Gennemark Peter, Nordlander Bodil, Hohmann Stefan, Wedelin Dag
Department of Computer Science and Engineering, Chalmers University of Technology, SE-412 96 Göteborg, Sweden.
In Silico Biol. 2006;6(3):193-214.
We present a simple ordinary differential equation (ODE) model of the adaptive response to an osmotic shock in the yeast Saccharomyces cerevisiae. The model consists of two main components. First, a biophysical model describing how the cell volume and the turgor pressure are affected by varying extra-cellular osmolarity. The second component describes how the cell controls the biophysical system in order to keep turgor pressure, or equivalently volume, constant. This is done by adjusting the glycerol production and the glycerol outflow from the cell. The complete model consists of 4 ODEs, 3 algebraic equations and 10 parameters. The parameters are constrained from various literature sources and estimated from new and previously published absolute time series data on intra-cellular and total glycerol. The qualitative behaviour of the model has been successfully tested on data from other genetically modified strains as well as data for different input signals. Compared to a previous detailed model of osmoregulation, the main strength of our model is its lower complexity, contributing to a better understanding of osmoregulation by focusing on relationships which are obscured in the more detailed model. Besides, the low complexity makes it possible to obtain more reliable parameter estimates.
我们提出了一个简单的常微分方程（ODE）模型，用于描述酿酒酵母对渗透压冲击的适应性反应。该模型由两个主要部分组成。第一部分是一个生物物理模型，描述细胞体积和膨压如何受到细胞外渗透压变化的影响。第二部分描述细胞如何控制生物物理系统，以保持膨压或等效的体积恒定。这是通过调节甘油的产生和细胞内甘油的流出实现的。完整的模型由4个常微分方程、3个代数方程和10个参数组成。这些参数来自各种文献资料，并根据新的和先前发表的关于细胞内和总甘油的绝对时间序列数据进行估计。该模型的定性行为已在来自其他基因改造菌株的数据以及不同输入信号的数据上成功进行了测试。与之前详细的渗透调节模型相比，我们模型的主要优势在于其较低的复杂性，通过关注在更详细模型中被掩盖的关系，有助于更好地理解渗透调节。此外，低复杂性使得获得更可靠的参数估计成为可能。
