In vitro suppression of porcine epidemic diarrhea virus by Panax notoginseng saponins: assessing antiviral potential.

Porcine epidemic diarrhea virus (PEDV) causes severe diarrhea and high mortality in neonatal suckling piglets, leading to significant economic losses to the swine industry. Panax notoginseng saponins (PNS) are bioactive extracts derived from the P. notoginseng plant. In this study, we investigated the anti-PEDV effect of PNS by employing various methodologies to assess their impact on PEDV in Vero cells. Using a CCK-8 (Cell Counting Kit-8) assay, we found that PNS had no significant cytotoxicity below the concentration of 128 µg/mL in Vero cells. Using immunofluorescence assays (IFAs), an enzyme-linked immunosorbent assay (ELISA), and plaque formation assays, we observed a dose-dependent inhibition of PEDV infection by PNS within 24-48 hours postinfection. PNS exerts its anti-PEDV activity specifically at the genome replication stage, and mRNA-seq analysis demonstrated that treatment with PNS resulted in increased expression of various genes, including IFIT1 (interferon-induced protein with tetratricopeptide repeats 1), IFIT3 (interferon-induced protein with tetratricopeptide repeats 3), CFH (complement factor H), IGSF10 (immunoglobulin superfamily member 10), ID2 (inhibitor of DNA binding 2), SPP1 (secreted phosphoprotein 1), PLCB4 (phospholipase C beta 4), and FABP4 (fatty acid binding protein 4), but it resulted in decreased expression of IL1A (interleukin 1 alpha), TNFRSF19 (TNF receptor superfamily member 19), CDH8 (cadherin 8), DDIT3 (DNA damage inducible transcript 3), GADD45A (growth arrest and DNA damage inducible alpha), PTPRG (protein tyrosine phosphatase receptor type G), PCK2 (phosphoenolpyruvate carboxykinase 2), and ADGRA2 (adhesion G protein-coupled receptor A2). This study provides insights into the potential mechanisms underlying the antiviral effects of PNS. Taken together, the results suggest that the PNS might effectively regulate the defense response to the virus and have potential to be used in antiviral therapies.

The glycosylation sites in RBD of spike protein attenuate the immunogenicity of PEDV AH2012/12.

Porcine epidemic diarrhea (PED) is a highly contagious swine intestinal disease caused by PED virus (PEDV). Vaccination is a promising strategy to prevent and control PED. Previous studies have confirmed that glycosylation could regulate the immunogenicity of viral antigens. In this study, we constructed three recombinant PEDVs which removed the glycosylation sites in RBD. Viral infection assays revealed that similar replication characteristics between the recombinant viruses and parental PEDV. Although animal challenging study demonstrated that the glycosylation sites in RBD do not affect the pathogenicity of PEDV, we found that removing the glycosylation sites on the RBD regions could promote the IgG and neutralization titer in vivo, suggesting deglycosylation in RBD could enhance the immunogenicity of PEDV. These findings demonstrated that removal of the glycosylation sites in RBD is a promising method to develop PEDV vaccines.

Bone-Differentiation-Associated Circ-Spen Regulates Death of Mouse Bone Marrow Mesenchymal Stem Cells by Inhibiting Apoptosis and Promoting Autophagy.

The role of estrogen receptor ß (ERß) in bone health is closely associated with its function in vivo, and ERß-/- mice have been widely utilized to explore the related influences. In this study, ERß-/- female mice were established to investigate the differential expression of circular RNAs (circRNAs) by RNA-Sequencing (RNA-Seq). Among these circRNAs, mmu_circ_0011379 (named Circ-Spen) exhibited high expression in ERß-/- female mice. However, the precise mechanism by which Circ-Spen regulates bone health remained unclear. This study identified Circ-Spen as a positive regulator of mouse bone marrow mesenchymal stem cell (mBMSC) viability. The expression of Circ-Spen was markedly increased in ERß-/- mice femurs tested by RT-qPCR. Moreover, Circ-Spen exhibited an enhanced expression during the bone formation process of mBMSCs. Qualitative experiments also demonstrated that Circ-Spen possessed a circular structure and was localized within the nucleus of mBMSCs. Functionally, it inhibited apoptosis via caspase-3, BCL-2, and BAX, while also promoting autophagy through BECN1 and P62 in mBMSCs tested by MTT assays, transmission electron microscopy (TEM), and Western blotting. These findings reveal the potential of targeting Circ-Spen as a promising therapeutic strategy for rejuvenating senescent mBMSCs and enhancing the efficiency of mBMSC transplantation, which lays the foundation for advancements in the field of bone therapy.

The effect of weak π-π interactions on single-molecule electron transport properties of the tetraphenylethene molecule and its derivatives: a first-principles study.

Intramolecular π-π interactions are a significant research focus in fields such as chemistry, biology, and materials science. Different configurations of benzene-benzene moieties within a molecule can affect the magnitude of their π-π interactions, consequently influencing the electronic transport capabilities of the molecule. In this study, we designed three π-conjugated molecules, TPEM, TPEEM, and TEEPM, based on tetraphenylethene (TPE). These three molecules exhibit three distinct π-conjugated structures: linear cis-π-conjugation, linear trans-π-conjugation, and cross-π-conjugation. Thereinto, TPEM and TPEEM molecules share the same TPE core, with identical π-π interaction distances, while the TEEPM molecule has acetylene groups between the TPE units, thereby increasing the π-π interaction distances between the benzene moieties. Using density functional theory calculations combined with non-equilibrium Green's function (DFT+NEGF), our results reveal that the conductance order of different π-conjugated structures in TPEM and TPEEM molecules is as follows: cis > cross ≈ trans. Through analysis of transmission spectra, transmission pathways, and the innermost π orbitals, we find that in TPEM and TPEEM molecules, the cis- and cross-π-conjugated structures exhibit π-π interactions between benzene moieties and provide special through-space electron transport pathways, enhancing their electronic transport capabilities in coordination with the bonded molecular framework, whereas their trans-conjugated structures only allow electron transport along the molecular backbone. In contrast, in TEEPM molecule, due to the absence of π-π interactions, the conductance of different π-conjugated structures is primarily determined by the molecular backbone and follows the order: trans > cis > cross. These findings provide a theoretical basis for designing single-molecule electronic devices with multiple electron channels based on intramolecular π-π interactions.

Effect of S⋯π interactions on the charge transport properties of the DPP framework.

In this work, we designed and synthesized two similar π-conjugated molecules, N-alkyl (DPP-R) and N-aryl (DPP-B), to comparatively explore the S⋯π interactions using a scanning tunneling microscopy-based break junction (STM-BJ) technique. The conductance results of the STM-BJ experiments indicated that DPP-R has a 66% greater conductance (G) than DPP-B. Combined with molecular simulations, it was demonstrated that the presence of S⋯π interactions led to a certain degree of orbital overlap of the highest occupied molecular orbital (HOMO), and created a favorable channel for electron transport in the DPP-B junction.

Prevalence and related factors of cognitive frailty in diabetic patients in China: a systematic review and meta-analysis.

Objective: Cognitive frailty (CF) is characterized by physical frailty and potentially reversible cognitive impairment without Alzheimer's disease and other dementias. Clarifying the prevalence and related factors of cognitive frailty can help researchers understand its epidemiological status and formulate intervention measures. This study aims to conduct a systematic review and meta-analysis of the prevalence and related factors of CF in diabetic patients in Chinas to better understand the current status of CF in diabetic patients in China and develop effective intervention measures for related factors. Methods: PubMed, Web of Science, Embase, Cochrane Library, CNKI, Weipu(VIP), WANFANG, China Biology Medicine (CBM) and DUXIU were searched to collect epidemiological data on Chinese diabetic patients. Articles published through May 29, 2023, were searched. The number of diabetes with CF and the total number of diabetes in the included studies were extracted to estimate the prevalence of diabetes with CF. For factors related to diabetes with CF, odds ratios (OR) and 95% confidence intervals (CI) were used for estimation. Results: A total of 248 records were screened, of which 18 met the inclusion criteria. The results of meta-analysis showed that the prevalence of Chinese diabetic patients with CF was 25.8% (95% CI = 19.7 to 31.9%). Subgroup analysis showed that hospital prevalence was higher than in the community and in women than in men. Combined estimates showed that depression, malnutrition, advanced age (≥70, ≥80), combined chronic diseases ≥4 and glycated hemoglobin ≥8.5 were risk factors for CF in diabetics patients in China, with regular exercise and high education level (≥ college) as protective factors. Conclusion: Cognitive frailty was common in diabetic patients in China. Such populations should be screened early and intervened with relevant factors.Systematic review registration: A systematic review of this study evaluated the registered websites as https://www.crd.york.ac.uk/PROSPERO/, CRD42023431396.

Genetic signatures associated with the virulence of porcine epidemic diarrhea virus AH2012/12.

IMPORTANCE: Porcine epidemic diarrhea (PED) caused by PED virus (PEDV) remains a big threat to the swine industry worldwide. Vaccination with live attenuated vaccine is a promising method to prevent and control PED, because it can elicit a more protective immunity than the killed vaccine, subunit vaccine, and so on. In this study, we found two obvious deletions in the genome of a high passage of AH2012/12. We further confirmed the second deletion which contains seven amino acids at the carboxy-terminus of the S2 gene and the start codon of ORF3 can reduce its pathogenicity in vivo. Animal experiments indicated that the recombinant PEDV with deleted carboxy-terminus of S gene showed higher IgG, IgA, neutralization antibodies, and protection effects against virus challenge than the killed vaccine. These data reveal that the engineering of the carboxy-terminus of the S2 gene may be a promising method to develop live attenuated vaccine candidates of PEDV.

Analysis of Sinus Inflammation Associated With Maxillary Sinus Fungal Ball Based on CT Imaging.

Background: Paranasal sinus fungal balls usually occur unilaterally, and the maxillary sinus is most commonly involved. However, other sinuses could be concomitantly inflammed, and this phenomenon is rarely discussed. Aims/Objectives: To evaluate the severity of maxillary sinus fungal ball (MSFB) and the occurrence of sinus inflammation in paranasal sinuses according to the image findings and analyze the potential correlations. Material and Methods: A total of 1226 cases of MSFB were divided into 2 groups according to ostiomeatal complex obstruction on computed tomography. The potential correlations between sinus inflammation and MSFB in these groups were analyzed. Results: The patients were divided into 2 groups: those with obstructed ostiomeatal complex (OOMC) and those with clear ostiomeatal complex (COMC). The incidences of sinus inflammation in the ipsilateral sinuses of MSFB were higher in the OOMC group than in the COMC group, and there were no differences in the contralateral sinuses of MSFB. In the OOMC group, sinus inflammation was more common in all ipsilateral sinuses of MSFB than in the contralateral sinuses. In the COMC group, the incidences of sinus inflammation in the ipsilateral ethmoid and frontal sinuses of MSFB were higher than that in the contralateral sinuses. However, no significant difference was observed in the sinus inflammation incidence of bilateral sphenoid sinuses in the COMC group. The incidence of nasal polyps was higher in the ipsilateral nasal cavity in the OOMC group. Conclusions and Significance: MSFB stimulated sinus inflammation and nasal polyps in the adjacent sinuses through local factors.

H3K27me3 of Rnf19a promotes neuroinflammatory response during Japanese encephalitis virus infection.

Histone methylation is an important epigenetic modification that affects various biological processes, including the inflammatory response. In this study, we found that infection with Japanese encephalitis virus (JEV) leads to an increase in H3K27me3 in BV2 microglial cell line, primary mouse microglia and mouse brain. Inhibition of H3K27me3 modification through EZH2 knockdown and treatment with EZH2 inhibitor significantly reduces the production of pro-inflammatory cytokines during JEV infection, which suggests that H3K27me3 modification plays a crucial role in the neuroinflammatory response caused by JEV infection. The chromatin immunoprecipitation-sequencing (ChIP-sequencing) assay revealed an increase in H3K27me3 modification of E3 ubiquitin ligases Rnf19a following JEV infection, which leads to downregulation of Rnf19a expression. Furthermore, the results showed that Rnf19a negatively regulates the neuroinflammatory response induced by JEV. This is achieved through the degradation of RIG-I by mediating its ubiquitination. In conclusion, our findings reveal a novel mechanism by which JEV triggers extensive neuroinflammation from an epigenetic perspective.

The Nasal Bacteria Microbiome Comparison Among Fungal Ball Sinusitis, Chronic Sinusitis with Polyps.

To evaluate the composition of the microbial community of the middle nasal in paranasal sinus fungus ball (FB), chronic sinusitis with nasal polyps (CRSwNP) and healthy controls, providing new insights into the pathogenesis of FB and CRSwNP. Through 16 s rRNA gene high-throughput sequencing to determine the microbial characterization from patients with FB (n = 29) and CRSwNP (n = 10), and healthy controls (n = 4). The FB group had significantly lower αdiversity and significantly different ß diversity compared to the other groups. All three groups mainly consisted of four bacterial phyla (Firmicutes, Proteobacteria, Bacteroidetes, Actinobacteria). In the FB group, the highest relative abundance was found in Proteobacteria (47.04%). However, pairwise comparisons resulted in statistically significant differences only for Firmicutes (CRSwNP, p = 0.003, Control, p = 0.008). The CRSwNP group was statistically different from the control group in TM7(p = 0.010), Chloroflexi(p = 0.018) and Bacteroidete(p = 0.027). At the genus level, the FB group had the highest relative abundance of Haemophilus (11.53%), followed by Neisseria (7.39%), and Neisseria abundance (p < 0.001) was significantly different from the remaining two groups. Ruminococcacea abundance (p < 0.001) and Comamonadaceae abundance (p < 0.001) were increased in the CRSwNP group. The relative abundance of Lactobacillus (p < 0.001), Bacteroides S24_7 (p < 0.001), and Desulfovibrio (p < 0.001) was significantly decreased in the FB and CRSwNP groups compared to the control group. The imbalance of the microbial community is related to the pathogenesis of sinusitis.

Correlation between the IgG/IgA Antibody Response against PEDV Structural Protein and Virus Neutralization.

Porcine epidemic diarrhea (PED) is a highly contagious intestinal infectious disease caused by porcine epidemic diarrhea virus (PEDV). Large-scale outbreaks of PEDV have caused huge economic losses to the pig industry since 2010. Neutralizing antibodies play a pivotal role in protecting piglets from enteric infections. However, there has been no systematic report on the correlations between neutralizing antibody titers (NTs) and absorbance values of IgG or IgA to all PEDV individual structural proteins in clinical serum, fecal, and colostrum samples. In this study, the spike protein S1 domain (S1), membrane protein (M), envelope protein (E), and nucleocapsid protein (N) of the variant PEDV strain AH2012/12 were expressed and purified by using the human embryonic kidney (HEK) 293F expression system. A total of 92 clinical serum samples, 46 fecal samples, and 33 colostrum samples were collected, and the correlations between IgG or IgA absorbance values and NTs were analyzed. R2 values revealed that anti-S1 IgA absorbance values show the highest agreement with NTs in all serum, fecal, and colostrum samples, followed by the N protein. The correlations between anti-E or M IgA and NTs were very low. However, in the colostrum samples, both IgG and IgA to S1 showed high correlations with NTs. In addition, compared with E and M, the highest correlations of IgA absorbance values were with N and S1 in serum and fecal samples. Overall, this study revealed the highest correlation between NTs and IgA to PEDV S1 protein. Therefore, the diagnostic method with anti-S1 IgA can be used as a powerful tool for assessing the immune status of pigs. IMPORTANCE The humoral immune response plays an important role in virus neutralization. Against PEDV, both IgG and the mucosal immune component IgA play roles in virus neutralization. However, which plays a more prominent role and whether there are differences in different tissue samples are not clearly reported. Additionally, the relationship between IgG and IgA against individual structural proteins and viral neutralization remains unclear. In this study, we systematically determined the relationship between IgG and IgA against all PEDV structural proteins and viral neutralization in different clinical samples and found the highest correlation between neutralization activity and IgA to PEDV S1 protein. Our data have important guiding implications in the evaluation of immune protection.

Transcriptomic and antiviral analyses of PoIFN-Delta5 against porcine enteric viruses in porcine intestinal epithelial cells.

The interferon-delta family was first reported in domestic pigs and belongs to the type I interferon (IFN-I) family. The enteric viruses could cause diarrhea in newborn piglets with high morbidity and mortality. We researched the function of the porcine IFN-delta (PoIFN-δ) family in the porcine intestinal epithelial cells (IPEC-J2) cells infected with porcine epidemic diarrhea virus (PEDV). Our study found that all PoIFN-δs shared a typical IFN-I signature and could be divided into five branches in the phylogenic tree. Different strains of PEDV could induce typical IFN transitorily, and the virulent strain AH2012/12 had the strongest induction of porcine IFN-δ and IFN-alpha (PoIFN-α) in the early stage of infection. In addition, it was found that PoIFN-δ5/6/9/11 and PoIFN-δ1/2 were highly expressed in the intestine. PoIFN-δ5 had a better antiviral effect on PEDV compared to PoIFN-δ1 due to its higher induction of ISGs. PoIFN-δ1 and PoIFN-δ5 also activated JAK-STAT and IRS signaling. For other enteric viruses, transmissible gastroenteritis virus (TGEV), porcine deltacoronavirus (PDCoV), and porcine rotavirus (PoRV), PoIFN-δ1 and PoIFN-δ5 both showed an excellent antiviral effect. Transcriptome analyses uncovered the differences in host responses to PoIFN-α and PoIFN-δ5 and revealed thousands of differentially expressed genes were mainly enriched in the inflammatory response, antigen processing and presentation, and other immune-related pathways. PoIFN-δ5 would be a potential antiviral drug, especially against porcine enteric viruses. These studies were the first to report the antiviral function against porcine enteric viruses and broaden the new acquaintances of this type of interferon though not novelly discovered.

Value of Opening the Middle Meatus in Patients With Nasal Airway Obstruction.

OBJECTIVES: While surgeries to correct the anatomical malformations that cause nasal airway obstruction (NAO) are generally successful, the outcomes of such procedures are often unsatisfactory. The aim of the present study was to assess the value of opening the middle meatus in patients with NAO. METHODS: Thirty-four patients with nasal obstruction due to nasal septal deviation were included in this study. After randomization, the middle meatus was either opened or not opened during septoplasty. The patients were evaluated through pre- and postoperative rhinomanometry and acoustic rhinometry. The Visual Analog Scale (VAS) scores of subjective symptoms along with responses to the 20-item Sinonasal Outcome Test (SNOT-20) were obtained before surgery and three months after surgery. RESULTS: The VAS scores and SNOT-20 responses improved significantly in both groups after surgery. The effective treatment rate based on the nasal congestion score (NCS) was 64.7% in the single group (septoplasty alone) and 100% in the combined group (septoplasty in conjunction with opening the middle meatus), and the difference was statistically significant (P = .018). In both groups, surgery significantly improved nasal flow, resistance, minimal cross-sectional area, cross-sectional area 6 cm (CA6) from the anterior nostril and nasal volume. Nasal volume and CA6 after surgery were statistically different between the 2 groups (P = .004 and .019, respectively). CONCLUSIONS: Opening the middle meatus may further improve the subjective perception of patency on the basis of septoplasty.

Identification of Cell Types and Transcriptome Landscapes of Porcine Epidemic Diarrhea Virus-Infected Porcine Small Intestine Using Single-Cell RNA Sequencing.

Swine coronavirus-porcine epidemic diarrhea virus (PEDV) with specific susceptibility to pigs has existed for decades, and recurrent epidemics caused by mutant strains have swept the world again since 2010. In this study, single-cell RNA sequencing was used to perform for the first time, to our knowledge, a systematic analysis of pig jejunum infected with PEDV. Pig intestinal cell types were identified by representative markers and identified a new tuft cell marker, DNAH11. Excepting enterocyte cells, the goblet and tuft cells confirmed susceptibility to PEDV. Enrichment analyses showed that PEDV infection resulted in upregulation of cell apoptosis, junctions, and the MAPK signaling pathway and downregulation of oxidative phosphorylation in intestinal epithelial cell types. The T cell differentiation and IgA production were decreased in T and B cells, respectively. Cytokine gene analyses revealed that PEDV infection downregulated CXCL8, CXCL16, and IL34 in tuft cells and upregulated IL22 in Th17 cells. Further studies found that infection of goblet cells with PEDV decreased the expression of MUC2, as well as other mucin components. Moreover, the antimicrobial peptide REG3G was obviously upregulated through the IL33-STAT3 signaling pathway in enterocyte cells in the PEDV-infected group, and REG3G inhibited the PEDV replication. Finally, enterocyte cells expressed almost all coronavirus entry factors, and PEDV infection caused significant upregulation of the coronavirus receptor ACE2 in enterocyte cells. In summary, this study systematically investigated the responses of different cell types in the jejunum of piglets after PEDV infection, which deepened the understanding of viral pathogenesis.

Nonstructural Protein 1 of Variant PEDV Plays a Key Role in Escaping Replication Restriction by Complement C3.

Zoonotic coronaviruses represent an ongoing threat to public health. The classical porcine epidemic diarrhea virus (PEDV) first appeared in the early 1970s. Since 2010, outbreaks of highly virulent PEDV variants have caused great economic losses to the swine industry worldwide. However, the strategies by which PEDV variants escape host immune responses are not fully understood. Complement component 3 (C3) is considered a central component of the three complement activation pathways and plays a crucial role in preventing viral infection. In this study, we found that C3 significantly inhibited PEDV replication in vitro, and both variant and classical PEDV strains induced high levels of interleukin-1ß (IL-1ß) in Huh7 cells. However, the PEDV variant strain reduces C3 transcript and protein levels induced by IL-1ß compared with the PEDV classical strain. Examination of key molecules of the C3 transcriptional signaling pathway revealed that variant PEDV reduced C3 by inhibiting CCAAT/enhancer-binding protein ß (C/EBP-ß) phosphorylation. Mechanistically, PEDV nonstructural protein 1 (NSP1) inhibited C/EBP-ß phosphorylation via amino acid residue 50. Finally, we constructed recombinant PEDVs to verify the critical role of amino acid 50 of NSP1 in the regulation of C3 expression. In summary, we identified a novel antiviral role of C3 in inhibiting PEDV replication and the viral immune evasion strategies of PEDV variants. Our study reveals new information on PEDV-host interactions and furthers our understanding of the pathogenic mechanism of this virus. IMPORTANCE The complement system acts as a vital link between the innate and the adaptive immunity and has the ability to recognize and neutralize various pathogens. Activation of the complement system acts as a double-edged sword, as appropriate levels of activation protect against pathogenic infections, but excessive responses can provoke a dramatic inflammatory response and cause tissue damage, leading to pathological processes, which often appear in COVID-19 patients. However, how PEDV, as the most severe coronavirus causing diarrhea in piglets, regulates the complement system has not been previously reported. In this study, for the first time, we identified a novel mechanism of a PEDV variant in the suppression of C3 expression, showing that different coronaviruses and even different subtype strains differ in regulation of C3 expression. In addition, this study provides a deeper understanding of the mechanism of the PEDV variant in immune escape and enhanced virulence.

Differential expression profile of plasma exosomal microRNAs in chronic rhinosinusitis with nasal polyps.

Exosomes mediate inflammation and immune responses. The aim of the study was to examine the expression profiles of plasma exosomal microRNAs (miRNAs) and analyze their target gene functions in participants with chronic rhinosinusitis with nasal polyps (CRSwNP). We measured plasma exosomal miRNAs in five patients with CRSwNP and five controls. Transcripts per million (TPM) was used to assess miRNAs expression and the Benjamini-Hochberg procedure was employed for multiple comparisons correction. Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene ontology (GO) analyses revealed biological annotation and functional prediction of target genes. Compared with controls, we found that 159 exosomal miRNAs were differentially expressed by miRNA sequencing in CRSwNP. The top three upregulated miRNAs were novel_miR_677, novel_miR_1037, and novel_miR_79, while the top three downregulated miRNAs were novel_miR_192, novel_miR_1022, and novel_miR_4. The target functions in the GO and KEGG analyses included axon guidance, extracellular matrix (ECM)-receptor interaction, protein digestion and absorption, the calcium, the Hippo, the Notch, the ErbB, the cAMP signaling pathway, and focal adhesion. This study describes the dissection of plasma exosomal miRNA profiling in CRSwNP. Our findings may provide a certain basis for further mechanism research and exploration of diagnostic values.

Dynamic Interconversions of Single Molecules Probed by Recognition Tunneling at Cucurbit[7]uril-Functionalized Supramolecular Junctions.

We introduce a versatile recognition tunneling technique using doubly cucurbit[7]uril-functionalized electrodes to form supramolecular junctions that capture analytes dynamically by host-guest complexation. This results in characteristic changes in their single-molecule conductance. For structurally related drug molecules (camptothecin, sanguinarine, chelerythrine, and berberine) and mixtures thereof, we observed distinct current switching signals related to their intrinsic conductance properties as well as pH-dependent effects which can be traced back to their different states (protonated versus neutral). The conductance variation of a single molecule with pH shows a sigmoidal distribution, allowing us to extract a pKa value for reversible protonation, which is consistent with the reported macroscopic results. The new electronic method allows the characterization of unmodified drug molecules and showcases the transfer of dynamic supramolecular chemistry principles to single molecules.

The effect of non-covalent conformational locks on intra-molecular charge transport of OPV units.

Although organic photovoltaic (OPV) molecules containing non-covalent conformational locks (NCLs) are demonstrated with superior device scale charge transport, the NCLs' working mechanism at the molecular level has not been directly addressed or revealed. Herein, three widely used OPV building blocks DT-BT, DT-FBT, and DT-OBT were prepared and comparatively researched for their intra-molecule charge transport (ICT) based on single molecular conductance measurements and theoretical calculation. The measured conductance (G) of the three molecules displays an order of GDT-BT < GDT-FBT < GDT-OBT, contradicting the conductivity order predicted by tunnelling theory. Further research demonstrated that this change was mainly caused by NCLs embedded in DT-FBT and DT-OBT, resulting in more efficient charge transporting pathways, evidenced by their HOMOs showing hyper-conjugation characteristics.

Evaluation of the transcriptional regulatory efficacy of transcription regulatory sequences of porcine epidemic diarrhea virus.

Porcine epidemic diarrhea virus (PEDV) is a highly contagious enteropathogenic coronavirus causing severe watery diarrhea and high mortality in piglets. In order to investigate the role of the transcription regulatory sequences (TRSs) in regulation of gene expression and replication of PEDV, the enhanced green fluorescent protein (EGFP) gene, under control of different TRSs of PEDV, were inserted between the N gene and 3' UTR of the PEDV genome using a reverse genetic system. The EGFP expression from different chimeric PEDVs was analyzed for each TRS. TRSs of all the structural and accessory protein genes of PEDV positively regulate EGFP expression at different levels, and the TRS of M protein gene produced the highest level of EGFP. Moreover, this is the first study to show that exogenous gene could be inserted between N gene and 3' UTR of PEDV, and the EGFP insertion had no effect on PEDV replication. Taken together, our study enriched the information of PEDV TRSs on gene expression and replication of PEDV.

Mechanistic Investigation and Conductance Modulation of a Metal-Molecule-Metal Junction via Extra Acid Addition.

One important prerequisite for the fabrication of molecular functional device strongly relies on the understanding the conducting behaviors of the metal-molecule-metal junction that can respond to an external stimulus. The model Lewis basic molecule 4,4'-(pyridine-3,5-diyl)dibenzonitrile (DBP), which can react with Lewis acid and protic acid, was synthesized. Then, the molecular conducting behavior of DBP, DBP-B(C6 F5 )3 , and DBP-TfOH (DBP-B(C6 F5 )3 , and DBP-TfOH were produced by Lewis acid and protonic acid treatment of DBP) was researched and compared. Given that their identical physical paths for DBP, DBP-B(C6 F5 )3 , and DBP-TfOH to sustain charge transport, our results indicate that modifying the molecular electronic structure, even not directly changing the conductive physical backbone, can tune the charge transporting ability by nearly one order of magnitude. Furthermore, the addition of another Lewis base triethylamine (of stronger alkaline than DBP), to Lewis acid-base pair reverts the electrical properties back to that of a single DBP junction, that is constructive to propose a useful but simple strategy for the design and construction of reversible and controllable molecular device based on pyridine derived molecule.