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Position-specific metabolic tracer probing of soil metabolic networks (1 of 4) - Substrate

Dijkstra, Paul and Heinrich, Paul L and Hungate, Bruce A (2010) Position-specific metabolic tracer probing of soil metabolic networks (1 of 4) - Substrate. [Dataset]

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In order to study controls on metabolic processes in soils, we determined the dynamics of 13CO2 production from two position-specific 13C-labeled pyruvate isotopologues in the presence and absence of glucose, succinate, pine, and legume leaf litter, and under anaerobic conditions. We observed that the C from the carboxyl group (C1) of pyruvate was lost as CO2 much faster than its other C atoms (C2,3). Addition of glucose, pine and legume leaf litter reduced the ratio between 13CO2 production from 1-13C pyruvate and 2,3-13C pyruvate (C1/C2,3 ratio), whereas anaerobic conditions increased this ratio. We interpret a low C1/C2,3 ratio as an indication of increased Krebs cycle activity in response to carbon inputs, while a higher ratio implies a reduced Krebs cycle activity in response to anaerobic conditions. Succinate, a gluconeogenic substrate, reduced 13CO2 production from pyruvate to near zero, likely reflecting increased carbohydrate biosynthesis from Krebs cycle intermediates. The difference in 13CO2 production rate from pyruvate isotopologues disappeared 4-5 days after pyruvate addition, indicating that C positions were scrambled by ongoing soil microbial transformations. This work demonstrates that metabolic tracers such as pyruvate can be used to determine qualitative aspects of C flux patterns through metabolic pathways of soil microbial communities.

Item Type: Dataset
Publisher’s Statement: Creative Commons CC BY-NC-SA
Keywords: Stable isotopes; Carbon; C and N availability; Soil microbial biomass; C metabolism
Subjects: G Geography. Anthropology. Recreation > GE Environmental Sciences
Q Science > QH Natural history > QH301 Biology
NAU Depositing Author Academic Status: Faculty/Staff
Department/Unit: College of Engineering, Forestry, and Natural Science > Biological Sciences
Research Centers > Merriam-Powell Center for Environmental Research
Date Deposited: 22 Dec 2015 18:46
URI: http://openknowledge.nau.edu/id/eprint/2250

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