1887

Abstract

A method employing temperature shifts was used to obtain extremely synchronous growth of amoebae of Ax-2 in axenic medium. When exponentially growing cells at 22·0 °C were shifted to 11·5 °C and shaken for 20 h, they exhibited good synchrony upon further culture at 22·0 °C. A relatively narrow range of low temperature (about 11·5 °C) and of treatment time (20 · 0°5 h) was necessary for inducing the best synchrony. This temperature-shift method is simple and practical and should be useful for detailed cellular and molecular investigations of growth regulation and of the relationship between the cell cycle and the differentiation of developing cells.