pH Homeostasis in Leishmania donovani Amastigotes and Promastigotes

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 85; no. 20; pp. 7602 - 7606
• Main Authors: Glaser, Theresa A., Baatz, John E., Kreishman, George P., Mukkada, Antony J.
• Format: Journal Article
• Language: English
• Published: Washington, DC National Academy of Sciences of the United States of America 01.10.1988; National Acad Sciences
• Subjects: Active transport; Amastigotes; Animals; Biochemistry. Physiology. Immunology. Molecular biology; Biological and medical sciences; Biological Transport, Active; Chemical equilibrium; Dimethadione - metabolism; Fundamental and applied biological sciences. Psychology; Homeostasis; Human protozoal diseases; Hydrogen-Ion Concentration; Infectious diseases; Leishmania donovani; Leishmania donovani - metabolism; Leshmaniasis; Life cycle. Host-agent relationship. Pathogenesis; Magnetic Resonance Spectroscopy; Mathematics; Medical sciences; Methylamines; Parasites; Parasitic diseases; Phosphates; Phosphates - metabolism; Promastigotes; Protons; Protozoa; Protozoal diseases; Tropical medicine; Protozoa; Leishmania donovani; Rhizoflagellata; Homeostasis; PH; Developmental stage; Amastigote; Promastigote; Pathogen
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.85.20.7602

Intracellular pH and pH gradients of Leishmania donovani amastigotes and promastigotes were determined over a broad range of extracellular pH values. Intracellular pH was determined by 31P NMR and by equilibrium distribution studies with 5,5-dimethyloxazolidine-2,4-dione or methylamine. Promastigotes maintain intracellular pH values close to neutral between extracellular pH values of 5.0 and 7.4. Amastigote intracellular pH is maintained close to neutral at external pH values as low as 4.0. Both life stages maintain a positive pH gradient to an extracellular pH of 7.4, which is important for active transport of substrates. Treatment with ionophores, such as nigericin and carbonyl cyanide m-chlorophenylhydrazone and the ATPase inhibitor dicyclohexylcarbodiimide, reduced pH gradients in both stages. Maintenance of intracellular pH in the physiologic range is especially relevant for the survival of the amastigote in its acidic in vivo environment.