RESUMEN
Perkinsus protozoan parasites have been associated with high mortality of bivalves worldwide, including Brazil. The use of antiproliferative drugs to treat the Perkinsosis is an unusual prophylactic strategy. However, because of their environment impact it could be used to control parasite proliferation in closed system, such as hatchery. This study evaluated the anti-Perkinsus activity potential of synthesized and commercial compounds. Viability of hypnospores of Perkinsus spp. was assessed in vitro. Cells were incubated with three 2-amino-thiophene (6AMD, 6CN, 5CN) and one acylhydrazone derivatives (AMZ-DCL), at the concentrations of 31.25; 62.5; 125; 250 and 500⯵M and one commercial chlorinated phenoxy phenol derivative, triclosan (2, 5, 10 and 20⯵M), for 24-48â¯h. Two synthetic molecules (6CN and AMZ-DCL) caused a significant decline (38 and 39%, respectively) in hypnospores viability, at the highest concentration (500⯵M), after 48â¯h. Triclosan was the most cytotoxic compound, causing 100% of mortality at 20⯵M after 24â¯h and at 10⯵M after 48â¯h. Cytotoxic effects of the compounds 6CN, AMZ-DCL, and triclosan were investigated by measuring parasite's zoosporulation, morphological changes and metabolic activities (esterase activity, production of reactive oxygen species and lipid content). Results showed that zoosporulation occurred in few cell. Triclosan caused changes in the morphology of hypnospores. The 6CN and AMZ-DCL did not alter the metabolic activities studied whilst Triclosan significantly increased the production of reactive oxygen species and changed the amount and distribution of lipids in the hypnospores. These results suggest that three compounds had potential to be used as antiprotozoal drugs, although further investigation of their mechanism of action must be enlightened.
Asunto(s)
Alveolados/efectos de los fármacos , Antiprotozoarios/farmacología , Ostreidae/parasitología , Alveolados/patogenicidad , Alveolados/fisiología , Análisis de Varianza , Animales , Antiprotozoarios/uso terapéutico , Acuicultura , Bivalvos/parasitología , Brasil , Carboxilesterasa/efectos de los fármacos , Carboxilesterasa/metabolismo , Estuarios , Proteínas Fluorescentes Verdes , Hidrazonas/química , Hidrazonas/farmacología , Metabolismo de los Lípidos/efectos de los fármacos , Sustancias Luminiscentes , Especies Reactivas de Oxígeno/metabolismo , Agua de Mar , Esporas Protozoarias/efectos de los fármacos , Tiofenos/química , Tiofenos/farmacología , Triclosán/farmacologíaRESUMEN
Calcium has an important role on signaling of different cellular processes, including growth and differentiation. Signaling by calcium also has an essential function in pathogenesis and differentiation of the protozoan parasites Entamoeba histolytica and Entamoeba invadens. However, the proteins of these parasites that regulate the cytoplasmic concentration of this ion are poorly studied. In eukaryotic cells, the calcium-ATPase of the SERCA type plays an important role in calcium homeostasis by catalyzing the active efflux of calcium from cytoplasm to endoplasmic reticulum. Here, we reported the identification of SERCA of E. invadens (EiSERCA). This protein contains a putative sequence for endoplasmic reticulum retention and all domains involved in calcium transport identified in mammalian SERCA. By immunofluorescence assays, an antibody against SERCA of E. histolytica detected EiSERCA in a vesicular network in the cytoplasm of E. invadens trophozoites, co-localizing with calreticulin. Interestingly, EiSERCA was redistributed close to plasma membrane during encystation, suggesting that this pump could participate in regulate the calcium concentration during this process. In addition, thapsigargin and cyclopiazonic acid, both specific inhibitors of SERCA, affected the number and structure of cysts, supporting the hypothesis that calcium flux mediated by SERCA has an important role in the life cycle of Entamoeba.
Asunto(s)
ATPasas Transportadoras de Calcio/antagonistas & inhibidores , Entamoeba/efectos de los fármacos , Entamoeba/crecimiento & desarrollo , Proteínas Protozoarias/antagonistas & inhibidores , Esporas Protozoarias/efectos de los fármacos , Esporas Protozoarias/crecimiento & desarrollo , ATPasas Transportadoras de Calcio/análisis , ATPasas Transportadoras de Calcio/genética , Calreticulina/análisis , Inhibidores Enzimáticos/metabolismo , Indoles/metabolismo , Microscopía Confocal , Microscopía Fluorescente , Proteínas Protozoarias/análisis , Proteínas Protozoarias/genética , Tapsigargina/metabolismo , Vesículas Transportadoras/químicaRESUMEN
The sporontocidal activity of three steroids (SN-1, SN-2 and SN-4) from Solanum nudum Dunal (Solanaceae) was determined against naturally circulating isolates of Plasmodium vivax in Anopheles albimanus. Laboratory-reared Anopheles albimanus mosquitoes were infected with P. vivax from gametocytemic blood of volunteers resident in Buenaventura, Valle del Cauca (Colombian Pacific Coast) by using an artificial membrane feeder. Prior to mosquito feeding, gametocytemic blood was centrifuged, plasma was separated, packed blood red cells were washed with RPMI 1640 and then resuspended in non-immune AB serum, then the steroids were added at different doses. On day 7 after infection, the presence and number of oocysts in mosquitoes was determined. The steroid SN-2 reduced the infection of mosquitoes by 90% and the mean number of oocysts by 60%. These data confirmed that the experimental steroid is capable of interrupting the sporogonic development of P. vivax in Anopheles albimanus. This experimental steroid has potential for transmission blocking in vivax malaria.