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Alotaibi A, Ebiloma GU, Williams R, Alenezi S, Donachie AM, Guillaume S, Igoli JO, Fearnley J, de Koning HP, Watson DG. European propolis is highly active against trypanosomatids including Crithidia fasciculata. Sci Rep 2019; 9:11364. [PMID: 31388043 PMCID: PMC6684629 DOI: 10.1038/s41598-019-47840-y] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Accepted: 07/25/2019] [Indexed: 11/30/2022] Open
Abstract
Extracts of 35 samples of European propolis were tested against wild type and resistant strains of the protozoal pathogens Trypanosoma brucei, Trypanosoma congolense and Leishmania mexicana. The extracts were also tested against Crithidia fasciculata a close relative of Crithidia mellificae, a parasite of bees. Crithidia, Trypanosoma and Leishmania are all members of the order Kinetoplastida. High levels of activity were obtained for all the samples with the levels of activity varying across the sample set. The highest levels of activity were found against L. mexicana. The propolis samples were profiled by using liquid chromatography with high resolution mass spectrometry (LC-MS) and principal components analysis (PCA) of the data obtained indicated there was a wide variation in the composition of the propolis samples. Orthogonal partial least squares (OPLS) associated a butyrate ester of pinobanksin with high activity against T. brucei whereas in the case of T. congolense high activity was associated with methyl ethers of chrysin and pinobanksin. In the case of C. fasciculata highest activity was associated with methyl ethers of galangin and pinobanksin. OPLS modelling of the activities against L. mexicana using the mass spectrometry produced a less successful model suggesting a wider range of active components.
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Affiliation(s)
- Abdullah Alotaibi
- University of Strathclyde, Strathclyde Institute of Pharmacy and Biomedical Science, 161 Cathedral Street, Glasgow, G4 0RE, UK
| | - Godwin U Ebiloma
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8TA, UK
| | - Roderick Williams
- IBEHR, School of Health and Life Science, University of the West of Scotland, High Street, Paisley, PA1 2BE, UK
| | - Samya Alenezi
- University of Strathclyde, Strathclyde Institute of Pharmacy and Biomedical Science, 161 Cathedral Street, Glasgow, G4 0RE, UK
| | - Anne-Marie Donachie
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8TA, UK
| | - Selome Guillaume
- IBEHR, School of Health and Life Science, University of the West of Scotland, High Street, Paisley, PA1 2BE, UK
| | - John O Igoli
- University of Strathclyde, Strathclyde Institute of Pharmacy and Biomedical Science, 161 Cathedral Street, Glasgow, G4 0RE, UK
- Department of Chemistry, University of Agriculture, PMB 2373, Makurdi, Nigeria
| | | | - Harry P de Koning
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8TA, UK
| | - David G Watson
- University of Strathclyde, Strathclyde Institute of Pharmacy and Biomedical Science, 161 Cathedral Street, Glasgow, G4 0RE, UK.
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Rojas R, Segovia C, Trombert AN, Santander J, Manque P. The effect of tunicamycin on the glucose uptake, growth, and cellular adhesion in the protozoan parasite Crithidia fasciculata. Curr Microbiol 2014; 69:541-8. [PMID: 24894907 DOI: 10.1007/s00284-014-0620-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2014] [Accepted: 04/08/2014] [Indexed: 01/17/2023]
Abstract
Crithidia fasciculata represents a very interesting model organism to study biochemical, cellular, and genetic processes unique to members of the family of the Trypanosomatidae. Thus, C. fasciculata parasitizes several species of insects and has been widely used to test new therapeutic strategies against parasitic infections. By using tunicamycin, a potent inhibitor of glycosylation in asparaginyl residues of glycoproteins (N-glycosylation), we demonstrate that N-glycosylation in C. fasciculata cells is involved in modulating glucose uptake, dramatically impacting growth, and cell adhesion. C. fasciculata treated with tunicamycin was severely affected in their ability to replicate and to adhere to polystyrene substrates and losing their ability to aggregate into small and large groups. Moreover, under tunicamycin treatment, the parasites were considerably shorter and rounder and displayed alterations in cytoplasmic vesicles formation. Furthermore, glucose uptake was significantly impaired in a tunicamycin dose-dependent manner; however, no cytotoxic effect was observed. Interestingly, this effect was reversible. Thus, when tunicamycin was removed from the culture media, the parasites recovered its growth rate, cell adhesion properties, and glucose uptake. Collectively, these results suggest that changes in the tunicamycin-dependent glycosylation levels can influence glucose uptake, cell growth, and adhesion in the protozoan parasite C. fasciculata.
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Affiliation(s)
- Robert Rojas
- Nucleus for Microbiology and Immunity, Center for Genomics and Bioinformatics, Faculty of Sciences, Universidad Mayor, Campus Huechuraba, Camino La Pirámide 5750, Huechuraba, Santiago, Chile,
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Fernández MM, Malchiodi EL, Algranati ID. Differential effects of paromomycin on ribosomes of Leishmania mexicana and mammalian cells. Antimicrob Agents Chemother 2011; 55:86-93. [PMID: 20956601 PMCID: PMC3019668 DOI: 10.1128/aac.00506-10] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2010] [Revised: 06/16/2010] [Accepted: 10/10/2010] [Indexed: 11/20/2022] Open
Abstract
Paromomycin, an aminoglycoside antibiotic having low mammalian cell toxicity, is one of the drugs currently used in the chemotherapy of cutaneous and visceral leishmaniasis. In order to understand the mode of action of this antibiotic at the molecular level, we have investigated the effects of paromomycin on protein synthesis in Leishmania and its mammalian hosts. We were able to demonstrate that in vivo protein synthesis in the promastigote stage of the parasite and its proliferation rate are markedly inhibited by paromomycin while being only slightly affected by other aminoglycoside antibiotics, such as streptomycin and neomycin B. Furthermore, both in vitro polypeptide synthesis induced by poly(U) as mRNA and accuracy of translation are significantly decreased by paromomycin in cell-free systems containing ribosomal particles of Leishmania promastigotes. Conversely, when ribosomes from mammalian cells are used instead of the protozoan particles, polyphenylalanine synthesis is only barely reduced by the antibiotic and the translation misreading remains almost unaltered. Surface plasmon resonance analysis of the interaction between paromomycin and protozoan or mammalian cell ribosomal RNAs shows a strong binding of antibiotic to the parasite ribosomal decoding site and practically no interaction with the mammalian cell counterpart. Our results indicating differential effects of paromomycin on the translation processes of the Leishmania parasite and its mammalian hosts can explain the therapeutic efficiency of this antibiotic as an antileishmaniasis agent.
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Affiliation(s)
- Marisa M. Fernández
- Cátedra de Inmunología and Instituto de Estudios de la Inmunidad Humoral (IDEHU), CONICET-UBA, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, 1113 Buenos Aires, Fundación Instituto Leloir, Patricias Argentinas 435, 1405 Buenos Aires, Argentina
| | - Emilio L. Malchiodi
- Cátedra de Inmunología and Instituto de Estudios de la Inmunidad Humoral (IDEHU), CONICET-UBA, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, 1113 Buenos Aires, Fundación Instituto Leloir, Patricias Argentinas 435, 1405 Buenos Aires, Argentina
| | - Israel D. Algranati
- Cátedra de Inmunología and Instituto de Estudios de la Inmunidad Humoral (IDEHU), CONICET-UBA, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, 1113 Buenos Aires, Fundación Instituto Leloir, Patricias Argentinas 435, 1405 Buenos Aires, Argentina
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Podesta D, Fernandez Villamil SH, Stoppani AO. [Inhibitory action of Fenton systems on topoisomerase I from Trypanosoma cruzi and Crithidia fasciculata]]. Rev Argent Microbiol 2003; 35:80-5. [PMID: 12920988] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/04/2023] Open
Abstract
Fenton systems (H2O2/Fe(II) or H2O2/Cu(II)) inhibited Trypanosoma cruzi and Crithidia fasciculata topoisomerase I activity. About 61-71% inactivation was produced by 25 mM Fe(II) or Cu(II) with 3 mM H2O2. Thiol compounds and free radicals scavengers prevented the Fenton systems effects, depending on the topoisomerase assayed. With the T. cruzi enzyme, reduced glutathione, DL-dithiothreitol, cysteine and N-acetyl-L-cysteine entirely prevented the effect of the H2O2/Fe(II) system, mannitol protected 37%, whereas histidine and ethanol were ineffective. With C. fasciculata topoisomerase, reduced glutathione, DL-dithiothreitol and N-acetyl-L-cysteine protected 100%, cysteine, histidine and mannitol protected 28, 34 and 48% respectively, whereas ethanol was ineffective. With the H2O2/Cu(II) system and T. cruzi topoisomerase, DL-dithiothreitol and histidine protected 100% and 60%, respectively but the other assayed protectors were less effective. Similar results were obtained with the C. fasciculata enzyme. Topoisomerase inactivation by H2O2/Fe(II) or H2O2/Cu(II) systems was irreversible since they were not reverted by the more effective enzyme protectors. It is suggested that topoisomerases could act either as scavengers of "reactive oxygen species" (ROS) generated by Fenton systems or bind the corresponding metal ions, whose redox cycling would generate reactive oxygen species "in situ".
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Affiliation(s)
- D Podesta
- Centro de Investigaciones Bioenergéticas (CONICET), Facultad de Medicina, Universidad de Buenos Aires, Paraguay 2155, 1121 Buenos Aires, Argentina
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Abstract
Trypanosomatid parasites containing a metabolically unstable ornithine decarboxylase (ODC) are naturally resistant to high levels of alpha-difluoromethylornithine (DFMO) because this ODC inhibitor, though causing a drastic reduction of intracellular putrescine, elicits only a moderate decrease of the spermidine endogenous pool. In this study we have used a combination of DFMO with cyclohexylamine (CHA; bis-cyclohexylammonium sulfate), an inhibitor of spermidine synthase, to reach a more complete depletion of spermidine. Under these conditions we have observed the arrest of proliferation not only in trypanosomatids with stable ODC but also in parasites with an enzyme of high turnover rate. In all cases the reinitiation of proliferation occurred only after the addition of exogenous spermidine, and neither putrescine nor spermine were able to induce the same effect.
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Affiliation(s)
- N S González
- Instituto de Investigaciones Bioquímicas Fundación Campomar, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires and CONICET, A. Machado 151, 1405, Buenos Aires, Argentina
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Biscardi AM, Lopez LM, de Pahn EM, Pellegrino de Iraldi A, Stoppani AO. Effect of dyskinetoplastic agents on ultrastructure and oxidative phosphorylation in Crithidia fasciculata. BIOCELL 2001; 25:43-51. [PMID: 11387876] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/20/2023]
Abstract
Ethidium bromide (EB) is an intercalating agent which binds specifically to the kinetoplast (mitochondrial) DNA (kDNA) of trypanosomatids. Accordingly, EB inhibits DNA replication, thus inducing dyskinetoplasty. Since in eukariotic organisms mitochondrial DNA encodes the genetic information for cytochromes b, aa3 and F0F1 ATPase, it seemed of interest to establish whether a similar effect occurs in Crithidia fasciculata, a trypanosomatid used for assay of potential trypanocidal drugs. Culturing of C. fasciculata in the presence of EB inhibited growth and induced dyskinetoplasty, as confirmed by electron microscopy. The kinetoplast of EB-cultured crithidia lost its characteristic arc shape, it was misplaced in the cell cytoplasm its matrix structure and membrane differentiation were specifically modified. Dyskinetoplasty decreased crithidia respiration and oxidative phosphorylation, as indicated by the lower ATP level, ATP/ADP ratio and adenylate energy charge. The interference of EB with kinetoplastic constituents synthesis was confirmed by the lack of action of EB on crithidia in the stationary phase of growth, that ruled out direct inhibition of oxidative phosphorylation enzymes. The lipophilic o-naphthoquinone beta-lapachone produced structural alterations in kinetoplast membranes, that correlated with inhibition of oxidative phosphorylation. These latter effects involved free radicals since they were prevented by free radical scavengers.
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Affiliation(s)
- A M Biscardi
- Bioenergetics Research Centre, School of Medicine, University of Buenos Aires, Argentina
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Carrillo C, Cejas S, Cortés M, Ceriani C, Huber A, González NS, Algranati ID. Sensitivity of trypanosomatid protozoa to DFMO and metabolic turnover of ornithine decarboxylase. Biochem Biophys Res Commun 2000; 279:663-8. [PMID: 11118342 DOI: 10.1006/bbrc.2000.3996] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
alpha-Difluoromethylornithine (DFMO), the specific and irreversible inhibitor of ornithine decarboxylase (ODC), was able to induce the arrest of proliferation in Leishmania mexicana and ODC-transformed Trypanosoma cruzi cultures grown in a semi-defined medium essentially free of polyamines. Conversely, Crithidia fasciculata and Phytomonas 274 were not affected by the inhibitor. The drug-resistance of Crithidia and Phytomonas was neither caused by an impairment of DFMO uptake nor by a decrease of the enzyme affinity for the inhibitor. We were also able to rule out the possibility of ODC overexpression in the drug-tolerant parasites. The measurements of ODC metabolic turnover indicated that the enzymes from Crithidia and Phytomonas have a short half-life of 20-40 min, while ODC from Leishmania and transgenic Trypanosoma cruzi are rather stable with a half-life longer than 6 hours. Analyses of polyamine internal pools under different growth conditions have shown that DFMO was able to markedly decrease the levels of putrescine and spermidine in all parasites, but the depletion of spermidine was higher in trypanosomatids containing an ODC with slow turnover. Our results suggest that in these parasites cultivated in the presence of the drug, spermidine might decrease below critical levels needed to maintain trypanothione concentrations or other conditions essential for normal proliferation.
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Affiliation(s)
- C Carrillo
- Instituto de Investigaciones Bioquímicas "Fundación Campomar,", Facultad de Ciencias Exactas y Naturales, A. Machado 151, Buenos Aires, 1405, Argentina
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Chan C, Yin H, Garforth J, McKie JH, Jaouhari R, Speers P, Douglas KT, Rock PJ, Yardley V, Croft SL, Fairlamb AH. Phenothiazine inhibitors of trypanothione reductase as potential antitrypanosomal and antileishmanial drugs. J Med Chem 1998; 41:148-56. [PMID: 9457238 DOI: 10.1021/jm960814j] [Citation(s) in RCA: 110] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Given the role of trypanothione in the redox defenses of pathogenic trypanosomal and leishmanial parasites, in contrast to glutathione for their mammalian hosts, selective inhibitors of trypanothione reductase are potential drug leads against trypanosomiasis and leishmaniasis. In the present study, the rational drug design approach was used to discover tricyclic neuroleptic molecular frameworks as lead structures for the development of inhibitors, selective for trypanothione reductase over host glutathione reductase. From a homology-modeled structure for trypanothione reductase, replaced in the later stages of the study by the X-ray coordinates for the enzyme from Crithidia fasciculata, a series of inhibitors based on phenothiazine was designed. These were shown to be reversible inhibitors of trypanothione reductase from Trypanosoma cruzi, linearly competitive with trypanothione as substrate and noncompetitive with NADPH, consistent with ping-pong bi bi kinetics. Analogues, synthesized to define structure-activity relationships for the active site, included N-acylpromazines, 2-substituted phenothiazines, and trisubstituted promazines. Analysis of Ki and I50 data, on the basis of calculated log P and molar refractivity values, provided evidence of a specially favored fit of small 2-substituents (especially 2-chloro and 2-trifluoromethyl), with a remote hydrophobic patch on the enzyme accessible for larger, hydrophobic 2-substituents. There was also evidence of an additional hydrophobic enzymic region available to suitable N-substituents of the promazine nucleus. Ki data also indicated that the phenothiazine nucleus can adopt more than one inhibitory orientation in its binding site. Selected compounds were tested for in vitro activity against Trypanosoma brucei, T. cruzi, and Leishmania donovani, with selective activities in the micromolar range being determined for a number of them.
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Affiliation(s)
- C Chan
- Department of Pharmacy, University of Manchester, U.K
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Calonge MM, Bayoumi AE, Cubría JC, Balaña-Fouce R, Ordóñez D. Effects of cationic diamidines on polyamine metabolism in the trypanosomatid Crithidia fasciculata. Life Sci 1996; 59:PL191-7. [PMID: 8809218 DOI: 10.1016/0024-3205(96)00411-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The effect of a series of five recently synthesized cationic diamidines on cell proliferation and polyamine metabolism was studied on cultures of the model Trypanosomatid Crithidia fasciculata. Compounds displaying two arylic moieties (CGP039937A and CGP040215A) were ten fold more cytostatic than those displaying only one arylic residue (CGP033829A, CGP035753A and CGP036958A). The depletion of intracellular polyamine, putrescine and spermidine, pools and the effect of these compounds on S-adenosylmethionine decarboxylase and putrescine uptake suggest the requirement of two arylic groups in their chemical structure to obtain measurable effects on both polyamine metabolism and cell growth.
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Affiliation(s)
- M M Calonge
- Departamento de Fisiología, Farmacología y Toxicología, Universidad de León, Spain
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Biscardi AM, Fernandez Villamil SH, Stoppani AO. [Inhibition of oxidative phosphorylation in Crithidia fasciculata and Trypanosoma cruzi by lipophilic o-quinones and nifurtimox]. Rev Argent Microbiol 1994; 26:72-86. [PMID: 7938505] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
ATP and ADP levels were determined in Crithidia fasciculata and Trypanosoma cruzi. The nucleotide levels in crithidia or epimastigotes at the stationary phase of growth were, in nmol/10(8) cells, 15-40, and 3-7, for ATP and ADP, respectively. Incubation with the lipophilic o-naphthoquinones CG 8-935, CG 9-442 and CG 10-248 or the anti-chagasic nitrofuran nifurtimox, significantly decreased ATP level, with non-significant variations of the ADP level. The kinetics of ATP variation showed an initial 1-2 h lag and the diminution of the ATP level reached maximum value after 4-6 h incubation. Addition of L-glutamate or D-glucose as energy sources produced 2- or 3-fold increase of ATP level, after incubation the protozoa for 4-6 h with the corresponding substrates. Quinones and nifurtimox strongly depressed D-glucose or L-glutamate effects. Buthionine sulfoximine an inhibitor of glutathione biosynthesis, enhanced the effect of nifurtimox on ATP level in Crithidia fasciculata. It is concluded that by inhibiting ATP synthesis, either directly or-through oxygen radicals, the assayed drugs produced their cytotoxic action.
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Affiliation(s)
- A M Biscardi
- Centro de Investigaciones Bioenergéticas, Facultad de Medicina, Universidad de Buenos Aires, Argentina
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Rilo MC, Stoppani AO. Effect of polyamines on mitochondrial F-ATPase from Crithidia fasciculata and Trypanosoma cruzi. Biochem Mol Biol Int 1993; 29:131-9. [PMID: 8490559] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
ATP hydrolysis by Crithidia fasciculata mitochondrial ATPase was studied through the use of submitochondrial particles and the soluble enzyme. (a) ATP hydrolysis by these preparations was inhibited by spermine but not by spermidine or putrescine. (b) The ATPase activity inhibited by spermine was partially recovered when excess Mg2+ was added to the reaction mixture. (c) When polyamines were present throughout the preparation of the mitochondrial membranes, the membrane-bound ATPase was irreversibly inactivated. The polyamine effect decreased in the order spermine > putrescine > spermidine. (d) The spermidine or putrescine pre-treated membranes oxidized succinate at a faster rate than the control ones. (e) Trypanosoma cruzi F-ATPase was inhibited by polyamines in the same manner as the C. fasciculata enzyme.
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Affiliation(s)
- M C Rilo
- Centro de Investigaciones Bioenergéticas, Facultad de Medicina (UBA), Argentina
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Abstract
Putrescine uptake in Trypanosoma cruzi epimastigotes is 10 to 50-fold higher than in Leishmania mexicana or Crithidia fasciculata. Polyamine transport in all these trypanosomatids is an energy-dependent process strongly inhibited by the presence of 2,4-dinitrophenol or KCN. Putrescine uptake in T. cruzi and L. mexicana was markedly decreased by the proton ionophore carbonylcyanide m-chlorophenylhydrazone but it was not affected by ouabain, a Na(+)-K+ pump inhibitor. The depletion of intracellular polyamines by treatment of parasite cultures with alpha-difluoromethylornithine elicited a marked induction of putrescine uptake in L. mexicana and C. fasciculata by increasing considerably the Vmax of this process. Conversely, the uptake of putrescine in T. cruzi was essentially unchanged by the same treatment. The differential regulation of putrescine transport in T. cruzi might be related to some distinctive features of polyamine metabolism in this parasite.
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Affiliation(s)
- N S González
- Instituto de Investigaciones Bioquímicas Fundación Campomar, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Argentina
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Ray DS, Hines JC, Anderson M. Kinetoplast-associated DNA topoisomerase in Crithidia fasciculata: crosslinking of mitochondrial topoisomerase II to both minicircles and maxicircles in cells treated with the topoisomerase inhibitor VP16. Nucleic Acids Res 1992; 20:3353-6. [PMID: 1321413 PMCID: PMC312488 DOI: 10.1093/nar/20.13.3353] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The mitochondrial DNA of the trypanosomatid Crithidia fasciculata consists of thousands of copies of a 2.5 kb minicircle and a small number of 37kb maxicircles catenated into a single enormous network. Treatment of C. fasciculata with the type II DNA topoisomerase inhibitor VP16 produces cleavable complexes of a type II DNA topiosomerase with both minicircles and maxicircles. A combined Southern and Western blot analysis of the cleaved DNA species released from the network by SDS treatment has identified topollmt, the kinetoplast-associated topisomerase, in covalent complexes with linear forms of minicircle and maxicircle DNAs. These results directly implicate topollmt in the topological reactions required for the duplication of the kinetoplast network.
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Affiliation(s)
- D S Ray
- Molecular Biology Institute, UCLA 90024
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Molina Portela MP, de Pahn EM, Galeffi C, Stoppani AO. [Effect of lipophilic ortho-naphthoquinones on the growth of and production of peroxides by Leptomonas seymouri and Crithidia fasciculata]. Rev Argent Microbiol 1991; 23:1-14. [PMID: 1667695] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The lipophilic o-naphthoquinones CG 8-935, CG 9-442, CG 10-248 and mansonones A, C, E and F inhibit growth of the trypanosomatids Leptomonas seymouri (LS) and Crithidia fasciculata (CF). The most active mansonones were E and F (I50, 0.1-0.4 microM with LS; 0.3-1.2 microM with CF) with cytotoxic activities equal to or higher than quinones CG, as reported previously. Incubation of LS or CF with the CG-quinones and mansonones E and F caused the release of H2O2 and O2-. from the whole cells to the suspending medium, as detected by the microperoxidase and adrenochrome assays, respectively. Lower O2-. and H2O2 production values were obtained with perezone and primine, two p-benzoquinones used as controls. Quinones effect on O2-. and H2O2 production was closely related to their concentration and with mansonones E and F, O2-. production was 4-5-fold higher than H2O2 production. Smaller differences were observed with the CG-quinones. Peroxide production in the assayed organisms was the result of quinone redox-cycling, which involved an anaerobic, reductive phase producing quinols, and an aerobic phase (II), in which quinol oxidation and peroxide production (O2-., H2O2) occurred. With mansonones E and F, and quinone CG, phase II rate was faster than or similar to phase I rate, but with mansonones A and C, the quinols oxidation rate was 8-10-fold slower than the quinones reduction rate. These differences fit in well with a) the quinol oxidation rates, measured in vitro; b) O2-. production by quinols oxidation and c) quinols capability for producing lucigenin chemiluminescence. These results support the assumption that oxyradicals play a relevant role in o-naphthoquinones cytotoxic action, despite the presence of catalase and other protective enzymes in CF and LS. Other effects are not, however, ruled out. CF and LS sensitivity towards the assayed o-quinones was similar or higher than that of Trypanosoma cruzi, thus allowing the use of those organisms for preliminary screening of antichagasic drugs.
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Affiliation(s)
- M P Molina Portela
- Centro de Investigaciones Bioenergéticas, Facultad de Medicina, Universidad de Buenos Aires, Argentina
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