TABLE 1.

Effect of spermidine addition to the medium on the level of polyamines in cellsa

StrainTime of incubation (h)Addition of 2 mM spermidinePolyamine concn (mM)
PutrescineSpermidine
CAG2242/pUC119124.86 ± 1.125.27 ± 0.88
12+0.19 ± 0.1426.2 ± 2.34
243.03 ± 1.145.73 ± 1.04
24+0.17 ± 0.1030.9 ± 2.28
361.66 ± 0.164.58 ± 0.58
36+0.07 ± 0.0432.3 ± 3.06
CAG2242/pUCmdtJI120.96 ± 0.525.95 ± 1.42
12+0.15 ± 0.1411.8 ± 0.66
243.40 ± 1.264.71 ± 1.06
24+0.24 ± 0.1012.1 ± 2.06
363.92 ± 0.462.83 ± 1.00
36+0.33 ± 0.2615.5 ± 1.34
  • a E. coli CAG2242/pUC119 and CAG2242/pUCmdtJI cells were cultured in the presence and absence of 2 mM spermidine for the indicated times, and the polyamine content in cells was measured as described in Materials and Methods. The concentrations of polyamines were calculated based on the data for 5 μl of cell volume per mg protein (19, 29). Values are means ± SD for three samples.