Aspartic proteases are important virulence factors for pathogens and are recognized as attractive drug targets. Seven aspartic proteases (ASPs) have been identified in Toxoplasma gondii genome. Bioinformatics and phylogenetic analyses regroup them into five monophyletic groups. Among them, TgASP1, a coccidian specific aspartic protease related to the food vacuole plasmepsins, is associated with...

Toxoplasmosis and leishmaniasis are two worldwide zoonoses caused by the protozoan parasites Toxoplasma gondii and Leishmania spp., respectively. This report describes the clinical and laboratorial findings of a co-infection with both parasites in a 4-year-old female dog suspected of ehrlichiosis that presented anemia, thrombocytopenia, hypoalbuminemia, hyperglobulinemia, tachyzoite-like struct...

Mycoplasmas are common contaminants of eukaryotic cells grown in tissue culture. A commercially available Mycoplasma Removal Agent (MRA) was therefore assessed for its effect on tachyzoites of Neospora caninum, in order to determine its suitability for further use in parasite cell cultures. Analyses of tachyzoite and excreted-secreted proteins and antigens by SDS-PAGE and Western blotting show ...

The invasive stages of Apicomplexa parasites, called zoites, have been largely studied in in vitro systems, with a special emphasis on their unique gliding and host cell invasive capacities. In contrast, the means by which these parasites reach their destination in their hosts are still poorly understood. We summarize here our current understanding of the cellular basis of in vivo parasitism by...

Ultrathin sections of tissue cysts isolated from the brain of Toxoplasma gondii infected mice were submitted to two different methodologies derived from the periodic acid - Schiff's reagent (PAS) technique. The use of osmium tetroxide vapor as a developing agent of the aldehyde oxidation to reveal polysaccharides with periodic acid resulted in positive reaction in amylopectin granules in bradyz...

Histone H2Ba of Toxoplasma gondii was expressed as recombinant protein (rH2Ba) and used to generate antibody in mouse that is highly specific. Antibody recognizing rH2Ba detects a single band in tachyzoite lysate of the expected molecular weight (12kDa). By indirect immunofluorescence (IFA) in in vitro grown tachyzoites and bradyzoites, the signal was detected only in the parasite nucleus. The ...

neospora caninum is a coccidian protozoan parasite which is a major cause of bovine abortions and neonatal mortality in cattle, sheep, goat and horse. occasionally, cultured cells are used for isolation and multiplication of the agent in vitro with several purposes. in this study the tachyzoite yields of n. caninum were compared in various cell cultures as the host cell lines. among the cell cu...

Toxoplasma gondii (T. gondii) is a protozoan parasite that infects a wide range of intermediate hosts, including all mammals and birds. Up to 20% of the human population in the US and 30% in the world are chronically infected. This paper presents a mathematical model to describe intra-host dynamics of T. gondii infection. The model considers the invasion process, egress kinetics, interconversio...

By using stage-specific monoclonal antibodies, an in vitro model has been developed to analyze the kinetics of expression of stage-specific antigens during the conversion process between tachyzoites and bradyzoites of Toxoplasma gondii. Following infection of murine macrophages with bradyzoites, the expression of bradyzoite-specific antigens declined, whereas the expression of tachyzoite-specif...