Showing papers in "Biophysical Journal in 2000"

TL;DR: A new method for the size-distribution analysis of polymers by sedimentation velocity analytical ultracentrifugation that exploits the ability of Lamm equation modeling to discriminate between the spreading of the sedimentation boundary arising from sample heterogeneity and from diffusion is described.

TL;DR: It is discovered that changes in tissue rigidity and strain could play an important controlling role in a number of normal and pathological processes involving cell locomotion, including morphogenesis, the immune response, and wound healing.

TL;DR: To test this hypothesis, peak-to-peak headgroup thicknesses h(pp) of bilayers were obtained from x-ray diffraction of multibilayer arrays at controlled relative humidities and showed that poly-cis unsaturated chain bilayers are thinner and more flexible than saturated/monounsaturated chain Bilayers.

TL;DR: The solution properties, including hydrodynamic quantities and the radius of gyration, of globular proteins are calculated from their detailed, atomic-level structure, using bead-modeling methodologies described in the previous article, using a HYDROPRO public-domain computer program.

TL;DR: It is shown theoretically that fields of geomagnetic field strength and weaker can produce significantly different reaction yields for different alignments of the radical pairs with the magnetic field.

TL;DR: The effect of various drugs affecting the integrity of different components of the cytoskeleton on the elasticity of two fibroblast cell lines was investigated by elasticity measurements with an atomic force microscope (AFM).

TL;DR: A model with a staggered array of platelets that is in better agreement with results on molecular packing in collagen fibrils and that accounts for an increase of both elastic modulus and fracture stress with the amount of mineral in the fibril is proposed.

TL;DR: A strong correlation exists between the denaturation transitions as observed by calorimetry and the changes in secondary structure derived from circular dichroism, after both heat- and low-pH-induced denaturation, a significant fraction of the secondary structure remains.

TL;DR: Experimental (2)H NMR measurements for the homologous series of 1, 2-diacyl-sn-glycero-3-phosphocholines with perdeuterated saturated chains show that the lateral packing of phospholipids is more sensitive to the headgroup methylation than to the acyl chain length.

TL;DR: Interestingly, examination of the probe coverage as a function of strand length suggests that adsorbed thiol-ssDNA oligonucleotides shorter than 24 bases tend to organize in end-tethered, highly extended configurations for which the long-term surface coverage is largely independent of oligon nucleotide length.

TL;DR: It is proposed that thickness fluctuations is the explanation to the observed system-size dependence of equilibrium-projected area per lipid.

TL;DR: P pH-sensitive green fluorescent protein-based sensors (pHluorins) of synaptic vesicle cycling at nerve terminals are characterized and a theoretical analysis of the expected signals using this approach and guidelines for future reporter development are provided.

TL;DR: To establish laser-tracking microrheology (LTM) as a new technique for quantifying cytoskeletal mechanics, this work measures viscoelastic moduli with wide bandwidth (5 decades) within living cells and provides estimates of solid versus liquid behavior at different frequencies.

TL;DR: The use of multi-photon excitation microscopy to study thin samples may be limited by increased photobleaching, as the high photon flux used in these experiments can potentially lead to higher-order photon interactions within the focal volume.

TL;DR: A new tethered polymer-supported planar lipid bilayer system was developed, which permitted us to reconstitute integral membrane proteins in a laterally mobile form and a model for the interaction of these proteins with the underlying polymer is discussed.

TL;DR: The correlation between the prominent changes in lysis tension and water permeability indicate that major changes occur in chain packing and cohesive interactions when two or more cis-double bonds alternate with saturated bonds along a chain.

TL;DR: The mechanical energy that can be deposited in the DNA double helix before force induced melting occurs was found to decrease with increasing temperature, and this energy correlates with the base-pairing free enthalpy DeltaG(bp)(T) of DNA.

TL;DR: By slowing AP depolarization and shortening APD, Na(+)-overload acts to enhance inducibility of reentrant arrhythmias and predisposes the myocardium to arrh rhythmogenic delayed afterdepolarizations.

TL;DR: The specific membrane capacitance (C(m) of a neuron influences synaptic efficacy and determines the speed with which electrical signals propagate along dendrites and unmyelinated axons, and may be treated as a "biological constant" across many classes of neuron.

TL;DR: Crystallization of the membrane pores provides possibilities for diffraction studies that might provide useful information on the pore structures.

TL;DR: The proposed method for determining intracellular free calcium concentration from single-wavelength fluorescence signals does not require independent estimates of resting [Ca(2+)] but relies on the measurement of fluorescence close to indicator saturation during an experiment, which makes it well suited to [ Ca( 2+)] indicators for which saturation can be achieved under physiological conditions.

TL;DR: The first characterization of the morphology of lipid domains in unsupported lipid bilayers is reported, finding a homogeneous fluorescence distribution in the GUV images at temperatures corresponding to the fluid region in all lipid mixtures.

TL;DR: This article describes the classification of K+-channel-blocking peptides belonging to family 2 peptides and comprising 30-40 amino acids linked by three or four disulfide bridges, and provides evidence for the existence of 12 molecular subfamilies, named alpha-KTx1-12, containing 49 different peptides.

TL;DR: The mechanical response of the channel structure at distances as large as 10-20 A from the ions in the selectivity filter appears to play an important role in the concerted transition.

TL;DR: It is unequivocally demonstrated that the mean-field approximation in the Poisson-Nernst-Planck theory breaks down in narrow ion channels that have radii smaller than the Debye length.

TL;DR: If either the slip mode conductance of the Na(+) channel or the reverse mode of theNa(+)/Ca(2+) exchanger are to contribute to the contractile force, the fuzzy space must extend outside of the dyad.

TL;DR: Chemomechanical transduction was studied in single fibers isolated from human skeletal muscle containing different myosin isoforms and the main difference between slow and fast fibers was reproduced by increasing the rate constant for the hydrolysis step, which was rate limiting at low loads.

TL;DR: In the crystallographic structure of the V66E mutant, a chain of water molecules was seen that hydrates the buried Glu-66 and links it with bulk solvent, providing compelling and unprecedented experimental evidence that solvent penetration can contribute significantly to the high apparent polarizability inside proteins.

TL;DR: This work has provided visual and detailed information on liposome coalescence (fusion) onto solid supports and demonstrated how the atomic force microscope can be used to study the process.

TL;DR: An extensive molecular dynamics simulation study of water hydrating the protein Ribonuclease A, at a series of temperatures in cluster, crystal, and powder environments suggests that water translational motion is necessary for the structural relaxation in proteins.