Remarks on the Motility and Thermotactic Response of Fibroblasts

Abstract

The motion of mouse L cells (fibroblast) in vitro is studied by means of time-lapse photography. In particular, the response of the cells to a temperature gradient of7· 22°Ccm-1 is studied for several temperatures from 32· 6°C to 39· 7°C. Three measures of the thermotactic response are used: (1) the motility, defined in terms of the mean-square displacement of an ensemble of cells, (2) the displacement of the centre of gravity of an ensemble of cells versus time, and (3) the distribution in the number of cells in an ensemble moving up the gradient compared with the number moving down the gradient. There is no evidence of a thermotactic response as determined by these three measures. The variance in the data can be understood in terms of statistical fluctuations.