title: Comparative phylogenetic analyses of Halomonas variabilis and related organisms based on 16S rRNA, gyrB and ectBC gene sequences.
abstract: Halomonas variabilis and phylogenetically related organisms were isolated from various habitats such as Antarctic terrain and saline ponds, deep-sea sediment, deep-sea waters affected by hydrothermal plumes, and hydrothermal vent fluids. Ten strains were selected for physiological and phylogenetic characterization in detail. All of those strains were found to be piezotolerant and psychrotolerant, as well as euryhaline halophilic or halotolerant. Their stress tolerance may facilitate their wide occurrence, even in so-called extreme environments. The 16S rDNA-based phylogenetic relationship was complemented by analyses of the DNA gyrase subunit B gene (gyrB) and genes involved in the synthesis of the major compatible solute, ectoine: diaminobutyric acid aminotransferase gene (ectB) and ectoine synthase gene (ectC). The phylogenetic relationships of H. variabilis and related organisms were very similar in terms of 16S rDNA, gyrB, and ectB. The ectC-based tree was inconsistent with the other phylogenetic trees. For that reason, ectC was inferred to derive from horizontal transfer.
authors.affiliation: School of Biosphere Sciences, Hiroshima University, Higashi-hiroshima, Japan.
authors.forename: Takuji
authors.initials: T
authors.lastname: Okamoto
authors.forename: Akihiko
authors.initials: A
authors.lastname: Maruyama
authors.forename: Satoshi
authors.initials: S
authors.lastname: Imura
authors.forename: Haruko
authors.initials: H
authors.lastname: Takeyama
authors.forename: Takeshi
authors.initials: T
authors.lastname: Naganuma
mesh_terms: D000220:Adaptation, Biological; D015373:Bacterial Typing Techniques; D003080:Cold Temperature; D027081:DNA Gyrase / Q000235:genetics; D004269:DNA, Bacterial / Q000737:chemistry / Q000302:isolation & purification; D004275:DNA, Ribosomal / Q000737:chemistry / Q000302:isolation & purification; D022761:Gene Transfer, Horizontal; D005798:Genes, Bacterial; D020459:Genes, rRNA; D019015:Geologic Sediments / Q000382:microbiology; D020632:Halomonas / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification / Q000502:physiology; D006836:Hydro-Lyases / Q000235:genetics; D006874:Hydrostatic Pressure; D008969:Molecular Sequence Data; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics*; D012623:Seawater / Q000382:microbiology; D017422:Sequence Analysis, DNA; D017385:Sequence Homology; D012965:Sodium Chloride; D000637:Transaminases / Q000235:genetics; D014871:Water Microbiology
chemical_list: D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D012336:RNA, Ribosomal, 16S; D012965:Sodium Chloride; D000637:Transaminases; D006836:Hydro-Lyases; C106231:ectoine synthase; D027081:DNA Gyrase