| standard culture medium allows clonal dilution of trypanosoma brucei procyclic cells after auto-conditioning. | trypanosoma brucei can be cultured in vitro in the mammalian bloodstream form or in the procyclic (pc) form found in the insect vector. bloodstream trypanosomes can be cloned by limiting dilution, but pcs can only be diluted in conditioned medium, i.e., medium in which pc cells have previously been grown. it is shown here that this limitation does not apply to the most commonly used pc cell strain, lister 427, if free radicals are removed from the medium. the reported benefit of conditioning med ... | 2009 | 19059438 |
| patterns in age-seroprevalence consistent with acquired immunity against trypanosoma brucei in serengeti lions. | trypanosomes cause disease in humans and livestock throughout sub-saharan africa. although various species show evidence of clinical tolerance to trypanosomes, until now there has been no evidence of acquired immunity to natural infections. we discovered a distinct peak and decrease in age prevalence of t. brucei s.l. infection in wild african lions that is consistent with being driven by an exposure-dependent increase in cross-immunity following infections with the more genetically diverse spec ... | 2008 | 19065258 |
| antiplasmodial and antitrypanosomal activity of plants from the kingdom of saudi arabia. | the antiplasmodial and antitrypanosomal activity of the methanol extracts of 42 plants collected from the kingdom of saudi arabia and some fractions obtained thereof were evaluated. the antiplasmodial activity was tested in vitro against chloroquine-resistant strain (k1) and sensitive strain (fcr3), and the antitrypanosomal activity was tested in vitro against trypanosoma brucei brucei gutat 3.1 strain. for host cells, the cytotoxicity of the active extracts was also evaluated against the mrc5 h ... | 2009 | 19067114 |
| identification and characterization of nuclear non-canonical poly(a) polymerases from trypanosoma brucei. | regulation of nuclear genome expression in trypanosoma brucei is critical for this protozoan parasite's successful transition between its vertebrate and invertebrate host environments. the canonical eukaryotic circuits such as modulation of transcription initiation, mrna splicing and polyadenylation appear to be nearly non-existent in t. brucei suggesting that the transcriptome is primarily defined by mrna turnover. our previous work has highlighted sequence similarities between terminal rna uri ... | 2009 | 19070634 |
| combining rna interference mutants and comparative proteomics to identify protein components and dependences in a eukaryotic flagellum. | eukaryotic flagella from organisms such as trypanosoma brucei can be isolated and their protein components identified by mass spectrometry. here we used a comparative approach utilizing two-dimensional difference gel electrophoresis and isobaric tags for relative and absolute quantitation to reveal protein components of flagellar structures via ablation by inducible rna interference mutation. by this approach we identified 20 novel components of the paraflagellar rod (pfr). using epitope tagging ... | 2009 | 19074134 |
| the crystal structure of atp-bound phosphofructokinase from trypanosoma brucei reveals conformational transitions different from those of other phosphofructokinases. | the crystal structure of the atp-bound form of the tetrameric phosphofructokinase (pfk) from trypanosoma brucei enables detailed comparisons to be made with the structures of the apoenzyme form of the same enzyme, as well as with those of bacterial atp-dependent and pp(i)-dependent pfks. the active site of t. brucei pfk (which is strictly atp-dependent but belongs to the pp(i)-dependent family by sequence similarities) is a chimera of the two types of pfk. in particular, the active site of t. br ... | 2009 | 19084537 |
| the single mitochondrial porin of trypanosoma brucei is the main metabolite transporter in the outer mitochondrial membrane. | all mitochondria have integral outer membrane proteins with beta-barrel structures including the conserved metabolite transporter vdac (voltage dependent anion channel) and the conserved protein import channel tom40. bioinformatic searches of the trypanosoma brucei genome for either vdac or tom40 identified a single open reading frame, with sequence analysis suggesting that vdacs and tom40s are ancestrally related and should be grouped into the same protein family: the mitochondrial porins. the ... | 2009 | 19091722 |
| the mrb1 complex functions in kinetoplastid rna processing. | mitochondrial (mt) gene expression in trypanosoma brucei entails multiple types of rna processing, including polycistronic transcript cleavage, mrna editing, grna oligouridylation, and mrna polyadenylation, which are catalyzed by various multiprotein complexes. we examined the novel mitochondrial rna-binding 1 (mrb1) complex that has 16 associated proteins, four of which have motifs suggesting rna interaction. rnase treatment or the lack of kdna in mutants resulted in lower mrb1 complex sediment ... | 2009 | 19096045 |
| trypanosoma brucei spliced leader rna maturation by the cap 1 2'-o-ribose methyltransferase and sla1 h/aca snorna pseudouridine synthase complex. | kinetoplastid flagellates attach a 39-nucleotide spliced leader (sl) upstream of protein-coding regions in polycistronic rna precursors through trans splicing. sl modifications include cap 2'-o-ribose methylation of the first four nucleotides and pseudouridine (psi) formation at uracil 28. in trypanosoma brucei, tbmtr1 performs 2'-o-ribose methylation of the first transcribed nucleotide, or cap 1. we report the characterization of an sl rna processing complex with tbmtr1 and the sla1 h/aca small ... | 2009 | 19103757 |
| a comprehensive analysis of trypanosoma brucei mitochondrial proteome. | the composition of the large, single, mitochondrion (mt) of trypanosoma brucei was characterized by ms (2-d lc-ms/ms and gel-lc-ms/ms) analyses. a total of 2897 proteins representing a substantial proportion of procyclic form cellular proteome were identified, which confirmed the validity of the vast majority of gene predictions. the data also showed that the genes annotated as hypothetical (species specific) were overpredicted and that virtually all genes annotated as hypothetical, unlikely are ... | 2009 | 19105172 |
| antibiotics ll-z1272 identified as novel inhibitors discriminating bacterial and mitochondrial quinol oxidases. | to counter antibiotic-resistant bacteria, we screened the kitasato institute for life sciences chemical library with bacterial quinol oxidase, which does not exist in the mitochondrial respiratory chain. we identified five prenylphenols, ll-z1272beta, gamma, delta, epsilon and zeta, as new inhibitors for the escherichia coli cytochrome bd. we found that these compounds also inhibited the e. coli bo-type ubiquinol oxidase and trypanosome alternative oxidase, although these three oxidases are stru ... | 2009 | 19111521 |
| trypanosoma brucei udp-glucose:glycoprotein glucosyltransferase has unusual substrate specificity and protects the parasite from stress. | in this paper, we describe the range of n-linked glycan structures produced by wild-type and glucosidase ii null mutant bloodstream form trypanosoma brucei parasites and the creation and characterization of a bloodstream form trypanosoma brucei udp-glucose:glycoprotein glucosyltransferase null mutant. these analyses highlight peculiarities of the trypanosoma brucei udp-glucose:glycoprotein glucosyltransferase, including an unusually wide substrate specificity, ranging from man(5)glcnac(2) to man ... | 2009 | 19114500 |
| nucleic acid sequence-based amplification with oligochromatography for detection of trypanosoma brucei in clinical samples. | molecular tools, such as real-time nucleic acid sequence-based amplification (nasba) and pcr, have been developed to detect trypanosoma brucei parasites in blood for the diagnosis of human african trypanosomiasis (hat). despite good sensitivity, these techniques are not implemented in hat control programs due to the high cost of the equipment, which is unaffordable for laboratories in developing countries where hat is endemic. in this study, a simplified technique, oligochromatography (oc), was ... | 2009 | 19116352 |
| novel mitochondrial complex ii isolated from trypanosoma cruzi is composed of 12 peptides including a heterodimeric ip subunit. | mitochondrial respiratory enzymes play a central role in energy production in aerobic organisms. they differentiated from the alpha-proteobacteria-derived ancestors by adding noncatalytic subunits. an exception is complex ii (succinate: ubiquinone reductase), which is composed of four alpha-proteobacteria-derived catalytic subunits (sdh1-sdh4). complex ii often plays a pivotal role in adaptation of parasites in host organisms and would be a potential target for new drugs. we purified complex ii ... | 2009 | 19122194 |
| il-10 dampens tnf/inducible nitric oxide synthase-producing dendritic cell-mediated pathogenicity during parasitic infection. | antiparasite responses are associated with the recruitment of monocytes that differentiate to macrophages and dendritic cells at the site of infection. although classically activated monocytic cells are assumed to be the major source of tnf and no during trypanosoma brucei brucei infection, their cellular origin remains unclear. in this study, we show that bone marrow-derived monocytes accumulate and differentiate to tnf/inducible no synthase-producing dendritic cells (tip-dcs) in the spleen, li ... | 2009 | 19124754 |
| toward understanding the conformational dynamics of rna ligation. | members of the genus trypanosoma, which include the pathogenic species trypanosoma brucei and trypanosoma cruzi, edit their post-transcriptional mitochondrial rna via a multiprotein complex called the editosome. in t. brucei, the rna is nicked prior to uridylate insertion and deletion. following editing, nicked rna is religated by one of two rna-editing ligases (tbrel). this study describes a recent 70 ns molecular dynamics simulation of tbrel1, an atp-dependent rna-editing ligase of the nucleot ... | 2009 | 19133737 |
| jbp1 and jbp2 are two distinct thymidine hydroxylases involved in j biosynthesis in genomic dna of african trypanosomes. | genomic dna of african trypanosomes contains a hypermodified thymidine residue termed base j (beta-d-glucosyl-homedu). this modified base is localized primarily to repetitive dna, namely the telomeres, and is implicated in the regulation of antigenic variation. the base is synthesized in a two-step pathway. initially, a thymidine residue in dna is hydroxylated by a thymidine hydroxylase (th). this intermediate (homedu) is then glucosylated to form base j. two proteins involved in j synthesis, jb ... | 2009 | 19136460 |
| hydroxyurea-induced synchronisation of bloodstream stage trypanosoma brucei. | synchronisation of the trypanosoma brucei cell cycle proved elusive for many years. a recent report demonstrated that synchronisation of procyclic form cells was possible following treatment with hydroxyurea. here, that work is extended to the disease-relevant, mammalian-infective bloodstream stage trypanosome. treatment of bloodstream stage lister 427 t. brucei cells growing in vitro with 10 microg ml(-1) hydroxyurea for 6h led to an enrichment of cells in s phase. following removal of the drug ... | 2009 | 19150633 |
| the marine sponge diacarnus bismarckensis as a source of peroxiterpene inhibitors of trypanosoma brucei, the causative agent of sleeping sickness. | human african trypanosomiasis, also known as african sleeping sickness, is a neglected tropical disease with inadequate therapeutic options. we have launched a collaborative new lead discovery venture using our repository of extracts and natural product compounds as input into our growth inhibition primary screen against trypanosoma brucei. careful evaluation of the spectral data of the natural products and derivatives allowed for the elucidation of the absolute configuration (using the modified ... | 2009 | 19159277 |
| rna pol ii subunit rpb7 is required for rna pol i-mediated transcription in trypanosoma brucei. | in the protozoan parasite trypanosoma brucei, the two main surface glycoprotein genes are transcribed by rna polymerase i (pol i) instead of rna pol ii, the polymerase committed to the production of mrna in eukaryotes. this unusual feature might be accomplished by the recruitment of specific subunits or cofactors that allow pol i to transcribe protein-coding rnas. here, we report that transcription mediated by pol i requires tbrpb7, a dissociable subunit of the pol ii complex. tbrpb7 was found t ... | 2009 | 19165144 |
| in vitro and in vivo antitrypanosomal activitiy of two microbial metabolites, ks-505a and alazopeptin. | our on-going screening program to discover new antitrypanosomal antibiotics has been evaluating compounds isolated from soil microorganisms as well as investigating the antibiotic libraries of the kitasato institute for life sciences and biofrontier laboratories of kyowa hakko kogyo co., ltd. we have now discovered two compounds, ks-505a and alazopeptin, which exhibit moderate antitrypanosomal characteristics. we report here the in vitro and in vivo antitrypanosomal activities and cytotoxicities ... | 2008 | 19168977 |
| identification and specific localization of tyrosine-phosphorylated proteins in trypanosoma brucei. | phosphorylation on tyrosine residues is a key signal transduction mechanism known to regulate intercellular and intracellular communication in multicellular organisms. despite the lack of conventional tyrosine kinases in the genome of the single cell organism trypanosoma brucei, phosphorylation on trypanosomal protein tyrosine residues has been reported for this parasite. however, the identities of most of the tyrosine-phosphorylated proteins and their precise site(s) of phosphorylation were unk ... | 2009 | 19181871 |
| functional characterization of cohesin smc3 and separase and their roles in the segregation of large and minichromosomes in trypanosoma brucei. | minichromosomes in the nuclear genome of trypanosoma brucei exhibit unusual patterns of mitotic segregation. to address whether differences in their mode of segregation in relation to large chromosomes are reflected at a molecular level, we characterized two different proteins that have highly conserved functions in eukaryotic chromosomes segregation: the smc3 protein, a component of the chromatid cohesion apparatus, and the protease separase that resolves the cohesin complex at the onset of ana ... | 2009 | 19183276 |
| microtubule-severing proteins are involved in flagellar length control and mitosis in trypanosomatids. | microtubules are key players in the biology of trypanosomatid parasites, not only as classical components of the mitotic spindle, microtubule-organizing centres and flagellum but also as the essential constituent of the cytoskeleton. their length dynamics are regulated by, among others, microtubule-severing proteins. four and six genes encoding microtubule-severing proteins can be found bioinformatically in the leishmania major and trypanosoma brucei genome respectively. we investigated all thes ... | 2009 | 19183280 |
| identification, characterization and essentiality of the unusual peroxin 13 from trypanosoma brucei. | peroxin 13 (pex13) is one of the components of a peroxisomal membrane complex involved in import of proteins into the matrix of the organelles and has previously been characterized in a variety of organisms. trypanosomatids (trypanosoma, leishmania), protozoan parasites having peroxisome-like organelles designated glycosomes, possess an unusual pex13 which shares very low sequence identity with others and lacks some typical pex13 characteristics. it was identified in the databases through its mu ... | 2009 | 19185591 |
| kinetoplastid rna editing involves a 3' nucleotidyl phosphatase activity. | mitochondrial pre-messenger rnas (pre-mrnas) in african trypanosomes require rna editing in order to mature into functional transcripts. the process involves the addition and/or removal of u nucleotides and is mediated by a high-molecular-mass complex, the editosome. editosomes catalyze the reaction through an enzyme-driven pathway that includes endo/exoribonuclease, terminal uridylate transferase and rna ligase activities. here we show that editing involves an additional reaction step, a 3' nuc ... | 2009 | 19190092 |
| killing of trypanosomatid parasites by a modified bovine host defense peptide, bmap-18. | tropical diseases caused by parasites continue to cause socioeconomic devastation that reverberates worldwide. there is a growing need for new control measures for many of these diseases due to increasing drug resistance exhibited by the parasites and problems with drug toxicity. one new approach is to apply host defense peptides (hdp; formerly called antimicrobial peptides) to disease control, either to treat infected hosts, or to prevent disease transmission by interfering with parasites in th ... | 2009 | 19190729 |
| post-translational import of protein into the endoplasmic reticulum of a trypanosome: an in vitro system for discovery of anti-trypanosomal chemical entities. | hat (human african trypanosomiasis), caused by the protozoan parasite trypanosoma brucei, is an emerging disease for which new drugs are needed. expression of plasma membrane proteins [e.g. vsg (variant surface glycoprotein)] is crucial for the establishment and maintenance of an infection by t. brucei. transport of a majority of proteins to the plasma membrane involves their translocation into the er (endoplasmic reticulum). thus inhibition of protein import into the er of t. brucei would be a ... | 2009 | 19196237 |
| prostanoid production in saccharomyces cerevisiae provides a novel assay for nonsteroidal anti-inflammatory drugs. | prostanoids are a large family of lipid mediators originating from prostaglandin h synthase (pghs) activity on the 20-carbon polyunsaturated fatty acids dihomo-gamma-linolenic acid (dgla), arachidonic acid (aa) and eicosapentaenoic acid. the two mouse pghs isoforms, pghs-1 and pghs-2, were expressed in saccharomyces cerevisiae (yeast), as was a signal-peptide-deleted version of pghs-1 (pghs-1ma). pghs-1 showed high activity with both aa and dgla as substrate, whereas pghs-2 activity was high wit ... | 2009 | 19207291 |
| ultrastructural study of golgi duplication in trypanosoma brucei. | golgi duplication in the protozoan parasite trypanosoma brucei has been tracked using serial thin section three-dimensional reconstructions of transmission electron micrographs. the old golgi maintains a constant size (approximately 0.060 microm(3)) throughout the cell cycle. a morphologically identifiable new golgi appears at approximately 0.20 of the cell cycle (defined by the size of the nucleus and lasting about 9 h) and grows from approximately 0.018 microm(3) until it is the same size as t ... | 2009 | 19207482 |
| first small molecular inhibitors of t. brucei dolicholphosphate mannose synthase (dpms), a validated drug target in african sleeping sickness. | drug-like molecules with activity against trypanosoma brucei are urgently required as potential therapeutics for the treatment of african sleeping sickness. starting from known inhibitors of other glycosyltransferases, we have developed the first small molecular inhibitors of dolicholphosphate mannose synthase (dpms), a mannosyltransferase critically involved in glycoconjugate biosynthesis in t. brucei. we show that these dpms inhibitors prevent the biosynthesis of glycosylphosphatidylinositol ( ... | 2009 | 19217283 |
| multiple roles for polypyrimidine tract binding (ptb) proteins in trypanosome rna metabolism. | trypanosomatid genomes encode for numerous proteins containing an rna recognition motif (rrm), but the function of most of these proteins in mrna metabolism is currently unknown. here, we report the function of two such proteins that we have named ptb1 and ptb2, which resemble the mammalian polypyrimidine tract binding proteins (ptb). rnai silencing of these factors indicates that both are essential for life. ptb1 and ptb2 reside mostly in the nucleus, but are found in the cytoplasm, as well. mi ... | 2009 | 19218552 |
| unsaturated mannich bases active against multidrug-resistant trypanosoma brucei brucei strains. | a series of unsaturated mannich bases possessing two electrophilic sites was recently identified as irreversible inhibitors of trypanothione reductase from trypanosoma cruzi. new derivatives were synthesized by modifying the substitution pattern on the aromatic ring and by incorporating the melamine motif of melarsoprol. their affinity to p2 transporter and their trypanocidal properties have been studied using three strains expressing various purine transporters. while the melamine derivatives s ... | 2009 | 19219843 |
| trypanosome tor complex 2 functions in cytokinesis. | tor (target of rapamycin) is a kinase of the phosphatidylinositol kinase-related kinase (pikk) family that controls cell growth in eukaryotes in response to nutrients, energy conditions and growth factors. we have recently identified two trypanosome tor orthologs, named tbtor1 and tbtor2, and two other proteins with significant homology to yeast or mammalian tors, named tbtor-like 1 and tbtor-like 2. tbtor1 depletion results in arrest of bloodstream trypanosomes in g(1), concomitant to protein s ... | 2009 | 19221474 |
| major surface glycoproteins of insect forms of trypanosoma brucei are not essential for cyclical transmission by tsetse. | procyclic forms of trypanosoma brucei reside in the midgut of tsetse flies where they are covered by several million copies of glycosylphosphatidylinositol-anchored proteins known as procyclins. it has been proposed that procyclins protect parasites against proteases and/or participate in tropism, directing them from the midgut to the salivary glands. there are four different procyclin genes, each subject to elaborate levels of regulation. to determine if procyclins are essential for survival an ... | 2009 | 19223969 |
| kinetoplastid guide rna biogenesis is dependent on subunits of the mitochondrial rna binding complex 1 and mitochondrial rna polymerase. | the mitochondrial rna binding complex 1 (mrb1) is a recently discovered complex of proteins associated with the tbrgg1 and tbrgg2 proteins in trypanosoma brucei. based on the phenotype caused by down-regulation of these two proteins, it was proposed to play an unspecified role in rna editing. rnai silencing of three newly characterized protein subunits, guide rna associated proteins (gaps) 1 and 2 as well as a predicted dexd/h-box rna helicase, show they are essential for cell growth in the proc ... | 2009 | 19228586 |
| inhibition of trypanosoma brucei glucose-6-phosphate dehydrogenase by human steroids and their effects on the viability of cultured parasites. | dehydroepiandrosterone (dhea) is known as an intermediate in the synthesis of mammalian steroids and a potent uncompetitive inhibitor of mammalian glucose-6-phosphate dehydrogenase (g6pdh), but not the enzyme from plants and lower eukaryotes. g6pdh catalyzes the first step of the pentose-phosphate pathway supplying cells with ribose 5-phosphate, a precursor of nucleic acid synthesis, and nadph for biosynthetic processes and protection against oxidative stress. in this paper we demonstrate that a ... | 2009 | 19231202 |
| leptoclinidamines a-c, indole alkaloids from the australian ascidian leptoclinides durus. | three new indole alkaloids, leptoclinidamines a-c (1-3), were isolated from the australian ascidian leptoclinides durus. their structures were determined by analysis of 2d nmr spectra. leptoclinidamines a and b both contain an indoleglyoxylic acid attached to an l-arginine. the structure of leptoclinidamine a was confirmed by total synthesis. leptoclinidamine c contains the naturally rare 1,3-dimethyl-5-(methylthio)histidine attached to a 6-bromoindole-3-carboxylic acid. leptoclinidamine c (3) a ... | 2009 | 19236031 |
| identification of a palmitoyl acyltransferase required for protein sorting to the flagellar membrane. | protein palmitoylation has diverse effects in regulating protein membrane affinity, localization, binding partner interactions, turnover and function. here, we show that palmitoylation also contributes to the sorting of proteins to the eukaryotic flagellum. african trypanosomes are protozoan pathogens that express a family of unique ca(2+)-binding proteins, the calflagins, which undergo n-terminal myristoylation and palmitoylation. the localization of calflagins depends on their acylation status ... | 2009 | 19240115 |
| a novel function for the atypical small g protein rab-like 5 in the assembly of the trypanosome flagellum. | the atypical small g protein rab-like 5 has been shown to traffic in sensory cilia of caenorhabditis elegans, where it participates in signalling processes but not in cilia construction. in this report, we demonstrate that rabl5 colocalises with intraflagellar transport (ift) proteins at the basal body and in the flagellum matrix of the protist trypanosoma brucei. rabl5 fused to gfp exhibits anterograde movement in the flagellum of live trypanosomes, suggesting it could be associated with ift. a ... | 2009 | 19240117 |
| flagellar membrane localization via association with lipid rafts. | the eukaryotic flagellar membrane has a distinct composition from other domains of the plasmalemma. our work shows that the specialized composition of the trypanosome flagellar membrane reflects increased concentrations of sterols and saturated fatty acids, correlating with direct observation of high liquid order by laurdan fluorescence microscopy. these findings indicate that the trypanosome flagellar membrane possesses high concentrations of lipid rafts: discrete regions of lateral heterogenei ... | 2009 | 19240119 |
| solution structure of urm1 from trypanosoma brucei. | | 2009 | 19241476 |
| differential trypanosome surface coat regulation by a ccch protein that co-associates with procyclin mrna cis-elements. | the genome of trypanosoma brucei is unusual in being regulated almost entirely at the post-transcriptional level. in terms of regulation, the best-studied genes are procyclins, which encode a family of major surface gpi-anchored glycoproteins (ep1, ep2, ep3, gpeet) that show differential expression in the parasite's tsetse-fly vector. although procyclin mrna cis-regulatory sequences have provided the paradigm for post-transcriptional control in kinetoplastid parasites, trans-acting regulators of ... | 2009 | 19247446 |
| targeted delivery of compounds to trypanosoma brucei using the melamine motif. | there is an urgent need for the development of new drugs for the treatment of human african trypanosomiasis. the causative organism, trypanosoma brucei, has been shown to have some unusual plasma membrane transporters, in particular the p2 aminopurine transporter and related permeases, which have been used for the selective targeting of trypanocidal compounds to the organism. in this paper, we report the addition of melamine-based p2-targeting motifs to three different classes of compound in ord ... | 2009 | 19250832 |
| a type iii protein arginine methyltransferase from the protozoan parasite trypanosoma brucei. | arginine methylation is a widespread post-translational modification of proteins catalyzed by a family of protein arginine methyltransferases (prmts). the ancient protozoan parasite, trypanosoma brucei, possesses five putative prmts, a relatively large number for a single-celled eukaryote. trypanosomatids lack gene regulation at the level of transcription, instead relying on post-transcriptional control mechanisms that act at the levels of rna turnover, translation, and editing, all processes th ... | 2009 | 19254949 |
| pentamidine movement across the murine blood-brain and blood-cerebrospinal fluid barriers: effect of trypanosome infection, combination therapy, p-glycoprotein, and multidrug resistance-associated protein. | during the first stage of human african trypanosomiasis (hat), trypanosoma brucei gambiense is found mainly in the blood, and pentamidine treatment is used. pentamidine is predominantly ineffective once the parasites have invaded the central nervous system (cns). this lack of efficacy is thought to be due to the inability of pentamidine to cross the blood-brain barrier, although this has never been explored directly. this study addresses this using brain perfusion in healthy mice, p-glycoprotein ... | 2009 | 19261919 |
| the canonical pathway for selenocysteine insertion is dispensable in trypanosomes. | the micronutrient selenium is found in proteins as selenocysteine (sec), the 21st amino acid cotranslationally inserted in response to a uga codon. in vitro studies in archaea and mouse showed that sec-trna(sec) formation is a 3-step process starting with serylation of trna(sec) by seryl-trna synthetase (serrs), phosphorylation of serine to form phosphoserine (sep)-trna(sec) by phosphoseryl-trna(sec) kinase (pstk), and conversion to sec-trna(sec) by sep-trna:sec-trna synthase (sepsecs). however, ... | 2009 | 19279205 |
| identification of total and differentially expressed excreted-secreted proteins from trypanosoma congolense strains exhibiting different virulence and pathogenicity. | animal trypanosomosis is a major constraint to livestock productivity in the tropics and has a significant impact on the life of millions of people globally (mainly in africa, south america and south-east asia). in africa, the disease in livestock is caused mainly by trypanosoma congolense, trypanosoma vivax, trypanosoma evansi and trypanosoma brucei brucei. the extracellular position of trypanosomes in the bloodstream of their host requires consideration of both the parasite and its naturally e ... | 2009 | 19285981 |
| novel s-adenosylmethionine decarboxylase inhibitors for the treatment of human african trypanosomiasis. | trypanosomiasis remains a significant disease across the sub-saharan african continent, with 50,000 to 70,000 individuals infected. the utility of current therapies is limited by issues of toxicity and the need to administer compounds intravenously. we have begun a program to pursue lead optimization around mdl 73811, an irreversible inhibitor of s-adenosylmethionine decarboxylase (adometdc). this compound is potent but in previous studies cleared rapidly from the blood of rats (t. l. byers, t. ... | 2009 | 19289530 |
| three-dimensional cellular architecture of the flagellar pocket and associated cytoskeleton in trypanosomes revealed by electron microscope tomography. | this study uses electron tomography linked to a variety of other em methods to provide an integrated view of the flagellar pocket and basal body area of the african trypanosome procyclic trypomastigote. we reveal the pocket as an asymmetric membranous 'balloon' with two boundary structures. one of these - the collar - defines the flagellum exit point. the other defines the entry point of the flagellum into the pocket and consists of both an internal transitional fibre array and an external membr ... | 2009 | 19299460 |
| rna interference-mediated silencing of ornithine decarboxylase and spermidine synthase genes in trypanosoma brucei provides insight into regulation of polyamine biosynthesis. | polyamine biosynthesis is a drug target for the treatment of african sleeping sickness; however, mechanisms regulating the pathway in trypanosoma brucei are not well understood. recently, we showed that rna interference (rnai)-mediated gene silencing or the inhibition of s-adenosylmethionine decarboxylase (adometdc) led to the upregulation of the adometdc activator, prozyme, and ornithine decarboxylase (odc) proteins. to determine if this regulatory response is specific to adometdc, we studied t ... | 2009 | 19304951 |
| synthetic nonamer peptides derived from insect defensin mediate the killing of african trypanosomes in axenic culture. | synthetic antimicrobial 9-mer peptides (designated as peptides a and b) designed on the basis of insect defensins and their effects on the growth of african trypanosomes were examined using two isolates of trypanosoma congolense, il1180 and il3338, and two isolates of trypanosoma brucei brucei, iltat1.1and gutat 3.1, under axenic culture conditions. both peptides inhibited the growth of all bloodstream form (bsf) trypanosomes at 200-400 microg/ml in the complete growth medium, with peptide a bei ... | 2009 | 19308456 |
| lipophilic bisphosphonates as dual farnesyl/geranylgeranyl diphosphate synthase inhibitors: an x-ray and nmr investigation. | considerable effort has focused on the development of selective protein farnesyl transferase (ftase) and protein geranylgeranyl transferase (ggtase) inhibitors as cancer chemotherapeutics. here, we report a new strategy for anticancer therapeutic agents involving inhibition of farnesyl diphosphate synthase (fpps) and geranylgeranyl diphosphate synthase (ggpps), the two enzymes upstream of ftase and ggtase, by lipophilic bisphosphonates. due to dual site targeting and decreased polarity, the comp ... | 2009 | 19309137 |
| drug screening by crossing membranes: a novel approach to identification of trypanocides. | trypanosomes are a group of protozoan parasites that inflict huge health and economic burdens across the globe. the african trypanosome, trypanosoma brucei, the causative agent of sleeping sickness, has a highly sophisticated mechanism of antigenic variation that facilitates chronic survival in the mammalian host, and also all but eliminates any realistic hope for vaccination-based control. however, trypanosomes are also highly divergent organisms, with many biochemical processes setting them ap ... | 2009 | 19309311 |
| differential functions of two editosome exouases in trypanosoma brucei. | mitochondrial rnas in trypanosomes are edited by the insertion and deletion of uridine (u) nucleotides to form translatable mrnas. editing is catalyzed by three distinct editosomes that contain two related u-specific exonucleases (exouases), krex1 and krex2, with the former present exclusively in kren1 editosomes and the latter present in all editosomes. we show here that repression of krex1 expression leads to a concomitant reduction of kren1 in approximately 20s editosomes, whereas krex2 repre ... | 2009 | 19318463 |
| functional characterization and protein-protein interactions of trypanosome splicing factors u2af35, u2af65 and sf1. | early in the assembly of eukaryotes the branch-point binding protein (bbp, also called sf1) recognizes the branch point sequence, whereas the heterodimer u2af, consisting of a 65 and a 35 kda subunit, contacts the polypyrimidine tract and the ag splice site, respectively. herein, we identified, cloned and expressed the trypanosoma cruzi and trypanosoma brucei u2af35, u2af65 and sf1. trypanosomatid u2af65 strongly diverged from yeast and human homologues. on the contrary, trypanosomatid sf1 was c ... | 2009 | 19320097 |
| the cell cycle as a therapeutic target against trypanosoma brucei: hesperadin inhibits aurora kinase-1 and blocks mitotic progression in bloodstream forms. | aurora kinase family members co-ordinate a range of events associated with mitosis and cytokinesis. anti-cancer therapies are currently being developed against them. here, we evaluate whether aurora kinase-1 (tbauk1) from pathogenic trypanosoma brucei might be targeted in anti-parasitic therapies as well. conditional knockdown of tbauk1 within infected mice demonstrated its essential contribution to infection. an in vitro kinase assay was developed which used recombinant trypanosome histone h3 a ... | 2009 | 19320832 |
| membrane permeabilization by trypanosome lytic factor, a cytolytic human high density lipoprotein. | trypanosome lytic factor (tlf) is a subclass of human high density lipoprotein (hdl) that mediates an innate immune killing of certain mammalian trypanosomes, most notably trypanosoma brucei brucei, the causative agent of a wasting disease in cattle. mechanistically, killing is initiated in the lysosome of the target trypanosome where the acidic ph facilitates a membrane-disrupting activity by tlf. here we utilize a model liposome system to characterize the membrane binding and permeabilizing ac ... | 2009 | 19324878 |
| evaluation of anti-sleeping-sickness drugs and topoisomerase inhibitors in combination on trypanosoma brucei. | | 2009 | 19336455 |
| the fip-1 like polyadenylation factor in trypanosomes and the structural basis for its interaction with cpsf30. | in trypanosomes transcription is polycistronic and individual mrnas are generated by a trans-splicing/polyadenylation coupled reaction. we identified a divergent trypanosome fip1-like, a factor required for mrna 3' end formation from yeasts to human. here we showed that it is a nuclear protein with a speckled distribution essential for trypanosome viability. a strong interaction was found between tcfip1-like and tccpsf30, a component of the polyadenylation complex. we determined the specific ami ... | 2009 | 19338765 |
| kynurenine pathway inhibition reduces central nervous system inflammation in a model of human african trypanosomiasis. | human african trypanosomiasis, or sleeping sickness, is caused by the protozoan parasites trypanosoma brucei rhodesiense or trypanosoma brucei gambiense, and is a major cause of systemic and neurological disability throughout sub-saharan africa. following early-stage disease, the trypanosomes cross the blood-brain barrier to invade the central nervous system leading to the encephalitic, or late stage, infection. treatment of human african trypanosomiasis currently relies on a limited number of h ... | 2009 | 19339256 |
| solution structure of sumo from trypanosoma brucei and its interaction with ubc9. | | 2009 | 19343802 |
| antitrypanosomal activity of some pregnane glycosides isolated from caralluma species. | pregnane glycosides previously isolated from genus caralluma (c. penicillata, c. tuberculata and c. russelliana) were tested for their antitrypanosomal activity. penicilloside e showed the highest antitrypanosomal activity (ic(50) 1.01 microg/ml) followed by caratuberside c (ic(50) 1.85 microg/ml), which exhibited the highest selectivity index (si 12.04). it was noticed that acylation is required for the antitrypanosomal activity while glycosylation at c-20 has no significant effect on the activ ... | 2009 | 19345077 |
| rap1 is essential for silencing telomeric variant surface glycoprotein genes in trypanosoma brucei. | trypanosoma brucei expresses variant surface glycoprotein (vsg) genes in a strictly monoallelic fashion in its mammalian hosts, but it is unclear how this important virulence mechanism is enforced. telomere position effect, an epigenetic phenomenon, has been proposed to play a critical role in vsg regulation, yet no telomeric protein has been identified whose disruption led to vsg derepression. we now identify tbrap1 as an intrinsic component of the t. brucei telomere complex and a major regulat ... | 2009 | 19345190 |
| insights into the enzymatic mechanism of 6-phosphogluconolactonase from trypanosoma brucei using structural data and molecular dynamics simulation. | trypanosoma brucei is the causative agent of african sleeping sickness. current work for the development of new drugs against this pathology includes evaluation of enzymes of the pentose phosphate pathway (ppp), which first requires a clear understanding of their function and mechanism of action. in this context, we focused on t. brucei 6-phosphogluconolactonase (tb6pgl), which converts delta-6-phosphogluconolactone into 6-phosphogluconic acid in the second step of the ppp. we have determined th ... | 2009 | 19345229 |
| the phosphoproteome of bloodstream form trypanosoma brucei, causative agent of african sleeping sickness. | the protozoan parasite trypanosoma brucei is the causative agent of human african sleeping sickness and related animal diseases, and it has over 170 predicted protein kinases. protein phosphorylation is a key regulatory mechanism for cellular function that, thus far, has been studied in t.brucei principally through putative kinase mrna knockdown and observation of the resulting phenotype. however, despite the relatively large kinome of this organism and the demonstrated essentiality of several t ... | 2009 | 19346560 |
| both type-i and type-ii responses contribute to murine trypanotolerance. | the host immune system has been documented to influence the course and outcome of infection with the phospholipase-c-deficient (plc(-/-)) trypanosoma brucei brucei. we addressed the resistant mechanisms during trypanosomosis by comparing the immune response to variant-specific surface glycoprotein (vsg) in relatively susceptible c3h mice and trypanotolerant (c57bl/6 x balb/c)-f1 (b6b-f1) mice infected with plc(-/-) parasites. during the early stage of infection, lymphoid cells from both plc(-/-) ... | 2009 | 19346699 |
| genetics. leishmania exploit sex. | | 2009 | 19359570 |
| four histone variants mark the boundaries of polycistronic transcription units in trypanosoma brucei. | unusually for a eukaryote, genes transcribed by rna polymerase ii (pol ii) in trypanosoma brucei are arranged in polycistronic transcription units. with one exception, no pol ii promoter motifs have been identified, and how transcription is initiated remains an enigma. t. brucei has four histone variants: h2az, h2bv, h3v, and h4v. using chromatin immunoprecipitation (chip) and sequencing (chip-seq) to examine the genome-wide distribution of chromatin components, we show that histones h4k10ac, h2 ... | 2009 | 19369410 |
| a yeast-endonuclease-generated dna break induces antigenic switching in trypanosoma brucei. | trypanosoma brucei is the causative agent of african sleeping sickness in humans and one of the causes of nagana in cattle. this protozoan parasite evades the host immune system by antigenic variation, a periodic switching of its variant surface glycoprotein (vsg) coat. vsg switching is spontaneous and occurs at a rate of about 10(-2)-10(-3) per population doubling in recent isolates from nature, but at a markedly reduced rate (10(-5)-10(-6)) in laboratory-adapted strains. vsg switching is thoug ... | 2009 | 19369939 |
| homology modeling and molecular dynamics simulation of n-myristoyltransferase from protozoan parasites: active site characterization and insights into rational inhibitor design. | myristoyl-coa:protein n-myristoyltransferase (nmt) is a cytosolic monomeric enzyme that catalyzes the transfer of the myristoyl group from myristoyl-coa to the n-terminal glycine of a number of eukaryotic cellular and viral proteins. recent experimental data suggest nmt from parasites could be a promising new target for the design of novel antiparasitic agents with new mode of action. however, the active site topology and inhibitor specificity of these enzymes remain unclear. in this study, thre ... | 2009 | 19370313 |
| comparative molecular docking of antitrypanosomal natural products into multiple trypanosoma brucei drug targets. | antitrypanosomal natural products with different structural motifs previously shown to have growth inhibitory activity against trypanosoma brucei were docked into validated drug targets of the parasite, which include trypanothione reductase, rhodesain, farnesyl diphosphate synthase, and triosephosphate isomerase. the in-silico calculations predicted that lowest energy docked poses of a number of the compounds can interact with catalysis-dependent residues, thus making them possible catalytic inh ... | 2009 | 19384282 |
| systematic structural studies of iron superoxide dismutases from human parasites and a statistical coupling analysis of metal binding specificity. | superoxide dismutases (sods) are a crucial class of enzymes in the combat against intracellular free radical damage. they eliminate superoxide radicals by converting them into hydrogen peroxide and oxygen. in spite of their very different life cycles and infection strategies, the human parasites plasmodium falciparum, trypanosoma cruzi and trypanosoma brucei are known to be sensitive to oxidative stress. thus the parasite fe-sods have become attractive targets for novel drug development. here we ... | 2009 | 19384994 |
| the aignopsanes, a new class of sesquiterpenes from selected chemotypes of the sponge cacospongia mycofijiensis. | a survey of individual specimens of northern papua new guinea derived cacospongia mycofijiensis has yielded novel sesquiterpenes, aignopsanoic acid a (1), methyl aignopsanoate a (2), and isoaignopsanoic acid a (3). the structures and absolute configurations of 1-3 were established using nmr data, x-ray crystallography results, and an analysis of cd properties. two of these metabolites, 1 and 2, were moderately active against trypanosoma brucei, the parasite responsible for sleeping sickness. | 2009 | 19385671 |
| dual targeting of a trnaasp requires two different aspartyl-trna synthetases in trypanosoma brucei. | the mitochondrion of the parasitic protozoon trypanosoma brucei does not encode any trnas. this deficiency is compensated for by partial import of nearly all of its cytosolic trnas. most trypanosomal aminoacyl-trna synthetases are encoded by single copy genes, suggesting the use of the same enzyme in the cytosol and in the mitochondrion. however, the t. brucei genome encodes two distinct genes for eukaryotic aspartyl-trna synthetase (asprs), although the cell has a single trnaasp isoacceptor onl ... | 2009 | 19386587 |
| transcriptionally active tfiih of the early-diverged eukaryote trypanosoma brucei harbors two novel core subunits but not a cyclin-activating kinase complex. | trypanosoma brucei is a member of the early-diverged, protistan family trypanosomatidae and a lethal parasite causing african sleeping sickness in humans. recent studies revealed that t. brucei harbors extremely divergent orthologues of the general transcription factors tbp, tfiia, tfiib and tfiih and showed that these factors are essential for initiating rna polymerase ii-mediated synthesis of spliced leader (sl) rna, a trans splicing substrate and key molecule in trypanosome mrna maturation. i ... | 2009 | 19386623 |
| perturbation of phosphatidylethanolamine synthesis affects mitochondrial morphology and cell-cycle progression in procyclic-form trypanosoma brucei. | phosphatidylethanolamine (pe) and phosphatidylcholine (pc) are the two major constituents of eukaryotic cell membranes. in the protist trypanosoma brucei, pe and pc are synthesized exclusively via the kennedy pathway. to determine which organelles or processes are most sensitive to a disruption of normal phospholipid levels, the cellular consequences of a decrease in the levels of pe or pc, respectively, were studied following rnai knock-down of four enzymes of the kennedy pathway. rnai against ... | 2009 | 19400804 |
| towards a new reference test for surra in camels. | current serological diagnosis of trypanosoma evansi infection in camels is based on the native variable antigen type rotat 1.2. the goal of this study was to develop a novel serological diagnostic test based on a nonvariable protein and freed from the use of rats or mice for its production. an enzyme-linked immunosorbent assay using a recombinant extracellular domain of invariant surface glycoprotein 75 (elisa/risg75) was developed and tested on a collection of 184 camel sera. the results were c ... | 2009 | 19403780 |
| in vitro and in vivo antitrypanosomal activities of three peptide antibiotics: leucinostatin a and b, alamethicin i and tsushimycin. | in the course of our screening for antitrypanosomal compounds from soil microorganisms, as well as from the antibiotics library of the kitasato institute for life sciences, we found three peptide antibiotics, leucinostatin (a and b), alamethicin i and tsushimycin, which exhibited potent or moderate antitrypanosomal activity. we report here the in vitro and in vivo antitrypanosomal properties and cytotoxicities of leucinostatin a and b, alamethicin i and tsushimycin compared with suramin. we also ... | 2009 | 19407848 |
| effects of melarsamine hydrochloride (cymelarsan) and diminazene aceturate (berenil) on the pathology of experimental trypanosoma brucei infection in red fronted gazelles (gazella rufifrons). | an experimental infection of red fronted gazelles (gazella rufifrons) with trypanosoma brucei strain mkar/84/nitr/6 was carried out. two waves of parasitaemia which corresponded with a significant decline (p<0.05) in packed cell volume (pcv) was encountered in the infected untreated controls and those treated at day 8 post-infection with a sub-optimal dosage of diminazene aceturate (berenil) at 3.5 mg/kg body weight. at postmortem, hepatomegally, splenomegally, lymphadenopathy, nephritis, myocar ... | 2009 | 19410371 |
| electron microscopy and cytochemistry analysis of the endocytic pathway of pathogenic protozoa. | endocytosis is essential for eukaryotic cell survival and has been well characterized in mammal and yeast cells. among protozoa it is also important for evading from host immune defenses and to support intense proliferation characteristic of some life cycle stages. here we focused on the contribution of morphological and cytochemical studies to the understanding of endocytosis in trichomonas, giardia, entamoeba, plasmodium, and trypanosomatids, mainly trypanosoma cruzi, and also trypanosoma bruc ... | 2009 | 19410686 |
| the single enth-domain protein of trypanosomes; endocytic functions and evolutionary relationship with epsin. | epsin n-terminal homology (enth) domains occur in proteins of either the epsin or epsin-related (epsinr) form. they principally function in clathrin-mediated trafficking and membrane deformation. both epsin and epsinr possess clathrin-binding motifs, but only epsin incorporates a ubiquitin-interaction motif (uim). to better understand the origins of enth-domain proteins and their functions, we performed detailed comparative genomics and phylogenetics on the epsin family. the epsin enth-uim confi ... | 2009 | 19416477 |
| chromatin-based transcriptional punctuation. | the long polycistronic transcription units of trypanosomes do not appear to be demarcated by the usual dna motifs that punctuate transcription in familiar eukaryotes. in this issue of genes & development, siegel and colleagues (pp. 1063-1076) describe a system for the demarcation of trypanosome transcription units based on the deposition and turnover of histone variants rather than on the binding of transcription factors. replication-independent incorporation of histone variants and destabilizat ... | 2009 | 19417102 |
| discovery of new s-adenosylmethionine decarboxylase inhibitors for the treatment of human african trypanosomiasis (hat). | modification of the structure of trypanosomal adometdc inhibitor 1 (mdl73811) resulted in the identification of a new inhibitor 7a, which features a methyl substituent at the 8-position. compound 7a exhibits improved potencies against both the trypanosomal adometdc enzyme and parasites, and better blood brain barrier penetration than 1. | 2009 | 19419862 |
| stability of loop-mediated isothermal amplification (lamp) reagents and its amplification efficiency on crude trypanosome dna templates. | this study evaluated the stability of lamp reagents when stored at 25 degrees c and 37 degrees c, and also assessed its detection efficiency on different dna template preparations. accordingly, lamp using reagents stored at 25 degrees c and 37 degrees c amplified dna of in vitro cultured t. b. brucei (gutat 3.1) from day 1 to day 15 of reagent storage. there were no significant differences (p>0.05) in detection sensitivity of lamp among the reagents stored at 25 degrees c, 37 degrees c and -20 d ... | 2009 | 19420851 |
| design and synthesis of trypanosoma brucei active 1-alkyloxy and 1-benzyloxyadamantano 2-guanylhydrazones. | treating african trypanosomiasis: the synthesis and biological evaluation of novel 1-alkyloxy and 1-benzyloxyadamantano 2-guanylhydrazones, their 1-dioxa congeners and two 1-benzyladamantano 2-guanylhydrazones is reported. preliminary structure-activity relationship data were elucidated and lead compounds suitable for further optimization were discovered. | 2009 | 19422003 |
| spliceosomal proteomics in trypanosoma brucei reveal new rna splicing factors. | in trypanosomatid parasites, spliced leader (sl) trans splicing is an essential nuclear mrna maturation step which caps mrnas posttranscriptionally and, in conjunction with polyadenylation, resolves individual mrnas from polycistronic precursors. while all trypanosomatid mrnas are trans spliced, intron removal by cis splicing is extremely rare and predicted to occur in only four pre-mrnas. trans- and cis-splicing reactions are carried out by the spliceosome, which consists of u-rich small nuclea ... | 2009 | 19429779 |
| the antiprotozoal activity of sixteen asteraceae species native to sudan and bioactivity-guided isolation of xanthanolides from xanthium brasilicum. | in vitro screening of the dichloromethane extracts of 16 asteraceae species native to sudan for activity against major protozoan pathogens revealed that a xanthium brasilicum vell. [syn. x. strumarium var. brasilicum (vell.) baker in mart.] extract was the most active against trypanosoma brucei rhodesiense, the etiological agent of east african human trypanosomiasis (ic(50) = 0.1 microg/ml). this plant extract also exhibited noticeable activities against t. cruzi (chagas disease), leishmania don ... | 2009 | 19431098 |
| the f(0)f(1)-atp synthase complex contains novel subunits and is essential for procyclic trypanosoma brucei. | the mitochondrial f(0)f(1) atp synthase is an essential multi-subunit protein complex in the vast majority of eukaryotes but little is known about its composition and role in trypanosoma brucei, an early diverged eukaryotic pathogen. we purified the f(0)f(1) atp synthase by a combination of affinity purification, immunoprecipitation and blue-native gel electrophoresis and characterized its composition and function. we identified 22 proteins of which five are related to f(1) subunits, three to f( ... | 2009 | 19436713 |
| purification and biochemical characterization of lysosomal acid phosphatases (ec 3.1.3.2) from blood stream forms, trypanosoma brucei brucei. | three acid phosphatases (acp) were isolated and characterized from the lysosomes of blood stream forms of trypanosoma brucei by a combination of isopynic and differential centrifugation through ficoll, organic solvent precipitation, ion exchange on deae cellulose 52 and size exclusion chromatography on sephadex g-75 columns. the purified acp emerged as three distinct peaks (acp i, acp ii and acp iii) with high specific activities and they moved homogeneously on 12% sds-page each as a single band ... | 2009 | 19442761 |
| functional characterization of stage-specific aminotransferases from trypanosomatids. | as part of a study on aminotransferases, genes coding for putative enzymes from trypanosoma brucei and leishmania major (alanine aminotransferases: alats, tb927.1.3950 and lmjf12.0630; kynurenine aminotransferase: kat, tb10.389.1810; and tyrosine aminotransferase: tat, lmjf36.2360) were cloned and functionally expressed in escherichia coli. the putative t. brucei kat, in fact coded for a glutamine aminotransferase (glnat), which exhibited a notably high affinity (in the micromolar range) towards ... | 2009 | 19443056 |
| complex interactions in the regulation of trypanosome mitochondrial gene expression. | trypanosomes undergo extreme physiological changes to adapt to different environments as they cycle between hosts. adaptation to the different environments has evolved an energy metabolism involving a mitochondrion with an unusual genome. recently, aphasizhev and colleagues have identified two new protein complexes, a mitochondrial polyadenylation complex and a guide rna stabilization complex, that provide novel insights into the coordinated expression of the mitochondrial genome. | 2009 | 19443271 |
| molecular microbiology: a key event in survival. | | 2009 | 19444197 |
| microbiology: signals for change. | | 2009 | 19444199 |
| a surface transporter family conveys the trypanosome differentiation signal. | microbial pathogens use environmental cues to trigger the developmental events needed to infect mammalian hosts or transmit to disease vectors. the parasites causing african sleeping sickness respond to citrate or cis-aconitate (cca) to initiate life-cycle development when transmitted to their tsetse fly vector. this requires hypersensitization of the parasites to cca by exposure to low temperature, conditions encountered after tsetse fly feeding at dusk or dawn. here we identify a carboxylate-t ... | 2009 | 19444208 |
| nutritional stress of adult female tsetse flies (diptera: glossinidae) affects the susceptibility of their offspring to trypanosomal infections. | the epidemiology of tsetse-transmitted trypanosomiasis depends, among other factors, on the proportion of infected flies in a tsetse population. a wide range of intrinsic and extrinsic factors seem to determine the ability of a tsetse fly to become infected and to transmit the parasite. in this paper, we investigated the effect of nutritional stress of reproducing female glossina morsitans morsitans on the susceptibility of their offspring to trypanosomal infections. adult female flies that were ... | 2009 | 19445895 |
| the bilobe structure of trypanosoma brucei contains a morn-repeat protein. | the golgi of the kinetoplastid parasite trypanosoma brucei is closely apposed to a bilobe structure containing tbcentrin2 and tbcentrin4 in procyclic cells. however, both are additionally localized to the basal bodies. here we report the characterization of a membrane occupation and recognition nexus (morn)-repeat protein, tbmorn1, present at the bilobe but not at the basal body. the anterior part of the tbmorn1 structure partially overlapped with the flagellar attachment zone while the posterio ... | 2009 | 19445968 |
| uridine insertion/deletion rna editing in trypanosomatid mitochondria: in search of the editosome. | the rna ligase-containing or l-complex is the core complex involved in uridine insertion/deletion rna editing in trypanosome mitochondria. blue native gels of glycerol gradient-separated fractions of mitochondrial lysate from cells transfected with the tap-tagged editing protein, lc-8 (tbmp44/krepb5), show a approximately 1 mda l-complex band and, in addition, two minor higher molecular weight rel1-containing complexes: one (l*a) co-sedimenting with the l-complex and running in the gel at around ... | 2009 | 19447916 |
| gene organization and sequence analyses of transfer rna genes in trypanosomatid parasites. | the protozoan pathogens leishmania major, trypanosoma brucei and trypanosoma cruzi (the tritryps) are parasites that produce devastating human diseases. these organisms show very unusual mechanisms of gene expression, such as polycistronic transcription. we are interested in the study of trna genes, which are transcribed by rna polymerase iii (pol iii). to analyze the sequences and genomic organization of trna genes and other pol iii-transcribed genes, we have performed an in silico analysis of ... | 2009 | 19450263 |
| casein kinase 1 isoform 2 is essential for bloodstream form trypanosoma brucei. | induction of rna interference targeted against casein kinase 1 isoform 2 (tbck1.2, tb927.5.800) in bloodstream form trypanosoma brucei in vitro results in rapid cessation of growth, gross morphological changes, multinucleation and ultimately cell death. a null mutant of the highly homologous casein kinase 1 isoform 1 (tb927.5.790) in bloodstream form t. brucei displays no growth or morphological phenotype in vitro. a truncated form of tbck1.2 expressed in escherichia coli as a gst fusion produce ... | 2009 | 19450734 |