Halomonas

Ha.lo.mo' nas . Gr. n. hals, halos salt of the sea; Gr. n. monas a unit, monad; M.L. fem. n. Halomonas salt(‐tolerant) monad. Proteobacteria / Gammaproteobacteria / Oceanospirillales / Halomonadaceae / Halomonas Straight or curved rod shaped cells, generally 0.6–0.8 × 1.6–1.9 µm . One species ( H . halodenitrificans ) presents coccoid cells. Species may form elongated, flexuous filaments under certain conditions. Endospores are not formed. Gram negative. Rod shaped species are motile by lateral, polar, or peritrichous flagella. Colonies are white or yellow, turning light brown with age. Possess a mainly respiratory type of metabolism with oxygen as the terminal electron acceptor . Some species are also capable of anaerobic growth in the presence of nitrate. Some species have been reported to grow under anaerobic conditions in the absence of nitrate if supplied with glucose (but not other carbohydrates or amino acids). Nitrate is reduced to nitrite; nitrogen gas is not formed. All species tested are catalase positive; 17 of the 21 known species are also oxidase positive. Chemoorganotrophic. Carbohydrates, amino acids, polyols, and hydrocarbons can serve as sole carbon sources in mineral media. Ammonium sulfate can serve as a sole nitrogen source. Intracellular granules are not produced. Halotolerant (also described as slight to moderate halophiles), able to grow in NaCl concentrations ranging from 0.1–32.5 % ( w/v ). The major respiratory quinone is ubiquinone 9. The major fatty acids are C 16:1 , C 17:0 cyc , C 16:0 , C 18:1 , and C 19:0 cyc . In addition to having the signature sequences found in the Halomonadaceae, Halomonas species contain the following four signature bases (by E . coli numbering): C at position 1424, U at position 1439, A at position 1462, and C at position 1464. Isolated from saline environments around the world , including solar salt facilities, intertidal estuaries, the open ocean, and hypersaline lakes (Dead Sea, Israel; Organic Lake, Antarctica). The mol % G + C of the DNA is : 52–68. Type species : Halomonas elongata Vreeland, Litchfield, Martin and Elliot 1980, 495.