Use of aqueous two-phase partition to detect cell surface changes during growth of Dictyostelium discoideum.

Changes in the cell surface properties of amoebae of Dictyostelium discoideum during growth in different culture conditions have been studied by aqueous two-phase partitioning on a thin-layer countercurrent distribution apparatus. Changes in cell surface properties were not dependent on the source of nutrients but only on cell density. There was a progressive increase in cell surface hydrophobicity with cell density in both axenic cultures and cultures grown with a bacterial substrate. It is proposed that it is these cell-density-related surface changes that account for the ability of amoebae grown in different conditions to sort out during subsequent development in a manner related to cell fate.