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Biomedical subjects

R J Wilson

Publications and source records attributed to R J Wilson.

At least 199 records · Page 11Linked to original sources
PubMed1968

The kinetics of a novel cyclic reaction system and its use in the assay of polynucleotide phosphorylase or adenosine diphosphate plus adenosine triphosphate.

1. A sensitive new method is described for the rapid optical assay of polynucleotide phosphorylase in crude bacterial extracts of low specific activity. 2. The assay is non-linear with time and a quick method for determining the approximate activity by using a nomograph is given. 3. The dependence of the assay on Mg(2+) concentration was investigated and the conditions that gave first-order kinetics were determined. 4. The theoretical behaviour of the system was examined mathematically and shown to tend to a simple dynamic steady state, under certain conditions. 5. The potential uses of such cyclic systems are discussed.

Adenine Nucleotides↗
PubMed1968

The preparation and kinetics of lactate dehydrogenase attached to water-insoluble particles and sheets.

1. The preparation of lactate dehydrogenase covalently attached to anion-exchange cellulose particles and sheets by use of a dichloro-sym-triazinyl dyestuff, Procion brilliant orange MGS, is described. 2. The stability and kinetic properties of these preparations were investigated. 3. An equation is derived to describe the change in concentration of a substrate when passed through a uniform bed of a substrate-inhibited enzyme. A number of theoretical curves are shown to illustrate the system. 4. A titrimetric assay for lactate dehydrogenase is described, and shown to be stoicheiometric over the range pH5.0-9.2. 5. The results are discussed in relation to previous work, and the effects of charged groups on the support, and of the diffusion film surrounding any particle in suspension, are treated qualitatively.

Cellulose↗
PubMed1968

The preparation and properties of pyruvate kinase attached to porous sheets, and the operation of a two-enzyme continuous-feed reactor.

1. The covalent attachment of pyruvate kinase to filter-paper disks and some kinetic properties of the resultant enzymically active porous sheets are described. 2. A two-enzyme reactor was constructed by using water-insoluble sheets of lactate dehydrogenease in conjunction with the above-mentioned sheets possessing pyruvate kinase activity.

Adenine Nucleotides↗
PubMedDate not supplied

Control of malarial invasion by phosphorylation of the host cell membrane cytoskeleton.

It has been shown that the entry of the malaria parasite into the red blood cell requires the presence of ATP in the host cell cytoplasm. In red blood cell ghosts that contain no ATP the receptor on the extracellular surface remains in place and parasites will bind to the membrane, but will not enter. ATP is thus necessary for one of the steps in the invasion sequence that follows recognition and attachment. The process of entry appears to involve the active participation of the host cell membrane cytoskeleton. We have suggested that the function of the intracellular ATP may be to regulate phosphorylation of the cytoskeleton. We now present evidence that the activity of the membrane-associated cyclic AMP-independent kinase of the red blood cell is inseparable from invasion; the active substrate may be spectrin.

Animals↗
PubMedDate not supplied

The putative mitochondrial genome of Plasmodium falciparum.

Intraerythrocytic stages of mammalian malarial parasites employ glycolysis for energy production but some aspects of mitochondrial function appear crucial to their survival since inhibitors of mitochondrial protein synthesis and electron transport have antimalarial effects. Investigations of the putative mitochondrial genome of Plasmodium falciparum have detected organellar rRNAs and tRNAs encoded by a 35 kb circular DNA. Some features of the organization and sequence of the rRNA genes are reminiscent of chloroplast DNAs. The 35 kb DNA also encodes open reading frames for proteins normally found in chloroplast but not mitochondrial genomes. An apparently unrelated 6 kb tandemly repeated element which encodes two mitochondrial protein coding genes and fragments of rRNA genes is also found in malarial parasites. The malarial mitochondrial genome thus appears quite unusual. Further investigations are expected to provide insights into the possible functional relationships between these molecules and perhaps their evolutionary history.

Animals↗