INFLUENCE OF GROWTH-RATE AND NUTRIENT LIMITATION ON MONOBACTAM PRODUCTION AND PEPTIDOGLYCAN SYNTHESIS IN PSEUDOMONAS-AERUGINOSA

The effects of growth rate and nutrient limitation on monobactam production, peptidoglycan content and mean cell length in Pseudomonas aeruginosa was studied using continuous culture techniques. All three parameters increased progressively with growth rate, a greater response being shown under carbon limitation compared to that occurring under nitrogen limiting conditions. interestingly, monobactum production mirrored peptidoglycan synthesis. In addition, the monobactam exhibited a broad rang of antibacterial activity and bound preferentially to PBP 1A in the producing organism. Moreover, addition of the monobactam to a growing culture inhibited cell wall synthesis. These results are discussed in relation to the control and regulation of peptidoglycan synthesis.