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[Trans-membrane potential in Entamoeba]
M Noriega-Martínez1, J Cerbón-Solórzano
1Departamento dé Bioquímica, Centro de Investigación y de Estudios Avanzados del IPN, México, D.F.
Archivos De Investigacion Medica
|January 1, 1990
Summary
Entamoeba species possess a negative membrane potential, crucial for substrate uptake. This electrical gradient influences nutrient transport and can be modulated by external conditions.
Area of Science:
- Cell Biology
- Biophysics
Background:
- The membrane potential in Entamoeba is a key factor driving substrate uptake.
- Understanding this potential is vital for comprehending nutrient transport mechanisms in these protozoan parasites.
Purpose of the Study:
- To quantify the membrane potential in Entamoeba invadens PZ.
- To investigate the influence of depolarizing conditions on membrane potential.
- To continuously monitor membrane potential in Entamoeba invadens PZ and Entamoeba histolytica HM1.
Main Methods:
- Utilized the Nernst equation with 86Rb+ distribution in the presence of valinomycin to determine membrane potential.
- Employed the fluorescent lipophilic cation diisopropylthiodicarbocyanine for continuous membrane potential recording.
- Induction of hyperpolarization and depolarization to assess dye response.
Main Results:
- A membrane potential of -36 mV was determined for Entamoeba invadens PZ using 86Rb+.
- High external K+ concentration with valinomycin diminished membrane potential.
- Diisopropylthiodicarbocyanine fluorescence changes correlated with induced membrane potential variations in both species.
Conclusions:
- Entamoeba species exhibit an inside-negative membrane potential.
- This potential is a significant driving force for the accumulation of positively charged substrates.
- The fluorescent dye diisopropylthiodicarbocyanine is a reliable tool for monitoring membrane potential dynamics in Entamoeba.