Trypanosoma

.Cơ thể Trypanosoma nhỏ, dài khoảng 38-54 μ, chiều rộng 1,2 - 4,6 μ , kích thước thay đổitheo loài. ở giữa cơ thể lớn, 2 đầu nhỏ, có 1 roi ở phía trước, mỗi khi vận động cơ thể rất hoạt bát nhưng ít thay đổi vị trí. Hạch của tế bào hình bầu dục ở chính giữa cơ thể. Chiều dài của hạch lớn gần bằng chiều ngang cơ thể. Hạch nhỏ hình tròn ở gần điểm gốc của roi. Phần sau cơ thể có hạt gốc roi sinh ra roi chạy dài theo bề mặt cơ thể...

4p nhonnhipnp 13-06-2013 112 1   Download

Trypanosoma brucei is the cause of the diseases known as sleeping sickness in humans (T. brucei ssp. gambiense and ssp. rhodesiense) and ngana in domestic animals (T. brucei brucei) in Africa. Procyclic trypomastigotes, the tsetse vector stage, express a surface-bound trans-sialidase that transfers sialic acid to the glycosylphosphatidylinositol anchor of procyclin, a surface glycoprotein covering the parasite surface. Trans-sialidase is a unique enzyme expressed by a few trypanosomatids that allows them to scavenge sialic acid from sialylated compounds present in the infected host. ...

10p system191 01-06-2013 44 4   Download

This study reports the identification and characterization of the regulatory subunit, TbRSU, of protein kinase A of the parasitic protozoon Trypanosoma brucei. TbRSU is coded for by a single copy gene. The protein contains an unusually long N-terminal domain, the pseudosubstrate site involved in binding and inactivation of the catalytic subunit, and two C-terminally located, closely spaced cyclic nucleotide binding domains.

10p system191 01-06-2013 36 4   Download

In this article, we report the results of an analysis of the glycolytic enzyme enolase (2-phospho-D-glycerate hydro-lase) of Trypanosoma brucei. Enolase activity was detected in both bloodstream-form and procyclic insect-stage try-panosomes, although a 4.5-fold lower specific activity was found in the cultured procyclic homogenate. Subcellular localization analysis showed that the enzyme is only pre-sent in the cytosol.

9p tumor12 20-04-2013 28 3   Download

It has been shown previously in various organisms that the peroxin PEX14 is a component of a docking complex at the peroxisomalmembrane,where it is involved in the import of matrix proteins into the organelle after their synthesis in the cytosol and recognition by a receptor. Here we present a characterization of theTrypanosoma bruceihomologue of PEX14. It is shown that the protein is associated with gly-cosomes,the peroxisome-like organelles of trypanosomatids in which most glycolytic enzymes are compartmentalized....

9p fptmusic 16-04-2013 46 2   Download

We report here the first crystal structure of a stable isosteric analogue of 1,3-bisphospho-D-glyceric acid (1,3-BPGA) bound to the catalytic domain of Trypanosoma cruzi glycosomal glyceraldehyde-3-phosphate dehydrogenase (gGAPDH)in which the two phosphoryl moieties interact with Arg249. This complex possibly illustrates a step of the catalytic process by which Arg249 may induce compression of the product formed, allowing its expulsion fromthe active site.

13p fptmusic 12-04-2013 70 3   Download

Trypanosoma cruzi, the parasitic protozoan that causes Chagas disease, contains a major cysteine proteinase, cruzipain. This lysosomal enzyme bears an unusual C-terminal extension that contains a number of post-translational modifications, and most antibodies in natural and experimen-tal infections are directed against it. In this report we took advantage of UV-MALDI-TOF mass spectrometry in conjunction with peptide N-gly-cosidase F deglycosylation and high performance anion exchange chroma-tography analysis to address the structure of the N-linked oligosaccharides present in this domain. ...

13p fptmusic 11-04-2013 42 2   Download

The recombinant cysteine peptidases, cruzain from Trypanosoma cruziand CPB2.8DCTE fromLeishmania mexicana, are cathepsin L-like and characteristically endo-peptidases. In this study, we characterized the carboxydi-peptidase activities of these enzymes and compared them with those of human recombinant cathepsin B and cathep-sin L. The analysis used the internally quenched fluorescent peptide Abz-FRFK*-OH and some of its analogues, where Abz isortho-aminobenzoic acid and K* is (2,4-dinitrophe-nyl)-e-NH2-lysine. ...

8p dell39 03-04-2013 35 5   Download

An open reading frame with fatty acid desaturase similarity was identified in the genome ofTrypanosoma brucei.The 1224 bp sequence specifies a proteinof 408 amino acids with 59% and 58% similarity toMortierella alpinaandArabid-opsis thalianaD12 desaturase, respectively, and 51% with A. thalianax3 desaturases. The histidine tracks that com-pose the iron-binding active centers of the enzyme were more similar to those of thex3 desaturases.

8p dell39 03-04-2013 45 3   Download

Cyclic nucleotide specific phosphodiesterases (PDEs) are important components of all cAMP signalling networks. In humans, 11 different PDE families have been identified to date, all of which belong to the class I PDEs. Pharmaco-logically, theyhavebecome of great interest as targets for the development of drugs for a large variety of clinical condi-tions. PDEs in parasitic protozoa have not yet been exten-sively investigated, despite their potential as antiparasitic drug targets.

11p dell39 03-04-2013 40 4   Download

We have previously demonstrated that wild-typeTrypanosoma cruziepi-mastigotes lack arginine decarboxylase (ADC) enzymatic activity as well as its encoding gene. A foreign ADC has recently been expressed in T. cruzi after transformation with a recombinant plasmid containing the complete coding region of the oatADCgene.

10p dell39 27-03-2013 33 2   Download

A survey of the three kinetoplastid genome projects revealed the presence of three putative front-end desaturase genes inLeishmania major, one in Trypanosoma bruceiand two highly identical ones (98%) inT. cruzi. The encoded gene products were tentatively annotated as D8, D5 and D6 desaturases for L. major, and D6 desaturase for both trypanosomes.

10p dell39 27-03-2013 32 3   Download

Cyclic-nucleotide-specific phosphodiesterases (PDEs) are key players in the intracellular signaling pathways of the important human pathogen Trypano-soma cruzi. We report herein the identification of an unusual PDE from this protozoal organism. This enzyme, TcrPDEC, is a member of the class I PDEs, as determined from the presence of a characteristic signature sequence and from the conservation of a number of functionally important amino acid residues within its catalytic domain.

11p dell39 27-03-2013 41 2   Download

Cell exposure to hypo-osmolarity and alkalinity triggers a spectrum of responses including activation of phospholipases. Glycosylphosphatidyl-inositol-specific phospholipase C (GPI-PLC) is expressed in Trypanosoma brucei, a protozoan parasite that causes human African trypanosomia-sis.

17p inspiron33 26-03-2013 50 4   Download

Papain-like cysteine proteases of pathogenic protozoa play important roles in parasite growth, differentiation and host cell invasion. The main cysteine proteases of Trypanosoma cruzi(cruzipain) and of Trypanosoma brucei (brucipain) are validated targets for the development of new chemothera-pies.

11p galaxyss3 21-03-2013 55 4   Download

Triatoma infestans(Hemiptera: Reduviidae) is a hematophagous insect that transmits the protozoan parasite Trypanosoma cruzi, the etiological agent of Chagas’ disease. Its saliva contains trialysin, a protein that forms pores in membranes. Peptides based on the N-terminus of trialysin lyse cells and fold into a-helical amphipathic segments resembling antimicrobial peptides. Using a specific antiserum against trialysin, we show here that trialysin is synthesized as a precursor that is less active than the protein released after saliva secretion. ...

9p media19 06-03-2013 47 2   Download

6-Phosphogluconate dehydrogenase is a potential target for new drugs against African trypanosomiasis. Phosphorylated aldonic acids are strong inhibitors of 6-phosphogluconate dehydrogenase, and 4-phospho-d-erythro-nate (4PE) and 4-phospho-d-erythronohydroxamate are two of the stron-gest inhibitors of theTrypanosoma bruceienzyme.

10p media19 05-03-2013 35 3   Download

Enolase is a validated drug target inTrypanosoma brucei. To better charac-terize its properties and guide drug design efforts, we have determined six new crystal structures of the enzyme, in various ligation states and confor-mations, and have carried out complementary molecular dynamics simula-tions.

13p media19 04-03-2013 55 3   Download

African trypanosomes possess high levels of alanine aminotransferase (EC 2.6.1.2), although the function of their activity remains enigmatic, espe-cially in slender bloodstream forms where the metabolism of ketoacids does not occur. Therefore, the gene for alanine aminotransferase enzyme inTry-panosoma brucei(TbAAT) was characterized and its function assessed using a combination of RNA interference and gene knockout approaches.

13p vinaphone15 27-02-2013 55 3   Download

In trypanosomatids, the regulation of gene expression occurs mainly at the post-transcriptional level. Previous studies have revealed nontranslated mRNA in theTrypanosoma cruzicytoplasm. Previously, we have identified and cloned the TcDHH1 protein, a DEAD box RNA helicase. It has been reported that Dhh1 is involved in multiple RNA-related processes in vari-ous eukaryotes.

12p viettel02 19-02-2013 37 3   Download