Michigan State University-Department of Energy, Plant Research Laboratory, Michigan State University, East Lansing, Michigan 48824.
Proc Natl Acad Sci U S A. 1983 Sep;80(18):5646-9. doi: 10.1073/pnas.80.18.5646.
Thermotaxis by individual amoebae of Dictyostelium discoideum on a temperature gradient is described. These amoebae show positive thermotaxis at temperatures between 14 degrees C and 28 degrees C shortly (3 hr) after food depletion. Increasing time on the gradient reduces the positive thermotactic response at the lower temperature gradients (midpoint temperatures of 14, 16, and 18 degrees C), and amoebae show an apparent negative thermotactic response after 12 hr on the gradient. The thermotaxis response curve for "wild-type" amoebae after 16 hr on the gradient is similar to that shown for the pseudoplasmodia. Growth of the amoebae at a different temperature causes a shift in the thermotaxis response curve for the amoebae. This adaptation is similar to that shown for the pseudoplasmodia. Two mutants in thermotaxis, HO428 and HO813, show changes in amoebal thermotaxis similar to the observed changes in pseudoplasmodial thermotaxis. On the basis of the similarities between these responses, thermotaxis by the amoebae is proposed to be the basis for thermotaxis by the multicellular pseudoplasmodium.
描述了在温度梯度上单个变形虫的温度趋性。在食物耗尽后不久（3 小时），这些变形虫在 14 到 28 摄氏度之间表现出正趋温性。在较低的温度梯度（中点温度为 14、16 和 18 摄氏度）上，在梯度上的时间增加会降低正趋温反应，并且在梯度上 12 小时后，变形虫表现出明显的负趋温反应。在梯度上 16 小时后，“野生型”变形虫的趋热反应曲线与假变形虫相似。在不同温度下生长会导致变形虫的趋热反应曲线发生转移。这种适应类似于假变形虫的适应。两种在温度趋性上发生突变的突变体 HO428 和 HO813，其变形虫的温度趋性变化与假变形虫的温度趋性变化相似。基于这些反应的相似性，提出了变形虫的温度趋性是多细胞假变形体温度趋性的基础。
