Paris/July 7


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Growth kinetics of w121 strain

We make an array to test growth of w121 on different growth media (LB, S0.2, S0.4, S0.6, S0.8), supplemented with different amounts of DAP.

Two questions are addressed by the following assay:

  • What is the growth behaviour of w121 (dapA- strain) at different concentrations of DAP?
  • How does w121 strain grow on filtrates of MG1655 growth medium; that is, does MG1655 secrete DAP during growth?

MG1655 was grown on LB medium and the growth medium was filtered free of bacteria at different DO (Optical Densities) during exponential growth phase:

S0.2 (at DO=0.2) S0.4 (at DO=0.4) S0.6 etc S0.8

W121 was grown on different media:

LB line B in the array S0.2 (at DO=0.2) line C in the array S0.4 line D in the array S0.6 line E in the array S0.8 line F in the array

In the different columns, DAP was added to the indicated final concentrations (without taking into account DAP produced by MG1655 regarding the recycled growth media)

Kinetic Array :w121 kinetic as a function of DAP and supplemented medium (S0.x)
1 2 3 4 5 6 7 8 9 10 11 12
A H20 H20 H20 H20 H20 H20 H20 H20 H20 H20 H20
B H20 LB+0µM DAP LB+25µM DAP LB+37.5µM DAP LB+50µM DAP LB+62.5µM DAP LB+75µM DAP LB+100µM DAP LB+300µM DAP LB+0µM DAP H20
C H20 S0.2+0µM DAP S0.2+25µM DAP S0.2+37.5µM DAP S0.2+50µM DAP S0.2+62.5µM DAP S0.2+75µM DAP S0.2+100µM DAP S0.2+300µM DAP S0.2+0µM DAP H20
D H20 S0.4+0µM DAP S0.4+25µM DAP S0.4+37.5µM DAP S0.4+50µM DAP S0.4+62.5µM DAP S0.4+75µM DAP S0.4+100µM DAP S0.4+300µM DAP S0.4+0µM DAP H20
E H20 S0.6+0µM DAP S0.6+25µM DAP S0.6+37.5µM DAP S0.6+50µM DAP S0.6+62.5µM DAP S0.6+75µM DAP S0.6+100µM DAP S0.6+300µM DAP S0.6+0µM DAP H20
F H20 S0.8+0µM DAP S0.8+25µM DAP S0.8+37.5µM DAP S0.8+50µM DAP S0.8+62.5µM DAP S0.8+75µM DAP S0.8+100µM DAP S0.8+300µM DAP S0.8+0µM DAP H20
G H20 H20 H20 H20 H20 H20 H20 H20 H20 H20 H20

See results.

The 96 well plate is surrounded by H2O in order to maintain humidity during the assay. In each slot, 200µL of the growth medium (LB or S0.x) is mixed with 2µL of w121 culture grown ON, and with different amount of DAP (see table). The growth profile is measured over a period of 10H, a DO measurement is acquired each 3min.