Inducing Circularly Polarized Luminescence by Confined Synthesis of Ultrasmall Chiral Carbon Nanodot Arrays in Pyrene-Based MOF Thin Film.

Combining the features of the host-guest system and chirality is an efficient strategy to achieve circularly polarized luminescence (CPL). Herein, well-defined chiral carbon nanodot (chirCND) arrays were confined-synthesized by low-temperature calcination of a chiral amino acid loaded metal-organic framework (MOF) to induce high CPL. An achiral porous pyrene-based MOF NU-1000 thin film as the host template was prepared by a liquid-phase epitaxial layer-by-layer fashion, and chiral amino acids as the carbon sources could be confined in the porous MOF and carbonized to homogeneous and ultrasmall chirCND arrays, resulting in a chirCNDs@NU-1000 thin film (l-CNDsx@NU-1000; x = l-cysteine (cys), l-serine, l-histidine, l-glutamic acid, and l-pyroglutamic acid). The results show the pristine chirCNDs by directly carbonizing chiral amino acids hardly endow them with a CPL property. By contrast, benefiting from the arrayed confinement and coordination interaction between chirCNDs and NU-1000, the chirality transfer on the excited state of chirCNDs@NU-1000 is enabled, leading to strong CPL performance (a high luminescence dissymmetry factor glum of l-CNDscys@NU-1000 thin film reached 1.74 × 10-2). This study of chirCNDs encapsulated in fluorescent MOF thin films provides a strategy for developing uniform chiral carbon nanoarrays and offers chiral host-guest thin-film materials for optical applications.

Gas-template directed in situ synthesis of highly nitrogen-doped carbon nanotubes with superior sulfur compatibility and enhanced functionalities.

Herein, we develop a low temperature gas template route for in situ growth of highly nitrogen-doped (5.68 wt%), multi-walled carbon nanotubes (N-MWCNTs). The N-MWCNTs exhibit superior sulfur compatibility in hydrogen sulfide (H2S) resource utilization, thus resulting in their enhanced functionality as Li-S cathodes with high sulfur-specific capacity and retention rate.

Efficiently Integrated Desulfurization from Natural Gas over Zn-ZIF-Derived Hierarchical Lamellar Carbon Frameworks.

Selective removal of carbonyl sulfide (COS) and hydrogen sulfide (H2S) is the key step for natural gas desulfurization due to the highly toxic and corrosive features of these gaseous sulfides, and efficient and stable desulfurizers are urgently needed in the industry. Herein, we report a class of nitrogen-functionalized, hierarchically lamellar carbon frameworks (N-HLCF-xs), which are obtained from the structural transformation of Zn zeolitic imidazolate frameworks via controllable carbonization. The N-HLCF-xs possess the desirable characteristics of large Brunauer-Emmett-Teller surface areas (645-923 m2/g), combined primary three-dimensional microporosity and secondary two-dimensional lamellar microstructure, and high density of nitrogen base sites with enhanced pyridine ratio (17.52 wt %, 59.91%). The anchored nitrogen base sites in N-HLCF-xs show improved accessibility, which boosts their interaction with acidic COS and H2S. As expected, N-HLCF-xs can be employed as multifunctional and efficient desulfurizers for selective removal of COS and H2S from natural gas. COS was first transformed into H2S via catalytic hydrolysis, and the produced H2S was then captured and separated and catalyzed oxidation into elemental sulfur. The above continuous processes can be achieved with solo N-HLCF-xs, giving extremely high efficiencies and reusability. Their integrated desulfurization performance was better than many desulfurizers used in the area, such as activated carbon, ß zeolite, MIL-101(Fe), K2CO3/γ-Al2O3, and FeOx/TiO2.

Porcine Reproductive and Respiratory Syndrome Virus Structural Protein GP3 Regulates Claudin 4 To Facilitate the Early Stages of Infection.

Claudins (CLDN) are a family of proteins that represent the most important components of tight junctions, where they establish the paracellular barrier that controls the flow of molecules in the intercellular space between epithelial cells. Several types of viruses make full use of CLDN to facilitate entry into cells. Porcine reproductive and respiratory syndrome virus (PRRSV) is one of the most important pathogens in the swine industry. In this study, we found that CLDN4 functions as an anti-PRRSV factor by blocking its absorption during the early stages of infection. The small extracellular loop (ECL2) of CLDN4 restricted the viral particles outside cells by binding to GP3. A novel function of GP3-mediated regulation of CLDN4 transcription was suggested. CLDN4 can be decreased through downregulating the level of CLDN4 transcription by ubiquitinating the transcription factor, SP1. The mechanism by which highly pathogenic PRRSV infects the epithelium was proposed. Importantly, ECL2 was found to block PRRSV absorption and infection and neutralize the virus. A more in-depth understanding of PRRSV infection is described, and novel therapeutic antiviral strategies are discussed.IMPORTANCE In the present study, the role of CLDN4 in PRRSV infection was studied. The results showed that CLDN4 blocked absorption into cells and restricted extracellular viral particles via the interaction between the CLDN4 small extracellular loop, ECL2, and the viral surface protein GP3. GP3 was found to downregulate CLDN4 through ubiquitination of the transcription factor SP1 to facilitate viral entry. The mechanism by which highly pathogenic PRRSV infects the epithelium is suggested. A novel function of GP3 in regulating gene transcription was discovered. Moreover, ECL2 could block PRRSV absorption and infection, as well as neutralizing the virus in the supernatant, which may lead to the development of novel therapeutic antiviral strategies.

Prevalent Eurasian avian-like H1N1 swine influenza virus with 2009 pandemic viral genes facilitating human infection.

Pigs are considered as important hosts or "mixing vessels" for the generation of pandemic influenza viruses. Systematic surveillance of influenza viruses in pigs is essential for early warning and preparedness for the next potential pandemic. Here, we report on an influenza virus surveillance of pigs from 2011 to 2018 in China, and identify a recently emerged genotype 4 (G4) reassortant Eurasian avian-like (EA) H1N1 virus, which bears 2009 pandemic (pdm/09) and triple-reassortant (TR)-derived internal genes and has been predominant in swine populations since 2016. Similar to pdm/09 virus, G4 viruses bind to human-type receptors, produce much higher progeny virus in human airway epithelial cells, and show efficient infectivity and aerosol transmission in ferrets. Moreover, low antigenic cross-reactivity of human influenza vaccine strains with G4 reassortant EA H1N1 virus indicates that preexisting population immunity does not provide protection against G4 viruses. Further serological surveillance among occupational exposure population showed that 10.4% (35/338) of swine workers were positive for G4 EA H1N1 virus, especially for participants 18 y to 35 y old, who had 20.5% (9/44) seropositive rates, indicating that the predominant G4 EA H1N1 virus has acquired increased human infectivity. Such infectivity greatly enhances the opportunity for virus adaptation in humans and raises concerns for the possible generation of pandemic viruses.

Fowl adenovirus serotype 4-induced apoptosis, autophagy, and a severe inflammatory response in liver.

Fowl adenovirus serotype 4 (FAdV-4) is a hepatotrophic virus that causes severe liver diseases. Upon histological examination, the most remarkable findings in the liver are small multifocal areas of necrosis and mononuclear cell infiltration, including basophilic intranuclear inclusion bodies in hepatocytes surrounded by a clear halo or which fill the entire nucleus. Here, we examined the mechanism responsible for FAdV-4-mediated hepatocyte damage in vivo and in vitro. The results showed that FAdV-4 impaired liver integrity and function, which decreased albumin and blood glucose concentrations and increased the plasma activity of aspartate aminotransferase and lactate dehydrogenase, compared with a non-infected control group (P<0.05). FAdV-4 induced hepatocyte apoptosis in a time-dependent manner in vivo and in vitro. Additionally, we found that FAdV-4 also induced the autophagy of hepatocytes, which promoted the conversion of microtubule-associated protein light chain 3 (LC3-I) to LC3-II, which is a hallmarks of autophagy. Furthermore, the mRNA expressions of interleukin (IL)-1ß, IL-6, IL-8, and tumor necrosis factor (TNF)-α in vivo and in vitro showed a statistically significant increase (P<0.05) compared to that of the control group. However, the molecular mechanisms underlying the FAdV-4-induced apoptotic and autophagic cell death remain unclear. In summation, our observations suggested that FAdV-4 induced liver injury via apoptosis, autophagy, and a severe inflammatory response.

Florfenicol-induced Mitochondrial Dysfunction Suppresses Cell Proliferation and Autophagy in Fibroblasts.

Florfenicol (FLO) is one of the most popular antibiotics used in veterinary clinic and aquaculture. FLO can inhibit both bacterial and mitochondrial protein synthesis. However, the effects of FLO on mitochondrial function and cellular homeostasis remain unclear. Here we show that FLO inhibits expression of mitochondrial DNA-encoded proteins, decreases mitochondrial membrane potential, and promotes generation of reactive oxygen species (ROS) in vitro. As a result, activities of mitochondrial respiratory chain complex I and IV and the cellular ATP level are decreased and mitochondrial morphology is damaged. FLO represses cell growth and proliferation by suppression of phosphorylation of p70S6K through AMPK/mTOR/p70S6K pathway. Furthermore, FLO also induces G0/G1 cell cycle arrest via increase of p21 levels through activating ROS/p53/p21 pathway. Moreover, the clearance of damaged mitochondria by autophagy is impaired, leading to cell proliferation inhibition and promotes cell senescence. In addition, FLO-induced upregulation of cytosolic p53 may contribute to mitophagy deficiency via regulation of Parkin recruitment. In summary, our data suggest that florfenicol is an inhibitor of mitochondrial protein synthesis that can induce noticeable cytotoxicity. Thus, these findings can be useful for guiding the proper use of FLO and the development of safe drugs.

Pathogenicity and immunosuppressive potential of fowl adenovirus in specific pathogen free chickens.

To elucidate the effect of fowl adenovirus (FAdV)-C in specific-pathogen-free (SPF) chickens, we investigated the pathogenicity, body weights, enzymatic systems, and immune organs of chickens in response to Newcastle disease virus (NDV) and avian influenza virus subtype H9 (AIV-H9) vaccination. Chickens were divided randomly into four groups, which included injection groups (FAdV-C, vaccination, and FAdV-C plus vaccination) and a negative control group. The results indicated that FAdV-C was highly pathogenic in SPF chickens and led to a 40% mortality rate and growth retardation, compared with the control birds. Significant changes in clinical chemical markers of all infected birds, together with histopathological lesions, indicated impairment of the liver and heart integrity and function. Furthermore, chickens in the FAdV-C plus vaccination group had significantly lower titers of antibodies against NDV and AIV-H9 than the uninfected and vaccinated chickens. The results of this study provide new insights into the pathogenesis of hydropericardium syndrome, a disease that progresses to a metabolic disorder and causes serious growth retardation and immunosuppression.

Hydropericardium syndrome outbreak caused by fowl adenovirus serotype 4 in China in 2015.

There have been many outbreaks of hydropericardium syndrome (HPS), which is characterized by pericardial effusion and hepatitis, in Chinese chicken farms since June 2015. HPS was mainly found in miscellaneous meat-type chickens, Ma chickens, layer chicks and Three-yellow chickens, while it was occasionally found in white broilers. To determine the specific causative pathogen and pathogenicity of HPS in chickens, we collected 25 suspected cases and performed clinical pathology and aetiology analyses. The results showed that the 25 cases exhibited multifocal hepatitis with intra-nuclear inclusion bodies and 70 nm-latticed viral particles in the cell nuclei. All samples were positive for fowl adenovirus (FAdV), and sequencing results showed that the hexon gene shared the highest nucleotide similarities with the hexon gene of group 1 serotype 4 (FAdV-4). FAdV-4 was highly pathogenic to embryos and specific pathogen-free chickens, causing 100 and 70 % mortality rates, respectively. Thus, FAdV-4 is associated with HPS outbreaks in China.

MYH9 is an Essential Factor for Porcine Reproductive and Respiratory Syndrome Virus Infection.

Porcine reproductive and respiratory syndrome (PRRS) caused by the PRRS virus (PRRSV) is an important swine disease worldwide. PRRSV has a limited tropism for certain cells, which may at least in part be attributed to the expression of the necessary cellular molecules serving as the virus receptors or factors on host cells for virus binding or entry. However, these molecules conferring PRRSV infection have not been fully characterized. Here we show the identification of non-muscle myosin heavy chain 9 (MYH9) as an essential factor for PRRSV infection using the anti-idiotypic antibody specific to the PRRSV glycoprotein GP5. MYH9 physically interacts with the PRRSV GP5 protein via its C-terminal domain and confers susceptibility of cells to PRRSV infection. These findings indicate that MYH9 is an essential factor for PRRSV infection and provide new insights into PRRSV-host interactions and viral entry, potentially facilitating development of control strategies for this important swine disease.

Characterization of the Interactome of the Porcine Reproductive and Respiratory Syndrome Virus Nonstructural Protein 2 Reveals the Hyper Variable Region as a Binding Platform for Association with 14-3-3 Proteins.

Porcine reproductive and respiratory syndrome virus (PRRSV) is a major threat to the swine industry worldwide and hence global food security, exacerbated by a newly emerged highly pathogenic (HP-PRRSV) strain from China. PRRSV nonstructural protein 2 (nsp2) is a multifunctional polypeptide with strain-dependent influences on pathogenicity. A number of discrete functional regions have been identified on the protein. Quantitative label free proteomics was used to identify cellular binding partners of nsp2 expressed by HP-PRRSV. This allowed the identification of potential cellular interacting partners and the discrimination of nonspecific interactions. The interactome data were further investigated and validated using biological replicates and also compared with nsp2 from a low pathogenic (LP) strain of PRRSV. Validation included both forward and reverse pulldowns and confocal microscopy. The data indicated that nsp2 interacted with a number of cellular proteins including 14-3-3, CD2AP, and other components of cellular aggresomes. The hyper-variable region of nsp2 protein was identified as a binding platform for association with 14-3-3 proteins.

Synthesis of La-Co-O Mixed Oxides via Polyethylene Glycol-Assisted Co-Precipitation Method for Total Oxidation of Benzene.

La-Co-O mixed oxides (LCO) were prepared by co-precipitation method with the presence of polyethylene glycol (PEG) as dispersant. The influence of adding different molecular weight of PEG (0, 2 000, 6 000, 20 000 g·mol-1) on the physicochemical and catalytic properties of La-Co-O mixed oxides for total oxidation of benzene was investigated. The samples were characterized by means of N2 physical adsorption, X-ray diffraction (XRD), scanning electron microscopy (SEM), temperature-programmed reduction by H2 (H2-TPR), temperature-programmed desorption of O2 (O2-TPD), and X-ray photoelectron spectroscopy (XPS). The order of catalytic activity was found to be LCO-PEG6000>LCO>LCO-PG20000>LCO-PG2000. Particularly, LCO-PEG6000 exhibited benzene conversion of 99% at temperature as low as 383 ℃, which was 126 ℃ lower than that of LCO. The characterization result reveals that all samples had a BET surface area of about 9～10 m2·g-1. The XRD result shows that on all samples LaCoO3 perovskite was mainly formed together with a small amount of La2O3 and Co3O4. The addition of PEG was favorable for the formation of LaCoO3 perovskite. Particularly, the addition of PEG-6000 effectively suppressed the agglomeration of LaCoO3 perovskite, giving rise to small and uniform particles as observed by SEM. Moreover, the results of H2-TPR and O2-TPD indicate that the obtained La-Co-O mixed oxides showed higher reducibility and lattice oxygen mobility, and the Co 2p XPS analysis suggests that more surface Co3+ active species were presented by the addition of PEG-6000. These properties are thought to contribute to the high activity in benzene total oxidation.

Distribution of highly pathogenic porcine reproductive and respiratory syndrome virus (HP-PRRSV) in different stages of gestation sows: HP-PRRSV distribution in gestation sows.

Highly pathogenic PRRSV (HP-PRRSV) emerged in China in 2006 and caused severe reproductive losses, particularly in late-term sows. To determine whether these reproductive failures were related to the susceptibility of late-term sows to HP-PRRV, 60- and 90-days of gestation sows were infected with HP-PRRSV isolate TA-12 (GenBank accession HQ417620). A monoclonal antibody specific to the C-terminal of the nucleocapsid protein was used to evaluate viral distribution by IHC. This showed that HP-PRRSV had a similar distribution in both sets of sows. However, HP-PRRSV infection led to dramatically decreased serum levels of luteinizing hormone (LH) and 17-ß-estradiol (E2) in late-term sows, while only E2 was decreased in the 60-day sows. These results indicate that HP-PRRSV-induced reproductive failure is more likely due to reproductive hormone level imbalances rather than tissue tropism differences.

Design and construction of a chimeric multi-epitope gene as an epitope-vaccine strategy against ALV-J.

In the present study, we designed and constructed a chimeric multi-epitope gene of ALV-J to develop a potential multi-epitope vaccine using a reverse vaccinology approach. The chimeric gene includes 4 multi-epitope concentrated fragments (Gag (278-376aa), Pol (784-855aa), Env (Gp85:145-156aa and Gp37:412-538aa) screened from major structural proteins of ALV-J using epitope prediction software. The recombinant chimeric multi-epitope protein (rCMEPX) encoded by the cloned chimeric gene was successfully expressed using an Escherichia coli expression system. The rCMEPX was induced optimally at 37°C for 4.0 h with 0.5mM IPTG. The identity and purity of the expressed rCMEPX was analyzed on a SDS-PAGE. The specific recognition of the purified rCMEPX by the chicken anti-ALV-J serum on a western analysis demonstrated a good immunoreactivity of the expressed rCMEPX, which indicates that the construction and expression of the multi-epitope based chimeric gene for ALV-J vaccine development is successful. The antigenicity and reactionogenicity of the rCMEPX were evaluated by western blot and indirect ELISA. Our results showed good reactionogenicity, specificity, and sensitivity for the expressed rCMEPX, suggesting that it may be a promising vaccine candidate against ALV-J infections.

Characterization of antigenic domains and epitopes in the ORF3 protein of a Chinese isolate of avian hepatitis E virus.

Avian hepatitis E virus (HEV) is an emerging virus associated with the big liver and spleen disease or hepatitis-splenomegaly syndrome in chickens and subclinical infections by the virus are also common. The complete genome of avian HEV contains three open-reading frames (ORFs) in which ORF2 protein is part of virus particles and thus contains primary epitopes. Antigenic epitopes of avian HEV ORF2 protein have been described but those associated with the ORF3 have not. To analyze the antigenic domains and epitopes in the ORF3 protein of a Chinese isolate of avian HEV (CaHEV), we generated a series of antigens comprised of the complete ORF3 and also five truncated overlapping ORF3 peptides. The antibodies used in this study were mouse antisera and monoclonal antibodies against ORF3, positive chicken sera from Specific Pathogen Free chickens experimentally infected with CaHEV and clinical chicken sera. Using these antigens and antibodies, we identified three antigenic domains at amino acids (aa) 1-28, 55-74 and 75-88 in which aa 75-88 was a dominant domain. The dominant domain contained at least two major epitopes since field chickens infected with avian HEV produced antibodies against the domain and epitopes. These results provide useful information for future development of immunoassays for the diagnosis of avian HEV infection.

Haemangiomas, leiomyosarcoma and myeloma caused by subgroup J avian leukosis virus in a commercial layer flock.

An outbreak of simultaneously occurring haemangiomas, leiomyosarcoma and myeloma was observed in a commercial layer flock in China. The sick chickens were extremely thin and dehydrated. Scattered haemangiomas were found on the claws, breast and wings. At necropsy, haemangiomas and some other nodular tumours were also found in the internal organs. In addition, diffuse enlargement of the liver and spleen appeared in some birds. Histopathologically, haemangiomas were typically cavernous haemangiomas and haemangioendothelioma. In the diffusely swollen liver and spleen, multifocal or widespread marrow tumour cells filled with ball-like acidophilic particles in cytosol were observed, which are the characteristic pathological changes of avian myelocytomatosis. The nodular tumour cells formed by muscle bundles were of variable size, irregular shape, poorly differentiated and malaligned. Immunohistochemistry for vimentin, cytokeratin, actin (smooth muscle) and actin (sarcomeric) and Masson's staining confirmed the different cell lineage of the nodular tumour, thus leading to the diagnosis of leiomyosarcoma. The seroprevalence of avian leukosis subgroup J (ALV-J) antibodies was 13.46% (7/52), while ALV-A/B and reticuloendotheliosis virus (REV) antibodies were not detectable. The DF-1 cells inoculated by virus extracted from liver samples from 24 infected chickens were cultured and the group-specific antigen (GSA) was identified by ELISA. All samples were positive for ALV, which was further identified as ALV-J by immunofluorescence assay (IFA). PCR analysis revealed that three isolates of ALV-J proviral sequence were close to the HPRS-103 prototype strain and other Chinese field strains isolated in recent years, while one isolate (DP01) had a lower homology with them. This is the first report that ALV-J infection caused the simultaneous occurrence of haemangiomas, leiomyosarcoma and myeloma in a commercial layer flock.

Generation of internal image monoclonal anti-idiotypic antibodies against idiotypic antibodies to GP5 antigen of porcine reproductive and respiratory syndrome virus.

Syngeneic monoclonal anti-idiotypic antibodies (Mab2s) were generated against idiotypic antibodies to membrane glycoprotein GP5 of porcine reproductive and respiratory syndrome virus (PRRSV) using the sequential immunization method. Six of 12 Mab2s possessed potential internal image characteristics by recognizing a common idiotype on murine and swine anti-GP5 antibodies. Further serological characterization demonstrated that one of the Mab2 (Mab2-5G2) represents internal image anti-idiotope which mimicked the GP5 antigen that inhibited the interaction between idiotypic anti-GP5 antibodies and GP5 antigen, its reaction with the idiotypic anti-GP5 antibody was inhibited by GP5 antigen and detected the common Id on anti-PRRSV antibodies from pigs that were experimentally infected with PRRSV. In addition, Mab2-5G2 identified a soluble protein on MA-104 and porcine alveolar macrophages. These results indicate that Mab2-5G2 may be a useful candidate as an alternative PRRSV serodiagnostic reagent and a useful probe to study PRRSV-cell interaction.