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In this paper, the influence of extreme service environment on the mechanical properties of C/C composites was analyzed. The mechanical tests for ordinary C/C samples and C/C samples with anti-oxidation coating were carried out under various high temperature and oxidation conditions. The properties of C/C composites with anti-oxidation coating were focused on. It was pointed out that the material properties were mainly affected by the coupling factors of high temperature, pre-stress, oxidation environment and duration. The influence laws of these factors for the high temperature strength of C/C composites with anti-oxidation coating were further discussed and summarized.

Herein, we synthesized a surface reconstructed polymeric carbon nitride through LiOH post-thermal treatment. The catalysts were applied in photocatalytic H2O2 production.

Polymer-surface interactions are crucial to many biological processes and industrial applications. Here we propose a machine learning method to connect a model polymer's sequence with its adhesion to decorated surfaces. We simulate the adhesive free energies of 20000 unique coarse-grained one-dimensional polymer sequences interacting with functionalized surfaces and build support vector regression models that demonstrate inexpensive and reliable prediction of the adhesive free energy as a function of sequence. Our work highlights the promising integration of coarse-grained simulation with data-driven machine learning methods for the design of functional polymers and represents an important step toward linking polymer compositions with polymer-surface interactions.

In metallic nanoparticles, the cluster geometric structures control the particle's electronic band structure, polarizability, and catalytic properties. Analyzing the structural properties is a complex problem; the structure of an assembled cluster changes from moment to moment due to thermal fluctuations. Conventional structural analyses based on spectroscopy or diffraction cannot determine the instantaneous structure exactly and can merely provide an averaged structure. Molecular simulations offer an opportunity to examine the assembly and evolution of metallic clusters, as the preferred assemblies and conformations can easily be visualized and explored. Here, we utilize the adaptive biasing force algorithm applied to first principles molecular dynamics to demonstrate exploration of a relatively simple system which permits comprehensive study of the small metal cluster $\ce{Au4}$ in both neutral and charged configurations. Our simulation work offers a quantitative understanding of these clusters' dynamic structure, which is significant for single-site catalytic reactions on metal clusters and provides a starting point for a detailed quantitative understanding of more complex pure metal and alloy clusters' dynamic properties., Comment: This work was supported by MICCoM, the Midwest Center for Computational Materials (www.miccom-center.org) s part of the Computational Materials Sciences Program funded by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, Materials Sciences and Engineering Division

In watermelon (Citrullus lanatus), lesion mimic is a rare, valuable trait that can be used by breeders for selection at early growth stages. In this study, we tested a seven-generation family to determine the inheritance and genetic basis of this trait. As revealed by analysis of the lesion mimic mutant clalm, this trait is controlled by a single dominant gene. Whole genome resequencing–bulked segregant analysis demonstrated that this gene is located on chromosome 4 from 3,760,000 bp to 7,440,000 bp, a region corresponding to a physical distance of 3.68 Mb encompassing approximately 72 annotated genes. There are 6 genes with non synonymous mutation SNP sites. The predicted target gene, ClCG04G001930, encodes a Phytoalexin deficient 4 (PAD4), a protein that plays an important regulatory role in leaf senescence in many plant species. According to quantitative real-time PCR analysis, the expression level of ClCG04G001930 was significantly higher in the clalm mutant than in normal watermelon. Twelve-five SNPs were identified in the ClCG04G001930 gene of F2 individuals of the clalm mutant. The leaf SA content of clalm mutant was higher than that of normal leaf. Our results suggest that ClPAD4 might be the candidate gene responsible for lesion mimic in the clalm mutant. Our findings may serve as a foundation for elucidating the mechanism underlying the molecular metabolism of programmed cell death and should be useful for marker-assisted selection breeding in watermelon.

Air pollution (AP) is a significant environmental issue that poses a potential threat to human health. Its adverse effects on human health are diverse, ranging from sensory discomfort to acute physiological reactions. As such, air quality evaluation (AQE) serves as a crucial process that involves the collection of samples from the environment and their analysis to measure AP levels. With the proliferation of Internet of Things (IoT) devices and sensors, real-time and continuous measurement of air pollutants in urban environments has become possible. However, the data obtained from multiple sources of IoT sensors can be uncertain and inaccurate, posing challenges in effectively utilizing and fusing this data. Meanwhile, differences in opinions among decision-makers regarding AQE can affect the outcome of the final decision. To tackle these challenges, this paper systematically investigates a novel multi-attribute group decision-making (MAGDM) approach based on hesitant trapezoidal fuzzy (HTrF) information and discusses its application to AQE. First, by combining HTrF sets (HTrFSs) with multi-granulation rough sets (MGRSs), a new rough set model, named HTrF MGRSs, on a two-universe model is proposed. Second, the definition and property of the presented model are studied. Third, a decision-making approach based on the background of AQE is constructed via utilizing decision-making index sets (DMISs). Lastly, the validity and feasibility of the constructed approach are demonstrated via a case study conducted in the AQE setting using experimental and comparative analyses. The outcomes of the experiment demonstrate that the presented architecture owns the ability to handle multi-source IoT sensor data (MSIoTSD), providing a sensible conclusion for AQE. In summary, the MAGDM method presented in this article is a promising scheme for solving decision-making problems, where HTrFSs possess excellent information description capabilities and can adequately describe indecision and uncertainty information. Meanwhile, MGRSs serve as an outstanding information fusion tool that can improve the quality and level of decision-making. DMISs are better able to analyze and evaluate information and reduce the impact of disagreement on decision outcomes. The proposed architecture, therefore, provides a viable solution for MSIoTSD facing uncertainty or hesitancy in the AQE environment.

Coronaviruses spike (S) glycoproteins mediate viral entry into host cells by binding to host receptors. However, how the S1 subunit undergoes conformational changes for receptor recognition has not been elucidated in Alphacoronavirus. Here, we report the cryo-EM structures of the HCoV-229E S trimer in prefusion state with two conformations. The activated conformation may pose the potential exposure of the S1-RBDs by decreasing of the interaction area between the S1-RBDs and the surrounding S1-NTDs and S1-RBDs compared to the closed conformation. Furthermore, structural comparison of our structures with the previously reported HCoV-229E S structure showed that the S trimers trended to open the S2 subunit from the closed conformation to open conformation, which could promote the transition from pre- to postfusion. Our results provide insights into the mechanisms involved in S glycoprotein-mediated Alphacoronavirus entry and have implications for vaccine and therapeutic antibody design., The spike protein of coronaviruses (S-protein) is an envelope-anchored trimeric type I transmembrane glycoprotein that mediates receptor binding and the fusion of the viral and host cell membranes. Here the authors report the conformational states of HCoV-229E S trimer and observe the conformational changes in S1 subunit from closed state to activated state for receptor binding.

E2f4 is a multifunctional transcription factor that is essential for many cellular processes. Although the role of E2f4 during cell cycle progression has been investigated in great detail, less is known about E2f4 during embryonic development. Here, we investigated the role of E2f4 during zebrafish development. Zebrafish e2f4 mutants displayed ectopic otolith formation due to abnormal ciliary beating in the otic vesicle. The beating defects of motile cilia were caused by abnormal expression of ciliary motility genes. The expression of two genes, lrrc23 and ccdc151, were significantly decreased in the absence of E2f4. In addition to that, e2f4 mutants also displayed growth retardation both in the body length and body weight and mostly died at around 6 months old. Although food intake was normal in the mutants, we found that the microvilli of the intestinal epithelia were significantly affected in the mutants. Finally, the intestinal epithelia of e2f4 mutants also displayed reduced cell proliferation, together with an increased level of cell apoptosis. Our data suggested a tissue-specific role of E2f4 during zebrafish development, which is distinct from the traditional views of this protein as a transcription repressor.

New applications of liquid crystalline materials have increased the need for precise engineering of elastic properties. Recently, Sidky et al. [H. Sidky, J. J. de Pablo, and J. K. Whitmer Phys. Rev. Lett., 2018, 120, 107801] presented methods by which the elastic coefficients of molecular models with atomistic detail can be accurately calculated, demonstrating the result for the ubiquitous mesogen 5CB. However, it is beneficial to future applications to demonstrate how the process may be refined into a precise tool for engineering functional materials. In this work, these techniques are applied to the homologous series of nCB materials and their binary mixtures, focusing on the standard bend, twist, and splay deformations, using an automated process. Our results show exceptional agreement with published experimental measurements for the nCBs and present a path forward to computational molecular engineering of liquid crystal elasticity for novel molecules and mixtures.

The receptor binding domain (RBD) of the coronavirus spike protein (S) has been verified to be the main target for potent neutralizing antibodies (nAbs) in most coronaviruses, and the N-terminal domain (NTD) of some betacoronaviruses has also been indicated to induce nAbs. For alphacoronavirus HCoV-229E, its RBD has been shown to have neutralizing epitopes, and these epitopes could change over time. However, whether neutralizing epitopes exist on the NTD and whether these epitopes change like those of the RBD are still unknown. Here, we verified that neutralizing epitopes exist on the NTD of HCoV-229E. Furthermore, we characterized an NTD targeting nAb 5H10, which could neutralize both pseudotyped and authentic HCoV-229E VR740 in vitro. Epitope mapping indicated that 5H10 targeted motif E1 (147-167 aa) and identified F159 as critical for 5H10 binding. More importantly, our results revealed that motif E1 was highly conserved among clinical isolates except for F159. Further data proved that mutations at position 159 gradually appeared over time and could completely abolish the neutralizing ability of 5H10, supporting the notion that position 159 may be under selective pressure during the human epidemic. In addition, we also found that contemporary clinical serum has a stronger binding capacity for the NTD of contemporary strains than historic strains, proving that the epitope on the NTD could change over time. In summary, these findings define a novel neutralizing epitope on the NTD of HCoV-229E S and provide a theoretical basis for the design of vaccines against HCoV-229E or related coronaviruses. IMPORTANCE Characterization of the neutralizing epitope of the spike (S) protein, the major invasion protein of coronaviruses, can help us better understand the evolutionary characteristics of these viruses and promote vaccine development. To date, the neutralizing epitope distribution of alphacoronaviruses is not well known. Here, we identified a neutralizing antibody that targeted the N-terminal domain (NTD) of the alphacoronavirus HCoV-229E S protein. Epitope mapping revealed a novel epitope that was not previously discovered in HCoV-229E. Further studies identified an important residue, F159. Mutations that gradually appeared over time at this site abolished the neutralizing ability of 5H10, indicating that selective pressure occurred at this position in the spread of HCoV-229E. Furthermore, we found that the epitopes within the NTD also changed over time. Taken together, our findings defined a novel neutralizing epitope and highlighted the role of the NTD in the future prevention and control of HCoV-229E or related coronaviruses.

Using supplementary cementitious materials (SCMs) in concrete is considered as one of the possible solutions to making green concrete. Previous research often analyzed the environmental impact of concrete without considering the influences of compressive strength and durability simultaneously. Such a practice will lead to less rational life cycle assessment (LCA) results, since the service life of concrete could be shortened when durability is poor, especially if concrete is exposed to marine dry-wet environment where chloride ion is intensive. Moreover, Fick’s second law of diffusion was always used to determine the chloride diffusion coefficient of concrete, without considering the influences of convection zone and peak value of chloride concentration. Therefore, this paper proposed an integrated functional unit combining durability (resistance to chloride ion diffusion), compressive strength and volume to evaluate the environmental impact of concrete containing SCMs. The chloride diffusion coefficient was calculated by re-scaling the ‘‘zero’’ of penetration axis to calibrate Fick’s second law of diffusion. In addition, three other functional units (volume, combining volume and compressive strength, combing volume and durability) were also proposed and compared. Results indicate that the selection of functional unit has a significant influence on the LCA results of the studied concrete. Despite the variation with different functional units, concrete containing silica fume or silica fume as well as fly ash shows a consistently superior environmental performance over the ordinary concrete.

The necrotrophic fungus Alternaria alternata contains different pathotypes that produce different mycotoxins. The pathotype Ageratina adenophora secretes the non-host-selective toxin tenuazonic acid (TeA), which can cause necrosis in many plants. Although TeA is thought to be a central virulence factor of the A. adenophora pathotype, the precise role of TeA in different stages of host infection by pathogens remains unclear. Here, an A. alternata wild-type and the toxin-deficient mutant ΔHP001 with a 75% reduction in TeA production were used. It was observed that wild-type pathogens could induce the reactive oxygen species (ROS) bursts in host leaves and killed photosynthetic cells before invading hyphae. The ROS interceptor catalase remarkably inhibited hyphal penetration and invasive hyphal growth and expansion in infected leaves and suppressed necrotic leaf lesion. This suggests that the production of ROS is critical for pathogen invasion and proliferation and disease symptom formation during infection. It was found that the mutant pathogens did not cause the formation of ROS and cell death in host leaves, showing an almost complete loss of disease susceptibility. In addition, the lack of TeA resulted in a significant reduction in the ability of the pathogen to penetrate invasive hyphal growth and spread. The addition of exogenous TeA, AAL-toxin, and bentazone to the mutant ΔHP001 pathogens during inoculation resulted in a significant restoration of pathogenicity by increasing the level of cell death, frequency of hyphal penetration, and extent of invasive hyphal spread. Our results suggest that cell death triggered by TeA is the essential requirement for successful colonization and disease development in host leaves during infection with A. adenophora pathogens.

Outbreaks of coronaviruses, especially SARS-CoV-2, pose a serious threat to global public health. Development of vaccines to prevent the coronaviruses that can infect humans has always been a top priority., Coronaviruses that infect humans belong to the Alphacoronavirus (including HCoV-229E) and Betacoronavirus (including SARS-CoV and SARS-CoV-2) genera. In particular, SARS-CoV-2 is currently a major threat to public health worldwide. The spike (S) homotrimers bind to their receptors via the receptor-binding domain (RBD), which is a major target to block viral entry. In this study, we selected Alphacoronavirus (HCoV-229E) and Betacoronavirus (SARS-CoV and SARS-CoV-2) as models. Their RBDs exist two different conformational states (“lying” or “standing”) in the prefusion S-trimer structure. Then, the differences in the immune responses to RBDs from these coronaviruses were analyzed structurally and immunologically. Our results showed that more RBD-specific antibodies (antibody titers: 1.28 × 105 and 2.75 × 105, respectively) were induced by the S-trimer with the RBD in the standing state (SARS-CoV and SARS-CoV-2) than the S-trimer with the RBD in the lying state (HCoV-229E; antibody titers

Kaposi’s sarcoma (KS), caused by Kaposi’s sarcoma-associated herpesvirus (KSHV), is a highly angioproliferative disseminated tumor of endothelial cells commonly found in AIDS patients. We have recently shown that KSHV-encoded viral interferon regulatory factor 1 (vIRF1) mediates KSHV-induced cell motility (PLoS Pathog. 2019 Jan 30;15(1):e1007578). However, the role of vIRF1 in KSHV-induced cellular transformation and angiogenesis remains unknown. Here, we show that vIRF1 promotes angiogenesis by upregulating sperm associated antigen 9 (SPAG9) using two in vivo angiogenesis models including the chick chorioallantoic membrane assay (CAM) and the matrigel plug angiogenesis assay in mice. Mechanistically, vIRF1 interacts with transcription factor Lef1 to promote SPAG9 transcription. vIRF1-induced SPAG9 promotes the interaction of mitogen-activated protein kinase kinase 4 (MKK4) with JNK1/2 to increase their phosphorylation, resulting in enhanced VEGFA expression, angiogenesis, cell proliferation and migration. Finally, genetic deletion of ORF-K9 from KSHV genome abolishes KSHV-induced cellular transformation and impairs angiogenesis. Our results reveal that vIRF1 transcriptionally activates SPAG9 expression to promote angiogenesis and tumorigenesis via activating JNK/VEGFA signaling. These novel findings define the mechanism of KSHV induction of the SPAG9/JNK/VEGFA pathway and establish the scientific basis for targeting this pathway for treating KSHV-associated cancers., Author summary Kaposi’s sarcoma-associated herpesvirus (KSHV)-encoded viral interferon regulatory factor 1 (vIRF1) is essential for KSHV-induced angiogenesis and tumorigenesis, but the underlying mechanism has not been elucidated. Sperm associated antigen 9 (SPAG9) is a well-characterized oncoprotein, highly expressed in a variety of human cancer. However, whether SPAG9 could act as a promoter of KS development has not been investigated. Here, we reveal that vIRF1 enhances SPAG9 transcription by forming a transcription factor complex with Lef1. vIRF1-induced SPAG9 upregulation promotes the interaction of mitogen-activated protein kinase kinase 4 (MKK4) with JNK together leading to enhanced JNK phosphorylation. Activation of the JNK pathway induces VEGFA expression, contributing to KSHV-induced cellular transformation and angiogenesis. In summary, this work discovers a novel mechanism of vIRF1 induction of angiogenesis and tumorigenesis, and reveals SPAG9/JNK/VEGFA pathway as a potential target for KS therapy.

Kaposi's sarcoma (KS), a highly angiogenic and invasive vascular tumor, is the most common AIDS-associated cancer caused by KS-associated herpesvirus (KSHV) infection. We have recently shown that KSHV-encoded viral interferon regulatory factor 1 (vIRF1) contributes to KSHV-induced cell motility (PLoS Pathog. 15:e1007578, 2019). However, the role of vIRF1 in KSHV-induced angiogenesis remains unknown. Here, using two in vivo angiogenesis models including the chick chorioallantoic membrane assay (CAM) and the matrigel plug angiogenesis assay in mice, we show that vIRF1 promotes angiogenesis by upregulating CUB domain (for complement C1r/C1s, Uegf, Bmp1) containing protein 1 (CDCP1). Mechanistically, vIRF1 enhances the expression of transcription factor lymphoid enhancer-binding factor 1 (Lef1) and binds to Lef1 to promote CDCP1 transcription. Meanwhile, vIRF1 degrades metastasis suppressor CD82 through an ubiquitin-proteasome pathway by recruiting E3 ubiquitin ligase AMFR to CD82, which protects CDCP1 from CD82-mediated, palmitoylation-dependent degradation. CDCP1 activates AKT signaling, which is required for vIRF1-induced cell motility but not angiogenesis. Our results illustrate that, by hijacking Lef1 and CD82, vIRF1 upregulates CDCP1 to promote angiogenesis and cell invasion. These novel findings demonstrate the vIRF1 targets multiple cellular proteins and pathways to promote the pathogenesis of KS, which could be attractive therapeutic targets for KSHV-induced malignancies.

Microcystin-LR (MC-LR) is a potent hepatotoxin that can cause liver inflammation and injury. However, the mode of action of related inflammatory factors is not fully understood. PfHMGB1 is an inflammatory factor induced at the mRNA level in the liver of juvenile yellow catfish (Pelteobagrus fulvidraco) that were intraperitoneally injected with 50 μg/kg MC-LR. The PfHMGB1 mRNA level was highest in the liver and muscle among 11 tissues examined. The full-length cDNA sequence of PfHMGB1 was cloned and overexpressed in E. coli, and the purified protein rPfHMGB1 demonstrated DNA binding affinity. Endotoxin-free rPfHMGB1 (6–150 μg/mL) also showed dose-dependent hepatotoxicity and induced inflammatory gene expression of primary hepatocytes. PfHMGB1 antibody (anti-PfHMGB1) in vitro reduced MC-LR (30 and 50 μmol/L)-induced hepatotoxicity, suggesting PfHMGB1 is important in the toxic effects of MC-LR. In vivo study showed that MC-LR upregulated PfHMGB1 protein in the liver. The anti-PfHMGB1 blocked its counterpart and reduced ALT/AST activities after MC-LR exposure. Anti-PfHMGB1 partly neutralized MC-LR-induced hepatocyte disorganization, nucleus shrinkage, mitochondria, and rough endoplasmic reticula destruction. These findings suggest that PfHMGB1 promotes MC-LR-induced liver damage in the yellow catfish. HMGB1 may help protect catfish against widespread microcystin pollution.

Qin Yang, Yingxiao Zhang, Qinglian Zeng, Chan Yang, Jiale Shi, Chunlin Zhang, Xia Ni, Zhipeng Du, Ziwei Tang, Jinbo Hu, Xuemei Li, Jiahui Cai, Qifu Li, Qingfeng Cheng Department of Endocrinology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, People’s Republic of ChinaCorrespondence: Qingfeng ChengThe First Affiliated Hospital of Chongqing Medical University, No. 1, Youyi Road, Yuanjiagang, Yuzhong District, Chongqing 400042, People’s Republic of ChinaTel +86-23-89011510Fax +86-23-890115540Email cqf19760516@163.comPurpose: The present study was designed to determine the relationships between sarcopenia and diabetic peripheral neuropathy (DPN) in patients with type 2 diabetes mellitus (T2DM) and diabetic foot disease (DFD) respectively.Patients and Methods: A total of 1104 patients with T2DM and 257 patients with DFD were included in the study, which was designed as a cross-sectional study. Body composition was assessed using dual-energy X-ray-absorptiometry (DXA). The diagnosis of sarcopenia was based on the Baumgartner criteria. DPN was assessed by Neuropathy symptom score (NSS) and Neuropathy disability score (NDS), and the severity of neuropathy was divided into non-neuropathy symptom (NS), Mild NS, Moderate NS and Severe NS according to NSS. Logistic regression analyses were carried out to determine the relations of sarcopenia and DPN in patients with T2DM and NSS in patients with DFD, respectively.Results: The prevalence of DPN was 80.0% in T2DM patients with sarcopenia and 70.3% in non-sarcopenia patients (P=0.007). Logistic regression analyses showed DPN was one of the independent risk factors for sarcopenia in T2DM patients (OR 1.564 [95% CI: 1.004, 2.435], P=0.048). The prevalence of DPN had no statistical significance in DFD patients with or without sarcopenia. However, the NSS of DFD patients with sarcopenia was higher than that of non-sarcopenia patients. In the multivariate logistic regression analysis, NSS was determined to be associated with sarcopenia in DFD patients (OR 1.387[95% CI: 1.074, 1.789], P=0.012). The appendicular lean mass (ALM) of DFD patients without NS was higher than patients with mild, moderate and severe NS (20.71± 2.73 vs 16.57± 3.62 vs 17.99± 3.54 vs 17.23± 3.29 Kg, P=0.028).Conclusion: DPN is an independent risk factor for sarcopenia in patients with T2DM and NSS is also independently correlated with sarcopenia in patients with DFD, with the latter being more obvious with the aggravation of neurological symptoms in DFD patients.Keywords: type 2 diabetes mellitus, diabetic peripheral neuropathy, diabetic foot disease, sarcopenia, correlation

Gliotoxin (GT) is a fungal secondary metabolite that has attracted great interest due to its high biological activity since it was discovered by the 1930s. It exhibits a unique structure that contains a N-C = O group as the characteristics of the classical PSII inhibitor. However, GT’s phytotoxicity, herbicidal activity and primary action targets in plants remain hidden. Here, it is found that GT can cause brown or white leaf spot of various monocotyledonous and dicotyledonous plants, being regarded as a potential herbicidal agent. The multiple sites of GT action are located in two photosystems. GT decreases the rate of oxygen evolution of PSII with an I 50 value of 60 µM. Chlorophyll fluorescence data from Chlamydomonas reinhardtii cells and spinach thylakoids implicate that GT affects both PSII electron transport at the acceptor side and the reduction rate of PSI end electron acceptors’ pool. The major direct action target of GT is the plastoquinone QB-site of the D1 protein in PSII, where GT inserts in the QB binding niche by replacing native plastoquinone (PQ) and then interrupts electron flow beyond plastoquinone QA. This leads to severe inactivation of PSII RCs and a significant decrease of PSII overall photosynthetic activity. Based on the simulated modeling of GT docking to the D1 protein of spinach, it is proposed that GT binds to the-QB-site through two hydrogen bonds between GT and D1-Ser264 and D1-His252. A hydrogen bond is formed between the aromatic hydroxyl oxygen of GT and the residue Ser264 in the D1 protein. The 4-carbonyl group of GT provides another hydrogen bond to the residue D1-His252. So, it is concluded that GT is a novel natural PSII inhibitor. In the future, GT may have the potential for development into a bioherbicide or being utilized as a lead compound to design more new derivatives.

Currently, an effective therapeutic treatment for porcine reproductive and respiratory syndrome virus (PRRSV) remains elusive. PRRSV helicase nsp10 is an important component of the replication transcription complex that plays a crucial role in viral replication, making nsp10 an important target for drug development. Here, we report the first crystal structure of full-length nsp10 from the arterivirus PRRSV, which has multiple domains: an N-terminal zinc-binding domain (ZBD), a 1B domain, and helicase core domains 1A and 2A. Importantly, our structural analyses indicate that the conformation of the 1B domain from arterivirus nsp10 undergoes a dynamic transition. The polynucleotide substrate channel formed by domains 1A and 1B adopts an open state, which may create enough space to accommodate and bind double-stranded RNA (dsRNA) during unwinding. Moreover, we report a unique C-terminal domain structure that participates in stabilizing the overall helicase structure. Our biochemical experiments also showed that deletion of the 1B domain and C-terminal domain significantly reduced the helicase activity of nsp10, indicating that the four domains must cooperate to contribute to helicase function. In addition, our results indicate that nidoviruses contain a conserved helicase core domain and key amino acid sites affecting helicase function, which share a common mechanism of helicase translocation and unwinding activity. These findings will help to further our understanding of the mechanism of helicase function and provide new targets for the development of antiviral drugs. IMPORTANCE Porcine reproductive and respiratory syndrome virus (PRRSV) is a major respiratory disease agent in pigs that causes enormous economic losses to the global swine industry. PRRSV helicase nsp10 is a multifunctional protein with translocation and unwinding activities and plays a vital role in viral RNA synthesis. Here, we report the first structure of full-length nsp10 from the arterivirus PRRSV at 3.0-Å resolution. Our results show that the 1B domain of PRRSV nsp10 adopts a novel open state and has a unique C-terminal domain structure, which plays a crucial role in nsp10 helicase activity. Furthermore, mutagenesis and structural analysis revealed conservation of the helicase catalytic domain across the order Nidovirales (families Arteriviridae and Coronaviridae). Importantly, our results will provide a structural basis for further understanding the function of helicases in the order Nidovirales.

Nidovirus endoribonucleases (NendoUs) include nonstructural protein 15 (nsp15) from coronaviruses and nsp11 from arteriviruses, both of which have been reported to participate in the viral replication process and in the evasion of the host immune system. Results from a previous study of coronaviruses SARS-CoV, HCoV-229E, and MHV nsp15 indicate that it mainly forms a functional hexamer, whereas nsp11 from the arterivirus PRRSV is a dimer. Here, we found that porcine Deltacoronavirus (PDCoV) nsp15 primarily exists as dimers and monomers in vitro. Biological experiments reveal that a PDCoV nsp15 mutant lacking the first 27 amino acids of the N-terminal domain (Asn-1–Asn-27) forms more monomers and displays decreased enzymatic activity, indicating that this region is important for its dimerization. Moreover, multiple sequence alignments and three-dimensional structural analysis indicated that the C-terminal region (His-251–Val-261) of PDCoV nsp15 is 10 amino acids shorter and forms a shorter loop than that formed by the equivalent sequence (Gln-259–Phe-279) of SARS-CoV nsp15. This result may explain why PDCoV nsp15 failed to form hexamers. We speculate that NendoUs may have originated from XendoU endoribonucleases (XendoUs) forming monomers in eukaryotic cells, that NendoU from arterivirus gained the ability to form dimers, and that the coronavirus variants then evolved the capacity to assemble into hexamers. We further propose that PDCoV nsp15 may be an intermediate in this evolutionary process. Our findings provide a theoretical basis for improving our understanding of NendoU evolution and offer useful clues for designing drugs and vaccines against nidoviruses.

Rabies is one of the most dangerous and widespread zoonosis and is characterized by severe neurological signs and a high case-mortality rate of nearly 100%. Vaccination is the most effective way to prevent rabies in humans and animals. In this study, the relationship between exhaustive exercise and the humoral immune response after immunization with inactivated rabies vaccine was investigated in a mouse model with one-time exhaustive exercise. It was found that compared with the mice with no exercise after vaccination, no significant differences were found in those with exhaustive exercise after vaccination on body-weight changes, virus-neutralizing antibody (VNA) titers, antibody subtypes and survivor ratio after lethal rabies virus (RABV) challenge. This study indicated that exhaustive exercise does not reduce the effects of the rabies inactivated vaccine.

Corrosion of reinforcing steel due to chloride attack is the main cause of deterioration of reinforced-concrete (RC) structures in a chloride environment. Chloride diffusion in concrete is time-varying and affected by many factors. It is necessary for service life prediction of RC structures to make clear how chloride diffusion coefficients change with time. In addition, the test environment has an obvious effect on the concrete's diffusivity, especially on the chloride diffusion coefficient and the age factor. Therefore, it is advisable to conduct similarity analysis of chloride ingress into concrete between an artificial simulated environment and a field marine environment. Based on the existing field exposure test, an accelerated simulated test with the same concrete mixture proportions as the exposure test under a tidal environment were designed in this paper. The free chloride concentrations in concrete with different exposure times and diffusion coefficients of concrete were obtained, and the relationship between the age factor and water/cement ratio was analysed. Finally, the similarity of the time-dependent characteristic of chloride ions in concrete between the accelerated simulation and field exposure test was investigated.