SUMMARY: At an external pH of 3.0, spheroplasts of the acidophilic bacterium possessed a ΔpH of 2.9 units, a membrane potential of +86 mV, and a protonmotive force of -88 mV. The ultrastructure of the whole cells or spheroplasts showed no unusual features. At given concentrations, SCN was more effective in collapsing ΔpH in spheroplasts than in whole cells, indicating a lower permeability barrier in the former. However the Δp values in spheroplasts were very similar to those in the whole cells, and respiratory chain inhibitors a protonophore, and an ATPase inhibitor, alone or in various combinations, were equally ineffective in collapsing ΔpH in whole cells and in spheroplasts. Thus, it is unlikely that the permeability barrier of the outer membrane accounted for the low values of measured Δp or the ineffectiveness of various agents in collapsing ΔpH in whole cells of this organism; this confirms our previous suggestion that a sizeable ΔpH in can be maintained by non-chemiosmotic means.


Article metrics loading...

Loading full text...

Full text loading...


Most cited this month Most Cited RSS feed

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error