Fine regulation

Muscle contraction is a delicate dynamic balance of the attachment and detachment of myosin heads to F-actin, subject to fine regulation via the nervous system. 

The / 2-subunit isoform seems to have a function as a recognition element for cell adhesion in the brain. This association may also mediate fine regulation of transport because antibodies to the pi subunit (AMOG = association molecule of glia) cause dissociation of cell-cell adhesion and stimulate Na,K-transport [51]. 

Keywords. Poly(3-hydroxybutyrate), Metabolic sequences, Fine regulation, Poly(3HB) cycle, Strategic survival polymer, Growth-associated synthesis, Energy-generating and -consuming synthesis, Optimization... 

At least two enzymes compete for acetyl-CoA - the citrate synthase and 3-ke-tothiolase. The affinities of these enzymes differ for acetyl-CoA (Table l),and at low concentrations of it the citrate synthase reaction tends to dominate, provided that the concentration of 2/H/ is not inhibiting. The fine regulation of the citrate synthases of various poly(3HB) accumulating bacteria has been studied [ 14, 47, 48]. They appear to be controlled by cellular energy status indicators (ATP, NADH, NADPH) and/or intermediates of the TCA cycle. The 3-ketothio-lase has also been investigated [10-14,49, 50]. This enzyme is, above all, inhibited by CoASH [10,14,49]. This important feature will be further considered below. 

Surprisingly, the fine regulation of the enzymes involved in poly(3HB) degradation has been hardly investigated at all (cf. Chap. 10 of this book). Most of the research on intracellular mobilization of poly(3HB) and oxidation of the monomers was done more than 25 years ago. 

Water. Water resorption in the proximal tubule is a passive process in which water follows the osmotically active particles, particularly the Na" ions. Fine regulation of water excretion (diuresis) takes place in the collecting ducts, where the peptide hormone vasopressin (antidiuretic hormone, ADH) operates. This promotes recovery of water by stimulating the transfer of aquaporins (see p. 220) into the plasma membrane of the tubule cells via V2 receptors. A lack of ADH leads to the disease picture of diabetes insipidus, in which up to 30 L of final urine is produced per day. 

To arrange NC or nanoparticles into an assembly is inevitable in order to utilize them for practical purposes. An assemblage in a finely regulated manner is always desired. It is therefore developed to control the interparticle separation. One of the most interesting methods, very rational but not too complicated, is the use of the thermal change in the state of surfactants adsorbed on the surface of nanoparticles. Kotov et al. (30) showed that the interparticle separation of titania NC of 2.0 0.5 nm could be controlled from 0.9 nm to 0.2 nm depending on the heat treatment condition, from 90 min at 70°C to 120 min at 90°C. 

Report on the importance of multiple phosphorylation sites in the fine regulation of protein function. 

A discussion of the role of LHC phosphorylation and/or cation effects as mechanisms of regulation of energy distribution between the two photosystems in vivo is beyond the scope of this review. However, it seems likely that both mechanisms might cooperate in vivo to achieve a fine regulation of energy distribution to the two light reactions of photosynthesis and therefore an adaptation to the prevailing illumination conditions. 

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