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C J Bostock

Publications and source records attributed to C J Bostock.

At least 19 recordsLinked to original sources
PubMed1997

Transmissions to mice indicate that 'new variant' CJD is caused by the BSE agent.

There are many strains of the agents that cause transmissible spongiform encephalopathies (TSEs) or 'prion' diseases. These strains are distinguishable by their disease characteristics in experimentally infected animals, in particular the incubation periods and neuropathology they produce in panels of inbred mouse strains. We have shown that the strain of agent from cattle affected by bovine spongiform encephalopathy (BSE) produces a characteristic pattern of disease in mice that is retained after experimental passage through a variety of intermediate species. This BSE 'signature' has also been identified in transmissions to mice of TSEs of domestic cats and two exotic species of ruminant, providing the first direct evidence for the accidental spread of a TSE between species. Twenty cases of a clinically and pathologically atypical form of Creutzfeldt-Jakob disease (CJD), referred to as 'new variant' CJD (vCJD), have been recognized in unusually young people in the United Kingdom, and a further case has been reported in France. This has raised serious concerns that BSE may have spread to humans, putatively by dietary exposure. Here we report the interim results of transmissions of sporadic CJD and vCJD to mice. Our data provide strong evidence that the same agent strain is involved in both BSE and vCJD.

Animals↗
PubMed1997

Trial of a capripoxvirus-rinderpest recombinant vaccine in African cattle.

Cattle were vaccinated with differing doses of an equal mixture of capripox-rinderpest recombinant viruses expressing either the fusion protein (F) or the haemagglutinin protein (H) of rinderpest virus. Animals vaccinated with 2 x 10(4) p.f.u. or greater of the combined viruses were completely protected against challenge, 1 month later, with both virulent rinderpest and lumpy skin disease viruses. Vaccination with any of the doses did not induce any adverse clinical response in the animals or transmission of the vaccine virus between animals. All cattle challenged 6 or 12 months after vaccination with 2 x 10(5) p.f.u. of the mixture of recombinant viruses were protected from severe rinderpest disease. Ten out of 18 were completely protected while the remaining 8 developed mild clinical signs of rinderpest. Cattle vaccinated with the recombinant vaccines after prior infection with the parental capripox virus showed more marked clinical signs of rinderpest after challenge with virulent rinderpest, but 9 out of 10 recovered, compared with 80% mortality in the unvaccinated controls.

Animals↗
PubMed1993

Behaviour of plasmid containing C4A2 repeats in S. cerevisiae and S. pombe.

Plasmid, which combined the complete genome of BPV-I, yeast ARS, LEU yeast selectable marker gene, the NEO selectable marker gene and inverted (C4A2)n telomeric repeat gene sequences cloned originally from Tetrahymena thermophila, was constructed. It was introduced in either circular or linear form to Saccharomyces cerevisiae or Schizosaccharomyces pombe. Although both yeasts could replicate the plasmid extrachromosomally, irrespective of whether it was introduced as a circular or linear structure, the yeasts did differ in their ability to resolve a circular plasmid carrying the telomeric sequences into linear forms. S. cerevisiae was found to resolve the circular form of pCA/LEU/ARS to the linear structure, whereas circular pCA/LEU/ARS remained circular in S. pombe. On the other hand, pCA/LEU/ARS which had been previously linearised at the telomeric sequence was maintained as a linear structure in S. pombe and S. cerevisiae.

Animals↗
PubMed1992

Molecular and serological studies on the recent seal virus epizootics in Europe and Siberia.

The virus epizootics which occurred in seals in both Europe and Siberia during 1987/1988 were caused by two different morbilliviruses, referred to as phocid distemper virus (PDV) 1 and 2, respectively. Molecular and serological studies have shown that the European virus is quite distinct from canine distemper virus (CDV), its closest relative in the morbillivirus group. Analysis of tissues obtained from infected seals from a wide geographical distribution over Northern Europe showed that the infectious agent (PDV 1) was identical in all cases. Nucleotide sequence analysis of one of the virus genes suggested that this virus has evolved away from CDV over a long time period and is most probably an enzootic virus of marine mammals. In contrast, the virus (PDV 2) which caused the deaths of many Siberian seals was indistinguishable, both serologically and at the molecular level, from CDV and must have originated from a land source.

Animals↗
PubMed1992

Molecular biology of scrapie-like agents.

A detailed account is given of the nature of the causal agent of scrapie and other transmissible spongiform encephalopathies, with reference to proteinase-resistant protein and its gene, subviral particles and the prion hypothesis.

Alleles↗
PubMed1990

Construction of a neo fusion gene for expression in both prokaryotic and eukaryotic cells.

A high-copy-number plasmid, pLink, was constructed to allow the direct selection in Escherichia coli of a neo fusion gene capable of conferring Geneticin (G418) resistance on mouse L cells. pLink was derived from pdMmtneo by insertion of a KpnI linker within the 5'-coding region of the neo gene. This created a minus-one frameshift mutation resulting in a translational termination within the N-terminal region of the protein. The Neo activity was restored by insertion into the modified neo gene of a piece of coding sequence derived from human HPRT cDNA. The resulting plasmid, pAH, was microinjected into mouse A9 cells and shown to confer resistance to G418.

Animals↗
PubMed1990

Development of the polymerase chain reaction for the detection of bluetongue virus in tissue samples.

Total genomic dsRNA, extracted from purified core particles of bluetongue virus serotype 1 from South Africa (BTV1SA), was used as template to optimise a polymerase chain reaction (PCR) for the detection of bluetongue virus RNA. Pairs of oligonucleotides complementary to the 3' termini of eight of the ten genome segments were tested. Those representing the 5' termini of genome segment 7 gave the best amplification results producing a single DNA band with the same mobility during agarose gel electrophoresis as genome segment 7. It was confirmed by cloning and sequence analysis, that this PCR-amplified DNA contained both terminal regions of genome segment 7 and therefore represented full length cDNA. Using these segment 7 oligonucleotides it was not only possible to detect routinely as few as 6 molecules of segment 7 dsRNA per sample, but also to detect purified dsRNAs from isolates of other BTV serotypes (1 Australia (AUS), 2, 3, 4, 10, 16 and 20). However, with the exception of Tilligery virus, isolates from other Orbivirus serogroups tested all gave negative results (African horse sickness, epizootic haemorrhagic disease, Palyam, Warrego and Eubenangee). The PCR was also used to analyse red blood cells (RBC) and buffy coat samples from cattle infected with BTV4. Positive results were obtained from samples taken 7 days post-infection (p.i.) (containing 1.6 x 10(3) TCID50 of virus/ml of whole blood) and from the RBC sample only, taken 14 days p.i. (16 TCID50/ml). However, at 28 days p.i. (less than 1.6 TCID50/ml) BTV RNA was not detected using the PCR in either sample.

Animals↗
PubMed1990

Viruses as vectors.

Traditional vaccines against diseases caused by viruses are based on live attenuated viruses or killed virus preparations. Through the application of molecular biology it is now possible to consider several new approaches to making vaccines, which may combine increased efficacy with greater safety. One of these approaches is to manipulate genetically a virus so that it carries and expresses a foreign gene (or part of a gene) which codes for a protective antigen for another disease. Adeno-, polio- and herpesviruses have been engineered to act as vectors in this way but vaccinia virus remains the main candidate for a recombinant virus vector for vaccine use. The broad host-range of vaccinia virus has made it an effective vector for the analysis of expression of "foreign" antigens as well as a tool for the dissection of the host animal's immune system. For practical purposes in veterinary vaccines, recombinant viruses based on other poxviruses, with more restricted host-ranges, may have certain advantages. Work on the development of recombinant avipoxviruses and capripoxviruses as prototype vaccines for use in poultry and ruminants, respectively, is discussed and illustrated.

Animals↗
PubMed1990

Characterisation of the European seal morbillivirus.

The ELISA test originally developed for the detection of serum antibodies to rinderpest virus has been shown to detect cross-reacting antibodies in sera of diseased common and grey seals. Analysis of sera collected from various seal populations is in progress to establish the correlation between different morbillivirus neutralisation tests, ELISA tests and the disease status of the animals. RNA purified from post-mortem tissues removed from diseased seals has been analysed by hybridisation with cloned cDNAs made to various genes of canine distemper, peste des petits ruminants, rinderpest and measles viruses. This study has confirmed the presence of RNA sequences characteristic of a morbillivirus, but shown that the virus is not identical with any known morbillivirus. Work is in progress to determine the nucleotide sequences of clones carrying inserts homologous to morbillivirus genes isolated from cDNA made on a template of infected seal tissue RNA.

Animals↗
PubMed1990

Detection of phocine distemper virus using the polymerase chain reaction.

During the fatal seal epizootics in the North and Baltic Seas in summer 1988 a virus was isolated which was shown to be the causal agent. It was subsequently classified as morbillivirus by neutralization assays, reaction with monoclonal antibodies and nucleic acid hybridization studies. The virus (tentatively called Phocine Distemper Virus, PDV) is difficult to grow in culture making rapid diagnosis difficult. We have used the Polymerase Chain Reaction (PCR) as an alternative and fast method to detect the presence of virus-specific nucleic acid and we describe here the amplification of cell culture derived PDV RNA in a "one-tube" reaction using heterologous (Rinderpest Virus cDNA derived) F gene primers. The resulting 370 bp DNA fragment was shown to be morbillivirus derived by Southern blot hybridization using cloned RPV F gene as probe.

Animals↗
PubMed1988

Parameters of field inversion gel electrophoresis for the analysis of pox virus genomes.

The effects of variation in the lengths of forward and reverse pulses, voltage gradient, gel concentration and gel temperature on the mobility of DNA molecules in agarose gels during field inversion gel electrophoresis (FIGE) have been determined. A curve, which best fits the empirical data, is presented and allows the choice of pulse conditions and voltage gradient most suitable for the resolution of molecules of chosen size. The use of FIGE in the analysis and direct mapping of large virus genomes is illustrated using vaccinia virus DNA.

DNA, Viral↗
PubMed1988

Studies on the infectivity of foot-and-mouth disease virus RNA using microinjection.

Foot-and-mouth disease virus (FMDV) RNA, isolated as virion RNA from purified virus particles or as total RNA from infected cells, has been microinjected into nuclei and cytoplasms of BHK cells. When injected directly into the nucleus FMDV RNA was not infectious, whereas cytoplasmic injection resulted in a high proportion of productive infections. Infectivity microinjection assays on dilution series of various FMDV RNAs showed that both single-stranded positive sense 35S RNA and double-stranded replicative form (Rf) RNA have an infectivity close to 1 p.f.u. per molecule, although only a minor fraction of BHK cells appeared able to support plaque formation following microinjection of Rf FMDV RNA. The infectivity of Rf FMDV RNA was not sensitive to inhibition by actinomycin D. The results are discussed in relation to the high virus particle to p.f.u. ratios observed for FMDV.

Animals↗
PubMed1987

Different subfamilies of alphoid repetitive DNA are present on the human and chimpanzee homologous chromosomes 21 and 22.

The alphoid repeat DNA on chimpanzee chromosome 22 was compared with alphoid repeat DNA on its human homologue, chromosome 21. Hybridization of different alphoid probes under various conditions of stringency show that the alphoid repeats of chimpanzee chromosome 22 are not closely related to those of human chromosome 21. Sequence analysis of cloned dimer and tetramer EcoRI fragments from chimpanzee chromosome 22 confirm the low overall level of homology, but reveal the presence of several nucleotide changes which are exclusive to the chromosome 21 subfamily of human alphoid DNA. Southern blot analysis of alphoid repeat DNA on the chimpanzee X chromosome suggests this subfamily has been strongly conserved during and since the separation of chimpanzee and man although the two subfamilies can be distinguished on the basis of Taq I restriction fragments.

Animals↗