The apicomplexans are a group of obligate animal pathogens that include Plasmodium (malaria), Toxoplasma (toxoplasmosis), and Cryptosporidium (cryptosporidiosis) [1]. They are an extremely diverse and specious group but are nevertheless united by a distinctive suite of cytoskeletal and secretory structures related to infection, called the apical complex, which is used to recognize and gain entry into animal host cells. The apicomplexans are also known to have evolved from free-living photosynthetic ancestors and retain a relict plastid (the apicoplast), which is non-photosynthetic but houses a number of other essential metabolic pathways [2]. Their closest relatives include a mix of both photosynthetic algae (chromerids) and non-photosynthetic microbial predators (colpodellids) [3]. Genomic analyses of these free-living relatives have revealed a great deal about how the alga-parasite transition may have taken place, as well as origins of parasitism more generally [4]. Here, we show that, despite the surprisingly complex origin of apicomplexans from algae, this transition actually occurred at least three times independently. Using single-cell genomics and transcriptomics from diverse uncultivated parasites, we find that two genera previously classified within the Apicomplexa, Piridium and Platyproteum, form separately branching lineages in phylogenomic analyses. Both retain cryptic plastids with genomic and metabolic features convergent with apicomplexans. These findings suggest a predilection in this lineage for both the convergent loss of photosynthesis and transition to parasitism, resulting in multiple lineages of superficially similar animal parasites.

• MeSH
• Apicomplexa klasifikace   MeSH
• apikoplasty klasifikace   MeSH
• biologická evoluce * MeSH
• fylogeneze MeSH
• paraziti klasifikace   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Toxoplasma gondii, an etiologic agent of toxoplasmosis, is an obligate intracellular parasite, which exhibits an apicoplast organelle which assists in the metabolism of isoprenoids and other pivotal mediators for the parasite survival. Statins are drugs that inhibit cholesterol synthesis, blocking the conversion of the substrate HMG-CoA to mevalonate, thus preventing the initial processes of the biosynthesis of these precursors, both in humans and parasite. In the light of this information, we determined the effect of pravastatin and simvastatin associated with the current drugs (pyrimethamine and sulfadiazine) as a possible alternative treatment for this infection. Cytotoxicity was evaluated in HeLa cells by MTT assay, which was observed the drug combinations did not affect cell viability. HeLa cells (105) were infected with T. gondii tachyzoites of RH strain (5 × 105) and treated with pravastatin and/or simvastatin combined with pyrimethamine and/or sulfadiazine for 24 h. Our data showed a significant reduction in cell adhesion, infection and mainly parasite proliferation in all treatments. Based on these results, the combination of statins with drugs used in current therapy showed to be a promising therapeutic alternative for toxoplasmosis treatment.

• MeSH
• antiprotozoální látky aplikace a dávkování   farmakologie   MeSH
• apikoplasty účinky léků   MeSH
• HeLa buňky MeSH
• kombinovaná farmakoterapie metody   MeSH
• proliferace buněk účinky léků   MeSH
• pyrimethamin aplikace a dávkování   MeSH
• statiny aplikace a dávkování   farmakologie   MeSH
• sulfadiazin aplikace a dávkování   MeSH
• synergismus léků MeSH
• techniky in vitro MeSH
• Toxoplasma * růst a vývoj   účinky léků   MeSH
• toxoplazmóza farmakoterapie   MeSH
• Publikační typ
• práce podpořená grantem MeSH

• MeSH
• antigeny protozoální chemie   genetika   metabolismus   MeSH
• Apicomplexa imunologie   fyziologie   MeSH
• apikoplasty imunologie   fyziologie   MeSH
• biologická adaptace MeSH
• biologická evoluce MeSH
• druhová specificita MeSH
• extracelulární prostor imunologie   metabolismus   parazitologie   MeSH
• interakce hostitele a parazita * MeSH
• lidé MeSH
• membránové proteiny chemie   genetika   metabolismus   MeSH
• protozoální infekce zvířat imunologie   metabolismus   parazitologie   MeSH
• protozoální infekce imunologie   metabolismus   parazitologie   MeSH
• protozoální proteiny chemie   genetika   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH

Chromerida are algae possessing a complex plastid surrounded by four membranes. Although isolated originally from stony corals in Australia, they seem to be globally distributed. According to their molecular phylogeny, morphology, ultrastructure, structure of organellar genomes, and noncanonical pathway for tetrapyrrole synthesis, these algae are thought to be the closest known phototrophic relatives to apicomplexan parasites. Here, we summarize the current knowledge of cell biology and evolution of this novel group of algae, which contains only two formally described species, but is apparently highly diverse and virtually ubiquitous in marine environments.

• MeSH
• Apicomplexa cytologie   metabolismus   MeSH
• apikoplasty parazitologie   MeSH
• biologie buňky MeSH
• lidé MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH