Interaction of tau with HNRNPA2B1 and N6-methyladenosine RNA mediates the progression of tauopathy.

The microtubule-associated protein tau oligomerizes, but the actions of oligomeric tau (oTau) are unknown. We have used Cry2-based optogenetics to induce tau oligomers (oTau-c). Optical induction of oTau-c elicits tau phosphorylation, aggregation, and a translational stress response that includes stress granules and reduced protein synthesis. Proteomic analysis identifies HNRNPA2B1 as a principle target of oTau-c. The association of HNRNPA2B1 with endogenous oTau was verified in neurons, animal models, and human Alzheimer brain tissues. Mechanistic studies demonstrate that HNRNPA2B1 functions as a linker, connecting oTau with N6-methyladenosine (m6A) modified RNA transcripts. Knockdown of HNRNPA2B1 prevents oTau or oTau-c from associating with m6A or from reducing protein synthesis and reduces oTau-induced neurodegeneration. Levels of m6A and the m6A-oTau-HNRNPA2B1 complex are increased up to 5-fold in the brains of Alzheimer subjects and P301S tau mice. These results reveal a complex containing oTau, HNRNPA2B1, and m6A that contributes to the integrated stress response of oTau.

OpenXGR: a web-server update for genomic summary data interpretation.

How to effectively convert genomic summary data into downstream knowledge discovery represents a major challenge in human genomics research. To address this challenge, we have developed efficient and effective approaches and tools. Extending our previously established software tools, we here introduce OpenXGR (http://www.openxgr.com), a newly designed web server that offers almost real-time enrichment and subnetwork analyses for a user-input list of genes, SNPs or genomic regions. It achieves so through leveraging ontologies, networks, and functional genomic datasets (such as promoter capture Hi-C, e/pQTL and enhancer-gene maps for linking SNPs or genomic regions to candidate genes). Six analysers are provided, each doing specific interpretations tailored to genomic summary data at various levels. Three enrichment analysers are designed to identify ontology terms enriched for input genes, as well as genes linked from input SNPs or genomic regions. Three subnetwork analysers allow users to identify gene subnetworks from input gene-, SNP- or genomic region-level summary data. With a step-by-step user manual, OpenXGR provides a user-friendly and all-in-one platform for interpreting summary data on the human genome, enabling more integrated and effective knowledge discovery.

I Single-Atom Doped P-Rich CoPn Nanocluster@CoP with Enhanced HER.

Constructing I single-atom (ISA) doped CoP electrocatalyst for HER is extremely challenging and has not been reported to date. Herein, an ISA doping-phosphatization strategy is proposed to prepare a novel I single-atom doped P-rich CoPn nanocluster@CoP electrocatalyst (ISA-CoPn/CoP) with enhanced HER performance first. ISA-CoPn/CoP shows a low overpotential of only 44 and 81 mV in 0.5 m H2SO4 solution, to drive a current density of 10 and 100 mA cm-2. ISA and P-rich CoPn nanocluster show unique synergies, which can optimize the H adsorption energy and accelerate the kinetics of HER in the CoP system. The intermediate I─H bond vibration peak is directly observed through in situ Raman testing, demonstrating that ISA doping helps accelerate the HER process. Additionally, the ΔGH of ISA-CoPn/CoP is only 0.05 eV by density functional theory (DFT) calculation, which is conducive to H2 evolution.

Three-Dimensional Bimetallic Ammonium K-Eu Nitrate with a Rare (6,6)-Connected Ion Topology Exhibiting Structural Phase Transition and Photoluminescence Properties.

A K-Eu bimetallic ammonium metal-nitrate three-dimensional (3D) framework incorporating R-N-methyl-3-hydroxyquinuclidine, (RM3HQ)2KEu(NO3)6 (RM3HQ = R-N-methyl-3-hydroxyquinuclidine, 1), was characterized and reported. Distinguishing from the former hybrid rare-earth double perovskites, 1 adopts a mixed corner- and face-sharing K+/Eu3+-centered polyhedral connectivity to form a 3D inorganic framework, showing a rare (6, 6)-connected ion topology with a 66 framework. Notably, 1 exhibits clear phase transition, and the switchable thermodynamic behavior is confirmed by variable-temperature dielectric measurements and second-harmonic generation response. Moreover, 1 also shows photoluminescence properties. The activator Eu3+ plays a crucial role in this process, leading to a significant narrow emission at 592 nm with a photoluminescence quantum yield (PLQY) of 20.76%. The fluorescence lifetime (FLT) of 1 is 4.32 ms. This finding enriches the bimetallic hybrid system for potential electronic and/or luminescence applications.

Gas-Liquid Interface Route to Hybrid Copper Bromine Perovskite Single-Crystal Membrane with Dielectric Transitions and Ferromagnetic Exchanges.

Single-crystal membranes (SCMs) show great promise in the fields of sensors, light-emitting diodes, and photodetection. However, the growth of a large-area single-crystal membranes is challenging. We report a new organic-inorganic SCMs [HCMA]2CuBr4 (HCMA = cyclohexanemethylamine) crystallized at the gas-liquid interface. It also has low-temperature ferromagnetic order, high-temperature dielectric anomalies, and narrow band gap indirect semiconductor properties. Specifically, the reversible phase transition of the compound occurs at 350/341 K on cooling/heating and exhibits dielectric anomalies and stable switching performance near the phase transition temperature. The ferromagnetic exchange interaction in the inorganic octahedra and the organic layer enables ferromagnetic ordering at low-temperature 10 K. Finally, the single crystal exhibits an indirect semiconducting property with a narrow band gap of 0.99 eV. Such rich multichannel physical properties make it a potential application in photodetection, information storage and sensors.

A phosphoglycerate mutase 1 allosteric inhibitor overcomes drug resistance to EGFR-targeted therapy via disrupting IL-6/JAK2/STAT3 signaling pathway in lung adenocarcinoma.

Resistance to epidermal growth factor receptor (EGFR) inhibitors, from the first-generation erlotinib to the third generation osimertinib, is a clinical challenge in the treatment of patients with EGFR-mutant lung adenocarcinoma. Our previous work found that a novel allosteric inhibitor of phosphoglycerate mutase 1 (PGAM1), HKB99, restrains erlotinib resistance in lung adenocarcinoma cells. However, the role of HKB99 in osimertinib resistance and its underlying molecular mechanism remains to be elucidated. Herein, we found that IL-6/JAK2/STAT3 signaling pathway is aberrantly activated in both erlotinib and osimertinib resistant cells. Importantly, HKB99 significantly blocks the interaction of PGAM1 with JAK2 and STAT3 via the allosteric sites of PGAM1, which leads to inactivation of JAK2/STAT3 and thereby disrupts IL-6/JAK2/STAT3 signaling pathway. Consequently, HKB99 remarkably restores EGFR inhibitor sensitivity and exerts synergistic tumoricidal effect. Additionally, HKB99 alone or in combination with osimertinib down-regulated the level of p-STAT3 in xenograft tumor models. Collectively, this study identifies PGAM1 as a key regulator in IL-6/JAK2/STAT3 axis in the development of resistance to EGFR inhibitors, which could serve as a therapeutic target in lung adenocarcinoma with acquired resistance to EGFR inhibitors.

Frontier of toxicology studies in zebrafish model.

Based on the 87 original publications only from quartiles 1 and 2 of Journal Citation Report (JCR) collected by the major academic databases (Science Direct, Web of Science, PubMed, and Wiley) in 2022, the frontier of toxicology studies in zebrafish model is summarized. Herewith, a total of six aspects is covered such as developmental, neurological, cardiovascular, hepatic, reproductive, and immunizing toxicities. The tested samples involve chemicals, drugs, new environmental pollutants, nanomaterials, and its derivatives, along with those related mechanisms. This report may provide a frontier focus benefit to researchers engaging in a zebrafish model for environment, medicine, food, and other fields.

TIA1 potentiates tau phase separation and promotes generation of toxic oligomeric tau.

Tau protein plays an important role in the biology of stress granules and in the stress response of neurons, but the nature of these biochemical interactions is not known. Here we show that the interaction of tau with RNA and the RNA binding protein TIA1 is sufficient to drive phase separation of tau at physiological concentrations, without the requirement for artificial crowding agents such as polyethylene glycol (PEG). We further show that phase separation of tau in the presence of RNA and TIA1 generates abundant tau oligomers. Prior studies indicate that recombinant tau readily forms oligomers and fibrils in vitro in the presence of polyanionic agents, including RNA, but the resulting tau aggregates are not particularly toxic. We discover that tau oligomers generated during copartitioning with TIA1 are significantly more toxic than tau aggregates generated by incubation with RNA alone or phase-separated tau complexes generated by incubation with artificial crowding agents. This pathway identifies a potentially important source for generation of toxic tau oligomers in tau-related neurodegenerative diseases. Our results also reveal a general principle that phase-separated RBP droplets provide a vehicle for coassortment of selected proteins. Tau selectively copartitions with TIA1 under physiological conditions, emphasizing the importance of TIA1 for tau biology. Other RBPs, such as G3BP1, are able to copartition with tau, but this happens only in the presence of crowding agents. This type of selective mixing might provide a basis through which membraneless organelles bring together functionally relevant proteins to promote particular biological activities.

ABPP-CoDEL: Activity-Based Proteome Profiling-Guided Discovery of Tyrosine-Targeting Covalent Inhibitors from DNA-Encoded Libraries.

DNA-encoded chemical library (DEL) has been extensively used for lead compound discovery for decades in academia and industry. Incorporating an electrophile warhead into DNA-encoded compounds recently permitted the discovery of covalent ligands that selectively react with a particular cysteine residue. However, noncysteine residues remain underexplored as modification sites of covalent DELs. Herein, we report the design and utility of tyrosine-targeting DELs of 67 million compounds. Proteome-wide reactivity analysis of tyrosine-reactive sulfonyl fluoride (SF) covalent probes suggested three enzymes (phosphoglycerate mutase 1, glutathione s-transferase 1, and dipeptidyl peptidase 3) as models of tyrosine-targetable proteins. Enrichment with SF-functionalized DELs led to the identification of a series of tyrosine-targeting covalent inhibitors of the model enzymes. In-depth mechanistic investigation revealed their novel modes of action and reactive ligand-accessible hotspots of the enzymes. Our strategy of combining activity-based proteome profiling and covalent DEL enrichment (ABPP-CoDEL), which generated selective covalent binders against a variety of target proteins, illustrates the potential use of this methodology in further covalent drug discovery.

Interface Regulation for Efficient and Stable Perovskite Solar Cells through Potassium Citrate Molecules.

Efficiency and stability are key factors determining the final cost of electricity that perovskite solar cells (PSCs) generate. To date, effective strategy to progress in achieving efficient and stable PSCs is still a difficult problem that researchers continue to explore. This study reports a useful way to improve the quality of SnO2 film by introducing potassium citrate (PC) into SnO2 nanoparticles solution. PC passivates interface defects between perovskite and SnO2 layers via the interactions of functional groups (K+ , -COO- ) in PC with undersaturated Pb and I ions in perovskite and Sn4+ in SnO2 . The resultant photovoltaic (PV) device achieves a champion power conversion efficiency (PCE) of 22.79 %. The introduction of PC interface also significantly suppress the degradation of PSCs, by which 87.6 % of initial PCE is maintained after 2850 h storage in ambient environment. Moreover, the devices retained 95.5 % of initial PCE under 1-sun continuous illumination for 1000 h.

Electrochemical Detection of Flutamide by the Composite of Complex Based on Thiacalix[4]arene Derivatives and Reduced Graphene Oxide.

In this paper, a thiacalix[4]arene complex [Zn2(TIT4A)L2]·4DMF·2CH3OH (H2L = 4,4'-oxybisbenzoic acid) (Zn-TIT4A-L) was synthesized by a solvothermal method. The composites were prepared by combining Zn-TIT4A-L with reduced graphene oxide (RGO), mesoporous carbon (MC), and multi-walled carbon nanotubes (MWCNTs), respectively. Three representative composites are Zn-TIT4A-L@RGO(1:1), Zn-TIT4A-L@MC(1:2), and Zn-TIT4A-L@MWCNT(1:2). X-ray diffraction and scanning electron microscopy characterized their structures and morphologies. The results showed that three composites were successfully prepared, and the crystals of the complex remained in the composites. The electrochemical properties of the composites were characterized by electrochemical impedance spectroscopy and cyclic voltammetry. The results indicated that they had good electrocatalytic activity and conductivity. Among them, Zn-TIT4A-L@RGO(1:1) had the best performance and was used for the quantitative detection of flutamide (FTA). The linear range of detection is 0.1-200 µM, and the limit of detection is 0.015 µM. At the same time, the sensor also had good reproducibility, anti-interference, and stability. The sensor was also used for the detection of FTA in lake water, human urine, and serum with a satisfactory recovery rate. The possible mechanism of electrochemical detection of FTA was also discussed.

Pseudoaneurysm of the mitral-aortic intervalvular fibrosa: a rare case after percutaneous transluminal coronary angioplasty.

BACKGROUND: Pseudoaneurysm of the mitral-aortic intervalvular fibrosa (P-MAIVF) is an uncommon but potentially life-threatening condition. The most common pathogenic factors of P-MAIVF are infective endocarditis and surgical valve operation. Here, we report a rare case of P-MAIVF which occurred one year after percutaneous transluminal coronary angioplasty (PTCA). CASE PRESENTATION: A 31-year-old man developed a P-MAIVF one year after PTCA. Transthoracic echocardiography (TTE) revealed a pseudoaneurysm between the aortic root and the left atrium. Three-dimensional transesophageal echocardiography (3D-TEE) clearly demonstrated the orifice of the pseudoaneurysm. This case was initially diagnosed by ultrasound, and the prognosis was good after surgical repair. CONCLUSIONS: We report a rare case of P-MAIVF that occurred one year after PTCA.

Analysis of Mechanism of Action of Cuprous Oxide Nanoparticles in Treatment of Cervical Cancer under Real-time Ultrasound Elastography.

It aimed to explore the adoption value of cuprous oxide nanoparticles (Cu2O NPs) in the clinical treatment of cervical cancer under the evaluation of real-time ultrasound elastography. In this experiment, the solution of Cu2O NPs was synthesized and used in 90 selected mouse models of cervical cancer. It was found that Cu2O NPs can significantly control the reproduction of various types of cervical cancer cells, effectively stopping the cycle of cervical cancer cell lines in the G1/G0 phase. In addition, the tumor weight of 0.25g in the Cu2O NPs group was notably lighter than that of 1.1g in the control group. The weight change of the mouse was 21g compared with 15g of the cis-dichlorodiamine platinum (CDDP) group, and it was proved that Cu2O NPs were less cytotoxic to the body and have few side effects. Moreover, real-time ultrasound elastography showed that there were 26 cases with a tumor elasticity score no less than 2 in the Cu2O NPs group, accounting for 87%, which was better than that of the CDDP group (17 cases, 57%), and the difference was substantial (P<0.05). The shear wave velocity of Cu2O NPs (1.46±0.48 m/s) was also lower than that (1.73±0.62 m/s) of the CDDP group, which suggested that the tumor body hardness of mice in the Cu2O NPs group was lower, and the difference was considerable (P<0.05). In short, Cu2O NPs had good functions such as inhibiting the proliferation and spread of tumor cells and blocking the cell cycle. Moreover, the toxic and side effects of the drug were slight, and it was an ideal new type of treatment for cervical cancer.

An allosteric PGAM1 inhibitor effectively suppresses pancreatic ductal adenocarcinoma.

Glycolytic enzyme phosphoglycerate mutase 1 (PGAM1) plays a critical role in cancer metabolism by coordinating glycolysis and biosynthesis. A well-validated PGAM1 inhibitor, however, has not been reported for treating pancreatic ductal adenocarcinoma (PDAC), which is one of the deadliest malignancies worldwide. By uncovering the elevated PGAM1 expressions were statistically related to worse prognosis of PDAC in a cohort of 50 patients, we developed a series of allosteric PGAM1 inhibitors by structure-guided optimization. The compound KH3 significantly suppressed proliferation of various PDAC cells by down-regulating the levels of glycolysis and mitochondrial respiration in correlation with PGAM1 expression. Similar to PGAM1 depletion, KH3 dramatically hampered the canonic pathways highly involved in cancer metabolism and development. Additionally, we observed the shared expression profiles of several signature pathways at 12 h after treatment in multiple PDAC primary cells of which the matched patient-derived xenograft (PDX) models responded similarly to KH3 in the 2 wk treatment. The better responses to KH3 in PDXs were associated with higher expression of PGAM1 and longer/stronger suppressions of cancer metabolic pathways. Taken together, our findings demonstrate a strategy of targeting cancer metabolism by PGAM1 inhibition in PDAC. Also, this work provided "proof of concept" for the potential application of metabolic treatment in clinical practice.

Mechanosensitive Piezo1 channel activation promotes ventilator-induced lung injury via disruption of endothelial junctions in ARDS rats.

OBJECTIVE: This study aimed to investigate the role of endothelial Piezo1 in mediating ventilator-induced lung injury secondary to acute respiratory distress syndrome (ARDS). METHODS: Rats and lung endothelial cells (ECs) were transfected with Piezo1 shRNA (shPiezo1) and Piezo1 siRNA, respectively, to knock down Piezo1. Intratracheal instillation or incubation with lipopolysaccharide (LPS) was used to establish an ARDS model, and high tidal volume (HVT) ventilation or 20% cyclic stretch (CS) was administered to simulate a two-hit injury. Lung injury, alterations in lung endothelial barrier, disruption of adherens junctions (AJs), and Ca2+ influx were assessed. RESULTS: Lung vascular hyperpermeability was further increased in ARDS rats following HVT ventilation, which was abrogated in shPiezo1-treated rats. 20% CS led to severer rupture of AJs following LPS stimulation as indicated by immunofluorescence staining. The internalization and degradation of VE-cadherin were blocked by knockdown of Piezo1. Additionally, 20% CS induced Piezo1 activation, manifesting as elevated intracellular Ca2+ concentration in LPS-treated ECs, and subsequently increased calcium-dependent calpain activity. Pharmacological inhibition of calpain or Piezo1 knockdown prevented the loss of VE-cadherin, p120-catenin, and ß-catenin in ARDS rats undergoing HVT ventilation and LPS-treated ECs exposed to 20% CS. CONCLUSION: Excessive mechanical stretch during ARDS induces the activation of Piezo1 channel and its downstream target, calpain, via Ca2+ influx. This results in the disassembly of endothelial AJs and further facilitates lung endothelial barrier breakdown and vascular hyperpermeability.

Mechanosensitive cation channel Piezo1 contributes to ventilator-induced lung injury by activating RhoA/ROCK1 in rats.

BACKGROUND: Mechanical ventilation can induce or aggravate lung injury, which is termed ventilator-induced lung injury (VILI). Piezo1 is a key element of the mechanotransduction process and can transduce mechanical signals into biological signals by mediating Ca2+ influx, which in turn regulates cytoskeletal remodeling and stress alterations. We hypothesized that it plays an important role in the occurrence of VILI, and investigated the underlying mechanisms. METHODS: High tidal volume mechanical ventilation and high magnitude cyclic stretch were performed on Sprague-Dawley rats, and A549 and human pulmonary microvascular endothelial cells, respectively, to establish VILI models. Immunohistochemical staining, flow cytometry, histological examination, enzyme-linked immunosorbent assay, western blotting, quantitative real-time polymerase chain reaction and survival curves were used to assess the effect of Piezo1 on induction of lung injury, as well as the signaling pathways involved. RESULTS: We observed that Piezo1 expression increased in the lungs after high tidal volume mechanical ventilation and in cyclic stretch-treated cells. Mechanistically, we observed the enhanced expression of RhoA/ROCK1 in both cyclic stretch and Yoda1-treated cells, while the deficiency or inhibition of Piezo1 dramatically antagonized RhoA/ROCK1 expression. Furthermore, blockade of RhoA/ROCK1 signaling using an inhibitor did not affect Piezo1 expression. GSMTx4 was used to inhibit Piezo1, which alleviated VILI-induced pathologic changes, water content and protein leakage in the lungs, and the induction of systemic inflammatory mediators, and improved the 7-day mortality rate in the model rats. CONCLUSIONS: These findings indicate that Piezo1 affects the development and progression of VILI through promotion of RhoA/ROCK1 signaling.

Design, synthesis, and biological evaluation of 1,3,6,7-tetrahydroxyxanthone derivatives as phosphoglycerate mutase 1 inhibitors.

Phosphoglycerate mutase 1 (PGAM1) is a promising target for cancer treatment. Herein, we found that α-mangostin and γ-mangostin exhibited moderate PGAM1 inhibitory activities, with IC50 of 7.2 µM and 1.2 µM, respectively. Based on α-mangostin, a series of 1,3,6,7-tetrahydroxyxanthone derivatives were designed, synthesized and evaluated in vitro for PGAM1 inhibition. The significant structure-activity relationships (SAR) and a fresh binding mode of this kind of new compounds were also clearly described. This study provides valuable information for further optimization of PGAM1 inhibitors with 1,3,6,7-tetrahydroxyxanthone backbone or de novo design of novel inhibitor.

Effects of intraoperative lung-protective ventilation on clinical outcomes in patients with traumatic brain injury: a randomized controlled trial.

BACKGROUND: Secondary lung injury is the most common non-neurological complication after traumatic brain injury (TBI). Lung-protective ventilation (LPV) has been proven to improve perioperative oxygenation and lung compliance in some critical patients. This study aimed to investigate whether intraoperative LPV could improve respiratory function and prevent postoperative complications in emergency TBI patients. METHODS: Ninety TBI patients were randomly allocated to three groups (1:1:1): Group A, conventional mechanical ventilation [tidal volume (VT) 10 mL/kg only]; Group B, small VT (8 mL/kg) + positive end-expiratory pressure (PEEP) (5 cmH2O); and Group C, small VT (8 mL/kg) + PEEP (5 cmH2O) + recruitment maneuvers (RMs). The primary outcome was the incidence of total postoperative pulmonary complications; Secondary outcomes were intraoperative respiratory mechanics parameters and serum levels of brain injury markers, and the incidence of each postoperative pulmonary and neurological complication. RESULTS: Seventy-nine patients completed the final analysis. The intraoperative PaO2 and dynamic pulmonary compliance of Groups B and C were higher than those of Group A (P = 0.028; P = 0.005), while their airway peak pressure and plateau pressure were lower than those of group A (P = 0.004; P = 0.005). Compared to Group A, Groups B and C had decreased 30-day postoperative incidences of total pulmonary complications, hypoxemia, pulmonary infection, and atelectasis (84.0 % vs. 57.1 % vs. 53.8 %, P = 0.047; 52.0 % vs. 14.3 % vs. 19.2 %, P = 0.005; 84.0 % vs. 50.0 % vs. 42.3 %, P = 0.006; 24.0 % vs. 3.6 % vs. 0.0 %, P = 0.004). Moreover, intraoperative hypotension was more frequent in Group C than in Groups A and B (P = 0.007). At the end of surgery, the serum levels of glial fibrillary acidic protein and ubiquitin carboxyl-terminal hydrolase isozyme L1 in Group B were lower than those in Groups A and C (P = 0.002; P < 0.001). The postoperative incidences of neurological complications among the three groups were comparable. CONCLUSIONS: Continuous intraoperative administration of small VT + PEEP is beneficial to TBI patients. Additional RMs can be performed with caution to prevent disturbances in the stability of cerebral hemodynamics. TRIAL REGISTRATION: Chinese Clinical Trial Registry (ChiCTR2000038314), retrospectively registered on September 17, 2020.

An psychoeducation programme based on self-efficacy theory to improve experience of natural birth for primigravid women: Study protocol for a randomised controlled trial.

AIM AND OBJECTIVES: To present a study protocol for estimating the feasibility, effectiveness and safety of an individual (five sessions), group (one session) and face-to-face psychoeducation programme based on self-efficacy theory to improve childbirth experience of primigravid women. BACKGROUND: In present China, fertility rates are falling and ageing is accelerating. How to improve the fertility level of childbearing women is of great significance. However, about 10%-20% of women have negative childbirth experience after birth, which seriously affects maternal and child health and family functions, and even fertility desires and intentions in the future. Nevertheless, due to the lack of a series of well-designed randomised controlled trials(RCTs), there is no specific methodology to guide the most effective intervention for primigravid women. In this regard, based on Bandura's self-efficacy theory, an intervention programme to promote a positive childbirth experience for primigravid women has been designed and will be evaluated to determine its impact on primigravid women. DESIGN: A non-blinded randomised controlled trial. METHODS: We report the study protocol for this randomised controlled trial based on the SPIRIT2013 statement. A total of 238 eligible primigravid women will be randomly divided into the control group (n = 119) or the intervention group (n = 119). The control group will receive care as usual, that is, six routine prenatal examinations. In addition to the routine examinations, the intervention group will also receive six face-to-face interventions. Baseline assessment will occur at about 24th week of gestation and follow up at 37th weeks of gestation, intrapartum, 1-3 days postpartum and 42 days postpartum. The primary outcomes are childbirth experience, childbirth self-efficacy; others are fear of childbirth, labour control, labour pain and labour satisfaction. IMPACT: From the perspective of clinical work, this protocol provides practical guidance for cultivating the positive childbirth experience of the primigravid women. From the perspective of sociology, the positive experience and emotion of primigravid women can improve the fertility intention of women of childbearing age, which is relatively conducive to optimising Chinese demographic structure and reducing the pressure of ageing population in the long term.

Heteroexpression and biochemical characterization of thermostable citrate synthase from the cyanobacteria Anabaena sp. PCC7120.

The present study recombinantly expressed a citrate synthase from cyanobacteria Anabaena sp. PCC7120 (AnCS) in Escherichia coli and characterized its enzymatic activity. The molecular mass of native AnCS was 88,533.1 Da containing two 44,162.7 Da subunits. Recombinant AnCS revealed the highest activity at pH 9.0 and 25 °C. AnCS displayed high thermal stability with a half-life time (t1/2) of approximately 6.5 h at 60 °C, which was more thermostable than most CS from general organisms, but less than those from hyperthermophilic bacteria. The Km values of oxaloacetate and acetyl-CoA were 138.50 and 18.15 µM respectively, suggesting a higher affinity to acetyl-CoA than oxaloacetate. Our inhibition assays showed that AnCS activity was not severely affected by most metal ions, but was strongly inhibited by Cu2+ and Zn2+. Treatments with ATP, ADP, AMP, NADH, and DTT depressed the AnCS activity. Overall, our results provide information on the enzymatic properties of AnCS, which contributes to the basic knowledge on CS selection for industrial utilizations.