Marinococcus halotolerans sp. nov., isolated from Qinghai, north-west China Wen-Jun Li, 1 Peter Schumann, 2 Yu-Qin Zhang, 1 Guo-Zhong Chen, 1 Xin-Peng Tian, 1 Li-Hua Xu, 1 Erko Stackebrandt 2 and Cheng-Lin Jiang 1 Correspondence Wen-Jun Li wjli@ynu.edu.cn or lihxu@ynu.edu.cn 1 The Key Laboratory for Microbial Resources of Ministry of Education, Yunnan Institute of Microbiology and Laboratory for Conservation and Utilization of Bio-Resources, Yunnan University, Kunming, Yunnan, 650091, P. R. China 2 DSMZ – Deutsche Sammlung von Mikroorganismen und Zellkulturen GmbH, Mascheroder Weg 1b, D-38124 Braunschweig, Germany An aerobic bacterium was isolated from saline soil located in Qinghai, north-west China. The bacterium, designated YIM 70157 T , was investigated using a polyphasic taxonomic approach. The Gram reaction of the organism was positive. Comparative 16S rRNA gene sequence analysis demonstrated the isolate to be a member of the genus Marinococcus, the closest phylogenetic neighbour of the unknown bacterium being Marinococcus halophilus DSM 20408 T with a similarity of 99?4 %. The peptidoglycan type of YIM 70157 T was A1c, with meso-diaminopimelic acid as diagnostic diamino acid. The major fatty acids were ai-C 15 : 0 , ai-C 17 : 0 and i-C 16 : 0 . The menaquinones were MK-7 and MK-6. The phospholipids were diphosphatidylglycerol and phosphatidylinositol. The G+C content of total DNA was 48?5 mol%. On the basis of phylogenetic and phenotypic evidence and DNA–DNA hybridization data, this isolate should be classified as a novel species of Marinococcus, for which the name Marinococcus halotolerans sp. nov. is proposed. The type strain is YIM 70157 T (=DSM 16375 T =KCTC 19045 T ). The genus Marinococcus was proposed to accommodate two species, Marinococcus albus and Marinococcus halophilus; both species were formerly classified as Planococcus species (Novitsky & Kushner, 1976; Hao et al., 1984). They have meso-diaminopimelic acid in the cell wall, a DNA G+C content ranging between 43?9 and 46?6 mol%, a menaqui- none system with MK-7, grow at a concentration of 20 % NaCl, and are motile cocci. A third Marinococcus species, Marinococcus hispanicus, has been transferred to the genus Salinicoccus (Ventosa et al., 1992). Therefore, at the time of writing, there are only two Marinococcus species with validly published names. M. halophilus is the predominant coccus found in most hypersaline environments (Ventosa et al., 1983; Ma ´rquez et al., 1992). During our investigations of the extremophilic microbial flora of China (Tang et al., 2003; Li et al., 2004a, b, 2005a, b), strain YIM 70157 T was recovered and characterized by a combination of genotypic and phenotypic methods. It was evident that the isolate was sufficiently distinct from the two species of the genus Marinococcus to warrant the descrip- tion of a novel species, for which the name Marinococcus halotolerans sp. nov. is proposed. Strain YIM 70157 T was isolated from a hypersaline soil sample, collected from Qinghai, north-west China, by using the dilution plating method. Detailed information about the saline soils and salt lakes in Qinghai Province was given by Zhang et al. (1987). Modified medium SG (Sehgal & Gibbons, 1960) used for selective isolation contained the following (g l 21 ): Casamino acids (7?5), yeast extract (10?0), trisodium citrate (3?0), NaCl (2?0), KCl (2?0), MgCl 2 .6H 2 O (250), MgSO 4 .7H 2 O (1?0), FeSO 4 .7H 2 O (0?05) and MnSO 4 .7H 2 O (0?0002). MgCl 2 .6H 2 O was sterilized sepa- rately and then added to the medium. The plate was incubated at 28 u C for 2 weeks. The isolate was maintained on modified SG agar slants that contained 10 % (w/v) MgCl 2 .6H 2 O at 4 u C and as glycerol suspensions (20 %, w/v) at 220 u C. Biomass for chemical and molecular systematic studies was obtained from enrichment agar plates of modifi- ed SG agar medium incubated at 28 uC for about 4–5 days. The morphology and motility of cells grown for 10–48 h on modified SG agar were examined by using light microscopy (model BH 2; Olympus) and transmission electron micro- scopy (model H-800; Hitachi). For transmission electron microscopy observation, cells were negatively stained with 1 % (w/v) phosphotungstic acid, after air drying. Observa- tion of flagella was also performed using the Leifson flagella staining method (Leifson, 1960). Gram staining was carried out using the standard Gram reaction combined with the Published online ahead of print on 22 April 2005 as DOI 10.1099/ ijs.0.63596-0. The GenBank/EMBL/DDBJ accession number for the 16S rRNA gene sequence of strain YIM 70157 T is AY817493. 63596 G 2005 IUMS Printed in Great Britain 1801 International Journal of Systematic and Evolutionary Microbiology (2005), 55, 1801–1804 DOI 10.1099/ijs.0.63596-0