ClyA protein levels in derivatives of ExPEC strain IHE3034. (A) Effect of the sfaX-Y genes on the relative levels of ClyA protein. Samples were taken from cultures grown in LB medium at 37C of the following strains: lane 1, IHE3034 (sfaX
+); lane 2, AES1 (sfaX::kan); lane 3, AES153 (Δ sfaY); lane 4, IHE3034/pYMZ81; lane 5, AES1/pYMZ81; lane 6, AES153/pYMZ81; lane 7, IHE3034/pUC18; lane 8, AES1/pUC18; lane 9, AES153/pUC18. The immunoreactive bands corresponding to ClyA and the plasmid encoded β - Lactamase (used as the control in this experiment) are indicated with arrowheads. (B) Quantification of relative ClyA levels in the strains IHE3034/pYMZ81 and AES1/pYMZ81 calculated from the ratios of ClyA and β Lactamase levels as monitored in the image analyzer (see Methods). The data represent the average value of three independent experiments and vertical bars indicate the standard deviations. An asterik indicates significance in difference according to Student'st-test.