Fisher P R, Smith E, Williams K L
Cell. 1981 Mar;23(3):799-807. doi: 10.1016/0092-8674(81)90444-x.
Developing cells of the cellular slime mold Dictyostelium discoideum release a low molecular weight metabolite (Slug Turning Factor, STF) which, at high uniform concentrations, interferes with phototaxis and thermotaxis by D. discoideum slugs. D. discoideum slugs migrating in darkness are repelled by (exhibit negative chemotaxis to) crude STF exudates. Dose-response curves relating the accuracies of phototaxis and negative chemotaxis to STF concentration indicate that, in both phototaxis and chemotaxis, slugs "measure" the ratios of STF concentrations on their opposite sides. Net STF release is enhanced by light. We propose that light, focused onto the slug's distal side by its convex surface, generates a lateral STF gradient in response to which the slug turns toward the light source.
细胞黏菌盘基网柄菌发育中的细胞会释放一种低分子量代谢物（蛞蝓转向因子，STF），在高浓度且均匀的情况下，它会干扰盘基网柄菌蛞蝓的趋光性和趋热性。在黑暗中迁移的盘基网柄菌蛞蝓会被粗制STF渗出物排斥（表现出对其的负趋化性）。将趋光性和负趋化性的准确性与STF浓度相关的剂量反应曲线表明，在趋光性和趋化性中，蛞蝓都“测量”其相对两侧STF浓度的比率。光照会增强STF的净释放。我们提出，通过蛞蝓凸面聚焦在其远端的光会产生横向STF梯度，蛞蝓会响应此梯度转向光源。
