Devosia aquimaris sp. nov., isolated from seawater of the Changjiang River estuary of China.

A gram-stain-negative, aerobic, rod-shaped bacterium strain CJK-A8-3T was isolated from a polyamine-enriched seawater sample collected from the Changjiang River estuary of China. The colonies were white and circular. Strain CJK-A8-3T grew optimally at 35 °C, pH 7.0 and 1.5% NaCl. Its polar lipids contained phosphatidylglycerol, phosphatidic acid, unidentified glycolipids, and a combination of phospholipids and glycolipids. The respiratory quinone was ubiquinone-10, and its main fatty acids were C16:0, 11-methyl C18:1ω7c and Summed Feature 8 (including C18:1ω7c/C18:1ω6c). The phylogenetic tree based on 16S rRNA genes placed strain CJK-A8-3T in a new linage within the genus Devosia. 16S rRNA gene sequence of strain CJK-A8-3T showed identities of 98.50% with Devosia beringensis S02T, 98.15% with D. oryziradicis, and 98.01% with D. submarina JCM 18935T. The genome size of strain CJK-A8-3T was 3.81 Mb with the DNA G + C content 63.9%, higher than those of the reference strains (60.4-63.8%). The genome contained genes functional in the metabolism of terrigenous aromatic compounds, alkylphosphonate and organic nitrogen, potentially beneficial for nutrient acquirement and environmental remediation. It also harbored genes functional in antibiotics resistance and balance of osmotic pressure, enhancing their adaptation to estuarine environments. Both genomic investigation and experimental verification showed that strain CJK-A8-3T could be versatile and efficient to use diverse organic nitrogen compounds as carbon and nitrogen sources. Based on phenotypic, chemotaxonomic, phylogenetic and genomic characteristics, strain CJK-A8-3T was identified as a novel Devosia species, named as Devosia aquimaris sp. nov. The type strain is CJK-A8-3T (= MCCC 1K06953T = KCTC 92162T).

Biodegradation of low-density polyethylene film by two bacteria isolated from plastic debris in coastal beach.

Low-density polyethylene (LDPE) conduces massive environmental accumulation due to its high production and recalcitrance to environment. In this study, We successfully enriched and isolated two strains, Nitratireductor sp. Z-1 and Gordonia sp. Z-2, from coastal plastic debris capable of degrading LDPE film. After a 30-day incubation at 30 ℃, strains Z-1 and Z-2 decreased the weight of branched-LDPE (BLDPE) film by 2.59 % and 10.27 % respectively. Furthermore, high temperature gel permeation chromatography (HT-GPC) analysis revealed molecular weight reductions of 7.69 % (Z-1) and 23.22 % (Z-2) in the BLDPE film. Scanning electron microscope (SEM) image showed the presence of microbial colonization and perforations on the film's surface. Fourier transform infrared spectroscopy (FTIR) analysis indicated novel functional groups, such as carbonyl and carbon-carbon double bonds in LDPE films. During LDPE degradation, both strains produced extracellular reactive oxygen species (ROS). GC-MS analysis revealed the degradation products included short-chain alkanes, alkanols, fatty acids, and esters. Genomic analysis identified numerous extracellular enzymes potentially involved in LDPE chain scission. A model was proposed suggesting a coordinated role between ROS and extracellular enzymes in the biodegradation of LDPE. This indicates strains Z-1 and Z-2 can degrade LDPE, providing a basis for deeper exploration of biodegradation mechanisms.

Microbulbifer zhoushanensis sp. nov., Microbulbifer sediminum sp. nov. and Microbulbifer guangxiensis sp. nov., three marine bacteria isolated from a tidal flat.

Three strains, TT30T, TT37T and L3T, were isolated from tidal flat samples. Cells were Gram-stain-negative, non-motile and rod shaped. Cells of strains TT30T and TT37T were able to grow in a medium containing 1.0-15.0 % (w/v) NaCl (optimum, 3.0 and 4.0 %, respectively), and cells of strain L3T was able to grow in a medium containing 1.0-10.0 % (w/v) NaCl (optimum, 1.0 %). Growth of the three strains was observed at pH 6.0-10.0 and at 10-40 °C. Strains TT30T, TT37T and L3T showed the highest similarity to Microbulbifer hydrolyticus DSM 11525T (97.7 %), M. yueqingensis CGMCC 1.10658T (98.0 %) and M. elongatus DSM 6810T (97.9 %), respectively. Results of phylogenetic analyses indicated that the three isolates represented two distinct lineages within the genus Microbulbifer. The DNA G+C contents of strains TT30T, TT37T and L3T were 61.3, 60.9 and 60.2%, respectively. The average nucleotide identity and in silico DNA-DNA hybridization values among strains TT30T, TT37T and L3T and the reference strains were 84.4-87.4 and 19.6-28.9 %, respectively. Differential phenotypic properties, chemotaxonomic differences, phylogenetic distinctiveness, together with the genomic data, demonstrated that strains TT30T, TT37 T and L3T represent novel species of the genus Microbulbifer, which are named Microbulbifer zhoushanensis sp. nov. (TT30T=KCTC 92167T=MCCC 1K07276T), Microbulbifer sediminum sp. nov. (TT37T=KCTC 92168T=MCCC 1K07277T) and Microbulbifer guangxiensis sp. nov. (L3T=KCTC 92165T=MCCC 1K07278T).

Rheinheimera oceanensis sp. nov., a novel member of the genus Rheinheimera, isolated from the West Pacific Ocean.

Two Gram-stain-negative, aerobic, non-motile and short-rod-shaped bacteria, designated as strains GL-53T and GL-15-2-5, were isolated from the seamount area of the West Pacific Ocean and identified using a polyphasic taxonomic approach. The growth of strains GL-53ᵀ and GL-15-2-5 occurred at pH 5.5-10.0, 4-40 °C (optimum at 28 °C) and 0-10.0 % NaCl concentrations (optimum at 0-5.0 %). On the basis of 16S rRNA gene sequence analysis, strains GL-53ᵀ and GL-15-2-5 exhibited the highest similarity to Rheinheimera lutimaris YQF-2T (98.4 %), followed by Rheinheimera pacifica KMM 1406T (98.1 %), Rheinheimera nanhaiensis E407-8T (97.4 %), Rheinheimera aestuarii H29T (97.4 %), Rheinheimera hassiensis E48T (97.2 %) and Rheinheimera aquimaris SW-353T (97.2 %). Phylogenetic analysis revealed that the isolates were affiliated with the genus Rheinheimera and represented an independent lineage. The major fatty acids were summed feature 3 (C16 : 1 ω7c and/or C16 : 1 ω6c), C16 : 0 and summed feature 8 (C18 : 1 ω7c and/or C18 : 1 ω6c). The sole isoprenoid quinone was ubiquinone 8. The major polar lipids were phosphatidylethanolamine, phosphatidylglycerol, one unidentified aminophospholipid (and one unidentified glycolipid. The DNA G+C content was 48.5 mol%. The average nucleotide identity, average amino acid identity and in silico DNA-DNA hybridization values among the genomes of strain GL-53ᵀ and the related strains in the genus Rheinheimera were 75.5-90.1 %, 67.5-93.9 % and 21.4-41.4 %, respectively. Based on their phenotypic, chemotaxonomic and genotypic properties, the two strains were identified as representing a novel species of the genus Rheinheimera, for which the name Rheinheimera oceanensis sp. nov. is proposed. The type strain is GL-53T (=KCTC 82651T=MCCC M20598T).

Mesobacterium pallidum gen. nov., sp. nov., Heliomarina baculiformis gen. nov., sp. nov. and Oricola indica sp. nov., three novel Alphaproteobacteria members isolated from deep-sea water in the southwest Indian ridge.

Three Gram-staining-negative, aerobic and rod-shaped strains, designated as T40-1T, T40-3T and JL-62T, were isolated from the deep-sea water in the southwest Indian ridge. For strain T40-1T, growth occurred at 15-37 °C (optimum, 28 °C), pH 6.0-9.0 (optimum, pH 7.5) and in the presence of 0.5-5.0 % NaCl (w/v; optimum, 2.0 %). Strain T40-3T could grow at 15-40 °C (optimum, 28 °C), with 0.5-11.0 % NaCl (optimum, 2.0 %, w/v) at pH 6.0-9.5 (optimum, 8.0). The temperature, pH and salinity ranges for growth of strain JL-62T were 15-40 °C (optimum, 30 °C), pH 5.5-9.0 (optimum, pH 7.5-8.0) and 0.5-9.0 % NaCl (w/v; optimum, 4.0 %). Ubiquinone-10 was the sole ubiquinone in all strains, the major fatty acids (>20 %) were summed feature 8 (C18 : 1 ω7c / C18 : 1 ω6c). The major polar lipids of strains T40-1T and T40-3T were phosphatidylcholine, phosphatidylglycerol, phosphatidylethanolamine and diphosphatidylglycerol. Strain JL-62T contained phosphatidylmonomethylethanolamine, diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol and sulfoquinovosyldiacylglycerol as major polar lipids. Phylogenetic trees based on 16S rRNA gene and core-genomic sequences revealed affiliation of strains T40-1Tand T40-3T to the family Roseobacteraceae and formed two independent clades from other Roseobacteraceae genera, and those two strains had average nucleotide identities of 62.0-72.0 % to their phylogenetically related species which fell into to the genus boundary range, indicating that they represent two novel genera. While strain JL-62T represents a novel species in the genus Oricola belonging to the family Phyllobacteriaceae, which was supported by overall genomic relatedness index calculations. The DNA G+C contents of strains T40-1T, T40-3T and JL-62T were 66.5, 60.1 and 62.1 mol %, respectively. Based on the polyphasic taxonomic data, strains T40-1T (=MCCC M24557T=KCTC 82975T) and T40-3T (=MCCC 1K05135T=KCTC 82976T) are classified as representing two novel genera belonging to the family Roseobacteraceae with the names Mesobacterium pallidum gen. nov., sp. nov. and Heliomarina baculiformis gen. nov., sp. nov. are proposed, and strain JL-62T (=MCCC M24579T=KCTC 82974T) is proposed to represent a novel species within the genus Oricola with the name Oricola indica sp. nov. is proposed.

Luteirhabdus pelagi gen. nov., sp. nov., a novel member of the family Flavobacteriaceae, isolated from the West Pacific Ocean.

A Gram-stain-negative, aerobic, and yellow-pigmented bacterium, designated A3-108T, was isolated from seawater of the West Pacific Ocean. Cells were non-motile and rod-shaped, with carotenoid-type pigments. Strain A3-108T grew at pH 6.0-8.5 (optimum 6.5) and 15-40 °C (optimum 28 °C), in the presence of 0.5-10% (w/v) NaCl (optimum 1.0%). It possessed the ability to produce H2S. Based on the 16S rRNA gene analysis, strain A3-108T exhibited highest similarity with Aureisphaera salina A6D-50T (90.6%). Phylogenetic analysis shown that strain A3-108T affiliated with members of the family Flavobacteriaceae and represented an independent lineage. The principal fatty acids were iso-C15:0, iso-C17:0 3-OH, iso-C15:1 G, and summed feature 3 (C16:1ω7c and/or C16:1ω6c). The sole isoprenoid quinone was MK-6. The major polar lipids were phosphatidylethanolamine, one unidentified aminophospholipid, one unidentified aminolipid and one unidentified lipid. The ANIb, in silico DDH and AAI values among the genomes of strain A3-108T and three reference strains were 67.3-71.1%, 18.7-22.1%, and 58.8-71.4%, respectively. The G + C content was 41.0%. Distinctness of the phylogenetic position as well as differentiating chemotaxonomic and other phenotypic traits revealed that strain A3-108T represented a novel genus and species of the family Flavobacteriaceae, for which the name Luteirhabdus pelagi gen. nov., sp. nov. is proposed (type strain, A3-108T = CGMCC 1.18821T = KCTC 82563T).

Physiological and genomic features of Henriciella with the description of Henriciella mobilis sp. nov.

Strains M65T, M69 and JN25 were isolated from seawater of the West Pacific Ocean. Cells of the three strains were Gram-stain-negative, aerobic and rod-shaped. Cells were motile by means of flagella. On the basis of the results of 16S rRNA gene sequence analysis, strains M65T, M69 and JN25 showed the highest 16S rRNA gene sequence similarity to Henriciella algicola MCS27T (98.8 %), followed by Henriciella marina DSM 19595T (98.4 %), Henriciella barbarensis MCS23T (98.4 %), Henriciella pelagia LA220T (98.3 %), Henriciella aquimarina P38T (98.1 %) and Henriciella litoralis SD10T (97.8 %). The 16S rRNA gene sequence similarities among the isolates were 100 %. Phylogenetic analyses revealed that the isolates fell within a cluster comprising the Henriciella species and represented an independent lineage. The average nucleotide identity and in silico DNA-DNA hybridization values between strain M65T and the type strains of Henriciella species were 73.9-85.8 % and 19.9-22.4 %, respectively. The sole respiratory quinone detected in the three isolates was ubiquinone 10. The principal fatty acids were summed feature 8 (C18 : 1 ω7c and/or C18 : 1 ω6c) and C16 : 0. The major polar lipids were glucuronopyranosyldiglyceride, monoglycosyldiglyceride and one unidentified glycolipid. The DNA G+C content was 61.3-61.4 mol%. Phylogenetic distinctiveness, chemotaxonomic differences, together with phenotypic properties, revealed that the isolates could be differentiated from the Henriciella species with validly published names. Therefore, it is proposed that strains M65T, M69 and JN25 represent a novel species of the genus Henriciella, for which the name Henriciella mobilis sp. nov. (type strain, M65T=CGMCC 1.15927T=KCTC 52576T) is proposed.

Alterinioella nitratireducens gen. nov., sp. nov., Isolated from Seawater in the West Pacific Ocean.

A novel Gram-negative, nonspore forming, nonmotile, and short-rod-shaped aerobic bacterium, designated DY48A3-103T, was isolated from a seawater sample collected from the West Pacific Ocean. Strain DY48A3-103T showed oxidase-positive and catalase-positive activities. Growth was observed at 10-37 °C (optimum 30 °C), at pH 6.5-9.5 (optimum 8.0) and in 1-11% NaCl (optimum 3%, w/v). 16S rRNA gene sequence analysis exhibited 96.3%, 96.1%, 96.0%, and 94.9% sequence similarity to the type strains Rhodophyticola porphyridii MA-7-27T, Nioella sediminis JS7-11T, N. nitratireducens SSW136T, and Jannaschia helgolandensis DSM 14858T, respectively. Strain DY48A3-103T and the type strains of phylogenetically related species have 61.7-75.4% AAI values, which fell into to the genus boundary range (60-80% AAI). Phylogenetic trees based on the 16S rRNA gene sequences and the genome sequences of strain DY48A3-103T revealed that it was affiliated to the members of the family Rhodobacteraceae. The G+C content was 65.4%. The sole isoprenoid quinone was Q-10. The predominant polar lipids were phosphatidylcholine and phosphatidylglycerol. Major fatty acids were summed feature 8 (comprising C18:1ω7c and/or C18:1ω6c), C19:0 cyclo ω8c, and C16:0. On the basis of the phenotypic, chemotaxonomic, and genomic properties, strain DY48A3-103t is proposed to represent a novel genus and a novel species, Alterinioella nitratireducens gen. nov., sp. nov., in the family Rhodobacteraceae. The type strain is DY48A3-103T (= KCTC 72738T = MCCC 1K04322T).

Muricauda maritima sp. nov., Muricauda aequoris sp. nov. and Muricauda oceanensis sp. nov., three marine bacteria isolated from seawater.

Three Gram-stain-negative, non-motile, rod-shaped strains, designated 72T, NH166T and 40DY170T, were isolated from seawater samples of the West Pacific Ocean, South China Sea and West Pacific Ocean, respectively. The 16S rRNA gene sequence similarity results revealed that strains 72Tand NH166T were most closely related to Muricauda antarctica Ar-22T, Muricauda taeanensis JCM 17757T, Muricauda beolgyonensis KCTC 23501T, Muricauda lutimaris KCTC 22173T and Muricauda hadalis MT-229T with 97.2-98.0% sequence similarity. 16S rRNA gene sequence analysis also indicated that strain 40DY170T was most closely related to Muricauda ruestringensis DSM 13258T, Muricauda aquimarina JCM 11811T, Muricauda lutimaris KCTC 22173T and Muricauda oceani 501str8T with 97.6-98.1% sequence similarity. The 16S rRNA gene sequence similarity values among strains 72T, NH166T and 40DY170T were 96.5-99.2%. Phylogenetic analyses indicated that three new isolates represented three novel species by forming two distinctive lineages within the genus Muricauda. The DNA G+C contents of strain 72T, NH166T and 40DY170T were 43.4, 43.4 and 42.4 mol%, respectively. The average nucleotide identity and in silico DNA-DNA hybridization values between strains 72T, NH166T, 40DY170T and the reference strains were 76.5-93.5% and 19.2-53.5%, respectively. The sole respiratory quinone in all strains was menaquinone-6. Their major fatty acids were iso-C17:0 3-OH, iso-C15:0 and iso-C15 : 1 G. The major polar lipids of strains 72T and NH166T were phosphatidylethanolamine, one unidentified aminolipid and two unidentified lipids. The major polar lipids of strain 40DY170T were phosphatidylglycerol, one unidentified phospholipid, one unidentified aminolipid and two unidentified lipids. On the basis of their distinct taxonomic characteristics, the three isolates represent three novel species of the genus Muricauda, for which the names Muricauda maritima sp. nov. (type strain 72T=KCTC 62229T=MCCC 1K03350T), Muricauda aequoris sp. nov. (NH166T=KCTC 62228T=MCCC 1K03449T) and Muricauda oceanensis sp. nov. (40DY170T=KCTC 72200T=MCCC 1K03569T) are proposed.

Discovery and mechanism of intestinal bacteria in enzymatic cleavage of C-C glycosidic bonds.

C-Glycosides, a special type of glycoside, are frequently distributed in many kinds of medicinal plants, such as puerarin and mangiferin, showing various and significant bioactivities. C-Glycosides are usually characterized by the C-C bond that forms between the anomeric carbon of sugar moieties and the carbon atom of aglycon, which is usually resistant against acidic hydrolysis and enzymatic treatments. Interestingly, C-glycosides could be cleaved by several intestinal bacteria, but whether the enzymatic cleavage of C-C glycosidic bond is reduction or hydrolysis has been controversial; furthermore, whether existence of a "C-glycosidase" directly catalyzing the cleavage is not clear. Here we review research advances about the discovery and mechanism of intestinal bacteria in enzymatic cleavage of C-C glycosidic bond with an emphasis on the identification of enzymes manipulation the deglycosylation. Finally, we give a brief conclusion about the mechanism of C-glycoside deglycosylation and perspectives for future study in this field.

Tsuneonella suprasediminis sp. nov., isolated from the Pacific Ocean.

A Gram-stain-negative, rod-shaped and aerobic bacterial strain, named Ery12T, was isolated from the overlying water of the Lau Basin in the Southwest Pacific Ocean. Strain Ery12T showed high 16S rRNA gene sequences similarity to Tsuneonella flava MS1-4T (99.9 %), T. mangrovi MCCC 1K03311T (98.1 %), Altererythrobacter ishigakiensis NBRC 107699T (97.3 %) and exhibited ≤97.0 % sequence similarity with other type strains of species with validly published names. Growth was observed in media with 0-10.0 % NaCl (optimum 0-1.0 %, w/v), pH 5.0-9.5 (optimum 6.0-7.0) and 10-42 °C (optimum 30-37 °C). The predominant respiratory quinone was ubiquinone 10 (Q-10). The major cellular fatty acid was summed feature 8 (C18 : 1 ω7c and/or C18 : 1 ω6c). The major polar lipids were sphingoglycolipid, phosphatidyglycerol, diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine, three unidentified glycolipids, one unidentified aminoglycolipid and one unidentified lipid. The DNA G+C content was 60.8 %. The ANI and in silico DDH values between strain Ery12T and the type strains of its closely related species were 71.0- 91.8 % and 19.5- 44.6 %, respectively. According to the phenotypic, chemotaxonomic, phylogenetic and genomic data, strain Ery12T represents a novel species of the genus Tsuneonella, for which the name Tsuneonella suprasediminis is proposed. The type strain is Ery12T (=CGMCC 1.16500 T=MCCC 1A04421T=KCTC 62388T). We further propose to reclassify Altererythrobacter rhizovicinus and Altererythrobacter spongiae as Pelagerythrobacter rhizovicinus comb. nov. and Altericroceibacterium spongiae comb. nov., respectively.

Alteromonas alba sp. nov., a marine bacterium isolated from seawater of the West Pacific Ocean.

A Gram-stain-negative, strictly aerobic, motile by one polar flagellum, non-spore-forming, rod-shaped bacterium, designated as 190T, was isolated from seawater of the West Pacific Ocean and subjected to a polyphasic taxonomic investigation. Colonies were 1.0-2.0 mm in diameter, smooth, circular, convex and white after growth on marine agar at 30 °C for 24 h. Strain 190T was found to grow at 4-40 °C (optimum, 30 °C), at pH 5.5-10.5 (optimum, pH 6.5) and with 0.5-12.5 % (w/v) NaCl (optimum, 2.0 %). Chemotaxonomic analysis showed the sole respiratory quinone was ubiquinone 8 (Q-8), and the major fatty acids were summed feature 3 (C16 : 1ω7c and/or iso-C15 : 0 2-OH), C16 : 0 and summed feature 8 (C18 : 1ω6c and/or C18 : 1ω7c). The major polar lipids were phosphatidylethanolamine (PE), phosphatidylglycerol (PG), one unidentified aminolipid (AL1) and two unidentified glycolipids (GL1, GL2). The DNA G+C content of strain 190T was 48.7 mol% based on the genome sequence. The comparison of 16S rRNA gene sequence similarities showed that strain 190T was closely related to Alteromonas oceani S35T (99.6 % sequence similarity), A. lipolytica JW12T (98.2 %), A. aestuariivivens JDTF-113T (97.7 %) and A. mediterranea DET (97.5 %); it exhibited 97.0 % or less sequence similarity with the type strains of other species with validly published names. Phylogenetic trees reconstructed with the neighbour-joining, maximum-parsimony and maximum-likelihood methods based on 16S rRNA gene sequences showed that strain 190T constituted a separate branch with A. oceani, A. confluentis, A. aestuariivivens and A. lipolytica in a clade of the genus Alteromonas. OrthoANI values between strain 190T and A. oceani S35T and A. lipolytica JW12T were 93.5 and 77.9 %, respectively, and in silico DNA-DNA hybridization values were 53.8 and 21.2 %, respectively. Differential phenotypic properties, together with phylogenetic distinctiveness, demonstrated that strain 190T is clearly distinct from recognized species of the genus Alteromonas. On the basis of these features, we propose that strain 190T (=MCCC 1K03456T=KCTC 62227T) represents a novel species of the genus Alteromonas with the name Alteromonas alba sp. nov.

Erythrobacter zhengii sp. nov., a bacterium isolated from deep-sea sediment.

A Gram-stain-negative, strictly aerobic, rod-shaped bacterium, designated V18T, was isolated from a deep-sea sediment sample collected from the Pacific Ocean and subjected to a polyphasic taxonomic investigation. Cells of strain V18T grew in medium containing 0-10.0 % (w/v) NaCl (optimum 1.0 %), at pH 5.5-9.0 (optimum 6.5-7.0) and at 10-40 °C (optimum 30-37 °C). Aesculin and Tweens 20, 40, 60 and 80 were hydrolysed. The isolate contained carotenoid-like pigments and lacked bacteriochlorophyll a. Strain V18T was closely related to members of the genus Erythrobacter, namely Erythrobacter odishensis JA747T (98.9 % 16S rRNA gene sequence similarity), E. westpacificensis JLT2008T (98.8 %), E. gangjinensis K7-2T (97.7 %), E. aquimixticola JSSK-14T (97.6 %), E. marinus KCTC 23554T (97.4 %), E. atlanticus s21-N3T (97.3 %), E. arachoides RC4-10-4T (97.2 %), E. citreus RE35F/1T (97.1 %) and E. luteus KA37T (97.0 %), and exhibited less than 97.0 % sequence similarity with the type strains of other species with validly published names. Phylogenetic analyses revealed that strain V18T clustered with E. odishensis JA747T and formed an independent lineage. The average nucleotide identity and in silico DNA-DNA hybridization values between strain V18T and the type strains of Erythrobacter species were 70.5-83.4 % and 18.4-26.1 %, respectively. Strain V18T contained ubiquinone 10 (Q-10) as the sole respiratory quinone. The major fatty acids (>10 %) were summed feature 8 (C18 : 1ω7c and/or C18 : 1ω6c), summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c) and C16 : 0. The major polar lipids were sphingoglycolipid (SGL), diphosphatidylglycerol (DPG), phosphatidyglycerol (PG), phosphatidylethanolamine (PE) and one unidentified lipid (L1). The DNA G+C content was 62.6 mol%. According to the phenotypic, chemotaxonomic and phylogenetic data, strain V18T represents a novel species of the genus Erythrobacter, for which the name Erythrobacter zhengii is proposed. The type strain is V18T (=KCTC 62389T=MCCC 1K03475T).

Altererythrobacter aerophilus sp. nov., isolated from deep-sea water of the north-west Pacific.

A Gram-stain-negative, rod-shaped bacterium, designated Ery1T, was isolated from deep-sea seawater collected from the Mariana Trench and subjected to a polyphasic investigation for taxonomy. Strain Ery1T was able to grow in medium containing 0-10 % NaCl (w/v; optimum, 0-1.0 %), pH 5.0-9.5 (optimum, pH 6.0-7.0) and at temperatures between 10-45 °C (optimum, 30-40 °C). The comparison of 16S rRNA gene sequences revealed that strain Ery1T showed highest similarity to Altererythrobacterxinjiangensis S3-63T (97.7 %) and Altererythrobacterrigui WW3T (97.6 %), and exhibited less than 97.5 % sequence similarity to other type strains of the species with validly published names. Phylogenetic analyses indicated that strain Ery1T fell within the cluster comprising the Altererythrobacter species and formed a coherent clade with Altererythrobacterxinjiangensis and Altererythrobactersoli. The OrthoANIu and in silico DNA-DNA hybridization values between strain Ery1T and the reference strains were 73.8-75.9 % and 19.2-20.1 %, respectively. Strain Ery1T contained Q-10 as the major respiratory quinone and Q-11 in a minor amount. The major fatty acids (>10 %) were summed feature 8 (C18 : 1ω7c and/or C18 : 1ω6c), summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c), C16 : 0, C18 : 1ω7c 11-methyl and C14 : 0 2-OH. The major polar lipids were sphingoglycolipid, diphosphatidylglycerol, phosphatidyglycerol, phatidylethanolamine, phosphatidylcholine and three unidentified glycolipids. Differential phenotypic properties, chemotaxonomic differences, phylogenetic distinctiveness, together with the genomic data demonstrated that strain Ery1T represents a novel species of the genus Altererythrobacter, for which named as Altererythrobacter aerophilus sp. nov. with the type strain Ery1T (=KCTC 62387T=CGMCC 1.16499T=MCCC 1A10037T).

Complete Genome Sequence of Qipengyuania sediminis CGMCC 1.12928T, Shed Light on Its Role in Matter-Cycle and Cold Adaption Mechanism of the Genus Qipengyuania.

Qipengyuania sediminis CGMCC 1.12928T, a family member of Erythrobacteraceae, the class of Alphaproteobacteria, was isolated from a borehole sediment sample collected from Qiangtang Basin in Qinghai-Tibetan Plateau, the largest permafrost in China. Understanding bacterial molecular feature may shed light on the ecological strategy in the extreme environment. Here we describe the complete genome sequence and annotation of strain CGMCC 1.12928T, including the complete genome sequence and annotation. The genome of strain CGMCC 1.12928T consist of a single-circular chromosome, comprises 2,416,000 bp with an average G + C content of 66.7 mol%, and contains 2414 genes; including 2367 CDSs, 44 tRNA genes, as well as one operon of 16S-23S-5S rRNA genes. Genomic properties indicated that strain CGMCC 1.12928T has a relatively smaller genome size and higher G + C content within the family Erythrobacteraceae. In addition, genomic analysis revealed its genome contains multiple function genes responsible for nitrogen, sulfur and phosphorus cycles and explained the cold adaption mechanism. Thus, this strain plays an active role in the biogeochemical cycle in cold niche. The whole-genome of this isolate will widen our understanding of the ecological role of the genus Qipengyuania in permafrost.

Investigation of the thermophilic mechanism in the genus Porphyrobacter by comparative genomic analysis.

BACKGROUND: Type strains of the genus Porphyrobacter belonging to the family Erythrobacteraceae and the class Alphaproteobacteria have been isolated from various environments, such as swimming pools, lake water and hot springs. P. cryptus DSM 12079T and P. tepidarius DSM 10594T out of all Erythrobacteraceae type strains, are two type strains that have been isolated from geothermal environments. Next-generation sequencing (NGS) technology offers a convenient approach for detecting situational types based on protein sequence differences between thermophiles and mesophiles; amino acid substitutions can lead to protein structural changes, improving the thermal stabilities of proteins. Comparative genomic studies have revealed that different thermal types exist in different taxa, and few studies have been focused on the class Alphaproteobacteria, especially the family Erythrobacteraceae. In this study, eight genomes of Porphyrobacter strains were compared to elucidate how Porphyrobacter thermophiles developed mechanisms to adapt to thermal environments. RESULTS: P. cryptus DSM 12079T grew optimally at 50 °C, which was higher than the optimal growth temperature of other Porphyrobacter type strains. Phylogenomic analysis of the genus Porphyrobacter revealed that P. cryptus DSM 12079T formed a distinct and independent clade. Comparative genomic studies uncovered that 1405 single-copy genes were shared by Porphyrobacter type strains. Alignments of single-copy proteins showed that various types of amino acid substitutions existed between P. cryptus DSM 12079T and the other Porphyrobacter strains. The primary substitution types were changes from glycine/serine to alanine. CONCLUSIONS: P. cryptus DSM 12079T was the sole thermophile within the genus Porphyrobacter. Phylogenomic analysis and amino acid frequencies indicated that amino acid substitutions might play an important role in the thermophily of P. cryptus DSM 12079T. Bioinformatic analysis revealed that major amino acid substitutional types, such as changes from glycine/serine to alanine, increase the frequency of α-helices in proteins, promoting protein thermostability in P. cryptus DSM 12079T. Hence, comparative genomic analysis broadens our understanding of thermophilic mechanisms in the genus Porphyrobacter and may provide a useful insight in the design of thermophilic enzymes for agricultural, industrial and medical applications.

Minwuia thermotolerans gen. nov., sp. nov., a marine bacterium forming a deep branch in the Alphaproteobacteria, and proposal of Minwuiaceae fam. nov. and Minwuiales ord. nov.

Two Gram-stain-negative, strictly aerobic, non-motile, non-spore-forming, rod-shaped bacteria, designated as SY3-15Tand SY3-13, were isolated from a seawater sample of the South China Sea. Colonies were 0.5-1.0 mm in diameter, smooth, circular, convex and translucent after growth on marine agar at 37 °C for 3 days. The strains were found to grow at 20-50 °C (optimum, 42 °C), pH 6.0-8.5 (optimum, pH 6.5-7.5) and with 0.5-6.0 % (w/v) NaCl (optimum, 1.5-2.0 %). Chemotaxonomic analysis showed the sole respiratory quinone to be ubiquinone-10, the major fatty acids (>10 %) were C16 : 0 3-OH, C19 : 0cyclo ω9c, C18 : 1 3-OH and summed feature 8 (C18 : 1ω7c and/or C18 : 1ω6c), and the polar lipids were phosphatidylglycerol, two unidentified aminolipids and three unidentified lipids. The DNA G+C content was 67.2-67.4 mol% calculated by genome. The 16S rRNA gene sequences of strains SY3-15T and SY3-13 were identical and related to the genus Lutibaculum with a similarity of 92.1 %. The 16S rRNA gene phylogenetic trees reconstructed with neighbour-joining, maximum-parsimony and minimum-evolution methods showed that the strains constituted a deep and separated branch from other families of Alphaproteobacteria, and the phylogenetic trees based on concatenated 163 protein sequences from genome sequences showed that the clade in which strains SY3-15T and SY3-13 located was separated from the clade of the other orders of Alphaproteobacteria, indicating it may represent a novel family of a novel order. Based on their phenotypic properties and their phylogenetic distinctiveness, we propose strains SY3-15T (=MCCC 1K03467T=KCTC 62335T) and SY3-13 (=MCCC 1K03466=KCTC 62329) to represent a novel species of a novel genus with the name Minwuia thermotolerans gen. nov., sp. nov., and we propose Minwuiaceae fam. nov. and Minwuiales ord. nov. with Minwuia as the type genus.

Marinobacter fuscus sp. nov., a marine bacterium of Gammaproteobacteria isolated from surface seawater.

A Gram-stain-negative bacterium, designated NH169-3T, was isolated from a surface seawater sample of the South China Sea and subjected to a taxonomic polyphasic investigation. Strain NH169-3T was strictly aerobic, non-motile, non-spore-forming and rod-shaped. The colony was 1.0-2.0 mm in diameter after the growth on marine agar at 30 °C for 72 h. The centre of the colony was smooth, circular, convex and brown with a transparent periphery. Strain NH169-3T was able to grow at temperatures between 4-40 °C (optimum, 37 °C), pH 5.5-9.0 (pH 7.5) and with 0-12.5 % (w/v) NaCl (3.0 %). Chemotaxonomic analysis showed that the sole respiratory quinone of strain NH169-3T was ubiquinone 9; major fatty acids were C16 : 0 and C18 : 1ω9c, and major polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol and one unidentified glycolipid. The DNA G+C content was 52.7 mol%. The comparison of 16S rRNA gene sequences showed that strain NH169-3T was closely related to Marinobacter shengliensis SL013A34A2T with a similarity of 98.0 %. Three phylogenetic trees reconstructed with neighbour-joining, maximum-parsimony and maximum-likelihood methods using 16S rRNA gene sequences showed that strain NH169-3T was grouped into a separated branch with M. shengliensis SL013A34A2T in a clade of the genus Marinobacter and closely related to Marinobacter halophilus JCM 30472T, Marinobacter vinifirmus DSM 17747T and Marinobacter hydrocarbonoclasticus DSM 8798T. Analyses of both phenotypic and phylogenetic properties have suggested that strain NH169-3T was distinctive from species with validly published names in genus Marinobacter. Thus, strain NH169-3T (=MCCC 1K03455T=KCTC 62226T) is proposed as a novel species in genus Marinobacter with the name Marinobacter fuscus sp. nov.

Pseudooceanicola lipolyticus sp. nov., a marine alphaproteobacterium, reclassification of Oceanicola flagellatus as Pseudooceanicola flagellatus comb. nov. and emended description of the genus Pseudooceanicola.

A Gram-stain-negative, rod-shaped bacterium, designated 157T, was isolated from seawater collected from the Philippine Sea. Cells of strain 157T grew in medium containing 0.5-10.0 % NaCl (w/v, optimum 3 %), at pH 6.0-8.5 (optimum 7.0) and at 15-40 °C (optimum 30 °C). Tweens 20, 40 and 80 as well as urea were hydrolysed. The 16S rRNA gene sequence of strain 157T had a high sequence similarity with respect to Pseudooceanicola marinus AZO-CT (97.2 %), and exhibited less than 97.0 % sequence similarity to other type strains of the species with validly published names. Phylogenetic analyses revealed that strain 157T fell within a cluster comprising the Pseudooceanicola species and formed a coherent clade with P. marinus AZO-CT and Pseudooceanicola antarcticus Ar-45T. Strain 157T exhibited average nucleotide identity values of 74.5 and 74.9 % to P. marinus LMG 23705T and P. antarcticus Ar-45T, respectively. In silico DNA-DNA hybridization analysis revealed that strain 157T shared 20.2 % DNA relatedness with P. marinus LMG 23705T and 20.6 % with P. antarcticus Ar-45T, respectively. The sole isoprenoid quinone was ubiquinone 10. The major fatty acids were summed feature 8 (C18 : 1ω7c and/or C18 : 1ω6c), C19 : 0 cyclo ω8c, C16 : 0 2-OH and C16 : 0. The major polar lipids were phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol, one unidentified aminolipid and one unidentified glycolipid. The DNA G+C content was 64.6 mol%. According to the phylogenetic, chemotaxonomic and phenotypic data, it represents a novel species of the genus Pseudooceanicola, for which the name Pseudooceanicolalipolyticus is proposed. The type strain is 157T (=KCTC 52654T=MCCC 1K03317T). In addition, the description of the genus Pseudooceanicola is emended and Oceanicola flagellatus is reclassified as Pseudooceanicola flagellatus comb. nov., with the type strain DY470T (=CGMCC 1.12664T=LMG 27871T) proposed.

Gracilimonas amylolytica sp. nov., isolated from deep-sea sediment.

A Gram-stain-negative, aerobic, non-motile and rod-shaped bacterium, designated LA399T, was isolated from deep-sea sediment collected from the Pacific Ocean. Cells of strain LA399T grew in the medium containing 0-10.0 % of NaCl (w/v; optimum 3.0-5.0 %), pH 6.5-8.0 (optimum 7.0) and 20-40 °C (optimum 37 °C). Aesculin, gelatin, starch and Tween 80 were hydrolysed. Strain LA399T was closely related to Gracilimonas halophila WDS2C40T (97.0 % sequence similarity), Gracilimonas mengyeensis YIM J14T (96.4 %), Gracilimonas rosea CL-KR2T (96.4 %) and Gracilimonas tropica DSM 19535T (96.0 %), and exhibited equal or less than 96.0 % sequence similarity to other type strains of species with validly published names. Phylogenetic analyses revealed that strain LA399T clustered with the clade comprising the Gracilimonas species and formed an independent lineage. Strain LA399T contained menaquinone 7 as the sole isoprenoid quinone and iso-C15 : 0, anteiso-C15 : 0, summed feature 3 (C16 : 1ω7c/C16 : 1ω6c) and summed feature 9 (iso-C17 : 1ω9c/10-methyl C16 : 0) as the predominant cellular fatty acids. The major polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, one unidentified phospholipid and three unidentified glycolipids. The DNA G+C content was 45.3 mol%. According to the phylogenetic, chemotaxonomic and phenotypic data, it represents a novel species of the genus Gracilimonas, for which the name Gracilimonas amylolytica is proposed. The type strain is LA399T (=CGMCC 1.16248T=KCTC 52885T).