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Solution Phosphorus-31 nuclear magnetic resonance (31P NMR) spectroscopy coupled with enzymatic hydrolysis (EH) with commercially available phosphatases was used to characterize phosphorus (P) compounds in extracts of the dominant aquatic macrophytes and algae in a eutrophic lake. Total extractable organic P (Po) concentrations ranged from 504 to 1643 mg kg-1 and 2318 to 8395 mg kg-1 for aquati...

Knowledge of the kinetics of the rod cyclic GMP phosphodiesterase is essential for understanding the kinetics and gain of the light response. Therefore, the interactions between Mg2+, cyclic GMP, and purified, trypsin-activated bovine rod cyclic GMP phosphodiesterase (EC 3.1.4.17) were examined. The effects of Mg2+ and of cyclic GMP on the rod phosphodiesterase activity were mutually concentrat...

Oxiranes are famous and very interesting compounds with a wide range application, they have found in the chemistry and industry. It is well known, that their ring opening is possible as in acidand in base reaction conditions, as well as by nucleophilic attack from the internal or external nucleophile molecule. The acid-catalyzed ring opening reaction has been described by T. Biela, P. Kubisa, R...

When isolated hepatocytes are incubated with phosphatidylinositol-specific phospholipase C, three cell-surface enzymes show markedly different behaviour. Most of the alkaline phosphatase is released at very low values of phosphatidylinositol hydrolysis, whereas further phosphatidylinositol hydrolysis releases only a maximum of about one-third of the 5'-nucleotidase. Alkaline phosphodiesterase I...

Specificity and versatility in cyclic AMP (cAMP) signalling are governed by the spatial localisation and temporal dynamics of the signal. Phosphodiesterases (PDEs) are important for shaping cAMP signals by hydrolyzing the nucleotide. In pancreatic β-cells, glucose triggers sub-plasma-membrane cAMP oscillations, which are important for insulin secretion, but the mechanisms underlying the oscilla...

Reaction of free 5-deazaflavin with Hz02 or m-chloroperoxybenzoate results in the formation of 4a,5epoxy derivatives. These compounds (Arna 340 nm) are nonfluorescent, decompose in neutral aqueous solution, and react with iodide to regenerate the original parent compound. The initial reaction of peroxides with 5-deazaFAD bound to oxynitrilase or with 5-deazaFMN bound to glycolate oxidase result...

Beta1- and beta2-adrenergic receptors (betaARs) are highly homologous, yet they play clearly distinct roles in cardiac physiology and pathology. Myocyte contraction, for instance, is readily stimulated by beta1AR but not beta2AR signaling, and chronic stimulation of the two receptors has opposing effects on myocyte apoptosis and cell survival. Differences in the assembly of macromolecular signa...

It has long been recognised that nest depredation by olfactory-searching mammals greatly influences the reproductive success of ground-nesting birds. Yet adaptations of birds to diminish smell during nesting have rarely been investigated. Recently, a remarkable shift in the composition of uropygial gland secretions (preen waxes) was discovered in many ground-nesting shorebirds and ducks that be...

A decentralized failure detection and isolation (FDI) methodology, which is robust with respect to model uncertainties and noise, is presented. Redundancy metrics are developed, and optimization problems are posed for the choices of robust parity relations. Closed-form solutions for some special failure cases are given. Connections are drawn with other disciplines, and the use of the metrics to...