サルモネラ菌の走化性強さの観察と数理モデルによる推定

抄録

Bacterial cells exhibit chemotaxis by repeating straight swimming (run) and an abrupt change of the swimming direction (tumble). Cells can detect the change in the concentration of a chemical attractant during the run and decrease the frequency of the tumbles if the cells have swum toward the favorable direction. As for the chemotaxis mechanism, a mathematical model has been proposed where the frequency of the tumble is correlated with the chemotaxis intensity. In this study, we observe the chemotaxis of bacterial cells to compare the measurement with the mathematical model. Salmonella typhimurium cells accumulating around a chemical attractant (1 M L-serine) were observed. The frequency of the tumbles decreases when the cell swims toward the attractant. The density distribution of the cell number has an exponential decay with the distance from the source of an attractant, which has been predicted by the mathematical model.