Auswanderung aus Deutschland Daten und Analysen zur internationalen
In den vergangenen Jahren hat sich eine intensive Debatte über die steigende Auswanderung aus Deutschland entwickelt. Besonders beunruhigend ist dabei die offensichtliche Tendenz der internationalen Migration der qualifiziertesten Arbeitskräfte. Jedoch le
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© Springer-Verlag 1997
O R I G I N A L PA P E R
Martina Selig · Karina B. Xavier · Helena Santos · Peter Schönheit
Comparative analysis of Embden-Meyerhof and Entner-Doudoroff glycolytic pathways in hyperthermophilic archaea and the bacterium Thermotoga Received: 8 July 1996 / Accepted: 4 November 1996
Abstract The Embden-Meyerhof (EM) or Entner-Doudoroff (ED) pathways of sugar degradation were analyzed in representative species of the hyperthermophilic archaeal genera Thermococcus, Desulfurococcus, Thermoproteus, and Sulfolobus, and in the hyperthermophilic (eu)bacterial genus Thermotoga. The analyses included (1) determination of 13C-labeling patterns by 1H- and 13C-NMR spectroscopy of fermentation products derived from pyruvate after fermentation of specifically 13C-labeled glucose by cell suspensions, (2) identification of intermediates of sugar degradation after conversion of 14C-labeled glucose by cell extracts, and (3) measurements of enzyme activities in cell extracts. Thermococcus celer and Thermococcus litoralis fermented 13C-glucose to acetate and alanine via a modified EM pathway (100%). This modification involves ADP-dependent hexokinase, 6-phosphofructokinase, and glyceraldehyde-3-phosphate:ferredoxin oxidoreductase (GAP:FdOR). Desulfurococcus amylolyticus fermented 13C-glucose to acetate via a modified EM pathway in which GAP:FdOR replaces GAP-DH/phosphoglycerate kinase. Thermoproteus tenax fermented 13C-glucose to low amounts of acetate and alanine via simultaneous operation of the EM pathway (85%) and the ED pathway (15%). Aerobic Sulfolobus acidocaldarius fermented 13Clabeled glucose to low amounts of acetate and alanine ex-
Dedicated to Professor A. Kröger on the occasion of his 60th birthday M. Selig · P. Schönheit Institut für Pflanzenphysiologie und Mikrobiologie, Fachbereich Biologie, Freie Universität Berlin, Königin-Luise-Strasse 12–16a, D-14195 Berlin, Germany K. B. Xavier · H. Santos Instituto de Tecnologia Química e Biológica, Apartado 127, 2780 Oeiras, Portugal P. Schönheit (Y) Institut für Allgemeine Mikrobiologie, Christian-Albrechts-Universität zu Kiel, Am Botanischen Garten 1–9, D-24118 Kiel, Germany Tel. +49-431-880-4330; Fax +49-431-880-2194
clusively via the ED pathway. The anaerobic (eu)bacterium Thermotoga maritima fermented 13C-glucose to acetate and lactate via the EM pathway (85%) and the ED pathway (15%). Cell extracts contained glucose-6-phosphate dehydrogenase and 2-keto-3-deoxy-6-phosphogluconate aldolase, key enzymes of the conventional phosphorylated ED pathway, and, as reported previously, all enzymes of the conventional EM pathway. In conclusion, glucose was degraded by hyperthermophilic archaea to pyruvate either via modified EM pathways with different types of hexose kinases and GAP-oxidizing enzymes, by the nonphosphorylated ED pathway, or by a combination of both pathways. In contrast, glucose catabolism in the hyperthermophilic (eu)bacterium Thermotoga involves the conventional forms of the EM and ED pathways. The data are in accordance with various previous
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