pH homeostasis in acidophiles

摘要: The acidophilic bacteria comprise an environmentally important group that includes pathogens. A fundamental requirement for existence in strongly acidic environments is generation of a large pH gradient (delta pH) to maintain the cytoplasmic near neutrality and safeguard acid-labile cell constituents. These organisms require capacity extrude H+ across thermodynamic barrier imposed by delta pH. They also need special transport proteins can function environments. quintessential device which acidophiles fulfil these requirements generating positive-inside membrane potential psi) mitigates both force against must be extruded, as well influxing protons into cells. psi generated through passive active mechanisms. former constitutes diffusion Donnan potential, latter involves electrogenic circulation Cl-, operation H+/K+ (Na+) antiporter.