Molecular characterization of porcine reproductive and respiratory syndrome virus

Porcine reproductive and respiratory syndrome (PRRS), an economically important swine disease, is caused by a previously unrecognized virus referred to as porcine reproductive and respiratory syndrome virus (PRRSV). In this study, PRRSV was isolated and characterized in a continuous cell line designated as ATCC CRL11171. PRRSV was found to be an enveloped, nonhemagglutinating, and spherical RNA virus ranging from 50 to 70 nm in diameter. The genome of PRRSV is a positive-stranded, polyadenylated RNA of approximately 15 kb. Six open reading frames (ORFs) were identified in the 3\u27-terminal viral genome. ORFs 2 to 4 are predicted to encode viral membrane-associated proteins, and ORFs 5 to 7 likely encode envelope, matrix and nucleocapsid proteins, respectively. A nested set of six or seven subgenomic mRNAs (sg mRNAs) was found in CRL11171 cells infected with different PRRSV isolates. These sg mRNAs were not packaged into virions. The leader-mRNA junction sequences of sg mRNAs 3, 4 and 4-1 contain a common six nucleotide sequence motif, T(G)TA(G/C)ACC. Extensive sequence variation exists between U.S. and European PRRSV isolates. The amino acid sequence identity in ORFs 2 to 7 between U. S. isolate VR2385 and European isolate LV is only about 60%. Sequence variation was also found among North American isolates. The amino acid sequence identity in ORFs 2 to 4 between seven North American isolates was 91-99%, 86-98%, 92-99% and 88-99%, respectively. However, ORFs 6 and 7 of all North American isolates were highly conserved. A low virulence U.S. isolate had highest sequence variation in ORFs 2 to 4 compared with that of other U.S. isolates. Phylogenetic analyses showed that PRRSV was closely related to lactate dehydrogenase-elevating virus (LDV) and distantly related to equine arteritis virus (EAV). The U.S. and the European isolates of PRRSV represent two different genotypes, and, within the major U.S. genotype, there are at least three minor genotypes. The results from this study suggest that PRRSV belongs to the newly proposed Arteriviridae family, which includes LDV, EAV and simian hemorrhagic fever virus

Assessment of the cross-protective capability of recombinant capsid proteins derived from pig, rat, and avian hepatitis E viruses (HEV) against challenge with a genotype 3 HEV in pigs

Hepatitis E virus (HEV), the causative agent of hepatitis E, is primarily transmitted via the fecal-oral route through contaminated water supplies, although many sporadic cases of hepatitis E are transmitted zoonotically via direct contact with infected animals or consumption of contaminated animal meats. Genotypes 3 and 4 HEV are zoonotic and infect humans and other animal species, whereas genotypes 1 and 2 HEV are restricted to humans. There exists a single serotype of HEV, although the cross-protective ability among the animal HEV strains is unknown. Thus, in this study we expressed and characterized N-terminal truncated ORF2 capsid antigens derived from swine, rat, and avian HEV strains and evaluated their cross-protective ability in a pig challenge model. Thirty, specific-pathogen-free, pigs were divided into 5 groups of 6 pigs each, and each group of pigs were vaccinated with 200 µg of swine HEV, rat HEV, or avian HEV ORF2 antigen or PBS buffer (2 groups) as positive and negative control groups. After a booster dose immunization at 2 weeks post-vaccination, the vaccinated animals all seroconverted to IgG anti-HEV. At 4 weeks post-vaccination, the animals were intravenously challenged with a genotype 3 mammalian HEV, and necropsied at 4 weeks post-challenge. Viremia, fecal virus shedding, and liver histological lesions were compared to assess the protective and cross-protective abilities of these antigens against HEV challenge in pigs. The results indicated that pigs vaccinated with truncated recombinant capsid antigens derived from three animal strains of HEV induced a strong IgG anti-HEV response in vaccinated pigs, but these antigens confer only partial cross-protection against a genotype 3 mammalian HEV. The results have important implications for the efficacy of current vaccines and for future vaccine development, especially against the novel zoonotic animal strains of HEV

Rescue of a genotype 4 human hepatitis E virus from cloned cDNA and characterization of intergenotypic chimeric viruses in cultured human liver cells and in pigs

Hepatitis E virus (HEV) is an important but extremely understudied human pathogen. Genotypes 1 and 2 are restricted to humans, whereas genotypes 3 and 4 are zoonotic, infecting both humans and pigs. This report describes, for the first time, the successful rescue of infectious HEV in vitro and in vivo from cloned cDNA of a genotype 4 human HEV (strain TW6196E). The complete genomic sequence of the TW6196E virus was determined and a full-length cDNA clone (pHEV-4TW) was assembled. Capped RNA transcripts from the pHEV-4TW clone were replication competent in Huh7 cells and infectious in HepG2/C3A cells. Pigs inoculated intrahepatically with capped RNA transcripts from pHEV-4TW developed an active infection, as evidenced by faecal virus shedding and seroconversion, indicating the successful rescue of infectious genotype 4 HEV and cross-species infection of pigs by a genotype 4 human HEV. To demonstrate the utility of the genotype 4 HEV infectious clone and to evaluate the potential viral determinant(s) for species tropism, four intergenotypic chimeric clones were constructed by swapping various genomic regions between genotypes 1 and 4, and genotypes 1 and 3. All four chimeric clones were replication competent in Huh7 cells, but only the two chimeras with sequences swapped between genotypes 1 and 4 human HEVs produced viruses capable of infecting HepG2/C3A cells. None of the four chimeras was able to establish a robust infection in pigs. The availability of a genotype 4 HEV infectious clone affords an opportunity to delineate the molecular mechanisms of HEV cross-species infection in the future

Traffic Scheduling Strategy of Power Communication Network Based on SDN

Due to the complicated structure, power communication network is difficult to guarantee the quality of service (QoS) of power services. A two-level scheduling algorithm based on software defined network (SDN) is proposed in this paper. Firstly, the priority-based scheduling method is used to meet the latency-sensitive of power service. Then, in order to alleviate congestion, queue bandwidth is adjusted according to network state information, which can be collected by the centralized control of SDN. Finally, the Mininet and Ryu controller are made use of building simulation environment. The test results show that the algorithm proposed in this paper reduce delay and packet loss rate significantly, which achieves QoS

Tetrahedron genuine entanglement measure of four-qubit systems

Quantifying genuine entanglement is a key task in quantum information theory. We study the quantification of genuine multipartite entanglement for four-qubit systems. Based on the concurrence of nine different classes of four-qubit states, with each class being closed under stochastic local operation and classical communication, we construct a concurrence tetrahedron. Proper genuine four-qubit entanglement measure is presented by using the volume of the concurrence tetrahedron. For non genuine entangled pure states, the four-qubit entanglement measure classifies the bi-separable entanglement. We show that the concurrence tetrahedron based measure of genuine four-qubit entanglement is not equivalent to the genuine four-partite entanglement concurrence. We illustrate the advantages of the concurrence tetrahedron by detailed examples.Comment: 23 pages, 4 figure

Research on the compression algorithm of the infrared thermal image sequence based on differential evolution and double exponential decay model.

This paper has proposed a new thermal wave image sequence compression algorithm by combining double exponential decay fitting model and differential evolution algorithm. This study benchmarked fitting compression results and precision of the proposed method was benchmarked to that of the traditional methods via experiment; it investigated the fitting compression performance under the long time series and improved model and validated the algorithm by practical thermal image sequence compression and reconstruction. The results show that the proposed algorithm is a fast and highly precise infrared image data processing method

Diaqua­[5,5′-dicarb­oxy-2,2′-(propane-1,3-di­yl)bis­(1H-imidazole-4-carboxyl­ato)]manganese(II)

The complex mol­ecule of the title compound, [Mn(C13H10N4O8)(H2O)2] or [Mn(H4pbidc)(H2O)2] (H6pbidc = 2,2′-(propane-1,3-di­yl)bis­(1H-imidazole-4,5-dicarb­oxy­lic acid), has 2 symmetry with the twofold rotation axis running through the Mn2+ cation and the central C atom of the propanediyl unit. The cation is six-coordinated by two N atoms and two O atoms from one H4pbidc2− anion and two water O atoms in a considerably distorted octa­hedral coordination. In the crystal, adjacent mol­ecules are linked through O—H⋯O and N—H⋯O hydrogen bonds into a three-dimensional network

A live-attenuated and an inactivated chimeric porcine circovirus (PCV)1-2 vaccine are both effective at inducing a humoral immune response and reducing PCV2 viremia and intrauterine infection in female swine of breeding age

The objective of this pilot study was to determine the efficacy of inactivated (1 or 2 dose) and live-attenuated chimeric porcine circovirus (PCV)1-2 vaccines in sows using the PCV2-spiked semen model. Thirty-five sows were randomly divided into 6 groups: negative and positive controls, 1 dose inactivated PCV1-2 vaccine challenged (1-VAC-PCV2), 2 dose inactivated PCV1-2 vaccine challenged (2-VAC-PCV2), 1 dose live-attenuated PCV1-2 vaccine unchallenged (1-LIVE-VAC), and 1 dose live-attenuated PCV1-2 vaccine challenged (1-LIVE-VAC-PCV2). The inactivated PCV1-2 vaccine induced higher levels of PCV2-specific antibodies in dams. All vaccination strategies provided good protection against PCV2 viremia in dams, whereas the majority of the unvaccinated sows were viremic. Four of the 35 dams became pregnant: a negative control, a positive control, a 2-VAC-PCV2 sow, and a 1-LIVE-VAC-PCV2 sow. The PCV2 DNA was detected in 100%, 67%, and 29% of the fetuses obtained from the positive control, inactivated vaccinated, or live-attenuated vaccinated dams, respectively. The PCV2 antigen in hearts was only detectable in the positive control litter (23% of the fetuses). The PCV1-2 DNA was detected in 29% of the fetuses in the litter from the 1-LIVE-VAC-PCV2 dam. Under the conditions of this pilot study, both vaccines protected against PCV2 viremia in breeding age animals; however, vertical transmission was not prevented