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Sent on Friday, 2011 Apr 22Search kinetoplastids OR kinetoplastid OR Kinetoplastida OR "trypanosoma brucei" OR leishmania OR brucei OR leishmaniasis OR "African trypanosomiasis"
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| PubMed Results |
| 1. | Parasitol Res. 2011 Apr 21. [Epub ahead of print]First description of naturally acquired Tritrichomonas foetus infection in a Persian cattery in Spain.Miró G, Hernández L, Montoya A, Arranz-Solís D, Dado D, Rojo-Montejo S, Mendoza-Ibarra JA, Ortega-Mora LM, Pedraza-Díaz S.SourceDepartamento de Sanidad Animal, Facultad de Veterinaria, Universidad Complutense de Madrid, Avda. Puerta de Hierro s/n, 28040, Madrid, Spain, gmiro@vet.ucm.es. AbstractTritrichomonas foetus has been identified as the causative agent of feline intestinal trichomonosis, characterized by clinical signs of chronic large bowel diarrhoea. This disease has been reported in cats from the USA, Europe and Australia. However, its epidemiology is still unclear. The aim of the present study was to describe T. foetus infection in a Persian cattery in Spain. T. foetus infection was sequentially diagnosed in 20 cats by direct faecal smear examined under the microscope, specific culture (In Pouch TF medium) and PCR. A standard coprological sedimentation method was also performed in order to screen for other intestinal parasites in all the cats included. In addition, sera were tested for IgG antibodies against Leishmania infantum, Toxoplasma gondii, and for the detection of feline immunodeficiency virus (FIV) and feline leukaemia virus (FeLV). Five out of 20 cats were positive for T. foetus (25%), two of them by microscopy, culture and PCR and three by culture and PCR. No association was found between T. foetus infection and age or sex. L. infantum and T. gondii seroprevalence rates were 15% and 10%, respectively. The prevalence of FeLV p27 antigen and of FIV antibodies in the study population was zero. Cystoisospora spp. oocysts were detected in one cat. These preliminary results show that the transmission of T. foetus infection in cluster conditions may occur between asymptomatic cats and young or immunocompromised animals. |
| 2. | J Biol Chem. 2011 Apr 20. [Epub ahead of print]A single zinc ion is sufficient for an active Trypanosoma brucei tRNA editing deaminase.Spears JL, Rubio MA, Gaston KW, Wywial E, Strikoudis A, Bujnicki JM, Papavasiliou FN, Alfonzo JD.SourceThe Ohio State University, United States; AbstractEditing of adenosine (A) to inosine (I) at the first anticodon position in tRNA is catalyzed by adenosine deaminases acting on tRNA (ADATs). This essential reaction in bacteria and eukarya permits a single tRNA to decode multiple codons. Bacterial ADATa is a homodimer with two-bound essential Zn(2+). The ADATa crystal structure revealed residues important for substrate binding and catalysis; however, such high-resolution structural information is not available for eukaryotic tRNA deaminases. Despite significant sequence similarity among deaminases, we continue to uncover unexpected functional differences between Trypanosoma brucei ADAT2/3 (TbADAT2/3) and its bacterial counterpart. Previously we demonstrated that TbADAT2/3 is unique in catalyzing two different deamination reactions. Here we show by kinetic analyses and ICP-emission spectrometry that wild type TbADAT2/3 coordinates two Zn(2+) per heterodimer but, unlike any other tRNA deaminase, mutation of one of the key Zn(2+)-coordinating cysteines in TbADAT2 yields a functional enzyme with a single-bound zinc. These data suggest that, at least, TbADAT3 may play a role in catalysis via direct coordination of the catalytic Zn(2+). These observations raise the possibility of an unusual Zn(2+) coordination interface with important implications for the function and evolution of editing deaminases. |
| 3. | J Biol Chem. 2011 Apr 19. [Epub ahead of print]The Leishmania donovani UMP synthase is essential for promastigote viability and has an unusual tetrameric structure that exhibits substrate-controlled oligomerization.French JB, Soysa DR, Yates PA, Boitz JM, Carter NS, Chang B, Ullman B, Ealick SE.SourceCornell University, United States; AbstractThe final two steps of de novo uridine 5'-monophosphate (UMP) biosynthesis are catalyzed by orotate phosphoribosyltransferase (OPRT) and orotidine 5'-monophosphate decarboxylase (OMPDC). In most prokaryotes and simple eukaryotes these two enzymes are encoded by separate genes, while in mammals they are expressed as a bifunctional gene product called UMP synthase (UMPS), with OPRT at the N-terminus and OMPDC at the C-terminus. Leishmania and some closely related organisms also express a bifunctional enzyme for these two steps, but the domain order is reversed relative to mammalian UMPS. In this work we demonstrate that L. donovani (LdUMPS) is an essential enzyme in promastigotes and that it is sequestered in the parasite glycosome. We also present the crystal structure of the LdUMPS in complex with its product, UMP. This structure reveals an unusual tetramer with two head-to-head and two tail-to-tail interactions, resulting in two dimeric OMPDC and two dimeric OPRT functional domains. In addition, we provide structural and biochemical evidence that oligomerization of LdUMPS is controlled by product binding at the OPRT active site. We propose a model for the assembly of the catalytically relevant LdUMPS tetramer and discuss the implications for the structure of mammalian UMPS. |
| 4. | Bioorg Med Chem Lett. 2011 Apr 1. [Epub ahead of print]SAR of 2-amino and 2,4-diamino pyrimidines with in vivo efficacy against Trypanosoma brucei.Peral es JB, Freeman J, Bacchi CJ, Bowling T, Don R, Gaukel E, Mercer L, Moore Iii JA, Nare B, Nguyen TM, Noe RA, Randolph R, Rewerts C, Wring SA, Yarlett N, Jacobs RT.SourceSCYNEXIS Inc., PO Box 12878, Research Triangle Park, NC 27709-2878, USA. AbstractA series of 2,4-diaminopyrimidines was investigated and compounds were found to have in vivo efficacy against Trypanosoma brucei in an acute mouse model. However, in vitro permeability data suggested the 2,4-diaminopyrimidenes would have poor permeability through the blood brain barrier. Consequently a series of 4-desamino analogs were synthesized and found to have improved in vitro permeability. Copyright © 2011 Elsevier Ltd. All rights reserved. |
| 5. | Prog Mol Biol Transl Sci. 2011;101:105-76.Natural history of the eukaryotic chromatin protein methylation system.Aravind L, Abhiman S, Iyer LM.AbstractIn eukaryotes, methylation of nucleosomal histones and other nuclear proteins is a central aspect of chromatin structure and dynamics. The past 15 years have seen an enormous advance in our understanding of the biochemistry of these modifications, and of their role in establishing the epigenetic code. We provide a synthetic overview, from an evolutionary perspective, of the main players in the eukaryotic chromatin protein methylation system, with an emphasis on catalytic domains. Several components of the eukaryotic protein methylation system had their origins in bacteria. In particular, the Rossmann fold protein methylases (PRMTs and DOT1), and the LSD1 and jumonji-related demethylases and oxidases, appear to have emerged in the context of bacterial peptide methylation and hydroxylation systems. These systems were originally involved in synthesis of peptide secondary metabolites, such as antibiotics, toxins, and siderophores. The peptidylarginine deiminases appear to have been acquired by animals from bacterial enzymes that modify cell-surface proteins. SET domain methylases, which display the β-clip fold, apparently first emerged in prokaryotes from the SAF superfamily of carbohydrate-binding domains. However, even in bacteria, a subset of the SET domains might have evolved a chromatin-related role in conjunction with a BAF60a/b-like SWIB domain protein and topoisomerases. By the time of the last eukaryotic common ancestor, multiple SET and PRMT methylases were already in place and are likely to have mediated methylation at the H3K4, H3K9, H3K36, and H4K20 positions, and carried out both asymmetric and symmetric arginine dimethylation. Inference of H3K27 methylation in the ancestral eukaryote appears uncertain, though it was certainly in place a little later in eukaryotic evolution. Current data suggest that unlike SET methylases, which are universally present in eukaryotes, demethylases are not. They appear to be absent in the earliest-branching eukaryotic lineages, and emerged later along with several other chromatin proteins, such as the Dot1-methylase, prior to divergence of the kinetoplastid-heterolobosean lineage from the remaining eukaryotes. This period also corresponds to the point of origin of DNA cytosine methylation by DNMT1. Origin of major lineages of SET domains such as the Trithorax, Su(var)3-9, Ash1, SMYD, and TTLL12 and E(Z) might have played the initial role in the establishment of multiple distinct heterochromatic and euchromatic states that are likely to have been present, in some form, through much of eukaryotic evolution. Elaboration of these chromatin states might have gone hand-in-hand with acquisition of multiple jumonji-related and LSD1-like demethylases, and functional linkages with the DNA methylation and RNAi systems. Throughout eukaryotic evolution, there were several lineage-specific expansions of SET domain proteins, which might be related to a special transcription regulation process in trypanosomes, acquisition of new meiotic recombination hotspots in animals, and methylation and associated modifications of the diatom silaffin proteins involved in silica biomineralization. The use of specific domains to "read" the methylation marks appears to have been present in the ancestral eukaryote itself. Of these the chromo-like domains appear to have been acquired from bacterial secreted proteins that might have a role in binding cell-surface peptides or peptidoglycan. Domain architectures of the primary enzymes involved in the eukaryotic protein methylation system indicate key features relating to interactions with each other and other modifications in chromatin, such as acetylation. They also emphasize the profound functional distinction between the role of demethylation and deacetylation in regulation of chromatin dynamics. Copyright © 2011 Elsevier Inc. All rights reserved. |
| 6. | J Med Chem. 2011 Apr 20. [Epub ahead of print]3-Trifluoromethylquinoxaline N,N'-Dioxides as Anti-trypanosomatid Agents. Identification of Optimal Anti-T. cruzi Agents and Mechanism of Action Studies.Benitez D, Cabrera M, Hernandez P, Boiani L, Lavaggi ML, Di Maio R, Yaluff G, Serna E, Torres S, Ferreira ME, Vera de Bilbao N, Torres E, Pérez-Silanes S, Solano B, Moreno E, Aldana I, Lopez de Cerain A, Cerecetto H, González M, Monge A.AbstractAs a fourth approach of quinoxaline N,N'-dioxides as anti-trypanosomatid agents against T. cruzi and Leishmania, we found extremely active derivatives. The present study allows us to state the correct requirements for obtaining optimal in vitro anti-T. cruzi activity. Derivatives possessing electron-withdrawing substituent in the 2-, 3-, 6-, and 7-positions rendered the most active compounds. With regard to these features, and taking in account their mammal-cytotoxicity, some trifluoromethylquinoxaline N,N'-dioxides have been proposed as candidates for further clinical studies. Consequently, mutagenicity and in vivo analyses were performed with the most promising derivatives. In addition, with regard to the mechanism of action studies, it was demonstrated that mitochondrial dehydrogenases are involved in the anti-T. cruzi activity of the most active derivatives. |
| 7. | Trends Parasitol. 2011 Mar;27(3):115-22. Epub 2011 Feb 1.Extracellular Trypanosoma cruzi calreticulin in the host-parasite interplay.Ramírez G, Valck C, Ferreira VP, López N, Ferreira A.SourcePrograma Disciplinario de Inmunología, ICBM, Facultad de Medicina, Universidad de Chile, Independencia 1027, Santiago, Chile. AbstractCalreticulin (CRT) from vertebrates is a calcium-binding protein present mainly in the endoplasmic reticulum (ER). There, it directs the conformation of proteins and controls calcium levels. This review will focus on several extracellular roles of Trypanosoma cruzi CRT (TcCRT) in relation to its capacity to inhibit the complement system, mediate parasite infectivity, interfere with angiogenesis and, as a possible consequence, with tumor growth. The TcCRT antiangiogenic effect parallels with the capacity of T. cruzi infection to inhibit tumor development in vivo. Thus, the TcCRT, complement, and endothelial cell interactions seem to be an evolutionary adaptation to promote prolonged parasite-host relationships. Copyright © 2010 Elsevier Ltd. All rights reserved. |
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| 8. | PLoS Negl Trop Dis. 2011 Jan 11;5(1):e931.International study to evaluate PCR methods for detection of Trypanosoma cruzi DNA in blood samples from Chagas disease patients.Schijman AG, Bisio M, Orellana L, Sued M, Duffy T, Mejia Jaramillo AM, Cura C, Auter F, Veron V, Qvarnstrom Y, Deborggraeve S, Hijar G, Zulantay I, Lucero RH, Velazquez E, Tellez T, Sanchez Leon Z, Galvão L, Nolder D, Monje Rumi M, Levi JE, Ramirez JD, Zorrilla P, Flores M, Jercic MI, Crisante G, Añez N, De Castro AM, Gonzalez CI, Acosta Viana K, Yachelini P, Torrico F, Robello C, Diosque P, Triana Chavez O, Aznar C, Russomando G, Büscher P, Assal A, Guhl F, Sosa Estani S, DaSilva A, Britto C, Luquetti A, Ladzins J.SourceLaboratorio de Biología Molecular de Enfermedad de Chagas, Instituto de Investigaciones en Ingeniería Genética y Biología Molecular (INGEBI-CONICET), Buenos Aires, Argentina. schijman@dna.uba.ar AbstractBACKGROUND:A century after its discovery, Chagas disease still represents a major neglected tropical threat. Accurate diagnostics tools as well as surrogate markers of parasitological response to treatment are research priorities in the field. The purpose of this study was to evaluate the performance of PCR methods in detection of Trypanosoma cruzi DNA by an external quality evaluation. METHODOLOGY/FINDINGS:An international collaborative study was launched by expert PCR laboratories from 16 countries. Currently used strategies were challenged against serial dilutions of purified DNA from stocks representing T. cruzi discrete typing units (DTU) I, IV and VI (set A), human blood spiked with parasite cells (set B) and Guanidine Hidrochloride-EDTA blood samples from 32 seropositive and 10 seronegative patients from Southern Cone countries (set C). Forty eight PCR tests were reported for set A and 44 for sets B and C; 28 targeted minicircle DNA (kDNA), 13 satellite DNA (Sat-DNA) and the remainder low copy number sequences. In set A, commercial master mixes and Sat-DNA Real Time PCR showed better specificity, but kDNA-PCR was more sensitive to detect DTU I DNA. In set B, commercial DNA extraction kits presented better specificity than solvent extraction protocols. Sat-DNA PCR tests had higher specificity, with sensitivities of 0.05-0.5 parasites/mL whereas specific kDNA tests detected 5.10(-3) par/mL. Sixteen specific and coherent methods had a Good Performance in both sets A and B (10 fg/µl of DNA from all stocks, 5 par/mL spiked blood). The median values of sensitivities, specificities and accuracies obtained in testing the Set C samples with the 16 tests determined to be good performing by analyzing Sets A and B samples varied considerably. Out of them, four methods depicted the best performing parameters in all three sets of samples, detecting at least 10 fg/µl for each DNA stock, 0.5 par/mL and a sensitivity between 83.3-94.4%, specificity of 85-95%, accuracy of 86.8-89.5% and kappa index of 0.7-0.8 compared to consensus PCR reports of the 16 good performing tests and 63-69%, 100%, 71.4-76.2% and 0.4-0.5, respectively compared to serodiagnosis. Method LbD2 used solvent extraction followed by Sybr-Green based Real time PCR targeted to Sat-DNA; method LbD3 used solvent DNA extraction followed by conventional PCR targeted to Sat-DNA. The third method (LbF1) used glass fiber column based DNA extraction followed by TaqMan Real Time PCR targeted to Sat-DNA (cruzi 1/cruzi 2 and cruzi 3 TaqMan probe) and the fourth method (LbQ) used solvent DNA extraction followed by conventional hot-start PCR targeted to kDNA (primer pairs 121/122). These four methods were further evaluated at the coordinating laboratory in a subset of human blood samples, confirming the performance obtained by the participating laboratories. CONCLUSION/SIGNIFICANCE:This study represents a first crucial step towards international validation of PCR procedures for detection of T. cruzi in human blood samples. |
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| 9. | Trends Parasitol. 2011 Mar;27(3):99; author reply 100. Epub 2010 Dec 27.Resolving relationships between Australian trypanosomes using DNA barcoding data.Hamilton PB, Stevens JR. |
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