Halovulum dunhuangense gen. nov., sp. nov., isolated from a saline terrestrial spring

Abstract

A bacterial strain, T , isolated from a mixed water-sand-sediment sample collected from a terrestrial spring located in Dunhuang, China, was characterized with respect to its morphology, physiology and taxonomy. Cells of the strain were Gram-stain-negative, aerobic, oxidase-and catalase-positive, non-flagellated, oval to rod-shaped (0.5-1.0 mm wide and 1.1-6.6 mm long) and divided by binary fission. Growth was observed in the presence of 0-10.0 % (w/v) NaCl with optimal growth at 0-3.0 %, at pH 6.0-9.0 (optimum pH 7.0-8.5) and at 10-45 8C (optimum 30-37 8C). The isolate could reduce nitrate to nitrite and hydrolyse aesculin and gelatin (weakly), but was unable to degrade Tween 80 or starch. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain YYQ-30 T belongs to the family Rhodobacteraceae and forms a distinct lineage with the type strain of Albimonas donghaensis and forms a branch within a cluster constituted by the type strains of species of the genera Albimonas, Rhodovulum, Albidovulum, Haematobacter and Tropicimonas; levels of 16S rRNA gene sequence similarity between strain YYQ-30 T and members of related genera ranged from 94.1 to 89.7 %. Strain YYQ-30 T contained Q-10 as the predominant ubiquinone and summed feature 8 (C 18 : 1 v7c and/or C 18 : 1 v6c; 70.0 %), C 18 : 0 (9.5 %), summed feature 2 (one or more of C 14 : 0 3-OH, iso-C 16 : 1 I and C 12 : 0 aldehyde; 6.9 %) and 11-methyl C 18 : 1 v7c (6.0 %) as the principal fatty acids. The polar lipids comprised diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, three unidentified phospholipids, two unidentified aminolipids and five unknown lipids. The pufLM gene was detected. The G+C content of the genomic DNA was 71.7 mol%. Based on the phylogenetic, chemotaxonomic and phenotypic data obtained in this study, strain YYQ-30 T is considered to represent a novel species in a new genus within the family Rhodobacteraceae, for which the name Halovulum dunhuangense gen. nov., sp. nov. is proposed. The type strain of Halovulum dunhuangense is YYQ-30During an investigation of bacterial diversity of a terrestrial spring, strain YYQ-30 T was isolated and characterized taxonomically along with several other bacterial isolates. Comparative 16S rRNA gene sequence analysis indicated that strain YYQ-30 T belongs to the family Rhodobacteraceae. However, it could not be assigned to any genus because of its low sequence similarity to any type strain (,94.1 %). The type genus of the family Rhodobacteraceae, Rhodobacter, was proposed by Imhoff et al. (1984) and, at the time of writing, the family comprised 105 genera (http://www.bacterio.net/rhodobacteraceae.html). Consequently, the aim of the present work was to determine the exact taxonomic position of strain T by using a polyphasic approach.A mixed water-sand-sediment sample was collected from a terrestrial spring named Crescent Moon Spring located at the foot of Echoing-Sand Mountain in the desert of Dunhuang County, Gansu Province, China (40.58 N 94.408 E) and used for bacter...

Halovulum marinum sp. nov., isolated from deep-sea water of the Indian Ocean, and emended description of the genus Halovulum

“…At the time of its first nomination, the Amaricoccus group contained five genera with diverse metabolic lifestyles, including chemoorganoheterotrophs ( Amaricoccus [7], Albimonas [8] and Oceanicella [9]), aerobic anoxygenic photoheterotrophs ( Rubrimonas [10]) and purple non-sulfur photosynthetic bacteria ( Rubribacterium [11]). The genus Halovulum , a recently recognized member of the family Rhodobacteraceae , comprised only a single species (http://www.bacterio.net/index.html), Halovulum dunhuangense , was isolated from a mixed water-sand-sediment sample from a saline terrestrial spring [12]. In a survey of microbial diversity in the Northwest Indian Ocean, a novel strain, designated 2CG4 T was isolated.…”

“…On the basis of the results of phylogenetic characterization using the sequences of 16S rRNA genes and RpoC proteins, 2CG4 T was proposed to be the type strain of a novel species of the genus Halovulum , which fell in the Amaricoccus clade of the family Rhodobacteraceae. H. dunhuangense YYQ-30 T [12], the most closely related phylogenetic neighbor to 2CG4 T , was obtained from the Marine Culture Collection of China (MCCC) and used as a reference strain for comparative purposes. For long-term storage, 2CG4 T and H.…”

“… *Different result (shown in parentheses) reported by Sun et al ., 2015 [12]. †Summed feature eight comprises C 18 : 1 ω7 c and/or C 18 : 1 ω6 c. …”

“…In comparison, H. dunhuangense YYQ-30 T contained summed feature 8 and 11-methyl C 18 : 1 ω7 c , a methylated unsaturated fatty acid [12]. The detailed fatty acid data are listed in .…”

“…This value was slightly lower than that of H. dunhuangense YYQ-30 T (71.7 %) [12]. The genetic potential for anoxygenic phototrophy was examined by searching the central genes in the photosynthetic reaction ( pufLM ) in the whole genome of 2CG4 T , and by PCR amplification of the genes using the primers pufLf (5′-CTKTTCGACTTCTGGGTSGG-3′) and pufMr (5′-CCCATSGTCCAGCGCCAGAA-3′) [26].…”