Glucose Metabolism in Sediments of a Eutrophic Lake: Tracer Analysis of Uptake and Product Formation †
AUTOR(ES)
King, Gary M.
RESUMO
The uptake of glucose and the formation of end products from glucose catabolism have been measured for sediments of eutrophic Wintergreen Lake with a combination of tritiated and 14C-labeled tracers. Time course analyses of the loss of [3H]glucose from sediments were used to establish rate constants for glucose uptake at natural substrate concentrations. Turnover times from these analyses were about 1 min for littoral and profundal sediments. No seasonal or site differences were noted in turnover times. Time course analyses of [U-14C]glucose uptake and 14C-labeled end product formation indicated that glucose mass flow could not be calculated from end product formation since the specific activity of added [14C]glucose was significantly diluted by pools of intracellular glucose and glucose metabolites. Mass flow could only be accurately estimated by use of rates of uptake from tracer studies. Intermediate fermentation end products included acetate (71%), propionate (15%), lactate (9%), and only minor amounts of butyrates or valerates. Addition of H2 to sediments resulted in greater production of lactate (28%) and decreased formation of acetate (50%), but did not affect glucose turnover. Depth profiles of glucose uptake indicated that rates of uptake decreased with depth over the 0- to 18-cm interval and that glucose uptake accounted for 30 to 40% of methanogenesis in profundal sediments.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=242189Documentos Relacionados
- Intermediary Metabolism of Organic Matter in the Sediments of a Eutrophic Lake †
- Reduction of Sulfur Compounds in the Sediments of a Eutrophic Lake Basin †
- Comparative Aspects of Sulfur Mineralization in Sediments of a Eutrophic Lake Basin †
- Electron Donors Utilized by Sulfate-Reducing Bacteria in Eutrophic Lake Sediments †
- Glucose Uptake and End Product Formation in an Intertidal Marine Sediment †