title: Caldimonas hydrothermale sp. nov., a novel thermophilic bacterium isolated from Roman hot bath in south Tunisia.
abstract: A polyphasic approach was used to characterize a bacterium, HAN-85(T), isolated from thermal water in natural thermal spring at Tozeur, an oasis in southwest Tunisia. The novel isolate was thermophilic, strictly aerobic and amylolytic bacterium, which stained Gram negative. Cells were short rods motile by means of a single polar flagellum. Their optimum temperature and pH required for growth were 55 degrees C and pH 7, respectively. Comparative 16S rRNA gene sequence analyses showed that strain HAN-85(T) belonged to the genus Caldimonas, with highest sequence similarity to the type strains Caldimonas manganoxidans and Caldimonas taiwanensis. DNA-DNA hybridization measurements revealed low DNA relatedness (35.2-44.5%) between the novel isolate and its closest relative, C. manganoxidans. The major cellular fatty acid components were 16:0, 17:0 cyclo and summed feature 3. The DNA G+C content was 68.3 mol%. Taken together, the results of DNA-DNA hybridization, fatty acids profile, physiological tests and biochemical analyses have allowed the genotypic and phenotypic differentiation of the isolate from currently recognized Caldimonas species. Therefore, we suggest that this isolate is a novel species within the genus Caldimonas and propose that it should be named Caldimonas hydrothermale sp. nov. The type strain is HAN-85(T) (=DSM 18497(T) =LMG 23755(T)).
authors.affiliation: Laboratoire de Biochimie et Biologie Moléculaire, Faculté des Sciences de Tunis, Campus Universitaire El-Manar, 2092 Tunis, Tunisie. hanenebouraoui@yahoo.fr
authors.forename: Hanene
authors.initials: H
authors.lastname: Bouraoui
authors.forename: Imen
authors.initials: I
authors.lastname: Boukari
authors.forename: Jean Pierre
authors.initials: JP
authors.lastname: Touzel
authors.forename: Michael
authors.initials: M
authors.lastname: O'Donohue
authors.forename: Mohamed
authors.initials: M
authors.lastname: Manai
mesh_terms: D000332:Aerobiosis; D001482:Base Composition; D042621:Comamonadaceae / Q000145:classification* / Q000166:cytology / Q000302:isolation & purification* / Q000502:physiology; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D005227:Fatty Acids / Q000032:analysis; D020459:Genes, rRNA; D005838:Genotype; D045482:Hot Springs / Q000382:microbiology*; D006358:Hot Temperature; D008969:Molecular Sequence Data; D010802:Phylogeny; D013696:Temperature; D014416:Tunisia
chemical_list: D004269:DNA, Bacterial; D005227:Fatty Acids