Pseudomonas aeruginosa reverse diauxie is a multidimensional, optimized, resource utilization strategy.

Area of Science:

• Microbial Ecology
• Systems Biology
• Bacterial Physiology

Background:

• Pseudomonas aeruginosa is a widespread opportunistic pathogen implicated in numerous infections.
• Unlike model organisms, P. aeruginosa exhibits an atypical carbon catabolite repression (CCR) strategy, diverging from classic diauxie and overflow metabolism.
• This unique metabolic behavior contributes to its ecological success but remains poorly understood.

Purpose of the Study:

• To elucidate the metabolic strategies underlying P. aeruginosa's ecological competitiveness and virulence.
• To quantify the carbon catabolite repression (CCR) strategy, termed 'reverse diauxie', employed by P. aeruginosa.
• To investigate the ecological basis and predictive modeling of reverse diauxie.

Main Methods:

• Utilized a combination of physiological experiments, omics data, and in silico analyses.
• Employed a genome-scale metabolic model of P. aeruginosa, validated with in vitro omics data.
• Applied a multidimensional strategy to predict metabolic phenotypes, contrasting with standard growth-rate maximization criteria.

Main Results:

• Identified an ecological basis for reverse diauxie in P. aeruginosa.
• Predicted a preference for lower-energy, non-fermentable carbon sources (e.g., acetate, succinate) over glucose.
• Demonstrated that maximizing growth rate alone does not predict observed reverse diauxie phenotypes.
• Showed that reverse diauxie minimizes resource investment in central metabolism while ensuring complete substrate oxidation.

Conclusions:

• Reverse diauxie is a key metabolic strategy enabling P. aeruginosa's broad distribution and virulence.
• This strategy involves efficient substrate utilization and resource investment optimization.
• Understanding reverse diauxie offers insights into P. aeruginosa's interactions within microbial communities, including potential mutualistic relationships.