Effects of vitamin B12 on the gene expression of PAO1 under anaerobic growth conditions

Pseudomonas aeruginosa undergoes cell elongation and forms robust biofilms during anaerobic respiratory growth using nitrate (NO3-) as an alternative electron acceptor. Understanding the mechanism of cell shape change induced upon anaerobiosis is crucial to the development of effective treatments against P. aeruginosa biofilm infection. Anaerobic growth of PAO1 reached higher cell density in the presence of vitamin B12, an essential coenzyme of class II ribonucleotide reductase. In addition, cell morphology returned to a normal rod shape. These results suggest that vitamin B12, the production of which was suppressed during anaerobic growth, can restore cellular machineries for DNA replication and therefore facilitate better anaerobic growth of P. aeruginosa with normal cell division. We used microarray to elucidate the global gene expression profiles underlying vitamin B12-induced changes in bacterial cell shape and growth-associated properties. Gene expression profiles of PAO1 grown in LBN (LB+NO3-) or LBN supplemented with 1 microM vitamin B12 are compared.