Related Experiment Videos
Pseudomonas cepacia mutants blocked in the Entner-Doudoroff pathway
Journal of Bacteriology
|June 1, 1982
Summary
Pseudomonas cepacia mutants lacking key enzymes in the Entner-Doudoroff pathway cannot metabolize glucose or gluconate. However, some mutants adapt to utilize gluconate via the pentose shunt, suggesting metabolic flexibility.
Area of Science:
- Microbiology
- Bacterial Metabolism
- Enzymology
Background:
- Pseudomonas cepacia possesses 6-phosphogluconate dehydrogenase (6PGAD), suggesting pentose shunt activity.
- The Entner-Doudoroff pathway is crucial for glucose and gluconate metabolism in many bacteria.
Purpose of the Study:
- To investigate the roles of 6-phosphogluconate (6PGA) dehydratase (Edd) and 2-keto-3-deoxy-6-phosphogluconate (KDPG) aldolase (Eda) in P. cepacia's carbohydrate utilization.
- To understand the regulation and induction of these enzymes.
Main Methods:
- Generation and characterization of Edd- and Eda- P. cepacia mutants.
- Growth studies using various carbon sources, including glucose, gluconate, and glucuronic acid.
- Analysis of enzyme induction by 6PGA and gluconate.
Main Results:
- Edd- and Eda- mutants failed to utilize glucose and gluconate.
- Eda- mutants could still degrade glucuronic acid, unlike in E. coli.
- Both Edd and Eda enzymes were inducible by 6PGA.
- Mutants accumulated toxic levels of 6PGA or KDPG when grown on inhibitory carbohydrates with alternate carbon sources.
- Certain Edd- mutants adapted to grow on gluconate by upregulating 6PGAD, utilizing the pentose shunt.
Conclusions:
- The Entner-Doudoroff pathway is essential for glucose and gluconate metabolism in P. cepacia.
- P. cepacia exhibits metabolic plasticity, with potential for pentose shunt adaptation for gluconate utilization.
- 6PGA accumulation is toxic to P. cepacia, leading to growth inhibition.