Observable effects of Ca 2+ buffers on local Ca 2+  signals

2010 ◽  
Vol 368 (1933) ◽  
pp. 5597-5603 ◽  
Author(s):  
Guillermo Solovey ◽  
Silvina Ponce Dawson
Keyword(s):  
High Resolution ◽  
Transport Properties ◽  
Calcium Entry ◽  
Calcium Signals ◽  
Physiological Processes ◽  
New Information ◽  
Inositol 1,4,5 Trisphosphate

Calcium signals participate in a large variety of physiological processes. In many instances, they involve calcium entry through inositol 1,4,5-trisphosphate (IP 3 ) receptors (IP 3 Rs), which are usually organized in clusters. Recent high-resolution optical experiments by Smith & Parker have provided new information on Ca 2+ release from clustered IP 3 Rs. In the present paper, we use the model recently introduced by Solovey & Ponce Dawson to determine how the distribution of the number of IP 3 Rs that become open during a localized release event may change by the presence of Ca 2+ buffers, substances that react with Ca 2+ , altering its concentration and transport properties. We then discuss how buffer properties could be extracted from the observation of local signals.

Stereo Electron Microscopy Applied to High Resolution Freeze-Etch Replicas

1970 ◽  
Vol 28 ◽  
pp. 306-307
Author(s):  
L. Andrew Staehelin
Keyword(s):  
Electron Microscopy ◽  
Plastic Deformation ◽  
High Resolution ◽  
Smooth Surfaces ◽  
Small Particles ◽  
Membrane Surfaces ◽  
Wide Acceptance ◽  
New Information ◽  
Number Of Particles ◽  
Small Holes

Freeze-etched membranes usually appear as relatively smooth surfaces covered with numerous small particles and a few small holes (Fig. 1). In 1966 Branton (1“) suggested that these surfaces represent split inner mem¬brane faces and not true external membrane surfaces. His theory has now gained wide acceptance partly due to new information obtained from double replicas of freeze-cleaved specimens (2,3) and from freeze-etch experi¬ments with surface labeled membranes (4). While theses studies have fur¬ther substantiated the basic idea of membrane splitting and have shown clearly which membrane faces are complementary to each other, they have left the question open, why the replicated membrane faces usually exhibit con¬siderably fewer holes than particles. According to Branton's theory the number of holes should on the average equal the number of particles. The absence of these holes can be explained in either of two ways: a) it is possible that no holes are formed during the cleaving process e.g. due to plastic deformation (5); b) holes may arise during the cleaving process but remain undetected because of inadequate replication and microscope techniques.

scholarly journals New Membrane-Forming Aromatic Co-Poly(amide-imide)s: Influence of the Chemical Structure on the Morphological, Thermal and Transport Properties

Membranes ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 91
Author(s):  
Svetlana V. Kononova ◽  
Danila A. Kuznetsov ◽  
Galina N. Gubanova ◽  
Elena V. Kruchinina ◽  
Anatoly Ya. Volkov ◽  
...  
Keyword(s):  
Transport Properties ◽  
Chemical Structure ◽  
Film Formation ◽  
Membrane Properties ◽  
Morphological Parameters ◽  
Asymmetric Membranes ◽  
Residual Solvent ◽  
New Information ◽  
Film Preparation ◽  
Separation Problems

Polymer film membranes are used to solve specific separation problems that dictate structural requirements. Structural and morphological parameters of film membranes based on glassy polyheteroarylenes can be controlled in the process of preparation from solutions that opens up prospects for obtaining structured membranes required for targeted separation. In the case of aromatic poly(amide-imide)s, the possibility of controlling film formation and structure virtually has not been studied. In the present work, a series of homologous co-poly(amide-imide)s differing in the number of repeating units with carboxyl-substituted aromatic fragments was synthesized by polycondensation. Comparative analysis of the processes of formation of membranes with different morphologies based on these polymers under equal conditions was performed. New information was obtained about the influence of the amounts of carboxyl groups and the residual solvent on structural properties of asymmetric membranes. The influence of these factors on transport properties of dense membranes under pervaporation conditions was studied. It was demonstrated that in the case of carboxyl-containing poly(amide-imide)s, the domains formed during film preparation had a significant effect on membrane properties.

scholarly journals Glucocorticoid-mediated Inhibition of Lck Modulates the Pattern of T Cell Receptor-induced Calcium Signals by Down-regulating Inositol 1,4,5-Trisphosphate Receptors

2009 ◽  
Vol 284 (46) ◽  
pp. 31860-31871 ◽  
Author(s):  
Michael W. Harr ◽  
Yiping Rong ◽  
Martin D. Bootman ◽  
H. Llewelyn Roderick ◽  
Clark W. Distelhorst
Keyword(s):  
T Cell ◽  
T Cell Receptor ◽  
Cell Receptor ◽  
Calcium Signals ◽  
Inositol 1,4,5 Trisphosphate

Evaluation of Anorectal Function by High Resolution Anorectal Manometry (HRAM) in the Lithotomy Gynecological Position. What New Information Does this Position Provides?

2017 ◽  
Vol 152 (5) ◽  
pp. S318
Author(s):  
Gabriela Rojas-Loureiro ◽  
Fausto Daniel Garcia-Garcia ◽  
Paulo Cesar Gomez-Castaños ◽  
Mercedes Amieva-Balmori ◽  
Jose M. Remes Troche
Keyword(s):  
High Resolution ◽  
Anorectal Manometry ◽  
Anorectal Function ◽  
New Information

Freeze-etching studies on muscle

1971 ◽  
Vol 261 (837) ◽  
pp. 139-142 ◽  
Keyword(s):  
High Resolution ◽  
Striated Muscle ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Low Resolution ◽  
Three Dimensional Structure ◽  
Membrane Particles ◽  
New Information ◽  
Biological Interest ◽  
Freeze Etching

The technique of freeze-etching is illustrated with reference to striated muscle. Besides features of immediate biological interest, the material demonstrates various ways in which the process may be used in general to yield new information. These fall broadly into two classes: ( a ) qualitative: visualizing structures not readily seen by other methods, for example, general three-dimensional structure (low resolution) and membrane particles (high resolution); ( b ) quantitative, for example, the distribution of membrane features over extensive uneven surfaces (low and high resolution).

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