Construction of a one-step multiplex real-time PCR assay for the detection of serogroups A, B, and E of Pasteurella multocida associated with bovine pasteurellosis

Bovine pasteurellosis, caused by serogroups A, B, and E of Pasteurella multocida (Pm), is mainly manifested as bovine respiratory disease (BRD) and hemorrhagic septicemia (HS). The disease has caused a great economic loss for the cattle industry globally. Therefore, identifying the Pm serogroups is critical for optimal diagnosis and subsequent clinical treatment and even epidemiological studies. In this study, a one-step multiplex real-time PCR assay was established. Three pairs of specific primers were prepared to detect the highly conserved genomic regions of serogroups A (HyaD), B (bcbD), and E (ecbJ) of Pm, respectively. The results depicted that the method had no cross-reaction with other bovine pathogens (Mannheimia hemolytica, Escherichia coli, Listeria monocytogenes, Staphylococcus aureus, Salmonella Dublin, Mycobacterium paratuberculosis, infectious bovine rhinotracheitis virus, and Mycoplasma bovis). The linear range (107 to 102 copies/μL) showed the R2 values for serogroups A, B, and E of Pm as 0.9975, 0.9964, and 0.996, respectively. The multiplex real-time PCR efficiency was 90.30%, 90.72%, and 90.57% for CartA, CartB, and CartE, respectively. The sensitivity result showed that the serogroups A, B, and E of Pm could be detected to be as low as 10 copies/μL. The repeatability result clarified that an intra-assay and an inter-assay coefficient of variation of serogroups A, B, and E of Pm was < 2%. For the clinical samples, the detection rate was higher than the OIE-recommended ordinary PCR. Overall, the established one-step multiplex real-time PCR assay may be a valuable tool for the rapid and early detection of the serogroups A, B, and E of Pm with high specificity and sensitivity

Increased Neutralizing Antibody Production and Interferon-γ Secretion in Response to Porcine Reproductive and Respiratory Syndrome Virus Immunization in Genetically Modified Pigs

T cell-mediated immunity plays a prominent role in combating pathogens infection. Both the engagement of the T cell receptor with the peptide-bound major histocompatibility complex and a costimulatory signal are needed for the complete activation of the T cell. To determine whether host immune responses to vaccination could be improved by enhancing CD28-mediated costimulation and verify whether the boosted immune responses could protect the host against viral challenge, we produced a transgenic pig line expressing an extra copy of the CD28 gene controlled by its own promoter at the Rosa26 locus. As expected, in response to porcine reproductive and respiratory syndrome virus (PRRSV) strain vaccination, CD4+ T cells was remarkably increased in CD28 transgenic pigs and a similar response in CD8+ T cells was elicited after challenge. Importantly, because of increased T cell frequencies, the virus-neutralizing antibody against JXA-1 (a highly pathogenic Chinese PRRSV strain), as well as interferon-γ secretion, were enhanced in transgenic pigs. These findings in our translational study provide a novel concept for farm animal breeding in disease resistance, in which we may use the transgenic technology to force overexpression of confirmed immunity-promoting molecules like CD28 and produce an animal with enhanced immune responses to vaccination and broad-spectrum resistance to infectious diseases

A fully soft generator with embedded conditioning circuitry

This letter presents a fully soft dielectric elastomer generator (DEG) based on a capacitive kinetic-energy-harvesting mechanism. First, using the principle of a passive charge pump, a self-cycling conditioning circuit topology is proposed. Through the electrical reciprocity of a cyclically deforming DEG and another capacitor in series with it, the generated charge can be continuously supplied to the load, via a bilateral conditioning bridge. The antagonistic dual-DEG scheme not only produces a larger potential to drive more charge in the flow but also provides a basic solution to soften the whole device. A further measure is to replace the bridge diodes with special dielectric elastic switches (DESs), which can be embedded into the DEG and synchronously deformed with the latter to control the on/off state of the circuit branches. The intrinsic physical mechanism and characteristics of the change in the resistance of the DES as a function of stretch and electric fields are investigated. We tested and compared the diode-bridge and DES-bridge schemes under different electrical loads and tensile strokes. The results indicate that under certain conditions, the DES-bridge circuit can achieve comparable performance with that of a conventional scheme, which suggests that a fully soft DEG system is possible. We experimentally evaluated and discussed its reliability in practice.Published versio

Capacitive energy harvesting using soft dielectric elastomers: Design, testing and impedance matching optimization

Energy harvesting based on dielectric elastomeric materials, in nature, embodies a capacitive kinetic energy conversion mechanism where the soft DE generator (DEG) interactively cooperates with conditioning circuits. Based on the principle of passive charge pump, this paper proposes a design concept for a self-cycling energy harvesting circuit driven by DEG cyclic deformation, with its essential behavioral mode laid on the electrical reciprocity between the DEG intrinsic capacitor and another capacitor connected in series. By detailed simulation experiments, the working process and dynamic characteristics of the proposed system, as well as the influence of circuital, operating, and load parameters on system performance are quantitatively investigated, with intensive discussions for the time delay behaviors caused by changes of load resistance, along with the different impacts of its value regions. Then, the theoretical analyses are effectively validated by experimental tests for a specially-designed annular DEG prototype. Under the global optimization framework based on impedance matching, this paper presents some guidelines for circuit design, e.g., the selection criteria of the capacitance and load resistance. In addition, the potential of this emerging technology is also demonstrated by experiments

Isolation, Identification, and Characterization of a New Highly Pathogenic Field Isolate of Mycobacterium avium spp. avium

Avian tuberculosis is a chronic, contagious zoonotic disease affecting birds, mammals, and humans. The disease is most often caused by Mycobacterium avium spp. avium (MAA). Strain resources are important for research on avian tuberculosis and vaccine development. However, there has been little reported about the newly identified MAA strain in recent years in China. In this study, a new strain was isolated from a fowl with symptoms of avian tuberculosis by bacterial culture. The isolated strain was identified to be MAA by culture, staining, and biochemical and genetic analysis, except for different colony morphology. The isolated strain was Ziehl-Zeelsen staining positive, resistant to p-nitrobenzoic acid, and negative for niacin production, Tween-80 hydrolysis, heat stable catalase and nitrate production. The strain had the DnaJ gene, IS1245, and IS901, as well. Serum agglutination indicated that the MAA strain was of serotype 1. The MAA strain showed strong virulence via mortality in rabbits and chickens. The prepared tuberculin of the MAA strain had similar potency compared to the MAA reference strain and standard tuberculin via a tuberculin skin test. Our studies suggested that this MAA strain tends to be a novel subtype, which might enrich the strain resource of avian tuberculosis