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Dick CF, Rocco-Machado N, Dos-Santos ALA, Carvalho-Kelly LF, Alcantara CL, Cunha-E-Silva NL, Meyer-Fernandes JR, Vieyra A. An Iron Transporter Is Involved in Iron Homeostasis, Energy Metabolism, Oxidative Stress, and Metacyclogenesis in Trypanosoma cruzi. Front Cell Infect Microbiol 2022; 11:789401. [PMID: 35083166 PMCID: PMC8785980 DOI: 10.3389/fcimb.2021.789401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Accepted: 12/06/2021] [Indexed: 11/29/2022] Open
Abstract
The parasite Trypanosoma cruzi causes Chagas’ disease; both heme and ionic Fe are required for its optimal growth, differentiation, and invasion. Fe is an essential cofactor in many metabolic pathways. Fe is also harmful due to catalyzing the formation of reactive O2 species; for this reason, all living systems develop mechanisms to control the uptake, metabolism, and storage of Fe. However, there is limited information available on Fe uptake by T. cruzi. Here, we identified a putative 39-kDa Fe transporter in T. cruzi genome, TcIT, homologous to the Fe transporter in Leishmania amazonensis and Arabidopsis thaliana. Epimastigotes grown in Fe-depleted medium have increased TcIT transcription compared with controls grown in regular medium. Intracellular Fe concentration in cells maintained in Fe-depleted medium is lower than in controls, and there is a lower O2 consumption. Epimastigotes overexpressing TcIT, which was encountered in the parasite plasma membrane, have high intracellular Fe content, high O2 consumption—especially in phosphorylating conditions, high intracellular ATP, very high H2O2 production, and stimulated transition to trypomastigotes. The investigation of the mechanisms of Fe transport at the cellular and molecular levels will assist in elucidating Fe metabolism in T. cruzi and the involvement of its transport in the differentiation from epimastigotes to trypomastigotes, virulence, and maintenance/progression of the infection.
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Affiliation(s)
- Claudia F Dick
- Leopoldo de Meis Institute of Medical Biochemistry, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.,Carlos Chagas Filho Institute of Biophysics, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.,National Center of Structural Biology and Bioimaging (CENABIO), Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Nathália Rocco-Machado
- Leopoldo de Meis Institute of Medical Biochemistry, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.,National Center of Structural Biology and Bioimaging (CENABIO), Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - André L A Dos-Santos
- Leopoldo de Meis Institute of Medical Biochemistry, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.,National Center of Structural Biology and Bioimaging (CENABIO), Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Luiz F Carvalho-Kelly
- Leopoldo de Meis Institute of Medical Biochemistry, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.,National Center of Structural Biology and Bioimaging (CENABIO), Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Carolina L Alcantara
- Carlos Chagas Filho Institute of Biophysics, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.,National Center of Structural Biology and Bioimaging (CENABIO), Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Narcisa L Cunha-E-Silva
- Carlos Chagas Filho Institute of Biophysics, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.,National Center of Structural Biology and Bioimaging (CENABIO), Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - José R Meyer-Fernandes
- Leopoldo de Meis Institute of Medical Biochemistry, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.,National Center of Structural Biology and Bioimaging (CENABIO), Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Adalberto Vieyra
- Carlos Chagas Filho Institute of Biophysics, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.,National Center of Structural Biology and Bioimaging (CENABIO), Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.,Graduate Program in Translational Biomedicine/BIOTRANS, Unigranrio University, Duque de Caxias, Brazil
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2
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E-NTPDase (ecto-nucleoside triphosphate diphosphohydrolase) of Leishmania amazonensis inhibits macrophage activation. Microbes Infect 2015; 17:295-303. [DOI: 10.1016/j.micinf.2014.12.009] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Revised: 12/15/2014] [Accepted: 12/16/2014] [Indexed: 12/24/2022]
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3
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Extracellular nucleotide metabolism in Leishmania: influence of adenosine in the establishment of infection. Microbes Infect 2008; 10:850-7. [PMID: 18656412 DOI: 10.1016/j.micinf.2008.04.016] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2007] [Revised: 04/10/2008] [Accepted: 04/24/2008] [Indexed: 12/20/2022]
Abstract
Leishmaniasis is a parasitic disease with a variety of clinical forms, which are related to the Leishmania species involved. In the murine model, Leishmania amazonensis causes chronic non-healing lesions in Leishmania braziliensis- or Leishmania major-resistant mouse strains. In this study, we investigated the involvement of the pathway of extracellular nucleotide hydrolysis, with special focus on the role of extracellular adenosine, in the establishment of Leishmania infection. Our results show that the more virulent parasite--L. amazonensis--hydrolyzes higher amounts of ATP, ADP and AMP than the two other species, probably due to the higher expression of membrane NTPDase. Corroborating the idea that increased production of adenosine is important to lesion development and establishment of tissue parasitism, we observed that increased 5'-nucleotidase activity in L. braziliensis or addition of adenosine at the moment of infection with this parasite resulted in an increase in lesion size and parasitism as well as a delay in lesion healing. Furthermore, inhibition of adenosine receptor A2B led to decreased lesion size and parasitism. Thus, our results suggest that the conversion of ATP, a molecule with pro-inflammatory activity, into adenosine, which possesses immunomodulatory properties, may contribute to the establishment of infection by Leishmania.
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Salto ML, Kuhlenschmidt T, Kuhlenschmidt M, de Lederkremer RM, Docampo R. Phospholipid and glycolipid composition of acidocalcisomes of Trypanosoma cruzi. Mol Biochem Parasitol 2007; 158:120-30. [PMID: 18207579 DOI: 10.1016/j.molbiopara.2007.12.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2007] [Revised: 11/28/2007] [Accepted: 12/01/2007] [Indexed: 10/22/2022]
Abstract
Highly purified acidocalcisomes from Trypanosoma cruzi epimastigotes were obtained by differential centrifugation and iodixanol gradient ultracentrifugation. Lipid analysis of acidocalcisomes revealed the presence of low amounts of 3beta-hydroxysterols and predominance of phospholipids. Alkylacyl phosphatidylinositol (16:0/18:2), diacyl phosphatidylinositol (18:0/18:2), diacyl phosphatidylcholine (16:0/18:2; 16:1/18:2; 16:2/18:2; 18:1/18:2 and 18:2/18:2), and diacyl phosphatidylethanolamine (16:0/18:2 and 16:1/18:2) were the only phospholipids characterized by electrospray ionization-mass spectrometry (ESI-MS). Incubation of epimastigotes with [(3)H]-mannose and isolation of acidocalcisomes allowed the detection of a glycoinositolphospholipid (GIPL) in these organelles. The sugar content of the acidocalcisomal GIPL was similar to that of the GIPL present in a microsomal fraction but the amount of galactofuranose and inositol with respect to the other monosaccharides was lower, suggesting a different chemical structure. Taken together, these results indicate that acidocalcisomes of T. cruzi have a distinct lipid and carbohydrate composition.
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Affiliation(s)
- María Laura Salto
- Department of Pathobiology, University of Illinois at Urbana-Champaign, Urbana, IL 61802, United States
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5
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Abstract
Cell fractionation, a methodological strategy for obtaining purified organelle preparations, has been applied successfully to parasitic protozoa by a number of investigators. Here we present and discuss the work of several groups that have obtained highly purified subcellular fractions from trypanosomatids, Apicomplexa and trichomonads, and whose work have added substantially to our knowledge of the cell biology of these parasites.
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Affiliation(s)
- Wanderley de Souza
- Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, 21941-900, Brasil.
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6
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Cunha-e-Silva NL, Atella GC, Porto-Carreiro IA, Morgado-Diaz JA, Pereira MG, De Souza W. Isolation and characterization of a reservosome fraction from Trypanosoma cruzi. FEMS Microbiol Lett 2002; 214:7-12. [PMID: 12204365 DOI: 10.1111/j.1574-6968.2002.tb11317.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Reservosomes are acidic compartments present at the posterior region of epimastigote forms of Trypanosoma cruzi that store proteins and lipids. During metacyclogenesis, they consume their contents and disappear. Reservosomes are rich in cruzipain, the main proteolytic enzyme of this parasite. By centrifugation in a sucrose gradient, we have obtained a highly purified subcellular fraction containing reservosomes from 5-day-old Y strain epimastigotes. Transmission electron microscopy showed that the fraction contained well-preserved organelles. The protein profile of the organelle analyzed by SDS-PAGE depicted a wide range of protein bands, predominating those corresponding to a triplet of 60-51 kDa and a doublet of 25-23 kDa. Protease activity in substrate-containing gels, in the presence or absence of protease inhibitors, showed that cysteine proteinase is enriched and very active in the purified fraction. Enzymatic assays demonstrated the absence of pyrophosphatase, an acidocalcisome marker, and succinate cytochrome c reductase, a mitochondrial marker, although these enzymes were active in other regions of the purification sucrose gradient. Thin layer chromatographic neutral lipid analysis of purified reservosomes demonstrated that the organelle stores large amounts of ergosterol and esterified cholesterol. Phospholipid analysis indicated phosphatidylcholine and phosphatidylethanolamine as the major constituents of reservosome membranes.
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Affiliation(s)
- Narcisa L Cunha-e-Silva
- Lab. Ultraestrutura Celular Hertha Meyer, Inst. Biofísica Carlos Chagas Filho, UFRJ, CCS Bloco G, Rio de Janeiro 21949-900, Brazil.
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Taylor MC, Muhia DK, Baker DA, Mondragon A, Schaap PB, Kelly JM. Trypanosoma cruzi adenylyl cyclase is encoded by a complex multigene family. Mol Biochem Parasitol 1999; 104:205-17. [PMID: 10593176 DOI: 10.1016/s0166-6851(99)00154-1] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The parasitic protozoan Trypanosoma cruzi undergoes several differentiation events during its life cycle. Some of these transitions are thought to involve activation of adenylyl cyclase via the binding of peptide ligands to the cell surface. Here we describe the characterisation of the adenylyl cyclase gene family of T. cruzi. Two complete genes and one pseudogene have been sequenced. The protein products appear to have a large extracellular domain, a single transmembrane helix and a cytosolic catalytic domain. The adenylyl cyclase genes are present on at least six chromosomes and are scattered rather than clustered. They form a large polymorphic family in which the extracellular domain is particularly variable. An Escherichia coli adenylyl cyclase mutant could be complemented by expression of the catalytic domain of the T. cruzi enzyme. The recombinant protein had adenylyl cyclase activity in vitro, which was enhanced by increasing concentrations of divalent cations (Mn2+ > Mg2+). This constitutively active recombinant protein will be a useful tool for dissecting the catalytic mechanism of adenylyl cyclase.
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Affiliation(s)
- M C Taylor
- Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, UK.
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8
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L'Hostis C, Geindre M, Deshusses J. Active transport of L-proline in the protozoan parasite Trypanosoma brucei brucei. Biochem J 1993; 291 ( Pt 1):297-301. [PMID: 8471048 PMCID: PMC1132516 DOI: 10.1042/bj2910297] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The characteristics of L-proline transport in the procyclic form of Trypanosoma brucei were studied by using L-[14C]proline and a quick separation technique by centrifugation through an oil mixture. L-Proline uptake displayed typical Michaelis-Menten kinetics, with a Km of 19 microM and a maximum transport velocity of 17 nmol/min per 10(8) cells at 27 degrees C. The maximum concentration gradient factor obtained after 1 min of incubation was 270-fold in 0.02 mM proline. Cells permeabilized with 80 microM digitonin were still able to accumulate 14C label, but to a lower extent. The temperature-dependence of proline uptake gave an apparent activation energy of 74.9 kJ.mol-1. In competition studies with a 10-fold excess of structural analogues, L-alanine, L-cysteine and L-azetidine-2-carboxylate were found to inhibit L-proline uptake. Variation of pH or addition of the protonophore carbonyl cyanide m-chlorophenylhydrazone ('CCCP') did not affect proline transport, showing that it is not driven by a protonmotive force. The absence of Na+, with or without monensin, did not affect proline transport. The absence of K+ and the addition of the Na+,K(+)-ATPase inhibitor ouabain had no significant effect on proline uptake activity. The thiol-modifying reagent iodoacetate (10 mM) decreased proline uptake by half. KCN (1 mM) inhibited proline uptake to a lesser extent, and the degree of inhibition was proportional to the intracellular ATP concentration. Preliminary experiments on proline transport in plasma-membrane vesicles of the cells, using a filtration technique, showed an uptake of proline (0.67 nmol/mg of protein) by the vesicles, but only in the presence of intravesicular ATP. The results thus obtained suggest that the proline carrier system in T. brucei is ATP-driven and independent of Na+, K+ or H+ co-transport.
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Affiliation(s)
- C L'Hostis
- Department of Biochemistry, University of Geneva, Switzerland
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9
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al-Chalabi KA, Ziz LA, al-Khayat B. Presence and properties of cAMP phosphodiesterase from promastigote forms of Leishmania tropica and Leishmania donovani. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. B, COMPARATIVE BIOCHEMISTRY 1989; 93:789-92. [PMID: 2553330 DOI: 10.1016/0305-0491(89)90046-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
1. This paper reports the isolation and the partial purification of cAMP phosphodiesterase (EC 3.1.4.17) from the promastigote form of Leishmania tropica and a preliminary result from Leishmania donovani. 2. The activity of the fraction obtained from column chromatography was measured. 3. The effects of pH, temperature, time of incubation and various compounds on its activity in vitro were obtained. 4. Two peaks (I and II) exhibiting cyclic nucleotide phosphodiesterase activity were obtained. 5. Both activities were found to require the addition of Mg2+ ions for full effect. 6. The apparent Km values for the first and second peaks were 1.43 x 10(-3) M and 4.1 x 10(-3) M respectively. L. donovani shows only one peak of activity.
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Affiliation(s)
- K A al-Chalabi
- Department of Biology, College of Science, University of Mosul, Iraq
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10
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Urbina JA, Vivas J, Ramos H, Larralde G, Aguilar Z, Avilán L. Alteration of lipid order profile and permeability of plasma membranes from Trypanosoma cruzi epimastigotes grown in the presence of ketoconazole. Mol Biochem Parasitol 1988; 30:185-95. [PMID: 2845268 DOI: 10.1016/0166-6851(88)90111-9] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Highly purified preparations of plasma membranes from control and ketoconazole-treated (1 microM, 120 h) epimastigotes of Trypanosoma cruzi have been obtained by cell disruption using abrasion with glass beads, differential centrifugation and isopycnic centrifugation in continuous, self-generating Percoll gradients. The purity of the preparation was ascertained by the specific activity 125I bound to the membranes obtained from enzymatically radiolabeled epimastigotes and by the alpha-methyl-mannoside sensitive binding of 125I-concanavalin A. The membranes form closed vesicles of 0.2-0.4 micron in diameter which display Mg2+ ATPase and acid phosphatase activities, but are devoid of 5'-nucleotidase and succinate-cytochrome c oxidoreductase; these vesicles can be strongly agglutinated by concanavalin A. The lipid order profiles of membranes from control and treated cells were compared with that present in egg phosphatidylcholine/ergosterol liposomes (84:16, mol/mol) by electron spin resonance spectroscopy of doxylstearic acid probes with the nitroxide group bound to carbon 5, 10, 12 and 16 of the stearic acid chain. Membranes from treated epimastigotes have a lipid order profile which resembles that of control plasma membranes near the polar surface (positions 5 and 10) but there is an abrupt decrease of order at position 12 and from there to the center of bilayer is highly disordered, even more than in pure lipid membranes. Consistent with these results, the leakage of L-[14C]glucose from membrane vesicles of ketoconazole-treated cells is much faster than that observed in vesicles obtained from control cells. These results indicate a strong alteration of the plasma membrane physical and biological properties due to the incubation of the parasite with the drug; this alteration is consistent with the accumulation of methylated precursors of ergosterol, which affects both lipid-lipid and lipid-protein interactions in the membrane.
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Affiliation(s)
- J A Urbina
- Centro de Biologia Celular, Facultad de Ciencias, Universidad Central de Venezuela, Caracas
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11
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de Castro SL, Meirelles MDN, Oliveira MM. Trypanosoma cruzi: adrenergic modulation of cyclic AMP role in proliferation and differentiation of amastigotes in vitro. Exp Parasitol 1987; 64:368-75. [PMID: 2824234 DOI: 10.1016/0014-4894(87)90049-x] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Trypanosoma cruzi amastigotes, obtained from the supernatant of J774G-8 macrophage cultures infected with Y strain trypomastigotes, proliferated and differentiated into epimastigotes in Warren medium at 28-29 C. The basal level of adenosine 3':5'-monophosphate (cAMP) in recently harvested amastigotes was 0.12 pmole/10(7) cells, which could be increased in a dose-dependent manner to 0.62 pmole/10(7) cells with 1 mM of the adrenergic ligand isoproterenol plus 0.5 mM isobutyl methylxanthine. Isoproterenol inhibited [3H]thymidine incorporation into amastigote DNA, as well as the proliferation of amastigotes and newly transformed epimastigotes. Because dibutyryl cAMP had the same effect as isoproterenol on the cells, the experimental results suggest a role for cAMP, modulated by adrenergic ligands, in the control of proliferation and differentiation of amastigotes.
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Affiliation(s)
- S L de Castro
- Departamento de Ultraestrutura e Biologia Celular, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil
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12
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Abstract
Glycosomal (microbody)-enriched fractions prepared from epimastigote Trypanosoma cruzi were used as a partially purified source of phosphofructokinase. D-Fructose 6-phosphate showed sigmoidal kinetics at pH 7.0, but hyperbolic kinetics at pH 8.0. Various adenosine nucleotides were positive effectors; 5'-AMP was the most powerful. ATP showed hyperbolic kinetics under all conditions tested. Several described inhibitors and activators of mammalian phosphofructokinase were without significant effect on the trypanosomal enzyme; the absence of effect of D-fructose 2,6-bisphosphate is of particular note.
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Téllez-Iñón MT, Ulloa RM, Torruella M, Torres HN. Calmodulin and Ca2+-dependent cyclic AMP phosphodiesterase activity in Trypanosoma cruzi. Mol Biochem Parasitol 1985; 17:143-53. [PMID: 2999589 DOI: 10.1016/0166-6851(85)90013-1] [Citation(s) in RCA: 53] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Calmodulin has been purified from Trypanosoma cruzi epimastigote forms by ion-exchange chromatography, gel filtration and affinity chromatography on 2-chloro-10-(3-aminopropyl)phenotiazine-Sepharose. Upon sodium dodecyl sulfate-polyacrylamide gel electrophoresis, the factor showed a polypeptide band with an apparent molecular weight of 16 000. In addition, cyclic AMP phosphodiesterase activity from T. cruzi epimastigote forms was purified by ion-exchange chromatography and affinity chromatography on a brain calmodulin-Sepharose column. The enzyme was activated by homologous calmodulin as well as by bovine brain and Neurospora crassa calmodulins. The activation required micromolar concentrations of Ca2+ and it was blocked by EGTA and by some neuroleptic drugs such as chlorpromazine, fluphenazine and compound 48/80. Activations were observed at micromolar concentrations of cyclic AMP as substrate. In addition, T. cruzi calmodulin was also active in bringing about the stimulation of brain phosphodiesterase.
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Kuwahara T, White RA, Agosin M. A cytosolic FAD-containing enzyme catalyzing cytochrome c reduction in Trypanosoma cruzi. I. Purification and some properties. Arch Biochem Biophys 1985; 239:18-28. [PMID: 3923933 DOI: 10.1016/0003-9861(85)90807-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
A cytosolic flavoprotein enzyme for the protozoan, Trypanosoma cruzi, has been purified essentially to homogeneity by DEAE-cellulose and 2',5'-ADP-agarose column chromatography. The native enzyme has a molecular weight of 100,000 +/- 6,000, is composed of two identical subunits of molecular weight 52,000 +/- 1,000, and contains FAD in the ratio of 1 mol of FAD per mol of enzyme subunit. The enzyme is NADPH-dependent and is capable of reducing cytochrome c, ferricyanide, 2,6-dichloroindophenol, and menadione, but not adrenalin. It does not hydroxylate either sodium salicylate or sodium p-hydroxybenzoate, but N-methylaniline and N,N-dimethylaminobenzaldehyde-supported oxidation of NADPH has been demonstrated. Plots of initial velocity against NADPH concentration give hyperbolic curves with Km values of 6.289 X 10(-5) M. The enzyme is clearly different from the microsomal NADPH-cytochrome c reductase in its intracellular distribution, molecular weight, dimeric nature, presence of only FAD, and activity against secondary and tertiary aromatic amines.
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Oliveira MM, Antunes A, De Mello FG. Growth of Trypanosoma cruzi epimastigotes controlled by shifts in cyclic AMP mediated by adrenergic ligands. Mol Biochem Parasitol 1984; 11:283-92. [PMID: 6205265 DOI: 10.1016/0166-6851(84)90072-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Intracellular levels of cAMP in Trypanosoma cruzi epimastigotes were determined in the presence of the phosphodiesterase inhibitor 3-isobutyl-1-methylxanthine, and in the presence of the adrenergic ligand isoproterenol. An increase in the levels of cAMP was observed when those drugs were added. This effect was more pronounced when the cells were in the lag phase of growth. Phosphodiesterase inhibitors, catecholamines and dibutyryl cAMP inhibited proliferation of the organisms, as well as [3H]thymidine incorporation in in vitro experiments. These findings strongly suggest that cAMP plays a role in the control of growth of T. cruzi. The effects of adrenergic ligands in increasing cAMP levels and inhibiting growth could be reversed by beta-adrenergic antagonists, suggesting the presence of a receptor-mediated adenylate cyclase system in T. cruzi. Cholinergic ligands had no effect.
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Meirelles MN, De Souza W. Localization of a Mg2+-activated ATPase in the plasma membrane of Trypanosoma cruzi. THE JOURNAL OF PROTOZOOLOGY 1984; 31:135-40. [PMID: 6145795 DOI: 10.1111/j.1550-7408.1984.tb04302.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The Wachstein and Meisel incubation medium was used to detect ATPase activity in epimastigote, spheromastigote (amastigote), and bloodstream trypomastigote forms of Trypanosoma cruzi. Reaction product, indicative of enzyme activity, was associated with the plasma membrane covering the cell body and the flagellum of the parasite. No reaction product was found in the portion of the plasma membrane lining the flagellar pocket. The plasma membrane-associated ATPase activity was not inhibited by ouabain or oligomycin, was detected in incubation medium without K+, was inhibited by prolonged glutaraldehyde fixation, and its activity was diminished when Mg2+ was omitted from the incubation medium. The Ernst medium was used to detect Na+-K+-ATPase activity in T. cruzi. No reaction product indicative of the presence of this enzyme was detected. Reaction product indicative of 5'-nucleotidase was not detected in T. cruzi. Acid phosphatase activity was detected in lysosomes. Those results indicate that a Mg2+-activated ATPase is present in the plasma membrane of T. cruzi and that it can be used as an enzyme marker, provided that the mitochondrial and flagellar ATPases are inhibited, to assess the purity of plasma membrane fractions isolated from this parasite.
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Calderon RO, de Fabro SP. Trypanosoma cruzi: fusogenic ability of membranes from cultured epimastigotes in interaction with human syncytiotrophoblast. Exp Parasitol 1983; 56:169-79. [PMID: 6352320 DOI: 10.1016/0014-4894(83)90059-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Trypanosoma cruzi epimastigotes cultured in vitro were disrupted by successive freezing and thawing and subsequent sonication. The total homogenate was fractionated by differential centrifugation to obtain an enriched plasma membrane fraction. The proteins of subcellular parasite fractions were labeled with 131I and their binding to membrane fractions from human placenta syncytiotrophoblast was studied. Syncytiotrophoblast fractions enriched in plasma showed higher specific activity for binding an enriched T. cruzi plasma membrane fraction compared with other fractions of syncytiotrophoblast. The properties of this interaction were studied with digestive enzymes (trypsin and phospholipase A2). The results showed that both proteins and lipids could be involved in this interaction. The Ca2+ requirements for the membrane-membrane interaction are different for the two membranes studied. Also the enriched plasma membrane T. cruzi fraction had a higher capacity to induce fusion processes than the other subcellular fractions. The above results indicate that a preferential syncytiotrophoblast-T. cruzi interaction may occur between the two cell surfaces as compared to intracellular membranes and that the parasite surface is able to induce an instability process leading to membrane fusion. These results may have implications in regard to the mechanism of entry of the parasite into cells.
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Walter RD, Opperdoes FR. Subcellular distribution of adenylate cyclase, cyclic-AMP phosphodiesterase, protein kinases and phosphoprotein phosphatase in Trypanosoma brucei. Mol Biochem Parasitol 1982; 6:287-95. [PMID: 6294515 DOI: 10.1016/0166-6851(82)90061-5] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The subcellular distribution of adenylate cyclase, cyclic-AMP phosphodiesterase, protein kinases and phosphoprotein phosphatase in bloodstream forms of Trypanosoma brucei was determined by isopycnic sucrose-gradient centrifugation of post-large-granule extracts. Cyclic-AMP phosphodiesterase was almost entirely soluble whereas adenylate cyclase was membrane-bound. The latter enzyme appeared to be absent from the plasma-membrane fraction but copurified with acid phosphatase and acid phosphodiesterase indicating a possible association with the flagellar pocket. At least two protein kinase activities could be distinguished as based on their distribution profiles in gradients, their preference for exogenously added acceptor protein and their inhibition and stimulation by suramin and nucleoside, respectively. Suramin-sensitive protein kinase co-purified with the plasma-membrane marker alpha-D-glucosidase and a nucleoside-stimulated protein kinase behaved as a typical cell-sap enzyme. Phosphoprotein phosphatase activity was found to be mainly soluble but a small part seemed to be associated with plasma membranes.
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Gottlieb M, Dwyer DM. Leishmania donovani: surface membrane acid phosphatase activity of promastigotes. Exp Parasitol 1981; 52:117-28. [PMID: 7238722 DOI: 10.1016/0014-4894(81)90067-9] [Citation(s) in RCA: 95] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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Franco da Silveira J, Colli W. Chemical composition of the plasma membrane from epimastigote forms of Trypanosoma cruzi. BIOCHIMICA ET BIOPHYSICA ACTA 1981; 644:341-50. [PMID: 7020760 DOI: 10.1016/0005-2736(81)90392-8] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The chemical composition of two plasma membrane fractions from epimastigote forms of Trypanosoma cruzi is reported. Fraction M, a preparation obtained by conventional methods of cell fractionation is composed of 31% proteins, 34% lipids, 16% carbohydrates and 3% of the lipopeptidophosphoglycan. Phospholipids and sterols account for 7.5 and 9%, respectively, of the total mass. Phosphatidylethanolamine is the major phospholipid in fraction M, representing 45% of the total membrane phospholipids. The other fraction, fraction V (vesicles), was obtained by treatment of the cell with a vesiculating agent. This fraction contains 42% lipids, 20% carbohydrates, 13% proteins and 21% of the lipopeptidophosphoglycan. Phospholipids and sterols make up 17 and 8%, respectively, of the total mass of this fraction. Phosphatidylcholine and phosphatidylethanolamine are the main phospholipids found in fraction V. Phosphonolipids and sialic acid have not been detected in either membrane fraction. Sodium dodecyl sulfate polyacrylamide gel electrophoretic analysis show that the glycoproteins ABC and the lipopeptidophosphoglycan are 50- and 10-times more concentrated, respectively, in fractions V and M than in the whole cell homogenate. The high molar sterol/phospholipid ratio found in fraction M suggests that this fraction is less fluid than fraction V, perhaps reflecting a migration of certain membrane components in the presence of the vesiculating agent. Hence, fraction M is, probably, more representative of the epimastigote plasma membrane as a whole than fraction V.
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Gottlieb M, Dwyer DM. Protozoan parasite of humans: surface membrane with externally disposed acid phosphatase. Science 1981; 212:939-41. [PMID: 7233189 DOI: 10.1126/science.7233189] [Citation(s) in RCA: 92] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Plasma membranes isolated from the protozoan parasite Leishmania donovani were enriched in acid phosphatase (E.C. 3.1.3.2) activity. Cytochemically, the enzyme was distributed uniformly on the surface of intact cells and was localized on the external face of isolated membranes. Physical characteristics and orientation of the membrane-bound enzyme suggest that the organism is adapted for existence in hydrolytic environments.
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Piras MM, De Rodriguez OO, Piras R. Trypanosoma cruzi: antigenic composition of axonemes and flagellar membranes of epimastigotes cultured in vitro. Exp Parasitol 1981; 51:59-73. [PMID: 6161837 DOI: 10.1016/0014-4894(81)90042-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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Rovis L, Baekkeskov S. Sub-cellular fractionation of Trypanosoma brucei. Isolation and characterization of plasma membranes. Parasitology 1980; 80:507-24. [PMID: 6248830 DOI: 10.1017/s0031182000000974] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
A procedure is described for the isolation of sub-cellular fractions from bloodstream forms of Trypanosoma brucei. The method leaves intact most of the nuclei, mitochondria and microbodies. All the fractions have been chemically characterized and tested for 10 enzymatic markers. About 5% of total cell protein was isolated as a microsomal fraction containing mostly plasma membranes and endoplasmic reticulum vesicles. Plasma membranes were purified by high-speed centrifugation on magnesium-containing Dextran, and on linear sucrose-density gradients. The yield of membranes was approximately 0.3% of the total cell protein. The purified material had a sucrose density of 1.14 g/cm3 and consisted of smooth vesicles. Specific activity of the membrane markers Na+, K+, ouabain-sensitive ATPase and adenylate cyclase were 26- and 20-fold higher, respectively, than in total cells. Neither DNA nor RNA was detected. The sum of the cholesterol and phospholipid content was 0.99 mg/mg protein. The cholesterol/phospholipid molar ratio was 1:2.
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da Silveira JF, Abrahamsohn PA, Colli W. Plasma membrane vesicles isolated from epimastigote forms of Trypanosoma cruzi. BIOCHIMICA ET BIOPHYSICA ACTA 1979; 550:222-32. [PMID: 365244 DOI: 10.1016/0005-2736(79)90209-8] [Citation(s) in RCA: 40] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Membrane vesicles can be obtained from epimastigote forms of Trypansoma cruzi by incubating cells with either cross-linking reagents or acid pH. Acetate, phtalate or citrate, at pH 4.0, but not at higher pH values, were able to induce plasma membrane vesiculation. Vesicles have been purified by sucrose density centrifugation and their membrane origin was demonstrated by the following criteria: (a) Vesicles are 5--10 times richer in protein-bound iodine when they are prepared from cells previously labeled with 131I by the lactoperoxidase catalyzed reaction. (b) Electron microscopy of vesiculating cells shows physical continuity between cell plasma membrane and vesicle membrane. (c) Antibodies prepared against purified vesicles are able to agglutinate epimastigote forms of T. cruzi with sera dilutions up to 1 : 256 to 1 : 512. (d) Freeze-fracture studies of the purified vesicles have shown images of faces P and E compatible with known images of the intact cell plasma membrane. Typical preparations of acetate vesicles present the following characteristics: total carbohydrate : protein=1.5--2.0; orcinol : protein-0.07 and absence of diphenylamine reaction. Vesicles contain 0.2--0.5% and 0.3--1.0% of the total homogenate protein and carbohydrate, respectively. The presence of 10 major protein bands and 30--50-fold enrichment of the four sugar-containing macromolecules present in epimastigote forms of T. cruzi have been demonstrated in these preparations.
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