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Sent on Friday, 2010 May 07Search 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. 2010 May 6. [Epub ahead of print]Occurrence of antibodies anti-Neospora caninum, anti-Toxoplasma gondii, and anti-Leishmania chagasi in serum of dogs from Pará State, Amazon, Brazil.Valadas S, Minervino AH, Lima VM, Soares RM, Ortolani EL, Gennari SM.Faculdade de Medicina Veterinária e Zootecnia, Departamento de Medicina Veterinária Preventiva e Saúde Animal, USP, Av. Prof. Orlando Marques de Paiva, 87, Cidade Universitária, CEP 05508-270, São Paulo, São Paulo, Brazil. AbstractA cross-sectional study was conducted to determine the occurrence of anti-Toxoplasma gondii, anti-Neospora caninum, and anti- Leishmania chagasi antibodies in dogs of the state of Pará, Brazil. For this purpose, 129 blood samples were collected from dogs of different ages and gender. Samples of 72 dogs were collected from 39 rural properties from 19 municipalities, and 57 samples were from stray dogs, collected after captivity by the Center of Zoonosis Control from the municipality of Santarém. The sera were analyzed for anti-T. gondii and anti-N. caninum antibodies by indirect fluorescent antibody tests with cutoff values of 1:16 and 1:50, respectively. For the presence of L. chagasi antibodies, enzyme-linked immunosorbent assay was used and positive results were confirmed by immunochromatographic method using the recombinant antigen K39. Of the total of 129 dogs, 90 (69.8%) were positive for T. gondii, 16 (12.4%) for N. caninum, and 30 (23.3%) for L. chagasi. Antibodies for all three parasites were found simultaneously in seven dogs (5.4%), mostly in urban dogs (six of seven). No association was observed related to gender and location (urban or rural) of dogs and occurrence of N. caninum and T. gondii antibodies although, regarding L. chagasi, higher prevalence was found in females (P < 0.02) and in dogs from urban location (P < 0.001). From the 39 farms, in 30 (76.9%) at least one dog was positive for T. gondii or N. caninum or both. Higher occurrence of Leishmania antibodies was observed in N. caninum-negative dogs (P < 0.05). |
| PMID: 20445991 [PubMed - as supplied by publisher] | |
| 2. | Indian J Dermatol Venereol Leprol. 2010 May-Jun;76(3):307.Bilateral cutaneous leishmaniasis presenting as eczema-like eruptions on the hands.Nasiri S, Robati RM, Marefat A, Saeedi M, Sarrafi-rad N. |
| PMID: 20445316 [PubMed - in process] | |
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| 3. | Acta Crystallogr Sect F Struct Biol Cryst Commun. 2010 May 1;66(Pt 5):571-4. Epub 2010 Apr 30.Cloning, expression, purification, crystallization and preliminary X-ray diffraction analysis of glyoxalase I from Leishmania infantum.Barata L, Sousa Silva M, Schuldt L, da Costa G, Tomás AM, Ferreira AE, Weiss MS, Ponces Freire A, Cordeiro C.Centro de Química e Bioquímica, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade de Lisboa, Lisboa, Campo Grande, Edificio C8, 1149-016 Lisboa, Portugal. AbstractGlyoxalase I (GLO1) is the first of the two glyoxalase-pathway enzymes. It catalyzes the formation of S-D-lactoyltrypanothione from the non-enzymatically formed hemithioacetal of methylglyoxal and reduced trypanothione. In order to understand its substrate binding and catalytic mechanism, GLO1 from Leishmania infantum was cloned, overexpressed in Escherichia coli, purified and crystallized. Two crystal forms were obtained: a cube-shaped form and a rod-shaped form. While the cube-shaped form did not diffract X-rays at all, the rod-shaped form exhibited diffraction to about 2.0 A resolution. The crystals belonged to space group P2(1)2(1)2, with unit-cell parameters a = 130.03, b = 148.51, c = 50.63 A and three dimers of the enzyme per asymmetric unit. |
| PMID: 20445262 [PubMed - in process] | |
| 4. | Nucleic Acids Res. 2010 May 5. [Epub ahead of print]tRNASec is transcribed by RNA polymerase II in Trypanosoma brucei but not in humans.Aeby E, Ullu E, Yepiskoposyan H, Schimanski B, Roditi I, Mühlemann O, Schneider A.Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, CH-3012 Bern, Switzerland, Departments of Internal Medicine and Cell Biology, Yale University School of Medicine, New Haven, CT 06536-0812, USA and Institute of Cell Biology, University of Bern, Baltzerstrasse 4, CH-3012 Bern, Switzerland. AbstractNuclear-encoded tRNAs are universally transcribed by RNA polymerase III (Pol-III) and contain intragenic promoters. Transcription of vertebrate tRNA(Sec) however requires extragenic promoters similar to Pol-III transcribed U6 snRNA. Here, we present a comparative analysis of tRNA(Sec) transcription in humans and the parasitic protozoa Trypanosoma brucei, two evolutionary highly diverged eukaryotes. RNAi-mediated ablation of Pol-II and Pol-III as well as oligo-dT induced transcription termination show that the human tRNA(Sec) is a Pol-III transcript. In T. brucei protein-coding genes are polycistronically transcribed by Pol-II and processed by trans-splicing and polyadenylation. tRNA genes are generally clustered in between polycistrons. However, the trypanosomal tRNA(Sec) genes are embedded within a polycistron. Their transcription is sensitive to alpha-amanitin and RNAi-mediated ablation of Pol-II, but not of Pol-III. Ectopic expression of the tRNA(Sec) outside but not inside a polycistron requires an added external promoter. These experiments demonstrate that trypanosomal tRNA(Sec), in contrast to its human counterpart, is transcribed by Pol-II. Synteny analysis shows that in trypanosomatids the tRNA(Sec) gene can be found in two different polycistrons, suggesting that it has evolved twice independently. Moreover, intron-encoded tRNAs are present in a number of eukaryotic genomes indicating that Pol-II transcription of tRNAs may not be restricted to trypanosomatids. |
| PMID: 20444878 [PubMed - as supplied by publisher] | |
| 5. | Nucleic Acids Res. 2010 May 5. [Epub ahead of print]A fluorescence-based reporter substrate for monitoring RNA editing in trypanosomatid pathogens.Moshiri H, Salavati R.Institute of Parasitology, McGill University, 21111 Lakeshore Road, Ste. Anne de Bellevue, Montreal, Quebec H9X3V9, Department of Biochemistry, McGill University, McIntyre Medical Building, 3655 Promenade Sir William Osler, Montreal, Quebec H3G1Y6 and McGill Centre for Bioinformatics, McGill University, Duff Medical Building, 3775 University Street, Montreal, Quebec H3A2B4, Canada. AbstractRNA editing regulates mitochondrial gene expression in trypanosomatid pathogens by creating functional mRNAs. It is catalyzed by a multi-protein complex (the editosome), and is found to be essential in both insect stage and mammalian blood stream form of Trypanosoma brucei. This particular form of RNA editing is unique to trypanosomatids, and thus provides a suitable drug target in trypanosomatid pathogens. Here, we demonstrate the feasibility of a rapid and sensitive fluorescence-based reporter assay to monitor RNA editing based on ribozyme activity. We could validate our new assay using previously identified inhibitors against the essential RNA editing ligase. The principle advantages of this assay are: (i) the use of non-radioactively labeled materials, (ii) sensitivity afforded by fluorescence instrumentation applicable to high-throughput screening of chemical inhibitors against the essential editosome and (iii) a rapid and convenient 'mix and measure' type of assay in low volume with a high signal to noise ratio. This assay should enhance rapid identification and characterization of the editosome inhibitors primarily based on the overall composition of the editosomes from T. brucei. These inhibitors could also be tested against the editosomes from the closely related pathogens including T. cruzi and Leishmania species. |
| PMID: 20444864 [PubMed - as supplied by publisher] | |
| 6. | J Biol Chem. 2010 May 5. [Epub ahead of print]The Trypanosoma brucei life cycle switch TbPTP1 is structurally conserved and dephosphorylates the nucleolar p rotein, NOPP44/46.Chou S, Jensen BC, Parsons M, Alber T, Grundner C.University of California, Berkeley, United States; AbstractTrypanosoma brucei adapts to changing environments as it cycles through arrested and proliferating stages in the human and tsetse fly hosts. Changes in protein tyrosine phosphorylation of several proteins, including NOPP44/46, accompany T. brucei development. Moreover, inactivation of T. brucei protein tyrosine phosphatase 1 (TbPTP1) triggers differentiation of bloodstream stumpy forms into tsetse procyclic forms through unknown downstream effects. Here, we link these events by showing that NOPP44/46 is a major substrate of TbPTP1. TbPTP1 substrate-trapping mutants selectively enrich NOPP44/46 from procyclic stage cell lysates, and TbPTP1 efficiently and selectively dephosphorylates NOPP44/46 in vitro. To provide insights into the mechanism of NOPP44/46 recognition, we determined the crystal structure of TbPTP1. The TbPTP1 structure, the first of a kinetoplastid PTP, emphasizes the conservation of the protein tyrosine phosphatase (PTP) fold, extending to one of the most diverged eukaryotes. The structure reveals surfaces that may mediate substrate specificity and affords a template for the design of selective inhibitors to interfere with T. brucei transmission. |
| PMID: 20444707 [PubMed - as supplied by publisher] | |
| 7. | BMC Genomics. 2010 May 5;11(1):283. [Epub ahead of print]Genome-wide in silico screen for CCCH-type zinc finger proteins of Trypanosoma brucei, Trypanosoma cruzi and Leishmania major.Kramer S, Kimblin NC, Carrington M.AbstractABSTRACT: BACKGROUND: CCCH type zinc finger proteins are RNA binding proteins with regulatory functions at all stages of mRNA metabolism. The best-characterized member, tritetraproline (TTP), binds to AU rich elements in 3' UTRs of unstable mRNAs, mediating their degradation. In kinetoplastids, CCCH type zinc finger proteins have been identified as being involved in the regulation of the life cycle and possibly the cell cycle. To date, no systematic listing of CCCH proteins in kinetoplastids is available. RESULTS: We have identified the complete set of CCCH type zinc finger proteins in the available genomes of the kinetoplastid protozoa Trypanosoma brucei, Trypanosoma cruzi and Leishmania major. One fifths (20%) of all CCCH motifs fall into non-conventional classes and many had not been previously identified. One third of all CCCH proteins have more than one CCCH motif, suggesting multivalent RNA binding. One third have additional recognizable domains. The vast majority are unique to Kinetoplastida or to a subgroup within. Two exceptions are of interest: the putative orthologue of the mRNA nuclear export factor Mex67 and a 3'-5' exoribonuclease restricted to Leishmania species. CCCH motifs are absent from these proteins in other organisms and might be unique, novel features of the Kinetoplastida homologues. Of the others, several have a predicted, and in one case experimentally confirmed, connection to the ubiquitination pathways, for instance a HECT-type E3 ubiquitin ligase. The total number of kinetoplastid CCCH proteins is similar to the number in higher eukaryotes but lower than in yeast. A comparison of the genomic loci between the Trypanosomatidae homologues provides insight into both the evolution of the CCCH proteins as well as the CCCH motifs. CONCLUSION: This study provides the first systematic listing of the Kinetoplastida CCCH proteins. The number of CCCH proteins with more then one CCCH motif is larger than previously estimated, due to the identification of non-conventional CCCH motifs. Experimental approaches are now necessary to examine the functions of the many unique CCCH proteins as well as the function of the putative Mex67 and the Leishmania 3'-5' exoribonuclease. |
| PMID: 20444260 [PubMed - as supplied by publisher] | |
| 8. | Med J Aust. 2010 Apr 5;192(7):413-6.Progressive meningoencephalitis in a Sudanese immigrant.Liu AP, Chou S, Gomes L, Ng T, Salisbury EL, Walker GL, Packham DR.Westmead Hospital, Sydney, NSW, Australia. peripatus2000@yahoo.com.au |
| PMID: 20367592 [PubMed - indexed for MEDLINE] | |
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| 9. | Phys Chem Chem Phys. 2010 Mar 7;12(9):2067-74. Epub 2010 Jan 8.Theoretical analysis of intermolecular interactions of selected residues of triosephosphate isomerase from Trypanosoma cruzi with its inhibitor 3-(2-benzothiazolylthio)-1-propanesulfonic acid.Chávez-Calvillo R, Costas M, Hernández-Trujillo J.Departamento de Física y Química Teórica, Facultad de Química, UNAM. Cd. Universitaria. México, DF 04510, México. AbstractThe interaction between selected amino acid residues of the homodimeric enzyme triosephosphate isomerase from Trypanosoma cruzi with the inhibitor 3-(2-benzothiazolylthio)-1-propanesulfonic acid (BTT) was investigated by means of high level quantum chemical methods. The amino acids phe75A, arg71A and tyr102B from the enzyme monomers A and B were selected using experimental X-ray structural data. The ab initio intermolecular energies for the association of the inhibitor with the individual amino acids were calculated in two forms, namely, with a supermolecular approach and using the symmetry adapted perturbation theory. The latter also provided the contributions to the interaction energies, which were interpreted in terms of the usual van der Waals forces. The electron density for the specific interactions between BTT and the amino acids and the charge redistribution due to complex formation were also analyzed. It was found that for phe75A and tyr102B the dispersion energy is the dominant contribution to the complex stabilization followed by the induction and electrostatic energies. In addition, whereas the face-edge complex of BTT with phe75A exhibits a C-H pi bond similar to that observed for the benzene dimer, the complex with arg71A shows an important charge redistribution on the amino acid in regions far removed from those where the intermolecular specific interactions occur. |
| PMID: 20165754 [PubMed - indexed for MEDLINE] | |
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| 10. | Exp Parasitol. 2010 Jun;125(2):100-5. Epub 2010 Jan 20.Trypanosoma evansi: pharmacological evidence of a nicotinic acetylcholine receptor.Portillo R, Bruges G, Delgado D, Betancourt M, Mijares A.Laboratorio de Fisiología de Parásitos, Centro de Biofísica y Bioquímica, Instituto Venezolano de Investigaciones Científicas, Apartado Postal 21827, Caracas 1020A, Venezuela. AbstractThe role of calcium and its relevance have been deeply revised with respect to trypanosomatids, as the mechanism by which calcium enters trypanosomes was, until now, not well understood. There is evidence supporting the presence of a nAChR in another member of the trypanosomatidae family, Trypanosoma cruzi, these receptors being one entry path to calcium ions. The aims of this work were to determine if there was a nicotinic acetylcholine receptor (nAChR) in Trypanosoma evansi, and to subsequently perform a partial pharmacological characterization of this receptor. After being loaded with FURA-2AM, individual cells of T. evansi, were exposed to cholinergic compounds, and the cells displayed a dose-dependent response to carbachol. This observation indicated that a cholinergic receptor may be present in T. evansi. Although a dose-dependent response to muscarine could not be demonstrated, nicotine could promote an incremental dose-dependent response. The relative potency of this specific agonist of nAChR is in agreement with previous reports. The estimated affinity values were a Kd1 value of 29.6+/-5.72 nM and a Kd2 value of 315.9+/-26.6 nM, which is similar to the Kd value reported for the alpha4 nicotinic receptor. The Hill coefficients were determined to be an n1 of 1.2+/-0.3 and an n2 of 4.2+/-1.3. Finally, our calculations indicated that there are about 1020 receptors in each T. evansi parasite, which is approximately 15-fold lower than the number reported in Torpedo californica electric cells. These results suggest the presence of a nAChR in T. evansi, which is able to bind nicotinic ligands and induce calcium signals. Copyright (c) 2010 Elsevier Inc. All rights reserved. |
| PMID: 20093112 [PubMed - indexed for MEDLINE] | |
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