Genus Roseivivax Research Articles

Roseivivax jejudonensis sp. nov., isolated from the junction between the ocean and a freshwater spring at Jeju Island, South Korea.

A Gram-stain negative, coccoid- or oval-shaped and non-gliding bacterial strain, designated CDM-17(T), was isolated from the zone where the ocean and a freshwater spring meet at Jeju island, South Korea, and subjected to a polyphasic taxonomic study. Strain CDM-17(T) was observed to form smooth, circular, glistening, slightly convex, light yellowish pink colonies on marine agar, and was found to grow optimally at pH 7.0-8.0, at 30°C and in the presence of 2-3% (w/v) NaCl. A neighbour-joining phylogenetic tree based on 16S rRNA gene sequences showed that strain CDM-17(T) fell within the clade comprising the Roseivivax species, clustering with the type strain of Roseivivax sediminis with which it exhibited 98.3% sequence similarity value. Sequence similarities to the type strains of the other recognized Roseivivax species were 94.7-96.8%. Strain CDM-17(T) was found to contain Q-10 as the predominant ubiquinone and summed feature 8 (C18:1 ω6c and/or C18:1 ω7c) as the major fatty acid. The major polar lipids were identified as phosphatidylcholine, phosphatidylglycerol, an unidentified aminolipid, an unidentified glycolipid and an unidentified lipid. The DNA G+C content of strain CDM-17(T) was determined to be 66.2mol% and its mean DNA-DNA relatedness value with Rsv. sediminis KCTC 23444(T) was 17.5±2.7%. Differential phenotypic properties, together with the phylogenetic and genetic distinctiveness, revealed that strain CDM-17(T) is distinguishable from recognized Roseivivax species. On the basis of the data presented, strain CDM-17(T) is proposed to represent a novel species of the genus Roseivivax, for which the name Roseivivax jejudonensis sp. nov. is proposed. The type strain is CDM-17(T) (=KCTC 42110(T)=CECT 8625(T)).

Roseivivax atlanticus sp. nov., isolated from surface seawater of the Atlantic Ocean

A taxonomic study was carried out on strain 22II-S10s(T), which was isolated from the surface seawater of the Atlantic Ocean. The bacterium was found to be Gram-negative, oxidase and catalase positive, rod shaped and motile by subpolar flagella. The isolate was capable of gelatine hydrolysis but unable to reduce nitrate to nitrite or degrade Tween 80 or aesculin. Growth was observed at salinities of 0.5-18% (optimum, 2-12%), at pH of 3-10 (optimum, 7) and at temperatures of 10-41°C (optimum 28°C). Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain 22II-S10s(T) belongs to the genus Roseivivax, with highest sequence similarity to Roseivivax halodurans JCM 10272(T) (97.2%), followed by Roseivivax isoporae LMG 25204(T) (97.0%); other species of genus Roseivivax shared 95.2-96.7% sequence similarity. The DNA-DNA hybridization estimate values between strain 22II-S10s(T) and the two type strains (R. halodurans JCM 10272(T) and R. isoporae LMG 25204(T)) were 22.00 and 21.40%. The principal fatty acids were identified as Summed Feature 8 (C18:1 ω7c/ω6c) (67.4%), C18:0 (7.2%), C19:0 cyclo ω8c (7.1%), C18:1 ω7c 11-methyl (6.8%) and C16:0 (5.9%). The respiratory quinone was determined to be Q-10 (100%). Phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol, an aminolipid, a glycolipid and three phospholipids were present. The G+C content of the chromosomal DNA was determined to be 67.5mol%. The combined genotypic and phenotypic data show that strain 22II-S10s(T) represents a novel species within the genus Roseivivax, for which the name Roseivivax atlanticus sp. nov. is proposed, with the type strain 22II-S10s(T) (=MCCC 1A09150(T)=LMG 27156(T)).

Roseivivax lentus sp. nov., isolated from a tidal flat sediment, and emended description of the genus Roseivivax Suzuki et al. 1999

A Gram-negative-staining, aerobic, non-motile and rod-shaped bacterial strain, S5-5(T), was isolated from a tidal flat sediment at Saemankum on the west coast of Korea and subjected to a polyphasic taxonomic investigation. Strain S5-5(T) grew optimally at pH 7.5-8.0, at 30 degrees C and in the presence of 2 % (w/v) NaCl. It did not produce bacteriochlorophyll a. Phylogenetic analyses based on 16S rRNA gene sequences showed that strain S5-5(T) is phylogenetically closely related to the genus Roseivivax, joining the cluster comprising the two recognized Roseivivax species. The 16S rRNA gene sequence similarity between strain S5-5(T) and members of the genus Roseivivax was in the range 95.0-96.7 %. Strain S5-5(T) contained Q-10 as the predominant ubiquinone and C(18 : 1)omega7c and 11-methyl C(18 : 1)omega7c as the major fatty acids. The DNA G+C content was 68.2 mol%. Differential phenotypic properties, together with the phylogenetic distinctiveness, demonstrated that strain S5-5(T) could be differentiated from Roseivivax species. On the basis of the data presented, strain S5-5(T) is considered to represent a novel species of the genus Roseivivax, for which the name Roseivivax lentus sp. nov. is proposed. The type strain is S5-5(T) (=KCTC 22708(T) =CCUG 57755(T)).

Sediminimonas qiaohouensis gen. nov., sp. nov., a member of the Roseobacter clade in the order Rhodobacterales

Two aerobic bacterial strains, YIM B024(T) and YIM B025, were isolated from a salt mine in Yunnan, south-west China. Both strains showed almost the same physiological properties. Cells were Gram-negative, non-motile, non-spore-forming rods. The novel strains grew at 15-37 degrees C, pH 6.5-9.0 and 0.25-20 % (w/v) NaCl; optimum growth was observed at 28-30 degrees C, pH 7.0-8.5 and 1.5-10 % NaCl. Oxidase, catalase and nitrate-reducing activities were detected. The two strains were closely related to each other with a 16S rRNA gene sequence similarity of 100 %. DNA-DNA hybridization experiments revealed high relatedness values (90+/-0.4 %) between strains YIM B024(T) and YIM B025, which suggested that these two new strains constituted a single species. Phylogenetic analysis based on 16S rRNA gene sequences indicated that the two isolates formed a loose cluster with members of the genus Roseivivax in the Roseobacter clade, but were clearly separated from this genus. The levels of 16S rRNA gene sequence similarity between the two isolates and members of the genus Roseivivax ranged from 92.4 to 93.9 %. The major polar lipids comprised diphosphatidylglycerol, phosphatidylglycerol, phosphatidylcholine and four unknown phospholipids. The major cellular fatty acids were C(18 : 1)omega7c, C(16 : 0), C(18 : 1)omega9c, 11-methyl C(18 : 1)omega7c and C(19 : 0) cyclo omega8c. The sole respiratory quinone was Q-10 and the genomic DNA G+C content was 63.0-64.1 mol%. The distinct phylogenetic position and a combination of phenotypic and chemotaxonomic characteristics supported the proposal of the new isolates as representing a novel species in a new genus, for which the name Sediminimonas qiaohouensis gen. nov., sp. nov. is proposed. The type strain of the type species is YIM B024(T) (=KCTC 22349(T)=CCTCC AA 208033(T)).

Salipiger mucescens gen. nov., sp. nov., a moderately halophilic, exopolysaccharide-producing bacterium isolated from hypersaline soil, belonging to the alpha-Proteobacteria.

Salipiger mucescens gen. nov., sp. nov. is a moderately halophilic, exopolysaccharide-producing, Gram-negative rod isolated from a hypersaline habitat in Murcia in south-eastern Spain. The bacterium is chemoheterotrophic and strictly aerobic (i.e. unable to grow under anaerobic conditions either by fermentation or by nitrate or fumarate respiration). It does not synthesize bacteriochlorophyll a. Catalase and phosphatase are positive. It does not produce acids from carbohydrates. It cannot grow with carbohydrates or amino acids as sole sources of carbon and energy. It grows best at 9-10 % w/v NaCl and requires the presence of Na+ but not Mg2+ or K+, although they do stimulate its growth somewhat when present. Its major fatty-acid component is 18 : 1omega7c (78.0 %). The predominant respiratory lipoquinone found in strain A3T is ubiquinone with ten isoprene units. The G + C content is 64.5 mol%. Phylogenetic analyses strongly indicate that this strain forms a distinct line within a clade containing the genus Roseivivax in the subclass alpha-Proteobacteria. The similarity value with Roseivivax halodurans and Roseivivax halotolerans is 94 %. In the light of the polyphasic evidence gathered in this study it is proposed that the isolate be classified as representing a new genus and species, Salipiger mucescens gen. nov., sp. nov. The proposed type strain is strain A3T (= CECT 5855T = LMG 22090T = DSM 16094T).