Kitasatospora cathayae sp. nov., a novel endophytic actinomycete isolated from the leaves of Cathaya argyrophylla.

Strain HUAS 3-15T was isolated from the leaves of Cathaya argyrophylla collected from Chenzhou, Hunan Province, PR China. The main fatty acids (>5.0 %) of the strain were anteiso-C15 : 0, C16 : 0, C18 : 1 ω9c, iso-C16 : 0, summed feature 5 (C18 : 2 ω6,9c/C18 : 0 ante), iso-C15 : 0 and anteiso-C17 : 0. MK-9(H6), MK-9(H8) and MK-9(H4) were detected as respiratory quinones. The diagnostic cell-wall diamino acid was meso-diaminopimelic acid. Galactose, glucose and ribose were also present in the cell wall. The major polar lipids consisted of diphosphatidylglycerol, phosphatidyl ethanolamine, phosphatidylinositol mannosides and unidentified phospholipids. The DNA G+C content of the genome sequence, consisting of 8 860 963 bp, is 72.4 mol%. blast analysis based on 16S rRNA gene sequences revealed that the strain belongs to the genus Kitasatospora, with 99.37, 99.03, 98.95, 98.68 and 98.67 % sequence similarity to Kitasatospora aureofaciens ATCC 10762T, Kitasatospora viridis DSM 44826T, Kitasatospora xanthocidica NBRC 13469T, Kitasatospora aburaviensis NRRL B-2218T and Kitasatospora kifunensis IFO 15206T, respectively. Phylogenetic trees based on 16S rRNA gene and whole-genome sequences demonstrated that strain HUAS 3-15T formed a well-supported cluster with K. aureofaciens ATCC 10762T. Further genomic characterization through average nucleotide identity (ANIb/m) and digital DNA-DNA hybridization analysis between strain HUAS 3-15T and K. aureofaciens ATCC 10762T showed values of 90.62/92.55 % and 45.3 %, respectively, lower than the 95-96 % ANI threshold and 70.0 % cutoff used as guideline values for species delineation in bacteria. Furthermore, the differences between the strain and its phylogenomic neighbour in terms of physiological (e.g. sole carbon source growth) and chemotaxonomic (e.g. cellular fatty composition) characteristics further supported this conclusion. Consequently, we concluded that strain HUAS 3-15T represents a novel species of the genus Kitasatospora, for which the name Kitasatospora cathayae sp. nov. is proposed. The type strain is HUAS 3-15T (=MCCC 1K08542T=JCM 36274T).

Streptomyces chengbuensis sp. nov., isolated from the rhizosphere soil of Cathaya argyrophylla.

Strain HUAS CB01T was a novel actinobacterium which was isolated from the rhizosphere soil of Cathaya argyrophylla, Chengbu Miao Autonomous County of Hunan Province, China. The strain formed well-growing substrate mycelium, diffusible pigments, and aerial mycelium, and differentiated into spiral-type spore chains composed of smooth-surface rod-shaped spores. Phylogenetic analysis on account of 16 S rRNA gene sequence demonstrated the strain HUAS CB01T was a member of the genus Streptomyces and had a close relationship with Streptomyces wuyuanensis CGMCC 4.7042 T (100%) and Streptomyces marianii ICN19T (99.86%). Genome-based comparisons indicated that strain HUAS CB01T could be distinctly different from its closest species, Streptomyces wuyuanensis CGMCC 4.7042 T, Streptomyces marianii ICN19T, with ANIm and dDDH results of 92.78% and 45.90%, 92.22% and 43.30%, respectively, far less than 96.7 and 70% cut-off points recommended for delineating species. The main cellular fatty acids concluded anteiso-C15:0, iso-C14:0, iso-C16:0, C16:0 and C16:1 2OH. The menaquinones were MK-9(H4), MK-9(H6) and MK-9(H8) and the whole-cell sugars consisted of ribose and mannose. The polar lipids included phosphatidyl ethanolamine, diphosphatidylglycerol, phosphatidylglycerol, mannosides and unidentified phospholipids. According to these genotypic and phenotypic characteristics, strain HUAS CB01T can be distinguished and representative to be a novel species of the genus Streptomyces, for which the name Streptomyces chengbuensis is proposed. The type strain is HUAS CB01T ( = MCCC 1K08666T = JCM 36277 T).

New insights into the relationship between the average nucleotide identity and the digital DNA-DNA hybridization values in the genus Amycolatopsis and Amycolatopsis cynarae sp. nov., a novel actinobacterium from the rhizosphere soil of Cynara scolymus, and proposal of Amycolatopsis niigatensis as a synonym of Amycolatopsis echigonensis based on comparative genomic analysis.

At present, it is widely believed that a 95-96% average nucleotide identity (ANI) value is equivalent to a 70% digital DNA-DNA hybridization (dDDH) value in the prokaryotic taxonomy. However, in the present study, comparative genome analysis of 29 pairs of Amycolatopsis type strains revealed that a 70% dDDH value did not correspond to a 95-96% ANI based on the MuMmer ultra-rapid aligning tool (ANIm) but approximately corresponded to a 96.6% ANIm value in the genus Amycolatopsis. Based on this corresponding relationship, phenotypic and chemotaxonomical characteristics, as well as phylogenetic analysis, an actinobacterial strain HUAS 11-8T isolated from the rhizosphere soil of Cynara scolymus, was subjected to a polyphasic taxonomic characterization. Based on EzBioCloud alignment, it was found that strain HUAS11-8T had the 16S rRNA gene similarities of 99.78% with A. rhizosphaerae JCM 32589T, 97.8% with A. dongchuanensis YIM 75904T, and < 97.8% sequence similarities to other Amycolatopsis species. Phylogenetic analysis of 16S rRNA gene sequences and whole-genome sequences revealed that strain HUAS 11-8T was closely related to A. rhizosphaerae JCM 32589T. ANIm and dDDH values between strains HUAS 11-8T and A. rhizosphaerae JCM 32589T were 96.3 and 68.5%, respectively, lower than the 96.6 and 70% thresholds recommended for the delineation of a novel Amycolatopsis species. Consequently, strain HUAS 11-8T should represent a novel Amycolatopsis species, for which the name Amycolatopsis cynarae sp. nov. (type strain HUAS 11-8T = MCCC 1K08337T = JCM 35980T) is proposed. Furthermore, based on comparative genomic analysis and rule 42 of the Prokaryotic Code, we propose that Amycolatopsis niigatensis is a later heterotypic synonym of Amycolatopsis echigonensis.

Proposal of Streptomyces bellus Margalith and Beretta 1960 as a Later Heterotypic Synonym of Streptomyces coeruleorubidus (Preobrazhenskaya 1957) Pridham et al. 1958 and an Emended Description of Streptomyces coeruleorubidus.

In the present work, the taxonomic relationship between Streptomyces coeruleorubidus and Streptomyces bellus was reevaluated by a comprehensive comparison of phenotypic, chemotaxonomic and genomic characteristics, as well as phylogeny. In 1957 and 1960, Streptomyces coeruleorubidus and Streptomyces bellus were described as two novel Streptomyces species. The full-length 16S rRNA gene sequence analysis indicated that Streptomyces bellus JCM 4292T shared highest sequence identity with Streptomyces coerulescens ISP 5146T (100%). Phylogenetic analysis of 16S rRNA gene sequence showed that S. bellus JCM 4292T was most closely related to Streptomyces coerulescens ISP 5146T. Phylogenetic analysis of five housekeeping gene sequences demonstrated that S. bellus JCM 4292T was most closely related to S. coeruleorubidus ATCC 13740T. Nevertheless, the ANIm (average nucleotide identity based on MuMmer ultra-rapid aligning tool) and dDDH (digital DNA-DNA hybridization) values between them were 97.71% and 81.9%, respectively, greater than the threshold of 96.7% and 70% for the delineation of Streptomyces species, suggesting that they represent the same genomic species. In addition, phenotypic and chemotaxonomic characteristics, as well as phylogeny and genomic DNA-DNA correlation analysis also confirmed the above conclusion. Consequently, we proposed that S. bellus Margalith and Beretta 1960 is a later heterotypic synonym of S. coeruleorubidus (Preobrazhenskaya 1957) Pridham et al. 1958.

Outcomes of single-procedure radiofrequency catheter ablation for idiopathic ventricular arrhythmias: a single-centre retrospective cohort study.

OBJECTIVES: Radiofrequency catheter ablation is the first-line treatment for idiopathic premature ventricular complexes (PVCs) and ventricular tachycardias (VTs). However, the outcomes were less compared among the categories. The study aims to assess the effectiveness and safety of catheter ablation for idiopathic PVC/VTs in a single high-volume centre, using the right ventricular outflow tract (RVOT) as a reference. DESIGN: Retrospective cohort study. SETTING: Patient data were collected from a tertiary hospital in Guizhou, China. PARTICIPANTS: Between September 2013 and September 2022, 1028 patients (male: 41.3%; age: 46.5±15.6 years) who underwent the first catheter ablation for idiopathic monomorphic PVC/VTs were enrolled. OUTCOME MEASURES: Acute success, procedure-related complications, and long-term recurrence were assessed. Antiarrhythmic drugs (AADs) were not administrated after procedures unless recurrence was identified. RESULTS: The overall acute success rate was 90.3%, with 368 patients (35.8%) experiencing left ventricular PVC/VTs. No cases of third-degree atrioventricular block or death were reported. Complications were more common in patients with left ventricular PVC/VTs than those with right-sided ones (4.6% vs 0.1%, p<0.001). A total of 926 patients (90.1%) were followed up for an average of 9.7±3.7 months, and only the PVC/VTs category was found to be associated with long-term success rates. The RVOT, endocardial left ventricular outflow tract (endoLVOT), tricuspid annulus (TA) free wall, posterior septum and fascicular VT had long-term success rates exceeding 85%. Other types of PVC/VTs showed significantly higher risks of recurrence. CONCLUSIONS: Besides RVOT and fascicular VT, single-procedure catheter ablation without AADs is highly effective for endoLVOT, TA-free wall and posterior septum. Patients with left ventricular PVC/VTs have higher complication risks compared with right ones.

Investigating Origins of Ventricular Arrhythmia Arising From Right Ventricular Outflow Tract and Comparing Initial Ablation Strategies.

Background: The origin distribution in right ventricular outflow tract (RVOT) ventricular arrhythmias (VAs), as well as the initial ablation effectiveness of reversed U-curve method and antegrade method, remains unclear. Objectives: To investigate the origin distribution of RVOT-type VAs and compare the initial ablation effectiveness of the two methods. Method: Consecutive patients who had idiopathic RVOT-type VAs were prospectively enrolled. After activation mapping, patients were randomly assigned to supravalvular strategy using the reversed U-curve or subvalvular strategy using the antegrade method. The primary outcome was initial ablation (IA) success, defined as the successful ablation within the first three attempts. Results: Sixty-one patients were enrolled from November 2018 to June 2020. Activation mapping revealed that 34/61 (55.7%) of the earliest ventricular activating (EVA) sites were above the pulmonary valves (PVs). The IA success rate was 25/33 (75.8%) in the patients assigned to supravalvular strategy as compared with 16/28 (57.1%) in those assigned to subvalvular strategy (p = 0.172). Multivariate analysis revealed a substantial and qualitative interaction between the EVA sites and IA strategies (p interaction < 0.001). Either strategy had a remarkably higher IA success rate in treating its ipsilateral EVA sites than contralateral ones (p < 0.0083). Conclusion: Of the idiopathic RVOT-type VA origins, half were located above the PV. The supravalvular and subvalvular strategies did not differ in IA success rates. However, they were complementary to reveal the EVA sites and facilitate ipsilateral ablation, which produces a significantly higher IA success rate. Clinical Trial Registration: Chinese Clinical Trial Registry number, https://www.chictr.org.cn/showproj.aspx?proj=45623, ChiCTR2000029331.

Atrial average conduction velocity in patients with and without paroxysmal atrial fibrillation.

OBJECTIVES: To evaluate intra-atrial conduction delay in patients with atrial fibrillation (AF) via calculation of conduction velocities (CVs) of the right and left atria. METHODS: Electroanatomic mapping was performed during sinus rhythm, in the right atrium (RA) in eight patients with paroxysmal AF, in 12 controls with atrioventricular nodal re-entrant tachycardia (AVNRT) and in the left atrium (LA) in additional 16 AF patients. Three-dimensional maps of activation sequences of the RA and LA were obtained. Local CVs were specifically calculated in the direction of wave-front propagation on the activation maps by using 3-dimensional coordinates and local activation times of triads of sites. Average CVs of each atrium and each of 8 predefined RA and LA regions were calculated. RESULTS: During sinus rhythm, the average CVs of the RA were significantly slower (P<0·05) in the AF group (0·60 ± 0·12 m s-1 ) than in the controls (0·83 ± 0·13 m s-1 ). The average CVs of the RA basal, septal and annulus regions were significantly slower than the corresponding regions in controls (P<0·05). In patients with AF, the average CV of the LA was 0·51 ± 0·11 m s-1 , which is significantly slower than that of the RA and than that of LA as previously reported (P<0·05). CONCLUSION: Compared to patients with AVNRT, patients with AF are associated with conduction delay in both atria with the delay being more marked in the LA than in the RA, which suggests the involvement of conduction disturbances in the genesis and/or perpetuation of AF.

Coronary sinus draining into the left subclavian vein through a persistent left superior vena cava.

A persistent left superior vena cava (PLSVC) is formed by the remains of the oblique vein of the left atrium, which is not completely degenerated during embryonic development. The incidence is approximately 0.3% in the general population. Approximately 80-92% of PLSVCs drain into the right atrium through the coronary sinus. This report describes a rare case of PLSVC in which the coronary sinus (CS) did not open into the right atrium, but rather drained into the left subclavian vein through the PLSVC.

[Development of multi-channels cardiac electrophysiological polygraph with LabVIEW as software platform and its clinical application].

Polygraph has become a necessary instrument in interventional cardiology and fundamental research of medicine up to the present. In this study, a LabView development system (DS) (developed by NI in U.S.) used as software platform, a DAQ data acquisition module and universal computer used as hardware platform, were creatively coupled with our self-made low noise multi-channels preamplifier to develop Multi-channels electrocardiograph. The device possessed the functions such as real time display of physiological process, digit highpass and lowpass, 50Hz filtered and gain adjustment, instant storing, random playback and printing, and process control stimulation. Besides, it was small-sized, economically practical and easy to operate. It could advance the spread of cardiac intervention treatment in hospitals.

[Development and research of temporary demand pacemaker with electrocardiosignal display].

A temporary demand pacemaker with electrocardiosignal display is introduced in this paper. Double way low-noise electrocardiosignal preamplifier, amplitude limiter, high and low pass filter, 50 Hz notch filter, TTL level generator and stimulating pulse formation circuit are components of the hardware electrocircuit. The demand pacing and the electrocardiosignal display are separately controlled by the software in which the double microcontrollers communications technique is used. In this study, liquid crystal display is firstly used in body surface electrocardiosignal display or intracardial electrophysiologic signal display when the temporary demand pacemaker is installed and put into use. The machine has proven clinically useful and can be of wide appliation.