Trypanosoma rangeli: differential expression of ecto-phosphatase activities in response to inorganic phosphate starvation.
In this work, we showed that living cells of Trypanosoma rangeli express different ecto-phosphatase activities in response to different inorganic phosphate (Pi) concentrations in the culture medium. The ecto-phosphatase activity from T. rangeli grown at low-Pi concentration was inhibited by the increase of the pH, while the ecto-phosphatase of the cells grown at high Pi concentration was not modulated by the change of the pH of the medium. Okadaic acid inhibited only the ecto-phosphatase activity from cells grown at low-Pi concentration but not the ecto-phosphatase activity from cells grown at high-Pi concentration. Accordingly, phosphatase activity from T. rangeli grown at low Pi concentration was able to hydrolyze P-serine and P-threonine at high rate but not P-tyrosine. The phosphatase activity from T. rangeli grown at high-Pi concentration was able to hydrolyze P-serine, P-threonine and P-tyrosine with the same rate. The addition of anterior midgut homogenate of Rhodnius prolixus on the epimastigotes suspension inhibited the enzyme activity of T. rangeli grown at low-Pi concentration. On the other hand, anterior midgut homogenate had no effect in the ecto-phosphatase of T. rangeli maintained at high-Pi concentration. Altogether, the results described here indicate that ecto-phosphatase activities hydrolyzing phosphorylated compounds present in the extracellular medium of T. rangeli are regulated by the external Pi concentration.
Dick
Claudia Fernanda
CF
Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, UFRJ, Cidade Universitária, Ilha do Fundão, 21941-590 Rio de Janeiro, RJ, Brazil.
Dos-Santos
André Luiz Araújo
AL
Fonseca-de-Souza
André L
AL
Rocha-Ferreira
Juliana
J
Meyer-Fernandes
José Roberto
JR
D000818:Animals; D003470:Culture Media; D006801:Humans; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D007303:Insect Vectors / Q000469:parasitology; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D009596:Nitrophenols / Q000378:metabolism; D009943:Organophosphorus Compounds / Q000378:metabolism; D010710:Phosphates / Q000378:metabolism*; D010744:Phosphoric Monoester Hydrolases / Q000378:metabolism*; D012239:Rhodnius / Q000469:parasitology; D014345:Trypanosoma / Q000201:enzymology*
D003470:Culture Media; D009596:Nitrophenols; D009943:Organophosphorus Compounds; D010710:Phosphates; C008644:nitrophenylphosphate; D007770:L-Lactate Dehydrogenase; D010744:Phosphoric Monoester Hydrolases