Radiorespirometry evidence for the discrimination between 13C-enriched glucose and unlabelled glucose molecules by...

Area of Science:

• Microbiology
• Biochemistry
• Isotope Tracing

Background:

• Paracoccus denitrificans is a bacterium known for its metabolic versatility.
• Understanding microbial metabolism is crucial for various biotechnological applications.
• Isotope labeling provides a powerful tool to elucidate metabolic pathways.

Purpose of the Study:

• To investigate the impact of 13C-enriched glucose on the glucose oxidation metabolism of Paracoccus denitrificans.
• To compare carbon dioxide (CO2) evolution rates using 14C-labeled glucose in bacteria grown on labeled versus unlabeled glucose.

Main Methods:

• Cultivating Paracoccus denitrificans with unlabeled glucose, [1-13C]glucose, or [6-13C]glucose as the sole carbon source.
• Incubating the grown cells with various 14C-glucose substrates (e.g., [1-14C]-, [6-14C]-, [U-14C]glucose).
• Measuring and comparing the rates and yields of 14CO2 evolution.

Main Results:

• Cells grown on 13C-enriched glucose exhibited significantly higher 14CO2 evolution rates compared to those grown on unlabeled glucose.
• Percentage yields of 14CO2 were substantially greater in cells adapted to 13C-glucose.
• The metabolic fate of 14C-glucose differed notably between bacteria grown on labeled and unlabeled substrates.

Conclusions:

• Growth of Paracoccus denitrificans on 13C-enriched glucose alters its subsequent 14C-glucose oxidation metabolism.
• Isotope enrichment influences microbial metabolic pathways, affecting substrate utilization and CO2 production.
• This study highlights the sensitivity of microbial metabolism to substrate isotopic composition.