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Zhao J, Yu X, Shentu X, Li D. The application and development of electron microscopy for three-dimensional reconstruction in life science: a review. Cell Tissue Res 2024; 396:1-18. [PMID: 38416172 DOI: 10.1007/s00441-024-03878-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Accepted: 02/13/2024] [Indexed: 02/29/2024]
Abstract
Imaging technologies have played a pivotal role in advancing biological research by enabling visualization of biological structures and processes. While traditional electron microscopy (EM) produces two-dimensional images, emerging techniques now allow high-resolution three-dimensional (3D) characterization of specimens in situ, meeting growing needs in molecular and cellular biology. Combining transmission electron microscopy (TEM) with serial sectioning inaugurated 3D imaging, attracting biologists seeking to explore cell ultrastructure and driving advancement of 3D EM reconstruction. By comprehensively and precisely rendering internal structure and distribution, 3D TEM reconstruction provides unparalleled ultrastructural insights into cells and molecules, holding tremendous value for elucidating structure-function relationships and broadly propelling structural biology. Here, we first introduce the principle of 3D reconstruction of cells and tissues by classical approaches in TEM and then discuss modern technologies utilizing TEM and on new SEM-based as well as cryo-electron microscope (cryo-EM) techniques. 3D reconstruction techniques from serial sections, electron tomography (ET), and the recent single-particle analysis (SPA) are examined; the focused ion beam scanning electron microscopy (FIB-SEM), the serial block-face scanning electron microscopy (SBF-SEM), and automatic tape-collecting lathe ultramicrotome (ATUM-SEM) for 3D reconstruction of large volumes are discussed. Finally, we review the challenges and development prospects of these technologies in life science. It aims to provide an informative reference for biological researchers.
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Affiliation(s)
- Jingjing Zhao
- Zhejiang Provincial Key Laboratory of Biometrology and Inspection and Quarantine, College of Life Science, China , Jiliang University, Hangzhou, 310018, China
| | - Xiaoping Yu
- Zhejiang Provincial Key Laboratory of Biometrology and Inspection and Quarantine, College of Life Science, China , Jiliang University, Hangzhou, 310018, China
| | - Xuping Shentu
- Zhejiang Provincial Key Laboratory of Biometrology and Inspection and Quarantine, College of Life Science, China , Jiliang University, Hangzhou, 310018, China
| | - Danting Li
- Zhejiang Provincial Key Laboratory of Biometrology and Inspection and Quarantine, College of Life Science, China , Jiliang University, Hangzhou, 310018, China.
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2
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de Freitas V, Costa TR, Nogueira AR, Polloni L, Alves de Melo Fernandes T, Correia LIV, Borges BC, Teixeira SC, Silva MJB, Amorim FG, Quinton L, Saraiva AL, Espindola FS, Iwai LK, Rodrigues RS, Yoneyama KAG, de Melo Rodrigues Ávila V. Biochemical characterization and assessment of leishmanicidal effects of a new L-amino acid oxidase from Crotalus durissus collilineatus snake venom (CollinLA AO-I). Toxicon 2023; 230:107156. [PMID: 37169266 DOI: 10.1016/j.toxicon.2023.107156] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Revised: 05/04/2023] [Accepted: 05/08/2023] [Indexed: 05/13/2023]
Abstract
This study reports the isolation of CollinLAAO-I, a new L-amino acid oxidase from Crotalus durissus collilineatus snake venom, its biochemical characterization and leishmanicidal potential in Leishmania spp. CollinLAAO-I (63.1 kDa) was successfully isolated with high purity using two chromatographic steps and represents 2.5% of total venom proteins. CollinLAAO-I displayed high enzymatic activity (4262.83 U/mg/min), significantly reducing after 28 days. The enzymatic activity of CollinLAAO-I revealed higher affinity for hydrophobic amino acids such as L-leucine, high enzymatic activity in a wide pH range (6.0-10.0), at temperatures from 0 to 25 °C, and showed complete inhibition in the presence of Na+ and K+. Cytotoxicity assays revealed IC50 of 18.49 and 11.66 μg/mL for Leishmania (L.) amazonensis and Leishmania (L.) infantum, respectively, and the cytotoxicity was completely suppressed by catalase. CollinLAAO-I significantly increased the intracellular concentration of reactive oxygen species (ROS) and reduced the mitochondrial potential of both Leishmania species. Furthermore, CollinLAAO-I decreased the parasite capacity to infect macrophages by around 70%, indicating that even subtoxic concentrations of CollinLAAO-I can interfere with Leishmania vital processes. Thus, the results obtained for CollinLAAO-I provide important support for developing therapeutic strategies against leishmaniasis.
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Affiliation(s)
- Vitor de Freitas
- Laboratory of Biochemistry and Animal Toxins, Institute of Biotechnology, Federal University of Uberlândia - UFU, Uberlândia, MG, Brazil
| | - Tássia Rafaella Costa
- Laboratory of Biochemistry and Animal Toxins, Institute of Biotechnology, Federal University of Uberlândia - UFU, Uberlândia, MG, Brazil
| | - Amanda Rodrigues Nogueira
- Laboratory of Biochemistry and Animal Toxins, Institute of Biotechnology, Federal University of Uberlândia - UFU, Uberlândia, MG, Brazil
| | - Lorena Polloni
- Laboratory of Biochemistry and Animal Toxins, Institute of Biotechnology, Federal University of Uberlândia - UFU, Uberlândia, MG, Brazil
| | - Thales Alves de Melo Fernandes
- Laboratory of Biochemistry and Animal Toxins, Institute of Biotechnology, Federal University of Uberlândia - UFU, Uberlândia, MG, Brazil
| | - Lucas Ian Veloso Correia
- Laboratory of Biochemistry and Animal Toxins, Institute of Biotechnology, Federal University of Uberlândia - UFU, Uberlândia, MG, Brazil
| | - Bruna Cristina Borges
- Laboratory of Osteoimmunology and Tumor Immunology, Institute of Biomedical Sciences, Federal University of Uberlândia - UFU, Uberlândia, MG, Brazil
| | - Samuel Cota Teixeira
- Laboratory of Biochemistry and Animal Toxins, Institute of Biotechnology, Federal University of Uberlândia - UFU, Uberlândia, MG, Brazil
| | - Marcelo José Barbosa Silva
- Laboratory of Osteoimmunology and Tumor Immunology, Institute of Biomedical Sciences, Federal University of Uberlândia - UFU, Uberlândia, MG, Brazil
| | - Fernanda Gobbi Amorim
- Laboratory of Mass Spectrometry, Department of Chemistry, University of Liège, Liège, Belgium
| | - Loïc Quinton
- Laboratory of Mass Spectrometry, Department of Chemistry, University of Liège, Liège, Belgium
| | - André Lopes Saraiva
- Laboratory of Biochemistry and Molecular Biology, Institute of Biotechnology, Federal University of Uberlândia - UFU, Uberlândia, MG, Brazil
| | - Foued Salmen Espindola
- Laboratory of Biochemistry and Molecular Biology, Institute of Biotechnology, Federal University of Uberlândia - UFU, Uberlândia, MG, Brazil
| | - Leo Kei Iwai
- Laboratory of Applied Toxinology (LETA) and Center of Toxins, Immune-Response and Cell Signaling (CeTICS), Butantan Institute, São Paulo, SP, Brazil
| | - Renata Santos Rodrigues
- Laboratory of Biochemistry and Animal Toxins, Institute of Biotechnology, Federal University of Uberlândia - UFU, Uberlândia, MG, Brazil
| | - Kelly Aparecida Geraldo Yoneyama
- Laboratory of Biochemistry and Animal Toxins, Institute of Biotechnology, Federal University of Uberlândia - UFU, Uberlândia, MG, Brazil
| | - Veridiana de Melo Rodrigues Ávila
- Laboratory of Biochemistry and Animal Toxins, Institute of Biotechnology, Federal University of Uberlândia - UFU, Uberlândia, MG, Brazil.
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3
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Michels PAM, Gualdrón-López M. Biogenesis and metabolic homeostasis of trypanosomatid glycosomes: new insights and new questions. J Eukaryot Microbiol 2022; 69:e12897. [PMID: 35175680 DOI: 10.1111/jeu.12897] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Revised: 02/14/2022] [Accepted: 02/14/2022] [Indexed: 11/28/2022]
Abstract
Kinetoplastea and Diplonemea possess peroxisome-related organelles that, uniquely, contain most of the enzymes of the glycolytic pathway and are hence called glycosomes. Enzymes of several other core metabolic pathways have also been located in glycosomes, in addition to some characteristic peroxisomal systems such as pathways of lipid metabolism. A considerable amount of research has been performed on glycosomes of trypanosomes since their discovery four decades ago. Not only the role of the glycosomal enzyme systems in the overall cell metabolism appeared to be unique, but the organelles display also remarkable features regarding their biogenesis and structural properties. These features are similar to those of the well-studied peroxisomes of mammalian and plant cells and yeasts yet exhibit also differences reflecting the large evolutionary distance between these protists and the representatives of other major eukaryotic lineages. Despite all research performed, many questions remain about various properties and the biological roles of glycosomes and peroxisomes. Here we review the current knowledge about glycosomes, often comparing it with information about peroxisomes. Furthermore, we highlight particularly many questions that remain about the biogenesis, and the heterogeneity in structure and content of these enigmatic organelles, and the properties of their boundary membrane.
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Affiliation(s)
- Paul A M Michels
- Centre for Immunity, Infection and Evolution and Centre for Translational and Chemical Biology, The University of Edinburgh, Edinburgh, United Kingdom
| | - Melisa Gualdrón-López
- Instituto Salud Global, Hospital Clinic-Universitat de Barcelona, and Institute for Health Sciences Trias i Pujol, Barcelona, Spain
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4
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Barbosa LG, Costa TR, Borges IP, Costa MS, Carneiro AC, Borges BC, Silva MJB, Amorim FG, Quinton L, Yoneyama KAG, de Melo Rodrigues V, Sampaio SV, Rodrigues RS. A comparative study on the leishmanicidal activity of the L-amino acid oxidases BjussuLAAO-II and BmooLAAO-II isolated from Brazilian Bothrops snake venoms. Int J Biol Macromol 2020; 167:267-278. [PMID: 33242552 DOI: 10.1016/j.ijbiomac.2020.11.146] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Revised: 11/18/2020] [Accepted: 11/20/2020] [Indexed: 12/13/2022]
Abstract
This study aims to examine whether two L-amino acid oxidases isolated from Bothrops snake venom (SV-LAAOs) were cytotoxic to Leishmania (Leishmania) amazonensis and Leishmania (Viannia) braziliensis, two causative agents of leishmaniasis, which is an endemic disease in tropical and subtropical countries. The SV-LAAOs BjussuLAAO-II and BmooLAAO-II were isolated from Bothrops jararacussu and Bothrops moojeni venom, respectively, through a three-step chromatography process that used molecular exclusion, hydrophobic interaction, and affinity columns. BmooLAAO-II is a new SV-LAAO isoform that we isolated in this study. The purified BjussuLAAO-II and BmooLAAO-II had high L-amino acid oxidase-specific activity: 3481.17 and 4924.77 U/mg/min, respectively. Both SV-LAAOs were strongly cytotoxic to the two Leishmania species, even at low concentrations. At the same concentration, BjussuLAAO-II and BmooLAAO-II exerted different cytotoxic effects on the parasites. We reported for the first time that the SV-LAAOs suppressed cell proliferation and altered the mitochondrial membrane potential of the two Leishmania species. Surprisingly, BjussuLAAO-II increased the intracellular reactive oxygen species production only in L. (L.) amazonensis, while BmooLAAO-II increased the intracellular reactive oxygen species production only in L. (V.) braziliensis, indicating that these SV-LAAOs had a certain specificity of action.
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Affiliation(s)
- Luana Gonçalves Barbosa
- Laboratory of Biochemistry and Animal Toxins, Institute of Biotechnology, Federal University of Uberlândia - UFU, Uberlândia, MG, Brazil
| | - Tássia Rafaella Costa
- Laboratory of Biochemistry and Animal Toxins, Institute of Biotechnology, Federal University of Uberlândia - UFU, Uberlândia, MG, Brazil
| | - Isabela Pacheco Borges
- Laboratory of Biochemistry and Animal Toxins, Institute of Biotechnology, Federal University of Uberlândia - UFU, Uberlândia, MG, Brazil
| | - Mônica Soares Costa
- Laboratory of Biochemistry and Animal Toxins, Institute of Biotechnology, Federal University of Uberlândia - UFU, Uberlândia, MG, Brazil
| | - Anna Cecília Carneiro
- Laboratory of Biochemistry and Animal Toxins, Institute of Biotechnology, Federal University of Uberlândia - UFU, Uberlândia, MG, Brazil
| | - Bruna Cristina Borges
- Laboratory of Osteoimmunology and Tumor Immunology, Institute of Biomedical Sciences, Federal University of Uberlândia - UFU, Uberlândia, MG, Brazil
| | - Marcelo José Barbosa Silva
- Laboratory of Osteoimmunology and Tumor Immunology, Institute of Biomedical Sciences, Federal University of Uberlândia - UFU, Uberlândia, MG, Brazil
| | - Fernanda Gobbi Amorim
- Laboratory of Mass Spectrometry, Department of Chemistry, University of Liège, Liège, Belgium
| | - Loïc Quinton
- Laboratory of Mass Spectrometry, Department of Chemistry, University of Liège, Liège, Belgium
| | - Kelly Aparecida Geraldo Yoneyama
- Laboratory of Biochemistry and Animal Toxins, Institute of Biotechnology, Federal University of Uberlândia - UFU, Uberlândia, MG, Brazil
| | - Veridiana de Melo Rodrigues
- Laboratory of Biochemistry and Animal Toxins, Institute of Biotechnology, Federal University of Uberlândia - UFU, Uberlândia, MG, Brazil
| | - Suely Vilela Sampaio
- Department of Clinical Analyses, Toxicology and Food Sciences, School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo - USP, Ribeirão Preto, SP, Brazil
| | - Renata Santos Rodrigues
- Laboratory of Biochemistry and Animal Toxins, Institute of Biotechnology, Federal University of Uberlândia - UFU, Uberlândia, MG, Brazil.
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5
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Cull B, Prado Godinho JL, Fernandes Rodrigues JC, Frank B, Schurigt U, Williams RA, Coombs GH, Mottram JC. Glycosome turnover in Leishmania major is mediated by autophagy. Autophagy 2015; 10:2143-57. [PMID: 25484087 PMCID: PMC4502677 DOI: 10.4161/auto.36438] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Autophagy is a central process behind the cellular remodeling that occurs during differentiation of Leishmania, yet the cargo of the protozoan parasite's autophagosome is unknown. We have identified glycosomes, peroxisome-like organelles that uniquely compartmentalize glycolytic and other metabolic enzymes in Leishmania and other kinetoplastid parasitic protozoa, as autophagosome cargo. It has been proposed that the number of glycosomes and their content change during the Leishmania life cycle as a key adaptation to the different environments encountered. Quantification of RFP-SQL-labeled glycosomes showed that promastigotes of L. major possess ~20 glycosomes per cell, whereas amastigotes contain ~10. Glycosome numbers were significantly greater in promastigotes and amastigotes of autophagy-defective L. major Δatg5 mutants, implicating autophagy in glycosome homeostasis and providing a partial explanation for the previously observed growth and virulence defects of these mutants. Use of GFP-ATG8 to label autophagosomes showed glycosomes to be cargo in ~15% of them; glycosome-containing autophagosomes were trafficked to the lysosome for degradation. The number of autophagosomes increased 10-fold during differentiation, yet the percentage of glycosome-containing autophagosomes remained constant. This indicates that increased turnover of glycosomes was due to an overall increase in autophagy, rather than an upregulation of autophagosomes containing this cargo. Mitophagy of the single mitochondrion was not observed in L. major during normal growth or differentiation; however, mitochondrial remnants resulting from stress-induced fragmentation colocalized with autophagosomes and lysosomes, indicating that autophagy is used to recycle these damaged organelles. These data show that autophagy in Leishmania has a central role not only in maintaining cellular homeostasis and recycling damaged organelles but crucially in the adaptation to environmental change through the turnover of glycosomes.
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Affiliation(s)
- Benjamin Cull
- a Wellcome Trust Center for Molecular Parasitology; Institute of Infection, Immunity and Inflammation; College of Medical, Veterinary and Life Sciences ; University of Glasgow ; Glasgow , UK
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6
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Miranda K, Girard-Dias W, Attias M, de Souza W, Ramos I. Three dimensional reconstruction by electron microscopy in the life sciences: An introduction for cell and tissue biologists. Mol Reprod Dev 2015; 82:530-47. [PMID: 25652003 DOI: 10.1002/mrd.22455] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Accepted: 12/10/2014] [Indexed: 12/26/2022]
Abstract
Early applications of transmission electron microscopy (TEM) in the life sciences have contributed tremendously to our current understanding at the subcellular level. Initially limited to two-dimensional representations of three-dimensional (3D) objects, this approach has revolutionized the fields of cellular and structural biology-being instrumental for determining the fine morpho-functional characterization of most cellular structures. Electron microscopy has progressively evolved towards the development of tools that allow for the 3D characterization of different structures. This was done with the aid of a wide variety of techniques, which have become increasingly diverse and highly sophisticated. We start this review by examining the principles of 3D reconstruction of cells and tissues using classical approaches in TEM, and follow with a discussion of the modern approaches utilizing TEM as well as on new scanning electron microscopy-based techniques. 3D reconstruction techniques from serial sections and (cryo) electron-tomography are examined, and the recent applications of focused ion beam-scanning microscopes and serial-block-face techniques for the 3D reconstruction of large volumes are discussed. Alternative low-cost techniques and more accessible approaches using basic transmission or field emission scanning electron microscopes are also examined.
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Affiliation(s)
- Kildare Miranda
- Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica, Carlos Chagas Filho and Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Bioimagens-Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.,Diretoria de Metrologia Aplicada a Ciências da Vida, Instituto Nacional de Metrologia, Qualidade e Tecnologia (INMETRO), Xer, é, m, Rio de Janeiro, Brazil
| | - Wendell Girard-Dias
- Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica, Carlos Chagas Filho and Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Bioimagens-Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Marcia Attias
- Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica, Carlos Chagas Filho and Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Bioimagens-Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Wanderley de Souza
- Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica, Carlos Chagas Filho and Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Bioimagens-Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.,Diretoria de Metrologia Aplicada a Ciências da Vida, Instituto Nacional de Metrologia, Qualidade e Tecnologia (INMETRO), Xer, é, m, Rio de Janeiro, Brazil
| | - Isabela Ramos
- Laboratório de Bioquímica de Insetos, Instituto de Bioquímica Médica, Leopoldo de Meis -Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
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Brennand A, Rico E, Michels PAM. Autophagy in trypanosomatids. Cells 2012; 1:346-71. [PMID: 24710480 PMCID: PMC3901119 DOI: 10.3390/cells1030346] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2012] [Revised: 07/14/2012] [Accepted: 07/16/2012] [Indexed: 01/07/2023] Open
Abstract
Autophagy is a ubiquitous eukaryotic process that also occurs in trypanosomatid parasites, protist organisms belonging to the supergroup Excavata, distinct from the supergroup Opistokontha that includes mammals and fungi. Half of the known yeast and mammalian AuTophaGy (ATG) proteins were detected in trypanosomatids, although with low sequence conservation. Trypanosomatids such as Trypanosoma brucei, Trypanosoma cruzi and Leishmania spp. are responsible for serious tropical diseases in humans. The parasites are transmitted by insects and, consequently, have a complicated life cycle during which they undergo dramatic morphological and metabolic transformations to adapt to the different environments. Autophagy plays a major role during these transformations. Since inhibition of autophagy affects the transformation, survival and/or virulence of the parasites, the ATGs offer promise for development of drugs against tropical diseases. Furthermore, various trypanocidal drugs have been shown to trigger autophagy-like processes in the parasites. It is inferred that autophagy is used by the parasites in an-not always successful-attempt to cope with the stress caused by the toxic compounds.
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Affiliation(s)
- Ana Brennand
- Research Unit for Tropical Diseases, de Duve Institute, Université catholique de Louvain, Avenue Hippocrate 74, postal box B1.74.01, B-1200 Brussels, Belgium.
| | - Eva Rico
- Department of Biochemistry and Molecular Biology, University Campus, University of Alcalá, Alcalá de Henares, Madrid, 28871, Spain.
| | - Paul A M Michels
- Research Unit for Tropical Diseases, de Duve Institute, Université catholique de Louvain, Avenue Hippocrate 74, postal box B1.74.01, B-1200 Brussels, Belgium.
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8
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Williams RAM, Smith TK, Cull B, Mottram JC, Coombs GH. ATG5 is essential for ATG8-dependent autophagy and mitochondrial homeostasis in Leishmania major. PLoS Pathog 2012; 8:e1002695. [PMID: 22615560 PMCID: PMC3355087 DOI: 10.1371/journal.ppat.1002695] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2011] [Accepted: 03/01/2012] [Indexed: 01/05/2023] Open
Abstract
Macroautophagy has been shown to be important for the cellular remodelling required for Leishmania differentiation. We now demonstrate that L. major contains a functional ATG12-ATG5 conjugation system, which is required for ATG8-dependent autophagosome formation. Nascent autophagosomes were found commonly associated with the mitochondrion. L. major mutants lacking ATG5 (Δatg5) were viable as promastigotes but were unable to form autophagosomes, had morphological abnormalities including a much reduced flagellum, were less able to differentiate and had greatly reduced virulence to macrophages and mice. Analyses of the lipid metabolome of Δatg5 revealed marked elevation of phosphatidylethanolamines (PE) in comparison to wild type parasites. The Δatg5 mutants also had increased mitochondrial mass but reduced mitochondrial membrane potential and higher levels of reactive oxygen species. These findings indicate that the lack of ATG5 and autophagy leads to perturbation of the phospholipid balance in the mitochondrion, possibly through ablation of membrane use and conjugation of mitochondrial PE to ATG8 for autophagosome biogenesis, resulting in a dysfunctional mitochondrion with impaired oxidative ability and energy generation. The overall result of this is reduced virulence. Leishmaniasis is a disease of humans that is of major significance throughout many parts of the world. It is caused by the protozoan parasite Leishmania and mammals are infected through the bite of a sand fly in which the parasite develops. Parasite remodelling crucial for generation of the human-infective forms is aided by the catabolic process known as autophagy in which cell material is packaged within organelles called autophagosomes and subsequently broken down in the digestive lysosomal compartment. Here we show that autophagy in Leishmania requires the coordinated actions of two pathways, one of which involves a protein called ATG5. We have generated parasite mutants lacking this protein and shown that ATG5 is required for both autophagosome formation and also maintenance of a fully functional mitochondrion. The mutants lacking ATG5 have increased mitochondrial mass and phospholipid content, high levels of oxidants and reduced membrane potential, all being hallmarks of a dysfunctional mitochondrion with impaired ability for energy generation. Our results have thus revealed that a functional autophagic pathway is crucial for phospholipid homeostasis and mitochondrial function in the parasite and important for the parasite's differentiation, infectivity and virulence to its mammalian host.
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Affiliation(s)
- Roderick A. M. Williams
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, United Kingdom
| | - Terry K. Smith
- Schools of Biology & Chemistry, The University of St. Andrews, St. Andrews, United Kingdom
| | - Benjamin Cull
- Wellcome Trust Centre for Molecular Parasitology, Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Jeremy C. Mottram
- Wellcome Trust Centre for Molecular Parasitology, Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Graham H. Coombs
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, United Kingdom
- * E-mail:
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9
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Brennand A, Gualdrón-López M, Coppens I, Rigden DJ, Ginger ML, Michels PA. Autophagy in parasitic protists: Unique features and drug targets. Mol Biochem Parasitol 2011; 177:83-99. [DOI: 10.1016/j.molbiopara.2011.02.003] [Citation(s) in RCA: 92] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2010] [Revised: 01/30/2011] [Accepted: 02/02/2011] [Indexed: 12/24/2022]
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10
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Duszenko M, Ginger ML, Brennand A, Gualdrón-López M, Colombo MI, Coombs GH, Coppens I, Jayabalasingham B, Langsley G, de Castro SL, Menna-Barreto R, Mottram JC, Navarro M, Rigden DJ, Romano PS, Stoka V, Turk B, Michels PAM. Autophagy in protists. Autophagy 2011; 7:127-58. [PMID: 20962583 DOI: 10.4161/auto.7.2.13310] [Citation(s) in RCA: 133] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Autophagy is the degradative process by which eukaryotic cells digest their own components using acid hydrolases within the lysosome. Originally thought to function almost exclusively in providing starving cells with nutrients taken from their own cellular constituents, autophagy is in fact involved in numerous cellular events including differentiation, turnover of macromolecules and organelles, and defense against parasitic invaders. During the last 10-20 years, molecular components of the autophagic machinery have been discovered, revealing a complex interactome of proteins and lipids, which, in a concerted way, induce membrane formation to engulf cellular material and target it for lysosomal degradation. Here, our emphasis is autophagy in protists. We discuss experimental and genomic data indicating that the canonical autophagy machinery characterized in animals and fungi appeared prior to the radiation of major eukaryotic lineages. Moreover, we describe how comparative bioinformatics revealed that this canonical machinery has been subject to moderation, outright loss or elaboration on multiple occasions in protist lineages, most probably as a consequence of diverse lifestyle adaptations. We also review experimental studies illustrating how several pathogenic protists either utilize autophagy mechanisms or manipulate host-cell autophagy in order to establish or maintain infection within a host. The essentiality of autophagy for the pathogenicity of many parasites, and the unique features of some of the autophagy-related proteins involved, suggest possible new targets for drug discovery. Further studies of the molecular details of autophagy in protists will undoubtedly enhance our understanding of the diversity and complexity of this cellular phenomenon and the opportunities it offers as a drug target.
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Affiliation(s)
- Michael Duszenko
- Interfaculty Institute for Biochemistry, University of Tübingen, Tübingen, Germany
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11
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Campos FM, Liarte DB, Mortara RA, Romanha AJ, Murta SM. Characterization of a gene encoding alcohol dehydrogenase in benznidazole-susceptible and -resistant populations of Trypanosoma cruzi. Acta Trop 2009; 111:56-63. [PMID: 19426664 DOI: 10.1016/j.actatropica.2009.02.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2008] [Revised: 01/29/2009] [Accepted: 02/23/2009] [Indexed: 10/21/2022]
Abstract
Alcohol dehydrogenases (ADH) are a class of oxidoreductases that catalyse the reversible oxidation of ethanol to acetaldehyde. In the human parasite Trypanosoma cruzi the TcADH gene was identified through microarray analysis as having reduced transcription in an in vitro induced benznidazole (BZ)-resistant population. In the present study, we have extended these results by characterizing the TcADH gene from 11 strains of T. cruzi that were either susceptible or naturally resistant to benznidazole and nifurtimox or had in vivo selected or in vitro induced resistance to BZ. Sequence comparisons showed that TcADH was more similar to prokaryotic ADHs than to orthologs identified Leishmania spp. Immunolocalisation using confocal microscopy revealed that TcADH is present in the kinetoplast region and along the parasite body, consistent with the mitochondrial localization predicted by sequence analysis. Northern blots showed a 1.9kb transcript with similar signal intensity in all T. cruzi samples analysed, except for the in vitro selected resistant population, where transcript levels were 2-fold lower. These findings were confirmed by quantitative real-time PCR. In Western blot analysis, anti-TcADH polyclonal antisera recognised a 42kDa protein in all T. cruzi strains tested. The level of expression of this polypeptide was approximately 2-fold lower in the in vitro induced benznidazole-resistant strain, than in the susceptible parental strain. The chromosomal location of the TcADH gene was variable, but was not associated with the zymodeme or with the drug resistance phenotype. The data presented here show that the TcADH enzyme has a decreased level of expression in the in vitro induced BZ-resistant T. cruzi population, a situation that has not been observed in the in vivo selected BZ-resistant and naturally resistant strains.
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12
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de Souza W, Sant'Anna C, Cunha-e-Silva NL. Electron microscopy and cytochemistry analysis of the endocytic pathway of pathogenic protozoa. ACTA ACUST UNITED AC 2009; 44:67-124. [PMID: 19410686 DOI: 10.1016/j.proghi.2009.01.001] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Endocytosis is essential for eukaryotic cell survival and has been well characterized in mammal and yeast cells. Among protozoa it is also important for evading from host immune defenses and to support intense proliferation characteristic of some life cycle stages. Here we focused on the contribution of morphological and cytochemical studies to the understanding of endocytosis in Trichomonas, Giardia, Entamoeba, Plasmodium, and trypanosomatids, mainly Trypanosoma cruzi, and also Trypanosoma brucei and Leishmania.
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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, Cidade Universitária, Ilha do Fundão, Rio de Janeiro 21941-902, Brazil.
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13
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Besteiro S, Tonn D, Tetley L, Coombs GH, Mottram JC. The AP3 adaptor is involved in the transport of membrane proteins to acidocalcisomes of Leishmania. J Cell Sci 2008; 121:561-70. [DOI: 10.1242/jcs.022574] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Lysosomal function is crucial for the differentiation and infectivity of the parasitic protozoon Leishmania major. To study lysosomal biogenesis, an L. major mutant deficient in the δ subunit of the adaptor protein 3 (AP3 δ) complex was generated. Structure and proteolytic capacity of the lysosomal compartment were apparently unaffected in the AP3-deficient mutant; however, defects were identified in its acidocalcisomes. These are acidic organelles enriched in calcium and phosphorus, conserved from bacteria to eukaryotes, whose function remains enigmatic. The acidocalcisomes of the L. major mutant lacked membrane-bound proton pumps (notably V-H+-PPase), were less acidic than normal acidocalcisomes and devoid of polyphosphate, but contained a soluble pyrophosphatase. The mutant parasites were viable in vitro, but were unable to establish an infection in mice, which indicates a role for AP3 in determining – possibly through an acidocalcisome-related function – the virulence of the parasite. AP3 transport function has been linked previously to lysosome-related organelles such as platelet dense granules, which appear to share several features with acidocalcisomes. Our findings, implicating that AP3 has a role in transport to acidocalcisomes, thus provide further evidence that biogenesis of acidocalcisomes resembles that of lysosome-related organelles, and that both may have conserved origins.
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Affiliation(s)
- Sébastien Besteiro
- Wellcome Centre for Molecular Parasitology and Division of Infection and Immunity, Institute of Biomedical and Life Sciences, University of Glasgow, 120 University Place, Glasgow, G12 8TA, UK
| | - Daniela Tonn
- Wellcome Centre for Molecular Parasitology and Division of Infection and Immunity, Institute of Biomedical and Life Sciences, University of Glasgow, 120 University Place, Glasgow, G12 8TA, UK
| | - Laurence Tetley
- Wellcome Centre for Molecular Parasitology and Division of Infection and Immunity, Institute of Biomedical and Life Sciences, University of Glasgow, 120 University Place, Glasgow, G12 8TA, UK
| | - Graham H. Coombs
- Wellcome Centre for Molecular Parasitology and Division of Infection and Immunity, Institute of Biomedical and Life Sciences, University of Glasgow, 120 University Place, Glasgow, G12 8TA, UK
| | - Jeremy C. Mottram
- Wellcome Centre for Molecular Parasitology and Division of Infection and Immunity, Institute of Biomedical and Life Sciences, University of Glasgow, 120 University Place, Glasgow, G12 8TA, UK
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Scott DA, Hickerson SM, Vickers TJ, Beverley SM. The role of the mitochondrial glycine cleavage complex in the metabolism and virulence of the protozoan parasite Leishmania major. J Biol Chem 2008; 283:155-165. [PMID: 17981801 PMCID: PMC2963101 DOI: 10.1074/jbc.m708014200] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
For the human pathogen Leishmania major, a key metabolic function is the synthesis of thymidylate, which requires 5,10-methylenetetrahydrofolate (5,10-CH(2)-THF). 5,10-CH(2)-THF can be synthesized from glycine by the mitochondrial glycine cleavage complex (GCC). Bioinformatic analysis revealed the four subunits of the GCC in the L. major genome, and the role of the GCC in parasite metabolism and virulence was assessed through studies of the P subunit (glycine decarboxylase (GCVP)). First, a tagged GCVP protein was expressed and localized to the parasite mitochondrion. Second, a gcvP(-) mutant was generated and shown to lack significant GCC activity using an indirect in vivo assay after incorporation of label from [2-(14)C]glycine into DNA. The gcvP(-) mutant grew poorly in the presence of excess glycine or minimal serine; these studies also established that L. major promastigotes require serine for optimal growth. Although gcvP(-) promastigotes and amastigotes showed normal virulence in macrophage infections in vitro, both forms of the parasite showed substantially delayed replication and lesion pathology in infections of both genetically susceptible or resistant mice. These data suggest that, as the physiology of the infection site changes during the course of infection, so do the metabolic constraints on parasite replication. This conclusion has great significance to the interpretation of metabolic requirements for virulence. Last, these studies call attention in trypanosomatid protozoa to the key metabolic intermediate 5,10-CH(2)-THF, situated at the junction of serine, glycine, and thymidylate metabolism. Notably, genome-based predictions suggest the related parasite Trypanosoma brucei is totally dependent on the GCC for 5,10-CH(2)-THF synthesis.
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Affiliation(s)
- David A Scott
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri 63110
| | - Suzanne M Hickerson
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri 63110
| | - Tim J Vickers
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri 63110
| | - Stephen M Beverley
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri 63110.
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15
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Leishmania mexicana amazonensis: plasma membrane adenine nucleotide translocator and chemotaxis. Exp Parasitol 2007; 118:408-19. [PMID: 18031742 DOI: 10.1016/j.exppara.2007.10.010] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2007] [Revised: 09/26/2007] [Accepted: 10/02/2007] [Indexed: 01/16/2023]
Abstract
Leishmania cannot synthesize purines de novo and rely on their host to furnish these compounds. To accomplish this, they possess multiple purine nucleoside and nucleobase transporters. Subcellular fractionation, immunohistochemical localization with anti-adenine nucleotide translocator (ANT) antibodies and surface biotinylation show that the mitochondrial ANT is also present in the plasma membrane of both promastigotes and amastigotes. Leishmania, however, do not appear to rely on this transporter to supplement their purine or energy requirements via preformed ATP from its host. Rather, Leishmania appear to use the plasma membrane ANT as part of a chemotaxis response. ATP is a chemorepellant for Leishmania and cells treated with atractyloside, an inhibitor of ANT, no longer exhibit negative chemotaxis for this compound.
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16
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Ueda-Nakamura T, Attias M, de Souza W. Comparative analysis of megasomes in members of the Leishmania mexicana complex. Res Microbiol 2007; 158:456-62. [PMID: 17524623 DOI: 10.1016/j.resmic.2007.03.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2005] [Revised: 01/17/2007] [Accepted: 03/21/2007] [Indexed: 11/28/2022]
Abstract
Megasomes are large lysosome-like structures, previously described in amastigote forms of Leishmania belonging to the mexicana complex, whose major constituents are the cysteine proteinases. Routine observation of thin sections of amastigotes obtained from species of the mexicana complex revealed variations in size and number of megasomes according to the species, and also between amastigotes obtained from axenic cultures and from infected animals. Three-dimensional reconstruction of amastigotes, stereology and immunocytochemical localization of cysteine proteinase revealed significant differences between the three Leishmania species examined, L. amazonensis, L. mexicana and L. pifanoi. The relative volume of megasomes in lesion-derived amastigotes was higher than in axenic amastigotes of L. amazonensis and L. mexicana. The relative volume of megasomes from lesion-derived amastigotes of L. mexicana was 2-3 times higher than in L. amazonensis. Axenic amastigotes of L. pifanoi showed a small relative volume of megasomes and low cysteine proteinase activity, and were not able to produce lesions in the animals, whereas axenic amastigotes of L. mexicana and L. amazonensis did. There were significant differences in the structural organization, distribution within the cell, size and number of megasomes, and in the characteristics of cysteine proteinases found in the amastigotes of the three Leishmania species. These results suggest that these organelles and their constituents may be involved in the infectivity and virulence of Leishmania species.
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Affiliation(s)
- Tania Ueda-Nakamura
- Laboratório de Microbiologia, Departamento de Análises Clínicas, Universidade Estadual de Maringá, Av. Colombo, 5790, Bloco I90, 87020-900, Maringá, PR, Brazil.
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17
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Besteiro S, Williams RA, Coombs GH, Mottram JC. Protein turnover and differentiation in Leishmania. Int J Parasitol 2007; 37:1063-75. [PMID: 17493624 PMCID: PMC2244715 DOI: 10.1016/j.ijpara.2007.03.008] [Citation(s) in RCA: 99] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2007] [Accepted: 03/16/2007] [Indexed: 01/15/2023]
Abstract
Leishmania occurs in several developmental forms and thus undergoes complex cell differentiation events during its life-cycle. Those are required to allow the parasite to adapt to the different environmental conditions. The sequencing of the genome of L. major has facilitated the identification of the parasite’s vast arsenal of proteolytic enzymes, a few of which have already been carefully studied and found to be important for the development and virulence of the parasite. This review focuses on these peptidases and their role in the cellular differentiation of Leishmania through their key involvement in a variety of degradative pathways in the lysosomal and autophagy networks.
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Affiliation(s)
- Sébastien Besteiro
- Wellcome Centre for Molecular Parasitology and Division of Infection & Immunity, Institute of Biomedical and Life Sciences, University of Glasgow, 120 University Place, Glasgow G12 8TA, UK
| | - Roderick A.M. Williams
- Wellcome Centre for Molecular Parasitology and Division of Infection & Immunity, Institute of Biomedical and Life Sciences, University of Glasgow, 120 University Place, Glasgow G12 8TA, UK
| | - Graham H. Coombs
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow G4 0NR, UK
| | - Jeremy C. Mottram
- Wellcome Centre for Molecular Parasitology and Division of Infection & Immunity, Institute of Biomedical and Life Sciences, University of Glasgow, 120 University Place, Glasgow G12 8TA, UK
- Corresponding author. Tel.: +44 141 330 3745; fax: +44 141 330 8269.
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18
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Opperdoes FR, Coombs GH. Metabolism of Leishmania: proven and predicted. Trends Parasitol 2007; 23:149-58. [PMID: 17320480 DOI: 10.1016/j.pt.2007.02.004] [Citation(s) in RCA: 141] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2006] [Revised: 01/04/2007] [Accepted: 02/09/2007] [Indexed: 11/16/2022]
Abstract
The complete analysis of the genomes of three major trypanosomatid parasites has facilitated comparison of the metabolic capabilities of each, as predicted from gene sequences. Not surprisingly, there are differences but is it possible to correlate these with the lives of the parasites themselves and make further predictions of the meaning and physiological importance of the apparently parasite-specific metabolism? In this article, we relate gene predictions with the results from experimental studies. We also speculate on the key metabolic adaptations of Leishmania and reasons why it differs from Trypanosoma brucei and Trypanosoma cruzi.
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Affiliation(s)
- Fred R Opperdoes
- Research Unit for Tropical Diseases and Laboratory of Biochemistry, Christian de Duve Institute of Cellular Pathology and Catholic University of Louvain, Avenue Hippocrate 74-75, B-1200 Brussels, Belgium
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19
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Pabón MA, Cáceres AJ, Gualdrón M, Quiñones W, Avilán L, Concepción JL. Purification and characterization of hexokinase from Leishmania mexicana. Parasitol Res 2006; 100:803-10. [PMID: 17061112 DOI: 10.1007/s00436-006-0351-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2006] [Accepted: 09/26/2006] [Indexed: 11/29/2022]
Abstract
Hexokinase from Leishmania mexicana was purified to homogeneity from a glycosome-enriched fraction obtained after a differential centrifugation of promastigote form. The kinetic properties of the pure enzyme were determined and the Km values for glucose (Km = 66 microM) and ATP (Km = 303 muM) were comparable to those from hexokinase of Trypanosoma cruzi. L. mexicana hexokinase was able to use fructose (Km = 142 microM), which reflects the condition found in the insect host. In contrast with hexokinases from other trypanosomatids, the enzyme exhibited a moderate sensitivity to inhibition by glucose 6-phosphate. This inhibition was competitive with respect to both ATP and glucose, indicating that an allosteric site for glucose 6-phosphate does not exist in this enzyme. The enzyme was also inhibited by inorganic pyrophosphate, the inhibition being higher than that observed for T. cruzi enzyme. As expected, the enzyme was localized, by immunofluorescence analysis, in glycosomes and is present in both promastigotes and true amastigotes obtained from hamster lesion. Hexokinase specific activity increased with the aging of promastigote culture, and this increment was related to glucose consumption. However, the level of the hexokinase protein remains constant as determined by Western blotting. Several hypotheses are discussed to explain this result.
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Affiliation(s)
- Miguel A Pabón
- Laboratorio de Enzimología de Parásitos, Centro de Ingeniería Genética, Facultad de Ciencias, Universidad de Los Andes, La Hechicera, Mérida, 5101, Venezuela
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20
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Williams RA, Tetley L, Mottram JC, Coombs GH. Cysteine peptidases CPA and CPB are vital for autophagy and differentiation in Leishmania mexicana. Mol Microbiol 2006; 61:655-74. [PMID: 16803590 DOI: 10.1111/j.1365-2958.2006.05274.x] [Citation(s) in RCA: 116] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In the past, ultrastructural investigations of Leishmania mexicana amastigotes revealed structures that were tentatively identified as autophagosomes. This study has now provided definitive data that autophagy occurs in the parasite during differentiation both to metacyclic promastigotes and to amastigotes, autophagosomes being particularly numerous during metacyclic to amastigote form transformation. Moreover, the results demonstrate that inhibiting two major lysosomal cysteine peptidases (CPA and CPB) or removing their genes not only interferes with the autophagy pathway but also prevents metacyclogenesis and transformation to amastigotes, thus adding support to the hypothesis that autophagy is required for cell differentiation. The study suggests that L. mexicana CPA and CPB perform similar roles to the aspartic peptidase PEP4 and the serine peptidase PRB1 in Saccharomyces cerevisiae. The results also provide an explanation for why L. mexicana CPA/CPB-deficient mutants transform to amastigotes very poorly and lack virulence in macrophages and mice.
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Affiliation(s)
- Roderick A Williams
- Division of Infection and Immunity, Institute of Biomedical and Life Sciences and Wellcome Centre for Molecular Parasitology, Glasgow Biomedical Research Centre, University of Glasgow, Glasgow G12 8TA, UK
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21
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Al-Mulla Hummadi YM, Al-Bashir NM, Najim RA. Leishmania major and Leishmania tropica: II. Effect of an immunomodulator, S(2) complex on the enzymes of the parasites. Exp Parasitol 2005; 112:85-91. [PMID: 16274690 DOI: 10.1016/j.exppara.2005.09.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2005] [Revised: 09/21/2005] [Accepted: 09/21/2005] [Indexed: 11/19/2022]
Abstract
S(2) complex has been reported to have a direct antileishmanial effect. The possibility that the direct antileishmanial effect may be due to inhibition of key enzymes involved in glucose metabolism and/ or enzymes associated with virulence was investigated. Cell pellets were prepared from cultures of both axenic amastigotes and promastigotes of Leishmania major (MHOM/IQ/93/MRC6) and L. tropica (MHOM/IQ/93/MRC2). S(2) complex, at various concentrations, was added to the enzyme extracts prepared from the pellets. Results show that in the Embden-Meyerhof pathway, both hexokinase and glucose-phosphate isomerase but not fructophosphokinase were dose dependently inhibited. In the hexose-monophosphate shunt both glucose-6-phosphate dehydrogenase and ribose-5-phosphate isomerase were dose dependently inhibited. Malic dehydrogenase and malic enzyme from the citric-acid cycle were both dose dependently inhibited but succinate dehydrogenase from the same pathway was not inhibited. Both enzymes associated with virulence (protease and acid phosphatase), showed activation rather than inhibition at higher doses of S(2) complex. Thus, the direct antileishmanial effect of S(2) complex may result, partially or entirely, from the inhibition of enzymes that are necessary for the parasites' carbohydrate metabolism.
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Affiliation(s)
- Yassir M Al-Mulla Hummadi
- Department of Pharmacology, College of Medicine, University of Baghdad, P.O. Box 61208, Baghdad 12114, Iraq
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22
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Corrêa JR, Santos SG, Araújo MS, Baptista C, Soares MJ, Brazil RP. Axenic promastigote forms of Leishmania (Viannia) lainsoni as an alternative source for Leishmania antigen production. J Parasitol 2005; 91:551-6. [PMID: 16108545 DOI: 10.1645/ge-396r1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
The present study demonstrates that axenic cultures of Leishmania (Viannia) lainsoni produce larger cell masses in NNN-LIT medium, as well as higher amounts of total proteins in cell extracts, than Leishmania (Leishmania) amazonensis. Antigenicity of L. (V.) lainsoni whole promastigotes is similar to that of L. (L.) amazonensis, as demonstrated by an indirect immunofluorescence diagnostic test using sera from human patients and dogs infected with visceral leishmaniasis. Infectivity of the L. (V.) lainsoni strain used in the present work was demonstrated by the detection by transmission-electron microscopy of tissue amastigotes in skin lesion samples from an experimentally infected hamster. Incubation of lesion fragments in NNN-LIT medium allowed us to obtain promastigote forms, which could be cultivated successfully in vitro. lsoenzyme analysis of such promastigotes confirmed the parasite strain as L. (V.) lainsoni, as compared to other Leishmania reference strains. Our data indicate that L. (V.) lainsoni is a useful alternative source for antigen production as well for use in assays that depend on large cell volumes of Leishmania spp. parasites.
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Affiliation(s)
- José R Corrêa
- Lab. Biologia Celular de Microrganismos, Departamento de Ultra-estrutura e Biologia Celular, Instituto Oswaldo Cruz/FIOCRUZ, Av. Brasil 4365, 21040-900 Rio de Janeiro, RJ, Brazil.
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23
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Abstract
Amino acid and dipeptide esters kill intracellular and isolated L. amazonensis amastigotes. Several o f the compounds also restrict the growth o f mouse lesions after intralesional administration. However, the esters are known to be toxic in vitro for monocytes and certain lymphoid cells. Michel Rabinovitch surveys the mechanisms o f the leishmanicidal activity, describes some structure--activity relationships, and discusses strategies for the design of compounds more selective for the parasite.
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Affiliation(s)
- M Rabinovitch
- Michel Rabinovitch is at the Unité d'Immunoparositologie, Institut Pasteur, 25 rue du Docteur Roux, 75724 Paris, France
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24
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Huynh C, Andrews NW. Leishmania amazonensis Rab7 promotes toxicity of the amino acid ester Leu-OMe in amastigote megasomes. Mol Biochem Parasitol 2004; 132:101-4. [PMID: 14599671 DOI: 10.1016/j.molbiopara.2003.08.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Chau Huynh
- Section of Microbial Pathogenesis, Boyer Center for Molecular Medicine, Yale University School of Medicine, 295 Congress Avenue, New Haven, CT 06536, USA
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25
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Pral EMF, da Moitinho MLR, Balanco JMF, Teixeira VR, Milder RV, Alfieri SC. Growth phase and medium ph modulate the expression of proteinase activities and the development of megasomes in axenically cultivated Leishmania (Leishmania) amazonensis amastigote-like organisms. J Parasitol 2003; 89:35-43. [PMID: 12659300 DOI: 10.1645/0022-3395(2003)089[0035:gpampm]2.0.co;2] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Leishmania (Leishmania) amazonensis LV79 (MPRO/BR/72/M1841) has been adapted to grow at 33 C as amastigote-like (AL) organisms in modified UM-54 medium initially adjusted to a pH of 4.8-5.0. Axenic cultures could be routinely restarted from parasites recovered from footpad lesions obtained by inoculation of BALB/c mice with preadapted culture stages. Morphological features, proteinase activities, and infectivity of AL organisms were examined during the in vitro growth cycle, and differences were found between log- and stationary-phase parasites. Stationary-phase AL organisms were morphologically similar to lesion amastigotes, did not react with a paraflagellar rod-specific monoclonal antibody in western blots, and contained proteinase activities resolving identically to the enzymes of lesion amastigotes in gelatin gels. Whereas typical megasomes could be identified in about a third of the stationary-phase AL population, the organelles were rarely seen in log-phase organisms. Azocaseinolytic activity progressively increased during the exponential growth phase and reached its highest values (approximately 65-70% of those determined in lesion amastigotes) at the stationary phase; the association of total proteinase activity with increased expression of cysteine proteinases was indicated by the strong inhibition of azocasein hydrolysis by E-64, the intensified banding of the 28-, 31-, and 35-kDa proteinases in gelatin gels, and the higher susceptibility of stationary-phase AL organisms to L-leucine methyl ester. Although overall axenic amastigotes were less infective to BALB/c mice than were lesion-derived parasites, stationary-phase AL organisms were more infective than were log-phase parasites. Medium pH increased during the exponential growth phase, but dropped in the stationary phase, when the observed morphological, biochemical, and biological changes became apparent.
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Affiliation(s)
- Elizabeth M F Pral
- Departamento de Parasitologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, Av. Prof. Lineu Prestes 1374, CEP 05508-900, São Paulo, S. P., Brazil
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26
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Waller RF, McConville MJ. Developmental changes in lysosome morphology and function Leishmania parasites. Int J Parasitol 2002; 32:1435-45. [PMID: 12392909 DOI: 10.1016/s0020-7519(02)00140-6] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The endocytic pathway of Leishmania parasites has recently come under intense research focus through the development of several markers for various compartments of this pathway. Through these studies a novel multivesicular tubule lysosome has been discovered in promastigote-stage parasites. This organelle has a highly dynamic role during parasite growth and differentiation. This review discusses recent insights into the Leishmania lysosome with respect to its organisation within the endocytic pathway, stage-specific functions, and biogenesis.
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Affiliation(s)
- Ross F Waller
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, Vic 3010, Australia
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27
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McConville MJ, Mullin KA, Ilgoutz SC, Teasdale RD. Secretory pathway of trypanosomatid parasites. Microbiol Mol Biol Rev 2002; 66:122-54; table of contents. [PMID: 11875130 PMCID: PMC120783 DOI: 10.1128/mmbr.66.1.122-154.2002] [Citation(s) in RCA: 175] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The Trypanosomatidae comprise a large group of parasitic protozoa, some of which cause important diseases in humans. These include Trypanosoma brucei (the causative agent of African sleeping sickness and nagana in cattle), Trypanosoma cruzi (the causative agent of Chagas' disease in Central and South America), and Leishmania spp. (the causative agent of visceral and [muco]cutaneous leishmaniasis throughout the tropics and subtropics). The cell surfaces of these parasites are covered in complex protein- or carbohydrate-rich coats that are required for parasite survival and infectivity in their respective insect vectors and mammalian hosts. These molecules are assembled in the secretory pathway. Recent advances in the genetic manipulation of these parasites as well as progress with the parasite genome projects has greatly advanced our understanding of processes that underlie secretory transport in trypanosomatids. This article provides an overview of the organization of the trypanosomatid secretory pathway and connections that exist with endocytic organelles and multiple lytic and storage vacuoles. A number of the molecular components that are required for vesicular transport have been identified, as have some of the sorting signals that direct proteins to the cell surface or organelles in the endosome-vacuole system. Finally, the subcellular organization of the major glycosylation pathways in these parasites is reviewed. Studies on these highly divergent eukaryotes provide important insights into the molecular processes underlying secretory transport that arose very early in eukaryotic evolution. They also reveal unusual or novel aspects of secretory transport and protein glycosylation that may be exploited in developing new antiparasite drugs.
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Affiliation(s)
- Malcolm J McConville
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, Victoria 3010, Australia.
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28
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Sereno D, Guilvard E, Maquaire S, Cavaleyra M, Holzmuller P, Ouaissi A, Lemesre JL. Experimental studies on the evolution of antimony-resistant phenotype during the in vitro life cycle of Leishmania infantum: implications for the spread of chemoresistance in endemic areas. Acta Trop 2001; 80:195-205. [PMID: 11700176 DOI: 10.1016/s0001-706x(01)00154-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Pentavalent antimonial unresponsiveness is an emerging problem in endemic areas and information on factors which could modulate the transmission of drug-resistant phenotypes and parasites during life cycle are warranted. Using axenic amastigotes resistant to potassium antimonyl tartrate (Sb(III)) we investigated the modulation of antimonyl resistance during the in vitro life cycle. We assessed: (i) the stability of the drug-resistant phenotype during the in vitro life cycle; (ii) the transmission of drug-resistant clones when mixed with a wild-type clone at different susceptible/chemoresistant ratios (50/50,90/10,10/90) after one or two in vitro life cycles. We demonstrate that: (i) mutants which were 12,28,35 and 44 fold more resistant to Sb(III)-antimonial than their parental wild-type, were Glucantime Sb(V)-resistant when growing in THP-1 cells; (ii) the drug-resistant phenotype was partially retained during long-term in vitro culture (3 months) in drug free medium; (iii) the antimonyl-resistant phenotype was retained after one or more in vitro life cycles. However, when drug-resistant parasites were mixed with susceptible, mutants could not be detected in the resulting population, after one or two in vitro life cycles, whatever the initial wild-type/chemoresistant ratio. These results could be explained by the lower capacity of drug-resistant amastigotes to undergo the amastigote-promastigote differentiation process, leading probably to their sequential elimination during life cycle. Taken together, these observations demonstrate that different factors could modulate the transmission of Leishmania drug resistance during the parasite's life cycle.
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Affiliation(s)
- D Sereno
- UR 008 "Pathogénie des Trypanosomatidae" Centre Institut de Recherche pour le Devéloppement (IRD), 911 Ave. Agropolis, BP 5045, 34032 Montpellier cédex 1, France
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29
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Ghedin E, Debrabant A, Engel JC, Dwyer DM. Secretory and endocytic pathways converge in a dynamic endosomal system in a primitive protozoan. Traffic 2001; 2:175-88. [PMID: 11260523 DOI: 10.1034/j.1600-0854.2001.020304.x] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Leishmania are a group of primitive eukaryotic trypanosomatid protozoa that are apically polarized with a flagellum at their anterior end. Surrounding the base of the flagellum is the flagellar reservoir that constitutes the site for endocytosis and exocytosis in these organisms. In the present study, we define a novel multivesicular tubular compartment involved in the intracellular trafficking of macromolecules in Leishmania. This dynamic structure appears to subtend the flagellar reservoir and extends towards the posterior end of the cell. Functional domains of several surface-expressed proteins, such as the gp63 glycosyl phosphatidyl inositol anchor and the 3'nucleotidase/nuclease transmembrane domain were fused to green fluorescent protein. These chimeric proteins were found to traffic through the secretory pathway and, while reaching their intended destinations, also accumulated within the intracellular tubular compartment. Using various compounds that are efficient fluid-phase markers used to track endocytosis in higher eukaryotes, we showed that this tubular compartment constitutes an important station in the endocytic pathway of these cells. Based on our functional observations of its role in the trafficking of expressed proteins and endocytosed markers, this compartment appears to have properties similar to endosomes of higher eukaryotes.
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Affiliation(s)
- E Ghedin
- Cell Biology Section, Laboratory of Parasitic Diseases, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892-0425, USA
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30
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Cooper K, Gupta A, Beaudoin S. Simulation of the Adhesion of Particles to Surfaces. J Colloid Interface Sci 2001; 234:284-292. [PMID: 11161514 DOI: 10.1006/jcis.2000.7276] [Citation(s) in RCA: 136] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The removal of micrometer and submicrometer particles from dielectric and metal films represents a challenge in postchemical mechanical polishing cleaning. Proper modeling of the adhesive force between contaminant particles and these films is needed to develop optimal solutions to postchemical mechanical polishing cleaning. We have previously developed and experimentally validated a model to describe the adhesion between spherical particles and thin films. This simulation expands previous models to characterize the adhesive interaction between asymmetrical particles, characteristic of a polishing slurry, and various films. Our simulation accounts for the contact area between particles and substrates, as well as the morphology of the surfaces. Previous models fail to accurately describe the contact of asymmetrical particles interacting with surfaces. By properly accounting for nonideal and geometry and morphology, the simulation predicts a more accurate adhesive force than predictions based upon an ideal van der Waals model. The simulation is compared to experimental data taken for both semi-ideal particle-substrate systems (polystyrene latex spheres in contact with silicon films) and asymmetrical systems (alumina particles in contact with various films). Copyright 2001 Academic Press.
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Affiliation(s)
- Kevin Cooper
- Department of Chemical and Materials Engineering, Arizona State University, Tempe, Arizona, 85287
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31
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Sereno D, Holzmuller P, Lemesre JL. Efficacy of second line drugs on antimonyl-resistant amastigotes of Leishmania infantum. Acta Trop 2000; 74:25-31. [PMID: 10643904 DOI: 10.1016/s0001-706x(99)00048-0] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
In a previous paper we have demonstrated that the induction, by direct drug pressure, of a resistance to Sb(III) antimony at physiological concentration in the amastigote stage of the parasite, led to a high cross-resistance to Sb(V) species in the form of Glucantime. In this paper, further chemoresistant clones were characterized. Axenic amastigotes of Leishmania infantum were adapted to survive in culture medium containing 4, 20, 30 and 120 microg/ml of potassium antimonyl tartrate Sb(II). These mutants were 12, 28, 35 and 44-fold more resistant to Sb(III) than the parental wild-type clone. They were able to resist at concentrations of Glucantime Sb(V) as high as 160 microg/ml when growing in THP-1 cells. We have investigated the efficacy of second line drugs in clinical use (pentamidine and amphotericin B) on the antimony-resistant mutants. Amphotericin B was toxic for both wild-type and chemoresistant mutants at concentrations ranging from 0.05 to 0.15 microM. Pentamidine which is extensively used when the first course of antimonial pentavalent compounds is unsuccessful, was more toxic for all the chemoresistant organisms than for the wild-type clone. In the same way, chemoresistant amastigotes growing within THP-1 cells were more susceptible to pentamidine than the wild-type clone. Our results showed that the resistance of the mutants was restricted to the antimony containing drugs and did not led to a cross-resistance against the other clinically relevant drugs. These results confirmed that these two drugs (pentamidine and amphotericin B) are good candidates to treat pentavalent antimonial unresponsiveness.
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Affiliation(s)
- D Sereno
- Laboratoire de Biologie Parasitaire, Institut de Recherche pour le Développement, Montpellier, France
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32
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Sereno D, Cavaleyra M, Zemzoumi K, Maquaire S, Ouaissi A, Lemesre JL. Axenically grown amastigotes of Leishmania infantum used as an in vitro model to investigate the pentavalent antimony mode of action. Antimicrob Agents Chemother 1998; 42:3097-102. [PMID: 9835497 PMCID: PMC106005 DOI: 10.1128/aac.42.12.3097] [Citation(s) in RCA: 108] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The mechanism(s) of activity of pentavalent antimony [Sb(V)] is poorly understood. In a recent study, we have shown that potassium antimonyl tartrate, a trivalent antimonial [Sb(III)], was substantially more potent than Sb(V) against both promastigotes and axenically grown amastigotes of three Leishmania species, supporting the idea of an in vivo metabolic conversion of Sb(V) into Sb(III). We report that amastigotes of Leishmania infantum cultured under axenic conditions were poorly susceptible to meglumine [Glucantime; an Sb(V)], unlike those growing inside THP-1 cells (50% inhibitory concentrations [IC50s], about 1.8 mg/ml and 22 microg/ml, respectively). In order to define more precisely the mode of action of Sb(V) agents in vivo, we first induced in vitro Sb(III) resistance by direct drug pressure on axenically grown amastigotes of L. infantum. Then we determined the susceptibilities of both extracellular and intracellular chemoresistant amastigotes to the Sb(V)-containing drugs meglumine and sodium stibogluconate plus m-chlorocresol (Pentostam). The chemoresistant amastigotes LdiR2, LdiR10, and LdiR20 were 14, 26, and 32 times more resistant to Sb(III), respectively, than the wild-type one (LdiWT). In accordance with the hypothesis described above, we found that intracellular chemoresistant amastigotes were resistant to meglumine [Sb(V)] in proportion to the initial level of Sb(III)-induced resistance. By contrast, Sb(III)-resistant cells were very susceptible to sodium stibogluconate. This lack of cross-resistance is probably due to the presence in this reagent of m-chlorocresol, which we found to be more toxic than Sb(III) to L. infantum amastigotes (IC50s, of 0.54 and 1.32 microg/ml, respectively). Collectively, these results were consistent with the hypothesis of an intramacrophagic metabolic conversion of Sb(V) into trivalent compounds, which in turn became readily toxic to the Leishmania amastigote stage.
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Affiliation(s)
- D Sereno
- Laboratoire de Biologie Parasitaire, Centre ORSTOM, 34 032 Montpellier Cedex 1, France
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33
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Sereno D, Lemesre JL. In vitro life cycle of pentamidine-resistant amastigotes: stability of the chemoresistant phenotypes is dependent on the level of resistance induced. Antimicrob Agents Chemother 1997; 41:1898-903. [PMID: 9303381 PMCID: PMC164032 DOI: 10.1128/aac.41.9.1898] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Using a continuous drug pressure protocol, we induced pentamidine resistance in an active and dividing population of amastigote forms of Leishmania mexicana. We selected in vitro two clones with different levels of resistance to pentamidine, with clone LmPENT5 being resistant to 5 microM pentamidine, while clone LmPENT20 was resistant to 20 microM pentamidine. Resistance indexes (50% inhibitory concentration [IC50] after drug presure/IC50 before drug pressure) of 2 (LmPENT5) and 6 (LmPENT20) were determined after drug selection. Both resistant clones expressed significant cross-resistance to diminazene aceturate and primaquine. Pentamidine resistance was not reversed by verapamil, a calcium channel blocker known to reverse multidrug resistance (A. J. Bitonti, et al., Science 242:1301-1303, 1988; A. R. C. Safa et al., J. Biol. Chem. 262:7884-7888, 1987). No difference in the in vitro infectivity for resident mouse macrophages was observed between the wild-type clone (clone LmWT) and pentamidine-resistant clones. During in vitro infectivity experiments, when the life cycle was performed starting from the intramacrophagic amastigote stage, the drug resistance of the resulting LmPENT20 amastigotes was preserved even if the intermediate promastigote stage could not be considered resistant to 20 microM pentamidine. In the same way, when a complete developmental sequence of L. mexicana was achieved axenically by manipulation of appropriate culture conditions, the resulting axenically grown LmPENT20 amastigotes remained pentamidine resistant, whereas LmPENT5 amastigotes lost their ability to resist pentamidine, with IC50s and index of resistance values close to those for the LmWT clone. These results strongly indicate that the level of pentamidine tolerated by resistant amastigotes after the life cycle was dependent on the induced level of resistance. This fact could be significant in the in vivo transmission of drug-resistant parasites by Phlebotominae. Particular attention should be given to the finding that the emergence of parasite resistance is a potential risk of the use of inadequate doses as therapy in humans.
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Affiliation(s)
- D Sereno
- Laboratoire d'Epidémiologie des Maladies à Vecteur, Unité de Biologie Parasitaire, ORSTOM, Montpellier, France
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34
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Three-dimensional reconstruction of glycosomes in trypanosomatids of the genus Phytomonas. Tissue Cell 1995; 27:39-45. [DOI: 10.1016/s0040-8166(95)80007-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/1994] [Accepted: 08/25/1994] [Indexed: 11/23/2022]
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35
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Bijovsky AT. Leishmania mexicana: the influence of slightly elevated temperature on the ultrastructure of axenic amastigote-like forms. Parasitol Res 1994; 80:696-8. [PMID: 7886041 DOI: 10.1007/bf00932956] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- A T Bijovsky
- Departamento de Parasitologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, Brasil
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36
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Yahiaoui B, Loyens M, Taibi A, Schöneck R, Dubremetz JF, Ouaissi MA. Characterization of a Leishmania antigen associated with cytoplasmic vesicles resembling endosomal-like structure. Parasitology 1993; 107 ( Pt 5):497-507. [PMID: 8295789 DOI: 10.1017/s0031182000068074] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
In the present study we have used antibodies to Leishmania major promastigote antigens which were eluted from a glutathione-agarose column (LmGbp) and could identify several parasite components among different Leishmania species by using immunoprecipitation and Western blot techniques. The results also showed that some of LmGbp are present among the molecules released into the culture medium. Moreover, immunofluorescence assays clearly demonstrated that LmGbp are expressed by intracellular amastigotes. The electron micrographs of thawed cryosections of L. major-infected cells revealed that the antigens were associated with the membrane of the phagocytic vacuole. Moreover, the Western blot technique allowed us to identify, using other Leishmania species extracts and anti-LmGbp antibodies, a major polypeptide of an apparent molecular mass of 66 kDa. Immunofluorescence studies suggested that the 66 kDa polypeptide is associated with intracytoplasmic vesicles. Cryosections of Leishmania promastigotes improved the fine structure preservation of the organelles and enabled a number of features to be seen, particularly the structures considered as vesicles, which appeared as a complex tubulo-vesicular structure resembling mammalian cell endosomes and Leishmania organelles previously named 'megasomes'. Further studies using antibodies against the native 66 kDa protein will be needed to investigate the localization of the protein at the ultrastructural level and to follow its intracellular vesicular traffic.
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Affiliation(s)
- B Yahiaoui
- Research Laboratory on Trypanosomatids, INSERM U 167, Institut Pasteur, Lille, France
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37
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Abstract
The surface of the trypanosomatid forms the interface between the parasite and its host, and has evolved to repel a variety of host anti-microbial defences. The flagellar pocket constitutes a highly differentiated region of the trypanosomatid surface that facilitates internalization of host macromolecules, while restricting host access to the exposed, endocytic receptors of the parasite. In this review, Paul Webster and David Russell discuss the ability of this organelle to accumulate efficiently nutrients obtained from the host as a major factor in the success of this group of parasites.
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Affiliation(s)
- P Webster
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06510, USA
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38
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Pan AA, Duboise SM, Eperon S, Rivas L, Hodgkinson V, Traub-Cseko Y, McMahon-Pratt D. Developmental life cycle of Leishmania--cultivation and characterization of cultured extracellular amastigotes. J Eukaryot Microbiol 1993; 40:213-23. [PMID: 8461895 DOI: 10.1111/j.1550-7408.1993.tb04906.x] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The biochemistry and immunology of Leishmania promastigotes has been extensively studied; this is due primarily to the facility with which this stage, in contrast to the amastigotes stage, can be maintained in axenic culture. Several attempts to axenically culture lines of Leishmania amastigotes have been reported in the literature. This paper summarizes methods of adaptation (low pH, elevated temperature and culture medium) and characterization of several axenic lines of Leishmania amastigotes. Based on morphological, biological, immunological and biochemical evidence, these organisms appear to resemble amastigotes from infected macrophages or tissue. The axenically cultured amastigotes appear to be distinct from shocked (heat, serum deprivation, stressed) Leishmania promastigotes in the plethora of proteins synthesized, growth (multiplication) in culture, and developmental regulation observed. These data suggest that Leishmania organisms have a significant developmental response to certain signals (pH, temperature) mimicking their in vivo macrophage milieu. The response to other environmental parameters characteristic of the host-macrophage remain to be determined. These axenically cultured amastigotes should be of interest for further immunological, biochemical and developmental investigations of the disease-maintaining stage of this parasite.
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Affiliation(s)
- A A Pan
- Yale University School of Medicine, Department of Epidemiology and Public Health, New Haven, Connecticut 06510
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39
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Russell DG, Xu S, Chakraborty P. Intracellular trafficking and the parasitophorous vacuole of Leishmania mexicana-infected macrophages. J Cell Sci 1992; 103 ( Pt 4):1193-210. [PMID: 1487496 DOI: 10.1242/jcs.103.4.1193] [Citation(s) in RCA: 130] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The continued success of Leishmania as an intramacrophage parasite is dependent on its ability to survive within an acidic intracellular compartment, resist degradation by lysosomal hydrolases, exploit the host cell as a source of nutrients, and avoid the macrophage's antigen-presenting capabilities. All these requirements are dependent on the properties of the parasitophorous vacuole in which Leishmania resides. This study shows that the vacuole possesses membrane proteins characteristic of a lysosome, and has MHC class II molecules. The trafficking of a variety of endocytic markers supports this finding. However, a temporal study up to 14 days post-infection indicates that, as it matures, the vacuole gains mannose 6-phosphate receptor, and becomes more accessible to endocytosed ligand, suggesting that the vacuole has functionally translocated from a lysosomal to late endosomal compartment. Endocytosed material was detected in the flagellar pocket and inside the amastigote, demonstrating parasite uptake of intra-vacuolar material. Careful analysis of amastigotes suggests that they avoid antigen presentation by their host cell by limiting the release of potential antigens. These findings significantly extend our understanding of the mechanisms employed by Leishmania to ensure its survival in the macrophage.
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Affiliation(s)
- D G Russell
- Department of Molecular Microbiology, Washington University Medical School, St. Louis, MO 63110
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40
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Bates PA, Robertson CD, Tetley L, Coombs GH. Axenic cultivation and characterization of Leishmania mexicana amastigote-like forms. Parasitology 1992; 105 ( Pt 2):193-202. [PMID: 1454417 DOI: 10.1017/s0031182000074102] [Citation(s) in RCA: 155] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
A new method is described which has made possible the long-term axenic cultivation of Leishmania mexicana amastigote-like forms in Schneider's Drosophila medium supplemented with 20% (v/v) foetal calf serum. Unlike previous methods, it utilizes direct culture of parasites obtained from the lesions of infected animals rather than adaptation of promastigotes in vitro. Ultrastructural (possession of megasomes), biochemical (cysteine proteinase activity and gelatin SDS-PAGE banding pattern) and infectivity (in vivo) data are presented which show the close similarity of the cultured forms to lesion amastigotes. The axenically cultured forms grew optimally at a temperature of 32-33 degrees C, providing further evidence for their amastigote nature. It was found that adjustment of the pH of the growth medium to 5.4 was required in order to retain the amastigote morphology of the cultured parasites. This supports the notion that leishmanial amastigotes are acidophiles.
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Affiliation(s)
- P A Bates
- Department of Zoology, University of Glasgow
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41
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Rainey PM, Spithill TW, McMahon-Pratt D, Pan AA. Biochemical and molecular characterization of Leishmania pifanoi amastigotes in continuous axenic culture. Mol Biochem Parasitol 1991; 49:111-8. [PMID: 1775152 DOI: 10.1016/0166-6851(91)90134-r] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Inability to culture the disease-producing amastigote form of Leishmania has greatly hampered its study. We have biochemically characterized an axenically cultured amastigote-like form of Leishmania pifanoi. This form closely resembles amastigotes in proteinase, ribonuclease, adenine deaminase and peroxidase activity. It also exhibits comparable rates of growth, transformation, synthesis of DNA, RNA and protein, and metabolism of glucose and linoleic acid. It is distinct from promastigotes in these characteristics. The expression of the genes for beta-tubulin and the P100/11E reductase is developmentally regulated in this axenic form as in amastigotes. These results, combined with previous demonstrations of amastigote morphology and antigenicity in the culture form, confirm that Leishmania amastigotes have been successfully propagated in axenic media. This strain should serve as an excellent model for the study of amastigote biochemistry, pharmacology and immunology, and the molecular genetics of the transformation between amastigote and promastigote forms.
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Affiliation(s)
- P M Rainey
- Department of Laboratory Medicine, Yale University School of Medicine, New Haven, CT
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42
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Tetley L, Vickerman K. The glycosomes of trypanosomes: number and distribution as revealed by electron spectroscopic imaging and 3-D reconstruction. J Microsc 1991; 162:83-90. [PMID: 1870115 DOI: 10.1111/j.1365-2818.1991.tb03118.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Computer-aided 3-D reconstruction of trypanosomes from 0.35-micron-thick sections imaged on the Zeiss 902 electron microscope are being used to study the dynamics of cell organization. Segregation of glycolytic enzymes into glycosomes raises questions concerning the distribution and biogenesis of these organelles. Direct counts of glycosomes from Trypanosoma evansi indicate 30-40 per cell and for the closely related T. brucei, 65 per cell. These figures contrast with the estimates of others who have used model-based morphometric methods to obtain a value of 230 per cell.
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Affiliation(s)
- L Tetley
- Department of Zoology, University of Glasgow, U.K
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43
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Galvao-Quintao L, Alfieri SC, Ryter A, Rabinovitch M. Intracellular differentiation of Leishmania amazonensis promastigotes to amastigotes: presence of megasomes, cysteine proteinase activity and susceptibility to leucine-methyl ester. Parasitology 1990; 101 Pt 1:7-13. [PMID: 2235078 DOI: 10.1017/s0031182000079683] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Intracellular differentiation of Leishmania promastigotes to amastigotes is a critical step in the establishment of infection. In this report three related features of mexicana subspecies amastigotes were used to follow the differentiation of the parasites within macrophages. Early after infection, (a) parasites did not contain ultrastructurally recognizable megasomes, (b) cysteine proteinase activity of parasite lysates was not detected in gelatin-containing acrylamide gels, and (c) parasites were essentially resistant to L-leucine-methyl ester (Leu-OMe). Typical megasomes were first identified on the 5th day, were more prevalent on day 7, and underwent swelling in macrophages exposed to Leu-OMe. Cysteine proteinase activity was first detected on day 3 and increased thereafter. Susceptibility to Leu-OMe of parasites studied in situ or isolated from infected macrophages increased with time of intracellular residence and by 7 days approached that of amastigotes isolated from mouse lesions. In contrast, parasites derived from either promastigotes or amastigotes were equally susceptible to another leishmanicidal compound, tryptophanamide (Trp-NH2). The results provide additional support for the involvement of megasomes and their cysteine proteinases in parasite killing by Leu-OMe, and highlight the slow pace of the intracellular differentiation of L. amazonensis promastigotes to amastigotes.
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Affiliation(s)
- L Galvao-Quintao
- Unité d'Immunoparasitologie, Institut Pasteur et CNRS (URA 361), Paris, France
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44
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Antoine JC, Jouanne C, Ryter A. Megasomes as the targets of leucine methyl ester in Leishmania amazonensis amastigotes. Parasitology 1989; 99 Pt 1:1-9. [PMID: 2797865 DOI: 10.1017/s0031182000060960] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Certain L-amino acid esters, such as L-leucine methyl ester (Leu-OMe), can kill intracellular and isolated Leishmania amazonensis amastigotes. Killing appears to involve ester trapping and hydrolysis within an acidified parasite compartment (M. Rabinovitch and S. C. Alfieri, 1987, Brazilian Journal of Medical and Biological Research 20, 665-74). We show here by acid phosphatase light microscopic cytochemistry and by ultrastructural morphometry that megasomes, lysosome-like amastigote organelles, are the putative parasite targets of Leu-OMe. This conclusion is supported by the following observations. (a) Control amastigotes displayed a string of electron-dense, acid phosphatase-positive megasomes mostly located in the cellular poles opposite the flagellar pockets. Incubation of the amastigotes with Leu-OMe resulted in concentration-dependent swelling and fusion of the organelles as well as decreased electron density of the internal contents. These changes, which preceded parasite disruption, were followed by the progressive loss of parasite viability and the release of acid phosphatase activity into the medium. (b) Incubation of the amastigotes with L-isoleucine methyl ester, a non-leishmanicidal compound, induced only moderate fusion of the megasomes. (c) Pre-incubation of the parasites with the proteinase inhibitors antipain and chymostatin, previously shown to confer protection from Leu-OMe toxicity, nearly completely prevented the morphological changes of megasomes. (d) Exposure of amastigotes to tryptophanamide (Trp-NH2), the leishmanicidal activity of which is not reduced by antipain and chymostatin, did not result in swelling and fusion of the megasomes. This last finding suggests that different mechanisms underlie the destruction of amastigotes by Trp-NH2 and Leu-OMe.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- J C Antoine
- Unité d' Immunophysiologie cellulaire de l'Institut Pasteur et du C.N.R.S. (UA 1113), Département de Physiopathologie expérimentale, Paris, France
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Alfieri SC, Shaw E, Zilberfarb V, Rabinovitch M. Leishmania amazonensis: involvement of cysteine proteinases in the killing of isolated amastigotes by L-leucine methyl ester. Exp Parasitol 1989; 68:423-31. [PMID: 2721634 DOI: 10.1016/0014-4894(89)90127-6] [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
L-leucine-methyl ester (Leu-OMe) kills Leishmania mexicana amazonensis amastigotes by a mechanism which requires proteolytic cleavage of the ester. N-Benzyloxycarbonyl-phenylalanyl-alanyl diazomethane (Z-Phe-AlaCHN2), a specific and irreversible inhibitor of cysteine proteinases, was used to characterize the enzymes involved in parasite destruction. It was shown that (1) amastigotes preincubated with micromolar concentrations of Z-Phe-AlaCHN2 survived challenge with Leu-OMe concentrations lethal to control parasites; (2) the proteolytic activity of 25- to 33-kDa cysteine proteinases in parasite lysates subjected to electrophoresis in gelatin-containing acrylamide gels was selectively inhibited in parasites pretreated with Z-Phe-AlaCHN2 and chased in inhibitor-free medium; and (3) cysteine proteinase activity was also inhibited in gels incubated with amino acid and dipeptide esters, possibly because the compounds were acting either as substrates (e.g., Leu-Leu-OMe) or as inhibitors (e.g., Ile-OMe) of the enzyme. The results support the involvement of low molecular weight cysteine proteinases in the destruction of amastigotes by Leu-OMe. Characterization of the structure and substrate specificity of the enzymes may permit the rational development of more selectively leishmanicidal amino acid derivatives.
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Antoine JC, Jouanne C, Ryter A, Benichou JC. Leishmania amazonensis: acidic organelles in amastigotes. Exp Parasitol 1988; 67:287-300. [PMID: 3056736 DOI: 10.1016/0014-4894(88)90076-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Leishmania amastigotes are intracellular protozoan parasites which exclusively invade cells of the macrophage series and multiply within phagolysosomes. Recent studies showed that intracellular and isolated amastigotes of L. amazonesis are killed by amino acid esters which appear to be trapped within as yet unidentified, possibly acidified, "lysosome-like" parasite compartments and cleaved by hydrolytic enzyme(s) (M. Rabinovitch, V. Zilberfarb, and C. Ramazeilles, 1986, Journal of Experimental Medicine 163, 520-535). In the present study, we have localized acidic compartments of Leishmania amastigotes using as a probe the weak base 3-(2,4 dinitroanilino)-3'-amino-N-methyldipropylamine (DAMP). This indicator, which can be detected within cells by light and electron microscopy using immunocytochemical immunocytochemical methods, mainly accumulates within megasomes and in dense inclusion vacuoles. With the help of quantitative assays to titrate cell-associated DAMP, it was found that (a) its uptake is temperature dependent and thus probably requires an energy supply, (b) the proton ionophore monensin partially inhibits the trapping of DAMP, and (c) monensin greatly increases its efflux from cells. These results, as well as those obtained by quantitative ultrastructural immunocytochemistry of cells incubated with DAMP in the absence or presence of monensin, show that megasomes and inclusion vacuoles have a low pH probably maintained by an active process. Furthermore, confirming the report of H. F. Hassan and G. H. Coombs (1987, Molecular and Biochemical Parasitology 23, 285-296) megasomes were found to display acid phosphatase activity at both light and electron microscope levels. This, together with the demonstration that megasomes are acidified, suggests that these organelles may be targets for amino acid derivatives.
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Affiliation(s)
- J C Antoine
- Unité d'Immunophysiologie cellulaire de l'Institut Pasteur et du C.N.R.S. (UA 1113), Paris, France
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Marko M, Leith A, Parsons D. Three-dimensional reconstruction of cells from serial sections and whole-cell mounts using multilevel contouring of stereo micrographs. JOURNAL OF ELECTRON MICROSCOPY TECHNIQUE 1988; 9:395-411. [PMID: 2462031 DOI: 10.1002/jemt.1060090406] [Citation(s) in RCA: 58] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
A comprehensive computer-graphics-based system (STERECON) is described for tracing and digitizing contours from individual or stereopair electron micrographs. The contours are drawn in parallel planes within the micrographs. Provision is also made for tracing and digitizing in full three-dimensional (3-D) coordinates in any direction along linear structures such as cytoskeletal elements. The stereopair micrographs are viewed in combination with the contours being traced on a graphics terminal monitor. This is done either by projecting original electron micrograph (EM) negatives onto a screen and optically combining these images with contour lines being drawn on the monitor, or by first digitizing the images and displaying them directly on the monitor along with the contour lines. Prior image digitization allows computer enhancement of the structures to be contoured. Correction and alignment routines are included to deal with variable section thickness, section distortion and mass loss, variations in photography in the electron microscope, and terminal screen curvature when combining projected images with contour lines on the monitor. The STERECON system organizes and displays the digitized data from successive sections as a 3-D reconstruction. Reconstructions can be viewed in any orientation as contour stacks with hidden lines removed; as wire-frame models; or as shaded, solid models with variable lighting, transparency, and reflectivity. Volumes and surface areas of the reconstructed objects can be determined. Particular attention was paid to making the system convenient for the biological user. Users are given a choice of three different stereo-viewing methods.
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Affiliation(s)
- M Marko
- Wadsworth Center for Laboratories and Research, New York State Department of Health, Albany 12201
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Hassan HF, Coombs GH. Phosphomonoesterases of Leishmania mexicana mexicana and other flagellates. Mol Biochem Parasitol 1987; 23:285-96. [PMID: 3037369 DOI: 10.1016/0166-6851(87)90035-1] [Citation(s) in RCA: 50] [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
Amastigotes and log-phase promastigotes of Leishmania mexicana mexicana contained distinct acid phosphatase, 3'-nucleotidase and 5'-nucleotidase activities, distinguishable by their response to pH and inhibitors. Both tartrate-sensitive and tartrate-resistant acid phosphatase were present in the two forms, amastigotes possessed less tartrate-resistant acid phosphatase than promastigotes. A tartrate-sensitive acid phosphatase was secreted into the medium in large amounts during the growth in vitro of L. m. mexicana promastigotes. The 5'-nucleotidase activity of both parasite forms was inhibited by ammonium molybdate, sodium tartrate and, to less extent, by sodium fluoride whereas 3'-nucleotidase was inhibited by EDTA. All three activities were shown to be present on the external surface of both amastigotes and promastigotes. The three phosphomonoesterase activities were also detected in extracts of L. m. amazonensis, L. donovani, L. tarentolae, Crithidia fasciculata, Herpetomonas muscarum muscarum, H.m. ingenoplastis and Trichomitus batrachorum whereas 5'-nucleotidase was not detected in Trypanosoma brucei brucei extract and 3'-nucleotidase was absent from extracts of Trichomonas vaginalis and Tritrichomonas foetus.
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Abstract
Leishmania mexicana mexicana (M379) amastigotes were found to contain much higher activities than cultured promastigotes of five putative lysosomal enzymes: cysteine proteinase; arylsulfatase (EC 3.1.6.1); beta-glucuronidase (EC 3.2.1.31); DNase (EC 3.1.22.1), and RNase (EC 3.1.27.1). The release profiles of the first three of these enzymes from digitonin-permeabilized amastigotes suggests that they are located within organelles. Cytochemical staining for cysteine proteinase, using gold labeled antibodies and arylsulfatase, showed that both were present in large organelles previously named "megasomes." Comparative studies with L. mexicana amazonensis (LV78), L. donovani donovani (LV9), and L. major (LV39) revealed that L. mexicana amazonensis was similar to L. mexicana mexicana in possessing both high amastigote cysteine proteinase activity and large numbers of megasome organelles in amastigotes, whereas the other two species lacked both these features. The results suggest that the presence of numerous lysosome-like organelles in the amastigote is a characteristic of the L. mexicana group of parasites.
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