Elemental composition of polyphosphate-containing vacuoles and cytoplasm of Leishmania major

Ca2+ Content and Expression of an Acidocalcisomal Calcium Pump Are Elevated in Intracellular Forms ofTrypanosoma cruzi

“…Similar calcium-containing electron-dense vacuoles have also been described for other trypanosomatids such as Trypanosoma cyclops (60), Trypanosoma rhodesiense (65), and Leishmania major (26) and were named polyphosphate (60) or electron-dense (26,60) vacuoles. These vacuoles were examined by energy-dispersive X-ray microanalysis (26,60,65) and in some cases were also observed by scanning transmission electron microscopy of whole cells (26), as were the electron-dense organelles found in T. cruzi (15). Acidocalcisomes have been found in all trypanosomatids examined to date (14, 28,43,58,59), which further supports the suggestion that they correspond to the electron-dense vacuoles described for all these parasites.…”

Inhibition of Ca2+ release from Trypanosoma brucei acidocalcisomes by 3,5-dibutyl-4-hydroxytoluene: role of the Na+/H+ exchanger

“…T. cruzi epimastigotes were also shown to possess electron-dense vacuoles containing large amounts of magnesium, potassium, calcium, phosphorus and zinc [22]. Electron-probe X-ray microanalysis of L. major promastigotes demonstrated that their electron-dense vacuoles were also rich in phosphorus, magnesium, calcium, sodium and zinc [23]. Further work on the correspondence of acidocalcisomes and electrondense vacuoles in different trypanosomatids is underway in our laboratory.…”

“…It is possible that acidocalcisomes correspond to what has been described before in Trypanosoma cyclops [20], Trypanosoma Received 19 March 1997/3 July 1997 ; accepted 13 August 1997 rhodesiense [21], T. cruzi [22] and Leishmania major [23] as polyphosphate [20] or electron-dense [21][22][23] vacuoles. These vacuoles were detected by energy-dispersive X-ray microanalysis [20][21][22][23]. When initially observed in T. cyclops [20] they were termed polyphosphate bodies, on the basis of a high phosphorus content and an appearance similar to algal polyphosphate bodies, although the nature of the phosphate compound present was not chemically analysed.…”

A Pyrophosphatase Regulating Polyphosphate Metabolism in Acidocalcisomes Is Essential for Trypanosoma brucei Virulence in Mice

“…This compartment, initially named the acidocalcisome in T. brucei, was shown to be implicated in storage of cations and phosphate (7), regulation of intracellular pH (8,9), and osmoregulation (10,11). To better understand the relation between polyP metabolism and its cellular role, studies were performed on the polyP composition and on the characterization of enzymes involved in the metabolism of these compounds.…”