Characterization of iron uptake in the magnetic bacterium Aquaspirillum sp. AMB-1

The aim of this work is to elucidate the iron uptake mechanism in the magnetic bacterium Aquaspirillum sp. AMB-1, which can utilize a wide variety of iron chelates. However, no siderophore could be detected in spent culture. A 400-bp DNA fragment was amplified by polymerase chain reaction (PCR) from the genomic DNA of AMB-1, using primers designed from the sfuC gene of Serratia marcescens. This gene encodes a nucleotide binding protein in the periplasmic binding protein (PBP) dependent iron transport system. The amplified fragment was homologous with the conserved sequence of sfuC. Our results suggest that a nucleotide binding protein mediated iron transport system similar to that observed in Serratia marcescens is present in Aquaspirillum sp. AMB-1.