Activation of α7 nicotinic acetylcholine receptors inhibits hepatic necroptosis and ameliorates acute liver injury in mice.

BACKGROUND: Acute liver injury (ALI) is a disease characterized by severe liver dysfunction, caused by significant infiltration of immune cells and extensive cell death with a high mortality. Previous studies demonstrated that the α7 nicotinic acetylcholine receptor (α7nAChR) played a crucial role in various liver diseases. The hypothesis of this study was that activating α7nAChR could alleviate ALI and investigate its possible mechanisms. METHODS: ALI was induced by intraperitoneal injection of lipopolysaccharide (LPS)/D-galactosamine (D-Gal) in wild type (WT), α7nAChR knockout (α7nAChR -/-) and Sting mutation (Stinggt/gt) mice in the presence or absence of a pharmacological selective α7nAChR agonist (PNU-282987). The effects of α7nAChR on hepatic injury, inflammatory response, mitochondrial damage, necroptosis and infiltration of immune cells during ALI were assessed. RESULTS: The expression of α7nAChR in liver tissue was increased in LPS/D-Gal induced ALI mice. Compared to the age-matched WT mice, α7nAChR deficiency decreased the survival rate, exacerbated the hepatic injury accompanied with enhanced inflammatory response and oxidative stress, and aggravated hepatic mitochondrial damage and necroptosis. Conversely, pharmacological activation of α7nAChR by PNU-282987 displayed the opposite trends. Furthermore, PNU-282987 significantly reduced the proportion of infiltrating monocyte-derived macrophages (CD45+CD11bhiF4/80int), M1 macrophages (CD45+CD11b+F4/80+CD86 hiCD163low), Ly6Chi monocytes (CD45+CD11b+MHCⅡ lowLy6C hi), but increased the resident Kupffer cells (CD45+CD11bintF4/80 hiTIM4 hi) in the damaged hepatic tissues caused by LPS/D-Gal. Interestingly, α7nAChR deficiency promoted the STING signaling pathway under LPS/D-Gal stimulation, while PNU-282987 treatment significantly prevented its activation. Finally, it was found that Sting mutation abolished the protective effects against hepatic injury by activating α7nAChR. CONCLUSIONS: Our study revealed that activating α7nAChR could protect against LPS/D-Gal induced ALI by inhibiting hepatic inflammation and necroptosis possibly via regulating immune cells infiltration and inhibiting STING signaling pathway.

Establishment of pseudorabies virus latency and reactivation model in mice dorsal root ganglia culture.

Pseudorabies virus (PRV) belongs to the alpha herpesvirus family and is responsible for Aujeszky's disease in pigs. Similar to other alpha herpesviruses, PRV establishes a lifelong latent infection in trigeminal ganglion. These latently infected pigs serve as a reservoir for recurrent infections when reactivation is triggered, making the eradication of PRV a challenging task. However, the molecular mechanism underlying PRV latency and reactivation in neurons is still poorly understood due to limitations in the in vitro model. To establish a pseudorabies virus latency and reactivation model in primary neuron cultures, we isolated dorsal root ganglion (DRG) from newborn Kunming mice using a method named epineurium-pulling for DRG collection (EPDC) and cultured primary neurons in vitro. A dual-colour recombinant PRV BAC mRuby-VP16 was constructed and 0.5 multiplicity of infection (MOI) was found as an appropriate dose in the presence of aciclovir to establish latency. Reactivation was induced using UV-inactivated herpesviruses or a series of chemical inhibitors. Interestingly, we found that not only UV-PRV, but also UV-HSV-1 and UV-BHoV-5 were able to induce rapid PRV reactivation. The efficiency of reactivation for LY294002, forskolin, etoposide, dexamethasone, and acetylcholine was found to be dependent on their concentration. In conclusion, we developed a valuable model of PRV latency and reactivation, which provides a basis for future mechanism research.

A guided ion beam investigation of UO2+ thermodynamics and f orbital participation: Reactions of U+ + CO2, UO+ + O2, and UO+ + CO.

A guided ion beam tandem mass spectrometer was employed to study the reactions of U+ + CO2, UO+ + O2, and the reverse of the former, UO+ + CO. Reaction cross sections as a function of kinetic energy over about a three order of magnitude range were studied for all systems. The reaction of U+ + CO2 proceeds to form UO+ + CO with an efficiency of 118% ± 24% as well as generating UO2+ + C and UCO+ + O. The reaction of UO+ + O2 forms UO2+ in an exothermic, barrierless process and also results in the collision-induced dissociation of UO+ to yield U+. In the UO+ + CO reaction, the formation of UO2+ in an endothermic process is the dominant reaction, but minor products of UCO+ + O and U+ + (O + CO) are also observed. Analysis of the kinetic energy dependences observed provides the bond energies, D0(U+-O) = 7.98 ± 0.22 and 8.05 ± 0.14 eV, D0(U+-CO) = 0.73 ± 0.13 eV, and D0(OU+-O) = 7.56 ± 0.12 eV. The values obtained for D0(U+-O) and D0(OU+-O) agree well with the previously reported literature values. To our knowledge, this is the first experimental measurement of D0(U+-CO). An analysis of the oxide bond energies shows that participation of 5f orbitals leads to a substantial increase in the thermodynamic stability of UO2+ relative to ThO2+ and especially transition metal dioxide cations.

Novel 2-Amino-1,4-Naphthoquinone Derivatives Induce A549 Cell Death through Autophagy.

A series of 1,4-naphthoquinone derivatives containing were synthesized as anti-cancer agents and the crystal structure of compound 5a was confirmed by X-ray diffraction. In addition, the inhibitory activities against four cancer cell lines (HepG2, A549, K562, and PC-3) were tested, respectively, and compound 5i showed significant cytotoxicity on the A549 cell line with the IC50 of 6.15 µM. Surprisingly, in the following preliminary biological experiments, we found that compound 5i induced autophagy by promoting the recycling of EGFR and signal transduction in the A549 cell, resulting in the activation of the EGFR signal pathway. The potential binding pattern between compound 5i and EGFR tyrosine kinase (PDB ID: 1M17) was also identified by molecular docking. Our research paves the way for further studies and the development of novel and powerful anti-cancer drugs.

[Anatomic Abnormalities of Hippocampal Subfields in First-Episode Drug-Naïve Schizophrenia and Major Depressive Disorder: A Structural MRI Comparative Study].

Objective: To compare the structural changes along the longitudinal axis of hippocampus subfields between schizophrenia (SCZ) patients and major depressive disorder (MDD) patients in the early stage of their SCZ and MDD. Methods: Seventy-nine first-episode drug-naïve patients with SCZ, 48 first-episode drug-naïve patients with MDD, and 79 healthy controls (HC) were recruited and underwent assessment of clinical symptoms and magnetic resonance imaging (MRI) of the head. Following the calculation of hippocampal and subfield volumes with FreeSurfer, the volume of longitudinal subfields were summed up. Inter-group comparison of these indicators was made with the data of different groups and the correlation between clinical symptoms and the volumes of longitudinal subfields was analyzed. Results: Compared with HC, SCZ patients had smaller bilateral posterior hippocampus (left: t=－2.69, P=0.01; right: t=－2.90, P=0.004), while MDD patients exhibited no changes along the longitudinal axis of hippocampal subfields. In SCZ patients, the volume of bilateral posterior hippocampus was negatively correlated with the negative symptom scores of Positive and Negative Syndrome Scale (left: r=－0.29, P=0.01; right: r=－0.23, P=0.04). Conclusion: The smaller posterior hippocampus may be an imaging feature for distinguishing SCZ from MDD and may have contributed to the neuropathophysiological mechanism of SCZ in the early stage of the onset of the disease.

[Alkaloids from fruit of Lycium chinense var. potaninii].

Ten alkaloids(1-10) were isolated from the ethyl acetate extract of the fruit of Lycium chinense var. potaninii by silica gel, ODS, and preparative high performance liquid chromatography(HPLC), and identified by NMR and MS as methyl(2S)-[2-formyl-5-(hydroxymethyl)-1H-pyrrol-1-yl]-3-(phenyl)propanoate(1), methyl(2R)-[2-formyl-5-(methoxymethyl)-1H-pyrrol-1-yl]-3-(phenyl)propanoate(2), 3-hydroxy-4-ethyl ketone pyridine(3), indolyl-3-carbaldehyde(4),(R)-4-isobutyl-3-oxo-3,4-dihydro-1H-pyrrolo[2,1-c][1,4]oxazine-6-carbaldehyde(5),(R)-4-isopropyl-3-oxo-3,4-dihydro-1H-pyrrolo[2,1-c][1,4]oxazine-6-car-baldehyde(6), methyl(2R)-[2-formyl-5-(methoxymethyl)-1H-pyrrol-1-yl]-3-(4-hydroxyphenyl)propanoate(7), dimethyl(2R)-[2-formyl-5-(methoxymethyl)-1H-pyrrol-1-yl]butanedioate(8), 4-[formyl-5-(methoxymethyl)-1H-pyrrol-1-yl]butanoate(9), 4-[2-formyl-5-(methoxymethyl)-1H-pyrrol-1-yl]butanoic acid(10). All the compounds were isolated from the plant for the first time. Among them, compounds 1-3 were new compounds. Compounds 1-9 were evaluated for hypoglycemic activity in vitro with the palmitic acid-induced insulin resistance in HepG2 cells. At 10 µmol·L~(-1), compounds 4, 6, 7, and 9 can promote the glucose consumption of HepG2 cells with insulin resistance.

Association of E-Selectin Gene +A561C Polymorphism with Type 2 Diabetes in Chinese Population.

BACKGROUND: Diabetes is associated with endothelial cell dysfunction. E-selectin is an endothelial cell adhesion molecule, which is bound for endothelial cell activation. E-selectin gene+A561C polymorphism is associated with many different disorders: essential hypertension, stroke, angina pectoris, coronary heart disease, etc. But the association with type 2 diabetes remains unclear. Therefore, we aimed to investigate the role of E-selectin gene+A561C polymorphism and soluble E-selectin in type 2 diabetes in a Chinese population. METHODS: This study involved 317 patients with type 2 diabetes and 285 normal healthy controls. Genotyping of E-selectin gene+A561C polymorphism was examined by polymerase chain reaction-restricted fragments length polymorphism (PCR-RFLP). Soluble E-selectin was examined by enzyme linked immunosorbent assay (ELISA). Biochemical markers were measured by Roche 7600 Automated Biochemical Analyzer. RESULTS: We found that C allele frequency in E-selectin A561 C polymorphism of Chinese T2DM group was higher than control group. The level of soluble E-selectin in T2DM group was higher than control group. TC, TG, LDL-C, ApoB, and sE-selectin (soluble E-selectin) in AC and CC genotypes were higher than AA genotype. CONCLUSIONS: Our findings showed that E-selectin +A561C polymorphism was correlated in the Chinese population with type 2 diabetes. C allele and soluble E-selectin may be predisposing factors of Chinese population with type 2 diabetes.

Two new cadinane-type sesquiterpenoid glycosides from Dryopteris fragrans with anti-inflammatory activities.

Two new cadinane-type sesquiterpenoid glycosides, dryopteristerpeneA (1) and dryopteristerpeneB (2), were isolated from the aqueous extract of Dryopterisfragrans. Their structures were determined by spectroscopic data analysis and electronic circular dichroism (ECD) calculations. Compounds 1 and 2 exhibited inhibition on nitric oxide production in lipopolysaccharide induced RAW 264.7 macrophages with their IC50 values of 60.5 and 59.8 µM, respectively.

Antibacterial property, corrosion and discoloration resistance of pure copper containing Zn or Ni.

This study focused on the effects of Zn and Ni addition on the antibacterial properties and corrosion resistance of copper alloys. The antimicrobial properties of copper and copper alloys were evaluated using Escherichia coli ATCC 8739 bacterial strain by employing the overlay and plate counting methods. X-ray photoelectron spectroscopy (XPS) was used to analyze the surface composition of the alloy after contact with bacteria. A salt spray method was used to simulate an artificial sweat contact environment to test the discoloration and corrosion resistance of the alloy, and scanning electron microscopy (SEM) was used to analyze the film layer and surface material composition of the corroded samples. The addition of Ni reduced the antibacterial performance of pure copper; however, the antibacterial performance of the alloy remained fast and efficient after the addition of Zn. Moreover, the addition of Zn and Ni significantly improved the corrosion resistance and surface discoloration of copper alloys in artificial sweat environments. This study provided support for the future application of copper alloys as antimicrobial surface-contact materials with safer public and medical environments in the face of diseases spread by large populations. Supplementary Information: The online version contains supplementary material available at 10.1007/s12598-022-02098-8.

Reactions of U+ with H2, D2, and HD Studied by Guided Ion Beam Tandem Mass Spectrometry and Theory.

The kinetic energy-dependent reactions of the atomic actinide uranium cation (U+) with H2, D2, and HD were examined by guided ion beam tandem mass spectrometry. An average 0 K bond dissociation energy of D0(U+ - H) = 2.48 ± 0.06 eV is obtained by analysis of the endothermic product ion cross sections. Quantum chemistry calculations were performed for comparison with experimental thermochemistry, including high-level CASSCF-CASPT2-RASSI calculations of the spin-orbit corrections. CCSD(T) and the CASSCF levels show excellent agreement with experiment, whereas B3LYP and PBE0 slightly overestimate and the M06 approach badly underestimates the bond energy for UH+. Theory was also used to investigate the electronic structures of the reaction intermediates and potential energy surfaces. The experimental product branching ratio for the reaction of U+ with HD indicates that these reactions occur primarily via a direct reaction mechanism, despite the presence of a deep-well for UH2+ formation according to theory. The reactivity and hydride bond energy for U+ are compared with those for transition metal, lanthanide, and actinide cations, and periodic trends are discussed. These comparisons suggest that the 5f electrons on uranium are largely core and uninvolved in the reactive chemistry.

Cardamonin protects against lipopolysaccharide-induced myocardial contractile dysfunction in mice through Nrf2-regulated mechanism.

In patients with sepsis, lipopolysaccharide (LPS) from the outer membrane of gram-negative bacteria triggers cardiac dysfunction and heart failure, but target therapy for septic cardiomyopathy remains unavailable. In this study we evaluated the beneficial effects of cardamonin (CAR), a flavone existing in Alpinia plant, on endotoxemia-induced cardiac dysfunction and the underlying mechanisms with focus on oxidative stress and apoptosis. Adult mice were exposed to LPS (4 mg/kg, i.p. for 6 h) prior to functional or biochemical assessments. CAR (20 mg/kg, p.o.) was administered to mice immediately prior to LPS challenge. We found that LPS challenge compromised cardiac contractile function, evidenced by compromised fractional shortening, peak shortening, maximal velocity of shortening/relengthening, enlarged LV end systolic diameter and prolonged relengthening in echocardiography, and induced apoptosis, overt oxidative stress (O2- production and reduced antioxidant defense) associated with inflammation, phosphorylation of NF-κB and cytosolic translocation of transcriptional factor Nrf2. These deteriorative effects were greatly attenuated or mitigated by CAR administration. However, H&E and Masson's trichrome staining analysis revealed that neither LPS challenge nor CAR administration significantly affected cardiomyocyte cross-sectional area and interstitial fibrosis. Mouse cardiomyocytes were treated with LPS (4 µg/mL) for 6 h in the absence or presence of CAR (10 µM) in vitro. We found that addition of CAR suppressed LPS-induced defect in cardiomyocyte shortening, which was nullified by the Nrf2 inhibitor ML-385 or the NF-κB activator prostratin. Taken together, our results suggest that CAR administration protects against LPS-induced cardiac contractile abnormality, oxidative stress, apoptosis, and inflammation through Nrf2- and NF-κB-dependent mechanism.

[Effects of electroacupuncture with different courses on the synaptic structure and synaptic function-related proteins in mice with radiation-induced brain injury].

The aim of the present study was to investigate the effects of different courses of electroacupuncture on synaptic structure and synaptic function-related proteins expression in the hippocampal CA1 region of radiation-induced brain injury mice. Sixty C57BL/6J male mice were randomly divided into control group, radiation-induced brain injury model group, 1-week electroacupuncture group (EA1), 2-week electroacupuncture group (EA2), 3-week electroacupuncture group (EA3), and electroacupuncture-control (EA-Ctrl) group. The mice in model group were exposed to X-ray irradiation (8 Gy, 10 min) to establish radiation-induced brain injury model. The mice in EA groups were acupunctured at electroacupuncture points (Baihui, Fengfu and bilateral Shenshu) for 1 week, 2 weeks and 3 weeks respectively after radiation. Immunohistochemistry was used to observe synaptic structure in hippocampal CA1 region. The expressions of brain-derived neurotrophic factor (BDNF), synapsin-1 and postsynaptic density 95 (PSD95) in the hippocampal CA1 region of each group were detected by RT-PCR and Western blotting. The results showed that the nuclear gap in model and EA-Ctrl groups was significantly decreased compared to control group, however nucleus to cytoplasm ratio was significantly increased. The synaptic cleft, postsynaptic density (PSD) thickness, the mitochondrial surface density, volume density and specific surface area were significantly reduced. Compared with model group, the nucleus to cytoplasm ratio of EA2 group was significantly decreased, the PSD thickness and mitochondrial volume density were significantly increased; the nuclear gap of EA3 group was significantly increased, nucleus to cytoplasm ratio was significantly decreased, synaptic cleft and PSD thickness were significantly increased, and the mitochondrial surface density and specific surface area were all increased significantly. In addition, compared with the control group, the gene and protein expressions of BDNF, synapsin-1 and PSD95 in the hippocampal CA1 region of the model group and EA-Ctrl group were significantly decreased. However, compared with the model group, the gene expression of synapsin-1 in EA groups was significantly up-regulated, the gene expression of BDNF in EA1 and EA2 groups was significantly up-regulated, and the gene expression of PSD95 in EA2 group was significantly up-regulated. Moreover, the protein expressions of BDNF, synapsin-1 and PSD95 of EA groups were significantly up-regulated compared with the model group. These results indicate that the synaptic structure and the expression of synaptic function-related proteins in hippocampal CA1 region were injured by radiation exposure, whereas electroacupuncture intervention can significantly improve the synaptic structure and function damage caused by radiation.

A 34-Electron Superatom Ag78 Cluster with Regioselective Ternary Ligands Shells and Its 2D Rhombic Superlattice Assembly.

Herein, we report a 78-nuclei silver nanocluster (NC) [Ag78 (i PrPhS)30 (dppm)10 Cl10 ]4+ (SD/Ag78a; dppm=bis-(diphenylphosphino)methane) that was synthesized through a one-pot reaction using [Ag(pz)]n as precursor (Hpz=pyrazole) and further characterized by X-ray crystallography. SD/Ag78a shows a core-shell structure comprised of an all-metallic Ag53 kernel surrounded by an Ag25 discontinuous metal-organic shell. The Ag53 kernel is an Ag13 Ino decahedron encaged by an Ag40 drum-like shell, while the Ag25 shell consists of two Ag10 S10 P10 Cl5 rings and five S-Ag-S staples. Three types of ligands regioselectively cap on the surface of the Ag78 NC, forming diverse metal-ligand interfacial structures. The NC is a closed-shell 34-electron superatom with +4 charge state and shows highly featured molecule-like absorption spectra in the UV/Vis region with a maximum around 493 nm. The rhombic superlattice assembled from SD/Ag78a through intercluster C-H⋅⋅⋅π interactions can be formed by a simple drop-casting treatment.

microRNA-802 accelerates hepatocellular carcinoma growth by targeting RUNX3.

Hepatocellular carcinoma (HCC) is one of the most common malignancies worldwide. Prognosis is often unfavorable. In this study, the effects of microRNA-802 (miR-802) on HCC progression were assessed in vivo and in vitro. miR-802 was found to be significantly upregulated in HCC tumor tissue compared to paired adjacent nontumor tissue. In vitro, transfection with a miR-802 mimic accelerated SMMC-7721 cellular proliferation, increased accumulation of the cell-cycle S-phase cell populations, as well as cell migration. In vivo injection of a miR-802 agomir promoted HCC proliferation in nude mice. Targets of miR-802 were predicted by miRWalk, miRanda, RNA22, and Targetscan. By luciferase reporter assay RUNX3 was identified as a direct target of miR-802. As judged by western blot analysis, RUNX3 was upregulated when miR-802 was inhibited. These data demonstrate increased miR-802 expression in patients with HCC and that miR-802 overexpression promotes tumor cell growth, in a RUNX3-dependent manner.

Feedback inhibition of bovine herpesvirus 5 replication by dual-copy bhv5-miR-B10-3p.

Bovine herpesvirus 5 (BoHV-5) is a pathogen of cattle responsible for fatal meningoencephalitis. Like alpha herpesvirus subfamily members, BoHV-5 also encodes microRNA in lytic infections of epithelial cells. BoHV-5-miR-B10 was the most abundant miRNA detected in a high-throughput sequencing study. Here, we evaluated the kinetics of miR-B10 expression after BoHV-5 productive infection by stem-loop real-time quantitative PCR. miR-B10 candidate target sites in the virus were predicted, and BoHV-5 UL39 was confirmed as a target gene by dual-luciferase assay with the design of an miR-B10 tough decoy (TuD). The UL39 gene encoding ribonucleotide reductase (RR) large subunit plays an important role in the early stage of BoHV-5 lytic infection. As BoHV-5-miR-B10 is located in internal and terminal repeat regions, we generated a TuD gene-integrated BoHV-5 strain, which effectively down-regulated miR-B10-3p. Strikingly, the suppression of miR-B10-3p significantly improved BoHV-5 replication. Taking these findings together, our study established an efficient method to deliver and express TuD RNA for viral miRNA suppression, and demonstrated that virus-encoded miRNA suppresses viral-genome biogenesis with a feedback mode, which might serve as a brake for viral replication. Herpesviruses infect humans and a variety of animals. Almost all herpesviruses can encode miRNAs, but the functions of these miRNAs remain to be elucidated. Most herpesvirus-encoded miRNA harbours dual copies, which is difficult to be deleted by current genetic modulation. Here, we developed an efficient method to deliver and express TuD RNA to efficiently suppress viral miRNA with multiple copies. Using this method, we demonstrated for the first time that viral miRNA feedback regulates viral replication by suppressing the expression of RR.

The isoelectric point of proteins influences their translocation to the extrahaustorial matrix of the barley powdery mildew fungus.

Many biotrophic fungal plant pathogens develop feeding structures, haustoria, inside living plant cells, which are essential for their success. Extrahaustorial membranes (EHMs) surround haustoria and delimit the extrahaustorial matrices (EHMxs). Little is known about transport mechanisms across EHMs and what properties proteins and nutrients need in order to cross these membranes. To investigate this further, we expressed fluorescent proteins in the cytosol of infected barley leaf epidermal cells after particle bombardment and investigated properties that influenced their localisation in the powdery mildew EHMx. We showed that this translocation is favoured by a neutral isoelectric point (pI) between 6.0 and 8.4. However, for proteins larger than 50 kDa, pI alone does not explain their localisation, hinting towards a more complex interplay between pI, size, and sequence properties. We discuss the possibility that an EHM translocon is involved in protein uptake into the EHMx.

Folium Sennae and emodin reverse airway smooth muscle contraction.

The objective of this project was to find a bronchodilatory compound from herbs and clarify the mechanism. We found that the ethanol extract of Folium Sennae (EEFS) can relax airway smooth muscle (ASM). EEFS inhibited ASM contraction, induced by acetylcholine, in mouse tracheal rings and lung slices. High-performance liquid chromatography assay showed that EEFS contained emodin. Emodin had a similar reversal action. Acetylcholine-evoked contraction was also partially reduced by nifedipine (a selective inhibitor of L-type voltage-dependent Ca2+ channels, LVDCCs), YM-58483 (a selective inhibitor of store-operated Ca2+ entry, SOCE), as well as Y-27632 (an inhibitor of Rho-associated protein kinase). In addition, LVDCC- and SOCE-mediated currents and cytosolic Ca2+ elevations were inhibited by emodin. Emodin reversed acetylcholine-caused increases in phosphorylation of myosin phosphatase target subunit 1. Furthermore, emodin, in vivo, inhibited acetylcholine-induced respiratory system resistance in mice. These results indicate that EEFS-induced relaxation results from emodin inhibiting LVDCC, SOCE, and Ca2+ sensitization. These findings suggest that Folium Sennae and emodin may be new sources of bronchodilators.

The decisive role of 4f-covalency in the structural direction and oxidation state of XPrO compounds (X: group 13 to 17 elements).

Lanthanide oxo compounds are of vital importance in lanthanide chemistry, as well as in environmental and materials sciences. Praseodymium, as an exceptional element in lanthanides which can form a +V formal oxidation state (OSf) besides the dominant +III among the 4f-block element, displays the significant participation of the Pr 4f orbitals in bonding interactions which is commonly crucial in stabilizing the high oxidation state of Pr in PrO2+ and NPrO species. Here, we report a systematic theoretical study on the structures and stabilities of a series of XPrO (X: B, Al, C, Si, N, P, As, O, S, F, Cl) compounds along with [XPrO]+ cation (X: O, S) and [X3PrO] complexes (X: F and Cl). This work reveals that Pr is able to achieve the lowest and highest OSf and the OSf exhibits periodic variation from +I in BOPr and AlOPr to +II in SiOPr to +III in CPrO, FPrO, ClPrO and AsPrO to +IV in OPrO and SPrO and even to +V in NPrO, [OPrO]+, [SPrO]+, F3PrO and Cl3PrO. We found that the molecular structures are correlated to the Pr oxidation state due to the highly important 4f orbital in the chemical bonding of the high oxidation state compounds. Thus, not only the electronegativity of the ligand but also the quasi-degenerate Pr valence 4f orbitals, namely energetic covalency, control the oxidation state and play a fundamental role in affecting the electronic structural stability of Pr(v) compounds as well. This work demonstrates the structurally directing role of the f-orbital in the formation of the linear structure and is constructive for achieving the higher oxidation state of a given element by tuning the ligand.

Expanding RNA binding specificity and affinity of engineered PUF domains.

Specific manipulation of RNA is necessary for the research in biotechnology and medicine. The RNA-binding domains of Pumilio/fem-3 mRNA binding factors (PUF domains) are programmable RNA binding scaffolds used to engineer artificial proteins that specifically modulate RNAs. However, the native PUF domains generally recognize 8-nt RNAs, limiting their applications. Here, we modify the PUF domain of human Pumilio1 to engineer PUFs that recognize RNA targets of different length. The engineered PUFs bind to their RNA targets specifically and PUFs with more repeats have higher binding affinity than the canonical eight-repeat domains; however, the binding affinity reaches the peak at those with 9 and 10 repeats. Structural analysis on PUF with nine repeats reveals a higher degree of curvature, and the RNA binding unexpectedly and dramatically opens the curved structure. Investigation of the residues positioned in between two RNA bases demonstrates that tyrosine and arginine have favored stacking interactions. Further tests on the availability of the engineered PUFs in vitro and in splicing function assays indicate that our engineered PUFs bind RNA targets with high affinity in a programmable way.

[Analysis of differential genes related to dormancy release of Paris polyphylla var. chinensis seeds by transcriptome sequencing].

The study aims at exploring the expression of differential genes and related metabolic pathways in the process of seed dormancy release. The dormant embryo and the dormant released embryo of Paris polyphylla var. chinensis were used as the test materials, a new generation high-throughput sequencing methods to sequence the transcriptome of the samples was used to carry out systematic bioinformatics analysis. We obtained 62 882 650 and 62 263 366 clean reads from the DNA libraries of the samples before and after dormancy breaking. A total of 69 248 differentially expressed genes(DEGs) were obtained, 56 426 up-regulated genes and 12 822 down-regulated genes. There are 138 267 differentially expressed genes in the process of embryo dormancy release, which were annotated by GO function to 58 subclasses of biological processes, molecular functions and cell components. The annotated differentially expressed genes were closely related to metabolic processes, biological regulation, cell component synthesis and enzyme catalytic activity. We found 139 metabolic pathways through pathway analysis of 58 722 differentially expressed genes. Before and after dormancy, DEGs were mainly enriched in carbon metabolism, secondary metabolite biosynthesis and polysaccharide metabolism. Based on the annotation results in KEGG database, we found 16 metabolic pathways related to the dormancy release of P. polyhoylla var. chinensis. A large number of differentially expressed genes were involved in embryo morphogenesis, polysaccharide decomposition and protein synthesis during seed development and dormancy release. It involves the interaction of multiple metabolic pathways and constitutes a complex regulation network for dormancy relief.