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Refractory high entropy alloys (HEAs) have been identified as potential candidates for reinforcement phases in metal matrix composites due to their excellent thermal stability, good strength and toughness. This investigation reports on the synthesis of a Cu-6%Ag composite reinforced with refractory NbTaMoW HEA powder. The composite was fabricated using a three-step process that involves mechanical alloying (MA), melting and casting, and cold drawing deformation. The resulting composite was analyzed for particle distribution, hardness and electrical conductivity, while its microstructure was examined using scanning electron microscopy (SEM). Results revealed that a single bcc phase of the HEA powder was formed with a nanocrystalline size of 6.22 nm after MA. The synthesized alloy after casting revealed no significant macroscopic segregation, with the Ag phase and HEA particles evenly dispersed throughout the alloy solidification structure. Cold drawing the alloy resulted in a hardness of 163HV and a conductivity of 77%IACS. Compared to the Cu-6%Ag alloy prepared by the conventional method, the alloy showed a 16.4% increase in hardness and a 3.7% decrease in conductivity. This study demonstrated the potential of doped HEA powders to enhance the mechanical properties of Cu matrix alloys to produce composites with improved properties. [ABSTRACT FROM AUTHOR]

In this paper, probabilistic quantization on Unbiased Broadcast Gossip Algorithms (UBGA) is introduced to adapt to the limited bandwidth of distributed network channels. This innovative quantized consensus algorithm is called Quantized UBGA (QUBGA). By briefly describing the graph and time model, and reviewing UBGA, it is proved that QUBGA can converge in expectation and in the second moment for strongly connected digraphs. Furthermore, it is proved that the convergence rate of QUBGA is related to quantized resolution and topology structure. Performance analysis results are consistent with theoretical analysis. [ABSTRACT FROM AUTHOR]

Monitoring the vibration of the painting canvas during transport is of great significance to protect paintings from damage. However, limited to the narrow structure of the transport crate, the lack of an inertial reference, and the limitations to attach sensors to the canvas, this is a difficult task. For this reason, based on vibration data measured on the strainer that is easily obtained during transport, this contribution proposes to reproduce these with high accuracy in the laboratory. There, the resulting vibration of the canvas can be conveniently observed in a controlled environment with respect to an inertial reference. A real-time simulation platform based on the multi-channel Filtered-x Least Mean Square (FxLMS) algorithm controls four actuators simultaneously and reproduces the vibration of the strainer obtained from a real transport experiment. The vibration of the canvas is then measured by a laser Doppler vibrometer without contact. The experimental results show that the vibration reproduction system has sufficient reproduction accuracy for the vibration response. Even though some overshoot in the reproduced acceleration can be observed in some cases, the overall reproduction is very good. A long-term reproduction experiment verifies its stable reproducibility. Therefore, the designed vibration reproduction system provides a reference for the unknown canvas response during transport, and further helps art conservators to evaluate the transport process of the painting. [ABSTRACT FROM AUTHOR]

In the traditional transportation of paintings and the design of the packaging systems, paintings are usually assumed to behave like a linear system. In order to verify this hypothesis, in this contribution, by means of a hammer experiment and a sweep excitation experiment to simulate the shock and vibration during transportation, respectively, the modal nonlinearities of two real paintings and a dummy painting are experimentally studied. The experimental results show that paintings can be treated as a linear system only when being subjected to shock, but the modal nonlinearities of paintings cannot be ignored when being subjected to vibration. The general behaviour of the paintings modal nonlinearities is then summarised based on experimental results, and their consequences for painting transportation are discussed. First of all, the offset of the resonance frequency is the most important problem which will lead to failure of the original vibration isolation measures. Further, the decrease in the resonance peak amplitude will increase the probability of the eigenmode being excited. Besides, it is also necessary to attenuate the harmonic vibrations of paintings. Lastly, the different modal characteristics obtained by a sweep with increasing and decreasing frequency make the analysis of different excitation schemes more complicated. Therefore, the identification of the paintings modal nonlinearities is necessary and important. [ABSTRACT FROM AUTHOR]

A new Samarskii domain decomposition method for solving two-dimensional convection–diffusion equations is proposed. In this procedure, interface values between subdomains are computed by the Saul'yev asymmetric difference schemes based on Samarskii scheme; interior values are calculated by the Samarskii scheme. The new algorithm obtains accuracy of Samarskii scheme while maintaining parallelism and unconditional stability. Numerical examples show the accuracy and parallel efficiency of the new algorithm. [ABSTRACT FROM AUTHOR]

Main conclusion: After tobacco topping, changes in the auxin content could affect K+ uptake by inhibiting the activity of K+ uptake-related genes through the NtARF genes, thus causing changes in K+ content. Tobacco (Nicotiana tabacum) is a valuable industrial and commercial crop, and the leaf is its primary product. Topping (removing apical buds) is a common agronomic practice that significantly improves the yield of tobacco leaves. Potassium (K+) plays an important physiological role in tobacco growth and leaf traits, including combustibility, aroma, and safety in cigarette products, and its levels are significantly decreased after topping. Here, to present global spatial–temporal gene expression profiles and gene regulatory networks of the core elements of K+ uptake, leaves and roots from topped and untopped plants at short- and long-term time points after topping were sampled for transcriptome analysis. We found that the wounding response was initiated in leaves in the early stages after topping. Then, in the long term, processes related to metabolism and transcription regulation, as well as ion binding and transport, were altered. The expression profiles showed that core elements of K+ uptake and xylem loading were drastically suppressed in roots after topping. Finally, transient expression experiments confirmed that changes in the auxin content could affect K+ uptake by inhibiting the activity of K+ uptake-related genes through the tobacco auxin response factor (NtARF) genes, thus causing changes in the K+ content. These results suggest that some ARFs could be selected as targets to enhance the expressions of K+ uptake transporters, leading to increment of K+ contents and improvement of leaf quality in tobacco breeding. [ABSTRACT FROM AUTHOR]

In this study, we expressed rAvBD1-2–6-13 protein through Lactococcus lactis NZ3900, and the effects of the recombinant L. lactis NZ3900 as an immune enhancer and immune adjuvant were verified using in vivo and in vitro tests. In vitro tests revealed that recombinant L. lactis NZ3900 significantly activated the NF-κB signaling pathway and IRF signaling pathway in J774-Dual™ report cells and significantly increased the transcript levels of IL-10, IL-12p70, CD80, and CD86 in chicken PBMCs and chicken HD11 cells. In vivo experiments revealed that the immunized group supplemented with recombinant L. lactis NZ3900 as an adjuvant had significantly higher serum antibody titers and higher proliferative activity of PBMCs in the blood of the chickens immunized with NDV live and inactivated vaccines. Our study shows that the recombinant L. lactis NZ3900 has strong immunomodulatory activity both in vivo and in vitro and is a potential immune enhancer. Our work lays the foundation for the research and development of new animal immune enhancers for application in the poultry industry. [ABSTRACT FROM AUTHOR]

Key message: NtARF6 overexpression represses nicotine biosynthesis in tobacco. Transcriptome analysis suggests that NtARF6 acts as a regulatory hub that connect different phytohormone signaling pathways to antagonize the jasmonic acid-induced nicotine biosynthesis. Plant specialized metabolic pathways are regulated by a plethora of molecular regulators that form complex networks. In Nicotiana tabacum, nicotine biosynthesis is regulated by transcriptional activators, such as NtMYC2 and the NIC2-locus ERFs. However, the underlying molecular mechanism of the regulatory feedback is largely unknown. Previous research has shown that NbARF1, a nicotine synthesis repressor, reduces nicotine accumulation in N. benthamiana. In this study, we demonstrated that overexpression of NtARF6, an ortholog of NbARF1, was able to reduce pyridine alkaloid accumulation in tobacco. We found that NtARF6 could not directly repress the transcriptional activities of the key nicotine pathway structural gene promoters. Transcriptomic analysis suggested that this NtARF6-induced deactivation of alkaloid biosynthesis might be achieved by the antagonistic effect between jasmonic acid (JA) and other plant hormone signaling pathways, such as ethylene (ETH), salicylic acid (SA), abscisic acid (ABA). The repression of JA biosynthesis is accompanied by the induction of ETH, ABA, and SA signaling and pathogenic infection defensive responses, resulting in counteracting JA-induced metabolic reprogramming and decreasing the expression of nicotine biosynthetic genes in vivo. This study provides transcriptomic evidence for the regulatory mechanism of the NtARF6-mediated repression of alkaloid biosynthesis and indicates that this ARF transcription factor might act as a regulatory hub to connect different hormone signaling pathways in tobacco. [ABSTRACT FROM AUTHOR]

Chicken infectious anemia (CIA), caused by chicken anemia virus (CAV), is an important immunosuppressive disease that seriously threatens the global poultry industry. Here, we isolated and identified 30 new CAV strains from CAV-positive flocks. The VP1 genes of these strains were sequenced and analyzed at the nucleotide and amino acid levels and were found to have very similar nucleotide sequences (> 97% identity); however, they showed 93.9–100.0% sequence identity to the VP1 genes of 55 reference strains. Furthermore, alignment of the deduced amino acid sequences revealed some unique mutations. Phylogenetic analysis indicated the division of VP1 amino acid sequences into two groups (A and B) and four subgroups (A1, A2, A3 and A4). Interestingly, 22 of the newly isolated strains and some Asian reference strains belonged to the A1 group, whereas the remaining eight new isolates belonged to the A3 group. To evaluate the pathogenicity of the epidemic CAV strains from China, the representative strains CAV-JL16/8901 and CAV-HeN19/3001 and the reference strain Cux-1 were selected for animal experiments. Chickens infected with the isolates and reference strain all showed thymus atrophy and bone marrow yellowing. The mortality rates for CAV-JL16/8901, CAV-HeN19/3001, and the reference strain was 30%, 20%, and 0%, respectively, indicating that the epidemic strains pose a more serious threat to chickens. We not only analyzed the molecular evolution of the epidemic strains but also showed for the first time that the epidemic strains in China are more pathogenic than reference strain Cux-1. Effective measures should be established to prevent the spread of CIA in China. [ABSTRACT FROM AUTHOR]

Avian leukosis virus subgroup J (ALV-J) is an important pathogen for various neoplasms and causes significant economic losses in the poultry industry. Serological detection of specific antibodies against ALV-J infection is important for successful clinical diagnosis. Here, a 293F stable cell line was established to stably express gp85 protein. In this cell line, gp85 protein was expressed at approximately 30 mg/L. A subgroup-specific indirect enzyme-linked immunosorbent assay (iELISA) was developed using ALV-J gp85 protein as coated antigen to detect antibodies against ALV-J. The sensitivity of the iELISA (1:51200 diluted in serum) was 16 times more than that of indirect immunofluorescence assay (IFA; 1:3200 diluted in serum). Moreover, there was no crossreactivity with antibodies against other common avian viruses and other avian leukosis virus subgroups, such as subgroups A and B. The practicality of the iELISA was further evaluated by experimental infection and clinical samples. The results from experimental infection indicated that anti-ALV-J antibodies were readily detected by iELISA as early as 4 weeks after ALV-J infection, and positive antibodies were detected until 20 weeks, with an antibody-positive rate of 11.1% to 33.3%. Moreover, analysis of clinical samples showed that 9.49% of samples were positive for anti-ALV-J antibodies, and the concordance rate of iELISA and IFA was 99.24%. Overall, these results suggested that the subgroup-specific iELISA developed in this study had good sensitivity, specificity, and feasibility. This iELISA will be very useful for epidemiological surveillance, diagnosis, and eradication of ALV-J in poultry farms. [ABSTRACT FROM AUTHOR]

Since 2015, outbreaks of hepatitis-hydropericardium syndrome (HPS) caused by a novel genotype of fowl adenovirus 4 (FAdV-4) infection have created serious economic losses in China. Given that other serotypes of hypervirulent FAdVs have also been reported in poultry around the world, a common ELISA for all serotypes within the group I fowl adenoviruses (FAdV-I) is urgently needed, especially for clinical epidemic serotypes. In this study, we used high purity and concentration virions of FAdV-4 and developed a common ELISA for detecting antibodies against 12 FAdV-I serotypes. The developed ELISA was able to distinguish between antibodies against FAdV-I, FAdV-III, and other heterologous viruses without any cross-reaction. Furthermore, the ELISA showed higher sensitivity than the FAdV-1-based ELISA to the novel FAdV-4 found in China. Moreover, since there are no commercial vaccines against FAdVs in China, the ELISA was applied to detect sera samples from specific pathogen-free chickens inoculated with inactivated FAdV-1, FAdV-4, and FAdV-8a. The assay showed high sensitivities for all three detected serotypes within FAdV-I. In conclusion, a novel, common ELISA for FAdV-I was developed in this study and could be a powerful tool for seroepidemiological investigations and FAdVs vaccine development. [ABSTRACT FROM AUTHOR]

Avian leukosis virus (ALV) caused tremendous economic losses to poultry industry all over the world, especially in China. One natural recombinant ALV strain, designated as HB2015032, was isolated from indigenous chickens with neoplastic diseases in Hubei, China. The complete proviral genome of HB2015032 is 7703 bp in length. Sequence analysis showed that the Env of HB2015032 exhibited 99.3% similarity with that of a ALV subgroup K (ALV-K) isolate JS11C1 at amino acid level. Phylogenetic analysis revealed that both gp85 and gp37 of HB2015032 were clustered in the same branch with JS11C1 and other ALV-K strains isolated from Chinese indigenous chickens in recent years. However, the pol gene, the 3′ untranslated region (3′ UTR), and the 3′ long terminal repeat (3′ LTR) of HB2015032 were more closely related to ALV-J prototype HPRS-103, and clustered in the same branch with ALV-J strains. Furthermore, the pol gene of HB2015032 contained a premature stop codon that resulted in a truncated Pol protein with 22 amino acid residues missing, which was a unique feature of the pol gene of ALV-J. 3′UTR of HB2015032 containing entire DR1, E element and U3. E element of HB2015032 contained one base deletion, which resulted in a c-Ets-1 binding site. In addition, U3 region of HB2015032 contains most of the transcription regulatory elements of ALV-J, including two CAAT boxes, Y boxes, CArG boxes, PRE boxes, NFAP-1 boxes, and one TATA box. These results suggest that isolate HB2015032 was a novel recombinant ALV-K containing the ALV-K env gene and the ALV-J backbone and exhibiting high pathogenicity. [ABSTRACT FROM AUTHOR]

Spectrum sensing plays a foundational role in cognitive radio sensor networks. However, only the methods with low computational complexity can be utilized due to energy restriction of sensor node. To this end, a novel frequency-domain spectrum sensing method is presented to satisfy corresponding requirements of cognitive radio sensor networks. Only the maximum value of power spectrum density is utilized as test statistic to reduce the computational complexity. According to the dependence of 2L real parts and imaginary parts of the maximum value of power spectrum density, we model the maximum value of power spectrum density as the central Chi-square distribution for the H 0 case and non-central Chi-square distribution for the H 1 case. Exploiting resulting distributions, we derive the analytic expressions for the detection probability and the false-alarm probability. Additionally, the computational complexity of the proposed method is quantitatively analyzed. Finally, we certify the proposed test statistic and the probability distribution of the maximum value of power spectrum density and evaluate the impact of some parameters on the detection performance experimentally. The theoretical analysis and simulation results demonstrate that the proposed algorithm can offer high performance gains over the existing time-domain detection method. [ABSTRACT FROM AUTHOR]

Avian leukosis virus (ALV) is an avian oncogenic retrovirus that induces leukemia-like proliferative diseases in chickens. ALV infection can result in the development of immunological tolerance and persistent viremia. Since effective vaccines against ALV are not yet available, its current prevention primarily depends on detection and eradication to establish exogenous ALV-free poultry flocks. In this study, a rapid and simple colloidal gold test strip method, specific for the group-specific antigen, p27 protein, was developed and systematically evaluated for the detection of ALV from different samples. The detection limit of this assay was as low as 6.25 ng/ml for p27 protein and 80 TCID50/ml for different subgroups of ALV. Besides, the test strip showed high specificity in the detection of different subgroups of ALV, including ALV-A, ALV-B, ALV-J, and ALV-K, with no cross-reaction with other avian pathogens. Furthermore, we artificially infected specific pathogen-free (SPF) chickens with ALV-J, collected cloacal swabs, and examined viral shedding using both test strips and ELISA. Results from the test strip were highly consistent with that from ELISA. In addition, 1104 virus isolates from anti-coagulant blood samples, 645 albumen samples, and 4312 meconium samples were tested, and the test strip results agreed with those of ELISA kit up to 97.1%. All the results indicated that the colloidal gold test strip could serve as a simple, rapid, sensitive, and specific diagnostic method for eradication of ALV in poultry farms. [ABSTRACT FROM AUTHOR]

The diseases associated with fowl adenovirus (FAdV) infection, such as inclusion body hepatitis (IBH), hepatitis-hydropericardium syndrome (HPS), and gizzard erosion (GE), were first reported in Pakistan in 1987, and subsequent outbreaks have been reported worldwide, especially in China, where severe outbreaks of HPS with high mortality from 30 to 100% were recently reported and resulted in significant economic losses to the poultry industry. The diagnosis methods of FAdVs were mostly limited to the nucleotide sequence of hexon by PCR and DNA sequencing. The aim of this study was to generate B cell epitope maps of the species- and serotype-specific hexon L1 using monoclonal antibodies (mAbs) and bioinformatics tools for the development of novel diagnostic methods. In this study, the hexon L1 (230 amino acids) was expressed and used to generate 10 mAb-expressing hybridoma cell lines against the relative protein peptide. Subsequently, we defined the linear peptide epitopes recognized by these mAbs using a series of partially overlapping peptides derived from the FAdV-C hexon protein amino acid sequence to map mAbs reactivity. Finally, a common B cell epitope (31PLAPKESMFN40) for all species FAdVs and two FAdV-C-specific epitopes (79KISGVFPNP87 and 181DYDDYNIGTT190) were identified. These mAbs and their defined epitopes may support the development of the universal or species-specific differential diagnostic methods of FAdVs. [ABSTRACT FROM AUTHOR]

Avian leukosis virus (ALV) is an avian oncogenic retrovirus that can induce various clinical tumors. The capsid protein P27 is the group-specific antigen of ALV and has many viral antigen sites that are easy to detect. In this study, we produced a monoclonal antibody (mAb), 3A9, that is specific for the P27 protein. A series of partially overlapping peptides were screened to define PPSAR as the minimal linear epitope recognized by mAb 3A9. The identified epitope could be recognized by chicken anti-ALV and mouse anti-ALV P27 sera. The epitope was highly conserved among a number of ALV-A, ALV-B and ALV-J strains. MAb 3A9 might be a valuable tool for the development of new immunodiagnostic approaches for ALV, and the defined linear epitope might help further our understanding of the antigenic structure of the P27 protein. [ABSTRACT FROM AUTHOR]

To test whether amino acid mutations in the P and P loops of VP2 are involved in the replication and virulence of infectious bursal disease virus (IBDV), a pair of viruses, namely the moderately virulent IBDV (rGx-F9VP2) and the attenuated strain (rGt), were used. Residue mutations A222P (P) and S330R (P), selected by sequence comparison, were introduced individually into rGx-F9VP2 by using a reverse genetics system. In addition, the reverse mutation of either P222A or R330S was introduced into rGt. The four modified viruses were then rescued and evaluated in vitro (CEF cells) and in vivo (SPF chickens). Results showed that A222P elevated the replication efficiency of rGx-F9VP2 while P222A reduced that of rGt in CEF cells. A mutation at residue 330 did not alter IBDV replication. In addition, animal experiments showed that a single mutation at either residue 222 or 330 did not significantly influence the virulence of IBDV. In conclusion, residue 222 in P of VP2 is involved in the replication efficiency of IBDV in vitro but does not affect its virulence in vivo, further facilitating our understanding of the gene-function of IBDV. [ABSTRACT FROM AUTHOR]

The entry of enveloped viruses into host cells requires the fusion of viral and cell membranes. These membrane fusion reactions are mediated by virus-encoded glycoproteins. In the case of avian metapneumovirus (aMPV), the fusion (F) protein alone can mediate virus entry and induce syncytium formation in vitro. To investigate the fusogenic activity of the aMPV F protein, we compared the fusogenic activities of three subtypes of aMPV F proteins using a TCSD assay developed in this study. Interestingly, we found that the F protein of aMPV subtype B (aMPV/B) strain VCO3/60616 (aMPV/vB) was hyperfusogenic when compared with F proteins of aMPV/B strain aMPV/f (aMPV/fB), aMPV subtype A (aMPV/A), and aMPV subtype C (aMPV/C). We then further demonstrated that the amino acid (aa) residue 149F contributed to the hyperfusogenic activity of the aMPV/vB F protein. Moreover, we revealed that residue 149F had no effect on the fusogenic activities of aMPV/A, aMPV/C, and human metapneumovirus (hMPV) F proteins. Collectively, we provide the first evidence that the amino acid at position 149 affects the fusogenic activity of the aMPV/B F protein, and our findings will provide new insights into the fusogenic mechanism of this protein. [ABSTRACT FROM AUTHOR]

Reticuloendotheliosis virus (REV) causes an immunosuppressive and oncogenic disease in chickens and other birds. In this study, based on an infectious clone of REV, named HLJR0901, a recombinant virus containing the enhanced green fluorescence protein (EGFP) gene was constructed by inserting the EGFP expression cassette downstream of the 3′ terminus of the viral env gene. An EGFP-tagged REV that stably expresses EGFP was rescued. This visible recombinant REV could contribute to the further understanding of the molecular mechanism involved in the replication and pathogenicity of REV. [ABSTRACT FROM AUTHOR]

Avian leukosis virus subgroup J (ALV-J) is an avian oncogenic retrovirus that has caused severe economic losses in China. Gp85 protein is the main envelope protein and the most variable structural protein of ALV-J. It is also involved in virus neutralization. In this study, a specific monoclonal antibody, 4A3, was produced against the ALV-J gp85 protein. Immunofluorescence assays showed that 4A3 could react with different strains of ALV-J, including the British prototype isolate HPRS103, the American strains, an early Chinese broiler isolate, and layer isolates. A linear epitope on the gp85 protein was identified using a series of partially overlapping fragments spanning the gp85-encoding gene and subjecting them to western blot analysis. The results indicated that AEAELRDFI was the minimal linear epitope that could be recognized by mAb 4A3. Enzyme-linked immunosorbent assay (ELISA) revealed that chicken anti-ALV-J sera and mouse anti-ALV-J gp85 sera could also recognize the minimal linear epitope. Alignment analysis of amino acid sequences indicated that the epitope was highly conserved among 34 ALV-J strains. Furthermore, the epitope was not conserved among subgroup A and B of avian leukosis virus (ALV). Taken together, the mAb and the identified epitope may provide valuable tools for the development of new diagnostic methods for ALV-J. [ABSTRACT FROM AUTHOR]

The J-subgroup avian leukosis virus (ALV-J) strain WB11098J was isolated from a wild Eurasian teal, and its proviral genomic sequences were determined. The complete proviral sequence of WB11098J was 7868 nt long. WB11098J was 95.3.9 % identical to the prototype strain HPRS-103, 94.2 % identical to the American strain ADOL-7501, 94.5-94.7 % identical to Chinese broiler isolates, 94.8-97.5 % identical to layer chicken isolates, and 94.4-95.0 % identical to Chinese local chicken isolates at the nucleotide level. Phylogenetic analysis showed that the WB11098J isolate shared the greatest homology with the layer strain SD09DP03 and was included in the same cluster. Interestingly, two 19-bp insertions in the U3 regions of the 5′LTR and 5′UTR that were most likely derived from other retroviruses were found in the WB11098J isolate. These insertions separately introduced one E2BP-binding site in the U3 region of the 5′LTR and a RNA polymerase II transcription factor IIB and core promoter motif of ten elements in the 5′UTR. A 5-bp deletion was identified in the U3 region of the 5′LTR. No nucleotides were deleted in the rTM or DR-1 regions in the 3′UTR. A 1-bp deletion was detected in the E element and introduced a specific and distinct binding site for c-Ets-1. Our study is the first to report the molecular characteristics of the complete genome of an ALV-J that was isolated from a wild bird and will provide necessary information for further understanding of the evolution of ALV-J. [ABSTRACT FROM AUTHOR]

Reticuloendotheliosis virus (REV) causes an oncogenic, immunosuppressive and runting syndrome in many avian hosts worldwide. REV infection has never been reported in mallard ducks, however. To identify REV infection in mallards, we collected 40 mallard duck samples from Jilin Province of China. In this study, the REV strain, DBYR1102, was first isolated from a mallard in China and identified by PCR, indirect immunofluorescence assay and electron microscopy. The gp90 gene and complete LTR of DBYR1102 were amplified and sequenced. Phylogenetic analysis based on gp90 genes of REV indicated that the REV strain DBYR1102 is closely related to strain HLJR0901 from northeastern China, the prairie chicken isolate APC-566, and REV subtype III, represented by chick syncytial virus. This new strain is distantly related to two other subtypes of REV, 170A and SNV. Phylogenetic analysis based on the LTR yielded information similar to that obtained with the gp90 genes. The results of this study not only expand our epidemiological understanding of REV in the wild birds of China but also demonstrate the potential role of wild waterfowl in REV transmission. [ABSTRACT FROM AUTHOR]

Avian leukosis virus subgroup J (ALV-J), first isolated in 1989, preferentially infects meat-type birds. Chinese layer flocks have experienced outbreaks of this virus since 2008. To analyze the status of ALV-J infection in wild birds in China, 585 wild birds collected from three provinces of Northeast China from 2010 to 2012 were tested, and six ALV-J strains were isolated for the first time. Furthermore, the gp85 genes of the six strains were amplified, cloned, and sequenced. The results indicated that two different ALV-J strains coexisted in Chinese wild birds from 2010 to 2012. These results not only expand the epidemiological data available for ALV-J and provide necessary information for the further understanding of the evolution of ALV-J, but they also highlight the potential role of wild-bird migration in the spread of ALV-J. [ABSTRACT FROM AUTHOR]

Reverse genetic systems for efficient generation of very virulent infectious bursal disease virus (vvIBDV) are currently limited. In this study, we have developed a simple and efficient way to rescue vvIBDV using SPF chickens. The genome of a vvIBDV strain, HLJ0504, flanked by hammerhead and hepatitis delta ribozyme sequences, was cloned downstream of the cytomegalovirus enhancer and the chicken beta-actin promoter of the vector pCAGGS. After transfection of DF-1 cells, cell suspensions were injected into the bursa organ of three-week-old SPF chickens. Using this system, vvIBDV was recovered at high titers after one passage, and the rescued vvIBDV remained highly lethal to SPF chickens. This simple and efficient method to rescue vvIBDV will be a valuable tool for better understanding the molecular virulence determinants of vvIBDV. [ABSTRACT FROM AUTHOR]

Infectious bursal disease virus (IBDV) is a birnavirus that causes immunosuppressive disease in chickens. Segment B of IBDV encodes the RNA-dependent RNA polymerase VP1, which is involved in virulence. We sequenced and analyzed segment B from seven Chinese IBDV isolates, all belonging to very virulent IBDV (vvIBDV), and clustered into Branches II and III. Phylogenetic analysis suggested that segment B of the HLJ isolates in Branch II might have originated from an unidentified host, and HuB-1 might have originated in Europe. Eight aa (4V, 61I, 145T, 287A, 508K, 511S, 646S, and 687P) were conserved in Branches II and III, and may contain potential segment B virulence determinants. Five aa (146D, 242E, 390M, 562P, and 695R) were found only in Branch III, and may be origin characteristics. Moreover, 55T and 63A in the 5′-untranslated region (UTR), and 2786C in the 3′-UTR were conserved in vvIBDV and may function in UTR secondary structure. [ABSTRACT FROM AUTHOR]

Abstract  Using degenerate primers based on the conserved nucleotide binding site (NBS) and protein kinase domain (PKD), 100 resistance gene analogs (RGAs) were isolated from tobacco variety Nicotiana repanda. BLASTx search against the GenBank database revealed that 27 belong to the NBS class and 73 belong to the protein kinase (PK) class. Cluster analysis and multiple sequence alignment of the deduced protein sequences indicate that RGAs of the NBS class can be divided into two groups: toll/interleukin receptor (TIR) and non-TIR types. Both types possess 6 conserved motifs (P-loop, RNBS-A, Kinase-2, RNBS-B, RNBS-C, GLPL). Based on their sequence similarity, the tobacco RGAs of the PK class were assigned to 8 subclasses. We examined their expression after infection with either Tobacco mosaic virus (TMV) or the tobacco black shank pathogen (Phytophthora parasitica var. nicotianae). The expression levels of 4 RGAs of the PK class were significantly elevated by TMV and 1 RGA of the PK class and 3 RGAs of the NBS class were up-regulated by P. parasitica var. nicotianae. The expression of two RGAs of the PK class was induced by P. parasitica var. nicotianae. Infection by either TMV or P. parasitica var. nicotianae enhanced the expression of NtRGA2, a RGA of the PK class. The present study shows that RGAs are abundant in the tobacco genome and the identification of tobacco RGAs induced by pathogens should provide valuable information for cloning related resistance genes in tobacco. [ABSTRACT FROM AUTHOR]

Infectious bursal disease virus (IBDV), belonging to Avibirnavirus genus in the Birnaviridae family, consists of two segments of double-strand RNA. There are two distinct serotypes of IBDV, the pathogenic serotype I and the non-pathogenic serotype II. Comparison of the deduced amino acid sequences of a panel of VP5 genes retrieved from GenBank revealed a high identity among strains within the serotype I or serotype II group but a low identity between strains across two serotypes. In this study, we rescued two mosaic viruses, rGtGxVP5 and rGt2382VP5 by exchanging the VP5 gene of a cell culture-adapted serotype I Gt strain with its counterpart of the very virulent IBDV Gx strain, or a non-pathogenic 23/82 strain of the serotype II. In comparison to the parental strain rGt virus, the rGtGxVP5 showed the similar viral replication, cytotoxicity and the ability of inducing apoptosis; however, the other mosaic virus rGt2382VP5 had a lower titer and a reduced cytotoxicity. Although exchange of VP5 within serotype I group did not alter the viral replication and cytotoxicity of Gt strain, exchange of VP5 in the serotype I with that of a serotype II reduced the viral replication and cytotoxicity on chicken embryo fibroblast (CEF) cells. Therefore, the VP5 of serotype II may be one of the factors responsible for the distinct pathogenic features of two serotypes. [ABSTRACT FROM AUTHOR]

Plant disease resistance gene ( R gene) and defense response gene encode some conserved motifs. In the present work, a PCR strategy was used to clone resistance gene analogs (RGAs) and defense gene analogs (DGAs) from Sea-island cotton variety Hai7124 using oligonucleotide primers based on the nucleotide-binding site (NBS) and serine/threonine kinase (STK) in the R-gene and pathogenesis-related proteins of class 2 (PR2) of defense response gene. 79 NBS sequences, 21 STK sequences and 11 DGAs were cloned from disease-resistance cotton. Phylogenic analysis of 79 NBS-RGAs and NBS-RGAs nucleotide sequences of cotton already deposited in GenBank identified one new sub-cluster. The deduced amino acid sequences of NBS-RGAs and STK-RGAs were divided into two distinct groups respectively: Toll/Interleukin-1 receptor (TIR) group and non-TIR group, A group and B group. The expression of RGAs and DGAs having consecutive open reading frame (ORF) was also investigated and it was found that 6 NBS-RGAs and 1 STK-RGA were induced, and 1 DGA was up-regulated by infection of Verticillium dahliae strain VD8. 4 TIR-NBS-RGAs and 4 non-TIR-NBS-RGAs were arbitrarily used as probes for Southern-blotting. There existed 2–10 blotted bands. In addition, since three non-TIR-NBS-RGAs have the same hybridization pattern, we conjecture that these three RGAs form a cluster distribution in the genome. [ABSTRACT FROM AUTHOR]

The transmission of a recently identified Theileria species pathogenic for sheep and goats in northern China is described. Haemaphysalis qinghaiensis nymphs which had been collected from grass in epidemic areas were able to transmit this Theileria species to sheep. The pathogen was also transmitted to sheep and goats by three batches of adult ticks collected from grass, ticks collected when moving about on sheep and ticks which were found partially engorged on sheep or goats. [ABSTRACT FROM AUTHOR]

Numerical modeling of water movement in both unsaturated soils and saturated groundwater aquifers is important for water resource management simulations. The development of efficient numerical algorithms for coupling unsaturated and saturated flow has been a long-lasting challenge in hydrologic modeling, especially for regional-scale modeling. In this study, a new method coupling the Finite Element Method (FEM) and Finite Difference Method (FDM), FE-FDM, is developed to solve Richards equation for simulating unsaturated–saturated water flow. The FEM is adopted to discretize the governing equation in the horizontal direction, while the FDM is used in the vertical direction. This method combines the advantages of FEM in domain discretization, especially for complex computational domain, and the advantages of FDM in modeling simplicity and efficiency. The validity of the new method is demonstrated with three test cases that show that the FE-FDM solutions are accurate and are applicable for regional scale problems. In the test cases, the FE-FDM solutions are compared with experimental data and numerical results calculated with common software packages including FEFLOW and COMSOL. This study verified that the FE-FDM is applicable for simulating water flow in the unsaturated–saturated zone. [ABSTRACT FROM AUTHOR]

Avian gyrovirus 2 (AGV2) was the second member of the viral genus Cyclovirus to be discovered. This virus poses a significant potential threat to humans and poultry due to its global dissemination and infectiousness. We used three overlapping polymerase chain reactions (PCRs) to map the whole genome of AGV2. We then modelled the evolutionary history of these novel sequence data in the context of related sequences from GenBank. We analysed the viral protein characteristics of the different phylogenetic groups and explored differences in evolutionary trends between Chinese strains and strains from other countries. We obtained 17 avian-sourced AGV2 whole genomes from different regions of China from 2015 to 2016. Phylogenetic analyses of these Chinese AGV2 sequences and related sequences produced four distinct groups (A-D) with significant bootstrap values. We also built phylogenies using predicted viral protein sequences. We found a potential hypervariable region in VP1 at sites 288-314, and we identified the amino acid changes responsible for the distinct VP2 and VP3 groups. Three new motifs in the AGV2 5′-UTR direct repeat (DR) region were discovered and grouped. The novel characteristics and diverse research on the AGV2 genome provide a valuable framework for additional research. [ABSTRACT FROM AUTHOR]

Marek's disease virus (MDV) is a preferred vector in the construction of recombinant vaccines. However, bivalent vaccine based on MDV that confers full protection against both very virulent Marek's and infectious bursal disease virus (IBDV) infections in chickens has not been produced. Here we developed a system utilizing overlapping fosmid DNAs transfection that rescues an MDV type 1 (MDV1) vaccine strain. Using this system, we inserted the IBDV VP2 gene at MDV1 genome sites UL41, US10 and US2. The VP2 protein was stably expressed in the recombinant MDV-infected cells and self-assembled into IBDV subviral particles. Insertion of the VP2 gene did not affect the replication phenotype of MDV in cell cultures, nor did it increase the virulence of the MDV vaccine strain in chickens. After challenge with very virulent IBDV, r814US2VP2 conferred full protection, whereas r814UL41VP2 and r814US10VP2 provided partial or no protection. All the three recombinant vaccines provided full protection against very virulent MDV challenge in chickens. These results demonstrated that r814US2VP2 could be used as a promising bivalent vaccine against both Marek's and infectious bursal diseases in chickens. [ABSTRACT FROM AUTHOR]

Avian metapneumovirus (aMPV) and human metapneumovirus (hMPV) are members of the genus Metapneumovirus in the subfamily Pneumovirinae. Metapneumovirus fusion (F) protein mediates the fusion of host cells with the virus membrane for infection. Trypsin- and/or low pH-induced membrane fusion is a strain-dependent phenomenon for hMPV. Here, we demonstrated that three subtypes of aMPV (aMPV/A, aMPV/B, and aMPV/C) F proteins promoted cell-cell fusion in the absence of trypsin. Indeed, in the presence of trypsin, only aMPV/C F protein fusogenicity was enhanced. Mutagenesis of the amino acids at position 100 and/or 101, located at a putative cleavage region in aMPV F proteins, revealed that the trypsin-mediated fusogenicity of aMPV F proteins is regulated by the residues at positions 100 and 101. Moreover, we demonstrated that aMPV/A and aMPV/B F proteins mediated cell-cell fusion independent of low pH, whereas the aMPV/C F protein did not. Mutagenesis of the residue at position 294 in the aMPV/A, aMPV/B, and aMPV/C F proteins showed that 294G played a critical role in F protein-mediated fusion under low pH conditions. These findings on aMPV F protein-induced cell-cell fusion provide new insights into the molecular mechanisms underlying membrane fusion and pathogenesis of aMPV. [ABSTRACT FROM AUTHOR]

To investigate the effects of repeated sodium hypochlorite stress on the resistance of Salmonella enterica Serovar Enteritidis (S. Enteritidis) LWCC1051. LWCC1051 was exposed to Trypticase Soy Broth (TSB) containing sodium hypochlorite concentrations of 9 mmol/L, 10 mmol/L, and 11 mmol/L. After 13 repeated transfers and incubations, three sodium hypochlorite resisted LWCC1051 strains were obtained. The D-values and colony morphologies of these strains were assessed. Their survival rates at 60 °C, 65 °C, 70 °C, 75 °C, and − 20 °C were determined and lethality curves at these temperatures were fitted using the Weibull model. Additionally, the Minimal Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) for these strains in various chemicals, including malic acid, citric acid, ascorbic acid, acetic acid, lactic acid, hydrochloric acid, sodium hydroxide, potassium hydroxide, calcium chloride, sodium chloride, and potassium chloride were ascertained. Sodium hypochlorite concentrations of 9 mmol/L, 10 mmol/L, and 11 mmol/L in TSB induced sodium hypochlorite resistance in S. Enteritidis. D-value increased with the frequency of stress exposure. Higher concentrations of sodium hypochlorite resulted in greater D-values and noticeable differences in colony morphologies. The Weibull model accurately represented the temperature resistance curves of LWCC1051 at the specified temperatures. With increasing sodium hypochlorite stress, both high and low-temperature resistances of LWCC1051 improved. Furthermore, under acetic acid stress, the MIC and MBC values of LWCC1051 strains, post exposure to 9 mmol/L, 10 mmol/L, and 11 mmol/L sodium hypochlorite, doubled. Sodium hypochlorite stress enhances the cross-resistance of LWCC1051 to high temperature, low temperature, and acetic acid treatments. [ABSTRACT FROM AUTHOR]