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Determination of the viability of Toxoplasma gondii oocysts by PCR real-time after treatment with propidium monoazide.

Maria Aparecida Moraes MarcianoRafaela Aparecida SilvaMaria Luisa BarbosaAntônio Roberto Souza FerreiraVera Lucia Pereira-Chioccola
Published in: Revista do Instituto de Medicina Tropical de Sao Paulo (2020)
This study aimed to investigate a methodology for discriminating viable and non-viable T. gondii oocysts in water. Analyses included two steps: (i) microscopic investigation with vital dyes; (ii) molecular investigation, using a real time PCR (qPCR), after parasite treatment (or not) with propidium monoazide (PMA). The method was called qPCR-PMA. Oocyst aliquots were incubated (15 min) at 25 ºC or 100 ºC and analyzed by microscopy, after trypan blue and neutral red staining. Microscopic investigation determined viable and non-viable oocysts. For the molecular investigation, both aliquots of oocysts were treated with PMA. Non-viable oocysts, after PMA treatment, exhibited an inhibition of DNA amplification by qPCR. Although analyses were carried out with oocysts treated experimentally, these results suggest that qPCR-PMA can be a useful strategy to distinguish viable and non-viable T. gondii oocysts in water safety testing, showing if water is safe to drink.
Keyphrases
  • toxoplasma gondii
  • single molecule
  • real time pcr
  • high throughput
  • optical coherence tomography
  • newly diagnosed
  • circulating tumor cells
  • flow cytometry
  • liquid chromatography