Marinobacter denitrificans sp. nov., isolated from marine sediment of southern Scott Coast, Antarctica.

A novel bacterium, designated JB02H27T, was isolated from marine sediment collected from the southern Scott Coast, Antarctica. Cells were Gram-stain-negative, facultatively anaerobic, polar-flagellated and motile rods. Growth occurred at 4-45 °C, at pH 7.0-9.0 and with 3-25 % (w/v) NaCl. Phylogenetic trees based on 16S rRNA gene sequences showed that strain JB02H27T consistently fell within the genus Marinobacter and formed a clade together with Marinobacter algicola DG893T (98.8 % similarity), Marinobacter confluentis KCTC 42705T (98.4 %), Marinobacter salarius R9SW1T (98.4%) and Marinobacter halotolerans CP12T (97.9 %), which were subsequently used as reference strains for comparisons of phenotypic and chemotaxonomic characteristics. Average nucleotide identity values between strain JB02H27T and the four related type strains were 80.9, 76.6, 81.9 and 76.3 %, respectively. The major fatty acids were summed feature 3, C16 : 0, C18 : 1 ω9c and C16 : 0 N alcohol. The polar lipids included phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, and an unidentified phospholipid, aminolipid, aminophospholipid and glycolipids. The sole respiratory quinone was ubiquinone-9. The DNA G+C content was 56.9 mol%. Based on the genomic, phylogenetic, phenotypic and chemotaxonomic analysis, we propose that strain JB02H27T represents a novel species of the genus Marinobacter, for which the name Marinobacter denitrificans sp. nov. is proposed. The type strain is JB02H27T (=GDMCC 1.1528T=KCTC 62941T).

Transfer of Sphingorhabdus marina, Sphingorhabdus litoris, Sphingorhabdus flavimaris and Sphingorhabdus pacifica corrig. into the novel genus Parasphingorhabdus gen. nov. and Sphingopyxis baekryungensis into the novel genus Novosphingopyxis gen. nov. within the family Sphingomonadaceae.

During a phylogenetic analysis of Sphingorhabdus and its closely related genera in the family Sphingomonadaceae, we found that the genus Sphingorhabdus and the species Sphingopyxis baekryungensis might not be properly assigned in the taxonomy. Phylogenetic, phenotypic and chemotaxonomic characterizations clearly showed that the genus Sphingorhabdus should be reclassified into two genera (Clade I and Clade II), for which the original genus name, Sphingorhabdus, is proposed to be retained only for Clade I, and a new genus named as Parasphingorhabdus gen. nov. is proposed for Clade II with four new combinations: Parasphingorhabdus marina comb. nov., Parasphingorhabdus litoris comb. nov., Parasphingorhabdus flavimaris comb. nov. and Parasphingorhabdus pacifica comb. nov. Moreover, Sphingopyxis baekryungensis should represent a novel genus in the family Sphingomonadaceae, for which the name Novosphingopyxis gen. nov. is proposed, with a combination of Novosphingopyxis baekryungensis comb. nov. The study provides a new insight into the taxonomy of closely related genera in the family Sphingomonadaceae.

Chitinophaga flava sp. nov., isolated from monsoon evergreen broad-leaved forest soil.

A Gram-stain-negative, aerobic, non-motile strain, K3CV102501T, was isolated from a soil sample collected from the monsoon evergreen broad-leaved forest of Dinghushan Biosphere Reserve located in Guangdong Province, PR China. The primal colony of strain K3CV102501T was very similar to the fruiting body of myxobacteria on the original isolation plates. Young cultures of strain K3CV102501T contained long (2-4×0.4-0.5 µm) filamentous cells and divided into rod shapes (0.7-1.0×0.6-0.8 µm) after 4 days of incubation at 28 °C. Strain K3CV102501T grew at pH 6.0-9.5 (optimum, pH 6.5-7.5) and 7-42 °C (optimum, 28-35 °C). Phylogenetic analysis based on its 16S rRNA gene sequence showed that strain K3CV102501T belonged to the genus Chitinophagaand showed the highest similarity to C.hitinophaga jiangningensis JCM 19354T (96.9 %). The DNA G+C content of the type strain was 46.6 mol%. The major fatty acids (>10 %) were iso-C15 : 0, C16 : 1ω5c and iso-C17 : 0 3-OH. The major polar lipids were phosphatidylethanolamine and an unidentified aminolipid. Menaquinone-7 was the predominant quinone. The phenotypic, chemotaxonomic and phylogenetic data clearly showed that strain K3CV102501T represents a novel species of the genus Chitinophaga, for which the name Chitinophaga flava sp. nov. is proposed. The type strain is K3CV102501T (=KCTC 62435T=GDMCC 1.1325T).

Antarcticibacterium flavum gen. nov., sp. nov., isolated from marine sediment.

A Gram-stain-negative, strictly aerobic, yellow-pigmented, non-gliding, oval to rod-shaped bacterial strain, designated JB01H24T, belonging to the family Flavobacteriaceae, was isolated from marine surface sediment collected from the Ross Sea, Antarctica. Strain JB01H24T grew at 4-40 °C (optimum 25-30 °C), pH 7.0-9.0 (optimum 7.5-8.0), and in the presence of 0-8 % NaCl (optimum 3 %, w/v). Phylogenetic analysis based on 16S rRNA gene sequences showed that strain JB01H24T formed an independent linkage within the family Flavobacteriaceae and was closely related with the genus Gillisia. Strain JB01H24T exhibited 16S rRNA gene sequence similarities of 95.3-91.5 % and 94.9-94.0 % to the type strains of the genera Gillisia and Salinimicrobium, respectively. The major fatty acids (>5 %) were iso-C15 : 0, summed feature 3 (C16 : 1ω6c and/or C16 : 1ω7c), anteiso-C15 : 0, iso-C15 : 1 G and summed feature 9 (iso-C17 : 1ω9c and/or 10-methyl C16 : 0). The major polar lipids were phosphatidylethanolamine, seven unidentified lipids, two unidentified aminolipids and an unidentified aminophospholipid. Strain JB01H24T contained menaquinone-6 as the only ubiquinone. The DNA G+C content was 42.4 mol%. On the basis of phylogenetic, physiological and chemotaxonomic properties, strain JB01H24T is considered to represent a novel species of a new genus within the family Flavobacteriaceae, for which the name Antarcticibacterium flavum gen. nov., sp. nov. is proposed. The type strain of Antarcticibacterium flavum is JB01H24T (=GDMCC 1.1229T=KCTC 52984T).

Gramella antarctica sp. nov., isolated from marine surface sediment.

A Gram-stain-negative, aerobic, yellow-coloured, motile by gliding, rod-shaped bacterial strain, designated R17H11T, was isolated from surface sediment collected from the Ross Sea, Antarctica. Growth optimally occurred at 25-30 °C, at pH 7.0-7.5 and in the presence of 3 % NaCl (w/v). Phylogenetic trees based on 16S rRNA gene sequences indicated that strain R17H11T clustered together with Gramella flava JLT2011T and fell within the genus Gramella. Strain R17H11T shared the highest 16S rRNA gene similarities (96.1 and 96.0 %) with the type strains of Gramella forsetii and G. flava, and 92.6-95.5 % similarities with those of other known Gramella species. Strain R17H11T contained menaquinone-6 as the only isoprenoid quinone. The major fatty acids (>5 %) were summed feature 3 (17.5 %, comprising C16 : 1ω7c and/or C16 : 1ω6c), iso-C15 : 0 (14.0 %), summed feature 9 (11.8 %, comprising 10-methyl C16 : 0 and/or iso-C17 : 1ω9c), iso-C17 : 0 3-OH (11.8 %), iso-C16 : 0 (7.4 %), C17 : 1ω6c (6.9 %) and anteiso-C15 : 0 (5.1 %). The major polar lipids were phosphatidylethanolamine, four unidentified lipids, an unidentified aminolipid, an unidentified aminophospholipid and an unidentified glycolipid. The DNA G+C content of strain R17H11T was 38.6 mol%. On the basis of the phylogenetic, physiological and chemotaxonomic characteristics, strain R17H11T represents a novel species in the genus Gramella, for which the name Gramellaantarctica sp. nov. is proposed. The type strain of the novel species is R17H11T (=GDMCC 1.1208T=KCTC 52925T).

Arenibacter catalasegens sp. nov., isolated from marine surface sediment, and emended description of the genus Arenibacter.

A Gram-staining-negative, aerobic, non-motile, rod-shaped bacterium, designated as P308H10T, was isolated from surface sediment of the Southern Indian Ocean. Growth occurred at 4-36 °C (optimum 20-25 °C), pH 6.0-8.5 (optimum 7.5-8.0) and in the presence of 1-8 % (w/v) NaCl (optimum 2-3 %). Phylogenetic analysis based on 16S rRNA gene sequences showed that strain P308H10T lies within the clade of members of the genus Arenibacter and is closely related to Arenibacterhampyeongensis HP12T (98.0 %), Arenibacterechinorum KMM 6032T (98.4 %), Arenibacterpalladensis LMG 21972T (97.9 %), Arenibactertroitsensis KMM 3674T (97.9 %) and 'Arenibacter algicola' TG409 (98.1 %). The average nucleotide identity and digital DNA-DNA hybridization values between strain P308H10T and the five reference strains were 85.9-80.6 % and 30.2-23.6 %, respectively. The major fatty acids (>10 %) of strain P308H10T were summed feature 3, iso-C17 : 0 3-OH, iso-C15 : 1 G and iso-C15 : 0. The major polar lipids comprised phosphatidylethanolamine, five unidentified aminolipids and four unidentified lipids. The only respiratory quinone was menaquinone-6. The genomic DNA G+C content was 38.2 mol%. On the basis of the phenotypic, phylogenetic and chemotaxonomic data presented, strain P308H10T represents a novel species of the genus Arenibacter, for which the name Arenibacter catalasegens sp. nov. is proposed. The type strain is P308H10T (=GDMCC 1.1230T=KCTC 52983T). An emended description of the genus Arenibacter is also proposed.

Chitinophaga varians sp. nov., isolated from forest soil.

A Gram-stain-negative, aerobic, non-motile bacterium, designated strain 10-7W-9003T, was isolated from the forest soil of Limushan National Forest Park, south-east China (19° 10' 42″ N, 109° 44' 45″ E). Strain 10-7W-9003T showed a shape change during the course of culture from long filamentous cells (5-10×0.4-0.5 µm) at 5-36 h, to rod shaped (1.0-1.5×0.5-0.7 µm) with inoculation after 2 days. It grew optimally at 28-30 °C and pH 6.5-7.5. On the basis of 16S rRNA gene sequence analysis, it belongs to the genus Chitinophaga and is most closely related to Chitinophaga eiseniae KACC 13774T and Chitinophaga qingshengii JCM 30026T, with 16S rRNA gene sequences similarities of 98.8 and 98.3 %, respectively. However, the DNA-DNA hybridization study showed that strain 10-7W-9003T shared relatively low relatedness values with KACC 13774T (21.8 %) and JCM 30026T (20.4 %), respectively. The major fatty acids (>10 %) were iso-C15 : 0, C16 : 1ω5c and iso-C17 : 0 3-OH. The genomic DNA G+C content was 50.7 mol%. It contained MK-7 as the major quinone. The phenotypic, chemotaxonomic and phylogenetic data clearly showed that strain 10-7W-9003T represents a novel species of the genus Chitinophaga, for which the name Chitinophaga varians sp. nov. is proposed. The type strain is 10-7W-9003T (=GDMCC 1.1252T=KACC 19415T=KCTC 52926T).

Arenibacter antarcticus sp. nov., isolated from marine sediment.

A strictly aerobic, Gram-stain-negative, pale-golden, rod-shaped bacterium, designated as R18H21T, was isolated from marine sediment collected from the Ross Sea, Antarctica. Strain R18H21T grew at 4-40 °C (optimum 25 °C), at pH 6.3-9.2 (optimum 7.5-8.5) and in 0.5-6 % (w/v) NaCl (optimum 2 %). Phylogenetic analyses based on 16S rRNA gene sequences showed that strain R18H21T belonged to the genus Arenibacter, with the highest similarity to two type strains, Arenibacter latericius KMM 426T (96.6 %) and Arenibacter certesii KMM 3941T (96.6 %), and lower similarities (95.2-95.9 %) to five other members of the genus Arenibacter. The major fatty acids were iso-C17 : 0 3-OH, Summed Feature 3 (C16 : 1ω6c and/or C16 : 1ω7c), iso-C15 : 0, iso-C15 : 1 G. The major polar lipids were phosphatidylethanolamine, an unidentified aminolipid and an unidentified phospholipid. The respiratory quinone of strain R18H21T was menaquinone-6. The DNA G+C content was 40.0 mol%. Based on phylogenetic, physiological and chemotaxonomic features, strain R18H21T has been classified as a novel species in the genus Arenibacter, for which the name Arenibacterantarcticus sp. nov. is proposed. The type strain of the novel species is R18H21T (=GDMCC 1.1159T=KCTC 52924T).

Aurantimonas aggregata sp. nov., isolated from deep-sea sediment.

A novel bacterium, designated R14M6T, was isolated from deep-sea sediment collected from the Ross Sea, Antarctica. Cells are Gram-stain-negative, aerobic, pale yellow, short-rod-shaped, polar-flagellated and aggregate-forming. Growth occurs at 4-36 °C, pH 6.0-8.3, and in 1-15 % (w/v) NaCl. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain R14M6T clustered together with Aurantimonas endophytica EGI6500337T and fell within the genus Aurantimonas. The 16S rRNA gene sequence of strain R14M6T shared similarity with A. endophytica EGI6500337T (99.15 %), A. manganoxydans DSM 21871T (97.73 %), A. coralicida DSM 14790T (97.58 %) and 'A. litoralis' KCTC 12094 (97.51 %). The DNA-DNA relatedness values between strain R14M6T and A. endophytica EGI6500337T, A. coralicida DSM 14790T, A. manganoxydans DSM 21871T and 'A. litoralis' KCTC 12094 were 36.9±4.5, 27.6±2.8, 29.6±1.2 and 25.2±2.4 % respectively. The major fatty acid of strain R14M6T was C18 : 1ω7c. The major polar lipids were phosphatidylcholine, diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine and an unidentified aminolipid. Strain R14M6T contained Q-10 as the dominant isoprenoid quinone. The DNA G+C content of strain R14M6T was 67.4 mol%. Based on the phylogenetic, physiological and chemotaxonomic analyses, strain R14M6T represents a novel species of the genus Aurantimonas, for which the name Aurantimonas aggregata sp. nov. is proposed. The type strain is R14M6T (=GDMCC 1.1202T=KCTC 52919T).

Culture-Dependent and -Independent Analyses Reveal the Diversity, Structure, and Assembly Mechanism of Benthic Bacterial Community in the Ross Sea, Antarctica.

The benthic bacterial community in Antarctic continental shelf ecosystems are not well-documented. We collected 13 surface sediments from the Ross Sea, a biological hotspot in high-latitude maritime Antarctica undergoing rapid climate change and possible microflora shift, and aimed to study the diversity, structure and assembly mechanism of benthic bacterial community using both culture-dependent and -independent approaches. High-throughput sequencing of 16S rRNA gene amplicons revealed 370 OTUs distributed in 21 phyla and 284 genera. The bacterial community was dominated by Bacteroidetes, Gamma- and Alphaproteobacteria, and constituted by a compact, conserved and positively-correlated group of anaerobes and other competitive aerobic chemoheterotrophs. Null-model test based on ßNTI and RCBray indicated that stochastic processes, including dispersal limitation and undominated fractions, were the main forces driving community assembly. On the other hand, environmental factors, mainly temperature, organic matter and chlorophyll, were significantly correlated with bacterial richness, diversity and community structure. Moreover, metabolic and physiological features of the prokaryotic taxa were mapped to evaluate the adaptive mechanisms and functional composition of the benthic bacterial community. Our study is helpful to understand the structural and functional aspects, as well as the ecological and biogeochemical role of the benthic bacterial community in the Ross Sea.

Grading of avascular necrosis of the femoral head and early imaging diagnosis / 中华放射学杂志

Objective To study the staging and early imaging diagnosis of avascular necrosis of the femoral head (ANFH). Methods X ray, CT, and low field MRI were conducted and grading was performed in bilateral femoral head of 62 cases. Rank sum H test and sensitivity were completed. Results The entire cases were diagnosed as early ANFH by X ray film in 91 places. Stage I showed osteoporosis and osteosclerosis in 46 places. Stage Ⅱ showed osteosclerosis and cystic hyalomere in 45 places. 56 cases of early ANFH were discovered by CT in 86 places. Stage I showed stelliform sign distortion and osteoporosis and osteosclerosis in 34 places. Stage Ⅱ showed osteosclerosis and cystic hyalomere in 30 places. Stage Ⅲ showed meniscus sign in 22 places. Low field MRI displayed only 44 cases (73 places) of early ANFH. Stage I displayed the macular shape low or high signal intensity on T1 weighted and GRL image in 30 places. Stage Ⅱ displayed the irregular shape low or equal or high signal on T1 weighted and GRL image in 23 places. Stage Ⅲ displayed the flaky low signal and curve high signal on T1 weighted and GRL image in 20 places. Rank sum H test and sensitivity compare were striking ( P