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Alhazmi A, Sidney LE, Hopkinson A, Elsheikha HM. Comparative cytotoxicity of Acanthamoeba castellanii-derived conditioned medium on human corneal epithelial and stromal cells. Acta Trop 2024; 257:107288. [PMID: 38901524 DOI: 10.1016/j.actatropica.2024.107288] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2024] [Revised: 06/10/2024] [Accepted: 06/11/2024] [Indexed: 06/22/2024]
Abstract
Soluble factors in the secretome of Acanthamoeba castellanii play crucial roles in the pathogenesis of Acanthamoeba keratitis (AK). Investigating the pathological effects of A. castellanii-derived conditioned medium (ACCM) on ocular cells can provide insights into the damage inflicted during AK. This study examined ACCM-induced cytotoxicity in primary human corneal stromal cells (CSCs) and a human SV40 immortalized corneal epithelial cell line (ihCECs) at varying ACCM concentrations (25 %, 50 %, 75 %, and 100 %). MTT, AlamarBlue, Sulforhodamine B, lactate dehydrogenase, and Caspase-3/7 activation assays were used to assess the impact of ACCM on the cell viability, proliferation and apoptosis. Additionally, fluorescent staining was used to reveal actin cytoskeleton changes. ACCM exposure significantly decreased cell viability, increased apoptosis, and disrupted the actin cytoskeleton, particularly at higher concentrations and longer exposures. Proteases were found to mediate these cytopathogenic effects, highlighting the need for characterization of A. castellanii proteases as key virulence factors in AK pathogenesis.
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Affiliation(s)
- Abdullah Alhazmi
- Academic Ophthalmology, Division of Clinical Neuroscience, University of Nottingham, Nottingham NG7 2UH, UK; Faculty of Public Health and Health Informatics, Umm Al Qura University, Makkah, Saudi Arabia
| | - Laura E Sidney
- Academic Ophthalmology, Division of Clinical Neuroscience, University of Nottingham, Nottingham NG7 2UH, UK
| | - Andy Hopkinson
- Academic Ophthalmology, Division of Clinical Neuroscience, University of Nottingham, Nottingham NG7 2UH, UK
| | - Hany M Elsheikha
- Faculty of Medicine and Health Sciences, School of Veterinary Medicine and Science, University of Nottingham, Sutton Bonington Campus, Loughborough LE12 5RD, UK.
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Loufouma-Mbouaka A, Martín-Pérez T, Köhsler M, Danisman Z, Schwarz M, Mazumdar R, Samba-Louaka A, Walochnik J. Characterization of novel extracellular proteases produced by Acanthamoeba castellanii after contact with human corneal epithelial cells and their relevance to pathogenesis. Parasit Vectors 2024; 17:242. [PMID: 38812022 PMCID: PMC11137893 DOI: 10.1186/s13071-024-06304-7] [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: 02/23/2024] [Accepted: 04/24/2024] [Indexed: 05/31/2024] Open
Abstract
BACKGROUND Proteases produced by Acanthamoeba spp. play an important role in their virulence and may be the key to understanding Acanthamoeba pathogenesis; thus, increasing attention has been directed towards these proteins. The present study aimed to investigate the lytic factors produced by Acanthamoeba castellanii during the first hours of in vitro co-culture with human corneal epithelial cells (HCECs). METHODS We used one old and one recent Acanthamoeba isolate, both from patients with severe keratitis, and subsets of these strains with enhanced pathogenic potential induced by sequential passaging over HCEC monolayers. The proteolytic profiles of all strains and substrains were examined using 1D in-gel zymography. RESULTS We observed the activity of additional proteases (ranging from 33 to 50 kDa) during the early interaction phase between amoebae and HCECs, which were only expressed for a short time. Based on their susceptibilities to protease inhibitors, these proteases were characterized as serine proteases. Protease activities showed a sharp decline after 4 h of co-incubation. Interestingly, the expression of Acanthamoeba mannose-binding protein did not differ between amoebae in monoculture and those in co-culture. Moreover, we observed the activation of matrix metalloproteinases in HCECs after contact with Acanthamoeba. CONCLUSIONS This study revealed the involvement of two novel serine proteases in Acanthamoeba pathogenesis and suggests a pivotal role of serine proteases during Acanthamoeba-host cell interaction, contributing to cell adhesion and lysis.
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Affiliation(s)
- Alvie Loufouma-Mbouaka
- Center for Pathophysiology, Infectiology and Immunology, Institute of Specific Prophylaxis and Tropical Medicine, Medical University of Vienna, Vienna, Austria
| | - Tania Martín-Pérez
- Center for Pathophysiology, Infectiology and Immunology, Institute of Specific Prophylaxis and Tropical Medicine, Medical University of Vienna, Vienna, Austria
| | - Martina Köhsler
- Center for Pathophysiology, Infectiology and Immunology, Institute of Specific Prophylaxis and Tropical Medicine, Medical University of Vienna, Vienna, Austria
| | - Zeynep Danisman
- Center for Pathophysiology, Infectiology and Immunology, Institute of Specific Prophylaxis and Tropical Medicine, Medical University of Vienna, Vienna, Austria
| | - Maya Schwarz
- Center for Pathophysiology, Infectiology and Immunology, Institute of Specific Prophylaxis and Tropical Medicine, Medical University of Vienna, Vienna, Austria
| | - Rounik Mazumdar
- Max Perutz Labs Vienna, Department of Medical Biochemistry, Medical University of Vienna, Vienna, Austria
- GenomeByte Ltd, London, UK
| | - Ascel Samba-Louaka
- Laboratoire Ecologie Et Biologie Des Interactions, Université de Poitiers, UMR CNRS, 7267, Poitiers, France
| | - Julia Walochnik
- Center for Pathophysiology, Infectiology and Immunology, Institute of Specific Prophylaxis and Tropical Medicine, Medical University of Vienna, Vienna, Austria.
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Ferreira MDS, Gonçalves DDS, Mendoza SR, de Oliveira GA, Pontes B, la Noval CRD, Honorato L, Ramos LFC, Nogueira FCS, Domont GB, Casadevall A, Nimrichter L, Peralta JM, Guimaraes AJ. β-1,3-Glucan recognition by Acanthamoeba castellanii as a putative mechanism of amoeba-fungal interactions. Appl Environ Microbiol 2024; 90:e0173623. [PMID: 38259076 PMCID: PMC10880599 DOI: 10.1128/aem.01736-23] [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: 10/03/2023] [Accepted: 12/15/2023] [Indexed: 01/24/2024] Open
Abstract
In this study, we conducted an in-depth analysis to characterize potential Acanthamoeba castellanii (Ac) proteins capable of recognizing fungal β-1,3-glucans. Ac specifically anchors curdlan or laminarin, indicating the presence of surface β-1,3-glucan-binding molecules. Using optical tweezers, strong adhesion of laminarin- or curdlan-coated beads to Ac was observed, highlighting their adhesive properties compared to controls (characteristic time τ of 46.9 and 43.9 s, respectively). Furthermore, Histoplasma capsulatum (Hc) G217B, possessing a β-1,3-glucan outer layer, showed significant adhesion to Ac compared to a Hc G186 strain with an α-1,3-glucan outer layer (τ of 5.3 s vs τ 83.6 s). The addition of soluble β-1,3-glucan substantially inhibited this adhesion, indicating the involvement of β-1,3-glucan recognition. Biotinylated β-1,3-glucan-binding proteins from Ac exhibited higher binding to Hc G217B, suggesting distinct recognition mechanisms for laminarin and curdlan, akin to macrophages. These observations hinted at the β-1,3-glucan recognition pathway's role in fungal entrance and survival within phagocytes, supported by decreased fungal viability upon laminarin or curdlan addition in both phagocytes. Proteomic analysis identified several Ac proteins capable of binding β-1,3-glucans, including those with lectin/glucanase superfamily domains, carbohydrate-binding domains, and glycosyl transferase and glycosyl hydrolase domains. Notably, some identified proteins were overexpressed upon curdlan/laminarin challenge and also demonstrated high affinity to β-1,3-glucans. These findings underscore the complexity of binding via β-1,3-glucan and suggest the existence of alternative fungal recognition pathways in Ac.IMPORTANCEAcanthamoeba castellanii (Ac) and macrophages both exhibit the remarkable ability to phagocytose various extracellular microorganisms in their respective environments. While substantial knowledge exists on this phenomenon for macrophages, the understanding of Ac's phagocytic mechanisms remains elusive. Recently, our group identified mannose-binding receptors on the surface of Ac that exhibit the capacity to bind/recognize fungi. However, the process was not entirely inhibited by soluble mannose, suggesting the possibility of other interactions. Herein, we describe the mechanism of β-1,3-glucan binding by A. castellanii and its role in fungal phagocytosis and survival within trophozoites, also using macrophages as a model for comparison, as they possess a well-established mechanism involving the Dectin-1 receptor for β-1,3-glucan recognition. These shed light on a potential parallel evolution of pathways involved in the recognition of fungal surface polysaccharides.
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Affiliation(s)
- Marina da Silva Ferreira
- Laboratório de Bioquímica e Imunologia das Micoses, Departamento de Microbiologia e Parasitologia, Instituto Biomédico, Universidade Federal Fluminense, Niterói, Rio de Janeiro, Brazil
- Programa de Pós-Graduação em Imunologia e Inflamação, Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Niterói, Rio de Janeiro, Brazil
| | - Diego de Souza Gonçalves
- Programa de Pós-Graduação em Doenças Infecciosas e Parasitárias, Faculdade de Medicina, Universidade Federal do Rio de Janeiro, Niterói, Rio de Janeiro, Brazil
| | - Susana Ruiz Mendoza
- Laboratório de Bioquímica e Imunologia das Micoses, Departamento de Microbiologia e Parasitologia, Instituto Biomédico, Universidade Federal Fluminense, Niterói, Rio de Janeiro, Brazil
- Programa de Pós-Graduação em Imunologia e Inflamação, Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Niterói, Rio de Janeiro, Brazil
| | - Gabriel Afonso de Oliveira
- Laboratório de Bioquímica e Imunologia das Micoses, Departamento de Microbiologia e Parasitologia, Instituto Biomédico, Universidade Federal Fluminense, Niterói, Rio de Janeiro, Brazil
| | - Bruno Pontes
- Instituto de Ciências Biomédicas e Centro Nacional de Biologia Estrutural e Bioimagem, Universidade Federal do Rio de Janeiro, Niterói, Rio de Janeiro, Brazil
| | - Claudia Rodríguez-de la Noval
- Laboratório de Bioquímica e Imunologia das Micoses, Departamento de Microbiologia e Parasitologia, Instituto Biomédico, Universidade Federal Fluminense, Niterói, Rio de Janeiro, Brazil
- Programa de Pós-Graduação em Doenças Infecciosas e Parasitárias, Faculdade de Medicina, Universidade Federal do Rio de Janeiro, Niterói, Rio de Janeiro, Brazil
| | - Leandro Honorato
- Laboratório de Glicobiologia de Eucariotos, Departamento de Microbiologia Geral, Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Niterói, Rio de Janeiro, Brazil
| | - Luis Felipe Costa Ramos
- Departamento de Bioquímica, Instituto de Química, Universidade Federal do Rio de Janeiro, Niterói, Rio de Janeiro, Brazil
| | - Fábio C. S. Nogueira
- Departamento de Bioquímica, Instituto de Química, Universidade Federal do Rio de Janeiro, Niterói, Rio de Janeiro, Brazil
| | - Gilberto B. Domont
- Departamento de Bioquímica, Instituto de Química, Universidade Federal do Rio de Janeiro, Niterói, Rio de Janeiro, Brazil
| | - Arturo Casadevall
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Leonardo Nimrichter
- Programa de Pós-Graduação em Imunologia e Inflamação, Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Niterói, Rio de Janeiro, Brazil
- Laboratório de Glicobiologia de Eucariotos, Departamento de Microbiologia Geral, Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Niterói, Rio de Janeiro, Brazil
- Rede Micologia RJ - Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ), Niterói, Rio de Janeiro, Brazil
| | - Jose Mauro Peralta
- Programa de Pós-Graduação em Doenças Infecciosas e Parasitárias, Faculdade de Medicina, Universidade Federal do Rio de Janeiro, Niterói, Rio de Janeiro, Brazil
| | - Allan J. Guimaraes
- Laboratório de Bioquímica e Imunologia das Micoses, Departamento de Microbiologia e Parasitologia, Instituto Biomédico, Universidade Federal Fluminense, Niterói, Rio de Janeiro, Brazil
- Programa de Pós-Graduação em Imunologia e Inflamação, Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Niterói, Rio de Janeiro, Brazil
- Rede Micologia RJ - Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ), Niterói, Rio de Janeiro, Brazil
- Pós-Graduação em Microbiologia e Parasitologia Aplicadas, Instituto Biomédico, Universidade Federal Fluminense, Niterói, Rio de Janeiro, Brazil
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Mahdavi Poor B, Rashedi J, Asgharzadeh V, Mirmazhary A, Gheitarani N. Proteases of Acanthamoeba. Parasitol Res 2023; 123:19. [PMID: 38063887 DOI: 10.1007/s00436-023-08059-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Accepted: 10/27/2023] [Indexed: 12/18/2023]
Abstract
The members of genus Acanthamoeba are the etiological agent of uncommon but severe or even fatal opportunistic infections in human beings. The presence of different classes of intracellular and extracellular proteases including serine proteases, cysteine proteases, and metalloproteases has been well documented in environmental and clinical isolates of Acanthamoeba spp. However, the role of the proteolytic enzymes in physiological, biological, and pathological mechanisms of the amoeba remains partially investigated. Some attempts have been conducted using various methods to determine the profile of proteases (number, class, optimal conditions, and activity of the enzymes), and possible pathogenicity mechanism of the proteolytic enzymes (various protein substrate degradation, cytopathic effect on different cell lines). In some cases, it was attempted to correlate intracellular and extracellular protease profile with pathogenicity potential of strains. This review revealed that the protease profile of different strains of Acanthamoeba was extremely complex, therefore, further comprehensive studies with application of a combination of various methods may help to elucidate the role of the enzymes.
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Affiliation(s)
- Behroz Mahdavi Poor
- Department of Laboratory Sciences, Faculty of Paramedicine, Tabriz University of Medical Sciences, Golgasht Ave, Azadi St, Tabriz, Iran.
| | - Jalil Rashedi
- Department of Laboratory Sciences, Faculty of Paramedicine, Tabriz University of Medical Sciences, Golgasht Ave, Azadi St, Tabriz, Iran
| | - Vahid Asgharzadeh
- Student Research Committee, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Amirali Mirmazhary
- Department of Laboratory Sciences, Faculty of Paramedicine, Tabriz University of Medical Sciences, Golgasht Ave, Azadi St, Tabriz, Iran
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Son DH, Kim EJ, Matin A, Jung SY. Interaction between Naegleria fowleri and pathogenic Escherichia coli by mannose and changes in N. fowleri protease. Parasitol Res 2022; 121:1805-1809. [DOI: 10.1007/s00436-022-07513-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Accepted: 04/04/2022] [Indexed: 10/18/2022]
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Kim DY, Son DH, Matin A, Jung SY. Production of a monoclonal antibody against a galactose-binding protein of Acanthamoeba castellanii and its cytotoxicity. Parasitol Res 2021; 120:3845-3850. [PMID: 34561750 DOI: 10.1007/s00436-021-07321-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Accepted: 09/15/2021] [Indexed: 11/29/2022]
Abstract
In this study, it was confirmed whether the galactose-binding protein (GBP) was present in Acanthamoeba castellanii, and its function on a target cell was confirmed by production of an antibody against the GBP. Since the genes for GBP have not yet been identified at all, the purification of GBP was done using galactose-beads from amoebial lysates, and monoclonal antibodies were produced using cell fusion. GBP was confirmed to have a size of about 35 kDa. After the third immunization with purified GBP in BALB/c mice, monoclonal antibody production was analyzed. The clone cultured before limiting dilution was named 2AB2 and showed the highest antibody titer in the culture supernatant of a 24-well plate. AF6 clone cultured after limiting dilution showed an antibody titer of 0.259 in a 75-T flask. Antibodies generated by collecting ascites by injecting monoclonal colonies into the abdominal cavity of mice were confirmed through gel analysis and were observed to belong to the isotype of the IgM having kappa chains. Since the cytotoxicity of A. castellanii was inhibited by about 26% by the monoclonal antibody against GBP, it was confirmed that the antibody against GBP had an inhibitory effect on cytotoxicity. This study was the first report on GBP isolated and purified from A. castellanii, and similarly to a mannose-binding protein (MBP), its involvement in contact-dependent cytotoxicity was demonstrated with monoclonal antibody production.
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Affiliation(s)
- Dong-Youn Kim
- Department of Biomedical Laboratory Science, Molecular Diagnostics Research Institute, Namseoul University, 91 Daehak-ro, Seonghwan-eup, Cheonan, 31020, Republic of Korea
| | - Dae-Hyun Son
- Department of Biomedical Laboratory Science, Molecular Diagnostics Research Institute, Namseoul University, 91 Daehak-ro, Seonghwan-eup, Cheonan, 31020, Republic of Korea
| | - Abdul Matin
- Department of Biological Science, University of Baltistan, Kargil Road, Main Campus, SkarduHussainabad, Gilgit-Baltistan, 16100, Pakistan
| | - Suk-Yul Jung
- Department of Biomedical Laboratory Science, Molecular Diagnostics Research Institute, Namseoul University, 91 Daehak-ro, Seonghwan-eup, Cheonan, 31020, Republic of Korea.
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7
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Chauhan D, Shames SR. Pathogenicity and Virulence of Legionella: Intracellular replication and host response. Virulence 2021; 12:1122-1144. [PMID: 33843434 PMCID: PMC8043192 DOI: 10.1080/21505594.2021.1903199] [Citation(s) in RCA: 45] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Bacteria of the genus Legionella are natural pathogens of amoebae that can cause a severe pneumonia in humans called Legionnaires’ Disease. Human disease results from inhalation of Legionella-contaminated aerosols and subsequent bacterial replication within alveolar macrophages. Legionella pathogenicity in humans has resulted from extensive co-evolution with diverse genera of amoebae. To replicate intracellularly, Legionella generates a replication-permissive compartment called the Legionella-containing vacuole (LCV) through the concerted action of hundreds of Dot/Icm-translocated effector proteins. In this review, we present a collective overview of Legionella pathogenicity including infection mechanisms, secretion systems, and translocated effector function. We also discuss innate and adaptive immune responses to L. pneumophila, the implications of Legionella genome diversity and future avenues for the field.
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Affiliation(s)
- Deepika Chauhan
- Division of Biology, Kansas State University, Manhattan, Kansas, USA
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8
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Lima PC, Hartley-Tassell L, Cooper O, Wynne JW. Searching for the sweet spot of amoebic gill disease of farmed Atlantic salmon: the potential role of glycan-lectin interactions in the adhesion of Neoparamoeba perurans. Int J Parasitol 2021; 51:545-557. [PMID: 33675796 DOI: 10.1016/j.ijpara.2020.11.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 11/04/2020] [Accepted: 11/15/2020] [Indexed: 01/25/2023]
Abstract
One of the first critical steps in the pathogenesis of amoebic gill disease (AGD) of farmed salmon is the adhesion of the causative amoeba to the host. The current study aimed to investigate the potential involvement of glycan-binding proteins expressed on the extracellular surface of Neoparamoeba perurans in gill tissue recognition and binding. The glycan-binding properties of the surface membrane of N. perurans and the carbohydrate binding profile of Atlantic salmon gill-derived epithelial cells were identified through the use of glycan and lectin microarrays, respectively. The occurrence of specific carbohydrate-mediated binding was then further assessed by in vitro attachment assays using microtitre plates pre-coated with the main glycan candidates. Adhesion assays were also performed in the presence of exogenous saccharides with the aim of blocking glycan-specific binding activity. Comparative analysis of the results from both lectin and glycan arrays showed significant overlap, as some glycans to which binding by the amoeba was seen were reflected as being present on the gill epithelial cells. The two main candidates proposed to be involved in amoeba attachment to the gills are mannobiose and N-acetylgalactosamine (GalNAc). Adhesion of amoebae significantly increased by 33.5 and 23% when cells were added to α1,3-Mannobiose-BSA and GalNAc-BSA coated plates. The observed increased in attachment was significantly reduced when the amoebae were incubated with exogenous glycans, further demonstrating the presence of mannobiose- and GalNAc-binding sites on the surfaces of the cells. We believe this study provides the first evidence for the presence of a highly specific carbohydrate recognition and binding system in N. perurans. These preliminary findings could be of extreme importance given that AGD is an external parasitic infestation and much of the current research on the development of alternative treatment strategies relies on either instant amoeba detachment or blocking parasite attachment.
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Affiliation(s)
- P C Lima
- CSIRO Agriculture and Food, Livestock & Aquaculture, Queensland Biosciences Precinct, 306 Carmody Road, Brisbane, QLD 4067, Australia.
| | - L Hartley-Tassell
- Institute for Glycomics, Griffith University, Gold Coast Campus, Gold Coast, QLD 4222, Australia
| | - O Cooper
- Institute for Glycomics, Griffith University, Gold Coast Campus, Gold Coast, QLD 4222, Australia
| | - J W Wynne
- CSIRO Agriculture and Food, Livestock & Aquaculture, Castray Esplanade, Battery Point, TAS 7004, Australia
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Carvalho-Silva AC, Coelho CH, Cirelli C, Crepaldi F, Rodrigues-Chagas IA, Furst C, Pimenta DC, Toledo JSD, Fernandes AP, Costa AO. Differential expression of Acanthamoeba castellanii proteins during amoebic keratitis in rats. Exp Parasitol 2020; 221:108060. [PMID: 33338467 DOI: 10.1016/j.exppara.2020.108060] [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: 04/01/2020] [Revised: 11/04/2020] [Accepted: 12/13/2020] [Indexed: 11/25/2022]
Abstract
Amoebic keratitis (AK) is a sight-threatening infection characterized by a severe inflammation of the cornea, caused by the free-living protozoan of the genus Acanthamoeba. Identification of amoebic proteins involved in AK pathogenesis may help to elucidate molecular mechanisms of infection and contribute to indicate diagnostic and therapeutic targets. In this study, we evaluated changes in the expression profile of Acanthamoeba proteins triggered by the invasive process, using an approach involving two-dimensional polyacrylamide gel electrophoresis (2DE PAGE), followed by mass spectrometry identification (ESI-IT-TOF LC-MSn). AK was induced by intrastromal inoculation in Wistar rats, using trophozoites from a T4 genotype, human case-derived A. castellanii strain under prolonged axenic culture. Cultures re-isolated from the lesions after two successive passages in the animals were used as biological triplicate for proteomic experiments. Analysis of the protein profile comparing long-term and re-isolated cultures indicated 62 significant spots, from which 27 proteins could be identified in the Acanthamoeba proteome database. Five of them (Serpin, Carboxypeptidase A1, Hypothetical protein, Calponin domain-containing protein, aldo/keto reductase) were exclusively found in the re-isolated trophozoites. Our analysis also revealed that a concerted modulation of several biochemical pathways is triggered when A. castellanii switches from a free-living style to a parasitic mode, including energetic metabolism, proteolytic activity, control of gene expression, protein degradation and methylation of DNA, which may be also involved in gain of virulence in an animal model of AK.
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Affiliation(s)
- Ana Carolina Carvalho-Silva
- Department of Clinical and Toxicological Analysis, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
| | - Camila H Coelho
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Cecília Cirelli
- Department of Clinical and Toxicological Analysis, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
| | - Frederico Crepaldi
- Department of Clinical and Toxicological Analysis, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
| | | | - Cinthia Furst
- Department of Pathology, Health Sciences Center, Federal University of Espírito Santo, Vitória, ES, Brazil
| | | | - Juliano Simões de Toledo
- Department of Clinical and Toxicological Analysis, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
| | - Ana Paula Fernandes
- Department of Clinical and Toxicological Analysis, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
| | - Adriana Oliveira Costa
- Department of Clinical and Toxicological Analysis, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil.
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Angelici MC, Walochnik J, Calderaro A, Saxinger L, Dacks JB. Free-living amoebae and other neglected protistan pathogens: Health emergency signals? Eur J Protistol 2020; 77:125760. [PMID: 33340850 DOI: 10.1016/j.ejop.2020.125760] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 10/25/2020] [Accepted: 11/13/2020] [Indexed: 02/08/2023]
Abstract
Protistan parasites have an undisputed global health impact. However, outside of a few key exceptions, e.g. the agent of malaria, most of these infectious agents are neglected as important health threats. The Symposium entitled "Free-living amoebae and neglected pathogenic protozoa: health emergency signals?" held at the European Congress of Protistology in Rome, July 2019, brought together researchers addressing scientific and clinical questions about some of these fascinating organisms. Topics presented included the molecular basis of pathogenicity in Acanthamoeba; genomics of Naegleria fowleri; and epidemiology of poorly diagnosed enteric protistan species, including Giardia, Cryptosporidium, Blastocystis, Dientamoeba. The Symposium aim was to excite the audience about the opportunities and challenges of research in these underexplored organisms and to underline the public health implications of currently under-appreciated protistan infections. The major take home message is that any knowledge that we gain about these organisms will allow us to better address them, in terms of monitoring and treatment, as sources of future health emergencies.
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Affiliation(s)
| | - Julia Walochnik
- Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria
| | - Adriana Calderaro
- Department of Medicine and Surgery, University of Parma, Parma, Italy
| | - Lynora Saxinger
- Division of Infectious Diseases, Department of Medicine, University of Alberta, Alberta, Canada
| | - Joel B Dacks
- Division of Infectious Diseases, Department of Medicine, University of Alberta, Alberta, Canada; Institute of Parasitology, Biology Centre, Czech Academy of Sciences České Budějovice, Czech Republic.
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11
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Morphological Description of the Early Events during the Invasion of Acanthamoeba castellanii Trophozoites in a Murine Model of Skin Irradiated under UV-B Light. Pathogens 2020; 9:pathogens9100794. [PMID: 32992452 PMCID: PMC7600863 DOI: 10.3390/pathogens9100794] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Revised: 08/27/2020] [Accepted: 09/24/2020] [Indexed: 11/17/2022] Open
Abstract
Skin infections have been associated with Acanthamoeba, nevertheless the events during skin invasion and UV-B light effects on it are unknown. The early morphological events of Acanthamoeba castellanii skin invasion are shown in SKH-1 mice that were chronically UV-B light irradiated. Mice that developed skin lesions (group 1) were topical and intradermally inoculated with A. castellanii trophozoites and sacrificed 48 h or 18 days later. Mice that showed no skin lesions (group 2) were intradermally inoculated and sacrificed 24, 48 or 72 h later. Mice ventral areas were considered controls with and without trophozoites intradermally inoculated. Skin samples were processed by histological and immunohistochemistry techniques. In group 1, trophozoites were immunolocalized in dermal areas, hair cysts, sebaceous glands, and blood vessels, and collagen degradation was observed. One of these mice shown trophozoites in the spleen, liver, and brain. In group 2, few trophozoites nearby collagenolytic activity zones were observed. In control samples, nor histological damage and no trophozoites were observed. Adherence and collagenolytic activity by A. castellanii were corroborated in vitro. We can infer that UV-B light irradiated skin could favor A. castellanii invasiveness causing damage in sites as far away as the brain, confirming the invasive capacity and pathogenic potential of these amphizoic amoebae.
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Guzmán-Téllez P, Martínez-Castillo M, Flores-Huerta N, Rosales-Morgan G, Pacheco-Yépez J, la Garza MD, Serrano-Luna J, Shibayama M. Lectins as virulence factors in Entamoeba histolytica and free-living amoebae. Future Microbiol 2020; 15:919-936. [PMID: 32716210 DOI: 10.2217/fmb-2019-0275] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Currently, there is growing interest in the identification and purification of microbial lectins due to their involvement in the pathogenicity mechanisms of pathogens, such as Entamoeba histolytica and free-living amoebae. The Gal/GalNAc lectin from E. histolytica participates in adhesion, cytotoxicity and regulation of immune responses. Furthermore, mannose- and galactose-binding protein have been described in Acanthamoeba castellanii and Balamuthia mandrillaris, respectively and they also contribute to host damage. Finally, in Naegleria fowleri, molecules containing mannose and fucose are implicated in adhesion and cytotoxicity. Considering their relevance in the pathogenesis of the diseases caused by these protozoa, lectins appear to be promising targets in the diagnosis, vaccination and treatment of these infections.
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Affiliation(s)
- Paula Guzmán-Téllez
- Department of Infectomics & Molecular Pathogenesis, Center for Research & Advanced Studies of The National Polytechnic Institute, Av. IPN 2508, Mexico City 07360, Mexico
| | - Moisés Martínez-Castillo
- Department of Infectomics & Molecular Pathogenesis, Center for Research & Advanced Studies of The National Polytechnic Institute, Av. IPN 2508, Mexico City 07360, Mexico
- Department of Experimental Medicine, Liver, Pancreas & Motility Laboratory (HIPAM), School of Medicine, National Autonomous University of Mexico (UNAM) Mexico City, Mexico
| | - Nadia Flores-Huerta
- Department of Infectomics & Molecular Pathogenesis, Center for Research & Advanced Studies of The National Polytechnic Institute, Av. IPN 2508, Mexico City 07360, Mexico
| | - Gabriela Rosales-Morgan
- Department of Infectomics & Molecular Pathogenesis, Center for Research & Advanced Studies of The National Polytechnic Institute, Av. IPN 2508, Mexico City 07360, Mexico
| | - Judith Pacheco-Yépez
- Sección de Estudios de Posgrado e Investigación, Escuela Superior de Medicina, Instituto Politécnico Nacional, Ciudad de México, México
| | - Mireya de la Garza
- Department of Cell Biology, Center for Research & Advanced Studies of The National Polytechnic Institute, Av. IPN 2508, Mexico City 07360, Mexico
| | - Jesús Serrano-Luna
- Department of Cell Biology, Center for Research & Advanced Studies of The National Polytechnic Institute, Av. IPN 2508, Mexico City 07360, Mexico
| | - Mineko Shibayama
- Department of Infectomics & Molecular Pathogenesis, Center for Research & Advanced Studies of The National Polytechnic Institute, Av. IPN 2508, Mexico City 07360, Mexico
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Abstract
Since the discovery of mimivirus, numerous giant viruses associated with free-living amoebae have been described. The genome of giant viruses can be more than 2.5 megabases, and virus particles can exceed the size of many bacteria. The unexpected characteristics of these viruses have made them intriguing research targets and, as a result, studies focusing on their interactions with their amoeba host have gained increased attention. Studies have shown that giant viruses can establish host-pathogen interactions, which have not been previously demonstrated, including the unprecedented interaction with a new group of small viruses, called virophages, that parasitize their viral factories. In this brief review, we present recent advances in virophage-giant virus-host interactions and highlight selected studies involving interactions between giant viruses and amoebae. These unprecedented interactions involve the giant viruses mimivirus, marseillevirus, tupanviruses and faustovirus, all of which modulate the amoeba environment, affecting both their replication and their spread to new hosts.
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Khan NA, Anwar A, Siddiqui R. Acanthamoeba Keratitis: Current Status and Urgent Research Priorities. Curr Med Chem 2019; 26:5711-5726. [DOI: 10.2174/0929867325666180510125633] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Revised: 01/10/2018] [Accepted: 05/01/2018] [Indexed: 12/13/2022]
Abstract
Background:First discovered in the early 1970s, Acanthamoeba keratitis has remained a major eye infection and presents a significant threat to the public health, especially in developing countries. The aim is to present a timely review of our current understanding of the advances made in this field in a comprehensible manner and includes novel concepts and provides clear directions for immediate research priorities.Methods:We undertook a search of bibliographic databases for peer-reviewed research literature and also summarized our published results in this field.Results:The present review focuses on novel diagnostic and therapeutic strategies in details which can provide access to management and treatment of Acanthamoeba keratitis. This coupled with the recently available genome sequence information together with high throughput genomics technology and innovative approaches should stimulate interest in the rational design of preventative and therapeutic measures. Current treatment of Acanthamoeba keratitis is problematic and often leads to infection recurrence. Better understanding of diagnosis, pathogenesis, pathophysiology and therapeutic regimens, would lead to novel strategies in treatment and prophylaxis.
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Affiliation(s)
- Naveed Ahmed Khan
- Department of Biology, Chemistry and Environmental Sciences, College of Arts and Sciences, American University of Sharjah, University City, Sharjah, United Arab Emirates
| | - Ayaz Anwar
- Department of Biology, Chemistry and Environmental Sciences, College of Arts and Sciences, American University of Sharjah, University City, Sharjah, United Arab Emirates
| | - Ruqaiyyah Siddiqui
- Department of Biology, Chemistry and Environmental Sciences, College of Arts and Sciences, American University of Sharjah, University City, Sharjah, United Arab Emirates
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Acanthamoeba mauritaniensis genotype T4D: An environmental isolate displays pathogenic behavior. Parasitol Int 2019; 74:102002. [PMID: 31669294 DOI: 10.1016/j.parint.2019.102002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Revised: 10/08/2019] [Accepted: 10/21/2019] [Indexed: 12/13/2022]
Abstract
Acanthamoeba spp. are free-living amoebae with a worldwide distribution. These amoebae can cause granulomatous amoebic encephalitis and amoebic keratitis in humans. Proteases are considered virulence factors in pathogenic Acanthamoeba. The objective of this study was to evaluate the behavior of Acanthamoeba mauritaniensis, a nonpathogenic amoeba. We analyzed the cytopathic effect of A. mauritaniensis on RCE1(5 T5) and MDCK cells and compared it to that of Acanthamoeba castellanii. A partial biochemical characterization of proteases was performed in total crude extracts (TCE) and conditioned medium (CM). Finally, we evaluated the effect of proteases on tight junction (TJ) proteins and the transepithelial electrical resistance of MDCK cells. The results showed that this amoeba can induce substantial damage to RCE1(5T5) and MDCK cells. Moreover, the zymograms and Azocoll assays of amoebic TCE and CM revealed different protease activities, with serine proteases being the most active. Furthermore, A. mauritaniensis induced the alteration and degradation of MDCK cell TJ proteins with serine proteases. After genotyping this amoeba, we determined that it is an isolate of Acanthamoeba genotype T4D. From these data, we suggest that A. mauritaniensis genotype T4D behaves similarly to the A. castellanii strain.
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Tupanvirus-infected amoebas are induced to aggregate with uninfected cells promoting viral dissemination. Sci Rep 2019; 9:183. [PMID: 30655573 PMCID: PMC6336878 DOI: 10.1038/s41598-018-36552-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Accepted: 11/23/2018] [Indexed: 01/30/2023] Open
Abstract
The discovery of giant viruses in the last years has fascinated the scientific community due to virus particles size and genome complexity. Among such fantastic discoveries, we have recently described tupanviruses, which particles present a long tail, and has a genome that contains the most complete set of translation-related genes ever reported in the known virosphere. Here we describe a new kind of virus-host interaction involving tupanvirus. We observed that tupanvirus-infected amoebas were induced to aggregate with uninfected cells, promoting viral dissemination and forming giant host cell bunches. Even after mechanical breakdown of bunches, amoebas reaggregated within a few minutes. This remarkable interaction between infected and uninfected cells seems to be promoted by the expression of a mannose receptor gene. Our investigations demonstrate that the pre-treatment of amoebas with free mannose inhibits the formation of bunches, in a concentration-dependent manner, suggesting that amoebal-bunch formation correlates with mannose receptor gene expression. Finally, our data suggest that bunch-forming cells are able to interact with uninfected cells promoting the dissemination and increase of tupanvirus progeny.
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Kang AY, Park AY, Shin HJ, Khan NA, Maciver SK, Jung SY. Production of a monoclonal antibody against a mannose-binding protein of Acanthamoeba culbertsoni and its localization. Exp Parasitol 2018; 192:19-24. [PMID: 30031120 DOI: 10.1016/j.exppara.2018.07.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Revised: 06/21/2018] [Accepted: 07/17/2018] [Indexed: 10/28/2022]
Abstract
Amoebae from the genus Acanthamoeba are facultative pathogens of humans and other animals. In humans they most frequently infect the eye causing a sight threatening infection known as Acanthamoeba keratitis (AK), and also cause an often fatal encephalitis (GAE). A mannose-binding protein (MBP) has been identified as being important for Acanthamoeba infection especially in AK. This lectin has previously been characterized from Acanthamoeba castellanii as consisting of multiple 130 kDa subunits. MBP expression correlates with pathogenic potential and is expressed in a number of Acanthamoeba species. Here we report the purification of a similar lectin from Acanthamoeba culbertsoni and the production of a monoclonal antibody to it. The A. culbertsoni MBP was isolated by affinity chromatography using α-D-mannose agarose and has an apparent molecular weight of 83 kDa. The monoclonal antibody is an IgM that is useful in both western blots and immunofluorescence. We expect that this antibody will be useful in the study of the pathology of A. culbertsoni and in its identification in clinical samples.
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Affiliation(s)
- A-Young Kang
- Department of Biomedical Laboratory Science, Molecular Diagnostics Research Institute, Namseoul University, Cheonan 31020, Republic of Korea
| | - A-Young Park
- Department of Biomedical Laboratory Science, Molecular Diagnostics Research Institute, Namseoul University, Cheonan 31020, Republic of Korea
| | - Ho-Joon Shin
- Department of Microbiology, and Molecular Science & Technology, Ajou University School of Medicine, Suwon, 443-721, Republic of Korea
| | - Naveed Ahmed Khan
- Department of Biological Sciences, School of Science and Technology, Sunway University, Malaysia
| | - Sutherland K Maciver
- Centre for Discovery Brain Sciences, Biomedical Sciences, Edinburgh Medical School, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, Scotland, UK.
| | - Suk-Yul Jung
- Department of Biomedical Laboratory Science, Molecular Diagnostics Research Institute, Namseoul University, Cheonan 31020, Republic of Korea.
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Knowledge to Predict Pathogens: Legionella pneumophila Lifecycle Critical Review Part I Uptake into Host Cells. WATER 2018. [DOI: 10.3390/w10020132] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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Castro-Artavia E, Retana-Moreira L, Lorenzo-Morales J, Abrahams-Sandí E. Potentially pathogenic Acanthamoeba genotype T4 isolated from dental units and emergency combination showers. Mem Inst Oswaldo Cruz 2017; 112:817-821. [PMID: 29211242 PMCID: PMC5719550 DOI: 10.1590/0074-02760170147] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Accepted: 06/20/2017] [Indexed: 11/24/2022] Open
Abstract
BACKGROUND Acanthamoeba is the genus of free-living amoebae that is most frequently isolated in nature. To date, 20 Acanthamoeba genotypes have been described. Genotype T4 is responsible for approximately 90% of encephalitis and keratitis cases. Due to the ubiquitous presence of amoebae, isolation from environmental sources is not uncommon; to determine the clinical importance of an isolation, it is necessary to have evidence of the pathogenic potential of amoebae. OBJECTIVE The aim of this study was to physiologically characterise 8 Acanthamoeba T4 isolates obtained from dental units and emergency combination showers and to determine their pathogenic potential by employing different laboratory techniques. METHODS Eight axenic cultures of Acanthamoeba genotype T4 were used in pathogenic potential assays. Osmotolerance, thermotolerance, determination and characterisation of extracellular proteases and evaluation of cytopathic effects in MDCK cells were performed. FINDINGS All of the isolates were osmotolerant, thermotolerant and had serine proteases from 44-122 kDa. Two isolates had cytopathic effects on the MDCK cell monolayer. MAIN CONCLUSION The presence of Acanthamoeba T4 with pathogenic potential in areas such as those tested in this study reaffirms the need for adequate cleaning and maintenance protocols to reduce the possibility of infection with free-living amoebae.
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Affiliation(s)
- Esteban Castro-Artavia
- University of Costa Rica, Faculty of Microbiology, Department of Parasitology, San Pedro, San José, Costa Rica.,University of Costa Rica, Centro de Investigación en Enfermedades Tropicales, San Pedro, San José, Costa Rica
| | - Lissette Retana-Moreira
- University of Costa Rica, Faculty of Microbiology, Department of Parasitology, San Pedro, San José, Costa Rica.,University of Costa Rica, Centro de Investigación en Enfermedades Tropicales, San Pedro, San José, Costa Rica
| | - Jacob Lorenzo-Morales
- University of La Laguna, Institute of Tropical Diseases and Public Health of the Canary Islands, Tenerife, Spain
| | - Elizabeth Abrahams-Sandí
- University of Costa Rica, Faculty of Microbiology, Department of Parasitology, San Pedro, San José, Costa Rica.,University of Costa Rica, Centro de Investigación en Enfermedades Tropicales, San Pedro, San José, Costa Rica
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Characterization of extracellular proteases of Acanthamoeba genotype T4 isolated from different sources in Iran. Parasitol Res 2017; 116:3373-3380. [DOI: 10.1007/s00436-017-5656-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Accepted: 10/16/2017] [Indexed: 10/18/2022]
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21
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Huth S, Reverey JF, Leippe M, Selhuber-Unkel C. Adhesion forces and mechanics in mannose-mediated acanthamoeba interactions. PLoS One 2017; 12:e0176207. [PMID: 28472161 PMCID: PMC5417443 DOI: 10.1371/journal.pone.0176207] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2017] [Accepted: 04/06/2017] [Indexed: 12/15/2022] Open
Abstract
The human pathogenic amoeba Acanthamoeba castellanii (A. castellanii) causes severe diseases, including acanthamoeba keratitis and encephalitis. Pathogenicity arises from the killing of target-cells by an extracellular killing mechanism, where the crucial first step is the formation of a close contact between A. castellanii and the target-cell. This process is mediated by the glycocalix of the target-cell and mannose has been identified as key mediator. The aim of the present study was to carry out a detailed biophysical investigation of mannose-mediated adhesion of A. castellanii using force spectroscopy on single trophozoites. In detail, we studied the interaction of a mannose-coated cantilever with an A. castellanii trophozoite, as mannose is the decisive part of the cellular glycocalix in mediating pathogenicity. We observed a clear increase of the force to initiate cantilever detachment from the trophozoite with increasing contact time. This increase is also associated with an increase in the work of detachment. Furthermore, we also analyzed single rupture events during the detachment process and found that single rupture processes are associated with membrane tether formation, suggesting that the cytoskeleton is not involved in mannose binding events during the first few seconds of contact. Our study provides an experimental and conceptual basis for measuring interactions between pathogens and target-cells at different levels of complexity and as a function of interaction time, thus leading to new insights into the biophysical mechanisms of parasite pathogenicity.
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Affiliation(s)
- Steven Huth
- Institute of Materials Science, Biocompatible Nanomaterials, Christian-Albrechts-Universität zu Kiel, Kaiserstr. 2, D-24143 Kiel, Germany
| | - Julia F. Reverey
- Institute of Materials Science, Biocompatible Nanomaterials, Christian-Albrechts-Universität zu Kiel, Kaiserstr. 2, D-24143 Kiel, Germany
| | - Matthias Leippe
- Zoological Institute, Comparative Immunobiology, Christian-Albrechts-Universität zu Kiel, Am Botanischen Garten 1-9, 24118 Kiel, Germany
| | - Christine Selhuber-Unkel
- Institute of Materials Science, Biocompatible Nanomaterials, Christian-Albrechts-Universität zu Kiel, Kaiserstr. 2, D-24143 Kiel, Germany
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Lakhundi S, Siddiqui R, Khan NA. Pathogenesis of microbial keratitis. Microb Pathog 2017; 104:97-109. [DOI: 10.1016/j.micpath.2016.12.013] [Citation(s) in RCA: 86] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Revised: 11/30/2016] [Accepted: 12/05/2016] [Indexed: 01/03/2023]
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Singh RS, Walia AK, Kanwar JR. Protozoa lectins and their role in host–pathogen interactions. Biotechnol Adv 2016; 34:1018-1029. [DOI: 10.1016/j.biotechadv.2016.06.002] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Revised: 06/02/2016] [Accepted: 06/02/2016] [Indexed: 11/29/2022]
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Chávez-Munguía B, Salazar-Villatoro L, Omaña-Molina M, Espinosa-Cantellano M, Ramírez-Flores E, Lorenzo-Morales J, Martínez-Palomo A. Acanthamoeba culbertsoni: Electron-Dense Granules in a Highly Virulent Clinical Isolate. J Eukaryot Microbiol 2016; 63:744-750. [PMID: 27087641 DOI: 10.1111/jeu.12321] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Revised: 03/17/2016] [Accepted: 04/04/2016] [Indexed: 11/30/2022]
Abstract
The virulence of various amoebic parasites has been correlated with the presence of electron-dense granules (EDGs) in the cytoplasm of trophozoites. Here, we report the finding by transmission electron microscopy of a large number of EDGs in a recent culture of Acanthamoeba culbertsoni, isolated from a severe case of human keratitis. When this isolate was maintained in culture for 6 mo, the granules almost disappeared. However, after induction of mice brain lesions with the long-term cultured isolate, recovered amoebas had abundant EDGs. Trophozoites of the original isolate, or those recovered from experimental lesions, secreted EDGs into the medium when incubated with MDCK cells. To analyze a possible cytotoxic effect the conditioned medium was incubated with MDCK monolayers. After 5 h, the media containing EDGs produced opening of the tight junctions; at 24 h, cell viability was compromised, and at 48 h most of the cells were detached from the monolayer. In contrast, trophozoites in long-term cultures did not release EDGs to the medium during incubation with MDCK cells, and the corresponding conditioned medium did not have any effect on MDCK monolayers. Our observations further support the hypothesis that EDGs play a role in the cytopathogenic mechanisms of A. culbertsoni.
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Affiliation(s)
- Bibiana Chávez-Munguía
- Department of Infectomics and Molecular Pathogenesis, Center for Research and Advanced Studies, Mexico City, 07360, Mexico.
| | - Lizbeth Salazar-Villatoro
- Department of Infectomics and Molecular Pathogenesis, Center for Research and Advanced Studies, Mexico City, 07360, Mexico
| | - Maritza Omaña-Molina
- School of Superior Studies Iztacala, National Autonomous University of Mexico, Mexico City, 54090, Mexico
| | - Martha Espinosa-Cantellano
- Department of Infectomics and Molecular Pathogenesis, Center for Research and Advanced Studies, Mexico City, 07360, Mexico
| | - Elizabeth Ramírez-Flores
- School of Superior Studies Iztacala, National Autonomous University of Mexico, Mexico City, 54090, Mexico
| | - Jacob Lorenzo-Morales
- University Institute of Tropical Diseases and Public Health of the Canary Islands, University of La Laguna, Canary Islands, 38203, Spain
| | - Adolfo Martínez-Palomo
- Department of Infectomics and Molecular Pathogenesis, Center for Research and Advanced Studies, Mexico City, 07360, Mexico
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Arnold JW, Spacht D, Koudelka GB. Determinants that govern the recognition and uptake of
Escherichia coli
O157 : H7 by
Acanthamoeba castellanii. Cell Microbiol 2016; 18:1459-70. [DOI: 10.1111/cmi.12591] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2015] [Revised: 03/07/2016] [Accepted: 03/08/2016] [Indexed: 11/28/2022]
Affiliation(s)
- Jason W. Arnold
- Department of Biological Sciences University at Buffalo Buffalo NY 14260 USA
| | - Drew Spacht
- Department of Biology Mercyhurst University Erie PA 16546 USA
- Department of Entomology The Ohio State University 318 W. 12th Ave. 300 Aronoff Laboratory Columbus OH 43210 USA
| | - Gerald B. Koudelka
- Department of Biological Sciences University at Buffalo Buffalo NY 14260 USA
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Lee YR, Na BK, Moon EK, Song SM, Joo SY, Kong HH, Goo YK, Chung DI, Hong Y. Essential Role for an M17 Leucine Aminopeptidase in Encystation of Acanthamoeba castellanii. PLoS One 2015; 10:e0129884. [PMID: 26075721 PMCID: PMC4468156 DOI: 10.1371/journal.pone.0129884] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Accepted: 05/14/2015] [Indexed: 11/19/2022] Open
Abstract
Encystation of Acanthamoeba leads to the formation of resilient cysts from vegetative trophozoites. This process is essential for parasite survival under unfavorable conditions such as starvation, low temperatures, and exposure to biocides. During encystation, a massive turnover of intracellular components occurs, and a large number of organelles and proteins are degraded by proteases. Previous studies with specific protease inhibitors have shown that cysteine and serine proteases are involved in encystation of Acanthamoeba, but little is known about the role of metalloproteases in this process. Here, we have biochemically characterized an M17 leucine aminopeptidase of Acanthamoeba castellanii (AcLAP) and analyzed its functional involvement in encystation of the parasite. Recombinant AcLAP shared biochemical properties such as optimal pH, requirement of divalent metal ions for activity, substrate specificity for Leu, and inhibition profile by aminopeptidase inhibitors and metal chelators with other characterized M17 family LAPs. AcLAP was highly expressed at a late stage of encystation and mainly localized in the cytoplasm of A. castellanii. Knockdown of AcLAP using small interfering RNA induced a decrease of LAP activity during encystation, a reduction of mature cyst formation, and the formation of abnormal cyst walls. In summary, these results indicate that AcLAP is a typical M17 family enzyme that plays an essential role during encystation of Acanthamoeba.
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Affiliation(s)
- Yu-Ran Lee
- Department of Parasitology and Tropical Medicine, Kyungpook National University School of Medicine, Daegu 700–422, Republic of Korea
| | - Byoung-Kuk Na
- Department of Parasitology and Tropical Medicine, and Institute of Health Sciences, Gyeongsang National University School of Medicine, Jinju 660–751, Republic of Korea
| | - Eun-Kyung Moon
- Department of Parasitology and Tropical Medicine, Kyungpook National University School of Medicine, Daegu 700–422, Republic of Korea
| | - Su-Min Song
- Department of Parasitology and Tropical Medicine, Kyungpook National University School of Medicine, Daegu 700–422, Republic of Korea
| | - So-Young Joo
- Department of Parasitology and Tropical Medicine, Kyungpook National University School of Medicine, Daegu 700–422, Republic of Korea
| | - Hyun-Hee Kong
- Department of Parasitology, Dong-A University, College of Medicine, Busan 602–714, Republic of Korea
| | - Youn-Kyoung Goo
- Department of Parasitology and Tropical Medicine, Kyungpook National University School of Medicine, Daegu 700–422, Republic of Korea
| | - Dong-Il Chung
- Department of Parasitology and Tropical Medicine, Kyungpook National University School of Medicine, Daegu 700–422, Republic of Korea
| | - Yeonchul Hong
- Department of Parasitology and Tropical Medicine, Kyungpook National University School of Medicine, Daegu 700–422, Republic of Korea
- * E-mail:
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Sitting at the window to the world--ocular parasites. Wien Med Wochenschr 2014; 164:392-9. [PMID: 25358598 DOI: 10.1007/s10354-014-0309-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2013] [Accepted: 08/20/2014] [Indexed: 02/02/2023]
Abstract
Parasitic infections cause significant ophthalmic disease, both in developing countries and in the Western world. The parasitic infections Acanthamoeba keratitis, ocular toxoplasmosis, and ocular toxocariasis are responsible for a significant proportion of ocular pathology. Especially in light of the recent increase of immunocompromised (i.e. using immunosuppressants or HIV) and aged populations, parasitic infections of the eye are rising in number. This reviews aims to describe the pathogenesis, symptoms, diagnosis and management of infection, as well as preventative measures for these three parasitic ocular diseases.
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Nowak B, Valdenegro-Vega V, Crosbie P, Bridle A. Immunity to amoeba. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2014; 43:257-267. [PMID: 23921258 DOI: 10.1016/j.dci.2013.07.021] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2013] [Revised: 07/02/2013] [Accepted: 07/28/2013] [Indexed: 06/02/2023]
Abstract
Amoebic infections in fish are most likely underestimated and sometimes overlooked due to the challenges associated with their diagnosis. Amoebic diseases reported in fish affect either gills or internal organs or may be systemic. Host response ranges from hyperplastic response in gill infections to inflammation (including granuloma formation) in internal organs. This review focuses on the immune response of Atlantic salmon to Neoparamoeba perurans, the causative agent of Amoebic Gill Disease (AGD).
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Affiliation(s)
- Barbara Nowak
- NCMCRS, AMC, University of Tasmania, Launceston, Tasmania, Australia.
| | | | - Philip Crosbie
- NCMCRS, AMC, University of Tasmania, Launceston, Tasmania, Australia
| | - Andrew Bridle
- NCMCRS, AMC, University of Tasmania, Launceston, Tasmania, Australia
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Cytotoxic effect of organic solvents and surfactant agents on Acanthamoeba castellanii cysts. Parasitol Res 2014; 113:1949-53. [DOI: 10.1007/s00436-014-3845-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2014] [Accepted: 02/27/2014] [Indexed: 10/25/2022]
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Sun Y, Hong J, Zhang P, Peng R, Xiao G. Pathological characteristics of the different stages ofAcanthamoebakeratitis. Histopathology 2013; 63:862-8. [PMID: 24079482 DOI: 10.1111/his.12237] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2013] [Accepted: 07/21/2013] [Indexed: 11/27/2022]
Affiliation(s)
- Yuzhao Sun
- Department of Ophthalmology; China Medical University; the First Affiliated Hospital; Shenyang China
| | - Jing Hong
- Peking University Third Hospital; Peking University Eye Centre; Beijing China
| | - Pei Zhang
- Peking University Third Hospital; Peking University Eye Centre; Beijing China
| | - Rongmei Peng
- Peking University Third Hospital; Peking University Eye Centre; Beijing China
| | - Gege Xiao
- Peking University Third Hospital; Peking University Eye Centre; Beijing China
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Omaña-Molina M, González-Robles A, Iliana Salazar-Villatoro L, Lorenzo-Morales J, Cristóbal-Ramos AR, Hernández-Ramírez VI, Talamás-Rohana P, Méndez Cruz AR, Martínez-Palomo A. Reevaluating the role of Acanthamoeba proteases in tissue invasion: observation of cytopathogenic mechanisms on MDCK cell monolayers and hamster corneal cells. BIOMED RESEARCH INTERNATIONAL 2013; 2013:461329. [PMID: 23484119 PMCID: PMC3581277 DOI: 10.1155/2013/461329] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/22/2012] [Revised: 12/04/2012] [Accepted: 12/07/2012] [Indexed: 11/25/2022]
Abstract
The morphological analysis of the cytopathic effect on MDCK cell monolayers and hamster cornea and qualitative and quantitative analyses of conditioned medium and proteases were evaluated and compared between two strains of Acanthamoeba genotype T4. Further than highlighting the biological differences found between both strains, the most important observation in this study was the fact that proteases both in total extracts and in conditioned medium are apparently not determinant in tissue destruction. An interestingly finding was that no lysis of corneal tissue was observed as it was previously suggested. These results, together with previous studies, allow us to conclude that the invasion and disruption of corneal tissue is performed by the penetration of the amoebae through cell junctions, either by the action of proteases promoting cellular separation but not by their destruction and/or a mechanical effect exerted by amoebae. Therefore, contact-dependent mechanisms in Acanthamoeba pathogenesis are more relevant than it has been previously considered. This is supported because the phagocytosis of recently detached cells as well as those attached to the corneal epithelium leads to the modification of the cellular architecture facilitating the migration and destruction of deeper layers of the corneal epithelium.
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Affiliation(s)
- Maritza Omaña-Molina
- UIICSE Faculty of Superior Studies Iztacala, Medicine, UNAM, Los Reyes Iztacala, 54090 Tlalnepantla, MEX, Mexico.
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Edwards-Smallbone J, Pleass RJ, Khan NA, Flynn RJ. Acanthamoeba interactions with the blood–brain barrier under dynamic fluid flow. Exp Parasitol 2012; 132:367-72. [DOI: 10.1016/j.exppara.2012.08.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2012] [Revised: 08/14/2012] [Accepted: 08/20/2012] [Indexed: 10/27/2022]
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Kim JH, Matin A, Shin HJ, Park H, Yoo KT, Yuan XZ, Kim KS, Jung SY. Functional roles of mannose-binding protein in the adhesion, cytotoxicity and phagocytosis of Acanthamoeba castellanii. Exp Parasitol 2012; 132:287-92. [DOI: 10.1016/j.exppara.2012.08.007] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2012] [Revised: 07/30/2012] [Accepted: 08/01/2012] [Indexed: 10/28/2022]
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Siddiqui R, Iqbal J, Maugueret MJ, Khan NA. The role of Src kinase in the biology and pathogenesis of Acanthamoeba castellanii. Parasit Vectors 2012; 5:112. [PMID: 22676352 PMCID: PMC3431265 DOI: 10.1186/1756-3305-5-112] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2012] [Accepted: 05/15/2012] [Indexed: 12/02/2022] Open
Abstract
Background Acanthamoeba species are the causative agents of fatal granulomatous encephalitis in humans. Haematogenous spread is thought to be a primary step, followed by blood–brain barrier penetration, in the transmission of Acanthmaoeba into the central nervous system, but the associated molecular mechanisms remain unclear. Here, we evaluated the role of Src, a non-receptor protein tyrosine kinase in the biology and pathogenesis of Acanthamoeba. Methods Amoebistatic and amoebicidal assays were performed by incubating amoeba in the presence of Src kinase-selective inhibitor, PP2 (4-amino-5-(4-chlorophenyl)-7-(t-butyl)pyrazolo[3,4-d]pyrimidine) and its inactive analog, PP3 (4-amino-7-phenylpyrazolo[3,4-d]pyrimidine). Using this inhibitor, the role of Src kinase in A. castellanii interactions with Escherichia coli was determined. Zymographic assays were performed to study effects of Src kinase on extracellular proteolytic activities of A. castellanii. The human brain microvascular endothelial cells were used to determine the effects of Src kinase on A. castellanii adhesion to and cytotoxicity of host cells. Results Inhibition of Src kinase using a specific inhibitor, PP2 (4-amino-5-(4 chlorophenyl)-7-(t-butyl)pyrazolo [3,4-d] pyrimidine) but not its inactive analog, PP3 (4-amino-7-phenylpyrazolo[3,4-d] pyrimidine), had detrimental effects on the growth of A. castellanii (keratitis isolate, belonging to the T4 genotype). Interestingly, inhibition of Src kinase hampered the phagocytic ability of A. castellanii, as measured by the uptake of non-invasive bacteria, but, on the contrary, invasion by pathogenic bacteria was enhanced. Zymographic assays revealed that inhibition of Src kinases reduced extracellular protease activities of A. castellanii. Src kinase inhibition had no significant effect on A. castellanii binding to and cytotoxicity of primary human brain microvascular endothelial cells, which constitute the blood–brain barrier. Conclusions For the first time, these findings demonstrated that Src kinase is involved in A. castellanii proliferation, protease secretions and phagocytic properties. Conversely, invasion of Acanthamoeba by pathogenic bacteria was stimulated by Src kinase inhibition.
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Affiliation(s)
- Ruqaiyyah Siddiqui
- Department of Biological and Biomedical Sciences, The Aga Khan University, Karachi, Pakistan
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Siddiqui R, Emes R, Elsheikha H, Khan NA. Area 51: How do Acanthamoeba invade the central nervous system? Trends Parasitol 2011; 27:185-9. [DOI: 10.1016/j.pt.2011.01.005] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2010] [Revised: 01/16/2011] [Accepted: 01/19/2011] [Indexed: 11/30/2022]
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Acanthamoeba spp.: In vitro effects of clinical isolates on murine macrophages, osteosarcoma and HeLa cells. Exp Parasitol 2010; 126:85-8. [DOI: 10.1016/j.exppara.2009.10.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2009] [Revised: 10/20/2009] [Accepted: 10/21/2009] [Indexed: 11/21/2022]
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Acanthamoeba castellanii: Morphological analysis of the interaction with human cornea. Exp Parasitol 2010; 126:73-8. [DOI: 10.1016/j.exppara.2010.02.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2009] [Revised: 02/02/2010] [Accepted: 02/04/2010] [Indexed: 11/23/2022]
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Rocha-Azevedo BD, Jamerson M, Cabral GA, Marciano-Cabral F. Acanthamoeba culbertsoni: Analysis of amoebic adhesion and invasion on extracellular matrix components collagen I and laminin-1. Exp Parasitol 2010; 126:79-84. [DOI: 10.1016/j.exppara.2009.08.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2009] [Revised: 08/12/2009] [Accepted: 08/14/2009] [Indexed: 11/28/2022]
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Acanthamoeba culbertsoni elicits soluble factors that exert anti-microglial cell activity. Infect Immun 2010; 78:4001-11. [PMID: 20605979 DOI: 10.1128/iai.00047-10] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Acanthamoeba culbertsoni is an opportunistic pathogen that causes granulomatous amoebic encephalitis (GAE), a chronic and often fatal disease of the central nervous system (CNS). A hallmark of GAE is the formation of granulomas around the amoebae. These cellular aggregates consist of microglia, macrophages, lymphocytes, and neutrophils, which produce a myriad of proinflammatory soluble factors. In the present study, it is demonstrated that A. culbertsoni secretes serine peptidases that degrade chemokines and cytokines produced by a mouse microglial cell line (BV-2 cells). Furthermore, soluble factors present in cocultures of A. culbertsoni and BV-2 cells, as well as in cocultures of A. culbertsoni and primary neonatal rat cerebral cortex microglia, induced apoptosis of these macrophage-like cells. Collectively, the results indicate that A. culbertsoni can apply a multiplicity of cell contact-independent modes to target macrophage-like cells that exert antiamoeba activities in the CNS.
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Abstract
Acanthamoeba keratitis (AK) is a serious infection of the cornea. At present, diagnosis of the disease is not straightforward and treatment is very demanding. While contact lens wear is the leading risk factor for A K, Acanthamoeba parasites are increasingly recognized as an important cause of keratitis in non-contact lens wearers. The first critical step in the pathogenesis of infection is the adhesion of the microbe to the surface of the host tissues. Acanthamoebae express a major virulence protein, the mannose-binding protein (MBP), which mediates the adhesion of amoebae to the surface of the cornea. The MBP is a transmembrane protein with characteristics of a typical cell surface receptor. Subsequent to the MBP-mediated adhesion to host cells, the amoebae produce a contact-dependent metalloproteinase and several contact-independent serine proteinases. These proteinases work in concert to produce a potent cytopathic effect (CPE ) involving killing of the host cells, degradation of epithelial basement membrane and underlying stromal matrix, and penetration into the deeper layers of the cornea. In the hamster animal model, oral immunization with the recombinant MBP protects against AK, and this protection is associated with an increased level of anti-MBP IgA in tears of protected animals. Normal human tear fluid contains IgA antibodies against Acanthamoeba MBP that is likely to provide protection by inhibiting the adhesion of parasites to host cells. Indeed, in in vitro CPE assays, even a low concentration of tears (10 microL of undiluted tears per milliliter of media) almost completely inhibits Acanthamoeba-induced CPE . In addition to adherence-inhibiting, IgA-mediated protection, human tears also contain IgA-independent factors that provide protection against Acanthamoeba-induced CPE by inhibiting the activity of cytotoxic proteinases. Characterization of the CPE-inhibitory factors of human tears should lead to a better understanding of the mechanism by which the tissues of the host resist the infection and also help decode circumstances that predispose to Acanthamoeba infections.
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Affiliation(s)
- Noorjahan Panjwani
- Departments of Ophthalmology and Biochemistry, The New England Eye Center, Tufts University School of Medicine, Boston, Massachusetts, USA.
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Ferreira GA, Magliano AC, Pral EM, Alfieri SC. Elastase secretion in Acanthamoeba polyphaga. Acta Trop 2009; 112:156-63. [PMID: 19632188 DOI: 10.1016/j.actatropica.2009.07.015] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2008] [Revised: 05/20/2009] [Accepted: 07/18/2009] [Indexed: 10/20/2022]
Abstract
Acanthamoeba species are frequently isolated from soil and water collections. In the environment, the organisms multiply as phagotrophic trophozoites and encyst under adverse conditions. Several species are known to infect man, causing keratitis and opportunistic diseases. The mechanisms underlying tissue damage and invasion by the amoebae are being elucidated and the involvement of secreted peptidases, particularly serine peptidases, has been demonstrated. Here, elastase activity was examined in Acanthamoeba-conditioned medium (ACM), making use of elastin-Congo red (ECR) and synthetic peptide p-nitroanilide substrates. ACM hydrolysed ECR over a broad pH range and optimally at a pH of 7.5 and above. Indicating the activity of serine and metallopeptidases, Congo red release was potently inhibited by PMSF, antipain, chymostatin and 1,10-phenanthroline, partially reduced by elastatinal and EDTA, and unaffected by 1,7-phenanthroline and E-64. Screening with synthetic substrates mainly showed the activity of serine peptidases. ACM efficiently hydrolysed Suc-Ala(2)-Pro-Leu-pNA and Suc-Ala(2)-Pro-Phe-pNA over a broad pH range (7.0-9.5) and was weakly active against Suc-Ala(3)-pNA, a substrate found to be optimally hydrolysed at a pH around 7.0. Following ammonium sulfate precipitation of ACM proteins and FPLC analysis, the majority of the ECR-splitting activity, characterised as serine peptidases, bound to CM-sepharose and co-eluted with part of the Suc-Ala(2)-Pro-Phe-pNA-hydrolysing activity in a gradient of 0-0.6M NaCl. In the corresponding FPLC fractions, serine peptidases resolving in the region of 70-130kDa were detected in gelatin gels. Overall, the results demonstrate that trophozoites secrete elastases, and additionally suggest the high molecular weight serine peptidases as possible elastase candidates.
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Lau HY, Ashbolt NJ. The role of biofilms and protozoa in Legionella pathogenesis: implications for drinking water. J Appl Microbiol 2009; 107:368-78. [PMID: 19302312 DOI: 10.1111/j.1365-2672.2009.04208.x] [Citation(s) in RCA: 186] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Current models to study Legionella pathogenesis include the use of primary macrophages and monocyte cell lines, various free-living protozoan species and murine models of pneumonia. However, there are very few studies of Legionella spp. pathogenesis aimed at associating the role of biofilm colonization and parasitization of biofilm microbiota and release of virulent bacterial cell/vacuoles in drinking water distribution systems. Moreover, the implications of these environmental niches for drinking water exposure to pathogenic legionellae are poorly understood. This review summarizes the known mechanisms of Legionella spp. proliferation within Acanthamoeba and mammalian cells and advocates the use of the amoeba model to study Legionella pathogenicity because of their close association with Legionella spp. in the aquatic environment. The putative role of biofilms and amoebae in the proliferation, development and dissemination of potentially pathogenic Legionella spp. is also discussed. Elucidating the mechanisms of Legionella pathogenicity development in our drinking water systems will aid in elimination strategies and procedural designs for drinking water systems and in controlling exposure to Legionella spp. and similar pathogens.
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Affiliation(s)
- H Y Lau
- National Exposure Research Laboratory, U.S. Environmental Protection Agency, Cincinnati, OH 45268, USA.
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In vitro activity of Acanthamoeba castellanii on human platelets and erythrocytes. Infect Immun 2008; 77:733-8. [PMID: 19015256 DOI: 10.1128/iai.00202-08] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The effect of Acanthamoeba on human platelets and erythrocytes has not been fully elucidated. This paper reports that cell-free supernatants prepared from A. castellanii can activate human platelets, causing both a significant increase in the cytosolic free-calcium concentration and platelet aggregation. In addition, we demonstrated that platelet activation depends on the activity of ADP constitutively secreted into the medium by trophozoites. This study also showed that A. castellanii can affect human red blood cells, causing hemolysis, and provided evidence that hemolysis occurs in both contact-dependent and contact-independent ways; there are differences in kinetics, hemolytic activity, and calcium dependency between the contact-dependent and contact-independent mechanisms. Partial characterization of contact-independent hemolysis indicated that ADP does not affect the plasma membrane permeability of erythrocytes and that heat treatment of amoebic cell-free supernatant abolishes its hemolytic activity. These findings suggest that some heat-labile molecules released by A. castellanii trophozoites are involved in this phenomenon. Finally, our data suggest that human platelets and erythrocytes may be potential cell targets during Acanthamoeba infection.
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Tan TC, Suresh KG, Smith HV. Phenotypic and genotypic characterisation of Blastocystis hominis isolates implicates subtype 3 as a subtype with pathogenic potential. Parasitol Res 2008; 104:85-93. [PMID: 18795333 DOI: 10.1007/s00436-008-1163-5] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2008] [Accepted: 08/13/2008] [Indexed: 11/24/2022]
Abstract
Despite frequent reports on the presence of Blastocystis hominis in human intestinal tract, its pathogenicity remains a matter of intense debate. These discrepancies may be due to the varying pathogenic potential or virulence of the isolates studied. The present study represents the first to investigate both phenotypic and genotypic characteristics of B. hominis obtained from symptomatic and asymptomatic individuals. Symptomatic isolates had a significantly greater size range and lower growth rate in Jones' medium than asymptomatic isolates. The parasite cells of symptomatic isolates exhibited rougher surface topography and greater binding affinity to Canavalia ensiformis (ConA) and Helix pomatia (HPA). The present study also identifies further phenotypic characteristics, which aided in differentiating the pathogenic forms from the non-pathogenic forms of B. hominis. Blastocystis subtype 3 was found to be correlated well with the disease.
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Affiliation(s)
- T C Tan
- Department of Parasitology, University of Malaya, Kuala Lumpur, Malaysia
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Alizadeh H, Li H, Neelam S, Niederkorn JY. Modulation of corneal and stromal matrix metalloproteinase by the mannose-induced Acanthamoeba cytolytic protein. Exp Eye Res 2008; 87:286-91. [PMID: 18627771 DOI: 10.1016/j.exer.2008.06.011] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2008] [Accepted: 06/17/2008] [Indexed: 11/18/2022]
Abstract
The involvement of the mannose-induced Acanthamoeba cytopathic protein (MIP-133) in tissue injury and activation of metalloproteinase of corneal and stromal cells was examined in vitro. Activation of MMP-1, MMP-2, MMP-3, and MMP-9 induced by MIP-133 on human corneal epithelial and stromal cell cultures was examined by reverse transcriptase polymerase chain reaction (RT-PCR) and ELISA. MMP-1, MMP-2, MMP-3, and MMP-9 mRNA were expressed in both cultured human corneal epithelial and stromal cells. When the epithelial cells were exposed to MIP-133 protein, the mRNA expression for MMP-1 and MMP-9 was unchanged. However, the transcript for MMP-2 and MMP-3 was decreased by 2-fold. By contrast, the expression of MMP-2 and MMP-3 was significantly upregulated (2- to 4-fold) in the corneal stromal cells 1, 4, and 8h after MIP-133 stimulation. At the protein level, there was no significant difference in the level of MMPs between the corneal epithelial cells before and after stimulation with MIP-133. By contrast, the levels of MMP-2 and MMP-3 were significantly higher in the corneal stromal cells stimulated with MIP-133. The supernatants from corneal stromal cells stimulated with MIP-133 were incubated with PMSF and MIP-133 antibody and the level of MMP-2 was measured by ELISA. Activation of MMP-2 by MIP-133 was inhibited in the supernatants pretreated with the serine protease inhibitor, PMSF, and anti-MIP-133. Supernatants pretreated with the cysteine protease inhibitor E6 or control antibody produced the same amount of MMP-2 as the untreated supernatants. To verify possible homology between MMPs and Acanthamoeba castellanii proteases, the mRNA from A. castellanii was prepared and analyzed for the expression of MMP genes by PT-PCR. The results showed that A. castellanii did not express mRNA for MMP-1, MMP-2, MMP-3, or MMP-9. Thus, A. castellanii mRNA does not cross-react with human MMPs. Furthermore, ELISA was used to determine the cross-reactivity of MMP antibodies with the MIP-133 protein. Monoclonal antibodies against MMPs did not cross-react with either the MIP-133 protein or BSA (negative control antigen). The results indicate that the MIP-133 protein modulates MMP-2 and -3 expression differently in human corneal epithelial and stromal cells.
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Affiliation(s)
- Hassan Alizadeh
- Department of Ophthalmology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9057, USA.
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Ohlsen K, Oelschlaeger TA, Hacker J, Khan AS. Carbohydrate receptors of bacterial adhesins: implications and reflections. Top Curr Chem (Cham) 2008; 288:17-65. [PMID: 22328026 DOI: 10.1007/128_2008_10] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Bacteria entering a host depend on adhesins to achieve colonization. Adhesins are bacterial surface structures mediating binding to host surficial areas. Most adhesins are composed of one or several proteins. Usually a single bacterial strain is able to express various adhesins. The adhesion type expressed may influence host-, tissue or even cell tropism of Gram-negative and of Gram-positive bacteria. The binding of fimbrial as well as of afimbrial adhesins of Gram-negative bacteria to host carbohydrate structures (=receptors) has been elucidated in great detail. In contrast, in Gram-positives, most well studied adhesins bind to proteinaceous partners. Nevertheless, for both bacterial groups the binding of bacterial adhesins to eukaryotic carbohydrate receptors is essential for establishing colonization or infection. The characterization of this interaction down to the submolecular level provides the basis for strategies to interfere with this early step of infection which should lead to the prevention of subsequent disease. However, this goal will not be achieved easily because bacterial adherence is not a monocausal event but rather mediated by a variety of adhesins.
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Affiliation(s)
- K Ohlsen
- Institut für Molekulare Infektionsbiologie, Röntgenring 11, 97070, Würzburg
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Williamson YM, Gowrisankar R, Longo DL, Facklam R, Gipson IK, Ades EP, Carlone GM, Sampson JS. Adherence of nontypeable Streptococcus pneumoniae to human conjunctival epithelial cells. Microb Pathog 2007; 44:175-85. [PMID: 17936571 DOI: 10.1016/j.micpath.2007.08.016] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2007] [Revised: 08/21/2007] [Accepted: 08/31/2007] [Indexed: 11/26/2022]
Abstract
Conjunctivitis outbreaks have occurred in the US in which nontypeable (NT) Streptococcus pneumoniae (Pnc) strains have been identified as the etiologic agent; however, the pathogenesis of Pnc conjunctivitis has not been extensively evaluated. Here we assessed the adhesive and invasive properties of 13 NT US conjunctivitis outbreak strains (cPnc) using an immortalized human conjunctival epithelial cell (HCjE) line expressing high or low levels of mucin as a surrogate for in vivo ocular surface events. Studies reveal differential binding efficiencies (up to 18-fold) among cPnc strains to HCjE cells and reduced or little adherence efficiency to high mucin-expressing (HME-HCjE). Additionally, in the presence of exogenous mucin there is considerable inhibition (20% to approximately 100%) of bacterial binding to the HCjE cells. Invasion assays suggest that the cPnc are internalized in HCjE, and less in HME-HCjE cells. Microarray analysis of cPnc isolates revealed an up-regulation of Pnc neuraminidases, and treatment of HME-HCjE cells with exogenous neuraminidase resulted in a 2-13-fold enhancement in cPnc binding. The results indicate that mucin acts as a protective barrier in vitro and that neuraminidases, which can degrade mucin, may be contributing factors leading to bacterial adherence, a first step in the pathogenesis of this transmissible infection.
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Affiliation(s)
- Yulanda M Williamson
- Centers for Disease Control and Prevention, 1600 Clifton Road, NE, Building 18, B-133, MS-G5, Atlanta, GA 30333, USA
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Declerck P, Behets J, De Keersmaecker B, Ollevier F. Receptor-mediated uptake of Legionella pneumophila by Acanthamoeba castellanii and Naegleria lovaniensis. J Appl Microbiol 2007; 103:2697-703. [PMID: 17850297 DOI: 10.1111/j.1365-2672.2007.03530.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
AIMS Investigation of the attachment and uptake of Legionella pneumophila by Acanthamoeba castellanii and Naegleria lovaniensis, as these are two critical steps in the subsequent bacterial survival in both amoeba hosts. METHODS AND RESULTS Initially, the mode of Legionella uptake was examined using inhibitors of microfilament-dependent and receptor-mediated uptake phagocytosis. Secondly, the minimum saccharide structure to interfere with L. pneumophila uptake was determined by means of selected saccharides. Bacterial attachment and uptake by each of the amoeba species occurred through a receptor-mediated endocytosis, which required de novo synthesis of host proteins. Legionella pneumophila showed a high affinity to the alpha1-3D-mannobiose domain of the mannose-binding receptor located on A. castellanii. In contrast, L. pneumophila bacteria had a high affinity for the GalNAcbeta1-4Gal domain of the N-acetyl-D-galactosamine receptor of N. lovaniensis. CONCLUSIONS Our data pointed to a remarkable adaptation of L. pneumophila to invade different amoeba hosts, as the uptake by both amoeba species is mediated by two different receptor families. SIGNIFICANCE AND IMPACT OF THE STUDY The fact that L. pneumophila is taken up by two different amoeba species using different receptor families adds further complexity to the host-parasite interaction process, as 14 amoeba species are known to be appropriate Legionella hosts.
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Affiliation(s)
- P Declerck
- Laboratory of Aquatic Ecology, Zoological Institute, Katholieke Universiteit Leuven, Leuven, Belgium.
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da Rocha-Azevedo B, Costa e Silva-Filho F. Biological characterization of a clinical and an environmental isolate of Acanthamoeba polyphaga: analysis of relevant parameters to decode pathogenicity. Arch Microbiol 2007; 188:441-9. [PMID: 17569030 DOI: 10.1007/s00203-007-0264-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2006] [Revised: 02/22/2007] [Accepted: 05/20/2007] [Indexed: 11/25/2022]
Abstract
Acanthamoeba spp. consists of free-living amoebae, widespread in nature, which occasionally can cause human infections including granulomatous amoebic encephalitis and amoebic keratitis. Acanthamoeba pathogenesis is not entirely known and correlations between pathogenic potential and taxonomy are complex issues. In order to decipher the definition of a pathogenic amoeba, the objective of this work was to decipher the definition of pathogenic amoeba by characterizing two isolates of Acanthamoeba polyphaga obtained from different origins (a keratitis patient and freshwater), looking for differences among them. The clinical isolate grew faster in Peptone-yeast extract-glucose (PYG) medium, transformed more rapidly from a trophozoite to cyst and exhibited increased cytopathic effect on cultured cells. Morphological differences were also noted, since freshwater amoebae presented more acanthopodia than the clinical isolate. Moreover, actin labeling demonstrated that microfilament organization varies between isolates, with the presence of locomotory structures as lobopodia and lamellipodia in the keratitis isolate, which were less adherent on plastic. Zymography demonstrated that the keratitis isolates presented higher proteolytic activity and also were more able to invade collagen matrices. Altogether, we conclude that a group of stable physiological characteristics exist in Acanthamoeba that can be related to pathogenicity.
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Affiliation(s)
- Bruno da Rocha-Azevedo
- Programa de Bioengenharia e Biotecnologia Animal, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, UFRJ-CCS, bloco G, sala G0-044, Cidade Universitária, Ilha do Fundão, Rio de Janeiro, RJ, CEP 21949-900, Brazil
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