Levin M D, Morton-Firth C J, Abouhamad W N, Bourret R B, Bray D
Department of Zoology, University of Cambridge, United Kingdom.
Biophys J. 1998 Jan;74(1):175-81. doi: 10.1016/S0006-3495(98)77777-X.
Cells in a cloned population of coliform bacteria exhibit a wide range of swimming behaviors--a form of non-genetic individuality. We used computer models to examine the proposition that these variations are due to differences in the number of chemotaxis signaling molecules from one cell to the next. Simulations were run in which the concentrations of seven gene products in the chemotaxis pathway were changed either deterministically or stochastically, with the changes derived from independent normal distributions. Computer models with two adaptation mechanisms were compared with experimental results from observations on individuals drawn from genetically identical populations. The range of swimming behavior predicted for cells with a standard deviation of protein copy number per cell of 10% of the mean was found to match closely the experimental range of the wild-type population. We also make predictions for the swimming behaviors of mutant strains lacking the adaptational mechanism that can be tested experimentally.
一群克隆的大肠菌群细胞表现出广泛的游动行为——一种非遗传个体性的形式。我们使用计算机模型来检验这样一种观点，即这些变异是由于从一个细胞到另一个细胞的趋化信号分子数量的差异所致。进行了模拟，其中趋化途径中七种基因产物的浓度以确定性或随机性方式改变，这些改变源自独立的正态分布。将具有两种适应机制的计算机模型与从基因相同的群体中抽取的个体的观察实验结果进行了比较。发现预测的每个细胞蛋白质拷贝数标准差为平均值10%的细胞的游动行为范围与野生型群体的实验范围紧密匹配。我们还对缺乏可通过实验测试的适应机制的突变菌株的游动行为进行了预测。
