Non-invasive DNA transfection of B. glabrata using polyethylenimine (PEI)

– Ampicillin (Amp)
– 0.2 mg/ml of plasmid DNA (pDNA)
– PEI transfection reagent
– Sterile distilled water

Day 1: Treat snail(s) with 100 mg/ml Amp in distilled water (DW) overnight
Day 2: DNA/PEI complex preparation (N/P ratio* = 6) transfection (Knight et al., 2011)

  • Dilute one microgram of plasmid DNA in 0.5 ml of nuclease free water and vortex briefly. Keep the tube at room temperature (RT)
  • Dilute 0.78 ml** of PEI solution in 0.5 ml of nuclease free water and vortex briefly
  • Add diluted PEI solution in to pDNA solution slowly and vortex. Let the complex forming at RT for 15 min
  • Transfection: transfer the clean-dry snail from day 1 into the DNA/PEI complex mixture and let it culture for at least 24 hours
  • Monitor the successful of transfection by several assay e.g. PCR with specific primer to the plasmid DNA or your gene of interest.

Note: This protocol is for 1 snail transfection (1 snail per 1 ml final DNA/PEI mixture).

* N/P ratio is a measure of the ionic balance within the complexes and is defined as the number of nitrogen residues of PEI per nucleic acid phosphate. For the parasite transfection, the suggested N/P ratio is between 8-11 (Liang S. Knight M and Jolly, 2013, Liang et al., 2014).

** This volume would be changed according to the various N/P ratios

1. Knight M, Miller A, Lui Y, Scaria P, Woodle M, Ittiprasert W. Polyethyleneimine (PEI) mediated siRNA gene silencing in the Schistosoma mansoni snail host, Biomphalaria glabrata. PLoS Negl Trop Dis 2011: 5(7): e1212.
2. Liang S, Knight M, Jolly ER. Polyethyleneimine mediated DNA transfection in schistosome parasites and regulation of the WNT signaling pathway by a dominant-negative SmMef 2. PLoS Negl Trop Dis 2013: 7(7): e2332.
3. Liang S, Varrecchia M, Ishida K, Jolly ER. Evaluation of schistosome promoter expression for transgenesis and genetic analysis. PLoS One 2014: 9(5): e98302.

For more information, contact André Miller at