Nitrosococcus oceani ATCC 19707

Nitrosococcus oceani, formerly known as Nitrosocystis oceanus, is a Gram-negative ammonia-oxidizing bacterium isolated from seawater. It is an obligate chemolithoautotroph capable of extracting energy and reducing power from the oxidation of ammonia to nitrite. In contrast to betaproteobacterial nitrifer genomes, it contains two complete rrn operons that belong to different classes. Several blocks of genes that were identified as putatively phage related, indicating that N.oceani has been a frequent target for bacteriophage in the ocean. It contains the genes coding for the biosynthesis of the 20 amino acids. Twenty aminoacyl-tRNA synthetases were identified, including two forms of LysRS and two distinct forms of GlxRS but AsnRS and GlnRS were missing. At least 22 genes involved in iron transport have been identified. Two genes coding for Fur are present. Several uptake systems for other inorganic ions are present. Several sodium/hydrogen antiporters have been found; they play an important role in maintaining intracellular pH and conferring salt tolerance. Nitrosococcus oceani has several protein export and secretion systems, including a preprotein translocase, genes coding gor the TatABC system, as well as genes coding for the type II general secretion/pilus synthesis pathway and genes coding for the type IV conjugal DNA/protein transfer system. It has a cluster of genes encoding parts of a PTS-type sugar transport system. It encodes a form I RuBisCO. N.oceani flagellation and motility genes are arranged in two large clusters. The master switch operon flhCD seems to be missing. N.oceani seems to have only a limited chemotactic activity because only one methyl-accepting chemotaxis protein was identified. A large number of complete two-component systems has been identified. It contains a limited inventory contributing to stress tolerance and oxidative stress tolerance, respectively. (EBI Integr8)