title: A new lineage of halophilic, wall-less, contractile bacteria from a brine-filled deep of the Red Sea.
abstract: A novel strictly anaerobic bacterium designated strain SSD-17B(T) was isolated from the hypersaline brine-sediment interface of the Shaban Deep, Red Sea. Cells were pleomorphic but usually consisted of a central coccoid body with one or two "tentacle-like" protrusions. These protrusions actively alternated between a straight, relaxed form and a contracted, corkscrew-like one. A peptidoglycan layer was not detected by electron microscopy. The organism forms "fried-egg"-like colonies on MM-X medium. The organism is strictly anaerobic and halophilic and has an optimum temperature for growth of about 30 to 37 degrees C and an optimum pH of about 7. Nitrate and nitrite are reduced; lactate is a fermentation product. The fatty acid profile is dominated by straight saturated and unsaturated chain compounds. Menaquinone 4 is the major respiratory quinone. Phylogenetic analysis demonstrated strain SSD-17B(T) represents a novel and distinct lineage within the radiation of the domain Bacteria. The branching position of strain SSD-17B(T) was equidistant to the taxa considered to be representative lineages of the phyla Firmicutes and Tenericutes (with its sole class Mollicutes). The phenotypic and phylogenetic data clearly show the distinctiveness of this unusual bacterium, and we therefore propose that strain SSD-17B(T) (= DSM 18853 = JCM 14575) represents a new genus and a new species, for which we recommend the name Haloplasma contractile gen. nov., sp. nov. We are also of the opinion that the organism represents a new order-level taxon, for which we propose the name Haloplasmatales.
authors.affiliation: Centro de Neurociências e Biologia Celular, Department of Zoology, University of Coimbra, Coimbra, Portugal.
authors.forename: André
authors.initials: A
authors.lastname: Antunes
authors.forename: Fred A
authors.initials: FA
authors.lastname: Rainey
authors.forename: Gerhard
authors.initials: G
authors.lastname: Wanner
authors.forename: Marco
authors.initials: M
authors.lastname: Taborda
authors.forename: Jürgen
authors.initials: J
authors.lastname: Pätzold
authors.forename: M Fernanda
authors.initials: MF
authors.lastname: Nobre
authors.forename: Milton S
authors.initials: MS
authors.lastname: da Costa
authors.forename: Robert
authors.initials: R
authors.lastname: Huber
mesh_terms: D000693:Anaerobiosis; D000818:Animals; D001156:Artemia / Q000382:microbiology*; D004269:DNA, Bacterial / Q000032:analysis / Q000737:chemistry / Q000235:genetics; D006094:Gram-Positive Bacteria / Q000145:classification* / Q000235:genetics; D008969:Molecular Sequence Data; D010802:Phylogeny; D012623:Seawater / Q000382:microbiology*
chemical_list: D004269:DNA, Bacterial