Showing papers in "Biophysical Journal in 1999"

TL;DR: Application of the method is illustrated by the restoration of a ribosome-like model structure and more realistically by the determination of the shape of several proteins from experimental x-ray scattering data.

TL;DR: It is found that the propulsive thrust for fibroblast locomotion is imparted to the substratum within 15 micrometers of the leading edge, demonstrating that the lamellipodium of the fibro Blast is able to generate intense traction stress.

TL;DR: Wavelength scanning of the surface fluorescence of the heart under various conditions after accumulation of T MRM indicated that the mitochondrial matrix-induced wavelength shift of TMRM also occurs in the heart cytosol, eliminating the use of this approach in the intact heart.

TL;DR: It is demonstrated that this nanopore behaves as a detector that can rapidly discriminate between pyrimidine and purine segments along an RNA molecule.

TL;DR: The development of a decomposition technique (space-frequency singular value decomposition) that is shown to be a useful means of characterizing the image data and an algorithm, based on multitaper methods, for the removal of approximately periodic physiological artifacts arising from cardiac and respiratory sources are developed.

TL;DR: The viscoelastic properties of the cytoplasm of J774 macrophages are measured with a recently developed microrheometer and the magnetophoretic motion of the ferromagnetic beads at a constant magnetic force is analyzed, suggesting that the cy toplasm is composed of clusters of densely packed and cross-linked filaments separated by soft regions.

TL;DR: While both excitation alternatives work well for intracellular FCS in thin preparations, 2PE can substantially improve signal quality in turbid preparations like plant cells and deep cell layers in tissue, thereby preserving long-term signal acquisition.

TL;DR: A wavelength-tunable optical trap was employed in which the microscope objective transmission was fully characterized throughout the near infrared, in conjunction with a sensitive, rotating bacterial cell assay, and the intensity dependence for photodamage was linear, supporting a single-photon process.

TL;DR: The photon counting histogram (PCH) analysis constitutes a novel tool for extracting quantities from fluorescence fluctuation data, i.e., the measured photon counts per molecule and the average number of molecules within the observation volume.

TL;DR: An improvement to the Marko and Siggia interpolation formula of Bustamante et al (Science 1994, 265:1599-1600) that is useful for fitting experimental data is applied to the experimental elasticity curve of single DNA molecules.

TL;DR: In hepatocytes and MH1C1 cells coloaded with Co2+ and calcein AM, treatment with MTP inducers caused a rapid, though limited, decrease in mitochondrial calce in fluorescence, which was significantly reduced by CsA, and MTP likely fluctuates rapidly between open and closed states in intact cells.

TL;DR: Optical tweezers are used to apply calibrated forces to human erythrocytes, via small silica beads bound to their membrane, and the shear modulus mu is inferred from measurements of the cell deformation in the small strain linear regime.

TL;DR: This paper presents a compilation of quantitative data on couplons in a variety of skeletal and cardiac muscles, useful in modeling calcium release events, both macroscopic and microscopic ("sparks").

TL;DR: This treatment shows that dramatic structural and thermodynamic changes can occur at particular cholesterol mole fractions without any stoichiometric complex formation and the increase in acyl chain order parameter in cholesterol-phospholipid mixtures.

TL;DR: It is concluded that Ni(2+) is only a selective blocker of alpha1H currents and that the concentrations required to block alpha1G and alpha1I will also affect high-voltage-activated calcium currents.

TL;DR: Not only did flexible macromolecules exhibit greater mobility in the gel than did comparable-size rigid spherical particles, they also proved to be a more useful probe of available space between fibers.

TL;DR: With electrode arrays fabricated using direct write electron beam lithography, it is shown that different types of submicron latex spheres can be spatially separated and it is demonstrated that tobacco mosaic virus and herpes simplex virus can be manipulated and spatially separation in a microelectrode array.

TL;DR: In this paper, the authors used x-ray crystallography to determine the structures of sperm whale myoglobin (Mb) in four different ligation states (unligated, ferric aquomet, oxygenated, and carbonmonoxygenated) to a resolution of better than 1.2 A.

TL;DR: Clot rigidity was enhanced by increasing fiber and branchpoint densities at greater fibrinogen concentrations, and network morphology is only minimally altered by the FXIIIa-catalyzed cross-linking reaction, which seems to augment clot rigidity most likely by the stiffening of existing fibers.

TL;DR: In this paper, the authors adapted a laser scanning microscope with a titanium sapphire femtosecond pulsed laser and transmission optics to produce live cell images based on the nonlinear optical phenomenon of second harmonic generation (SHG).

TL;DR: Results of statistical thermodynamic calculations of the equilibrium pressure profile and bilayer thickness are reported and possible roles of cholesterol, highly unsaturated fatty acids and small solutes in modulating membrane protein function are suggested and unambiguous experimental tests of the pressure profile hypothesis are suggested.

TL;DR: This study develops a model for a single cell electroporated by an external electric field and uses it to investigate the effects of shock strength and rest potential on the transmembrane potential V(m) and pore density N around the cell.

TL;DR: The results show how spatial responses following localized tetanic stimuli, although complex, can be accounted for by a simple rule for activity-dependent modification.

TL;DR: It is suggested that the tether force on blebs primarily contains only the membranes tension term and that the membrane tension may be uniform over the cell surface, and that an internal osmotic pressure inflates the blebs, and the pressure calculated from the Law of Laplace is similar to independent measurements of intracellular pressures.

TL;DR: This work analyzes the kinetic process of failure for a bond loaded by pulling the polymer linkages at constant speed and finds that when linked by either type of polymer chain, a bond is likely to fail at lower force under steady separation than through stiff linkages.

TL;DR: It is suggested that cells maintain a plasma membrane reservoir to buffer against changes in membrane tension and that the reservoir is increased with membrane tension or disruption of the cytoskeleton.

TL;DR: The resolution limit of fluorescence correlation spectroscopy for two-component solutions is investigated theoretically and experimentally and shows that there exists a concentration threshold for the less abundant component below which it is not possible to determine with statistical means alone that two particles are in solution.

TL;DR: In this article, a polynucleotide is driven through a proteinaceous pore by an electric field, and the diffusive motion of a polymer threaded through a narrow channel with which it may have strong interactions is studied.

TL;DR: The goal of this study was to determine which neural elements are excited by microstimulation of the central nervous system by using a cable model of a neuron including an axon, initial segment, axon hillock, soma, and simplified dendritic tree to study excitation with an extracellular point source electrode.

TL;DR: In this paper, the atomic force microscope (AFM) tip and sample are adjusted by pH and electrolytes to distribute the force applied to the AFM tip over a large sample area.