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Thermo-sensitive response based on the membrane fluidity adaptation in Paramecium multimicronucleatum
Taichi Toyoda1, Yoshinori Hiramatsu, Toshiaki Sasaki
1Biophysical Dynamics Laboratories, Graduate School of Frontier Bioscience, Osaka University, Toyonaka, Osaka 560-8531, Japan.
The Journal of Experimental Biology
|August 18, 2009
Summary
Paramecium cells exhibit a temperature-sensitive response linked to membrane fluidity. Cooling triggers membrane depolarization, suggesting fluidity changes activate temperature-sensitive channels in these protozoa.
Area of Science:
- Cell Biology
- Membrane Biophysics
- Protozoology
Background:
- Protozoa like Paramecium exhibit thermo-sensitive responses.
- Membrane lipid fluidity is crucial for cellular function and response to stimuli.
Purpose of the Study:
- To investigate the relationship between thermo-sensitive membrane depolarization and membrane lipid fluidity in Paramecium.
- To understand the role of homeoviscous adaptation in temperature sensitivity.
Main Methods:
- Utilized Paramecium multimicronucleatum as a model organism.
- Measured membrane depolarization in response to cooling stimuli.
- Assessed membrane fluidity using the fluorescent dye laurdan.
- Manipulated membrane fluidity with procaine and benzyl alcohol.
Main Results:
- Cooling stimulus induced transient membrane depolarization, peaking at the culture temperature.
- Membrane fluidity remained constant at culture temperature (homeoviscous adaptation) but rapidly decreased upon cooling.
- Abolition of cooling-induced depolarization occurred when membrane fluidity was altered by chemical additives.
Conclusions:
- Cooling-induced depolarization in Paramecium is closely linked to changes in membrane lipid fluidity.
- Rapid decreases in membrane fluidity below a homeoviscous set point may activate temperature-sensitive ion channels.
- Homeoviscous adaptation plays a role in maintaining cellular function across different temperatures.
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