Alladi Ramakrishnan Hall

Effect of extra-cellular nutrient environment and intra-cellular biochemical conditions on the chemotactic performance of E. coli

Subrata Dev

SNBNCBS, Kolkata

Chemotaxis is the directed motion of organisms in response to a chemical gradient. E.coli chemotaxis is one of the most well-studied systems in biology. The motion of an E. coli consists of run-and-tumble modes. In presence of nutrient bacteria accumulate in the region of higher concentrations by modulating its run durations. We are interested in two broad questions. The first one is related to
chemotactic performance of an E. coli cell and the second one is related to its run- and-tumble motion.We identify a set of well-defined response functions which characterize different aspects of chemotactic performance and investigate how these different response functions depend on the external environment and the internal biochemical pathway
of the E. coli cell and at what conditions the chemotactic performance becomes most
efficient. The second question deals with a simple run-and-tumble random walk
whose switching frequencies between run and tumble mode depend on a stochastic
signal. We are interested in characterizing the effect of signaling noise on the long-
time behavior of the random walker and investigate how the fluctuations present in
the input signal affect the motion.