DDX5 inhibits inflammation by modulating m6A levels of TLR2/4 transcripts during bacterial infection.

DExD/H-box helicases are crucial regulators of RNA metabolism and antiviral innate immune responses; however, their role in bacteria-induced inflammation remains unclear. Here, we report that DDX5 interacts with METTL3 and METTL14 to form an m6A writing complex, which adds N6-methyladenosine to transcripts of toll-like receptor (TLR) 2 and TLR4, promoting their decay via YTHDF2-mediated RNA degradation, resulting in reduced expression of TLR2/4. Upon bacterial infection, DDX5 is recruited to Hrd1 at the endoplasmic reticulum in an MyD88-dependent manner and is degraded by the ubiquitin-proteasome pathway. This process disrupts the DDX5 m6A writing complex and halts m6A modification as well as degradation of TLR2/4 mRNAs, thereby promoting the expression of TLR2 and TLR4 and downstream NF-κB activation. The role of DDX5 in regulating inflammation is also validated in vivo, as DDX5- and METTL3-KO mice exhibit enhanced expression of inflammatory cytokines. Our findings show that DDX5 acts as a molecular switch to regulate inflammation during bacterial infection and shed light on mechanisms of quiescent inflammation during homeostasis.

[Quantification of antigen of Mycoplasma capricolum subsp. capripneumoniae by optical assay].

Mycoplasma capricolum subsp. capripneumoniae (Mccp) is the cause of contagious caprine pleuropneumonia (CCPP) in goats. Inactivated vaccines and capsular polysaccharide (CPS) indirect hemagglutination reagents are available for prevention and serological detection, but high culture costs and complex antigen quantification have been plagued by production staff. In order to solve these problems in production practice, a sugar fermentation medium with an initial pH value of 7.8, which could improve the production of two antigens simultaneously, was screened out by changing the initial pH value based on previous Mccp metabolomics analysis. Since phenol red can be identified by UV absorption spectrum and cetyltrimethylammonium bromide (CTAB) can bind to anionic capsular polysaccharide, a UV spectrum measurement method for analyzing the culture stage reached by Mccp and a CTAB precipitation test for relative quantification of capsular polysaccharide antigen content in the fermentation broth were established. The UV spectrum observation method can guide the production of Mccp according to the growth curve of Mccp, which greatly reduces the monitoring time of the traditional CCU method and improves the accuracy of the original eye-observation method. The established CTAB precipitation test can complete the monitoring of CPS content within 5 hours, which greatly reduces the time required compared with the traditional differential technique, and its accuracy was verified by the phenol-sulfuric acid method. The optimized culture medium and the two correlation comparison methods established in this study can effectively reduce the production cost of Mccp and improve the production efficiency. The two assays have been used in the research at our laboratory, which provides experimental data for further improvement of the production process of CCPP inactivated vaccine and capsular polysaccharide as well as rapid quantification.

Functional Characterization of a Novel SMR-Type Efflux Pump RanQ, Mediating Quaternary Ammonium Compound Resistance in Riemerella anatipestifer.

Riemerella anatipestifer (R. anatipestifer) is a multidrug-resistant bacterium and an important pathogen responsible for major economic losses in the duck industry. Our previous study revealed that the efflux pump is an important resistance mechanism of R. anatipestifer. Bioinformatics analysis indicated that the GE296_RS02355 gene (denoted here as RanQ), a putative small multidrug resistance (SMR)-type efflux pump, is highly conserved in R. anatipestifer strains and important for the multidrug resistance. In the present study, we characterized the GE296_RS02355 gene in R. anatipestifer strain LZ-01. First, the deletion strain RA-LZ01ΔGE296_RS02355 and complemented strain RA-LZ01cΔGE296_RS02355 were constructed. When compared with that of the wild-type (WT) strain RA-LZ01, the mutant strain ΔRanQ showed no significant influence on bacterial growth, virulence, invasion and adhesion, morphology biofilm formation ability, and glucose metabolism. In addition, the ΔRanQ mutant strain did not alter the drug resistance phenotype of the WT strain RA-LZ01 and displayed enhanced sensitivity toward structurally related quaternary ammonium compounds, such as benzalkonium chloride and methyl viologen, which show high efflux specificity and selectivity. This study may help elucidate the unprecedented biological functions of the SMR-type efflux pump in R. anatipestifer. Thus, if this determinant is horizontally transferred, it could cause the spread of quaternary ammonium compound resistance among bacterial species.

OmpA is involved in the invasion of duck brain microvascular endothelial cells by Riemerella anatipestifer.

Bacterial meningitis is a major cause of morbidity and mortality. Despite advances in antimicrobial chemotherapy, the disease remains detrimental to humans, livestock, and poultry. Riemerella anatipestifer is a gram-negative bacterium causing duckling serositis and meningitis. However, the virulence factors contributing to its binding and invasion of duck brain microvascular endothelial cells (DBMECs) and penetration of the blood-brain barrier (BBB) have never been reported. In this study, immortalized DBMECs were successfully generated and used as an in vitro-model of duck BBB. Furthermore, ompA gene deletion mutant of the pathogen and multiple complemented strains carrying the complete ompA gene and its truncated forms were constructed. Bacterial growth, invasion, and adhesion assays and animal experiments were performed. The results show that the OmpA protein of R. anatipestifer had no effect on bacterial growth and adhesion ability to DBMECs. The role of OmpA in the invasion of R. anatipestifer into DBMECs and duckling BBB was confirmed. The amino acids 230-242 of OmpA represents a key domain involved in R. anatipestifer invasion. In addition, another OmpA1164 protein constituted by the amino acids 102-488 within OmpA could function as a complete OmpA. The signal peptide sequence from amino acids 1-21 had no significant effect on OmpA functions. In conclusion, this study illustrated that OmpA is an important virulence factor mediating R. anatipestifer invasion of DBMECs and penetration of the duckling BBB.

Characterization of RaeE-RaeF-RopN, a putative RND efflux pump system in Riemerella anatipestifer.

Resistance-nodulation-division (RND) efflux systems are ubiquitous in Gram-negative bacteria and play a predominant role in antimicrobial resistance and other diverse phenotypes, but the knowledges of RND efflux systems are poorly understood so far in Riemerella anatipestifer. According to the sequence annotation, RIA_1117-RIA_1118-RIA_1119 operon in RA-GD strain encodes a putative tripartite RND efflux system. RIA_1117, RIA_1118 and RIA_1119 genes encode an outer member protein (OMP), an inner membrane pump protein (pump transporter), and a periplasmic membrane fusion protein (MFP), respectively. Furthermore, RIA_1119 protein is annotated as a MexE component. In this work, the biological functions of RIA_1117-RIA_1118-RIA_1119 proteins were studied. The antibiotic susceptibility testing showed that the inactivation of RIA_1117, RIA_1118 and RIA_1119 genes all raised susceptibility to amikacin, streptomycin and SDS. By induction with the above antimicrobial agents, the transcription levels of RIA_1117 and RIA_1118 genes were up-regulated significantly using qRT-PCR detection, but no significance difference was observed for the transcription level of RIA_1119 gene. CCCP inhibitor assay confirmed that RIA_1117, RIA_1118 and RIA_1119 proteins mediated amikacin, streptomycin and SDS resistance depending on proton motive force (PMF). Spot assay and streptomycin accumulation assay confirmed that RIA_1117, RIA_1118 and RIA_1119 proteins contributed to export streptomycin, and CCCP increased the accumulation of streptomycin. Furthermore, RIA_1117, RIA_1118 and RIA_1119 proteins also were involved in the fitness and virulence of RA-GD strain. These results showed that RIA_1117-RIA_1118-RIA_1119 operon encoded a RND efflux system, which has the substrate specificity for streptomycin, amikacin and SDS and contributed to the growth and virulence of RA-GD. RIA_1117-RIA_1118-RIA_1119 was designated RaeE-RaeF-RopN efflux system. Based on the above results and structural analysis, RIA_1117, RIA_1118 and RIA_1119 proteins corresponded to RopN (OMP), RaeF (pump transporter) and RaeE (MFP), respectively.

[Validity and reliability of the Chinese version of Mobile Phone Involvement Questionnaire in college students].

OBJECTIVE: To test the validity and reliability of the Chinese version of Mobile Phone Involvement Questionnaire (MPIQ) in college students. METHODS: We assessed the degree of phone dependence using the MPIQ among 2122 college students. One month later, 60 students were randomly selected for assessment with the MPIQ, and the ROC curve was generated to evaluate the true positive rate (sensitivity) and false positive rate at different cutoff values to determine the optimal cutoff score of the MPIQ. RESULTS: Among 98.9% of the participants who finished all the items, their MPIQ scores show a positive skew distribution and a one-factor structure. The load scores of the items ranged from 0.54 to 0.77. The Cronbach's α coefficient and the Spearman Brown split reliability were 0.84 and 0.83, respectively, the correlation coefficients between the items and total score ranged from 0.54 to 0.76, and the test-retest reliability was 0.48 (P < 0.001). At the optimal cut-off score of 32, the sensitivity and the specificity of the MPIQ were 0.634 and 0.652, respectively. CONCLUSIONS: At the optimal cut-off score of 32, the MPIQ has good validity and reliability for assessing phone dependence among college students.

RanB, a putative ABC-type multidrug efflux transporter contributes to aminoglycosides resistance and organic solvents tolerance in Riemerella anatipestifer.

Riemerella anatipestifer is a Gram-negative bacterium, which is an important pathogen infecting ducks and resistant to various antibiotics. The efflux pump is an important resistance mechanism of Gram-negative bacteria, but little research has been done in R. anatipestifer. In this study, the drug resistance mediated by RIA_1614 gene of R. anatipestifer RA-GD strain was studied, because the gene was presumed to be an efflux pump component of ABC. Firstly, the deletion strain RA-GD△RIA_1614 and complemented strain RA-GD△RIA_1614 pCPRA::RIA_1614 were constructed. Then, MICs of various antimicrobial agents to parent and deletion strains and the tolerance of the strains to organic solvents were detected to screen the substrates for RIA_1614 gene. Moreover, the transcription levels of RIA_1614 gene in the parent and the complemented strains exposed to the substrates were detected by quantitative real-time RT-PCR. Furthermore, the efflux abilities of parent, deletion and complemented strains to substrates were determined by antibiotic accumulation test. In addition, in vitro competition ability and virulence of the strains were also detected. The results showed that the deletion strain was more sensitive to aminoglycosides and organic solvents than parental strain RA-GD. When RA-GD and complemented strain were exposed to sub-repression levels of aminoglycosides and organic solvents, the transcription levels of RIA_1614 gene were significantly up-regulated. Sodium o-vanadate inhibitor assay confirmed that RIA_1614 protein contributed to amikacin and streptomycin resistance and organic solvent tolerance. Streptomycin accumulation test showed that the RIA_1614 protein was able to export streptomycin, and the addition of ATPase inhibitor sodium o-vanadate increased the accumulation of streptomycin, indicating that RIA_1614 protein was an ATP-dependent efflux transporter. Growth and competition experiments revealed that RIA_1614 protein had no significant effect on growth of RA-GD, but decreased in vitro competition ability of the strain. Furthermore, pathogenicity tests showed that RIA_1614 protein involved in the virulence of the strain. Based on the results and amino acid sequence analysis, it was determined that RIA_1614 protein was a member of ABC efflux pumps, and the protein was named RanB.

Identification of protein inhibitor of activated STAT 4, a novel host interacting partner that involved in bovine viral diarrhea virus growth.

BACKGROUND: Bovine viral diarrhea virus (BVDV) belongs to the Flaviviridae family and the pestivius virus group. BVDV is responsible for significant economic loss in cattle industry worldwide because of reducing reproductive performance, increasing incidence of other diseases and mortality among young stock. The core (C) protein of the Flaviviridae family member is involved in host antiviral immune response through activation of related signaling pathways that affect the viral replication. However, the influence of C protein-interaction partners in BVDV infections is poorly defined. METHODS: To explore C-protein-interacting partners, yeast two-hybrid was used to screen the interaction protein of C protein using bovine peripheral blood mononuclear cell (PBMC) cDNA library. The co-immunoprecipitation and confocal assays were manipulated to determine the interaction between potential partners and C protein. Knockdown and overexpression of the partner were used to examine whether the C-protein-interacting partner plays a role in BVDV proliferation and virulence. Meanwhile, qRT-PCR and western blot assays were used to investigate the effect of C protein and C-protein-interacting partner on the immune response of host cells. RESULTS: We identified protein inhibitor of activated STAT 4 (PIAS4) as a novel interacting partner of the BVDV C protein. Co-immunoprecipitation and confocal assays demonstrated a strong interaction between C protein and PIAS4. Silencing of PIAS4 with small interfering RNA suppressed C protein expression and BVDV growth, while overexpression of PISA4 increased C protein expression and BVDV growth. The overexpression of PIAS4 increased the cell apoptosis. Meanwhile, the expressions of STAT4, SOCS3, IFITM, IFN-α were negatively regulated by the expression of PIAS4. The expression of C protein suppressed the antiviral proteins expression, and the inhibition effect was enhanced by interaction of PIAS4 and C protein. These results highlighted the beneficial properties of cellular PIAS4 for BVDV protein expression and growth. CONCLUSIONS: This study provides reliable clues for understanding the roles of PIAS4 in the regulation of BVDV growth.

Evaluation of protective efficacy of inactivated Mycoplasma synoviae vaccine with different adjuvants.

Mycoplasma synoviae (MS) is a poultry pathogen with a reported distribution throughout the world. Vaccination is utilized as an important component of MS control programs for MS infection. The aim of this study was to evaluate protection efficacy of an inactivated MS vaccine (MS bacterin) with different adjuvants in broilers against a Chinese field isolate (CHN-BZJ2-2015). Vaccination with adjuvants ISA 71 VG and chitosan, respectively, enhanced specific lymphocyte proliferation responses and upregulated the expression of IL-1ß, IL-6, IL-2 and IFN-γ prior to challenge. Furthermore, vaccination with adjuvant ISA 71 VG elicited the highest antibody titers, exhibited significantly lower air sac, foot pad and tracheal lesions than the other groups (P < 0.05), and decreased MS colonization. These results demonstrated that inactivated MS vaccine with ISA 71 VG is able to induce both cellular and humoral immune response in broilers and confers a high level of protection upon challenge, demonstrating a potential application in the field.

Prevalence and Characteristics of Quinolone Resistance in Salmonella Isolated from Retail Foods in Lanzhou, China.

The aim of this study was to determinate the prevalence of Salmonella in retail foods and its resistance to quinolones in retail foods in Lanzhou, People's Republic of China. In this work, 2,182 food samples, collected from March 2015 to December 2018, were analyzed to detect Salmonella and then analyzed for serotype distribution, quinolone resistance, and quinolone-resistant gene detection. The findings demonstrate that the overall prevalence of Salmonella in these food categories was low. A total of 41 (1.9%) of 2,182 food samples were found to be positive for Salmonella. Ten distinct serovars were identified, and Salmonella Derby, Salmonella Anatum, and Salmonella Enteritidis were the most prevalent serovars. According to the broth microdilution test, the resistance percentages were 90.2% to nalidixic acid, 39.0% to enrofloxacin, 41.5% to ciprofloxacin, 29.3% to ofloxacin, and 26.8% to levofloxacin. Among the quinolone-resistant isolates, 12 strains had a single mutation in gyrA at codon 83 (Ser→Phe) or codon 87 (Asp→Asn or Asp→Gly). Five isolates had one parC mutation (Ser80→Arg) and one or two gyrA hot spot mutations. qnr genes were found in seven isolates (five qnrB and two qnrD), and the aac(6')-Ib gene in seven isolates. Two isolates carry both qnrB and aac(6')-Ib-cr genes. Based on these results, a low prevalence of Salmonella contamination in retail foods was found, but it might play a potential risk factor in the spread of quinolone-resistant Salmonella strains in the Lanzhou region.

[Association of mobile phone overuse with sleep disorder and unhealthy eating behaviors in college students of a medical university in Guangzhou].

OBJECTIVE: To investigate the association of mobile phone use with sleep disorder and unhealthy eating behavior among college students of a medical university in Guangzhou. METHODS: Mobile Phone Involvement Questionnaire (MPIQ), Pittsburgh Sleep Quality Index (PSQI) and the Three Factor Eating Questionnaire Revised 21 Item (TFEQ-R21) were used to survey 2122 undergraduates of the medical university. One-sample t test, One-way ANOVA and multiple linear regression analysis were used to analyze the data. RESULTS: Age, body mass index (BMI), phone use before sleep, phone use frequency, sleep quality (assessed by total PSQI score) and the dimension scores of TFEQ-R21 for uncontrolled eating, cognitive restraint, and emotional eating were all significantly correlated with the total score of MPIQ (P < 0.05). Phone use before sleep, high frequency of mobile phone use, poor sleep quality and emotional eating were associated with high MPIQ scores, while lower cognitive restraint and emotional eating tendency were correlated with lower scores of MPIQ. Bivariate analysis revealed that age (r=0.088, P < 0.001), BMI (r=0.055, P < 0.05), PSQI scores (r=0.204, P < 0.001), TFEQ-UE scores (r=0.199, P < 0.001), TFEQ-CR scores (r=-0.076, P < 0.001), TFEQ-EE scores (r=0.170, P < 0.001), phone use before sleep (r=0.429, P < 0.001), and phone use frequency (r=0.316, P < 0.001) were all significantly correlated with MPIQ scores; multiple linear regression analysis showed that model 4 incorporating the scores of TFEQ-UE, TFEQ-CR, and TFEQ-EE explained up to 21.8% of the main effect (adjusted R2= 21.5%). CONCLUSIONS: Mobile phone overuse is associated with poor sleep quality and unhealthy eating behaviors, and education and interventions for mobile phone use is essential among college students.

Interplay Between the Phenotype and Genotype, and Efflux Pumps in Drug-Resistant Strains of Riemerella anatipestifer.

The number of multidrug-resistant strains of Riemerella anatipestifer continues to increase, and new strategies for the treatment of associated infections are necessary. Recently, numerous studies have shown that efflux pumps (EPs) play key roles in universal bacterial mechanisms that contribute to antibiotic resistance. In addition, studies have shown that the effects of antibiotics that are subjected to efflux can be reinforced by their combined use with efflux pump inhibitors (EPIs). Unfortunately, the role of the efflux system in R. anatipestifer remains barely understood. In this study, we evaluated the role of EPs and resistance genes in the resistance generated by clinical strains of R. anatipestifer to antibiotics. A set of 10 R. anatipestifer strains were characterized by drug resistance, associated resistance genes, and antibiotic profiles in the presence and absence of EPIs. Efflux activity was studied on a real time basis through a fluorometric method. Quantification of the levels of mRNA transcription of efflux pump genes (EPGs) was determined by RT-qPCR. Several approaches (detection of resistance genes, drug susceptibility testing, and growth kinetics analysis) were used to assess the correlation between the effect of the EPIs and the resistance levels. Analysis of the R. anatipestifer growth inhibition tests showed that the antibiotic activity was enhanced by the synergy of EPIs. Among the various resistance genes that confer antibiotic resistance, different minimum inhibitory concentrations (MICs) were observed. The different levels of resistance were reduced by EPIs. Real time fluorometry showed that all the R. anatipestifer strains presented inherent efflux activity, conferring varying levels of inhibition in the presence of EPIs. Moreover, 15 EPGs were overexpressed in the presence of antibiotics. The addition of EPIs to antibiotics led to downregulation in the expression of some EPGs and a simultaneous increase in drug resistance and sensitivity. These results demonstrated the contribution of these EPs in the resistant phenotype of the clinical strains of R. anatipestifer that are under investigation, independently of the resistant genotype of the respective strains. Intrinsic efflux activity was possibly linked to the evolution of resistance in multidrug-resistant isolates of R. anatipestifer. Furthermore, the inhibition of EPs by EPIs could enhance the clinical effects of antibiotics.

Threshold level of Riemerella anatipestifer crossing blood-brain barrier and expression profiles of immune-related proteins in blood and brain tissue from infected ducks.

Riemerella anatipestifer (R. anatipestifer) is a Gram-negative bacterium that crosses the blood-brain barrier (BBB) and causes meningitis with neurological symptoms in infected ducks. A threshold level of bacteremia must be reached before the BBB can be breached. In this study, the bacterial burden and expression profiles of immune-related proteins in blood and brain tissue samples from R. anatipestifer-infected ducks were investigated. The data showed that R. anatipestifer could cross the BBB with low-level bacteremia of 7.5 × 102 CFU/ml in infected blood. Analysis of immune-related proteins revealed that IL-4, IL-17A, IL-17D, TLR3, TLR4, TLR7, and TGF-ß in blood, as well as IL-1ß, IL-2, IL-4, IL-17A, IL-17D, IL-17F, TLR3, TLR4, and TGF-ß in brain tissue were upregulated at an early stage in infection. The expression levels of Th1 and Th17-specific cytokines were significantly higher than those of Th2-specific cytokines, which indicated that mainly Th1 and Th17 immune responses were induced during R. anatipestifer infection.

Complete genome sequence of a bovine ephemeral fever virus JT02L strain in mainland China.

In this study, we report the complete genome sequence of bovine ephemeral fever virus (BEFV) JT02L, which has been used in our laboratory, in mainland China, for more than a decade. The genome is 14941 nucleotide (nt), comprising a leader sequence of 50 nt, nucleoprotein (N) gene of 1328 nt, phosphoprotein (P) gene of 858 nt, matrix protein (M) gene of 691 nt, glycoprotein (G) gene of 1897 nt, non-structural glycoprotein (GNS) gene of 1785 nt, α1α2 gene of 638 nt, ß gene of 460 nt, γ gene of 400 nt, large multi-functional enzyme (L) gene of 6470 nt and a trailer sequence of 73 nt. Individual genes are separated by intergenic regions (IGRs) of 26, 44, 47, 51, 37, 39, 68 and -21 nt respectively. The overall organization is similar to an Australian BEFV isolate BB7721 but demonstrates some distinctive features including longer α3 and ß open reading frames, intact termination/polyadenylation (TTP) sequence downstream of the ß open reading frame and a longer ß-γ IGR integrated with a 38 nt AT-rich fragment. To our knowledge, this is the first report describing the complete genome of a BEFV strain of East Asian lineage, which may facilitate studies on genomic diversity among geographic strains of BEFV in China and the world.

Large-scale serological survey of bovine ephemeral fever in China.

Bovine ephemeral fever (BEF) is caused by the arthropod-borne bovine ephemeral fever virus (BEFV), which is classified in the family Rhabdoviridae and the genus Ephemerovirus. A debilitating and sometimes fatal viral disease, BEF affects cattle and water buffalo. The epizootiology of BEF among cattle in China has not been fully determined. We examined the seroprevalence of the BEFV among cattle in China between January 2012 and June 2014. Among the 2822 serum samples collected from various cattle breeds in 26 provinces in China, the seropositive rate for the BEFV ranged from 0% to 81% between regions and species. Our findings show that BEFV was prevalent in the all of the regions tested in our study and provide the first reliable reference regarding BEF surveillance in China.

Molecular investigation of bovine viral diarrhea virus infection in yaks (Bos gruniens) from Qinghai, China.

BACKGROUND: Bovine viral diarrhea virus (BVDV) is a pestivirus which infects both domestic animals and wildlife species worldwide. In China, cattle are often infected with BVDV of different genotypes, but there is very limited knowledge regarding BVDV infection in Chinese yaks and the genetic diversity of the virus. The objectives of this study were to detect viral infection in yaks in Qinghai, China and to determine the genotypes of BVDV based on analysis of the 5'untranslated region (5'UTR) and N-terminal protease (N(pro)) region. RESULTS: Between 2010 and 2012, 407 blood samples were collected from yaks with or without clinical signs in six counties of Qinghai Province. Ninety-eight samples (24%) were found to be positive by reverse transcription polymerase chain reaction (RT-PCR) targeting a conserved region of BVDV-1 and BVDV-2. The nucleotide sequences of the 5'UTR and complete N(pro) region were determined for 16 positive samples. Phylogenetic reconstructions demonstrated that all 16 samples belong to subgenotypes BVDV-1b, BVDV-1d and BVDV-1q. CONCLUSIONS: This study provides, for the first time, molecular evidence for BVDV infection in yaks in Qinghai involving multiple subgenotypes of BVDV-1. This may have occurred under three possible scenarios: interspecies transmission, natural infection, and the use of vaccines contaminated with BVDV. The results have important implications for yak production and management in China, and specifically indicate that unscientific vaccination practices should be stopped and bio-security increased.

Seroprevalence of Chlamydophila abortus infection in yaks (Bos grunniens) in Qinghai, China.

Chlamydophila abortus is an important amphixenosis which in a wide range of animals, associated with reproductive disorders in yaks. In order to assess the prevalence of this infection in yaks in Qinghai, China, a cross-sectional study was carried out, and a total of 674 serum samples were collected from June to October 2012 in six counties, and antibodies to C. abortus were examined by indirect hemagglutination (IHA) test. The overall seroprevalence of C. abortus in yaks was 17.66 % (119/674), and the seroprevalence of antibodies to C. abortus in yaks ranged from 11.82 to 28.43 % among the six different areas, and the difference was statistically significant (P < 0.05). The seropositivity of C. abortus infection in different age groups varied from 16.33 to 18.49 %, and prevalence in yaks of ≥3 year (18.49 %) was slightly higher than that in yaks of <3 year, but the differences among the age groups were not statistically significant (P > 0.05). The seroprevalence of C. abortus infection in male yak (16.8 %) was slightly lower than that in females (17.85 %), and the difference was not statistically significant (P > 0.05). So far, this is the first systematic and comprehensive investigation of C. abortus infectionin in yaks in this area.

Infection of mouse bone marrow-derived immature dendritic cells with classical swine fever virus C-strain promotes cells maturation and lymphocyte proliferation.

In this study, the interactions of classical swine fever virus (CSFV) C-strain and the virulent GSLZ strain with mouse bone marrow-derived immature dendritic cells (BM-imDCs) were investigated for the first time. Both the C-strain and the virulent GSLZ strain could effectively infect and replicate in mouse BM-imDCs. C-strain-infected BM-imDCs showed a greatly enhanced degree of maturation, and could effectively promote the expansion and proliferation of allogeneic naive T cells. The C-strain induced a stronger Th1 response. Infection with the virulent GSLZ strain had no obvious influence on cell maturation or lymphocyte proliferation, and failed to induce any obvious immune response. The results of this study provided initial information for research of the immunologic mechanisms of CSFV using mouse DCs as the model cells.

Identification and characterization of a novel subgenotype of bovine viral diarrhea virus isolated from dairy cattle in Northwestern China.

Bovine viral diarrhea virus (BVDV) was detected by RT-PCR in 105 out of 391 samples which were collected from five dairy farms in Ningxia, China during 2010-2011. Non-cytopathogenic BVDV was isolated from 13 samples and a 230-bp fragment of the 5'-untranslated region was amplified and sequenced. While the predominant subgenotypes were BVDV-1b and BVDV-1d, a potentially novel subgenotype was identified by phylogenetic analysis, which may have implications for vaccine development.

Phylogenetic relationships of the glycoprotein gene of bovine ephemeral fever virus isolated from mainland China, Taiwan, Japan, Turkey, Israel and Australia.

BACKGROUND: The glycoprotein (G) gene sequences of bovine ephemeral fever virus (BEFV) strains derived from mainland China have not been compared with those of the isolates from other countries or areas. Therefore, the G genes of four BEFV isolates obtained from mainland China were amplified and sequenced. A phylogenetic tree was constructed in order to compare and analyze the genetic relationships of the BEFV isolates derived from mainland China and different countries and areas. RESULTS: The complete BEFV G gene was successfully amplified and sequenced from four isolates that originated from mainland China. A total of fifty-one BEFV strains were analyzed based on the G gene sequence and were found to be highly conserved. A phylogenetic tree showed that the isolates were grouped into three distinct lineages depending on their source of origin. The antigenic sites of G1, G2 and G3 are conserved among the isolates, except for several substitutions in a few strains. CONCLUSIONS: The phylogenetic relationships of the BEFV isolates that originated from mainland China, Taiwan, Japan, Turkey, Israel and Australia were closely related to their source of origin, while the antigenic sites G1, G2 and G3 are conserved among the BEFV isolates used in this work.