A polyphosphate kinase 1 (ppk1) mutant of Pseudomonas aeruginosa exhibits multiple ultrastructural and functional defects.

Pseudomonas aeruginosa, of medical, environmental, and industrial importance, depends on inorganic polyphosphate (poly P) for a wide range of functions, especially survival. Mutants of PAO1 lacking poly P kinase 1, PPK1, the enzyme responsible for most poly P synthesis in Escherichia coli and other bacteria, are defective in motility, quorum sensing, biofilm formation, and virulence. We describe here multiple defects in the ppk1 mutant PAOM5, including a striking compaction of the nucleoid, distortion of the cell envelope, lack of planktonic motility and exopolymer production, and susceptibility to the beta-lactam antibiotic carbenicillin as well as desiccation.

Mouse embryonic stem cell colonisation of carbonated apatite surfaces.

Apatites play a crucial role in the body and have been used extensively in biomedical implants. The influence on stem cell behaviour is not known and so this study will explore whether sintered carbonated apatites are favourable for propagation of stem cells. Different weight substitutions of carbonated apatite, specifically 2.