Intracellular microrheology of motile Amoeba proteus.


:The motility of Amoeba proteus was examined using the technique of passive particle tracking microrheology, with the aid of newly developed particle tracking software, a fast digital camera, and an optical microscope. We tracked large numbers of endogeneous particles in the amoebae, which displayed subdiffusive motion at short timescales, corresponding to thermal motion in a viscoelastic medium, and superdiffusive motion at long timescales due to the convection of the cytoplasm. Subdiffusive motion was characterized by a rheological scaling exponent of 3/4 in the cortex, indicative of the semiflexible dynamics of the actin fibers. We observed shear-thinning in the flowing endoplasm, where exponents increased with increasing flow rate; i.e., the endoplasm became more fluid-like. The rheology of the cortex is found to be isotropic, reflecting an isotropic actin gel. A clear difference was seen between cortical and endoplasmic layers in terms of both viscoelasticity and flow velocity, where the profile of the latter is close to a Poiseuille flow for a Newtonian fluid.


Biophys J


Biophysical journal


Rogers SS,Waigh TA,Lu JR




Has Abstract


2008-04-15 00:00:00














  • Vibrational analysis of nucleic acids. I. The phosphodiester group in dimethyl phosphate model compounds: (CH3O)2PO2-, (CD3O)2PO2-, and (13CH3O)2PO2-.

    abstract::Normal coordinate analyses and vibrational assignments are presented for the dimethyl phosphate anion [(CH3O)2PO2-] and its deuteriomethyl [(CD3O)2PO2-] and carbon-13 [(13CH3O)2PO2-] derivatives in the gauche-gauche conformation. The dimethyl phosphate anion, which is the simplest model for the nucleic acid phosphodie...

    journal_title:Biophysical journal

    pub_type: 杂志文章


    authors: Guan Y,Wurrey CJ,Thomas GJ Jr

    更新日期:1994-01-01 00:00:00

  • Molecular dynamics simulations of the anchoring and tilting of the lung-surfactant peptide SP-B1-25 in palmitic acid monolayers.

    abstract::We have performed molecular dynamics simulations of multiple copies of the lung-surfactant peptide SP-B1-25 in a palmitic acid (PA) monolayer. SP-B1-25 is a shorter version of lung-surfactant protein B, an important component of lung surfactant. Up to 30 ns simulations of 20 wt % SP-B1-25 in the PA monolayers were per...

    journal_title:Biophysical journal

    pub_type: 杂志文章


    authors: Lee H,Kandasamy SK,Larson RG

    更新日期:2005-12-01 00:00:00

  • Resolution of multiphasic reactions by the combination of fluorescence total-intensity and anisotropy stopped-flow kinetic experiments.

    abstract::Multiphasic kinetics are often observed in stopped-flow investigations. To characterize further these kinetic phases, we have developed a methodology whereby fluorescence total intensity and anisotropy stopped-flow data can be combined in a single analysis. Fluorescence total intensity and anisotropy are highly interr...

    journal_title:Biophysical journal

    pub_type: 杂志文章


    authors: Otto MR,Lillo MP,Beechem JM

    更新日期:1994-12-01 00:00:00

  • Protein logic: a statistical mechanical study of signal integration at the single-molecule level.

    abstract::Information processing and decision-making is based upon logic operations, which in cellular networks has been well characterized at the level of transcription. In recent years, however, both experimentalists and theorists have begun to appreciate that cellular decision-making can also be performed at the level of a s...

    journal_title:Biophysical journal

    pub_type: 杂志文章


    authors: de Ronde W,Rein ten Wolde P,Mugler A

    更新日期:2012-09-05 00:00:00

  • Modeling of glucose-induced cAMP oscillations in pancreatic β cells: cAMP rocks when metabolism rolls.

    abstract::Recent advances in imaging technology have revealed oscillations of cyclic adenosine monophosphate (cAMP) in insulin-secreting cells. These oscillations may be in phase with cytosolic calcium oscillations or out of phase. cAMP oscillations have previously been modeled as driven by oscillations in calcium, based on the...

    journal_title:Biophysical journal

    pub_type: 杂志文章


    authors: Peercy BE,Sherman AS,Bertram R

    更新日期:2015-07-21 00:00:00

  • Calcium regulation of myosin-I tension sensing.

    abstract::Myo1b is a myosin that is exquisitely sensitive to tension. Its actin-attachment lifetime increases > 50-fold when its working stroke is opposed by 1 pN of force. The long attachment lifetime of myo1b under load raises the question: how are actin attachments that last >50 s in the presence of force regulated? Like mos...

    journal_title:Biophysical journal

    pub_type: 杂志文章


    authors: Lewis JH,Greenberg MJ,Laakso JM,Shuman H,Ostap EM

    更新日期:2012-06-20 00:00:00

  • Gloeobacter rhodopsin, limitation of proton pumping at high electrochemical load.

    abstract::We studied the photocurrents of a cyanobacterial rhodopsin Gloeobacter violaceus (GR) in Xenopus laevis oocytes and HEK-293 cells. This protein is a light-driven proton pump with striking similarities to marine proteorhodopsins, including the D121-H87 cluster of the retinal Schiff base counterion and a glutamate at po...

    journal_title:Biophysical journal

    pub_type: 杂志文章


    authors: Vogt A,Wietek J,Hegemann P

    更新日期:2013-11-05 00:00:00

  • Molecular heterogeneity of O-acetylserine sulfhydrylase by two-photon excited fluorescence fluctuation spectroscopy.

    abstract::O-acetylserine sulfhydrylase, a homo-dimeric enzyme from Salmonella typhimurium, covalently binds one pyridoxal 5'-phosphate molecule per subunit as a fluorescent coenzyme. Different tautomers of the Schiff base between the coenzyme and lysine 41 generate structured absorption and fluorescence spectra upon one-photon ...

    journal_title:Biophysical journal

    pub_type: 杂志文章


    authors: Chirico G,Bettati S,Mozzarelli A,Chen Y,Müller JD,Gratton E

    更新日期:2001-04-01 00:00:00

  • The origin of nonmonotonic complex behavior and the effects of nonnative interactions on the diffusive properties of protein folding.

    abstract::We present a method for calculating the configurational-dependent diffusion coefficient of a globular protein as a function of the global folding process. Using a coarse-grained structure-based model, we determined the diffusion coefficient, in reaction coordinate space, as a function of the fraction of native contact...

    journal_title:Biophysical journal

    pub_type: 杂志文章


    authors: Oliveira RJ,Whitford PC,Chahine J,Wang J,Onuchic JN,Leite VB

    更新日期:2010-07-21 00:00:00

  • The thermodynamics of general anesthesia.

    abstract::It is known that the action of general anesthetics is proportional to their partition coefficient in lipid membranes (Meyer-Overton rule). This solubility is, however, directly related to the depression of the temperature of the melting transition found close to body temperature in biomembranes. We propose a thermodyn...

    journal_title:Biophysical journal

    pub_type: 杂志文章


    authors: Heimburg T,Jackson AD

    更新日期:2007-05-01 00:00:00

  • Background Suppression in Imaging Gold Nanorods through Detection of Anti-Stokes Emission.

    abstract::Metallic nanoparticles have opened the possibility of imaging, tracking, and manipulating biological samples without time limitations. Their low photoluminescence quantum yield, however, makes them hard to detect under high background conditions. In this study we show that it is possible to image gold nanorods by dete...

    journal_title:Biophysical journal

    pub_type: 杂志文章


    authors: Carattino A,Keizer VIP,Schaaf MJM,Orrit M

    更新日期:2016-12-06 00:00:00

  • Effects of mRNA Degradation and Site-Specific Transcriptional Pausing on Protein Expression Noise.

    abstract::Genetically identical cells exhibit diverse phenotypes even when experiencing the same environment. This phenomenon in part originates from cell-to-cell variability (noise) in protein expression. Although various kinetic schemes of stochastic transcription initiation are known to affect gene expression noise, how post...

    journal_title:Biophysical journal

    pub_type: 杂志文章


    authors: Kim S,Jacobs-Wagner C

    更新日期:2018-04-10 00:00:00

  • Secondary pair charge recombination in photosystem I under strongly reducing conditions: temperature dependence and suggested mechanism.

    abstract::Photoinduced electron transfer in photosystem I (PS I) proceeds from the excited primary electron donor P700 (a chlorophyll a dimer) via the primary acceptor A0 (chlorophyll a) and the secondary acceptor A1 (phylloquinone) to three [4Fe-4S] clusters, Fx, FA, and FB. Prereduction of the iron-sulfur clusters blocks elec...

    journal_title:Biophysical journal

    pub_type: 杂志文章


    authors: Polm M,Brettel K

    更新日期:1998-06-01 00:00:00

  • Photophysics of the fluorescent Ca2+ indicator Fura-2.

    abstract::The photophysics of the complex forming reaction of Ca2+ and Fura-2 are investigated using steady-state and time-resolved fluorescence measurements. The fluorescence decay traces were analyzed with global compartmental analysis yielding the following values for the rate constants at room temperature in aqueous solutio...

    journal_title:Biophysical journal

    pub_type: 杂志文章


    authors: Van den Bergh V,Boens N,De Schryver FC,Ameloot M,Steels P,Gallay J,Vincent M,Kowalczyk A

    更新日期:1995-03-01 00:00:00

  • Modeling Loop Composition and Ion Concentration Effects in RNA Hairpin Folding Stability.

    abstract::The ability to accurately predict RNA hairpin structure and stability for different loop sequences and salt conditions is important for understanding, modeling, and designing larger RNA folds. However, traditional RNA secondary structure models cannot treat loop-sequence and ionic effects on RNA hairpin folding. Here,...

    journal_title:Biophysical journal

    pub_type: 杂志文章


    authors: Zhao C,Zhang D,Jiang Y,Chen SJ

    更新日期:2020-10-06 00:00:00

  • Simultaneous capacitance and amperometric measurements of exocytosis: a comparison.

    abstract::We measured the exocytotic response induced by flash photolysis of caged compounds in isolated mast cells and chromaffin cells. Vesicle fusion was measured by monitoring the cell membrane capacitance. The release of vesicular contents was followed by amperometry. In response to a GTP gamma S stimulus we found that the...

    journal_title:Biophysical journal

    pub_type: 杂志文章


    authors: Oberhauser AF,Robinson IM,Fernandez JM

    更新日期:1996-08-01 00:00:00

  • The nature of sources of bioelectric and biomagnetic fields.

    abstract::The goal of this paper is to examine the origins and relative importance of primary and secondary sources of electric and magnetic fields for excitable tissue. It is shown that for axonal and cardiac tissue a comparison of the relative field strength from both primary and secondary sources shows only the latter to be ...

    journal_title:Biophysical journal

    pub_type: 杂志文章


    authors: Plonsey R

    更新日期:1982-09-01 00:00:00

  • Theory of fluorescence induction in photosystem II: derivation of analytical expressions in a model including exciton-radical-pair equilibrium and restricted energy transfer between photosynthetic units.

    abstract::The theoretical relationships between the fluorescence and photochemical yields of PS II and the fraction of open reaction centers are examined in a general model endowed with the following features: i) a homogeneous, infinite PS II domain; ii) exciton-radical-pair equilibrium; and iii) different rates of exciton tran...

    journal_title:Biophysical journal

    pub_type: 杂志文章


    authors: Lavergne J,Trissl HW

    更新日期:1995-06-01 00:00:00

  • Three-dimensional resolution doubling in wide-field fluorescence microscopy by structured illumination.

    abstract::Structured illumination microscopy is a method that can increase the spatial resolution of wide-field fluorescence microscopy beyond its classical limit by using spatially structured illumination light. Here we describe how this method can be applied in three dimensions to double the axial as well as the lateral resol...

    journal_title:Biophysical journal

    pub_type: 杂志文章


    authors: Gustafsson MG,Shao L,Carlton PM,Wang CJ,Golubovskaya IN,Cande WZ,Agard DA,Sedat JW

    更新日期:2008-06-01 00:00:00

  • Orientation of cross-bridges in skeletal muscle measured with a hydrophobic probe.

    abstract::Cis-parinaric acid (PA) binds to a hydrophobic pocket formed between the heavy chain of myosin subfragment-1 (S1) and the 41-residue N-terminal of essential light chain 1 (A1). The binding is strong (Ka = 5.6 x 10(7) M-1) and rigid (polarization = 0.334). PA does not bind to myofibrils in which A1 has been extracted o...

    journal_title:Biophysical journal

    pub_type: 杂志文章


    authors: Xiao M,Borejdo J

    更新日期:1997-05-01 00:00:00

  • Kinetics of interaction of N epsilon-fluorescein isothiocyanate-lysine-23-cobra alpha-toxin with the acetylcholine receptor.

    abstract::We have studied the kinetics of N epsilon-fluorescein isothiocyanate-lysine-23 cobra alpha-toxin (FITC-toxin) binding to the membrane-associated acetylcholine receptor from the Torpedo californica electric organ. The fluorescent toxin not only enabled us to monitor the binding reaction continuously but also to examine...

    journal_title:Biophysical journal

    pub_type: 杂志文章


    authors: Cheung AT,Johnson DA,Taylor P

    更新日期:1984-02-01 00:00:00

  • Characterization of the chromophore of the third rhodopsin-like pigment of Halobacterium halobium and its photoproduct.

    abstract::Halobacterium halobium contains at least three retinal-containing pigments: bacteriorhodopsin, halorhodopsin, and a third rhodopsin-like pigment (tR) absorbing at approximately 590 nm, tR590. Illumination of tR590 gives rise to a very long-lived blue absorbing photoproduct, tR370. Using high-performance liquid chromat...

    journal_title:Biophysical journal

    pub_type: 杂志文章


    authors: Tsuda M,Nelson B,Chang CH,Govindjee R,Ebrey TG

    更新日期:1985-05-01 00:00:00

  • Potassium ion accumulation at the external surface of the nodal membrane in frog myelinated fibers.

    abstract::Potassium accumulation associated with outward membrane potassium current was investigated experimentally in myelinated fibers and analyzed in terms of two models-three-compartment and diffusion in an unstirred layer. In the myelinated fibers, as in squid giant axons, the three-compartment model satisfactorily describ...

    journal_title:Biophysical journal

    pub_type: 杂志文章


    authors: Moran N,Palti Y,Levitan E,Stämpfli R

    更新日期:1980-12-01 00:00:00

  • Site-specific dichroism analysis utilizing transmission FTIR.

    abstract::Infrared spectroscopy has long been used to examine the average secondary structure and orientation of membrane proteins. With the recent utilization of site-specific isotope labeling (e.g., peptidic 1-(13)C = (18)O) it is now possible to examine localized properties, rather than global averages. The technique of site...

    journal_title:Biophysical journal

    pub_type: 杂志文章


    authors: Arbely E,Kass I,Arkin IT

    更新日期:2003-10-01 00:00:00

  • The osmotic migration of cells in a solute gradient.

    abstract::The effect of a nonuniform solute concentration on the osmotic transport of water through the boundaries of a simple model cell is investigated. A system of two ordinary differential equations is derived for the motion of a single cell in the limit of a fast solute diffusion, and an analytic solution is obtained for o...

    journal_title:Biophysical journal

    pub_type: 杂志文章


    authors: Jaeger M,Carin M,Medale M,Tryggvason G

    更新日期:1999-09-01 00:00:00

  • Lipid Organization in Mixed Lipid Membranes Driven by Intrinsic Curvature Difference.

    abstract::Laurdan fluorescence, novel spectral fitting, and dynamic light scattering were combined to determine lateral lipid organization in mixed lipid membranes of the oxidized lipid, 1-palmitoyl-2-glutaryl-sn-glycero-3-phosphocholine (PGPC), and each of the three bilayer lipids, 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (...

    journal_title:Biophysical journal

    pub_type: 杂志文章


    authors: Ranganathan R,Alshammri I,Peric M

    更新日期:2020-04-21 00:00:00

  • Refractive-index-based screening of membrane-protein-mediated transfer across biological membranes.

    abstract::Numerous membrane-transport proteins are major drug targets, and therefore a key ingredient in pharmaceutical development is the availability of reliable, efficient tools for membrane transport characterization and inhibition. Here, we present the use of evanescent-wave sensing for screening of membrane-protein-mediat...

    journal_title:Biophysical journal

    pub_type: 杂志文章


    authors: Brändén M,Tabaei SR,Fischer G,Neutze R,Höök F

    更新日期:2010-07-07 00:00:00

  • Cardiomyopathy Mutation Alters End-to-End Junction of Tropomyosin and Reduces Calcium Sensitivity.

    abstract::Muscle contraction is governed by tropomyosin (Tpm) shifting azimuthally between three states on F-actin (B-, C-, and M-states) in response to calcium binding to troponin and actomyosin cross-bridge formation. The Tpm coiled coil polymerizes head to tail along the long-pitch helix of F-actin to form continuous superhe...

    journal_title:Biophysical journal

    pub_type: 杂志文章


    authors: Sundar S,Rynkiewicz MJ,Ghosh A,Lehman W,Moore JR

    更新日期:2020-01-21 00:00:00

  • Stochastic versus deterministic variability in simple neuronal circuits: I. Monosynaptic spinal cord reflexes.

    abstract::Long time series of monosynaptic Ia-afferent to alpha-motoneuron reflexes were recorded in the L7 or S1 ventral roots in the cat. Time series were collected before and after spinalization at T13 during constant amplitude stimulations of group Ia muscle afferents in the triceps surae muscle nerves. Using autocorrelatio...

    journal_title:Biophysical journal

    pub_type: 杂志文章


    authors: Chang T,Schiff SJ,Sauer T,Gossard JP,Burke RE

    更新日期:1994-08-01 00:00:00

  • An approach for time-resolved x-ray scattering.

    abstract::Recent biological optical spectroscopic studies have correlated discrete spectroscopic states with biological function in several systems. One of the challenges of molecular biophysics is to correlate structural changes with these spectroscopic states. From small-angle x-ray scattering one can obtain a key structural ...

    journal_title:Biophysical journal

    pub_type: 杂志文章


    authors: Stamatoff J

    更新日期:1979-05-01 00:00:00