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Abstract The phosphotransferase system (PTS) is the sugar transportation machinery that is widely distributed in prokaryotes and is critical for enhanced production of useful metabolites. To increase the glucose uptake rate, we propose a rational strategy for designing the molecular architecture of the Escherichia coli glucose PTS by using a computer‐aided design (CAD) system and verified the simulated results with biological experiments. CAD supports construction of a biochemical map, mathematical modeling, simulation, and system analysis. Assuming that the PTS aims at controlling the glucose uptake rate, the PTS was decomposed into hierarchical modules, functional and flux modules, and the effect of changes in gene expression on the glucose uptake rate was simulated to make a rational strategy of how the gene regulatory network is engineered. Such design and analysis predicted that the mlc knockout mutant with ptsI gene overexpression would greatly increase the specific glucose uptake rate. By using biological experiments, we validated the prediction and the presented strategy, thereby enhancing the specific glucose uptake rate.

Phenylalanine ammonialyase (PAL; EC 4.3.1.5) catalyses the first step in the phenylpropanoid pathway and is induced during differentiation and by various stimuli. In carrot (Daucus carota L. cv. Kurodagosun) suspension culture cells, PAL is slowly induced during anthocyanin synthesis which occurs in a medium lacking 2,4-dichlorophenoxyacetic acid and is also induced rapidly and transiently by transferring and diluting cells to fresh medium. Analyses of nucleotide sequences derived from PAL cDNAs revealed that the PAL mRNAs induced by transfer were transcribed from different carrot PAL genes than the PAL mRNAs induced during anthocyanin synthesis. Northern blotting using probes derived from 3' non-coding regions for PAL cDNAs confirmed that different PAL genes were induced during anthocyanin synthesis and after transfer. Induction of different PAL genes occurs in response to differences in the induction trigger. [ABSTRACT FROM AUTHOR]