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Euan-Canto A, Torres-Romero JC, Alvarez-Sánchez ME, Arana-Argáez VE, Acosta-Viana K, Ceballos-Góngora E, Vázquez-Carrillo L, Alvarez-Sánchez L. Activation of murine macrophages by membrane proteins from Tritrichomonas foetus grown on iron- and calcium-rich conditions. Parasite Immunol 2024; 46:e13020. [PMID: 38275198 DOI: 10.1111/pim.13020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Revised: 12/08/2023] [Accepted: 12/11/2023] [Indexed: 01/27/2024]
Abstract
Tritrichomonas foetus is a protozoan parasite that causes a venereal disease in cattle limiting reproduction by abortions and sterility. The immune response against this parasite is poorly understood. Since the iron and calcium ions are important regulators of the microenvironment of the urogenital tract in cattle, we decided to evaluate the role of these divalent cations on the antigenicity of membrane proteins of T. foetus on macrophage activation as one of the first inflammatory responses towards this pathogen. Colorimetric methods and ELISA were used to detect the nitric oxide and oxygen peroxide production and expression of cytokines in culture supernatant from macrophage incubated with membrane proteins from T. foetus cultured in iron- and calcium-rich conditions. qRT-PCR assays were used to evaluate the transcript expression of genes involved in the inflammatory response on the macrophages. The membrane proteins used for in vitro stimulation caused the up-regulation of the iNOS and NOX-2 genes as well as the generation of NO and H2 O2 in murine macrophages on a dependent way of the metal concentrations. Additionally, after stimulation, macrophages showed a considerable rise in pro-inflammatory cytokines and a downregulation of anti-inflammatory cytokines, as well as up-regulation in the transcription of the TLR4 and MyD88 genes. These data suggest that membrane proteins of T. foetus induced by iron and calcium can activate an inflammatory specific macrophage response via TLR4/MyD88 signalling pathway.
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Affiliation(s)
- Antonio Euan-Canto
- Laboratorio de Bioquímica y Genética Molecular, Facultad de Química, Universidad Autónoma de Yucatán, Mérida, Yucatán, Mexico
- Laboratorio de Farmacología, Facultad de Química, Universidad Autónoma de Yucatán, Mérida, Yucatán, Mexico
| | - Julio César Torres-Romero
- Laboratorio de Bioquímica y Genética Molecular, Facultad de Química, Universidad Autónoma de Yucatán, Mérida, Yucatán, Mexico
| | | | - Victor Ermilo Arana-Argáez
- Laboratorio de Farmacología, Facultad de Química, Universidad Autónoma de Yucatán, Mérida, Yucatán, Mexico
| | - Karla Acosta-Viana
- Laboratorio de Biología Celular, Centro de Investigaciones Regionales "Dr. Hideyo Noguchi", Universidad Autónoma de Yucatán, Mérida, Yucatán, Mexico
| | - Emanuel Ceballos-Góngora
- Laboratorio de Bioquímica y Genética Molecular, Facultad de Química, Universidad Autónoma de Yucatán, Mérida, Yucatán, Mexico
- Laboratorio de Farmacología, Facultad de Química, Universidad Autónoma de Yucatán, Mérida, Yucatán, Mexico
| | - Laura Vázquez-Carrillo
- Posgrado en Ciencias Genómicas, Universidad Autónoma de la Ciudad de México, Ciudad de México, Mexico
| | - Leidi Alvarez-Sánchez
- Laboratorio de Bioquímica y Genética Molecular, Facultad de Química, Universidad Autónoma de Yucatán, Mérida, Yucatán, Mexico
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Dias-Lopes G, Saboia-Vahia L, Margotti ET, Fernandes NDS, Castro CLDF, Oliveira FO, Peixoto JF, Britto C, Silva FCE, Cuervo P, Jesus JBD. Morphologic study of the effect of iron on pseudocyst formation in Trichomonas vaginalis and its interaction with human epithelial cells. Mem Inst Oswaldo Cruz 2017; 112:664-673. [PMID: 28953994 PMCID: PMC5607515 DOI: 10.1590/0074-02760170032] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Accepted: 04/12/2017] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND Trichomonas vaginalis is the aetiological agent of human trichomoniasis, which is one of the most prevalent sexually transmitted diseases in humans. Iron is an important element for the survival of this parasite and the colonisation of the host urogenital tract. OBJECTIVES In this study, we investigated the effects of iron on parasite proliferation in the dynamics of pseudocyst formation and morphologically characterised iron depletion-induced pseudocysts. METHODS We performed structural and ultrastructural analyses using light microscopy, scanning electron microscopy and transmission electron microscopy. FINDINGS It was observed that iron depletion (i) interrupts the proliferation of T. vaginalis, (ii) induces morphological changes in typical multiplicative trophozoites to spherical non-proliferative, non-motile pseudocysts, and (iii) induces the arrest of cell division at different stages of the cell cycle; (iv) iron is the fundamental element for the maintenance of typical trophozoite morphology; (v) pseudocysts induced by iron depletion are viable and reversible forms; and, finally, (vi) we demonstrated that pseudocysts induced by iron depletion are able to interact with human epithelial cells maintaining their spherical forms. MAIN CONCLUSIONS Together, these data suggest that pseudocysts could be induced as a response to iron nutritional stress and could have a potential role in the transmission and infection of T. vaginalis.
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Affiliation(s)
- Geovane Dias-Lopes
- Fundação Oswaldo Cruz-Fiocruz, Instituto Oswaldo Cruz, Laboratório de Biologia Molecular e Doenças Endêmicas, Rio de Janeiro, RJ, Brasil
| | - Leonardo Saboia-Vahia
- Fundação Oswaldo Cruz-Fiocruz, Instituto Oswaldo Cruz, Laboratório de Pesquisa em Leishmanioses, Rio de Janeiro, RJ, Brasil
| | - Eliane Trindade Margotti
- Universidade Federal de São João Del Rei, Faculdade de Medicina, Departamento de Medicina, São João Del Rei, MG, Brasil
| | - Nilma de Souza Fernandes
- Universidade Federal de São João Del Rei, Faculdade de Medicina, Departamento de Medicina, São João Del Rei, MG, Brasil
| | | | - Francisco Odencio Oliveira
- Fundação Oswaldo Cruz-Fiocruz, Instituto Oswaldo Cruz, Laboratório de Ultraestrutura Celular, Rio de Janeiro, RJ, Brasil
| | - Juliana Figueiredo Peixoto
- Fundação Oswaldo Cruz-Fiocruz, Instituto Oswaldo Cruz, Laboratório de Biologia Molecular e Doenças Endêmicas, Rio de Janeiro, RJ, Brasil
| | - Constança Britto
- Fundação Oswaldo Cruz-Fiocruz, Instituto Oswaldo Cruz, Laboratório de Biologia Molecular e Doenças Endêmicas, Rio de Janeiro, RJ, Brasil
| | - Fernando Costa E Silva
- Universidade Estadual do Norte Fluminense Darcy Ribeiro, Centro de Biociências e Biotecnologia, Laboratório de Biologia Celular e Tecidual, Rio de Janeiro, RJ, Brasil
| | - Patricia Cuervo
- Fundação Oswaldo Cruz-Fiocruz, Instituto Oswaldo Cruz, Laboratório de Pesquisa em Leishmanioses, Rio de Janeiro, RJ, Brasil
| | - José Batista de Jesus
- Fundação Oswaldo Cruz-Fiocruz, Instituto Oswaldo Cruz, Laboratório de Biologia Molecular e Doenças Endêmicas, Rio de Janeiro, RJ, Brasil.,Universidade Federal de São João Del Rei, Faculdade de Medicina, Departamento de Medicina, São João Del Rei, MG, Brasil
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Abstract
SUMMARYIron is an essential element for the survival of trichomonads during host–parasite interaction. The availability of this metal modulates several metabolic pathways of the parasites and regulates the expression of virulence factors such as adhesins and proteolytic enzymes. In this study, we investigated the effect of iron depletion on the morphology and life cycle ofTritrichomonas foetus. Scanning and transmission electron microscopy analyses revealed that depletion of iron from the culture medium (named TYM-DIP inducer medium) induces morphological transformation of typical pear-shaped trophozoites into spherical and non-motile pseudocysts. Remarkably, inoculation of pseudocysts into an iron-rich medium (standard TYM medium), or addition of FeSO4to a TYM-DIP inducer medium reverted the morphological transformation process and typical trophozoites were recovered. These results show that pseudocysts are viable forms of the parasite and highlight the role of iron as a modulator of the parasite phenotype. Although iron is required for the survival ofT. foetus, iron depletion does not cause a cellular collapse of pseudocysts, but instead induces phenotypic alterations, probably in order to allow the parasite to survive conditions of nutritional stress. Together, these findings support previous studies that suggest pseudocysts are a resistance form in the life cycle ofT. foetusand enable new approaches to understanding the multifactorial role of iron in the cell biology of this protozoan parasite.
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Morin-Adeline V, Fraser ST, Stack C, Šlapeta J. Host origin determines pH tolerance of Tritrichomonas foetus isolates from the feline gastrointestinal and bovine urogenital tracts. Exp Parasitol 2015; 157:68-77. [PMID: 26160677 DOI: 10.1016/j.exppara.2015.06.017] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Revised: 06/02/2015] [Accepted: 06/30/2015] [Indexed: 02/02/2023]
Abstract
The ability for protozoan parasites to tolerate pH fluctuations within their niche is critical for the establishment of infection and require the parasite to be capable of adapting to a distinct pH range. We used two host adapted Tritrichomonas foetus isolates, capable of infecting either the digestive tract (pH 5.3-6.6) of feline hosts or the reproductive tract (pH 7.4-7.8) of bovine hosts to address their adaptability to changing pH. Using flow cytometry, we investigated the pH tolerance of the bovine and feline T. foetus isolates over a range of physiologically relevant pH in vitro. Following exposure to mild acid stress (pH 6), the bovine T. foetus isolates showed a significant decrease in cell viability and increased cytoplasmic granularity (p-value < 0.003, p-value < 0.0002) compared to pH 7 and 8 (p-value > 0.7). In contrast, the feline genotype displayed an enhanced capacity to maintain cell morphology and viability (p-value > 0.05). Microscopic assessment revealed that following exposure to a weak acidic stress (pH 6), the bovine T. foetus transformed into rounded parasites with extended cell volumes and displays a decrease in viability. The higher tolerance for acidic extracellular environment of the feline isolate compared to the bovine isolate suggests that pH could be a critical factor in regulating T. foetus infections and host-specificity.
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Affiliation(s)
| | - Stuart T Fraser
- Disciplines of Physiology, Anatomy & Histology, School of Medical Sciences, University of Sydney, NSW, Australia
| | - Colin Stack
- School of Science and Health, University of Western Sydney, NSW, Australia
| | - Jan Šlapeta
- Faculty of Veterinary Science, University of Sydney, NSW, Australia.
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Cellular growth and mitochondrial ultrastructure of leishmania (Viannia) braziliensis promastigotes are affected by the iron chelator 2,2-dipyridyl. PLoS Negl Trop Dis 2013; 7:e2481. [PMID: 24147167 PMCID: PMC3798463 DOI: 10.1371/journal.pntd.0002481] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2013] [Accepted: 08/26/2013] [Indexed: 12/02/2022] Open
Abstract
Background Iron is an essential element for the survival of microorganisms in vitro and in vivo, acting as a cofactor of several enzymes and playing a critical role in host-parasite relationships. Leishmania (Viannia) braziliensis is a parasite that is widespread in the new world and considered the major etiological agent of American tegumentary leishmaniasis. Although iron depletion leads to promastigote and amastigote growth inhibition, little is known about the role of iron in the biology of Leishmania. Furthermore, there are no reports regarding the importance of iron for L. (V.) braziliensis. Methodology/Principal Findings In this study, the effect of iron on the growth, ultrastructure and protein expression of L. (V.) braziliensis was analyzed by the use of the chelator 2,2-dipyridyl. Treatment with 2,2-dipyridyl affected parasites' growth in a dose- and time-dependent manner. Multiplication of the parasites was recovered after reinoculation in fresh culture medium. Ultrastructural analysis of treated promastigotes revealed marked mitochondrial swelling with loss of cristae and matrix and the presence of concentric membranar structures inside the organelle. Iron depletion also induced Golgi disruption and intense cytoplasmic vacuolization. Fluorescence-activated cell sorting analysis of tetramethylrhodamine ester-stained parasites showed that 2,2-dipyridyl collapsed the mitochondrial membrane potential. The incubation of parasites with propidium iodide demonstrated that disruption of mitochondrial membrane potential was not associated with plasma membrane permeabilization. TUNEL assays indicated no DNA fragmentation in chelator-treated promastigotes. In addition, two-dimensional electrophoresis showed that treatment with the iron chelator induced up- or down-regulation of proteins involved in metabolism of nucleic acids and coordination of post-translational modifications, without altering their mRNA levels. Conclusions Iron chelation leads to a multifactorial response that results in cellular collapse, starting with the interruption of cell proliferation and culminating in marked mitochondrial impairment in some parasites and their subsequent cell death, whereas others may survive and resume proliferating. American tegumentary leishmaniasis (ATL) is a neglected disease that is widely distributed in the Americas. The protozoan parasite Leishmania (Viannia) braziliensis is one of the main causative agents of ATL, being responsible for the development of different clinical manifestations of the disease, which ranges from self-healing cutaneous lesions to disseminated and mucocutaneous forms. Because iron is essential for the survival and growth of Leishmania, as it is required for colonization of macrophages and development of lesions in mice, several chelating compounds have been tested for their effects on the growth of these parasites. In the present work, treatment of L. (V.) braziliensis with the iron chelator 2,2-dipyridyl inhibited the growth of promastigote forms in a dose- and time-dependent manner. However, multiplication of the parasites was recovered after reinoculation in fresh culture medium. The iron chelator also induced mitochondrial dysfunction and altered expression of proteins involved in metabolism of nucleic acids and coordination of post-translational modifications. The events described above ultimately caused the death of some parasites, most likely due to mitochondrial dysfunction, whereas others adapted and survived, suggesting a plasticity or resilience of the mitochondrion in this parasite.
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Petrópolis DB, Fernandes Rodrigues JC, da Rocha-Azevedo B, Silva-Filho FCE. The binding of Tritrichomonas foetus to immobilized laminin-1 and its role in the cytotoxicity exerted by the parasite. Microbiology (Reading) 2008; 154:2283-2290. [DOI: 10.1099/mic.0.2007/015941-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
| | | | - Bruno da Rocha-Azevedo
- UFRJ – Instituto de Biofísica Carlos Chagas Filho, CCS – Bloco G, Rio de Janeiro, Brazil
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De Jesus JB, Cuervo P, Junqueira M, Britto C, Silva-Filho FCE, Soares MJ, Cupolillo E, Fernandes O, Domont GB. A further proteomic study on the effect of iron in the human pathogen Trichomonas vaginalis. Proteomics 2007; 7:1961-72. [PMID: 17514679 DOI: 10.1002/pmic.200600797] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Iron is an essential element to support the growth and survival of Trichomonas vaginalis. It plays a critical role in the host-parasite interaction, and modulates the expression of virulence factors in this protozoan. In this work, parasites grown in iron-rich and iron-depleted media were analyzed by (i) light and scanning electron microscopy and (ii) 2-DE and MS. Withdrawal of iron from the culture medium resulted in dramatic changes in both the morphology and in the proteome pattern of T. vaginalis. Trophozoites underwent transformation from ellipsoid or amoeboid forms to rounded cells, whose flagella and axostyle were internalized. Forty-five proteins differentially expressed in parasites cultivated in the absence of iron were identified. In iron-depleted parasites, enzymes involved in energetic metabolism, proteolysis and hydrogenosomal iron-sulfur (Fe-S) proteins were down-regulated or even suppressed. Among up-regulated proteins, six isoforms of actin were detected. In addition, phosphoenolpyruvate carboxykinase, putative lactate dehydrogenase, and putative adenosine triphosphatase were also up-regulated or were exclusively observed in gels related to iron-depleted parasites. Our data demonstrate that iron has a pivotal role in the regulation of the morphological transformation of T. vaginalis and modulates the expression of both Fe-S and non-Fe-S proteins in the parasite.
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Affiliation(s)
- Jose Batista De Jesus
- Departamento de Bioquímica e Biologia Molecular, Instituto Oswaldo Cruz-FIOCRUZ, Rio de Janeiro, RJ, Brasil.
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8
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Alvarez-Sánchez ME, Solano-González E, Yañez-Gómez C, Arroyo R. Negative iron regulation of the CP65 cysteine proteinase cytotoxicity in Trichomonas vaginalis. Microbes Infect 2007; 9:1597-605. [PMID: 18023389 DOI: 10.1016/j.micinf.2007.09.011] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2007] [Accepted: 09/11/2007] [Indexed: 11/30/2022]
Abstract
Several cysteine proteinases (CPs) participate in the virulence of Trichomonas vaginalis. One of them is a 65kDa CP, CP65, involved in cytotoxicity. The aim of this work was to investigate the effect of iron on the trichomonal CP65-dependent cytotoxicity using parasites grown under distinct iron concentrations. Cytotoxicity and cell-binding assays, and zymograms were performed. At the highest iron concentration (250 microM), parasites exhibited the lowest levels of cytotoxicity and less CP65 proteolytic activity. Other cations in the culture medium did not affect the trichomonal CP65-dependent cytotoxicity as iron did. Another four trichomonad fresh isolates presented similar iron negative effect over cytotoxicity. Western blot and RT-PCR experiments also showed reduction in the amount of protein and transcript of CP65 in trichomonads grown under iron-rich conditions, as compared with parasites grown in normal and iron-depleted media. Indirect immunofluorescence using the anti-CP65 antibody showed that parasites grown in iron-rich medium expressed less CP65 than those grown in normal and iron-depleted media. Cytotoxicity inhibition experiments with the anti-CP65 antibody confirmed the iron negative effect over the CP65-dependent cytotoxicity. In conclusion, our data show that iron specifically down-regulates proteolytic activity, expression, and transcription of CP65, negatively affecting trichomonal cytotoxicity in vitro.
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Affiliation(s)
- María Elizbeth Alvarez-Sánchez
- Departamento de Patología Experimental, Centro de Investigación y de Estudios Avanzados del IPN (CINVESTAV-IPN), Av IPN 2508, Col. San Pedro Zacatenco, Mexico City, CP 07360, Mexico
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De Jesus JB, Ferreira MA, Cuervo P, Britto C, e Silva-Filho FC, Meyer-Fernandes JR. Iron modulates ecto-phosphohydrolase activities in pathogenic trichomonads. Parasitol Int 2006; 55:285-90. [PMID: 17010660 DOI: 10.1016/j.parint.2006.08.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2006] [Revised: 07/21/2006] [Accepted: 08/21/2006] [Indexed: 11/27/2022]
Abstract
The presence of iron in the extracellular medium is essential for both in vivo and in vitro survival of pathogenic microorganisms, including Trichomonas vaginalis and Tritrichomonas foetus. In these parasites, iron is directly involved in the proliferation, protein expression and activation of critical enzymes. The purpose of this study was to investigate the role of iron in ecto-ATPase, ecto-phophatase and secreted phosphatase activities of these trichomonads. We observed that trichomonads grown in iron-depleted medium exhibited a remarkable decrease in both ecto-ATPase and ecto-phosphatase activities, when compared to those cultivated under control conditions (iron-rich medium). Furthermore, parasites grown in iron-depleted medium restored their enzyme activities when they were re-inoculated into fresh iron-rich medium. We demonstrated that modulation of ecto-phosphohydrolase activities is due neither to enzyme-iron nor to substrate-iron complex formation, since iron addition directly to the medium where the enzymatic reactions occurred did not alter their activities. Previously, we had reported that a fresh clinical isolate of T. vaginalis was much more cytotoxic to epithelial cell monolayers than a long-term cultured one. In this study we witnessed that the fresh isolate of T. vaginalis presented higher activities to all herein investigated enzymes than the long-term cultured one. Altogether, our data clearly point out that iron has a pivotal role in the expression of phosphohydrolases in both trichomonads.
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Affiliation(s)
- José Batista De Jesus
- Departamento de Bioquímica e Biologia Molecular, Instituto Oswaldo Cruz, Pav Leônidas Deane, Brasil, 4365, Manguinhos, Rio de Janeiro, RJ, Brazil.
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Cuervo P, Sabóia-Vahia L, Costa Silva-Filho F, Fernandes O, Cupolillo E, DE Jesus JB. A zymographic study of metalloprotease activities in extracts and extracellular secretions of Leishmania (Viannia) braziliensis strains. Parasitology 2005; 132:177-85. [PMID: 16197592 DOI: 10.1017/s0031182005008942] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2005] [Revised: 06/24/2005] [Accepted: 08/04/2005] [Indexed: 11/06/2022]
Abstract
Proteolytic activities of 5 strains of Leishmania (Viannia) braziliensis isolated from Brazilian and Colombian patients, presenting distinct clinical manifestations, were characterized and compared using whole-promastigote extracts and extracellular secretions. Zymographic assays concerning whole-cell extracts and supernatants resulted in the detection of high molecular weight bands, ranging from 50 to 125 kDa. Proteolytic activities from both whole-cell extracts and supernatants were optimal in a pH range 5.5 to 9.0 for all analysed strains. Such protease activities were inhibited when 10 mM 1,10-phenanthroline was assayed, strongly suggesting that the enzymes responsible for hydrolysis of the substrate belong to the metalloproteases class. Distinct profiles of metalloproteases were observed among the studied L. (V.) braziliensis strains. Differences among the microorganisms might be related to the geographical origin of the strains and/or to the clinical presentation.
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Affiliation(s)
- P Cuervo
- Departamento de Medicina Tropical, Instituto Oswaldo Cruz, FIOCRUZ, Rio de Janeiro, Brasil
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da Rocha-Azevedo B, de Melo-Braga MB, e Silva-Filho FC. Intra-strain clonal phenotypic variation of Tritrichomonas foetus is related to the cytotoxicity exerted by the parasite to cultured cells. Parasitol Res 2004; 95:106-12. [PMID: 15666185 DOI: 10.1007/s00436-004-1251-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2004] [Accepted: 09/27/2004] [Indexed: 11/30/2022]
Abstract
As observed in most of the investigated trichomonads, a strain of Tritrichomonas foetus includes different parasite subpopulations. Such population diversity might account for important properties such as the ability of the parasite to destroy host cells. The aim of this study was to characterize the cytotoxicity exerted by subpopulations (named as K1, K2, K3, K4 and K5) of an isolate of T. foetus on epithelial cultured cells. The five populations studied here destroyed epithelial monolayers at different rates (from 25% to 55%), even though the cytoadhesion level and whole-cell protease activity were closely related among them. We were also able to detect differences in contact-dependent and contact-independent cytotoxicity mechanisms among the five populations. An extracellular parasite protease had varying activity among the parasite populations. The intensity of contact-independent cytotoxicity was strictly related to the degree of enzyme activation, suggesting that such a protease might be involved in the cytotoxicity mediated by T. foetus.
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Affiliation(s)
- Bruno da Rocha-Azevedo
- Laboratório de Biologia da Superfície Celular, Programa de Bioengenharia e Biotecnologia Animal, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
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