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Related Concept Videos

Channel Rhodopsins01:11

Channel Rhodopsins

Most organisms use photoreceptors to sense and respond to light. Examples of photoreceptors include bacteriorhodopsins and bacteriophytochromes in some bacteria, phytochromes in plants, and rhodopsins in the photoreceptor cells of the vertebral retina. The light-sensitive property of these receptors is because of the bound chromophores, such as bilin in the phytochromes and retinal in the rhodopsins.
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Photoreceptors and Visual Pathways01:22

Photoreceptors and Visual Pathways

At the molecular level, visual signals trigger transformations in photopigment molecules, resulting in changes in the photoreceptor cell's membrane potential. The photon's energy level is denoted by its wavelength, with each specific wavelength of visible light associated with a distinct color. The spectral range of visible light, classified as electromagnetic radiation, spans from 380 to 720 nm. Electromagnetic radiation wavelengths exceeding 720 nm fall under the infrared category, whereas...
Feedback Regulation of Calcium Concentration01:27

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Photoreceptors and Plant Responses to Light

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Imaging Ca2+ Dynamics in Cone Photoreceptor Axon Terminals of the Mouse Retina
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Imaging Ca2+ Dynamics in Cone Photoreceptor Axon Terminals of the Mouse Retina

Published on: May 6, 2015

Calcium-sensitive photoproteins.

Marisa Brini1

  • 1Department of Biochemistry, University of Padova, Viale G. Colombo 3, 35131 Padova, Italy. arisa.brini@unipd.it

Methods (San Diego, Calif.)
|October 14, 2008
PubMed
Summary
This summary is machine-generated.

Aequorin is a pioneering photoprotein for measuring intracellular calcium (Ca2+) in organelles. Despite limitations in single-cell imaging and experimental duration, its precise targeting and straightforward calibration offer valuable insights into cellular calcium dynamics.

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Preparation of Living Isolated Vertebrate Photoreceptor Cells for Fluorescence Imaging
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Published on: June 22, 2011

Area of Science:

  • Cell Biology
  • Biochemistry
  • Molecular Imaging

Background:

  • Aequorin, a recombinant Ca2+-sensitive photoprotein, was the first probe for measuring intracellular calcium concentration ([Ca2+]) in organelles of intact cells.
  • This technique enables precise targeting for selective intracellular distribution.

Purpose of the Study:

  • To evaluate the advantages and disadvantages of aequorin-based methods for intracellular calcium measurements.
  • To highlight aequorin's utility in studying cellular calcium dynamics across various compartments.

Main Methods:

  • Utilizing wild-type and low Ca2+-affinity aequorins to cover a broad dynamic range of [Ca2+] (10(-7) to 10(-3)M).
  • Employing a simple algorithm for straightforward calibration of results in [Ca2+].
  • Measuring luminescence in cell populations using simple, low-cost equipment.

Main Results:

  • Aequorin offers a high signal-to-noise ratio and low Ca2+ buffering effect, being nearly insensitive to Mg2+ or pH changes.
  • Advantages include precise targeting, wide dynamic range, straightforward calibration, and accessible equipment.
  • Disadvantages involve low emitted light for single-cell imaging, a necessary reconstitution step, potential issues in high Ca2+ compartments, and the need for cell transfection or stable clones.

Conclusions:

  • Aequorin-based methods provide a powerful, albeit imperfect, tool for quantifying intracellular calcium concentrations.
  • Ongoing research may address limitations to enhance its application in advanced cellular imaging and prolonged experiments.