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African swine fever (ASF) is an acute hemorrhagic disease of domestic pigs. The causative agent of ASF, ASF virus (ASFV), is a double-stranded DNA virus, the sole member in the family Asfarviridae. The non-structural protein pB602L of ASFV is a molecular chaperone of the major capsid protein p72 and plays a key role in icosahedral capsid assembly. This protein is antigenic and is a target for developing diagnostic tools for ASF. To generate monoclonal antibodies (mAbs) against pB602L, a prokaryotically expressed recombinant pB602L protein was produced, purified, and used as an antigen to immunize mice. A total of eight mouse mAbs were obtained, and their binding epitopes were screened by Western blot using an overlapping set of polypeptides from pB602L. Three linear epitopes were identified and designated epitope 1 (366ANRERYNY373), epitope 2 (415GPDAPGLSI423), and epitope 3 (498EMLNVPDD505). Based on the epitope recognized, the eight mAbs were placed into three groups: group 1 (B2A1, B2F1, and B2D10), group 2 (B2H10, B2B2, B2D8, and B2A3), and group 3 (B2E12). The mAbs B2A1, B2H10, and B2E12, each representing one of the groups, were used to detect pB602L in ASFV-infected porcine alveolar macrophages (PAMs) and pig tissues, using an indirect fluorescence assay (IFA) and immunohistochemical staining, respectively. The results showed that pB602L was detectable with all three mAbs in immunohistochemical staining, but only B2H10 was suitable for detecting the proteins in ASFV-infected PAMs by IFA. In summary, we developed eight anti-pB602L mouse mAbs recognizing three linear epitopes in the protein, which can be used as reagents for basic and applied research on ASFV.

Zika virus (ZIKV) is transmitted mostly via mosquito bites and no vaccine is available, so it may reemerge. We and others previously demonstrated that neonatal infection of ZIKV results in heart failure and can be fatal. Animal models implicated ZIKV involvement in viral heart diseases. It is unknown whether and how ZIKV causes heart failure in adults. Herein, we studied the effects of ZIKV infection on the heart function of adult A129 mice. First, we found that ZIKV productively infects the rat-, mouse-, or human-originated heart cell lines and caused ubiquitination-mediated degradation of and distortive effects on connexin 43 (Cx43) protein that is important for communications between cardiomyocytes. Second, ZIKV infection caused 100% death of the A129 mice with decreasing body weight, worsening health score, shrugging fur, and paralysis. The viral replication was detected in multiple organs. In searching for the viral effects on heart of the A129 mice, we found that ZIKV infection resulted in the increase of cardiac muscle enzymes, implicating a viral acute myocardial injury. ZIKV-caused heart injury was also demonstrated by electrocardiogram (ECG) showing widened and fragmented QRS waves, prolonged PR interval, and slower heart rate. The intercalated disc (ICD) between two cardiomyocytes was destroyed, as shown by the electronic microscopy, and the Cx43 distribution in the ICDs was less organized in the ZIKV-infected mice compared to that in the phosphate-buffered saline (PBS)-treated mice. Consistently, ZIKV productively infected the heart of A129 mice and decreased Cx43 protein. Therefore, we demonstrated that ZIKV infection caused heart failure, which might lead to fatal sequelae in ZIKV-infected A129 mice.

Background Staphylococcus aureus causes community- and hospital-acquired pneumonia linked to a high mortality rate. The emergence and rapid transmission of multidrug-resistant S. aureus strains has become a serious health concern, highlighting the challenges associated with the development of a vaccine to combat S. aureus pneumonia. Methods This study evaluated the effects of intrapulmonary immunization on the immune response and protection against S. aureus lung infection in a respiratory mouse model using a subunit vaccine. Results Compared with the intranasal immunized mice, the intrapulmonarily immunized mice had lower levels of pulmonary bacterial colonization and lethality, accompanied by alleviated lung inflammation with reduced proinflammatory cytokines and increased levels of interleukin-10 and antimicrobial peptide following intrapulmonary challenge. Optimal protection was associated with increased pulmonary antibodies and resident memory T cells. Moreover, intrapulmonary immunization provided long-lasting pulmonary protection for at least 6 months, with persistent cellular and humoral immunity in the lungs. Conclusions Vaccine reaching the deep lung by intrapulmonary immunization plays a significant role in the induction of efficacious and long-lasting immunity against S. aureus in the lung parenchyma. Hence, intrapulmonary immunization can be a strategy for the development of a vaccine against S. aureus pneumonia. Immunization through the intrapulmonary route with a subunit of S. aureus vaccine elicited tissue resident memory T cells and antigen-specific antibodies in the lungs, and provided optimal and long-term protection against S. aureus pneumonia.

Dilated cardiomyopathy (DCM) is a cardiac disease marked by the stretching and thinning of the heart muscle and impaired left ventricular contractile function. While most patients do not develop significant cardiac diseases from myocarditis, disparate immune responses can affect pathological outcomes, including DCM progression. These altered immune responses, which may be caused by genetic variance, can prolong cytotoxicity, induce direct cleavage of host protein, or encourage atypical wound healing responses that result in tissue scarring and impaired mechanical and electrical heart function. However, it is unclear which alterations within host immune profiles are crucial to dictating the outcomes of myocarditis. Coxsackievirus B3 (CVB3) is a well-studied virus that has been identified as a causal agent of myocarditis in various models, along with other viruses such as adenovirus, parvovirus B19, and SARS-CoV-2. This paper takes CVB3 as a pathogenic example to review the recent advances in understanding virus-induced immune responses and differential gene expression that regulates iron, lipid, and glucose metabolic remodeling, the severity of cardiac tissue damage, and the development of DCM and heart failure.

Coxsackievirus B3 (CVB3) is a positive single-strand RNA virus causing myocarditis, pancreatitis and meningitis. During CVB3 infection, various host cellular components, including proteins and non-coding RNAs, interact with the virus and affect viral infection. Poly(rC) binding protein 1 (PCBP1) is a multifunctional RNA binding protein regulating transcription, translation and mRNA stability of a variety of genes. In this study, we observed a significant reduction of PCBP1 protein during CVB3 infection. By bioinformatic prediction and luciferase-assay verification, we confirmed that the expression of PCBP1 was directly inhibited by miR-21, a microRNA upregulated during CVB3 infection. Furthermore, we found that overexpression of PCBP1 promoted CVB3 infection and knocking down of PCBP1 inhibited it. In the subsequent mechanism study, our results revealed that PCBP1 blocked the translation of p62/SQSTM1 (sequestosome 1), an autophagy-receptor protein suppressing CVB3 replication, by interacting with the cis-element in the 5' untranslational region (5' UTR) of p62/SQSTM1. In summary, our studies have identified PCBP1 as a beneficial factor for CVB3 infection. These findings may deepen the understanding of host-virus interactions and provide a potential target for intervention of CVB3 infection.

The low fidelity of foot-and-mouth disease virus (FMDV) RNA-dependent RNA polymerase allows FMDV to exhibit high genetic diversity. Previously, we showed that the genetic diversity of FMDV plays an important role in virulence in suckling mice. Here, we mutated the amino acid residue Phe257, located in the finger domain of FMDV polymerase and conserved across FMDV serotypes, to a cysteine (F257C) to study the relationship between viral genetic diversity, virulence, and transmissibility in natural hosts. The single amino acid substitution in FMDV polymerase resulted in a high-fidelity virus variant, rF257C, with growth kinetics indistinguishable from those of wild-type (WT) virus in cell culture, but it displayed smaller plaques and impaired fitness in direct competition assays. Furthermore, we found that rF257C was attenuated in vivo in both suckling mice and pigs (one of its natural hosts). Importantly, contact exposure experiments showed that the rF257C virus exhibited reduced transmissibility compared to that of wild-type FMDV in the porcine model. This study provides evidence that FMDV genetic diversity is important for viral virulence and transmissibility in susceptible animals. Given that type O FMDV exhibits the highest genetic diversity among all seven serotypes of FMDV, we propose that the lower polymerase fidelity of the type O FMDV could contribute to its dominance worldwide. IMPORTANCE Among the seven serotypes of FMDV, serotype O FMDV have the broadest distribution worldwide, which could be due to their high virulence and transmissibility induced by high genetic diversity. In this paper, we generated a single amino acid substitution FMDV variant with a high-fidelity polymerase associated with viral fitness, virulence, and transmissibility in a natural host. The results highlight that maintenance of viral population diversity is essential for interhost viral spread. This study provides evidence that higher genetic diversity of type O FMDV could increase both virulence and transmissibility, thus leading to their dominance in the global epidemic.

Foot-and-mouth disease (FMD), which is caused by FMD virus (FMDV), remains a major plague among cloven-hoofed animals worldwide, and its outbreak often has disastrous socioeconomic consequences. A live-attenuated FMDV vaccine will greatly facilitate the global control and eradication of FMD, but a safe and effective attenuated FMDV vaccine has not yet been successfully developed. Here, we found that the internal ribosome entry site (IRES) element in the viral genome is a critical virulence determinant of FMDV, and a nucleotide substitution of cytosine (C) for guanine (G) at position 351 of the IRES endows FMDV with temperature-sensitive and attenuation (ts&att) phenotypes. Furthermore, we demonstrated that the C351G mutation of IRES causes a temperature-dependent translation defect by impairing its binding to cellular pyrimidine tract-binding protein (PTB), resulting in the ts&att phenotypes of FMDV. Natural hosts inoculated with viruses carrying the IRES C351G mutation showed no clinical signs, viremia, virus excretion, or viral transmission but still produced a potent neutralizing antibody response that provided complete protection. Importantly, the IRES C351G mutation is a universal determinant of the ts&att phenotypes of different FMDV strains, and the C351G mutant was incapable of reversion to virulence during in vitro and in vivo passages. Collectively, our findings suggested that manipulation of the IRES, especially its C351G mutation, may serve as a feasible strategy to develop live-attenuated FMDV vaccines. IMPORTANCE The World Organization for Animal Health has called for global control and eradication of foot-and-mouth disease (FMD), the most economically and socially devastating disease affecting animal husbandry worldwide. Live-attenuated vaccines are considered the most effective strategy for prevention, control, and eradication of infectious diseases due to their capacity to induce potent and long-lasting protective immunity. However, efforts to develop FMD virus (FMDV) live-attenuated vaccines have achieved only limited success. Here, by structure-function study of the FMDV internal ribosome entry site (IRES), we find that the C351 mutation of the IRES confers FMDV with an ideal temperature-sensitive attenuation phenotype by decreasing its interaction with cellular pyrimidine tract-binding protein (PTB) to cause IRES-mediated temperature-dependent translation defects. The temperature-sensitive attenuated strains generated by manipulation of the IRES address the challenges of FMDV attenuation differences among various livestock species and immunogenicity maintenance encountered previously, and this strategy can be applied to other viruses with an IRES to rationally design and develop live-attenuated vaccines.

Upon infection, the highly structured 5′ untranslated region (5′ UTR) of picornavirus is involved in viral protein translation and RNA synthesis. As a critical element in the 5′ UTR, the internal ribosome entry site (IRES) binds to various cellular proteins to function in the processes of picornavirus replication. Foot-and-mouth disease virus (FMDV) is an important member in the family Picornaviridae, and its 5′ UTR contains a functional IRES element. In this study, the cellular heterogeneous nuclear ribonucleoprotein L (hnRNP L) was identified as an IRES-binding protein for FMDV by biotinylated RNA pulldown assays, mass spectrometry (MS) analysis, and determination of hnRNP L-IRES interaction regions. Further, we found that hnRNP L inhibited the growth of FMDV through binding to the viral IRES and that the inhibitory effect of hnRNP L on FMDV growth was not due to FMDV IRES-mediated translation, but to influence on viral RNA synthesis. Finally, hnRNP L was demonstrated to coimmunoprecipitate with RNA-dependent RNA polymerase (3D(pol)) in an FMDV RNA-dependent manner in the infected cells. Thus, our results suggest that hnRNP L, as a critical IRES-binding protein, negatively regulates FMDV replication by inhibiting viral RNA synthesis, possibly by remaining in the replication complex. IMPORTANCE Picornaviruses, as a large family of human and animal pathogens, cause a bewildering array of disease syndromes. Many host factors are implicated in the pathogenesis of these viruses, and some proteins interact with the viral IRES elements to affect function. Here, we report for the first time that cellular hnRNP L specifically interacts with the IRES of the picornavirus FMDV and negatively regulates FMDV replication through inhibiting viral RNA synthesis. Further, our results showed that hnRNP L coimmunoprecipitates with FMDV 3D(pol) in a viral RNA-dependent manner, suggesting that it may remain in the replication complex to function. The data presented here would facilitate further understanding of virus-host interactions and the pathogenesis of picornavirus infections.

Cap-independent translation initiation on picornavirus mRNAs is mediated by an internal ribosomal entry site (IRES) in the 5′ untranslated region. The regulation of internal initiation requires the interaction of IRES-transacting factors (ITAFs) with the IRES. In this study, we identified a novel ITAF, heterogeneous nuclear ribonucleoprotein K (hnRNP K), which negatively regulates foot-and-mouth disease virus (FMDV) translation and viral replication. Further investigation revealed that the KH2 and KH3 domains of hnRNP K directly bind to domains II, III, and IV of the FMDV IRES, resulting in the inhibition of IRES-mediated translation by interfering with the recognition of another positive ITAF, polypyrimidine tract-binding protein (PTB). Conversely, hnRNP K-mediated inhibition was antagonized by the viral 3C protease through the cleavage of hnRNP K at the Glu-364 residue during FMDV infection. Interestingly, the N-terminal cleavage product, hnRNP K(1–364), retained partial inhibitory effects on IRES activity, whereas the C-terminal cleavage product, hnRNP K(364–465), became a positive regulator of FMDV replication. Our findings expand the current understanding of virus-host interactions concerning viral recruitment and the modulation of ITAFs, providing new insights into translational control during viral infection. IMPORTANCE The translation of picornaviral genome RNA mediated by the internal ribosomal entry site (IRES) is a crucial step for virus infections. Virus-host interactions play a critical role in the regulation of IRES-dependent translation, but the regulatory mechanism remains largely unknown. In this study, we identified an ITAF, hnRNP K, that negatively regulates FMDV replication by inhibiting viral IRES-mediated translation. In addition, we describe a novel translational regulation mechanism involving the proteolytic cleavage of hnRNP K by FMDV protease 3C. The cleavage of hnRNP K yields two cleavage products with opposite functions: the cleavage product hnRNP K(1–364) retains a partial inhibitory effect on IRES activity, and the cleavage product hnRNP K(364–465) becomes a positive regulator of FMDV replication. Our findings shed light on the effect of a novel ITAF on the translational regulation of picornavirus and provide new insights into translational control during viral infection.

Our previous study of coxsackievirus B3 (CVB3)-induced unfolded protein responses (UPR) found that overexpression of ATF6a enhances CVB3 VP1 capsid protein production and increases viral particle formation. These findings implicate that ATF6a signalling benefits CVB3 replication. However, the mechanism by which ATF6a signalling is transduced to promote virus replication is unclear. In this study, using a Tet-On inducible ATF6a HeLa cell line, we found that ATF6a signalling downregulated the protein expression of the endoplasmic reticulum (ER) degradation-enhancing α-mannosidase-like protein 1 (EDEM1), resulting in accumulation of CVB3 VP1 protein; in contrast, expression of a dominant negative ATF6a had the opposite effect. Furthermore, we found that EDEM1 was cleaved by both CVB3 protease 3C and virus-activated caspase and subsequently degraded via the ubiquitin-proteasome pathway. However, overexpression of EDEM1 caused VP1 degradation, likely via a glycosylation-independent and ubiquitin-lysosome pathway. Finally, we demonstrated that CRISPR/Cas9-mediated knockout of EDEM1 increased VP1 accumulation and thus CVB3 replication. This is the first study to report the ER protein quality control of non-enveloped RNA virus and reveals a novel mechanism by which CVB3 evades host ER quality control pathways through cleavage and degradation of the UPR target gene EDEM1, to ultimately benefit its own replication.

Previous studies have shown that the FMDV Asia1/YS/CHA/05 high-fidelity mutagen-resistant variants are attenuated (Zeng et al., 2014). Here, we introduced the same single or multiple-amino-acid substitutions responsible for increased 3Dpol fidelity of type Asia1 FMDV into the type O FMDV O/YS/CHA/05 infectious clone. The rescued viruses O-DA and O-DAMM are lower replication fidelity mutants and showed an attenuated phenotype. These results demonstrated that the same amino acid substitution of 3Dpol in different serotypes of FMDV strains had different effects on viral fidelity. In addition, nucleoside analogues were used to select high-fidelity mutagen-resistant type O FMDV variants. The rescued mutagen-resistant type O FMDV high-fidelity variants exhibited significantly attenuated fitness and a reduced virulence phenotype. These results have important implications for understanding the molecular mechanism of FMDV evolution and pathogenicity, especially in developing a safer modified live-attenuated vaccine against FMDV.

Foot-and-mouth disease (FMD), caused by foot-and-mouth disease virus (FMDV), is a highly contagious infectious disease that affects domestic and wild cloven-hoofed animals worldwide. VP2 is a structural protein of FMDV. In this study, an FMDV serotype-independent monoclonal antibody (MAb), 10B10, against the viral capsid protein VP2 was generated, and a series of GST fusion proteins expressing a truncated peptide of VP2 was subjected to Western blot analysis using MAb 10B10. Their results indicated that the peptide 8TLLEDRILT16 of VP2 is the minimal requirement of the epitope recognized by MAb 10B10. Importantly, this linear epitope was highly conserved among all seven serotypes of FMDV in a sequence alignment analysis. Subsequent alanine-scanning mutagenesis analysis revealed that the residues Thr8 and Asp12 of the epitope were crucial for MAb-10B10 binding. Furthermore, Western blot analysis also revealed that the MAb 10B10-directed epitope could be recognized by positive sera from FMDV-infected cattle. The discovery that MAb 10B10 recognizes a serotype-independent linear epitope of FMDV suggests potential applications for this MAb in the development of serotype-independent tests for FMDV.

Senecavirus A (SVA) is associated with vesicular disease in swine and the acute death of neonatal piglets. Here, senecavirus A was isolated from a pig displaying vesicular disease in Northeast China. The virus was designated as SVA/HLJ/CHA/2016 and its full-length nucleotide sequence was determined and analyzed in comparison with other known SVA strains. The complete genome sequence of SVA/HLJ/CHA/2016 shares high nucleotide identities, of 93.8 to 99%, with previously reported SVA full-length genomes. Phylogenetic analysis of both the SVA full-length genomes and the VP1 genes revealed that the SVA/HLJ/CHA/2016 strain is closely related to the 2015 US strains, instead of other China isolates. Our finding provides evidence that SVA infection of pigs has occurred in Northeast China, and the importance of SVA surveillance in China should be emphasized.

The foot-and-mouth disease virus (FMDV) nonstructural protein 3A plays an important role in viral replication, virulence, and host range. It has been shown that deletions of 10 or 19-20 amino acids in the C-terminal half of 3A attenuate serotype O and C FMDVs, which replicate poorly in bovine cells but normally in porcine-derived cells, and the C-terminal half of 3A is not essential for serotype Asia1 FMDV replication in BHK-21 cells. In this study, we constructed a 3A deletion FMDV mutant based on a serotype O FMDV, the wild-type virus O/YS/CHA/05, with a 60-amino acid deletion in the 3A protein sequence, between residues 84 and 143. The rescued virus O/YS/CHA/05-Δ3A exhibited slower growth kinetics and formed smaller plaques compared to O/YS/CHA/05 in both BHK-21 and IBRS-2 cells, indicating that the 60-amino acid deletion in the 3A protein impaired FMDV replication. After 14 passages in BHK-21 cells, the replication capacity of the passaged virus O/YS/CHA/05-Δ3A-P14 returned to a level similar to the wild-type virus, suggesting that amino acid substitutions responsible for the enhanced replication capacity occurred in the genome of O/YS/CHA/05-Δ3A-P14. By sequence analysis, two amino acid substitutions, P153L in VP1 and T135I in 2C, were found in the O/YS/CHA/05-Δ3A-P14 genome compared to the O/YS/CHA/05-Δ3A genome. Subsequently, the amino acid substitutions VP1 P153L and 2C T135I were separately introduced into O/YS/CHA/05-Δ3A to rescue mutant viruses for examining their growth kinetics. Results showed that the 2C T135I instead of the VP1 P153L enhanced the virus replication capacity. The 2C T135I substitution also improved the replication of the wild-type virus, indicating that the effect of 2C T135I substitution on FMDV replication is not associated with the 3A deletion. Furthermore, our results showed that the T135I substitution in the nonstructural protein 2C enhanced O/YS/CHA/05 replication through promoting viral RNA synthesis.

Foot-and-mouth disease (FMD), caused by foot-and-mouth disease virus (FMDV), is a highly contagious infectious disease that affects domestic and wild cloven-hoofed animals worldwide. VP2 is a structural protein of FMDV. In this study, a potent FMDV serotype-independent monoclonal antibody (MAb) 3D9 was generated. Screening of a phage-displayed random 12-peptide library revealed that MAb 3D9 bound to phages displaying a consensus motif GVYxxAYxW that is highly homologous to the 89GVYxxxxxxxAYxxxxW105 motif in the FMDV VP2 protein. Importantly, this conformational epitope was highly conserved among all seven serotypes of FMDV analyzed in sequence alignments. To further verify the authentic epitope recognized by MAb 3D9, a FMDV O/YS/CHA/05 mutant virus V90A was generated using a reverse genetics system. The results revealed that Val90 was an important residue for MAb 3D9 binding within this conformational epitope. Thus, we finely mapped a conserved conformational epitope onto the FMDV VP2 protein. These results could be applied in the development of epitope-based vaccines and suitable MAb-based diagnostic methods for various FMDV serotype-independent tests.

In some legume–rhizobium symbioses, host specificity is influenced by rhizobial type III effectors-nodulation outer proteins (Nops). However, the genes encoding host proteins that interact with Nops remain unknown. In this study, we aimed to identify candidate soybean genes associated with NopD, one of the type III effectors of Sinorhizobium fredii HH103. The results showed that the expression pattern of NopD was analyzed in rhizobia induced by genistein. We also found NopD can be induced by TtsI, and NopD as a toxic effector can induce tobacco leaf death. In 10 soybean germplasms, NopD played a positively effect on nodule number (NN) and nodule dry weight (NDW) in nine germplasms, but not in Kenjian28. Significant phenotype of NN and NDW were identified between Dongnong594 and Charleston, Suinong14 and ZYD00006, respectively. To map the quantitative trait locus (QTL) associated with NopD, a recombinant inbred line (RIL) population derived from the cross between Dongnong594 and Charleston, and chromosome segment substitution lines (CSSLs) derived from Suinong14 and ZYD00006 were used. Two overlapping conditional QTL associated with NopD on chromosome 19 were identified. Two candidate genes were identified in the confident region of QTL, we found that NopD could influence the expression of Glyma.19g068600 (FBD/LRR) and expression of Glyma.19g069200 (PP2C) after HH103 infection. Haplotype analysis showed that different types of Glyma.19g069200 haplotypes could cause significant nodule phenotypic differences, but Glyma.19g068600 (FBD/LRR) was not. These results suggest that NopD promotes S. fredii HH103 infection via directly or indirectly regulating Glyma.19g068600 and Glyma.19g069200 expression during the establishment of symbiosis between rhizobia and soybean plants.

The roles of lncRNAs in the infection of enteroviruses have been barely demonstrated. In this study, we used coxsackievirus B3 (CVB3), a typical enterovirus, as a model to investigate the expression profiles and functional roles of lncRNAs in enterovirus infection. We profiled lncRNAs and mRNA expression in CVB3-infected HeLa cells by lncRNA-mRNA integrated microarrays. As a result, 700 differentially expressed lncRNAs (431 up-regulated and 269 down-regulated) and 665 differentially expressed mRNAs (299 up-regulated and 366 down-regulated) were identified in CVB3 infection. Then we performed lncRNA-mRNA integrated pathway analysis to identify potential functional impacts of the differentially expressed mRNAs, in which lncRNA-mRNA correlation network was built. According to lncRNA-mRNA correlation, we found that XLOC-001188, an lncRNA down-regulated in CVB3 infection, was negatively correlated with NFAT5 mRNA, an anti-CVB3 gene reported previously. This interaction was supported by qPCR detection following siRNA-mediated knockdown of XLOC-001188, which showed an increase of NFAT5 mRNA and a reduction of CVB3 genomic RNA. In addition, we observed that four most significantly altered lncRNAs, SNHG11, RP11-145F16.2, RP11-1023L17.1 and RP11-1021N1.2 share several common correlated genes critical for CVB3 infection, such as BRE and IRF2BP1. In all, our studies reveal the alteration of lncRNA expression in CVB3 infection and its potential influence on CVB3 replication, providing useful information for future studies of enterovirus infection. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1007/s12250-019-00152-x) contains supplementary material, which is available to authorized users.

Senecavirus A (SVA) is a reemerging virus, and recent evidence has emphasized the importance of SVA recombination in vivo on virus evolution. In this study, we report the development of an infectious cDNA clone for the SVA/HLJ/CHA/2016 strain. We used this strain to develop a reporter virus expressing enhanced green fluorescent protein (eGFP), which we then used to screen for a recombination-deficient SVA by an eGFP retention assay. Sequencing of the virus that retained the eGFP following passage allowed us to identify the nonsynonymous mutations (S460L alone and I212V-S460L in combination) in the RNA-dependent RNA polymerase (RdRp) region of the genome. We developed a Senecavirus-specific cell culture-based recombination assay, which we used to elucidate the role of RdRp in SVA recombination. Our results demonstrate that these two polymerase variants (S460L and I212/S460L) have reduced recombination capacity. These results indicate that the RdRp plays a central role in SVA replicative recombination. Notably, our results showed that the two recombination-deficient variants have higher replication fidelity than the wild type (WT) and display decreased ribavirin sensitivity compared to the WT. In addition, these two mutants exhibited significantly increased fitness in vitro compared to the WT. These results demonstrate that recombination and mutation rates are intimately linked. Our results have important implications for understanding the crucial role of the RdRp in virus recombination and fitness, especially in the molecular mechanisms of SVA evolution and pathogenicity. IMPORTANCE Recent evidence has emphasized the importance of SVA recombination on virus evolution in vivo. We describe the first assays to study Senecavirus A recombination. The results show that the RNA-dependent RNA polymerase plays a crucial role in recombination and that recombination can impact the fitness of SVA in cell culture. Further, SVA polymerase fidelity is closely related to recombination efficiency. The results provide key insights into the role of recombination in positive-strand RNA viruses.

In the current machine learning methods, deep learning is the focus of attention. Deep learning technology has achieved rapid development in various related fields, especially in the field of face recognition applications. Deep learning is to imitate the mechanism of the human neural perception system by layer-by-layer autonomous learning to obtain high-level abstract features, which can solve the distribution of facial changes, with fast learning speed and high recognition accuracy. This article introduces the advantages and core technologies of face deep learning, and studies and analyzes the application of face deep learning technology in university management.

The nuclear factor of activated T cells 5 (NFAT5) is well known for its sensitivity to cellular osmolarity changes, such as in the kidney medulla. Accumulated evidence indicates that NFAT5 is also a sensitive factor to stress signals caused by non-hypertonic stimuli such as heat shock, biomechanical stretch stress, ischaemia, infection, etc. These osmolality-related and -unrelated stimuli can induce NFAT5 upregulation, activation and nuclear accumulation, leading to its protective role against various detrimental effects. However, dysregulation of NFAT5 expression may cause pathological conditions in different tissues, leading to a variety of diseases. These protective or pathogenic effects of NFAT5 are dictated by the regulation of its target gene expression and activation of its signalling pathways. Recent studies have found a number of kinases that participate in the phosphorylation/activation of NFAT5 and related signal proteins. Thus, this review will focus on the NFAT5-mediated signal transduction pathways. As for the stimuli that upregulate NFAT5, in addition to the stresses caused by hyperosmotic and non-hyperosmotic environments, other factors such as miRNA, long non-coding RNA, epigenetic modification and viral infection also play an important role in regulating NFAT5 expression; thus, the discussion in this regard is another focus of this review. As the heart, unlike the kidneys, is not normally exposed to hypertonic environments, studies on NFAT5-mediated cardiovascular diseases are just emerging and rapidly progressing. Therefore, we have also added a review on the progress made in this field of research.

The effective population inversion of 2 H11/2 from 4 S3/2 state of Er3+ ions can be achieved through the annihilation of phonons; random lasing action from BLF films embedded with Yb3+ /Er3+ codoped BLF nanocrystals is demonstrated and high ambient temperature (>433 K) operation lasers with a very low excitation threshold (

The 5' untranslated region (5'UTR) of foot-and-mouth disease virus (FMDV) contains an internal ribosome entry site (IRES) that facilitates translation initiation of the viral ORF in a 5' (m7GpppN) cap-independent manner. IRES elements are responsible for the virulence phenotypes of several enteroviruses. Here, we constructed a chimeric virus in which the IRES of FMDV was completely replaced with that of bovine rhinitis B virus (BRBV) in an infectious clone of serotype O FMDV. The resulting IRES-replaced virus, FMDV(BRBV), replicated as efficiently as WT FMDV in hamster-derived BHK-21 cells, but was restricted for growth in porcine-derived IBRS-2, PK-15 and SK-6 cells, which are susceptible to WT FMDV. To identify the genetic determinants of FMDV underlying this altered cell tropism, a series of IRES-chimeric viruses were constructed in which each domain of the FMDV IRES was replaced with its counterpart from the BRBV IRES. The replication kinetics of these chimeric viruses in different cell lines revealed that the growth restriction phenotype in porcine-derived cells was produced after the replacement of domain 3 or 4 in the FMDV IRES. Furthermore, the change in FMDV cell tropism due to IRES replacement in porcine-derived cells was mainly attributed to a decline in cell-specific IRES translation initiation efficiency. These findings demonstrate that IRES domains 3 and 4 of FMDV are novel cell-specific cis-elements for viral replication in vitro and suggest that IRES-mediated translation determines the species specificity of FMDV infection in vivo.

This paper summarizes the background of the construction of campus video security monitoring system, points out that deep learning has an important impact on the development of campus security monitoring system, and puts forward the design principles and ideas of campus video security system. On the whole, the architecture of campus security monitoring system is constructed. The application of deep learning algorithm to campus security monitoring system will realize the precision of campus security management, improve the ability of campus security emergency command and decision, realize the intelligence of campus security operation, improve the efficiency of campus security work, improve the level of campus security management, and ensure the campus more safe and stable.

College physics course based on online teaching system can make the boring theoretical derivation process more intuitive and convenient with the help of the unique characteristics of multimedia technology and tools, so that students’ learning efficiency can be significantly improved, so it has high research value. Based on this, this paper first analyses the current situation and existing problems of college physics course teaching, then studies the necessity of constructing college physics online teaching platform, and finally gives the construction strategy of college physics online teaching system based on the construction of curriculum group.

With the continuous development of computer information technology, the DISLab system based on computer technology can effectively transform many abstract physical measurement parameters in college physics teaching into physical quantities that can be measured in real time with the help of computers, sensors and other software and hardware equipment, so it has been more and more widely studied and applied in physical experiments. Based on this, this paper first analyzes the application status and problems of DISLab device in college physics experiment teaching, then studies the necessity of DISLab in college physics experiment teaching, and finally analyzes the relationship between computer DISLab device and college physics experiment teaching.

The background and foundation of applying big data analysis to mobile communication network planning is precisely the current rapid growth of network data and the update and development of big data technology. With the help of big data analysis tools, based on the current communication network, planning goals, it can be more comprehensive Analyze and explore the value perception and behavior trajectory of network users, etc., so as to determine the market demand trend, formulate a more scientific and reasonable planning program. In short, the purpose of the application of big data in communication network, planning is to promote the healthy development of the network. The cellular wireless positioning algorithm that realizes TDOA positioning technology by using big data is a relatively important technology, which is studied in this paper.

In this study, ten sites on the N terminus and different surface variable regions (VRs) of the bovine parvovirus (BPV) VP2 capsid protein were selected according to an alignment of its sequence with that of the BPV-1 strain HADEN for insertion of the type O foot-and-mouth disease virus (FMDV) conserved neutralizing epitope 8E8. Ten epitope-chimeric BPV VP2 capsid proteins carrying the 8E8 epitope were expressed in Sf9 cells, and electron micrographs demonstrated that these fusion proteins self-assembled into virus-like particles (VLPs) with properties similar to those of natural BPV virions. Immunofluorescence assay (IFA) and Western blot analysis demonstrated that each of the ten epitope-chimeric VLPs reacted with both anti-BPV serum and anti-type O FMDV mAb 8E8. These results indicated that insertions of the 8E8 epitope at these sites on the BPV VP2 protein did not interfere with the immunoreactivity of VP2 or VLP formation, and that the exogenous epitope 8E8 was correctly expressed in BPV VLPs. In addition, anti-BPV IgG antibodies were induced in mice by intramuscular inoculation with each of the ten chimeric VLPs, indicating that the immunogenicity of the chimeric VLPs was not disrupted. Importantly, potent anti-FMDV viral neutralizing (VN) antibodies, which exhibited the highest titre of 1 : 176, were induced by two chimeric VLPs, rBPV-VLP-8E8(391) and rBPV-VLP-8E8(395), in which the 8E8 epitope was inserted into positions 391/392 and 395/396, respectively, in the VR VIII of BPV VP2. Our results demonstrated that the 391/392 and 395/396 positions in the VR VIII of the BPV VP2 protein can effectively display a foreign epitope, making this an attractive approach for the design of nanoparticle-vectored and epitope-based vaccines.

Intercalated discs (ICDs) are highly orchestrated structures that connect neighboring cardiomyocytes in the heart. Three major complexes are distinguished in ICD: desmosome, adherens junction (AJ), and gap junction (GJ). Desmosomes are major cell adhesion junctions that anchor cell membrane to the intermediate filament network; AJs connect the actin cytoskeleton of adjacent cells; and gap junctions metabolically and electrically connect the cytoplasm of adjacent cardiomyocytes. All these complexes work as a single unit, the so-called area composita, interdependently rather than individually. Mutation or altered expression of ICD proteins results in various cardiac diseases, such as ARVC (arrhythmogenic right ventricular cardiomyopathy), dilated cardiomyopathy, and hypotrophy cardiomyopathy, eventually leading to heart failure. In this article, we first review the recent findings on the structural organization of ICD and their functions and then focus on the recent advances in molecular pathogenesis of the ICD-related heart diseases, which include two major areas: i) the ICD gene mutations in cardiac diseases, and ii) the involvement of ICD proteins in signal transduction pathways leading to myocardium remodeling and eventual heart failure. These major ICD-related signaling pathways include Wnt/β-catenin pathway, p38 MAPK cascade, Rho-dependent serum response factor (SRF) signaling, calcineurin/NFAT signaling, Hippo kinase cascade, etc., which are differentially regulated in pathological conditions.

Multiphoton pumped stimulated emission requires simultaneous absorption of photons for the creation of population inversion to sustain optical amplification. Recently, stimulated emission by simultaneous absorption of up to five photons has been realized. To achieve more diverse nonlinear optical applications, it is desired to have more photons involved in the upconversion process. Here, we demonstrate unambiguously frequency upconverted amplified spontaneous emission and lasing via simultaneous six-photon absorption from inorganic perovskite. Our finding allows the utilization of inorganic perovskite as the novel alternative for higher-order multiphoton fluorescent applications.

CVB3 (coxsackievirus 3) is a primary causal agent of viral myocarditis. Emodin is a natural compound isolated from certain plant roots. In the present study, we found that emodin inhibited CVB3 replication in vitro and in mice, and now we report an unrecognized mechanism by which emodin inhibits CVB3 replication through suppression of viral protein translation via multiple pathways. On one hand, emodin treatment inhibited Akt/mTOR (mammalian target of rapamycin) signalling and activated 4EBP1 (eukaryotic initiation factor 4R-binding protein 1), leading to suppression of translation initiation of ribosomal protein L32 encoded by a 5′-TOP (terminal oligopyrimidine) mRNA. On the other hand, emodin treatment differentially regulated multiple signal cascades, including Akt/mTORC1/p70S6K (p70 S6 kinase), ERK1/2 (extracellular-signal-regulated kinase 1/2)/p90RSK (p90 ribosomal S6 kinase) and Ca2+/calmodulin, leading to activation of eEF2K (eukaryotic elongation factor 2 kinase) and subsequent inactivation of eEF2 (eukaryotic elongation factor 2), resulting in inhibition of CVB3 VP1 (viral protein 1) synthesis. These data imply that eEF2K is a major factor mediating cross-talk of different arms of signalling cascades in this signal network. This notion was verified by either overexpressing eEF2K or treating the cells with siRNAs or eEF2K inhibitor A484954. We showed further that the emodin-induced decrease in p70S6K phosphorylation plays a dominant positive role in activation of eEF2K and in turn in conferring the antiviral effect of emodin. This finding was further solidified by expressing constitutively active and dominant-negative Akt. Collectively, our data reveal that emodin inhibits viral replication through impairing translational machinery and suppression of viral translation elongation.

Viral myocarditis remains a prominent infectious-inflammatory disease for patients throughout the lifespan. The condition presents several challenges including varied modes of clinical presentation, a range of timepoints when patients come to attention, a diversity of approaches to diagnosis, a spectrum of clinical courses, and unsettled perspectives on therapeutics in different patient settings and in the face of different viral pathogens. In this review, we examine current knowledge about viral heart disease and especially provide information on evolving understanding of mechanisms of disease and efforts by investigators to identify and evaluate potential therapeutic avenues for intervention.

Cleavage of eukaryotic translation initiation factor 4G (eIF4G) by enterovirus proteases during infection leads to the shutoff of cellular cap-dependent translation, but does not affect the initiation of cap-independent translation of mRNAs containing an internal ribosome entry site (IRES). Death-associated protein 5 (DAP5), a structural homolog of eIF4G, is a translation initiation factor specific for IRES-containing mRNAs. Coxsackievirus B3 (CVB3) is a positive single-stranded RNA virus and a primary causal agent of human myocarditis. Its RNA genome harbors an IRES within the 5′-untranslated region and is translated by a cap-independent, IRES-driven mechanism. Previously, we have shown that DAP5 is cleaved during CVB3 infection. However, the protease responsible for cleavage, cleavage site and effects on the translation of target genes during CVB3 infection have not been investigated. In the present study, we demonstrated that viral protease 2A but not 3C is responsible for DAP5 cleavage, generating 45- and 52-kDa N- (DAP5-N) and C-terminal (DAP5-C) fragments, respectively. By site-directed mutagenesis, we found that DAP5 is cleaved at amino acid G434. Upon cleavage, DAP5-N largely translocated to the nucleus at the later time points of infection, whereas the DAP5-C largely remained in the cytoplasm. Overexpression of these DAP5 truncates demonstrated that DAP5-N retained the capability of initiating IRES-driven translation of apoptosis-associated p53, but not the prosurvival Bcl-2 (B-cell lymphoma 2) when compared with the full-length DAP5. Similarly, DAP5-N expression promoted CVB3 replication and progeny release; on the other hand, DAP5-C exerted a dominant-negative effect on cap-dependent translation. Taken together, viral protease 2A-mediated cleavage of DAP5 results in the production of two truncates that exert differential effects on protein translation of the IRES-containing genes, leading to enhanced host cell death.