The Na+-responsive ntp operon is indispensable for homeostatis of K+ and Na+ in Enterococcus hirae at limited proton potential.
Enterococcus hirae ATCC 9790 grew well in Na+-deficient, low-K+ medium, but growth was inhibited by carbonylcyanide m-chlorophenylhydrazone (CCCP). Growth inhibition and decrease of cellular K+ levels in the presence of CCCP were relieved by the addition of Na+ and a high concentration of K+. In contrast, in the mutant defective in Na+-ATPase or the NtpJ component of the KtrII K+ uptake system, CCCP-induced growth inhibition was rescued by a high concentration of K+ but not of Na+. These transporters are thus indispensable for homeostatis of K+ and Na+ at low proton potential.
Kawano
M
M
Faculty of Pharmaceutical Sciences, Chiba University, Inage-ku, Chiba 263-8522, Japan.
Igarashi
K
K
Kakinuma
Y
Y
D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone / Q000494:pharmacology; D016983:Enterococcus / Q000235:genetics / Q000378:metabolism*; D006706:Homeostasis; D009876:Operon; D011188:Potassium / Q000378:metabolism*; D012964:Sodium / Q000378:metabolism*
D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone; D012964:Sodium; D011188:Potassium