Improved negative selection protocol for Plasmodium berghei in the rodent malarial model.

Area of Science:

• Malariology
• Parasitology
• Molecular Biology

Background:

• Transgenic Plasmodium berghei lines are crucial for malaria research.
• Traditional selection methods often involve intraperitoneal injection of drugs, which is labor-intensive and requires significant animal handling.
• The yFCU negative selectable marker system, combining yeast cytosine deaminase and uridyl phosphoribosyl transferase (UPRT), offers a promising avenue for parasite selection.

Purpose of the Study:

• To present an improved methodology for selecting transgenic Plasmodium berghei lines.
• To evaluate the efficacy of administering the selection drug 5-fluorocytosine (5FC) via drinking water instead of intraperitoneal injection.
• To assess the impact of the improved methodology on animal welfare, specifically addressing refinement and reduction principles.

Main Methods:

• Development of transgenic Plasmodium berghei lines expressing the yFCU negative selectable marker.
• Administration of 5-fluorocytosine (5FC) through the drinking water of infected mice.
• Comparison of the new method with traditional intraperitoneal injection for selection efficacy.

Main Results:

• The improved methodology using 5FC in drinking water is as effective as intraperitoneal injection for selecting transgenic Plasmodium berghei.
• The new method significantly reduces labor, animal handling, and the number of animals required for selection.
• The findings align with the principles of refinement and reduction in animal experimentation.

Conclusions:

• Administering 5-fluorocytosine via drinking water is a viable and effective alternative to intraperitoneal injection for selecting transgenic Plasmodium berghei.
• This improved methodology enhances animal welfare by reducing handling and the number of animals needed.
• The study provides a more humane and efficient approach to generating transgenic Plasmodium berghei parasite lines for research.