The heterogeneity of reaction fluxes present in metabolic networks can be exploited to construct disparity backbones as reduced version of metabolism. These backbones maintain all relevant information while displaying a substantially decreased number of interconnections and, hence, they become a useful tool to  unveil important biological information. Here, we apply the disparity filter method based on a high-flux fluctuation analysis to extract the metabolic backbones of two URLanisms, Escherichia coli and Mycoplasma pneumoniae, using computationally predicted fluxes that maximize their growth rate . We find that the metabolic backbones of URLanisms in minimal medium are mainly composed of a core of reactions belonging to ancient pathways, meaning that reactions in the early stages of the life of URLanisms still remain at present significant for biomass production. At the same time, a comparative analysis of  backbones in different media leads to the identification of pathways sensitive to environmental changes. Backbones, as networks of metabolic flux superhighways , are thus useful to trace simultaneously both long-term evolution and short-term adaptation fingerprints in cell metabolism.
The heterogeneity of reaction fluxes present in metabolic networks can be exploited to construct high-flux fluctuation backbones as reduced versions of metabolism. These backbones maintain all relevant information while displaying a substantially decreased number of interconnections and, hence, they become a useful tool to extract main metabolic highways and so to unveil important biological information. Here, we disclose the metabolic backbone of Escherichia coli using computationally predicted fluxes that maximize the growth rate in glucose medium, and we contrast it with the backbone of Mycoplasma pneumoniae, a much URLanism . We find that the core of both backbones are mainly composed of reactions in ancient pathways, meaning that those reactions still remain at present significant for biomass production. At the same time, a comparative analysis of E. coli backbones in different media leads to the identification of pathways sensitive to environmental changes. Backbones, as networks of metabolites connected by the most relevant fluxes , are thus useful to trace simultaneously both evolution and adaptation fingerprints in cell metabolism.
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disparity
high-flux fluctuation
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version
versions
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extract main metabolic highways and so to
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apply the disparity filter method based on a high-flux fluctuation analysis to extract the metabolic backbones of two URLanisms, Escherichia coli and Mycoplasma pneumoniae,
disclose the metabolic backbone of Escherichia coli
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their growth rate
the growth rate in glucose medium, and we contrast it with the backbone of Mycoplasma pneumoniae, a much URLanism
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metabolic backbones of URLanisms in minimal medium
core of both backbones
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a core of reactions belonging to
reactions in
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reactions in the early stages of the life of URLanisms
those reactions
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E. coli
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metabolic flux superhighways
metabolites connected by the most relevant fluxes
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long-term evolution and short-term
evolution and