Intrinsic fluctuations of cell migration under different cellular densities

The motility of the Dictyostelium discoideum (DD) cell is studied by video microscopy when the cells are plated on top of an agar plate at different densities, n. It is found that the fluctuating kinetics of the cells can be divided into two normal directions: the cell's forward-moving direction and its normal direction. Along the forward-moving direction, the slope of the amplitude of fluctuation vs. velocity (R_⊥(v)) increases with n, while along the normal direction the slope of R is independent of n. Both R _⊥ and R are functions of the cell speed v. The observed linearity in R(v) indicated that the amplitude of orientational fluctuation (κ) of DD cells is a constant independent of v. The independence of the slope of R(v) on n indicated that κ is also not affected by cellular interactions. The independence of κ on both v and n suggests that orientational fluctuation originates from the intrinsic property of motion fluctuations in DD. This journal is