Congregibacter litoralis

KT71 was first isolated from a surface water sample taken near Helgoland, an island in the North Sea by Eilers et al. in August 1999.[1] To isolate the organism, Eliers et al. used direct plating on complex low-nutrient media called MPM developed by Schut et al.[1][4] MPM was designed to mimic seawater. However, Eilers et al. modified this to adjust the pH to 7.5 and reduced NH₄Cl and KH₂PO₄ to 50 and 1.5 μM, respectively.[1] Briefly, seawater was plated onto MPM and modified MPM and allowed to grow for 37 days. During the 37 days, colonies were picked and placed into liquid MPM culture.[1]

In 2004, C. litoralis KT71 was picked for whole genome sequencing.[2] To sequence the organism, plasmid and fosmid libraries were prepared with insert sizes of 4 and 40 kb. The clonal sequences were sequenced by an Applied Biosystems 3730XL DNA sequencer at the J. Craig Venter Science Foundation Joint Technology Center. From this, it was determined that C. litoralis KT71 had a genome size of 4.35Mbp with a GC content of 57.7%.[1] Moreover, the genome contains 3933 coding genes.[2] KT71's assembled genome was assessed for protein coding regions using the Prokaryotic Genomes Automatic Annotation Pipeline (PGAAP) from the National Center for Biotechnology Information.[7] Once completed, genome annotation of the open reading frames was done with GenDB v2.2 annotation system.[7]

Congregibacter litoralis KT71 is an aerobic anoxygenic photoheterotroph (AAnPs).[2][8] In general terms, this means that KT71 is a strict aerobic organism with preference for low-oxygen environments. To find these environments, KT71 uses a flagellum combined with chemotaxis to move towards low-oxygen areas.[2] Though it does contain a complete photosynthesis superoperon, KT71 cannot grow autotrophically.[2][8] Instead, KT71 uses light for light-dependent cyclic electron transport through its photosystem to generate a proton gradient.[2][8] To determine the metabolism of KT71, the organism was grown in mineral medium containing: 35.0 g of sea salts, 0.1 g of NH₄Cl, 0.05 g of K₂HPO₄, and 10 ml of a vitamin solution.[7] The mineral medium was then supplemented with various carbon compounds to determine the ability for KT71 to use in its metabolism.[7][8] From this it was determined that KT71 can grow well with carbon sources such as glutamate, pyruvate, and fatty acids as well as more complex substrates like yeast extract and trypticase peptone.[7][8] Within its genome, genes, determined from genome annotation, involved in the pentose phosphate pathway, trichloroacetic acid cycle (TCA), citric acid cycle were found which correlated to the metabolism observed in culture.[2][8] Further, KT71 is unable to use glucose as a sole carbon source, which was supported by genome analysis that showed a lack of glucose metabolism genes.[2] Although the supplementation of inorganic sulfur to media did not promote growth, KT71 does contain sulfur-oxidizing (sox) genes that are uniquely arranged in its genome.[2] It is predicted that the potential use of the sox genes would be in the adenosine 5'-phosphosulfate (APS)/ 3'-Phosphoadenosine-5'-phosphosulfate (PAPS) pathway.[2][7]

• Type strain of Congregibacter litoralis at BacDive - the Bacterial Diversity Metadatabase