Rapid synthesis and metabolism of glutamate in N/sub 2/-fixing bacteroids. [Bradyrhizobium japonicum]
Symbiotic nodule bacteroids are thought to support N/sub 2/ fixation mainly by metabolizing dicarboxylic acids to CO/sub 2/, generating reductant and ATP required by nitrogenase. Bradyrhizobium japonicum bacteroids were isolated anaerobically and incubated at 2% O/sub 2/ with /sup 14/C-labeled succinate, malate, glutamate, or aspartate. /sup 14/CO/sub 2/ was collected, and the bacteroid contents separated into neutral, organic acid, and amino acid fractions. The respiration of substrates, relative to their uptake, was malate > glutamate > succinate > aspartate. Analysis of the fractions revealed that will all substrates the radioactivity was found mostly in the amino acid fraction. The labeling of the neutral fraction was negligible and only a small amount of label was found in the organic acid fraction indicating a small pool size. TLC of the amino acid fraction showed the label to be principally in glutamate. Glutamate contained 67, 80, 97, and 88% of the /sup 14/C in the amino acid fraction in bacteroids fed with succinate, malate, glutamate and aspartate, respectively. The data suggest that glutamate may play an important role in the bacteroid function.
- Research Organization:
- Ohio State Univ., Wooster
- OSTI ID:
- 6065683
- Report Number(s):
- CONF-8707108-; TRN: 87-037466
- Journal Information:
- Plant Physiol., Suppl.; (United States), Vol. 83:4; Conference: Annual meeting of the American Society of Plant Physiologists, St. Louis, MO, USA, 19 Jul 1987
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
BACTERIA
METABOLISM
GLUTAMIC ACID
AMINO ACIDS
ASPARTIC ACID
CARBON 14 COMPOUNDS
MALIC ACID
NITROGEN FIXATION
RESPIRATION
SUCCINIC ACID
THIN-LAYER CHROMATOGRAPHY
TRACER TECHNIQUES
CARBOXYLIC ACIDS
CHROMATOGRAPHY
DICARBOXYLIC ACIDS
HYDROXY ACIDS
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
MICROORGANISMS
ORGANIC ACIDS
ORGANIC COMPOUNDS
SEPARATION PROCESSES
551001* - Physiological Systems- Tracer Techniques