Abstract:
:In this paper, we consider the effect of adding small carbohydrate solutes (small sugars) to DMPC (1,2-dimyristoyl-sn-glycero-3-phosphocholine) L(alpha) dispersions and the consequences on the force balance at zero osmotic pressure (maximal swelling). We show the importance of long incubations required to obtain samples at thermodynamic equilibrium where molecular diffusion has been completed. The monotonic increase of maximal swelling versus sugar content occurs as a combined effect of the screening of the van der Waals contribution and fluctuations in the lamellar stacks. According to this new approach, it is shown that changes in dielectric properties result in a much less pronounced effect than entropic forces (undulations) generated by the softening of the membranes at high sugar content. However, this sugar-induced swelling cannot be explained quantitatively by adding an entropic contribution to molecular interactions. Quantitative disagreement between the proposed mechanism and our observations is due either to nonadditivity of molecular interactions with entropic forces or to the relation used to account for the entropic contribution.
journal_name
Biophys Jjournal_title
Biophysical journalauthors
Demé B,Dubois M,Zemb Tdoi
10.1016/S0006-3495(02)75388-5subject
Has Abstractpub_date
2002-01-01 00:00:00pages
215-25issue
1 Pt 1eissn
0006-3495issn
1542-0086pii
S0006-3495(02)75388-5journal_volume
82pub_type
杂志文章abstract::Single molecule force spectroscopy methods, such as optical and magnetic tweezers and atomic force microscopy, have opened up the possibility to study biological processes regulated by force, dynamics of structural conformations of proteins and nucleic acids, and load-dependent kinetics of molecular interactions. Amon...
journal_title:Biophysical journal
pub_type: 杂志文章,评审
doi:10.1016/j.bpj.2013.08.007
更新日期:2013-09-17 00:00:00
abstract::The heterologous expression and purification of membrane proteins represent major limitations for their functional and structural analysis. Here we describe a new method of incorporation of transmembrane proteins in planar lipid bilayer starting from 1 pmol of solubilized proteins. The principle relies on the direct i...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1529/biophysj.106.087791
更新日期:2006-11-01 00:00:00
abstract::Evidence that the fluorophore sempervirene binds to nucleic acids is presented. The complexes were studied by fluorescence intensity, spectra, decay lifetime, and polarization methods. Both fluorescent and nonfluorescent complexes are formed. The sempervirene is rigidly fixed to DNA. If ethidium bromide and sempervire...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/s0006-3495(74)85906-0
更新日期:1974-03-01 00:00:00
abstract::Clathrin-coated membranes are precursors to coated vesicles in the receptor-mediated endocytic pathway. In this paper we present a physical model for the first steps of the transformation of a clathrin-coated membrane into a coated vesicle. The theory is based on in vitro cytoplasmic acidification experiments of Heuse...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(98)77993-7
更新日期:1998-06-01 00:00:00
abstract::In this study, we used microbeam grazing-incidence small-angle x-ray scattering (muGISAXS) to investigate in situ protein nucleation and crystal growth assisted by a protein nanotemplate, and introduced certain innovations to improve the method. Our aim was to understand the protein nanotemplate method in detail, as t...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2010.03.069
更新日期:2010-08-09 00:00:00
abstract::Many organisms are able to survive subzero temperatures at which bodily fluids would normally be expected to freeze. These organisms have adapted to these lower temperatures by synthesizing antifreeze proteins (AFPs), capable of binding to ice, which make further growth of ice energetically unfavorable. To date, the s...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(01)75821-3
更新日期:2001-09-01 00:00:00
abstract::Low frequency audible vibrations are produced by human skeletal muscles undergoing sustained contraction. The effect is easily demonstrable with an electronic stethoscope which amplifies sound below 50 Hz. Autocorrelation analysis of the signal shows that it is periodic with a frequency 25 +/- 2.5 Hz. The quality of t...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(80)85080-6
更新日期:1980-04-01 00:00:00
abstract::Back-of-the-envelope or rule-of-thumb calculations involving rough estimates of quantities play a central scientific role in developing intuition about the structure and behavior of physical systems, for example in so-called Fermi problems in the physical sciences. Such calculations can be used to powerfully and quant...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2014.08.040
更新日期:2014-12-02 00:00:00
abstract::Recent studies suggest that phosphoinositide kinases may participate in intracellular trafficking or exocytotic events. Because both of these events ultimately require fusion of biological membranes, the susceptibility of membranes containing polyphosphoinositides (PPIs) to divalent cation-induced fusion was investiga...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(96)79513-9
更新日期:1996-12-01 00:00:00
abstract::Von Willebrand factor (VWF) is a multimeric plasma glycoprotein involved in both hemostasis and thrombosis. VWF conformational changes, especially unfolding of the A2 domain, may be required for efficient enzymatic cleavage in vivo. It has been shown that a single A2 domain unfolds at most probable unfolding forces of...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2009.12.4324
更新日期:2010-04-21 00:00:00
abstract::Segmentation of the Drosophila melanogaster embryo results from the dynamic establishment of spatial mRNA and protein patterns. Here, we exploit recent temporal mRNA and protein expression measurements on the full surface of the blastoderm to calibrate a dynamical model of the gap gene network on the entire embryo cor...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2011.05.060
更新日期:2011-07-20 00:00:00
abstract::Odorant-induced currents in mammalian olfactory receptor neurons have proved difficult to obtain reliably using conventional whole-cell recording. By using a mathematical model of the electrical circuit of the patch and rest-of-cell, we demonstrate how cell-attached patch measurements can be used to quantitatively ana...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(97)78791-5
更新日期:1997-03-01 00:00:00
abstract::We report evidence for an unconventional type of allosteric regulation of a biomotor. We show that the genome-packaging motor of phage ϕ29 is regulated by a sensor that detects the density and conformation of the DNA packaged inside the viral capsid, and slows the motor by a mechanism distinct from the effect of a dir...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2014.11.3469
更新日期:2015-01-20 00:00:00
abstract::The pKa values of ionizable groups that lie between the active site region of bacteriorhodopsin (bR) and the extracellular surface of the protein are reported. Glu-204 is found to have an elevated pKa in the resting state of bR, suggesting that it corresponds to the proton-releasing group in bR. Its elevated pKa is pr...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(96)79320-7
更新日期:1996-09-01 00:00:00
abstract::Recent experimental studies of the role of microtubule sliding in neurite outgrowth suggested a qualitative model, according to which kinesin-1 motors push the minus-end-out microtubules against the cell membrane and generate the early cell processes. At the later stage, dynein takes over the sliding, expels the minus...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2018.08.046
更新日期:2018-10-16 00:00:00
abstract::We present higher-order moment analysis of fluorescence intensity fluctuations from individual laser scanning microscopy images applied to study monomer-oligomer distributions. We demonstrate that the number densities and brightness ratios of a mixed population of monomers and oligomers can be determined by analyzing ...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1529/biophysj.106.091181
更新日期:2006-11-15 00:00:00
abstract::Skeletal muscle contraction is a canonical example of motor-driven force generation. Despite the long history of research in this topic, a mechanistic explanation of the collective myosin force generation is lacking. We present a theoretical model of muscle contraction based on the conformational movements of individu...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1529/biophysj.104.056846
更新日期:2005-06-01 00:00:00
abstract::Ca2+ entry under resting conditions may be important for contraction of vascular smooth muscle, but little is known about the mechanisms involved. Ca2+ leakage was studied in the A7r5 smooth muscle-derived cell line by patch-clamp techniques. Two channels that could mediate calcium influx at resting membrane potential...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(98)74047-0
更新日期:1998-09-01 00:00:00
abstract::A complete mechanistic understanding of membrane-localized processes in vesicular transport, such as membrane budding and fission, requires their reconstitution with biochemically-defined components from a biochemically-defined substrate. Supported bilayers formed by vesicle fusion represent an attractive substrate fo...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2010.04.036
更新日期:2010-07-21 00:00:00
abstract::Membrane domains known as rafts are rich in cholesterol and sphingolipids, and are thought to be thicker than the surrounding membrane. If so, monolayers should elastically deform so as to avoid exposure of hydrophobic surfaces to water at the raft boundary. We calculated the energy of splay and tilt deformations nece...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1529/biophysj.104.048223
更新日期:2005-02-01 00:00:00
abstract::Pure Michaelis-Menten enzymes have been studied (i.e., enzymes with a hyperbolic (S, V) behavior in a well-stirred solution). When such enzymes are associated with a structure in vitro, even in the simplest conceivable form (immobilization in a homogeneous gel), they can produce enzymic or transport reactions with man...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(83)84401-4
更新日期:1983-01-01 00:00:00
abstract::We present a single virion method to determine absolute distributions of copy number in the protein composition of viruses and apply it to herpes simplex virus type 1. Using two-color coincidence fluorescence spectroscopy, we determine the virion-to-virion variability in copy numbers of fluorescently labeled tegument ...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1529/biophysj.107.106351
更新日期:2007-08-15 00:00:00
abstract::Histograms of single-molecule Förster resonance energy transfer (FRET) efficiency are often used to study the structures of biomolecules and relate these structures to function. Methods like probability distribution analysis analyze FRET histograms to detect heterogeneities in molecular structure, but they cannot dete...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2011.01.066
更新日期:2011-03-16 00:00:00
abstract::The Green's function technique is applied to a study of breathing modes in a DNA double helix which contains a region of different base pairs from the rest of the double helix. The calculation is performed on a G-C helix in the B conformation with four consecutive base pairs replaced by A-T. The average stretch in hyd...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(90)82570-4
更新日期:1990-03-01 00:00:00
abstract::Two mechanisms for the interaction of alternating electrical fields with biological tissue are the development of heat, via i(2)R losses, and field-induced force effects, via differences in passive electrical properties. It has been shown that for continuous wave (CW) fields in media of physiologic electrical conducti...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(70)86346-9
更新日期:1970-10-01 00:00:00
abstract::A new method for the investigation of ion translocating membrane proteins is presented. Protein containing membrane fragments or vesicles are adsorbed to a solid supported membrane. The solid supported membrane consists of a lipid monolayer on a gold evaporated or gold sputtered glass substrate which is coated with a ...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(93)81379-1
更新日期:1993-02-01 00:00:00
abstract::Many different cell types are able to migrate by formation of a thin actin-based cytoskeletal extension. Recently, it became evident that this extension consists of two distinct substructures, designated lamellipodium and lamellum, which differ significantly in their kinetic and kinematic properties as well as their b...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1529/biophysj.108.134817
更新日期:2008-12-15 00:00:00
abstract::There is a steadily growing body of experimental data describing the diffusion of acetylcholine in the neuromuscular junction and the subsequent miniature endplate currents produced at the postsynaptic membrane. To gain further insights into the structural features governing synaptic transmission, we have performed ca...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(98)77610-6
更新日期:1998-10-01 00:00:00
abstract::Artificial lipidic bilayers are widely used as a model for the lipid matrix in biological cell membranes. We use the Pockels electro-optical effect to investigate the properties of an artificial lipidic membrane doped with nonlinear molecules in the outer layer. We report here what is believed to be the first electro-...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2009.08.055
更新日期:2009-12-02 00:00:00
abstract::We present a theory for proton diffusion through an immobilized protein membrane perfused with an electrolyte and a buffer. Using a Nernst-Planck equation for each species and assuming local charge neutrality, we obtain two coupled nonlinear diffusion equations with new diffusion coefficients dependent on the concentr...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(79)85274-1
更新日期:1979-01-01 00:00:00