| a longitudinal study of the susceptibility to normal human serum of a trypanosoma brucei rhodesiense clone non-cyclically passaged in rats. | | 1984 | 6535712 |
| [antigenic variants detected after cyclic transmission of a clone of trypanosoma brucei brucei in trypanosensitive and resistant cattle]. | | 1984 | 6544965 |
| many trypanosome messenger rnas share a common 5' terminal sequence. | the mrnas for different variant surface antigens of trypanosoma brucei start with the same 35 nucleotides. this sequence is encoded by a separate mini-exon, located in a 1.35-kb repetitive element. we have reported that trypanosomes contain many transcripts that hybridize to mini-exon probes, even if they do not make the surface antigens. we show here that these transcripts have the mini-exon sequence at their 5' end; they do not contain other sequences from the mini-exon repeat element and are ... | 1984 | 6547230 |
| antitumor phthalanilides active in acute and chronic trypanosoma brucei brucei murine infections. | a series of phthalanilides and related compounds were tested on a short-term, fulminating, mouse infection of trypanosoma brucei brucei (eatro 110 isolate). the most effective compound was [4,4'-bis (4-methylimidazolin-2-yl)-terephthalanilide] which had a cure rate of 75% at 0.1 mg/kg body weight and 100% at 0.5 mg/kg when administered as three single daily intraperitoneal injections starting 24 hours post-infection. several related phthalanilides and similarly substituted ureas showed definite ... | 1984 | 6548337 |
| localization of the initial steps in alkoxyphospholipid biosynthesis in glycosomes (microbodies) of trypanosoma brucei. | cell fractionation of trypanosoma brucei cultured procyclic stages showed that the key enzyme of glycerol-ether lipid synthesis, dihydroxyacetone-phosphate acyltransferase (ec 2.3.1.42) was exclusively associated with the microbody fraction. these organelles contained in addition 1-acyl glycerol-3-phosphate: nadp+ oxidoreductase (ec 1.1.1.101) and acyl-coa reductase and were capable of utilizing dhap, but not g-3-p, as substrate for lysophosphatidic acid formation. it is concluded that in t. bru ... | 1984 | 6562019 |
| trypanosome variant-specific glycoproteins: a polygene protein family with multiple folding patterns? | infection with the african trypanosomes gives rise to relapsing waves of parasitemia in the host. a predominant population of trypanosomes is present in each wave, and such predominant populations are usually serologically distinct from each other. trypanosomes are covered by an extramembranous, highly antigenic, variant-specific glycoprotein coat that is 15 nm thick. the primary structure of a large portion of the glycoprotein molecule is different in the predominant trypanosome populations of ... | 1984 | 6583708 |
| the intracellular pathway and assembly of newly formed variable surface glycoprotein of trypanosoma brucei. | pulse-chase experiments using l-[35s]methionine suggest that trypanosoma brucei mitat 1.2 variable surface glycoprotein (vsg) synthesized in the rough endoplasmic reticulum, a process that takes 6-8 min, is shuttled to the golgi complex 8 min later. labeling of ultrathin frozen sections with affinity-purified anti-cross-reacting determinant (crd) igg followed by protein a-colloidal gold shows that the crd is localized in the trans-golgi region. cis-golgi is not labeled. vsg, when solubilized by ... | 1984 | 6595657 |
| [campaign against sleeping sickness due to trypanosoma brucei gambiense]. | | 1983 | 6601542 |
| trypanosomal surface coat variant antigen causes polyclonal lymphocyte activation. | variant antigen, the primary component of the surface coat of the salivarian trypanosome, when injected i.v. into mice at dosages encountered during acute infections, produced some of the immunopathogenic phenomena associated with acute african trypanosomiasis. trypanosome-infected and variant antigen-treated mice had splenomegaly caused by proliferation of null cells, b and t lymphocytes, and macrophages. splenic b lymphocytes were nonspecifically activated to produce antibodies to sheep erythr ... | 1983 | 6604754 |
| influence of trypanosoma (t.) brucei brucei infection on delayed-type hypersensitivity to sheep red blood cells in mice. | | 1983 | 6615046 |
| trypanosome antigen-antibody complexes and immunoconglutinin interactions in african trypanosomiasis. | | 1983 | 6618755 |
| human plasma resistant strain of trypanozoon isolated from cattle in gamo gofa. | | 1983 | 6628371 |
| further evidence for the existence of a membrane potential in trypanosoma brucei brucei. | the distribution of 137cs+, in the presence of valinomycin, has been used to measure the magnitude of the membrane potential (delta psi) in bloodstream forms of trypanosoma brucei brucei. values of the delta psi falling in the range -100 mv to -160 mv were observed and the maintenance of this delta psi was sensitive to certain ionophores and protonophores. | 1983 | 6631418 |
| regulation of the growth and differentiation of trypanosoma (trypanozoon) brucei brucei in resistant (c57bl/6) and susceptible (c3h/he) mice. | while trypanosoma brucei brucei gutat 3 were equally infective for c3h/he and for c57bl/6 mice at doses ranging from 5 to 5 x 10(3) organisms and had similar prepatent periods in both strains of mice, infected c57bl/6 mice displayed lower parasitaemia, shorter times to parasite wave remission and survived for a longer time than infected c3h/he mice. parasite growth and differentiation rates and host immune responses were similar for the first 5 days in both strains of mice after infection with 1 ... | 1983 | 6634217 |
| alternative pathway activation of complement by african trypanosomes lacking a glycoprotein coat. | an in vitro culture trypanosoma congolense cell line was established using the mammalian cell feeder layer system. one of the principle characteristics of this parasite was its ability to multiply in culture at 35 degrees c, as an uncoated trypanosome (lacking a glycoprotein surface coat) unlike the original blood stream form from which it was derived. this trypanosome was lysed when incubated in normal human serum in contrast to the parasite which possessed a surface coat. the lytic reaction as ... | 1983 | 6634218 |
| the use of 75-seleno-methionine labelled trypanosoma brucei to measure parasite replication in vivo. | the suitability of 75-se-labelled trypanosomes for the measurement of trypanosome replication rates in vivo was investigated. the principle used to estimate the doubling time of the circulating parasites was the decrease in specific activity of 10(-7) parasites and this was determined both for parasites contained in a whole blood sample and for parasites separated from the blood sample by deae-cellulose chromatography. when two stocks of t. brucei (treu 226, treu 667) were compared it was found ... | 1983 | 6636301 |
| isolation of human serum resistant trypanozoon from cattle in nigeria. | four trypanosome stocks of the subgenus trypanozoon were isolated from a herd of cattle in the jos plateau of nigerian during a study on the epizootiology of trypanosomiasis. one of the stocks was repeatedly highly resistant to normal human serum (blood incubation infectivity test), indicating potential human infectivity. these observations suggest that the domestic cattle might act as reservoir hosts for the causative agent of human trypanosomiasis. | 1983 | 6636302 |
| pathogenesis of trypanosoma brucei infection in deer mice (peromyscus maniculatus). v. macrophage ultrastructure and function. | macrophage numbers increased in the spleen, liver, testes, heart, and kidney of deer mice infected for seven to ten weeks with trypanosoma brucei eatro 110. the macrophages were activated as indicated by their increased size and significant increases in numbers of cell organelles including profiles of rough endoplasmic reticulum (which also increased in length), mitochondria, primary and secondary lysosomes, bundles of golgi's apparatus, and free lysosomes compared to macrophages from control mi ... | 1983 | 6636469 |
| the use of the 2 substituted 5-nitroimidazole, fexinidazole (hoe 239) in the treatment of chronic t. brucei infections in mice. | relapse of chronic t. brucei infections was completely prevented by treating with either diminazene aceturate (berenil) at 40 mg/kg or suramin (germanin) at 20 mg/kg followed by four doses of the 2-substituted 5-nitroimidazole (fexinidazole) (hoe 239). none of these drugs administered singly elicited 100% permanent cures although a high percentage of the mice were cured with four doses of fexinidazole at 250 mg/kg. a single dose of 20 mg/kg suramin followed by four daily doses of 30 mg/kg fexini ... | 1983 | 6636983 |
| comparison of glycolysis in intact and digitonin-permeabilized bloodstream trypomastigotes of trypanosoma brucei. | digitonin has been used to permeabilize bloodstream trypomastigotes of trypanosoma brucei. such permeabilized parasites revealed a fully-functional glycolytic pathway which catabolized glucose and some phosphorylated glycolytic intermediates. glucose-starved bloodstream trypomastigotes revealed saturation kinetics with a glucose km = 0.6 mm and vmax = 150 natom o/min per 10(8) for intact parasites; km = 4 mm and vmax = 100 natom o2/min per 10(8) for permeabilized parasites. glucose oxidation in ... | 1983 | 6642055 |
| are there two classes of vsg gene in trypanosoma brucei? | antigenic variation in the african trypanosomes involves the sequential expression of genes coding for different variant surface glycoproteins (vsgs) (reviewed in refs 1-3). when expression of some vsg genes is switched on, a newly duplicated copy of the expressed gene has been observed within the trypanosome genome, which is not found after the gene's expression is switched off again. the duplicated copy has therefore been called an expression-linked copy (elc). the expression of the gene appea ... | 1983 | 6646202 |
| bromoacetyl-l-carnitine: biochemical and antitrypanosomal actions against trypanosoma brucei brucei. | one of the causative agents of the african trypanosamiases, trypanosoma brucei brucei is able to use high intracellular carnitine concentrations and a high carnitine acetyl transferase (cat) activity to stimulate atp production. this paper reports that a carnitine analogue, bromoacetyl-l-carnitine, is an irreversible inhibitor of cat from t.brucei, non-competitively inhibits carnitine uptake by t.brucei and has a potent in vitro effect against t.brucei motility and infectivity. an in vivo action ... | 1983 | 6651867 |
| instability of the trypanosoma brucei rhodesiense metacyclic variable antigen repertoire. | trypanosoma brucei rhodesiense undergoes antigenic variation in its mammalian host by changing the glycoprotein composing its surface coat. trypanosome clones which have the same repertoire of variable antigen types (vats) are said to belong to the same serodeme. tsetse flies infected with a particular serodeme extrude infective metacyclic trypanosomes which express only a restricted part of this repertoire. as the only known acquired immunity in african trypanosomiasis is vat-specific this limi ... | 1983 | 6656871 |
| natural agglutinins to african trypanosomes. | agglutinins to uncoated culture forms of the african trypanosomes, t. congolense and t.b. brucei were detected in sera from a variety of mammals not exposed to the parasites. the agglutinins in bovine serum were shown to be specific antibodies with opsonic properties selective for the species of trypanosome. these findings suggest a possible role for the glycoprotein coat in preventing access of cross-reacting antibodies to the plasma membrane of african trypanosomes. | 1983 | 6657292 |
| immune mechanisms in c57b1 mice genetically resistant to trypanosoma congolense infection. ii. aspects of the humoral response. | some aspects of the humoral response in trypanotolerant c57b1 mice and susceptible a/j mice were investigated to determine the possible basis of trypanotolerance. when the hepatic uptake of 75se-labelled t. congolense by infected mice was measured as an index of antibody production, it was found that only c57b1 mice could remove circulating labelled parasites, this ability persisting for several weeks after infection. estimation of the immunoglobulin concentrations in both strains of mice showed ... | 1983 | 6657296 |
| treatment with suramin and 2-substituted 5-nitroimidazoles of chronic murine trypanosoma brucei infections with central nervous system involvement. | mice infected with either of two isolates of trypanosoma brucei, gvr 23/1 or gvr 35/1, develop a chronic infection in which trypanosomes are localized in the central nervous system. these infected mice were used to evaluate the efficacy of a combination drug treatment comprising suramin and one of three 2-substituted 5-nitroimidazoles. none of the three 5-nitroimidazoles tested alone, cured mice when administered 21 days after infection. however, it was found that t. brucei gvr 23/1 infections c ... | 1983 | 6659049 |
| the effect of trypanosoma brucei infection on local and systemic antibody responses of rats to nippostrongylus brasiliensis. | adult hooded lister rats were given 5000 nippostrongylus brasiliensis larvae on day 3 or 7 after infection with trypanosoma brucei and a second dose of 5000 nematode larvae 28 days later. a similar number of rats was infected only with n. brasiliensis larvae. comparison of antibody levels in serum and the respiratory and alimentary tracts showed that t. brucei infection influenced both systemic and local antibody responses of rats to n. brasiliensis antigens. after primary infection systemic ant ... | 1983 | 6665865 |
| [behavior of a trypanosoma brucei strain (stib 348c) in mice. 3. histopathological findings in the terminal stage of infection]. | histopathological findings in the terminal stage of the infection of mice and rats with different variants of the trypanosoma brucei brucei stock are described. mice infected with mild variants showed after 12-149 days intense trypanosome colonization of the interstitial connective tissue, especially of the heart muscle, pancreas and choroid plexus, with severe tissue destructions, especially in the pancreas. with longer duration of the infection, round cell infiltrations of the leptomeninx and ... | 1983 | 6665866 |
| molecular characterization of initial variants from the istat i serodeme of trypanosoma brucei. | variant surface glycoproteins (vsgs) were isolated from variant antigen types (vats) of the istat 1 serodeme. molecular weight and isoelectric focusing analysis demonstrate that seven early vsgs possess properties generally attributed to vsgs isolated from other trypanosome serodemes. six of the seven vsgs characterized are distinct from one another, while two (d and 1) appear identical. the presence of vsg specific mrna in corresponding vats was demonstrated by in vitro translation of rna from ... | 1983 | 6674811 |
| genomic organization of trypanosoma brucei variant antigen gene families in sequential parasitemias. | cdna libraries were made from mrna purified from each of seven sequentially isolated variant antigen types (vats) of the istat 1 serodeme. plasmids containing variant surface glycoprotein (vsg) sequences corresponding to each of the isolates were used in southern analyses to examine the genomic organization of vsg nucleotide sequences. in most cases, cells expressing a given vsg were shown to have an extra copy of the corresponding vsg gene. in one case an expression-linked copy (elc) was not de ... | 1983 | 6674812 |
| genomic organization of variant surface glycoprotein genes in trypanosoma brucei procyclic culture forms. | the production of the variant surface glycoprotein coat of bloodstream form african trypanosomes ceases after conversion to the procyclic form. in the bloodstream stage alternate expression of different variant surface glycoprotein genes is responsible for the antigenic variation that occurs during relapse infections in the mammalian host. we have examined procyclic stage populations, derived from different bloodstream variant antigen types, for the two types of genomic alterations associated wi ... | 1983 | 6676354 |
| massive increase in splenic germinal centres of chickens experimentally-infected with trypanosoma brucei brucei. | domestic chickens infected with trypanosoma brucei brucei developed a latent parasitaemia which lasted for one year. six distinct variable antigen types were isolated. spleens from infected birds were studied histologically at different stages of the infection. trypanosome infection produced a progressive increase in the number of germinal centres during the early stages of the infection. peak numbers of germinal centres were reached in the spleen at day 84 after which the numbers were maintaine ... | 1983 | 6685396 |
| repression of glycoprotein synthesis and release of surface coat during transformation of trypanosoma brucei. | the biosynthesis of the variant surface glycoprotein (vsg) and its release from the surface of trypanosoma brucei 427 variant clone mitat 1.4 (117) during in vitro transformation of bloodstream trypomastigotes to procyclic trypomastigotes was investigated. after transfer to the transformation medium at 27 degrees c, vsg synthesis is repressed with a half-time, t1/2 = 30 min. concomitantly vsg-specific mrna is lost suggesting that repression operates at the transcriptional level. the expression-l ... | 1983 | 6688990 |
| indomethacin promotes differentiation of trypanosoma brucei. | the treatment of mice with indomethacin lowered trypanosoma brucei parasitemia 1 to 2 log10 because it quickly promoted the differentiation of rapidly dividing long, slender trypanosomes into short, stumpy forms that do not divide in the mammal but do develop a functional mitochondrion and the ability to infect the tsetse. since natural resistance correlates with the rate of differentiation, this observation may provide important information about factors that control the severity of trypanosomi ... | 1984 | 6690416 |
| trypanocidal 1,3-arylene diketone bis(guanylhydrazone)s. structure-activity relationships among substituted and heterocyclic analogues. | based on the antitrypanosomal activity of 1,3-diacetylbenzene bis(guanylhydrazone) (4) and 2,6-diacetylpyridine bis(guanylhydrazone) (17), a number of substituted and heterocyclic 1,3-arylene diketone bis(guanylhydrazone)s were prepared and tested against trypanosoma brucei infections in mice. a wide range of ed50 values was observed among 5-substituted derivatives of 4. the 5-amino analogue 5 and 5-acetamido analogue 6 were about twice as active as 4. 1,3,5-triacetylbenzene tris(guanylhydrazone ... | 1984 | 6690682 |
| two modes of activation of a single surface antigen gene of trypanosoma brucei. | several genes for variant antigens in trypanosomes are activated by duplicative translocation to a telomeric expression site. a second--nonduplicative--mode of activation is restricted to telomeric antigen genes. we show here that the single telomeric gene for antigen 221 can be activated in both ways. we also show that gene 221 is split and that the 5' 35 nucleotide sequence, common to all surface antigen mrnas, is not encoded within 8.5 kb upstream of the 221 coding region. no major rearrangem ... | 1984 | 6692467 |
| anti-trypanosome specific immune responses in bovids of differing susceptibility to african trypanosomiasis. | a clone of trypanosoma brucei brucei (ditat 1.1) was injected into 32 bovids of various breeds, 11 animals being kept as controls. five animals, simmental-ndama f1 crosses, were extremely sensitive. they showed overt symptoms and one died on day 18 of infection despite treatment with a trypanocidal drug. seven other animals became ill but recovered progressively and cleared the infection. twenty animals, of breeds generally considered to be trypanosensitive as well as ones from trypanotolerant b ... | 1984 | 6693134 |
| resistance of cattle to tsetse-transmitted challenge with trypanosoma brucei or trypanosoma congolense after spontaneous recovery from syringe-passaged infections. | groups of cattle were inoculated intravenously with cloned populations of bloodstream forms of trypanosoma brucei or trypanosoma congolense. all five steers infected with t. brucei iltat 2.1 and six of the eight steers infected with t. congolense il 13-e14 became aparasitemic within 16 and 32 weeks postinfection, respectively. examination of sera from animals infected with t. brucei by indirect immunofluorescence and neutralization assays revealed the presence of antibodies against all the metac ... | 1984 | 6693173 |
| myristylation of the membrane form of a trypanosoma brucei variant surface glycoprotein. | a variant surface glycoprotein (vsg) of the parasitic protozoan trypanosoma brucei was purified following the direct solubilization of trypanosomes in a boiling detergent solution. this material behaved as the amphiphilic membrane form of the glycoprotein previously described (cardoso de almeida, m. l., and turner, m. j. (1983) nature (lond.) 302, 349-352). analysis of this material showed that it contained ester-linked tetradecanoic (myristic) acid. after biosynthetic labeling of trypanosomes w ... | 1984 | 6699005 |
| partial purification and characterization of microtubular protein from trypanosoma brucei. | the tubulin proteins of the parasitic hemoflagellate trypanosoma brucei brucei were purified and characterized. cytoskeletal microtubules of trypanosomes do not disrupt under conditions used to solubilize brain tubulins. trypanosomal tubulins, solubilized by extensive sonication, were partially purified from the crude cell extracts by taxol-mediated polymerization. taxolinduced microtubules were identified by electron microscopy and analyzed biochemically. they consist predominantly of two prote ... | 1984 | 6707021 |
| evolution of a trypanosome surface antigen gene repertoire linked to non-duplicative gene activation. | african trypanosomes activate, one at a time, a large set of genes coding for different variant-specific surface antigens (vsas). these genes have been classed into two groups. in the first group a permanently silent basic gene copy is duplicated and the expression-linked copy (elc) transposed to an expression site located at a chromosome end. the process is a gene conversion which changes a variable stretch of the preceding elc. genes belonging to the second group do not give rise to an additio ... | 1984 | 6709043 |
| parasite development and host responses during the establishment of trypanosoma brucei infection transmitted by tsetse fly. | following inoculation of trypanosoma brucei into large mammals by the tsetse fly a local skin reaction, the 'chancre', develops due to trypanosome proliferation. we have cannulated the afferent and efferent lymphatics of the draining lymph node in goats and examined the onset of a cellular reaction, the emigration of the parasite from the chancre and the development of both antigenic variation and the specific immune response. the chancre first became detectable by day 3 post-infection, peaked b ... | 1984 | 6709396 |
| isolation of phospholipase a1 from trypanosoma brucei. | phospholipase a1 from trypanosoma brucei brucei has been purified 380-fold by column chromatography on phosphatidylcholine-sepharose affinity columns followed by deae-cellulose anion-exchange chromatography and sephacryl s-200 molecular exclusion chromatography. octyl-agarose hydrophobic column chromatography can be substituted for the pc-sepharose column. the molecular weight of trypanosomal plase a1 was found to be 26,000 by sds-polyacrylamide gel electrophoresis. | 1984 | 6710597 |
| ribosomal rna genes of trypanosoma brucei: mapping the regions specifying the six small ribosomal rnas. | there are six small ribosomal rnas in trypanosome ribosomes. srna3 and srna5 of trypanosoma brucei brucei have been partially sequenced. sequence homologies indicate that srna3 is 5.8s rna and srna5 is 5s rna of t. b. brucei. the regions specifying these two, and the remaining four small rnas, have been identified within clones of rrna genes and in the genome. five of the small rnas, 1, 2, 3, 4 and 6, hybridise exclusively within the major rrna gene repeat. a map of the regions specifying these ... | 1984 | 6714673 |
| purification, morphometric analysis, and characterization of the glycosomes (microbodies) of the protozoan hemoflagellate trypanosoma brucei. | trypanosoma brucei glycosomes (microbodies containing nine enzymes involved in glycolysis) have been purified to near homogeneity from bloodstream-form trypomastigotes for the purpose of morphologic and biochemical analysis. differential centrifugation followed by two isopycnic centrifugations in an isotonic percoll and in a sucrose gradient, respectively, resulted in 12- to 13-fold purified glycosomes with an overall yield of 31%. these glycosomes appeared to be highly pure and contained less t ... | 1984 | 6715405 |
| [from cancer cell to trypanosoma and back]. | | 1984 | 6717651 |
| release and purification of trypanosoma brucei variant surface glycoprotein. | conditions affecting the solubilization of variant surface glycoprotein (vsg) from trypanosoma brucei have been investigated. the results obtained form the basis for a convenient and efficient method for vsg purification. vsg release from the cell surface was temperature-dependent, following osmotic lysis at 0 degree c, and was inhibited by low concentrations of zn2+ but not by tosyl-lysine chloromethyl-ketone (tlck), phenylmethylsulfonylfluoride (pmsf), or iodoacetamide. these and other results ... | 1984 | 6725422 |
| pathogenesis of trypanosoma brucei infection in deer mice (peromyscus maniculatus). ultrastructural pathology of the spleen, liver, heart, and kidney. | trypanosoma brucei eatro 110 infection of the deer mice (peromyscus maniculatus) produced moderate to marked lesions in the spleen, liver, heart, and kidney seven to ten weeks after infection. splenic lesions consisted of marked splenomegaly, with infected spleens weighing 25.9 times control spleens. transmission electron microscopy of the sinuses and billroth's cords of the splenic red pulp demonstrated an increased cellularity with greater contact between cells due partly to proliferation of m ... | 1984 | 6730206 |
| pathogenesis of trypanosoma brucei infection in deer mice (peromyscus maniculatus). light and electron microscopic study of testicular lesions. | the results of light and electron microscopic studies demonstrated that trypanosoma brucei infection produced marked testicular degeneration in deer mice (peromyscus maniculatus) with highly significant (p less than 0.001) decreases in testicular weight, seminiferous tubular diameter, and epithelial thickness. lesions in seminiferous tubules consisted of necrosis of spermatids, spermatocytes, and sometimes the spermatogonia. sertoli's cells had marked vacuolation and accumulation of phagocytic m ... | 1984 | 6730207 |
| response of the rat's hepatic drug-metabolizing enzyme system to chemotherapy of trypanosoma b. brucei infections with berenil and suramin. | berenil (4,4-diamidinodiazoaminobenzene-diacetamide acetate) or suramin [sodium salt of 8-(3-benzamido-4-methylbenzamido)-naphthalene-1,3,5-trisulfonic acid] treatment of rats infected with trypanosoma b. brucei enhanced hepatic microsomal aniline hydroxylase and p-aminopyrine n-demethylase activities. while suramin inhibited significantly the activities of cytoplasmic glutamate dehydrogenase and lactate dehydrogenase, berenil had no effect. the kinetic profiles of these enzymes consistently sho ... | 1984 | 6734575 |
| the role of duplication in the expression of a variable surface glycoprotein gene of trypanosoma brucei. | the variable surface glycoprotein (vsg) genes of trypanosoma brucei have been classified into two groups depending upon whether or not duplication of the genes is observed when they are expressed. we report here the observation of duplication apparently linked to expression of the iltat 1.3 gene in the etar 1 trypanosome stock. in the iltar 1 stock, expression of the iltat 1.3 vsg did not involve a new duplication, but instead activation of a preexisting gene copy that had been apparently genera ... | 1984 | 6736139 |
| purification and properties of the membrane form of variant surface glycoproteins (vsgs) from trypanosoma brucei. | variant surface glycoproteins (vsg) of trypanosoma brucei are released in a water soluble form on impairment of membrane integrity. we have previously shown that this release is the result of an enzyme-mediated event which converts the hydrophobic membrane form vsg into the hydrophilic water-soluble form. we now present further details of the methods by which membrane form vsg ( mfvsg ) may be isolated, uncontaminated by water-soluble vsg ( svsg ). the sensitivity to different metal ions of the ... | 1984 | 6737318 |
| identification of an acridine photoaffinity probe for trypanocidal action. | twenty-four acridine derivatives were screened for trypanocidal activity in trypanosoma brucei in order to determine which structural features of the acridine molecule confer maximal antiparasitic activity. the synthesis of several new azidoacridine derivatives are also reported as well as an assessment of their value as possible photoaffinity probes for the study of acridine trypanocidal action. the most effective and selective acridine trypanocides, with and without irradiation, were the 3-ami ... | 1984 | 6737429 |
| trypanosoma brucei: biochemical and morphological studies of cytotoxicity caused by normal human serum. | the biochemical and morphological events which accompany lysis of trypanosoma brucei by normal human serum have been described. the prelytic events include loss of infectivity and rapid cation shifts across the cell membrane. this is followed by cell swelling, fraying of the surface coat of the cell, loss of intracellular organelles, and eventually cell lysis. the data presented are consistent with a colloid osmotic mechanism of lysis induced by irreversible acute damage to the normal permeabili ... | 1984 | 6745390 |
| glycosyltransferase activities in golgi complex and endoplasmic reticulum fractions isolated from african trypanosomes. | highly enriched golgi complex and endoplasmic reticulum fractions were isolated from total microsomes obtained from trypanosoma brucei, trypanosoma congolense, and trypanosoma vivax, and tested for glycosyltransferase activity. purity of the fractions was assessed by electron microscopy as well as by biochemical analysis. the relative distribution of all the glycosyltransferases was remarkably similar for the three species of african trypanosomes studied. the golgi complex fraction contained mos ... | 1984 | 6746739 |
| genetics of resistance to the african trypanosomes. iii. variant-specific antibody responses of h-2-compatible resistant and susceptible mice. | genetically based differences in variant-specific immunity to the african trypanosomes were examined. h-2-compatible inbred mouse strains that differed in relative resistance were infected with trypanosoma rhodesiense clone loutat 1. antibody responses to exposed epitopes of the loutat 1 variant-specific surface glycoprotein (vsg) were measured. relatively resistant b10.br mice (h-2k) made predictable igm antibody responses to the vsg of loutat 1 which were associated with clearance of the louta ... | 1984 | 6747297 |
| a comparison of the glycosomes (microbodies) isolated from trypanosoma brucei bloodstream form and cultured procyclic trypomastigotes. | highly purified glycosomes were isolated from trypanosoma brucei bloodstream forms and cultured procyclic trypomastigotes. a comparison of the specific activities of glycosomal enzymes revealed that glycosomes from insect stages had decreased levels of hexokinase, phosphoglucose isomerase, phospho-fructokinase, fructose-bisphosphate aldolase, glyceraldehyde-phosphate dehydrogenase and phosphoglycerate kinase, but contained increased levels of adenylate kinase, malate dehydrogenase and phosphoeno ... | 1984 | 6749187 |
| ump synthesis in the kinetoplastida. | all six enzymes of pyrimidine biosynthesis de novo have been detected in homogenates of the culture promastigote form of leishmania mexicana amazonensis, the blood trypomastigote form of trypanosoma brucei and the culture epimastigote, blood trypomastigote and intracellular amastigote forms of trypanosoma cruzi. dihydroorotate dehydrogenase is mitochondrial in mammals, but the isofunctional enzyme, dihydroorotate oxidase was found to be cytoplasmic, whereas orotate phosphoribosyltransferase and ... | 1982 | 6753942 |
| the detection of phosphonolipids in the protozoan trypanosoma cruzi. | 2-aminoethylphosphonate was detected in the acid hydrolysates of the phosphonolipids and the lipopeptidophosphoglycan of trypanosoma cruzi, the causative agent of chagas' disease. this finding represents the first evidence of phosphonolipids in a zooflagellate. by comparison, no phosphonolipids were detected in trypanosama brucei, indicating that phosphonolipids are not a ubiquitous feature of the order kinetoplastidia. | 1982 | 6758765 |
| the effects of different eland and waterbuck sera on trypanosoma brucei rhodesiense clones from lion and from man. | | 1982 | 6764401 |
| glycolysis in trypanosoma brucei. | the possibility that the glycosomes present in the bloodstream form of trypanosoma brucei [opperdoes, f. r. and borst, p. (1977) febs lett. 80, 360--364] constitute a separate pool of glycolytic intermediates within the cell was investigated. in titrations of intact cells with digitonin, a differential activation of glycolytic enzymes was observed. enolase, pyruvate kinase and the cell-sap marker alanine aminotransferase were activated at 0.05 mg digitonin per mg protein. the nine glycosomal enz ... | 1980 | 6766864 |
| energized amino acid transport by trypanosoma brucei requires a glycolytic intermediate. | | 1980 | 6772490 |
| polyamine metabolism: a potential therapeutic target in trypanosomes. | alpha-difluoromethylornithine (rmi 71,782), a specific irreversible inhibitor of the first step in polyamine biosynthesis, that is, the formation of putrescine from ornithine by ornithine decarboxylase, cures mice infected with a virulent, rodent-passaged strain of trypanosoma brucei brucei. this parasite is closely related to the trypanosomes that cause human sleeping sickness. the drug, which is remarkably nontoxic, was effective when administered in drinking water or by intubation. the abilit ... | 1980 | 6775372 |
| miconazole: an inhibitor of cyanide-insensitive respiration in trypanosoma brucei. | | 1980 | 6776666 |
| trypanosoma brucei: biochemical and morphological changes during in vitro transformation of bloodstream- to procyclic-trypomastigotes. | | 1981 | 6785103 |
| isolation and characterization of polysomes from trypanosoma brucei. | the isolation of polysomes in bulk from bloodstream forms of trypanosoma brucei is described. the polysomes are active in in vitro protein synthesis in the presence or absence of initiation inhibitors. nascent variant surface antigen (vsa) has been detected on these polysomes using purified radio-iodinated antibody. edta-induced ribosomal sub-units and their large rrna's are characterized. the 26s rrna is nicked to produce 2 molecules which are both smaller than the 19s rrna of the small sub-uni ... | 1980 | 6785709 |
| immune depression and macroglobulinemia in experimental subchronic trypanosomiasis. | the effects of subchronic trypanosomiasis upon immune responses were examined in trypanosoma gambiense infection and in subcurative treatment of t. brucei- and t- equiperdum-infected mice. about 60% of the mice infected with t. gambiense developed a subchronic infection similar to human trypanosomiasis, characterized by the absence of circulating trypanosomes. the animals died between 1 and 12 months after infection with elevated serum immunoglobulin m (igm) levels (16 times the normal level). a ... | 1981 | 6788708 |
| characteristics of the calcium-mediated mechanism activating adenylate cyclase in trypanosoma brucei. | 1. the adenylate cyclase of bloodstream forms of trypanosoma brucei is regulated by ca2+. 2. the ca2+-stimulated activity is not inhibited by trifluperazine, tentatively suggesting that the stimulation may not be mediated by calmodulin. 3. the ca2+-binding site of the receptor regulating the adenylate cyclase is buried within the hydrophobic region of the plasma membrane and is not exposed to either the inner or the outer aqueous-phase bounding the membrane in unstimulated cells. 4. the response ... | 1981 | 6790278 |
| trypanosoma brucei brucei: a systematic screening for alternatives to the salicylhydroxamic acid-glycerol combination. | salicylhydroxamic acid (sham) and glycerol, when administered together, cause destruction of bloodstream forms of trypanosoma brucei brucei, both in vitro and in vivo, but the dose required is exceedingly high. in an attempt to improve the efficacy of this drug combination, we examined the ability of various polyols and hydroxamic acids to substitute for glycerol and sham, respectively. no satisfactory substitute for glycerol was found. the inhibition of the trypanosomal alpha-glycerophosphate o ... | 1981 | 6795501 |
| antagonism by polyamines of the curative effects of alpha-difluoromethylornithine in trypanosoma brucei brucei infections. | | 1981 | 6797437 |
| purine metabolism in trypanosoma brucei gambiense. | | 1982 | 6800408 |
| characteristics of the release of the surface coat protein from bloodstream forms of trypanosoma brucei. | bloodstream forms of the african trypanosomes undergo antigenic variation in their mammalian host. this process involves removal of the existing variant coat protein and its replacement with another. the mechanism by which the surface coat protein is released to the external supporting medium has been shown to depend in vitro specifically on the presence of calcium ions together with the calcium ionophore. a-23187, and to be inhibited by zn2+. release of the surface coat protein was not stimulat ... | 1982 | 6801031 |
| localization of malate dehydrogenase, adenylate kinase and glycolytic enzymes in glycosomes and the threonine pathway in the mitochondrion of cultured procyclic trypomastigotes of trypanosoma brucei. | procyclic culture forms of trypanosoma brucei stock 427 have been screened for the presence of enzymes involved in glycolysis, mitochondrial energy metabolism and threonine degradation. the enzyme activities in the procyclics were compared with those of the blood stream forms. the specific activities of glycolytic enzymes represented 30-70% of the respective levels in the blood stream form, except for hexokinase which was 25-fold reduced. cell fractionation showed that the enzymes involved in th ... | 1981 | 6801509 |
| release of the surface coat from the plasma membrane of intact bloodstream forms of trypanosoma brucei requires ca2+. | | 1982 | 6804262 |
| role of calcium in trypanocidal drug action. | the synergistic effect of serum on the drug combination of salicylhydroxamic acid plus glycerol, which is active against trypanosoma brucei, is due to diffusible calcium ions. the synergistic activity can be removed by dialysis of the serum or by addition of calcium chelating agents. a buffer containing calcium can mimic the synergistic activity of serum. this finding may have important implications in the clinical management of african trypanosomiasis in humans. calcium also has a synergistic e ... | 1982 | 6805075 |
| molecular basis for trypanosome antigenic variation. | | 1982 | 6811137 |
| involvement of the glycosome of trypanosoma brucei in carbon dioxide fixation. | | 1982 | 6811317 |
| ornithine decarboxylase in trypanosoma brucei brucei: evidence for selective toxicity of difluoromethylornithine. | activity of ornithine decarboxylase, the major rate limiting enzyme of polyamine biosynthesis, was determined in bloodstream trypomastigotes of trypanosoma brucei brucei. the enzyme required pyridoxal-5'-phosphate, dithiothreitol and edta for optimal activity. several properties of the enzyme were investigated and compared to the mammalian enzyme. most notably, the parasite enzyme was greater than 60-fold more sensitive to the inhibitor dl-alpha-difluoromethylornithine than its mammalian counter ... | 1982 | 6813460 |
| cryptic stage of sleeping-sickness trypanosome developing in choroid plexus epithelial cells. | electronmicrographs of the choroid plexus from rats infected with trypanosoma brucei rhodesiense showed that trypomastigotes from the perivascular spaces may penetrate and undergo multiple division in the ependymal cells which locally constitute the blood-brain barrier. progressive degeneration of the ependymal cell liberates trypomastigotes back into the perivascular space, from which re-entry into the blood may occur. re-entry to the blood does not take place from any tissues other than the br ... | 1982 | 6814567 |
| tubulin genes are tandemly linked and clustered in the genome of trypanosoma brucei. | we have isolated cdna and genomic clones containing alpha- and beta-tubulin genes from trypanosoma brucei. each clone has been mapped, and the identity of the tubulin genes has been established by cross-hybridization with cloned chicken tubulin genes and by hybridization-selection and translation of trypanosome tubulin mrna. in contrast with the dispersed organization of tubulin genes in other organisms, trypanosome alpha- and beta-tubulin genes are physically linked and clustered in tandem repe ... | 1983 | 6825172 |
| experimental infection with two stocks of trypanosoma brucei gambiense. study of the evolution by elution techniques of tissues. | | 1983 | 6825435 |
| relapsed parasitaemia following chemotherapy of chronic t. brucei infections in mice and its relation to cerebral trypanosomes. | mice infected with trypanosoma brucei can be easily cured using the available trypanocidal drugs, provided treatment is given soon after the infection; however, if infection is allowed to continue for some time then it is extremely difficult to obtain a permanent cure, and after an aparasitaemic period the infection eventually relapses. it has been shown that a relatively small number of infective trypanosomes in the brain have escaped the action of the drug and these are able to replicate and e ... | 1983 | 6825436 |
| chemotherapy, relapses and cns in experimental african trypanosomiasis. | | 1983 | 6825437 |
| studies of choroid plexus involvement in chronic infections of mice with trypanosoma brucei gambiense. | | 1983 | 6825438 |
| dna rearrangements linked to expression of a predominant surface antigen gene of trypanosomes. | | 1983 | 6835363 |
| feeding behaviour of glossina morsitans morsitans infected with trypanosoma vivax, t. congolense or t. brucei. | the feeding behaviour of glossina morsitans morsitans infected with trypanosoma vivax, t. congolense or t. brucei was studied and compared with that of uninfected control tsetse. the following parameters were measured. (1) mean number of feeds taken in 20 consecutive days; (2) mean rate of blood meal intake in microgram/sec of the total days fed; (3) mean weight of blood meal intake/day of the total days fed; (4) mean total blood meal engorgement in 20 days; (5) mean number of probes/day of the ... | 1983 | 6835699 |
| characterisation of trypanosoma (trypanozoon) evansi from camels in kenya using isoenzyme electrophoresis. | forty-nine trypanozoon stocks isolated from camels in five different areas of kenya were screened for isoenzyme patterns of 11 enzymes using thin-layer starch gel electrophoresis. the results were compared with those obtained in other studies with trypanosoma (trypanozoon) evansi stocks from south america, nigeria, sudan and kuwait. most of the kenyan camel stocks were found to be either identical or closely similar to t (t) evansi stocks from elsewhere and were therefore designated t (t) evansi ... | 1983 | 6836172 |
| primary murine bone marrow cultures support continuous growth of infectious human trypanosomes. | the human parasite trypanosoma brucei gambiense grew continuously at 37 degrees c in primary cultures of murine bone marrow. cultured parasites remained virulent for mice. rapid parasite growth coincided with the appearance of adherent adipocyte-epitheloid cell aggregates that also promoted hematopoiesis. this culture system should permit studies of host cell control of trypanosome proliferation, pathogenic effects of trypanosomes on blood cell development, and the relative trypanocidal and marr ... | 1983 | 6836284 |
| selective modification of glutathione metabolism. | glutathione, a tripeptide thiol found in virtually all cells, functions in metabolism, transport, and cellular protection. it participates in the reduction of disulfides and other molecules, and conjugates with compounds of exogenous and endogenous origin. it protects cells against the destructive effects of reactive oxygen intermediates and free radicals. modifications of glutathione metabolism may be achieved by administration of selective enzyme inhibitors, and also by giving compounds that i ... | 1983 | 6836290 |
| cultivation of infective forms of trypanosoma (t.) brucei evansi in a continuous culture system. | | 1983 | 6837097 |
| phagocytosis of trypanosoma brucei rhodesiense by peritoneal macrophages: a study by scanning electronmicroscopy. | phagocytosis of trypanosoma brucei rhodesiense by peritoneal macrophages takes place by seizure of the trypomastigote by either end but usually by the anterior. a lamellar sheath similar to that seen in phagocytosis of the promastigote of leishmania is observed, but it is smaller and does not proceed to envelop the living parasite. the attached trypomastigote becomes pitted and appears to have been killed and partially destroyed before it is completely engulfed. | 1983 | 6842569 |
| comparative analysis of a trypanosoma brucei gambiense antigen gene family and its potential use in epidemiology of sleeping sickness. | | 1983 | 6843593 |
| elaboration of mitochondrial function during trypanosoma brucei differentiation. | | 1983 | 6843594 |
| carbohydrate is linked through ethanolamine to the c-terminal amino acid of trypanosoma brucei variant surface glycoprotein. | the c-terminal amino acid of the variant surface glycoprotein from trypanosoma brucei is glycosylated. for two variant proteins that terminate in an aspartic acid and a serine residue respectively, it was shown that the sugar side chain is linked through ethanolamine to the alpha-carboxy group of the amino acid. | 1983 | 6847613 |
| 13c nuclear magnetic resonance studies of anaerobic glycolysis in trypanosoma brucei spp. | anaerobic glycolysis in trypanosoma brucei spp. has been studied by 13c nmr at 50 and 75.5 mhz. the uptake of [u-13c]glucose by cell suspensions of t. b. brucei was monitored by time-course spectroscopy, and while no anomeric specificity was found, the end-products of glycolysis were confirmed as glycerol and pyruvate together with alanine and dihydroxypropionate. the intermediacy of l-glycerol-3-phosphate was also ascertained. the incorporation of c-1 of [1-13c]glucose and of c-6 of [6-13c]gluc ... | 1983 | 6850078 |
| altered hepatic microsomal drug-metabolizing enzyme activity resulting from experimental infection of rats with trypanosoma b. brucei. | infection of experimental rats with trypanosoma brucei (t. b. brucei) results in a decrease in the activities of aniline hydroxylase, aminopyrine-n-demethylase and a lowering of the level of reduced glutathione in the liver. the activity of cytochrome c reductase remains above normal 50 h after infection. infection of animals previously treated with either phenobarbitone or 3-methylcholanthrene results in a reduction in the specific activity of aniline hydroxylase and aminopyrine-n-demethylase. ... | 1983 | 6851993 |
| phagocytosis of antibody-sensitized trypanosoma brucei in vitro by bovine peripheral blood monocytes. | the interaction between bovine peripheral blood monocytes and trypanosoma brucei organisms in the presence of immune whole serum or specific purified igm or igg1 antibodies from infected cattle was investigated. adherence of antibody-sensitized trypanosomes to freshly isolated monocytes from non-infected animals was not observed, confirming the absence of receptors for igm and igg1 on fresh monocytes. after in-vitro cultivation of the monocytes for at least 3 hr, adherence of igm-sensitized tryp ... | 1983 | 6852873 |
| the incidence of trypanosomiasis in the cattle population situated along the peripheries of the kainji national park in nigeria. | | 1983 | 6858468 |
| size fractionation of trypanosoma brucei dna: localization of the 177-bp repeat satellite dna and a variant surface glycoprotein gene in a mini-chromosomal dna fraction. | we have size-fractionated intact dna from trypanosoma brucei into a major large dna fraction (greater than 350s) and minor middle-sized (60-250s) and small (less than 60s) dna fractions. large dna contains the rrna genes, the basic copy genes for several variant surface glycoproteins (vsgs), including one which lies near a telomer, and the expression-linked copies of the two vsg genes. the middle-sized dna contains at least one vsg gene, but the hybridization of this fraction with probes for the ... | 1983 | 6866765 |
| pathogenesis of trypanosoma brucei infection in deer mice (peromyscus maniculatus): hematologic, erythrocyte biochemical, and iron metabolic aspects. | trypanosoma brucei eatro 110 infection in deer mice (peromyscus maniculatus) produced anemia in 15 of 42 mice between postinoculation days 14 and 70. the infected anemic (ia) mice had significantly higher reticulocyte counts (p less than 0.025), spleen (p less than 0.001) and liver (p less than 0.005) weights, and higher parasitemia than did infected nonanemic (ina) mice. gamma-globulin concentrations of infected mice were markedly increased, and values for ina mice were 10% higher than values f ... | 1983 | 6869960 |