Showing papers in "Molecular and Biochemical Parasitology in 1999"

TL;DR: A dual-promoter approach is developed, for expressing highly toxic products and generating conditional gene knock-outs, using back-to-back constitutive T7 and tetracycline-responsive PARP promoters to drive expression of the selectable marker and test gene, respectively.

TL;DR: The agent of Chagas disease, Trypanosoma cruzi, is divided into two highly divergent genetic subgroups, lineages 1 and 2, which include all typed strains isolated from humans, insect vectors, and sylvatic mammals, which are likely to be distinct species, or at least subspecies because of their different ecological and epidemiological traits.

TL;DR: The wide distribution of the Ac-asp-2 in nematodes and its release in response to host specific signals suggests that Ac-ASP-2 serves an important function in nem atode physiology and development, and possibly in the infective process of parasitic species.

TL;DR: A significant influence of the genetic polymorphism of infecting T. cruzi populations in the pathogenesis of chronic Chagas disease is indicated by the results of a low-stringency single specific primer polymerase chain reaction test.

TL;DR: Cross-linking studies established that GRA4 and GRA6 specifically interact with GRA2 to form a multimeric complex that is stably associated with the intravacuolar network.

TL;DR: A cluster of var genes on chromosome 12 that showed spontaneous recombination and switches in the transcription of individual genes suggest epigenetic regulation of P. falciparum var gene transcription that depends upon the local structure of chromatin and its associated proteins.

TL;DR: Investigating the fate of FP in cultured Plasmodium falciparum -infected human red blood cells revealed a straight correlation between amounts of digested hemoglobin and hemozoin, but the latter contained less FP than produced, implying the antimalarial mode of action of chloroquine and amodiaquine is different in its mechanistic details from that of quinine and mefloquine.

TL;DR: Characterization of PvMSP-3 begins to define a new interspecies family of evolutionarily related Plasmodium merozoite proteins, which is associated with but not anchored in the merozosite membrane.

TL;DR: A reverse transcriptase polymerase chain reaction (RT-PCR) for detection of gametocytes of P. falciparum is described and this protein and its mRNA molecules are specific to the activated gametocyte and to the zygote and ookinete stages into which it transforms.

TL;DR: Purified leishmanial tubulin is recognized by commercially available anti-tubulin antibodies and displays concentration dependent assembly in vitro, and electrophilic compounds such as phenyl arsenoxide and 4-chloro-3,5-dinitro-alpha, alpha,alpha,alpha-trifluorotoluene (chloralin), which are of interest as traditional and experimental antiparasitic agents, inhibit the assembly of leishmania tubulin in vitro as well.

TL;DR: Evidence is provided that the antimalarial activity of atovaquone indeed involves an interaction with the cytochrome b and amino acid residues in the mammalian cy tochrome b which might be critical in determining its relative resistance to atovaaquone are defined.

TL;DR: The results show that recombinant K26 is specific in detecting antibodies in infection sera from visceral leishmaniasis (VL) patients and may complement rK39 in a more accurate diagnosis of VL in the old and the new world.

TL;DR: PTK antagonists such as genistein, herbimycin A, geldanamycin and tyrphostin 25 had no significant effect on adhesion to, or entry into, murine peritoneal macrophages, but increased parasite intracellular survival.

TL;DR: Evidence that certain conserved sequences recur in clones from one Sudanese village and in isolates from all over the world suggests that var gene diversity is the result of recombinational reshuffling of a subset of conserved, presumably ancestral sequences.

TL;DR: The successful expression of recombinant P. falciparum HGXPRT in Escherichia coli has now been achieved and the enzyme purified to homogeneity in mg quantities, and a method to stabilise the activity and to reactivate inactive samples has been developed.

TL;DR: Southern blot analyses indicated variations in number and size of homologous chromosomes between various E. histolytica isolates, but only minor differences were observed between clones of a given isolate.

TL;DR: This is the first HDAC gene isolated from the malaria parasite and the protein is named, PfHDAC1, as the sequence shows significant homology to yeast, human and other eukaryotic HDACs.

TL;DR: The identification of a second P. falciparum subtilisin-like merozoite protein, called PfSUB-2, which is encoded by a single copy gene and expressed as a large putative type I integral membrane protein which undergoes extensive post-translational processing.

TL;DR: While in procyclic stages of T. brucei G6PDH activity is present in two different cell compartments, i.e. the cytosol and the glycosomes, these two activities most likely represent one and the same isoenzyme.

TL;DR: The results indicate the possibility of frequent genetic exchange in the field, imply that a significant proportion of mammalian hosts must contain mixtures of different trypanosome genotypes and demonstrate the advantages of using minisatellite markers for the analysis of the population structure of T. brucei.

TL;DR: The peptide aldehydes are able to arrest parasite growth in vitro with the same relative effectiveness as against the purified proteasome activity, indicating that, in part, the essential nature of the proteasomes for L. mexicana proliferation is due to a role in the parasite cell cycle.

TL;DR: Using successive rounds of gene replacement of the three ORFG genes in L. donovani LSB-51.1, ORFG null mutants were obtained and the null mutants are unable to grow in the absence of supplemental biopterin and has been renamed BTI.

TL;DR: The results showed that amastigotes have a simpler sterol biosynthetic pathway than that previously described for epimastigote, lacking both delta5 and delta22 reductases, and suggest that the 100-fold higher potency of antifungal azoles as antiproliferative agents against amastIGotes, when compared with epimastsigotes, is most probably due to a smaller pool of endogenous sterols in the intracellular parasites.

TL;DR: The results suggest that a single p67 polypeptide is synthesized in both bloodstream and procyclic trypanosomes and that subsequent post-translational processing and lysosomal targeting is subject to stage-specific regulation.

TL;DR: It is suggested that many expression site promoters in trypanosomes show low-level activity throughout the life cycle, and that transcription proceeds for at least 5 kb, which suggests a simplified model of VSG expression site control, whereby the only regulated event is the strong activation of a single expression site promoter in bloodstream forms.

TL;DR: This report represents the first description of a minimal and necessary cis-acting sequence element for efficient promoter activity in P. falciparum, supporting the notion that the protozoan parasites has evolved a transcriptional machinery distinct from that of its human and mosquito hosts.

TL;DR: The TRAP A-domain shares certain binding properties already attributed to the region II-plus-like domain of TRAP, and may contribute to the binding of TR AP to heparan sulfate on hepatocytes.

TL;DR: Two major protein phosphatase activities were purified from cytosolic extracts of the erythrocytic stage of the malaria parasite, Plasmodium falciparum, and both enzymes were specific for phosphoserine and phosphothreonine residues with very little activity against phosphotyrosine residues.