Fig. 4

Re-immobilization of ADP1 (pAtaA) cells. a Repetition of the immobilization/detachment cycle of ADP1 (pAtaA) cells. The cells were immobilized onto well surfaces of a PS plate in 100 mM KCl solution for 2 h, detached by washing with dH₂O from the PS plate, collected by centrifugation, resuspended in the KCl solution, added to fresh wells, and incubated for re-immobilization for 2 h. Immobilized cells were visualized and quantified by crystal violet staining. This process was repeated four times. Photographs indicate the stained cells immobilized on the surface at each cycle. b AtaA molecules on the ADP1 (pAtaA) cell surface before and after the repetition of the immobilization/detachment cycle were analyzed by flow cytometry. The black and red lines show surface-displayed AtaA before the first immobilization and after the fourth cycle of the repetition, respectively. The wild type of ADP1 without AtaA molecules was subjected to the same analysis as a negative control. c Esterase activities of ADP1 (pAtaA) cells immobilized on the plate wells in a. d Time course of the immobilization ratio of ADP1 (pAtaA) cells onto the polyurethane support in each immobilization/detachment cycle. In the respective cycles, the cells were immobilized onto polyurethane foam in 100 mM KCl solution in a flask with shaking and the immobilization ratio was calculated from a decrease in the OD₆₆₀ of the cell suspension. Data are expressed as mean ± SEM (n = 3). n.s. not significant (ANOVA, P > 0.1)