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Barrios AA, Mouhape C, Schreiber L, Zhang L, Nell J, Suárez-Martins M, Schlapp G, Meikle MN, Mulet AP, Hsu TL, Hsieh SL, Mourglia-Ettlin G, González C, Crispo M, Barth TFE, Casaravilla C, Jenkins SJ, Díaz Á. Mucins Shed from the Laminated Layer in Cystic Echinococcosis Are Captured by Kupffer Cells via the Lectin Receptor Clec4F. Infect Immun 2023; 91:e0003123. [PMID: 37162364 PMCID: PMC10269144 DOI: 10.1128/iai.00031-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Accepted: 04/17/2023] [Indexed: 05/11/2023] Open
Abstract
Cystic echinococcosis is caused by the larval stages (hydatids) of cestode parasites belonging to the species cluster Echinococcus granulosus sensu lato, with E. granulosus sensu stricto being the main infecting species. Hydatids are bladderlike structures that attain large sizes within various internal organs of livestock ungulates and humans. Hydatids are protected by the massive acellular laminated layer (LL), composed mainly of mucins. Parasite growth requires LL turnover, and abundant LL-derived particles are found at infection sites in infected humans, raising the question of how LL materials are dealt with by the hosts. In this article, we show that E. granulosus sensu stricto LL mucins injected into mice are taken up by Kupffer cells, the liver macrophages exposed to the vascular space. This uptake is largely dependent on the intact mucin glycans and on Clec4F, a C-type lectin receptor which, in rodents, is selectively expressed in Kupffer cells. This uptake mechanism operates on mucins injected both in soluble form intravenously (i.v.) and in particulate form intraperitoneally (i.p.). In mice harboring intraperitoneal infections by the same species, LL mucins were found essentially only at the infection site and in the liver, where they were taken up by Kupffer cells via Clec4F. Therefore, shed LL materials circulate in the host, and Kupffer cells can act as a sink for these materials, even when the parasite grows in sites other than the liver.
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Affiliation(s)
- Anabella A. Barrios
- Área Inmunología, Departamento de Biociencias (Facultad de Química) and Cátedra de Inmunología, Instituto de Química Biológica (Facultad de Ciencias), Universidad de la República, Montevideo, Uruguay
| | - Camila Mouhape
- Área Inmunología, Departamento de Biociencias (Facultad de Química) and Cátedra de Inmunología, Instituto de Química Biológica (Facultad de Ciencias), Universidad de la República, Montevideo, Uruguay
| | | | - Linyun Zhang
- Institute of Pathology, University Ulm, Ulm, Germany
| | - Juliane Nell
- Institute of Pathology, University Ulm, Ulm, Germany
| | - Mariana Suárez-Martins
- Área Inmunología, Departamento de Biociencias (Facultad de Química) and Cátedra de Inmunología, Instituto de Química Biológica (Facultad de Ciencias), Universidad de la República, Montevideo, Uruguay
| | - Geraldine Schlapp
- Unidad de Biotecnología en Animales de Laboratorio, Institut Pasteur de Montevideo, Montevideo, Uruguay
| | - María Noel Meikle
- Unidad de Biotecnología en Animales de Laboratorio, Institut Pasteur de Montevideo, Montevideo, Uruguay
| | - Ana Paula Mulet
- Unidad de Biotecnología en Animales de Laboratorio, Institut Pasteur de Montevideo, Montevideo, Uruguay
| | - Tsui-Ling Hsu
- Genomics Research Center, Academia Sinica, Taipei, Taiwan
| | | | - Gustavo Mourglia-Ettlin
- Área Inmunología, Departamento de Biociencias (Facultad de Química) and Cátedra de Inmunología, Instituto de Química Biológica (Facultad de Ciencias), Universidad de la República, Montevideo, Uruguay
| | | | - Martina Crispo
- Unidad de Biotecnología en Animales de Laboratorio, Institut Pasteur de Montevideo, Montevideo, Uruguay
| | | | - Cecilia Casaravilla
- Área Inmunología, Departamento de Biociencias (Facultad de Química) and Cátedra de Inmunología, Instituto de Química Biológica (Facultad de Ciencias), Universidad de la República, Montevideo, Uruguay
| | - Stephen J. Jenkins
- University of Edinburgh Centre for Inflammation Research, Queen's Medical Research Institute, University of Edinburgh, Edinburgh, United Kingdom
| | - Álvaro Díaz
- Área Inmunología, Departamento de Biociencias (Facultad de Química) and Cátedra de Inmunología, Instituto de Química Biológica (Facultad de Ciencias), Universidad de la República, Montevideo, Uruguay
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Díaz Á, Barrios AA, Grezzi L, Mouhape C, Jenkins SJ, Allen JE, Casaravilla C. Immunology of a unique biological structure: the Echinococcus laminated layer. Protein Cell 2023; 14:87-104. [PMID: 36929004 PMCID: PMC10019577 DOI: 10.1093/procel/pwac023] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 04/29/2022] [Accepted: 05/23/2022] [Indexed: 11/13/2022] Open
Abstract
The larval stages of the cestode parasites belonging to the genus Echinococcus grow within internal organs of humans and a range of animal species. The resulting diseases, collectively termed echinococcoses, include major neglected tropical diseases of humans and livestock. Echinococcus larvae are outwardly protected by the laminated layer (LL), an acellular structure that is unique to this genus. The LL is based on a fibrillar meshwork made up of mucins, which are decorated by galactose-rich O-glycans. In addition, in the species cluster termed E. granulosus sensu lato, the LL features nano-deposits of the calcium salt of myo-inositol hexakisphosphate (Insp6). The main purpose of our article is to update the immunobiology of the LL. Major recent advances in this area are (i) the demonstration of LL "debris" at the infection site and draining lymph nodes, (ii) the characterization of the decoy activity of calcium Insp6 with respect to complement, (iii) the evidence that the LL mucin carbohydrates interact specifically with a lectin receptor expressed in Kupffer cells (Clec4F), and (iv) the characterization of what appear to be receptor-independent effects of LL particles on dendritic cells and macrophages. Much information is missing on the immunology of this intriguing structure: we discuss gaps in knowledge and propose possible avenues for research.
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Affiliation(s)
| | - Anabella A Barrios
- Área Inmunología, Departamento de Biociencias (Facultad de Química) and Cátedra de Inmunología, Instituto de Química Biológica (Facultad de Ciencias), Universidad de la República, Montevideo, Uruguay
| | - Leticia Grezzi
- Área Inmunología, Departamento de Biociencias (Facultad de Química) and Cátedra de Inmunología, Instituto de Química Biológica (Facultad de Ciencias), Universidad de la República, Montevideo, Uruguay
| | - Camila Mouhape
- Área Inmunología, Departamento de Biociencias (Facultad de Química) and Cátedra de Inmunología, Instituto de Química Biológica (Facultad de Ciencias), Universidad de la República, Montevideo, Uruguay
| | - Stephen J Jenkins
- Centre for Inflammation Research, Queen’s Medical Research Institute, University of Edinburgh, Edinburgh, EH8 9JU, UK
| | - Judith E Allen
- Lydia Becker Institute of Immunology and Inflammation, School of Biological Sciences, University of Manchester, Manchester Academic Health Sciences Centre, Manchester, M13 9NQ, UK
| | - Cecilia Casaravilla
- Área Inmunología, Departamento de Biociencias (Facultad de Química) and Cátedra de Inmunología, Instituto de Química Biológica (Facultad de Ciencias), Universidad de la República, Montevideo, Uruguay
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Wang N, Zhan J, Guo C, Li C, Shen N, Gu X, Xie Y, Peng X, Yang G. Molecular Characterisation and Functions of Fis1 and PDCD6 Genes from Echinococcus granulosus. Int J Mol Sci 2018; 19:ijms19092669. [PMID: 30205566 PMCID: PMC6165261 DOI: 10.3390/ijms19092669] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2018] [Revised: 08/22/2018] [Accepted: 09/05/2018] [Indexed: 11/16/2022] Open
Abstract
Cystic echinococcosis, a parasitic zoonosis that causes significant economic losses and poses a threat to public health, is caused by larvae of the tapeworm Echinococcus granulosus. Infection causes infertile cysts in intermediate hosts that cannot produce protoscoleces (PSCs) or complete the life cycle. Herein, we cloned, expressed, and characterised mitochondrial fission protein 1 (Eg-Fis1) and programmed cell death protein 6 (Eg-PDCD6) from E. granulosus, and explored their functions related to infertile cysts. Eg-Fis1 and Eg-PDCD6 encode putative 157 and 174 residue proteins, respectively, and Western blotting indicated good reactogenicity for both. Eg-Fis1 and Eg-PDCD6 were ubiquitously distributed in all stages of E. granulosus. Furthermore, mRNAs of Eg-Fis1 and Eg-PDCD6 were upregulated following H2O2 treatment which induced apoptosis in PSCs. To investigate the regulation of apoptosis in response to oxidative stress, RNA interference (RNAi) and terminal deoxynucleotidyl transferase dUTP nick-end labelling (TUNEL) assays were performed. The apoptotic rate of the Eg-Fis1 RNAi group was significantly lower than non-interference group, but there was no such difference for Eg-PDCD6. In conclusion, Eg-Fis1 promotes apoptosis induced by oxidative stress, whereas Eg-PDCD6 does not appear to be a key regulator of apoptosis.
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Affiliation(s)
- Ning Wang
- Department of Parasitology, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, China.
- College of Bioengineering, Sichuan University of Science and Engineering, Yibin 644000, China.
| | - Jiafei Zhan
- Department of Parasitology, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, China.
| | - Cheng Guo
- Department of Parasitology, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, China.
| | - Chunyan Li
- Department of Parasitology, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, China.
| | - Nengxing Shen
- Department of Parasitology, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, China.
| | - Xiaobin Gu
- Department of Parasitology, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, China.
| | - Yue Xie
- Department of Parasitology, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, China.
| | - Xuerong Peng
- Department of Chemistry, College of Life and Basic Science, Sichuan Agricultural University, Chengdu 611130, China.
| | - Guangyou Yang
- Department of Parasitology, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, China.
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Ranasinghe SL, Boyle GM, Fischer K, Potriquet J, Mulvenna JP, McManus DP. Kunitz type protease inhibitor EgKI-1 from the canine tapeworm Echinococcus granulosus as a promising therapeutic against breast cancer. PLoS One 2018; 13:e0200433. [PMID: 30169534 PMCID: PMC6118354 DOI: 10.1371/journal.pone.0200433] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Accepted: 08/06/2018] [Indexed: 12/21/2022] Open
Abstract
EgKI-1, a member of the Kunitz type protease inhibitor family, is highly expressed by the oncosphere of the canine tapeworm Echinococcus granulosus, the stage that is infectious to humans and ungulates, giving rise to a hydatid cyst localized to the liver and other organs. Larval protoscoleces, which develop within the hydatid cyst, have been shown to possess anti-cancer properties, although the precise molecules involved have not been identified. We show that recombinant EgKI-1 inhibits the growth and migration of a range of human cancers including breast, melanoma and cervical cancer cell lines in a dose-dependent manner in vitro without affecting normal cell growth. Furthermore, EgKI-1 treatment arrested the cancer cell growth by disrupting the cell cycle and induced apoptosis of cancer cells in vitro. An in vivo model of triple negative breast cancer (MDA-MB-231) in BALB/c nude mice showed significant tumor growth reduction in EgKI-1-treated mice compared with controls. These findings indicate that EgKI-1 shows promise for future development as an anti-cancer therapeutic.
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Affiliation(s)
- Shiwanthi L. Ranasinghe
- Molecular Parasitology Laboratory, Immunology Department, QIMR Berghofer Medical Research Institute, Brisbane, Australia
- * E-mail:
| | - Glen M. Boyle
- Cancer Drug Mechanisms Group, Cell & Molecular Biology Department, QIMR Berghofer Medical Research Institute, Brisbane, Australia
| | - Katja Fischer
- Scabies Group, Cell & Molecular Biology Department, QIMR Berghofer Medical Research Institute, Brisbane, Australia
| | - Jeremy Potriquet
- Australian Institute of Tropical Health & Medicine, James Cook University, Cairns, Australia
| | - Jason P. Mulvenna
- Biomarkers and Biology of Infection Related Cancers Laboratory, QIMR Berghofer Medical Research Institute, Brisbane, Australia
| | - Donald P. McManus
- Molecular Parasitology Laboratory, Immunology Department, QIMR Berghofer Medical Research Institute, Brisbane, Australia
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Salinas G, Gao W, Wang Y, Bonilla M, Yu L, Novikov A, Virginio VG, Ferreira HB, Vieites M, Gladyshev VN, Gambino D, Dai S. The Enzymatic and Structural Basis for Inhibition of Echinococcus granulosus Thioredoxin Glutathione Reductase by Gold(I). Antioxid Redox Signal 2017; 27:1491-1504. [PMID: 28463568 PMCID: PMC5678357 DOI: 10.1089/ars.2016.6816] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Revised: 04/11/2017] [Accepted: 04/12/2017] [Indexed: 01/04/2023]
Abstract
AIMS New drugs are needed to treat flatworm infections that cause severe human diseases such as schistosomiasis. The unique flatworm enzyme thioredoxin glutathione reductase (TGR), structurally different from the human enzyme, is a key drug target. Structural studies of the flatworm Echinococcus granulosus TGR, free and complexed with AuI-MPO, a novel gold inhibitor, together with inhibition assays were performed. RESULTS AuI-MPO is a potent TGR inhibitor that achieves 75% inhibition at a 1:1 TGR:Au ratio and efficiently kills E. granulosus in vitro. The structures revealed salient insights: (i) unique monomer-monomer interactions, (ii) distinct binding sites for thioredoxin and the glutaredoxin (Grx) domain, (iii) a single glutathione disulfide reduction site in the Grx domain, (iv) rotation of the Grx domain toward the Sec-containing redox active site, and (v) a single gold atom bound to Cys519 and Cys573 in the AuI-TGR complex. Structural modeling suggests that these residues are involved in the stabilization of the Sec-containing C-terminus. Consistently, Cys→Ser mutations in these residues decreased TGR activities. Mass spectroscopy confirmed these cysteines are the primary binding site. INNOVATION The identification of a primary site for gold binding and the structural model provide a basis for gold compound optimization through scaffold adjustments. CONCLUSIONS The structural study revealed that TGR functions are achieved not only through a mobile Sec-containing redox center but also by rotation of the Grx domain and distinct binding sites for Grx domain and thioredoxin. The conserved Cys519 and Cys573 residues targeted by gold assist catalysis through stabilization of the Sec-containing redox center. Antioxid. Redox Signal. 27, 1491-1504.
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Affiliation(s)
- Gustavo Salinas
- Worm Biology Lab, Institut Pasteur de Montevideo, Montevideo, Uruguay
- Cátedra de Inmunología, Facultad de Química, Instituto de Higiene, Universidad de la República, Montevideo, Uruguay
| | - Wei Gao
- Department of Biomedical Research, National Jewish Health, Denver, Colorado
- Department of Immunology and Microbiology, University of Colorado Denver, School of Medicine, Aurora, Colorado
- School of Science, Beijing Forestry University, Beijing, China
| | - Yang Wang
- Department of Biomedical Research, National Jewish Health, Denver, Colorado
- Department of Immunology and Microbiology, University of Colorado Denver, School of Medicine, Aurora, Colorado
| | - Mariana Bonilla
- Cátedra de Inmunología, Facultad de Química, Instituto de Higiene, Universidad de la República, Montevideo, Uruguay
- Redox Biology of Trypanosomes, Institut Pasteur de Montevideo, Uruguay
| | - Long Yu
- Department of Biomedical Research, National Jewish Health, Denver, Colorado
- Department of Immunology and Microbiology, University of Colorado Denver, School of Medicine, Aurora, Colorado
| | - Andrey Novikov
- Department of Biomedical Research, National Jewish Health, Denver, Colorado
- Department of Immunology and Microbiology, University of Colorado Denver, School of Medicine, Aurora, Colorado
| | - Veridiana G. Virginio
- Laboratório de Genômica Estrutural e Funcional, Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Henrique B. Ferreira
- Laboratório de Genômica Estrutural e Funcional, Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Marisol Vieites
- Cátedra de Química Inorgánica, Facultad de Química, Universidad de la República, Montevideo, Uruguay
| | - Vadim N. Gladyshev
- Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Dinorah Gambino
- Cátedra de Química Inorgánica, Facultad de Química, Universidad de la República, Montevideo, Uruguay
| | - Shaodong Dai
- Department of Biomedical Research, National Jewish Health, Denver, Colorado
- Department of Immunology and Microbiology, University of Colorado Denver, School of Medicine, Aurora, Colorado
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Alvite G, Esteves A. Echinococcus granulosus fatty acid binding proteins subcellular localization. Exp Parasitol 2016; 164:1-4. [PMID: 26873273 DOI: 10.1016/j.exppara.2016.02.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2015] [Revised: 02/04/2016] [Accepted: 02/05/2016] [Indexed: 11/19/2022]
Abstract
Two fatty acid binding proteins, EgFABP1 and EgFABP2, were isolated from the parasitic platyhelminth Echinococcus granulosus. These proteins bind fatty acids and have particular relevance in flatworms since de novo fatty acids synthesis is absent. Therefore platyhelminthes depend on the capture and intracellular distribution of host's lipids and fatty acid binding proteins could participate in lipid distribution. To elucidate EgFABP's roles, we investigated their intracellular distribution in the larval stage by a proteomic approach. Our results demonstrated the presence of EgFABP1 isoforms in cytosolic, nuclear, mitochondrial and microsomal fractions, suggesting that these molecules could be involved in several cellular processes.
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Affiliation(s)
- Gabriela Alvite
- Sección Bioquímica, Facultad de Ciencias, Universidad de la República, Iguá 4225, C.P. 11400 Montevideo, Uruguay.
| | - Adriana Esteves
- Sección Bioquímica, Facultad de Ciencias, Universidad de la República, Iguá 4225, C.P. 11400 Montevideo, Uruguay
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Debarba JA, Monteiro KM, Moura H, Barr JR, Ferreira HB, Zaha A. Identification of Newly Synthesized Proteins by Echinococcus granulosus Protoscoleces upon Induction of Strobilation. PLoS Negl Trop Dis 2015; 9:e0004085. [PMID: 26393918 PMCID: PMC4578768 DOI: 10.1371/journal.pntd.0004085] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Accepted: 08/25/2015] [Indexed: 12/21/2022] Open
Abstract
Background The proteins responsible for the key molecular events leading to the structural changes between the developmental stages of Echinococcus granulosus remain unknown. In this work, azidohomoalanine (AHA)-specific labeling was used to identify proteins expressed by E. granulosus protoscoleces (PSCs) upon the induction of strobilar development. Methodology/Principal Findings The in vitro incorporation of AHA with different tags into newly synthesized proteins (NSPs) by PSCs was analyzed using SDS-PAGE and confocal microscopy. The LC-MS/MS analysis of AHA-labeled NSPs by PSCs undergoing strobilation allowed for the identification of 365 proteins, of which 75 were differentially expressed in comparison between the presence or absence of strobilation stimuli and 51 were expressed exclusively in either condition. These proteins were mainly involved in metabolic, regulatory and signaling processes. Conclusions/Significance After the controlled-labeling of proteins during the induction of strobilar development, we identified modifications in protein expression. The changes in the metabolism and the activation of control and signaling pathways may be important for the correct parasite development and be target for further studies. In the life cycle of the parasite Echinococcus granulosus, hydatid cysts produce the pre-adult form, which has the ability to either differentiate into an adult worm (strobilation) or dedifferentiate into a secondary hydatid cyst. We used different protein tags that allowed for the visualization and purification of proteins produced specifically after the induction of strobilar development to identify proteins that might be involved in this process (temporally controlled and context-dependent). As a result, we found proteins that are involved in important processes during development, such as energy metabolism, control pathways and cellular communication. We believe that these results will be useful for the development of scientific approaches to controlling and preventing cystic hydatid disease.
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Affiliation(s)
- João Antonio Debarba
- Programa de Pós-Graduação em Biologia Celular e Molecular, Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Rio Grande do Sul, Brazil
- Laboratório de Biologia Molecular de Cestódeos, and Laboratório de Genômica Estrutural e Funcional, Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Rio Grande do Sul, Brazil
| | - Karina Mariante Monteiro
- Programa de Pós-Graduação em Biologia Celular e Molecular, Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Rio Grande do Sul, Brazil
- Laboratório de Biologia Molecular de Cestódeos, and Laboratório de Genômica Estrutural e Funcional, Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Rio Grande do Sul, Brazil
- Departamento de Biologia Molecular e Biotecnologia, Instituto de Biociências, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Hercules Moura
- Biological Mass Spectrometry Laboratory, Clinical Chemistry Branch, Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - John R. Barr
- Biological Mass Spectrometry Laboratory, Clinical Chemistry Branch, Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Henrique Bunselmeyer Ferreira
- Programa de Pós-Graduação em Biologia Celular e Molecular, Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Rio Grande do Sul, Brazil
- Laboratório de Biologia Molecular de Cestódeos, and Laboratório de Genômica Estrutural e Funcional, Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Rio Grande do Sul, Brazil
- Departamento de Biologia Molecular e Biotecnologia, Instituto de Biociências, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Arnaldo Zaha
- Programa de Pós-Graduação em Biologia Celular e Molecular, Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Rio Grande do Sul, Brazil
- Laboratório de Biologia Molecular de Cestódeos, and Laboratório de Genômica Estrutural e Funcional, Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Rio Grande do Sul, Brazil
- Departamento de Biologia Molecular e Biotecnologia, Instituto de Biociências, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
- * E-mail:
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Zhang T, Jia LF, Chen Y, Ju C, Mo XJ, Xu B, Chen SB, Chen JH, Hu W. [Cloning, expression and bioinformatics analysis of cathepsin B of Echinococcus granulosus]. Zhongguo Xue Xi Chong Bing Fang Zhi Za Zhi 2014; 26:642-647. [PMID: 25856890] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
OBJECTIVE To clone and express cathepsin B gene of Echinococcus granulosus (EgCatB) and analyze EgCatB protein by using bioinformatics tools and online databases. METHODS The total RNA of E. granulosus was extracted and reversely transcribed into cDNA as the template sequence for PCR. The EgCatB gene was cloned by using the In-Fusion PCR cloning method and expressed by a wheat germ cell-free system, and then the recombinant protein was identified by Western blotting. The signal peptide, transmembrane helices and subcellular location of the EgCatB sequence were predicted by the online software SignalP 4.1, TMHMM sever v. 2.0 and TargetP 1.1 respectively. Subsequently, the homologue sequence and conserved sites were aligned by using BLASTP and GeneDoc software. Finally, the structures and the glycosylation modification site of the EgCatB encoding protein were analyzed and predicted in turn by ProtParam, SMART, Predictprotein, Swiss-model, NetOGlyc 4.0 and NetNGlyc 1.0 approaches. RESULTS The EgCatB gene was successfully amplified from cDNA of E. granulosus and expressed in the soluble fractions. The molecular weight of the expressed protein was estimated 35 kDa. The bioinformatics analysis revealed that EgCatB was a classical secreted protein containing a Pept_C1 domain. The homology analysis indicated that the amino acid sequence of EgCatB was highly conserved in the active enzyme sites. The protein structure prediction showed a catalytic active center was formed through Gln106, Cys112, His282 and Asn302. It was found that there were nine O-glycosylation sites in the EgCatB sequence, but no N-glycosylation sites. CONCLUSIONS The EgCatB gene is cloned and expressed successfully, and the recombinant protein is analyzed by bioinformatics approaches and structure predication. The study provides useful information for further functional study of the EgCatB protein.
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Obal G, Ramos AL, Silva V, Lima A, Batthyany C, Bessio MI, Ferreira F, Salinas G, Ferreira AM. Characterisation of the native lipid moiety of Echinococcus granulosus antigen B. PLoS Negl Trop Dis 2012; 6:e1642. [PMID: 22616019 PMCID: PMC3352830 DOI: 10.1371/journal.pntd.0001642] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2012] [Accepted: 03/29/2012] [Indexed: 12/21/2022] Open
Abstract
Antigen B (EgAgB) is the most abundant and immunogenic antigen produced by the larval stage (metacestode) of Echinococcus granulosus. It is a lipoprotein, the structure and function of which have not been completely elucidated. EgAgB apolipoprotein components have been well characterised; they share homology with a group of hydrophobic ligand binding proteins (HLBPs) present exclusively in cestode organisms, and consist of different isoforms of 8-kDa proteins encoded by a polymorphic multigene family comprising five subfamilies (EgAgB1 to EgAgB5). In vitro studies have shown that EgAgB apolipoproteins are capable of binding fatty acids. However, the identity of the native lipid components of EgAgB remains unknown. The present work was aimed at characterising the lipid ligands bound to EgAgB in vivo. EgAgB was purified to homogeneity from hydatid cyst fluid and its lipid fraction was extracted using chloroform∶methanol mixtures. This fraction constituted approximately 40-50% of EgAgB total mass. High-performance thin layer chromatography revealed that the native lipid moiety of EgAgB consists of a variety of neutral (mainly triacylglycerides, sterols and sterol esters) and polar (mainly phosphatidylcholine) lipids. Gas-liquid chromatography analysis showed that 16∶0, 18∶0 and 18∶1(n-9) are the most abundant fatty acids in EgAgB. Furthermore, size exclusion chromatography coupled to light scattering demonstrated that EgAgB comprises a population of particles heterogeneous in size, with an average molecular mass of 229 kDa. Our results provide the first direct evidence of the nature of the hydrophobic ligands bound to EgAgB in vivo and indicate that the structure and composition of EgAgB lipoprotein particles are more complex than previously thought, resembling high density plasma lipoproteins. Results are discussed considering what is known on lipid metabolism in cestodes, and taken into account the Echinococcus spp. genomic information regarding both lipid metabolism and the EgAgB gene family.
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Affiliation(s)
- Gonzalo Obal
- Cátedra de Inmunología, Facultad de Ciencias/Facultad de Química, Universidad de la República (UdelaR), Montevideo, Uruguay
- Unidad de Biofísica de Proteínas, Instituto Pasteur de Montevideo, Montevideo, Uruguay
| | - Ana Lía Ramos
- Cátedra de Inmunología, Facultad de Ciencias/Facultad de Química, Universidad de la República (UdelaR), Montevideo, Uruguay
| | - Valeria Silva
- Cátedra de Inmunología, Facultad de Ciencias/Facultad de Química, Universidad de la República (UdelaR), Montevideo, Uruguay
| | - Analía Lima
- Unidad de Bioquímica y Proteómica Analíticas, Instituto Pasteur de Montevideo, Montevideo, Uruguay
| | - Carlos Batthyany
- Unidad de Bioquímica y Proteómica Analíticas, Instituto Pasteur de Montevideo, Montevideo, Uruguay
| | - María Inés Bessio
- Laboratorio de Carbohidratos y Glicoconjugados, Departamento de Química Orgánica/Departamento de Desarrollo Biotecnológico, Facultad de Química/Facultad de Medicina, Universidad de la República (UdelaR), Montevideo, Uruguay
| | - Fernando Ferreira
- Laboratorio de Carbohidratos y Glicoconjugados, Departamento de Química Orgánica/Departamento de Desarrollo Biotecnológico, Facultad de Química/Facultad de Medicina, Universidad de la República (UdelaR), Montevideo, Uruguay
| | - Gustavo Salinas
- Cátedra de Inmunología, Facultad de Ciencias/Facultad de Química, Universidad de la República (UdelaR), Montevideo, Uruguay
| | - Ana María Ferreira
- Cátedra de Inmunología, Facultad de Ciencias/Facultad de Química, Universidad de la República (UdelaR), Montevideo, Uruguay
- * E-mail:
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10
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Monteiro KM, de Carvalho MO, Zaha A, Ferreira HB. Proteomic analysis of the Echinococcus granulosus metacestode during infection of its intermediate host. Proteomics 2010; 10:1985-99. [PMID: 20217864 DOI: 10.1002/pmic.200900506] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Cystic hydatid disease (CHD) is caused by infection with the Echinococcus granulosus metacestode and affects both humans and livestock. In this work, we performed a proteomic analysis of the E. granulosus metacestode during infection of its intermediate bovine host. Parasite proteins were identified in different metacestode components (94 from protoscolex, 25 from germinal layer and 20 from hydatid cyst fluid), along with host proteins (58) that permeate into the hydatid cyst, providing new insights into host-parasite interplay. E. granulosus and platyhelminth EST data allowed successful identification of proteins potentially involved in downregulation of host defenses, highlighting possible evasion mechanisms adopted by the parasite to establish infection. Several intracellular proteins were found in hydatid cyst fluid, revealing a set of newly identified proteins that were previously thought to be inaccessible for inducing or modulating the host immune response. Host proteins identified in association with the hydatid cyst suggest that the parasite may bind/adsorb host molecules with nutritional and/or immune evasion purposes, masking surface antigens or inhibiting important effector molecules of host immunity, such as complement components and calgranulin. Overall, our results provide valuable information on parasite survival strategies in the adverse host environment and on the molecular mechanisms underpinning CHD immunopathology.
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Affiliation(s)
- Karina M Monteiro
- Laboratório de Biologia Molecular de Cestódeos e Laboratório de Genômica Estrutural e Funcional, Centro de Biotecnologia, UFRGS, Porto Alegre, RS, Brazil
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11
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Casaravilla C, Díaz A. Studies on the structural mucins of the Echinococcus granulosus laminated layer. Mol Biochem Parasitol 2010; 174:132-6. [PMID: 20692297 DOI: 10.1016/j.molbiopara.2010.07.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2010] [Revised: 07/23/2010] [Accepted: 07/28/2010] [Indexed: 11/18/2022]
Abstract
The larvae of the cestodes belonging to the genus Echinococcus are outwardly protected by the laminated layer (LL), a crucial but poorly understood carbohydrate-rich acellular structure. Carbohydrate structural data strongly suggest that the main components of the LL are mucins. The most massive LL in the genus is featured by E. granulosus, agent of cystic hydatid disease. No appropriate methods existed to date for the solubilisation of the E. granulosus LL and the electrophoretic visualisation of its proposed structural mucins. We report that reduction of disulphides greatly aids LL disassembly, resulting in almost full solubilisation in combination with moderate sonication. The structural mucins can then be visualised by agarose electrophoresis and blotting with galactose-binding lectins, which also react strongly with the LL in tissue sections. A substantial portion of the material migrates as if positively charged; since the LL glycans are neutral, this may correspond to mucins with cationic peptide backbones.
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Affiliation(s)
- Cecilia Casaravilla
- Departamento de Biociencias, Facultad de Química and IQB, Universidad de la República, Instituto de Higiene, Montevideo CP, Uruguay
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12
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Taherkhani H, Zeyhle E, Rogan MT. Antibody responses in human cystic hydatid disease to the laminated layer of Echinococcus granulosus. Parasitol Res 2007; 101:647-52. [PMID: 17429692 DOI: 10.1007/s00436-007-0534-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2006] [Accepted: 03/14/2007] [Indexed: 11/26/2022]
Abstract
The laminated layer of hydatid cysts of Echinococcus granulosus represents a considerable amount of parasite material. Its antigenic role, however, is unclear. Extracts of laminated layer taken from sheep cysts were analysed in sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS/PAGE) and were found to contain bands at 55 and 25-29 kDa, which reacted with an anti-sheep IgG antibody probe, indicating that these were likely to be host-contaminating components within the layer. However, the same bands were also recognised by a significant proportion of human hydatid patients, particularly by IgG4 antibodies, and not by negative control individuals. These individuals did not recognise immunoglobulin heavy and light chains in a sheep serum extract in the same manner. It seems likely that there are either host or parasite antigenic components at similar molecular weights or that certain parasite antigens may share epitopes with sheep immunoglobulins. The antigens at 25-29 kDa were found to be glycoproteins by lectin blot analysis and may be important markers of disease status.
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Affiliation(s)
- H Taherkhani
- Medical Parasitology Department, Golestan University of Medical Sciences, Gorgan, Iran
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13
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Abstract
Many serological tests are widely used in the diagnosis of cystic echinococcosis (CE), caused by the larval stages of Echinococcus granulosus. The present study was carried for differentiation between hepatic and pulmonary cystic echinococcosis by Western Blotting (WB). A total of 121 sera from patients with hepatic CE (37), pulmonary CE (31) and controls (53; consisting of six healthy, seven Hymenolepis nana infection, 20 hepatic and 20 pulmonary diseases other than CE) were examined. In all of the CE patients, E. gronulosus infection was confirmed by surgical intervention. Sera were previously tested using IHA and ELISA to detect the E. gronulosus specific antibodies. Sera from hepatic cases of CE reacted with 16 polypeptides of 6-116 kDa and sera from pulmonary cases of CE reacted with 14 polypeptides of 4-130 kDa by Western Blotting. The WB test enabled the detection of antibodies in the hepatic CE samples for proteins of 24, 32 34, 44-46 and 52-54 kDa in molecular weight in 78.4%, 75.7%, 78.4% and 89.2% of the patients, respectively. In the pulmonary CE samples sera WB test enabled the detection of antibodies 24, 44-46, 100, 110, 116 and 120 124 kDa in molecular weight in 81.3%, 75.0%, 87.5%, 71.9%, 84.4% and 65.6% of the patients, respectively. We indicated that the antigenic components of high molecular weight can be good candidates for differentiation of hepatic CE from pulmonary CE.
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Affiliation(s)
- C Akisu
- Dokuz Eylul University, Medical Faculty, Department of Parasitology, Izmir, Turkey.
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14
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Kamel MM, Maher KM, Rabia I, Helmy AH, El-Adawi AI, Mousa MA, Mahgoub AM. A Con A- purified hydatid glycoprotein fraction effectively diagnoses human hydatidosis. J Egypt Soc Parasitol 2006; 36:945-58. [PMID: 17153705] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Diagnosis and quantification of Echinococcus granulosus infection in man and animal hosts are centralized to feasible control. This study included 93 serum samples, 25 sure positive hydatid cases confirmed surgically, 7 suspected cases diagnosed by indirect haemagglutination IHA and 41 cases other parasitic infections (15 S. mansoni, 8 Fasciola, 7 Ascaris, 5 H. nana & 6 Ancylostoma) diagnosed by microscopic examination and were negative by ELISA and/or IHA for anti-hydatid antibody. Twenty negative serum samples served as healthy controls. Six types of hydatid fluid antigens (crude, host-free & Con-A purified) of human and camel origin were subjected to electrophoretic separation (SDS-PAGE) and immunoblotting (EITB). The anti-hydatid IgG was detected in sera of the different groups for evaluation of sensitivity, specificity and diagnostic efficacy of each type of antigens. Detection of circulating hydatid antigen (CAg) was performed using anti rabbit hyperimmune sera raised against Con-A purified either human or camel hydatid antigen. SDS-PAGE revealed several bands ranging from 55-185 kDa with 10 kDa band shared by all antigens. The specific bands revealed by EITB for Con-A purified camel and human antigens were at 80, 110 & 55, 110 kDa respectively. ELISA highest sensitivity (96.9%) was by using host-free Con-A purified glycoprotein fraction of human hydatid antigen. Highest specificity (98.4%) was recorded upon use of either Con-A purified camel or human antigen with 94.5% & 97.7% diagnostic efficacy respectively. Detection of circulating antigen by polyclonal antibodies against Con-A purified human hydatid antigen revealed 91.8% specificity.
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Affiliation(s)
- Manal M Kamel
- Department of Immunology, Theodor Bilharz Research Institute, Imbaba P.O. Box 30, Giza, Egypt
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15
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Casaravilla C, Brearley C, Soulé S, Fontana C, Veiga N, Bessio MI, Ferreira F, Kremer C, Díaz A. Characterization of myo-inositol hexakisphosphate deposits from larval Echinococcus granulosus. FEBS J 2006; 273:3192-203. [PMID: 16792701 DOI: 10.1111/j.1742-4658.2006.05328.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The abundant metabolite myo-inositol hexakisphosphate (InsP6) can form vesicular deposits with cations, a widespread phenomenon in plants also found in the cestode parasite, Echinococcus granulosus. In this organism, the deposits are exocytosed, accumulating in a host-exposed sheath of extracellular matrix termed the laminated layer. The formation and mobilization of InsP6 deposits, which involve precipitation and solubilization reactions, respectively, cannot yet be rationalized in quantitative chemical terms, as the solids involved have not been formally described. We report such a description for the InsP6 deposits from E. granulosus, purified as the solid residue left by mild alkaline digestion of the principal mucin component of the laminated layer. The deposits are largely composed of the compound Ca5H2L.16H2O (L representing fully deprotonated InsP6), and additionally contain Mg2+ (6-9% molar ratio with respect to Ca2+), but not K+. Calculations employing recently available chemical constants show that the precipitation of Ca5H2L.16H2O is predicted by thermodynamics in secretory vesicle-like conditions. The deposits appear to be similar to microcrystalline solids when analysed under the electron microscope; we estimate that each crystal comprises around 200 InsP6 molecules. We calculate that the deposits increase, by three orders of magnitude, the surface area available for adsorption of host proteins, a salient ability of the laminated layer. The major inositol phosphate in the deposits, other than InsP6, is myo-inositol (1,2,4,5,6) pentakisphosphate, or its enantiomer, inositol (2,3,4,5,6) pentakisphosphate. The compound appears to be a subproduct of the intracellular pathways leading to the synthesis and vesicular accumulation of InsP6, rather than arising from extracellular hydrolysis of InsP6.
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Affiliation(s)
- Cecilia Casaravilla
- Cátedra de Inmunología, Facultad de Química/Ciencias, Universidad de la República, Montevideo, Uruguay
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16
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Grimm ED, Portugal RV, de Oliveira Neto M, Martins NH, Polikarpov I, Zaha A, Ferreira HB. Structural analysis of an Echinococcus granulosus actin-fragmenting protein by small-angle x-ray scattering studies and molecular modeling. Biophys J 2006; 90:3216-23. [PMID: 16473915 PMCID: PMC1432106 DOI: 10.1529/biophysj.105.067801] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The Echinococcus granulosus actin filament-fragmenting protein (EgAFFP) is a three domain member of the gelsolin family of proteins, which is antigenic to human hosts. These proteins, formed by three or six conserved domains, are involved in the dynamic rearrangements of the cytoskeleton, being responsible for severing and capping actin filaments and promoting nucleation of actin monomers. Various structures of six domain gelsolin-related proteins have been investigated, but little information on the structure of three domain members is available. In this work, the solution structure of the three domain EgAFFP has been investigated through small-angle x-ray scattering (SAXS) studies. EgAFFP exhibits an elongated molecular shape. The radius of gyration and the maximum dimension obtained by SAXS were, respectively, 2.52 +/- 0.01 nm and 8.00 +/- 1.00 nm, both in the absence and presence of Ca2+. Two different molecular homology models were built for EgAFFP, but only one was validated through SAXS studies. The predicted structure for EgAFFP consists of three repeats of a central beta-sheet sandwiched between one short and one long alpha-helix. Possible implications of the structure of EgAFFP upon actin binding are discussed.
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Affiliation(s)
- Eliana D Grimm
- Laboratório de Biologia Molecular de Cestódeos, Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre RS, Brazil
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Naidich A, McManus DP, Canova SG, Gutierrez AM, Zhang W, Guarnera EA, Rosenzvit MC. Patent and pre-patent detection of Echinococcus granulosus genotypes in the definitive host. Mol Cell Probes 2006; 20:5-10. [PMID: 16226869 DOI: 10.1016/j.mcp.2005.08.001] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2005] [Accepted: 08/22/2005] [Indexed: 11/18/2022]
Abstract
The detection of Echinococcus granulosus in dogs is important for epidemiological surveillance and evaluation of cystic hydatic disease control programs. We report the efficacy of two PCR-based methods to detect patent and pre-patent infection in dogs experimentally infected with E. granulosus. The detection is based on amplification of a fragment of a mitochondrial gene (Mit-PCR) and a DNA repetitive element (Rep-PCR) of E. granulosus. We tested the ability of both methods to detect several genotypes of the parasite. Both PCR methods could detect E. granulosus in pre-patent and patent periods, even when microscopical observation of eggs resulted negative in fecal samples. The Mit-PCR produced the same amplification pattern for all the parasite genotypes tested while the amplification patterns with the Rep-PCR differed among groups of strains. Fecal samples collected from dogs of an endemic area were diagnosed with more sensitivity than arecoline hydrobromide purgation. These molecular methods could be applied in the confirmation of coproantigen-positive fecal samples and to verify the success of control programs.
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Affiliation(s)
- Ariel Naidich
- Departamentode Parasitología, Instituto Nacional de Enfermedades Infecciosas, ANLIS Dr Carlos G. Malbrán, Av. Velez Sarsfield 563, 1281 Ciudad de Buenos Aires, Argentina.
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18
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Rosenzvit MC, Zhang W, Motazedian H, Smyth D, Pearson M, Loukas A, Jones MK, McManus DP. Identification of membrane-bound and secreted proteins from Echinococcus granulosus by signal sequence trap. Int J Parasitol 2006; 36:123-30. [PMID: 16229848 DOI: 10.1016/j.ijpara.2005.09.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2005] [Revised: 08/14/2005] [Accepted: 09/07/2005] [Indexed: 10/25/2022]
Abstract
The signal sequence trap technique was applied to identify genes coding for secreted and membrane bound proteins from Echinococcus granulosus, the etiologic agent of cystic hydatid disease. An E. granulosus protoscolex cDNA library was constructed in the AP-PST vector such that randomly primed cDNAs were fused with a placental alkaline phosphatase reporter gene lacking its endogenous signal peptide. E. granulosus cDNAs encoding a functional signal peptide were selected by their ability to rescue secretion of alkaline phosphatase by COS-7 cells that had been transfected with the cDNA library. Eighteen positive clones were identified and sequenced. Their deduced amino acid sequences showed significant similarity with amino acid transporters, Krebs cycle intermediates transporters, presenilins and vacuolar protein sorter proteins. Other cDNAs encoded secreted proteins without homologues. Three sequences were transcribed antisense to E. granulosus expressed sequence tags. All the mRNAs were expressed in protoscoleces and adult worms, but some of them were not found in oncospheres. The putative E. granulosus secreted and membrane bound proteins identified are likely to play important roles in the metabolism, development and survival in the host and represent potential targets for diagnosis, drugs and vaccines against E. granulosus.
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Affiliation(s)
- Mara C Rosenzvit
- Queensland Institute of Medical Research, 300 Herston Road, Herston, Brisbane, Qld 4029, Australia.
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Irigoín F, Casaravilla C, Iborra F, Sim RB, Ferreira F, Díaz A. Unique precipitation and exocytosis of a calcium salt of myo-inositol hexakisphosphate in larval Echinococcus granulosus. J Cell Biochem 2005; 93:1272-81. [PMID: 15486919 DOI: 10.1002/jcb.20262] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The ubiquitous intracellular molecule myo-inositol hexakisphosphate (IP6) is present extracellularly in the hydatid cyst wall (HCW) of the parasitic cestode Echinococcus granulosus. This study shows that extracellular IP6 is present as its solid calcium salt, in the form of deposits that are observed, at the ultrastructural level, as naturally electron dense granules some tens of nanometers in diameter. The presence of a calcium salt of IP6 in these structures was determined by two different electron microscopy techniques: (i) the analysis of the spatial distribution of phosphorus and calcium in the outer, acellular layer of the HCW (the laminated layer, LL) through electron energy loss spectroscopy, and (ii) the observation, by transmission electron microscopy, of HCW that were selectively depleted of IP6 by treatment with EGTA or phytase, an enzyme that catalyses the dephosphorylation of IP6. The deposits of the IP6-Ca(II) salt are also observed inside membrane vesicles in cells of the germinal layer (the inner, cellular layer of the HCW), indicating that IP6 precipitates with calcium within a cellular vesicular compartment and is then secreted to the LL. Thus, much as in plants (that produce vesicular IP6 deposits), the existence of transporters for IP6 or its precursors in internal membranes is needed to explain the compound's cellular localisation in E. granulosus.
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Affiliation(s)
- Florencia Irigoín
- Cátedra de Inmunología, Facultad de Química/Ciencias, Universidad de la República, Uruguay
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