NMR study of 17O from H217O in human erythrocytes

Human erythrocytes were incubated in a Ringer's solution enriched with 10–18% H₂¹⁷O. The longitudinal relaxation time (T₁) of the ¹⁷O was determined separately in samples of red cell suspesions, packed cells, and supernatant. The longitudinal relaxation of ¹⁷O in erythrocyte suspensions was non-exponential, reflecting water exchange across the cell membranes as well as relaxation processes inside and outside the cell.The T₁ of intracellular ¹⁷O is 4–5 times shorter than in the supernatant, similar to the enhancement of proton relaxation by hemoglobin in erythrocytes and free solution at the frequency applied (8.13 MHz). This datum is consistent with the thesis that hemoglobin modifies the NMR relaxation behavior of water inside cells and in free solution in the same way.The rate constant

for water exchange was calculated to be 60 and 107 s⁻¹ at 25 and at 37° C, respectively. The apparent activation energy for

over the temperature range 23–37° C was 8.7±1.0 kcal/mole.     

Cell volume dependence of 1H spin-echo NMR signals in human erythrocyte suspensions: The influence of in situ field gradients

The ¹H spin-echo NMR signal amplitudes and intensities of low molecular weight solutes in the cytoplasm and extracellular fluid of suspensions of human erythrocytes were shown to depend on the osmotic pressure of the media. At low osmotic pressure (220 mosM/kg) freeze-thaw lysis of the cells resulted in signal enhancement which was greatest for extracellular molecules, but both intra- and extracellular species were almost equally enhanced at 580 mosM/kg. This effect is due to field gradients formed at cell boundaries as a result of differences in magnetic susceptibility between the medium and the cytoplasm. T₂ values measured using the Carr-Purcell-Meiboom-Gill pulse sequence, with τ = 0.0003 s, depended little on cell volume and absolute changes in volume magnetic susceptibility were also small. The mean field gradients, calculated from data obtained on cell suspensions at different osmotic pressures, were in the range 0.25–1.98 G/cm and 0.89–2.09 G/cm for intra- and extracellular compartments, respectively. The maintenance of isotonicity of the extracellular fluid during metabolic studies of cell suspensions is important in order to avoid artefacts in the determination of metabolite concentrations when using the spin-echo technique. Conversely it may be possible to perform transport measurements using spin-echo NMR to monitor the cell volume changes which occur during the transmembrane migration of molecules.     

Superoxide dismutase and the oxygen enhancement of radiation lethality

Escherichia coli B were more susceptible to radiation lethality and showed a greater oxygen enhancement ratio when exposed in dilute suspension (1 × 10⁵ cells/ml) than when exposed in dense suspensions (1 × 10⁹ cells/ml). The oxygen enhancement, seen with dilute suspensions, was diminished by superoxide dismutase, catalase, mannitol, or histidine. Heat-denatured superoxide dismutase was without effect. The results are interpreted as indicating a role for O₂^? plus H₂O₂ in the oxygen enhancement of radiation lethality, and a scheme is proposed which is consistent with the observations.     

<Emphasis Type="Italic">Azohydromonas riparia</Emphasis> sp. nov. and <Emphasis Type="Italic">Azohydromonas ureilytica</Emphasis> sp. nov. isolated from a riverside soil in South Korea

White and pale yellow coloured bacteria were isolated from the riverside soil, Daejeon, South Korea, and were designated UCM-11^T, UCM-F25, and UCM-80^T. We found that all strains were able to reduce nitrate, and the cells were aerobic and motile. The DNA G+C contents of UCM-11^T, UCM-F25, and UCM-80^T were between 68.9 to 71.2 mol% and the main ubiquinone was observed as Q-8. Based on16S rRNA gene sequences, strains UCM-11^T and UCM-F25 were found to closely match with Azohydromonas australica IAM 12664^T (98.48–98.55%), and the strain UCM-80^T was the closest match with Azohydromonas lata IAM 12599^T (98.34%). The presence of summed feature 3 (C_16:1 ω7c and/or C_16:1 ω6c), C_16:0, summed feature 8 (C_18:1 ω7c and/or C_18:1 ω6c) as well as twokinds of hydroxyfatty acids consisting of C_10:0 3-OH and C_12:0 2-OH, and branched fatty acids containing C_16:0 iso and C_17:0 cyclo were detected in all the strains. Phosphatidylethanolamine was a major polar lipid. DNA–DNA relatedness confirmed UCM-11^T, UCM-F25 and UCM-80^T as novel members of the genus Azohydromonas. Based on the morphological, physiological, biochemical and genotypic characteristics, we suggest that strains UCM-11^T, UCM-F25, and UCM-80^T represent novel species within the genus Azohydromonas. The names Azohydromonas riparia sp. nov., and Azohydromonas ureilytica sp. nov. are proposed for the type strains UCM-11^T (=KACC 18570^T =NBRC 111646^T) and UCM-80^T (=KACC 18576^T =NBRC 111658^T), respectively.     

Effect of oxygen concentration on trasverse water proton relaxation times in erythrocytes homozygous and heterozygous for hemoglonin S.

The transverse water proton relaxation times (T₂) of erythrocytes homozygous and heterozygous for hemoglobin S have been measured as a function of oxyhemoglobin concentration at 37 °C. An immediate decrease in T₂ is observed in S/S erythrocytes as the amount of oxyhemoglobin is decreased and the maximum change is observed at 50% deoxyhemoglobin S. In heterozygous erythrocytes, the T₂ remains unchanged until a critical level of deoxyhemoglobin is attained. The critical level of deoxyhemoglobin is a function of the percentage of hemoglobin S in the heterozygous erythrocytes. A Hill plot of the data obtained from S/S erythrocytes gives an n value of around 2.4. These results suggest that the measurement of T₂ is sensitive to the very early stages of the polymerization process. This suggestion is supported by calculations; our T₂ measurements are sensitive to a range of correlation times expected for hemoglobin monomers at one extreme and linear polymers of seven hemoglobin molecules at the other extreme.     

Methanomethylovorans uponensis sp. nov., a methylotrophic methanogen isolated from wetland sediment

A novel mesophilic, methylotrophic, methanogenic archaeon, designated strain EK1^T, was enriched and isolated from wetland sediment. Phylogenetic analysis showed that strain EK1^T was affiliated with the genus Methanomethylovorans within the family Methanosarcinaceae, and shared the highest 16S rRNA and methyl-coenzyme M reductase alpha-subunit gene sequence similarity with the type strain of Methanomethylovorans hollandica (98.8 and 92.6 %, respectively). The cells of strain EK1^T were observed to be Gram-negative, non-motile and irregular cocci that did not lyse in 0.1 % (w/v) sodium dodecyl sulfate. Methanol, mono-, di- and trimethylamine, dimethyl sulfide and methanethiol were found to be used as catabolic and methanogenic substrates, whereas H₂/CO₂, formate, 2-propanol and acetate were not. Growth was observed at 25–40 °C (optimum, 37 °C), at pH 5.5–7.5 (optimum, pH 6.0–6.5) and in the presence of 0–0.1 M NaCl (optimum, 0 M). Growth and methane production rates were stimulated in the presence of H₂/CO₂ although methane production and growth yields were not significantly affected; acetate, formate, 2-propanol and CO/CO₂/N₂ did not affect methane production. CoCl₂ (0.6–2.0 μM) and FeCl₂ (25 mg/l) stimulated growth, while yeast extract and peptone did not. The DNA–DNA hybridization experiment revealed a relatedness of <20 % between EK1^T and the type strains of the genus Methanomethylovorans. The DNA G+C content of strain EK1^T was determined to be 39.2 mol%. Based on the polyphasic taxonomic study, strain EK1^T represents a novel species belonging to the genus Methanomethylovorans, for which the name Methanomethylovorans uponensis sp. nov. is proposed. The type strain is strain EK1^T(=NBRC 109636^T = KCTC 4119^T = JCM 19217^T).     

Actibacterium atlanticum sp. nov., isolated from surface seawater of the Atlantic Ocean

A taxonomic study was carried out on strain 22II-S11-z10^T, which was isolated from the surface seawater of the Atlantic Ocean. The bacterium was found to be Gram-stain negative, oxidase and catalase positive, oval- to rod-shaped and non-motile. Growth was observed at salinities of 0.5–9 % and at temperatures of 10–41 °C. The isolate can reduce nitrate to nitrite, degrade gelatin and aesculin, but can not degrade Tween 80. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain 22II-S11-z10^T belongs to the genus Actibacterium, with the highest sequence similarity to the type strain Actibacterium mucosum CECT 7668^T (97.3 %). The DNA–DNA hybridization estimate value between strain 22II-S11-z10^T and A. mucosum CECT 7668^T was 19.30 ± 2.29 %. The principal fatty acids were identified as Summed Feature 8 (C_18:1 ω7c/ω6c as defined by the MIDI system, 75.2 %) and Summed Feature 3 (C_16:1 ω7c/ω6c, 6.9 %). The G+C content of the chromosomal DNA was determined to be 59.0 mol%. The respiratory quinone was determined to be Q-10 (100 %). Phosphatidylglycerol, phosphatidylcholine, two phospholipids, two aminolipids and two lipids were identified in the polar lipids. The combined genotypic and phenotypic data show that strain 22II-S11-z10^T represents a novel species within the genus Actibacterium, for which the name Actibacterium atlanticum sp. nov. is proposed, with the type strain 22II-S11-z10^T (=MCCC 1A09298^T = LMG 27158^T).     

<Emphasis Type="Italic">Spirosoma flavus</Emphasis> sp. nov., a novel bacterium from soil of Jeju Island

A novel, Gram-staining negative, yellow pigmented bacterial strain, designated 15J11-2^T, was isolated from soil sample on Jeju Island, Republic of Korea. The strain was subjected to a taxonomic study using a polyphasic approach. The strain was able to grow at temperature range from 10°C to 30°C, pH 7–8, and in presence of 0–1% (w/v) NaCl. Comparative 16S rRNA gene sequence analysis showed that strain 15J11-2^T belongs to the genus Spirosoma and levels of 16S rRNA gene sequence similarity ranged from 91.5% to 89.8%. The genomic DNA G + C content of strain 15J11-2^T was 46.0 mol%. The isolate contained phosphatidylethanolamine and an unidentified aminophospholipid as the main polar lipids, menaquinone MK-7 as the predominant respiratory quinone, and summed feature 3 (C_16:1ω6c/C_16:1ω7c; 39.4%), C_16:1ω5c (27.1%), and C_16:0 (13.0%) as the major fatty acids, which supported the affiliation of strain 15J11-2^T to the genus Spirosoma. The results of physiological and biochemical tests allowed genotypic and phenotypic differentiation of strain 15J11-2^T from recognized Spirosoma species. On the basis of its phenotypic properties, genotypic distinctiveness, chemotaxonomic features, strain 15J11-2^T represents a novel species of the genus Spirosoma, for which the name Spirosoma flavus sp. nov. is proposed. The type strain is 15J11-2^T (= KCTC 52026^T = JCM 31998^T).     

Halorubrum rubrum sp. nov., an extremely halophilic archaeon from a Chinese salt lake

Two halophilic archaeal strains, YC87^T and YCA11, were isolated from Yuncheng salt lake in Shanxi, China. Cells of the two strains were observed to be pleomorphic rod-shaped, stained Gram-negative and produced red-pigmented colonies. Strain YC87^T was able to grow at 20–50 °C (optimum 37 °C), at 1.4–4.8 M NaCl (optimum 2.1 M NaCl), at 0.05–1.0 M MgCl₂ (optimum 0.3 M MgCl₂) and at pH 6.0–9.0 (optimum pH 7.0) while strain YCA11 was able to grow at 20–50 °C (optimum 37 °C), at 2.1–4.8 M NaCl (optimum 3.1 M NaCl), at 0.01–0.7 M MgCl₂ (optimum 0.1 M MgCl₂) and at pH 6.0–9.0 (optimum pH 7.5). The cells of both isolates were observed to lyse in distilled water. The minimum NaCl concentrations that prevented cell lysis were determined to be 8 % (w/v) for strain YC87^T and 12 % (w/v) for strain YCA11. The major polar lipids of the two strains were identified as phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester, phosphatidylglycerol sulfate and one major glycolipid chromatographically identical to sulfated mannosyl glucosyl diether; another major glycolipid and trace amounts of several unidentified lipids were also detected. The 16S rRNA gene sequences of the two strains were 99.8 % identical, showing 93.2–98.2 % similarity to members of the genus Halorubrum of the family Halobacteriaceae. The rpoB′ gene similarity between strains YC87^T and YCA11 was 99.3 % and showed 87.5–95.2 % similarity to the closest relative members of the genus Halorubrum. The DNA G+C content of strains YC87^T and YCA11 were determined to be 64.9 and 64.5 mol%, respectively. The DNA–DNA hybridization value between strain YC20^T and strain YC77 was 87 % and the two strains showed low DNA–DNA relatedness with Halorubrum cibi JCM 15757^T and Halorubrum aquaticum CGMCC 1.6377^T, the most related members of the genus Halorubrum. The phenotypic, chemotaxonomic and phylogenetic properties suggest that strains YC87^T and YCA11 represent a novel species of the genus Halorubrum, for which the name Halorubrum rubrum sp. nov. is proposed. The type strain is YC87^T (=CGMCC 1.12124^T = JCM 18365^T).     

<Emphasis Type="Italic">Spirosoma pomorum</Emphasis> sp. nov., isolated from apple orchard soil

A Gram-negative, motile, rod-shaped, aerobic bacterial strain, designated S7-2-11^T, was isolated from apple orchard soil from Gyeongsangnam-do Province, Republic of Korea, and was characterized taxonomically using a polyphasic approach. 16S rRNA gene sequence analysis indicated that strain S7-2-11^T belongs to the family Cytophagaceae in phylum Bacteroidetes, and is closely related to Spirosoma luteolum 16F6E^T (94.2% identity), Spirosoma knui 15J8-12^T (92.7%), and Spirosoma linguale DSM 74^T (91.0%). The G + C content of the genomic DNA of strain S7-2-11^T was 49.8 mol%. Strain S7-2-11^T contained summed feature 3 (C_16:1 ω7c/C_16:1 ω6c; 35.1%), C_16:1 ω5c (22.4%), C_15:0 iso (13.9%), and C_17:0 iso 3-OH (10.6%) as major cellular fatty acids, and MK-7 as the predominant respiratory quinone. The main polar lipids were phosphatidylethanolamine, an unidentified aminophospholipid, and two unidentified polar lipids. Phenotypic and chemotaxonomic data supported the affiliation of strain S7-2-11^T with the genus Spirosoma. The results of physiological and biochemical tests showed the genotypic and phenotypic differentiation of the isolate from recognized Spirosoma species. On the basis of its phenotypic properties, genotypic distinctiveness, and chemotaxonomic features, strain S7-2-11^T represents a novel species of the genus Spirosoma, for which the name Spirosoma pomorum sp. nov. is proposed. The type strain is S7-2-11^T (= KCTC 52726^T = JCM 32130^T).     

Rubrimonas shengliensis sp. nov. and Polymorphum gilvum gen. nov., sp. nov., novel members of Alphaproteobacteria from crude oil contaminated saline soil

Four bacterial strains were isolated from a crude oil contaminated saline soil in Shengli Oilfield, China. Strains SL014B-28A2^T and SL014B-80A1 were most closely related to Rubrimonas cliftonensis OCh 317^T, while strains SL003B-26A1^T and SL003B-26A2 were most closely related to but readily different from the species in the Pannonibacter-Labrenzia-Roseibium-Stappia cluster. The major fatty acids were C_18:1ω7c, C_16:0, C_18:0 and 11-Methyl C_18:1ω7c, and C_18:1ω7c, 11-Methyl C_18:1ω7c and C_18:0, respectively, for these two groups of isolates. Q-10 was the predominant ubiquinone. The G + C contents of genomic DNA of the four isolates were 67.9, 69.7, 65.6 and 65.6 mol%. Based on the polyphasic taxonomic characteristics, strains SL014B-28A2^T and SL014B-80A1 represented a novel species of the genus Rubrimonas, for which the name Rubrimonas shengliensis sp. nov. is proposed, with strain SL014B-28A2^T (=LMG 26072^T = CGMCC 1.9170^T) as the type strain. Isolates SL003B-26A1^T and SL003B-26A2 represented a novel genus and species of the family Rhodobacteraceae, for which the name Polymorphum gilvum gen. nov., sp. nov. is proposed, with strain SL003B-26A1^T (=LMG 25793^T = CGMCC 1.9160^T) as the type strain.     

Hemoglobin-water interactions in normal and sickle erythrocytes by proton magnetic resonance T1ϱ measurements

The dependence of the water proton magnetic resonance spin-lattice relaxation rate (T_1?^?1) in the rotating frame on the strength of the spin-locking (H₁) field has been investigated for packed oxy and deoxy normal and sickle erythrocytes at temperatures from 9 to 40 °C. The T_1?^?1 of oxy or deoxy normal erythrocytes shows no dependence on H₁ up to ~7 G at any temperature studied. On the other hand, T_1?^?1 decreases from about 40 s^?1 to 15 s^?1 (H₁ from 0 to ~7 G) for deoxygenated packed sickle cells at 40 °C. The magnitude of this variation of T_1?^?1 with H₁ decreases with decreasing temperature. Oxy packed sickle cells also show a dependence of T_1?^?1 on H₁ but the magnitude is <10% of that of the deoxygenated samples. These results suggest that water proton T_1?^?1 measurements are a sensitive probe of hemoglobin S polymerization and provide a novel technique for the study of slow water motions in these systems. The T_1?^?1 results are compared with low frequency T₁^?1 results of other investigators on hemoglobin S solutions. Analysis of the data suggests that water proton motions with correlation times of the order of 10^?5 s are present in the deoxygenated sickle cell samples at temperatures above 10 °C.     

Aquimarina atlantica sp. nov., isolated from surface seawater of the Atlantic Ocean

A taxonomic study was carried out on strain 22II-S11-z7^T, which was isolated from the surface seawater of the Atlantic Ocean. The bacterium was found to be Gram-negative, oxidase negative and catalase positive, long-rod shaped, and gliding. Growth was observed at salinities of 1–5 % and at temperatures of 10–41 °C. The isolate was capable of hydrolysing gelatin and Tween 80 and able to reduce nitrate to nitrite, but unable to degrade aesculin. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain 22II-S11-z7^T belongs to the genus Aquimarina, with highest sequence similarity to Aquimarina megaterium XH134^T (98.31 %), followed by Aquimarina macrocephali JAMB N27^T (96.59 %); other species of the genus Aquimarina shared 93.63–96.08 % sequence similarity. The ANI value between strain 22II-S11-z7^T and A. megaterium XH134^T was found to be 91.86–91.81 %. The DNA–DNA hybridization estimated value between strain 22II-S11-z7^T and A. megaterium XH134^T was 47.7 ± 2.6 %. The principal fatty acids were identified as Summed Feature 3 (C_16:1 ω7c/ω6c, as defined by the MIDI system; 8.1 %), SummedFeature 9 (iso-C_17:1 ω7c/C_16:110-methyl; 6.8 %), iso-C_15:0 G (11.3 %), iso-C_15:0 (24.9 %), iso-C_16:0 (5.7 %), C_16:0 (5.2 %), iso-C_15:0 3OH (6.4 %) and iso-C_17:0 3OH (21.5 %). The G+C content of the chromosomal DNA was determined to be 32.99 mol %. The respiratory quinone was determined to be MK-6 (100 %). Phosphatidylethanolamine, two unidentified aminolipids, five unidentified phospholipids and two unidentified lipids were found to be present. The combined genotypic and phenotypic data show that strain 22II-S11-z7^T represents a novel species within the genus Aquimarina, for which the name Aquimarina atlantica sp. nov. is proposed, with the type strain 22II-S11-z7^T (=MCCC 1A09239^T = KCTC 42003^T).     

T Cell Hypo-Responsiveness against Leishmania major in MAP Kinase Phosphatase (MKP) 2 Deficient C57BL/6 Mice Does Not Alter the Healer Disease Phenotype

We have recently demonstrated that MAP kinase phosphatase 2 (MKP-2) deficient C57BL/6 mice, unlike their wild-type counterparts, are unable to control infection with the protozoan parasite Leishmania mexicana. Increased susceptibility was associated with elevated Arginase-1 levels and reduced iNOS activity in macrophages as well as a diminished T_H1 response. By contrast, in the present study footpad infection of MKP-2^−/− mice with L. major resulted in a healing response as measured by lesion size and parasite numbers similar to infected MKP-2^+/+ mice. Analysis of immune responses following infection demonstrated a reduced T_H1 response in MKP-2^−/− mice with lower parasite specific serum IgG2b levels, a lower frequency of IFN-γ and TNF-α producing CD4⁺ and CD8⁺ T cells and lower antigen stimulated spleen cell IFN-γ production than their wild-type counterparts. However, infected MKP-2^−/− mice also had similarly reduced levels of antigen induced spleen and lymph node cell IL-4 production compared with MKP-2^+/+ mice as well as reduced levels of parasite-specific IgG1 in the serum, indicating a general T cell hypo-responsiveness. Consequently the overall T_H1/T_H2 balance was unaltered in MKP-2^−/− compared with wild-type mice. Although non-stimulated MKP-2^−/− macrophages were more permissive to L. major growth than macrophages from MKP-2^+/+ mice, reflecting their reduced iNOS and increased Arginase-1 expression, LPS/IFN-γ activation was equally effective at controlling parasite growth in MKP-2^−/− and MKP-2^+/+ macrophages. Consequently, in the absence of any switch in the T_H1/T_H2 balance in MKP-2^−/− mice, no significant change in disease phenotype was observed.     

<Emphasis Type="Italic">Microbacterium rhizosphaerae</Emphasis> sp. nov., isolated from a Ginseng field,South Korea

A novel Gram-stain positive, aerobic, short rod-shaped, non-motile bacterium, designated strain CHO1^T, was isolated from rhizosphere soil from a ginseng agriculture field. Strain CHO1^T was observed to form yellow colonies on R2A agar medium. The cell wall peptidoglycan was found to contain alanine, glycine, glutamic acid, d-ornithine and serine. The cell wall sugars were identified as galactose, mannose, rhamnose and ribose. Strain CHO1^T was found to contain MK-11, MK-12, MK-13 as the predominant menaquinones and anteiso-C_15:0, iso-C_16:0, and anteiso-C_17:0 as the major fatty acids. Diphosphatidylglycerol, phosphatidylglycerol, phosphoglycolipid, an unidentified phospholipid and three unidentified glycolipids were found to be present in strain CHO1^T. Based on 16S rRNA gene sequence analysis, strain CHO1^T was found to be closely related to Microbacterium mangrovi DSM 28240^T (97.81 % similarity), Microbacterium immunditiarum JCM 14034^T (97.45 %), Microbacterium oryzae JCM 16837^T (97.33 %) and Microbacterium ulmi KCTC 19363^T (97.10 %) and to other species of the genus Microbacterium. The DNA G+C content of CHO1^T was determined to be 70.1 mol %. The DNA–DNA hybridization values of CHO1^T with M. mangrovi DSM 28240^T, M. immunditiarum JCM 14034^T, M. oryzae JCM 16837^T and M. ulmi KCTC 19363^T were 46.7 ± 2, 32.4 ± 2, 32.0 ± 2 and 29.2 ± 2 %, respectively. On the basis of genotypic, phenotypic and phylogenetic properties, it is concluded that strain CHO1^T represents a novel species within the genus Microbacterium, for which the name Microbacterium rhizosphaerae sp. nov. is proposed. The type strain of M. rhizosphaerae is CHO1^T (= KEMB 7306-513^T = JCM 31396^T).     

<Emphasis Type="Italic">Thauera sinica</Emphasis> sp. nov., a phenol derivative-degrading bacterium isolated from activated sludge

A bacterial strain, K11^T, capable of degrading phenol derivatives was isolated from activated sludge of a sewage treatment plant in China. This strain, which can degrade more than ten phenol derivatives, was identified as a Gram-stain negative, rod-shaped, asporogenous, facultative anaerobic bacterium with a polar flagellum. The strain was found to grow in tryptic soy broth in the presence of 0–2.5% (w/v) NaCl (optimum 0–1%), at 4–43 °C (optimum 30–35 °C) and pH 4.5–10.5 (optimum 7.5–8). Comparative analysis of nearly full-length 16S rRNA gene sequences showed that this strain belongs to the genus Thauera. The 16S rRNA gene sequence was found to show high similarity (97.5%) to that of Thauera chlorobenzoica 3CB-1^T, with lesser similarity to other recognised Thauera strains. The G+C content of the DNA of the strain was determined to be 67.8 mol%. The DNA–DNA hybridization value between K11^T and Thauera aromatica DSM6984^T was 10.4 ± 4.5%. The genomic OrthoANI values of K11^T with the other nine type strains of genus Thauera were less than 81.1%. Chemotaxonomic analysis of strain K11^T revealed that Q-8 is the predominant quinone; the polar lipids contain phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine, two unidentified phospholipids and five uncharacterised lipids; the major cellular fatty acid was identified as summed feature 3 (C_16:1 ω7c and/or iso-C_15:0 2-OH; 45.9%), followed by C_16:0 (20.5%) and C_18:1 ω7c (15.8%). Based on the phenotypic and phylogenetic evidence, DNA–DNA hybridisation, OrthoANI, chemotaxonomic analysis and results of the physiological and biochemical tests, a new species named Thauera sinica sp. nov. is proposed with strain K11^T (= CGMCC 1.15731^T = KACC 19216^T) designated as the type strain.     

Four new species of Chryseobacterium from the rhizosphere of coastal sand dune plants, Chryseobacterium elymi sp. nov., Chryseobacterium hagamense sp. nov., Chryseobacterium lathyri sp. nov. and Chryseobacterium rhizosphaerae sp. nov.

The taxonomic positions of five Gram-negative, non-spore-forming and non-motile bacterial strains isolated from the rhizosphere of sand dune plants were examined using a polyphasic approach. The analysis of the 16S rRNA gene sequence indicated that all of the isolates fell into four distinct phylogenetic clusters belonging to the genus Chryseobacterium of the family Flavobacteriaceae. The 16S rRNA gene sequence similarities of isolates to mostly related type strains of Chryseobacterium ranged from 97.5% to 98.5%. All strains contained MK-6 as the predominant menaquinone, and iso-C_15:0, iso-C_17:0 3-OH and a summed feature of iso-C_15:0 2-OH and/or C_16:1 ω7c as the dominant fatty acids. Combined phenotypic, genotypic and chemotaxonomic data supported that they represented four novel species in the genus Chryseobacterium, for which the names Chryseobacterium hagamense sp. nov. (type strain RHA2-9^T=KCTC 22545^T=NBRC 105253^T), Chryseobacterium elymi sp. nov. (type strain RHA3-1^T=KCTC 22547^T=NBRC 105251^T), Chryseobacterium lathyri sp. nov. (type strain RBA2-6^T=KCTC 22544^T=NBRC 105250^T), and Chryseobacterium rhizosphaerae sp. nov. (type strain RSB3-1^T=KCTC 22548^T=NBRC 105248^T) are proposed.     

Tepidanaerobacter acetatoxydans sp. nov., an anaerobic, syntrophic acetate-oxidizing bacterium isolated from two ammonium-enriched mesophilic methanogenic processes

Four anaerobic syntrophic acetate-oxidizing bacteria, the thermotolerant strains Re1^T, Re2, T1 and T2, were isolated from two different mesophilic methanogenic systems. The strains originate from sludge of a continuously stirred laboratory-scale reactor containing high levels of ammonium and from a high ammonium enrichment culture. Comparative 16S rRNA gene sequence analysis confirmed that the strains belong to the Firmicutes-Clostridia class. The most closely related species to strains Re1^T, Re2, T1 and T2 was Tepidanaerobacter syntrophicus, with a 16S rRNA gene sequence identity of 96%. The DNA-DNA relatedness of strains Re2, T1 and T2 to strain Re1^T was 92, 102, 81%, respectively. The gene encoding the acetogen key enzyme formyltetrahydrofolate synthetase (FTHFS) was detected and partly sequenced from the strains. In pure culture the bacteria used different organic compounds as carbon and energy source, such as organic acids, alcohols, sugars and amino acids. Furthermore, acetate-oxidizing ability was observed during co-cultivation with a hydrogen-consuming Methanoculleus sp. The bacteria were found to be spore-forming, rod-shaped and motile, and possessed Gram-positive cell walls. The four strains were thermotolerant and grew at temperatures between 25 and 55 °C. Strain Re1^T had a DNA G + C content of 38.4% and the major fatty acids were C_18:1 w7c, C_18:1 w9c, anteiso-C_17:0, C_16:1 w7c and C_18:0. The genetic and phenotypic properties of strains Re1^T, Re2, T1 and T2 suggest classification as representatives of a novel species of the genus Tepidanaerobacter; the name Tepidanaerobacter acetatoxydans sp. nov. is suggested. The type strain of T. acetatoxydans is Re1^T (=DSM 21804^T = JCM 16047^T).     

Caulobacter zeae sp. nov. and Caulobacter radicis sp. nov., novel endophytic bacteria isolated from maize root (Zea mays L.)

Four bacterial strains designated 410^T, 441, 695^T and 736 were isolated from maize root in Beijing, P. R. China. Based on 16S rRNA gene phylogeny, the four strains formed two clusters in the genus Caulobacter. Since strain 441 was a clonal variety of strain 410^T, only three strains were selected for further taxonomic studies. The whole genome average nucleotide identity (ANI) value between strains 410^T and 695^T was 94.65%, and both strains shared less than 92.10% ANI values with their close phylogenetic neighbors Caulobacter vibrioides DSM 9893^T, Caulobacter segnis ATCC 21756^T and Caulobacter flavus CGMCC 1.15093^T. Strains 410^T and 695^T contained Q-10 as the sole ubiquinone and their major fatty acids were C_{16:0, 11-methyl C18:1ω 0}, 11-methyl C_{18: 1}ω7c, summed feature 3 (C_{16:1ω7c and/or C16:1ω 1}ω7c and/or C_{16: 1}ω6c) and summed feature 8 (C_{18:1ω7c and/or C18:1ω 1}ω7c and/or C_{18: 1}ω6c). Their major polar lipids consisted of glycolipids and phosphatidylglycerol, and phenotypic tests differentiated them from their closest phylogenetic neighbors. Based on the results obtained, it is proposed that the three strains represent two novel species, for which the names Caulobacter zeae sp. nov. (type strain 410^T = CGMCC 1.15991 = DSM 104304) and Caulobacter radicis sp. nov. (type strain 695^T = CGMCC 1.16556 = DSM 106792) are proposed.