Sugar metabolism in the extremely halophilic bacterium Salinibacter ruber.
Growth of Salinibacter ruber, a red, extremely halophilic bacterium phylogenetically affiliated with the Flavobacterium/Cytophaga branch of the domain Bacteria, is stimulated by a small number of sugars (glucose, maltose, starch at 1 g l(-1)). Glucose consumption starts after other substrates have been depleted. Glucose metabolism proceeds via a constitutive, salt-inhibited hexokinase and a constitutive salt-dependent nicotinamide adenine dinucleotide phosphate (NADP)-linked glucose-6-phosphate dehydrogenase. Glucose dehydrogenase and fructose-1,6-bisphosphate aldolase activity could not be detected. It is therefore suggested that Salinibacter metabolizes glucose by the classic Entner-Doudoroff pathway and not by the Embden-Meyerhof glycolytic pathway or by the modified Entner-Doudoroff pathway present in halophilic Archaea of the family Halobacteriaceae, in which the phosphorylation step is postponed. However, activity of 2-keto-3-deoxy-6-phosphogluconate aldolase could not be detected in extracts of Salinibacter cells, whether or not grown in the presence of glucose.
Oren
Aharon
A
Division of Microbial and Molecular Ecology, The Institute of Life Sciences, and the Moshe Shilo Minerva Center for Marine Biogeochemistry, The Hebrew University of Jerusalem, 91904 Jerusalem, Israel. orena@shum.cc.huji.ac.il
Mana
Lili
L
D000446:Aldehyde-Lyases / Q000378:metabolism; D001419:Bacteria / Q000201:enzymology* / Q000254:growth & development; D003470:Culture Media; D005634:Fructose-Bisphosphate Aldolase / Q000378:metabolism; D005947:Glucose / Q000378:metabolism*; D005954:Glucosephosphate Dehydrogenase / Q000378:metabolism; D019622:Haloferax volcanii / Q000201:enzymology*; D006593:Hexokinase / Q000378:metabolism
D003470:Culture Media; D005954:Glucosephosphate Dehydrogenase; D006593:Hexokinase; D000446:Aldehyde-Lyases; D005634:Fructose-Bisphosphate Aldolase; C100131:phospho-2-keto-3-deoxy-gluconate aldolase; D005947:Glucose