Panfilov AV, Hogeweg P
Department of Theoretical Biology, University of Utrecht, Padualaan 8, Utrecht, 3584 CH, The Netherlands.
J Theor Biol. 1999 Aug 7;199(3):297-309. doi: 10.1006/jtbi.1999.0958.
Dictyostelium discoideum slugs show a pronounced thermotaxis. We have modelled the motion of the D. discoideum slug in the absence and in the presence of a thermal gradient. Our model is an extension of the hybrid cellular automata/partial differential equation model, as formulated by Savill and Hogeweg [J. theor. Biol., (1997) 184, 229-235]. The modelled slugs maintain their shape and crawl, with a velocity depending on slug size, as found in experiments. Moreover, they show thermotactic behaviour: independent of the initial orientation, after some transient process, the slugs start moving along the temperature gradient. The slug behaviour in our model is due to the collective behaviour of the amoebae. Individual amoebae can neither respond to a shallow temperature gradient, nor show differentiation in motion velocity. The behaviour is achieved by a modification of the cyclic AMP waves: differences in temperature alter the excitability of the cell, and thereby the shape of the cyclic AMP wave. Chemotaxis towards cyclic AMP causes the slug to turn. We show that the mechanism still functions at very low signal-to-noise ratios. Copyright 1999 Academic Press.
盘基网柄菌蛞蝓表现出明显的趋温性。我们对有无热梯度情况下盘基网柄菌蛞蝓的运动进行了建模。我们的模型是对Savill和Hogeweg [《理论生物学杂志》，(1997) 184, 229 - 235]所提出的混合细胞自动机/偏微分方程模型的扩展。如实验中所发现的那样，建模的蛞蝓保持其形状并爬行，其速度取决于蛞蝓的大小。此外，它们表现出趋温行为：与初始方向无关，经过一些瞬态过程后，蛞蝓开始沿着温度梯度移动。我们模型中的蛞蝓行为是由于变形虫的集体行为所致。单个变形虫既不能对浅温度梯度做出反应，也不能在运动速度上表现出差异。这种行为是通过对环磷酸腺苷（cAMP）波的修改来实现的：温度差异改变了细胞的兴奋性，从而改变了环磷酸腺苷波的形状。对环磷酸腺苷的趋化作用导致蛞蝓转向。我们表明该机制在非常低的信噪比下仍能起作用。版权所有1999年学术出版社。
