Calcium Indicator Solution

2020 ◽  
Vol 2020 (12) ◽  
pp. pdb.rec107201
Keyword(s):  
Indicator Solution ◽  
Calcium Indicator

A new family of fluorescent calcium indicators designed to resist leakage or for measuring calcium near membranes

1994 ◽  
Vol 52 ◽  
pp. 168-169
Author(s):  
Martin Poenie ◽  
Akwasi Minta ◽  
Charles Vorndran
Keyword(s):  
Metal Binding ◽  
Acetoxymethyl Ester ◽  
Binding Properties ◽  
Fura 2 ◽  
New Family ◽  
Anion Transporter ◽  
Calcium Indicator ◽  
Calcium Indicators ◽  
High Calcium ◽  
Intracellular Compartmentalization

The use of fura-2 as an intracellular calcium indicator is complicated by problems of rapid dye leakage and intracellular compartmentalization which is due to a probenecid sensitive anion transporter. In addition there is increasing evidence for localized microdomains of high calcium signals which may not be faithfully reported by fura-2.We have developed a new family of fura-2 analogs aimed at addressing some of these problems. These new indicators are based on a modified bapta which can be readily derivatized to produce fura-2 analogs with a variety of new properties. The modifications do not affect the chromophore and have little impact on the spectral and metal binding properties of the indicator. One of these new derivatives known as FPE3 is a zwitterionic analog of fura-2 that can be loaded into cells as an acetoxymethyl ester and whose retention in cells is much improved. The improved retention of FPE3 is important for both cuvettebased measurements of cell suspensions and for calcium imaging.

Calcium Dynamics and Compartmentalization in Leech Neurons

2005 ◽  
Vol 94 (6) ◽  
pp. 4430-4440 ◽  
Author(s):  
Sofija Andjelic ◽  
Vincent Torre
Keyword(s):  
Information Processing ◽  
Action Potential ◽  
Action Potentials ◽  
Time Course ◽  
Ccd Camera ◽  
Calcium Dynamics ◽  
Single Action ◽  
Single Action Potential ◽  
Calcium Indicator ◽  
Mechanosensory Neurons

Calcium dynamics in leech neurons were studied using a fast CCD camera. Fluorescence changes (Δ F/ F) of the membrane impermeable calcium indicator Oregon Green were measured. The dye was pressure injected into the soma of neurons under investigation. Δ F/ F caused by a single action potential (AP) in mechanosensory neurons had approximately the same amplitude and time course in the soma and in distal processes. By contrast, in other neurons such as the Anterior Pagoda neuron, the Annulus Erector motoneuron, the L motoneuron, and other motoneurons, APs evoked by passing depolarizing current in the soma produced much larger fluorescence changes in distal processes than in the soma. When APs were evoked by stimulating one distal axon through the root, Δ F/ F was large in all distal processes but very small in the soma. Our results show a clear compartmentalization of calcium dynamics in most leech neurons in which the soma does not give propagating action potentials. In such cells, the soma, while not excitable, can affect information processing by modulating the sites of origin and conduction of AP propagation in distal excitable processes.

Abstract 17071: Cell Communication Inference in Macrophages

Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Nika Taghdiri ◽  
Kevin R King ◽  
David Calcagno ◽  
Zhenxing Fu ◽  
Kenneth Huang ◽  
...  
Keyword(s):  
Image Analysis ◽  
Analytical Methods ◽  
Cell Injury ◽  
Diffusion Mechanism ◽  
Cell Communication ◽  
In Vivo Studies ◽  
Cell Dynamics ◽  
Calcium Indicator

Introduction: Tissue macrophages play diverse roles in the cardiovascular system during health and disease. They have diverse functions within tissues, but our understanding of their dynamics is limited because most macrophage characterization assays are destructive and have low temporal resolution. We asked whether these cells are dynamic and interconnected. Methods: Here, we describe experimental and analytical methods for measuring cell dynamics and inferring communication between cells in vitro and in vivo. We created a mouse (Csf1r-Cre x GCaMP5) expressing the Cre-inducible genetically encoded calcium indicator GCaMP5 under the regulation of the innate immune promoter, Csf1r, to non-destructively quantify high-frequency cell dynamics and differentiated them in culture using m-CSF. We developed custom image analysis routines and parameterization strategies for classifying calcium responses. Results: Our studies revealed that calcium reporter BMDMs display minimal fluctuations at baseline but exhibit a dynamic response to immunogenic DNA sensing. DNA-induced isolated cell injury and death, which precipitated cell communication that spread with a velocity of [9μm/s], consistent with an extracellular diffusion mechanism. We developed quantitative image analysis methods that corrected for random calcium fluctuations and identified statistically significant areas of correlated calcium changes suggestive of communication. An analytical pipeline enabled quantification of calcium spike dynamics and correlations of dynamic calcium profiles of single cell sharing a local microenvironment. This resulted in an “improbable synchrony” metric that allowed localization of communication in time and space. We adapted the pipeline for in vivo studies and tested them in a dorsal window chamber model using intravital microscopy. At 2Hz sampling frequency, we identified 27 potential communication events as they responded to complex microenvironmental cues in vivo. Conclusion: The experimental and analytical methods for inferring cell communication provide a new quantitative toolkit for investigating known as-yet undiscovered cell communication pathways.

scholarly journals Thy1 transgenic mice expressing the red fluorescent calcium indicator jRGECO1a for neuronal population imaging in vivo

PLoS ONE ◽  
2018 ◽  
Vol 13 (10) ◽  
pp. e0205444 ◽  
Author(s):  
Hod Dana ◽  
Ondrej Novak ◽  
Michael Guardado-Montesino ◽  
James W. Fransen ◽  
Amy Hu ◽  
...  
Keyword(s):  
Transgenic Mice ◽  
Neuronal Population ◽  
Calcium Indicator ◽  
Population Imaging

[Ca2+]i signaling in pregnant human myometrium

1994 ◽  
Vol 267 (1) ◽  
pp. E77-E87 ◽  
Author(s):  
S. E. Szal ◽  
J. T. Repke ◽  
E. W. Seely ◽  
S. W. Graves ◽  
C. A. Parker ◽  
...  
Keyword(s):  
Cesarean Section ◽  
Calcium Concentration ◽  
Isometric Force ◽  
Full Term ◽  
Ionized Calcium ◽  
Human Myometrium ◽  
Term Pregnancy ◽  
Force Development ◽  
Calcium Indicator

The purpose of the present study was to determine the changes in intracellular ionized calcium concentration ([Ca2+]i) or [Ca2+]i sensitivity accompanying spontaneous and agonist-induced contraction of human myometrium at term pregnancy, as well as to quantify the response to three prototypical agonists: 1) oxytocin, 2) vasopressin, and 3) phenylephrine. Uterine biopsies were obtained at the time of cesarean section from patients who delivered at or near full-term gestation. These preparations were used to measure isometric force development and [Ca2+]i levels with the luminescent calcium indicator aequorin. Concentration-response relationships were determined with respect to isometric force development in the presence of the agonist. [Ca2+]i-force relationships were determined with respect to spontaneous phasic contractions, as well as agonist-induced phasic and tonic contractions. The results provide evidence that the phasic nature of term human myometrium is due to 1) the resting [Ca2+]i level being less than the calcium threshold for contractions and 2) the inability of the tissue to maintain high [Ca2+]i levels for prolonged periods of time. In addition, calcium-independent mechanisms of regulation were suggested by the relatively minor calcium sensitizing action of oxytocin and the observation that relaxation of tonic contractions preceded the fall in [Ca2+]i levels.

scholarly journals Green fluorescent genetically encoded calcium indicator based on calmodulin/M13-peptide from fungi

PLoS ONE ◽  
2017 ◽  
Vol 12 (8) ◽  
pp. e0183757 ◽  
Author(s):  
Natalia V. Barykina ◽  
Oksana M. Subach ◽  
Kiryl D. Piatkevich ◽  
Erica E. Jung ◽  
Aleksey Y. Malyshev ◽  
...  
Keyword(s):  
Calcium Indicator ◽  
Green Fluorescent

scholarly journals SELECTIVE MERCURIMETRIC TITRATION ASSAY OF CHLORIDE CONCENTRATION IN THE WATER OF GREEN COCONUTS USING NOVEL INDICATOR SYSTEM

2017 ◽  
Vol 9 (3) ◽  
pp. 268
Author(s):  
Shivaji Rangnath Labhade
Keyword(s):  
Statistical Treatment ◽  
Chloride Concentration ◽  
Potassium Thiocyanate ◽  
Indicator System ◽  
Coconut Water ◽  
Stoichiometric Ratio ◽  
Indicator Solution ◽  
End Point ◽  
Red Color

Objective: A selective mercurimetric titration procedure is proposed for the assay of chloride concentration in the water of green coconut using mercury(II) nitrate [(Hg(NO3)2] reagent and iron(III) nitrate [Fe(NO3)3] with synthetically prepared mercury(II) thiocyanate [Hg(SCN)2] indicator system.Methods: An indicator solution was prepared by titrating Hg(NO3)2 against potassium thiocyanate (KSCN) till a red color end point using Fe(NO3)3. Then a known amount of Hg(NO3)2 was added to indicator solution and titrated against the water of green coconut till the original red color reappeared.Results: The concentration of chloride present in the volume of coconut water utilized in between these two end points was found to be reacting in the 2:1 stoichiometric ratio with the Hg(NO3)2 taken in the second step of the titration. The statistical treatment of the experimental data obtained by using standard solutions of sodium chloride (NaCl) indicates that the procedure is precise and accurate. The phosphate, sulfate, organic compounds and inorganic minerals present in the coconut water did not interfere with the measurement of chloride by this procedure. Both the cationic mineral value (was also determined by complexometric titration) and chloride concentration in the coconut water were found to be decreased with the development of the coconuts.Conclusion: The proposed procedure of determination of chloride concentration in the water of green coconut is simple, reliable and inexpensive. This procedure is excellent for determination of chloride in the acidic solution without precise adjustment of the pH for detection of the end point. Owing to the homogenous reaction condition no titration errors those are commonly encountered by co-precipitation in the argentometric assay of chloride. 

Signal Propagation Along Unidimensional Neuronal Networks

2005 ◽  
Vol 94 (5) ◽  
pp. 3406-3416 ◽  
Author(s):  
Ofer Feinerman ◽  
Menahem Segal ◽  
Elisha Moses
Keyword(s):  
Large Scale ◽  
Signal Transmission ◽  
Signal Propagation ◽  
High Amplitude ◽  
Adhesive Material ◽  
One Dimensional ◽  
Calcium Indicator ◽  
Scale Population ◽  
Population Burst ◽  
Linear Signal

Dissociated neurons were cultured on lines of various lengths covered with adhesive material to obtain an experimental model system of linear signal transmission. The neuronal connectivity in the linear culture is characterized, and it is demonstrated that local spiking activity is relayed by synaptic transmission along the line of neurons to develop into a large-scale population burst. Formally, this can be treated as a one-dimensional information channel. Directional propagation of both spontaneous and stimulated bursts along the line, imaged with the calcium indicator Fluo-4, revealed the existence of two different propagation velocities. Initially, a small number of neighboring neurons fire, leading to a slow, small and presumably asynchronous wave of activity. The signal then spontaneously develops to encompass much larger and further populations, and is characterized by fast propagation of high-amplitude activity, which is presumed to be synchronous. These results are well described by an existing theoretical framework for propagation based on an integrate-and-fire model.

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