Effect of starvation on cytoplasmic pH, proton motive force, and viability of an acidophilic bacterium, Thiobacillus acidophilus.

摘要: The question of whether Thiobacillus acidophilus maintains its cytoplasmic pH at values close to neutrality by active or passive means was explored subjecting the organism long-term starvation (up 22 days). Starving cells maintained a delta 2 3 U throughout starvation, although cellular poly-beta-hydroxybutyric acid and ATP, proton motive force, culture viability were low not detectable after 200 h. Cells exposed azide plus N,N9-dicyclohexylcarbodiimide immediately exhibited characteristics starved for more than Thus, large in T. absence ATPase activity, respiration, significant levels cell therefore dependent on chemiosmotic ionic pumping. transition from metabolically an inactive state accompanied increase positive membrane potential, which nearly completely compensated cells. longevity acidophile during comparable that reported previously neutrophiles, loss occurred because acidification cytoplasm but apparently energy depletion.