ABSTRACT
BACKGROUND: Compassion fatigue in nursing interns contributes to career indecision and worsens the nursing shortage. While work environment and psychological factors are well-studied, the ethical dimension remains unexplored. Understanding these mechanisms, particularly the role of moral courage, is essential for designing interventions to combat compassion fatigue and address the workforce crisis. This study investigates the influence of moral courage on compassion fatigue among Chinese nursing interns, focusing on the mediating roles of moral sensitivity and professional identity. METHODS: A quantitative, cross-sectional study was conducted in accordance with the STROBE guidelines. We used the convenience sampling method to recruit 467 nursing interns from four public junior colleges in Hunan Province, China in February, 2024. Data were collected using Compassion Fatigue Short Scale, Moral Courage Scale, Revised Moral Sensitivity Questionnaire, and Professional Identity Scale. Data analyses were conducted using SPSS 22.0 and Amos 21.0. RESULTS: The modified model exhibited a good fit (χ2/df = 3.437, AGFI = 0.928, IFI = 0.984, TLI = 0.976, CFI = 0.984, NFI = 0.977, RMSEA = 0.072). Moral sensitivity positively influenced both moral courage and professional identity, while professional identity negatively impacted compassion fatigue. Importantly, the effect of moral courage on compassion fatigue was entirely mediated by moral sensitivity and professional identity (ß = -0.114, P = 0.001). CONCLUSION: This study suggests that moral courage in nursing interns mitigates compassion fatigue through the combined mediating effects of moral sensitivity and professional identity. Ethics education programs fostering moral courage, moral sensitivity, and professional values in nursing students could be crucial in alleviating compassion fatigue.
ABSTRACT
Water electrolysis has become an attractive hydrogen production method. Oxygen evolution reaction (OER) is a bottleneck of water splitting as its four-electron transfer procedure presents sluggish reaction kinetics. Designing composite catalysts with high performance for efficient OER still remains a huge challenge. Here, the P-doped cobalt oxide/NiFe layered double hydroxides (P-CoOX/NiFe LDHs) composite catalysts with amorphous/crystalline interfaces are successfully prepared for OER by hydrothermal-electrodeposition combined method. The results of electrochemical characterizations, operando Raman spectra, and DFT theoretical calculations have demonstrated the electrons in the P-CoOX/NiFe LDHs heterointerfaces are easily transferred from Ni2+ to Co3+ because that the amorphous configuration of P-CoOX can well induce Ni-O-Co orbital coupling. The electron transfer of Ni2+ to the surrounding Fe3+ and Co3+ will lead to the unoccupied eg orbitals of Ni3+ that can promote water dissociation and accelerate *OOH migration to improve OER catalytic performance. The optimized P-CoOX/NiFe LDHs exhibit superior catalytic performance for OER with a very low overpotential of 265 mV at 300 mA cm-2 and excellent long-term stability of 500 h with almost no attenuation at 100 mA cm-2. This work will provide a new method to design high-performance NiFe LDHs-based catalysts for OER.
ABSTRACT
Flexible rechargeable Zn-air batteries (FZABs) exhibit high energy density, ultra-thin, lightweight, green, and safe features, and are considered as one of the ideal power sources for flexible wearable electronics. However, the slow and high overpotential oxygen reaction at the air cathode has become one of the key factors restricting the development of FZABs. The improvement of activity and stability of bifunctional catalysts has become a top priority. At the same time, FZABs should maintain the battery performance under different bending and twisting conditions, and the design of the overall structure of FZABs is also important. Based on the understanding of the three typical configurations and working principles of FZABs, this work highlights two common strategies for applying bifunctional catalysts to FZABs: 1) powder-based flexible air cathode and 2) flexible self-supported air cathode. It summarizes the recent advances in bifunctional oxygen electrocatalysts and explores the various types of catalyst structures as well as the related mechanistic understanding. Based on the latest catalyst research advances, this paper introduces and discusses various structure modulation strategies and expects to guide the synthesis and preparation of efficient bifunctional catalysts. Finally, the current status and challenges of bifunctional catalyst research in FZABs are summarized.
ABSTRACT
To overcome the trade-off challenge encountered in the engineering of alginate lyase AlyG2 from Seonamhaeicola algicola Gy8T and to expand its potential industrial applications, we devised a two-step strategy encompassing activity enhancement followed by thermal stability engineering. To enhance the specific activity of efficient AlyG2, we strategically substituted residues with bulky steric hindrance proximal to the active pocket with glycine or alanine. This led to the generation of three promising positive mutants, with particular emphasis on the T91S mutant, exhibiting a 1.91-fold specific activity compared to the wild type. To mitigate the poor thermal stability of T91S, mutants with negative ΔΔG values in the thermal flexibility region were screened out. Notably, the S72Ya mutant not only displayed 17.96 % further increase in specific activity but also exhibited improved stability compared to T91S, manifesting as a remarkable 30.97 % increase in relative activity following a 1-hour incubation at 42 °C. Furthermore, enhanced kinetic stability was observed. To gain deeper insights into the mechanism underlying the enhanced thermostability of the S72Ya mutant, we conducted molecular dynamics simulations, principal component analysis (PCA), dynamic cross-correlation map (DCCM), and free energy landscape (FEL) analysis. The results unveiled a reduction in the flexibility of the surface loop, a stronger correlation dynamic and a narrower motion subspace in S72Ya system, along with the formation of more stable hydrogen bonds. Collectively, our findings suggest amino acids substitutions resulting in smaller side chains proximate to the active site can positively impact enzyme activity, while reducing the flexibility of surface loops emerges as a pivotal factor in conferring thermal stability. These insights offer valuable guidance and a framework for the engineering of other enzyme types.
Subject(s)
Enzyme Stability , Molecular Dynamics Simulation , Polysaccharide-Lyases , Polysaccharide-Lyases/chemistry , Polysaccharide-Lyases/genetics , Polysaccharide-Lyases/metabolism , Kinetics , Temperature , Protein Engineering/methods , Mutation , Amino Acid Substitution , Mutagenesis, Site-DirectedABSTRACT
The development of efficient urea oxidation reaction (UOR) catalysts helps UOR replace the oxygen evolution reaction (OER) in hydrogen production from water electrolysis. Here, we prepared Fe-doped Ni2P/NiSe2 composite catalyst (Fe-Ni2P/NiSe2-12) by using phosphating-selenizating and acid etching to increase the intrinsic activity and active areas. Spectral characterization and theoretical calculations demonstrated that electrons flowed through the Ni-P-Fe-interface-Ni-Se-Fe, thus conferring high UOR activity to Fe-Ni2P/NiSe2-12, which only needed 1.39 V vs RHE to produce the current density of 100 mA cm-2. Remarkably, this potential was 164 mV lower than that required for the OER under the same conditions. Furthermore, EIS demonstrated that UOR driven by the Fe-Ni2P/NiSe2-12 exhibited faster interfacial reactions, charge transfer, and current response compared to OER. Consequently, the Fe-Ni2P/NiSe2-12 catalyst can effectively prevent competition with OER and NSOR, making it suitable for efficient hydrogen production in UOR-assisted water electrolysis. Notably, when water electrolysis is operated at a current density of 40 mA cm-2, this UOR-assisted system can achieve a decrease of 140 mV in the potential compared to traditional water electrolysis. This study presents a novel strategy for UOR-assisted water splitting for energy-saving hydrogen production.
ABSTRACT
A long-term goal of rechargeable zinc-air batteries (ZABs) has always been to design bifunctional electrocatalysts that are robust, effective, and affordable for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). It has become a feasible method to construct metal/metal oxide interfaces to achieve superior electrocatalytic performance for ORR and OER by enhanced charge transfer. In this study, Co/Co3O4 heterojunctions were successfully prepared and encased in porous N-doped mesoporous carbon (Co/Co3O4@NC) via a simple condensation-carbonization-etching method. The extensive specific surface area of Co/Co3O4@NC facilitates effective interaction between the electrolyte and the catalyst, thereby enabling sufficient exposure of active sites for the ORR and the OER, consequently enhancing the rate of transport of active species. The well-designed Co/Co3O4@NC delivers superior ORR catalytic activity with a half-wave potential of 0.82 V (vs RHE) and a low overpotential of 347 mV at 10 mA cm-2 for OER in alkaline solution. The power density of Co/Co3O4@NC-based alkaline aqueous ZAB (156.5 mW cm-2) is superior to the commercial Pt/C + IrO2-based alkaline aqueous ZAB, and the cycling stability of ZAB is up to 220 h. In addition, Co/Co3O4@NC-based ZAB shows a high power density (50.1 mW cm-2). The construction of metal/metal oxide heterojunction encased in N-doped mesoporous carbon provides a novel route for the design of bifunctional electrocatalysts for high-performance ZABs.
ABSTRACT
Periodontitis represents a severe inflammatory illness in tooth supporting tissue. It has been supported that cAMP response element binding protein 1 (CREB1), a common transcription factor, extensively participates in osteogenic differentiation. Here, the current study was to look into the impacts of CREB1 on the process of periodontitis and its possible action mechanism. After human periodontal ligament stem cells (PDLSCs) were challenged with zoledronic acid (ZA), CREB1 expression was examined with RT-qPCR and western blotting. CCK-8 assay appraised cell activity. Following CREB1 elevation or/and vascular endothelial growth factor (VEGF) silencing in ZA-treated PDLSCs, CCK-8 and TUNEL assays separately estimated cell viability and apoptosis. Western blotting tested the expression of apoptosis- and osteogenic differentiation-associated proteins. ALP staining measured PDLSCs osteogenic ability and ARS staining estimated mineralized nodule formation. JASPAR predicted the potential binding of CREB1 with VEGF promoter, which was then testified by ChIP and luciferase reporter assays. RT-qPCR and western blotting tested VEGF expression. CREB1 expression was declined in ZA-exposed PDLSCs and CREB1 elevation exacerbated the viability and osteogenic differentiation while obstructed the apoptosis of PDLSCs. Additionally, CREB1 bond to VEGF promoter and transcriptionally activated VEGF expression. Further, VEGF absence partially stimulated the apoptosis while suppressed the osteogenic differentiation of CREB1-overexpressing PDLSCs treated by ZA. To be concluded, CREB1 might activate VEGF transcription to obstruct the apoptosis while contribute to the osteogenic differentiation of ZA-treated PDLSCs.
Subject(s)
Osteogenesis , Periodontitis , Humans , Apoptosis/genetics , Cell Differentiation/physiology , Cell Proliferation , Cells, Cultured , Cyclic AMP Response Element-Binding Protein/metabolism , Osteogenesis/physiology , Periodontal Ligament , Periodontitis/metabolism , Signal Transduction/physiology , Sincalide/metabolism , Stem Cells , Vascular Endothelial Growth Factor A/genetics , Vascular Endothelial Growth Factor A/metabolism , Zoledronic Acid/pharmacology , Zoledronic Acid/metabolismABSTRACT
Compared with the traditional electrolysis of water to produce hydrogen, urea-assisted electrolysis of water to produce hydrogen has significant advantages and has received extensive attention from researchers. Unfortunately, urea oxidation reaction (UOR) involves a complex six-electron transfer process leading to high overpotential, which forces researchers to develop high-performance UOR catalysts to drive the development of urea-assisted water splitting. Based on the UOR mechanism and extensive literature research, this review summarizes the strategies for preparing highly efficient UOR catalysts. First, the UOR mechanism is introduced and the characteristics of excellent UOR catalysts are pointed out. Aiming at this, the following modulation strategies are proposed to improve the catalytic performance based on summarizing various literature: 1) Accelerating the active phase formation to reduce initial potential; 2) Creating double active sites to trigger a new UOR mechanism; 3) Accelerating urea adsorption and promoting CâN bond cleavage to ensure the effective conduct of UOR; 4) Promoting the desorption of CO2 to improve stability and prevent catalyst poisoning; 5) Promoting electron transfer to overcome the inherent slow dynamics of UOR; 6) Increasing active sites or active surface area. Then, the application of UOR in electrochemical devices is summarized. Finally, the current deficiencies and future directions are discussed.
ABSTRACT
Transition metal nitrides (TMNs) have become excellent substitutes for precious metals such as Pt and Ir in the field of electrocatalysis because of their excellent electrocatalytic performance, high conductivity, good corrosion resistance and stability. As we all know, the commonly utilized carbon-based materials corrode easily during electrocatalysis, which will lead to catalyst falling off and agglomeration. Compared with carbon-based materials, TMNs have stronger corrosion resistance and higher stability. In the metal nitrides, a variety of chemical bonds (metal bond, ionic bond and covalent bond) coexist, among which the ionic bond between metal atoms and nitrogen atoms can make the d-band shrink and narrow, which leads to TMNs having characteristics similar to precious metals in the electrocatalytic process; thus, they can be used as a substitute for precious metal catalysts. In this paper, the synthesis method and catalytic principle of transition metal nitrides and their applications in the fields of hydrogen evolution reaction (HER), oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) are discussed, and the shortcomings of TMNs as a catalyst, the challenges faced in catalyst research and the developments and prospects for the future are pointed out.
ABSTRACT
MXenes are a class of two-dimensional materials with a graphene-like structure, which have excellent optical, biological, thermodynamic, electrical and magnetic properties. Due to the diversity resulting from the combination of transition metals and C/N, the MXene family has expanded to more than 30 members and been applied in many fields with broad application prospects. Among their applications, electrocatalytic applications have achieved many breakthroughs. Therefore, in this review, we summarize the reports on the preparation of MXenes and their application in electrocatalysis published in the last five years and describe the two main methods for the preparation of MXenes, i.e., bottom-up and top to bottom synthesis. Different methods may change the structure or surface termination of MXenes, and accordingly affect their electrocatalytic performance. Furthermore, we highlight the application of MXenes in the electrocatalytic hydrogen evolution reaction (HER), oxygen evolution reaction (OER), oxygen reduction reaction (ORR), carbon dioxide reduction reaction (CO2RR), nitrogen reduction reaction (NRR), and multi-functionalization. It can be concluded that the electrocatalytic properties of MXenes can be modified by changing the type of functional groups or doping. Also, MXenes can be compounded with other materials to produce electronic coupling and improve the catalytic activity and stability of the resulting composites. In addition, Mo2C and Ti3C2 are two types of MXene materials that have been widely studied in the field of electrocatalysis. At present, research on the synthesis of MXenes is focused on carbides, whereas research on nitrides is rare, and there are no synthesis methods meeting the requirements of green, safety, high efficiency and industrialization simultaneously. Therefore, it is very important to explore environmentally friendly industrial production routes and devote more research efforts to the synthesis of MXene nitrides.
ABSTRACT
Bimetallic niobium-doped aluminum clusters, NbAln-/0 (n = 3-12), are investigated through a synergetic combination of size-selected anion photoelectron spectroscopy and theoretical calculations. It is found that the dominant structures of NbAln- anions with n = 3-8 can be described by gradually adding Al atoms to the NbAl3- core. Starting from n = 9, the lowest-energy geometric structures of NbAl9-12- transform into bilayer structures. In particular, NbAl12- has a C3v symmetric structure, which can be viewed as a NbAl6 regular hexagon over a bowl-shaped Al6 structure. More detailed analyses indicate that NbAl9 and NbAl12- possess unusual stability, which may be attributed to their closed-shell electron configurations with superatomic features.
ABSTRACT
Most reports on signal peptides focus on their ability to affect the normal folding of proteins, thereby affecting their secreted expression, while few studies on its effects on enzymatic properties were published. Therefore, biochemical characterization and comparison of alginate lyase rALYI1/rALYI1-1 (rALYI1: without signal peptides; rALYI1-1:with signal peptides) were conducted in our study, and the results showed that the signal peptide affected the biochemical properties, especially in temperature and pH. rALYI1 (32.15 kDa) belonging to polysaccharide lyase family 7 was cloned from sea-cucumber-gut bacterium Tamlana sp. I1. The optimum temperature of both rALYI1 and rALYI1-1 was 40 °C, but the former had a wider optimum temperature range and better thermal stability. The optimum pH of rALYI1 and rALYI1-1 were 7.6 and 8.6, respectively. The former was more stable and acid resistant. Noticeably, rALYI1 was a salt-activated enzyme and displayed remarkable salt tolerance. Alginate, an essential polysaccharide in algae and Pseudomonas aeruginosa biofilms, is composed of α-L-guluronate and ß-D-mannuronate. It is also found in our study that rALYI1 is also effective in removing mature biofilms compared with controls. In conclusion, the signal peptide affects several biochemical properties of the enzyme, and alginate lyase rALYI1 may be an effective method for inhibiting biofilm formation of Pseudomonas aeruginosa.
Subject(s)
Biofilms , Flavobacteriaceae , Polysaccharide-Lyases , Protein Sorting Signals , Pseudomonas aeruginosa , Alginates/chemistry , Alginates/metabolism , Biofilms/drug effects , Hydrogen-Ion Concentration , Polysaccharide-Lyases/chemistry , Polysaccharide-Lyases/pharmacology , Pseudomonas aeruginosa/physiology , Substrate Specificity , Flavobacteriaceae/enzymologyABSTRACT
Purple of Cassius is a pigment based on a gold colloid that has been known for hundreds of years. It has had a profound influence on modern nanoscience. But the origin of the small size of the Au nanoparticles (NPs) and their superior stability remains ambiguous. The experiments and characterization studies discussed here confirmed that SnCl2 functioned not only as a reducing agent but also as an effective surface capping agent through bimetallic Au-Sn bonding. This finding expands the types of Au NP stabilizer from traditional organic examples (e.g., thiolate or phosphine) to metallic examples. The formation of a Au-Sn interface also endows Au NPs with excellent activity and separability for the hydration of alkynes to ketones.
Subject(s)
Gold , Metal Nanoparticles , Alkynes , Gold Colloid , Ketones , Reducing AgentsABSTRACT
The structural and electronic properties of bimetallic oxide clusters, YCu2On- and YCu2On (n = 2-5), are investigated using anion photoelectron spectroscopy and density functional theory calculations. The experimental vertical detachment energies of YCu2O2-, YCu2O3-, YCu2O4-, and YCu2O5- were measured to be 1.59, 1.76, 3.85, and 3.78 eV, respectively. Vibrationally resolved photoelectron spectra have been obtained for YCu2O2-, with a spacing of 726 ± 80 cm-1 assigned to the Y-O stretching vibrational mode. It is found that YCu2O2- and YCu2O2 have C2v symmetric planar five-membered ring structures. YCu2O3- and YCu2O3 have C2v symmetric planar six-membered ring structures. The most stable structure of YCu2O4- is a quasi-planar structure which can be viewed as one O atom interacting with the Y atom of the YCu2O3 six-membered ring, while the most stable structure of YCu2O4 is a planar seven-membered ring. YCu2O5- and YCu2O5 have nonplanar structures, which can be viewed as an O2 unit interacting with the Y atom of the YCu2O3 six-membered ring. In YCu2O3,4,5-/0, the Y-O and Cu-O bonds are dominant, while the Y-Cu and Cu-Cu interactions are weak.
ABSTRACT
A Gram-stain-positive, orange-pigmented, rod-shaped and flagellated bacterial strain T12T was isolated from wetland soil in Kunyu Mountain Wetland in Yantai, China. The strain was able to grow at 15-40 °C (optimum 37 °C), at 0.0-9.0% NaCl (optimum 2%, w/v) and at pH 5.5-9.0 (optimum 8.5). A phylogenetic analysis based on the 16S rRNA gene sequence indicated that strain T12T is a member of the family Planococcaceae, sharing 97.6% and 97.1% sequence similarity with the type strains of Jeotgalibacillus salarius and Jeotgalibacillus marinus, respectively. Genome-based analyses revealed a genome size of 3,506,682 bp and a DNA G + C content of 43.7%. Besides, the genome sequence led to 55.0-74.6% average amino acid identity values and 67.8-74.7% average nucleotide identity values between strain T12T and the current closest relatives. Digital DNA-DNA hybridization of strain T12T with the type strains of Jeotgalibacillus proteolyticus and J. marinus demonstrated 19.0% and 20.3% relatedness, respectively. The chemotaxonomic analysis showed that the sole quinone was MK-7. The predominant cellular fatty acids were iso-C15:0, anteiso-C15:0, C16:1ω7c alcohol and iso-C14:0. The polar lipids consisted of an unidentified aminolipid, phosphatidylglycerol, diphosphatidylglycerol and two unidentified phospholipids. Based on the polyphasic characterization, strain T12T is considered to represent a novel species, for which the name Jeotgalibacillus aurantiacus sp. nov. is proposed. The type strain is T12T (= KCTC 43296 T = MCCC 1K07171T).
Subject(s)
Citrus sinensis , Planococcaceae , Bacterial Typing Techniques , Carotenoids , China , Citrus sinensis/genetics , DNA, Bacterial/genetics , Fatty Acids/chemistry , Multigene Family , Phospholipids/chemistry , Phylogeny , Planococcaceae/genetics , RNA, Ribosomal, 16S/genetics , Sequence Analysis, DNA , Soil , WetlandsABSTRACT
We report a combined experimental and theoretical study on the structures and chemical bonding of AuC2nH (n = 4-7) using photoelectron imaging and quantum chemical calculations. All the ground states of anions and neutral AuC2nH have a linear geometry. The electron affinities (EAs) are measured to be 2.063(5), 2.157(5), 2.220(5), and 2.267(5) eV for AuC2nH, n = 4-7, respectively. The photoelectron imaging data of AuC8H- and AuC10H- reveal major vibrational progressions in the Au-C stretching modes. The ground state stretching frequencies of the titled neutral molecules are 226, 193, 177, and 128 cm-1, respectively. By comparing the experimental ß value and theoretical molecular orbital analysis, we confirm that the CAM-B3LYP method is more suitable for describing the properties of such unsaturated long chains organogold clusters. The experimental and CAM-B3LYP methods give a big picture of the trend in EAs of AuC2nH. This shows that the EA value becomes larger with an increase in the carbon chain length, and it also shows a slow increment for larger n. The NRT analysis shows that the change of the Au-C bond order is not obvious as the number of carbon atoms increases, and the covalent character dominates the Au-C chemical bonds in these neutral species. The current study provides a wealth of electronic structure information about long-chain AuC2nH- (n = 4-7) and their corresponding neutral counterparts.
ABSTRACT
We investigated Cu4On - (n = 1-4) clusters through a synergetic combination of mass-selected anion photoelectron spectroscopy and density functional theory calculations. It is found that the most stable structure of Cu4O- is an irregular planar pentagon with a Cs symmetry. Those of Cu4O2 - and Cu4O3 - are non-planar structures with a Cs symmetry. The global minimum geometry of Cu4O4 - is a D4h symmetric quasi-square eight-membered ring with Cu-O bond lengths of â¼1.78 Å. The molecular orbital analyses suggest that Cu4O4 - has a large highest occupied molecular orbital and lowest unoccupied molecular orbital gap. The chemical bonding analyses and the calculations of the magnetically induced current density, and NICS(0) and NICS(1) values indicate that the D4h structure of Cu4O4 - is very stable and it has some aromaticity.
ABSTRACT
The structures and electronic properties of LaSin- (n = 2-6) anions and their neutral counterparts were investigated by anion photoelectron spectroscopy and theoretical calculations. The vertical detachment energies of the most stable structures of LaSin- (n = 2-6) were measured to be 1.28, 1.58, 2.30, 2.05, and 2.91 eV, respectively. The lowest-energy isomer of LaSi2- is an isosceles triangle with a C2v symmetry. For LaSi3-6- clusters, the most stable isomers are polyhedrons with La atom face-capping the Sin frameworks. The lowest-energy structures of neutral LaSi2,4,5 clusters are similar to their anionic counterparts. The most stable isomer of neutral LaSi3 is a planar structure with C2v symmetry, which is different from the triangular pyramid structure of LaSi3- anion. The lowest-energy isomer of LaSi6- is a C5v symmetric pentagonal bipyramid structure, while for neutral LaSi6 cluster, the C5v structure is not the most stable one. The natural population analysis showed that there is electron transfer from La atoms to Si atoms in LaSin-/0 (n = 2-6). The ZZ tensor component in isochemical shielding surfaces and the anisotropy of the induced current density analyses indicate that the most stable isomer of LaSi6- has aromaticity.
ABSTRACT
A Gram-stain-negative, pink-pigmented, aerobic, non-motile and rod-shaped bacterium, designated as strain H15T, was isolated from Acmaea sp., collected from Weihai, Shandong Province, China. The novel isolate was able to grow at 4-37 °C (optimum 33 °C), pH 5.5-9.0 (optimum 7.0) and with 0.0-7.0% NaCl (optimum 4%, w/v). Phylogenetic analysis based on 16S rRNA gene sequence comparisons revealed that the strain belonged to the family Rhodobacteraceae and was associated to the type strain of Pseudaestuariivita atlantica (96.7%). Genome analysis showed that the genome size was 3,893,398 bp and the DNA G + C content obtained from the draft genome sequence was 56.7%. The secondary metabolites predicated that the strain H15T contained one cluster of lasso peptide, one cluster of bacteriocin, two clusters of terpene production, two clusters of homoserine lactone and one cluster of beta lactone. The average amino acid identity, average nucleotide identity and digital DNA-DNA hybridization values between genome sequences of strain H15T and all the related strains compared were lower than 63.1, 72.0 and 19.7%, respectively. Based on the analysis of chemical components, the predominant cellular fatty acids were summed featured 8 (C18:1ω7c/ω6c, 46.1%), C20:1 ω7c (17.1%), the major polar lipids contained phosphatidylcholine, phosphatidylglycerol, phosphatidylethanolamine and an unidentified lipid and the predominant menaquinone was Q10. Therefore, the combined chemotaxonomic, phenotypic and phylogenetic data indicated that the strain was considered to represent a novel species of the genus Pseudaestuariivita and the name Pseudaestuariivita rosea sp. nov. was proposed for strain H15T (MCCC 1K04420T = KCTC 82505T).
Subject(s)
Gastropoda , Rhodobacteraceae , Animals , Bacterial Typing Techniques , DNA, Bacterial/genetics , Fatty Acids/analysis , Phospholipids , Phylogeny , RNA, Ribosomal, 16S/genetics , Rhodobacteraceae/genetics , Sequence Analysis, DNAABSTRACT
Strain C17T, a novel strain belonging to the phylum Actinobacteria, was isolated from a thermal power plant in Yantai, Shandong Province, China. Cells of strain C17T were Gram stain positive, aerobic, pink, non-motile and round with neat edges, showing optimum growth at 28 °C. Phylogenetically, strain C17T was a member of the class Actinobacteria, order Mycobacteriales, family Gordoniaceae. Phylogenetic analysis based on 16S rRNA gene sequence comparisons revealed that the related strains were Williamsia faeni JCM 17784 T and Williamsia limnetica KCTC 19981 T with pairwise sequence similarity of 98.5% for both strains. According to the draft genome sequence, the DNA G + C content was 64.7%. The average amino acid identity (AAI), average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values between genome sequences of strain C17T and the closest type strain W. faeni JCM 17784 T were 77.5, 77.9, and 20.7%, respectively. Predominant fatty acids were C16:0 (31.7%) and C18:1ω9c (26.8%). The major menaquinone was MK-9. The diagnostic phospholipids were phosphatidylethanolamine (PE), diphosphatidylglycerol (DPG), and phosphatidylinositol (PI). Therefore, the combined phenotypic, chemotaxonomic and phylogenetic data indicated that strain C17T was considered to represent a novel species of the genus Williamsia. Williamsia soli sp. nov. was proposed for strain C17T (= KCTC 49567 T = MCCC 1K04355T).