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Membrane-potential changes in vacuoles isolated from storage roots of red beet (Beta vulgarisL.)

โœ Scribed by Anthony J. Miller; John J. Brimelow; Philip John

Publisher
Springer-Verlag
Year
1984
Tongue
English
Weight
733 KB
Volume
160
Category
Article
ISSN
0032-0935

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โœฆ Synopsis

The membrane potential in vacuoles isolated from storage roots of red beet (Beta vulgaris L.) has been studied by following changes in the fluorescence of the dye 3,3'-diethylthiodicarbocyanine iodide, and by determining the uptake of the lipophilic triphenylmethylphosphonium cation.

The vacuoles have a membrane potential, internal negative, which is estimated to be around -60 inV. These potentials become less negative by nearly 10 mV on addition of ATP. This ATP-dependent depolarisation is inhibited by the protonophore carbonylcyanide p-trifluoromethoxyphenylhydrazone and by the ATPase inhibitors, N,N'dicyclohexylcarbodiimide and trimethyltin chloride, but it is largely insensitive to sodium orthovanadate. Fusicoccin had no significant effect on the isolated vacuoles, but its addition to excised tissue caused a hyperpolarisation of the cells measured using a microelectrode.

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