Biomedical subjects

B Fenton

Publications and source records attributed to B Fenton.

41 records · Page 3Linked to original sources

PubMed1987

Peptide digest studies of polymorphic proteins of Plasmodium falciparum.

Previous work has shown that when a large number of Plasmodium falciparum isolates are examined by two dimensional electrophoresis, over 100 different proteins can be detected, 15 of which show polymorphism in electrophoretic characters. Eight of these proteins have now been subjected to limited proteolysis. Two methods of digestion were used: enzymic, with Streptomyces griseus Pronase E and chemical, using N-chlorosuccinimide to break proteins at tryptophan residues. When different forms of each variable protein were analysed most were found to exhibit similar peptide profiles, a finding indicating that they were determined by alleles of genes at single loci. Two of the proteins, A and K, exhibited higher degrees of polymorphism than the other variable proteins. The possible reasons for this are discussed.

Animals↗

PubMed1987

Polymorphism of proteins in malaria parasites following mefloquine treatment.

Proteins in malaria parasites (Plasmodium falciparum) isolated from a patient in Thailand before treatment, and after recrudescence of infection subsequent to mefloquine treatment, were compared by two dimensional polyacrylamide gel electrophoresis (2D-PAGE) analysis. Nine 'pre-treatment' and six 'recrudescent' clones were studied. Variants of the enzyme glucose phosphate isomerase were also noted and mefloquine susceptibility of each clone was measured by in vitro tests. The 'pre-treatment' isolate was found to contain at least four genetically distinct clones, all sensitive to mefloquine, while the 'recrudescent' isolate contained at least two other types of clone, both showing increased tolerance to mefloquine. These two more tolerant types of clone differed from all the sensitive ones studied in regard to several different protein variants as shown by 2D-PAGE analysis. It is concluded that at least two (and probably more) genetically distinct clones of parasites with increased tolerance to mefloquine were present in the parasite population before mefloquine treatment was given, and were selected under mefloquine pressure.

Animals↗

PubMed1985

Protein variation in clones of Plasmodium falciparum detected by two dimensional electrophoresis.

Two dimensional electrophoresis has been used to examine protein variation in clones of two Plasmodium falciparum isolates. Variant forms of 12 proteins were detected. Five genetically distinct parasite types were identified in one isolate, and two in the second isolate. Examination of uncloned parasites using this technique showed that the frequency of each genotype altered during six months of culture.

Animals↗

PubMed1984

Clonal diversity in a single isolate of the malaria parasite Plasmodium falciparum.

Clones of an isolate of Plasmodium falciparum from Mae Sod (Thailand) were prepared by a dilution procedure. Some of the parasite cultures thus obtained have been typed for the following characters: (i) electrophoretic variants of three enzymes; (ii) susceptibility to chloroquine and pyrimethamine; (iii) antigen diversities recognized by ten strain-specific monoclonal antibodies; (iv) presence or absence of knobs on infected erythrocytes and (v) two-dimensional PAGE variants of seven proteins. Amongst the clones there was variation involving each of these five characters. At least seven different types of clones were found in ten cultures produced by dilution. The amount of phenotypic variation within a single isolate has thus been shown to be surprisingly great. Variations in drug susceptibility and antigens are considered to be particularly important in view of their relevance to anti-malarial treatments.

Animals↗

PubMedDate not supplied

Genetic diversity of Plasmodium falciparum in a village in eastern Sudan. 1. Diversity of enzymes, 2D-PAGE proteins and antigens.

Twenty-nine plasmodium falciparum isolates from patients in Asar village, eastern Sudan, were characterized for variation in 18 different genetically controlled characters, including iso-enzymes, proteins detected by two-dimensional polyacrylamide gel electrophoresis and blood-stage antigens. Considerable allelic diversity in the genes determining these characters was detected. Each isolate contained genetically distinct parasites. Fifteen individuals were infected with more than one parasite genotype. The diversity of parasite types is most probably generated by recombination during mosquito transmission of mixed parasite clones.

Animals↗