Department of Physics, Informatics and Mathematics, University of Modena and Reggio Emilia, v. Campi 213a, 41125 Modena, Italy.
Department of Environmental Sciences (DAIS), University Ca' Foscari, Ca' Minich, S. Marco 2940, 30124 Venice, Italy.
Life (Basel). 2014 Dec 3;4(4):837-64. doi: 10.3390/life4040837.
In this paper a new model of growing and dividing protocells is described, whose main features are (i) a lipid container that grows according to the composition of the molecular milieu (ii) a set of "genetic memory molecules" (GMMs) that undergo catalytic reactions in the internal aqueous phase and (iii) a set of stochastic kinetic equations for the GMMs. The mass exchange between the external environment and the internal phase is described by simulating a semipermeable membrane and a flow driven by the differences in chemical potentials, thereby avoiding to resort to sometimes misleading simplifications, e.g., that of a flow reactor. Under simple assumptions, it is shown that synchronization takes place between the rate of replication of the GMMs and that of the container, provided that the set of reactions hosts a so-called RAF (Reflexive Autocatalytic, Food-generated) set whose influence on synchronization is hereafter discussed. It is also shown that a slight modification of the basic model that takes into account a rate-limiting term, makes possible the growth of novelties, allowing in such a way suitable evolution: so the model represents an effective basis for understanding the main abstract properties of populations of protocells.
本文描述了一种新的原生细胞生长和分裂模型，其主要特点是：（i）脂质容器根据分子环境的组成进行生长；（ii）一组在内部水相发生催化反应的“遗传记忆分子”（GMM）；（iii）一套用于 GMM 的随机动力学方程。通过模拟半透膜和由化学势差异驱动的流动来描述外部环境和内部相之间的质量交换，从而避免了有时会产生误导的简化，例如流动反应器的简化。在简单的假设下，只要反应集包含所谓的 RAF（自反自动催化，食物生成）集，就会在 GMM 和容器的复制率之间发生同步，此后将讨论 RAF 集对同步的影响。还表明，对基本模型进行微小的修改，考虑到限速项，就可以实现新颖性的生长，从而使合适的进化成为可能：因此，该模型代表了理解原生细胞群体的主要抽象特性的有效基础。
