Context-Dependent Flux Coupling via Conserved Small-Molecule Regulatory Structures

Small-molecule regulation modulates enzyme activity and is widespread in metabolic networks. However, the organization of small-molecule regulatory networks and its generalized role is not well understood. We analyze the structure of the genomewide Escherichia coli small-molecule regulatory network (SMRN) to reveal that it optimizes controllability in the metabolic network. This is achieved by conserved, highly overabundant incoherent feedforward loops. Using multi-omics data, we characterize loop examples in central carbon metabolism. These use signals from hypothesized flux-sensing >metabolites phosphoenolpyruvate, alpha-ketoglutarate, citrate, and malate to distinguish between glycolysis, gluconeogenesis, and glyoxylate shunt activity to differentially couple fluxes across these major modes of metabolism. Our results suggest that coupling of fluxes by direct modulation of enzyme activity is an emergent property of the SMRN that depends heavily on both regulatory structure and metabolic context via the metabolome, and further that flux sensing and coupling may be a global property of the metabolic network.

SIMULATION OF MOBILE ROBOT CLAMPING MAGNETS BY CIRCLE-FIELD METHOD

There are a list of complicated tasks need to be solved to increase the working productivity and decrease working cost in modern shipbuilding and ship repair. Good results in solving those problems are shown whether automation with varied robots implementation. The mobile robots able to move and perform given technological operations on different-spaced ferromagnetic surfaces are equipped with own control systems, movers and clamping devices. Usually, reliability and safety of such robots are in direct dependence on designers’ adequate representation of their behavior that is described by mathematical description of separate parts or the robot in the whole to correct control problem solving. The article amply considers the process of the climbing mobile robot clamping electromagnet simulation model building using the improved circle-field method on the example of BR-65/30 clamping electromagnet. The model is built on the basis of interpolated dependences of flux coupling and electromagnetic force on the magnetomotive force and the value of the air gap obtained by numerical calculations of the magnetic field. The dynamic properties of the electromagnet are investigated and a family of its traction characteristics is obtained by the developed model, which can be used for automatic control of the robot clamping device. References 25, figures 5, tables 3.