Showing papers in "Molecular and Biochemical Parasitology in 1984"

TL;DR: The pathways leading to purine and pyrimidine nucleotide production in members of the family Trypanosomatidae are discussed with special emphasis on data relating to pathogenic species published from 1974 to 1983 inclusive.

TL;DR: The present results suggest that the P. knowlesi antigen reactive with the inhibitory monoclonal antibodies may have particular interest as a vaccine against P.knowlesi malaria.

TL;DR: Thymidylate synthetase and dihydrofolate reductase exist as a bifunctional protein in a number of species of protozoa which span diverse groups of the subkingdom and it is likely that the bifunctionsal protein is widespread among these primitive eukaryotes.

TL;DR: Little variance in enzyme composition was found between the different species of Leishmania or in comparison with other members of the Trypanosomatidae, supporting the unifying principle that glycosomes are a unique characteristic of this family.

TL;DR: Lanosterol and 4,4-dimethylcholesta-8,24-dien-3 beta-ol were detected in all species studied, and squalene was identified in a stock of L. tropica.

TL;DR: DNA synthesis in cultures of tightly synchronized, developing, asexual forms of Plasmodium falciparum began during the early trophozoite stage between 29 and 31 h after parasite invasion and continued through most of the remainder of schizogony, where DNA synthesis was inhibited by both hydroxyurea and aphidicolin.

TL;DR: Highly purified glycosomes were isolated from Trypanosoma brucei bloodstream forms and cultured procyclic trypomastigotes and a comparison of the specific activities of glycosomal enzymes revealed that glycosome from insect stages had decreased levels of hexokinase, but contained increased levels of adenylate kinase, malate dehydrogenase and phosphoenolpyruvate carboxykinase.

TL;DR: Ketoconazole was found to inhibit growth and impair sterol biosynthesis of the cultured promastigote stage of Leishmania mexicana Walter Reed 227 in human monocyte-derived macrophages and the mechanism of action may be that postulated for Candida albicans: interference with membrane permeability secondary to loss of desmethyl sterols and accumulation of 14 alpha- methyl sterols.

TL;DR: Adult and muscle larvae may be more resistant to killing by leukocytes than newborn larvae because they contain better oxidant defenses, according to the effects of artificially generated oxidants.

TL;DR: The biosynthesis of three proteins previously identified on the surface of extracellular gametes of Plasmodium falciparum as the targets of monoclonal antibodies are studied to find that these proteins are synthesized by gametocytes from an early stage in their maturation but are not synthesizing by asexual blood stage parasites.

TL;DR: Calculations are presented which demonstrate that the Krebs-cycle activity of the developing F. hepatica is directly proportional to the surface area of the fluke, which supports the view that Krebs -cycle activity is limited by the diffusion of oxygen and can only occur in the outer layer of the liver fluke during its entire development in the final host.

TL;DR: It is shown that P190 undergoes processing and is lost at release/re-invasion, correlating with a lack of 7.3 immunofluorescence reactivity on rings.

TL;DR: A monoclonal antibody (13C11) was used to investigate the processing of a Plasmodium knowlesi plasma membrane protein during the late stages of schizogony and found that it bound to the surface of merozoites, blocked invasion of erythrocytes and immunoprecipitated a 230 kDa glycoprotein from metabolically labelled schizonts.

TL;DR: Results of the cytochemical assays demonstrated the biochemical and structural asymmetry of the isolated parasite surface membrane with regard to the localization and distribution of the active sites of these two enzymes.

TL;DR: The analysis of kDNA from two L. tropica strains isolated at 14 year intervals from a patient with leishmaniasis recidivans has shown that the two strains are closely related, suggesting that the individual suffered the cutaneous disease as a result of a resurgence of the same parasite which caused the initial infection.

TL;DR: The cholesterol synthesis of rhesus monkey erythrocytes parasitized by Plasmodium knowlesi and human ery Throcytes infected by P. falciparum, as measured by incorporation of [1-14C]acetate and 3H2O, was almost undetectable, concordant with very low levels of measurable 3-hydroxy-3-methyl glutaryl-CoA reductase activity.

TL;DR: Kinetoplast DNA was extracted from marker isolates of three 'Old World' cutaneous leishmania, L. aethiopica and L. major showing that each isolate produced a unique pattern of DNA fragments.

TL;DR: Development of anaerobic metronidazole resistance in T. foetus depended on the loss of pyruvate:ferredoxin oxidoreductase as well as on the ability to increase alcoholic fermentation.

TL;DR: Mid-log phase Leishmania donovani promastigotes accumulated 2-deoxy-D-glucose (2-DOG) via a carrier mediated transport system, maintaining an apparent Km of 24.4 microM and a Vmax of 3.12 nmol mg-1 protein min-1.

TL;DR: None of the molecules can be detected in newly invaded ring stage parasites, indicating that they are either excluded when the merozoite invades, or if internalised, they rapidly undergo further structural alteration since newly parasitised red cells no longer contain epitopes which react with the inhibitory monoclonal antibodies.

TL;DR: It is found that a curare-sensitive mechanism is involved in the excitation of the excitatory motorneuron via interneurons, and AVM has two distinct sites of action in A. suum.

TL;DR: Analysis of genomic DNA from parasites obtained after passage of KA through the tick vector suggested that a subpopulation was being selected that more closely resembled KV than KA, and suggested that most isolates are comprised of a heterogeneous mixture of subpopulations.

TL;DR: T. vaginalis has no appreciable dihydrofolate reductase or thymidylate synthetase; it grows normally in millimolar concentrations of methotrexate, pyrimethamine, or trimethoprim, and cannot incorporate labels from exogenous uracil or uridine into DNA, but has an enzyme thymidine phosphotransferase in the sedimentable fraction which converts thymazine to TMP.

TL;DR: A soluble aminopeptidase from Plasmodium falciparum was purified by high performance liquid chromatography and indicated the presence of a group on the free enzyme, pKa = 6.6, which must be in the conjugate base form for activity.

TL;DR: CDNA clone banks prepared from adult mRNA will therefore contain the genes for these schistosomulum surface antigens greatly facilitating their isolation, suggesting that at least some of the surface proteins of the young Schistosoma mansoni are being synthesised throughout the life cycle.

TL;DR: Determination of the pH optima of the enzyme forms separated by isopycnic centrifugation suggests that the glycosomal enzyme form is MDHa, and the mitochondrial one is MDHb.

TL;DR: All purine nucleosides are primarily converted to the corresponding purine bases via individual purine phosphoribosyl transferases, which constitute the major network for purine salvage in S. mansoni schistosomules.

TL;DR: Surface-labelled proteins of apparent Mr equal to or greater than 55 000 on the female gametes and newly fertilized zygotes were shed during transformation and were recovered quantitatively and apparently intact from the culture supernatant.

TL;DR: It was concluded that the major basis for drug resistance is not an increase in enzyme content, but a large decrease in drug binding with the structurally different enzyme.