| specific cleavage of pre-edited mrnas in trypanosome mitochondrial extracts. | rna editing in trypanosoma brucei is a posttranscriptional processing event that results in the addition and deletion of uridine residues within several mitochondrial mrnas. we have examined reactions involving pre-edited precursor rnas in vitro. in this study, we report specific cleavage of pre-edited cytochrome b (cyb), cytochrome oxidase subunit ii (coii), and cytochrome oxidase subunit iii (coiii) mrnas when incubated with t. brucei mitochondrial extracts. the pre-edited cyb rna was cleaved ... | 1992 | 1375322 |
| synthesis of mannosylglucosaminylinositol phospholipids in normal but not paroxysmal nocturnal hemoglobinuria cells. | to identify mannosyl (man)-containing intermediates of the human glycoinositol phospholipid (gpi) anchor pathway and examine their expression in paroxysmal nocturnal hemoglobinuria (pnh), mannolipid products deriving from in vitro guanosine diphosphate [3h]man labeling of hela cell microsomes were characterized. the defined gpi species were correlated with products deriving from in vivo [3h]man labeling of normal and (gpi-anchor defective) affected leukocytes. in vitro analyses in hela cells sho ... | 1992 | 1378620 |
| surface epitope variation via mosaic gene formation is potential key to long-term survival of trypanosoma brucei. | trypanosoma brucei evades the immune response of its mammalian host by antigenic variation in the major surface antigen (the variable surface glycoprotein or vsg). we examined the generation of diversity in 4 in vivo-derived antigenically related clones of t. brucei by sequencing vsg cdna from each of the 4 clones and all 5 related genomic copies in the watat 1.1 progenitor organism. each expressed vsg gene was a different mosaic of basic copy genes; 3 were complex mosaics consisting of multiple ... | 1992 | 1380125 |
| trypanosoma brucei mitochondrial ribosomal rna synthesis, processing and developmentally regulated expression. | the steady-state levels of the mitochondrial ribosomal rnas of trypanosoma brucei are repressed in the early bloodstream developmental stage of the parasite and accumulate approximately 30-fold during differentiation to the stage found in the midgut of the insect vector. in order to determine the mechanism regulating this developmental process, we have examined the transcription and processing of the 9s and 12s mitochondrial rrnas of t. brucei. a short-lived rna was detected in pulse labeling ex ... | 1992 | 1381496 |
| identification of nuclear encoded precursor trnas within the mitochondrion of trypanosoma brucei. | rnas that function in mitochondria are typically encoded by the mitochondrial dna. however, the mitochondrial trnas of trypanosoma brucei are encoded by the nuclear dna and therefore must be imported into the mitochondrion. it is becoming evident that rna import into mitochondria is phylogenetically widespread and is essential for cellular processes, but virtually nothing is known about the mechanism of rna import. we have identified and characterized mitochondrial precursor trnas in t. brucei. ... | 1992 | 1385429 |
| trypanosoma brucei glycosomal glyceraldehyde-3-phosphate dehydrogenase genes are stage-regulated at the transcription level. | | 1992 | 1396574 |
| nitric oxide mediates suppression of t cell responses in murine trypanosoma brucei infection. | african trypanosomes induce a generalized state of immunosuppression in their mammalian hosts. one characteristic of this is a suppression of lymphocyte responses to mitogen, which is mediated by suppressor macrophages. we investigated the involvement of nitric oxide in this phenomenon. both peritoneal and splenic cell cultures from infected mice released nitrite and this was inhibitable by ng-monomethyl l-arginine (l-nmma). the release of nitrite correlated with suppressed splenic t cell prolif ... | 1992 | 1396977 |
| characterization of a multi-copy gene for a major stage-specific cysteine proteinase of leishmania mexicana. | lmcpb, a gene from leishmania mexicana that encodes a major cysteine proteinase in the parasite, has been cloned and sequenced. lmcpb is related more to cysteine proteinases from trypanosoma brucei and trypanosoma cruzi than to a previously characterized cysteine proteinase, lmcpa, of l. mexicana. it contains a long c-terminal extension characteristic of similar enzymes of t. brucei and t. cruzi. the gene is multi-copy and tandemly arranged. lmcpb rna levels are developmentally regulated with st ... | 1992 | 1397299 |
| aerobic fermentation of glucose by trypanosomatids. | the consumption of glucose by trypanosomatid protozoa such as trypanosoma brucei, trypanosoma cruzi, leishmania spp., and crithidia spp. is characterized by the excretion of reduced products such as succinate, pyruvate, ethanol, l-alanine, or lactate (depending on the species) not only in anaerobiosis, but also under aerobic conditions. the "aerobic fermentation" of glucose is accompanied by a complete lack, or even a reversal, of the pasteur effect. this peculiar catabolism is mediated by a so- ... | 1992 | 1397837 |
| purification and characterization of listeria monocytogenes phosphatidylinositol-specific phospholipase c. | we have purified to homogeneity the 33-kda phosphatidylinositol-specific phospholipase c (pi-plc) from the culture fluid of listeria monocytogenes, a facultative intracellular pathogen. the protein was overexpressed, and secretion of pi-plc was further enhanced by the addition of divalent cations to the culture medium. the basic protein (pi, approximately 9.4) was complexed with anionic proteins in the crude culture fluid. it bound to deae-sepharose and was eluted from sephacryl s-200 near the v ... | 1992 | 1398918 |
| immunological characterization and intracellular localization of trans-spliceosomal small nuclear ribonucleoproteins in trypanosoma brucei. | polyclonal antibodies were raised against purified protein components of the u2 small nuclear ribonucleoprotein (snrnp) from trypanosoma brucei. through immunoblot and immunoprecipitation analyses three antisera were characterized that reacted specifically with u2 snrnp proteins of molecular weights 40,000 (anti-40k) and 16,500 (anti-16.5k), and with each of four proteins of molecular weights 14,000, 12,500, 10,000, and 8,500 (anti-cp). anti-40k antibodies specifically immunoprecipitated the u2 ... | 1992 | 1400334 |
| a proposed mechanism for promoter-associated dna rearrangement events at a variant surface glycoprotein gene expression site. | the expressed variant cell surface glycoprotein (vsg) gene of the protozoan parasite trypanosoma brucei is invariably found at one of several telomeric vsg gene expression sites (ess). the active es in variant 118 clone 1 is found on a 1.5-mb chromosome, and the promoter region is located more than 45 kb upstream of the vsg gene. we had previously shown that dna rearrangement events occurred in the promoter region, specifically at inactivation of this es (k. m. gottesdiener, h.-m. chung, s. l. b ... | 1992 | 1406660 |
| trypanosoma brucei spliced-leader rna methylations are required for trans splicing in vivo. | the trypanosoma brucei spliced leader (sl) rna donates its 5' leader sequence to all nuclear pre-mrnas via trans rna splicing. the sl rna is a small-nuclear u rna-like molecule which is present in the cell as part of a small ribonucleoprotein particle. however, unlike the trimethylguanosine-capped small nuclear u rnas, the sl rna has a highly modified 5' terminus containing an m7g cap and methylations on the first four transcribed nucleotides. here, we show that incubation of procyclic-form t. b ... | 1992 | 1406666 |
| inhibitory effect of trypanosoma brucei brucei on glossina morsitans midgut trypsin in vitro. | the ability of trypanosoma brucei brucei to inhibit trypsin or trypsin-like enzymes in crude midgut homogenates of glossina morsitans morsitans was studied in vitro. the isolated parasites caused a concentration-dependent decrease in midgut trypsin activity. furthermore, trypanosomes lysed by repeated freeze-thawing had a similar effect on trypsin activity. in both cases, the inhibition by either intact or lysed parasites was partial as revealed by dixon plots. similarly, trypanosome membrane pr ... | 1992 | 1409526 |
| developmental regulation of nuclear gene expression in trypanosoma brucei. | | 1992 | 1410447 |
| high-dose nifurtimox for arseno-resistant trypanosoma brucei gambiense sleeping sickness: an open trial in central zaire. | thirty patients with arseno-resistant trypanosoma brucei gambiense sleeping sickness were treated with high-dose nifurtimox (30 mg/kg/d for 30 d). during treatment, the cerebrospinal fluid (csf) white blood cell (wbc) count decreased in all patients except one (mean csf wbc count before nifurtimox: 117/mm3; after nifurtimox: 25/mm3), and trypanosomes disappeared from the csf of all 9 patients in whom parasites had been demonstrated before nifurtimox. among 25 patients seen at least once after tr ... | 1992 | 1412646 |
| relative efficacy of melarsen oxide compared with mel cy (cymelarsan) when used in combination with difluoromethylornithine in the treatment of trypanosomiasis of the central nervous system. | a comparison was made between the efficacy of mel cy (cymelarsan) and melarsen oxide to cure central nervous system trypanosomiasis in a chronic trypanosoma brucei mouse model. combination treatment with difluoromethylornithine and arsenical was used and it was found that there was only a marginal advantage in using the water-soluble mel cy in terms of the numbers of mice cured. | 1992 | 1412647 |
| the response of pigs experimentally infected with trypanosoma brucei to isometamidium chloride therapy and the relation to nutrition. | growing pigs were placed on feeds with high (group a), medium (b) and low (c) dietary energy and were infected with a virulent stock of t. brucei. eight weeks later, the infected pigs were treated with isometamidium chloride at 1 mg/kg live weight and all pigs were subsequently placed on a high energy diet to investigate their response to therapy. clearance of t. brucei from blood was completed 72h after treatment. there was no evidence of relapsed infection up to eight weeks after treatment. re ... | 1992 | 1413445 |
| effects of infection with trypanosoma brucei brucei on different trimesters of pregnancy in ewes. | the effects of trypanosoma brucei brucei infection during the first, second or third trimesters of pregnancy in 13 ewes were studied. all infected ewes were anaemic with the anaemia being most severe, moderate and least in ewes infected in the second, third and first trimesters, respectively. weight loss occurred in all infected ewes but was most severe in ewes infected in the third trimester. three of the four ewes infected in the first trimester died without aborting while one aborted and late ... | 1992 | 1413452 |
| [serological evidence of the existence of a wild reservoir of trypanosoma brucei gambiense in the pendjari biosphere reservation in the republic of benin]. | in the national park of pendjari, situated in the north-west of benin, 91 wild animals, belonging to seven species, were darted. thick and thin blood smears were examined for trypanosomes and plasma for trypanolytic antibodies against 6 antigenic variants of trypanosoma brucei gambiense. parasites were found in 13.92% and trypanolytic antibodies in 20.88% of the samples. a total of 28.57% of animals were positive by at least one of the two test systems used. morphologically trypanosoma congolens ... | 1992 | 1417158 |
| only the serum-resistant bloodstream forms of trypanosoma brucei rhodesiense express the serum resistance associated (sra) protein. | the trypanosoma brucei species consists of three subspecies. t. b. rhodesiense and t. b. gambiense are human infective forms, while t. b. brucei is lysed upon exposure to the cytotoxic factor in normal human serum. t. b. rhodesiense can however occur as a serum-resistant (r) and as a serum-sensitive form (s). in a study of the molecular basis of serum resistance in t. b. rhodesiense it was shown that in the cloned etar1-repertoire only the serum-resistant variants express specific transcripts, e ... | 1992 | 1417165 |
| mechanisms underlying trypanosome-elicited immunosuppression. | t-cell proliferative responses of lymph node cells are profoundly suppressed during experimental infections of mice with trypanosoma brucei. the active suppression of lymph node t-cell proliferative responses is attributed to the coexistence of at least two unlinked suppressive mechanisms that block different t-cell regulatory steps and operate through different effector mechanisms. the generation of prostaglandin-producing macrophages is entirely responsible for the suppression of il-2 producti ... | 1992 | 1417167 |
| advances in sleeping sickness therapy. | the efficacy and adverse effects of nifurtimox and dfmo in the treatment of sleeping sickness are reviewed. both new substances constitute effective novel therapeutic agents for gambiense sleeping sickness, including melarsoprol-refractory disease. dfmo is not very active in rhodesiense sleeping sickness and experience with nifurtimox in this form of trypanosomiasis is too limited to draw valid conclusions. the toxicity of nifurtimox and dfmo is not negligible. optimum dosage and duration of the ... | 1992 | 1417168 |
| diagnosis of human african trypanosomiasis. | | 1992 | 1417169 |
| the predominant calcimedins from trypanosoma brucei comprise a family of flagellar ef-hand calcium-binding proteins. | the cellular complement of calcimedins was identified in trypanosoma brucei by ca(2+)-dependent association with phenyl-sepharose. predominant calcimedins with molecular mass of 23-26 kda and 44 kda, along with minor calcimedins of 96, 120 and 230 kda, were obtained. the trypanosome calcimedins were unrelated to vertebrate annexins, based upon antibody cross-reactivity and an inability to associate in a ca(2+)-dependent way with phospholipid vesicles comprised of phosphatidylserine or phosphatid ... | 1992 | 1417772 |
| nitric oxide-mediated cytostatic activity on trypanosoma brucei gambiense and trypanosoma brucei brucei. | macrophages collected from bcg-infected mice or exposed in vitro to interferon-gamma plus lipopolysaccharide developed a cytostatic activity on trypanosoma brucei gambiense and trypanosoma brucei brucei. this trypanostatic activity of activated macrophages was inhibited by addition of n-monomethyl-l-arginine, an inhibitor of the l-arginine-nitric oxide (no) metabolic pathway, indicating a role for no as the effector molecule. contrary to trypanosomes treated with n2gas, trypanosomes treated with ... | 1992 | 1426137 |
| inhibition of igm antibody-mediated aggregation of trypanosoma gambiense in the presence of complement. | this paper deals with the immune reaction between trypanosoma gambiense and monoclonal igm mouse antibody at equivalence with or without rabbit complement. antibody-mediated trypanosome clumps formed in the absence of complement, and were readily dissociated by complement to become free. in the presence of complement, on the other hand, t. gambiense were not aggregated by the antibody. free parasites adhered readily to cultured peritoneal macrophages. complement-mediated dissociation of the clum ... | 1992 | 1426139 |
| suppression by trypanosoma cruzi of t-cell receptor expression by activated human lymphocytes. | the immunosuppression that develops during chagas' disease and african sleeping sickness is thought to facilitate survival of the causative agents in their mammalian hosts. whereas a number of manifestations of immunosuppression manifested during the course of these diseases has been reported in patients and animals, the mechanisms by which they are induced remain obscure. an in vitro system in which phytohaemagglutinin (pha)-stimulated human peripheral blood mononuclear (pbmc) were co-cultured ... | 1992 | 1427979 |
| an enzyme-linked immunosorbent assay (elisa) for the detection of trypanosomal antigens in goat serum using a monoclonal antibody. | an igm murine monoclonal antibody (mab) tea 1/23.3.4.6 raised against circulating trypanosome antigens was used in a sandwich elisa to assay trypanosomal antigens in a trypanosome lysate preparation and in sera from goats infected with trypanosoma brucei evansi. as little as 1.25 ug/ml of trypanosomal antigen could be detected by this assay. following infection, trypanosomal antigens were first detected in goat serum 24 hours after the intravenous (i/v) or 6 days after the intramuscular (i/m) in ... | 1992 | 1430240 |
| astrocyte activation correlates with cytokine production in central nervous system of trypanosoma brucei brucei-infected mice. | during the late-stage disease associated with human african trypanosomiasis, caused by infection with either trypanosoma gambiense or t. rhodesiense, parasites invade the central nervous system (cns), eventually leading to development of cns pathology. this can be exacerbated by subcurative chemotherapy. the mechanisms through which the inflammatory processes within the cns are controlled remain unclear. | 1992 | 1434541 |
| characterization of carbohydrate metabolism and demonstration of glycosomes in a phytomonas sp. isolated from euphorbia characias. | phytomonas sp. isolated from euphorbia characias was adapted to sdm-79 medium. cells isolated in the early stationary phase of growth were analyzed for their capacity to utilize plant carbohydrates for their energy requirements. the cellulose-degrading enzymes amylase, amylomaltase, invertase, carboxymethylcellulase, and the pectin-degrading enzymes polygalacturonase and oligo-d-galactosiduronate lyase were present in phytomonas sp. and were all, except for amylomaltase, excreted into the extern ... | 1992 | 1435859 |
| a procyclin-associated gene in trypanosoma brucei encodes a polypeptide related to esag 6 and 7 proteins. | the procyclin genes of trypanosoma brucei encode a family of glycoproteins expressed on the surface of procyclic forms of the parasite. these genes are present at different loci in tandem arrays of two or three copies depending on the strain. it has previously been shown that procyclin genes are transcribed from a promotor immediately upstream of the first procyclin gene in each cluster by an rna polymerase that is resistant to high levels of alpha-amanitin. here we show that additional genes, w ... | 1992 | 1435865 |
| the electrochemical proton gradient in the bloodstream form of trypanosoma brucei is dependent on the temperature. | the membrane potential and ph gradient over the plasma membrane of the protozoan parasite trypanosoma brucei were measured with radioactive indicators in combination with the silicone oil centrifugation technique over a range of temperatures. at 37 degrees c a small membrane potential and ph gradient of similar magnitude, but of opposite polarity, were measured. the resulting electrochemical proton gradient was almost zero. however, when the temperature was lowered from 37 degrees c to 22 degree ... | 1992 | 1435870 |
| the translation initiation site of recombinant trypanosoma brucei ornithine decarboxylase varies with different promoters. | expression of the trypanosoma brucei ornithine decarboxylase (odc) gene in escherichia coli behind the lambda phage pr promoter led to the production of a recombinant enzyme having the same subunit molecular weight as the native enzyme [4]. however, when the same gene is expressed behind the tac promoter or the phoa promoter, the odcs produced by the transformed e. coli have subunit molecular weights approximately 2 kda higher than that of the native enzyme. amino terminal sequencing of the reco ... | 1992 | 1435879 |
| sequence differences between histones of procyclic trypanosoma brucei brucei and higher eukaryotes. | four histones, a, b, c, d from procyclic trypanosoma brucei brucei, which show similarities with the amino acid composition of the core histones h3, h2a, h2b and h4, were isolated and cleaved with endoproteinase glu-c. the fragments were separated by fplc reversed phase chromatography and a subset of the fragments (a5, a9, b6, c8, d3, d9, d11) was subjected to sequence analysis. a 54-71% identity was found in the sequences of the fragment c8 and the c-terminal half of h2b and of three fragments ... | 1992 | 1437281 |
| histone-dna interactions in the chromatin of procyclic trypanosoma brucei brucei. | the dissociation of histone proteins a-d from the chromatin of trypanosoma brucei brucei procyclic culture forms was investigated by removing the proteins from the dna by centrifugation of soluble chromatin through isokinetic sucrose gradients in the presence of nacl. the dissociation of the t. b. brucei histones was compared with that of their higher-eukaryote counterparts h3, h2a, h2b and h4. all four histones of t. b. brucei remained bound to the dna at 500 mm nacl, were partially released at ... | 1992 | 1438135 |
| changes in atrial natriuretic factor and plasma renin activity in dogs infected with trypanosoma brucei. | when beagle dogs were infected with trypanosoma brucei, a marked reduction in the plasma concentration of atrial natriuretic factor (anf) occurred in the terminal stage of the disease during weeks 3 and 4. at the same time there was an increase in plasma renin activity (pra) after infection. ultrastructural studies of the atria of these dogs demonstrated a reduction in anf granules. the changes in anf and pra occurred in association with severe pancarditis and the development of heart failure. b ... | 1992 | 1438145 |
| immunological activities of monoclonal igg1 antibody against trypanosoma gambiense. | the present paper deals with the immune reaction between a monoclonal igg1 antibody and trypanosoma gambiense. the aggregation of trypanosomes, immune adherence to macrophages and protection against infection are associated with the antibody. igg1-mediated clumping of trypanosomes is readily dissociated by the addition of complement. dissociation of the clumped trypanosomes in the equivalence area released approximately fifty percent of previously bound surface antigens. these antigens were capa ... | 1992 | 1439985 |
| a kit for in vitro isolation of trypanosomes in the field: first trial with sleeping sickness patients in the congo republic. | | 1992 | 1440814 |
| structural characterization of a novel class of glycophosphosphingolipids from the protozoan leptomonas samueli. | aqueous phenol extraction of the lower trypanosomatid leptomonas samueli released into the aqueous layer a chloroform/methanol/water-soluble glycophosphosphingolipid fraction. alkaline degradation and purification by gel filtration chromatography resulted in a tetrasaccharide (phosphatidylinositol (pi)-oligosaccharide a), and a pentasaccharide (pi-oligosaccharide b), each containing 2 mol of 2-aminoethylphosphonate and 1 mol of phosphate. nuclear magnetic resonance spectroscopy and fast atom bom ... | 1992 | 1447177 |
| glycosome assembly in trypanosomes: variations in the acceptable degeneracy of a cooh-terminal microbody targeting signal. | trypanosomes compartmentalize most of their glycolytic enzymes in a peroxisome-like microbody, the glycosome. the specificity of glycosomal targeting was examined by expression of chloramphenicol acetyltransferase fusion proteins in trypanosomes and monkey cells. compartmentalization was assessed by cell fractionation, differential detergent permeabilization, and immunofluorescence. the targeting signal of trypanosome phosphoglycerate kinase resides in the cooh-terminal hexapeptide, nrwssl; a ba ... | 1992 | 1447292 |
| human african trypanosomiasis: presence of antibodies to galactocerebrosides. | improvements were made in the immunodetection of anti-galactocerebroside (anti-galc) antibody in sera of patients with human african trypanosomiasis by thin-layer chromatography, enzyme-linked immunosorbent assay, and immunoadsorption. rabbit anti-galc antibodies were used to standardize these techniques and demonstrate their specificity. anti-galc antibodies were found in the sera of 42.8% of 63 patients with human african trypanosomiasis. thirty-four control subjects living in the same endemic ... | 1992 | 1449206 |
| molecular characterization of the trypanothione reductase gene from crithidia fasciculata and trypanosoma brucei: comparison with other flavoprotein disulphide oxidoreductases with respect to substrate specificity and catalytic mechanism. | trypanothione reductase belongs to the family of flavoprotein disulphide oxidoreductases that include glutathione reductases, dihydrolipoamide dehydrogenases and mercuric reductases. trypanothione reductase and its substrate, trypanothione disulphide, are unique to parasitic trypanosomatids responsible for several tropical diseases. the crystal structure of the enzyme from crithidia fasciculata is currently under investigation as an aid in the design of selective inhibitors with a view to produc ... | 1992 | 1453951 |
| affected paroxysmal nocturnal hemoglobinuria t lymphocytes harbor a common defect in assembly of n-acetyl-d-glucosamine inositol phospholipid corresponding to that in class a thy-1- murine lymphoma mutants. | deficient expression of glycoinositol phospholipid (gpi) anchored proteins in affected paroxysmal nocturnal hemoglobinuria (pnh) cells has been traced to a defect in gpi anchor assembly. in a previous study (schubert, j., schmidt, r. e., and medof, m. e. (1993) j. biol. chem., in press) we characterized the biosynthesis of putative man-containing gpi anchor precursors in normal peripheral blood lymphocytes and investigated assembly of these intracellular gpi intermediates in cd48- affected and c ... | 1992 | 1460030 |
| impairment of growth of leishmania donovani by trypanosoma brucei during co-culture. | cells of leishmania donovani in co-culture with trypanosoma brucei, were severely affected in their growth, resulting in swelling and subsequent lysis. similar effects were also observed when crithidia luciliae or phytomonas sp. were co-cultured with t. brucei. direct contact between the cells under investigation and t. brucei was necessary because t. brucei did not hamper the growth of the other trypanosomatids, when separated by a filter with 0.2 microns pore size. examination of this phenomen ... | 1992 | 1461680 |
| characterization by isoenzyme electrophoresis of trypanozoon stocks from sleeping sickness endemic areas of south-east uganda. | an epidemic of sleeping sickness, which started in 1976 in a focus within the county of luuka in central busoga, has spread to cover the three districts of busoga and large parts of the neighbouring districts of tororo and mukono. forty-three isolates of the subgenus trypanozoon from busoga and tororo (27 from man, 9 from cows, 2 from pigs and 5 from tsetse flies) were compared by thin-layer starch-gel electrophoresis for seven enzymes. thirty zymodemes were identified; 17 of them were found cir ... | 1992 | 1464150 |
| transgenic mice expressing human apolipoprotein a-i have sera with modest trypanolytic activity in vitro but remain susceptible to infection by trypanosoma brucei brucei. | although trypanosoma brucei brucei fatally infects livestock in much of sub-saharan africa, humans are innately resistant to infection, apparently because high-density lipoproteins (hdl) in human serum lyse this unicellular protozoan parasite. recently, we demonstrated that purified human apolipoprotein (apo) a-i, the major protein (m(r) 28,016) constituent of hdl, had full trypanolytic activity in vitro whereas the apoa-i of cattle and sheep was non-lytic. in the present study, we have sought t ... | 1992 | 1464747 |
| stereoselective synthesis of glycobiosyl phosphatidylinositol, a part structure of the glycosyl-phosphatidylinositol (gpi) anchor of trypanosoma brucei. | o-alpha-d-mannopyranosyl-(1-->4)-o-2-amino-2-deoxy-alpha-d-glucopyranosy l- (1-->6)-1d-myo-inositol 1-(1,2-di-o-myristoyl-sn-glycer-3-yl hydrogen phosphate), a part structure of the glycosyl-phosphatidylinositol (gpi) anchor of trypanosoma brucei, was synthesised efficiently by the phosphonate approach. the glycobiosylinositol core was prepared in a stereocontrolled manner from 1d-2,3,4,5-tetra-o-benzyl-1-o-(4-methoxybenzyl)-myo-inositol, tert-butyldimethylsilyl 2-azido-3,6-di-o-benzyl-2-deoxy-a ... | 1992 | 1468082 |
| bidirectional signals between trypanosoma brucei brucei and dorsal root ganglion neurons. | the extracellular haemoflagellate trypanosoma brucei brucei releases a factor, which can induce cd8+ t-cells to produce interferon-gamma. interferon-gamma derived from these cells promotes proliferation of the trypanosomes. we now report that these trypanosomes can interact with small neurons in cultures of rat dorsal root ganglia, which contain an interferon-gamma like immunoreactive molecule. cultures of dorsal root ganglia were able to promote the proliferation and survival of the trypanosome ... | 1992 | 1469461 |
| isolation, partial amino acid sequence, and cellular distribution of heat-shock protein hsp98 from neurospora crassa. | hsp98 is one of the most prominent proteins synthesized during the heat-shock response of neurospora crassa. we purified hsp98 and determined the amino acid sequence of two overlapping peptides obtained by cyanogen bromide cleavage. this 28 amino acid sequence from hsp98 has 75% homology with a region of the clpb protein of escherichia coli and 86% homology to a 96-kda protein of trypanosoma brucei. it also has 71% homology to hsp104 of saccharomyces cerevisiae. hsp98 was enriched in the microso ... | 1992 | 1472534 |
| stereoselective total synthesis of the glycosyl phosphatidylinositol (gpi) anchor of trypanosoma brucei. | the total synthesis of o-(o-[6-o-(2-aminoethylphosphono)-alpha-d-mannopyranosyl]-(1-->2)- o-alpha- d-mannopyranosyl-(1-->6)-o-[o-alpha-d-galactopyranosyl-(1-->6)-alpha-d- galactopyranosyl-(1-->3)]-o-alpha-d-mannopyranosyl-(1-->4)-2-amino-2-deo xy- alpha-d-glucopyranosyl)-(1-->6)-[1-o-(1,2-dimyristoyl-sn-glycero-3-phosp hono) - 1d-myo-inositol], the gpi anchor of trypanosoma brucei was achieved for the first time. the core structure of the gpi molecule, the glycoheptaosyl part, was constructed in ... | 1992 | 1473115 |
| glucose transport in crithidia luciliae. | the glucose analogue, 2-deoxy-d-glucose, was used to characterise the glucose transport system in crithidia luciliae choanomastigotes. uptake was temperature dependent with a q10 of 2, and saturable with a km of 0.22 mm and vmax of 5.5 nmol min-1 (mg protein)-1 at 23 degrees c. preloaded cells showed rapid exchange of intracellular 2-deoxy-d-glucose when incubated with extracellular d-glucose or 2-deoxy-d-glucose but little exchange with l-glucose. the substrate specificity of the uptake was stu ... | 1992 | 1474988 |
| transient inhibition of protein synthesis accompanies differentiation of trypanosoma brucei from bloodstream to procyclic forms. | it has been widely believed that bloodstream forms of trypanosoma brucei must be first transformed into intermediary and/or short-stumpy forms in the bloodstream of the mammalian host before differentiation to the procyclic culture form can occur. in our recent studies, the pleomorphic t. brucei strain treu667 was found to differentiate directly from the long-slender bloodstream form to the procyclic form in cunningham's medium at 26 degrees c [7]. in the present investigation, the same was foun ... | 1992 | 1474991 |
| a high molecular mass phosphoprotein defined by a novel monoclonal antibody is closely associated with the intermicrotubule cross bridges in the trypanosoma brucei cytoskeleton. | the main component of the cell body cytoskeleton of trypanosoma brucei is the highly organised array of stable, subpellicular microtubules on the cytoplasmic face of the plasma membrane. although several microtubule associated proteins (maps) have been shown to be associated with this array, the mechanisms by which individual microtubules interact with one another and with the membrane are still largely undetermined. in this study we have used the t. brucei cytoskeleton as a complex immunogen fo ... | 1992 | 1478963 |
| putrescine activated s-adenosylmethionine decarboxylase from trypanosoma brucei brucei. | trypanosoma brucei brucei contained a s-adenosyl-l-methionine decarboxylase (adometdc) strongly activated by putrescine. the enzyme was also activated to a lesser extent by cadaverine and 1,3-diaminopropane. spermidine and spermine had no effect on basal activity of the enzyme. however, they interfered with putrescine activation of trypanosomal adometdc. the trypanosomal enzyme could not be precipitated with antiserum against human adometdc. the trypanosomal adometdc enzyme subunit was labeled b ... | 1992 | 1480164 |
| the relationship of variable antigen expression and population growth rates in trypanosoma brucei. | the relationship between variable antigen type (vat) expression and trypanosome growth rates was investigated. growth rates in mice were compared between pairs of cloned trypanosome populations, each of which homogeneously expressed a different vat. all three pairwise combinations of gutats (glasgow university trypanozoon antigen types) 7.3, 7.4 and 7.5 were analysed twice and all three combinations of gutats 8.2, 8.3 and 8.4 were compared once. the lines expressing different vats were of the sa ... | 1992 | 1480602 |
| cure of murine trypanosoma brucei rhodesiense infections with an s-adenosylmethionine decarboxylase inhibitor. | the compound 5'-([(z)-4-amino-2-butenyl]methylamino)-5'-deoxyadenosine (mdl73811), a potent inhibitor of s-adenosylmethionine decarboxylase, was effective in mice against six of eight clinical isolates of trypanosoma brucei rhodesiense, the causative agent of east african sleeping sickness. in combination with the ornithine decarboxylase inhibitor dl-alpha-difluoromethylornithine (dfmo; ornidyl), mdl73811 acted synergistically to cure seven of eight infections. mdl73811 was effective when given ... | 1992 | 1482141 |
| energization-dependent ca2+ accumulation in trypanosoma brucei bloodstream and procyclic trypomastigotes mitochondria. | the permeabilization of trypanosoma brucei procyclic and bloodstream trypomastigotes with digitonin permitted the quantitative estimation of a mitochondrial membrane potential of the order of 130-140 mv, in both forms, using safranine o. dependence on substrate oxidation and response of the procyclic mitochondrial membrane potential to phosphate, fccp, valinomycin, and ca2+ indicate that these mitochondria behave similarly to vertebrate mitochondria regarding the properties of their electrochemi ... | 1992 | 1484549 |
| endocytosed transferrin in african trypanosomes is delivered to lysosomes and may not be recycled. | it has been shown in mammalian systems that the passage of transferrin-colloidal gold (tf-au) through the endocytic system is influenced by the size of the gold colloid (neutra, m. r. et al., j. histochem. cytochem. 33, 1134-1144 (1985); woods, j. w. et al., eur. j. cell biol. 50, 132-143 (1989)). however, in both trypanosoma brucei brucei and trypanosoma congolense, widely varying sizes of tf-au (tf-au5 and tf-au15) have been shown to proceed to lysosomes (webster, p., eur. j. cell biol. 49, 29 ... | 1992 | 1493805 |
| [treatment of sleeping disease caused by trypanosoma brucei gambiense with alpha-difluoromethylornithine (dfmo) in a rural hospital in zaire]. | the authors report the results of 32 patients with sleeping sickness due to trypanosoma brucei gambiense treated with dfmo (dl-alpha-difluoromethylornithine), an inhibitor of polyamine biosynthesis. between those patients, there were 5 new cases, 1 reinfection, and 26 cases with a primary, a secondary resistance or a relapse. 26 cases got dfmo only per os, but six others received first dfmo for two weeks by the intravenous way, followed by three weeks of dfmo per os. the secondary effects were n ... | 1992 | 1494306 |
| identification of an acute-phase reactant in murine infections with trypanosoma brucei. | a 42-kda protein appeared at a much higher concentration in plasma from trypanosoma brucei-resistant (c57bl/6) mice after infection than in plasma from trypanosome-susceptible (c3h/he) mice. this protein was purified by sequential steps of gel filtration, protein a-sepharose affinity chromatography, isoelectric focusing, and ammonium sulfate precipitation. the purified protein was identified as a subunit of the acute-phase reactant haptoglobin. causes of elevated plasma haptoglobin and its impli ... | 1992 | 1500201 |
| characterisation of melarsen-resistant trypanosoma brucei brucei with respect to cross-resistance to other drugs and trypanothione metabolism. | an arsenical resistant cloned line of trypanosoma brucei brucei was derived from a parent sensitive clone by repeated selection in vivo with the pentavalent melaminophenyl arsenical, sodium melarsen. the melarsen-resistant line was tested in vivo in mice against a range of trypanocidal compounds and found to be cross-resistant to the trivalent arsenicals, melarsen oxide, melarsoprol and trimelarsen (33, 67 and 122-fold, respectively). a similar pattern of cross-resistance was found in vitro usin ... | 1992 | 1501641 |
| the interaction of arsenical drugs with dihydrolipoamide and dihydrolipoamide dehydrogenase from arsenical resistant and sensitive strains of trypanosoma brucei brucei. | d,l-dihydrolipoamide and d,l-dihydrolipoic acid react to form stable complexes with melarsen oxide with association constants of 5.47 x 10(9) and 4.51 x 10(9) m-1, respectively. these complexes possess 6-membered cyclic dithioarsenite rings which are 10-fold less stable than the 5-membered rings found in the trypanocidal drugs melarsoprol and trimelarsen, but 500-fold more stable than the 25-membered macrocyclic ring formed between melarsen oxide and dihydrotrypanothione. l-lipoic acid concentra ... | 1992 | 1501642 |
| the impact of human immunodeficiency virus infection on the epidemiology and treatment of trypanosoma brucei gambiense sleeping sickness in nioki, zaire. | to determine if there is an association between human immunodeficiency virus type 1 (hiv-1) infection and trypanosoma brucei gambiense sleeping sickness, all incident cases of trypanosomiasis and a control group of blood donors presenting to the same rural hospital in zaire were tested for anti-human immunodeficiency virus type 1 (anti-hiv-1) antibodies. there was no significant difference in the prevalence of hiv-1 infection between the two groups (7 of 220, [3.2%] for the incident cases and 8 ... | 1992 | 1503182 |
| a developmentally regulated cysteine proteinase gene of leishmania mexicana. | we have isolated a gene encoding a previously unreported class of trypanosomatid cysteine proteinase (cp) from the protozoan parasite leishmania mexicana. the single-copy gene (lmcpa) [corrected]. has several unusual features that distinguish it from cp genes cloned from the related species trypanosoma brucei and trypanosoma cruzi. these include a shorter c-terminal extension of only 10 amino acids and a three-amino-acid insertion, glyvalmet, close to the predicted n-terminus of the mature prote ... | 1992 | 1508041 |
| purification of sn-glycerol-3-phosphate dehydrogenase from trypanosoma brucei brucei. | a protein has been purified from the membranes of bloodstream forms of trypanosoma brucei brucei. the purified material contained a single polypeptide chain of molecular mass 67 kilodaltons as judged by sodium dodecyl sulfate-polyacrylamide gel electrophoresis; under "native" conditions it migrated through a sephacryl s-300 column with a similar molecular mass. the purified protein catalysed electron transfer from sn-glycerol 3-phosphate to oxygen with the subsequent formation of water. electron ... | 1992 | 1510824 |
| the in vitro and in vivo effects of mefloquine on trypanosoma brucei brucei. | blood stream forms of trypanosoma brucei brucei were grown over mouse kidney (mk) cells in minimum essential medium with various concentrations of mefloquine. the drug was observed to inhibit multiplication of the parasites in vitro. groups of male albino mice were treated with mefloquine at 24, 48 and hours after t. b. brucei infection. mefloquine at 0.03 mg/kg body weight administered for 4 consecutive days cleared the infection. no trypanosomes were detected in the blood of these mice for 90 ... | 1992 | 1512455 |
| in vivo import of firefly luciferase into the glycosomes of trypanosoma brucei and mutational analysis of the c-terminal targeting signal. | the compartmentalization of glycolytic enzymes into specialized organelles, the glycosomes, allows the bloodstream form of trypanosoma brucei to rely solely on glycolysis for its energy production. the biogenesis of glycosomes in these parasites has been studied intensively as a potential target for chemotherapy. we have adapted the recently developed methods for stable transformation of t. brucei to the in vivo analysis of glycosomal protein import. firefly luciferase, a peroxisomal protein in ... | 1992 | 1515676 |
| purification and characterization of a novel sialidase found in procyclic culture forms of trypanosoma brucei. | a membrane-bound sialidase (ec 3.2.1.18) was found in procyclic trypomastigotes of trypanosoma brucei. the mammalian stage bloodstream form, however, displayed no sialidase activity. this sialidase is an integral surface protein, linked to the membrane via a glycosylphosphatidylinositol anchor. after osmotic lysis and solubilization with triton cf-54, the enzyme was purified 1900-fold by gel filtration and ion exchange chromatography. its size, as determined by conventional and high-performance ... | 1992 | 1518530 |
| chemotherapy of cns-trypanosomiasis: the combined use of diminazene aceturate or pentamidine with dl-alpha-difluoromethylornithine (dfmo). | the chemotherapy of cns-trypanosomiasis with dl-alpha-difluoromethylornithine (eflornithine, dfmo) with the diamidine, pentamidine (lomidine) or diminazene aceturate (berenil) was examined using the mouse model for cns-trypanosomiasis. although combined dfmo/pentamidine therapy can give complete cures, one or more doses of 100 mg/kg pentamidine was required with continuous administration of dfmo for 14-16 days, and even this treatment failed to cure the mice in a repeat experiment. diminazene ac ... | 1992 | 1519020 |
| pharmacomodulations on new organometallic complexes of ir, pt, rh, pd, os: in vitro and in vivo trypanocidal study against trypanosoma brucei brucei. | new organometallic complexes have been synthesized by association of an active organic molecule with a metallic element such as pt, rh, ir, pd, os. their trypanocidal activity was studied in vitro and in vivo against t. b. brucei. the more active compounds were pentamidine derivatives. the ir- cod-pentamidine complex, and iridium (i) cationic and organometallic complex showed and in vitro activity at 60 micrograms/l. moreover, all infected mice were cured by this compound subcutaneously administ ... | 1992 | 1519021 |
| decrease of testosterone level during an experimental african trypanosomiasis: involvement of a testicular lh receptor desensitization. | to investigate gonadal disorders and changes of the testicular receptors occurring during the sleeping sickness disease (african trypanosomiasis), an experimental model was developed with 10-month-old rats infested by bloodstream forms of two variants of trypanosoma brucei brucei (antat 1.1 a and antat 1.8). at the acute phase, three days after inoculation, the animals were sacrificed for estimating the serum levels of lh and testosterone and the number of testicular lh receptors. considering a ... | 1992 | 1519428 |
| trypanosoma brucei brucei: in vitro production of metacyclic forms. | an in vitro method has been established to obtain metacyclic form populations of trypanosoma brucei brucei. trypanosome populations containing more than 98% of metacyclic forms were obtained from cultures which were: 1) initiated with bloodstream forms in primary cultures in the presence of microtus montanus embryonic fibroblast-like cells (feeder cell layers); 2) maintained in glucose-free eagle's minimum essential medium supplemented with 10 mm l-proline, 2 mm l-glutamine and 20% (v/v) fetal b ... | 1992 | 1522545 |
| codon usage in giardia lamblia. | a codon usage table for the intestinal parasite giardia lamblia was generated by analysis of the nucleotide sequences of eight genes comprising 3,135 codons. codon usage revealed a biased use of synonymous codons with a preference for nnc codons (42.1%). the codon usage of g. lamblia more closely resembles that of the prokaryote halobacterium halobium (correlation coefficient r = 0.73) rather than that of other eukaryotic protozoans, i.e. trypanosoma brucei (r = 0.434) and plasmodium falciparum ... | 1992 | 1522548 |
| diversity of complement-mediated immune reaction to trypanosoma gambiense. | intact and papain-treated trypanosoma gambiense clone populations, each expressing special antigens on their cell surfaces, were mixed with rabbit antiserum in the presence of complement. two distinct types of immune reaction between trypanosomes and antisera were observed: clumping followed by dissociation (cd) and inhibition of aggregation (ia). special antigens on the cell surface of trypanosomes exposed after papain digestion are implicated in both types of immune reaction. ia was considered ... | 1992 | 1523485 |
| cystatin-like cysteine proteinase inhibitors of parasitic protozoa. | a new method has been developed for detecting cystatins and other cysteine proteinase inhibitors. the method, which involves protein separation by sds-page followed by a cysteine proteinase overlay step, is more sensitive than previously reported techniques: as little as 1 ng of recombinant human cystatin c can be detected and cysteine proteinase inhibitors could also be detected in complex protein mixtures such as bovine foetal serum. the method has been used to show, for the first time, cystei ... | 1992 | 1526466 |
| comparison of the cytolytic effects in vitro on trypanosoma brucei brucei of plasma, high density lipoproteins, and apolipoprotein a-i from hosts both susceptible (cattle and sheep) and resistant (human and baboon) to infection. | the african trypanosome, trypanosoma brucei brucei causes a fatal wasting disease in livestock but does not ordinarily infect humans, apparently because this unicellular parasite is lysed by high density lipoproteins (hdl) in human serum. to assess whether there is a specific active constituent in trypanolytic hdl, we have systematically compared the cytotoxic action on t.b.brucei in vitro of native and delipidated hdl, and of individual apolipoproteins, from nonpermissive hosts (human and baboo ... | 1992 | 1527475 |
| high-efficiency clonal growth of bloodstream- and insect-form trypanosoma brucei on agarose plates. | this report describes a method for growing both bloodstream- and procyclic-form trypanosoma brucei as colonies on agarose plates. procyclic colonies, which took 2 weeks to develop, grew with approximately 17% plating efficiency on sdm-79/0.65% agarose supplemented with 20% (vol/vol) conditioned medium. bloodstream forms were adapted to in vitro growth in liquid hmi-9 medium and then spread on hmi-9/0.65% agarose plates, where they grew to visible colonies in 3-5 days. plating efficiencies were f ... | 1992 | 1528898 |
| irreversible inhibition of s-adenosylmethionine decarboxylase of trypanosoma brucei brucei by s-adenosylmethionine analogues. | s-adenosylmethionine analogues designed as active-site directed inhibitors were tested in vitro for their effects on s-adenosylmethionine decarboxylase (adometdc) of trypanosoma brucei brucei. these analogues contained a tertiary nitrogen atom in place of the sulfonium and had a side chain of variable length ending in a reactive group (hydrazino-, aminooxy-, hydrazido- or a methylnitrosourea). the hydrazino- derivatives were the most potent inhibitors with ic50 values in the range of 40-100 nm. ... | 1992 | 1530659 |
| identification of two distinct galactosyltransferase activities acting on the variant surface glycoprotein of trypanosoma brucei. | variant surface glycoproteins (vsgs) of trypanosoma brucei contain two distinct glycosylation sites: (1) n-linked glycans within the protein portion of the molecules, and (2) the glycosyl-phosphatidylinositol (gpi) membrane anchor. since galactose residues show uncommon alpha-glycosidic linkages in the gpi membrane anchor, we were prompted to investigate galactosylation of the gpi anchor. on comparing a trypanosome clone galactosylated exclusively in n-glycans (clone mitat 1.5) with clones galac ... | 1992 | 1533512 |
| characteristics of the binding of human and bovine high-density lipoproteins by bloodstream forms of the african trypanosome, trypanosoma brucei brucei. | bloodstream forms of trypanosoma brucei brucei are unable to synthesize cholesterol but appear to bind and take up plasma low-density lipoproteins (ldl) from their host. whether cholesterol homeostasis of this unicellular parasite also requires interactions with host high-density lipoprotein (hdl) particles is unknown. equilibrium binding of radioiodinated apolipoprotein e-depleted human hdl3 (d = 1.125-1.21 g/ml) and bovine hdl (d = 1.063-1.21 g/ml) by t.b.brucei was rapid (less than 30 min) at ... | 1992 | 1536861 |
| atp-dependent saccharomyces cerevisiae phospho enol pyruvate carboxykinase: isolation and sequence of a peptide containing a highly reactive cysteine. | saccharomyces cerevisiae phospho enol pyruvate carboxykinase (ec 4.1.1.49), inactivated by n-(iodoacetyl)-n'-(5-sulfo-1-naphthyl)ethylenediamine, incorporated 0.95 mol of the fluorescent moiety per mol of enzyme subunit. reagent incorporation was completely protected by the presence of adp plus mncl2. the labeled protein was digested with trypsin after carboxymethylation. two labeled peptides were isolated by reverse-phase high-performance liquid chromatography and were sequenced by gas-phase au ... | 1992 | 1540632 |
| a phosphoglycerate kinase-related gene conserved between trypanosoma brucei and crithidia fasciculata. | trypanosoma brucei and crithidia fasciculata both contain three different phosphoglycerate kinase (pgk) genes, a, b and c, in a tandem array. the genes b and c encode the major pgks: the cytosolic and glycosomal pgks, respectively. the pgk-a genes of both trypanosomatid species encode open reading frames related to pgk, which have most active site residues conserved, but contain an insert of 80 amino acids at approximately position 80 of the 420 amino acids average pgk sequence. the deduced amin ... | 1992 | 1542317 |
| isolation of cdna clones encoding proteins of complex structures: analysis of the trypanosoma brucei cytoskeleton. | we have adapted a group of well-known procedures in order to devise a simple method that allows the isolation of specific cdnas encoding proteins located in different regions of the trypanosoma brucei cytoskeleton. cdna clones were isolated by screening a lambda gt11 expression library with a polyspecific, polyclonal antiserum against a complex immunogen, in this case the complete cytoskeleton. the fusion proteins produced by the clones were then used as an affinity immunoadsorbant to select mon ... | 1992 | 1544578 |
| a gene from the variant surface glycoprotein expression site encodes one of several transmembrane adenylate cyclases located on the flagellum of trypanosoma brucei. | the bloodstream form of trypanosoma brucei contains transcripts of at least four genes showing partial sequence homology to the genes for eucaryotic adenylate and guanylate cyclases (s. alexandre, p. paindavoine, p. tebabi, a. pays, s. halleux, m. steinert, and e. pays, mol. biochem. parasitol. 43:279-288, 1990). one of these genes, termed esag 4, belongs to the polycistronic transcription unit of the variant surface glycoprotein (vsg) gene. whereas esag 4 is transcribed only in the bloodstream ... | 1992 | 1545803 |
| characterization of different proteolytic activities in trypanosoma brucei brucei. | the variant surface glycoprotein of african trypanosomes is released after overnight incubation of parasites at 4 degrees c in ph 5.5 phosphate glucose buffer and may be purified by concanavalin a sepharose affinity chromatography. the addition of proteinase inhibitors during the parasite incubation is necessary to prevent the proteolysis of the variant surface glycoprotein by the trypanosomal released proteinases. using this procedure without the addition of proteinase inhibitors, the proteolyt ... | 1992 | 1547283 |
| kinetoplastid rna editing: in vitro formation of cytochrome b grna-mrna chimeras from synthetic substrate rnas. | rna editing in the kinetoplastid trypanosoma brucei results in the addition and deletion of uridine residues within several mitochondrial mrnas. the site and number of uridines added appears to be directed by small (approximately 70 nt) guide rnas (grnas), which can base pair to the edited sequences. we examined reactions involving synthetic cytochrome b (cyb) grna and pre-edited mrna in vitro. a major product of the in vitro reaction is a chimeric rna molecule containing both grna and mrna sequ ... | 1992 | 1547505 |
| nucleotide sequence of the gene encoding the largest subunit of the dna-dependent rna polymerase iii of giardia lamblia. | | 1992 | 1549483 |
| cyclic 2',3'-phosphates and nontemplated nucleotides at the 3' end of spliceosomal u6 small nuclear rna's. | spliceosomal u6 small nuclear rna (u6 rna) in species as diverse as man, frog, fruitfly, and soybean have at their 3' ends a cyclic 2',3'-phosphate (greater than p) apparently derived from uridylic acid residues that were added post-transcriptionally. the 3' ends of u6 rna's from various sources may be processed in different ways, or to different extents, depending on the organism or stage of development. the presence of a greater than p terminus on u6 rna may influence the activity of u6 rna ei ... | 1992 | 1549778 |
| calcium homeostasis in procyclic and bloodstream forms of trypanosoma brucei. lack of inositol 1,4,5-trisphosphate-sensitive ca2+ release. | when trypanosoma brucei procyclic trypomastigotes were permeabilized with digitonin in a reaction medium containing mgatp, succinate, and 3.5 microm free ca2+, they lowered the medium ca2+ concentration to the submicromolar level (0.05-0.1 microm), a range that correlates favorably with that detected in the intact cells with fura-2. the carbonyl cyanide p-trifluoromethoxyphenylhydrazone-insensitive ca2+ uptake, certainly represented by the endoplasmic reticulum, was completely inhibited by 500 m ... | 1992 | 1556113 |
| isolation and characterization of a unique 15 kilodalton trypanosome subpellicular microtubule-associated protein. | a protein of 15 kda (p15) was isolated from trypanosoma brucei subpellicular microtubules by tubulin affinity chromatography. the protein bound tubulin specifically both in its native form and after sds-page in tubulin overlay experiments. p15 promoted both the in vitro polymerization of purified calf brain tubulin and the bundling of preformed mammalian microtubules. immunolabeling identified p15 at multiple sites along microtubule polymers comprising calf brain tubulin and p15 as well as on th ... | 1992 | 1559265 |
| the sequence, organization, and expression of the major cysteine protease (cruzain) from trypanosoma cruzi. | the complete sequence of the gene encoding the major cysteine protease from trypanosoma cruzi is reported. the amino acid sequence predicted from the gene sequence aligns well with members of the papain family of cysteine proteases, suggesting the name cruzain. the sequence is most closely related to the cysteine protease of trypanosoma brucei (59.3%) and the murine cathepsin l (42.2%). at least six copies of the gene are present in the genome and are organized in a tandem array of copies which ... | 1992 | 1559982 |
| differential expression of two mrnas from a single gene encoding an hmg1-like dna binding protein of african trypanosomes. | we have isolated cdna clones expressing a member of the high mobility group (hmg) protein family by screening a trypanosoma brucei rhodesiense expression cdna library with multimerized oligonucleotides corresponding to an octamer transcriptional regulatory sequence motif. the trypanosome dna binding protein (tdp-1) encoded by these cdnas contains two domains that show striking sequence similarity to the consensus sequence for hmg1-like dna binding domains (hmg boxes). southern blot analysis is c ... | 1992 | 1565127 |
| sequence analysis of small subunit ribosomal rna genes and its use for detection and identification of leishmania parasites. | the sequence of the most variable part of the small subunit ribosomal rna (ssu rrna) gene, comprising 800 bases, was analysed for 9 leishmania taxa and compared with those of trypanosoma brucei, trypanosoma cruzi and crithidia fasciculata. considerable differences were observed between the sequence of the leishmania taxa on the one hand and those of crithidia and trypanosoma on the other. amongst the leishmania taxa only a few point mutations were found, all located within 2 sequence blocks in t ... | 1992 | 1565128 |
| the 7sl rna homologue of trypanosoma brucei is closely related to mammalian 7sl rna. | in eukaryotes, protein translocation across the endoplasmic reticulum is mediated by a signal recognition particle, a small ribonucleoprotein (rnp) containing 7sl rna. we have cloned and sequenced the gene coding for the trypanosoma brucei 7sl rna homologue and found that its sequence shows the highest degree of similarity to the human 7sl rna sequence. in keeping with the prototype secondary structure of eukaryotic 7sl rna, the trypanosome 7sl rna secondary structure can be folded into four dom ... | 1992 | 1565138 |
| purification of novel calcium binding proteins from trypanosoma brucei: properties of 22-, 24- and 38-kilodalton proteins. | the present study was undertaken to systematically purify calcium binding proteins (cabps) from homogenates of trypanosoma brucei. this work is important since cabps either serve as intracellular calcium buffers or mediate cellular response to calcium signals. disruption of either process should be lethal to trypanosomes. we report that the 45ca-gel overlay assay can be used to detect cabps following fractionation on de-52, phenyl-sepharose, mono-q, and superose 12. specific cabps of 22, 24, and ... | 1992 | 1565142 |
| diagnosis of trypanosoma brucei gambiense sleeping sickness using an antigen detection enzyme-linked immunosorbent assay. | a monoclonal antibody-based enzyme-linked immunosorbent assay (antigen elisa) developed for detection of trypanosome antigens in the serum and cerebrospinal fluid (csf) of patients as a means for diagnosis of trypanosoma brucei gambiense sleeping sickness was evaluated at the bureau central de la trypanosomiase, kinshasa, zaire. sixty-nine (89.6%) of 77 parasitologically confirmed cases examined at the daloa clinic had antigens in serum; 35 (45.5%) had antigens in csf and, in 4 of these, the ant ... | 1992 | 1566302 |
| multicentre evaluation of an antigen-detection elisa for the diagnosis of trypanosoma brucei rhodesiense sleeping sickness. | the performance of an enzyme-linked immunosorbent assay (antigen elisa) for the detection, in serum or cerebrospinal fluid, of an invariant trypanosome antigen to diagnose trypanosoma brucei rhodesiense sleeping sickness was evaluated in four clinical treatment centres. the test, which was carried out in polystyrene test-tubes, was positive in 88 (88.9%) of 99 parasitologically confirmed cases that were tested at the national institute for medical research, tabora, united republic of tanzania; 9 ... | 1992 | 1568281 |
| comparative physiology of two protozoan parasites, leishmania donovani and trypanosoma brucei, grown in chemostats. | cultures of the insect stage of the protozoan parasites leishmania donovani and trypanosoma brucei were grown in chemostats with glucose as the growth rate-limiting substrate. l. donovani has a maximum specific growth rate (mu max) of 1.96 day-1 and a ks for glucose of 0.1 mm; the mu max of t. brucei is 1.06 day-1 and the ks is 0.06 mm. at each steady state (specific growth rate, mu, equals d, the dilution rate), the following parameters were measured: external glucose concentration (glcout), ce ... | 1992 | 1569022 |
| comparison of the refined crystal structures of liganded and unliganded chicken, yeast and trypanosomal triosephosphate isomerase. | the refined crystal structures of chicken, yeast and trypanosomal triosephosphate isomerase (tim) have been compared. tim is known to exist in an "open" (unliganded) and "closed" (liganded) conformation. for chicken tim only the refined open structure is available, whereas for yeast tim and trypanosomal tim refined structures of both the open and the closed structure have been used for this study. comparison of these structures shows that the open structures of chicken tim, yeast tim and trypano ... | 1992 | 1569570 |