Artykuły w czasopismach: „Dynamic membranes”

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Madmoune, Y., M. Benhamou, H. Kaïdi i M. Chahid. "Dynamic properties of troubled fluid membranes". International Journal of Academic Research 5, nr 5 (10.10.2013): 5–13. http://dx.doi.org/10.7813/2075-4124.2013/5-5/a.1.

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Bezanilla, Magdalena, Amy S. Gladfelter, David R. Kovar i Wei-Lih Lee. "Cytoskeletal dynamics: A view from the membrane". Journal of Cell Biology 209, nr 3 (11.05.2015): 329–37. http://dx.doi.org/10.1083/jcb.201502062.

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Many aspects of cytoskeletal assembly and dynamics can be recapitulated in vitro; yet, how the cytoskeleton integrates signals in vivo across cellular membranes is far less understood. Recent work has demonstrated that the membrane alone, or through membrane-associated proteins, can effect dynamic changes to the cytoskeleton, thereby impacting cell physiology. Having identified mechanistic links between membranes and the actin, microtubule, and septin cytoskeletons, these studies highlight the membrane’s central role in coordinating these cytoskeletal systems to carry out essential processes, such as endocytosis, spindle positioning, and cellular compartmentalization.

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Matkó, Janos, Janos Szöllösi, Lajos Trón i Sandor Damjanovich. "Luminescence spectroscopic approaches in studying cell surface dynamics". Quarterly Reviews of Biophysics 21, nr 4 (listopad 1988): 479–544. http://dx.doi.org/10.1017/s0033583500004637.

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The major elements of membranes, such as proteins, lipids and polysaccharides, are in dynamic interaction with each other (Albertset al.1983). Protein diffusion in the lipid matrix of the membrane, the lipid diffusion and dynamic domain formation below and above their transition temperature from gel to fluid state, have many functional implications. This type of behaviour of membranes is often summarized in one frequently used word membrane fluidity (coined by Shinitzky & Henkart, 1979). The dynamic behaviour of the cell membrane includes rotational, translational and segmental movements of membrane elements (or their domain-like associations) in the plane of, and perpendicular to the membrane. The ever changing proximity relationships form a dynamic pattern of lipids, proteins and saccharide moieties and are usually described as ‘cell-surface dynamics’ (Damjanovichet al.1981). The knowledge about the above defined behaviour originates from experiments performed mostly on cytoplasmic membranes of eukaryotic cells. Nevertheless numerous data are available also on the mitochondrial and nuclear membranes, as well as endo (sarco-)plasmic reticulum (Martonosi, 1982; Slater, 1981; Siekevitz, 1981).

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Liu, Chuang, i Linan Fan. "Evolutionary algorithm based on dynamical structure of membrane systems in uncertain environments". International Journal of Biomathematics 09, nr 02 (14.01.2016): 1650017. http://dx.doi.org/10.1142/s1793524516500170.

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In this paper, a new evolutionary algorithm based on a membrane system is proposed to solve the dynamic or uncertain optimization problems. The proposed algorithm employs objects, a dynamical membrane structure and several reaction rules of the membrane systems. The object represents a candidate solution of the optimization problems. The dynamical structure consists of the nested membranes where a skin membrane contains several membranes, which is useful for the proposed algorithm that finds optimal solutions. The reaction rules are designed to locate and track the optimal solutions of the dynamic optimization problems (DOPs), which are inspired by processing the chemical compounds in the region of cellular membranes. Experimental study is conducted based on the moving peaks benchmark to evaluate the performance of the proposed algorithm in comparison with three state-of-the-art dynamic optimization algorithms. The results indicate the proposed algorithm is effective to solve the DOPs.

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Gupta, Sudipta, i Rana Ashkar. "The dynamic face of lipid membranes". Soft Matter 17, nr 29 (2021): 6910–28. http://dx.doi.org/10.1039/d1sm00646k.

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Lipid membranes envelope live cells and mediate vital biological functions through regulated spatiotemporal dynamics. This review highlights the role of neutron scattering, among other approaches, in uncovering the dynamic properties of lipid membranes.

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Altman, Marc, David Hasson i Raphael Semiat. "REVIEW OF DYNAMIC MEMBRANES". Reviews in Chemical Engineering 15, nr 1 (styczeń 1999): 1–40. http://dx.doi.org/10.1515/revce.1999.15.1.1.

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Jaksch, Sebastian, Alexandros Koutsioubas, Stefan Mattauch, Olaf Holderer i Henrich Frielinghaus. "Measurements of Dynamic Contributions to Coherent Neutron Scattering". Colloids and Interfaces 2, nr 3 (7.08.2018): 31. http://dx.doi.org/10.3390/colloids2030031.

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In this manuscript, we are investigating the contribution of dynamic membrane properties of phospholipid membranes to coherent scattering signals under grazing incidence. Spectroscopic measurements under grazing incidence can provide useful insight into the properties of biological membranes; however, they are often impeded by weak signals. By using grazing-incidence small-angle neutron scattering (GISANS) to identify a dynamic scattering contribution, we are able to independently corroborate the existence of a previously found dynamic mode, now measured by grazing-incidence neutron spin echo spectroscopy (GINSES). Additionally, by increasing the speed of measurement compared to GINSES from several days to hours, we were able to explore the temperature behavior of this mode in phospholipid membranes. These dynamic modes of the membranes show a wavelength of around 700 Å in-plane of the membrane and are most pronounced around 37 ∘C and strongly decrease at lower temperatures below 25 ∘C before vanishing at 20 ∘C. We therefore speculate that they may be linked to biologically relevant functions of the membranes themselves. To our knowledge, this is the first report of an investigation of that membrane mode by means of GISANS.

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Colom, Adai, Lorena Redondo-Morata, Nicolas Chiaruttini, Aurélien Roux i Simon Scheuring. "Dynamic remodeling of the dynamin helix during membrane constriction". Proceedings of the National Academy of Sciences 114, nr 21 (8.05.2017): 5449–54. http://dx.doi.org/10.1073/pnas.1619578114.

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Dynamin is a dimeric GTPase that assembles into a helix around the neck of endocytic buds. Upon GTP hydrolysis, dynamin breaks these necks, a reaction called membrane fission. Fission requires dynamin to first constrict the membrane. It is unclear, however, how dynamin helix constriction works. Here we undertake a direct high-speed atomic force microscopy imaging analysis to visualize the constriction of single dynamin-coated membrane tubules. We show GTP-induced dynamic rearrangements of the dynamin helix turns: the average distances between turns reduce with GTP hydrolysis. These distances vary, however, over time because helical turns were observed to transiently pair and dissociate. At fission sites, these cycles of association and dissociation were correlated with relative lateral displacement of the turns and constriction. Our findings show relative longitudinal and lateral displacements of helical turns related to constriction. Our work highlights the potential of high-speed atomic force microscopy for the observation of mechanochemical proteins onto membranes during action at almost molecular resolution.

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Lima-Rodriguez, Antonia, Antonio Gonzalez-Herrera i Jose Garcia-Manrique. "Study of the Dynamic Behaviour of Circular Membranes with Low Tension". Applied Sciences 9, nr 21 (5.11.2019): 4716. http://dx.doi.org/10.3390/app9214716.

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The dynamic behaviour of membranes has been widely studied by well-known authors for a long time. A clear distinction can be made between the behaviour of membranes without tension (plate case) and membranes subjected to large tension or pre-strain in their plane (membrane case). In classical theories, less attention has been paid to membranes subjected to a low level of tension, which solution is between both extreme cases. Recently, certain fields of research are demanding solutions for this intermediate behaviour. It is the case of membranes present in MEMS and sensor or the response of the tympanic membrane in mammals hearing system. In this paper, the behaviour of plates and circular membranes with boundary conditions clamped in the edges has been studied. The natural frequencies for both cases (plate and membrane) have been calculated using the solutions of the traditional theories and these have been compared with the numerical frequencies calculated by finite element analysis. The dynamic response of membrane with low tension, corresponding to a transition between these extreme behaviours, has also been calculated. A theoretical solution has been used complemented with a wide set of numerical finite elements calculations. The analytical and numerical solutions are very close, being the error made using both methods very low; nevertheless, there are no analytical solutions for the entire transition zone between the plate and membrane behaviour. Therefore, this range has been completed using finite element analysis. Broad ranges of geometric configurations have been studied. The transition behaviour of the membrane has been clearly identified. The main practical consequences of these results have been discussed, in particular focused on the response of the tympanic membrane.

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Kanagabasai, Lenin. "Factual power loss reduction by dynamic membrane evolutionary algorithm". International Journal of Advances in Applied Sciences 10, nr 2 (1.06.2021): 99. http://dx.doi.org/10.11591/ijaas.v10.i2.pp99-106.

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This paper presents Dynamic Membrane Evolutionary Algorithm (DMEA) has been applied to solve optimal reactive power problem.Proposed methodology merges the fusion and division rules of P systems with active membranes and with adaptive differential evolution (ADE), particle swarm optimization (PSO) exploration stratagem. All elementary membranes are amalgamated into one membrane in the computing procedure. Furthermore, integrated membrane are alienated into the elementary membranes 1, 2,_ m. In particle swarm optimization (PSO) 𝑪𝟏, 𝑪𝟐 (acceleration constants) are vital parameters to augment the explorationability of PSO in the period ofthe optimization procedure.In this work, Gaussian probability distribution isinitiated to engenderthe accelerating coefficients of PSO.Proposed Dynamic Membrane Evolutionary Algorithm (DMEA) has been tested in standard IEEE 14, 30, 57, 118, 300 bus test systems and simulation results show the projected algorithm reduced the real power loss comprehensively.

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Jenkins, Paul M., Meng He i Vann Bennett. "Dynamic spectrin/ankyrin-G microdomains promote lateral membrane assembly by opposing endocytosis". Science Advances 1, nr 8 (wrzesień 2015): e1500301. http://dx.doi.org/10.1126/sciadv.1500301.

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Current physical models for plasma membranes emphasize dynamic 10- to 300-nm compartments at thermodynamic equilibrium but subject to thermal fluctuations. However, epithelial lateral membranes contain micrometer-sized domains defined by an underlying membrane skeleton composed of spectrin and its partner ankyrin-G. We demonstrate that these spectrin/ankyrin-G domains exhibit local microtubule-dependent movement on a time scale of minutes and encounter most of the lateral membranes within an hour. Spectrin/ankyrin-G domains exclude clathrin and clathrin-dependent cargo, and inhibit both receptor-mediated and bulk endocytosis. Moreover, inhibition of endocytosis fully restores lateral membrane height in spectrin- or ankyrin-G–depleted cells. These findings support a non-equilibrium cellular-scale model for epithelial lateral membranes, where spectrin/ankyrin-G domains actively patrol the plasma membrane, analogous to “window washers,” and promote columnar morphology by blocking membrane uptake.

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Nechifor, G., Mircea Olteanu, Gabriela Popescu i V. Pîrvulescu. "Dynamic Membranes for Catalytic Reaction". Key Engineering Materials 61-62 (styczeń 1992): 443–48. http://dx.doi.org/10.4028/www.scientific.net/kem.61-62.443.

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NAKATANI, Yoichi, i Guy OURISSON. "Dynamic Analysis of Lipid Membranes". Journal of Japan Oil Chemists' Society 47, nr 10 (1998): 1083–97. http://dx.doi.org/10.5650/jos1996.47.1083.

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Al-Malack, Muhammad H., i G. K. Anderson. "Cleaning techniques of dynamic membranes". Separation and Purification Technology 12, nr 1 (wrzesień 1997): 25–33. http://dx.doi.org/10.1016/s1383-5866(97)00012-9.

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Evans, Evan, i Volkmar Heinrich. "Dynamic strength of fluid membranes". Comptes Rendus Physique 4, nr 2 (marzec 2003): 265–74. http://dx.doi.org/10.1016/s1631-0705(03)00044-6.

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Maver, K., U. Lavrenčič Štangar, P. Judeinstein i J. M. Zanotti. "Dynamic studies of Ormosil membranes". Journal of Non-Crystalline Solids 354, nr 2-9 (styczeń 2008): 680–87. http://dx.doi.org/10.1016/j.jnoncrysol.2007.08.087.

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Jenkins, C. H., i J. W. Leonard. "Dynamic Wrinkling of Viscoelastic Membranes". Journal of Applied Mechanics 60, nr 3 (1.09.1993): 575–82. http://dx.doi.org/10.1115/1.2900841.

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Problems associated with viscoelastic membrane structures have been documented, e.g., dynamic wrinkling and its effects on fatigue analysis and on snap loading. In the proposed analysis method, the constitutive equation is approximated by a finite difference equation and embedded within a nonlinear finite element spatial discretization. Implicit temporal integration and a modified Newton-Raphson method are used within a time increment. The stress-strain hereditary relation is formally derived from thermodynamic considerations. Use of modified strain-energy and dissipation functions facilitates the description of wrinkling during the analysis. Applications are demonstrated on an inflated cylindrical cantilever and on a submerged cylindrical membrane excited by waves.

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Al-Malack, Muhammad H., i G. K. Anderson. "Crossflow microfiltration with dynamic membranes". Water Research 31, nr 8 (sierpień 1997): 1969–79. http://dx.doi.org/10.1016/s0043-1354(96)00313-2.

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Campelo, F., i A. HernÃ¡ndez-Machado. "Dynamic instabilities in biological membranes". PAMM 7, nr 1 (grudzień 2007): 1121403–4. http://dx.doi.org/10.1002/pamm.200700341.

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Tarun, Orly B., Christof Hannesschläger, Peter Pohl i Sylvie Roke. "Label-free and charge-sensitive dynamic imaging of lipid membrane hydration on millisecond time scales". Proceedings of the National Academy of Sciences 115, nr 16 (2.04.2018): 4081–86. http://dx.doi.org/10.1073/pnas.1719347115.

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Biological membranes are highly dynamic and complex lipid bilayers, responsible for the fate of living cells. To achieve this function, the hydrating environment is crucial. However, membrane imaging typically neglects water, focusing on the insertion of probes, resonant responses of lipids, or the hydrophobic core. Owing to a recent improvement of second-harmonic (SH) imaging throughput by three orders of magnitude, we show here that we can use SH microscopy to follow membrane hydration of freestanding lipid bilayers on millisecond time scales. Instead of using the UV/VIS resonant response of specific membrane-inserted fluorophores to record static SH images over time scales of >1,000 s, we SH imaged symmetric and asymmetric lipid membranes, while varying the ionic strength and pH of the adjacent solutions. We show that the nonresonant SH response of water molecules aligned by charge−dipole interactions with charged lipids can be used as a label-free probe of membrane structure and dynamics. Lipid domain diffusion is imaged label-free by means of the hydration of charged domains. The orientational ordering of water is used to construct electrostatic membrane potential maps. The average membrane potential depends quadratically on an applied external bias, which is modeled by nonlinear optical theory. Spatiotemporal fluctuations on the order of 100-mV changes in the membrane potential are seen. These changes imply that membranes are very dynamic, not only in their structure but also in their membrane potential landscape. This may have important consequences for membrane function, mechanical stability, and protein/pore distributions.

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Segarceanu, Mircea, Alexandra Raluca Miron, Szidonia Katalin Tanczos, Abbas Abdul Kadhim Klaif Rikabi, Ion Marius Nafliu i Danut Ionel Vaireanu. "Dynamic Membranes on Polysulfone Support for Fuel Cells". Materiale Plastice 55, nr 2 (30.06.2018): 137–40. http://dx.doi.org/10.37358/mp.18.2.4980.

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In the present paper, the authors dealt with the synthesis and characterization of a new type of dynamic membrane with polysulfone matrix and ionic polymer electrolyte: polysulfone-sulfonated polyetherether-sulfone (PSf-SPEEK). The PSf-SPEEK composite membranes were formed by ultrafiltration of SPEEK gel on the polysulfone matrix in a CELFA System installation. The thickness of the PSf porous layer for the different membranes can be between 50 and 120 mm. The variation of SPEEK active layer�s thickness is dependent both on the concentration of the SPEEK solution in the feed, and on the velocity of the surface flow. The sulfonated polymer (SPEEK) superficial layer ranges from 35 to 75 nm, being thicker at low flow rates having a slight increasing related to the increase of the SPEEK concentration. Increasing the polymer concentration, from 0.5 to 2.5%, used in the feed solution leads to a doubling of the conductivity and a tripling of the ion exchange capacity. The maximum conductivity of the PSf-SPEEK dynamic composite membranes is 0.234 S/cm and the ion exchange capacity is 1.682 meq/g.

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Busch, Karin B., Gabriele Deckers-Hebestreit, Guy T. Hanke i Armen Y. Mulkidjanian. "Dynamics of bioenergetic microcompartments". Biological Chemistry 394, nr 2 (1.02.2013): 163–88. http://dx.doi.org/10.1515/hsz-2012-0254.

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Abstract The vast majority of life on earth is dependent on harvesting electrochemical potentials over membranes for the synthesis of ATP. Generation of membrane potential often relies on electron transport through membrane protein complexes, which vary among the bioenergetic membranes found in living organisms. In order to maximize the efficient harvesting of the electrochemical potential, energy loss must be minimized, and this is achieved partly by restricting certain events to specific microcompartments, on bioenergetic membranes. In this review we will describe the characteristics of the energy-converting supramolecular structures involved in oxidative phosphorylation in mitochondria and bacteria, and photophosphorylation. Efficient function of electron transfer pathways requires regulation of electron flow, and we will also discuss how this is partly achieved through dynamic re-compartmentation of the membrane complexes into different supercomplexes. In addition to supercomplexes, the supramolecular structure of the membrane, and in particular the role of water layers on the surface of the membrane in the prevention of wasteful proton escape (and therefore energy loss), is discussed in detail. In summary, the restriction of energetic processes to specific microcompartments on bioenergetic membranes minimizes energy loss, and dynamic rearrangement of these structures allows for regulation.

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LIU, CHANG-JIANG, ZHOU-LIAN ZHENG, LONG JUN, JIAN-JUN GUO i KUI WU. "DYNAMIC ANALYSIS FOR NONLINEAR VIBRATION OF PRESTRESSED ORTHOTROPIC MEMBRANES WITH VISCOUS DAMPING". International Journal of Structural Stability and Dynamics 13, nr 02 (marzec 2013): 1350018. http://dx.doi.org/10.1142/s0219455413500181.

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This paper is concerned with the nonlinear damped vibration of prestressed orthotropic membrane structures. The Krylov–Bogolubov–Mitropolsky (KBM) perturbation method is employed for solving the governing equations of large amplitude nonlinear vibration of rectangular orthotropic membranes with viscous damping. Presented herein are asymptotic analytical solutions for the frequency and displacement function of large amplitude nonlinear damped vibration of rectangular orthotropic membranes with four edges simply supported or fixed. Through the computational example, we compared and analyzed the frequency results. Meanwhile, the vibration mode of the membrane and the displacement and time curve of each feature point on the membrane surface were analyzed. The results obtained herein provide a simple and convenient approach to calculate the frequency and lateral displacement of large amplitude nonlinear vibration of rectangular orthotropic membranes with low viscous damping. In addition, the results provide some computational basis for the vibration control and dynamic design of membrane structures.

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Chavent, Matthieu, Tyler Reddy, Joseph Goose, Anna Caroline E. Dahl, John E. Stone, Bruno Jobard i Mark S. P. Sansom. "Methodologies for the analysis of instantaneous lipid diffusion in md simulations of large membrane systems". Faraday Discuss. 169 (2014): 455–75. http://dx.doi.org/10.1039/c3fd00145h.

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Interactions between lipids and membrane proteins play a key role in determining the nanoscale dynamic and structural properties of biological membranes. Molecular dynamics (MD) simulations provide a valuable tool for studying membrane models, complementing experimental approaches. It is now possible to simulate large membrane systems, such as simplified models of bacterial and viral envelope membranes. Consequently, there is a pressing need to develop tools to visualize and quantify the dynamics of these immense systems, which typically comprise millions of particles. To tackle this issue, we have developed visual and quantitative analyses of molecular positions and their velocity field using path line, vector field and streamline techniques. This allows us to highlight large, transient flow-like movements of lipids and to better understand crowding within the lipid bilayer. The current study focuses on visualization and analysis of lipid dynamics. However, the methods are flexible and can be readily applied to e.g. proteins and nanoparticles within large complex membranes. The protocols developed here are readily accessible both as a plugin for the molecular visualization program VMD and as a module for the MDAnalysis library.

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Wang, Xiaofeng, Haoyue Chu i Qingshan Yang. "Numerical analysis of dynamic properties of wrinkled thin membranes". Engineering Computations 37, nr 8 (8.04.2020): 2871–94. http://dx.doi.org/10.1108/ec-10-2018-0459.

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Purpose This paper aims to numerically study the effects of boundary conditions, pre-stress, material constants and thickness on the dynamic performance of a wrinkled thin membrane. Design/methodology/approach Based on the stability theory of plates and shells, the dynamic equations of a wrinkled thin membrane were developed, and they were solved with the Lanczos method Findings The effects of wrinkle-influencing factors on the dynamic performance of a wrinkled membrane are determined by the wrinkling stage. The effects are prominent when wrinkling deformation is evolving, but they are very small and can hardly be observed when wrinkling deformation is stable. Mode shapes of a wrinkled membrane are sensitive to boundary conditions, pre-stress and Poisson’s ratio, but its natural frequencies are sensitive to all these five factors. Practical implications The research work in this paper is expected to help understand the dynamic behavior of a wrinkled membrane and present access to ensuring its dynamic stability by controlling the wrinkle-influencing factors. Originality/value Very few documents investigated the dynamic properties of wrinkled membranes. No attention has yet been paid by the present literature to the global dynamic performance of a wrinkled membrane under the influences of the factors that play a pivotal role in the wrinkling deformation. In view of this, this paper numerically studied the global modes and corresponding frequencies of a wrinkled membrane and their variation with the wrinkle-influencing factors. The results indicate that the global dynamic properties of a wrinkled membrane are sensitive to these factors at the stage of wrinkling evolution.

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Greaves, Jennifer, Juliet A. Carmichael i Luke H. Chamberlain. "The palmitoyl transferase DHHC2 targets a dynamic membrane cycling pathway: regulation by a C-terminal domain". Molecular Biology of the Cell 22, nr 11 (czerwiec 2011): 1887–95. http://dx.doi.org/10.1091/mbc.e10-11-0924.

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Intracellular palmitoylation dynamics are regulated by a large family of DHHC (Asp-His-His-Cys) palmitoyl transferases. The majority of DHHC proteins associate with endoplasmic reticulum (ER) or Golgi membranes, but an interesting exception is DHHC2, which localizes to dendritic vesicles of unknown origin in neurons, where it regulates dynamic palmitoylation of PSD95. Dendritic targeting of newly synthesized PSD95 is likely preceded by palmitoylation on Golgi membranes by DHHC3 and/or DHHC15. The precise intracellular distribution of DHHC2 is presently unclear, and there is very little known in general about how DHHC proteins achieve their respective localizations. In this study, membrane targeting of DHHC2 in live and fixed neuroendocrine cells was investigated and mutational analysis employed to define regions of DHHC2 that regulate targeting. We report that DHHC2 associates with the plasma membrane, Rab11-positive recycling endosomes, and vesicular structures. Plasma membrane integration of DHHC2 was confirmed by labeling of an extrafacial HA epitope in nonpermeabilized cells. Antibody-uptake experiments suggested that DHHC2 traffics between the plasma membrane and intracellular membranes. This dynamic localization was confirmed using fluorescence recovery after photo-bleaching analysis, which revealed constitutive refilling of the recycling endosome (RE) pool of DHHC2. The cytoplasmic C-terminus of DHHC2 regulates membrane targeting and a mutant lacking this domain was associated with the ER. Although DHHC2 is closely related to DHHC15, these proteins populate distinct membrane compartments. Construction of chimeric DHHC2/DHHC15 proteins revealed that this difference in localization is a consequence of divergent sequences within their C-terminal tails. This study is the first to highlight dynamic cycling of a mammalian DHHC protein between clearly defined membrane compartments, and to identify domains that specify membrane targeting of this protein family.

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Liu, Yan, George Chen, Xiuli Yang i Huining Deng. "Preparation of Layer-by-Layer Nanofiltration Membranes by Dynamic Deposition and Crosslinking". Membranes 9, nr 2 (24.01.2019): 20. http://dx.doi.org/10.3390/membranes9020020.

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In recent decades, the advancements in layer-by-layer (LBL) assembly technology have provoked increasing interest in the preparation of multilayer polyelectrolyte membranes with excellent performance. In the current study, a novel nanofiltration (NF) membrane was prepared by pressure-driven layer-by-layer (LBL) assembly of polyethylenimine (PEI) and polyacrylicacid (PAA) on a porous substrate with chemical crosslinking. The effect of deposition pressure on separation performance of the prepared membranes was studied. The surface morphology, hydrophilicity and the charge property of the dynamically-deposited membranes were compared with those prepared by static adsorption. The characterization results showed that dynamic deposition process resulted in a smoother membrane surface with improved hydrophilicity. The mechanism of water-path formation was proposed to interpret the effect of pressure on the membrane performance. Glutaraldehyde (GA) was used as a crosslinker to reduce the number of polyelectrolyte bilayers for obtaining good separation performance. The rejections of different inorganic salts of the dynamically-deposited NF membrane were also investigated.

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He, Bin, Xiaomeng Yu, Moran Margolis, Xianghua Liu, Xiaohong Leng, Yael Etzion, Fei Zheng i in. "Live-Cell Imaging in Caenorhabditis elegans Reveals the Distinct Roles of Dynamin Self-Assembly and Guanosine Triphosphate Hydrolysis in the Removal of Apoptotic Cells". Molecular Biology of the Cell 21, nr 4 (15.02.2010): 610–29. http://dx.doi.org/10.1091/mbc.e09-05-0440.

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Dynamins are large GTPases that oligomerize along membranes. Dynamin's membrane fission activity is believed to underlie many of its physiological functions in membrane trafficking. Previously, we reported that DYN-1 ( Caenorhabditis elegans dynamin) drove the engulfment and degradation of apoptotic cells through promoting the recruitment and fusion of intracellular vesicles to phagocytic cups and phagosomes, an activity distinct from dynamin's well-known membrane fission activity. Here, we have detected the oligomerization of DYN-1 in living C. elegans embryos and identified DYN-1 mutations that abolish DYN-1's oligomerization or GTPase activities. Specifically, abolishing self-assembly destroys DYN-1's association with the surfaces of extending pseudopods and maturing phagosomes, whereas inactivating guanosine triphosphate (GTP) binding blocks the dissociation of DYN-1 from these membranes. Abolishing the self-assembly or GTPase activities of DYN-1 leads to common as well as differential phagosomal maturation defects. Whereas both types of mutations cause delays in the transient enrichment of the RAB-5 GTPase to phagosomal surfaces, only the self-assembly mutation but not GTP binding mutation causes failure in recruiting the RAB-7 GTPase to phagosomal surfaces. We propose that during cell corpse removal, dynamin's self-assembly and GTP hydrolysis activities establish a precise dynamic control of DYN-1's transient association to its target membranes and that this control mechanism underlies the dynamic recruitment of downstream effectors to target membranes.

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Ma, Yuanqing, Elizabeth Hinde i Katharina Gaus. "Nanodomains in biological membranes". Essays in Biochemistry 57 (6.02.2015): 93–107. http://dx.doi.org/10.1042/bse0570093.

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Lipid rafts are defined as cholesterol- and sphingomyelin-enriched membrane domains in the plasma membrane of cells that are highly dynamic and cannot be resolved with conventional light microscopy. Membrane proteins that are embedded in the phospholipid matrix can be grouped into raft and non-raft proteins based on their association with detergent-resistant membranes in biochemical assays. Selective lipid–protein interactions not only produce heterogeneity in the membrane, but also cause the spatial compartmentalization of membrane reactions. It has been proposed that lipid rafts function as platforms during cell signalling transduction processes such as T-cell activation (see Chapter 13 (pages 165–175)). It has been proposed that raft association co-localizes specific signalling proteins that may yield the formation of the observed signalling microclusters at the immunological synapses. However, because of the nanometre size and high dynamics of lipid rafts, direct observations have been technically challenging, leading to an ongoing discussion of the lipid raft model and its alternatives. Recent developments in fluorescence imaging techniques have provided new opportunities to investigate the organization of cell membranes with unprecedented spatial resolution. In this chapter, we describe the concept of the lipid raft and alternative models and how new imaging technologies have advanced these concepts.

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Santo, Loredana, Fabrizio Quadrini, Denise Bellisario, Antonella Polimeni i Anna Santarsiero. "Variability of Mechanical Properties of Collagen Membranes used in Dentistry". Materiale Plastice 55, nr 4 (30.12.2018): 488–93. http://dx.doi.org/10.37358/mp.18.4.5059.

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The aim of this study is proposing a combination of measurements to assess the functional variability of collagen membranes used in Guided Bone Regeneration (GBR) and Guided Tissue Regeneration (GTR) techniques. As far as clinical applications are concerned, a proper qualification is critical when deciding, among commercially available collagen membranes, upon the most appropriate one for each specific clinical case. Two commercially available collagen membranes, namely Collprotect� and Jason�, were considered for the experimentation. After thickness and density measurements, the quasi-static behavior was studied for both membranes by means of conventional mechanical tests, i.e. tear and tensile tests, whereas their time-dependent behavior was evaluated by means of stress relaxation tests and dynamic mechanical analysis. Collagen membranes showed an elevated among samples variability. The variability within the same kind of membrane is of the same order of magnitude of the between membrane kinds variability. All the membranes showed strong time dependence both in stress relaxation and in dynamic mechanical tests. This fact should be taken under consideration for the membrane final application.

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OHTANI, Toshio, Atsuo WATANABE i Shoji KIMURA. "The characteristics and applications of dynamic and inorganic membranes." membrane 13, nr 6 (1988): 321–34. http://dx.doi.org/10.5360/membrane.13.321.

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Chen, Charles H., Jakob P. Ulmschneider i Martin B. Ulmschneider. "Mechanisms of a Small Membrane-Active Antimicrobial Peptide from Hyla punctata". Australian Journal of Chemistry 73, nr 3 (2020): 236. http://dx.doi.org/10.1071/ch19429.

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Thousands of antimicrobial peptides have been observed and studied in the past decades; however, their membrane-active mechanisms are ambiguous due to their dynamic structure in the cell membrane. Here, we applied both molecular dynamics (MD) simulations and biophysical experiments to study the small membrane-active antimicrobial peptide Hylaseptin P1 (HSP1), which has significant selectivity towards anionic 1-palmitoyl-2-oleoyl-sn-glycero-3-phospho-(1′-rac-glycerol) (POPG) and bacterial model membranes. HSP1 does not bind and fold onto human red blood cell model membranes, and it only binds, but does not fold, in zwitterionic 1-palmitoyl-2-oleoyl-glycero-3-phosphocholine (POPC) membranes. This suggests that the lipid chemistry and membrane rigidity are key to prevent HSP1 binding onto membranes, and the lipid headgroup charge may further promote peptide folding in the membrane. Our experiment-validated MD simulations suggest a carpet-like model mechanism for HSP1 through peptide binding, folding, aggregation, and assembly. HSP1 is shorter than the membrane thickness; therefore, the folded peptides aggregate on the surface, cross the membrane, and the oligomeric structure is supported by several surface-bound peptides in both bilayer leaflets.

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Cazacu, Adinela, Mathieu Micahud, Rémi Caraballo, Carol Arnal-Herault, Andreaa Pasc-Banu, André ayral i Mihail Barboiu. "Dynamic supramolecular hybrid and mesoporous membranes". Annales de Chimie Science des Matériaux 32, nr 2 (18.04.2007): 127–40. http://dx.doi.org/10.3166/acsm.32.127-140.

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Shindell, Orrin, Natalie Mica, Kwan H. Cheng, Exing Wang i Vernita D. Gordon. "Dynamic Fingering in Adhered Lipid Membranes". Langmuir 34, nr 15 (24.01.2018): 4673–80. http://dx.doi.org/10.1021/acs.langmuir.7b03708.

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Verron, E., R. E. Khayat, A. Derdouri i B. Peseux. "Dynamic inflation of hyperelastic spherical membranes". Journal of Rheology 43, nr 5 (wrzesień 1999): 1083–97. http://dx.doi.org/10.1122/1.551017.

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Camley, Brian A. "Emergent Shape Sensing of Dynamic Membranes". Biophysical Journal 116, nr 3 (luty 2019): 216a—217a. http://dx.doi.org/10.1016/j.bpj.2018.11.1195.

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Suetsugu, Shiro, Shusaku Kurisu i Tadaomi Takenawa. "Dynamic Shaping of Cellular Membranes by Phospholipids and Membrane-Deforming Proteins". Physiological Reviews 94, nr 4 (październik 2014): 1219–48. http://dx.doi.org/10.1152/physrev.00040.2013.

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All cellular compartments are separated from the external environment by a membrane, which consists of a lipid bilayer. Subcellular structures, including clathrin-coated pits, caveolae, filopodia, lamellipodia, podosomes, and other intracellular membrane systems, are molded into their specific submicron-scale shapes through various mechanisms. Cells construct their micro-structures on plasma membrane and execute vital functions for life, such as cell migration, cell division, endocytosis, exocytosis, and cytoskeletal regulation. The plasma membrane, rich in anionic phospholipids, utilizes the electrostatic nature of the lipids, specifically the phosphoinositides, to form interactions with cytosolic proteins. These cytosolic proteins have three modes of interaction: 1) electrostatic interaction through unstructured polycationic regions, 2) through structured phosphoinositide-specific binding domains, and 3) through structured domains that bind the membrane without specificity for particular phospholipid. Among the structured domains, there are several that have membrane-deforming activity, which is essential for the formation of concave or convex membrane curvature. These domains include the amphipathic helix, which deforms the membrane by hemi-insertion of the helix with both hydrophobic and electrostatic interactions, and/or the BAR domain superfamily, known to use their positively charged, curved structural surface to deform membranes. Below the membrane, actin filaments support the micro-structures through interactions with several BAR proteins as well as other scaffold proteins, resulting in outward and inward membrane micro-structure formation. Here, we describe the characteristics of phospholipids, and the mechanisms utilized by phosphoinositides to regulate cellular events. We then summarize the precise mechanisms underlying the construction of membrane micro-structures and their involvements in physiological and pathological processes.

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38

Raghunathan, Krishnan, i Anne K. Kenworthy. "Dynamic pattern generation in cell membranes: Current insights into membrane organization". Biochimica et Biophysica Acta (BBA) - Biomembranes 1860, nr 10 (październik 2018): 2018–31. http://dx.doi.org/10.1016/j.bbamem.2018.05.002.

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Gillighan, A., S. J. Judd i R. Eyres. "Membrane thickening of water works sludge". Water Supply 1, nr 5-6 (1.06.2001): 215–20. http://dx.doi.org/10.2166/ws.2001.0117.

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The efficacy of ultrafiltration (UF) and microfiltration (MF) membranes was assessed for the concentration of actual waterworks sludges using crossflow tubular membranes operated at constant trans-membrane pressure. The MF membrane gave higher initial fluxes than the UF membrane but after 10 min of filtration the flux value and its decline tended to be very similar for both membranes operating under the same conditions. All membranes gave permeate product water of <0.2 NTU and <100ppb coagulant at all times. For both membranes mechanical cleaning, with sponge balls, was at least as effective as acid chemical cleaning, indicating that no significant permanent internal fouling occurred for these membrane materials. Hydraulic resistance data indicated a significant difference in the dynamic layer resistance between the two membranes. Whilst the UF membrane had a hydraulic resistance 3.7 times that of the MF membrane, the dynamic layer formed on the UF membrane during operation displayed a maximum hydraulic resistance almost nine times lower than that of the MF membrane operating under the same conditions. Correlation of cake resistance R versus feed solids concentration C for all the data generated for t>0 demonstrated reasonable agreement with the expression R∝ca where a=0.37 in the current study. This trend has been recorded in previous reported studies, a varying between 0.33 and 0.62 depending on sludge dewaterability.

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Mullineaux, Conrad W. "The thylakoid membranes of cyanobacteria: structure, dynamics and function". Functional Plant Biology 26, nr 7 (1999): 671. http://dx.doi.org/10.1071/pp99027.

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In recent years there has been remarkable progress in determining the three-dimensional structures of photosynthetic complexes. A new challenge is emerging: can we understand the organisation and interaction of those complexes in the intact photosynthetic membrane? Intact membranes are complex, dynamic systems. If we are to understand the function of the intact membrane, we will need to understand the organisation of the complexes, how they can diffuse and interact in the membrane, how they are assembled, repaired and broken down, and how their function is regulated. Cyanobacteria have some crucial advantages as model systems. The complete sequencing of the Synechocystis 6803 genome, coupled with the ease of genetic manipulation of Synechocystis (and certain other cyanobacteria) have given us a unique tool for studying a photosynthetic organism. Furthermore, some cyanobacteria have a very simple, regular thylakoid membrane structure. The unique geometry of photosynthetic membranes of these cyanobacteria will greatly facilitate biophysical studies of membrane function. This review summarises recent progress in understanding the structure, function and dynamics of cyanobacterial thylakoid membranes, highlights the questions that remain to be answered and suggests some possible approaches towards solving those questions.

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Gryta, Marek, Justyna Bastrzyk i Diana Lech. "Evaluation of fouling potential of nanofiltration membranes based on the dynamic contact angle measurements". Polish Journal of Chemical Technology 14, nr 3 (1.10.2012): 97–104. http://dx.doi.org/10.2478/v10026-012-0091-4.

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In this work the studies were performed on the intensity of fouling of the membrane NF90 and NF270 depending on the value of dynamic contact angle, previously determined for these membrane. The NF membranes were used for the separation of broth obtained during the fermentation of glycerol by Lactobacilluscasei bacteria. The measurements of dynamic contact angle were carried out using the Wilhelmy plate method. Taped membranes samples (support layer to support layer), wetted for 2 days in deionized water prior to testing, were used to study the contact angle of top layer and its organic fouling. Using deionized water; the contact angle values equal to 27-30o and 53-57o for NF270 and NF90, respectively, were obtained. As a consequence of adsorption of organic compound on the membrane surfaces, the contact angle obtained for both fouled membranes was about 55-56o, and this value was closer to the contact angle of non-fouled NF90 membrane. Therefore, the NF90 membrane was more resistant to organic fouling during the separation of broth.

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Wang, Meina, Adriana M. Mihut, Ellen Rieloff, Aleksandra P. Dabkowska, Linda K. Månsson, Jasper N. Immink, Emma Sparr i Jérôme J. Crassous. "Assembling responsive microgels at responsive lipid membranes". Proceedings of the National Academy of Sciences 116, nr 12 (1.03.2019): 5442–50. http://dx.doi.org/10.1073/pnas.1807790116.

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Directed colloidal self-assembly at fluid interfaces can have a large impact in the fields of nanotechnology, materials, and biomedical sciences. The ability to control interfacial self-assembly relies on the fine interplay between bulk and surface interactions. Here, we investigate the interfacial assembly of thermoresponsive microgels and lipogels at the surface of giant unilamellar vesicles (GUVs) consisting of phospholipids bilayers with different compositions. By altering the properties of the lipid membrane and the microgel particles, it is possible to control the adsorption/desorption processes as well as the organization and dynamics of the colloids at the vesicle surface. No translocation of the microgels and lipogels through the membrane was observed for any of the membrane compositions and temperatures investigated. The lipid membranes with fluid chains provide highly dynamic interfaces that can host and mediate long-range ordering into 2D hexagonal crystals. This is in clear contrast to the conditions when the membranes are composed of lipids with solid chains, where there is no crystalline arrangement, and most of the particles desorb from the membrane. Likewise, we show that in segregated membranes, the soft microgel colloids form closely packed 2D crystals on the fluid bilayer domains, while hardly any particles adhere to the more solid bilayer domains. These findings thus present an approach for selective and controlled colloidal assembly at lipid membranes, opening routes toward the development of tunable soft materials.

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Anand, Ruchika, Andreas S. Reichert i Arun Kumar Kondadi. "Emerging Roles of the MICOS Complex in Cristae Dynamics and Biogenesis". Biology 10, nr 7 (29.06.2021): 600. http://dx.doi.org/10.3390/biology10070600.

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Mitochondria are double membrane-enclosed organelles performing important cellular and metabolic functions such as ATP generation, heme biogenesis, apoptosis, ROS production and calcium buffering. The mitochondrial inner membrane (IM) is folded into cristae membranes (CMs) of variable shapes using molecular players including the ‘mitochondrial contact site and cristae organizing system’ (MICOS) complex, the dynamin-like GTPase OPA1, the F1FO ATP synthase and cardiolipin. Aberrant cristae structures are associated with different disorders such as diabetes, neurodegeneration, cancer and hepato-encephalopathy. In this review, we provide an updated view on cristae biogenesis by focusing on novel roles of the MICOS complex in cristae dynamics and shaping of cristae. For over seven decades, cristae were considered as static structures. It was recently shown that cristae constantly undergo rapid dynamic remodeling events. Several studies have re-oriented our perception on the dynamic internal ambience of mitochondrial compartments. In addition, we discuss the recent literature which sheds light on the still poorly understood aspect of cristae biogenesis, focusing on the role of MICOS and its subunits. Overall, we provide an integrated and updated view on the relation between the biogenesis of cristae and the novel aspect of cristae dynamics.

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Ader, C., R. Schneider, K. Seidel, M. Etzkorn i M. Baldus. "Magic-angle-spinning NMR spectroscopy applied to small molecules and peptides in lipid bilayers". Biochemical Society Transactions 35, nr 5 (25.10.2007): 991–95. http://dx.doi.org/10.1042/bst0350991.

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ssNMR (solid-state NMR) spectroscopy provides increasing possibilities to study the structural and dynamic aspects of biological membranes. Here, we review recent ssNMR experiments that are based on MAS (magic angle spinning) and that provide insight into the structure and dynamics of membrane systems at the atomic level. Such methods can be used to study membrane architecture, domain formation or molecular complexation in a way that is highly complementary to other biophysical methods such as imaging or calorimetry.

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45

Kim, Chun Il, i Zhe Liu. "Mechanics of Lipid Membranes under the Influence of Intramembrane Viscosity". Mathematical Problems in Engineering 2019 (7.04.2019): 1–13. http://dx.doi.org/10.1155/2019/3412129.

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We discuss a continuum-based model describing the deformations of lipid membranes subjected to intramembrane viscosity. Within the frame work of the theory of an elastic surface, the membrane equilibrium equations and the expressions of viscous stress are obtained. The corresponding deformation energy of the membrane is computed via the first and second fundamental form of surface. A compatible linear model is also formulated within the prescription of superposed incremental deformations through which the deformation profiles of the membrane is obtained. It is shown that the intramembrane viscous flow gives rise to straining effects on the membranes. Further, the corresponding dynamic edge conditions reduce to purely elastic boundary conditions in the limit of vanishing viscous effects. Lastly, admissible sets of velocity fields are also examined and are used to formulate membrane shape equations and the associated dynamic boundary conditions.

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Chen, Shu-Ting, S. Ranil Wickramasinghe i Xianghong Qian. "Electrospun Weak Anion-Exchange Fibrous Membranes for Protein Purification". Membranes 10, nr 3 (1.03.2020): 39. http://dx.doi.org/10.3390/membranes10030039.

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Membrane based ion-exchange (IEX) and hydrophobic interaction chromatography (HIC) for protein purification is often used to remove impurities and aggregates operated under the flow-through mode. IEX and HIC are also limited by capacity and recovery when operated under bind-and-elute mode for the fractionation of proteins. Electrospun nanofibrous membrane is characterized by its high surface area to volume ratio and high permeability. Here tertiary amine ligands are grafted onto the electrospun polysulfone (PSf) and polyacrylonitrile (PAN) membrane substrates using UV-initiated polymerization. Static and dynamic binding capacities for model protein bovine serum albumin (BSA) were determined under appropriate bind and elute buffer conditions. Static and dynamic binding capacities in the order of ~100 mg/mL were obtained for the functionalized electrospun PAN membranes whereas these values reached ~200 mg/mL for the functionalized electrospun PSf membranes. Protein recovery of over 96% was obtained for PAN-based membranes. However, it is only 56% for PSf-based membranes. Our work indicates that surface modification of electrospun membranes by grafting polymeric ligands can enhance protein adsorption due to increased surface area-to-volume ratio.

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Xue, Jie, Xiyu Liu, Wenxing Sun i Shuo Yan. "Discrete Morse Theory Based Dynamic P Systems". Journal of Advanced Computational Intelligence and Intelligent Informatics 22, nr 1 (20.01.2018): 104–12. http://dx.doi.org/10.20965/jaciii.2018.p0104.

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This paper proposes a class of dynamic P systems with constraint of discrete Morse function (DMDP systems). Membrane structure is extended on complex. Rules control activities of membranes. New classes of rules and mechanism to change types of rules by discrete gradient vector field are provided as well.DMDP system extends P systems both in structures and rules. Solving air quality evaluation problem in linear time verifies the effectiveness ofDMDP systems. Since air quality evaluation problem has significance in many areas. The new P systems provide an alternative for traditional membrane computing.

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Fazullin, D. D., G. V. Mavrin i L. I. Fazullina. "Separation of Oil Emulsion with Dynamic Membrane with Surface Layer of Polystyrene". Oil and Gas Technologies 132, nr 1 (2021): 10–14. http://dx.doi.org/10.32935/1815-2600-2021-132-1-10-14.

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In this paper, we studied the parameters of the process of separation of oil emulsion using a dynamic membrane of ultrafiltration PTFEg-PSd. A polymer membrane with a dynamic layer of polystyrene particles with sizes from 55 to 72 nm was obtained on a substrate of hydrophilic polytetrafluoroethylene (PTFE). The results of scanning electron microscopy showed the formation of a layer of spherical polystyrene particles on the membrane surface. The properties of a dynamic membrane were studied: porosity, moisture capacity, and wettability. After applying the polystyrene layer, an increase in the hydrophobicity of the surface layer of the membrane was established. For membrane separation, a 1% oil emulsion was prepared by dispersing the carbonaceous oil. The retention capacity of membranes for oil products from 1% oil emulsion was 96.4%, with a specific productivity of 113 dm3/m2·h which is not inferior to the performance of a commercial UPM-100 ultrafiltration membrane. Particle sizes of the dispersed phase in a 1% oil emulsion are distributed in the range from 229 to 1476 nm, after separation of the emulsion by a dynamic membrane, oil particles with sizes from 134 to 236 nm were detected in the filtrate, which indicates the removal of the bulk of the dispersed phase from the emulsion by ultrafiltration membranes.

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Skene, J. H., i I. Virág. "Posttranslational membrane attachment and dynamic fatty acylation of a neuronal growth cone protein, GAP-43." Journal of Cell Biology 108, nr 2 (1.02.1989): 613–24. http://dx.doi.org/10.1083/jcb.108.2.613.

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Growth cones, the motile apparatus at the ends of elongating axons, are sites of extensive and dynamic membrane-cytoskeletal interaction and insertion of new membrane into the growing axon. One of the most abundant proteins in growth cone membranes is a protein designated GAP-43, whose synthesis increases dramatically in most neurons during periods of axon development or regeneration. We have begun to explore the role of GAP-43 in growth cone membrane functions by asking how the protein interacts with those membranes. Membrane-washing experiments indicate that mature GAP-43 is tightly bound to growth cone membranes, and partitioning of Triton X-114-solubilized GAP-43 between detergent-enriched and detergent-depleted phases indicates considerable hydrophobicity. The hydrophobic behavior of the protein is modulated by divalent cations, particularly zinc and calcium. In vivo labeling of GAP-43 in neonatal rat brain with [35S]methionine shows that GAP-43 is initially synthesized as a soluble protein that becomes attached to membranes posttranslationally. In tissue culture, both rat cerebral cortex cells and neuron-like PC12 cells actively incorporate [3H]palmitic acid into GAP-43. Isolated growth cones detached from their cell bodies also incorporate labeled fatty acid into GAP-43, suggesting active turnover of the fatty acid moieties on the mature protein. Hydrolysis of ester-like bonds with neutral hydroxylamine removes the bound fatty acid and exposes new thiol groups on GAP-43, suggesting that fatty acid is attached to the protein's only two cysteine residues, located in a short hydrophobic domain at the amino terminus. Modulation of the protein's hydrophobic behavior by divalent cations suggests that other domains, containing large numbers of negatively charged residues, might also contribute to GAP-43-membrane interactions. Our observations suggest a dynamic and reversible interaction of GAP-43 with growth cone membranes.

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Xing You, Hong, Xiaoyang Qi i Lei Yu. "Real-Time Observation of Phospholipid Bilayer Membrane Restructuring Induced by Protein Molecules using Atomic Force Microscopy". Microscopy and Microanalysis 7, S2 (sierpień 2001): 858–59. http://dx.doi.org/10.1017/s1431927600030361.

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Atomic force microscopy (AFM) allows the surfaces of native biological materials to be imaged in aqueous solution with submolecular resolution. The ability to perform AFM imaging in aqueous and physiological environment has made it possible to monitor important biological processes in real time at high resolution. Currently, there is a great deal of interest in AFM studies of the structure and property of lipid bilayer membranes and protein interactions with lipid bilayer membranes. Lipid bilayer membranes in biological cells form a permeability barrier, which controls the flow of ions, water, and other molecules between biological cells and their environments, whereas membrane-bound and/or membrane-associated proteins are responsible for most of the dynamic functions carried out by the membrane. However, real-time AFM monitoring of dynamic biological processes has been challenged by the limited temporal resolution of AFM, potential physical damage to soft biological samples, and intrinsic complexity of biological processes. There are few successful examples of AFM real-time studies of dynamic biological events, particularly in the aspect of protein interactions with lipid bilayer membranes.We have attempted to use atomic force microscopy to study interactions between a particular protein, saposin C, and phospholipid bilayer membranes in real time. Saposin C (Sap C), a small glycoprotein, is an essential co-factor for the hydrolysis of glucosylceramide by glucosylceramidase in lysosomes, and a deficiency of Sap C leads to a variant form of Gauchers’ diseases. Supported planar phospholipid bilayer membranes were used in the study.

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