title: Haloferax elongans sp. nov. and Haloferax mucosum sp. nov., isolated from microbial mats from Hamelin Pool, Shark Bay, Australia.
abstract: Extremely halophilic archaea were cultivated from smooth and pustular microbial mats collected from Hamelin Pool, Shark Bay, Western Australia. On the basis of morphology, two phenotypes were present and 16S rRNA gene sequence analysis indicated that all strains were most closely related to members of the genus Haloferax (98.1-99.4 % similarity). One representative strain from each phenotype was selected for further taxonomic characterization. Strain SA5T, isolated from the smooth mat, formed small ( approximately 1 mm diameter), red, translucent colonies on agar medium and strain PA12T, isolated from the pustular mat, formed large (3-5 mm diameter), pink, mucoid, domed colonies. Both strains grew in media with 1.7-5.1 M NaCl, required at least 0.2 M Mg2+ for growth and had pH optima of 7.4. The 16S rRNA gene similarity between strains SA5T and PA12T was 97.1 %. Physiological properties, G+C content and polar lipid composition supported placement of both strains in the genus Haloferax. Phenotypic analysis indicated that the two strains were distinct from each other and from all other members of the genus. This was confirmed by the low DNA-DNA relatedness between strains SA5T and PA12T (18-30 %) and between both strains and all other recognized Haloferax species. Two novel species of the genus Haloferax are proposed to accommodate these novel isolates, Haloferax elongans sp. nov. (type strain SA5T=JCM 14791T=ATCC BAA-1513T=UNSW 104100T) and Haloferax mucosum sp. nov. (type strain PA12T=JCM 14792T=ATCC BAA-1512T=UNSW 104200T).
authors.affiliation: School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW 2052, Australia.
authors.forename: Michelle A
authors.initials: MA
authors.lastname: Allen
authors.forename: Falicia
authors.initials: F
authors.lastname: Goh
authors.forename: Stefan
authors.initials: S
authors.lastname: Leuko
authors.forename: Akinobu
authors.initials: A
authors.lastname: Echigo
authors.forename: Toru
authors.initials: T
authors.lastname: Mizuki
authors.forename: Ron
authors.initials: R
authors.lastname: Usami
authors.forename: Masahiro
authors.initials: M
authors.lastname: Kamekura
authors.forename: Brett A
authors.initials: BA
authors.lastname: Neilan
authors.forename: Brendan P
authors.initials: BP
authors.lastname: Burns
mesh_terms: D001482:Base Composition; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D005798:Genes, Bacterial; D019621:Haloferax / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D008055:Lipids / Q000032:analysis; D008969:Molecular Sequence Data; D010641:Phenotype; D010802:Phylogeny; D012329:RNA, Bacterial / Q000235:genetics; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012623:Seawater / Q000382:microbiology; D012689:Sequence Homology, Nucleic Acid; D013045:Species Specificity; D014904:Western Australia
chemical_list: D004269:DNA, Bacterial; D008055:Lipids; D012329:RNA, Bacterial; D012336:RNA, Ribosomal, 16S