Publications
| Title | Abstract | Year Filter | PMID(sorted ascending) Filter |
|---|
| [infection of glossina palpalis palpalis (diptera, glossinidae) by trypanosomes in the forest zone of gagnoa in the ivory coast]. | 2,153 glossina palpalis palpalis caught in biconical traps from different biotopes in relation with human activities in the forest areas of côte d'ivoire were used to calculate the trypanosome infection rates. the results showed that there was no preferential biotope for glossina infected by trypanosomes. the most widespread species of trypanosomes infecting glossina p. palpalis is t. congolense (10.13%) followed by t. vivax (8.22%) and seldomly by t. brucei (0.70%). female glossina are infected ... | 1991 | 1665576 |
| influence of ca2+ depletion on cytoskeleton and nucleolus morphology in trypanosoma brucei. | trypanosoma brucei bloodstream forms were incubated in a calcium-free medium containing 10 microm ethyleneglycol-bis-(beta-aminoethyl ether)-n,n,n',n'-tetraacetic acid (egta). under these conditions, addition of 5 microm calcium ionophore a23187 led to striking morphological alterations, as judged by light and electron microscopy. the cytoskeleton of trypanosomes consists of a subpellicular corset of microtubules. characteristically four of these microtubules are attached invariantly to an exten ... | 1991 | 1666039 |
| pathophysiologic correlates of experimental trypanosomiasis in rabbits. | rabbits inoculated subcutaneously with trypanosoma brucei brucei developed parasitemia, fever, and reduced food and water intake within 4 to 6 days postinoculation. subsequent alterations in clinicopathologic parameters included anemia and increased circulating nucleated red blood cells, fibrinogenemia, hypertriglyceridemia, and hyperproteinemia. transient alterations in the numbers of neutrophils and lymphocytes were detected sporadically; however, leukocytosis was not a characteristic of this ... | 1991 | 1667203 |
| studies of hyperalgesia induced by trypanosoma brucei brucei infection in rats. | sprague-dawley rats were infected by intraperitoneal injections of a strain of trypanosoma brucei brucei. this parasite spreads early to areas in the nervous system which lack a so-called blood-brain or blood-nerve barrier including spinal ganglia. signs of sensory disturbance in the form of hyperalgesia were observed already seven days post infection, using a hot plate analgesimeter. the sensory disturbances progressed and the rats started to lose weight about 3 weeks post infection, and died a ... | 1991 | 1671623 |
| evaluation of dl-alpha-difluoromethylornithine against susceptible and drug-resistant trypanosoma brucei brucei. | the antitrypanosomal activity of the ornithine decarboxylase inhibitor dl-alpha-difluoromethylornithine (dfmo, eflornithine) was tested in ten stocks and one clone of the hemoflagellate trypanosoma brucei brucei in an in vitro system. they showed varying levels of susceptibility to dfmo, their ic50 (the concentration which inhibited growth by 50%) values ranging from 81-691 microm. differences in dfmo susceptibility were also demonstrated in mice. combinations of melarsonyl potassium (mel w; tri ... | 1991 | 1671624 |
| a family of genes related to a new expression site-associated gene in trypanosoma equiperdum. | two genes, belonging to a new expression site-associated gene family of six to eight members in trypanosoma equiperdum and trypanosoma brucei, have been cloned from a t. equiperdum variant. one of them, called esag-9c, is contained in the 1.78-c expression site and is found just upstream of the 5' barren region. the other one, called esag-9u, is unique in the family, is not telomere linked, and apparently is not expression site related. a 2-kb poly(a)+ mrna is detected with probes for this esag- ... | 1991 | 1672441 |
| antitrypanosomal effects of polyamine biosynthesis inhibitors correlate with increases in trypanosoma brucei brucei s-adenosyl-l-methionine. | we reported recently that administration of ([(z)-4-amino-2-butenyl]methylamino)-5'-deoxyadenosine (mdl 73811), an enzyme-activated irreversible inhibitor of s-adenosyl-l-methionine decarboxylase (adometdc; ec 4.1.1.50), a key enzyme in the synthesis of spermidine, cures african trypanosome infections in mice. the precise mechanism of action of mdl 73811 was not clear because a rapid disappearance of trypanosomes from the bloodstream of treated rats occurred before significant depletion of sperm ... | 1991 | 1672500 |
| a novel dna nucleotide in trypanosoma brucei only present in the mammalian phase of the life-cycle. | the existence of an unusual form of dna modification in the bloodstream form of the african trypanosome trypanosoma brucei has been inferred from partial resistance to cleavage of nuclear dna with psti and pvuii (bernards et al, 1984; pays et al, 1984). this putative modification is correlated with the shut-off of telomeric variant-specific surface glycoprotein (vsg) gene expression sites (ess). the modification only affects inactive vsg genes with a telomeric location, and it is absent in procy ... | 1991 | 1674368 |
| hybrid formation in the life cycle of trypanosoma (t.) brucei: detection of hybrid trypanosomes in a midgut-derived isolate. | 1991 | 1674406 | |
| genetic exchange in trypanosoma brucei brucei: variable chromosomal location of housekeeping genes in different trypanosome stocks. | a trypanosoma brucei brucei clone from west africa was crossed with another t. b. brucei clone from the east african kiboko group. this group is defined by characteristic isoenzyme patterns and kinetoplast dna maxicircle polymorphisms, and is associated with a wild animal-tsetse transmission cycle. three types of clone were isolated from the cross, 2 of which were hybrid. the hybrids were heterozygotic at 7 loci where the parents were homozygotic and the hybrids also had molecular karyotypes dif ... | 1991 | 1675762 |
| enhancement of the trypanocidal activity of methyltriazenes in an animal model by the addition of an amidino group. | 1991 | 1678578 | |
| multilocus isozyme identification of trypanosoma brucei stocks isolated in central africa: evidence for an animal reservoir of sleeping sickness in congo. | six congolese and 3 zairian trypanosoma brucei stocks were studied by isozyme cellulose acetate electrophoresis. twenty isozyme systems were used, of which only 5 showed variability. these 5 polymorphic systems made it possible to identify 5 different zymodemes. zymodemes isolated from man were recorded both from pig and sheep too, which confirms the results of previous authors. this favors the existence of an animal reservoir of human african trypanosomiasis in the congo, which could play a rol ... | 1991 | 1680279 |
| elevation of the concentration of acute phase proteins in dogs infected with trypanosoma brucei. | plasma concentrations of the acute phase proteins (app), c-reactive protein (crp) and haptoglobin (hp), increased markedly following experimental infection of dogs with trypanosoma brucei. the highest concentrations of crp were observed immediately after peaks of parasitaemia. treatment with curative doses of the trypanocidal drug suramin caused a rapid decrease in crp. relapse infections after subcurative treatment were followed by a reappearance of high plasma crp concentrations. haptoglobin r ... | 1991 | 1680282 |
| the effect of verapamil alone and in combination with trypanocides on multidrug-resistant trypanosoma brucei brucei. | following previous studies of verapamil reversal of multidrug resistance in cancer cells and chloroquine resistance in malaria, the effect of the calcium channel blocker verapamil was investigated on multidrug-resistant and susceptible trypanosoma brucei brucei. resistance of cloned parasites to diminazene aceturate (berenil) and isometamidium chloride (samorin) was expressed in a cell-free in vitro culture system. verapamil showed antitrypanosomal activity against both, multidrug-resistant and ... | 1991 | 1685302 |
| hybrid formation between african trypanosomes in vitro. | 1991 | 1685305 | |
| biochemical properties of histone-like proteins of procyclic trypanosoma brucei brucei. | four histone-like proteins a, b, c, d were extracted with 0.2 m h2so4 from soluble nuclear chromatin of trypanosoma brucei brucei procyclic culture forms and purified by fplc reversed phase chromatography. the amino acid composition of these proteins and their electrophoretic mobilities in three different gel systems strongly indicated their core histone nature. similarities were found between a, b, c and d with the core histones h3, h2a, h2b and h4 of higher eukaryotes, respectively. on the oth ... | 1991 | 1685873 |
| use of antigen-detection enzyme immunoassays in assessment of trypanotolerance in n'dama cattle. | antigen-detection enzyme immunoassays (elisa) were used for the diagnosis of trypanosoma vivax, t. congolense and t. brucei in n'dama cattle in gabon, central africa. the assays are based on monoclonal antibodies which recognise trypanosome antigens specific for each of the three species and animals were termed 'antigenaemic' when found positive by this technique but not found parasitaemic by the buffy coat technique. 148 one-year-old animals were exposed to a medium natural tsetse challenge and ... | 1991 | 1686140 |
| surface coat synthesis and turnover from epimastigote to bloodstream forms of trypanosoma brucei. | monoclonal antibodies to metacyclic surface coat glycoproteins of trypanosoma brucei brucei stib 247lg were produced for a study of the synthesis of metacyclic variable surface glycoproteins (vsgs) within the salivary gland of glossina morsitans morsitans, and of the first exchange of the surface glycoproteins after infection in mice. immunofluorescence antibody tests and protein a-gold labelling revealed that the vsgs are continuously integrated into the whole surface of the trypanosome while i ... | 1991 | 1686146 |
| genomic organization, chromosomal localization, and developmentally regulated expression of the glycosyl-phosphatidylinositol-specific phospholipase c of trypanosoma brucei. | the surface of the bloodstream form of the african trypanosome, trypansoma brucei, is covered with about 10(7) molecules of the variant surface glycoprotein (vsg), a protein tethered to the plasma membrane by a glycosyl-phosphatidylinositol (gpi) membrane anchor. this anchor is cleavable by an endogenous gpi-specific phospholipase c (gpi-plc). gpi-plc activity is down regulated when trypanosomes differentiate from the bloodstream form to the procyclic form found in the tsetse fly vector. we have ... | 1990 | 1688997 |
| uncoupling of the synthesis of edited and unedited coiii rna in trypanosoma brucei. | rna editing, a novel and unexpected type of information processing, was first demonstrated in the kinetoplasts of certain protozoans. it is a remarkable phenomenon: certain species of messenger rna have nucleotide sequences that differ greatly from the sequences of the genes from which they are presumably transcribed. the differences are usually due to addition of uridylate residues, but occasionally also to their deletion. the most spectacular case of editing known occurs in the mrna of the mit ... | 1990 | 1689017 |
| an rna-dependent ump-incorporating activity is associated with the small subunit of cytoplasmic ribosomes in bloodstream forms of trypanosoma brucei. | trypanosoma brucei cytoplasm contained a ump-incorporating activity which was dependent upon the presence of endogenous rna, stimulated by exogenous rna and precipitable by ammonium sulphate. the activity cosedimented with ribosomes, and after ribosome dissociation using edta was mainly associated with the small (31s) subunit. ribosome-associated activity was selective for utp as a substrate and greatly stimulated by the presence of at least one other nucleoside triphosphate. | 1990 | 1690540 |
| synthesis and secretion of immunoglobulin by spleen cells from resistant and susceptible mice infected with trypanosoma brucei brucei gutat 3.1. | by 6 days after infection of susceptible c3h/he and resistant c57bl/6 mice with trypanosoma brucei brucei gutat 3.1, splenic plasma cell responses of both strains of mice were similar in terms of plasma cell number, intracellular ig, ig secretion, ig class and ig specificity for surface-accessible variant surface glycoprotein (vsg) epitopes on the infecting organisms, despite higher parasitaemia in the c3h/he mice. by 7 days after infection, however, although splenic plasma cells from both strai ... | 1990 | 1690871 |
| regulation of b cell responses to the variant surface glycoprotein (vsg) molecule in trypanosomiasis. i. epitope specificity and idiotypic profile of monoclonal antibodies to the vsg of trypanosoma brucei rhodesiense. | regulatory mechanisms governing b cell responses to the trypanosome variant surface glycoprotein (vsg) molecule currently are being studied. as a fundamental basis for examining such regulation, the epitope specificities and idiotypic profiles of murine mab produced to the vsg of trypanosoma brucei rhodesiense clone loutat 1.5 were determined. variant specific mab were used to probe vsg proteolytic peptides in western blot analysis, to serve as competitive inhibitors in ria analyses with purifie ... | 1990 | 1692071 |
| destruction of u2, u4, or u6 small nuclear rna blocks trans splicing in trypanosome cells. | we have used permeable cells of trypanosoma brucei to analyze the role of snrnas in the trans splicing process. degradation of u2, u4, or u6 snrna by site-directed cleavage with complementary deoxyoligonucleotides and rnaase h inhibits trans splicing of the spliced leader (sl) rna and newly synthesized alpha-tubulin pre-mrnas. cleavage of u snrnas abolishes the appearance of putative trans splicing reaction intermediates and products, namely, linear branched molecules consisting of the sl intron ... | 1990 | 1692263 |
| cell-free synthesis of glycosyl-phosphatidylinositol precursors for the glycolipid membrane anchor of trypanosoma brucei variant surface glycoproteins. structural characterization of putative biosynthetic intermediates. | trypanosome variant surface glycoproteins exemplify a class of eukaryotic cell surface glycoproteins that rely on a carboxyl-terminal covalently-attached inositol-containing glycophospholipid for membrane attachment. the glycolipid anchor is acquired soon after translation of the polypeptide, apparently by replacement of a short carboxyl-terminal peptide sequence with a prefabricated glycolipid. a candidate glycolipid precursor (referred to as p2), and a related glycolipid (p3) have been identif ... | 1990 | 1693147 |
| rna editing involves indiscriminate u changes throughout precisely defined editing domains. | rna editing is the specific posttranscriptional insertion/deletion of u residues within trypanosomatid mitochondrial transcripts. we used a novel cdna cloning scheme and analyzed partially edited coiii and cyb rnas. our major unanticipated findings are: first, editing appears strikingly indiscriminate within editing domains, inserting and deleting variable numbers of u residues at all sites, both those requiring editing and those that do not. second, this incomplete editing occurs in precise dom ... | 1990 | 1693545 |
| procyclic acidic repetitive protein (parp) genes located in an unusually small alpha-amanitin-resistant transcription unit: parp promoter activity assayed by transient dna transfection of trypanosoma brucei. | at least one of the procyclic acidic repetitive protein (parp or procyclin) loci of trypanosoma brucei is a small (5- to 6-kilobase) polycistronic transcription unit which is transcribed in an alpha-amanitin-resistant manner. its single promoter, as mapped by run-on transcription analysis and uv inactivation of transcription, is located immediately upstream of the first alpha-parp gene. transcription termination occurs in a region approximately 3 kilobases downstream of the beta-parp gene. the l ... | 1990 | 1694012 |
| addition of uridines to edited rnas in trypanosome mitochondria occurs independently of transcription. | rna editing is a novel rna processing event of unknown mechanism that results in the introduction of nucleotides not encoded in the dna into specific rna molecules. we have examined the post-transcriptional addition of nucleotides into the mitochondrial rna of trypanosoma brucei. utilizing an isolated organelle system we have determined that addition of uridines to edited rnas does not require ongoing transcription. trypanosome mitochondria incorporate ctp, atp, and utp into rna in the absence o ... | 1990 | 1694178 |
| fatty acid remodeling: a novel reaction sequence in the biosynthesis of trypanosome glycosyl phosphatidylinositol membrane anchors. | the trypanosome variant surface glycoprotein (vsg) is anchored to the plasma membrane via a glycosyl phosphatidylinositol (gpi). the gpi is synthesized as a precursor, glycolipid a, that is subsequently linked to the vsg polypeptide. the vsg anchor is unusual, compared with anchors in other cell types, in that its fatty acid moieties are exclusively myristic acid. to investigate the mechanism for myristate specificity we used a cell-free system for gpi biosynthesis. one product of this system, g ... | 1990 | 1694728 |
| t-cell-independent and t-cell-dependent b-cell responses to exposed variant surface glycoprotein epitopes in trypanosome-infected mice. | the t-cell dependency of b-cell responses to variant surface glycoprotein (vsg) epitopes exposed in their native surface conformation on trypanosoma brucei rhodesiense clone loutat 1 was investigated. t-cell requirements were examined by analyses of gamma globulin preparations derived from trypanosome-infected balb/c nude (nu/nu) and thymus-intact (nu/+) mice. a radioimmunoassay was used to selectively quantitate antibody binding to native vsg 1 epitopes present on the surface of viable trypanos ... | 1990 | 1694824 |
| characterization of a cdna encoding a cysteine-rich cell surface protein located in the flagellar pocket of the protozoan trypanosoma brucei. | we have characterized a cdna encoding a cysteine-rich, acidic integral membrane protein (cram) of the parasitic protozoa trypanosoma brucei and trypanosoma equiperdum. unlike other membrane proteins of t. brucei, which are distributed throughout the cell surface, cram is concentrated in the flagellar pocket, an invagination of the cell surface of the trypanosome where endocytosis has been documented. accordingly, cram also locates to vesicles located underneath the pocket, providing evidence of ... | 1990 | 1697030 |
| the promoter for a variant surface glycoprotein gene expression site in trypanosoma brucei. | the variant-specific surface glycoprotein (vsg) gene 221 of trypanosoma brucei is transcribed as part of a 60 kb expression site (es). we have identified the promoter controlling this multigene transcription unit by the use of 221 chromosome-enriched dna libraries and vsg gene 221 expression site specific transcripts. the start of transcription was determined by hybridization and rnase protection analysis of nascent rna. the 5' ends of the major transcripts coming from the initiation region map ... | 1990 | 1697265 |
| effect of rna secondary structure and modified bases on the inhibition of trypanosomatid protein synthesis in cell free extracts by antisense oligodeoxynucleotides. | every messenger rna from leishmanias and trypanosomes has at its 5' end a conserved region termed the mini-exon sequence which, however, varies from species to species. in a systematic study mrnas from trypanosoma brucei, trypanosoma vivax, and leishmania enriettii were translated in cell-free extracts in the presence of oligodeoxynucleotides complementary to part of the mini-exon sequence. the affinity of the same oligonucleotides for target and non-target mrnas was determined by thermal elutio ... | 1990 | 1697674 |
| transcription of the heat shock 70 locus in trypanosoma brucei. | the 23-kb heat shock 70 locus of the protozoan parasite trypanosoma brucei encodes several tightly clustered genes. from 5' to 3', a cognate hsp70 gene (gene 1) (see preceding paper, lee et al.) is separated from a cluster of five identical hsp70 genes (genes 2-6) by about 6 kb of dna that encodes several rnas of unknown function. polycistronic transcripts could be detected in the tandem array of hsp70 genes 2-6 and the maturation of the hsp70 pre-mrnas involves addition of mini-exons on at leas ... | 1990 | 1697934 |
| trypanosoma brucei: constitutive activity of the vsg and procyclin gene promoters. | the variant surface glycoprotein (vsg) and procyclin are the major surface proteins of the bloodstream and procyclic stages, respectively, of trypanosoma brucei. the promoter regions of the vsg and procyclin gene transcription units could be mapped thanks to the specific enrichment of initial transcripts that occurs following uv irradiation. whereas the vsg gene is 45 kb distant from its promoter, procyclin genes are located immediately downstream. we show, by run-on assays on isolated nuclei an ... | 1990 | 1698609 |
| synchronous differentiation of trypanosoma brucei from bloodstream to procyclic forms in vitro. | the differentiation of mammalian stage trypanosoma brucei bloodstream forms comprising predominantly parasites of intermediate and stumpy morphology to the procyclic forms characteristic for the insect midgut stage was studied in vitro. differentiation of the cell population occurred synchronously as judged by the synthesis of the surface glycoprotein, procyclin, characteristic of the arising procyclic forms and the loss of the membrane-form variant surface glycoprotein, the coat protein of bloo ... | 1990 | 1698624 |
| rna editing--a novel genetic phenomenon? | 1990 | 1700474 | |
| sequence of the pcka gene of escherichia coli k-12: relevance to genetic and allosteric regulation and homology of e. coli phosphoenolpyruvate carboxykinase with the enzymes from trypanosoma brucei and saccharomyces cerevisiae. | the sequence of the pcka gene coding for phosphoenolpyruvate carboxykinase in escherichia coli k-12 and previous molecular weight determinations indicate that this allosteric enzyme is a monomer of mr 51,316. the protein is homologous to atp-dependent phosphoenolpyruvate carboxykinases from trypanosoma brucei and saccharomyces cerevisiae. a potential atp binding site was conserved in all three sequences. a potential binding site for the allosteric activator, calcium, identified in the e. coli en ... | 1990 | 1701430 |
| characterization of vsg gene expression site promoters and promoter-associated dna rearrangement events. | the expressed variant cell surface glycoprotein (vsg) gene of trypanosoma brucei is located at the 3' end of a large, telomeric, polycistronic transcription unit or expression site. we show that the region 45 kb upstream of the vsg gene, in the expression site on a 1.5-mb chromosome, contains at least two promoters that are arranged in tandem, directing the transcription of the expression site. dna rearrangement events occur specifically, at inactivation of the expression site, and these events ... | 1991 | 1708090 |
| conserved genes encode guide rnas in mitochondria of crithidia fasciculata. | rna editing is the post-transcriptional alteration of the nucleotide sequence of rna, which in trypanosome mitochondria is characterized by the insertion and deletion of uridine residues. it has recently been proposed that the information for the sequence alteration in leishmania tarentolae is provided by small guide (g) rnas encoded in the mitochondrial dna [blum et al. (1990) cell, 60, 189-198]. we are studying the mechanism of rna editing in the insect trypanosome crithidia fasciculata and re ... | 1991 | 1708723 |
| antigenic variation in trypanosoma brucei: a telomeric expression site for variant-specific surface glycoprotein genes with novel features. | african trypanosomes evade the immune response of their host by periodically changing their variant surface glycoprotein (vsg) coat. each coat is encoded by a separate vsg gene. expressed genes are in a telomeric expression site (es) and there are several sites in each trypanosome. to study the transcription control of vsg genes in trypanosoma brucei we have analyzed an es, called the dominant es (des), that readily switches off and on. the promoter area of the des is very similar to that of the ... | 1991 | 1709274 |
| maturation of polycistronic pre-mrna in trypanosoma brucei: analysis of trans splicing and poly(a) addition at nascent rna transcripts from the hsp70 locus. | numerous protein-coding genes of the protozoan trypanosoma brucei are arranged in tandem arrays that are transcribed polycistronically. the pre-mrna transcripts are processed by trans splicing, leading to the addition of a capped 39-nucleotide (nt) miniexon and by poly(a) addition. we wished to determine the order of the rna processing events at the hsp70 locus and address the potential occurrence of cotranscriptional rna processing. we determined the rate of transcriptional elongation at the hs ... | 1991 | 1710026 |
| distinct patterns of tyrosine phosphorylation during the life cycle of trypanosoma brucei. | regulation of tyrosine phosphorylation is a critical element in controlling growth and differentiation in higher eukaryotes. we have determined that the protozoan trypanosoma brucei, which diverged early in the eukaryotic lineage, possesses multiple proteins which react with a specific anti-phosphotyrosine antiserum. anti-phosphotyrosine immunoprecipitates of [32p]orthophosphate-labeled cells were shown to contain phosphotyrosine by two-dimensional electrophoresis. western analysis of cells from ... | 1991 | 1710035 |
| expression site-associated genes transcribed independently of variant surface glycoprotein genes in trypanosoma brucei. | expression site-associated genes (esags) of trypanosoma brucei are found upstream of variant surface glycoprotein (vsg) genes in bloodstream expression sites. there are at least 6 different esags in each of these expression sites, and each esag is repetitive in the genome. esags are believed to reside only in vsg expression sites and to be co-transcribed with the vsg gene from a common alpha-amanitin-insensitive promoter. our results show that this is not always true. the transcriptionally activ ... | 1991 | 1713298 |
| distinction of naive and memory bocd4 lymphocytes in calves with a monoclonal antibody, cc76, to a restricted determinant of the bovine leukocyte-common antigen, cd45. | a murine igg1 monoclonal antibody (mab), cc76, has been produced that, based on findings of the relative molecular mass of polypeptides that it recognized, staining of leukocytes in blood and tissues, and the biological properties of the t lymphocyte subpopulations with which it reacts, is considered to identify an isoform of the leukocyte common antigen (lca) family of molecules in cattle. the mab is more similar to human cd45r which detect products requiring the presence of the b exon within t ... | 1991 | 1716214 |
| trnas of trypanosoma brucei. unusual gene organization and mitochondrial importation. | in trypanosoma brucei the u snrna b gene (j. c. mottram, k. l. perry, p. m. lizardi, r. lührmann, n. agabian, and r. g. nelson (1989) mol. cell. biol. 9, 1212-1223) is very tightly linked with other small rna genes coding for trna(acgarg), trna(cuulys), and a approximately 275-nucleotide rna (rna x) of unknown function. a similar genomic organization is found at the u6 snrna locus, where the u6 gene is linked to trna(cguthr) and trna(guatyr) genes. the trna(lys) and trna(arg) genes are members o ... | 1991 | 1717447 |
| cycles of progressive realignment of grna with mrna in rna editing. | we characterized numerous partially edited nadh dehydrogenase 7 and atpase 6 cdnas. most of these have a stretch of incompletely edited sequence at the junction of mature and unedited sequences. the characteristics of the junctions suggest editing of sites multiple times and that editing within each junction does not proceed precisely 3' to 5'. analyses of grnas and corresponding junction sequences predict a series of progressively more stable, but incompletely base-paired, interactions in the j ... | 1991 | 1718605 |
| immunopathology of experimental african sleeping sickness: detection of cytokine mrna in the brains of trypanosoma brucei brucei-infected mice. | the immunopathology of trypanosoma brucei brucei in the central nervous system was studied by using an experimental model of chronic meningoencephalitis in outbred cd-1 mice. mice infected with t. b. brucei were treated with a subcurative dose of the trypanocidal compound diaminazine aceturate. these mice relapsed and were again drug treated. the brains were examined histologically and by immunocytochemistry to identify activated astrocytes. the polymerase chain reaction was used to detect cytok ... | 1991 | 1718878 |
| modification of trypanosoma brucei mitochondrial rrna by posttranscriptional 3' polyuridine tail formation. | trypanosoma brucei mitochondrial transcripts can be posttranscriptionally processed by uridine addition or deletion. with editing of mrnas, uridine addition and deletion create precisely altered reading frames. the addition of nonencoded uridines to mitochondrial guide rnas results in a less precise modification. although uridines are specifically added to the 3' termini, their number varies, which results in heterogeneous oligo(u) tails on guide rnas. in this paper, we show that the mitochondri ... | 1991 | 1719373 |
| trans splicing in trypanosomes requires methylation of the 5' end of the spliced leader rna. | trypanosoma brucei spliced leader (sl) rna contains an unusual cap 4 structure consisting of 7-methylguanosine linked to four modified nucleosides. during rna maturation, trans splicing transfers the first 39 nucleotides of the sl rna including the cap structure to the 5' end of all mrnas. here we show that exposure of permeable trypanosome cells to s-adenosyl-l-homocysteine inhibits methylation of the nucleosides adjacent to 7-methylguanosine of newly synthesized sl rna and prevents utilization ... | 1991 | 1719544 |
| calcium homeostasis in trypanosoma brucei. identification of a ph-sensitive non-mitochondrial calcium pool. | the objective of this study was to characterize mechanisms which maintain intracellular calcium homeostasis in bloodstream forms of trypanosoma brucei. the identification of homeostatic pathways is required to understand signal transduction in these organisms. the fluorescent probes fura-2, 2',7'-bis(carboxyethyl)-5(6)-carboxyfluorescein, and bisoxonal were used to measure intracellular calcium ([ca2+]i), intracellular ph (phi), and membrane potential, respectively. homeostatic pathways maintain ... | 1991 | 1722203 |
| the trypanosoma brucei cytoskeleton: ultrastructure and localization of microtubule-associated and spectrin-like proteins using quick-freeze, deep-etch, immunogold electron microscopy. | we have used a combination of quick-freezing/deep-etching and colloidal gold immunocytochemistry (i) to analyze the molecular organization of the microtubular membrane skeleton and the flagellum of trypanosoma brucei, and (ii) to localize two defined cytoskeletal proteins within these structures. the cell body of trypanosomatids is enveloped by a membrane skeleton consisting of a tightly packed array of microtubules which are closely associated with the cell membrane. the membrane-oriented face ... | 1991 | 1725491 |
| trypanosoma brucei brucei: antigenic stability of its ldl receptor and immunological cross-reactivity with the ldl receptor of the mammalian host. | the rapid growth of trypanosoma brucei brucei in the blood and tissue fluids of vertebrates requires the receptor-mediated endocytosis of ldl from the host (coppens et al. 1987; gillett and owen 1987) and is slowed by a monospecific rabbit antiserum against the purified ldl receptor of the parasite. we have used this antiserum in combination with several well-characterized antigenic variants (originating from stock 427: mitat 1.1a, 1.3a, 1.4a, 1.5a, 1.5d, 1.8b) to examine whether the ldl recepto ... | 1992 | 1730273 |
| extensive editing of both processed and preprocessed maxicircle cr6 transcripts in trypanosoma brucei. | transcripts from several genes encoded in the trypanosoma brucei maxicircle genome are altered by posttranscriptional uridine insertion and deletion through a process called rna editing. we find that transcripts from the cr6 gene are extensively edited by addition of 132 uridines and deletion of 28 uridines to produce a fully edited mrna 47% larger than unedited mrna. two open reading frames (orfs) and their initiation and termination codons are created by editing of cr6 mrna. both orfs specify ... | 1992 | 1730639 |
| characterization of an endopeptidase of trypanosoma brucei brucei. | a soluble 80-kda endopeptidase has been isolated from trypanosoma brucei brucei. the enzyme, which has a pi 5.1, is optimally active at about ph 8.2 and has apparent pka values of 6.0 and greater than or equal to 10. it is inhibited by the serine protease inhibitor diisopropylfluorophosphate and by the serine protease mechanism-based inhibitor 3,4-dichloroisocoumarin. unexpectedly, the enzyme is inhibited by the cysteine protease inhibitor benzyloxycarbonyl-leu-lys-chn2 but not by the related di ... | 1992 | 1731636 |
| mutual adjustment of glucose uptake and metabolism in trypanosoma brucei grown in a chemostat. | the mutual adjustment of glucose uptake and metabolism in the insect stage of the protozoan parasite trypanosoma brucei was studied. t. brucei was preadapted in the chemostat to conditions in which either glucose or proline served as the major carbon and energy source. cells were grown and adapted to either energy or non-energy limitation at a low dilution rate (0.5 day-1) or a high dilution rate (1 day-1). the cells were then used in short- to medium-term uptake experiments with d-[14c]glucose ... | 1992 | 1735718 |
| cysteine is an essential growth factor for trypanosoma brucei bloodstream forms. | a modified cystine-free minimum essential medium has been used to address the question whether cysteine is an essential growth factor for bloodstream form trypanosomes or if its reducing power is sufficient to support parasite growth in axenic culture. bloodstream-form trypanosomes, taken either from freshly isolated infected mouse blood or from logarithmically growing axenic cultures were transferred to a medium containing 20% dialysed foetal calf serum, 10 microm bathocuproine sulphonate and 2 ... | 1992 | 1741014 |
| trypanosoma brucei: peptide mapping of partially homologous variable surface glycoproteins. | antigenic variation in trypanosoma brucei is caused by amino acid sequence changes in a major surface glycoprotein. each trypanosome may contain between 100 and 1000 genes coding for this glycoprotein. some of these genes are members of partially homologous gene families. in addition, segments of different genes may combine to form 'hybrid' or 'mosaic' genes. thus, surface glycoproteins exist containing varying amounts of amino acid sequence homology. for investigations of molecular mechanisms o ... | 1991 | 1743853 |
| the trypanosoma brucei dna polymerase alpha core subunit gene is developmentally regulated and linked to a constitutively expressed open reading frame. | as an initial step towards the characterization of replicative dna polymerases of trypanosomes, we have cloned, sequenced and examined the expression of the trypanosoma (trypanozoon) brucei brucei gene that encodes the dna polymerase alpha catalytic core (pol alpha). the protein sequence contains the six conserved regions that have been recognized previously in eukaryotic and viral replicative dna polymerases. in addition, we have identified a seventh region which appears to be conserved primari ... | 1991 | 1754381 |
| the distribution of permeant ions demonstrates the presence of at least two distinct electrical gradients in bloodstream forms of trypanosoma brucei. | the distribution of 86rb+ and the radiolabelled lipophilic cation [3h]methyltriphenylphosphonium (meph3p+) was used to investigate the membrane potentials that exist in bloodstream forms of trypanosoma brucei. even after correction for binding to cellular constituents, the accumulation of meph3p+ was approximately tenfold greater than the accumulation of rb+ under resting conditions. the addition of low concentrations of carbonylcyanide p-trifluoromethoxyphenylhydrazone or valinomycin reduced th ... | 1991 | 1761044 |
| high homology between variant surface glycoprotein gene expression sites of trypanosoma brucei and trypanosoma gambiense. | the antat 11.17 variant surface glycoprotein (vsg) is synthesized in both metacyclic and bloodstream forms of trypanosoma gambiense. we have characterized the antat 11.17 gene, and analyzed its expression site (es) in the bloodstream form by southern and northern blotting with probes from the trypanosoma brucei antat 1.3a vsg es, and by run-on transcription. the antat 11.17 es is located at the end of a 700-kb chromosome. it appears to contain all the genes (esags, for expression site-associated ... | 1991 | 1762631 |
| porcine trypanosomosis in nigeria: infections in local and exotic pigs in the nsukka area of anambra state. | a twelve-month survey in three local government areas (lga) in nsukka zone, anambra state, nigeria revealed that out of 150 local and exotic breeds of pig examined, 46 (30.7%) were infected with trypanosomes. both single and mixed infections of trypanosoma brucei and t. congolense were observed. however, t. brucei was the predominant trypanosome encountered. the husbandry system in practice was the most significant factor influencing the prevalence of trypanosomes in the pigs. in addition signif ... | 1991 | 1763434 |
| trypanosomiasis in different breeds of cattle from benin. | blood of different breeds of cattle, namely lagune from the atlantic province, borgou and borgou x zebu from the borgou province, and somba and zebu from the atacora province of benin, were examined for trypanosome infection. thick and thin blood smears for trypanosomes, the card agglutination test (catt), indirect immunofluorescent antibody test (ifat) and trypanolytic test for antibodies to trypanosomes were used. trypanosomes were detected in 19.3% (range 9.8-31.4%) of animals by examination ... | 1991 | 1763478 |
| control of tsetse and trypanosomiasis transmission in uganda by applications of lambda-cyhalothrin. | the pyrethroid insecticide lambda-cyhalothrin was evaluated in field trials against glossina f.fuscipes and sleeping sickness transmission in iyolwa sub-county, tororo district, uganda. the insecticide was applied selectively to the resting-sites of tsetse, by bush-spraying, using 10% wettable powder (10wp) formulation at an application rate of 11.6 g a.i./ha over an area of 28 km2, or by a 2% electrodyn formulation (2ed) applied at 0.9 g a.i./ha over 30 km2. in a third trial area of 32 km2, 215 ... | 1991 | 1768891 |
| lectin and peritrophic membrane development in the gut of glossina m.morsitans and a discussion of their role in protecting the fly against trypanosome infection. | newly emerged glossina m.morsitans westwood tsetse flies lack a peritrophic membrane which develops to fully line the midgut after c. 80-90 h. midgut lectins are mainly associated with the peritrophic membrane. lectin levels in the blood-free gut of adult flies rise slowly up to 8 days and then rapidly to at least 14 days post-eclosion (when the last of our recordings was made). despite starving flies for 4 days prior to the agglutination assay, gut lectin levels in older flies are 100-200 times ... | 1991 | 1773127 |
| fever, leukopenia, and a cutaneous lesion in a man who had recently traveled in africa. | 1991 | 1775846 | |
| treatment of experimental trypanosomiasis in pigs. | the therapeutic activity of difluoromethylornithine (dfmo), diminazene aceturate (berenil) and their combination against chronic trypanosomiasis was investigated in experimental trypanosoma brucei brucei infections of growing pigs. dfmo (300 mg/kg/day orally for 10 days), diminazene aceturate (7 mg/kg in single intramuscular injection) and a combination of the two agents at the above dosages produced varied periods of aparasitaemia in the treated pigs. relapse parasitaemia occurred in all treatm ... | 1991 | 1777799 |
| subcellular distribution of trypanothione reductase in bloodstream and procyclic forms of trypanosoma brucei. | 1991 | 1779986 | |
| the effects of genetic exchange on variable antigen expression in trypanosoma brucei. | the inheritance of variant surface antigens in trypanosoma brucei has been determined by identifying variable antigen types (vats) in each of two cloned parental stocks and then examining the presence and abundance of these vats in hybrid progeny produced when these stocks undergo genetic exchange during co-transmission through tsetse flies. nine vats have been identified from the repertoire of the parental stock stib 247l and 5 vats have been identified from the parental stock stib 386aa; the i ... | 1991 | 1780175 |
| trypanosoma brucei brucei: differences in the trypanocidal activity of human plasma and its relationship to the level of high density lipoproteins. | although high density lipoprotein (hdl) particles purified from human serum by ultracentrifugation are known to lyse trypanosoma brucei brucei, it is unclear whether individual differences in the trypanocidal activity of human serum reflect changes in the concentration of hdl per se. in the present study, trypanolytic activity, whether assessed in vitro or in vivo, was greater with plasma from normal healthy individuals than with plasma from patients with various hepatic diseases and associated ... | 1991 | 1780989 |
| transferrin receptor, antigenic variation and the prospect of a trypanosome vaccine. | 1991 | 1781026 | |
| evolutionary aspects of gpi metabolism in kinetoplastid parasites. | there is a growing, but still very patchy, data base of gpi structure, biosynthesis and function. in this article we speculate freely on the function of gpi anchors, and the origins of gpi-related molecules, primarily with reference to the protozoan parasites trypanosoma brucei and the leishmania. the views expressed draw on fairly wild extrapolations and some will, no doubt, not stand the tests of time. several of the hypotheses presented should therefore be taken with a pinch of salt, some lem ... | 1991 | 1782666 |
| transferrin is a growth factor for the bloodstream form of trypanosoma brucei. | a method for the selective depletion of transferrin from bovine serum is presented. bloodstream forms of trypanosoma brucei cannot grow in medium containing transferrin-deficient serum, whereas reconstitution with transferrin restores normal growth. we conclude that transferrin is an essential growth factor for the mammalian stage of the parasite. | 1991 | 1792224 |
| preparation of phenylalanine-deuterated, and totally 15n-enriched, calmodulins from trypanosoma brucei, and its application to drug binding studies. | 1991 | 1794549 | |
| chemotherapy of cns-trypanosomiasis: combination chemotherapy with a 5-nitroimidazole (mk 436), an arsenical (cymelarsan) and suramin. | a detailed study of the combined effect of suramin, mk 436 (5-nitroimidazole) and cymelarsan (melaminylthioarsenate) was investigated in the murine cns-trypanosomiasis model. using a combination of cymelarsan and mk 436 without preliminary suramin, complete cures were obtained with a 2 day treatment of 15.0 mg/kg mk 436 and 5.0 mg/kg cymelarsan. if the mk 436 was reduced to 10 mg/kg then 4 consecutive daily treatments were required. if the cymelarsan was reduced to 2.5 mg/kg either a 3 day treat ... | 1991 | 1801135 |
| laboratory diagnosis of trypanosomiasis. | although african trypanosomiasis, or sleeping sickness, in humans was largely under control approximately 30 years ago, today most of the historical foci show an alarming increase in the number of cases, particularly those in east and central africa. this article describes the epidemiology, clinical features, and diagnostic techniques for both african and american trypanosomiasis. | 1991 | 1802527 |
| a soluble fumarate reductase in trypanosoma brucei procyclic trypomastigotes. | the enzyme nadh-fumarate reductase associated with the membrane fraction of trypanosoma brucei procyclic trypomastigotes, can be solubilized by more than 50% when increasing the ionic strength to the equivalent of 150 mm kcl. the apparent kms for nadh (125 microm) and fumarate (50 microm) remain close to those previously reported for the membrane-bound form of this enzyme. other electron acceptors (i.e. oxygen or cytochrome c) appear to accept electrons in the absence of fumarate (km for cytochr ... | 1991 | 1818198 |
| pig trypanosomiasis: comparative anaemia and histopathology of lymphoid organs. | anaemia with characteristic clinical symptoms, haematological changes and histopathology of lymphoid organs, was observed following experimental infection of pig with pathogenic species of trypanosoma brucei brucei and trypanosoma congolense, the former being more virulent than the latter. mean incubation periods were 4 and 7 days, and generalized fluctuating levels of parasitaemia and pyrexia without mortality were observed. other symptoms included hyperaemia, petechial haemorrhages leading to ... | 1991 | 1824133 |
| pathogenicity of trypanosoma brucei brucei in experimentally infected pigs. | an experimental infection of 4-to 5-month old pigs with a stock of trypanosoma brucei brucei resulted in a high parasitaemia, anorexia, pyrexia and a decline in the packed cell volume by one third. nervous sign of circling and wobbling of the hind legs occurred in one of the pigs which at necropsy revealed a very severe meningo-encephalitis and the presence of trypanosomes in the brain. these results confirm that t. b. brucei might cause a severe disease in pigs. | 1991 | 1824136 |
| a new u6 small nuclear ribonucleoprotein-specific protein conserved between cis- and trans-splicing systems. | spliceosomal u6 small nuclear rna (snrna) plays a central role in the pre-mrna splicing mechanism and is highly conserved throughout evolution. previously, a sequence element essential for both capping and cytoplasmic-nuclear transport of u6 snrna was mapped in the 5'-terminal domain of u6 snrna. we have identified a protein in cytoplasmic extracts of mammalian and trypanosoma brucei cells that binds specifically to this u6 snrna element. competition studies with mutant and heterologous rnas dem ... | 1991 | 1826044 |
| maintenance of internal ph and an electrochemical gradient in trypanosoma brucei. | the internal ph value (phi) of the long-slender bloodstream form of trypanosoma brucei was estimated from the distribution of 14c-labeled 5,5-dimethyl-2,4-oxazolidinedione or 14c-labeled methyl amine between the intracellular space of the cells and the medium. the phi of t. brucei remained relatively constant at 7.0-7.2 throughout an extracellular ph (pho) range of 6.0-8.0. the maintenance of an internal ph more acidic than the environment appears to be a unique feature. preincubation of t. bruc ... | 1991 | 1826655 |
| defective glycosyl phosphatidylinositol biosynthesis in extracts of three thy-1 negative lymphoma cell mutants. | the glycosyl phosphatidylinositol (gpi) anchors that attach certain proteins to membranes are preassembled by sequential addition of glycan components to phosphatidylinositol (pi) before being transferred to nascent polypeptide. a cell-free system consisting of trypanosome membranes has been reported to catalyze gpi biosynthesis (masterson, w. j., doering, t. l., hart, g. w., and englund, p. t. (1989) cell 56, 793-800; menon, a. k., schwarz, r. t., mayor, s., and cross, g. a. m. (1990) j. biol. ... | 1991 | 1828068 |
| transfer of glycosyl-phosphatidylinositol membrane anchors to polypeptide acceptors in a cell-free system. | glycosylinositol phospholipid (gpi) membrane anchors are the sole means of membrane attachment of a large number of cell surface proteins, including the variant surface glycoproteins (vsgs) of the parasitic protozoan, trypanosoma brucei. biosynthetic data suggest that gpi-anchored proteins are synthesized with carboxy-terminal extensions that are immediately replaced by gpi, suggesting the existence of preformed gpi species available for transfer to the nascent protein in the er. candidate precu ... | 1991 | 1828808 |
| an analog of myristic acid with selective toxicity for african trypanosomes. | trypanosoma brucei, the protozoan parasite responsible for african sleeping sickness, evades the host immune response through the process of antigenic variation. the variant antigen, known as the variant surface glycoprotein (vsg), is anchored to the cell surface by a glycosyl phosphatidylinositol (gpi) structure that contains myristate (n-tetradecanoate) as its only fatty acid component. the utilization of heteroatom-containing analogs of myristate was studied both in a cell-free system and in ... | 1991 | 1829548 |
| mannosamine, a novel inhibitor of glycosylphosphatidylinositol incorporation into proteins. | mannosamine (2-amino-2-deoxy d-mannose) is shown here to block the incorporation of glycosylphosphatidylinositol (gpi) into gpi-anchored proteins. the amino sugar drastically reduced the surface expression of a recombinant gpi-anchored protein in polarized mdck cells, converted this apical membrane-bound protein to an unpolarized secretory product and blocked the expression of endogenous gpi-anchored proteins. furthermore, it specifically inhibited the incorporation of [3h]ethanolamine (a gpi co ... | 1991 | 1829673 |
| phenylmethanesulphonyl fluoride inhibits gpi anchor biosynthesis in the african trypanosome. | a wide variety of eukaryotic membrane proteins are anchored to the outside of cells by covalent linkage to glycosyl phosphatidylinositol (gpi). one of the best characterized examples is the variant surface glycoprotein (vsg) of the protozoan parasite, trypanosoma brucei. the structure of the gpi precursor is ethanolamine-po4-man alpha 1-2man alpha 1-6man alpha 1-4glcnh2-pi; the phosphoethanolamine moiety forms an amide linkage to the vsg polypeptide alpha-cooh group during its attachment to prot ... | 1991 | 1829674 |
| evolutionary conservation of a microbody targeting signal that targets proteins to peroxisomes, glyoxysomes, and glycosomes. | peroxisomes, glyoxysomes, glycosomes, and hydrogenosomes have each been classified as microbodies, i.e., subcellular organelles with an electron-dense matrix that is bound by a single membrane. we investigated whether these organelles might share a common evolutionary origin by asking if targeting signals used for translocation of proteins into these microbodies are related. a peroxisomal targeting signal (pts) consisting of the cooh-terminal tripeptide serine-lysine-leucine-cooh has been identi ... | 1991 | 1831458 |
| the mitochondrial atp synthase of trypanosoma brucei: developmental regulation through the life cycle. | the mitochondrial h(+)-atpase of the parasitic protozoan trypanosoma brucei is shown to be developmentally regulated through the t. brucei life cycle as has been shown for components of the mitochondrial electron transport chain. we have substantiated our results by assaying not only for oligomycin-sensitive atpase activity but also by determining the level of atp synthetic activity. these results show that the level of atpase present in the procyclic form of t. brucei is increased by at least t ... | 1991 | 1832842 |
| structure and transcription of a p-atpase gene from trypanosoma brucei. | a putative atpase gene was cloned from trypanosoma brucei genomic dna. the length of the gene open reading frame is 3,033 bp, predicting a protein of about 110 kda. the sequence of this protein shares 10 blocks of homology with other eukaryotic atpases, including the putative phosphorylation site characteristic of p-atpases. its hydropathy profile reveals 8-10 potential membrane-spanning regions. while the amino acid sequence of the t. brucei atpase shows only 25% overall homology with its count ... | 1991 | 1833643 |
| affinity purification of trypanosoma brucei small nuclear ribonucleoproteins reveals common and specific protein components. | we have developed a procedure for the affinity purification of small nuclear ribonucleoproteins (snrnps) of trypanosoma brucei (u2 and u4/u6 snrnps), which are essential for trans splicing. each of these snrnps can be specifically and efficiently selected from t. brucei extracts through biotinylated antisense 2'-o-methylated rna oligonucleotides immobilized on streptavidin-agarose. protein analysis revealed a set of five low molecular weight polypeptides common to the u2 and u4/u6 snrnps and the ... | 1991 | 1833773 |
| production of monoclonal antibodies against the purified glycosylphosphatidylinositol anchor of the variant surface glycoprotein from trypanosoma brucei brucei. | the glycosylphosphatidylinositol anchor (gpi) from the membrane form variant surface glycoprotein (mfvsg) of trypanosoma brucei brucei was isolated and identified after radioactive labeling with [3h]myristic acid, by immunostaining on hptlc with a polyclonal antibody directed against mfvsg and by negative ion laser desorption and fast atom bombardment mass spectrometry of the gpi anchor before and after peracetylation. for the production of monoclonal antibodies the purified gpi molecule was inc ... | 1991 | 1834019 |
| differential expression of the oligomycin-sensitive atpase in bloodstream forms of trypanosoma brucei brucei. | we report the differential expression of the oligomycin-sensitive mitochondrial atpase in pleomorphic bloodstream forms of trypanosoma brucei brucei as observed with enzymatic assays and electron microscope histochemistry. as the cells differentiate from long slender to short stumpy forms, total specific activity of the mitochondrial atpase in a crude mitochondrial fraction doubles and the oligomycin-sensitive specific activity increases 5-fold. upon in vitro differentiation to procyclic forms, ... | 1991 | 1838138 |
| the biology of the glycosylphosphatidylinositol-specific phospholipase c of trypanosoma brucei. | 1991 | 1838304 | |
| anatomy of the parp gene promoter of trypanosoma brucei. | while growing in the tsetse fly, trypanosoma brucei expresses a major surface glycoprotein, the procyclic acidic repetitive protein (parp). the parp genes are transcribed by an alpha-amanitin-resistant rna polymerase. we have determined the sequence requirements for parp promoter activity. studies of rna produced from input dna in transiently transfected trypanosomes indicate that the rna is correctly processed by trans-splicing and polyadenylation. deletion analyses show that 330 bp are suffici ... | 1991 | 1840521 |
| [vectorial capacity of glossina palpalis gambiensis (bobo dioulasso) for trypanosoma brucei brucei eatro 1125]. | a total of 440 teneral glossina palpalis gambiensis received one single bloodmeal on a guinea pig infected chronically with trypanosoma brucei brucei eatro 1125. metacyclic infections were present in 11.29% of the flies, in 2.32% infections were limited to procyclical stages. no significant difference in vectorial capacity was observed between male and female flies, the level of metacyclic infections being 13.19% in the former and 9.55% in the latter. the parasitaemia level, the percentage of st ... | 1991 | 1843825 |
| dl-alpha-difluoromethylornithine (dfmo)-berenil combination: therapeutic and prophylactic activity against trypanosoma brucei brucei infection in mice. | the therapeutic and prophylactic activity of difluoromethylornithine (dfmo) (2% in drinking water for 4 days) and berenil (7 mg/kg live weight intraperitoneally) combination was investigated in mice infected with trypanosoma brucei brucei. using a previously described mouse model of the african trypanosomosis of the central nervous system, it was demonstrated that the combination was curative and acted synergistically. however, if used prophylactically it had no advantage over berenil alone. | 1991 | 1843826 |
| a transferrin-binding protein of trypanosoma brucei is encoded by one of the genes in the variant surface glycoprotein gene expression site. | a transferrin-binding protein (tfbp) with an apparent molecular weight of 42 kd was purified from detergent-soluble membrane proteins of bloodstream forms of trypanosoma brucei. the protein is not expressed in the insect-borne stage of the parasite's life-cycle. purified tfbp can be converted from an amphiphilic to a hydrophilic form by cleavage with t.brucei glycosylphosphatidylinositol (gpi)-specific phospholipase c, demonstrating that the c-terminus is modified by a gpi-membrane anchor. the t ... | 1991 | 1845367 |
| differential sensitivity of trypanosoma brucei rhodesiense isolates to in vitro lysis by arsenicals. | clinical isolates of trypanosoma brucei rhodesiense, which were resistant to arsenical drugs in murine infections, were examined for resistance in vitro. a rapid lysis assay was developed which was able to predict in vivo sensitivity to melarsoprol (mel b, arsobal) and melarsen oxide. the assay was based on the finding that long slender bloodforms of drug-sensitive isolates would lyse in the presence of arsenicals upon incubation in heat-inactivated fetal bovine serum. on the basis of plots of d ... | 1991 | 1849084 |
| developmental variation of glycosylphosphatidylinositol membrane anchors in trypanosoma brucei. identification of a candidate biosynthetic precursor of the glycosylphosphatidylinositol anchor of the major procyclic stage surface glycoprotein. | the major surface antigen of the mammalian bloodstream form of trypanosoma brucei, the variant surface glycoprotein (vsg), is attached to the cell membrane by a glycosylphosphatidylinositol (gpi) anchor. the vsg anchor is susceptible to phosphatidylinositol-specific phospholipase c (pi-plc). candidate precursor glycolipids, p2 and p3, which are pi-plc-sensitive and -resistant respectively, have been characterized in the bloodstream stage. in the insect midgut stage, the major surface glycoprotei ... | 1991 | 1850744 |
| a phosphoglycerate kinase-like molecule localized to glycosomal microbodies: evidence that the topogenic signal is not at the c-terminus. | the phosphoglycerate kinase (pgk) gene complex of trypanosoma brucei contains three tandemly linked related genes. one gene encodes a cytoplasmic pgk, while another encodes a pgk isozyme localized to glycosomal microbodies. in this communication, we report that the third gene in this complex encodes a 56-kda molecule which is also localized to the glycosomal core. dna sequence analysis indicates that this gene contains multiple substitutions and a large insertion in the amino domain, but that it ... | 1991 | 1852165 |