Nocardia heshunensis sp. nov., an actinomycete isolated from soil.

A novel Gram-stain-positive, aerobic, non-motile and acid-fast actinomycete strain, designated CFH S0067T, was isolated from a soil sample collected from Heshun old town in Tengchong, Yunnan province, in south-west PR China. The taxonomic position of strain CFH S0067T was studied in detail using a polyphasic approach. Phylogenetic analysis, based on 16S rRNA gene sequences, revealed that strain CFH S0067T belongs to the genus Nocardia and is closely related to Nocardia concava JCM 12351T (99.3 % similarity), forming a separated branch with this type strain. However, the strain shared 96.0 % gyrB gene sequence similarity with N. concava JCM 12351T. Furthermore, DNA-DNA hybridization showed 56.5±0.6 % DNA relatedness between the novel strain and N. concava JCM 12351T. The whole-cell hydrolysates contained meso-diaminopimelic acid (type IV) and arabinose, galactose, fructose and mannose. The major polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol, phosphatidylinositol mannoside and one unidentified lipid. Strain CFH S0067T contained MK-8 (H4ω-cycl) as the predominant menaquinone. C16 : 0, summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c), C18 : 1ω9c and C18 : 0 10-methyl (TBSA) were the major cellular fatty acids. Mycolic acids were also detected. The G+C content of the genomic DNA was determined to be 66.9 mol%. A combination of the low DNA-DNA hybridization values and phenotypic properties demonstrated that strain CFH S0067Tis clearly distinguishable from its most closely related strain, N. concava JCM 12351T. On the basis of this polyphasic study, it is concluded that strain CFH S0067T should be considered to represent a novel species of the genus Nocardia, for which the name Nocardia heshunensis sp. nov. is proposed. The type strain is CFH S0067T (=DSM 46764T=JCM 30085T).

Nocardia tengchongensis sp. nov., isolated from a soil sample.

The taxonomic status was determined of two actinomycetes, designated CFH S0057T and CFH S0065, that were isolated from soil samples collected from an extinct volcano in Tengchong county, Yunnan province, south-west China. Phylogenetic analysis based on 16S rRNA gene sequences showed that strains CFH S0057T and CFH S0065 belong to the genus Nocardia and formed a single clade within this genus. The two isolates were able to grow at 4-45 °C, pH 5.0-7.0 and with a NaCl tolerance up to 5.0% (w/v). The whole-cell hydrolysates were rich in meso-diaminopimelic acid, galactose, arabinose and fructose. Mycolic acids were present. Strains CFH S0057T and CFH S0065 exhibited a menaquinone system with MK-8 (H4, ω cyclo), and the major polar lipids consisted of diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol, phosphatidylinositol mannoside and one unidentified phospholipid. Major fatty acids were C16:0, Summed features 3, C18:1 ω9c and C18:0 10-methyl (TBSA). The genomic DNA G + C contents of strains CFH S0057T and CFH S0065 were 65.7 and 66.1 mol%, respectively. The combined genotypic, phenotypic and chemotaxonomic results indicated the isolates are considered to represent a novel species of the genus Nocardia, for which the name Nocardia tengchongensis sp. nov. is proposed. The type strain is CFH S0057T (= KCTC 29485T = JCM 30083T).

Crenalkalicoccus roseus gen. nov., sp. nov., a thermophilic bacterium isolated from alkaline hot springs.

Two closely related thermophilic bacterial strains, designated YIM 78023T and YIM 78058, were isolated from samples collected from two alkaline hot springs in Tengchong county, Yunnan province, south-west China. The novel isolates were Gram-stain-negative, non-motile, aerobic ovoid- to coccoid-shaped and non-spore-forming. Strain YIM 78023T grew at 20-60 ºC and pH 6.0-9.0 with optimal growth observed at 40-50 ºC and pH 8.0, while strain YIM 78058 grew at 25-60 ºC and pH 6.0-10.0 with optimal growth at 45-50 ºC and pH 8.0. Phylogenetic analysis based on 16S rRNA gene sequences affiliated these two isolates within the family Acetobacteraceae with high sequence similarities to members of the genera Roseomonas and Belnapia (all sequence similarities <94.5 %). In addition to the above two genera, these strains also clustered with the genera Craurococcus and Paracraurococcus (having sequence similarities <93.3 %) in the phylogenetic tree, but with a distinct lineage within the family Acetobacteraceae. The major ubiquinone was Q-10 and the major fatty acids observed were C18:1ω7c, summed feature 4 and C16:0. The genomic DNA G+C contents observed for strains YIM 78023T and YIM 78058 were 74.3 and 74.0 mol%, respectively. Morphological, phylogenetic and chemotaxonomic results suggest that strains YIM 78023T and YIM 78058 are representatives of a novel species of a new genus within the family Acetobacteraceae, for which the name Crenalkalicoccus roseus gen. nov., sp. nov. is proposed. The type strain of Crenalkalicoccus roseus is YIM 78023T (=JCM 19657T=KACC 17825T).

Sinomonas halotolerans sp. nov., an actinobacterium isolated from a soil sample.

A novel actinobacterial strain, designated CFH S0499(T), was isolated from a soil sample collected from Catba island in Halong Bay, Vietnam. The cells were observed to be Gram-stain positive, aerobic, non-motile, curved rods. The strain was found to grow optimally at 28 °C and pH 7.0. Growth was found to occur at 0-7 % NaCl. Chemotaxonomically, the peptidoglycan type was determined to be of the A3α type, with glutamic acid, glycine, alanine and lysine as the major cell wall amino acids. The whole cell sugars were found to contain mannose, galactose, glucose, ribose and rhamnose. The polar lipids were identified as diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol, glycolipids and two unidentified phospholipids. The major fatty acids were identified as anteiso-C15:0, iso-C15:0, anteiso-C17:0 and iso-C16:0 and the predominant respiratory quinone as MK-9 (H2), with a minor amount of MK-10 (H4) and MK-8 (H2). The G+C content of the genomic DNA was determined to be 71.8 mol%. The 16S rRNA gene sequence analysis showed that strain CFH S0499(T) should be assigned to the genus Sinomonas and is closely related to members of the species Sinomonas atrocyanea DSM 20127(T) (98.3 %), Sinomonas soli CW 59(T) (98.28 %), Sinomonas flava CW 108(T) (98.26 %), Sinomonas mesophila MPLK 26(T) (97.5 %) and Sinomonas notoginsengisoli SYP-B 575(T) (95.8 %). DNA-DNA hybridizations showed low values (49.1-54.5 %) between strain CFH S0499(T) and its four closest neighbours. Based on phenotypic, chemotaxonomic and phylogenetic analysis, strain CFH S0499(T) is concluded to represent a novel species of the genus Sinomonas, for which the name Sinomonas halotolerans sp. nov. is proposed, with CFH S0499(T) as the type strain (=CCTCC AB2014300(T) = KCTC 39116(T)).

Meiothermus roseus sp. nov., a thermophilic bacterium isolated from a geothermal area.

Two closely related thermophilic bacterial strains, designated YIM 71031(T) and YIM 71039, were isolated from a hot spring in Tengchong county, Yunnan province, south-western China. The novel isolates were observed to be Gram-negative, aerobic, rod-shaped and yellow-pigmented bacteria. The strains were found to be able to grow at 37-65 °C, pH 6.0-9.0 and with a NaCl tolerance up to 1.0 % (w/v). Phylogenetic analysis based on 16S rRNA gene sequences placed these two isolates in the genus Meiothermus. They were found to be closely related to Meiothermus timidus DSM 17022(T) (98.6 % similarity), and formed a cluster with this species. The predominant menaquinone was identified as MK-8 and the major fatty acids (>10 %) as anteiso-C15:0, iso-C15:0, anteiso-C17:0, iso-C16:0 and C16:0. The genomic DNA G+C contents of strains YIM 71031(T) and YIM 71039 were determined to be 64.0 and 65.4 mol%, respectively. DNA-DNA hybridizations showed low values between strains YIM 71031(T) and YIM 71039 and their closely related neighbour M. timidus DSM 17022(T). Morphological phylogenetic and chemotaxonomic results suggest that strains YIM 71031(T) and YIM 71039 are representatives of a new species within the genus Meiothermus, for which the name Meiothermus roseus sp. nov. is proposed. The type strain is YIM 71031(T) (=KCTC 42495(T) =NBRC 110900(T)).

Cecembia rubra sp. nov., a thermophilic bacterium isolated from a hot spring sediment.

A Gram-staining negative, rod-shaped bacterium, designated strain YIM 78110(T), was isolated from a sediment sample collected from Hehua hot spring in Tengchong, Yunnan province, south-west China. The taxonomic status of strain YIM 78110(T) was confirmed by a polyphasic approach. 16S rRNA gene sequence analysis indicated that strain YIM 78110(T) belongs to the genus Cecembia, displaying 96.8% and 94.7% sequence similarity with the two most closely related type strains, Cecembia calidifontis RQ-33(T) and Cecembia lonarensis LW9T, respectively. The low value of DNA-DNA hybridization (52.3 ± 2.3%) between strain YIM 78110(T) and its closest neighbour, Cecembia calidifontis RQ-33(T), indicated that this new isolate represented a different genomic species in the genus Cecembia. The temperature for growth ranged from 30 to 50 °C. The pH for growth ranged from pH 4.0 to 10.0, with NaCl tolerance of 0.5-6.0% (w/v). The predominant menaquinone of strain YIM 78110(T) was MK-7 and the major polar lipid was phosphatidylethanolamine. The major fatty acids were iso-C15:0 and C15:0. The DNA G+C content was 47.1 mol%. On the basis of physiological, biochemical and phylogenetic analyses, it is proposed that strain YIM 78110(T) represents a novel species of the genus Cecembia, for which the name Cecembia rubra sp. nov. is proposed. The type strain is YIM 78110(T) ( = CCTCC AB2013287(T) = DSM 28057(T)).

Rhodococcus agglutinans sp. nov., an actinobacterium isolated from a soil sample.

A Gram-positive, aerobic, non-motile and non-spore forming strain, designated CFH S0262(T), was isolated from a soil sample collected from Catba island in Halong Bay, Vietnam. A polyphasic approach was used to study the taxonomic position of this new isolate. Phylogenetic analyses based on 16S rRNA gene sequence showed that strain CFH S0262(T) belongs to the genus Rhodococcus and clustered with Rhodococcus soli DSD51W(T), Rhodococcus hoagii NBRC 103062(T), Rhodococcus defluvii Call(T) and Rhodococcus kunmingensis YIM 45607(T) (98.7, 98.5, 97.9 and 97.6% similarities, respectively). Strain CFH S0262(T) could grow in the presence of NaCl (0-4%, optimum 0-3%), at pH 6.0-8.0 (optimum, pH 7.0) and at 10-40 °C (optimum, 28 °C). The predominant menaquinones of strain CFH S0262(T) were identified as MK-8 (H2) and MK-8 (H4). The major fatty acids (≥10%) were found to be C(16:0) and C(18:1)ω9c. The polar lipids detected were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol, phosphatidylinositol mannoside, a glycolipid and two unidentified phospholipids. The DNA G+C content was determined to be 71.4 mol%. Based on a comparative analysis of phenotypic and genotypic characteristics, in combination with low values of DNA-DNA hybridization between strain CFH S0262(T) and its closest neighbours, it is proposed that strain CFH S0262(T) represents a novel species of the genus Rhodococcus, for which the name Rhodococcus agglutinans sp. nov., is proposed, with the type strain CFH S0262(T) (=CCTCC AB2014297(T)=KCTC 39118(T)).

Identification and functional characterization of the human ether-a-go-go-related gene Q738X mutant associated with hereditary long QT syndrome type 2.

QT interval prolongation, a risk factor for arrhythmias, may be associated with genetic variants in genes governing cardiac repolarization. Long QT syndrome type 2 (LQT2) is caused by mutations in the human ether-a-go­go-related gene (hERG). This gene encodes a voltage-gated potassium channel comprised of 4 subunits, and the formation of functional channels requires the proper assembly of these 4 subunits. In the present study, we investigated the role of the LQT2 mutation, Q738X, which causes truncation of the C-terminus of hERG channels, in the assembly and function of hERG channels. When expressed in HEK293 cells, Q738X did not generate an hERG current. The co-expression of Q738X with wild-type (WT)-hERG did not cause the dominant-negative suppression of the WT-hERG current. Western blot analysis and confocal microscopy revealed that the Q738X mutation caused defective trafficking of hERG channel proteins. Co-immunoprecipitation demonstrated that Q738X did not exhibit dominant-negative effects due to the failure of the mutant and WT subunits to co-assemble. In conclusion, the functional loss caused by the Q738X mutation in hERG K+ channels may be attributed to the disruption of tetrameric assembly.

Streptomyces calidiresistens sp. nov., isolated from a hot spring sediment.

A Streptomyces-like actinomycete strain, designated as YIM 78087(T), was isolated from a sediment sample collected from Hehua hot spring in Tengchong, Yunnan province, south-west China. The taxonomic position of strain YIM 78087(T) was investigated by a polyphasic approach. Phylogenetic analyses based on 16S rRNA gene sequences showed that strain YIM 78087(T) belongs to the genus Streptomyces and is closely related to Streptomyces fimbriatus DSM 40942(T), Streptomyces marinus DSM 41968(T) and Streptomyces qinglanensis DSM 42035(T) (97.18, 97.05 and 97.1 % similarity, respectively). Combined with the low values of DNA-DNA hybridization between strain YIM 78087(T) and its closest neighbours, these analyses indicated that this new isolate represents a different genomic species in the genus Streptomyces. The predominant menaquinones of strain YIM 78087(T) were identified as MK-9 (H4) and MK-9 (H6). The major fatty acids were identified as anteiso-C15:0 (28.4 %), anteiso-C17:0 (23.0 %) and iso-C16:0 (15.1 %). The whole-cell hydrolysates found to contain glucose, mannose and ribose. The DNA G+C content was determined to be 73.0 mol%. Based on the comparative analysis of phenotypic and genotypic characteristics, it is proposed that strain YIM 78087(T) represents a novel species of the genus Streptomyces, for which the name Streptomyces calidiresistens sp. nov., is proposed. The type strain is YIM 78087(T) (=BCRC 16955(T)=DSM 42108(T)=JCM 19629(T)).

Roseomonas alkaliterrae sp. nov., isolated from an alkali geothermal soil sample in Tengchong, Yunnan, South-West China.

An alkalitolerant, thermotolerant and Gram-stain negative bacterium, designated strain YIM 78007(T), was isolated from an alkaline geothermal soil sample from Hehua hot spring, Tengchong, Yunnan province, south-west China. Cells of strain YIM 78007(T) were observed to be aerobic and short rod-shaped. The colonies were observed to be orange-red, convex and circular. 16S rRNA gene sequence-based phylogenetic analysis showed that strain YIM 78007(T) clustered with members of the genus Roseomonas (with similarities from 97.2 to 92.2 %). Optimal growth of strain YIM 78007 occurs at 40-50 °C and pH 8.0-10.0. The predominant ubiquinone was identified as Q-10 and the major fatty acids were identified as C18:1 ω7c and C16:0. The polar lipids were identified as diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine, two unidentified aminolipids and one unknown phospholipid. The G + C content of the genomic DNA was determined to be 63 mol %. The levels of DNA-DNA hybridization relatedness between strain YIM 78007(T) and its closet neighbours (Roseomonas lacus JCM 13283(T) and Roseomonas terrae JCM 14592(T)) were well below the threshold required for the proposal of a novel species. The results of physiological and biochemical characteristics, the phylogenetic analysis, as well as low DNA-DNA hybridization values, allowed the phenotypic and genotypic differentiation of strain YIM 78007(T) from its closest phylogenetic neighbours. Therefore, strain YIM 78007(T) is considered to represent a novel species of the genus Roseomonas, for which the name Roseomonas alkaliterrae sp. nov. is proposed. The type strain is YIM 78007(T) (=BCRC 80644(T) = JCM 19656(T)).

Zhizhongheella caldifontis gen. nov., sp. nov., a novel member of the family Comamonadaceae.

An alkalitolerant, thermotolerant, strictly aerobic and Gram-staining negative bacterial strain, designated YIM 78140(T), was isolated from a water sample in Hehua hot spring, Tengchong, Yunnan province, south-west China. The colonies were light brown, convex and circular. Phylogenetic analysis of the 16S rRNA gene sequence of strain YIM 78140(T) indicated that it was clustered with members of ß-Proteobacteria (with the similarity from 96.9 to 93.6 %). Good growth occurred at 40-50 °C, pH 8.0-9.0 and in the presence of 0-3 % (w/v) NaCl. The predominant ubiquinones were Q-8 and Q-9. The major fatty acids were C16:0, C17:0 cyclo, C18:1 ω7c and summed feature 3. The G+C content of genomic DNA was 70.8 mol%. The results of physiological and biochemical characteristics, phylogenetic analysis allowed the phenotypic and genotypic differentiation of strain YIM 78140(T) from its closest phylogenetic neighbours. Therefore, the strain YIM 78140(T) represents a novel genus of the family Comamonadaceae, for which the name Zhizhongheella caldifontis gen. nov., sp. nov. is proposed. The type strain is YIM 78140(T) (= BCRC 80649(T) = KCTC 32557(T)).

Blockage of hERG current and the disruption of trafficking as induced by roxithromycin.

Roxithromycin is an oral macrolide antibiotic agent that has been repeatedly reported to provoke excessive prolongation of the Q-T interval and torsades de pointes in clinical settings. To investigate the mechanisms underlying the arrhythmogenic side effects of roxithromycin, we studied the molecular mechanisms of roxithromycin on human ether-à-go-go-related gene (hERG) K(+) channels expressed in human embryonic kidney (HEK293) cells. Roxithromycin was found to inhibit wild-type (WT) hERG currents in a concentration-dependent manner with a half-maximum block concentration (IC50) of 55.8 ± 9.1 µmol/L. S6 residue hERG mutants (Y652A and F656C) showed reduced levels of hERG current blockage attributable to roxithromycin. Roxithromycin also inhibited the trafficking of hERG protein to the cell membrane, as confirmed by Western blot analysis and confocal microscopy. These findings indicate that roxithromycin may cause acquired long-QT syndrome via direct inhibition of hERG current and by disruption of hERG protein trafficking. Mutations in drug-binding sites (Y652A or F656C) of the hERG channel were found to attenuate hERG current blockage by roxithromycin, but did not significantly alter the disruption of trafficking.

[Evaluation of the shaping ability of four Ni-Ti rotary instruments in the preparation of simulated curved root canals].

PURPOSE: To evaluate the effect of four Ni-Ti rotary instruments on the preparation of L-shaped resin root canals. METHODS: 40 L-shaped resin root canals (curvature=38.5°) were divided randomly into four groups: Hero642,Protaper, K3 and Mtwo. Resin root canals were prepared according to the protocols. Preparation time was recorded. Original and postoperative canal images were scanned and superimposed. The preparation effect was evaluated by computer software, such as resin removal amount in inner and outer wall of root canals, change of curvature degree and radius, etc. The data was analyzed with SPSS13.0 software package. RESULTS: The preparing time of K3 was the longest. Mtwo was the shortest(P<0.05). Resin removal amount showed significant difference among the four instruments in inner root canal wall at BC, O and HO as well as in outer root canal wall at AC, HO and O. Protaper achieved the largest tapered canal,but was the worst for centering ability in the bend. Apical transportation increased near to apical foramen. The four Ni-Ti rotary instruments showed no significant difference regarding safety, undesirable shape, change of root canal's curvature degree and radius except two instrument fracture cases (K3 and Protaper) and two step cases(K3). Postoperative working length tended to be shorter,and root canals were straightened. CONCLUSIONS: Mtwo prepares simulated resin curved root canals fast. Postoperative root canal's taper by Protaper is significantly larger than Hero642. The 4 Ni-Ti rotary instruments perform good cutting ability and keep root canal's original curvature well.