Related Experiment Video
Updated: Jan 14, 2026

07:17
Single-Cell Calcium Imaging for Studying the Activation of Calcium Ion Channels
Published on: December 13, 2024
1.7K
Calcium channels in Paramecium aurelia
Summary
Paramecium swimming reversal relies on calcium channels. Mutants with defective calcium channels show altered behavior and barium resistance, revealing distinct gene functions in channel gating and pore formation.
Area of Science:
- Cell Biology
- Neuroscience
- Genetics
Background:
- Swimming direction reversal in Paramecium is mediated by calcium influx via excitable-membrane calcium channels.
- Mutants resistant to barium toxicity were previously identified, exhibiting altered swimming behavior.
Purpose of the Study:
- To investigate the role of calcium channels in Paramecium swimming behavior using barium-resistant mutants.
- To elucidate the specific functions of different genes within the calcium channel complex.
Main Methods:
- Selection of Paramecium aurelia mutants based on barium resistance.
- Behavioral analysis of swimming reversal in wild-type and mutant strains.
- Electrophysiological studies to assess calcium channel function and anomalous rectification.
Main Results:
- Barium-resistant mutants (pawn genes) displayed reduced swimming reversal.
- Mutants exhibited longer survival in barium solutions, with pwB mutants showing higher resistance than pwA.
- Electrophysiology confirmed defective calcium activation in all mutants and anomalous rectification defects in pwB mutants.
- A model proposed distinct roles for pwA (depolarization-sensitive gate) and pwB (pore function) gene products.
Conclusions:
- The study identifies specific gene mutations affecting calcium channel function in Paramecium.
- The findings differentiate the roles of pwA and pwB gene products in calcium channel operation.
- The stability of the calcium channel structure was also characterized, with a half-life of 5-8 days.
Related Concept Videos
Feedback Regulation of Calcium Concentration
3.9K
Calcium is an essential signaling molecule required for various cellular functions. Calcium pumps and ion channels on cell and organellar membranes, such as those on the endoplasmic reticulum (ER), regulate calcium concentrations inside the cell. They remain closed, keeping the cytosolic calcium levels low at a resting state.
Various transmembrane receptors, such as G protein-coupled receptors (GPCRs), elicit a response to extracellular signals by increasing cytosolic calcium. Activated GPCRs...
Various transmembrane receptors, such as G protein-coupled receptors (GPCRs), elicit a response to extracellular signals by increasing cytosolic calcium. Activated GPCRs...
3.9K
The Role of Ion Channels in Neuronal Computation
3.6K
A postsynaptic neuron usually receives numerous impulses from several other presynaptic neurons. The axon hillock of the postsynaptic neuron integrates all these signals and determines the likelihood of firing an action potential.
Sometimes a single EPSP is strong enough to induce an action potential in the postsynaptic neuron. However, multiple presynaptic inputs must often create EPSPs around the same time for the postsynaptic neuron to be sufficiently depolarized to fire an action potential....
Sometimes a single EPSP is strong enough to induce an action potential in the postsynaptic neuron. However, multiple presynaptic inputs must often create EPSPs around the same time for the postsynaptic neuron to be sufficiently depolarized to fire an action potential....
3.6K
Mechanically-gated Ion Channels
7.6K
Mechanically-gated ion channels are proteins found in eukaryotic and prokaryotic cell membranes that open in response to mechanical stress. Tension, compression, swelling, and shear stress can alter the conformation of the protein, opening a transmembrane channel that allows the passage of ions for signal transmission. In eukaryotes, mechanically-gated channels are distributed in several regions like the neurons, lungs, skin, bladder, and heart, where they play critical roles in numerous...
7.6K
Voltage-gated Ion Channels
10.3K
Voltage-gated ion channels are transmembrane proteins that open and close in response to changes in the membrane potential. They are present on the membranes of all electrically excitable cells such as neurons, heart, and muscle cells.
Generally, all voltage-gated ion channels have a 'voltage-sensing domain' that spans the lipid bilayer. The charged residues in the sensor move in response to the membrane potential changes that open the channel allowing ions movement. There are several...
Generally, all voltage-gated ion channels have a 'voltage-sensing domain' that spans the lipid bilayer. The charged residues in the sensor move in response to the membrane potential changes that open the channel allowing ions movement. There are several...
10.3K
Ion Channels
91.1K
The movement of ions like sodium, potassium, and calcium into and out of the cell is essential to maintain the electrochemical gradient in living cells. The ion channels—a class of membrane transport proteins—help maintain this ionic gradient for the smooth functioning of physiological activities such as maintaining cell size and volume, conducting nerve impulses, and gas and nutrient exchange.
Ion channels are specialized integral membrane proteins on the plasma membrane that allow...
Ion channels are specialized integral membrane proteins on the plasma membrane that allow...
91.1K
Non-gated Ion Channels
8.0K
Ion channels are specialized proteins on the plasma membrane that allow charged ions to pass down their electrochemical gradient. Their main function is to maintain the membrane potential which is critical for cell viability. These channels are either gated or non-gated and can transport more than a thousand ions within milliseconds for the cellular event to occur.
Compared to the gated ion channels, the non-gated channels, also known as leakage or passive channels, have no gating mechanism....
Compared to the gated ion channels, the non-gated channels, also known as leakage or passive channels, have no gating mechanism....
8.0K

