Leishmania amazonensis: effects of heat shock on ecto-ATPase activity.

Autor: Peres-Sampaio CE; Faculdade de Enfermagem-FENF, Centro Biomédico, Universidade do Estado do Rio de Janeiro-UERJ, Av. 28 de setembro 87, Vila Isabel, 20551-030, Rio de Janeiro, RJ, Brazil., de Almeida-Amaral EE, Giarola NL, Meyer-Fernandes JR
Jazyk: angličtina
Zdroj: Experimental parasitology [Exp Parasitol] 2008 May; Vol. 119 (1), pp. 135-43. Date of Electronic Publication: 2008 Jan 24.
DOI: 10.1016/j.exppara.2008.01.003
Abstrakt: In this work we demonstrated that promastigotes of Leishmania amazonensis exhibit an Mg-dependent ecto-ATPase activity, which is stimulated by heat shock. The Mg-dependent ATPase activity of cells grown at 22 and 28 degrees C was 41.0+/-5.2 nmol Pi/h x 10(7)cells and 184.2+/-21.0 nmol Pi/h x 10(7)cells, respectively. When both promastigotes were pre-incubated at 37 degrees C for 2h, the ATPase activity of cells grown at 22 degrees C was increased to 136.4+/-10.6 nmol Pi/h x 10(7) whereas that the ATPase activity of cells grown at 28 degrees C was not modified by the heat shock (189.8+/-10.3 nmol Pi/h x 10(7)cells). It was observed that Km of the enzyme from cells grown at 22 degrees C (Km=980.2+/-88.6 microM) was the same to the enzyme from cells grown at 28 degrees C (Km=901.4+/-91.9 microM). In addition, DIDS (4,4'-diisothiocyanatostilbene 2,2'-disulfonic acid) and suramin, two inhibitors of ecto-ATPases, also inhibited similarly the ATPase activities from promastigotes grown at 22 and 28 degrees C. We also observed that cells grown at 22 degrees C exhibit the same ecto-phosphatase and ecto 3'- and 5'-nucleotidase activities than cells grown at 28 degrees C. Interestingly, cycloheximide, an inhibitor of protein synthesis, suppressed the heat-shock effect on ecto-ATPase activity of cells grown at 22 degrees C were exposed at 37 degrees C for 2h. A comparison between the stimulation of the Mg-dependent ecto-ATPase activity of virulent and avirulent promastigotes by the heat shock showed that avirulent promastigotes had a higher stimulation than virulent promastigotes after heat stress.
Databáze: MEDLINE
Externí odkaz: