Forecasting trend output in the Euro area

This paper is an applied study about forecasting trend output and the output gap in the Euro area. The need for trend output forecasts is justified by an analysis of the monetary strategy of the European Central Bank. Trend output serves as a direct inflation indicator and helps to determine the reference value for money. For both purposes, trend output has to be forecasted. A permanent–transitory decomposition based on cointegration restrictions gives an estimate of trend output in the Euro area. Ex‐ante point forecasts of trend output are computed and bootstrap simulation is employed to construct prediction intervals that take estimation uncertainty into consideration. The uncertainty of trend output and the output gap is quite large and raises questions about their usefulness as indicators for monetary policy. Copyright © 2002 John Wiley & Sons, Ltd.     

Primary structure of Torpedo californica acetylcholinesterase deduced from its cDNA sequence

Acetylcholinesterase, an essential enzyme of the nervous system, rapidly terminates the action of acetylcholine released into the synapse. Acetylcholinesterase is also found (in lower abundance) in extrajunctional areas of muscle and nerve and on erythrocyte membranes. Hydrodynamic analyses of the native enzyme and characterization of its dissociated subunits have revealed multiple enzyme forms which can be divided into two classes: dimensionally asymmetric forms which are usually found within the synapse and contain a collagen-like structural subunit disulphide-linked to the catalytic subunits; and globular forms which appear to be widely distributed on the outer surface of cell membranes. Both forms have been characterized in the ray Torpedo californica and, although their catalytic behaviours seem to be identical, they differ slightly in amino-acid composition, peptide maps and reactivity with certain monoclonal antibodies. Here, we report the complete amino-acid sequence of an acetylcholinesterase inferred from the sequence of a complementary DNA clone. The 575-residue protein shows significant homology with the C-terminal portion of thyroglobulin.     

Paramyosin-Struktur und Sperrtonus,Untersuchungen am Byssusretraktor vonMytilus edulis mit dem Interferenz-Kontrast-Mikroskop

Summary Surviving muscle fibres of a molluscan smooth muscle (ABRM) in catch exhibit a characteristic pattern of longitudinal stripes when examined with theNomarski technique (Differential interference contrast). The pattern appears to be due to aggregated paramyosin-filaments; it disappears after abolishing the catch with 5-hydroxytryptamine or — in freeze-dried preparation — after raising the pH of the ATP-salt solution.     

Peptide selection by MHC class I molecules.

Synthetic peptides have been used to sensitize target cells and thereby screen for epitopes recognized by T cells. Most epitopes of cytotoxic T lymphocytes can be mimicked by synthetic peptides of 12-15 amino acids. Although in specific cases, truncations of peptides improves sensitization of target cells, no optimum length for binding to major histocompatibility complex (MHC) class I molecules has been defined. We have now analysed synthetic peptide captured by empty MHC class I molecules of the mutant cell line RMA-S. We found that class I molecules preferentially bound short peptides (nine amino acids) and selectively bound these peptides even when they were a minor component in a mixture of longer peptides. These results may help to explain the difference in size restriction of T-cell epitopes between experiments with synthetic peptides and those with naturally processed peptides.     

Bradykinin-induced stimulation of cardiac parasympathetic ganglia

Summary Bradykinin slows the heart rate of the rabbit isolated heart. It appears to act as a non-nicotine-like stimulant on the cardiac parasympathetic ganglia.We thank Miss L. Späth and Mr E. Schöffel for skilled technical assistance. This study was supported by the Deutsche Forschungsgemeinschaft.     

Structures of ParB bound to DNA reveal mechanism of partition complex formation

The faithful inheritance of genetic information, which is essential for all organisms, requires accurate DNA partition (segregation) at cell division. In prokaryotes, partition is mediated by par systems, for which the P1 plasmid system of Escherichia coli is a prototype comprising a partition site and two proteins, ParA and ParB. To form the partition complex necessary for segregation, P1 ParB must recognize a complicated arrangement of A-box and B-box DNA motifs located on opposite ends of a sharply bent parS partition site of approximately 74 bp (refs 3-7). Here we describe structures of ParB bound to partition sites. ParB forms an asymmetric dimer with extended amino-terminal HTH (helix-turn-helix) domains that contact A-boxes. The two HTH domains emanate from a dimerized DNA-binding module composed of a six-stranded beta-sheet coiled-coil that binds B-boxes. Strikingly, these individual DNA-binding modules rotate freely about a flexible linker, enabling them to contact several arrangements of A- and B-boxes. Most notably, each DNA-binding element binds to and thus bridges adjacent DNA duplexes. These unique structural features of ParB explain how this protein can bind complex arrays of A- and B-box elements on adjacent DNA arms of the looped partition site.     

Essential role for Nix in autophagic maturation of erythroid cells

Erythroid cells undergo enucleation and the removal of organelles during terminal differentiation. Although autophagy has been suggested to mediate the elimination of organelles for erythroid maturation, the molecular mechanisms underlying this process remain undefined. Here we report a role for a Bcl-2 family member, Nix (also called Bnip3L), in the regulation of erythroid maturation through mitochondrial autophagy. Nix(-/-) mice developed anaemia with reduced mature erythrocytes and compensatory expansion of erythroid precursors. Erythrocytes in the peripheral blood of Nix(-/-) mice exhibited mitochondrial retention and reduced lifespan in vivo. Although the clearance of ribosomes proceeded normally in the absence of Nix, the entry of mitochondria into autophagosomes for clearance was defective. Deficiency in Nix inhibited the loss of mitochondrial membrane potential (DeltaPsi(m)), and treatment with uncoupling chemicals or a BH3 mimetic induced the loss of DeltaPsi(m) and restored the sequestration of mitochondria into autophagosomes in Nix(-/-) erythroid cells. These results suggest that Nix-dependent loss of DeltaPsi(m) is important for targeting the mitochondria into autophagosomes for clearance during erythroid maturation, and interference with this function impairs erythroid maturation and results in anaemia. Our study may also provide insights into molecular mechanisms underlying mitochondrial quality control involving mitochondrial autophagy.     

A defined range of guard cell calcium oscillation parameters encodes stomatal movements.

Oscillations in cytosolic calcium concentration ([Ca2+]cyt) are central regulators of signal transduction cascades, although the roles of individual [Ca2+]cyt oscillation parameters in regulating downstream physiological responses remain largely unknown. In plants, guard cells integrate environmental and endogenous signals to regulate the aperture of stomatal pores and [Ca2+]cyt oscillations are a fundamental component of stomatal closure. Here we systematically vary [Ca2+]cyt oscillation parameters in Arabidopsis guard cells using a 'calcium clamp' and show that [Ca2+]cyt controls stomatal closure by two mechanisms. Short-term 'calcium-reactive' closure occurred rapidly when [Ca2+]cyt was elevated, whereas the degree of long-term steady-state closure was 'calcium programmed' by [Ca2+]cyt oscillations within a defined range of frequency, transient number, duration and amplitude. Furthermore, in guard cells of the gca2 mutant, [Ca2+]cyt oscillations induced by abscisic acid and extracellular calcium had increased frequencies and reduced transient duration, and steady-state stomatal closure was abolished. Experimentally imposing [Ca2+]cyt oscillations with parameters that elicited closure in the wild type restored long-term closure in gca2 stomata. These data show that a defined window of guard cell [Ca2+]cyt oscillation parameters programs changes in steady-state stomatal aperture.