Glycogen Synthase Kinase 3�� Interaction Protein Functions as an A-kinase Anchoring Protein

A-kinase anchoring proteins (AKAPs) include a family of scaffolding proteins that target protein kinase A (PKA) and other signaling proteins to cellular compartments and thereby confine the activities of the associated proteins to distinct regions within cells. AKAPs bind PKA directly. The interaction is mediated by the dimerization and docking domain of regulatory subunits of PKA and the PKA-binding domain of AKAPs. Analysis of the interactions between the dimerization and docking domain and various PKA-binding domains yielded a generalized motif allowing the identification of AKAPs. Our bioinformatics and peptide array screening approaches based on this signature motif identified GSKIP (glycogen synthase kinase 3β interaction protein) as an AKAP. GSKIP directly interacts with PKA and GSK3β (glycogen synthase kinase 3β). It is widely expressed and facilitates phosphorylation and thus inactivation of GSK3β by PKA. GSKIP contains the evolutionarily conserved domain of unknown function 727. We show here that this domain of GSKIP and its vertebrate orthologues binds both PKA and GSK3β and thereby provides a mechanism for the integration of PKA and GSK3β signaling pathways.     

Primary structure of the hemoglobins from the greater Kudu antelope (Tragelaphus strepsiceros)

The adult greater Kudu antelope has two hemoglobin components, Hb A and Hb B, with one alpha and two beta chains. The complete amino-acid sequences of these three chains are presented. The two beta chains differ only in one residue at position 16 (Gly----Ser) and may be the product of two allelic genes. The primary structure of the chains was determined by sequencing the tryptic peptides after their isolation from the tryptic digest of the chains by high performance liquid chromatography. The alignment of these peptides was deduced from homology with the chains of bovine hemoglobin. Between the Kudu hemoglobins and those of cattle a high degree of homology was found.     

Structures, spectroscopy and modeling of a rare set of isomeric copper(II) complexes

The structures and spectroscopic properties of various conformations of two diasteromeric pairs of enantiomers of pentacoordinate Cu^II bispidine complexes with chiral tetradentate ligands are reported. With one of the ligands an interesting type of distortional isomerism was observed experimentally, and this was studied in detail on the basis of the experimental structural and spectroscopic data (UV-Vis-NIR, EPR) and a DFT-, MM- and ligand-field-theory-based analysis.     

Oxygenation of mitochondrial membranes by the reticulocyte lipoxygenase. Action on monoamine oxidase activities A and B

Incubation of isolated rat liver mitochondria with the pure rabbit reticulocyte lipoxygenase caused a time-dependent inactivation of the monoamine oxidase activities A and B. Furthermore, a conversion of the monoamine oxidase into a diamine oxidase was observed. The inactivation kinetics for both monoamine oxidase activities A and B showed a biphasic behaviour; a reversible short-term inhibition during the first 5 min of incubation was followed by an irreversible inactivation of the enzyme. The kinetic studies suggest that the slow irreversible inactivation of the monoamine oxidase activities is due to secondary reactions subsequent to the initial attack of the lipoxygenase on the mitochondrial outer membrane. During the interaction of the lipoxygenase with the mitochondria, only about 1.5% of the polyenoic fatty acids present in the mitochondrial membranes were oxygenated. The predominant products formed during the interaction of the lipoxygenase with the mitochondrial membranes are (13S)-hydro(pero)xy-9Z,11E-octadecadienoic acid and (15S)-hydro(pero)xy-5,8,11,13(Z,Z,Z,E)-eicosatetraenoic acid.     

Lysimachia Zavadskii Wiesner

Ohne Zusammenfassung     

Rheological properties of cross-linked hyaluronan-gelatin hydrogels for tissue engineering

Hydrogels that mimic the natural extracellular matrix (ECM) are used in three-dimensional cell culture, cell therapy, and tissue engineering. A semi-synthetic ECM based on cross-linked hyaluronana offers experimental control of both composition and gel stiffness. The mechanical properties of the ECM in part determine the ultimate cell phenotype. We now describe a rheological study of synthetic ECM hydrogels with storage shear moduli that span three orders of magnitude, from 11 to 3 500 Pa, a range important for engineering of soft tissues. The concentration of the chemically modified HA and the cross-linking density were the main determinants of gel stiffness. Increase in the ratio of thiol-modified gelatin reduced gel stiffness by diluting the effective concentration of the HA component.     

Zur Erklärung der wechselnden Geschwindigkeit des Vegetationsrhythmus

Ohne Zusammenfassung     

A fluorescence assay demonstrating stimulation of phagocytosis by haemolymph molecules of Gallerta mellonella

An in vitro microscopic fluorescence assay determining the phagocytic activity of isolated plasmatocytes of Galleria mellonella is described. It was developed to quantify insect cellular immune reactions. The assay, a modification of a method originally established for vertebrate blood cells, is based on the quenching effect of trypan blue on fluorescein-isothiocyanate-labelled yeast cells. Only ingested yeast cells retain their fluorescence after quenching and can be easily distinguished from adhering ones. The technique is highly reproducible and easy to perform. Using this method a phagocytosis-stimulating effect caused by a haemolymph fraction > 100 kDa isolated from G. mellonella is demonstrated.