Shewanella frigidimarina strain NCIMB 400 is a marine bacterium of the gamma subgroup of proteobacteria. It was isolated from the North Sea, off the coast of Aberdeen (UK), and exhibits a high degree of respiratory flexibility [1,2]. Substrates that can be used as electron acceptors in include nitrate, nitrite, trimethylamine N-oxide, Fe(III) and Mn(IV). The organism is rich in c-type cytochromes, the synthesis of many of which appears to be increased during anaerobic growth with ferric irons present as respiratory electron acceptor [3]. The S. frigidimarina species group has a number of representatives that form a clear clade in a Shewanella phyologenetic tree based on 16s rDNA gene sequences [2,4]. Other strains of this species, which are phsychrotrophic and halotolerant, have been isolated from Antarctic sea-ice and have a 40-43 mol% G+C content [4]. Biochemical studies of S. frigidimarina NCIMB 400 have revealed genes for two distinct soluble fumarate reductases and crystal structures of encoded proteins have been determined [5,6]. This organism has also been a key target for the study of the biochemistry and genetic regulation of Fe(III) respiration [3].

References:
[1] Lee JV, Gibson DM, Shewan JM (1977) A numerical taxonomic study of some Pseudomonas-like marine bacteria. Journal of General Microbiology 98,439-451
[2] Reid GA and Gordon EHJ (1999) Phylogeny of marine and freshwater Shewanella: reclassification of Shewanella putrefaciens NCIMB 400 as Shewanella frigidimarina. International Journal of Systematic Bacteriology 49,189-191.
[3] Reyes-Ramirez F, Sawers RG, Richardson DJ (2003) Characterisation of the transcriptional regulation of Shewanella frigidimarina iron-induced flavocytochrome c reveals a novel iron-responsive gene regulation system. Journal of Bacteriology 185,4564-4571
[4] Bowman JP, McCammon SA, Nichols DS, Skerratt JH, Rea SM, Nichols PD, McMeekin TA (1997) Shewanella gelidimarina sp. nov. and Shewanella frigidimarina sp. nov., novel Antarctic species with the ability to produce eicosapentaenoic acid (20:5 omega 3) and grow anaerobically by dissimilatory Fe(III) reduction. International Journal of Systematic Bacteriology 47,1040-7.
[5] Bamford V, Dobbin PS, Richardson DJ, Hemmings AM (1999) The high resolution X-ray structure of the open form of a flavocytochrome c3. Nature Structural Biology 6,1104-1107.
[6] Taylor P, Pealing SL, Reid GA, Chapman SK, Walkinshaw MD (1999) Structural and mechanistic mapping of a unique fumarate reductase. Nature Structural Biology 6,1108-12.