Marinospirillum celere sp. nov., a novel haloalkaliphilic, helical bacterium isolated from Mono Lake

Abstract

Two strains of a Gram-negative, helical, haloalkaliphilic bacterium were isolated from Mono Lake (USA). Both strains were mesophilic and grew between 13 and 55 degrees C, with optimum growth at 35-45 degrees C. The optimum pH for growth was 9.5. Growth was observed at NaCl concentrations of 0.5-12% (w/v), with optimum growth at 2% NaCl. Both isolates were motile by means of bipolar tuft flagella, coccoid body-forming and strictly aerobic. It was concluded that they belong to the same species, based on DNA-DNA hybridization values (95% DNA relatedness). DNA G+C contents of the novel strains were 52.1 and 52.3 mol%. On the basis of 16S rRNA gene sequence similarity, both strains were shown to be related closely to the members of the genus Marinospirillum (family Oceanospirillaceae, class Gammaproteobacteria). Sequence similarity of strain v1c_Sn-redT to the type strains of Marinospirillum alkaliphilum, Marinospirillum minutulum, Marinospirillum megaterium and Marinospirillum insulare was 95.0, 92.7, 91.8 and 91.8%, respectively. Chemotaxonomic data [major ubiquinone, Q8; major fatty acids, C18:1(n-7) and C16:0] and physiological and biochemical tests supported the affiliation of the novel strains to the genus Marinospirillum as members of a novel species, for which the name Marinospirillum celere sp. nov. is proposed, with the type strain v1c_Sn-redT (=LMG 24610T=VKM 2416T).