Ecto-phosphatase activity profile in two Trypanosoma rangeli strains.
Bayer-Santos, E. 2; Kiffer-Moreira T. 1; Fonseca de Souza, A. L. 1;
Gomes, S. A. O. 1 - 3; Grisard, E. C.2; Meyer-Fernandes J.R. 1
1 Laboratório de Bioquímica Celular - IBqM, CCS, UFRJ.
2 Laboratório de Protozoologia – Departamento de Microbiologia e Parasitologia – UFSC.
3Núcleo de Morfologia e Ultraestrutura de Artrópodes, Departamento de Entomologia, Instituto Oswaldo Cruz - FIOCRUZ.
e-mail: tkiffer@bioqmed.ufrj.br
The detection of phosphatase activities on the parasites surface presents great relevance to the comprehension of its physiological roles, such as cell adhesion, nutrients acquisition, virulence and signal transduction. The phosphatases that the catalytic site faced to the external medium are called as ecto-phosphatases. Previous studies showed distinct ecto-
fosfatase activities on the surface of epimastigotes forms from T. rangeli, H14 strain. In order to compare these activities between other strains of T. rangeli, we are now investigating the ecto-phosphatase activity in two different strains of T. rangeli: Choachi and SC58. Our results demonstrated that epimastigotes forms from Choachi strain were able to hydrolyze the artificial substrate, p-NPP, 4-fold higher than Sc58 strain. Various divalent cations, metal chelators and inhibitors were tested. Some divalent cations had different effects on the phosphatase activity of both strains. Mg2+ and Mn2+ enhanced the phosphatase activity from Choachi strain, 2 and 5 fold, respectively, but not from SC58 strain. Zinc, cooper and cobalt ions, enhanced phosphatase activity from SC-58 strain 3, 4 and 5-fold, respectively. However no effect was observed on phosphatase activity from Choachi. The acid phosphatase inhibitors ammonium molybdate, sodium fluoride and sodium ortovanadate, also a phosphotyrosine phosphatase inhibitor, inhibited the enzymatic activity expressed by the two strains of T. rangeli. Inorganic phosphate, a natural product of reactions catalyzed by phosphatases, inhibited ecto-phosphatase activity from Choachi but not from SC58. The observed differences could be attributed to a intraspecific variability or by the different origins of the strains since several biological, biochemical, immunological and molecular markers revealed that SC-58, isolated from a rodent (Echimys dasytrix) in southern Brazil, and Choachi, isolated from a triatomine bug (Rhodnius prolixus) in Colômbia, are polar strains of the parasite. Further studies are in progress including distinct strains.
Supported by CNPq, CAPES and FAPERJ.
|