Exobiology Branch, National Aeronautics and Space Administration Ames Research Center, Moffett Field, CA 94035.
Proc Natl Acad Sci U S A. 2014 Jan 7;111(1):208-13. doi: 10.1073/pnas.1315521110. Epub 2013 Dec 12.
A major theme driving research in biology is the relationship between form and function. In particular, a longstanding goal has been to understand how the evolution of multicellularity conferred fitness advantages. Here we show that biofilms of the bacterium Pseudomonas aeruginosa produce structures that maximize cellular reproduction. Specifically, we develop a mathematical model of resource availability and metabolic response within colony features. This analysis accurately predicts the measured distribution of two types of electron acceptors: oxygen, which is available from the atmosphere, and phenazines, redox-active antibiotics produced by the bacterium. Using this model, we demonstrate that the geometry of colony structures is optimal with respect to growth efficiency. Because our model is based on resource dynamics, we also can anticipate shifts in feature geometry based on changes to the availability of electron acceptors, including variations in the external availability of oxygen and genetic manipulation that renders the cells incapable of phenazine production.
一个推动生物学研究的主要主题是形式和功能之间的关系。特别是，一个长期的目标一直是了解多细胞生物的进化如何赋予了适应性优势。在这里，我们表明，铜绿假单胞菌的生物膜产生了最大限度地促进细胞繁殖的结构。具体来说，我们开发了一个关于菌落特征内资源可用性和代谢反应的数学模型。该分析准确地预测了两种类型的电子受体的测量分布：大气中可用的氧气，以及由细菌产生的氧化还原活性抗生素吩嗪。利用该模型，我们证明了菌落结构的几何形状在生长效率方面是最优的。由于我们的模型基于资源动态，我们还可以根据电子受体可用性的变化来预测特征几何形状的变化，包括外部氧气可用性的变化和使细胞无法产生吩嗪的遗传操作。
