Effects Of Fructose On Chemotaxis And Motility Of E.coli

Organism,as little as bacteria,can respond to the change in the external environment they live in the nature,which is the basis of biological phenomena.These responses are accomplished by the single cells that consist these creatures,through their intracellular signal networks that react to the outer environment change.We take the behavior of bacteria as an example,and Escherichia coli was selected as the model organism.We use molecular biology techniques and statistical physical models to study the behavior of molecules and cells from the perspective of flagellar motors.Fructose is an isomer of glucose.Choline is a semi-essential nutrient for humans.Apart from obtaining choline as part of the macromolecule phosphatidylcholine(PC),the body cannot produce choline through other means.Here,we used microfluidic and bead assay to characterize the chemotaxis and motility behavior of E.coli to different concentrations of fructose from 0 m M to 50 m M,and to different concentrations of choline,and the effect of fructose on the accumulation of E.coli on surface.Based on the above considerations,we will systematically study changes in bacterial motor behavior and changes in chemotactic systems by adding different nutritional factors.The main findings of this paper are as follows:(1)Adding nutritional factors such as fructose and choline can promote the growth of E.coli,whether it is wild-type or gene-deficient,and the effect was more significant as the concentration increases.When the concentration was higher than 5m M,the growth promotion effect did not continue to enhance.(2)Fructose can affect the movement of wild-type E.coli and significantly reduced the CCW rotation speed which can promote the aggregation of cells on the surface.Moreover,CCW rotation speed decreased significantly at concentrations of 0.1m M,1m M and 10 m M.But it had no effect on CW rotation speed.On the other hand,fructose increased CW bias.The above phenomenon was not found in the gene-deficient strains.(3)The wild-type cells responded to the stimulation of fructose,which indicated that fructose was an attractant to E.coli,while the cells defective in chemotaxis,JY27/pKAF131,HCB429/pKAF131,and HCB316/p FD313,could not sense the stimulus of fructose.