Systemic approaches to the study of a biological cell or tissue rely increasingly on the use of context-specific metabolic network models. The reconstruction of such a model from high-throughput data can routinely involve large numbers of tests under different conditions and extensive parameter tuning, which calls for fast algorithms. We present FASTCORE, a generic algorithm for reconstructing context-specific metabolic network models from global genome-wide metabolic network models such as Recon X. FASTCORE takes as input a core set of reactions that are known to be active in the context of interest (e.g., cell or tissue), and it searches for a flux consistent subnetwork of the global network that contains all reactions from the core set and a minimal set of additional reactions. Our key observation is that a minimal consistent reconstruction can be defined via a set of sparse modes of the global network, and FASTCORE iteratively computes such a set via a series of linear programs. Experiments on liver data demonstrate speedups of several orders of magnitude, and significantly more compact reconstructions, over a chief rival method. Given its simplicity and its excellent performance, FASTCORE can form the backbone of many future metabolic network reconstruction algorithms.
Phylogenetic tree reconstruction from genome-scale metabolic models
Universidad Católica de Valencia San Vicente Mártir(瓦伦西亚天主教大学圣维森特马蒂尔);Instituto Universitario de Matemática Pura y Aplicada, Universidad Politécnica de Valencia(瓦伦西亚理工大学纯数学与应用数学研究所)
Fast reconstruction of compact context-specific metabolic networks via integration of microarray data
最近,我们提出了一种用于快速重建紧凑上下文特定代谢网络(FASTCORE)的算法,该算法允许将重建时间降低到秒的时间量级(Vlavis et al.,2014年)。这种极低的计算需求为提高模型的质量开辟了新的可能性。重建高质量的模型需要几轮模型重建、根据真实实验数据测试模型的预测、输入模型和核心反应集的管理步骤以及交叉验证分析。这些半自动化的模型策展步骤在这种程度上是不可能的竞争算法,由于他们的高计算需求。为了适应FASTCORE的集成微阵列数据,因此,我们提出了一个新的工作流程:FASTCORMICS。FASTCORMICS需要输入微阵列数据和基因组规模的重建。FASTCORMICS没有启发式参数设置,并且具有低计算需求,总体构建时间大约为几分钟。FASTCORMICS用离散化工具Barcode预处理微阵列数据(Zillox等,2007)。条形码使用关于给定微阵列平台的每个探针组的强度分布的先验知识,以在表达的基因和非表达的基因之间分离。该预处理步骤允许规避设置启发式表达阈值的需要,这对于输出模型是关键的,因为响应于该阈值,可能包括或排除替代路径或子系统,从而严重改变模型的功能。一般来说,FASTCORMICS优于竞争算法,并允许以高吞吐量的方式获得高质量,鲁棒的模型。这将允许使用代谢建模作为用于分析微阵列数据的常规过程,例如在个性化医学领域。
Automation on the generation of genome scale metabolic models
Universidad Pinar del Río “Hermanos Saíz Montes de Oca”(比纳尔德里奥大学“塞斯·蒙特斯·德奥卡兄弟”);Cátedra Energesis de Tecnología Interdisciplinar, Universidad Católica de Valencia San Vicente Mártir(瓦伦西亚天主教圣文森特马蒂尔跨技术学院Energesis);Instituto Universitario de Matemática Pura y Aplicada, Universidad Politécnica de Valencia(瓦伦西亚理工大学纯数学与应用数学大学研究所)