| trypanosoma brucei rna editing complex: band ii is structurally critical and maintains band v ligase, which is nonessential. | maturation of trypanosoma brucei mitochondrial mrna involves massive posttranscriptional insertion and deletion of uridine residues. this rna editing utilizes an enzymatic complex with seven major proteins, band i through band vii. we here use rna interference (rnai) to examine the band ii and band v proteins. band ii is found essential for viability; it is needed to maintain the normal structure of the editing complex and to retain the band v ligase protein. previously, band iii was found essen ... | 2003 | 14560033 |
| proventriculus (cardia) plays a crucial role in immunity in tsetse fly (diptera: glossinidiae). | fat body and hemocytes play a central role in cellular and humoral responses for systemic infections in invertebrates, similar to the mammalian liver and blood cells. epithelial surfaces, in particular the midgut, participate in the initial local immune responses in order to aid in the generation of the terminal cytotoxic molecules that mediate non-self recognition. here, we describe for the first time the immune responses of a cluster of cells at the foregut/midgut junction--known as proventric ... | 2003 | 14563366 |
| non-canonical eukaryotic glutaminyl- and glutamyl-trna synthetases form mitochondrial aminoacyl-trna in trypanosoma brucei. | glutaminyl-trna synthetase is thought to be absent from organelles. instead, gln-trna is formed via the transamidation pathway, the other route to this essential compound in protein biosynthesis. however, it was previously shown that glutaminyl-trna synthetase activity is present in leishmania mitochondria. this work identifies genes encoding glutaminyl- and glutamyl-trna synthetase in the closely related organism trypanosoma brucei. down-regulation of their respective gene products by rna inter ... | 2004 | 14563839 |
| the karyote physico-chemical genomic, proteomic, metabolic cell modeling system. | modeling approaches to the dynamics of a living cell are presented that are strongly based on its underlying physical and chemical processes and its hierarchical spatio-temporal organization. through the inclusion of a broad spectrum of processes and a rigorous analysis of the multiple scale nature of cellular dynamics, we are attempting to advance cell modeling and its applications. the presentation focuses on our cell modeling system, which integrates data archiving and quantitative physico-ch ... | 2003 | 14583116 |
| a chromosomal sir2 homologue with both histone nad-dependent adp-ribosyltransferase and deacetylase activities is involved in dna repair in trypanosoma brucei. | sir2-like proteins have been implicated in a wide range of cellular events including chromosome silencing, chromosome segregation, dna recombination and the determination of life span. we report here the molecular and functional characterization of a sir2-related protein from the protozoan parasite trypanosoma brucei, which we termed tbsir2rp1. this protein is a chromosome-associated nad-dependent enzyme which, in contrast to other known proteins of this family, catalyses both adp-ribosylation a ... | 2003 | 14592982 |
| impaired dimerization and trafficking of esag6 lacking a glycosyl-phosphatidylinositol anchor. | | 2003 | 14599669 |
| the mitotic stability of the minichromosomes of trypanosoma brucei. | | 2003 | 14599670 |
| comparative analysis of editosome proteins in trypanosomatids. | detailed comparisons of 16 editosome proteins from trypanosoma brucei, trypanosoma cruzi and leishmania major identified protein motifs associated with catalysis and protein or nucleic acid interactions that suggest their functions in rna editing. five related proteins with rnase iii-like motifs also contain a u1-like zinc finger and either dsrbm or pumilio motifs. these proteins may provide the endoribonuclease function in editing. two other related proteins, at least one of which is associated ... | 2003 | 14602897 |
| screening of plant extracts for antiprotozoal and cytotoxic activities. | methanolic and aqueous extracts derived from 43 plant species, selected either from ethnobotanical or chemotaxonomical data, were screened for their antiprotozoal activity against leishmania donovani and trypanosoma brucei brucei. the cytotoxic activity against kb cells was also determined. eight extracts had ic50 values of less than 10 microg/ml against leishmania donovani. the most active was triclisia patens with an ic50 value of 1.5 microg/ml against leishmania donovani. annona purpurea and ... | 2003 | 14611881 |
| heme oxygenase in candida albicans is regulated by hemoglobin and is necessary for metabolism of exogenous heme and hemoglobin to alpha-biliverdin. | candida albicans is an opportunistic pathogen that has adapted uniquely to life in mammalian hosts. one of the host factors recognized by this yeast is hemoglobin, which binds to a specific cell surface receptor. in addition to its regulating the expression of adhesion receptors on the yeast, we have found that hemoglobin induces the expression of a c. albicans heme oxygenase (cahmx1p). hemoglobin transcriptionally induces the cahmx1 gene independent of the presence of inorganic iron in the medi ... | 2004 | 14615478 |
| a pyrophosphatase regulating polyphosphate metabolism in acidocalcisomes is essential for trypanosoma brucei virulence in mice. | we report the functional characterization of a soluble pyrophosphatase (tbvsp1), which localizes to acidocalcisomes, a vesicular acidic compartment of trypanosoma brucei. depending on the ph and the cofactors mg(2+) or zn(2+), both present in the compartment, the enzyme hydrolyzes either inorganic pyrophosphate (pp(i)) (k(cat) = 385 s(-1)) or tripolyp (polyp(3)) and polyphosphate (polyp) of 28 residues (polyp(28)) with k(cat) values of 52 and 3.5 s(-1), respectively. an unusual n-terminal domain ... | 2004 | 14615483 |
| a comparative study on the clinical, parasitological and molecular diagnosis of bovine trypanosomosis in uganda. | the clinical, parasitological and molecular diagnosis of bovine trypanosomosis were compared using samples from 250 zebu cattle exposed to natural trypanosome challenge in uganda. clinical examination, molecular and parasitological diagnoses detected 184 (73.6%), 96 (38.4%) and 36 (14.4%) as diseased, respectively. the sensitivity and specificity of clinical examination were 87.5% and 35%, and 78 % and 27 % based on molecular and parasitological diagnoses, as gold standards, respectively. of the ... | 2003 | 14621317 |
| crystal structure of trypanosoma cruzi glyceraldehyde-3-phosphate dehydrogenase complexed with an analogue of 1,3-bisphospho-d-glyceric acid. | we report here the first crystal structure of a stable isosteric analogue of 1,3-bisphospho-d-glyceric acid (1,3-bpga) bound to the catalytic domain of trypanosoma cruzi glycosomal glyceraldehyde-3-phosphate dehydrogenase (ggapdh) in which the two phosphoryl moieties interact with arg249. this complex possibly illustrates a step of the catalytic process by which arg249 may induce compression of the product formed, allowing its expulsion from the active site. structural modifications were introdu ... | 2003 | 14622286 |
| structure of thioredoxin from trypanosoma brucei brucei. | the three-dimensional structure of thioredoxin from trypanosoma brucei brucei has been determined at 1.4 a resolution. the overall structure is more similar to that of human thioredoxin than to any other thioredoxin structure. the most striking difference to other thioredoxins is the absence of a buried carboxylate behind the active site cysteines. instead of the common asp, there is a trp that binds an ordered water molecule probably involved in the protonation/deprotonation of the more buried ... | 2003 | 14623083 |
| a role for the exosome in the in vivo degradation of unstable mrnas. | in mammals, the mrnas encoding many proteins involved in inflammation bear destabilizing au-rich elements (ares) in the 3'-untranslated region. the exosome, a complex of 3' --> 5' exonucleases, is rate limiting in the destruction of such mrnas in a mammalian in vitro system, but a role in vivo has not been demonstrated. the phenomenon of are-mediated degradation also occurs in the protist parasite trypanosoma brucei. messenger rnas with 3'-untranslated region u-rich elements, which strongly rese ... | 2003 | 14624005 |
| pcr-rflp using ssu-rdna amplification: applicability for the diagnosis of mixed infections with different trypanosome species in cattle. | the use of a single restriction fragment length polymorphism (rflp)-pcr assay which is able to characterise all important bovine trypanosome species was evaluated for the detection of mixed infections with trypanosoma brucei brucei, trypanosoma theileri, trypanosoma congolense and trypanosoma vivax. results showed that mixed infections are detectable at a minimum ratio of 2%/98% of standardised dna solutions with a concentration of 10 ng ml(-1). all mixed infections gave clear profiles that coul ... | 2003 | 14630427 |
| 5ht1a serotonin receptor agonists inhibit plasmodium falciparum by blocking a membrane channel. | to identify new leads for the treatment of plasmodium falciparum malaria, we screened a panel of serotonin (5-hydroxytryptamine [5ht]) receptor agonists and antagonists and determined their effects on parasite growth. the 5ht1a receptor agonists 8-hydroxy-n-(di-n-propyl)-aminotetralin (8-oh-dpat), 2,5-dimethoxy-4-iodoamphetamine, and 2,5-dimethoxy-4-bromophenylethylamine inhibited the growth of p. falciparum in vitro (50% inhibitory concentrations, 0.4, 0.7, and 1.5 microm, respectively). in fur ... | 2003 | 14638487 |
| a sequence motif within trypanosome precursor trnas influences abundance and mitochondrial localization. | trypanosoma brucei lacks mitochondrial genes encoding trnas and must import nuclearly encoded trnas from the cytosol. the mechanism and specificity of this process remain unclear. we have identified a unique sequence motif, ygg(c/a)rrc, upstream of the genes encoding mitochondrially localized trnas in t. brucei. both in vitro import studies and in vivo transfection studies indicate that deletion of the ygg(c/a)rrc sequence alters mitochondrial localization of trna(leu), and in vivo studies also ... | 2003 | 14645518 |
| selective antimicrotubule activity of n1-phenyl-3,5-dinitro-n4,n4-di-n-propylsulfanilamide (gb-ii-5) against kinetoplastid parasites. | analogs of the antimitotic herbicide oryzalin (3,5-dinitro-n4,n4-di-n-propylsulfanilamide) were recently prepared that were more potent in vitro than the parent compound against the kinetoplastid parasite leishmania donovani (bioorg med chem lett 12:2395-2398, 2002). in the present work, we show that the most active molecule in the group, n1-phenyl-3,5-dinitro-n4,n4-di-n-propylsulfanilamide (gb-ii-5), is a potent, selective antimitotic agent against kinetoplastid parasites. gb-ii-5 possesses ic5 ... | 2003 | 14645662 |
| characterization of components of the mismatch repair machinery in trypanosoma brucei. | mismatch repair is one of a number of dna repair pathways that cells possess to deal with damage to their genome. mismatch repair is concerned with the recognition and correction of incorrectly paired bases, which can be base-base mismatches or insertions or deletions of a few bases, and appears to have been conserved throughout evolution. primarily, this is concerned with increasing the fidelity of dna replication, but also has important roles in the regulation of homologous recombination and t ... | 2004 | 14651619 |
| a metallo phosphatase activity present on the surface of trypanosoma brucei procyclic forms. | in this work, we describe how living cells of trypanosoma brucei procyclic forms were able to hydrolyze extracellular p-nitrophenylphosphate (pnpp). these intact parasites, which had their viability determined by motility and the trypan blue method, presented a low level of pnpp hydrolysis in the absence of any divalent metal (0.72+/-0.07 nmol pnp/mg min). interestingly, in the presence of 5mm mgcl(2), ectophosphatase activity of 1.91+/-0.21 nmol pnp/mg min was observed. the ectophosphatase acti ... | 2003 | 14651871 |
| deletion of the gpideac gene alters the location and fate of glycosylphosphatidylinositol precursors in trypanosoma brucei. | glycosylphosphatidylinositol (gpi) membrane anchors are ubiquitous among the eukaryotes. in most organisms, the pathway of gpi biosynthesis involves inositol acylation and inositol deacylation as discrete steps at the beginning and end of the pathway, respectively. the bloodstream form of the protozoan parasite trypanosoma brucei is unusual in that these reactions occur on multiple gpi intermediates and that it can express side chains of up to six galactose residues on its mature gpi anchors. an ... | 2003 | 14661966 |
| coordination of cell cycle and cytokinesis in trypanosoma brucei. | in common with all eukaryotic cells, trypanosomes must coordinate a complex series of morphogenetic events both temporally and spatially during the cell cycle. the structural and molecular cues that synchronise these events in trypanosomes have started to be elucidated, and intriguingly although similarities to cell cycle events in other eukaryotes can be identified, trypanosomes have also evolved novel solutions to the common challenges faced by dividing eukaryotic cells. although cellular morp ... | 2003 | 14662356 |
| effects of depletion and overexpression of the trypanosoma brucei ribonuclease l inhibitor homologue. | | 2004 | 14668021 |
| functional expression and characterization of a purine nucleobase transporter gene from leishmania major. | leishmania major, like all the other kinetoplastid protozoa, are unable to synthesize purines and rely on purine nucleobase and nucleoside acquisition across the parasite plasma membrane by specific permeases. although, several genes have been cloned that encode nucleoside transporters in leishmania and trypanosoma brucei, much less progress has been made on nucleobase transporters, especially at the molecular level. the studies reported here have cloned and expressed the first gene for a l. maj ... | 2004 | 14668134 |
| tbago1, an argonaute protein required for rna interference, is involved in mitosis and chromosome segregation in trypanosoma brucei. | rna silencing processes are widespread in almost all eukaryotic organisms. they have various functions including genome protection, and the control of gene expression, development and heterochromatin formation. rna interference (rnai) is the post-transcriptional destruction of rna, which is mediated by a ribonucleoprotein complex that contains, among several components, rna helicases and argonaute proteins. rnai is functional in trypanosomes, protozoan parasites that separated very early from th ... | 2003 | 14670085 |
| the single dynamin-like protein of trypanosoma brucei regulates mitochondrial division and is not required for endocytosis. | members of the evolutionarily conserved dynamin-related gtpase family mediate numerous cellular membrane remodeling events. dynamin family functions include the scission of clathrin-coated pits from the plasma membrane, mitochondrial fission, and chloroplast division. here we report that the divergent eukaryote trypanosoma brucei possesses a single dynamin family gene, which we have designated tbdlp. furthermore, a single dynamin family gene is also found in the leishmania major and trypanosoma ... | 2004 | 14670954 |
| argonaute protein in the early divergent eukaryote trypanosoma brucei: control of small interfering rna accumulation and retroposon transcript abundance. | members of the argonaute protein family have been linked through a combination of genetic and biochemical studies to rna interference (rnai) and related phenomena. here, we describe the characterization of the first argonaute protein (ago1) in trypanosoma brucei, the earliest divergent eukaryote where rnai has been described so far. ago1 is predominantly cytoplasmic and is found in a ribonucleoprotein particle with small interfering rnas (sirnas), and this particle is present in a soluble form, ... | 2004 | 14673174 |
| the effect of rna interference down-regulation of rna editing 3'-terminal uridylyl transferase (tutase) 1 on mitochondrial de novo protein synthesis and stability of respiratory complexes in trypanosoma brucei. | inhibition of rna editing by down-regulation of expression of the mitochondrial rna editing tutase 1 by rna interference had profound effects on kinetoplast biogenesis in trypanosoma brucei procyclic cells. de novo synthesis of the apocytochrome b and cytochrome oxidase subunit i proteins was no longer detectable after 3 days of rnai. the effect on protein synthesis correlated with a decline in the levels of the assembled mitochondrial respiratory complexes iii and iv, and also cyanide-sensitive ... | 2004 | 14681226 |
| clinical follow-up in the rat experimental model of african trypanosomiasis. | animal models of human african trypanosomiasis (hat) have been developed to understand the pathogenic mechanisms leading to the passage into the neurological phase, most of them referring to histological aspects but not clinical or behavioral data. our study aimed at defining simple clinical and/or behavioral markers of the passage between the hemolymphatic phase and the meningo-encephalitic stage of the disease. sprague-dawley rats (n=24) were infected with trypanosoma brucei brucei antat 1.1e. ... | 2003 | 14681551 |
| activities of pt(ii) and ru(iii) triazole-pyrimidine complexes against trypanosoma cruzi and t. brucei brucei. | we studied the biological activity of three newly synthesized metal complexes of triazole-pyrimidine derivatives that were previously observed to inhibit in vitro growth of epimastigotes of trypanosoma cruzi and procyclic forms of trypanosoma brucei brucei. we analyzed the possible inhibitory effect of these compounds on the synthesis of dna, rna and protein, ultrastructure and excretion of metabolites by these parasites. rna synthesis was inhibited by all three complexes assayed. these complexe ... | 2004 | 14685011 |
| the ingi and rime non-ltr retrotransposons are not randomly distributed in the genome of trypanosoma brucei. | the ingi (long and autonomous) and rime (short and nonautonomous) non--long-terminal repeat retrotransposons are the most abundant mobile elements characterized to date in the genome of the african trypanosome trypanosoma brucei. these retrotransposons were thought to be randomly distributed, but a detailed and comprehensive analysis of their genomic distribution had not been performed until now. to address this question, we analyzed the ingi/rime sequences and flanking sequences from the ongoin ... | 2004 | 14694076 |
| the 6-phosphogluconate dehydrogenase from trypanosoma cruzi: the absence of two inter-subunit salt bridges as a reason for enzyme instability. | the third enzyme of the pentose phosphate pathway (ppp), 6-phosphogluconate dehydrogenase (6pgdh), is present in the four major stages of trypanosoma cruzi, cl brener clone. the enzyme was too unstable to be purified from epimastigote cell-free extracts. two genes encoding 6pgdh were cloned and sequenced; the predicted amino acid sequences differ only in five non-essential residues. since southern blots suggested the presence of a single copy per haploid genome, the two genes found are probably ... | 2004 | 14698432 |
| trypanosome apoptotic factor mediates apoptosis in human brain vascular endothelial cells. | human african trypanosomiasis (hat, sleeping sickness) is a devastating disease caused by infection with trypanosoma brucei ssp. these hemoflagellates invade the central nervous system (cns) and induce meningo-encephalitis, neuronal demyelination, blood-brain-barrier (bbb) dysfunction, peri-vascular infiltration, astrocytosis and apoptosis. the molecular basis of these manifestations is unclear. we previously reported t. brucei-induced apoptosis in cerebella and brain-stem nuclei in mice at peak ... | 2004 | 14698435 |
| base j, found in nuclear dna of trypanosoma brucei, is not a target for dna glycosylases. | base excision repair (ber) is an evolutionarily conserved system which removes altered bases from dna. the initial step in ber is carried out by dna glycosylases which recognize altered bases and cut the n-glycosylic bond between the base and the dna backbone. in kinetoplastid flagellates, such as trypanosoma brucei, the modified base beta-d-glucosyl-hydroxymethyluracil (j) replaces a small percentage of thymine residues, predominantly in repetitive telomeric sequences. base j is synthesized at ... | 2004 | 14706348 |
| design and synthesis of peptidomimetic protein farnesyltransferase inhibitors as anti-trypanosoma brucei agents. | on the basis of the structure of the cvim tetrapeptide substrate of mammalian protein farnesyltransferase, a series of imidazole-containing peptidomimetics was designed and synthesized, and their inhibition activity against trypanosoma brucei protein farnesyltransferase (tbpft) was evaluated. peptidomimetics where the 5-position of the imidazole ring was linked to the hydrophobic scaffold showed over 70% inhibition activity at 50 nm in the enzyme assay, whereas the corresponding c-4 regioisomers ... | 2004 | 14711313 |
| trypanosoma brucei plasma membrane-type ca(2+)-atpase 1 (tbpmc1) and 2 (tbpmc2) genes encode functional ca(2+)-atpases localized to the acidocalcisomes and plasma membrane, and essential for ca(2+) homeostasis and growth. | trypanosoma brucei adaptation and survival in its host involve integrated regulation of ca(2+) pumps (ca(2+)-atpases), which are essential in calcium ion homeostasis. here we report the cloning and sequencing of two genes (tbpmc1 and tbpmc2) encoding plasma membrane-type ca(2+)-atpases (pmcas) of t. brucei, an agent of african trypanosomiasis. indirect immunofluorescence analysis using antibodies against the proteins and against epitope tags introduced into each protein showed that tbpmc1 co-loc ... | 2004 | 14724285 |
| bloodstream form-specific up-regulation of silent vsg expression sites and procyclin in trypanosoma brucei after inhibition of dna synthesis or dna damage. | the african trypanosome trypanosoma brucei transcribes the active variant surface glycoprotein (vsg) gene from one of about 20 vsg expression sites (ess). in order to study es control, we made reporter lines with a green fluorescent protein gene inserted behind the promoter of different ess. we attempted to disrupt the silencing machinery, and we used fluorescence-activated cell sorter analysis for the rapid and sensitive detection of es up-regulation. we find that a range of treatments that eit ... | 2004 | 14726511 |
| molecular profiles of trypanosoma brucei, t. evansi and t. equiperdum stocks revealed by the random amplified polymorphic dna method. | a total of 20 random primers (10-mers) were used to amplify rapd markers from the genomic dna of four trypanosoma brucei stocks from east and west africa, four t. evansi stocks from africa, asia and south america and one t. equiperdum stock from asia. between 65 and 88 reproducible fragments ranging from 0.25 to 2.15 kb were generated from these stocks depending on the stock/primer combination. the similarity coefficient (sc) among the stocks of t. brucei from kenya, nigeria, tanzania and zambia ... | 2004 | 14727188 |
| megazol combined with suramin improves a new diagnosis index of the early meningo-encephalitic phase of experimental african trypanosomiasis. | in human african trypanosomiasis (hat), the parasites invade the central nervous system (cns), leading to the development of meningo-encephalitis and an irreversible demyelinating process, which kills the patient unless specific treatment is undertaken. among the experimental trypanocides, the nitroimidazole derivative megazol alone at optimal doses does not cure late-stage disease tested in mouse models, however the combination of suramin and megazol is able to cure infected mice without cns in ... | 2004 | 14728611 |
| tbpde1, a novel class i phosphodiesterase of trypanosoma brucei. | cyclic nucleotide specific phosphodiesterases (pdes) are important components of all camp signalling networks. in humans, 11 different pde families have been identified to date, all of which belong to the class i pdes. pharmacologically, they have become of great interest as targets for the development of drugs for a large variety of clinical conditions. pdes in parasitic protozoa have not yet been extensively investigated, despite their potential as antiparasitic drug targets. the current study ... | 2004 | 14728691 |
| successful design and synthesis of a polarity-triggered beta-->alpha conformational switch using the side chain interaction index (scii) as a measure of local structural stability. | certain sequences within proteins have the ability to undergo an abrupt cooperative conformational switch from beta-strand to helix in response to decreasing polarity of the environment. this behavior was first observed at the cd4 binding site of the envelope glycoprotein gp120 of hiv-1, but evidence has accumulated that polarity-driven beta --> alpha switches may be widespread, serving both to facilitate binding on protein/membrane or protein/protein contact and to signal that docking has occur ... | 2004 | 14730964 |
| cationic antimicrobial peptide killing of african trypanosomes and sodalis glossinidius, a bacterial symbiont of the insect vector of sleeping sickness. | nine biochemically distinct cationic antimicrobial peptides were tested in vitro for their effects on bloodstream forms and procyclic (insect) forms of african trypanosomes, the protozoan parasites that cause african sleeping sickness in humans and trypanosomiasis in domestic animals. at low concentrations, one peptide completely inhibited growth of bloodstream forms, one inhibited procyclic forms, and five inhibited both trypanosome life cycle stages. the peptides were also tested on sodalis gl ... | 2003 | 14733670 |
| p75 tumor necrosis factor-receptor shedding occurs as a protective host response during african trypanosomiasis. | in experimental murine trypanosomiasis, resistance is often scored as the capacity to control peak parasitemia levels, which results in prolonged survival. infection-induced pathology has not systematically been used as a resistance criterion. because this parameter could be the most relevant for comparative analysis of natural and experimental infections, as well as for understanding of pathology-associated immune alterations, we analyzed trypanosoma brucei infections in 4 different established ... | 2004 | 14745712 |
| the transmission of mixed trypanosoma brucei brucei/t. congolense infections by tsetse (glossina morsitans morsitans). | laboratory experiments and field observations clearly show that tsetse flies can be carriers of mixed trypanosome infections. question remains how easy it is for the tsetse fly to acquire such a mixed infection during the first bloodmeal. this is of particular importance in the epidemiology of trypanosoma brucei s.l., often a cryptic infection and difficult to transmit to non-teneral tsetse flies. to determine the transmission rate of t. brucei as part of a mixed infection, teneral glossina mors ... | 2004 | 14746974 |
| enhanced survival of rats concurrently infected with trypanosoma brucei and strongyloides ratti. | the interaction between the blood protozoan parasite, trypanosoma brucei and the gastrointestinal nematode parasite, strongyloides ratti was studied in outbred white albino rats. rats were grouped and given either single infection with t. brucei or s. ratti or concurrently infected with both parasites. blood parasitaemia and packed cell volume, faecal egg/larva output, adult worm burden and survivability were monitored in order to assess the interactive effects of the infections. all trypanosome ... | 2004 | 14746976 |
| integration of pzjm library plasmids into unexpected locations in the trypanosoma brucei genome. | | 2004 | 14747155 |
| mast cells, histamine and the pathogenesis of intestinal damage in experimental trypanosoma brucei brucei infections. | intestinal damage with increased permeability is a prominent feature of experimental african trypanosomiasis. the possible involvement of mast cells and histamine in the altered gut integrity was investigated, at the level of the jejunum, in balb/c mice infected with trypanosoma brucei brucei. mast cells were studied by selective staining of granule content with alcian blue/safranin and quantitative histology, and histamine concentrations were determined by a fluorimetric method. mast-cell activ ... | 2003 | 14754492 |
| the trypanosoma brucei spliced leader rna and rrna gene promoters have interchangeable tbsnap50-binding elements. | in the protist parasite trypanosoma brucei, the small nuclear spliced leader (sl) rna and the large rrnas are key molecules for mrna maturation and protein synthesis, respectively. the sl rna gene (slrna) promoter recruits rna polymerase ii and consists of a bipartite upstream sequence element (use) and an element close to the transcription initiation site. here, we analyzed the distal part of the ribosomal (rrna) promoter and identified two sequence blocks which, in reverse orientation, closely ... | 2004 | 14757834 |
| splenic denervation suppresses mrna gene expression and protein production of il-1beta and il-6 by peritoneal macrophages in both trypanosoma brucei brucei-infected and non-infected rats. | to test the hypothesis that the nervous system participates in modulating the immune response during experimental african trypanosomiasis caused by trypanosoma brucei brucei. | 2004 | 14758057 |
| transformation of monomorphic and pleomorphic trypanosoma brucei. | african trypanosomes, such as trypanosoma brucei, are protozoan parasites of mammals that were first described over 100 hundred years ago. they have long been the subjects of biological investigation, which has yielded insights into a number of fundamental, as well as novel, cellular processes in all organisms. in the last decade or so, genetic manipulation of trypanosomes has become possible through dna transformation, allowing yet more detailed analysis of the biology of the parasite. one face ... | 2004 | 14769956 |
| smd1 is required for spliced leader rna biogenesis. | the sm-binding site of the kinetoplastid spliced leader rna has been implicated in accurate spliced leader rna maturation and trans-splicing competence. in trypanosoma brucei, rna interference-mediated knockdown of smd1 caused defects in spliced leader rna maturation, displaying aberrant 3'-end formation, partial formation of cap 4, and overaccumulation in the cytoplasm; u28 pseudouridylation was unaffected. | 2004 | 14871954 |
| a differential role for actin during the life cycle of trypanosoma brucei. | actin is expressed at similar levels but in different locations in bloodstream and procyclic forms of trypanosoma brucei. in bloodstream forms actin colocalizes with the highly polarized endocytic pathway, whereas in procyclic forms it is distributed throughout the cell. rna interference demonstrated that in bloodstream forms, actin is an essential protein. depletion of actin resulted in a rapid arrest of cell division, termination of vesicular traffic from the flagellar pocket membrane leading ... | 2004 | 14963487 |
| human african trypanosomiasis of the cns: current issues and challenges. | human african trypanosomiasis (hat), also known as sleeping sickness, is a major cause of mortality and morbidity in sub-saharan africa. current therapy with melarsoprol for cns hat has unacceptable side-effects with an overall mortality of 5%. this review discusses the issues of diagnosis and staging of cns disease, its neuropathogenesis, and the possibility of new therapies for treating late-stage disease. | 2004 | 14966556 |
| temporal dissection of bax-induced events leading to fission of the single mitochondrion in trypanosoma brucei. | the protozoan trypanosoma brucei has a single mitochondrion and lacks an apoptotic machinery. here we show that expression of the proapoptotic protein bax in t. brucei causes the release of cytochrome c, the depolarization of the mitochondrial membrane potential and mitochondrial fission. however, in contrast to mammalian cells, the three events are temporally well separated. the release of cytochrome c from the intermembrane space precedes mitochondrial fission, showing that it does not depend ... | 2004 | 14968134 |
| trypanosoma brucei: functions of rbp16 cold shock and rgg domains in macromolecular interactions. | the rna binding protein rbp16 regulates mitochondrial rna editing and stability in trypanosoma brucei. to aid in understanding the biochemical mechanisms of rbp16 function, we analyzed the rna and protein binding capacity of rbp16 and its individual cold shock (csd) and rgg domains. both recombinantly expressed domains possess rna binding activity. however, the specificity and affinity of rbp16 for grna is mediated predominantly through the interaction of the csd with poly(u). the rgg domain con ... | 2003 | 14969691 |
| occurrence, clinical manifestation and the epidemiological implications of naturally occurring canine trypanosomosis in western kenya. | domestic dogs were screened for trypanosoma brucei infection using the haematocrit centrifugation technique as part of routine active surveillance exercises in the busia and teso districts of kenya. the purpose was to assess the role of dogs as sentinels for the occurrence of human sleeping sickness. out of 200 dogs screened, five were found to be infected at the various test sites. these five succumbed to the disease within four weeks, and exhibited a distinct and pronounced corneal opacity bef ... | 2003 | 14971734 |
| glyoxalase ii of african trypanosomes is trypanothione-dependent. | the glyoxalase system is a ubiquitous pathway catalyzing the glutathione-dependent detoxication of ketoaldehydes such as methylglyoxal, which is mainly formed as a by-product of glycolysis. the gene encoding a glyoxalase ii has been cloned from trypanosoma brucei, the causative agent of african sleeping sickness. the deduced protein sequence contains the highly conserved metal binding motif thxhxdh but lacks three basic residues shown to fix the glutathione-thioester substrate in the crystal str ... | 2004 | 14976196 |
| structure of the la motif: a winged helix domain mediates rna binding via a conserved aromatic patch. | the la protein is a ubiquitous nuclear phosphoprotein that recognizes the 3' uridylates found in all newly synthesized rna polymerase iii transcripts. la binding stabilizes these transcripts from exonucleases and may also assist their folding. here we present the first structural insights into how the la protein specifically interacts with its rna substrates. the most conserved region of the la protein is the la motif, a domain also found in several other rna-binding proteins. we have determined ... | 2004 | 14976553 |
| scanning electron microscopy of cells and tissues under fully hydrated conditions. | a capability for scanning electron microscopy of wet biological specimens is presented. a membrane that is transparent to electrons protects the fully hydrated sample from the vacuum. the result is a hybrid technique combining the ease of use and ability to see into cells of optical microscopy with the higher resolution of electron microscopy. the resolution of low-contrast materials is approximately 100 nm, whereas in high-contrast materials the resolution can reach 10 nm. standard immunogold t ... | 2004 | 14988502 |
| circulating antibodies directed against nitrosylated antigens in trypanosome-infected mice. | nitric oxide has been implicated as an effector cytotoxic molecule in trypanosomiasis. in this work, we investigated the presence of circulating antibodies directed against nitrosylated epitopes as biological indicators for nitric oxide (no) production in the sera of trypanosome-infected mice. we tested these sera with synthetic antigens, such as s-nitrosated protein or nitrosylated conjugates of amino acids that possess a high affinity to no, by an immunoenzymatic assay. we detected antibodies ... | 2003 | 14990318 |
| identification and functional characterization of lsm proteins in trypanosoma brucei. | rna interference of sm proteins in trypanosoma brucei demonstrated that the stability of the small nuclear rnas (u1, u2, u4, u5) and the spliced leader rna, but not u6 rna, were affected upon sm depletion (mandelboim, m., barth, s., biton, m., liang, x. h., and michaeli, s. (2003) j. biol. chem. 278, 51469-51478), suggesting that lsm proteins that bind and stabilize u6 rna in other eukaryotes should exist in trypanosomes. in this study, we identified seven lsm proteins (lsm2p to lsm8p) and exami ... | 2004 | 14990572 |
| kinetics of endocytosis and recycling of the gpi-anchored variant surface glycoprotein in trypanosoma brucei. | the dense coat of glycosylphosphatidylinositol (gpi)-anchored variant surface glycoprotein (vsg) covering parasitic african trypanosomes is essential for survival in mammalian hosts. vsg is internalised and recycled exclusively via a specialised part of the plasma membrane, the flagellar pocket. direct measurement of the kinetics of vsg endocytosis and recycling shows that the vsg cell-surface pool is turned over within 12 minutes. correspondingly, the turnover of the intracellular pool (9+/-4% ... | 2004 | 14996937 |
| protein conformer selection by sequence-dependent packing contacts in crystals of 3-phosphoglycerate kinase. | in several crystal structures of 3-phosphoglycerate kinase (pgk), the two domains occupy different relative positions. it is intriguing that the two extreme (open and closed) conformations have never been observed for the enzyme from the same species. furthermore, in certain cases, these different crystalline conformations represent the enzyme-ligand complex of the same composition, such as the ternary complex containing either the substrate 3-phosphoglycerate (3-pg) and beta,gamma-imido-adenosi ... | 2004 | 14997553 |
| twenty-four-hour disruption of the sleep-wake cycle and sleep-onset rem-like episodes in a rat model of african trypanosomiasis. | patients with human african trypanosomiasis (sleeping sickness) due to the inoculation of trypanosoma brucei gambiense or rhodesiense show a major disruption of the 24-hour sleep-wake distribution, accompanied by the occurrence of sleep-onset rapid-eye-movement (rem) sleep episodes, proportional to the severity of the illness. although animal models of human african trypanosomiasis have been developed to understand the pathogenic mechanisms leading to immune alterations, the development of an an ... | 2004 | 14998236 |
| mathematical and statistical analysis of the trypanosoma brucei slender to stumpy transition. | we propose a new model for the stumpy induction factor-induced slender to stumpy transformation of trypanosoma brucei gambiense cells in immunosuppressed mice. the model is a set of delay differential equations that describe the time-course of the infection. we fit the model, using a maximum-likelihood method, to previously published data on parasitaemia in four mice. the model is shown to be a good fit and parameter estimates and confidence intervals are derived. our estimated parameter values ... | 2004 | 15002904 |
| gene synteny and evolution of genome architecture in trypanosomatids. | the trypanosomatid protozoa trypanosoma brucei, trypanosoma cruzi and leishmania major are related human pathogens that cause markedly distinct diseases. using information from genome sequencing projects currently underway, we have compared the sequences of large chromosomal fragments from each species. despite high levels of divergence at the sequence level, these three species exhibit a striking conservation of gene order, suggesting that selection has maintained gene order among the trypanoso ... | 2004 | 15003838 |
| [the flagellum: from cell motility to morphogenesis]. | flagella and cilia are elaborate cytoskeletal structures conserved from protists to mammals, where they fulfil functions related to motility or sensitivity. we demonstrate a novel role for the flagellum in the control of cell morphogenesis and division of trypanosoma brucei. to investigate flagellum functions, its formation was perturbed by inducible rna interference silencing of components required for intraflagellar transport (ift), a dynamic process necessary for flagellum assembly. first, we ... | 2003 | 15005520 |
| trypanosoma brucei oleate desaturase may use a cytochrome b5-like domain in another desaturase as an electron donor. | an open reading frame with fatty acid desaturase similarity was identified in the genome of trypanosoma brucei. the 1224 bp sequence specifies a protein of 408 amino acids with 59% and 58% similarity to mortierella alpina and arabidopsis thaliana delta12 desaturase, respectively, and 51% with a. thaliana omega3 desaturases. the histidine tracks that compose the iron-binding active centers of the enzyme were more similar to those of the omega3 desaturases. expression of the trypanosome gene in sa ... | 2004 | 15009186 |
| comparison of the infection rate of tsetse, glossina morsitans morsitans, fed in vitro or in vivo. | studies were made of infection rates of trypanosomes in the tsetse fly glossina morsitans morsitans westwood (diptera: glossinidae) when maintained in vivo (rabbits) or in vitro on high quality, gamma-irradiated, sterile defibrinated bovine blood, obtained from the entomology unit of the international atomic energy agency (iaea). for both trypanosoma congolense broden and t. b. brucei plimmer & bradford, in vitro maintenance significantly reduced the proportion of flies that developed mature met ... | 2004 | 15009448 |
| loss of the mono-allelic control of the vsg expression sites during the development of trypanosoma brucei in the bloodstream. | transcription of the variant surface glycoprotein (vsg) gene of trypanosoma brucei occurs in a single of multiple polycistronic expression sites (ess). analysis of rna from proliferative long slender (ls) bloodstream forms demonstrated that initiation of transcription occurs in different ess, but inefficient rna processing and elongation is linked to rna polymerase arrest in all except one unit at a time. the pattern of es transcripts was analysed during the transformation of dividing ls forms i ... | 2004 | 15009886 |
| the involvement of two cdc2-related kinases (crks) in trypanosoma brucei cell cycle regulation and the distinctive stage-specific phenotypes caused by crk3 depletion. | cyclin-dependent protein kinases are among the key regulators of eukaryotic cell cycle progression. potential functions of the five cdc2-related kinases (crk) in trypanosoma brucei were analyzed using the rna interference (rna(i)) technique. in both the procyclic and bloodstream forms of t. brucei, crk1 is apparently involved in controlling the g(1)/s transition, whereas crk3 plays an important role in catalyzing cells across the g(2)/m junction. a knockdown of crk1 caused accumulation of cells ... | 2004 | 15010459 |
| trypanosoma brucei: a first-generation cre-loxp site-specific recombination system. | the bacteriophage cre-loxp system of dna recombination is widely used to manipulate segments of the genomes of mice and other eukaryotes for the purpose of studying the regulation and functions of their genes. since this recombination system could have similar applications in analyzing the genomes of trypanosomatids, we assessed the action of cre recombinase on its loxp dna recognition sites in trypanosoma brucei after inserting tetracycline-regulated cre and two 34-bp loxp sites into the t. bru ... | 2004 | 15013787 |
| synthesis and antitubulin activity of n1- and n4-substituted 3,5-dinitro sulfanilamides against african trypanosomes and leishmania. | thirty analogues of n(1)-phenyl-3,5-dinitro-n(4),n(4)-di-n-propylsulfanilamide (gb-ii-5, compound 3), a new antikinetoplastid antimitotic agent, have been synthesized and evaluated. the addition of simple functional groups to the n1 aromatic ring generally decreases antiparasitic and antimitotic potency, but placement of a dibutyl substituent at the n4 nitrogen to give n(1)-phenyl-3,5-dinitro-n(4),n(4)-di-n-butylsulfanilamide (compound 35) augments antitrypanosomal and antileishmanial activity. ... | 2004 | 15027874 |
| antigenic variation in african trypanosomes: monitoring progress. | antigenic variation is central to the success of african trypanosomes and other eukaryotic, bacterial and viral pathogens. our understanding of the control and execution of this immune evasion strategy in trypanosomes is incomplete, despite the molecular basis of antigenic variation being first described over 20 years ago. recent research progress in this field is highlighted here and some of the unresolved questions raised. | 2004 | 15036032 |
| in vitro antitrypanosomal activity of ethnopharmacologically selected beninese plants. | the in vitro antitrypanosomal activity of methylene chloride, methanol and aqueous extracts of the leaves and twigs of five plant species traditionally used in benin for the treatment of sleeping sickness were evaluated on trypanosoma brucei brucei and their selectivity was analysed on leishmania mexicana mexicana and j774 macrophage-like murine cells. the results showed that the four most active extracts had mic values < or =19 microg/ml (hymenocardia acida twig and leaf, strychnos spinosa leaf ... | 2004 | 15036465 |
| interaction of substituted hexose analogues with the trypanosoma brucei hexose transporter. | glucose metabolism is essential for survival of bloodstream form trypanosoma brucei subspecies which cause human african trypanosomiasis (sleeping sickness). hexose analogues may represent good compounds to inhibit glucose metabolism in these cells. delivery of such compounds to the parasite is a major consideration in drug development. a series of d-glucose and d-fructose analogues were developed to explore the limits of the structure-activity relationship of the tht1 hexose transporter of bloo ... | 2004 | 15037198 |
| isolation and characterization of gangliosides from trypanosoma brucei. | gangliosides were isolated from trypanosoma brucei and analyzed by thin-layer chromatography (tlc) and tlc immunostaining test. four species of gangliosides, designated as g-1, g-2, g-3, and g-4, were separated by tlc. g-1 ganglioside had the same tlc migration rate as gm3. in contrast, g-2, g-3, and g-4 gangliosides migrated a little slower than gm1, gd1a, and gd1b, respectively. to characterize the molecular species of gangliosides from t. brucei, g-1, g-2, g-3, and g-4 gangliosides were purif ... | 2004 | 15040678 |
| the t-stem determines the cytosolic or mitochondrial localization of trypanosomal trnasmet. | the mitochondrion of trypanosoma brucei lacks trna genes. organellar translation therefore depends on import of cytosolic, nucleus-encoded trnas. except for the cytosol-specific initiator trna(met), all trypanosomal trnas function in both the cytosol and the mitochondrion. the initiator trna(met) is closely related to the imported elongator trna(met). thus, the distinct localization of the two trnas(met) must be specified by the 26 nucleotides, which differ between the two molecules. using trans ... | 2004 | 15064351 |
| closing the gaps in kinetoplast dna network replication. | | 2004 | 15070715 |
| the flagella connector of trypanosoma brucei: an unusual mobile transmembrane junction. | throughout its elongation, the new flagellum of the procyclic form of the african trypanosome trypanosoma brucei is tethered at its tip to the lateral aspect of the old flagellum. this phenomenon provides a cytotactic mechanism for influencing inheritance of cellular pattern. here, we show that this tethering is produced via a discrete, mobile transmembrane junction - the flagella connector. light and electron microscopy reveal that the flagella connector links the extending microtubules at the ... | 2004 | 15075226 |
| defects in the n-linked oligosaccharide biosynthetic pathway in a trypanosoma brucei glycosylation mutant. | concanavalin a (cona) kills the procyclic (insect) form of trypanosoma brucei by binding to its major surface glycoprotein, procyclin. we previously isolated a mutant cell line, cona 1-1, that is less agglutinated and more resistant to cona killing than are wild-type (wt) cells. subsequently we found that the cona resistance phenotype in this mutant is due to the fact that the procyclin either has no n-glycan or has an n-glycan with an altered structure. here we demonstrate that the alteration i ... | 2004 | 15075256 |
| analysis of gene function in trypanosoma brucei using rna interference. | trypanosoma brucei, a flagellate protozoa of the family trypanosomatidae, has become one of the model systems for unicellular pathogens to study fundamentally important biological phenomena. currently, the method of choice to examine gene function in these organisms is rna interference (rnai). mrna degradation is triggered by double-stranded rna (dsrna) produced in vivo from transgenes transcribed from opposing tetracycline (tet)-inducible t7 rna polymerase promoters, or hairpin rna transcribed ... | 2004 | 15103069 |
| identification and characterization of trypanosome rna-editing complex components. | this chapter describes the methods used to purify the rna-editing complex, to identify the proteins by mass spectrometry, and to demonstrate the functions for some of the proteins. | 2004 | 15103079 |
| rna interference in protozoan parasites. | rna interference or rnai is defined as the mechanism through which gene-specific, double-stranded rna (dsrna) triggers degradation of homologous transcripts. besides providing an invaluable tool to downregulate gene expression in a variety of organisms, it is now evident that rnai extends its tentacles into both the nucleus and the cytoplasm and is involved in a variety of gene silencing phenomena. here we review the current status of rnai in protozoan parasites that cause diseases of considerab ... | 2004 | 15104593 |
| the trypanocide diminazene aceturate is accumulated predominantly through the tbat1 purine transporter: additional insights on diamidine resistance in african trypanosomes. | resistance to diminazene aceturate (berenil) is a severe problem in the control of african trypanosomiasis in domestic animals. it has been speculated that resistance may be the result of reduced diminazene uptake by the parasite. we describe here the mechanisms by which [(3)h]diminazene is transported by trypanosoma brucei brucei bloodstream forms. diminazene was rapidly accumulated through a single transporter, with a k(m) of 0.45 +/- 0.11 micro m, which was dose dependently inhibited by penta ... | 2004 | 15105099 |
| trypanocidal activity of melamine-based nitroheterocycles. | a series of nitroheterocyclic compounds were designed with linkages to melamine or benzamidine groups that are known substrates of the p2 aminopurine and other transporters in african trypanosomes of the brucei group. several compounds showed in vitro trypanotoxicity with 50% inhibitory concentrations in the submicromolar range. although most compounds interacted with the p2 transporter, as judged by their ability to inhibit adenosine transport via this carrier, uptake through this route was not ... | 2004 | 15105128 |
| validation of trypanosoma brucei trypanothione synthetase as drug target. | in trypanosomes, the parasite-specific thiol trypanothione [t(sh)2] fulfills various functions, the best established being detoxification of h2o2 and organic hydroperoxides and ribonucleotide reduction. recently, a trypanothione synthetase (tb-trys) gene from trypanosoma brucei was isolated and the heterologously expressed tb-trys catalyzed the entire synthesis of t(sh)2 from glutathione (gsh) and spermidine in vitro. to confirm the in situ function of the complex tb-trys activities and to evalu ... | 2004 | 15110394 |
| recirculation of trypanosoma brucei brucei in cattle after t. congolense challenge by tsetse flies. | the effect of challenging cattle, chronically infected with trypanosoma brucei brucei, with t. congolense on the development of the t. b. brucei infection was investigated. for this purpose, nine experimental animals were first infected with t. b. brucei through the bites of infected tsetse flies. once the t. b. brucei had developed into a chronic infection, that was difficult to detect using routine parasitological diagnostic tools, seven of the experimental animals were challenged by tsetse fl ... | 2004 | 15110405 |
| transposon mutagenesis of trypanosoma brucei identifies glycosylation mutants resistant to concanavalin a. | we have engineered trypanosoma brucei with a novel mariner transposition system that allows large populations of mutant cells to be generated and screened. as a proof of principle, we isolated and characterized two independent clones that were resistant to the cytotoxic action of concanavalin a. in both clones, the transposon had integrated into the locus encoding a homologue of human alg12, which encodes a dolichyl-p-man: man(7)glcnac(2)-pp-dolichyl-alpha6-mannosyltransferase. conventional knoc ... | 2004 | 15123607 |
| alkaloids from cassytha filiformis and related aporphines: antitrypanosomal activity, cytotoxicity, and interaction with dna and topoisomerases. | cassytha filiformis (lauraceae), a widely distributed parasitic plant, contains several aporphine alkaloids and is often used in african folk medicine to treat cancer, african trypanosomiasis and other diseases. in a previous investigation, we showed that the alkaloid plant extract and the isolated aporphines possessed in vitro cytotoxic properties. in this paper, we evaluated the in vitro activity of the alkaloid extract (ic50 = 2.2 microg/ml) and its three major aporphine alkaloids (actinodaph ... | 2004 | 15124084 |
| mouse strain susceptibility to trypanosome infection: an arginase-dependent effect. | we previously reported that macrophage arginase inhibits no-dependent trypanosome killing in vitro and in vivo. balb/c and c57bl/6 mice are known to be susceptible and resistant to trypanosome infection, respectively. hence, we assessed the expression and the role of inducible no synthase (inos) and arginase in these two mouse strains infected with trypanosoma brucei brucei. arginase i and arginase ii mrna expression was higher in macrophages from infected balb/c compared with those from c57bl/6 ... | 2004 | 15128819 |
| plasma kinetics and efficacy of oral megazol treatment in trypanosoma brucei brucei-infected sheep. | experimentally infected sheep have been previously developed as an animal model of trypanosomosis. we used this model to test the efficacy of megazol on eleven trypanosoma brucei brucei-infected sheep. when parasites were found in blood on day 11 post-infection, megazol was orally administered at a single dose of 40 or 80mg/kg. after a transient aparasitaemic period, all animals except two relapsed starting at day 2 post-treatment, which were considerated as cured on day 150 post-treatment and s ... | 2004 | 15135860 |
| surface sialic acids taken from the host allow trypanosome survival in tsetse fly vectors. | the african trypanosome trypanosoma brucei, which causes sleeping sickness in humans and nagana disease in livestock, is spread via blood-sucking tsetse flies. in the fly's intestine, the trypanosomes survive digestive and trypanocidal environments, proliferate, and translocate into the salivary gland, where they become infectious to the next mammalian host. here, we show that for successful survival in tsetse flies, the trypanosomes use trans-sialidase to transfer sialic acids that they cannot ... | 2004 | 15136592 |
| golgi duplication in trypanosoma brucei. | duplication of the single golgi apparatus in the protozoan parasite trypanosoma brucei has been followed by tagging a putative golgi enzyme and a matrix protein with variants of gfp. video microscopy shows that the new golgi appears de novo, near to the old golgi, about two hours into the cell cycle and grows over a two-hour period until it is the same size as the old golgi. duplication of the endoplasmic reticulum (er) export site follows exactly the same time course. photobleaching experiments ... | 2004 | 15138289 |
| antikinetoplastid activity of 3-aryl-5-thiocyanatomethyl-1,2,4-oxadiazoles. | a series of 5-thiocyanatomethyl- and 5-alkyl-3-aryl-1,2,4-oxadiazoles were synthesized and evaluated for their activity against kinetoplastid parasites. formation of the oxadiazole ring was accomplished through the reaction of benzamidoximes with acyl chlorides, while the thiocyanate group was inserted by reacting the appropriate 5-halomethyl oxadiazole with ammonium thiocyanate. the thiocyanate-containing compounds possessed low micromolar activity against leishmania donovani and trypanosoma br ... | 2004 | 15142541 |
| protein targeting of an unusual, evolutionarily conserved adenylate kinase to a eukaryotic flagellum. | the eukaryotic flagellum is a large structure into which specific constituent proteins must be targeted, transported and assembled after their synthesis in the cytoplasm. using trypanosoma brucei and a proteomic approach, we have identified and characterized a novel set of adenylate kinase proteins that are localized to the flagellum. these proteins represent unique isoforms that are targeted to the flagellum by an n-terminal extension to the protein and are incorporated into an extraaxonemal st ... | 2004 | 15146060 |
| complete cycles of bloodstream trypanosome rna editing in vitro. | rna editing in kinetoplastid protists is required for the maturation of mitochondrial pre-mrnas and occurs by protein-catalyzed cycles of uridylate insertion and deletion. during the complex life cycle of trypanosoma brucei this process is differentially regulated in the mammalian bloodstream and insect procyclic stages. complementary guide rnas (grnas) direct editing, but the abundance of these transcripts is not developmentally controlled. the establishment of in vitro systems that recreate ef ... | 2004 | 15146075 |
| minisatellites and mvr-pcr for the individual identification of parasite isolates. | in recent years, a wide variety of biochemical and molecular typing systems have been employed in the study of parasite diversity aimed at investigating the level of genetic diversity and delineating the relationships among different species and subspecies. parasite sequence-specific polymerase chain reaction (pcr)-based genotyping systems are among the most useful tools employed to date, because they can be applied to very small quantities of host-contaminated parasite material and, using repea ... | 2004 | 15153628 |
| a pcr-based method for gene deletion and protein tagging in trypanosoma brucei. | sequence information on the trypanosoma brucei genome is rapidly accumulating. as a consequence, there is a need for techniques to analyze gene function systematically. here, we describe a polymerase chain reaction (pcr)-based method for direct gene deletion and the generation of epitope-tagged fusion proteins. the approach is based on methodologies developed for saccharomyces cerevisiae and involves pcr amplification of a reporter cassette using primers containing flanking sequences specific to ... | 2004 | 15153634 |