Behaviour of the cell surface during movement of preaggregation cells of the slime mould dictyostelium Discoideum studied with fluorescent antibody

Although several theories relating to the mechanical behaviour of cell surface during movement have been put forward, a division into two groups can be made according to whether the surface is thought to turn over rapidly or to be a relatively permanent structure. In order to determine whether turnover of the surface membrane plays an important role in the locomotion of preaggregation cells of Dictyostehum discoideum, their surface was labelled with fluorescent antibody. The cell surface remains labelled during movement though there is an initial accumulation of fluorescence at the tail. There is little fluorescent labelling of the internal contents. The results are interpreted as showing that surface turnover is not an essential feature of cell movement.