Journal of BiophysicsThis is an RSS file. You can use it to subscribe to this data in your favourite RSS reader, such as GoogleReader, or to display this data on your own website or blog. Subscribe to this data using MyMedWorm.Subscribe to this data using GoogleReader.Subscribe to this data using Bloglines.Subscribe to this data using MyYahoo.

This page shows you the latest items in this publication.

17 records returned

Navigation by Induction-Based Magnetoreception in Elasmobranch FishesEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
A quantitative frequency-domain model of induction-based magnetoreception is presented for elasmobranch fishes. We show that orientation with respect to the geomagnetic field can be determined by synchronous detection of electrosensory signals at harmonics of the vestibular frequency. The sensitivity required for this compass-sense mechanism is shown to be less than that known from behavioral experiments. Recent attached-magnet experiments have called into doubt the induction-based mechanism for magnetoreception. We show that the use of attached magnets would interfere with an induction-based mechanism unless relative move...
Source: Journal of Biophysics - October 18, 2009 Category: Physics Source Type: journals

Tropomyosin Period 3 Is Essential for Enhancement of Isometric Tension in Thin Filament-Reconstituted Bovine MyocardiumEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Tropomyosin (Tm) consists of 7 quasiequivalent repeats known as “periods,” and its specific function may be associated with these periods. To test the hypothesis that either period 2 or 3 promotes force generation by inducing a positive allosteric effect on actin, we reconstituted the thin filament with mutant Tm in which either period 2 (Δ2Tm) or period 3 (Δ3Tm) was deleted. We then studied: isometric tension, stiffness, 6 kinetic constants, and the pCa-tension relationship. N-terminal acetylation of Tm did not cause any differences. The isometric tension in Δ2Tm remained unchanged, and wa...
Source: Journal of Biophysics - October 13, 2009 Category: Physics Source Type: journals

Crystal Structural and Functional Analysis of the Putative Dipeptidase from Pyrococcus horikoshii OT3Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The crystal structure of a putative dipeptidase (Phdpd) from Pyrococcus horikoshii OT3 was solved using X-ray data at 2.4 Å resolution. The protein is folded into two distinct entities. The N-terminal domain consists of the general topology of the α/β fold, and the C-terminal domain consists of five long mixed strands, four helices, and two 310 helices. The structure of Phdpd is quite similar to reported structures of prolidases from P. furiosus (Zn-Pfprol) and P. horikoshii (Zn-Phdpd), where Zn ions are observed in the active site resulting in an inactive form. However, Phdpd did not contain meta...
Source: Journal of Biophysics - June 28, 2009 Category: Physics Source Type: journals

Molecular Processes in Biological ThermosensationEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Since thermal gradients are almost everywhere, thermosensation could represent one of the oldest sensory transduction processes that evolved in organisms. There are many examples of temperature changes affecting the physiology of living cells. Almost all classes of biological macromolecules in a cell (nucleic acids, lipids, proteins) can present a target of the temperature-related stimuli. This review discusses some features of different classes of temperature-sensing molecules as well as molecular and biological processes that involve thermosensation. Biochemical, structural, and thermodynamic approaches are applied in th...
Source: Journal of Biophysics - June 10, 2009 Category: Physics Source Type: journals

Antidepressant Interactions with the NMDA NR1-1b SubunitEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The targets for tricyclic antidepressants (TCAs), selective serotonin reuptake inhibitors (SSRIs), and selective norepinephrine reuptake inhibitors (SNRIs) are known to be the serotonin and norepinephrine transport (reuptake) proteins which are embedded in presynaptic nerve terminals and function to bring these neurotransmitters from the synaptic cleft back into the presynaptic neuron. Using a combination of intrinsic and extrinsic fluorescence quenching, Stern-Volmer analysis, and protease protection assays, we have shown that therapeutics from each of these three classes of antidepressants bind to the extracellular S1S2 ...
Source: Journal of Biophysics - June 10, 2009 Category: Physics Source Type: journals

Cell Volume and Sodium Content in Rat Kidney Collecting Duct Principal Cells During Hypotonic ShockEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The purpose of this study was to investigate the time course of the volume-regulatory response and intracellular sodium concentration ([Na+]i) in the principal cells of rat kidney outer medulla collecting duct (OMCD) epithelia during acute swelling in hypotonic medium. Hypotonic shock was created by PBS diluted with 50% of water. Changes in cell volume were measured with calcein quenching method. Intracellular sodium concentration was studied with fluorescence dye Sodium Green. Principal cells of microdissected OMCD fragments swelled very fast. The characteristic time of swelling (τ1) was 0.65±0.05 ...
Source: Journal of Biophysics - June 10, 2009 Category: Physics Source Type: journals

Flexibility of the Cytoplasmic Domain of the Phototaxis Transducer II from Natronomonas pharaonisEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Chemo- and phototaxis systems in bacteria and archaea serve as models for more complex signal transduction mechanisms in higher eukaryotes. Previous studies of the cytoplasmic fragment of the phototaxis transducer (pHtrII-cyt) from the halophilic archaeon Natronomonas pharaonis showed that it takes the shape of a monomeric or dimeric rod under low or high salt conditions, respectively. CD spectra revealed only approximately 24% helical structure, even in 4 M KCl, leaving it an open question how the rod-like shape is achieved. Here, we conducted CD, FTIR, and NMR spectroscopic studies under different conditions to a...
Source: Journal of Biophysics - June 10, 2009 Category: Physics Source Type: journals

Selective Detection of NADPH Oxidase in Polymorphonuclear Cells by Means of NAD(P)H-Based Fluorescence Lifetime ImagingEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
NADPH oxidase (NOX2) is a multisubunit membrane-bound enzyme complex that, upon assembly in activated cells, catalyses the reduction of free oxygen to its superoxide anion, which further leads to reactive oxygen species (ROS) that are toxic to invading pathogens, for example, the fungus Aspergillus fumigatus. Polymorphonuclear cells (PMNs) employ both nonoxidative and oxidative mechanisms to clear this fungus from the lung. The oxidative mechanisms mainly depend on the proper assembly and function of NOX2. We identified for the first time the NAD(P)H-dependent enzymes involved in such oxidative mechanisms by means of biexp...
Source: Journal of Biophysics - June 10, 2009 Category: Physics Source Type: journals

Roots of Diversity RelationsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The species-area relationship is one of the central generalizations in ecology; however, its origin has remained a puzzle. Since ecosystems are understood as energy transduction systems, the regularities in species richness are considered to result from ubiquitous imperatives in energy transduction. From a thermodynamic point of view, organisms are transduction mechanisms that distribute an influx of energy down along the steepest gradients to the ecosystem's diverse repositories of chemical energy, that is, populations of species. Transduction machineries, that is, ecosystems assembled from numerous species, may emerg...
Source: Journal of Biophysics - June 10, 2009 Category: Physics Source Type: journals

Role of the Endothelium during Tumor Cell Metastasis: Is the Endothelium a Barrier or a Promoter for Cell Invasion and Metastasis?Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The malignancy of cancer disease depends on the ability of the primary tumor to metastasize to distant organs. The process of the metastasis formation has largely been analyzed, but still main pathways regarding the extravasation step at the end of the metastasis formation process are controversially discussed. An agreement has been reached about the importance of the endothelium to promote metastasis formation either by enhancing the growth of the primary tumor or by homing (targeting) the tumor cells to blood or lymph vessels. The mechanical properties of the invading tumor cells become the focus of several studies, but ...
Source: Journal of Biophysics - June 10, 2009 Category: Physics Source Type: journals

Roots of Diversity RelationsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The species-area relationship is one of the central generalizations in ecology; however, its origin has remained a puzzle. Since ecosystems are understood as energy transduction systems, the regularities in species richness are considered to result from ubiquitous imperatives in energy transduction. From a thermodynamic point of view, organisms are transduction mechanisms that distribute an influx of energy down along the steepest gradients to the ecosystem's diverse repositories of chemical energy, that is, populations of species. Transduction machineries, that is, ecosystems assembled from numerous species, may emerg...
Source: Journal of Biophysics - December 11, 2008 Category: Physics Source Type: journals

Selective Detection of NADPH Oxidase in Polymorphonuclear Cells by Means of NAD(P)H-Based Fluorescence Lifetime ImagingEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
NADPH oxidase (NOX2) is a multisubunit membrane-bound enzyme complex that, upon assembly in activated cells, catalyses the reduction of free oxygen to its superoxide anion, which further leads to reactive oxygen species (ROS) that are toxic to invading pathogens, for example, the fungus Aspergillus fumigatus. Polymorphonuclear cells (PMNs) employ both nonoxidative and oxidative mechanisms to clear this fungus from the lung. The oxidative mechanisms mainly depend on the proper assembly and function of NOX2. We identified for the first time the NAD(P)H-dependent enzymes involved in such oxidative mechanisms by means of biexp...
Source: Journal of Biophysics - November 17, 2008 Category: Physics Source Type: journals

Flexibility of the Cytoplasmic Domain of the Phototaxis Transducer II from Natronomonas pharaonisEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Chemo- and phototaxis systems in bacteria and archaea serve as models for more complex signal transduction mechanisms in higher eukaryotes. Previous studies of the cytoplasmic fragment of the phototaxis transducer (pHtrII-cyt) from the halophilic archaeon Natronomonas pharaonis showed that it takes the shape of a monomeric or dimeric rod under low or high salt conditions, respectively. CD spectra revealed only approximately 24% helical structure, even in 4 M KCl, leaving it an open question how the rod-like shape is achieved. Here, we conducted CD, FTIR, and NMR spectroscopic studies under different conditions to a...
Source: Journal of Biophysics - October 16, 2008 Category: Physics Source Type: journals

Cell Volume and Sodium Content in Rat Kidney Collecting Duct Principal Cells During Hypotonic ShockEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The purpose of this study was to investigate the time course of the volume-regulatory response and intracellular sodium concentration ([Na+]i) in the principal cells of rat kidney outer medulla collecting duct (OMCD) epithelia during acute swelling in hypotonic medium. Hypotonic shock was created by PBS diluted with 50% of water. Changes in cell volume were measured with calcein quenching method. Intracellular sodium concentration was studied with fluorescence dye Sodium Green. Principal cells of microdissected OMCD fragments swelled very fast. The characteristic time of swelling (τ1) was 0.65±0.05 ...
Source: Journal of Biophysics - July 27, 2008 Category: Physics Source Type: journals

Antidepressant Interactions with the NMDA NR1-1b SubunitEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The targets for tricyclic antidepressants (TCAs), selective serotonin reuptake inhibitors (SSRIs), and selective norepinephrine reuptake inhibitors (SNRIs) are known to be the serotonin and norepinephrine transport (reuptake) proteins which are embedded in presynaptic nerve terminals and function to bring these neurotransmitters from the synaptic cleft back into the presynaptic neuron. Using a combination of intrinsic and extrinsic fluorescence quenching, Stern-Volmer analysis, and protease protection assays, we have shown that therapeutics from each of these three classes of antidepressants bind to the extracellular S1S2 ...
Source: Journal of Biophysics - June 5, 2008 Category: Physics Source Type: journals

Molecular Processes in Biological ThermosensationEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Since thermal gradients are almost everywhere, thermosensation could represent one of the oldest sensory transduction processes that evolved in organisms. There are many examples of temperature changes affecting the physiology of living cells. Almost all classes of biological macromolecules in a cell (nucleic acids, lipids, proteins) can present a target of the temperature-related stimuli. This review discusses some features of different classes of temperature-sensing molecules as well as molecular and biological processes that involve thermosensation. Biochemical, structural, and thermodynamic approaches are applied in th...
Source: Journal of Biophysics - June 3, 2008 Category: Physics Source Type: journals