine (DOPC), as well as a binary mixture of these phospholipids. The supported membranes were prepared on mica substrates by vesicle fusion method.
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KITO, Makoto. "Biochemical Studies on Multifunctions of Phospholipids in Biological Membranes." Journal of the agricultural chemical society of Japan 67, no. 7 (1993): 1047–53. http://dx.doi.org/10.1271/nogeikagaku1924.67.1047.
Full textDissertations / Theses on the topic "Phospholipids/biological membranes"
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Waheed, Qaiser. "Molecular Dynamic Simulations of Biological Membranes." Doctoral thesis, KTH, Teoretisk biologisk fysik, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-102268.
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Biological membranes mainly constituent lipid molecules along with some proteins and steroles. The properties of the pure lipid bilayers as well as in the presence of other constituents (in case of two or three component systems) are very important to be studied carefully to model these systems and compare them with the realistic systems. Molecular dynamic simulations provide a good opportunity to model such systems and to study them at microscopic level where experiments fail to do. In this thesis we study the structural and dynamic properties of the pure phospholipid bilayers and the phase behavior of phospholipid bilayers when other constituents are present in them. Material and structural properties like area per lipid and area compressibility of the phospholipids show a big scatter in experiments. These properties are studied for different system sizes and it was found that the increasing undulations in large systems effect these properties. A correction was applied to area per lipid and area compressibility using the Helfrich theory in Fourier space. Other structural properties like order of the lipid chains, electron density and radial distribution functions are calculated which give the structure of the lipid bilayer along the normal and in the lateral direction. These properties are compared to the X-ray and neutron scattering experiments after Fourier transform. Thermodynamic properties like heat capacity and heat of melting are also calculated from derivatives of energies available in molecular dynamics. Heat capacity on the other hand include quantum effect and are corrected for that by applying quantum correction using normal mode analysis for a simple as well as ambiguous system like water. Here it is done for SPC/E water model. The purpose of this study is to further apply the quantum corrections on macromolecules like lipids by using this technique. Furthermore the phase behavior of two component systems (phospholipids/cholesterol) is also studied. Phase transition in these systems is observed at different cholesterol concentrations as a function of temperature by looking at different quantities (as an order parameter) like the order of chains, area per molecule and partial specific area. Radial distribution functions are used to look at the in plane structure for different phases having a different lateral or positional order. Adding more cholesterol orders the lipid chains changing a liquid disordered system into a liquid ordered one and turning a solid ordered system into a liquid ordered one. Further more the free energy of domain formation is calculated to investigate the two phasecoexistence in binary systems. Free energy contains two terms. One is bulk freeenergy which was calculated by the chemical potential of cholesterol moleculein a homogeneous system which is favorable for segregation. Second is thefree energy of having an interface which is calculated from the line tension of the interface of two systems with different cholesterol concentration which in unfavorable for domain formation. The size of the domains calculated from these two contributions to the free energy gives the domains of a few nm in size. Though we could not find any such domains by directly looking at our simulations.QC 20120913
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LADHA, PARAG. "POLYMERIC MEMBRANE SUPPORTED BILAYER LIPID MEMBRANES RECONSTITUTED WITH BIOLOGICAL TRANSPORT PROTEINS." University of Cincinnati / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1145901880.
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Ma, Xin. "The interaction between amyloid beta peptide and phospholipids." Thesis, University of Edinburgh, 2015. http://hdl.handle.net/1842/29637.
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The aim of the thesis project was to examine what form(s) of Amyloid beta (Aβ) (25-‐35) peptide interact with phospholipids in vitro and the implications of this for the mechanism of Alzheimer’s Diseases (AD). The mechanism of AD is thought to involve protein folding and misfolding. An increasing amount of evidence has shown that protein misfolding plays an important role in the biological and pathological processes of AD. Although seen as the biomedical markers of those diseases, the roles of amyloid aggregates themselves are still not fully understood. Whether the aggregates, or the monomer, or some other intermediates of Aβ cause AD is still unknown. In order to investigate the membrane-‐interaction of Aβ and its implications for AD, two forms of Aβ, namely levorotary and dextrorotary (L-‐ and D-‐) Aβ isomers were used. Evidence has shown that L-‐ and D-‐ peptide can each form aggregates in a humid environment. However, when mixed together, L-‐ and D-‐ peptides tend not to form any aggregates. Using the mixtures of L-‐ and D-‐ peptides at different proportions and as well as using L-‐ and D-‐ alone can help us to determine the toxic form of Aβ. Phospholipids have been used to mimic membrane bilayers. Biological membranes in vivo are a complicated system. They contain three types of lipids, namely phospholipids, glycolipids, and steroids. Different types of cells and different membranes have different proportions of those lipids. Studying the interaction between Aβ and membranes in vivo can be extremely difficult. Artificial membranes, which only contains one kind of lipids, on the other hand, are a useful tool for the study of molecular interactions. Phospholipids are the most abundant type of membrane lipid and thus that can be seen as representative of cell membranes. The interactions of Aβ and different kinds of phospholipids have been investigated in this project. This thesis discusses the secondary structure of Aβ in different environment, the interaction between Aβ and phospholipids at the air-‐water surface, and the location of Aβ in membranes during the interaction. The study provides useful information of the mechanisms and the origin of AD. At the end of the thesis, a discussion chapter analyses the difficulties of studying Aβ and AD and the potentials and inadequacies of this research.
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Duralski, Andrzej Antoni. "Synthesis and biophysical studies of cardiolipin." Thesis, University of Oxford, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.279885.
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Mason, Peter C. "Small angle scattering studies of phospholipids in excess water /." *McMaster only, 1998.
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Leekumjorn, Sukit. "Molecular Dynamics Simulations for the Study of Biophysical Processes on Biological Membranes." Diss., Virginia Tech, 2008. http://hdl.handle.net/10919/29180.
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Phospholipid bilayers constitute the primary structural element of biological membranes, and as such, they play a central role in biochemical and biophysical processes at the cellular level, including cell protection, intercellular interactions, trans-membrane transport, cell morphology, and protein function, to name a few. The properties of phospholipid bilayers are thus of great interest from both experimental and theoretical standpoints. Although experiments have provided much of the macroscopic functions and properties of biological membranes, insight into specific mechanisms at the molecular level are seldom accessible by conventional methods. To obtain a better understanding of biochemical and biophysical processes at the molecular level involving phospholipid bilayers, we apply molecular simulation methods to investigate the complexity of the membrane matrix using atomistic models. Here, we discuss three specific biological processes that are associated with biological membranes: 1) membrane stabilization, 2) membrane phase behavior, and 3) fatty acid-induced toxicity in cell membranes.
For membrane stabilization, molecular dynamics studies were performed for mixed phospholipid bilayers containing two of the most prevalent phospholipids (phosphatidylcholine and phosphatidylethanolamime) in biological membranes. We presented structural and dynamics properties of these systems, as well as the effect of stabilizing agents, such as trehalose, on their properties. Furthermore, we performed a comprehensive analysis of the phase transition of lipid bilayers and investigated the interactions of stabilizing agents (glucose or trehalose) with lipid bilayers under dehydrated conditions to understand the mechanisms for preservation of cellular systems.
For membrane phase behavior, a comprehensive study of the structural properties of saturated and monounsaturated lipid bilayers near the main phase transition were investigated using molecular dynamics simulations. In this study, we demonstrated that atomistic simulations are capable of capturing the phase transformation process of lipid bilayers, providing a valuable set of molecular and structural information at and near its transition state.
Lastly, the third study investigated the mechanism for fatty acid-induced toxicity by integrating in vitro and in silico experiments to reveal the biophysical interactions of saturated fatty acid (palmitate) with the cellular membranes and the role of trehalose and unsaturated fatty acids (oleate and linoleate) in preventing changes to the membrane structure. Knowledge gained from this study is essential in the prevention and treatment of obesity-associated cirrhosis diseases.Ph. D.
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Ribeiro, Cristiéle da Silva. "A influência térmica na dinâmica das membranas celulares: uma contribuição na conservação de Steindachneridion parahybae (Siluriformes: Pimelodidae), uma espécie de peixe ameaçada de extinção." Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/41/41135/tde-24082012-154629/.
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A temperatura é o fator ambiental mais importante que afeta a atividade de animais ectotérmicos, como peixes. Ajustes compensatórios à temperatura ocorrem em diferentes cursos temporais, que variam de menos de um minuto a mais de um mês, e as membranas são os primeiros alvos afetados pelas mudanças de temperatura, com resposta imediata dos componentes lipídicos a este desafio. Este trabalho teve como objetivo estimar a capacidade alostática (na estrutura e funções de membrana) no contexto das variáveis climáticas relevantes e caracterizar o âmbito e os mecanismos de mudança, incluindo os mecanismos que concedem tolerância a mudanças de temperatura agudas e crônicas. Juvenis de Steindachneridion parahybae uma espécie de peixe nativa ameaçada de extinção, foram progressivamente resfriados de 30° C a 24, 17 e 12 ° C, nas quais foram mantidas por até 5 dias no tratamento agudo e por até 30 dias no tratamento crônico. Os tecidos hepático, encefálico e branquial foram amostrados, com análises subsequentes das principais frações fosfolipídicas (fosfatidilcolina (FC) e fosfatidiletanolamina (FE) e análises posicionais de cada fração), atividade da Na+/ K+-ATPase e histomorfologia branquial. Os animais mantidos na temperatura mais baixa mostraram uma elevada taxa de mortalidade, provavelmente devido à proximidade desta temperatura ao limite térmico inferior para esta espécie. A atividade da Na+/ K+-ATPase se mostrou aumentada nas temperaturas mais baixas, corroborando o aumento das lesões morfológicas branquiais e massa de fígado para estas temperaturas. Em geral o perfil de ácidos graxos de FC mantiveram-se mais estáveis do que o observado para FE. O teste agudo aparentemente afetou consideravelmente C20-22n3 (FC hepática e sn-1 ; FE encefálica e hepática), enquanto que no teste crônico, C20-22n6 foi o grupamento mais afetado (FC e FE hepático em sn-2 e sn-1). O ensaio agudo mostrou um padrão de manutenção da estrutura de membrana cerebral, com uma diminuição de C20-22n3 hepática e aumento destes ácidos graxos no encéfalo durante o tratamento. Em ambos os tecidos e frações analisados foi possível detectar evidências significativas de reestruturação da membrana, mostrando que o Surubim do Paraíba foi capaz de proporcionar ajustes compensatórios em respostas de aclimatação.Temperature is the most important environmental factor affecting the activity of ectothermic animals such as fish. Compensatory adjustments to temperature occur with time courses ranging from less than a minute to more than a month, and membranes are the first targets affected by change of temperature, and their lipid components respond immediately to this challenge. This project aimed to estimate the allostatic capacity (in membrane structure and function) in the context of relevant climate variables, and to characterize the scope and the defense mechanisms available, including those yielding tolerance to acute and chronic temperature shifts. Steindachneridion parahybae juveniles, an endangered native fish species, were progressively cooled from 30°C to 24, 17 and 12°C, in which they were maintained for up to 5 days in the acute trial and for up 30 days in the chronic trial. Brain, liver and branchial tissues were sampled, with subsequent analyses of the main phospholipids fractions (phosphatidylcholine (PC) and phosphatidylethanolamine (PE), and the positional analyses of each fraction), Na+/K+-ATPase activity and histomorphology of gills. The animals maintained atlower temperature showed a high rate of mortality, probably because this temperature is near the lower thermal limit for this species. The activity of Na+ K+ATPase increased at lower temperatures, the same pattern observed for morphological injuries in gills and increased liver mass. Generally the fatty acid profiles of PC remained more stable than those in PE. The acute test apparently had affected considerably C20-22n3 (liver PC and sn-1 PC; PE in brain and liver), while for the chronic test, C20-22n6 was more affected (PC and PE liver on sn-2 and sn-1). The acute trial showed a pattern of maintenance of brain membrane structure, with a decrease of PE-associated C20-22n3 in the liver and an increase of these fatty acids in brain during the test. In both tissues and fractions analyzed it was possible to detect significant evidences of membrane restructuring, showing that the Surubim do Paraiba was able to provide compensatory adjustments in acclimation responses
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Biederman, Amanda M. "Characterizing the Link between Biological Membranes and Thermal Physiology in Antarctic Notothenioid Fishes." Ohio University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1561993742334324.
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El, Achkar Tracy. "Deep eutectic solvents : characterization, interaction with synthetic and biological membranes, and solubilization of bioactive volatile compounds." Thesis, Littoral, 2020. http://www.theses.fr/2020DUNK0562.
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Les solvants eutectiques profonds (DES) sont récemment apparus comme une nouvelle classe de solvants verts présentant un potentiel élevé pour remplacer les solvants organiques usuels. Bien que découverts récemment, les DES ont fait l'objet de nombreuses recherches au cours des dernières années en raison de leurs propriétés intéressantes. Cependant, il reste encore beaucoup à découvrir étant donné le nombre quasiment illimité de DES potentiels et de leur polyvalence. Notre étude vise à examiner l'effet des DES sur les liposomes, adoptés comme modèles membranaires, et sur les membranes cellulaires. Elle a également cherché à évaluer la capacité de solubilisation des DES envers des composés bioactifs volatils. Ainsi, une sélection de DES ainsi que de nouveaux solvants ont été tout d'abord préparés et caractérisés. Des mesures de densité, de viscosité et de polarité ont été effectuées et ont montrées que les propriétés des DES pouvaient être ajustées en fonction de leur composition. L'organisation des phospholipides et des liposomes au sein des DES a ensuite été étudiée à l'aide de microscopies optique et à force atomique. Les phospholipides s'auto-assemblent en vésicules dans les DES à base de chlorure de choline tandis que les liposomes se convertissent en bicouches lipidiques avant leur reconstitution en vésicules. De plus, des études de cytotoxicité et des examens morphologiques ont été combinés afin d'évaluer l'impact de quelques DES sur MDA-MB-231, une lignée cellulaire de cancer du sein humain. Les résultats ont montrés que l'effet dépendait fortement de la composition du DES. D'autre part, la capacité de solubilisation des DES envers des composés bioactifs volatils a été testée par chromatographie en phase gazeuse couplée à un espace de tête. L'influence de la présence d'eau et de certains systèmes d'encapsulation tels que les liposomes et les cyclodextrines sur la capacité de solubilisation des DES ont été analysés. Enfin, la libération du trans-anéthole à partir des DES a été suivie par extraction multiple de l'espace de tête. Les DES ont été capables de mieux solubiliser les composés bioactifs volatils et de contrôler leur libération par rapport à l'eau. Dans l'ensemble, ces travaux mettent en évidence l'utilisation potentielle des systèmes à base de DES comme véhicules de solubilisation de composés bioactifsDeep eutectic solvents (DES) recently emerged as a novel class of green solvents with a high potential to replace common organic solvents. Despite their novelty, DES were extensively explored in the past years owing to their remarkably interesting properties. Yet, a lot remains to be uncovered given the limitless number of possible DES and their versatility. The current sudy aimed to examine the effect of DES on liposomes, adopted as model membranes, and on cell membranes. It also sought to evaluate the solubilizing ability of DES toward bbioactive volatile compounds. Therefore, a group of selected DES along with new solvents were first prepared and characterized. Density, viscosity and polarity measurements were mainly carried out and showed that DES' properties can be tuned depending on their composition. The organization of phospholipids and liposomes within the DES was then investigated using optical- and atomical force microscopies. Phospholipids self-assembled into vesicles in choline chloride-based DES while liposomes converted to lipid bilayers before their reconstitution into vesicles. Moreover, cytotoxicity studies and morphological examinations were combined to evaluate the impact of some DES on MDA-MB-231, a human breast cancer cell line. Results showed that the effect is highly dependent on the DES' composition. On the other hand, the solubilizing ability of the DES toward bioactive volatile compounds was tested using static headspace-gas chromatography. The influence of the presence of water and some encapsulation systems such as liposomes and cyclodextrins on the overall DES' solubilization efficiency was further analyzed. At last, the release of trans-anethole from the DES was monitored via multiple headspace extraction. DES were able to greatly solubilize the bioactive volatile compounds and to control their release when compared with water. Altogether, this work highlights the potential use of the DES-based systems as solubilization vehicles for bioactive compounds
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Weinberger, Andreas. "Systèmes modèles de membranes et potentiel de pénétration de polypeptides." Phd thesis, Université de Strasbourg, 2013. http://tel.archives-ouvertes.fr/tel-01065966.
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Les vésicules géantes unilamellaires (GUV) permettent d'étudier efficacement les interactions entre les lipides et les peptides. Dans ce manuscrit, il a été montré que les interactions attractives lipides-peptides sont supprimées par l'attachement de polypeptides de type élastine (ELP) sur des peptides riches en arginine et peuvent être modulées par l'auto-assemblage en micelles ainsi que par le nombre de groupements arginine dans la séquence des peptides capables de pénétrer les cellules. De plus, une nouvelle méthode pour former des GUV à partir de systèmes complexes en seulement quelques minutes a été développée. Cette méthode est basée sur le gonflement d'un film de PVA sous une bicouche lipidique. Elle supprime la dégradation des molécules pendant la formation des GUV de lipides synthétiques, tels que des glycolipides et des phospholipides portant des groupements amides, où les méthodes traditionnelles ne réussissent pas à produire des vésicules non endommagées.
Books on the topic "Phospholipids/biological membranes"
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Derek, Marsh, ed. Phospholipid bilayers: Physical principles and models. New York: Wiley, 1987.
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Hanahan, Donald J. A Guide to Phospholipid Chemistry. Oxford University Press, 1997. http://dx.doi.org/10.1093/oso/9780195079814.001.0001.
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This book provides a concise introduction to phospholipid chemistry and is intended for a broad audience of biologists, biochemists, and graduate students. Developed as part of a graduate course on lipids, this book also serves as a reference for laboratory investigators on signal transduction and biological membranes. The first part of the text is devoted to an orientation to the chemical nature of lipids in general, how they are thought to be associated in the cell, and the methodology by which the cellular lipids (including the phospholipids) can be recovered from cells and subjected to an initial identification. Subsequent chapters characterize the choline-containing phospholipids, including the sphingolipids, the non-choline containing phospholipids, and finally, the so-called minor phospholipids. The latter compounds, which act as agonists or lipid chemical mediators on cells, form a vanguard of a new category of biologically active substances and have set the study of cellular phospholipids on a new and exiting course. Most importantly, this book provides a basis for further inquiry on these complicated molecules, showing that although the compounds are unique, with care and understanding, they can be studied with ease
Book chapters on the topic "Phospholipids/biological membranes"
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Schlenkrich, Michael, Jürgen Brickmann, Alexander D. MacKerell, and Martin Karplus. "An Empirical Potential Energy Function for Phospholipids: Criteria for Parameter Optimization and Applications." In Biological Membranes, 31–81. Boston, MA: Birkhäuser Boston, 1996. http://dx.doi.org/10.1007/978-1-4684-8580-6_2.
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Dowhan, William. "Role of Phospholipids in Cell Function." In Biological Membranes: Structure, Biogenesis and Dynamics, 1–21. Berlin, Heidelberg: Springer Berlin Heidelberg, 1994. http://dx.doi.org/10.1007/978-3-642-78846-8_1.
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Op den Kamp, J. A. F., E. Middelkoop, R. J. Ph Musters, J. A. Post, B. Roelofsen, and A. J. Verkleij. "Localization of Phospholipids in Plasma Membranes of Mammalian Cells." In Biological Membranes: Structure, Biogenesis and Dynamics, 33–41. Berlin, Heidelberg: Springer Berlin Heidelberg, 1994. http://dx.doi.org/10.1007/978-3-642-78846-8_3.
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Roux, Benoît, and Thomas B. Woolf. "Molecular Dynamics of Pf1 Coat Protein in a Phospholipid Bilayer." In Biological Membranes, 555–87. Boston, MA: Birkhäuser Boston, 1996. http://dx.doi.org/10.1007/978-1-4684-8580-6_17.
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Zubenko, George S. "Biological Markers of Alzheimer’s Disease: A View from the Perspective of Phospholipids in Membrane Function." In Phospholipids, 205–11. Boston, MA: Springer US, 1990. http://dx.doi.org/10.1007/978-1-4757-1364-0_16.
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Mendelsohn, Richard, and Robert G. Snyder. "Infrared Spectroscopic Determination of Conformational Disorder and Microphase Separation in Phospholipid Acyl Chains." In Biological Membranes, 145–74. Boston, MA: Birkhäuser Boston, 1996. http://dx.doi.org/10.1007/978-1-4684-8580-6_6.
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Girault, L., P. Lemaire, A. Boudou, and E. J. Dufourc. "Inorganic Mercury Interactions with Lipid Components of Biological Membranes: 31P-NMR Study of Hg(II) Binding to Headgroups of Micellar Phospholipids." In Mercury as a Global Pollutant, 95–98. Dordrecht: Springer Netherlands, 1995. http://dx.doi.org/10.1007/978-94-011-0153-0_11.
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Verkleij, A. J. "Role of Lipids During Fusion of Model and Biological Membranes." In Phospholipid Research and the Nervous System, 207–16. New York, NY: Springer New York, 1986. http://dx.doi.org/10.1007/978-1-4899-0490-4_20.
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Herrmann, Andreas, Alain Zachowski, Phillipe F. Devaux, and Robert Blumenthal. "Control of Fusion of Biological Membranes by Phospholipid Asymmetry." In Cell and Model Membrane Interactions, 89–113. Boston, MA: Springer US, 1991. http://dx.doi.org/10.1007/978-1-4615-3854-7_6.
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Albrecht, Otto, David S. Johnston, Carmen Villaverde, and Dennis Chapman. "Stable Biomembrane Surfaces Formed by Phospholipid Polymers." In Physical Methods on Biological Membranes and Their Model Systems, 297–303. Boston, MA: Springer US, 1985. http://dx.doi.org/10.1007/978-1-4684-7538-8_22.
Full textConference papers on the topic "Phospholipids/biological membranes"
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Basham, Colin, Megan Pitz, Joseph Najem, Stephen Sarles, and Md Sakib Hasan. "Memcapacitive Devices in Neuromorphic Circuits via Polymeric Biomimetic Membranes." In ASME 2019 Conference on Smart Materials, Adaptive Structures and Intelligent Systems. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/smasis2019-5648.
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Abstract Two-terminal adaptive materials and circuit elements that mimic the signal processing, learning, and computing capabilities of biological synapses are essential for next-generation computing systems. To this end, we have recently developed resistive (ion channel) and capacitive (lipid bilayer) memory elements that mimic the composition, structure, and plasticity of biological synapses. Unlike solid-state counterparts, these biomolecular systems are low-power, analog, less noisy, biocompatible, and capable of exhibiting multiple timescales of short-term synaptic plasticity. However, lipid membranes lack structural stability and modularity necessary for a long-lasting adaptive material system. To address this issue, we propose the replacement of phospholipids with amphiphilic polymers to create artificial membranes, which have been demonstrated to be more durable than phospholipids. With the focus on memory capacitors, we demonstrate that polymeric bilayers can exhibit pinched hysteresis in the Q-v plane because of voltage-induced geometrical changes. Further, we demonstrate that the memcapacitive response is altered based on the surrounding oil medium; smaller oil molecules are retained at higher volume in the membrane, so that thicker bilayers have lower nominal capacitance but can vary this value by over 400%. Finally, we present a physics-based model that enables us to predict the device’s areal voltage-dependent response. Polymeric bilayers represent a significant enhancement in the field of soft-matter, geometrically-reconfigurable memcapacitors, and their highly customizable compositions will allow for a finely tuned electrical response that has a future in brain-inspired materials and circuits.
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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.
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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.