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J S Cordingley

Publications and source records attributed to J S Cordingley.

30 records · Page 2Linked to original sources
PubMed1984

Immunoprecipitation of surface antigen precursors from Schistosoma mansoni messenger RNA in vitro translation products.

Messenger RNA has been isolated from adults and eggs of Schistosoma mansoni and translated in vitro in mRNA dependent rabbit reticulocyte lysate. The in vitro translation products have been immunoprecipitated using a wide variety of hyperimmune and infection sera from rabbits, mice and humans. A large number of in vitro translation products are precipitated by these sera, and we have identified a subset of the immunoprecipitated polypeptides which are expressed on the surface of the young schistosomulum. Messenger RNA from both adults and eggs directs the synthesis of these polypeptides suggesting that at least some of the surface proteins of the young schistosomulum are being synthesised throughout the life cycle. cDNA clone banks prepared from adult mRNA will therefore contain the genes for these schistosomulum surface antigens greatly facilitating their isolation.

Animals↗
PubMed1984

Genetic engineering and a schistosome vaccine.

Early attempts to develop a vaccine against schistosomiasis have been largely empirical, relying on use of live, attenuated larvae or homogenates and extracts of the various life-cycle stages of the parasite. Although some success has been reported using attenuated larvae, by and large the early attempts at vaccination have proved unsuccessful. Recently, we have begun to apply recombinant DNA technology to the problem of schistosome vaccine development. A majority of the evidence pertaining to immunity against schistosome infection suggests that the schistosomula is the primary target of the immune attack. Therefore, it follows that antigens found on the surface of the young larvae would be prime candidates for inclusion in an experimental vaccine. This lecture summarizes work aimed at the identification of schistosomula surface antigens and molecular cloning of their corresponding genes. cDNA clones have been prepared from both egg and adult mRNA. Relevant clones have been identified by "message" selection. This approach relies on identification of relevant antigen precursors among in vitro translation products. At least 5 schistosomula surface-antigen precursors have been recognised among in vitro translation products directed by adult mRNA. Some of these peptides are also encoded by mRNA isolated from eggs. One egg-specific peptide has been cloned and there is evidence that this is immunodiagnostic for Schistoma mansoni infections. A long-term aim is hoped that such molecules would contribute to a schistosome vaccine as well as providing immunodiagnostic reagents.

Animals↗
PubMed1984

Ribosomal RNA genes of Trypanosoma brucei: mapping the regions specifying the six small ribosomal RNAs.

There are six small ribosomal RNAs in trypanosome ribosomes. sRNA3 and sRNA5 of Trypanosoma brucei brucei have been partially sequenced. Sequence homologies indicate that sRNA3 is 5.8S RNA and sRNA5 is 5S RNA of T. b. brucei. The regions specifying these two, and the remaining four small RNAs, have been identified within clones of rRNA genes and in the genome. Five of the small RNAs, 1, 2, 3, 4 and 6, hybridise exclusively within the major rRNA gene repeat. A map of the regions specifying these small RNAs is presented. sRNA3 (5.8S RNA) hybridises to a region corresponding to the transcribed spacer of other eukaryotes. sRNA1 hybridises to a region between sequences specifying the two large subunit RNA molecules of 2.3 kb and 1.8 kb. Sequences specifying sRNAs 2 and 4 are present near the sequence specifying sRNA1, while sRNA6 appears to be specified 3' to the sequence specifying the 1.8-kb RNA sequence. In addition regions of secondary hybridisation for small RNAs 2, 3, 4 and 6 have also been identified. Though sRNA5 (5S RNA) hybridises within the major rRNA repeat, a separate 5S RNA gene repeat with unit size of 760 bp is also present. It is 10 to 20 times more abundant than the major rRNA gene repeat.

Animals↗
PubMed1983

Clone banks of cDNA from the parasite Schistosoma mansoni: isolation of clones containing a potentially immunodiagnostic antigen gene.

We have constructed a small vector specifically for blunt-end cloning of fragments of DNA. Both the PvuII site and the EcoRI site allow the detection of recombinants using a simple and inexpensive colour screen. We have used this vector to construct cDNA clone banks from polyadenylated messenger RNA [poly(A)+mRNA] from several life cycle stages of the human parasite Schistosoma mansoni and have identified clones encoding an immunodiagnostic antigen gene by a combination of Southern blotting and mRNA hybrid-selection and in vitro translation. Antibodies against this antigen are only present in patients infected with S. mansoni.

Animals↗
PubMed1982

Ribosomal RNA genes of Trypanosoma brucei. Cloning of a rRNA gene containing a mobile element.

An ordered restriction map of the ribosomal RNA genes of Trypanosoma brucei brucei is presented. Bgl II fragments of T.b.brucei genomic DNA were cloned into pAT 153, and the clones containing rDNA identified. Restriction maps were established and the sense strands identified. One clone was shown by heteroduplex mapping to contain a 1.1 kb inserted sequence which was demonstrated to be widely distributed throughout the genomes of members of the subgenus Trypanozoon. However, in two other subgenera of Trypanosoma, Nannomonas and Schizotrypanum, the sequence is far less abundant. Analysis of the genomic DNA from two serodemes of T.b.brucei showed that the sequence was present in the rRNA of only one of them, implying that the sequence is a mobile element and that its appearance in rDNA is a comparitively recent occurrence.

Animals↗
PubMed1982

The biosynthesis of Trypanosoma brucei variant surface glycoproteins--in vitro processing of signal peptide and glycosylation using heterologous rough endoplasmic reticulum vesicles.

The ability of stripped microsomal dog pancreas vesicles to process precursors of the variant glycoprotein of Trypanosoma brucei has been investigated. The vesicles were shown to be capable of cleaving a peptide precursor variant surface glycoprotein, identified as the N-terminal signal peptide in the case of one variant. The vesicles were also shown to add carbohydrate to precursor variant surface glycoprotein. This carbohydrate, which was sensitive to the action of endo-H was located within a C-terminal CNBr fragment in one variant. However, the vesicles were not capable of adding the oligosaccharide carrying the variant surface glycoprotein cross-reacting determinant.

Animals↗
PubMed1981

Biosynthesis of Trypanosoma brucei variant surface glycoprotein. I. Synthesis, size, and processing of an N-terminal signal peptide.

An N-terminal signal peptide has been identified on a precursor of the variant surface glycoprotein (VSG) of Trypanosoma brucei, synthesised both in vitro and in vivo. An ordered cyanogen bromide (CNBr) cleavage map was constructed for both mature VSG and for precursor VSG, and this allowed a size estimate of the signal peptide to be made by comparison of the N-terminal CNBr peptides produced from each. The signal peptide contains 30-40 amino acids. Analysis of the precursor VSGs produced when nascent polypeptide chains on T. brucei polysomes were completed in the absence of reinitiation showed that the signal peptide is removed before translation is complete and that the same translational start signal is utilised in the trypanosome and in the rabbit reticulocyte protein synthesis system.

Amino Acid Sequence↗
PubMed1980

Esoteric DNA?

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Animals↗
PubMed1980

6.5 S RNA; preliminary characterisation of unusual small RNAs in Trypanosoma brucei.

In this paper we report the preliminary characterisation of some unusual small rRNAs isolated from Trypanosoma brucei. These molecules correspond closely in size and properties to the 5 S and 5.8 S rRNAs of other eukaryotes and in addition there are two further small RNAs which we designate 6.5 S RNA. These have been characterised by sucrose gradient centrifugation and electrophoresis in denaturing gels. The two 6.5 S RNAs may be distinguished from each other on the basis of their size and the different conditions required for their dissociation from the ribosomes. They are present in the same abundance as 5.8 S RNA suggesting that they occur once per ribosome.

Animals↗
PubMed1980

Isolation of Trypanosoma brucei variant specific antigen mRNA by immunoprecipitation of polysomes.

The mRNA encoding the variant specific antigen of Trypanosoma brucei has been prepared by immunoprecipitation of polysomes. Polysomes carrying the variant specific antigen account for approx. 3% of the total polysomes. The mRNA thus produced is active in the mRNA dependent rabbit reticulocyte lysate in vitro protein synthesis system and directs the synthesis of a polypeptide of 60 000 daltons which co-migrates both with 125I-labelled purified variant specific antigen and with antigen immunoprecipitated from reticulocyte lysate charged with total polyadenylated mRNA from the same clone. The mRNA is being used both to prepare cDNA clones and to prepare high specific radioactivity cDNA to be used to screen a gene bank for clones containing variant specific antigen coding sequences.

Animals↗
PubMed1980

Isolation and characterization of polysomes from Trypanosoma brucei.

The isolation of polysomes in bulk from bloodstream forms of Trypanosoma brucei is described. The polysomes are active in in vitro protein synthesis in the presence or absence of initiation inhibitors. Nascent variant surface antigen (VSA) has been detected on these polysomes using purified radio-iodinated antibody. EDTA-induced ribosomal sub-units and their large rRNA's are characterized. The 26S rRNA is nicked to produce 2 molecules which are both smaller than the 19S rRNA of the small sub-unit which is larger than that found in the majority of eukaryotic small sub-units.

Animals↗