Abstract:
:Measurements of transepithelial electrical impedance of continuously short-circuited A6 epithelia were made at audio frequencies (0.244 Hz to 10.45 kHz) to investigate the time course and extent to which prostaglandin E(2) (PGE(2)) modulates Cl(-) transport and apical membrane capacitance in this cell-cultured model epithelium. Apical and basolateral membrane resistances were determined by nonlinear curve-fitting of the impedance vectors at relatively low frequencies (<50 Hz) to equations (Păunescu, T. G., and S. I. Helman. 2001. Biophys. J. 81:838--851) where depressed Nyquist impedance semicircles were characteristic of the membrane impedances under control Na(+)-transporting and amiloride-inhibited conditions. In all tissues (control, amiloride-blocked, and amiloride-blocked and furosemide-pretreated), PGE(2) caused relatively small (< approximately 3 microA/cm(2)) and rapid (<60 s) maximal increase of chloride current due to activation of a rather large increase of apical membrane conductance that preceded significant activation of Na(+) transport through amiloride-sensitive epithelial Na(+) channels (ENaCs). Apical membrane capacitance was frequency-dependent with a Cole-Cole dielectric dispersion whose relaxation frequency was near 150 Hz. Analysis of the time-dependent changes of the complex frequency-dependent equivalent capacitance of the cells at frequencies >1.5 kHz revealed that the mean 9.8% increase of capacitance caused by PGE(2) was not correlated in time with activation of chloride conductance, but rather correlated with activation of apical membrane Na(+) transport.
journal_name
Biophys Jjournal_title
Biophysical journalauthors
Păunescu TG,Helman SIdoi
10.1016/S0006-3495(01)75746-3subject
Has Abstractpub_date
2001-08-01 00:00:00pages
852-66issue
2eissn
0006-3495issn
1542-0086pii
S0006-3495(01)75746-3journal_volume
81pub_type
杂志文章abstract::A method for fabricating biomimetic surfaces from intact cell membranes is described. A monolayer of alkanethiol on gold is covered by a second layer derived from the components of erythrocyte membranes either by self-assembly or by Langmuir-Blodgett methods. The resulting asymmetric hybrid layer was characterized by ...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(97)78334-6
更新日期:1997-12-01 00:00:00
abstract::The chromophore of octopus rhodopsin is 11-cis retinal, linked via a protonated Schiff base to the protein backbone. Its stable photoproduct, metarhodopsin, has all-trans retinal as its chromphore. The Schiff base of acid metarhodopsin (lambda max = 510 nm) is protonated, whereas that of alkaline metarhodopsin (lambda...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(90)82394-8
更新日期:1990-08-01 00:00:00
abstract::The cornea is the primary refractive lens in the eye and transmits >90% of incident visible light. It has been suggested that the development of postoperative corneal haze could be due to an increase in light scattering from activated corneal stromal cells. Quiescent keratocytes are thought to produce crystallins that...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2015.08.046
更新日期:2015-10-20 00:00:00
abstract::The membrane-lytic peptide melittin has previously been shown to form pores in lipid bilayers that have been described in terms of two different structural models. In the "barrel stave" model the bilayer remains more or less flat, with the peptides penetrating across the bilayer hydrocarbon region and aggregating to f...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1529/biophysj.104.049817
更新日期:2005-03-01 00:00:00
abstract::Transcription factors use both protein-DNA and protein-protein interactions to assemble appropriate complexes to regulate gene expression. Although most transcription factors operate as monomers or dimers, a few, including the E26 transformation-specific family repressors Drosophila melanogaster Yan and its human homo...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2016.11.901
更新日期:2017-01-10 00:00:00
abstract::Toad ventricles were externally driven by periodic pulses while monophasic action potential (MAP) signals were recorded in seven excised and seven in situ ventricles. As the frequency was slowly increased in steps, the stimulated tissue displayed several dynamic characteristics. Hierarchies of periodic behavior, like ...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(89)82673-6
更新日期:1989-08-01 00:00:00
abstract::The molecular cascade that controls switching of the direction of rotation of Escherichia coli flagellar motors is well known, but the conformational changes that allow the rotor to switch are still unclear. The signaling molecule CheY, when phosphorylated, binds to the C-ring at the base of the rotor, raising the pro...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2017.12.001
更新日期:2018-02-06 00:00:00
abstract::We used micron-sized latex spheres to probe the phase state and the viscoelastic properties of dimyristoylphosphatidylcholine (DMPC) bilayers as a function of temperature. One or two particles were manipulated and stuck to a DMPC giant vesicle by means of an optical trap. Above the fluid-gel main transition temperatur...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(00)76296-5
更新日期:2000-07-01 00:00:00
abstract::The phase transitions of dipalmitoylphosphatidylethanolamine (DPPE) in excess water have been examined by low-angle time-resolved x-ray diffraction and calorimetry at low scan rates. The lamellar subgel/lamellar liquid-crystalline (L(c) --> L(alpha)), lamellar gel/lamellar liquid-crystalline (L(beta) --> L(alpha)), an...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(92)81873-8
更新日期:1992-03-01 00:00:00
abstract::The orientational ordering of beta-carotene and crocetin embedded in lamellar model membranes has been investigated by angle-resolved resonance Raman scattering at a temperature well above the phase transition of the lipid chains. It is shown that the ordering of the carotenoids is dependent on the chemical compositio...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(84)84269-1
更新日期:1984-06-01 00:00:00
abstract::A variety of amphiphilic helical peptides have been shown to exhibit a transition from adsorbing parallel to a membrane surface at low concentrations to inserting perpendicularly into the membrane at high concentrations. Furthermore, this transition has been correlated to the peptides' cytolytic activities. X-ray lame...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(95)80418-2
更新日期:1995-06-01 00:00:00
abstract::More and more researchers are interested in imaging living (Henderson, 1994) or fixed cells in their natural environment using the atomic force microscope (AFM). However, the AFM tip interacts strongly with the sample, and its z range freedom is limited to a few micrometers. This means that the cells to be imaged have...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(95)80344-9
更新日期:1995-05-01 00:00:00
abstract::Adsorption of lambda-phage on sensitive bacteria Escherichia coli is a classical problem but not all issues have been resolved. One of the outstanding problems is the rate of adsorption, which in some cases appears to exceed the theoretical limit imposed by the law of random diffusion. We revisit this problem by condu...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1529/biophysj.106.102962
更新日期:2007-07-01 00:00:00
abstract::Iberiotoxin, a toxin purified from the scorpion Buthus tamulus is a 37 amino acid peptide having 68% homology with charybdotoxin. Charybdotoxin blocks large conductance Ca(2+)-activated K+ channels at nanomolar concentrations from the external side only (Miller, C., E. Moczydlowski, R. Latorre, and M. Phillips. 1985. ...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(92)81630-2
更新日期:1992-08-01 00:00:00
abstract::Voltage-gated sodium channels undergo transitions between open, closed, and inactivated states, enabling regulation of the translocation of sodium ions across membranes. A recently published crystal structure of the full-length prokaryotic NavMs crystal structure in the activated open conformation has revealed the pre...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2018.10.001
更新日期:2018-11-20 00:00:00
abstract::The genetic map of T4 (and T2) bacteriophage is circular but the DNA molecule that is liberated by phenol extraction is a linear duplex of polynucleotide chains. If the genetic map is related to the physical structure of the DNA molecule, the problem arises as to how a linear molecule can give rise to a circular map. ...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/s0006-3495(64)86771-0
更新日期:1964-03-01 00:00:00
abstract::Bax and Bid are proapoptotic proteins of the Bcl-2 family that regulate the release of apoptogenic factors from mitochondria. Although they localize constitutively in the cytoplasm, their apoptotic function is exerted at the mitochondrial outer membrane, and is related to their ability to form transbilayer pores. Here...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1529/biophysj.104.058008
更新日期:2005-06-01 00:00:00
abstract::Tagging of individual proteins with genetically encoded fluorescent proteins (FPs) has been used extensively to study localization and interactions in live cells. Recent developments in single-molecule localization microscopy have enabled the dynamic visualization of individual tagged proteins inside living cells. How...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2016.05.047
更新日期:2016-07-12 00:00:00
abstract::We present elastic and inelastic incoherent neutron scattering data from a series of trehalose glasses diluted with glycerol. A strong correlation with recently published protein stability data in the same series of glasses illustrates that the dynamics at Q >or= 0.71 A(-1) and omega > 200 MHz are important to stabili...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1529/biophysj.103.035519
更新日期:2004-06-01 00:00:00
abstract::This paper presents a study of the influence of normalization errors on size distributions obtained from the analysis of intensity fluctuations by photon correlation spectroscopy. The effects of these errors are demonstrated by means of computer-generated autocorrelation functions simulating light scattered from a mon...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(89)82652-9
更新日期:1989-07-01 00:00:00
abstract::Two independent methods, induced osmosis and solvent drag, were used to determine the reflection coefficients for NaCl (sigma NaCl) in brush border and basolateral membrane vesicles isolated from rabbit proximal tubule. In the induced osmosis method, vesicles loaded with sucrose were subjected to varying inward NaCl g...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(89)82920-0
更新日期:1989-06-01 00:00:00
abstract::Toward quantitative description of protein aggregation, we develop a computationally efficient method to evaluate the potential of mean force between two folded protein molecules that allows for complete sampling of their mutual orientation. Our model is valid at moderate ionic strengths and accounts for the actual ch...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2012.03.025
更新日期:2012-04-18 00:00:00
abstract::The pulling of micropipette electrodes from glass tubing has been treated as a problem of viscous flow coupled with the Newtonian dynamics of the pulling apparatus. Analytical solutions are given from which the taper profile, tip diameter, and pulling time can be obtained. The physical principles of operation of micro...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(80)85150-2
更新日期:1980-03-01 00:00:00
abstract::The accommodation of chain-length mismatch in liquid crystal phase bilayers was examined by using deuterium nuclear magnetic resonance to obtain smoothed orientational order parameter profiles for acyl chains of both components in binary lipid mixture bilayers. Mixtures of dimyristoylphosphatidylcholine (DMPC) and dis...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(95)80219-5
更新日期:1995-02-01 00:00:00
abstract::An analytical electromechanical model of a spherical cell exposed to an alternating electric field was used to calculate shear stress generated in the cellular membrane. Shape deformation of Neurospora crassa (slime) spheroplasts was measured. Statistical analysis permitted empirical evaluation of creep of the cellula...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(92)81866-0
更新日期:1992-03-01 00:00:00
abstract::We studied the effects of permeant ions on the gating of the large conductance Ca(2+)-activated K+ channel from rat skeletal muscle. Rb+ blockade of inward K+ current caused an increase in the open probability as though Rb+ occupancy of the pore interferes with channel closing. In support of this hypothesis, we direct...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(92)81869-6
更新日期:1992-03-01 00:00:00
abstract::The harmonic mode analysis method was used to characterize the conformational deformability of regular Watson-Crick paired, mismatch- and bulge-containing RNA. Good agreement between atomic Debye-Waller factors derived from x-ray crystallography of a regular RNA oligonucleotide and calculated atomic fluctuations was o...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(00)76798-1
更新日期:2000-05-01 00:00:00
abstract::Ion channel behavior can depend strongly on temperature, with faster kinetics at physiological temperatures leading to considerable changes in currents relative to room temperature. These temperature-dependent changes in voltage-dependent ion channel kinetics (rates of opening, closing, inactivating, and recovery) are...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2019.07.030
更新日期:2019-12-17 00:00:00
abstract::Cytoplasmic free Mg(2+) concentration ([Mg(2+)]i) was measured in rat ventricular myocytes with a fluorescent indicator furaptra (mag-fura-2) introduced by AM-loading. By incubation of the cells in a high-K(+) (Ca(2+)- and Mg(2+)-free) solution, [Mg(2+)]i decreased from ? 0.9 mM to 0.2 to 0.5 mM. The lowered [Mg(2+)]i...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2014.09.015
更新日期:2014-11-04 00:00:00
abstract::The resonance Raman spectrum of the second intermediate in the bacteriorhodopsin cycle, bL550, is obtained by a simple flow technique. The Schiff base linkage in this intermediate appears to be protonated, contrary to previous suggestion. The fingerprint region of the spectrum of bL550 does not closely match those of ...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(79)85269-8
更新日期:1979-06-01 00:00:00