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B A Allsopp

Publications and source records attributed to B A Allsopp.

51 records · Page 3Linked to original sources
PubMed1993

Discrimination between six species of Theileria using oligonucleotide probes which detect small subunit ribosomal RNA sequences.

The complete small subunit ribosomal RNA (srRNA) gene of Theileria parva was cloned and sequenced. Two primers were designed which permitted the specific amplification of part of the Theileria srRNA gene from Theileria-infected cell line samples which were predominantly (> 95%) bovine DNA. The sequence of the central (variable) region of the srRNA genes of T. annulata, T. taurotragi, T. mutants and two unidentified parasites referred to as Theileria sp. (buffalo) and Theileria sp. (Marula) were obtained. An alignment of the sequences was generated from which 6 oligonucleotide probes, corresponding to species-specific regions, were designed. These probes were demonstrated to provide unequivocal identification of each of the 6 species either by direct detection of parasite srRNA or by hybridization to amplified parasite srRNA genes. The probes were not able to distinguish buffalo-derived T. parva, the causal agent of Corridor disease, from cattle-derived T. parva, the causal agent of East Coast fever.

Animals↗
PubMed1993

Detection of polymorphisms among Theileria parva stocks using repetitive, telomeric and ribosomal DNA probes and anti-schizont monoclonal antibodies.

A total of 21 Theileria parva stocks from 6 countries were characterized using T. parva repetitive and ribosomal DNA probes, a Plasmodium berghei telomeric oligonucleotide and a panel of anti-schizont monoclonal antibodies (MAbs). Hybridization of the repetitive DNA probe to Southern blots of EcoRI-digested T. parva DNA revealed 20 different restriction fragment patterns among DNA samples isolated from infections initiated using 16 parasite stocks. The panel of anti-schizont MAbs defined 8 different profiles among schizont-infected lymphoblastoid cell-cultures infected with the same 16 T. parva stocks. Many stocks, which were differentiated by the repetitive DNA probe, could not be distinguished using the anti-schizont MAbs. A cloned T. parva small subunit ribosomal RNA (SSUrRNA) gene probe separated 17 T. parva stocks into 2 groups, exhibiting either 1 or 2 restriction fragments, when hybridized to EcoRI-digested T. parva DNA. When hybridized to PvuII-digested DNA from 8 T. parva stocks, the ribosomal probe identified 4 groups with similar restriction fragment patterns. A synthetic oligonucleotide derived from a P. berghei telomeric sequence hybridized to 7 or 8 size-polymorphic restriction fragments in the EcoRI-digested DNA of most T. parva stocks. The telomeric and ribosomal probes defined the same 4 groups among 8 T. parva stocks as assessed by similarities in restriction fragment patterns. Based on the comparison of repetitive DNA sequences from the T. parva Uganda and Muguga stocks, a synthetic oligonucleotide was developed which distinguished the DNA of the T. parva Uganda stock from that of 4 other T. parva stocks on a positive/negative basis.

Animals↗
PubMed1992

Detection of a carrier state in Theileria parva-infected cattle by the polymerase chain reaction.

Two sets of oligonucleotide primers, one derived from a repetitive sequence and the other from the gene encoding a 67 kDa sporozoite antigen of Theileria parva, were used to amplify parasite DNA from the blood of T. parva-infected carrier cattle using the polymerase chain reaction (PCR). PCR amplification products were obtained from 15 carrier cattle infected with one of 4 different T. parva stocks. Successful amplifications were performed using DNA from 2 cattle infected with T. p. parva Pemba Mnarani, 10 cattle infected with T. p. parva Marikebuni, 2 cattle infected with T. p. bovis Boleni and 1 animal infected with T. p. lawrencei 7014. No amplification products were obtained from any of 7 cattle which had been infected with the T. p. parva Muguga stock. A synthetic oligonucleotide, which hybridized specifically to T. p. parva Marikebuni DNA among 6 T. parva stocks tested, was designed using sequence data from within the region of the T. parva genome amplified by the repetitive sequence primers. The oligonucleotide was used to probe PCR products and to increase the sensitivity and specificity of carrier animal detection. Southern blot analysis using a T. parva repetitive sequence probe demonstrated the existence of restriction fragment length polymorphisms between parasites isolated from T. p. parva Marikebuni-infected carrier cattle. The use of the PCR and other methods of carrier animal detection are discussed.

Amino Acid Sequence↗
PubMed1991

An unusual repetitive gene family in Theileria parva which is stage-specifically transcribed.

Tpr1 is a repetitive DNA element from Theileria parva which has previously been shown to be of value in strain characterisation. Further characterisation, described here, has shown that Tpr1 is present in long tandem arrays. The sequence of 8.1 kb from one end of an array has been determined. The sequence showed that Tpr1 is a 1.44-kb element which contains an ORF extending from its 5' end to the 3' end. The sequenced region contains 4 large ORFs; 2 of these consisted only of Tpr1 whilst the third consisted of Tpr1 and a 0.55-kb element (Tpr2) located 5' of Tpr1. The largest ORF consisted of Tpr1 plus Tpr2 as well as an additional 420-bp element (Tpr3) 5' of Tpr2, thus a continuous ORF arranged 5'-Tpr3-Tpr2-Tpr1-3' was formed. This ORF potentially encodes a 795 amino acid polypeptide commencing at an ATG close to the 5' end. In contrast the first in frame ATGs in the other 3 ORFs are at least 417 bp from the 5' end. Southern analysis confirmed that the sequenced region was typical of the rest of the Tpr array(s). Transcripts containing both Tpr3 and Tpr1 were detected in the piroplasm but not the schizont stages of the life cycle.

Amino Acid Sequence↗
PubMed1988

Theileria parva: genomic DNA studies reveal intra-specific sequence diversity.

Theileria parva parva piroplasm DNA was purified from 11 different infections of cattle with 6 different East African isolates of the parasite. Total DNA was also prepared from bovine lymphoblastoid cells infected with schizonts of one of the isolates. Two of the infections were with cloned parasites. The DNA was of high molecular weight and free from protein and RNA, but some of the samples contained a proportion of bovine DNA. The 6 samples least contaminated with bovine DNA had a mean 'melting' temperature (Tm) of 84 degrees C and a mean GC content of 31.3%. Reassociation kinetics gave an estimate of 1.2 x 10(7) base pairs for the genome of T. parva. Repetitive restriction fragments were cloned from two samples, separated from the recombinant vectors and used as probes to demonstrate RFLPs between isolates. Discrimination into five groups was achieved. Schizont and piroplasm DNAs from the same isolate gave identical RFLPs, and one of the cloned parasites appeared to be a sub-population selected from a mixed-infection field isolate. Comparison of RFLPs with monoclonal antibody profiles suggested that neither technique yet provides discrimination between all the isolates which may comprise a strain. The importance of DNA probes for studying the epidemiology of theileriosis and for control programs is discussed.

Animals↗
PubMed1987

Interspecific characterization of several taeniid cestodes by isoenzyme analysis using isoelectric focusing in agarose.

Taenia cestodes were obtained from 5 different definitive host species in Kenya and 175 different samples were examined by classical morphological methods and by isoenzyme analysis using isoelectric focusing in agarose. Gels were stained for 17 different enzymes and 3 of these were used in the construction of isoenzyme profiles. The samples fell into 25 zymodemes, and no zymodeme contained more than 1 species of Taenia, indicating that isoenzyme analysis can reliably be used for the identification of species of this genus.

Animals↗
PubMed1983

Isoelectric focusing in agarose: a highly discriminatory method for the detection of enzyme heterogeneity.

A comparison was made of the effectiveness of starch gel electrophoresis and isoelectric focusing in agarose for the separation of isoenzymes. Lactate dehydrogenase (LDH) of Theileria parva and glucose phosphate isomerase (GPI) of various cestodes were examined by the two techniques. Isoelectric focusing proved to be highly discriminatory, clearly distinguishing cestode orders and Taenia spp. which were closely similar by starch gel electrophoresis, and separating seven bands of Theileria-specific LDH activity which were not separable from normal bovine control bands on starch gels. The routine use of isoelectric focusing in agarose is therefore recommended for isoenzyme analysis.

Animals↗
PubMed1982

Surface membrane components of Theileria spp piroplasms and associated complement fixation activity.

Theileria parva (parva) piroplasms were examined for complement fixation (CF) activity with sera from cattle immune to T parva (parva) (Muguga). The piroplasms were found to be highly antigenic, and the antigens responsible for this CF reactivity were completely insoluble in aqueous media. The antigens were traced through a variety of fractionation procedures and the fractions examined by electrophoresis in the presence of sodium docedyl sulphate. Antigenically active preparations were found always to contain two polypeptides having molecular weights of 21,500 and 34,000. When intact piroplasms were surface labelled with iodine 125 these same two polypeptides were the most heavily labelled, which suggested that the antigens responsible for the CF reactivity were plasma-membrane bound. Electrophoretic analysis of fractions containing plasma membrane components from piroplasms of three species of Theileria (T parva [parva], T mutans and T taurotragi) enabled interspecific differentiation to be made. Three stocks of T parva (parva) could not be differentiated by this means; such different stocks, from various locations within East Africa, appeared to be identical chemically.

Animals↗
PubMed1977

Purification and characterization of precipitating antigens from Theileria parva.

Precipitating antigens from Theileria parva have been partially purified. Two antigens from each of the schizont and piroplasm stages of the parasite were identified; the major antigens from the two stages shared the same specificity. The antigens showed considerable molecular heterogeneity, almost certainly a result of the preparative method, and they always contained large amounts of DNA. The piroplasm antigens were of parasite nuclear origin and the schizont antigens were probably of the same origin. The antigens were weakly antigenic, and the activity against them of humoral antibody from cattle immune to East Coast fever was low. These antigens do not appear to induce protection against East Coast fever.

Animals↗