Coordinated control

Figure 18-8. Coordinated control of glycogenolysis and glycogenesis by cAMP-dependent protein kinase. The reactions that lead to glycogenolysis as a result of an increase in cAMP concentrations are shown with bold arrows, and those that are inhibited by activation of protein phosphatase-1 are shown as broken arrows. The reverse occurs when cAMP concentrations decrease as a result of phosphodiesterase activity, leading to glycogenesis.

Purine and pyrimidine biosynthesis parallel one another mole for mole, suggesting coordinated control of their biosynthesis. Several sites of cross-regulation characterize purine and pyrimidine nucleotide biosynthesis. The PRPP synthase reaction (reaction 1, Figure 34-2), which forms a precursor essential for both processes, is feedback-inhibited by both purine and pyrimidine nucleotides. 

Lopez JM, Bennett MK, Sanchez HB, Rosenfeld JM, Osborne TE. Sterol regulation of acetyl coenzyme A carboxylase a mechanism for coordinate control of cellular lipid. Proc Natl Acad Sci USA 1996 93 1049-1053. 

B. Grocholsky, A. Makarenko, and H. Durrant-Whyte, Information-theoretic coordinated control of multiple sensor platforms, in Proceedings of the IEEE International Conference on Robotics and Automation, Taipei, Taiwan, September 2003, pp. 1521-1526. 

Schematic representation of the various reaction modes for the dissolution of Fe(III)(hydr)oxides a) by protons b) by bidentate complex formers that form surface chelates. The resulting solute Fe(III) complexes may subsequently become reduced, e.g., by HS c) by reductants (ligands with oxygen donor atoms) such as ascorbate that can form surface complexes and transfer electrons inner-spheri-cally d) catalytic dissolution of Fe(III)(hydr)oxides by Fe(II) in the presence of a complex former e) light-induced dissolution of Fe(III)(hydr)oxides in the presence of an electron donor such as oxalate. In all of the above examples, surface coordination controls the dissolution process. (Adapted from Sulzberger et al., 1989, and from Hering and Stumm, 1990.)...

In the plantaricin system, five operons are coordinately controlled by the plantaricin A signaling system. In addition to the regulatory operon, two operons encode bacteriocin precursors and immunity proteins, one operon encodes the transport system of the bacteriocins and the PP itself, and the last operon contains four genes of unknown function (it could be a bacteriocin encoding operon but no activity has been found so far). The key operon encoding the three-component signaling pathway (composed of a PP, an HPK, and two RRs) will be discussed below. 

Coordinate Control of the Lactose Operon by Glucose and Lactose... 

Rates of sorption and desorption of phosphate. Eur. J. Soil Sd. 48 101-114 Strens, R.G.S. Wood, B.J. (1979) Diffuse reflectance spectra and optical properties of some iron and titanium oxides and oxyhydr-oxides. Min. Mag. 43 347—354 Stumm, W. Eurrer, G. (1987) The dissolution of oxides and aluminum silicates Examples of surface-coordination-controlled kinetics. 

The isolation of mutants in S. typhimurium by Rick and Osborn (11,12) and mutants in E. coli by Nishijima and Raetz (44) that accumulate the Lipid A precursor indicate that KDO synthesis and Lipid A synthesis are not coordinately controlled. The initial steps in the synthesis of the Lipid A precursor are totally unknown. The temperature sensitive mutants of E. coli isolated by Nishijima and Raetz (44) that are defective in phosphaditylglyc-erol phosphate synthesis at 42°C and accumulate the Lipid A precursors indicate that there is some relationship between the synthesis of phosphatidylglycerol and LPS. The reasons for the acu-cumulation of the Lipid A precursors in this E. coli mutant are not obvious. We have shown that CDP-diglyceride, one of the substrates for phosphatidylglycerol phosphate synthesis, is an inhibitor of D-arabinose-5-phosphate isomerase with an 1 value... 

The biochemical parameters of myelination appear to be controlled in a coordinated manner. That is, the parameters we measured responded in the same direction and degree to a certain condition of growth. For example, the cyclic nucleotide phospho-hydrolase and incorporation of into lipids both were less active in cultures from the newborn mouse than from the 15 day fetus. In addition the developmental pattern of all of the activities measured occurred in parallel and were all highest at about the same growth period. This coordinated control suggests that they are derived from a central source, such as a single cell type (for example, oligodendroglia) of brain. 

Midterm (1-10 years) scope specific to the structural aspects of the organization including divisions, reporting relationships, coordination, control viewpoint is internal—how the company organizes itself. 

Stumm, W. and Furrer, G. (1987) The solution of oxides and aluminium silicates examples of surface-coordination-controlled kinetics. In Aquatic Surface Chemistry Chemical Process at the Particle-Water Interface (ed. Stumm, W.). John Wiley and Sons, New York. 

The major source of free fatty acids in the blood is from the breakdown of triacylglycerol stores in adipose tissue which is regulated by the action of hormone-sensitive triacylglycerol lipase (see Topic K4). Fatty acid breakdown and fatty acid synthesis are coordinately controlled so as to prevent a futile cycle (see Topic K3). 

The anabolic hormone insulin has the opposite effect to glucagon and epinephrine. It stimulates the formation of triacylglycerols through decreasing the level of cAMP, which promotes the dephosphorylation and inactivation of hormone-sensitive lipase (Fig. 5). Insulin also stimulates the dephosphorylation of acetyl CoA carboxylase, thereby activating fatty acid synthesis (see Topic K3). Thus fatty acid synthesis and degradation are coordinately controlled so as to prevent a futile cycle. 

Recently, a novel approach for probing proximity effects in this type of dyad by using an axial ligand coordination-controlled tail-on and tail-off binding mechanism was reported [209]. The donor-acceptor proximity has been controlled either by temperature or by an axial ligand replacement and is illustrated in Scheme 10. 

The final organisational structure to be considered is the matrix. Matrix organisations grew out of the need to have a compromise between the functional grouping responsible for competence and resource utilisation, and the product grouping responsible for coordination, control and goal accountability. There are three basic types of matrix organisation. 

We also introduced the idea of composite control, which is based on the use of separate, coordinated controllers for the fast and slow components of the dynamics. 

What would be needed for the coordinate control of expression (at the transcriptional level) of a number of genes not located next to one another on the chromosome ... 

Different computer designs are used. As an example there are computer coordinator controllers. These groups of controllers are connected together so that they may all be changed at the same time from a single point. Also used are multi-zone microprocessors that monitor temperature, pressure, output rate, etc. that send either independently or coordinated signals from several sensors to achieve a more reliable and efficient performance. The microprocessor has to carry out control and monitoring functions such as ... 

Figure 6.170(b) Central module (CPU), to be clipped on a 35mm standard rail. With a microprocessor, RAM and EPROM/OTP, it coordinates, controls and monitors all the functions of a station. 

Construction Management involves the coordination, control, and management of the contractors performing the various construction activities as well as providing them with a clean and safe environment. The person, or entity, performing this function is called the Construction Manager (C.M.). 

We know that chloroplasts and mitochondria are never synthesized de novo their membranes grow by insertion of new elements into pre-existing membranes. How is the insertion of these new elements controlled Are pre-existing elements inserted into the membrane or are newly synthesized elements assembled into the membrane Is the insertion of these new elements controlled post-translationally or on the level of gene expression Are all of the different complexes coordinately controlled and assembled at the same rate Is assembly of a single protein complex the result of an ordered or a concerted mechanism ... 

Fig. 10.13 Coordinated Control of Fat Synthesis and Breakdown via Acetyl CoA and Malonyl...

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