Biopanning of polypeptides binding to bovine ephemeral fever virus G1 protein from phage display peptide library

Prevalence characteristic of BVDV in some large scale dairy farms in Western China

The aim of this study was to analyze the prevalence characteristic of Bovine viral diarrhea virus (BVDV) in some large scale dairy farms in Western China. BVDV was detected in 30 samples of bulk tank milk (BTM) collected from 30 large dairy farms in 7 provinces of western China, 93.33% (28/30) of the farms were infected with BVDV, and S/P ratio was over 0.3 in 28 positive farms. The individual status was further estimated in the dairy farm (No. 10) with the highest positive rate (S/P ratio = 1.37) and the dairy farm (No. 17) with the lowest positive rate (S/P ratio = 0.39). Two hundred cows were, respectively, selected from calf, young cows and lactating cows in farm No. 10 and farm No. 17 and the serum sample of each enrolled cow was collected. The individual positive rate of serum antibody (Ab) was 87.17% (523/600) in farm No. 10 and 31.33% (188/600) in farm No. 17. The individual positive ratio of serum antibody in calves, young cows and lactating cows were 41.75 % (167/400), 58.75% (235/400) and 77.25% (309/400), respectively. BTM Ab of farm No. 10 has an S/P ratio more than 1.0, which indicated there were emergent or persistent infection (PI) cases, and further test showed that PI cases were 0.51% in farm No. 10. Pathogens were positive in 42.34% (163/385) of nasal mucus samples collected from cows with respiratory symptom, and BVDV cases were 57 in 163 positive samples. Three strains of NCP BVDV-1, one strain of CP BVDV-1, one strain of NCP BVDV-2 and one strain of CP BVDV-2 were successfully isolated. Phylogenetic analysis revealed that the subtypes of BVDV currently prevalent in western China were BVDV-1a, BVDV-1m, BVDV-1q and BVDV-2. The findings suggested that the BVDV infection is serious in some Large Scale Dairy Farms in Western China.

Mimotope-Based Immunoassays for the Rapid Analysis of Mycotoxin: A Review

Mycotoxins are toxic contaminants in foods and feeds that are naturally occurring and largely unavoidable. Determining their contents in these products is essential to protect humans from harm. Immunoassays of mycotoxins have been well-established because they are fast, sensitive, simple, and cost-effective. However, a major limitation of immunoassays is the requirement of toxic mycotoxins as competing antigens, standards, or competing tracers. Mimotopes are peptides or proteins that can specifically bind to antibodies and compete with analytes for binding sites by mimicking antigenic epitopes. They can be employed as substitutes for competing antigens, standards, or competing tracers to avoid use of mycotoxins. This review summarizes the production and functionalization of the two main kinds of mimotopes, mimic peptides and anti-idiotypic antibodies (Ab2), and their applications in rapid analysis of mycotoxins.

A novel copper (II) binding peptide for a colorimetric biosensor system design

Filamentous bacteriophages are viruses infecting only bacteria. In this study, phage display technique was applied to identify highly selective Cu(II) binding peptides. After five rounds of positive screening against Cu(II) and various rounds of negative screenings against competitive metal ions (Al(III), Co(II), Fe(III), Ni(II) and Zn(II)), bacteriophages were enriched. Selective Cu(II) binding of final phages was confirmed by Enzyme Linked Immunosorbent Assay (ELISA), Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray spectroscopy (EDX) analyses. 15 phage plaques were randomly selected and sequenced. Cu-5 peptide (HGFANVA) with the highest frequency of occurrence and the strongest Cu(II) affinity was chosen for further Cu(II) detection and removal tests. Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) confirmed the strong Cu(II) binding potential of engineered viruses. Cu-5 peptides were synthetically synthesized with three Cysteine units at C-terminal and a AuNP-peptide biosensor system was developed based on aggregation behavior of AuNPs upon Cu(II) ion treatment. AuNP-based Cu(II) sensor was selective for Cu(II) and the LOD was 91.15 nM (ca. 5.8 × 10^-3 mg/L; 3σ/k, n = 5, R² = 0.992) for the case study which is considerably lower than the WHO's accepted guideline of 1.3 mg/L. This study provides an interdisciplinary approach to apply short peptides as recognition units for biosensor studies which are user friendly, not bulky and cost-effective.

Discovery of Antivirals Using Phage Display

The latest coronavirus disease outbreak, COVID-19, has brought attention to viral infections which have posed serious health threats to humankind throughout history. The rapid global spread of COVID-19 is attributed to the increased human mobility of today's world, yet the threat of viral infections to global public health is expected to increase continuously in part due to increasing human-animal interface. Development of antiviral agents is crucial to combat both existing and novel viral infections. Recently, there is a growing interest in peptide/protein-based drug molecules. Antibodies are becoming especially predominant in the drug market. Indeed, in a remarkably short period, four antibody therapeutics were authorized for emergency use in COVID-19 treatment in the US, Russia, and India as of November 2020. Phage display has been one of the most widely used screening methods for peptide/antibody drug discovery. Several phage display-derived biologics are already in the market, and the expiration of intellectual property rights of phage-display antibody discovery platforms suggests an increment in antibody drugs in the near future. This review summarizes the most common phage display libraries used in antiviral discovery, highlights the approaches employed to enhance the antiviral potency of selected peptides/antibody fragments, and finally provides a discussion about the present status of the developed antivirals in clinic.

RACK1 degrades MAVS to promote bovine ephemeral fever virus replication via upregulating E3 ubiquitin ligase STUB1

Receptors for activated C kinase 1 (RACK1) could competitively combine with mitochondrial antiviral signaling protein (MAVS) to inhibit the type I interferon (IFN) signaling pathway during viral infection in vitro. However, whether RACK1 can degrade MAVS to enhance viral replication is still unknown. In this study, we found that bovine epidemic fever virus (BEFV) infection triggered the expression of RACK1. Overexpression of RACK1 promoted BEFV replication, while knockdown of RACK1 inhibited the replication of BEFV. Further research showed that RACK1 inhibited the type I IFN signaling pathway during BEFV infection by degrading MAVS, and RACK1 degraded MAVS via the ubiquitin-proteasome system. Mechanistically, RACK1 up-regulated the expression of E3 ubiquitin ligase STIP1 homology and U-box containing protein 1 (STUB1), thereby promoting the ubiquitination and degradation of MAVS. In addition, RACK1 degraded MAVS by enhancing the interaction between STUB1 and MAVS but not via its interaction with STUB1. Overall, our study reveals a novel mechanism by which RACK1 inhibits the type I IFN signaling pathway to BEFV infection through degradation of MAVS, thereby promoting viral infection. These findings provide a new perspective for the MAVS degradation regulated by RACK1.

Mini review: immunologic functions of dual oxidases in mucosal systems of vertebrates

Abstract Mucosal epithelial cells act as the first immunologic barrier of organisms, and contact directly with pathogens. Therefore, hosts must have differential strategies to combat pathogens efficiently. Reactive oxygen species (ROS), as a kind of oxidizing agents, participates in the early stage of killing pathogens quickly. Recent reports have revealed that dual oxidase (DUOX) plays a key role in mucosal immunity. And the DUOX is a transmembrane protein which produces ROS as their primary enzymatic products. This process is an important pattern for eliminating pathogens. In this review, we highlight the DUOX immunologic functions in the respiratory and digestive tract of vertebrates.

Food-Derived Opioid Peptides in Human Health: A Review

World Health Organization data suggest that stress, depression, and anxiety have a noticeable prevalence and are becoming some of the most common causes of disability in the Western world. Stress-related disorders are considered to be a challenge for the healthcare system with their great economic and social impact. The knowledge on these conditions is not very clear among many people, as a high proportion of patients do not respond to the currently available medications for targeting the monoaminergic system. In addition, the use of clinical drugs is also associated with various side effects such as vomiting, dizziness, sedation, nausea, constipation, and many more, which prevents their effective use. Therefore, opioid peptides derived from food sources are becoming one of the safe and natural alternatives because of their production from natural sources such as animals and plant proteins. The requirement for screening and considering dietary proteins as a source of bioactive peptides is highlighted to understand their potential roles in stress-related disorders as a part of a diet or as a drug complementing therapeutic prescription. In this review, we discussed current knowledge on opioid endogenous and exogenous peptides concentrating on their production, purification, and related studies. To fully understand their potential in stress-related conditions, either as a drug or as a therapeutic part of a diet prescription, the need to screen more dietary proteins as a source of novel opioid peptides is emphasized.

Annexin A2 gene interacting with viral matrix protein to promote bovine ephemeral fever virus release

Bovine ephemeral fever virus (BEFV) causes bovine ephemeral fever, which can produce considerable economic damage to the cattle industry. However, there is limited experimental evidence regarding the underlying mechanisms of BEFV. Annexin A2 (AnxA2) is a calcium and lipid-conjugated protein that binds phospholipids and the cytoskeleton in a Ca²⁺-dependent manner, and it participates in various cellular functions, including vesicular trafficking, organization of membrane domains, and virus proliferation. The role of the AnxA2 gene during virus infection has not yet been reported. In this study, we observed that AnxA2 gene expression was up-regulated in BHK-21 cells infected with the virus. Additionally, overexpression of the AnxA2 gene promoted the release of mature virus particles, whereas BEFV replication was remarkably inhibited after reducing AnxA2 gene expression by using the small interfering RNA (siRNA). For viral proteins, overexpression of the Matrix (M) gene promotes the release of mature virus particles. Moreover, the AnxA2 protein interaction with the M protein of BEFV was confirmed by GST pull-down and co-immunoprecipitation assays. Experimental results indicate that the C-terminal domain (268-334 aa) of AxnA2 contributes to this interaction. An additional mechanistic study showed that AnxA2 protein interacts with M protein and mediates the localization of the M protein at the plasma membrane. Furthermore, the absence of the AnxA2-V domain could attenuate the effect of AnxA2 on BEFV replication. These findings can contribute to elucidating the regulation of BEFV replication and may have implications for antiviral strategy development.

Genetically modified rabies virus vector-based bovine ephemeral fever virus vaccine induces protective immune responses against BEFV and RABV in mice

Bovine ephemeral fever (BEF), caused by the bovine ephemeral fever virus (BEFV), is associated with an acute febrile infection in cattle and widespread in tropical and subtropical areas, leading to great economic losses to cattle and milk industry. However, no efficacious BEF vaccine is currently available in China. Herein, we generated a recombinant rabies virus (RABV) expressing BEFV glycoprotein (LBNSE-BG), utilizing a reverse genetics system based on the recombinant rabies virus strain LBNSE. It was found that mice immunized with LBNSE-BG produced robust neutralizing antibodies against both BEFV and RABV, and developed complete protection from lethal RABV challenge. Further studies showed that LBNSE-BG activated more dendritic cells (DCs), B cells and T cells in immunized mice than the parent virus LBNSE. Collectively, these findings demonstrate that the recombinant LBNSE-BG described here has the potential to be developed as a cost-effective and efficacious bivalent vaccine for cattle use in endemic areas of BEF and rabies.

Induction of the Unfolded Protein Response during Bovine Alphaherpesvirus 1 Infection

Bovine herpesvirus 1 (BoHV-1) is an alphaherpesvirus that causes great economic losses in the cattle industry. Herpesvirus infection generally induces endoplasmic reticulum (ER) stress, and the unfolded protein response (UPR) in infected cells. However, it is not clear whether ER stress and UPR can be induced by BoHV-1 infection. Here, we found that ER stress induced by BoHV-1 infection could activate all three UPR sensors (the activating transcription factor 6 (ATF6), the inositol-requiring enzyme 1 (IRE1), and the protein kinase RNA-like ER kinase (PERK)) in MDBK cells. During BoHV-1 infection, the ATF6 pathway of UPR did not affect viral replication. However, both knockdown and specific chemical inhibition of PERK attenuated the BoHV-1 proliferation, and chemical inhibition of PERK significantly reduced the viral replication at the post-entry step of the BoHV-1 life cycle. Furthermore, knockdown of IRE1 inhibits BoHV-1 replication, indicating that the IRE1 pathway may promote viral replication. Further study revealed that BoHV-1 replication was enhanced by IRE1 RNase activity inhibition at the stage of virus post-entry in MDBK cells. Furthermore, IRE1 kinase activity inhibition and RNase activity enhancement decrease BoHV1 replication via affecting the virus post-entry step. Our study revealed that BoHV-1 infection activated all three UPR signaling pathways in MDBK cells, and BoHV-1-induced PERK and IRE1 pathways may promote viral replication. This study provides a new perspective for the interactions of BoHV-1 and UPR, which is helpful to further elucidate the mechanism of BoHV-1 pathogenesis.

Antiviral Peptides: Identification and Validation

Despite rapid advances in the human healthcare, the infection caused by certain viruses results in high morbidity and mortality accentuate the importance for development of new antivirals. The existing antiviral drugs are limited, due to their inadequate response, increased rate of resistance and several adverse side effects. Therefore, one of the newly emerging field “peptide-based therapeutics” against viruses is being explored and seems promising. Over the last few years, a lot of scientific effort has been made for the identification of novel and potential peptide-based therapeutics using various advanced technologies. Consequently, there are more than 60 approved peptide drugs available for sale in the market of United States, Europe, Japan, and some Asian countries. Moreover, the number of peptide drugs undergoing the clinical trials is rising gradually year by year. The peptide-based antiviral therapeutics have been approved for the Human immunodeficiency virus (HIV), Influenza virus and Hepatitis virus (B and C). This review enlightens the various peptide sources and the different approaches that have contributed to the search of potential antiviral peptides. These include computational approaches, natural and biological sources (library based high throughput screening) for the identification of lead peptide molecules against their target. Further the applications of few advanced techniques based on combinatorial chemistry and molecular biology have been illustrated to measure the binding parameters such as affinity and kinetics of the screened interacting partners. The employment of these advanced techniques can contribute to investigate antiviral peptide therapeutics for emerging infections.

Detection of bovine viral diarrhea virus genotype 1 in aerosol by a real time RT-PCR assay

BACKGROUND

As a pestivirus of the Flaviviridae family, bovine viral diarrhea virus (BVDV), has imposed a large burden on animal husbandry worldwide, and such virus can be transmitted mainly through direct contact with other infected animals and probably via aerosols. In the present study, we aimed to develop a real-time RT-PCR method for detection of BVDV-1 in aerosol samples.

METHODS

A pair of primers specific for highly conserved regions of the BVDV-1 5'-UTR was designed. The standard curve and sensitivity of the developed assay were assessed based on 10-fold serial dilutions of RNA molecular standard. The specificity of the assay was evaluated with other pestiviruses and infectious bovine viruses. The clinical performance was examined by testing 169 aerosol samples.

RESULTS

The results showed that a good linear relationship existed between the standard curve and the concentration of template. The lowest detection limit was 5.2 RNA molecules per reaction. This assay was specific for detection of BVDV-1, and no amplification was found for other pestiviruses such as classical swine fever virus (CSFV), border disease virus (BDV), and common infectious bovine viruses, including BVDV-2, infectious bovine rhinotracheitis virus (IBRV), bovine parainfluenza virus type 3 (BPIV-3), bovine respiratory syncytial virus (BRSV), bovine ephemeral fever virus (BEFV) and bovine coronavirus (BcoV). The assay was highly reproducible with low variation coefficient values (CVs) for intra-assay and inter-assay. A total of 169 aerosol samples collected from six dairy herds were tested using this method. The results showed that the positive detection rate of BVDV-1 was 17.2% (29/169), which was significantly higher compared with the conventional RT-PCR. Additionally, the positive samples (n = 29) detected by real-time RT-PCR were verified by BVDV RPA-LFD, and a concordance rate of 100% was obtained between them.

CONCLUSIONS

Taken together, we developed a real-time RT-PCR assay for quantitative analysis of BVDV-1 in aerosol samples, and our finding provided valuable insights into the risk on aerosol transmission of BVDV-1.

Beta-catenin inhibits bovine parainfluenza virus type 3 replication via innate immunity pathway

Background

Bovine parainfluenza virus type 3 (BPIV3) is one of the important viral respiratory agents associated with the bovine respiratory disease complex (BRDC) in cattle. Previous study has demonstrated that infection of BPIV3 causes innate immune response within the host cell. β-catenin is a key component of the Wnt/β-catenin signal pathway which is involved in the regulation of interferon-beta (IFN-β) transcription. Some viruses can activate while others can inhibit the Wnt/β-catenin signaling pathway. However, the role of β-catenin in BPIV3 infection remains unclear.

Results

Here we found that the expression of β-catenin mRNA was up-regulated and β-catenin protein was down-regulated after BPIV3 infection in MDBK cells. Moreover, it was confirmed that overexpression of β-catenin suppressed BPIV3 replication and knockdown of β-catenin promoted viral replication, suggesting that β-catenin inhibits BPIV3 replication. Furthermore, IFN-β signal pathway and virus titer analysis using the GSK3β inhibitor (LiCl) revealed that Wnt/β-catenin can serve as a mechanism to suppress virus replication in infected cells. The results indicated that LiCl promoted the expression and accumulation in the nucleus of β-catenin, which further promoted the expression of IFN-β and OSA1 and suppressed BPIV3 replication. Most importantly, BPIV3 down-regulating β-catenin protein expression was due to degradation of GSK3β mediated proteasome pathway.

Conclusions

In summary, we discovered the relationship between β-catenin and BPIV3 replication. These results provided further insight into the study of BPIV3 pathogenesis.

Alteration of cell junctions during viral infection

Cell junctions serve as a protective barrier for cells and provide an important channel for information transmission between cells and the surrounding environment. Viruses are parasites that invade and commandeer components of host cells in order to survive and replicate, and they have evolved various mechanisms to alter cell junctions to facilitate viral infection. In this review, we examined the current state of knowledge on the action of viruses on host cell junctions. The existing evidence suggests that targeting the molecules involved in the virus-cell junction interaction can prevent the spread of viral diseases.

Cell Cycle Regulation in the Plant Response to Stress

As sessile organisms, plants face a variety of environmental challenges. Their reproduction and survival depend on their ability to adapt to these stressors, which include water, heat stress, high salinity, and pathogen infection. Failure to adapt to these stressors results in programmed cell death and decreased viability, as well as reduced productivity in the case of crop plants. The growth and development of plants are maintained by meiosis and mitosis as well as endoreduplication, during which DNA replicates without cytokinesis, leading to polyploidy. As in other eukaryotes, the cell cycle in plants consists of four stages (G1, S, G2, and M) with two major check points, namely, the G1/S check point and G2/M check point, that ensure normal cell division. Progression through these checkpoints involves the activity of cyclin-dependent kinases and their regulatory subunits known as cyclins. In order for plants to survive, cell cycle control must be balanced with adaption to dynamic environmental conditions. In this review, we summarize recent advances in our understanding of cell cycle regulation in plants, with a focus on the molecular interactions of cell cycle machinery in the context of stress tolerance.

Monomer-targeting affinity peptide inhibitors of amyloid with no self-fibrillation and low cytotoxicity

A monomer-targeting strategy based on solution-phase biopanning to obtain peptide inhibitors increases the suppression efficiency and reduces the cytotoxicity of amylin.

Antiviral activity of phage display-selected peptides against Japanese encephalitis virus infection in vitro and in vivo

Japanese Encephalitis virus (JEV) is a zoonotic flavivirus that is the most significant etiological agent of childhood viral neurological infections. However, no specific antiviral drug is currently available to treat JEV infections. The JEV envelope (E) protein is a class II viral fusion protein that mediates host cell entry, making interference with the interaction between the E protein of JEV and its cognate receptors an attractive strategy for anti-JEV drug development. In this study, we identified a peptide derived from a phage display peptide library against the E protein of JEV, designated P1, that potentially inhibits in vitro and in vivo JEV infections. P1 inhibits JEV infection in BHK-21 cells with 50% inhibitory capacity at a concentration of 35.9 μM. The time-of-addition assay indicates that JEV replication is significantly inhibited during pre-infection and co-infection of P1 with JEV while post-infection treatments with P1 have very little impact on JEV proliferation, showing that P1 inhibits JEV infection at early stages and indicating the potential prophylactic effect of P1. We adapted an in vitro BiFC assay system and demonstrated that P1 interacts with JEV E proteins and blocks their entry into cells. We also evaluated the therapeutic efficacy of P1 in a lethal JEV mouse model exhibiting systemic and brain infections. Interestingly, P1 treatment protected C57BL/6 mice against mortality, markedly reduced the viral loads in blood and brain, and diminished the histopathological lesions in the brain cells. In addition to controlling systemic infection, P1 has a very low level of cytotoxicity and acts in a sequence-specific manner, as scrambled peptide sP1 does not show any antiviral activity. In conclusion, our in vitro and in vivo experimental findings show that P1 possesses antiviral activity against JEV infections, is safe to use, and has potential for further development as an antiviral treatment against JEV infections.

Assembly of pigeon circovirus-like particles using baculovirus expression system

Pigeon circovirus (PiCV) is able to infect racing and meat pigeons of all ages and is a key factor that triggers young pigeon disease syndrome (YPDS). PiCV vaccine research has been impeded because PiCV cannot be grown or propagated in cell cultures. Virus-like particles (VLPs), which can be generated by a wide range of expression systems, have been shown to have outstanding immunogenicity and constitute promising vaccines against a wide range of pathogens. Cap protein, which contains neutralizing antibody epitopes, is the only capsid protein of PiCV. In this study, the baculovirus expression system was utilized to express the PiCV Cap protein, which was self-assembled into VLPs with a spherical morphology and diameters of 15-18 nm. Specific antibodies against the Cap protein were induced after BALB/c mice immunized intramuscularly (i.m.) with VLPs combined with adjuvant. Based on these findings, PiCV VLPs may be a promising candidate vaccine against PiCV.

A novel reassortant influenza A (H1N1) virus infection in swine in Shandong Province, eastern China

Influenza A (H1N1) viruses are distributed worldwide and pose a threat to public health. Swine, as a natural host and mixing vessel of influenza A (H1N1) virus, play a critical role in the transmission of this virus to humans. Furthermore, swine influenza A (H1N1) viruses have provided all eight genes or some genes to the genomes of influenza strains that historically have caused human pandemics. Hence, persistent surveillance of influenza A (H1N1) virus in swine herds could contribute to the prevention and control of this virus. Here, we report a novel reassortant influenza A (H1N1) virus generated by reassortment between 2009 pandemic H1N1 viruses and swine viruses. We also found that this virus is prevalent in swine herds in Shandong Province, eastern China. Our findings suggest that surveillance of the emergence of the novel reassortant influenza A (H1N1) virus in swine is imperative.

Chemosensory Gene Families in the Oligophagous Pear Pest Cacopsylla chinensis (Hemiptera: Psyllidae)

Chemosensory systems play an important role in insect behavior, and some key associated genes have potential as novel targets for pest control. Cacopsylla chinensis is an oligophagous pest and has become one of the main pests of pear trees, but little is known about the molecular-level means by which it locates its hosts. In this study, we assembled the head transcriptome of C. chinensis using Illumina sequencing, and 63,052 Unigenes were identified. A total of 36 candidate chemosensory genes were identified, including five different families: 12 odorant binding proteins (OBPs), 11 chemosensory proteins (CSPs), 7 odorant receptors (ORs), 4 ionotropic receptors (IRs), and 2 gustatory receptors (GRs). The number of chemosensory gene families is consistent with that found in other Hemipteran species, indicating that our approach successfully obtained the chemosensory genes of C. chinensis. The tissue expression of all genes using quantitative real-time PCR (qRT-PCR) found that some genes displayed male head, female head, or nymph-biased specific/expression. Our results enrich the gene inventory of C. chinensis and provide valuable resources for the analysis of the functions of some key genes. This will help in developing molecular targets for disrupting feeding behavior in C. chinensis.

Two mutations in viral protein enhance the adaptation of waterfowl-origin H3N2 virus in murine model

After serial passage of a waterfowl-origin H3N2 subtype avian influenza virus in BALB/c mice, we obtained H3N2 mouse-adapted variants and identified eight amino acid substitutions in five viral proteins in our previous study. Here, we analyze the key mutations determining viral pathogenicity in mammals. We found that both PB2-D701N mutation and M1-M192V mutation were implicated in the viral pathogenic phenotypic variation of H3N2 avian influenza virus in mice. Furthermore, we found that PB2-D701N could enhance viral replication in vitro and in vivo and expanded viral tissue tropism. Our data suggest that PB2-D701N and M1-M192V are the virulence markers of H3N2 avian influenza virus, and these markers can be used in the trans-species transmission surveillance for the H3N2 avian influenza virus.

PB2 and hemagglutinin mutations confer a virulent phenotype on an H1N2 avian influenza virus in mice

We previously obtained mouse-adapted variants of H1N2 avian influenza virus that contained PB2-L134H, PB2-I647L, PB2-D701N, HA-G228S, and M1-D231N mutations. Here, we analyzed the effects of these mutations on viral pathogenicity in a mammalian model. By evaluating the virulence of mouse-adapted H1N2 variants at different generations, we found that the PB2-D701N and HA-G228S mutations both contribute to the virulence of this virus in mammals. Furthermore, we found that the PB2-D701N and HA-G228S mutations both enhance the ability of the virus to replicate in vivo and in vitro and that the PB2-D701N substitution results in an expansion of viral tissue tropism. These results suggest that the PB2-D701N mutation and the HA-G228S mutation are the major mammalian determinants of H1N2 virus. These results help us to understand more about the mechanisms by which influenza viruses adapt to mammals, and monitoring of these mutations can be used in continuous influenza surveillance to assess the pandemic potential of avian influenza virus variants.

Use of a recombinase polymerase amplification commercial kit for rapid visual detection of Pasteurella multocida

Background

Pasteurella multocida (P. multocida) is a bacterium that causes bovine respiratory disease (BRD) and haemorrhagic septicaemia (HS) in cattle, buffaloes and bison. Rapid point-of-care diagnosis or regular testing of Pasteurellosis, therefore, could contribute greatly to early detection, and screening infected animal is important. Up to now, there are no published reports on the use of recombinase polymerase amplification (RPA) combined with a lateral flow dipstick (LFD) for P. multocida detection.

Results

This study proposes a promising isothermal detection method for P. multocida with the potential to be developed as an on-site test for Pasteurellosis. The method includes an RPA combined with LFD. First, the analytical sensitivity and specificity of P. multocida RPA-LFD were tested. The RPA-LFD, performed at 39 °C, successfully detected P. multocida DNA in 30 min, with a detection limit of up to 120 copies per reaction. Then, the practicability of RPA-LFD was analysed using 62 nasal swabs and 33 fresh lungs samples from 17 different dairy farms. Compared to real-time quantitative PCR (qPCR), the RPA-LFD assay yielded a clinical specificity of 95.15%, positive predictive value (PPV) of 95.15% and 0.958 kappa coefficient. Compared with the culture method, it achieved 100% sensitivity, 67.20% specificity and a 0.572 kappa coefficient.

Conclusions

These results combined with the simple conditions required for the performance of the RPA-LFD assay, have demonstrated the effectiveness and practicability of the method for development into a regular on-site protocol for the diagnosis of Pasteurellosis.

Cellular microRNA bta-miR-2361 inhibits bovine herpesvirus 1 replication by directly targeting EGR1 gene

Bovine herpesvirus 1 (BHV-1) is an economically important pathogen of cattle and has led to significant consequences on the cattle industry worldwide. MicroRNAs (miRNAs) are a class of regulators that play critical roles in virus and host interaction. However, the roles of host miRNAs in BHV-1 infection remain largely unclear. In this study, a set of differentially expressed miRNAs by small RNA deep sequencing were analyzed in the Madin-Darby Bovine Kidney Cells (MDBK) infected with BHV-1 after 12 h, 24 h and 48 h post-infection compared to mock infection, and it was confirmed that bta-miR-2361 was significantly down-regulated. Moreover, bta-miR-2361 mimics transfection could inhibit BHV-1 replication. Combined with up-regulated genes from BHV-1-infected MDBK cells by deep RNA-sequencing and predicted by bioinformatics tools, early growth response 1 (EGR1) was putative target of bta-miR-2361. Furthermore, EGR1 was up-regulated during BHV-1 infection, and overexpression of EGR1 promoted BHV-1 replication whereas knockdown of EGR1 had the opposite effects. Subsequently, the target association between bta-miR-2361 and 3'UTR of EGR1 was further validated using a dual-luciferase reporter assay. In addition, overexpression of bta-miR-2361 resulted in decreased EGR1 mRNA and protein levels. Further mechanistic study showed that EGR1 stimulated BHV-1 UL46 promoter activity, but overexpression of bta-miR-2361 suppressed the production of UL46 gene. Collectively, this is the first study to reveal that bta-miR-2361 as a novel host factor regulates BHV-1 replication via directly targeting the EGR1 gene, which is a transcription factor that regulates viral UL46 gene of BHV-1. These results provide further insight into the study of BHV-1 pathogenesis.

Electrochemical Biosensors for Detection of Foodborne Pathogens

Foodborne safety has become a global public health problem in both developed and developing countries. The rapid and precise monitoring and detection of foodborne pathogens has generated a strong interest by researchers in order to control and prevent human foodborne infections. Traditional methods for the detection of foodborne pathogens are often time-consuming, laborious, expensive, and unable to satisfy the demands of rapid food testing. Owing to the advantages of simplicity, real-time analysis, high sensitivity, miniaturization, rapid detection time, and low cost, electrochemical biosensing technology is more and more widely used in determination of foodborne pathogens. Here, we summarize recent developments in electrochemical biosensing technologies used to detect common foodborne pathogens. Additionally, we discuss research challenges and future prospects for this field of study.

Phylostratigraphic analysis of gene co-expression network reveals the evolution of functional modules for ovarian cancer

Ovarian cancer (OV) is an extremely lethal disease. However, the evolutionary machineries of OV are still largely unknown. Here, we used a method that combines phylostratigraphy information with gene co-expression networks to extensively study the evolutionary compositions of OV. The present co-expression network construction yielded 18,549 nodes and 114,985 edges based on 307 OV expression samples obtained from the Genome Data Analysis Centers database. A total of 20 modules were identified as OV related clusters. The human genome sequences were divided into 19 phylostrata (PS), the majority (67.45%) of OV genes was already present in the eukaryotic ancestor. There were two strong peaks of the emergence of OV genes screened by hypergeometric test: the evolution of the multicellular metazoan organisms (PS5 and PS6, P value = 0.002) and the emergence of bony fish (PS11 and PS12, P value = 0.009). Hence, the origin of OV is far earlier than its emergence. The integrated analysis of the topology of OV modules and the phylogenetic data revealed an evolutionary pattern of OV in human, namely, OV modules have arisen step by step during the evolution of the respective lineages. New genes have evolved and become locked into a pathway, where more and more biological pathways are fixed into OV modules by recruiting new genes during human evolution.

Targeted inhibition of histone deacetylase 6 in inflammatory diseases

Targeting epigenetic modification of gene expression represents a promising new approach under investigation for the treatment of inflammatory diseases. Accumulating evidence suggests that epigenetic mechanisms, such as histone modification, play a crucial role in a number of inflammatory diseases, including rheumatoid arthritis, asthma, and contact hypersensitivity. Consistent with this role, histone deacetylase (HDAC) inhibitors have shown efficacy in the treatment of inflammatory diseases. In particular, selective inhibitors of HDAC6, a cytoplasmic member of the HDAC family that contains two deacetylase domains, are under investigation as a potential treatment strategy for inflammatory diseases due to their ability to regulate inflammatory cells and cytokines. Here, we review recent findings highlighting the critical roles of HDAC6 in a variety of inflammatory diseases, and discuss the therapeutic potential of HDAC6 inhibitors in these settings.

Genetic characterization of an H13N2 low pathogenic avian influenza virus isolated from gulls in China

Low pathogenic avian influenza viruses circulate in wild birds but are occasionally transmitted to other species, including poultry, mammals and humans. To date, infections with low pathogenic avian influenza viruses of HA subtype 6, HA subtype 7, HA subtype 9 and HA subtype 10 among humans have been reported. However, the epidemiology, genetics and ecology of low pathogenic avian influenza viruses have not been fully understood thus far. Therefore, persistent surveillance of low pathogenic avian influenza virus infections in wild birds and other species is needed. Here, we found a low pathogenic avian influenza virus of the subtype H13N2 (abbreviated as WH42) in black-tailed gulls in China. All gene sequences of this H13N2 virus were determined and used for subsequent analysis. Phylogenetic analysis of the HA gene and NA gene indicated that WH42 was derived from the Eurasian lineage. We analysed the timing of the reassortment events and found that WH42 was a reassortant whose genes were transferred from avian influenza viruses circulating in Asia, Europe and North America. Additionally, WH42 possessed several molecular markers associated with mammalian virulence and mammalian transmissibility. Interestingly, we also found low but detectable haemagglutination inhibition antibodies against H13N2 low pathogenic avian influenza virus in serum samples collected from chickens. Taken together, our findings show that the H13 virus may have been introduced into poultry and that sustainable surveillance in gulls and poultry is required.

MiR-3470b promotes bovine ephemeral fever virus replication via directly targeting mitochondrial antiviral signaling protein (MAVS) in baby hamster Syrian kidney cells

BACKGROUND

Bovine ephemeral fever virus (BEFV), the causative agent of bovine ephemeral fever, is an economically important pathogen of cattle and water buffalo. MicroRNAs (miRNAs) are endogenous 21-23 nt small non-coding RNA molecules that binding to a multiple of target mRNAs and functioning in the regulation of viral replication including the miRNA-mediated antiviral defense. However, the reciprocal interaction between bovine ephemeral fever virus replication and host miRNAs still remain poorly understood. The aim of our study herein was to investigate the exact function of miR-3470b and its molecular mechanisms during BEFV infection.

RESULTS

In this study, we found a set of microRNAs induced by BEFV infection using small RNA deep sequencing, and further identified BEFV infection could significantly up-regulate the miR-3470b expression in Baby Hamster Syrian Kidney cells (BHK-21) after 24 h and 48 h post-infection (pi) compared to normal BHK-21 cells without BEFV infection. Additionally, the target association between miR-3470b and mitochondrial antiviral signaling protein (MAVS) was predicted by target gene prediction tools and further validated using a dual-luciferase reporter assay, and the expression of MAVS mRNA and protein levels was negatively associated with miR-3470b levels. Furthermore, the miR-3470b mimic transfection significantly contributed to increase the BEFV N mRNA, G protein level and viral titer, respectively, whereas the miR-3470b inhibitor had the opposite effect on BEFV replication. Moreover, the overexpression of MAVS or silencing of miR-3470b by its inhibitors suppressed BEFV replication, and knockdown of MAVS by small interfering RNA also promoted the replication of BEFV.

CONCLUSIONS

Our findings is the first to reveal that miR-3470b as a novel host factor regulates BEFV replication via directly targeting the MAVS gene in BHK-21 cells and may provide a potential strategy for developing effective antiviral therapy.

Development of a recombinase polymerase amplification combined with a lateral flow dipstick assay for rapid detection of the Mycoplasma bovis

BACKGROUND

Mycoplasma bovis (M. bovis) is a major etiological agent of bovine mycoplasmosis around the world. Point-of-care testing in the field is lacking owing to the requirement for a simple, robust field applicable test that does not require professional laboratory equipment. The recombinase polymerase amplification (RPA) technique has become a promising isothermal DNA amplify assay for use in rapid and low-resource diagnostics.

RESULTS

Here, a method for specific detection of M. bovis DNA was established, which was RPA combined with lateral flow dipstick (LFD). First, the analytical specificity and sensitivity of the RPA primer and LF-probe sets were evaluated. The assay successfully detected M. bovis DNA in 30 min at 39 °C, with detection limit of 20 copies per reaction, which it was compared the real-time quantitative PCR (qPCR) assay. This method was specific because it did not detect a selection of other bacterial pathogens in cattle. Both qPCR and RPA-LFD assays were used to detect M. bovis 442 field samples from 42 different dairy farms in Shandong Province of China, also the established RPA-LFD assay obtained 99.00% sensitivity, 95.61% specificity, and 0.902 kappa coefficient compared with the qPCR.

CONCLUSIONS

To the author's knowledge, this is the first report using an RPA-FLD assay to visualise and detect M. bovis. Comparative analysis with qPCR indicates the potential of this assay for rapid diagnosis of bovine mycoplasmosis in resource limited settings.

Development and evaluation of serotype-specific recombinase polymerase amplification combined with lateral flow dipstick assays for the diagnosis of foot-and-mouth disease virus serotype A, O and Asia1

Background

Foot-and-mouth disease (FMD) caused by foot-and-mouth disease virus (FMDV) is one of the most highly infectious diseases in livestock, and leads to huge economic losses. Early diagnosis and rapid differentiation of FMDV serotype is therefore integral to the prevention and control of FMD. In this study, a series of serotype-specific reverse transcription recombinase polymerase amplification assays combined with lateral flow dipstick (RPA-LFD) were establish to differentiate FMDV serotypes A, O or Asia 1, respectively.

Results

The serotype-specific primers and probes of RPA-LFD were designed to target conserved regions of the FMDV VP1 gene sequence, and three primer and probe sets of serotype-specific RPA-LFD were selected for amplification of FMDV serotypes A, O or Asia 1, respectively. Following incubation at 38 °C for 20 min, the RPA amplification products could be visualized by LFD. Analytical sensitivity of the RPA assay was then determined with ten-fold serial dilutions of RNA of VP1 gene and the recombinant vector respectively containing VP1 gene from FMDV serotypes A, O or Asia1, the detection limits of these assays were 3 copies of plasmid DNA or 50 copies of viral RNA per reaction. Moreover, the specificity of the assay was assessed, and there was no cross reactions with other viruses leading to bovine vesicular lesions. Furthermore, 126 clinical samples were respectively detected with RPA-LFD and real-time PCR (rPCR), there was 98.41% concordance between the two assays, and two samples were positive by RPA-LFD but negative in rPCR, these were confirmed as FMDV-positive through viral isolation in BHK-21 cells. It showed that RPA-LFD assay was more sensitive than the rPCR method in this study.

Conclusion

The development of serotype-specific RPA-LFD assay provides a rapid, sensitive, and specific method for differentiation of FMDV serotype A, O or Asia1, respectively. It is possible that the serotype-specific RPA-LFD assay may be used as a integral protocol for field detection of FMDV.

Prevalence of bovine viral diarrhea virus in dairy cattle herds in eastern China

Bovine viral diarrhea virus (BVDV) is a worldwide spreading pestivirus affecting cattle and other ruminants; however, there have been few reports on epidemiologic investigation of BVDV in eastern China. In this study, bulk tank milk from 36 herds of dairy cattle in eastern China was submitted to serological investigations, 77.8% of herds was BVDV antibody positive. Individual animal status in two herds was further investigated collecting blood samples, the positive ratio was 49.74% and 24.64%, and the average positive ratio of calves, heifers, and lactating cows was 15.94%, 40.16%, and 41.7%, respectively. Moreover, clinical survey was carried out among 8170 dairy cattle from 36 herds, for diarrhea syndrome, respiratory problems and reproductive failure, and pathogens of all clinical cattle were further investigated. The results showed that BVDV was one of the main pathogen, which infected animals combining with various other viruses. Then, nine BVDV strains were isolated; phylogenetic analysis showed that BVDV subtypes currently circulating in eastern China were BVDV 1a and BVDV 1c. In addition, out of 377 cows tested, the 1.86% detected positive to the BVDV antigen. This study provided the foundation of further study on vaccination and control strategies of BVDV in eastern China.

Isolation and genetic characterization of H13N8 low pathogenic avian influenza virus from migratory birds in eastern China

Low pathogenic avian influenza virus (LPAIV) is an important zoonotic pathogen. Migratory birds are the natural reservoir for all 16 haemagglutinin (HA) and nine neuraminidase (NA) subtypes of LPAIV. Surveillance of LPAIV in migratory waterfowl and poultry is important for animal and public health. An understanding of the ecology and epidemiology of LPAI viruses in their reservoirs is beneficial for routine surveillance projects. Here, we report the isolation of an H13N8 LPAIV from black-tailed gulls in eastern China. Full genome sequences of this isolate were determined. Genetic analysis of the HA and NA segments of this isolate showed that this H13N8 LPAIV was derived from the Eurasian lineage. Additionally, we speculate that this H13N8 LPAIV was a reassortant between the North American and Eurasian lineages. Interestingly, we identified amino acid motifs responsible for increased virulence or transmission of influenza viruses in mammals. We also found weak but measurable haemagglutination inhibition antibody titers against H13N8 virus in serum samples collected from chickens. These results suggest that continued surveillance for LPAI viruses in migratory birds and poultry is required.

Applications of SERS in the Detection of Stress-Related Substances

A wide variety of biotic and abiotic stresses continually attack plants and animals, which adversely affect their growth, development, reproduction, and yield realization. To survive under stress conditions, highly sophisticated and efficient tolerance mechanisms have been evolved to adapt to stresses, which consist of the variation of effector molecules playing vital roles in physiological regulation. The development of a sensitive, facile, and rapid analytical methods for stress factors and effector molecules detection is significant for gaining deeper insight into the tolerance mechanisms. As a nondestructive analysis technique, surface-enhanced Raman spectroscopy (SERS) has unique advantages regarding its biosensing applications. It not only provides specific fingerprint spectra of the target molecules, conformation, and structure, but also has universal capacity for simultaneous detection and imaging of targets owing to the narrow width of the Raman vibrational bands. Herein, recent progress on biotic and abiotic stresses, tolerance mechanisms and effector molecules is summarized. Moreover, the development and promising future trends of SERS detection for stress-related substances combined with nanomaterials as substrates and SERS tags are discussed. This comprehensive and critical review might shed light on a new perspective for SERS applications.

Analysis of Biomolecules Based on the Surface Enhanced Raman Spectroscopy

Analyzing biomolecules is essential for disease diagnostics, food safety inspection, environmental monitoring and pharmaceutical development. Surface-enhanced Raman spectroscopy (SERS) is a powerful tool for detecting biomolecules due to its high sensitivity, rapidness and specificity in identifying molecular structures. This review focuses on the SERS analysis of biomolecules originated from humans, animals, plants and microorganisms, combined with nanomaterials as SERS substrates and nanotags. Recent advances in SERS detection of target molecules were summarized with different detection strategies including label-free and label-mediated types. This comprehensive and critical summary of SERS analysis of biomolecules might help researchers from different scientific backgrounds spark new ideas and proposals.

A lateral flow dipstick combined with reverse transcription recombinase polymerase amplification for rapid and visual detection of the bovine respirovirus 3

Bovine respirovirus 3 also known as Bovine parainfluenza virus type 3 (BPIV3) is one of the most important viral respiratory agents of both young and adult cattle. Rapid diagnosis could contribute greatly in containing epidemics and thus avoid economic losses. However, the lack of robust isothermal visual method poses difficulty. In this study, a novel isothermal assay for detecting BPIV3 was established. The method includes a lateral flow dipstick (LFD) assay combined with reverse transcription recombinase polymerase amplification (RT-RPA). First, the analytical sensitivity and specificity of BPIV3 LFD RT-RPA were tested. The LFD RT-RPA assay has a detection limit of up to 100 copies per reaction in 30 min at 38 °C. Then the performance of LFD RT-RPA was evaluated using 95 clinical samples. Compared to qPCR, the LFD RT-RPA assay showed a clinical sensitivity of 94.74%, a clinical specificity of 96.05% and 0.8734 kappa coefficient. These results have demonstrated the efficiency and effectiveness of the method to be developed into a point of care protocol for the diagnosis of BPIV3.

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A LFD RT-RPA assay for detection of BPIV3 was developed.

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The RPA-nfo primer and probe sets were highly specific to BPIV3.

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Primer and probe sets were highly sensitive, detecting up to 100 copies per reaction.

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Compared to qPCR, the LFD RT-RPA assay showed a clinical sensitivity of 94.74% and a clinical specificity of 96.05%.

Rapid visual detection of Mycobacterium avium subsp. paratuberculosis by recombinase polymerase amplification combined with a lateral flow dipstick

Paratuberculosis (Johne's disease) is a chronic debilitating disease of domestic and wild ruminants. However, widespread point-of-care testing is infrequent due to the lack of a robust method. The isothermal recombinase polymerase amplification (RPA) technique has applied for rapid diagnosis. Herein, RPA combined with a lateral flow dipstick (LFD) assay was developed to estimate DNA from Mycobacterium avium subsp. paratuberculosis. First, analytical specificity and sensitivity of the RPA-nfo primer and probe sets were assessed. The assay successfully detected M. paratuberculosis DNA in 30 min at 39℃ with a detection limit of up to eight copies per reaction, which was equivalent to that of the real-time quantitative polymerase chain reaction (qPCR) assay. The assay was specific, as it did not amplify genomes from five other Mycobacterium spp. or five pathogenic enteric bacteria. Six hundred-twelve clinical samples (320 fecal and 292 serum) were assessed by RPA-LFD, qPCR, and enzyme-linked immunosorbent assay, respectively. The RPA-LFD assay yielded 100% sensitivity, 97.63% specificity, and 98.44% concordance rate with the qPCR results. This is the first report utilizing an RPA-LFD assay to visualize and rapidly detect M. paratuberculosis. Our results show this assay should be a useful method for the diagnosis of paratuberculosis in resource-constrained settings.

Rapid detection of foot-and-mouth disease virus using reverse transcription recombinase polymerase amplification combined with a lateral flow dipstick

Foot-and-mouth disease caused by foot-and-mouth disease virus (FMDV) is one of the most highly contagious diseases of domestic animals, and leads to enormous economic loss. Currently there are two main prevention and control strategies for the disease: eradication of the infected animals in FMDV free countries, and vaccination of the susceptible animals in countries with endemic FMDV infection. Early discovery and diagnosis of the source of infection is therefore integral to the containment of FMDV. In this study, a two-step reverse transcription recombinase polymerase amplification assay combined with lateral flow detection (RPA-LFD) was developed to detect FMDV. With incubation at 38 °C, a region of the 2B gene on the FMDV genome was successfully amplified within 20 min using specific primers and a probe. The amplified RPA product can be visualized on a lateral flow dipstick. The RPA-LFD assay was highly sensitive, detecting down to 10 copies of plasmid DNA. There was no cross-reactivity with other pathogens causing vesicular lesions. In addition, 143 clinical samples were used to compare RPA-LFD with real-time PCR, with 98.6% concordance between the assays. Therefore, the developed RPA-LFD assay provides a rapid, simple, highly promising approach to be used as point-of-care diagnostics in the field.