Anaerobic ATP synthesis pathways and inorganic phosphate transport and their possible roles in encystment in Acanthamoeba castellanii.

Acanthamoeba castellanii is the etiological agent of amoebic keratitis and is present in the environment in trophozoite or cyst forms. Both forms can infect the vertebrate host and colonize different tissues. The high resistance of cysts to standard drugs used in clinics contributes to the lack of effective treatments.

E-NTPDases: Possible Roles on Host-Parasite Interactions and Therapeutic Opportunities.

Belonging to the GDA1/CD39 protein superfamily, nucleoside triphosphate diphosphohydrolases (NTPDases) catalyze the hydrolysis of ATP and ADP to the monophosphate form (AMP) and inorganic phosphate (Pi). Several NTPDase isoforms have been described in different cells, from pathogenic organisms to animals and plants. Biochemical characterization of nucleotidases/NTPDases has revealed the existence of isoforms with different specificities regarding divalent cations (such as calcium and magnesium) and substrates.

3-Bromopyruvate: A new strategy for inhibition of glycolytic enzymes in Leishmania amazonensis.

The compound 3-bromopyruvate (3-BrPA) is well-known and studies from several researchers have demonstrated its involvement in tumorigenesis. It is an analogue of pyruvic acid that inhibits ATP synthesis by inhibiting enzymes from the glycolytic pathway and oxidative phosphorylation. In this work, we investigated the effect of 3-BrPA on energy metabolism of L.

Differential regulation of E-NTPdases during Leishmania amazonensis lifecycle and effect of their overexpression on parasite infectivity and virulence.

Infections caused by Leishmania amazonensis are characterized by a persistent parasitemia due to the ability of the parasite to modulate the immune response of macrophages. It has been proposed that ecto-nucleoside triphosphate diphosphohydrolase (E-NTPDases) could be able to suppress the host immune defense by reducing the ATP and ADP levels. The AMP generated from E-NTPDase activity can be subsequently hydrolyzed by ecto-nucleotidases, increasing the levels of adenosine, which can reduce the inflammatory response.

Leishmania amazonensis inorganic phosphate transporter system is increased in the proliferative forms.

Here we characterize a high-affinity Pi transport system energized by a H gradient in Leishmania amazonensis. P uptake and transcription of LamPho84 gene are differentially regulated during parasite life cycle. Our data suggest that P acquisition could be a pivotal task for the success of the parasite throughout its life cycle.

NTPDase activities: possible roles on Leishmania spp infectivity and virulence.

Nucleoside triphosphate diphosphohydrolases (NTPDases) are enzymes that belong to the GDA1/CD39 protein superfamily. These enzymes catalyze the hydrolysis of ATP and ADP to the monophosphate form (AMP). Biochemical characterization of the nucleotidases/NTPDases from various types of cells, including those from plants, animals, and pathogenic organisms, has revealed the existence of several isoforms with different specificities with respect to divalent cations (magnesium, calcium, manganese, and zinc) and substrates.

The biochemical characterization of two phosphate transport systems in Phytomonas serpens.

Inorganic phosphate (P) is an essential nutrient for all organisms because it is required for a variety of biochemical processes, such as signal transduction and the synthesis of phosphate-containing biomolecules. Assays of P uptake performed in the absence or in the presence of Na indicated the existence of a Na-dependent and a Na-independent P transporter in Phytomonas serpens. Phylogenetic analysis of two hypothetical protein sequences of Phytomonas (EM1) showed similarities to the high-affinity P transporters of Saccharomyces cerevisiae: Pho84, a Na-independent P transporter, and Pho89, a Na-dependent P transporter.