Pelagibacterium halotolerans gen. nov., sp. nov. and Pelagibacterium luteolum sp. nov., novel members of the family Hyphomicrobiaceae

Abstract

Two Gram-negative, motile, aerobic bacterial strains, designated B2T and 1_C16_27T, were respectively isolated from a seawater sample collected from the East China Sea and a semi-coke sample from north-eastern Estonia. Their genetic, phenotypic and chemotaxonomic properties were studied. The isolates were short rods with polar flagella and were positive for catalase and oxidase activities. Q-10 was the predominant respiratory ubiquinone. The major polar lipids were phosphatidylglycerol, diphosphatidylglycerol and two unidentified glycolipids. The major fatty acids were nonadecanoic (C19 : 0 cyclo), octadecanoic (C18 : 0 and C18 : 0 3-OH), octadecenoic (C18 : 1) and hexadecanoic (C16 : 0) acids. The G+C content of the genomic DNA was 58.1–59.3 mol%. 16S rRNA gene sequence analysis revealed that the two isolates represent a distinct lineage within the family Hyphomicrobiaceae. The phylogenetically closest relatives were Cucumibacter (92.7–93.7 % 16S rRNA gene sequence similarity), Devosia (92.9–94.4 %) and Zhangella (91.7–92.1 %). Differential phenotypic properties, together with phylogenetic and genetic distinctiveness, revealed that strains B2T and 1_C16_27T could be differentiated from each other and from members of the genera Cucumibacter, Devosia and Zhangella. Therefore, it is proposed that strains B2T and 1_C16_27T represent two novel species in a new genus, for which the names Pelagibacterium halotolerans gen. nov., sp. nov. (the type species; type strain B2T = CGMCC 1.7692T = JCM 15775T) and Pelagibacterium luteolum sp. nov. (type strain 1_C16_27T = CGMCC 1.10267T = JCM 16552T = CELMS EEUT 1C1627T) are proposed.

Cloning, expression and characterization of a halotolerant esterase from a marine bacterium Pelagibacterium halotolerans B2T

“…But unlike most halophlic enzymes of halophilic archaea which are inactive under low salt concentrations (Cao et al 2008), PE10 was still active without NaCl. Pelagibacterium halotolerans B2 T was isolated from sea water and can grow under 0-13 % (0-2.22 M) NaCl (Xu et al 2011), so it is reasonable that its enzymes were halotolerance. Halophilic archaea establish an osmotic balance with their high salt environment by maintaining internal levels of salt that are isotonic with the exterior (Kushner 1988).…”

“…Pelagibacterium halotolerans B2 T , a novel member of the family Hyphomicrobiaceae, was isolated from East China Sea (125°59 0 24 00 E, 30°58 0 16 00 N) from a depth of 70 m (Xu et al 2011), and it was cultivated in marine 2216 broth (BD, USA) at 30°C. E. coli DH5a and E. coli Rosetta (DE3) (Novagen, Germany) used for plasmid manipulation and protein expression were grown in LB medium containing 10 g NaCl, 10 g tryptone and 5 g yeast extract per one liter at pH 7.0, and LB solid medium was supplemented with 1.5 % (w/v) agar.…”

“…We isolated a novel member of the family Hyphomicrobiaceae from East China Sea. This strain, Pelagibacterium halotolerans B2 T , exhibited esterase activity (Xu et al 2011) and so it was chosen for further study of esterase.…”

Paracoccus sediminis sp. nov., isolated from Pacific Ocean marine sediment

“…T was isolated from a marine sediment sample collected from the East China Sea (125 u 599 240 E 30 u 589 160 N) at a depth of 70 m (Xu et al, 2011). The sediment was diluted with sterile seawater and spread on modified marine agar 2216 containing the same ingredients as marine agar 2216 (MA; Difco), except that peptone and yeast were reduced to 0.1 g l 21 and 0.5 g l 21 , respectively.…”

Complete Genome Sequence of Pelagibacterium halotolerans B2T

“…), but only a few have been isolated from marine environments. Cucumibacter marinus (6), Filomicrobium fusiforme (11), Hyphomicrobium aestuarii (4), Pelagibacterium halotolerans (14), and Zhangella mobilis (13) have been isolated from marine environments. Strain B2 T , isolated from a seawater sample from a depth of 70 m in the East China Sea, is the type strain of Pelagibacterium halotolerans, which in turn is the type species of the genus Pelagibacterium in the family Hyphomicrobiaceae (14).…”