| purification and regulatory properties of phosphofructokinase from trypanosoma (trypanozoon) brucei brucei. | phosphofructokinase (ec 2.7.1.11) from trypanosoma (trypanozoon) brucei brucei was purified to homogeneity by using a three-step procedure that may be performed within 1 day. proteolysis, which removes a fragment of mr approx. 2000, may occur during the purification, but this can be prevented by including antipain, an inhibitor of cysteine proteinases, in the buffers during the purification. the subunits of the enzyme appear to be identical in size, with an mr of 49 000. the mr of the native enz ... | 1985 | 3158309 |
| a high affinity ca2+-dependent atpase in the surface membrane of the bloodstream stage of trypanosoma rhodesiense. | addition of ca2+ (0.01-1 mm) to a standard trypanosoma rhodesiense mg2+-atpase assay failed to elicit any increase in activity. however, in the absence of externally added mg2+ and using calcium-egta or calcium-cdta to precisely maintain free metal ion concentration, it was possible to measure a specific ca2+-atpase. cell fractionation studies revealed this atpase to be predominantly associated with subcellular particles having an equilibrium density of 1.22 g cm-3 and identified as surface memb ... | 1985 | 3159962 |
| trypanosoma brucei brucei: variability in the association of some variant surface glycoproteins. | in our isolation procedure, the surface antigens of the variants antat 1.1 and 1.10 (trypanosoma brucei brucei) are essentially obtained as a disulfide-linked dimer while the antat 1.8 surface antigen is found as a mixture of monomer and disulfide-linked dimer. this observation may be related to the localization of the cysteine residues in the protein sequences. in the purification procedure using concanavalin-a sepharose chromatography, besides the vsg elution by methyl-alpha-d-mannopyranoside, ... | 1988 | 3169201 |
| species-specific dna probes for the identification of african trypanosomes in tsetse flies. | we have obtained 5 specific dna probes for african trypanosomes of the subgenera trypanozoon and nannomonas. each probe consists of one repeat unit of the major repetitive dna (satellite dna) of each species or intra-specific group. one probe hybridized with all members of subgenus trypanozoon (except t. equiperdum which was not tested). in subgenus nannomonas, one probe recognized t. simiae, but 3 probes were needed to identify all stocks of t. congolense available. each of the 3 latter probes ... | 1988 | 3174239 |
| structure and sequence of the gene for the largest subunit of trypanosomal rna polymerase iii. | as the first step in the analysis of the transcription process in the african trypanosome, trypanosoma brucei, we have started to characterise the trypanosomal rna polymerases. we have previously described the gene encoding the largest subunit of rna polymerase ii and found that two almost identical rna polymerase ii genes are encoded within the genome of t. brucei. here we present the identification, cloning and sequence analysis of the gene encoding the largest subunit of rna polymerase iii. t ... | 1988 | 3174432 |
| effect of ivermectin and isometamidium chloride on glossina palpalis palpalis (diptera: glossinidae). | | 1988 | 3178326 |
| the sheep (ovis aries) as an experimental model for african trypanosomiasis. i. clinical study. | sheep were used as an experimental model to study trypanosomiasis. twelve animals were infected with trypanosoma brucei brucei, and the clinical evolution of the disease in the sheep corresponded closely to that described in human patients. the main clinical signs of the experimental infection were hyperthermia, anaemia, loss of weight and behavioural disturbances. death occurred in all cases after a mean time of 75 days. trypanosomes were detected in blood films nine to 15 days after inoculatio ... | 1988 | 3178335 |
| the sheep (ovis aries) as an experimental model for african trypanosomiasis. ii. biological study. | sheep that have been experimentally infected with a strain of trypanosoma brucei brucei reproduce the clinical symptomatology of human african trypanosomiasis. we measured two biochemical parameters which are altered during the infection; total serum and cerebrospinal fluid (csf) proteins, and the time of appearance and levels of igm in both serum and csf. serum protein levels were considerably raised (up to 90 gl-1), although in csf the levels were always less than 1 gl-1. the ratio of serum al ... | 1988 | 3178336 |
| regulation of variant surface glycoprotein synthesis in trypanosoma brucei. | | 1988 | 3181611 |
| the glycosylphosphatidylinositol membrane anchor of trypanosoma brucei variant surface glycoprotein. | | 1988 | 3181613 |
| crystallization of amino-terminal domains and domain fragments of variant surface glycoproteins from trypanosoma brucei brucei. | crystals were produced from variant surface glycoproteins (vsg) of trypanosoma brucei brucei antigenic variants mitat 1.2, 1.6, and iltat 1.22, 1.23, 1.24, 1.25, and 1.26. purified vsgs had molecular weights from 60,000 to 68,000 on sodium dodecyl sulfate-polyacrylamide gels, whereas the crystals obtained were composed of polypeptides of approximate mr 40,000-50,000. amino-terminal amino acid sequences determined from the crystallized vsgs were identical to sequences obtained from the respective ... | 1988 | 3182831 |
| biosynthesis of a variant surface glycoprotein of trypanosoma brucei. processing of the glycolipid membrane anchor and n-linked oligosaccharides. | the variant surface glycoprotein (vsg) of the iltat 1.3 variant of trypanosoma brucei has two asparagine-linked glycan moieties, as well as a phosphatidylinositol glycan membrane anchor. we have investigated the structure and processing of each of these oligosaccharides through analysis of the intact protein and of glycopeptides. processing has been examined by comparing glycan structures purified from an immature intracellular form (58 kda) of vsg with those of the mature form (59 kda) found on ... | 1988 | 3182868 |
| ribosome-inactivating proteins from plants inhibit ribosome activity of trypanosoma and leishmania. | ribosomes from trypanosoma brucei rhodesiense and from leishmania infantum were isolated and optimal conditions for in vitro translation were established. the effect of ribosome-inactivating proteins extracted from several plants was then assessed in order to identify those suitable for the preparation of immunotoxins against these organisms. ribosomes from both species were inactivated by some ribosome-inactivating proteins (dianthins, saporins, pokeweed antiviral proteins, and the ribosome-ina ... | 1988 | 3183997 |
| polymorphism in the procyclic acidic repetitive protein gene family of trypanosoma brucei. | the expression of procyclic acidic repetitive protein (parp) by trypanosoma brucei is strongly induced during the transition of bloodstream form to cultured procyclic trypomastigotes in vitro. the membrane-associated protein is distinguished by a central domain consisting of tandemly repeated glutamate-proline dipeptides. the trypanosome genome contains eight parp genes, at least four of which are expressed. a minimum of four distinct parp mrna species comprises two classes of parp mrna, based u ... | 1988 | 3185541 |
| nucleoside analysis of dna from trypanosoma brucei and trypanosoma equiperdum. | we have digested trypanosome dna with a combination of pancreatic dnase i, nuclease p1 and bovine alkaline phosphatase and fractionated the resulting nucleosides on a supelcosil lc-18-s column by high pressure liquid chromatography. we find less than 0.1% unusual nucleosides, both in trypanosoma brucei and in a trypanosoma equiperdum stock, in contrast to a previous report of an unusual nucleoside replacing dc at 1.3% of total nucleosides in t. equiperdum. our results agree with previous suggest ... | 1988 | 3185618 |
| purification in a single step and kinetic characterization of the pyruvate kinase of trypanosoma brucei. | the pyruvate kinase of trypanosoma brucei can be purified to homogeneity in one step by affinity elution from a phosphocellulose column with the substrate phosphoenolpyruvate (pep) and the allosteric activator fructose-2,6-diphosphate (fdp). the purified enzyme has a specific activity of 175 mumol min-1 (mg protein)-1 and a subunit molecular mass of 59 kda as judged by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. kinetic studies of the pure enzyme show that an increase in the pep c ... | 1988 | 3185619 |
| structure and expression of the hsp 70 gene family of leishmania major. | the parasitic protozoan leishmania major differentiates in vitro, from the insect-adapted promastigote to the mammalian infective amastigote, in response to a temperature shift from 25 degrees c to 37 degrees c. we studied the genes encoding 70 kilodalton heat shock proteins (hsp 70 genes) in leishmania substocks, which vary in their capability to differentiate. in total, four hsp 70 genes are arranged in tandem with intergenic regions of about 380 bp. these hsp 70 genes are 89% conserved at the ... | 1988 | 3186441 |
| physical identification of branched intron side-products of splicing in trypanosoma brucei. | every mrna in trypanosomes consists of two exons, a common 5' capped mini-exon or spliced leader and a coding-exon. all evidence suggests that the exons are joined by trans-splicing of two individual precursor rnas, the mini-exon donor rna or spliced leader precursor rna (medrna) and the pre-mrna. we studied intermediates of the splicing reaction using denaturing two-dimensional page and structurally identified a group of small (approximately 180-300 nt) non-polyadenylated, y-shaped branched rna ... | 1988 | 3191913 |
| trypanosoma brucei rhodesiense: effect of immunosuppression on the efficacy of melarsoprol treatment of infected mice. | | 1988 | 3191962 |
| loss of variable antigen during transformation of trypanosoma brucei rhodesiense from bloodstream to procyclic forms in the tsetse fly. | a pleomorphic line of trypanosoma brucei rhodesiense expressing a single variable antigen was used to quantify the rate of loss of the surface coat from bloodstream forms transforming to procyclics in the tsetse fly, glossina morsitans, and in in vitro culture. loss of variable antigen occurred at similar rates in the crop and anterior portion of the midgut of tsetse flies and in in vitro culture, but in the posterior portion of the fly midgut it occurred 2-3 times faster. the posterior portion ... | 1988 | 3194363 |
| cdna encoding the glycosyl-phosphatidylinositol-specific phospholipase c of trypanosoma brucei. | vsg lipase of trypanosoma brucei specifically cleaves the glycosyl-phosphatidylinositol membrane anchor of the trypanosome variant surface glycoprotein (vsg), releasing this protein from the plasma membrane. it also cleaves similar membrane anchors on some mammalian proteins. vsg lipase may play a role in processes such as parasite differentiation or antigenic variation. we describe here the cloning and sequencing of a cdna encoding vsg lipase from t. brucei. | 1988 | 3194399 |
| comparative study on the susceptibility of different glossina species to trypanosoma brucei brucei infection. | teneral glossina morsitans centralis, g. austeni, g. palpalis palpalis, g. p. gambiensis, g. fuscipes fuscipes, g. tachinoides and g. brevipalpis from laboratory-bred colonies, were allowed to feed simultaneously for 34 days on the flanks of ten goats infected with trypanosoma brucei brucei isolated in tanzania or in nigeria, and then the tsetse were dissected. the seven tsetse species and subspecies showed salivary glands infections over the range of 0% to 40.4%. survival of the tanzanian and n ... | 1988 | 3194664 |
| degeneration of serotonin-specific neurons in the brain in experimental trypanosoma brucei infection. | ormerod and hussein (1986) have shown that an intracellular stage of trypanosoma brucei rhodesiense causes the destruction of ependymal cells lining the ventricles of the brain. the ventricular ependymal cells are intimately associated with a plexus of nerves that react specifically with monoclonal antibody raised against serotonin. we have shown that in areas where the ependyma is damaged, the supraependymal plexus also undergoes destruction and that retrograde degeneration of the neuron as far ... | 1988 | 3197244 |
| [early auditory evoked potentials in normal sheep and in sheep with trypanosomiasis]. | in human and animal clinics, the early auditory potential has been used for a long time in the detection of lesions through the internal auditory way in the cerebral trunk. the aim of this work tries to determine if this non invasive test is apt to show up and to follow the evolution of lesions at the level of auditory way in the cerebral trunk of sheep with trypanosomiasis. according to the human technic, the list of the early auditory potential was realized against ten healthy sheep and ten sh ... | 1988 | 3197246 |
| evidence of blood cerebrospinal fluid barrier permeability impairment in trypanosoma rhodesiense infection in vervet monkeys. | blood-cerebrospinal fluid (csf) barrier damage in 11 vervet monkeys was estimated before infection and during the early and late phases of trypanosoma rhodesiense disease, using the method given by tibbling, link and ohman (1977). of the 11, only one monkey showed signs of barrier impairment that ranged from a slight (12.6) to total barrier impairment (285); the latter occurring just before the height of clinical encephalitis. the barrier reverted to normal after melarsoprol treatment at 1.8 mg/ ... | 1988 | 3197248 |
| [complement: a sign of infestation of sheep by trypanosoma brucei brucei in an experimental model: its evolution following treatment]. | broad variations in complement levels are seen during the course of many infectious diseases, particularly human and animal african trypanosomiasis. in this study, sheep complement is measured by means of its haemolytic activity expressed in 50% haemolytic complement units per ml (hcu50/ml). in healthy sheep, the average value is 23.3 hcu50/ml. complement levels dramatically decrease five days after subcutaneous inoculation of trypanosoma brucei brucei and remain undetectable until death of non ... | 1988 | 3197249 |
| [treatment of experimental trypanosomiasis caused by trypanosoma brucei brucei in sheep: study of the minimum active dose of melarsoprol]. | trypanosoma brucei brucei experimentally infected sheep with central nervous system involvement were treated with melarsoprol (arsobal, specia, france). the purpose was to determine minimum efficiency concentrations of this drug. eight sheep divided in four groups of two animals were treated intravenously for 3 days with the following respective dosages: 1.8, 0.9, 0.45 and 0.225 mg/kg/d. after a year of observation, efficient dosages were 1.8 and 0.9 mg/kg/d. the experimentation suggests the pos ... | 1988 | 3197250 |
| [a new series of antiparasitic organic arsenicals: the spiroarsoranes. experimental trypanocidal activity]. | arsenical compounds are the main therapeutic way, effective in the neurological phase of trypanosomiasis. unfortunately, their important toxicity prevents their easy administration. structural cyclization of arsonic acid derivatives has led to a class of non-toxic compounds: spiroarsoranes. a 47 compound primary screening on an in vivo murine model of trypanosoma brucei brucei resulted in the isolation of a very effective derivative after a single subcutaneous injection of 30 mg.kg-1 body weight ... | 1988 | 3197253 |
| [treatment of experimental trypanosomiasis of sheep caused by trypanosoma brucei brucei: efficacy of ro 15-0216 (a 2-nitroimidazole derivative)]. | an experiment was carried out on treatment of trypanosoma brucei brucei experimentally infected sheep with central nervous system involvement with a 2-nitroimidazole derivative: ro 15-0216 (hoffmann la roche & co ltd, basel, switzerland). after a single intramuscularly or intravenously administration (25 or 50 mg/kg) of this compound in healthy sheep, levels of more than 1 microgram/ml corresponding to trypanocidal concentrations are detected in both blood and cerebrospinal fluid. however, becau ... | 1988 | 3197255 |
| [the fatty acids of trypanosoma brucei brucei. a comparative study with those of t. b. rhodesiense and t. b. gambiense]. | total lipid extracts from trypanosoma brucei brucei (t.b.b.), trypanosoma brucei gambiense (t.b.g.) and trypanosoma brucei rhodesiense (t.b.r.) were hydrolyzed and the liberated fatty acids were methylated before analysis by gas-liquid chromatography on capillary columns. the sums of the percentages for fatty acids from the different series were compared and the following relationships for the different trypanosomes obtained: --saturated fatty acids t.b.b. greater than t.b.g. greater than t.b.r. ... | 1988 | 3197256 |
| [trial of pentamidine in the treatment of trypanosomiasis of sheep inoculated with trypanosoma brucei brucei]. | an experimental study was carried out using 5 trypanosoma brucei brucei subcutaneously infected sheep. pentamidine treatment appeared in the csf. two animals were injected daily for 10 days and they died with drug intoxication. two animals received drug every 3 days for 15 days: one of them died, the other was cured after 3 weeks of set-back. this preliminary study should be completed by experimentation made over a more important period of time. | 1988 | 3197257 |
| [antiparasitic activity of cis-pt (ii) pentamidine in experimental trypanosomiasis of sheep caused by trypanosoma brucei brucei]. | the failure of trypanocidal therapeutics have made it a duty to use other classes of molecules which show a comparable trypanocidal efficacy with well-known medicines. in this study, the authors have evaluated the trypanocidal activity of a cis-platinum (ii) salt, dna-intercalating medicine used in antineoplastic therapeutics, associated with pentamidine: cis-pt (ii) pentamidine. after primary screenings on a murine model of t. brucei brucei, cis-pt (ii) pentamidine was evaluated on an experimen ... | 1988 | 3197258 |
| assessing hepatic dysfunction in rabbits experimentally infected with trypanosoma brucei. | | 1988 | 3201024 |
| spread of trypanosoma brucei to the nervous system: early attack on circumventricular organs and sensory ganglia. | the distribution of trypanosoma brucei brucei in the nervous system of experimentally infected sprague-dawley rats and balb/c and deer mice was examined with immunohistochemical techniques. the trypanosomes showed an early invasion in areas lacking a so-called blood-brain or blood-nerve barrier, i.e., in sensory ganglia and circumventricular organs including the area postrema, pineal gland, and median eminence. this distribution of trypanosomes may relate to the origin of cardinal symptoms of th ... | 1988 | 3216412 |
| polycistronic transcripts in trypanosomes and their accumulation during heat shock: evidence for a precursor role in mrna synthesis. | maturation of mrna precursors in trypanosomes involves an apparent trans splicing event in which a 39-nucleotide miniexon sequence, common to all trypanosome mrnas, is joined to the 5' end of a protein-coding exon. we demonstrate that the processing machinery responsible for the maturation of tubulin mrna precursors in trypanosoma brucei can be disrupted by heat shock. this results in an accumulation of polycistronic rna species and a decrease in the abundance of branched splicing intermediates. ... | 1988 | 3221866 |
| trypanocidal activity of a new series of arsenical compounds the spiroarsorans. | the trypanocidal activity of a new class of arsenical compounds, the spiroarsorans, was investigated against trypanosoma brucei brucei. the most active compound was found to be effective at a dose of 30 mg.kg-1 and had low toxicity. | 1988 | 3224710 |
| boundaries of telomere conversion in trypanosoma brucei. | active genes for variant-specific surface glycoproteins (vsgs) reside in telomeric expression sites and may be replaced by other vsg genes via telomere conversions. the availability of a complete map of expression site 221 in variant 221a made it possible to determine the boundaries of such conversions and the sequences that are involved. we have analysed five trypanosome populations that arose from variant 221a through replacement of the 221 gene by another vsg gene. in each of these relapsed p ... | 1988 | 3224817 |
| molecular heterogeneity of the isolated surface glycoprotein from variant antat 1.1 of trypanosoma brucei brucei. | variant surface glycoprotein (vsg) of trypanosoma brucei brucei antat 1.1 was released by means of the procedure described by baltz et al. ([1976], ann. immunol. [inst. pasteur] 127c, 761-774). the concanavalin-a chromatography yielded 3 vsg fractions according to the addition, in the elution buffer, of alpha-methyl-d-mannopyranoside, beta-mercaptoethanol, and sodium dodecyl sulfate. these vsg fractions showed heterogeneous behaviour on reverse-phase high performance liquid chromatography. the 3 ... | 1988 | 3228620 |
| suramin and metronidazole in the treatment of trypanosoma brucei rhodesiense. | | 1988 | 3232180 |
| the timing and frequency of hybrid formation in african trypanosomes during cyclical transmission. | the frequency of hybrid formation between two trypanosoma brucei clones during cyclical transmission through glossina morsitans centralis was analyzed. in two independent experiments, teneral g. m. centralis were infected with an equal mixture of two t. brucei clones showing different homozygous isoenzyme patterns for isocitrate dehydrogenase (icd; e.c.1.1.1.42) and alkaline phosphatase (ap; e.c. 3.1.3.1). trypanosomes were cyclically transmitted to mice from 23 infective flies and the subsequen ... | 1988 | 3237678 |
| trypanosoma brucei brucei: the catabolism of glycolytic intermediates by digitonin-permeabilized bloodstream trypomastigotes and some aspects of regulation of anaerobic glycolysis. | 1. the production of pyruvate, glycerol and glycerol-3-phosphate by intact and digitonin-permeabilized trypanosoma brucei brucei has been studied with glucose or the glycolytic intermediates as substrates. 2. under aerobic conditions hexosephosphates gave maximal glycolysis in the presence of 40-60 micrograms digitonin/10(8) trypanosomes while the triosephosphates gave it at 20-30 micrograms digitonin/10(8) trypanosomes. 3. in the presence of salicylhydroxamic acid, and the glycolytic intermedia ... | 1988 | 3248672 |
| the isolation of human serum-resistant trypanosoma (trypanozoon) species from zebra and impala in luangwa valley, zambia. | | 1988 | 3252589 |
| drug resistance in recent isolates of trypanosoma brucei and trypanosoma congolense. | | 1988 | 3253857 |
| the response of the nigerian indigenous chicken (gallus domesticus) to trypanosomes. | | 1988 | 3253858 |
| the role of polyamines in the growth and transformation of the african trypanosome. | | 1988 | 3255243 |
| nomenclature of trypanosoma evansi. | | 1988 | 3256130 |
| the acquisition of human serum resistance during cyclical passage of a trypanosoma brucei brucei clone through tsetse maintained on human serum: a retraction. | | 1988 | 3257003 |
| immune complex formation in the kidney: recent observations in experimental trypanosomiasis. | | 1988 | 3263090 |
| evidence for gene conversion between the phosphoglycerate kinase genes of trypanosoma brucei. | trypanosoma brucei contains a tandem array of three genes for phosphoglycerate kinase (pgkase), genes a, b and c, each coding for a different protein. we have compared allelic variants of this gene array and find evidence for gene conversion between the three genes. near the 3' end, the different alleles and gene b contain a variable sequence that is similar to the corresponding sequence in either gene a or gene c. this sequence is flanked by glycine triplets that are conserved in all pgkases fr ... | 1988 | 3267227 |
| structural and functional roles of glycosyl-phosphatidylinositol in membranes. | glycosylated forms of phosphatidylinositol, which have only recently been described in eukaryotic organisms, are now known to play important roles in biological membrane function. these molecules can serve as the sole means by which particular cell-surface proteins are anchored to the membrane. lipids with similar structures may also be involved in signal transduction mechanisms for the hormone insulin. the utilization of this novel class of lipid molecules for these two distinct functions sugge ... | 1988 | 3276003 |
| biogenesis of glycosomes of trypanosoma brucei: an in vitro model of 3-phosphoglycerate kinase import. | glycosomes are intracellular, membrane-bound microbody organelles of trypanosomes and leishmania. nine glycolytic enzymes are the major protein components of the glycosomes of trypanosoma brucei long-slender bloodstream forms. glycosomal proteins are believed to be synthesized in the cytoplasm and inserted across the glycosomal membrane posttranslationally. we have developed an in vitro protein import assay for the study of glycosomal biogenesis in t. brucei. all nine glycosomal glycolytic enzym ... | 1988 | 3282231 |
| origins and organization of genetic diversity in natural populations of trypanosoma brucei. | experimental work has established that a sexual process can occur in african trypanosomes (jenni, marti, schweizer, betschart, le page, wells, tait, paindavoine, pays & steinert, 1986; paindavoine, zampetti-bosseler, pays, schweizer, guyaux, jenni & steinert, 1986; tait, personal communication). however, the role of the process in natural populations of trypanosomes is poorly understood. this paper considers what information can be gained from analyses of isoenzyme polymorphism. a cladistic appr ... | 1988 | 3287284 |
| effects of t-butyl-4-hydroxyanisole and other phenolic antioxidants on tumoral cells and trypanosoma parasites. | the antioxidant food additives 2(3)-tert-butyl-4-hydroxyanisole (bha), 2,6-di(tert-butyl)-p-cresol (bht) and the methyl and propyl esters of gallic acid inhibited trypanosoma cruzi culture growth and oxygen consumption. the i50 values for growth and oxygen uptake with bha were 0.284 and 0.400 and for bht 0.083 and 0.235 mm, respectively. moreover, bha inhibited the respiration of several tumor cells, as well as of the procyclic and bloodstream trypomastigote forms of t. brucei brucei, with i50 i ... | 1988 | 3292295 |
| effect of 3-aminobenzamide on the frequency of antigen switching in trypanosoma brucei in vitro. | | 1987 | 3297066 |
| a new method for fixation and preservation of trypanosomal antigens for use in the indirect immunofluorescence antibody test for diagnosis of bovine trypanosomiasis. | a new method for fixation of trypanosomes for use in the indirect immunofluorescent antibody test (ifat) is described. the method involves fixation of live trypanosomes, in suspension, using a mixture of 80% cold acetone and 0.25% formalin in saline. the fixed trypanosomes were stored in suspension at -60 degrees c, 4 degrees c or at room temperature for at least one year without loss of antigenicity. using trypanosomes prepared this way as antigens in ifat, species-specific antibodies were dete ... | 1987 | 3299658 |
| similarity in variable antigen type composition of trypanosoma brucei rhodesiense populations in different sites within the mouse host. | trypanosoma brucei rhodesiense subpopulations in different sites within the body of infected mice were isolated and enumerated on day 6 of cyclically transmitted infections. most trypanosomes were in the blood vasculature and spleen but approximately 6% occurred in lymph nodes and about 9% were extravascular. most of the extravascular trypanosomes were in the peritoneal and pleural cavities; significant numbers also occurred in the brain and kidneys. six major variable antigen types (vats) were ... | 1986 | 3299895 |
| antigenic variation in african trypanosomes. | | 1987 | 3304830 |
| monoclonal antibodies that distinguish trypanosoma congolense, t. vivax and t. brucei. | monoclonal antibodies (moabs) were derived against in-vitro-propagated procyclic forms of trypanosoma congolense, t. vivax, t. brucei brucei and t.b. rhodesiense in order to identify antigens for use in immunodiagnosis of african trypanosomiasis. the antibodies have been tested against procyclic and bloodstream form trypanosomes of 13 t. congolense, six t. vivax six t.b. brucei, four t.b. rhodesiense, five t.b. gambiense and three t. simiae isolates from different geographical areas by indirect ... | 1987 | 3306569 |
| the biochemistry of african trypanosomes and its significance for chemotherapy. | | 1987 | 3309362 |
| kinetic properties of triose-phosphate isomerase from trypanosoma brucei brucei. a comparison with the rabbit muscle and yeast enzymes. | the kinetic properties of trypanosoma brucei brucei triose-phosphate isomerase are compared with those of the commercially available rabbit muscle and yeast enzymes and with published data on the chicken muscle enzyme. with glyceraldehyde 3-phosphate as substrate km = 0.25 +/- 0.05 mm and kcat = 3.7 x 10(5) min-1. with dihydroxyacetone phosphate as substrate km = 1.2 +/- 0.1 mm and kcat = 6.5 x 10(4) min-1. the ph dependence of km and vmax at 0.1 m ionic strength is in agreement with the results ... | 1987 | 3311744 |
| lysosomal and non-lysosomal peptidyl hydrolases of the bloodstream forms of trypanosoma brucei brucei. | african trypanosomes have thiol-dependent proteolytic activity that resembles some of the cathepsin-like activity found in mammalian lysosomes [lonsdale-eccles, j. d. & mpimbaza, g. w. n. (1986) eur. j. biochem. 155, 469-473]. here we show that this activity is found in lysosome-like organelles which we have isolated (density = 1.082 g/cm3 in percoll) from bloodstream forms of trypanosoma brucei brucei. they are approximately 250 nm in diameter, are bounded by a single limiting membrane, and con ... | 1987 | 3319612 |
| import of fructose bisphosphate aldolase into the glycosomes of trypanosoma brucei. | the glycolytic enzymes of trypanosomatids are compartmentalized within peroxisome-like microbodies called glycosomes. fructose bisphosphate aldolase is synthesized on free polysomes and imported into glycosomes within 5 min. peptide mapping reveals no primary structural differences between the in vivo-synthesized protein and that made in vitro from a synthetic template. however, native aldolase from glycosomes is partially protease resistant, whereas the in vitro translation product is not. puls ... | 1987 | 3320052 |
| peptidase in the plasma of mice infected with trypanosoma brucei brucei. | the plasma of mice infected with pleomorphic trypanosoma brucei brucei contains a peptidase which has the same electrophoretic mobility on starch gels as a parasite peptidase. an enzyme with this electrophoretic mobility was not detected in the plasma of uninfected mice. the molecular weight of this enzyme in either parasite lysate or plasma from infected mice was approximately 40,000 da when assayed on a size exclusion column using high-performance liquid chromatography. the enzyme can cleave t ... | 1987 | 3320889 |
| modulation of lymphokine production during experimental trypanosoma brucei infection in inbred mouse strains. | | 1987 | 3322213 |
| purification of african trypanosomes can cause biochemical changes in the parasites. | bloodstream forms of african trypanosomes are routinely purified from blood components by a combination of centrifugation and chromatography on deae cellulose at ph 8.0. here we report that the nonphysiological conditions used for deae chromatography of the parasites result in changes in the atp levels of the trypanosomes and an enhanced release from the parasites of proteins such as variable surface glycoprotein, peptidase, and phospholipase. some of these changes can be reduced by the addition ... | 1987 | 3323477 |
| expression of the alpha and beta tubulin genes of the african trypanosome in escherichia coli. | the african trypanosome, trypanosoma brucei, contains multiple genes for both alpha- and beta-tubulins, which code for similar if not identical proteins. studies of the structure and function of trypanosome microtubules have been limited due to the difficulties in obtaining sufficient amounts of purified tubulin. to produce large amounts of purified tubulin for studies of structure and function and to begin developing a system for producing systematic alterations of tubulin structure we have clo ... | 1987 | 3327752 |
| comparison between bloodstream and procyclic form trypanosomes for serological diagnosis of african human trypanosomiasis. | trypanosoma brucei brucei mitat 1.2 bloodstream and corresponding procyclic forms, as well as procyclics of t. b. gambiense and t. b. rhodesiense, were fixed, in suspension, using a mixture of 80% acetone and 0.25% (v/v) formalin in saline and used as antigens for diagnosis of african human trypanosomiasis by the indirect immunofluorescent antibody test. t. b. brucei bloodstream forms detected 41/42 and 37/41 parasitologically diagnosed cases of t. b. rhodesiense and t. b. gambiense trypanosomia ... | 1987 | 3328347 |
| topogenesis of glycolytic enzymes in trypanosoma brucei. | the protozoan haemoflagellate trypanosoma brucei, differs from other eukaryotic cells in that it contains nine enzymes involved in glucose and glycerol metabolism which are associated with microbody-like organelles called glycosomes. the information available to date indicates that glycosomal enzymes are synthesized as polypeptides of mature size. for three of them, glyceraldehyde-phosphate dehydrogenase, aldolase and glycerol-3-phosphate dehydrogenase, it has been shown that they are made on fr ... | 1987 | 3332763 |
| a flagellar pocket membrane fraction from trypanosoma brucei rhodesiense: immunogold localization and nonvariant immunoprotection. | in contrast to the abundance of detailed information on variant-specific surface coat antigens of african trypanosomes, data on possible common or nonvariant antigens within these protozoa are surprisingly limited. in this study, the cellular localization and protective potential of a previously characterized flagellar pocket membrane (fpm) fraction were determined. immunogold staining of live trypanosome suspensions at 0 to 4 degrees c by using anti-fpm hyperimmune serum raised in rabbits as th ... | 1988 | 3335412 |
| genetics of resistance to the african trypanosomes. vii. trypanosome virulence is not linked to variable surface glycoprotein expression. | the question of linkage of virulence traits to variable surface glycoprotein (vsg) expression in african trypanosomiasis was addressed. previously we demonstrated that daughter cells arising in mice infected with a genetically homogeneous trypanosome population of trypanosoma brucei rhodesiense were more virulent than the infecting population (j. a. inverso and j. m. mansfield, j. immunol. 130:412, 1983). these virulent trypanosomes expressed differences in surface phenotype compared with the in ... | 1988 | 3335780 |
| the cap of both miniexon-derived rna and mrna of trypanosomes is 7-methylguanosine. | most, if not all, trypanosome mrnas have the same 35-base sequence at their 5' terminus which is derived from a short rna (medrna) probably by the process of trans-splicing. it is of interest, evolutionarily and mechanistically, to determine the chemical structure of the 5' terminus of the precursor (medrna) and product (mrna). we demonstrate here that the cap structure of both is most probably 7-methylguanosine in a 5',5' triphosphate linkage, consistent with a precursor/product relationship. | 1988 | 3336365 |
| identification of an acid-lipase in human serum which is capable of solubilizing glycophosphatidylinositol-anchored proteins. | a lipase has been identified in human serum which can convert the membrane form of the variant surface glycoprotein of trypanosoma brucei to a water soluble form. the conversion can be monitored by loss of [3h] myristic acid incorporated into the diacylglycerol of the glycophosphatidylinositol membrane anchor of the protein, but does not lead to the exposure of the antigenic determinant in the polar head group of the glycolipid. the serum lipase is a glycoprotein, and is optimally active at ph 5 ... | 1988 | 3337726 |
| trypanosoma brucei: susceptibility to hydrogen peroxide and related products of activated macrophages. | the susceptibility of procyclic, trypsinized, or bloodstream forms of trypanosoma brucei to lysis by hydrogen peroxide and by activated mouse macrophages was investigated in vitro using the release of biosynthetically labeled proteins as an assay. uncoated parasites were more resistant than coated bloodstream forms in both cases. macrophage trypanolysis upon triggering with phorbol myristate acetate occurred extracellularly and seemed to depend on the release of hydrogen peroxide, as it was prev ... | 1988 | 3338544 |
| variable rna polymerase populations in the life cycle of trypanosoma brucei. | dna-dependent rna polymerase from blood forms and culture forms of the parasitic protozoan trypanosoma brucei was resolved into multiple peaks of activity by deae-sephadex chromatography. the enzyme from the two forms was found to be different by several criteria, suggesting that it is subject to developmental control. | 1988 | 3338570 |
| candidate glycophospholipid precursor for the glycosylphosphatidylinositol membrane anchor of trypanosoma brucei variant surface glycoproteins. | trypanosoma brucei variant surface glycoproteins are apparently synthesized with a hydrophobic carboxyl-terminal peptide that is cleaved and replaced by a complex glycosylphosphatidylinositol membrane anchor within 1 min of the completion of polypeptide synthesis. the rapidity of this carboxyl-terminal modification suggests the existence of a prefabricated core glycolipid that would be transferred en bloc to the variant surface glycoprotein polypeptide. we report the purification and chemical ch ... | 1988 | 3339000 |
| intracellular transport of a variant surface glycoprotein in trypanosoma brucei. | trypanosome variant surface glycoproteins (vsgs) have a novel glycan-phosphatidylinositol membrane anchor, which is cleavable by a phosphatidylinositol-specific phospholipase c. a similar structure serves to anchor some membrane proteins in mammalian cells. using kinetic and ultrastructural approaches, we have addressed the question of whether this structure directs the protein to the cell surface by a different pathway from the classical one described in other cell types for plasma membrane and ... | 1988 | 3339091 |
| glycosyl-phosphatidylinositol moiety that anchors trypanosoma brucei variant surface glycoprotein to the membrane. | two forms of protein-membrane anchor have been described for the externally disposed glycoproteins of eukaryotic plasma membranes; namely, the hydrophobic transmembrane polypeptide and the complex glycosylphosphatidylinositol (g-pi) moiety. the chemical structures of the major species of g-pi anchors found on a single variant surface glycoprotein (vsg) of the parasitic protozoan trypanosoma brucei were determined by a combination of nuclear magnetic resonance spectroscopy, mass spectrometry, che ... | 1988 | 3340856 |
| two distinct succinate thiokinases in both bloodstream and procyclic forms of trypanosoma brucei. | two succinate thiokinase activities specific for either adenine or guanine nucleotides have been found in trypanosoma brucei. key glycolytic and citric acid cycle enzymes were measured to show repression of glycolysis and derepression of the citric acid cycle in the procyclic form, relative to the bloodstream form. a marked rise in adenine-linked succinate thiokinase activity accompanied a rise in activity of citric acid cycle enzymes. however, guanine-linked succinate thiokinase was found to in ... | 1988 | 3348777 |
| stable variant-specific transcripts of the variant cell surface glycoprotein gene 1.8 expression site in trypanosoma brucei. | the structure and transcriptional regulation of the 1.8 variant cell surface glycoprotein (vsg) gene expression site located on a 430-kilobase (kb) chromosome was examined in a 430-kb-chromosome-specific library. using 32p-labeled nascent transcripts generated by nuclear run-on, we selected recombinant clones derived from the 430-kb chromosome which were coordinately activated with the 1.8 vsg gene. the results show that a repetitive region with a minimum size of 27 kb is coordinately activated ... | 1988 | 3352606 |
| the in vitro and in vivo effects of metronidazole and chloroquine on trypanosoma brucei brucei. | bloodstream forms of trypanosoma brucei brucei were grown over baby hamster kidney cells in minimum essential medium with various concentrations of metronidazole (flagyl) and chloroquine. both drugs inhibited the multiplication of the parasite in vitro. the least effective concentrations for metronidazole and chloroquine were 0.003 mg/ml and 0.0024 mg/ml, respectively. groups of 12-day-old female cdi mice were treated with 1 of the 2 drugs at 24, 48, and 72 hr after t. brucei infection. the drug ... | 1988 | 3357110 |
| a microtubule-binding protein of trypanosoma brucei which contains covalently bound fatty acid. | covalently linked fatty acids are increasingly recognized as an important type of post-translational protein modification. many of such acylated proteins are found associated with cellular membranes. the membrane skeleton of the parasitic hemoflagellate trypanosoma brucei consists of a regular array of microtubules which are tightly bound to the overlying cell membrane. a microtubule-binding protein (p41) has been identified within this structure which carries covalently bound fatty acid. the fa ... | 1988 | 3360790 |
| a model of tsetse-transmitted animal trypanosomiasis. | the data needed to develop analytical models of trypanosomiasis transmission have become available only recently. by making some simplifying assumptions, models of the dynamics of the disease in vector, cattle and wild mammal populations can be constructed in order to determine criteria for successful disease control by mass and targetted chemotherapy, and by vector control. the heterogeneity in transmission due to tsetse fly feeding preferences and the variability of immunological characteristi ... | 1988 | 3362578 |
| polygene transcripts are precursors to calmodulin mrnas in trypanosomes. | in african trypanosomes, calmodulin is encoded by a small family of tandemly repeated genes consisting of three to four units. we show that all the members of the calmodulin cluster of trypanosoma brucei gambiense are expressed. in addition to mature mrnas, steady-state rna contains a small percentage of polygene transcripts which comprise at least two and probably all calmodulin genes. the 5' ends of a portion of these molecules appear to be indistinguishable from those of mature calmodulin mrn ... | 1988 | 3366120 |
| gossypol-induced death of african trypanosomes. | | 1988 | 3366212 |
| relapses in dogs experimentally infected with trypanosoma brucei and treated with diminazene aceturate or isometamidium chloride. | twenty dogs of mixed local east african breeds were used. five of the dogs were uninfected controls and 15 were infected with t. brucei (ilrad 273). five of the infected dogs were untreated controls, five were treated with a high curative dose of diminazene aceturate, (7 mg kg-1 body weight (wt.), and five were given a subcurative dose of isometamidium chloride (1 mg kg-1 body wt.). the drugs, given at 8 days post infection (d.p.i..), led to apparent recovery. the antibody titres, however, remai ... | 1988 | 3369073 |
| most proteins, including fructose bisphosphate aldolase, are stable in the procyclic trypomastigote form of trypanosoma brucei. | procyclic trypanosoma brucei were labelled with [35s]methionine, then incubated for up to 2 days in medium containing excess unlabelled methionine under conditions suitable for exponential growth. neither fructose bisphosphate aldolase, a glycosomal enzyme, nor any of the major labelled proteins showed any detectable degradation. | 1988 | 3374524 |
| 13c-nmr analysis of alanine metabolism by isolated perfused livers from c3heb/fej mice infected with african trypanosomes. | 1. isolated perfused livers from mice infected with trypanosoma brucei rhodesiense formed substantially more [3-13c]-lactate from [3-13c]-alanine than livers from uninfected mice. quantities formed by infected livers increased as infection progressed. 2. infected livers produced more 13c-labeled glutamate and glutamine, with label scrambled between c-2 and c-3. scrambling also produced [2,3-13c]-aspartate, [2-13c]-alanine and [2-13c]-lactate. delayed appearance of label in c-4 of glutamate/gluta ... | 1988 | 3378406 |
| rapid lateral diffusion of the variant surface glycoprotein in the coat of trypanosoma brucei. | the membrane form of the variant surface glycoprotein (mfvsg) is anchored in the plasma membrane of trypanosoma brucei by a dimyristoylphosphatidylinositol residue connected via a glycan to the cooh-terminal amino acid. the glycoprotein molecules are tightly packed, forming a coat that is impenetrable to lytic serum components. lateral diffusion of mfvsg was measured by the fluorescence recovery after photobleaching technique. mfvsg labeled on the cell surface with rhodamine-conjugated anti-vsg ... | 1988 | 3382629 |
| the humoral defense system in tsetse: differences in response due to age, sex and antigen types. | inoculation of live escherichia coli into tsetse flies, glossina morsitans morsitans, stimulated a higher antibacterial immune response in females than in males. it increased with age in females from emergence to approximately 2 weeks and thereafter declined. in males, there was also a significant decrease in immune response with aging. inoculation of killed bacteria failed to stimulate antibacterial activity but stimulated a lysozyme response which was weaker than that stimulated by live bacter ... | 1988 | 3384155 |
| structure and transcription of the actin gene of trypanosoma brucei. | in trypanosoma brucei, the actin gene is present in a cluster of two, three, or four tandemly linked copies, depending on the strain. each cluster seems to exist in two allelic versions, as suggested by the polymorphism of both gene number and restriction fragment length in the dna from cloned trypanosomes. the amplification of the gene copy number probably occurs through unequal sister chromatid exchange. the chromosomes harboring the actin genes belong to the large size class. the coding seque ... | 1988 | 3386635 |
| characterization of the genes for fructose-bisphosphate aldolase in trypanosoma brucei. | in trypanosoma brucei stock 427 the glycolytic enzyme fructose-bisphosphate aldolase is encoded by two tandemly linked genes of identical sequence. such a tandem arrangement of aldolase genes is also present in other t. brucei stocks of unrelated origin. in stock 427 one of the allelic genes is a pseudogene, as a result of a one-nucleotide deletion. the genes code for a polypeptide of 371 amino acids, with a calculated molecular weight of 40,940. the protein that is predicted from the gene seque ... | 1988 | 3386689 |
| development of trypanosoma congolense, t vivax and t brucei in the skin reaction induced in goats by infected glossina morsitans centralis: a light and electron microscopical study. | the development and distribution of trypanosoma congolense, t vivax and t brucei in the skin of goats was examined after the animals were bitten by infected glossina morsitans centralis. following the tsetse bite, the trypanosomes in the skin multiplied, reaching maximum numbers when the skin reaction (chancre) of the host attained its maximum size. in goats infected with t vivax and t brucei, trypanosomes were observed circulating in the blood before the peak of the chancre, while in t congolen ... | 1988 | 3387665 |
| the role of lectins and trypanosome genotype in the maturation of midgut infections in glossina morsitans. | feeding d + glucosamine to glossina morsitans throughout their life significantly reduced the proportions of midgut infections which developed into mature infections with three different stocks of trypanosoma congolense. in one stock of t. congolense, maturation was completely blocked by this carbohydrate, which is known to specifically inhibit tsetse midgut lectin activity. similar experiments with t. brucei showed that d + glucosamine also inhibited maturation and, when combined with results f ... | 1988 | 3387828 |
| presence of a lipophosphoglycan in two variants of trypanosoma brucei brucei. | for the family of trypanosomatidae (trypanosoma and leishmania) the organization of the glycoproteins on the cell surface is a well documented structural feature, because their plasma membranes are potential target for chemotherapy. by using metabolic labeling ( [32p] phosphate, [3h]-myristic acid, [3h]-galactose) and by appropriate fractionated extraction, we have found a trypanosomal molecule which has electrophoretic and chromatographic properties consistent with the lipophosphoglycan of leis ... | 1988 | 3390183 |
| large microtubule-associated protein of t. brucei has tandemly repeated, near-identical sequences. | the parasitic protozoon trypanosoma brucei contains a highly organized membrane skeleton, consisting of a dense array of parallel, singlet microtubules that are laterally interconnected and that are also in tight contact with the overlying cell membrane. a high molecular weight, heat-stable protein from this membrane skeleton was isolated that is localized along the microtubules. protease digestion experiments and sequencing of a cloned gene segment showed that most of the protein is built up by ... | 1988 | 3393912 |
| trypanocidal activity of free and carrier bound daunorubicin. | activities of a range of macromolecular conjugates of daunorubicin against trypanosoma brucei rhodesiense in vitro and in vivo are described and compared to those of free daunorubicin. conjugates tested were daunorubicin attached to bovine serum albumin by (i) a labile 'glutaraldehyde' linkage (d-bsag), and (ii) a stable succinyl linkage (d-bsas), daunorubicin covalently linked to agarose beads (d-ag), and daunorubicin adsorbed onto polyisobutylcyanoacrylate nanoparticles (d-pica). trypanocidal ... | 1988 | 3396080 |
| trypanosoma brucei gambiense and t. b. rhodesiense: concanavalin a binding to the membrane and flagellar pocket of bloodstream and procyclic forms. | we have measured binding of fluorescein-conjugated succinyl-concanavalin a (fl-s-con a) to bloodstream and procyclic forms of trypanosoma brucei gambiense and to bloodstream forms of t. b. rhodesiense by flow cytofluorimetry. bloodstream forms bound an order of magnitude less lectin than procyclic forms. trypsin-treating cells enhanced binding of fl-s-con a to bloodstream forms 3-16-fold depending on the strain and the length of trypsinization but had little effect on fl-s-con a binding by procy ... | 1988 | 3397913 |
| nuclear factors binding to the mini-exon repeat of trypanosoma brucei. | in trypanosomes and related kinetoplastida a common short 5' leader sequence is encoded by the highly repetitive mini-exon gene and added to all protein coding mrnas by trans-splicing. to initiate a search for transcription factors associated with transcription of the mini-exon we have used an electrophoretic mobility shift assay to detect trypanosome nuclear factors which interact specifically with mini-exon dna. a factor present in the nuclei of both infectious bloodstream forms and non-infect ... | 1988 | 3398890 |
| prevalence of trypanosomiasis in cattle in south-west zambia. | a trypanosomiasis survey was conducted in south-west zambia. from a total of 3,346 cattle sampled 342 cattle showed a positive trypanosomiasis parasitaemia. during the survey trypanosome species and pcv values were also recorded. with simple statistical analysis populations with higher and lower prevalence rates were differentiated. the results indicated that the kwando river basin tsetse fly belt and the kafue river basin tsetse fly belt infested a larger area than originally assumed and that a ... | 1988 | 3400114 |
| ro 15-0216: a nitroimidazole compound active in vitro against human and animal pathogenic african trypanosomes. | in vitro systems for the continuous cultivation of trypanosoma brucei brucei, t. b. gambiense, t. b. rhodesiense, t. congolense and t. vivax were used to determine the antitrypanosomal activity of the 2-substituted nitroimidazole ro 15-0216. for all trypanosome species, the concentration which inhibited parasite growth by 50% (ic50 value) was established: 0.0957 microgram ml-1 (t. b. brucei tc221), 0.1327 microgram ml-1 (t. b. gambiense stib 754-a), 0.0450 microgram ml-1 (t. b. rhodesiense stib ... | 1988 | 3401068 |