The Role of Latency-Associated Transcripts in the Latent Infection of Pseudorabies Virus.

Pseudorabies virus (PRV) can cause neurological, respiratory, and reproductive diseases in pigs and establish lifelong latent infection in the peripheral nervous system (PNS). Latent infection is a typical feature of PRV, which brings great difficulties to the prevention, control, and eradication of pseudorabies. The integral mechanism of latent infection is still unclear. Latency-associated transcripts (LAT) gene is the only transcriptional region during latent infection of PRV which plays the key role in regulating viral latent infection and inhibiting apoptosis. Here, we review the characteristics of PRV latent infection and the transcriptional characteristics of the LAT gene. We also analyzed the function of non-coding RNA (ncRNA) produced by the LAT gene and its importance in latent infection. Furthermore, we provided possible strategies to solve the problem of latent infection of virulent PRV strains in the host. In short, the detailed mechanism of PRV latent infection needs to be further studied and elucidated.

Supplementation of H7N9 Virus-Like Particle Vaccine With Recombinant Epitope Antigen Confers Full Protection Against Antigenically Divergent H7N9 Virus in Chickens.

The continuous evolution of the H7N9 avian influenza virus suggests a potential outbreak of an H7N9 pandemic. Therefore, to prevent a potential epidemic of the H7N9 influenza virus, it is necessary to develop an effective crossprotective influenza vaccine. In this study, we developed H7N9 virus-like particles (VLPs) containing HA, NA, and M1 proteins derived from H7N9/16876 virus and a helper antigen HMN based on influenza conserved epitopes using a baculovirus expression vector system (BEVS). The results showed that the influenza VLP vaccine induced a strong HI antibody response and provided effective protection comparable with the effects of commercial inactivated H7N9 vaccines against homologous H7N9 virus challenge in chickens. Meanwhile, the H7N9 VLP vaccine induced robust crossreactive HI and neutralizing antibody titers against antigenically divergent H7N9 viruses isolated in wave 5 and conferred on chickens complete clinical protection against heterologous H7N9 virus challenge, significantly inhibiting virus shedding in chickens. Importantly, supplemented vaccination with HMN antigen can enhance Th1 immune responses; virus shedding was completely abolished in the vaccinated chickens. Our study also demonstrated that viral receptor-binding avidity should be taken into consideration in evaluating an H7N9 candidate vaccine. These studies suggested that supplementing influenza VLP vaccine with recombinant epitope antigen will be a promising strategy for the development of broad-spectrum influenza vaccines.

The effectiveness of traditional Chinese medicine fumigation and washing nursing care after arthroscopic debridement of Knee Osteoarthritis: A protocol for systematic review and meta-analysis.

BACKGROUND: Knee Osteoarthritis (KOA) is a degenerative osteoarthrosis with knee joint pain as the main symptom. In recent years, arthroscopic removal of loose body and repair of meniscus have become common methods for the treatment of KOA. However, postoperative pain, swelling and limited joint movement affect the functional recovery of knee joint and the effect of surgical treatment. Early postoperative control of pain and swelling is of great significance to improve the curative effect of arthroscopic debridement and promote the recovery of knee joint function. In recent years, many clinical studies have reported that the nursing method of fumigation and washing with Chinese medicine after arthroscopic debridement of KOA can relieve pain, promote the recovery of joint function and improve the clinical curative effect, but there is a lack of evidence-based medicine. The purpose of this study is to evaluate the efficacy and safety of fumigation and washing with traditional Chinese medicine after KOA arthroscopy. METHODS: Computer retrieval English database (PubMed, Embase, Web of Science, the Cochrane Library) and Chinese database (China National Knowledge Infrastructure, Wanfang, VIP Database for Chinese Technical Periodicals, China Biology Medicine disc), moreover manual retrieval academic, Google and baidu from building to since December 2020, traditional Chinese medicine fumigation applied to KOA arthroscopy postoperative nursing of randomized controlled clinical research, by two researchers independently evaluated the quality of the included study and extracted the data. Meta-analysis of the included literatures was performed using RevMan5.3 software. RESULTS: The main observation index of this study was the effective rate, and the secondary indexes included Visual Analogue Scale Score, the Western Ontario and McMaster university orthopedic index, Lysholms score and adverse reactions, so as to evaluate the efficacy and safety of traditional Chinese medicine fumigation nursing after KOA arthroscopy. CONCLUSION: This study will provide reliable evidence for the clinical application of Fumigation and washing nursing of traditional Chinese medicine after KOA arthroscopy. ETHICS AND DISSEMINATION: Private information from individuals will not be published. This systematic review also does not involve endangering participant rights. Ethical approval will not be required. The results may be published in a peer-reviewed journal or disseminated at relevant conferences. OSF REGISTRATION NUMBER: DOI 10.17605/OSF.IO/THZP4.

Better immune efficacy triggered by the inactivated gI/gE-deleted pseudorabies virus with the additional insertion of gC gene in mice and weaned pigs.

A new variant of pseudorabies virus (PRV) with high pathogenicity has been prevalent in many swineherds vaccinated with Bartha-K61 in China since 2011. Several gene-deleted vaccine candidates have been developed based on new emerging PRV variants. PRV-AH, a new emerging PRV strain from Anhui Province, was isolated in our laboratory in 2013. In the present study, rPRV-AH-gI-/gE- and rPRV-AH-gI-/gE-/gC+ were generated based on PRV-AH by homologous recombination. The growth kinetics of rPRV-AH-gI-/gE- and rPRV-AH-gI-/gE-/gC+ were similar to their parental strains. Compared with the commercial inactivated vaccine of Ea strain, the immune efficacy of the inactivated vaccine based on recombinant viruses was evaluated in mice and weaned pigs. The result showed that the level of neutralizing antibody in mice immunized with rPRV-AH-gI-/gE-/gC+ was higher compared with those immunized with rPRV-AH-gI-/gE- at a dose of 106 TCID50 at 8 weeks post initial immunization (p < 0.0001). Among the groups immunized at a dose of 105 TCID50, the rPRV-AH-gI-/gE- group showed a survival rate of 37.5 %, while the rPRV-AH-gI-/gE-/gC+ group showed a protection rate of 87.5 % against the PRV-AH challenge. Besides, the rPRV-AH-gI-/gE- and rPRV-AH-gI-/gE-/gC+ group immunized at a dose of 106 TCID50 showed a survival rate of 100 %. Interestingly, compared with the commercial vaccine group, the group of 105 TCID50 rPRV-AH-gI-/gE-/gC+ showed a lower level of neutralizing antibodies (p < 0.0001) but the same protection rate in mice. Moreover, in the pig experiment, the level of neutralizing antibodies in the group vaccinated with inactivated rPRV-AH-gI-/gE-/gC+ was higher than any other groups at 8 weeks post initial immunization (p < 0.05). More importantly, the milder symptoms and pathological lesions occurred in pigs vaccinated with rPRV-AH-gI-/gE-/gC+ after challenge with 106 TCID50 PRV-AH, revealing that additional insertion of gC gene could enhance the protective efficacy in PRV gI/gE-deleted vaccine in pigs. Collectively, these above-mentioned findings suggested that the inactivated vaccine of rPRV-AH-gI-/gE-/gC+ had a better immune efficacy, which could be regarded as a promising inactivated vaccine candidate for PRV control.

The Network of Interactions Between Classical Swine Fever Virus Nonstructural Protein p7 and Host Proteins.

Classical swine fever (CSF) is a highly contagious viral disease causing severe economic losses to the swine industry. As viroporins of viruses modulate the cellular ion balance and then take over the cellular machinery, blocking the activity of viroporin or developing viroporin-defective attenuated vaccines offers new approaches to treat or prevent viral infection. Non-structural protein p7 of CSF virus (CSFV) is a viroporin, which was highly involved in CSFV virulence. Deciphering the interaction between p7 and host proteins will aid our understanding of the mechanism of p7-cellular protein interaction affecting CSFV replication. In the present study, seven host cellular proteins including microtubule-associated protein RP/EB family member 1 (MAPRE1), voltage-dependent anion channel 1 (VDAC1), proteasome maturation protein (POMP), protein inhibitor of activated STAT 1 (PIAS1), gametogenetin binding protein 2 (GGNBP2), COP9 signalosome subunit 2 (COPS2), and contactin 1 (CNTN1) were identified as the potential interactive cellular proteins of CSFV p7 by using yeast two-hybrid (Y2H) screening. Plus, the interaction of CSFV p7 with MAPRE1 and VDAC1 was further evaluated by co-immunoprecipitation and GST-pulldown assay. Besides, the p7-cellular protein interaction network was constructed based on these seven host cellular proteins and the STRING database. Enrichment analysis of GO and KEGG indicated that many host proteins in the p7-cellular protein interaction network were mainly related to the ubiquitin-proteasome system, cGMP-PKG signaling pathway, calcium signaling pathway, and JAK-STAT pathway. Overall, this study identified potential interactive cellular proteins of CSFV p7, constructed the p7-cellular protein interaction network, and predicted the potential pathways involved in the interaction between CSFV p7 and host cells.

Overcoming Hypoxia-Restrained Radiotherapy Using an Erythrocyte-Inspired and Glucose-Activatable Platform.

Radiotherapy (RT) as one of the most powerful cancer treatment strategies has been greatly restricted by tumor hypoxia. A mounting effort has been devoted to develop oxygen delivery systems for boosting the RT effect. Unluckily, those systems only supplied modest oxygen, which could not afford more than once and long-time RT. Herein, we describe the development of a glucose-regulated drug release platform, allowing for a long-term tumor normoxic microenvironment and repeated RT for a long time. The repeated cycles resulted in sustained high Endostar plasma levels, which dramatically normalized the tumor vasculature and chronically reversed tumor hypoxia. Taking advantage of the inexhaustible supply of oxygen, Endo@GOx-ER enabled RT achieved an impressive cancer treatment output. To the best of our knowledge, our strategy is the initial attempt to overcome tumor-hypoxia-limited RT through the normalization of tumor vasculature by using an erythrocyte-inspired and glucose-activatable platform and it visually casts a light on the clinical development.

Genome-Wide Transcriptional Profiling Reveals Two Distinct Outcomes in Central Nervous System Infections of Rabies Virus.

Rabies remains a major public health concern in many developing countries. The precise neuropathogenesis of rabies is unknown, though it is hypothesized to be due to neuronal death or dysfunction. Mice that received intranasal inoculation of an attenuated rabies virus (RABV) strain HEP-Flury exhibited subtle clinical signs, and eventually recovered, which is different from the fatal encephalitis caused by the virulent RABV strain CVS-11. To understand the neuropathogenesis of rabies and the mechanisms of viral clearance, we applied RNA sequencing (RNA-Seq) to compare the brain transcriptomes of normal mice vs. HEP-Flury or CVS-11 intranasally inoculated mice. Our results revealed that both RABV strains altered positively and negatively the expression levels of many host genes, including genes associated with innate and adaptive immunity, inflammation and cell death. It is found that HEP-Flury infection can activate the innate immunity earlier through the RIG-I/MDA-5 signaling, and the innate immunity pre-activated by HEP-Flury or Newcastle disease virus (NDV) infection can effectively prevent the CVS-11 to invade central nervous system (CNS), but fails to clear the CVS-11 after its entry into the CNS. In addition, following CVS-11 infection, genes implicated in cell adhesion, blood vessel morphogenesis and coagulation were mainly up-regulated, while the genes involved in synaptic transmission and ion transport were significantly down-regulated. On the other hand, several genes involved in the MHC class II-mediated antigen presentation pathway were activated to a greater extent after the HEP-Flury infection as compared with the CVS-11 infection suggesting that the collaboration of CD4(+) T cells and MHC class II-mediated antigen presentation is critical for the clearance of attenuated RABV from the CNS. The differentially regulated genes reported here are likely to include potential therapeutic targets for expanding the post-exposure treatment window for RABV infection.

[Effects of Two Placement Ways for Storage of Blood Bag on Biochemical Indexes of Leukodepleted Red Blood Cells].

OBJECTIVE: To investigate the effects of 2 different ways of storage bag placement on some biochemical indexes of leukodepleted red blood cells (LD-RBC) to as to ensure the efficacy and safety of clinical blood transfusion. METHODS: The whole blood samples of 20 donors (400 ml/donor) were selected for preparating the LP-RBC, which were divided evenly into 10 bags. The 10 bags were randomly divided into 2 groups; the bags in 1 group were placed uprightly, while the bags in another group were placed horizontally. The bags of 2 groups were stored in the same conditions. One storage bag from each group was taken randomly on day 7, 14, 21, 28, 35 respectively, and then the biochemical indexes of samples were detected and analyzed. RESULTS: The values of K(+) and LAC on day 14, the value of LDH on day 28 in the uprightly placed group were higher than those in the horizontally placed group (P < 0.05), the value of Na(+) on day 28, and the value of Glu on day 35 in the uprightly placed group were lower than those in horizontally placed group (P < 0.05), but there was no significant difference in Cl(-) level between 2 groups (P > 0.05). CONCLUSION: The storage bags placed by different ways during the storage show different influence on some biochemical indexes of LD-RBC in the storage period.

Production of monoclonal antibody against EP0 protein of pseudorabies virus and determination of its recognized epitope.

Early protein 0 (EP0) is especially important for modulating PRV gene expression and reactivation from the latent state, but the mechanisms have not been elucidated. In this study, six monoclonal antibodies (MAbs) against EP0 protein of PRV were generated and their characterizations were investigated. Western blot analysis showed all six MAbs could react with immunizing antigen, but only 2B12 and 2C6 could react with native EP0 protein from PRV-infected cells. ELISA additivity tests revealed that at least three epitopes in EP0 were defined by six MAbs. The epitope recognized by MAb 2B12 was further identified in 287-292 aa of EP0 protein using a series of expressed overlapping peptides. These MAbs may provide valuable tools for further research of the functions of EP0 in PRV infection.

Classical swine fever virus triggers RIG-I and MDA5-dependent signaling pathway to IRF-3 and NF-κB activation to promote secretion of interferon and inflammatory cytokines in porcine alveolar macrophages.

BACKGROUND: Classical swine fever (CSF) caused by CSF virus (CSFV) is a highly contagious disease of pigs. The RNA helicases retinoic acid-inducible gene I (RIG-I) and melanoma differentiation-associated gene 5 (MDA-5) are differentially involved in the detection of various RNA viruses. In present study, we investigated the roles of RIG-I and MDA-5 in eliciting antiviral and inflammatory responses to CSFV shimen strain in Porcine alveolar macrophages (PAMs). METHODS: CSFV Shimen strain was used as challenge virus in this study and PAMs were cultured in vitro. Interferon regulatory factor (IRF)-3 and nuclear factor-kappa B (NF-κB) translocation was detected using immunofluorescent staining; RIG-I, MDA5, interferon promoter-stimulating factor 1 (IPS-1), IRF-3 and NF-κB expression was measured by Western Blotting; Interferon beta (IFN-ß), IFN-α, interleukin-1beta (IL-1ß), IL-6 and tumor necrosis factor (TNF-α) expression was tested by Enzyme-linked immunosorbent assays (ELISA) and shRNA-mediated knockdown of MDA5 or RIG-I was performed. RESULTS: The findings suggested that the initial response to CSFV infection resulted in the higher expression of RIG-I and MDA5 leading to the activation of IPS-1, IRF-3 and NF-κB in a dose-dependent manner. Evaluation of IFN-α, IFN-ß, IL-1ß, IL-6 or TNF-α expressed by PAMs showed significant differences between infected and uninfected cells. CSFV infected cells induced to express high levels of IFN-α, IFN-ß, IL-1ß, IL-6 and TNF-α in a dose-dependent way within 24 h post-infection (hpi). At the same time, CSFV improved the nuclear translocation of IRF-3 and NF-κB. We also directly compared and assessed the roles of RIG-I and MDA5 in triggering innate immune actions during CSFV infection through shRNA-mediated knockdown of MDA5 or RIG-I. We found that, compared to the control, the production of IFN-α, IFN-ß, IL-1ß, IL-6 and TNF-α in response to CSFV infection was heavily reduced in RIG-I knockdown cells while it was moderately decreased in MDA5 knockdown cells. PAMs derived from knockdown of both RIG-I and MDA5 almost failed to produce IFNs and inflammatory cytokines. CONCLUSIONS: It indicates that CSFV can be recognized by both RIG-I and MDA5 to initiate the RIG-I signaling pathway to trigger innate defenses against infection.

Genome and molecular characterization of a CSFV strain isolated from a CSF outbreak in South China.

In the present study, the full-length nucleotide sequences of the CSFV-GZ-2009 strain of classical swine fever virus (CSFV) isolated from a hog pen in Guangdong province in China was determined. Results demonstrated that the genome of CSFV-GZ-2009 is 12,298 nucleotides (nt) in length, is composed of a 373-nt 5'-untranslated region (UTR), has an 11,697-nt open reading frame encoding a polyprotein of 3,898 amino acids, and has a 228-nt 3'-UTR. Genome comparison of the CSFV-GZ-2009 isolate (GenBank accession No. HQ380231) with other CSFV strains was also analyzed. Gene regions from CSFV-GZ-2009 and other known strains were shown to share 92.7-96.7% identity at the nucleotide level and 94.7-99.2% identity at the amino acid level. Phylogenetic analysis of the full-length genome and the following regions E(rns), E2 and NS5B revealed that the CSFV-GZ-2009 isolate was classified within subgroup 1.1 of group I and closely related to the highly virulent strain JL1 (06), cF114, Shimen and SWH with pairwise distances of 0.0037, 0.0043, 0.0058 and 0.0107, respectively. Analysis of recombination with the SimPlot program demonstrated that strain CSFV-GZ-2009 was not a naturally homologous recombinant. Furthermore, the change of clinical signs of pigs after infection of CSFV-GZ-2009 isolates showed typical symptoms such as diarrhea, persistent fever, and mononuclear lymphocytopenia after CSFV infection. Based on phylogenetic analysis and an animal infection test, we could conclude that the CSFV-GZ-2009 isolate belonged to subgroup 1.1 of group I and was of high virulence.

Genome sequence of canine parvovirus strain SC02/2011, isolated from a puppy with severe diarrhea in south China.

A widespread hemorrhagic gastroenteritis in young dogs occurred in South China. A virulent field canine parvovirus (CPV) strain, SC02/2011, was isolated from a puppy showing enteric signs in Guangdong, China. The genome of CPV strain SC02/2011 was sequenced and analyzed, which will promote a better understanding of the molecular epidemiology and genetic diversity of CPV field isolates in South China.

Classical swine fever virus failed to activate nuclear factor-kappa b signaling pathway both in vitro and in vivo.

BACKGROUND: Classical swine fever virus (CSFV) is the cause of CSF which is a severe disease of pigs, leading to heavy economic losses in many regions of the world. Nuclear factor-kappa B (NF-κB) is a critical regulator of innate and adaptive immunity, and commonly activated upon viral infection. In our previous study, we found that CSFV could suppress the maturation and modulate the functions of monocyte-derived dendritic cells (Mo-DCs) without activating NF-κB pathway. To further prove the effects of CSFV on the NF-κB signaling pathway, we investigated the activity of NF-κB after CSFV infection in vivo and in vitro. METHODS: Attenuated Thiverval strain and virulent wild-type GXW-07 strain were used as challenge viruses in this study. Porcine kidney 15 (PK-15) cells were cultured in vitro and peripheral blood mononuclear cells (PBMCs) were isolated from the blood of CSFV-infected pigs. DNA binding of NF-κB was measured by electrophoretic mobility shift assays (EMSA), NF-κB p65 translocation was detected using immunofluorescent staining, and p65/RelA and IκBα expression was measured by Western Blotting. RESULTS: Infection of cells with CSFV in vitro and in vivo showed that compared with tumor necrosis factor alpha (TNF-α) stimulated cells, there was no distinct DNA binding band of NF-κB, and no significant translocation of p65/RelA from the cytoplasm to the nucleus was observed, which might have been due to the apparent lack of IkBa degradation. CONCLUSIONS: CSFV infection had no effect on the NF-κB signaling pathway, indicating that CSFV could evade host activation of NF-κB during infection.

Classical swine fever virus suppresses maturation and modulates functions of monocyte-derived dendritic cells without activating nuclear factor kappa B.

Classical swine fever virus (CSFV) compromises the host immune system, causing the severe disease of pigs. Dendritic cells (DCs) are the most potent inducers of immune responses. In the present study, we investigated the functional properties of porcine monocyte-derived DCs (Mo-DCs) affected by CSFV. Results showed that the expression of surface markers of DCs such as major histocompatibility complex class II (MHC-II), CD80, CD83 and CD86 were unimpaired, but an obviously increased expression of CD172a in DCs was noticed 48 h after CSFV infection. The expression profiles of cytokines were detected in cultured Mo-DCs after various treatments for 48 h by Q-RT-PCR. The findings suggested that CSFV infection significantly increased the mRNA expression of IL-10 and TNF-α, and inhibited IL-12 expression, with little effect on IFN-α and IFN-γ expression. We further demonstrated that CSFV was incapable of activating the nuclear factor kappa B (NF-κB) in infected DCs, which was characterized by an unvaried DNA binding activity of NF-κB, the lack of translocation of p65/RelA from the cytoplasm to the nucleus and the stabilization of p65/RelA expression. Furthermore, Western blot analysis indicated that the inactivation of NF-κB was due to the failure of IκBα degradation. The data demonstrated that CSFV could be replicated in DCs and CSFV infection could modulate the secretion of crucial co-stimulatory molecules and cytokines which down-regulated maturation of DCs, without activating NF-κB in DCs. Thus, the results suggested a possible mechanism for CSFV evasion of innate host defenses, providing the basis for understanding molecular pathways in CSFV pathogenesis.

Genetic diversity and positive selection analysis of classical swine fever virus isolates in south China.

Classical swine fever virus (CSFV) causes a highly contagious disease that leads to significant economic losses in the pig industry worldwide. However, there is a paucity of knowledge on the accurate genotyping of CSFV isolates in south China. This study genotyped the E2 gene of 14 CSFV strains isolated during 2008-2010 from domestic pigs in different districts of south China. Phylogenetic analyses revealed that all of the 14 CSFV isolates were clustered into genetic subgroup 1.1. This contrasts with most parts of China, where group 2 isolates are predominant. Furthermore, the positive selection pressures acting on the E(rns) and E2 envelope protein genes of CSFV were assessed and a site-by-site analysis of the dN/dS ratio was performed to identify specific codons that undergo diversification under positive selection. While no significant evidence for positive selection was observed in E(rns), two positively selected sites at amino acid residues 49 and 72 in the E2 encoding region were identified. Our results revealed that a predominance of subgroup 1.1 CSFV isolates is currently circulating in some districts of south China, which appear to be unrelated to the Chinese C-strain vaccine. Moreover, the envelope protein gene, E2, has undergone positive selection in 14 CSFV strains and two positively selected sites have been identified in this study. Understanding the molecular epidemiology and functional importance of these positively selected amino acid positions could help to predict possible changes in virulence, the development of vaccines and disease control.

Development of a direct competitive enzyme-linked immunosorbent assay using a sensitive monoclonal antibody for bisphenol A.

To set up an immunoassay-based method to detect Bisphenol A (BPA), we generated a monoclonal antibody (MAb) using a specially designed carboxyl derivative of BPA as the immunogen. BPA-HS was synthesized by reaction using BPA and succinic anhydride. The mice were immunized with the BPA-HS-BSA conjugate. The MAb was obtained from a hybridoma. In addition, we showed that the MAb was highly specific for BPA. The limit of detection was approximately 0.05 ng mL(-1) (ppb) in assay buffer and 0.1 ng mL(-1) (ppb) in water samples. The recoveries of BPA for water samples were from 90.8% to 114%, and coefficients of variation were from 15.6% to 39.4%. Thus, the ELISA method is a rapid and high throughput screening tool to detect BPA in water products.

Use of visual loop-mediated isotheral amplification of rimM sequence for rapid detection of Mycobacterium tuberculosis and Mycobacterium bovis.

Mycobacterium tuberculosis and Mycobacterium bovis are pathogenic bacterial species in the genus Mycobacterium and the causative agents of most cases of tuberculosis (TB). Detection of M. tuberculosis and M. bovis using conventional culture- and biochemical-based assays is time-consuming and laborious. Therefore, a simple and sensitive method for rapid detection has been anxiously awaited. In the present study, a visual loop-mediated isothermal amplification (LAMP) assay was designed from the rimM (encoding 16S rRNA-processing protein) gene sequence and used to rapidly detect M. tuberculosis and M. bovis from clinical samples in South China. The visual LAMP reaction was performed by adding calcein and manganous ion, allowing the results to be read by simple visual observation of color change in a closed-tube system, and which takes less than 1 h at 65 degrees C. The assay correctly identified 84 M. tuberculosis isolates, 3 M. bovis strains and 1 M. bovis BCG samples, but did not detect 51 non-tuberculous mycobacteria (NTM) isolates and 8 other bacterial species. Sensitivity of this assay for detection of genomic DNA was 1 pg. Specific amplification was confirmed by the ladder-like pattern of gel electrophoresis and restriction enzyme HhaI digestion. The assay successfully detected M. tuberculosis and M. bovis not only in pure bacterial culture but also in clinical samples of sputum, pleural fluid and blood. The speed, specificity, sensitivity of the rimM LAMP, the lack of a need for expensive equipment, and the visual readout show great potential for clinical detection of M. tuberculosis and M. bovis.

Enzyme-linked immunosorbent assay (ELISA) using a specific monoclonal antibody as a new tool to detect Sudan dyes and Para red.

To set up an immunoassay-based method to detect Sudan dyes and Para red, we generated a monoclonal antibody (Mab) using a specially designed carboxyl derivative of Sudan I (CSD I) as the immunogen. CSD I was synthesized by azocoupling reaction using 2-naphthol and diazotised 4-aminobenzoic acid. The antibody was obtained from a hybridoma, which was derived from the fusion of the mouse myeloma SP2/0 cells and the splenocytes from the mice immunized with the CSD I-bovine serum albumin (BSA) conjugate. In addition, we showed that the Mab was highly specific for Sudan I, III and Para red. The limit of detection was approximately 0.01ngmL(-1) in phosphate-buffered saline (PBS) buffer and 0.5ngg(-1) in chilli tomato sauce. The recoveries of Sudan I, III and Para red for the chilli tomato sauce were from 84% to 99% and coefficients of variation were from 14.9% to 33.3%. Thus, the enzyme-linked immunosorbent assay (ELISA) method is a rapid and high throughput screening tool to detect Sudan dyes and Para red in food products.

[Recombination and expression of ORF1 and ORF2 gene of porcine circovirus type 2 and gene of pseudorabies virus].

ORF1 and ORF2 gene of porcine circovirus type 2 were cloned by PCR with the specific primers designed according to genome of PCV2 (AY035820). Following extraction and digestion, PCR products were subsequently inserted into universal transfer vector plECMV (deleted partial gE and gI of pseudorabies virus) to generate recombinant transfer plasmid pIEORF1-ORF2. The genomic DNA of PRV TK-/gE- /LacZ+ strain and pIEORF1-ORF2 were co-transfected into IBRS-2 cells with lipofectin, and recombinant virus TK- /gE- /gI- /ORF1-ORF2+ was selected by PCR with ORF1 gene and ORF2 gene primers respectively. The recombinant virus was analyzed with Southern blotting and Western blotting. The results indicated that ORF1 and ORF2 gene of PCV2 had been inserted into the genome of TK- /gE- /LacZ+ strain and the expressed ORF1-ORF2 fusion protein could react with PCV2 positive sera. Result of virus titers detection showed the insertion of ORF1 and ORF2 gene did not influence propagation of recombinant virus.

Immunogenicity of a recombinant pseudorabies virus expressing ORF1-ORF2 fusion protein of porcine circovirus type 2.

Porcine circovirus type 2 (PCV2) is associated with post-weaning multisystemic wasting syndrome (PMWS). Pseudorabies (PR) is also an important infectious disease in swine and sometimes co-infect with PCV2. An attenuated pseudorabies virus (PRV) has been successfully used as a vector for live viral vaccines. In this study, a recombinant PRV expressing ORF1-ORF2 fusion protein of PCV2 was constructed and its immunogenicity was tested in mice and pigs. The ORF1 and partial ORF2 gene of PCV2 Yu-A strain were amplified by PCR and inserted into a transfer vector. The recombinant transfer plasmid was co-transfected with the EcoRI digested genome of vector virus (PRV TK-/gE-/LacZ+) into IBRS-2 cells. The recombinant pseudorabies virus PRV-PCV2 was purified by plaque purification and identified by PCR and Southern blotting. Expression of the ORF1-ORF2 fusion protein by the recombinant PRV-PCV2 virus was demonstrated by Western blotting analysis. The growth properties of the recombinant virus in cells were similar to that of the parent vector virus. In animal experiments, PRV-PCV2 elicited strong anti-PRV and anti-PCV2 antibodies in Balb/c mice as indicated by PRV-neutralizing assay, anti-PCV2 ELISA and PCV2 specific lymphocyte proliferation assay, respectively. And PRV-PCV2 immunization protected mice against a lethal challenge of a virulent PRV Ea strain. In pigs, PRV-PCV2 elicited significant immune response towards PRV and PCV2 as indicated by PRV-ELISA, PRV neutralizing assay and PCV2 specific lymphocyte proliferation assay, respectively. This is a first step toward the development of a potential candidate divalent vaccine against PRV and PCV2 infections.