Sozinova Olga, Jiang Yi, Kaiser Dale, Alber Mark
Department of Mathematics and Center for the Study of Biocomplexity, University of Notre Dame, Notre Dame, IN 46556-5670, USA.
Proc Natl Acad Sci U S A. 2005 Aug 9;102(32):11308-12. doi: 10.1073/pnas.0504259102. Epub 2005 Aug 1.
Myxobacteria provide one of the simplest models of cell-cell interaction and organized cell movement leading to cellular differentiation. When starved, tens of thousands of cells change their movement pattern from outward spreading to inward concentration; they form aggregates that become fruiting bodies. Cells inside fruiting bodies differentiate into round, nonmotile, environmentally resistant spores. Traditionally, cell aggregation has been considered to imply chemotaxis; a long-range cell interaction. However, myxobacterial aggregation is the consequence of direct cell-contact interactions, not chemotaxis. We present here a 3D stochastic lattice-gas cellular automata model of cell aggregation based on local cell-cell contact, and no chemotaxis. We demonstrate that a 3D discrete stochastic model can simulate two stages of cell aggregation. First, a "traffic jam" forms embedded in a field of motile cells. The jam then becomes an aggregation center that accumulates more cells. We show that, at high cell density, cells stream around the traffic jam, generating a 3D hemispherical mound. Later, when the nuclear traffic jam dissolves, the aggregation center becomes a 3D ring of streaming cells.
粘细菌提供了细胞间相互作用和有组织的细胞运动导致细胞分化的最简单模型之一。饥饿时，数以万计的细胞将其运动模式从向外扩散转变为向内聚集；它们形成聚集体，进而变成子实体。子实体内的细胞分化为圆形、不运动、具有环境抗性的孢子。传统上，细胞聚集被认为意味着趋化作用，即一种远距离的细胞间相互作用。然而，粘细菌的聚集是直接细胞接触相互作用的结果，而非趋化作用。我们在此提出一种基于局部细胞间接触且无趋化作用的细胞聚集三维随机格子气元胞自动机模型。我们证明，一个三维离散随机模型可以模拟细胞聚集的两个阶段。首先，在运动细胞的场中形成一个“交通堵塞”。然后，这个堵塞变成一个聚集中心，积累更多细胞。我们表明，在高细胞密度下，细胞围绕交通堵塞流动，形成一个三维半球形丘。后来，当核心交通堵塞消散时，聚集中心变成一个由流动细胞组成的三维环。
