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Biomedical subjects

P I Payne

Publications and source records attributed to P I Payne.

16 recordsLinked to original sources
PubMed1988

GESA--a two-dimensional processing system using knowledge base techniques.

The successful analysis of two-dimensional (2-D) polyacrylamide electrophoresis gels demands considerable experience and understanding of the protein system under investigation as well as knowledge of the separation technique itself. The present work concerns the development of a computer system for analysing 2-D electrophoretic separations which incorporates concepts derived from artificial intelligence research such that non-experts can use the technique as a diagnostic or identification tool. Automatic analysis of 2-D gel separations has proved to be extremely difficult using statistical methods. Non-reproducibility of gel separations is also difficult to overcome using automatic systems. However, the human eye is extremely good at recognising patterns in images, and human intervention in semi-automatic computer systems can reduce the computational complexities of fully automatic systems. Moreover, the expertise and understanding of an "expert" is invaluable in reducing system complexity if it can be encapsulated satisfactorily in an expert system. The combination of user-intervention in the computer system together with the encapsulation of expert knowledge characterises the present system. The domain within which the system has been developed is that of wheat grain storage proteins (gliadins) which exhibit polymorphism to such an extent that cultivars can be uniquely identified by their gliadin patterns. The system can be adapted to other domains where a range of polymorpic protein sub-units exist. In its generalised form, the system can also be used for comparing more complex 2-D gel electrophoretic separations.

Algorithms↗
PubMed1987

Chromosomal location of genes coding for endosperm proteins of Hordeum chilense, determined by two-dimensional electrophoresis of wheat-H. chilense chromosome addition lines.

The proteins of Hordeum chilense grain were resolved into 25 major components by two-dimensional electrophoresis. Their solubilities in aqueous alcohol solutions were determined to distinguish prolamin storage proteins from metabolic and structural proteins. The prolamins were divided into two groups, based on the presence or absence of intermolecular disulfide bonds determined by gel-filtration chromatography. Using an incomplete set of Chinese Spring wheat-H. chilense disomic addition lines, the structural genes of 21 of the 26 most dominant seed proteins were assigned to chromosomes. The great majority of the prolamin genes, including those coding for a high molecular weight (HMW) prolamin subunit, was present on chromosome 1 Hch. However, a small number of prolamin genes also occurred on chromosomes 5 Hch and 7 Hch. A minor protein, probably belonging to the nonstorage group of proteins, is coded by genes on 5 Hch. Various ditelosomic addition lines and ditelosomic and disomic substitution lines for chromosome 7 Hch were also analyzed by electrophoresis. This technique revealed that the genes for three major prolamins occur on the beta arm of chromosome 7 Hch and that a gene for a minor protein, also thought to be a prolamin, occurs on the alpha arm. These results are discussed in relation to the evolution of prolamin genes in the Triticeae.

Chromosome Mapping↗
PubMed1976

Evidence for the nucleotide sequence of 5-S rRNA from the flowering plant Secale cereale (Rye).

Evidence for the sequence of rye 5-S rRNA was derived from the analysis of partial and complete enzymic digests of the 32P-labelled molecule. The probable sequence of 5-S rRNA from four other flowering plants was deduced by aligning, with the homologous sequences in the rye 5-S rRNA, oligonucleotides produced by T1 and pancreatic A ribonuclease digestion. The most dissimilar differed in only seven positions. From a comparison of the sequence of rye 5-S rRNA with those known for other types of organism, it was possible to distinguish some structural features of the molecule which are common to all of them. Also, information was obtained about the possible phylogenetic relationship of the flowering plants to other organisms whose 5-S rRNA has been sequenced.

Base Sequence↗
PubMed1975

Early ribonucleic acid synthesis during the germination of rye (Secale cereale) embryos and the relationship to early protein synthesis.

Incorporation studies with radioactive precursors showed that synthesis of protein and RNA is initiated in germinating embryos of rye within the first hour of imbibition of water. By polyacrylamide-gel fractionations of radioactive nucleic acid components, the appearance of products of transcription of the genome was shown to follow the sequence: heterogeneous (ribonuclease-sensitive) RNA, 4S and 5S RNA by 20min, 31S and 25S rRNA by 40min, and 18S RNA by 60min. "Fingerprint' analysis of T1-ribonuclease digests show that all the large oligonucleotides present in 25S and 18S RNA are present in the 31S species, indicating that 31S RNA is the precursor rRNA molecule to both 25S and 18S RNA. The importance of these early RNA syntheses and in particular the possible template function of the heterogeneous RNA is discussed in relation to the concept of long-lived mRNA and the coding for protein synthesis in the first hours of germination.

Edible Grain↗
PubMed1973

Protein synthesis and the viability of rye grains. Loss of activity of protein-synthesizing systems in vitro associated with a loss of viability.

A study was made of the integrity of some components of the protein-synthesizing system from viable and non-viable embryos of rye grains. In comparison with viable-embryo components both post-ribosomal supernatant and ribosomal fractions from non-viable embryos are impaired, for neither will fully support polyphenylalanine synthesis in poly(U)-directed cell-free systems. The lesion in the supernatant lies in components other than the tRNA or the aminoacyl-tRNA synthetase, for these are as functional as those present in the fully active cell-free systems from viable embryos. The ribosomes of embryos of lowered viability show considerable fragmentation and degradation of both 18S and 25S rRNA. This breakdown does not, however, account for the complete lack of polypeptide synthesis in the poly(U)-directed non-viable-embryo system, for if provided with viable-embryo supernatant, non-viable-embryo ribosomes will sustain 60% of the viable-embryo ribosome activity. A lesion in non-viable-embryo supernatant has been located in the binding of the aminoacyl-tRNA to the ribosome. The impaired components in both supernatant and ribosomes in systems in vitro may reflect the site of faults in protein synthesis in vivo in the early hours of germination. The development of these lesions during grain storage could contribute to senescence and loss of viability in the embryos of rye.

Amino Acids↗
PubMed1973

Nucleotide sequence analysis of the cytoplasmic 5S ribosomal ribonucleic acid from five species of flowering plants.

Broad-bean 5S rRNA labelled with (32)P was digested separately with T(1) and pancreatic A ribonucleases and the resulting oligonucleotides (20 and 18 respectively) were fractionated by two-dimensional electrophoresis. The oligonucleotides were analysed further and 32 of them have been completely sequenced. They were compared with those of 5S rRNA from dwarf bean, sunflower, tomato and rye. Sequence differences were found at both the 3'- and 5'-termini and at up to nine other positions. Most base substitutions were transitions between C and U. In common with other 5S rRNA species that have been analysed the ends of the molecule in each plant species have complementary sequences.

Autoradiography↗
PubMed1971

Characterization of cytoplasmic and chloroplast 5S ribosomal ribonucleic acid from broad-bean leaves.

Green leaves of the broad bean (Vicia faba) contain two 5S RNA components that can be separated from each other by polyacrylamide-gel electrophoresis. The major component is located in the larger subunit of cytoplasmic ribosomes, whereas the minor component occurs in the larger subunit of chloroplast ribosomes. Their electrophoretic mobilities relative to those of Escherichia coli 5S RNA (120 nucleotides) and plant 4S RNA (78 nucleotides) suggest that they consist of 118 and 122 nucleotide residues respectively. Thermal ;melting' profiles of plant cytoplasmic and chloroplast 5S RNA species at 260nm indicate the similarity of their secondary structures, not only to each other, but also to those of E. coli and mammalian 5S RNA species. The base compositions of the two plant 5S RNA species have more in common with each other than with the corresponding molecules from either E. coli or mammalian cells.

Acrylates↗