The StrQ protein encoded in the gene cluster for 5''-hydroxystreptomycin of Streptomyces glaucescens GLA.0 is a alpha-D-glucose-1-phosphate cytidylyltransferase (CDP-D-glucose synthase)

Little is known about the coupling of serotonin 5-HT1B receptors to cellular signals other than cyclic AMP. In the present studies, the activation by 5-HT1B receptors of p70 S6 kinase and the mitogen-activated protein kinase (MAP kinase) ERK-2 was investigated. Studies were performed by using both nontransfected Chinese hamster ovary (CHO) cells, which express endogenous receptors at a very low density, and a stable transfected CHO cell line expressing 5-HT1B receptors at 230 fmol/mg of membrane protein, a density similar to that expressed in cortex. In nontransfected cells, 5-HT was found to stimulate a greater than twofold increase in MAP kinase activity with an EC50 of 20 nM. Reflecting increased density of receptors, 5-HT caused a greater than eightfold activation of ERK-2 in transfected cells with an EC50 of 2 nM. 5-HT was found to also stimulate p70 S6 kinase in both nontransfected and transfected cells. The stimulation was sixfold in both types of cells, but the EC50 for 5-HT was fourfold lower in transfected cells. The coupling of 5-HT1B receptors to ERK-2 and to p70 S6 kinase was inhibited by pertussis toxin, inhibitors of phosphatidylinositol 3-kinase, and by the inhibitor of MAP kinase kinase PD098059. Activation of p70 S6 kinase, but not ERK-2, was also inhibited by rapamycin. These findings demonstrate that 5-HT1B receptors couple to ERK-2 and p70 S6 kinase through overlapping, but nonidentical, pathways.     

Preventive maintenance scheduling by variable dimension evolutionary algorithms

Black box optimization strategies have been proven to be useful tools for solving complex maintenance optimization problems. There has been a considerable amount of research on the right choice of optimization strategies for finding optimal preventive maintenance schedules. Much less attention is turned to the representation of the schedule to the algorithm. Either the search space is represented as a binary string leading to highly complex combinatorial problem or maintenance operations are defined by regular intervals which may restrict the search space to suboptimal solutions. An adequate representation however is vitally important for result quality.     

Considerable plasma levels of a cytotoxic etoposide metabolite in patients undergoing high-dose chemotherapy

A 13-year-old boy with a paratesticular embryonal rhabdomyosarcoma and a large thrombus into the inferior vena cava reaching the suprahepatic vein is presented. We used cardiopulmonary bypass with deep hypothermic circulatory arrest to realize a complete exeresis of the tumor and thrombus, followed by systemic chemotherapy and radiotherapy. Ten years later the patient is alive and doing well without any sequelae.     

Zur Darstellung des magnetischen Feldes zweidimensionaler,homogen und inhomogen magnetisierter Körper

Ohne Zusammenfassung     

Vorkommen von Lipoxygenase, Katalase und Peroxidase in Weizenmehlen mit unterschiedlichen Backeigenschaften

Zusammenfassung In einem kanadischen Weizenmehl und in Mehlen aus zehn deutschen Weizensorten wurden die Aktivitäten der drei Enzyme gemessen. Die pH Profile der Lipoxygenase und der Katalase zeigten, daß beide Enzyme bei einem durchschnittlichen Teig-pH Wert von 6,2 aktiv sind. Zwischen den Backeigenschaften und den vorkommenden Enzymaktivitäten waren keine Beziehungen zu erkennen.

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Occurrence of lipoxygenase, catalase and peroxidase in wheat flours with different baking performances

Summary The activities of the three enzymes were determined in one Canadian and ten German wheat varieties. The pH-profiles of the lipoxygenase and the catalase indicated that both enzymes are active at the usual pH value (pH 6.2) of a dough. No correlations were detectable between the concentrations of the three enzymes and the baking performance of the flours.

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Gefördert von der AIF über den Forschungskreis der Ernährungsindustrie     

Microbial desulphurization of coal – development and application of a slurry reactor

Microbial desulphurization of coal by pyrite oxidizing enrichment cultures containing predominantly Thiobacillus ferrooxidans was performed in an air-agitated slurry reactor, 20 l in volume. A model of microbiological and chemical reactions, occurring at various points within the coal, was set up taking into account the pore structure of the coal. The influence of parameters relevant to industrial processes, such as superficial gas velocity, particle size, initial pyrite concentration, and slurry density of the coal, on the conversion of pyrite was examined. Variation of the superficial gas velocity in the range of 0.01 to 0.04 m/s confirmed that the reaction is not controlled by oxygen transfer from gaseous to liquid phase. The rate of pyrite oxidation depends mainly on the accessibility of pyrite to micro-organisms which is determined by the particle size of the coal as well as the distribution of pyrite crystals in the coal matrix. The accessibility of pyrite to the micro-organisms is described by the ratio of effective to maximum microbial activity, measured as oxygen consumption. Starting with higher initial concentration of pyrite in the coal increases the oxidation rate, according to first order kinetics. Enhanced slurry densities lead to a decrease of pyrite conversion, in spite of higher pyrite concentration. The maximum pyrite oxidation rate was measured at 15% (v/v) slurry density and 25°C as 1800 mg S_pyr/kg coal per day, or 360 mg S_pyr/l reactor volume per day.