Open AccessRegulation of the plasma membrane potential in Pneumocystis carinii
Author(s) -
VanderHeyden Nicole,
McLaughlin Gerald L.,
Docampo Roberto
Publication year - 2000
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.2000.tb08979.x
Subject(s) - pneumocystis carinii , chemistry , microbiology and biotechnology , biology , human immunodeficiency virus (hiv) , virology , pneumocystis jirovecii
Many protists use a H + gradient across the plasma membrane, the proton motive force, to drive nutrient uptake. This force is generated in part by the plasma membrane potential (Δ Ψ ). We investigated the regulation of the Δ Ψ in Pneumocystis carinii using the potentiometric fluorescent dye bisoxonol. The steady state Δ Ψ in a buffer containing Na + and K + (standard buffer) was found to be −78±8 mV. In the absence of Na + and K + (NMG buffer) or Cl − (gluconate buffer), Δ Ψ was not significantly changed suggesting that cation and anion conductances do not play a significant role in the regulation of Δ Ψ in P. carinii . The Δ Ψ was also not affected by inhibitors of the Na + /K + ‐ATPase, ouabain (1 mM), and the K + /H + ‐ATPase, omeprazole (1 mM). In contrast, inhibitors of the plasma membrane H + ‐ATPase, dicyclohexylcarbodiimide (100 μM), N ‐ethylmaleimide (100 μM) and diethylstilbestrol (25 μM), significantly depolarized the Δ Ψ to −43±7, −56±5 and −40±12 mV, respectively. The data support that the plasma membrane H + ‐ATPase plays a significant role in the regulation of Δ Ψ in P. carinii .