Team:Paris Bettencourt/Notebook/Trojan Horse/Tuesday 23rd July.html


Trojan Horse

23th July

Infectiveness characterization experiments
  • The night before: prepare O/N of F+ cells, prepare O/N of phagemid producing cells (in this case : sT007 )
  • Centrifugate phagemid producing cells
  • Filter the supernatant 0.45um, stock it at 4°C (it contains the phages)
  • Dilute 200x MGZ1, F+ from O/N
  • Wait until OD600 = 0.7
  • Immediately mix MGZ1 and the supernatant in different proportions

Here we tried 1/1 (vol supernatant/vol cells), 1/10 and 1/100
    Immediately dilute each of them to 10-3, 10-4, 10-5, 10-6
  • Plate 100uL of those dilutions on LB-agar, AMP, KAN, AMP+KAN
  • Incubate O/N
  • Count colonies
  • Interpretation: Colonies on AMP: infected by litmus28i
    Colonies on KAN: infected by M13K07
    Colonies on AMP+KAN: coinfected by litmus28i and M13K07 phagemid producing cells


  • Cells that were mixed with 1/1 supernatant didn't survive the excess of antibiotics that were present in the supernatant.
  • Even at low ratio like 1/100 the infection rate of litmus28i-GFP is about 100%. GFP detection confirmed this result: almost 100% of cells were fluorescent.
  • Co-infection did occur. It would be interesting to test if those colonies are indeed producing phages.

Start O/N culture of M13K07 Start O/N culture of MGZ1,F+