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evaluation of antigen-coating procedures of enzyme-linked immunosorbent assay method for detection of trypanosomal antibodies.research was undertaken to improve the antigen-coating step of indirect enzyme-linked immunosorbent assay (elisa) method through the use of polystyrene 96-well plates precoated with antigenically stabile crude trypanosomal antigens. the plates were precoated with antigens, air dried and sealed before being packed in plastic bags with silica gel desiccant packets. such plates stored at +4 and +37 degrees c provided an assay performance, which was superior to that of plates freshly coated with ant ...200010828507
pathways of glucose catabolism in procyclic trypanosoma congolense.studies of respiration on glucose in procyclic trypanosoma congolense in the presence of rotenone, antimycin, cyanide, salicylhydroxamic acid and malonate have indicated the presence of nadh dehydrogenase, cytochrome b-c1, cytochrome aa3, trypanosome alternate oxidase and nadh fumarate reductase/succinate dehydrogenase pathway that contributes electrons to coenzyme q of the respiratory chain. the rotenone sensitive nadh dehydrogenase, the trypanosome alternate oxidase, and cytochrome aa3 account ...199910844979
[vectorial competence of non-teneral glossina morsitans morsitans (mall strain) flies infected by trypanosoma (nannomonas) congolense il 1180].non-teneral tsetse flies of glossina morsitans morsitans (strain mall) about 16 days old were fed, once, on a rat infected by trypanosoma congolense il 1180. the global vectorial competence (vc) of these flies was appraised at 0.1035. vc in males was more important than for females. infection by mesoprocyclic index was greater in female flies than in male ones, whereas for metacyclic index the reverse was true. this work shows that the age limits, but does not impede metacyclogenesis of non-tene ...200010863619
grouping of trypanosome species in mixed infections in glossina pallidipes.trypanosomes in the dissection-positive proboscis of glossina pallidipes were identified by pcr using species-specific primers. of the 3741 flies dissected 643 were proboscis positive. pcr was performed on 406 dissection-positive probosces giving positive identifications in 352 (86.7%) and infection rates of 14.8% for congolense-type infections, 2.8% for vivax-type infections and 1.4% for the unidentified group. of the 352 pcr identified infections 225 were single, 111 were double, 13 were tripl ...200010874721
innate resistance to experimental african trypanosomiasis: differences in cytokine (tnf-alpha, il-6, il-10 and il-12) production by bone marrow-derived macrophages from resistant and susceptible mice.resistance to african trypanosomiasis is under multigenic control. balb/c mice are highly susceptible while c57bl/6 mice are relatively resistant. macrophages eliminate opsonized trypanosomes from the bloodstream and are involved in immunosuppression. we therefore investigated the production of a number of cytokines (il-10, il-6, tnf-alpha and il-12) by bone marrow-derived macrophages (bmdm) from c57bl/6 and balb/c mice following challenge with either trypanosoma congolense or trypanosoma brucei ...200010880248
the structure-function relationship of functionally distinct but structurally similar hexose transporters from trypanosoma congolense.we have previously characterized, in trypanosoma brucei, a multigene family encoding two developmentally regulated glucose transporters that are 80% identical at the amino-acid level. we report here the characterization of the homologous glucose transporters (tcoht1 and tcoht2) in trypanosoma congolense, an african trypanosome responsible for disease in domestic animals. both tcoht isoforms, which are 92.4% identical, are encoded by a single cluster of genes containing two copies of tcoht1 and t ...200010903520
fine mapping of trypanosomiasis resistance loci in murine advanced intercross lines.we have previously reported the results of genome-wide searches in two murine f(2) populations for qtls that influence survival following trypanosoma congolense infection. three loci, tir1, tir2, and tir3, were identified and mapped to mouse chromosomes (chrs) 17, 5, and 1 respectively, with confidence intervals (cis) in the range 10-40 cm. the size of these cis is to a large degree the consequence of limited numbers of recombination events in small chromosomal regions in f(2) populations. a num ...200010920233
multiple-drug resistant trypanosoma congolense populations in village cattle of metekel district, north-west ethiopia.investigations were carried out to determine the prophylactic activity of isometamidium chloride in village populations of cattle naturally infected with trypanosomes in metekel district, northwest ethiopia. in a cross-sectional study in march 1997, 484 randomly selected cattle from four villages were examined for trypanosome infections by the dark ground/phase contrast buffy coat technique (bct). the trypanosome prevalence was 17.2%. trypanosoma congolense was the dominant species accounting fo ...200010974163
feeding behaviour of glossina pallidipes and g. morsitans centralis on boran cattle infected with trypanosoma congolense or t. vivax under laboratory conditions.in field studies, tsetse flies (diptera: glossinidae) feed more successfully on cattle infected with trypanosoma congolense broden (kinetoplastida: trypanosomatidae) than on cattle infected with t. vivax ziemann or uninfected cattle. here we describe the first laboratory investigation of this phenomenon. in the first experiment, caged glossina pallidipes austen were fed for 1 and 5 min on a boran steer infected with t. congolense clone il 1180 and on an uninfected steer. feeding success was reco ...200011016437
novel species specific antigens of trypanosoma congolense and their different localization among life-cycle stages.seven monoclonal antibodies (mabs) were raised against trypanosoma congolense procyclic form (pcf). localization of the antigens recognized by the mabs was determined in bloodstream form (bsf), pcf, epimastigote form (emf) and metacyclic form (mcf) by confocal laser scanning microscopy (clsm). two mabs (10f9 and 20h12) showed different fluorescent patterns among different life-cycle stages of the parasite. the 10f9 recognized a 76 kda antigen of all life-cycle stages of the parasite and the anti ...200011073073
comparison of the isometamidium-based trypanocidal drugs samorin and veridium in cattle under field conditions at nguruman, kenya.the trypanocidal activity of two commercially available isometamidium-based products, samorin (merial, usa) and veridium (sanofi santé nutrition animale, france), used at a dose rate of 0.5 mg kg(-1) bodyweight, was compared in a field trial involving groups of approximately 30 zebu cattle in a trypanosomosis endemic part of south-western kenya. the trial took place between april 1997 and march 1998 during a time of higher than normal rainfall that resulted in periods of high trypanosome challen ...200011080510
control of glossina longipennis (diptera: glossinidae) by insecticide-treated targets at galana ranch, kenya, and confirmation of the role of g. longipennis as a vector of cattle trypanosomiasis.glossina longipennis corti was studied in galana ranch, kenya over a four year period, in two areas (tank e and lali) where the species was abundant and other species were absent or scarce. there was active transmission of trypanosomiasis to cattle in both areas, the parasite species being trypanosoma vivax ziemann and t. congolense broden. mean infection rates of the g. longipennis were 1.1% and 0. 55% for t. vivax and t. congolense respectively at tank e, and 0.88% and 0.15% at lali. experimen ...200011082557
susceptibility and resistance to trypanosoma congolense infections.we have put emphasis on recent findings in experimental trypanosoma congolense infections in highly susceptible balb/c and relatively resistant c57bl/6 mice. based on various analyses, it has been shown that a major difference in resistance to t. congolense infections is expressed early in infection at the macrophage level. a novel plastic-adherent thy1.2(+) suppressor lymphocyte, which in absolute synergy with a thy 1.2(-) cell exerts its suppression via interleukin-10 and interferon-gamma open ...200011113381
application of pcr and dna probes in the characterisation of trypanosomes in the blood of cattle in farms in morogoro, tanzania.polymerase chain reaction (pcr) and deoxyribonucleic acid (dna) probes were used to characterise trypanosomes from cattle in morogoro region of tanzania. blood samples collected from 390 beef and dairy cattle in selected farms in morogoro region were examined for presence of trypanosomes using the buffy coat technique (bct) and blood smears (bss). fifty-two animals were found infected: 40 with trypanosoma congolense, 10 with t. vivax and two with both t. congolense and t. vivax. dna extracted fr ...200111113548
the decline of anti-trypanosomal antibody levels in cattle after treatment with trypanocidal drugs and in the absence of tsetse challenge.the decline of anti-trypanosomal antibody levels in cattle after treatment with trypanocidal drugs was investigated using an anti-trypanosomal antibody-detection enzyme-linked immunosorbent assay (elisa). the decline of antibody levels differed between experimental animals but went through two phases. during the first 5 months after trypanocidal drug treatment, the decline is rapid with a monthly average decline of 10% of the average percentage positivity during the treatment. between months 6 a ...200011114388
the distribution of tsetse (diptera: glossinidae) and bovine trypanosomosis in the matutuine district, maputo province, mozambique.a tsetse and bovine trypanosomosis survey was conducted during 1998 and 1999 in the matutuine district of maputo province (mozambique). a total of 59 glossina brevipalpis and 17 glossina austeni were captured throughout the district. survey results suggest that glossina brevipalpis is mainly concentrated in dense vegetation along the maputo river and in the wetlands east of the river. g. austeni, on the other hand, was captured mainly in dense thickets in drier areas. both tsetse species are sus ...200011131117
gpi-anchored proteins: now you see 'em, now you don't.many cell surface proteins are attached to membranes via covalent glycosylphosphatidylinositol (gpi) anchors that are posttranslationally linked to the carboxy-terminus of the protein. removal of the gpi lipid moieties by enzymes such as gpi-specific phospholipases or by chemical treatments generates a soluble form of the protein that no longer associates with lipid bilayers. we have found that the removal of lipid moieties from the anchor can also have a second, unexpected effect on the antigen ...200111156970
the major cell surface glycoprotein procyclin is a receptor for induction of a novel form of cell death in african trypanosomes in vitro.bloodstream forms (bsf) and procyclic culture forms (pcf) of african trypanosomes were incubated with a variety of lectins in vitro. cessation of cell division and profound morphological changes were seen in procyclic forms but not in bsf after incubation with concanavalin a (con a), wheat germ agglutinin and ricinus communis agglutinin. these lectins caused the trypanosomes to cease division, become round and increase dramatically in size, the latter being partially attributable to the formatio ...200011163441
estimation of trypanosomal status by the buffy coat technique and an antibody elisa for assessment of the impact of trypanosomosis on health and productivity of n'dama cattle in the gambia.the buffy coat/dark ground phase contrast technique (bct) and an indirect antibody enzyme immunoassay (elisa) were employed to assess the trypanosomal status of 32 n'dama cattle, aged 19-28 months, exposed to natural challenge of glossina morsitans submorsitans and g. palpalis gambiensis. prior to the start of the investigation animals experienced 9-16 months of tsetse challenge in the study area. blood and corresponding serum samples were examined monthly for a period of 8 months for patent par ...200111163695
charting methods to monitor the operational performance of elisa method for the detection of antibodies against trypanosomes.four indirect enzyme-linked immunosorbent assays (elisas) for the detection of antibody against trypanosomes using antigen-precoated plates (trypanosoma congolense and t. vivax) were used in 15 veterinary diagnostic laboratories in africa and europe. the study provided data allowing an evaluation of charting methods with respect to the operational performance of each elisa. data from standardised internal quality control (iqc) samples were plotted on charts and used as the assay performance indi ...200111182234
pathobiochemical mechanisms involved in the control of the disease caused by trypanosoma congolense in african grey duiker (sylvicapra grimmia).the course of trypanosoma congolense infections in african grey duiker (sylvicapra grimmia) and sheep and goats were studied. several parameters suggested that the grey duiker was much more resistant to trypanosomosis than sheep and goats. they showed increases in weight during infection, had a much longer pre-patent period, and their peak parasitaemia levels were about 100-fold lower than those of sheep and goats. parasites were no longer detected in grey duiker blood 35 days after infection. a ...200111182235
in vitro erythrophagocytosis by cultured macrophages stimulated with extraneous substances and those isolated from the blood, spleen and bone marrow of boran and n'dama cattle infected with trypanosoma congolense and trypanosoma vivax.a standard radioactive chromium (51cr) release assay was used to assess the in vitro phagocytosis and lysis of bovine erythrocytes by cultured splenic, bone marrow and peripheral blood monocyte-derived (pbm) macrophages isolated from healthy and trypanosoma congolense and t. vivax-infected cattle of the boran and n'dama breeds. recombinant cytokines (rhutnf-alpha and rbolfn-gamma) and non-acid-dialysed peripheral blood mononuclear cell (pbmnc) culture supernatants stimulated these pbm for enhanc ...200011206395
differential expression of surface membrane antigens on bovine monocytes activated with recombinant cytokines and during trypanosoma congolense infection.the expression of surface membrane antigens on peripheral blood monocytes (pbm) of cattle of the boran and n'dama breeds activated with recombinant cytokines (tnf-alpha and ifn-gamma) and during experimental infection with trypanosoma congolense was investigated using monoclonal antibodies (moabs) and fluorescein-activated cell sorter (facs). the surface antigens investigated were c3bi receptor, major histocompartibility (mhc) ii complex (ia antigen) and two monocyte/macrophage (mphi) differenti ...200011206396
bone marrow response to acute and chronic trypanosoma congolense infection in multimammate rats (mastomys coucha).the femoral bone marrow of multimammate rats (n=90), aged 3-8 weeks, experimentally infected with different doses of trypanosoma congolense was examined by light and electron microscopy. some animals died from trypanosomosis, but groups of 10 were killed at 4-8, 9-16, 20-24, 30, 40, 50 and 60 days post-infection (dpi). in the acute stage of infection (4-8 dpi) the bone marrow invariably showed a striking increase in erythropoiesis, characterized by an increase in the number of mitotic figures an ...200111222012
the relationship between the parasitological prevalence of trypanosomal infections in cattle and herd average packed cell volume.the relationship between prevalence of trypanosomal infections (trypanosoma congolense) and average packed cell volume (pcv) in herds of communally managed adult angoni breed cattle was investigated in four districts of eastern zambia. in all areas, regression analyses showed that the herd average pcv decreased with increasing prevalence of trypanosomal infections. the slope of the equation between average pcv and trypanosome prevalence decreased with increasing prevalence of trypanosomal infect ...200111230826
validation of a polymerase chain reaction assay for monitoring the therapeutic efficacy of diminazene aceturate in trypanosome-infected sheep.the diagnostic performance of a polymerase chain reaction assay (pcr) for monitoring the effectiveness of aceturate diminazene treatment was compared with those of an antibody-detection elisa test and the buffy-coat technique using sheep experimentally infected with either savannah-type or forest-type trypanosoma congolense or t. vivax. within the period of infection, the pcr using specific savannah-type t. congolense primers showed a significant higher diagnostic sensitivity (p<0.05) than the b ...200111230917
demonstration of erythrophagocytosis in trypanosoma congolense-infected goats.anaemia is the most prominent clinical sign of trypanosomosis in domestic animals but little is known about its pathogenesis. this work investigated erythrophagocytosis as the possible cause of anaemia. pathogenic trypanosoma congolense (il3000) was intravenously inoculated into six goats at 3x10(6) trypanosomes per goat. six other goats were maintained as controls. the infection was studied for 10 weeks and parasitaemia, packed cell volume (pcv) and serum protein levels were determined. the amo ...200111230918
morphological changes in the gonads of the sabi ram experimentally infected with trypanosoma congolense.indigenous sabi rams of southern africa were experimentally infected with trypanosoma congolense for 8 and 16 weeks. testes weights (g) were significantly (p<0.05) lower in the infected (249.7+/-26.4) compared to the control (372.63+/-19.4) animals. histopathological and ultrastructural changes included seminiferous tubular atrophy and mononuclear infiltration in the testis, and lesions in the epithelium of the corpus epididymidis (middle segment) as well as spermatozoa in the cauda epididymidis ...200111230958
the analysis of the cross-reactions occurring in antibody-elisa for the detection of trypanosomes can improve identification of the parasite species involved.in africa, the main pathogenic trypanosomes of livestock are trypanosoma vivax, t. congolense and t. brucei. the geographical distributions and hosts of these three species are very similar. as they differ markedly in pathogenicity and epidemiology, however, a species-specific serological test for infection would be very useful for epidemiological studies. the antibody-elisa (ab-elisa) that have been developed for detecting the trypanosoma spp. most commonly infecting livestock give satisfactory ...200111299121
subsite specificity of trypanosomal cathepsin l-like cysteine proteases. probing the s2 pocket with phenylalanine-derived amino acids.the s2 subsite of mammalian cysteine proteinases of the papain family is essential for specificity. among natural amino acids, all these enzymes prefer bulky hydrophobic residues such as phenylalanine at p2. this holds true for their trypanosomal counterparts: cruzain from trypanosoma cruzi and congopain from t. congolense. a detailed analysis of the s2 specificity of parasitic proteases was performed to gain information that might be of interest for the design of more selective pseudopeptidyl i ...200111322895
alternative versus classical macrophage activation during experimental african trypanosomosis.african trypanosomes are extracellular parasites causing sleeping sickness to human or nagana to livestock in sub-saharan africa. to gain insight into factors governing resistance/susceptibility to these parasites, the immune responses in mice infected with a trypanosoma brucei phospholipase c null mutant (plc(-/-)) or its wild type counterpart (wt) were compared. we found that the t. b. brucei mutant inducing a chronic infection triggers the production of type i cytokines during the early stage ...200111334945
detection and identification of trypanosoma of african livestock through a single pcr based on internal transcribed spacer 1 of rdna.primers hybridising with the rdna cistron have previously been evaluated for pcr diagnosis specific for kinetoplastids, and shown to detect and differentiate the trypanosoma brucei complex and trypanosoma cruzi. kin1 and kin2 primers, amplifying internal transcribed spacer 1, were subsequently evaluated for the diagnosis of african livestock trypanosomosis. based on the size of the pcr products obtained, kin primers allowed detection and identification of three trypanosoma congolense types (sava ...200111334950
redefining terms. 200111360884
the incidence of new and the prevalence and persistence of recurrent trypanosome infections in cattle in southwest ethiopia exposed to a high challenge with drug-resistant parasites.a method is described for calculating new infection incidence from monthly field data collected between april 1994 and february 1998 from an average of 770 ethiopian highland zebu cattle maintained under traditional management in the ghibe valley, southwest ethiopia and exposed to a high challenge with drug-resistant parasites. each month cattle with a packed cell volume (pcv)<26% and detected as parasitaemic, or cattle showing clinical signs of trypanosomosis, were treated with diminazene acetu ...200111369308
standardised tests in mice and cattle for the detection of drug resistance in tsetse-transmitted trypanosomes of african domestic cattle.resistance to the drugs used to control african animal trypanosomosis is increasingly recognised as a constraint to livestock production in sub-saharan africa. the most commonly used tests for detection of trypanocidal drug resistance are tests using mice or ruminants, but these suffer from lack of standardisation and hence it may be difficult to compare the results of different investigators. tests in mice are less expensive than tests in ruminants, but while tests in mice they may be useful as ...200111390069
physical and transcriptional organization of the ribosomal rna genes of the savannah-type trypanosoma congolense.ribosomal rna genes have been cloned from the major species of african trypanosomes. complete nucleotide sequence composition of the small subunit (ssu) and portions of the large subunit (lsu) ribosomal rna genes was determined for each of these trypanosome species. in contrast to the situation in trypanosoma brucei, in savannah-type t. congolense the lsu ribosomal rna is cleaved twice, to generate two additional prominent fragments. this leads to the different profiles observed when the rrna mo ...200111411940
unravelling the phylogenetic relationships of african trypanosomes of suids.african trypanosomes of the subgenera nannomonas and pycnomonas have been recorded from both wild and domestic suids. however, complete descriptions of some of these trypanosomes with regard to host range, pathogenicity, transmission and distribution are still lacking. neither the recently described trypanosoma (nannomonas) godfreyi nor trypanosoma (nannomonas) congolense tsavo have been isolated from mammalian hosts, while trypanosoma (pycnomonas) suis remains the rarest of the salivarian trypa ...200111444615
ethno-veterinary medicine: screening of nigerian medicinal plants for trypanocidal properties.trypanosoma congolense and t. brucei bloodstream form parasites were propagated axenically in suitable standard media at 34 degrees c. the effects of 33 plant extracts, fractions and pure compounds were evaluated on two clones of t. brucei and drug-sensitive and multi-drug-resistant clones of t. congolense. the cytotoxic activity of the trypanocidal extracts was also evaluated on calf aorta endothelial cells in vitro. of the extracts tested, 22% killed t. congolense il 1180 at a concentration of ...200111483373
susceptibility of tumour necrosis factor-alpha genetically deficient mice to trypanosoma congolense infection.the tnf-alpha gene on mouse chromosome mmu17 is among the candidates for the trypanosomosis resistance qtl tir1. tir1 has the largest effect of those loci so far detected which influence degree of resistance to murine trypanosomosis caused by trypanosoma congolense infection. we therefore studied the survival to 180 days after challenge with t. congolense of mice that were homozygous and hemizygous with respect to a disruption of the tnf-alpha gene on a > 99% c57bl/6 (resistant) background. we a ...200111489168
drug-resistant trypanosoma congolense in naturally infected donkeys in north omo zone, southern ethiopia.a three-part study was conducted to determine the efficacy of isometamidium chloride in donkey populations naturally infected with trypanosomes in north omo zone, southern ethiopia. in the first, 373 randomly selected donkeys from four villages were examined for trypanosome infections by the dark ground/phase contrast buffy coat technique (bct) in november 1999. the trypanosome prevalence was 18.2% (95% confidence interval (ci): 14.4, 22.5) and trypanosoma congolense was the most common species ...200111511413
in vitro effect of alkaloids on bloodstream forms of trypanosoma brucei and t. congolense.the effect of 34 alkaloids of the piperidine, pyridine, tropane, isoquinoline, indole, quinolizidine, quinoline, purine, and steroidal types on the growth of trypanosoma brucei, t. congolense, and human hl-60 cells was investigated in vitro. berbamine, berberine, cinchonidine, cinchonine, emetine, ergotamine, quinidine, quinine, and sanguinarine showed trypanocidal activities with ed(50) (50% effective dose) values below 10 microm. berberine, emetine, and quinidine were the most active compounds ...200111582539
prevalence and incidence of trypanosomosis in horses and donkeys in the gambia.in a study of the prevalence and incidence of trypanosomosis in horses and donkeys in two regions of the gambia, surveys were carried out at niamina east and bansang south with a high and low to moderate tsetse challenge, respectively. eleven horses and 67 donkeys were sampled monthly from august 1997 to september 1998. blood samples were examined for trypanosomes using the buffy-coat (bc) method and polymerase chain reaction (pcr). three primer sets were used, specific for either trypanosoma vi ...200111587839
immunisation of cattle with cysteine proteinases of trypanosoma congolense: targetting the disease rather than the parasite.in order to test the hypothesis that trypanosome cysteine proteinases (cps) contribute to pathology of trypanosomosis, cattle were immunised with cp1 and/or cp2, the major cps of trypanosoma congolense, and subsequently challenged with t. congolense. immunisation had no effect on the establishment of infection and the development of acute anaemia. however, immunised cattle, unlike control cattle, maintained or gained weight during infection. their haematocrit and leukocyte counts showed a tenden ...200111595229
functional expression of the catalytic domains of two cysteine proteinases from trypanosoma congolense.the catalytic domains of two closely related cysteine proteinases (cp1 and cp2) from trypanosoma congolense, referred to as c1 and c2, were expressed as proforms in escherichia coli (c1) and in the baculovirus system (c1 and c2). while the bacterial expression system did not allow recovery of active c1, the baculovirus system led to secretion of inactive zymogens which could be processed at acidic ph into mature enzymes. active c1 and c2 were purified from serum-free culture supernatants by anio ...200111595230
reversible inhibition of cathepsin l-like proteases by 4-mer pseudopeptides.a library of 121 pseudopeptides was designed to develop reversible inhibitors of trypanosomal enzymes (cruzain from trypanosoma cruzi and congopain from trypanosoma congolense). the peptides share the framework: cha-x1-x2-pro (cha=cyclohexyl-alanine, x1 and x2 were phenylalanyl analogs), based on a previous report [lecaille, f., authié, e., moreau, t., serveau, c., gauthier, f. and lalmanach, g. (2001) eur. j. biochem. 268, 2733-2741]. five peptides containing a nitro-substituted aromatic residu ...200111696372
surface molecules of procyclic forms of trypanosoma simiae and trypanosoma congolense, members of the subgenus nannomonas, share immunodominant carbohydrate epitopes. 200111704280
enhancing effects of anti-cd40 treatment on the immune response of scid-bovine mice to trypanosoma congolense infection.african trypansosomes are tsetse-transmitted parasites of chief importance in causing disease in livestock in regions of sub-saharan africa. previous studies have demonstrated that certain breeds of cattle are relatively resistant to infection with trypanosomes, and others are more susceptible. because of its extracellular location, the humoral branch of the immune system dominates the response against trypanosoma congolense. in the following study, we describe the humoral immune response genera ...200111739556
glycosylphosphatidylinositol-anchored surface molecules of trypanosoma congolense insect forms are developmentally regulated in the tsetse fly.procyclic culture forms of trypanosoma congolense have been shown to express a glutamic acid/alanine-rich protein (garp) on their surface. by labelling t. congolense procyclic culture forms with glycosylphosphatidylinositol (gpi) precursors, we show that garp is bound to the membrane by a gpi anchor and demonstrate the presence of two additional gpi-anchored surface molecules of 24-34 and 58 kda that are abundantly expressed. the 24-34 kda molecule, which is recognised by monoclonal antibodies t ...200211755181
the effects of drug-sensitive and drug-resistant trypanosoma congolense infections on the pharmacokinetics of homidium in boran cattle.two groups of five boran (bos indicus) cattle were infected with one of two populations of trypanosoma congolense; one drug-sensitive (il1180), and one drug-resistant (il3330). the animals were then treated intramuscularly with homidium bromide at a dose rate of 1.0 mg kg(-1) bodyweight 7 days after trypanosomes were detected in the peripheral blood of all the five animals in each group. following treatment of cattle infected with drug-sensitive trypanosomes, parasites could no longer be detecte ...200211835895
recombinant tumor necrosis factor alpha does not inhibit the growth of african trypanosomes in axenic cultures.mice whose tumor necrosis factor alpha (tnf-alpha) genes were disrupted developed higher levels of parasitemia than wild-type mice following infection with trypanosoma congolense il1180 or t. brucei brucei gutat3.1, confirming the results of earlier studies. to determine whether tnf-alpha directly affects the growth of these and other bloodstream forms of african trypanosomes, we studied the effects of recombinant mouse, human, and bovine tnf-alpha on the growth of two isolates of t. congolense, ...200211895989
tetracycline-regulated rna interference in trypanosoma congolense. 200211897138
comparative pathogenicity of three genetically distinct trypanosoma congolense-types in inbred balb/c mice.inbred balb/c mice were infected with three clones of trypanosoma congolense (sam.28.1, dind.3.1 and k60.1a) corresponding, respectively, to the three genetically distinct types (savannah, forest and kilifi) defined within this species, for the purpose of comparing their pathogenicity for a better understanding of the epidemiology of african trypanosomosis. another clone of savannah type, il 3000, was also tested simultaneously to study a probable strain variation. both the clones of savannah ty ...200211900925
trypanosoma congolense: expression of a heat shock protein 70 and initial evaluation as a diagnostic antigen for bovine trypanosomosis.a 69-kda immunodominant protein of trypanosoma congolense was identified as a member of the hsp70 family that is homologous to mammalian bip. we report here the expression of the gene encoding the t. congolense bip in a bacterial system. dot blotting of the truncated recombinant proteins confirmed that bip antigenicity is mainly located in the c-terminal third of the molecule. a recombinant fragment corresponding to this region was used as an antigen in an indirect elisa and an initial evaluatio ...200211971648
distribution of trypanosoma congolense in infected multimammate rats (mastomys coucha): light and electron microscopical studies.in an attempt to determine whether trypanosoma congolense occurs both within and outside the blood vessels in an infected animal host, multimammate rats (mastomys coucha) were infected with t. congolense and samples from spleen, lymph nodes, bone marrow, liver, kidney, lungs, brain, heart, intestines, ovaries and testes were collected. the tissue samples were fixed and processed for light and electron microscopical examination. in all the tissues examined, trypanosomes were found only within the ...200211983307
the african trypanosome cyclophilin a homologue contains unusual conserved central and n-terminal domains and is developmentally regulated.we have cloned and characterized the homologue of cyclophilin a (cypa) from trypanosoma brucei brucei, trypanosoma congolense, trypanosoma evansi and trypanosoma vivax. the 1-kilobase african trypanosome cypa complementary dna contains an open reading frame of 531 base pairs, corresponding to 177 amino acids with a calculated molecular weight of 18,700. the cypa gene is present at one copy/haploid genome in t. brucei, t. congolense and t. vivax and is located on large chromosomes (>3 mb) in t. b ...200212062813
congopain from trypanosoma congolense: drug target and vaccine candidate.trypanosomes are the etiological agents of human sleeping sickness and livestock trypanosomosis (nagana), which are major diseases in africa. their cysteine proteases (cps), which are members of the papain family, are expressed during the infective stages of the parasites' life cycle. they are suspected to act as pathogenic factors in the mammalian host, where they also trigger prominent immune responses. trypanosoma congolense, a major pathogenic species in livestock, possesses at least two fam ...200212108538
azaanthraquinone inhibits respiration and in vitro growth of long slender bloodstream forms of trypanosoma congolense.an ethanolic extract of mitracarpus scaber was found to possess in vitro and in vivo trypanocidal activity against trypanosoma congolense. at a dosage of 50 mg kg(-1) day(-1) in normal saline for 5 days, the extract cured balbc mice infected with t. congolense without any relapse. the isolated active component benz(g)isoquinoline 5,10 dione (azaanthraquinone) (aq) purified from the extract was found to inhibit glucose-dependent cellular respiration and glycerol-3-phosphate-dependent mitochondria ...200212125096
trypanosoma simiae and trypanosoma congolense: surface glycoconjugates of procyclic forms-the same coats on different hangers?organic solvent extraction, reverse-phase high performance liquid chromatography and enzyme-linked immunosorbent assay with surface binding monoclonal antibodies were used to isolate membrane molecules of procyclic culture forms of trypanosoma simiae and trypanosoma congolense. gel electrophoresis of the purified molecules revealed two predominant molecular species from each parasite that were broadly similar yet showed different apparent molecular masses and staining characteristics. the molecu ...200212128053
succinate secreted by trypanosoma brucei is produced by a novel and unique glycosomal enzyme, nadh-dependent fumarate reductase.in all trypanosomatids, including trypanosoma brucei, glycolysis takes place in peroxisome-like organelles called glycosomes. these are closed compartments wherein the energy and redox (nad(+)/nadh) balances need to be maintained. we have characterized a t. brucei gene called frdg encoding a protein 35% identical to saccharomyces cerevisiae fumarate reductases. microsequencing of frdg purified from glycosome preparations, immunofluorescence, and western blot analyses clearly identified this enzy ...200212138089
comparative evaluation of the antibody-detection elisa technique using microplates precoated with denatured crude antigens from trypanosoma congolense or trypanosoma vivax.two fao/iaea indirect enzyme-linked immunosorbent assays (elisa), which use microplates precoated with denatured crude trypanosoma congolense or trypanosoma vivax antigen for detecting anti-trypanosomal antibodies in bovine sera, were evaluated for their sensitivity, specificity and positive and negative predictive values, using 320 ugandan field samples (known negative sera, n = 80; known positive sera, n = 80; cattle herds where control of tsetse and trypanosomosis was practiced, n = 80; and c ...200212166331
comparative pathogenicity of three genetically distinct types of trypanosoma congolense in cattle: clinical observations and haematological changes.the pathology of african bovine trypanosomosis was compared in zebu cattle subcutaneously inoculated with three clones of trypanosomes corresponding to the three genetically distinct types of trypanosoma congolense; savannah-type, west african riverine/forest-type and kilifi-type. all inoculated animals became parasitaemic between 7 and 11 days post-infection (dpi). the savannah-type showed consistently higher levels of parasitaemia and lower packed red cell volume percentages and leukocyte coun ...200212191895
susceptibility of trypanotolerant west african dwarf goats and f1 crosses with the susceptible sahelian breed to experimental trypanosoma congolense infection and interactions with helminth infections and different levels of diet.forty pure west african dwarf (wad) goats and 35 of its f1 crosses with the sahelian breed were used in a multifactorial experimental design to evaluate the effects of an experimental trypanosoma congolense infection and interactions with natural helminth infections and different levels of diet on health and productivity of these two breeds. trypanosome infection caused a severe drop in packed cell volume (pcv), but this was not significantly affected by breed. neither deworming nor diet had any ...200212208040
parasitological prevalence of bovine trypanosomosis in kindo koisha district, wollaita zone, south ethiopia.a cross sectional survey to determine the distribution and prevalence of trypanosomosis was conducted in kindo koisha district, in the wollaita zone in southern ethiopia. a total of 1 008 adult cattle was examined at eight different localities. dark field examination of the buffy coat, as well as stained thin blood film examination and packed cell volume (pcv) evaluation were the diagnostic techniques used. the overall prevalence of bovine trypanosomosis was 15 %. among the positive animals, 108 ...200212233995
non-immune control of trypanosomosis: in vitro oxidative burst of pma- and trypanosome-stimulated neutrophils of boran and n'dama cattle.an in vitro assay that measures the generation of superoxide anions (o2-) was used to assess the level of oxidative burst of phorbol myristate acetate (pma)- and trypanosome-stimulated neutrophils isolated from healthy boran and n'dama cattle, and those infected with trypanosoma congolense. pma stimulation of healthy bovine neutrophils resulted in between 300-400 % increase in o2- generation. neutrophils of boran cattle exhibited slightly higher but insignificant o2- generation capacity than tho ...200212234002
partial structure of glutamic acid and alanine-rich protein, a major surface glycoprotein of the insect stages of trypanosoma congolense.the tsetse fly transmitted salivarian trypanosome, trypanosoma congolense of the subgenus nanomonas, is the most significant of the trypanosomes with respect to the pathology of livestock in sub-saharan africa. unlike the related trypanosome trypanosoma brucei of the subgenus trypanozoon, the major surface molecules of the insect stages of t. congolense are poorly characterized. here, we describe the purification and structural characterization of the glutamic acid and alanine-rich protein, one ...200212368279
infection stage-dependent modulation of macrophage activation in trypanosoma congolense-resistant and -susceptible mice.the contribution of cytokines and chemokines to resistance and susceptibility to african trypanosomiasis remains controversial. in the present study, the levels of type i and type ii cytokines and of the mcp-1 chemokine were compared during the early and late stages of trypanosoma congolense infection in susceptible balb/c and resistant c57bl/6 mice. moreover, the status of macrophage activation was compared in these animals by analyzing the inducible nitric oxide synthase-arginase balance, tumo ...200212379696
identification of trypanosomes in wild animals from southern cameroon using the polymerase chain reaction (pcr).one possible explanation of the maintenance of many historical foci of sleeping sickness in central africa could be the existence of a wild animal reservoir. in this study, pcr was used to detect the different trypanosome species present in wild animal captured by hunters in the southern forest belt of cameroon (bipindi). trypanosomes were also detected by a parasitological method (quantitative buffy coat: qbc). parasite could not be isolated in culture medium (kit for in vitro isolation: kivi). ...200212514949
transferrin coupled azanthraquinone enhances the killing effect on trypanosomes. the role of lysosomal mannosidase.partially purified azanthraquinone (aq) extract from mitracarpus scaber was coupled to bovine transferrin (tf) using azidophenyl glyoxal (apg). the aq-apg-tf conjugate was found to possess an enhanced in vitro trypanocidal activity against trypanosoma congolense and t. brucei brucei. at low concentrations of 0.39-90 mg/ml, the conjugate diminished the growth of t. congolense and t. b. brucei dose dependently at the logarithmic phase. both parasites were more sensitive to aq-apg-tf than to the fr ...200212514955
responses of bovine chimaeras combining trypanosomosis resistant and susceptible genotypes to experimental infection with trypanosoma congolense.west african n'dama cattle have developed a genetic capacity to survive, reproduce and remain productive under trypanosomosis risk. the cellular and molecular bases of this so-called trypanotolerance are not known, but the trait is manifested by the n'dama's greater capacity to control parasitaemia and anaemia development during an infection. in order to examine the role of the haematopoietic system in trypanotolerance, we have exploited the tendency for the placentas of bovine twin embryos to f ...200312531289
experimental african trypanosomiasis: ifn-gamma mediates early mortality.in this study, we demonstrate that kupffer cells in the livers of highly susceptible balb/c mice infected with trypanosoma congolense were loaded with trypanosomal antigen and appeared highly activated. this was associated with an enlarged capillary bed in the livers and decreased blood pressure of these mice towards the terminal stage. blocking of murine il-10 receptor (il-10r)in vivo shortened the survival time of highly susceptible t. congolense-infected balb/c mice. anti-il-10r treatment dec ...200312594839
immunization with a tubulin-rich preparation from trypanosoma brucei confers broad protection against african trypanosomosis.tubulin from trypanosoma brucei was purified to near homogeneity using a protocol which involved treatment with urea with subsequent renaturation and was then used to immunize mice. renatured tubulin further purified by sds-page (denatured), synthetic tubulin peptides (stp), and rat brain tubulin (rbtub) were also used. immunized mice were challenged with t. brucei, trypanosoma congolense or trypanosoma rhodesiense. renatured t. brucei tubulin (ntbtub) induced protection in all mice tested, of w ...200212615162
two trans-sialidase forms with different sialic acid transfer and sialidase activities from trypanosoma congolense.trypanosomes express an enzyme called trans-sialidase (ts), which enables the parasites to transfer sialic acids from the environment onto trypanosomal surface molecules. here we describe the purification and characterization of two ts forms from the african trypanosome trypanosoma congolense. the purification of the two ts forms using a combination of anion exchange chromatography, isoelectric focusing, gel filtration, and subsequently, antibody affinity chromatography resulted, in both cases, ...200312649268
selective pressure can influence the resistance of trypanosoma congolense to normal human serum.resistance and sensitivity to normal human serum (nhs) of trypanosoma congolense, a parasite believed to cause disease in animals only, were investigated in vivo as well as in vitro. our results indicate that like trypanosoma brucei, t. congolense can be grouped into three different phenotypes according to its resistance to nhs. some strains are completely resistant to nhs, like trypanosoma brucei gambiense and the resistant form of trypanosoma brucei rhodesiense. other strains show a very low d ...200212706740
susceptibility of heat shock protein 70.1-deficient c57bl/6 j, wild-type c57bl/6 j and a/j mice to trypanosoma congolense infection.the heat shock protein (hsp) 70.1 gene lies on mouse chromosome 17 among the candidates for tir1, the major quantitative trait locus associated with response to trypanosoma congolense infection. to evaluate whether the hsp70.1 gene is involved in the response, we compared the susceptibility of hsp70.1-deficient c57bl/6 j, resistant wild-type c57bl/6 j and susceptible a/j mice. no differences were observed between hsp70.1-deficient and wild-type c57bl/6 j mice in survival time, levels of parasite ...200312756556
probing cathepsin k activity with a selective substrate spanning its active site.the limited availability of highly selective cathepsin substrates seriously impairs studies designed to monitor individual cathepsin activities in biological samples. among mammalian cysteine proteases, cathepsin k has a unique preference for a proline residue at p2, the primary determinant of its substrate specificity. interestingly, congopain from trypanosoma congolense also accommodates a proline residue in its s2 subsite. analysis of a congopain model showed that amino acids forming its s2 s ...200312837132
a bloodstream trypanosoma congolense sialidase could be involved in anemia during experimental trypanosomiasis.the release of sialic acid (sa) into the serum by trypanosoma congolense infected balbc mice was investigated. a progressive increase in the level of serum sa corresponding to anemia and parasitemia was observed. at maximum parasitemia, the level of total sa from the red blood cells (rbc) dropped by about 45%. solved polynomials revealed an association between free serum sa and rbc-sa. positive roots of quadratics were used to predict complete cleavage of rbc-sa on day 7.01 and maximum accumulat ...200312869528
procongopain from trypanosoma congolense is processed at basic ph: an unusual feature among cathepsin l-like cysteine proteases.congopain, the major cysteine protease from trypanosoma congolense, is synthesized as an inactive zymogen, and further converted into its active form after removal of the proregion, most probably via an autocatalytic mechanism. processing of recombinant procongopain occurs via an apparent one-step or a multistep mechanism depending on the ionic strength. the auto-activation is ph-dependent, with an optimum at ph 4.0, and no activation observed at ph 6.0. after addition of dextran sulfate (10 mic ...200312887059
fizz1 and ym as tools to discriminate between differentially activated macrophages.although it is well-established that macrophages can occur in distinct activation states, the molecular characteristics of differentially activated macrophages, and particularly those of alternatively activated macrophages (aamphi), are still poorly unraveled. recently, we demonstrated that the expression of fizz1 and ym is induced in aamphi as compared with classically activated macrophages (camphi), elicited in vitro or developed in vivo during infection with trypanosoma brucei brucei. in the ...200212892049
serial analysis of gene expression (sage) in bovine trypanotolerance: preliminary results.in africa, trypanosomosis is a tsetse-transmitted disease which represents the most important constraint to livestock production. several indigenous west african taurine bos taurus) breeds, such as the longhorn (n'dama) cattle are well known to control trypanosome infections. this genetic ability named "trypanotolerance" results from various biological mechanisms under multigenic control. the methodologies used so far have not succeeded in identifying the complete pool of genes involved in trypa ...200312927079
cloning and sxpression of mitochondrial heat shock protein 70 of trypanosoma congolense and potential use as a diagnostic antigen.the ability to use mitochondrial heat shock protein 70 (mtp) of trypanosoma congolense as a diagnostic antigen was examined. one cdna clone was obtained by immunoscreening of a t. congolense procyclic form (pcf) cdna library with monoclonal antibody (mab) 10f9. the cdna clone contained an open reading frame of 1,977 bp encoding a polypeptide consisting of 659 amino acids. southern blotting analysis indicated that there were at least three copies of the mtp gene in the haploid genome. interferenc ...200312965928
trans-sialidase-like sequences from trypanosoma congolense conserve most of the critical active site residues found in other trans-sialidases.trypanosoma congolense is the agent of nagana, the trypanosomiasis in african ruminants. trypanosomes express an enzyme called trans-sialidase, which is believed to play an important role in maintaining pathogenicity of the parasites. thus far, only two complete trans-sialidase sequences have been characterised, one from the american trypanosome t. cruzi and one from the african trypanosome t. brucei brucei. although the crystal structure of t. cruzi trans-sialidase has recently been published [ ...200312974389
[acquired immunity to trypanosoma congolense, further observations]. 195313035607
the chemotherapeutic action of phenanthridine compounds. vii. the effect of 2:7-diamino-9-alpha-thienyl-10-methylphenanthridinium chloride (621c47) upon infections with trypanosoma congolense and t. vivax in cattle. 195413149773
studies on ethidium bromide. v. the treatment of cattle infected with resistant strains of trypanosoma congolense. 195413184003
observations on antrycide, fast strains of trypanosoma congolense and t. vivax. 195413189333
studies on the carbohydrate metabolism of trypanosoma congolense. 195413210369
[experimental study of a strain considered as trypanosoma congolense, broden 1904, and transmitted by glossina brevipalpis of mosso, urundi]. 195413218485
[experimental study of a strain called trypanosoma congolense var. urundiense transmitted by glossina brevipalpis of mosso, urundi]. 195413218486
[experimental study of a strain called trypanosoma congolense var. berghei transmitted by glossina brevipalpis of mosso, urundi]. 195413218487
[experimental study of a strain called trypanosoma congolense var. mossoense transmitted by glossina brevipalpis of mosso, urundi]. 195413218488
[variations of virulence of trypanosoma congolense in the mouse after action of cold of -180 degree c]. 195613396517
a new compound active against trypanosoma congolense and t. vivax. 195713400115
observations on experimental trypanosoma congolense infection in the rhesus monkey and the dog. 195613427396
suramin complexes. i. prophylactic activity against trypanosoma congolense in small animals. 195713498662
influence of dietary cod liver oil upon trypanosoma congolense, t. cruzi, t. vivax and t. brucei. 195813537935
the cultivation of trypanosoma congolense in vitro. 195813539721
[mechanism of action of berenil (4,4'-diamidino-diazoaminobenzol) on trypanosoma congolense]. 195813616608
the protection against trypanosomiasis conferred on cattle by repeated boses of antrycide, alone or with trypanosoma congolense. 195813617924
observations on the metabolism of the culture form of trypanosoma congolense. 195913642175
action of certain tetrapyrrole derivatives in experimental trypanosoma congolense infections. 195913645706
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