Publications

Publications

The Pirbright Institute publication directory contains details of selected publications written by our researchers.

There were a total of 2609 results for your search.

Abstract

The rickettsial pathogen Ehrlichia ruminantium causes heartwater in ruminants and is transmitted by ticks of the genus Amblyomma. The map1 gene, encoding the major surface protein MAPI, is a member of a multigene family containing 16 paralogs. In order to investigate differential transcription of genes of the map] multigene family in vivo in unfed and feeding ticks, RNA was extracted from midguts and salivary glands of E. ruminantium-infected adult female Amblyomma variegatum ticks and analysed by RT-PCR using MAP1 paralog-specific primers. In unfed ticks, only transcripts from the map1-1 gene were observed in midguts and no transcripts were detected in salivary glands. In feeding ticks, map1-1 transcripts were more abundant in midguts whereas high levels of map1 transcripts were observed in salivary glands. Our results show that differential transcription of genes of the E. ruminantium map] cluster occurs in vivo in different tissues of infected ticks before and during transmission feeding, indicating that this multigene family may be involved in functions of biological relevance in different stages of the life cycle of E. ruminantium. (c) 2007 Elsevier B.V. All rights reserved.

Abstract

The DP71L protein of African swine fever virus (ASFV) shares sequence similarity with the herpes simplex virus ICP34.5 protein over a C-terminal domain. We showed that the catalytic subunit of protein phosphatase 1 (PP1) interacts specifically with the ASFV DP71L protein in a yeast two-hybrid screen. The chimeric full-length DP71L protein, from ASFV strain Badajoz 71 (BA71V), fused to glutathione S-transferase (DP71L-GST) was expressed in Escherichia coli and shown to bind specifically to the PP1-? catalytic subunit expressed as a histidine fusion protein (6×His-PP1?) in E. coli. The functional effects of this interaction were investigated by measuring the levels of PP1 and PP2A in ASFV-infected Vero cells. This showed that infection with wild-type ASFV strain BA71V activated PP1 between two- and threefold over that of mock-infected cells. This activation did not occur in cells infected with the BA71V isolate in which the DP71L gene had been deleted, suggesting that expression of DP71L leads to PP1 activation. In contrast, no effect was observed on the activity of PP2A following ASFV infection. We showed that infection of cells with wild-type BA71V virus resulted in decreased phosphorylation of the ? subunit of eukaryotic initiation factor 2 (eIF-2?). ICP34.5 recruits PP1 to dephosphorylate the ? subunit of eukaryotic translational initiation factor 2 (also known as eIF-2?); possibly the ASFV DP71L protein has a similar function.
Sammin D J, Paton D J, Parida S, Ferris N P, Hutchings G H, Reid S M, Shaw A E, Holmes C, Gibson D, Corteyn M, Knowles N J, Valarcher J F, Hamblin P A, Fleming L, Gwaze G, Sumption K J (2007)

Evaluation of laboratory tests for SAT serotypes of foot-and-mouth disease virus with specimens collected from convalescent cattle in Zimbabwe

Veterinary Record 160, 647-654

Abstract

During a field study in Zimbabwe, clinical specimens were collected from 403 cattle in six herds, in which the history of foot-and-mouth disease (FMD) vaccination and infection appeared to be known with some certainty. Five herds had reported outbreaks of disease one to five months previously but clinical FMD had not been observed in the sixth herd. A trivalent vaccine (South African Territories [SAT] types 1, 2 and 3) had been used in some of the herds at various times either before and/or after the recent outbreaks of FMD. The primary aim of this study was to evaluate the performance of serological tests for the detection of SAT-type FMD virus infection, particularly ELISAS for antibodies to non-structural proteins (NSPS) Of FMD Virus and solid phase competition ELISAS (SPCES) for serotypes SAT1 and SAT2. Secondary aims were to examine NSP seroconversion rates in cattle that had been exposed to infection and to compare virus detection rates by virus isolation and real-time reverse transcriptase-PCR (rtRT-PCR) tests on both oesophagopharyngeal fluids and nasopharyngeal brush swabbings. in addition, the hooves of sampled animals were examined for growth arrest lines as clinical evidence of FMD convalescence. Laboratory tests provided evidence of FMD virus infection in all six herds; SAT2 viruses were isolated from oesophagopharyngeal fluids collected from two herds in northern Zimbabwe, and SAT1 viruses were isolated from three herds in southern Zimbabwe. Optimised rtRT-PCR was more sensitive than virus isolation at detecting FMD virus persistence and when the results of the two methods were combined for oesophagopharyngeal fluids, between 12 and 35 per cent of the cattle sampled in the convalescent herds were deemed to be carriers. In contrast, nasopharyngeal swabs yielded only two virus-positive specimens. The overall seroprevalence in the five affected herds varied with the different NSPS from 56 per cent to 75 per cent, compared with 81 per cent and 91 per cent by homologous SPCE and virus neutralisation tests respectively. However, if serological test results were considered only for the cattle in which persistent infection with FMD virus had been demonstrated, 70 to 90 per cent scored seropositive in the different NSPS.

Abstract

Objective-To determine serum concentrations of the selected acute-phase proteins (APPs) haptoglobin, serum amyloid A (SAA), and C-reactive protein (CRP) in pigs experimentally inoculated with classical swine fever (CSF) and African swine fever (ASF) viruses. Animals-8 crossbred (Large White X Landrace) 10-week-old pigs. Procedures-Pigs were allocated to 2 groups (4 pigs/group). One group was inoculated with the CSF virus Alfort 187 strain, whereas the other group was inoculated with the ASF virus Spain 70 isolate. Blood samples were collected at various time points. At the end of the study, pigs were euthanized and a complete necropsy was performed, including histologic and immunohistochemical analyses. Results-Serum concentrations of APPS increased in pigs inoculated with CSF and ASF viruses, which suggested an acute-phase response in the course of both diseases. The most noticeable increase in concentration was recorded for SAA in both groups (up to a 300-fold increase for CSF virus and an approx 40-fold increase for ASF virus), followed by CRP and then haptoglobin, which each had only 3- to 4-fold increases. Conclusions and Clinical Relevance-Serum concentrations of APPs increased significantly in pigs inoculated with CSF and ASF viruses. However, differences were evident in serum concentrations of the proteins evaluated in this study.
Sanchez-Cordon P J, Gomez-Villamandos J C, Gutierrez J, Sierra M A, Pedrera M, Bautista M J (2007)

Atoxoplasma spp. infection in captive canaries (Serinus canaria)

Journal of Veterinary Medicine Series A-Physiology Pathology Clinical Medicine 54 (1), 23-26

Abstract

Clinical signs, histopathological and ultrastructural findings associated with Atoxoplasma spp. natural infection in captive canaries (Serinus canaria) are described. Intracytoplasmic Atoxoplasma-like protozoa were found in the liver and lung. In the liver, protozoa were found in hepatocytes and Kupffer's cells and were associated with granulomatous hepatitis and a marked bile duct hyperplasia. An usual finding was the presence of infected mononuclear cells adhered to the endothelium of the blood vessels in lung. The diagnosis was confirmed by ultrastructural examination of reprocessed paraffin-embedded tissues.

Abstract

Classical swine fever virus (CSFV) is a member of the genus Pestivirus in the family Flaviviridae. The Npro product of CSFV targets the host's innate immune response and can prevent the production of type I interferon (IFN). The mechanism by which CSFV orchestrates this inhibition was investigated and it is shown that, like the related pestivirus bovine viral diarrhea virus (BVDV), this involves the Npro protein targeting interferon regulatory factor-3 (IRF-3) for degradation by proteasomes and thus preventing IRF-3 from activating transcription from the IFN-? promoter. Like BVDV, the steady-state levels of IRF-3 mRNA are not reduced markedly by CSFV infection or Npro overexpression. Moreover, IFN-? stimulation of CSFV-infected cells induces the antiviral protein MxA, indicating that, as in BVDV-infected cells, the JAK/STAT pathway is not targeted for inhibition.
Sweeney T R, Moser A H, Shigenaga J K, Grunfeld C, Feingold K R (2006)

Decreased nuclear hormone receptor expression in the livers of mice in late pregnancy

American Journal of Physiology, Endocrinology and Metabolism 290 (6), E1313-E1320

Abstract

During the third trimester of pregnancy, there is an increase in serum triglyceride and cholesterol levels. The mechanisms accounting for these changes in lipid metabolism during pregnancy are unknown. We hypothesized that, during pregnancy, the expression of nuclear hormone receptors involved in regulating lipid metabolism would decrease. In 19-day pregnant mice, serum triglyceride and non-HDL cholesterol levels were significantly increased, whereas total cholesterol was slightly decreased, because of a decrease in the HDL fraction. Peroxisome proliferator-activated receptor (PPAR)α, PPARβ/δ, and PPARγ, liver X receptor (LXR)α and LXRβ, farnesoid X receptor (FXR), and retinoid X receptor (RXR)α, RXRβ, and RXRγ mRNA levels were significantly decreased in the livers of 19-day pregnant mice. Additionally, the expressions of thyroid receptor (TR)α, pregnane X receptor, sterol regulatory element-binding proteins (SREBP)-1a, SREBP-1c, SREBP-2, and liver receptor homolog 1 were also decreased, whereas the expression of TRβ, constitutive androstane receptor, and hepatic nuclear factor 4 showed no significant change. mRNA levels of the PPAR target genes carnitine-palmitoyl transferase 1α and acyl-CoA oxidase, the LXR target genes SREBP1c, ATP-binding cassettes G5 and G8, the FXR target gene SHP, and the TR target genes malic enzyme and Spot14 were all significantly decreased. Finally, the expressions of PPARγ coactivator (PGC)-1α and PGC-1β, known activators of a number of nuclear hormone receptors, were also significantly decreased. The decreases in expression of RXRs, PPARs, LXRs, FXR, TRs, SREBPs, and PGC-1s could contribute to the alterations in lipid metabolism during late pregnancy.

Ferris N P, King D P, Reid S M, Shaw A E, Hutchings G H (2006)

Comparisons of original laboratory results and retrospective analysis by real-time reverse transcriptase-PCR of virological samples collected from confirmed cases of foot-and-mouth in the UK in 2001

Veterinary Record 159 (12), 373-378

Abstract

There were 2030 designated cases of foot-and-mouth disease (FMD) during the course of the epidemic in the UK in 2001 (including four from Northern Ireland). Samples from 1720 of the infected premises (IPs) were received in the laboratory and examined for either the presence of FMD virus (virological samples from 1421 IPs) or both FMD virus and antibody (virological and serological samples from 255 IPs) or antibody alone (from 44 IPs). The time taken to issue final diagnostic results ranged from a few hours in cases in which positive results were obtained by ELISA on epithelia containing sufficient virus to be detected, to several days for samples containing small amounts of virus requiring amplification through cell culture, negative samples or samples tested for antibody. Two subsets of samples were analysed retrospectively by real-time reverse transcriptase-PCR (RT-PCR); first, epithelia that were negative by both ELISA and virus isolation (VI) in cell culture, and secondly, samples that were negative by ELISA on epithelial suspension but positive by VI. There was broad agreement between the RT-PCR and VI/ELISA combined, except that the RT-PCR procedure did not detect a group of related virus isolates from Wales. These viruses had evidently evolved during the epidemic and had a nucleotide substitution in the RT-PCR probe site, which prevented them from being detected by the routine diagnostic probe. No evidence of FMD virus, antibody or nucleic acid was found in approximately 23 per cent (390 of 1730) of IPs from which samples were received, suggesting that the incidence of FMD during the outbreak may have been over-reported.

Abstract

The vaccinia virus (VACV) protein A55 is a BTB/kelch protein with a broad-complex, tramtrack and bric-a-brac (BTB) domain in the N-terminal region and five kelch repeats in the C-terminal half. The BTB/kelch subgroup of the kelch superfamily of proteins has been associated with a wide variety of functions including regulation of the cytoskeleton. VACV contains three genes predicted to encode BTB/kelch proteins: A55R, F3L and C2L. The A55R gene product has been identified as an intracellular protein of 64 kDa that is expressed late in infection. A VACV strain lacking 93.6% of the A55R open reading frame (v Delta A55) was constructed and found to have an unaltered growth rate in vivo but a different plaque morphology and cytopathic effect, as well as reduced development of VACV-induced Ca2+-independent cell/extracellular matrix adhesion. In a murine intradermal model of VACV infection, a virus lacking the A55R gene induced larger lesions than wild-type and revertant control viruses.

Basto A P, Nix R J, Boinas F, Mendes S, Silva M J, Cartaxeiro C, Portugal R S, Leitao A, Dixon L K, Martins C (2006)

Kinetics of African swine fever virus infection in Ornithodoros erraticus ticks

Journal of General Virology 87 (7), 1863-1871

Abstract

The kinetics of African swine fever virus (ASFV) infection in Ornithodoros erraticus ticks were investigated in specimens collected in the field at different times following an outbreak of the disease in Portugal in 1999 and in ticks infected experimentally with a virus isolated from a tick collected during this outbreak. In ticks collected from the field, initial screening for ASFV was carried out by PCR, followed by attempts to isolate the virus in macrophage cultures. Considering total numbers of ticks tested independently of developmental stages, ASFV DNA was detected in 42.3, 26.4 and 22.4?% of specimens collected at weeks 0, 32 and 63 following the outbreak, respectively. Although virus was not isolated from most of these ticks, the proportion of isolations from large nymphs and adults increased between weeks 0 and 32 from 2 to 9?% and from 5 to 11.5?%, respectively. These results, together with the higher virus titres at week 32, suggest that virus replication occurred. In contrast, virus isolations from small nymphs decreased over this period, from 5 to 1.3?%. At week 63, infection rates decreased for all stages. Experimental infections showed the occurrence of virus replication within 4?weeks post-feeding and maintenance of high titres in almost 100?% of ticks until 20?weeks post-infection. At weeks 41 and 61, a drop in virus titres and infection rates was observed. Relevant to the understanding of African swine fever epidemiology, our results show that ASFV replicates and persists in O. erraticus, but a viral clearance occurs at later times in both natural and experimental infections.

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