Recombinant Pseudomonas sp. B4 that overexpressed yeast exopolyphosphatase also showed the functional deficiencies in motility and biofilm development reported for ppk1 mutants from P. aeruginosa PAO1 [21]. In addition, new structural and

functional defects such as MCC 950 changes in colony morphology, LPS structure and cellular division are reported in this communication. Finally, to study the proteomic changes that occurred during polyP deficiency recombinant strains were compared under different growth conditions and phases of growth. Interesting proteins related to energetic metabolism were overexpressed this website during polyP scarcity, such as three enzymes from the tricarboxylic acid (TCA) cycle, and one ATP synthase subunit. Protein folding, fatty acid catabolism and amino acid biosynthesis were other gene onthology (GO) categories overrepresented during polyP deficit. On the other hand, motility and transport proteins were the only categories underrepresented in this condition.

The proteomics results suggest a link between polyP and central metabolism that can be further explored to clarify the multiple structural and functional defects found during the lack of polyP in bacteria. Results Structural and functional defects in polyphosphate deficient bacteria Overexpression of PPX resembled the functional defects found in motility and biofilm formation in a ppk1 mutant from P. aeruginosa PAO [21]. Despite several MLN2238 clinical trial functional Etofibrate and structural defects have been reported in P. aeruginosa PAO1 ppk1 mutant [15, 21, 22], our polyP deficient cells showed new functional and structural phenotypes not previously reported. PPK1 is essential for biofilm development and virulence of P. aeruginosa PAO1. Considering that lipopolysaccharide

(LPS) is also very important in both cellular processes; the electrophoretic profile of LPS from recombinants Pseudomonas sp. B4 were analyzed. Interestingly, changes in the core of the LPS were observed in Tricine/SDS-polyacrylamide gel electrophoresis (Figure 1). To our knowledge, the structure of the LPS core from Pseudomonas sp. B4 has not yet been elucidated and consequently it is difficult to determine the structural nature of the change found in the LPS core. It would be interesting to determine the structure of LPS in both strains [control and polyP(-)] to reveal the change in the LPS and its probable link with polyP. Figure 1 LPS profiles of polyP-deficient cells of Pseudomonas sp . B4. Equal numbers of Pseudomonas sp. B4 polyP-deficient and control cell samples were loaded in each lane and analysed by 12% (w/v) PAGE by using a Tricine-SDS buffer system. LPS from Salmonella serovars Typhi was used as LPS control (lane M). The arrow indicates the change seen in a band of the inner core. RU: repetitive units. It was found that inorganic polyP influences not only biofilm formation but also colony morphology phenotype.