Quantitative morphologic studies during colonial growth of heteroploid cell strains differing in cell contact, shape and orientation

Abstract

Five-cloned strains differing in cell and colony morphology, which had been isolated from a HeLa-S3 culture, were plated at intervals during their propagation. Measurements of morphologic indices of cell-to-cell contact, cell surface of contact with substratum, cell shape and cell orientation were performed at serial intervals during colonial growth. Morphologic variation was associated with the strain and with the stage of development of the colony. Certain differences in cell shape and cell-to-cell contact among strains were expressed as early as the one- and two-celled colony stages respectively. Other differences among strains appeared at various times during colonial growth. Changes in the occurrence of contact among cells, in cell shape or in cell surface of contact with substratum took place during colonial growth of certain strains. These changes were reversible upon dispersion of the cells, were closely related to the growth of the cell population of the colony, and occurred in the absence of environmental changes introduced by the experimenter. The term growth related modulation is proposed for such changes. The pattern and timing of growth related modulation appeared to be heritable attributes of the strains. The possible mechanisms and significance of inter strain differences and of growth related modulation are discussed.