Uptake and metabolism of carbohydrates by Bradyrhizobium japonicum bacteroids
Bradyrhizobium japonicum bacteroids were isolated anaerobically and were supplied with /sup 14/C-labeled trehalose, sucrose, UDP-glucose, glucose, or fructose under low O/sub 2/ (2% in the gas phase). Uptake and conversion of /sup 14/C to CO/sub 2/ were measured at intervals up to 90 minutes. Of the five compounds studied, UDP-glucose was most rapidly absorbed but it was very slowly metabolized. Trehalose was the sugar most rapidly converted to CO/sub 2/, and fructose was respired at a rate of at least double that of glucose. Sucrose and glucose were converted to CO/sub 2/ at a very low but measurable rate (<0.1 nanomoles per milligram protein per hour). Carbon Number 1 of glucose appeared in CO/sub 2/ at a rate 30 times greater than the conversion of carbon Number 6 to CO/sub 2/, indicating high activity of the pentose phosphate pathway. Enzymes of the Entner-Doudoroff pathway were not detected in bacteroids, but very low activities of sucrose synthase and phosphofructokinase were demonstrated. Although metabolism of sugars by B. japonicum bacteroids was clearly demonstrated, the rate of sugar uptake was only 1/30 to 1/50 the rate of succinate uptake. The overall results support the view that, although bacteroids metabolize sugars, the rates are very low and are inadequate to support nitrogenase.
- Research Organization:
- Ohio State Univ., Wooster
- OSTI ID:
- 6549906
- Journal Information:
- Plant Physiol.; (United States), Vol. 83:3
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
FRUCTOSE
METABOLISM
GLUCOSE
LIGASES
ENZYME ACTIVITY
PHOSPHOTRANSFERASES
SACCHAROSE
ANAEROBIC CONDITIONS
BACTERIA
BIOLOGICAL PATHWAYS
CARBON 14 COMPOUNDS
CARBON DIOXIDE
TRACER TECHNIQUES
UPTAKE
ALDEHYDES
CARBOHYDRATES
CARBON COMPOUNDS
CARBON OXIDES
CHALCOGENIDES
DISACCHARIDES
ENZYMES
HEXOSES
ISOTOPE APPLICATIONS
KETONES
LABELLED COMPOUNDS
MICROORGANISMS
MONOSACCHARIDES
OLIGOSACCHARIDES
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PHOSPHORUS-GROUP TRANSFERASES
SACCHARIDES
TRANSFERASES
550501* - Metabolism- Tracer Techniques
550701 - Microbiology- Tracer Techniques