Leishmania donovani amastigotes mobilize organic and inorganic osmolytes during regulatory volume decrease.

Published

Journal Article

The protozoan parasite Leishmania donovani encounters large fluctuations in osmolality as it cycles between its insect vector and human host. The flagellated promastigote exhibits regulatory volume responses involving organic and inorganic osmolytes, but little is known about volume regulation in the clinically relevant amastigote that multiplies within the parasitophorous vacuoles of mammalian host cells. Using a combination of morphological, X-ray microanalytical, and biochemical approaches we determined that non-motile amastigotes respond to hypotonic stress with (1) an amino acid and l-alanine-mediated regulatory volume decrease, and (2) a parallel release of Na+, K+, P (presumably as negatively charged phosphates), and subsequently Cl- from cytoplasm and the cell as a whole. In addition P, Zn2+, and subsequently Ca2+ increase in acidocalcisomes as Cl- content declines in this compartment. This evidence is the first to document subcellular translocation of, and thus a potential role for, zinc in volume regulatory responses. These coordinated changes in organic and inorganic osmolytes demonstrate that amastigote subcellular compartments, particularly acidocalcisomes, function in maintaining ionic homeostasis in the response of Leishmania amastigotes to hypo-osmotic stress.

Full Text

Duke Authors

Cited Authors

  • Lefurgey, A; Gannon, M; Blum, J; Ingram, P

Published Date

  • May 2005

Published In

Volume / Issue

  • 52 / 3

Start / End Page

  • 277 - 289

PubMed ID

  • 15927005

Pubmed Central ID

  • 15927005

International Standard Serial Number (ISSN)

  • 1066-5234

Digital Object Identifier (DOI)

  • 10.1111/j.1550-7408.2005.00030.x

Language

  • eng

Conference Location

  • United States