Labeling of carbon pools in Bradyrhizobium japonicum bacteroids in intact nodules following feedings of sup 14 CO sub 2 for periods of <= six minutes
- Ohio State Univ., Wooster (United States)
A system was established for isolation of bacteroids from soybean nodules in 5 min by centrifugation of crude brei through silicone oil in a microfuge. Using marker enzymes {Beta}-hydroxybutyrate dehydrogenase (DH) and cytochrome C oxidase, it was found that bacteroids were not ruptured during isolation, that mitochondrial contamination was {<=} 2%, and that bacteroid recovery was {approx} 93%. About 40 {mu}Ci {sup 14}CO{sub 2} were supplied to 300 mg fresh wt of intact nodules to label the 4-carbon acid pools in the host cytoplasm of infected cells. Following incubations of 1 to 6 min label in the cytosol was largely in malate (MAL), as expected. Label in aspartate and citrate was about 20% that in MAL. {sup 14}C in succinate (SUC) was only {approx} 3% of that in MAL, and fumarate was essentially unlabeled indicating limited equilibration of label via fumarase and SUC DH. In bacteroids MAL was most rapidly labeled, but glutamate {sup 14}C was about 50% that in MAL; this is consistent with other results. Aspartate and alanine were labeled at a rate approx 10% that of MAL, and SUC, citrate and fumarate were slowly labeled. Results are consistent with 4-carbon acids (mainly malate) as the main source of reduced carbon for bacteroids.
- OSTI ID:
- 5562492
- Report Number(s):
- CONF-9107184--
- Journal Information:
- Plant Physiology, Supplement; (United States), Journal Name: Plant Physiology, Supplement; (United States) Vol. 96:1; ISSN PPYSA; ISSN 0079-2241
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
59 BASIC BIOLOGICAL SCIENCES
ALANINES
AMINO ACIDS
ASPARTIC ACID
BACTERIA
CARBON 14 COMPOUNDS
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON OXIDES
CARBOXYLIC ACIDS
CHALCOGENIDES
CYTOCHROME OXIDASE
DICARBOXYLIC ACIDS
ENZYMES
FUMARIC ACID
GLUTAMIC ACID
GLYCINE HISPIDA
HAEM DEHYDROGENASES
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
LEGUMINOSAE
MAGNOLIOPHYTA
MAGNOLIOPSIDA
MALEIC ACID
METABOLISM
MICROORGANISMS
ORGANIC ACIDS
ORGANIC COMPOUNDS
OXIDES
OXIDOREDUCTASES
OXYGEN COMPOUNDS
PLANTS
PROTEINS
RHIZOBIUM
SUCCINIC ACID
TRACER TECHNIQUES