Selective Construction and Structural Transformation of Homogeneous Linear Metalla[4]catenane and Metalla[2]catenane Assemblies.

Although the synthesis of mechanically interlocked molecules has been extensively researched, selectively constructing homogeneous linear [4]catenanes remains a formidable challenge. Here, we selectively constructed a homogeneous linear metalla[4]catenane in a one-step process through the coordination-driven self-assembly of a bidentate benzothiadiazole derivative ligand and a binuclear half-sandwich rhodium precursor. The formation of metalla[4]catenanes was facilitated by cooperative interactions between strong sandwich-type π-π stacking and non-classical hydrogen bonds between the components. Moreover, by modulating the aromatic substituents on the binuclear precursor, two homogeneous metalla[2]catenanes were obtained. The molecular structures of these metallacatenanes were unambiguously characterized by single-crystal X-ray diffraction analysis. Additionally, reversible structural transformation between metal-catenanes and the corresponding metallarectangles could be achieved by altering their concentration, as confirmed by mass spectrometry and NMR spectroscopy studies.

Ultrasound-guided fascia iliaca compartment block for pain control in total hip arthroplasty: A systematic review and meta-analysis.

BACKGROUND: Previous studies have investigated the effectiveness and safety of ultrasound-guided fascia iliaca compartment block (UGFICB) compared to quadratus lumborum block (QLB) for pain management in total hip arthroplasty (THA). However, there is currently a lack of a systematic review specifically addressing this issue. Therefore, the purpose of this study was to conduct a comprehensive analysis and comparison of the efficacy and safety of UGFICB versus QLB for pain management in THA. METHODS: An extensive search was conducted in various electronic databases, including PUBMED, EMBASE, Cochrane Library, Web of Science, Scopus, China Biomedical Literature Service System, and China National Knowledge Infrastructure. This search encompassed all relevant studies published from the inception of these databases until June 30, 2023. The selected outcomes for analysis included moving and resting visual analogue scale (VAS) scores at 12 hours and 24 hours post-surgery, as well as opioids consumption at 24 hours post-surgery. The Cochrane risk-of-bias tool was utilized to assess the risk of bias in the trials included in the analysis. Statistical analysis was conducted using RevMan 5.4 software. RESULTS: A total of 8 trials, involving 656 patients, were included in this study. The results of the meta-analysis showed no significant differences between the 2 modalities in terms of moving VAS scores (mean difference [MD] = 0.17, 95% confidence interval [CI] [-0.79, 1.14], P = .72) and resting VAS scores (MD = 0.04, 95% CI [-0.27, 0.36], P = .78) at 12 hours post-surgery, and moving VAS scores (MD = 0.27, 95% CI [-0.46, 1.01], P = .47) and resting VAS scores (MD = -0.05, 95% CI [-0.45, 0.35], P = .80) at 24 hours post-surgery. However, there was significant differences in opioids consumption at 24 hours post-surgery (MD = 8.98, 95% CI [2.04, 15.93], P = .01) between the 2 groups. CONCLUSION: Based on these findings, the study concludes that UGFICB may be more beneficial than QLB for pain management in THA. However, it is important to interpret these results with caution due to certain limitations.

S1PR1 regulates ovarian cancer cell senescence through the PDK1-LATS1/2-YAP pathway.

Cell senescence deters the activation of various oncogenes. Induction of senescence is, therefore, a potentially effective strategy to interfere with vital processes in tumor cells. Sphingosine-1-phosphate receptor 1 (S1PR1) has been implicated in various cancer types, including ovarian cancer. The mechanism by which S1PR1 regulates ovarian cancer cell senescence is currently elusive. In this study, we demonstrate that S1PR1 was highly expressed in human ovarian cancer tissues and cell lines. S1PR1 deletion inhibited the proliferation and migration of ovarian cancer cells. S1PR1 deletion promoted ovarian cancer cell senescence and sensitized ovarian cancer cells to cisplatin chemotherapy. Exposure of ovarian cancer cells to sphingosine-1-phosphate (S1P) increased the expression of 3-phosphatidylinositol-dependent protein kinase 1 (PDK1), decreased the expression of large tumor suppressor 1/2 (LATS1/2), and induced phosphorylation of Yes-associated protein (p-YAP). Opposite results were obtained in S1PR1 knockout cells following pharmacological inhibition. After silencing LATS1/2 in S1PR1-deficient ovarian cancer cells, senescence was suppressed and S1PR1 expression was increased concomitantly with YAP expression. Transcriptional regulation of S1PR1 by YAP was confirmed by chromatin immunoprecipitation. Accordingly, the S1PR1-PDK1-LATS1/2-YAP pathway regulates ovarian cancer cell senescence and does so through a YAP-mediated feedback loop. S1PR1 constitutes a druggable target for the induction of senescence in ovarian cancer cells. Pharmacological intervention in the S1PR1-PDK1-LATS1/2-YAP signaling axis may augment the efficacy of standard chemotherapy.

Development of a high-affinity anti-bovine PD-1 rabbit-bovine chimeric antibody using an efficient selection and large production system.

Immune checkpoint molecules PD-1/PD-L1 cause T-cell exhaustion and contribute to disease progression in chronic infections of cattle. We established monoclonal antibodies (mAbs) that specifically inhibit the binding of bovine PD-1/PD-L1; however, conventional anti-PD-1 mAbs are not suitable as therapeutic agents because of their low binding affinity to antigen. In addition, their sensitivity for the detection of bovine PD-1 is low and their use for immunostaining PD-1 is limited. To address these issues, we established two anti-bovine PD-1 rabbit mAbs (1F10F1 and 4F5F2) and its chimeric form using bovine IgG1 (Boch1D10F1), which exhibit high binding affinity. One of the rabbit mAb 1D10F1 binds more strongly to bovine PD-1 compared with a conventional anti-PD-1 mAb (5D2) and exhibits marked inhibitory activity on the PD-1/PD-L1 interaction. In addition, PD-1 expression in bovine T cells could be detected with higher sensitivity by flow cytometry using 1D10F1. Furthermore, we established higher-producing cells of Boch1D10F1 and succeeded in the mass production of Boch1D10F1. Boch1D10F1 exhibited a similar binding affinity to bovine PD-1 and the inhibitory activity on PD-1/PD-L1 binding compared with 1D10F1. The immune activation by Boch1D10F1 was also confirmed by the enhancement of IFN-γ production. Finally, Boch1D10F1 was administered to bovine leukemia virus-infected cows to determine its antiviral effect. In conclusion, the high-affinity anti-PD-1 antibody developed in this study represents a powerful tool for detecting and inhibiting bovine PD-1 and is a candidate for PD-1-targeted immunotherapy in cattle.

GPX4 inhibition synergistically boosts mitochondria targeting nanoartemisinin-induced apoptosis/ferroptosis combination cancer therapy.

Artemisinin, originally used for its antimalarial activity, has received much attention in recent years for cancer therapy. The anticancer mechanisms of artemisinin are complicated and debatable. Challenges in the delivery of artemisinin also persist because the anticancer effect of artemisinin alone is often not satisfactory when used with traditional nanocarriers. We herein report the mitochondrial delivery of artemisinin with extremely high anticancer capacity. The action mode of artemisinin in the mitochondria of cancer cells includes heme-participating and oxygen-independent conversion of artemisinin into a carbon-centered radical, which is partly converted into ROS in the presence of molecular oxygen. We reveal that artemisinin alone in the mitochondria can induce strong cancer cell apoptosis. In addition, due to the weak inhibition of GPX4 activity by artemisinin, weak ferroptosis is also observed. We further discover that GPX4 activity in MCF-7 cells is greatly inhibited by RSL3 to synergistically enhance the anticancer capacity of artemisinin via enhancing ferroptosis. The synergistic anticancer activity of artemisinin and RSL3 in the mitochondria not only improves cancer cell-killing ability, but also inhibits the re-proliferation of residual cancer cells. This study provides a new insight into developing highly efficient and practical artemisinin nanomedicines for cancer therapy.

K2CO3/18-Crown-6-Catalyzed Selective H/D Exchange of Heteroarenes with Bromide as a Removable Directing Group.

The K2CO3/18-crown-6-catalyzed H/D exchange of heretoarenes in high atom % deuterium incorporation is disclosed. The use of a weak base as a catalyst leads to excellent site selectivity and broad functional group tolerance. Control experiments indicated that the use of bromide, which enhances the adjacent C-H bond reactivity, as a removable directing group is essential. Moreover, conversion of bromide to other functional groups is also performed to construct other useful deuterated compounds.

Development and performance evaluations of an HER-2 kit.

Objective To develop a kit for detecting human epidermal growth factor receptor 2 (HER-2) in the human body. Methods The HER-2 kit was evaluated based on an automated magnetic particle chemiluminescence platform. The kit was developed using the double antibody sandwich-complexation method. Results The kit showed a linear range of 0.01-800 ng/mL, with a linear R2 of >0.999. The limit of the blank was 0.0039 ng/mL, and the precision at 1.00 ng/mL was 9.4%. The recovery rate at 10.00 ng/mL was 97.81-101.81%. The negative serum reference range was 0-8.23 ng/mL. Conclusions The kit had a wide linear range, high accuracy, good precision, and high sensitivity, indicating that it has good application prospects.

Preparation and characterization of carboxymethyl chitosan/pullulan composite film incorporated with eugenol and its application in the preservation of chilled meat.

To solve the problem of easy spoilage of chilled meat during storage, we fabricated a novel composite film using carboxymethyl chitosan (CMCS)/pullulan (Pul)/eugenol (E) by casting method. The results showed that the mechanical properties of the films were better when the CMCS/Pul ratio was 2.5/2.5. The Fourier transform infrared spectroscopy (FTIR) results showed that intermolecular hydrogen bonds were formed among E, CMCS, and Pul, which was consistent with the rheological test results. Scanning electron microscopic (SEM) images showed that eugenol was well dispersed in the CMCS/Pul matrix. The addition of eugenol significantly increased the antibacterial properties and antioxidant properties. Moreover, when 5% eugenol was added, the water vapor permeability (WVP) of the film reduced to 2.41 × 10-11 g/m·s·Pa. Finally, the freshness of the chilled meat wrapped with the eugenol-containing composite film was prolonged, thereby offering a potential alternative to synthetic materials.

Medicine for chronic atrophic gastritis: a systematic review, meta- and network pharmacology analysis.

PURPOSE: The aim of this study is to determine the effectiveness and reliability of adding traditional Chinese medicine (TCM) in the clinical intervention and explore mechanisms of action for chronic atrophic gastritis (CAG) through meta- and network pharmacology analysis (NPAs). METHODS: A predefined search strategy was used to retrieve literature from PubMed, Embase database, Cochrane Library, China National Knowledge Infrastructure (CNKI), Chinese BioMedical Literature Database (CBM), Wan Fang Data and China Science and Technology Journal Database (VIP). After applying inclusion and exclusion criteria, a total of 12 randomized controlled trials (RCTs) were included for meta-analysis to provide clinical evidence of the intervention effects. A network meta-analysis using Bayesian networks was conducted to observe the relative effects of different intervention measures and possible ranking of effects. The composition of the TCM formulation in the experimental group was analysed, and association rule mining was performed to identify hub herbal medicines. Target genes for CAG were searched in GeneCards, Online Mendelian Inheritance in Man, PharmGKB, Therapeutic Target Database and DrugBank. A regulatory network was constructed to connect the target genes with active ingredients of the hub herbal medicines. Enrichment analyses were performed using the Gene Ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG) to examine the central targets from a comprehensive viewpoint. Protein-protein interaction networks (PPINs) were constructed to identify hub genes and conduct molecular docking with differentially expressed genes (DEGs) and corresponding active molecules. RESULTS: A total of 1140 participants from 12 RCTs were included in the statistical analysis, confirming that the experimental group receiving the addition of TCM intervention had better clinical efficacy. Seven hub TCMs (Paeonia lactiflora, Atractylodes macrocephala, Pinellia ternata, Citrus reticulata, Codonopsis pilosula, Salvia miltiorrhiza and Coptis chinensis) were identified through association rule analysis of all included TCMs. Thirteen hub genes (CDKN1A, CASP3, STAT1, TP53, JUN, MAPK1, STAT3, MAPK3, MYC, HIF1A, FOS, MAPK14 and AKT1) were obtained from 90 gene PPINs. Differential gene expression analysis between the disease and normal gastric tissue identified MAPK1 and MAPK3 as the significant genes. Molecular docking analysis revealed that naringenin, luteolin and quercetin were the main active compounds with good binding activities to the two hub targets. GO analysis demonstrated the function of the targets in protein binding, while KEGG analysis indicated their involvement in important pathways related to cancer. CONCLUSIONS: The results of a meta-analysis of 12 RCTs indicate that TCM intervention can improve the clinical treatment efficacy of CAG. NPAs identified seven hub TCM and 13 target genes associated with their actions, while bioinformatics analysis identified two DEGs between normal and CAG gastric tissues. Finally, molecular docking was employed to reveal the mechanism of action of the active molecules in TCM on the DEGs. These findings not only reveal the mechanisms of action of the active components of the TCMs, but also provide support for the development of new drugs, ultimately blocking the progression from chronic gastritis to gastric cancer.

[Preparation of monoclonal antibodies against Pinellia ternata lectin protein and establishment of double-antibody sandwich ELISA].

To determine the content of endogenous toxic substance Pinellia ternata lectin(PTL) protein in Pinelliae Rhizoma and the related processed products, this study prepared specific monoclonal antibodies against PTL by hybridoma cell technology, and established a quantitative double-antibody sandwich enzyme linked immunosorbent assay(ELISA) for PTL antigen. The detection conditions were 2.5 µg·mL~(-1) working concentration of the captured antibody and 1∶450 of the dilution multiple of detected antibody. The coating condition was staying overnight at 4 ℃. The blocking time and incubation times of antigen and detected antibody were all 90 minutes. The incubation time of horseradish peroxidase conjugated streptavidin-horseradish peroxidase(SA-HRP) was 15 minutes. The quantitative limit of the method for PTL antigen was 0.375 ng·mL~(-1). The linear range was 75.000-4 800.000 pg·mL~(-1), and R~2=0.997 1. The recovery rate was 90.0%-110.0%, and the variation coefficients of intra-test and inter-test precision were 2.0%-3.0% and 2.0%-8.5%.The content of PTL in three batches of Pinelliae Rhizoma and the related processed products was determined by the method, and the average content of PTL in Pinelliae Rhizoma was 35.42 mg·g~(-1). The average content of PTL in Pinelliae Rhizoma Praeparatum Cum Alumine, Pinelliae Rhizoma Praeparatum, and Pinelliae Rhizoma Praeparatum Cum Zingibere Et Alumine were 1.15 mg·g~(-1), 16.53 µg·g~(-1), and 122.63 ng·g~(-1), respectively, indicating that the content of PTL decreased significantly after processing. The quantitative double-antibody sandwich ELISA for PTL antigen established in this paper had good linearity, sensitive response, and high accuracy, which provided a simple and effective monitoring method for the detection of PTL content in the processing of Pinelliae Rhizoma.

[Anti-ascites effect of total saponins of Phytolaccae Radix on mice with ascites and mechanism].

This study investigated the anti-ascites effect of the total saponins of Phytolaccae Radix(PRTS) and the mechanism.H22 cell suspension was used(ip) to induce ascites in ICR male mice, and the model mice were randomized into model group, positive drug group(furosemide, 6 mg·kg~(-1)), total extract of Phytolaccae Radix(PRTE) group, and PRTS(1.29 g·kg~(-1)).Another 10 male mice were selected as the blank group.Mice in the blank group and model group were given(ig) normal saline containing 0.5% CMC-Na, and those in the positive drug group, PRTE group, and PRTS group received(ig) corresponding doses of drugs, once a day, for 8 consecutive days.The ascites volume, urine volume, and fecal water content in mice with ascites, serum levels of antidiure-tic hormone(ADH), renin in renin-angiotensin-aldosterone system(RAAS), angiotensin Ⅱ(AngⅡ), and aldosterone(ALD), expression of aquaporin(AQP)1-AQP4 in kidney, expression of AQP1, AQP3 in colon, and expression of phosphatidylinositol 3-kinase/protein kinase B(PI3 K/Akt) pathway-related proteins were detected to explore the anti-ascites mechanism of PRTS.The results showed that the PRTS can increase the urine volume and fecal water content and decrease the ascites volume of ascites mice.Moreover, PRTS significantly reduced the expression of AQP1-AQP4 in kidney and AQP1, AQP3 in colon, serum levels of renin, AngⅡ, ALD, and ADH, and the expression of p-PI3 K and p-Akt in the kidney of ascites mice.PRTS exerts anti-ascites effect by promoting urination and defecation.The mechanism is that it inhibits the activities of RAAS and ADH and suppresses the phosphorylation of PI3 K/Akt signaling pathway, thereby restricting the expression of AQPs in the kidney and colon.

[Irritant toxicity and lectin content of different processed products of Pinelliae Rhizoma].

The present study aims to investigate the correlation between irritant toxicity variation and lectin content variation during the processing of Pinelliae Rhizoma products and to explore the feasibility of Western blot as a method for the detection of lectin. We processed Pinelliae Rhizoma Praeparatum Cum Alumine, Pinelliae Rhizoma Praeparatum, and Pinelliae Rhizoma Praeparatumcum Zingibere et Alumine to different degrees and then analyzed their irritant toxicity via Draize rabbit eye test. Western blot was employed to determine the lectin content in Pinelliae Rhizoma products processed with different methods. The correlation between toxicity variation and lectin content variation was then analyzed. Different decoction pieces of Pinelliae Rhizoma were collected for the determination of lectin content. The three processed products of Pinelliae Rhizoma showed gradually decreased toxicity and lectin content as the processing continued. The decreasing trend of lectin content was consistent with that of irritant toxicity during processing, which indicated that the change in lectin content could reflect the trend of irritant toxicity. No band of lectin appeared in the Western blot of processed products of Pinelliae Rhizoma, which suggested that western blotting can be used for the detection of toxic lectin in the processed products of Pinelliae Rhizoma. Lectin should not be detected in the Pinelliae Rhizoma products processed according to the methods in the Chinese Pharmacopoeia.

The relationship between physical activity and prosocial behavior of college students: A mediating role of self-perception.

OBJECTIVE: To explore the relationship between physical activity and prosocial behavior in college students, and to examine whether self-perception and gender may play mediating and moderating roles, respectively, in that relationship. METHODS: The International Physical Activity Questionnaire-long form, Prosocial Tendencies Measure, and Self-perception Scale were used to survey 647 college students in Yangzhou, China. Internal consistency testing, one-way analyses of variance (ANOVAs) across physical activity levels, exploratory factor analysis, correlation testing, mediation effect testing (independent variable, physical activity; mediating variable, self-perception; dependent variable, prosocial behavior), bootstrap testing and moderated mediation testing were conducted. RESULTS: Physical activity level was not found to be a direct predictor prosocial behavior in college students. Self-perception was found to play a mediating role between physical activity and prosocial behavior. CONCLUSION: Physical activity is not directly predictive college students' prosocial behavior tendencies, but it is indirectly predictive through self-perception. This study explores the relationship between the three variables and the path of the relationship, deepening the research related to the relationship between physical activity and prosocial behavior, providing ideas for fostering prosocial behavior in Chinese universities, as well as providing a theoretical basis for possible future empirical research.

Effects of fascia iliaca compartment block as an adjunctive management to parecoxib for pain control after total hip arthroplasty.

BACKGROUND: This retrospective study investigated the effects of fascia iliaca compartment block (FICB) as an adjunctive management to parecoxib for pain control after total hip arthroplasty (THA). METHODS: A total of 72 patient records of THA were included in this retrospective study. All patients received parecoxib and were allocated to either the treatment group (n = 36) or the control group (n = 36). In addition, patients in the treatment group underwent FICB. The primary outcome was pain intensity measured using a resting and moving visual analog scales (VASs). The secondary outcomes were inflammatory factors (interleukin 6 and C-reactive protein) and occurrence rate of adverse events. RESULTS: Patients in the treatment group had better outcomes in the resting VAS (12 hours, P < .01; 24 hours, P < .01; 36 hours, P = .01; 72 hours, P = .03), moving VAS (12 hours, P < .01; 24 hours, P < .01; 36 hours, P = .02; 72 hours, P = .02), serum interleukin 6 (P < .01), and C-reactive protein (P < .01) than those in the control group at different time points. In addition, there were no significant differences in the occurrence rate of adverse events. CONCLUSION: The findings of this study demonstrated that the effects of FICB as an adjunctive management to parecoxib are superior to those of parecoxib alone for pain control after THA.

Factors influencing mosaicism: a retrospective analysis.

RESEARCH QUESTION: What factors affect the incidence of mosaic embryos resulting from assisted reproductive technology? DESIGN: A retrospective analysis of data from preimplantation genetic testing for aneuploidies in 544 couples was conducted using data from an electronic medical record database. RESULTS: Of 1910 embryos studied, 127 (6.6%) were mosaic. In multivariable logistic regression analysis, mosaicism incidence increased in embryos from IVF versus intracytoplasmic sperm injection (ICSI) (odds ratio [OR] 4.560, 95% confidence interval [CI] 2.800-7.424, P < 0.001), and in embryos from abnormal versus normal semen (OR 3.496, 95% CI 2.455-4.979, P < 0.001). Embryos tested using SurePlex 24Sure had lower mosaicism percentages than those tested using MALBAC-NGS and PicoPLEX GenetiSure (OR 2.726, 95% CI 1.532-4.852, P = 0.001; OR 2.389, 95% CI 1.537-3.711, P < 0.001, respectively). CONCLUSIONS: Semen quality, fertilization method and detection system are independent factors associated with embryonic mosaicism.

[Cloning and expression analysis of UDP-rhamnose synthase from Citrus sinensis].

Uridine diphosphate rhamnose(UDP-Rha), a glycoside donor synthesized with the catalysis of rhamnose synthase(RHM), is one of the important elements in the synthesis of rhamnosides. In this study, we cloned a RHM gene from Citrus sinensis(CsRHM) and analyzed its bioinformatic information and functions in vitro. The results showed the gene consisted of an open reading frame of 2 007 bp encoding 668 amino acid residues. The deduced protein had a presumed molecular weight of 75.27 kDa, a theoretical isoelectric point of 6.97, and the characteristic signal sequences(GxxxGxxG/A and YxxxK) of the RHM family. Multiple sequence alignments and the phylogenetic tree demonstrated that CsRHM shared homology with other RHMs. The results of enzymatic reactions in vitro showed that the recombinant protein CsRHM catalyzed the conversion of UDP-Glu to UDP-Rha, with the kinetic parameters V_(max), K_m, K_(cat), and K_(cat)/K_m of 0.373 7 µmol·L~(-1)·min~(-1), 21.29 µmol·L~(-1), 0.24 s~(-1), and 1.13×10~4 s~(-1)·L·mol~(-1), respectively. This study is the first report about CsRHM with validated catalytic function in vitro, which provides a foundation for further research on the biosynthesis of UDP-Rha.

[Effects of tHMGR from three different plant sources on mevalonate (MVA) pathway flux in Saccharomyces cerevisiae].

In this study, we used bioinformatic tools to analyze the 3-hydroxy-3-methylglutaryl-CoA reductase(HMGR) genes from Glycyrrhiza uralensis, Artemisia annua, and Arabidopsis thaliana. The results indicated that GuHMGR and AaHMGR contained two transmembrane regions while AtHMGR had three transmembrane regions. GuHMGR, AaHMGR, and AtHMGR all had the active center for catalysis. Three truncated HMGR genes(tHMGRs) of G. uralensi, A. annua, and A. thaliana were respectively ligated to pYES3 vector to construct the recombinant plasmids pYES3-tGuHMGR,pYES3-tAaHMGR,and pYES3-tAtHMGR. Afterwards, the control plasmid pYES3 and the three plasmids and were respectively introduced into Saccharomyces cerevisiae Cen.pk2-1 D, which yielded strains Y0, Y1, Y2, and Y3, respectively. The content of squalene, lanosterol, and ergosterol in these strains was measured by GC-MS. The relative expression of tGuHMGR, tAaHMGR, and tAtHMGR in strains Y1, Y2, and Y3 was determined by quantitative real-time PCR. The results showed that the strain overexpressing tAaHMGR had the highest yield of squalene and the highest total yield of squalene, ergosterol, and lanosterol. The quantitative real-time PCR showed higher relative expression of tAaHMGR than tGuHMGR, consistent with the strain fermentation result. We selected a superior tHMGR by comparing the effects of different tHMGRs on the mevalonate(MVA) pathway flux in S. cerevisiae. The findings can provide a reference for the construction of S. cerevisiae strains with high yields of squalene and terpenoid precursors.

SARS-CoV-2 ORF6 disrupts nucleocytoplasmic trafficking to advance viral replication.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) ORF6 is an antagonist of interferon (IFN)-mediated antiviral signaling, achieved through the prevention of STAT1 nuclear localization. However, the exact mechanism through which ORF6 prevents STAT1 nuclear trafficking remains unclear. Herein, we demonstrate that ORF6 directly binds to STAT1 with or without IFN stimulation, resulting in the nuclear exclusion of STAT1. ORF6 also recognizes importin α subtypes with different modes, in particular, high affinity to importin α1 but a low affinity to importin α5. Although ORF6 potentially disrupts the importin α/importin ß1-mediated nuclear transport, thereby suppressing the nuclear translocation of the other classical nuclear localization signal-containing cargo proteins, the inhibitory effect of ORF6 is modest when compared with that of STAT1. The results indicate that the drastic nuclear exclusion of STAT1 is attributed to the specific binding with ORF6, which is a distinct strategy for the importin α1-mediated pathway. Combined with the results from a newly-produced replicon system and a hamster model, we conclude that SARS-CoV-2 ORF6 acts as a virulence factor via regulation of nucleocytoplasmic trafficking to accelerate viral replication, resulting in disease progression.

Silver salt enabled H/D exchange at the ß-position of thiophene rings: synthesis of fully deuterated thiophene derivatives.

We disclose a silver catalyzed H/D exchange reaction, which can introduce the deuterium atom at the ß position of thiophene rings without the assistance of any coordinating groups. The advantages of this reaction include operation in open air, usage of D2O as the deuterium source, good tolerance to a range of functional groups and obtaining high atom% deuterium incorporation. In addition, this H/D exchange reaction is employed for direct deuteration of a thiophene based monomer, which is usually prepared by multistep synthesis from expensive deuterated starting materials.

[Construction of yeast cell factories for production of azadirachtin precursor tirucalla-7,24-dien-3ß-ol].

Azadirachtin, as a botanical insecticide, is a highly oxidized limonoid triterpenoid existing in the seeds of Azadirachta indica. However, due to the low content in the seeds, the production of azadirachtin by seed extraction has low yield. Chemical synthesis of azadirachtin is characterized by complex process and low yield. Synthetic biology provides an alternative for the supply of azadirach-tin. In this study, two oxidosqualene cyclases AiOSC1 and MaOSC1 respectively derived from A. indica and Melia azedarach were identified in yeast. A yeast strain producing tirucalla-7,24-dien-3ß-ol was constructed by integration of AiOSC1, Arabidopsis thaliana-derived squalene synthase gene(AtAQS2), and Saccharomyces cerevisiae-derived truncated 3-hydroxy-3-methyl-glutaryl coenzyme A reductase gene(PgtHMGR) into the delta site of yeast. Then, the function of MaCYP71BQ5 was successfully verified in yeast after this gene was introduced into the constructed yeast strain. This study not only laid a foundation for the biosynthesis of tirucalla-7,24-dien-3ß-ol, but also provided a chassis cell for the functional identification of cytochrome oxidases(CYP450 s) in azadirachtin biosynthesis pathway.