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Wang H, Marucci G, Munke A, Hassan MM, Lalle M, Okamoto K. High-resolution comparative atomic structures of two Giardiavirus prototypes infecting G. duodenalis parasite. PLoS Pathog 2024; 20:e1012140. [PMID: 38598600 PMCID: PMC11081498 DOI: 10.1371/journal.ppat.1012140] [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] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Revised: 05/09/2024] [Accepted: 03/21/2024] [Indexed: 04/12/2024] Open
Abstract
The Giardia lamblia virus (GLV) is a non-enveloped icosahedral dsRNA and endosymbiont virus that infects the zoonotic protozoan parasite Giardia duodenalis (syn. G. lamblia, G. intestinalis), which is a pathogen of mammals, including humans. Elucidating the transmission mechanism of GLV is crucial for gaining an in-depth understanding of the virulence of the virus in G. duodenalis. GLV belongs to the family Totiviridae, which infects yeast and protozoa intracellularly; however, it also transmits extracellularly, similar to the phylogenetically, distantly related toti-like viruses that infect multicellular hosts. The GLV capsid structure is extensively involved in the longstanding discussion concerning extracellular transmission in Totiviridae and toti-like viruses. Hence, this study constructed the first high-resolution comparative atomic models of two GLV strains, namely GLV-HP and GLV-CAT, which showed different intracellular localization and virulence phenotypes, using cryogenic electron microscopy single-particle analysis. The atomic models of the GLV capsids presented swapped C-terminal extensions, extra surface loops, and a lack of cap-snatching pockets, similar to those of toti-like viruses. However, their open pores and absence of the extra crown protein resemble those of other yeast and protozoan Totiviridae viruses, demonstrating the essential structures for extracellular cell-to-cell transmission. The structural comparison between GLV-HP and GLV-CAT indicates the first evidence of critical structural motifs for the transmission and virulence of GLV in G. duodenalis.
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Affiliation(s)
- Han Wang
- The Laboratory of Molecular Biophysics, Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden
| | - Gianluca Marucci
- Unit of Foodborne and Neglected Parasitic Diseases, Department of Infectious Diseases, Istituto Superiore di Sanità (ISS), Rome, Italy
| | - Anna Munke
- The Laboratory of Molecular Biophysics, Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden
- Center for Free-Electron Laser Science CFEL, Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany
| | - Mohammad Maruf Hassan
- The Laboratory of Molecular Biophysics, Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden
| | - Marco Lalle
- Unit of Foodborne and Neglected Parasitic Diseases, Department of Infectious Diseases, Istituto Superiore di Sanità (ISS), Rome, Italy
| | - Kenta Okamoto
- The Laboratory of Molecular Biophysics, Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden
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Verdan R, Patricio B, Weismuller G, Miranda K, de Souza W, Benchimol M, Gadelha AP. Characterization of a new extra-axonemal structure in the Giardia intestinalis flagella. J Struct Biol 2024; 216:108064. [PMID: 38280689 DOI: 10.1016/j.jsb.2024.108064] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Revised: 01/05/2024] [Accepted: 01/18/2024] [Indexed: 01/29/2024]
Abstract
The inner structure of the flagella of Giardia intestinalis is similar to that of other organisms, consisting of nine pairs of outer microtubules and a central pair containing radial spokes. Although the 9+2 axonemal structure is conserved, it is not clear whether subregions, including the transition zone, are present in the flagella of this parasite. Giardia axonemes originate from basal bodies and have a lengthy cytosolic portion before becoming active flagella. The region of the emergence of the flagellum is not accompanied by any membrane specialization, as seen in other protozoa. Although Giardia is an intriguing model of study, few works focused on the ultrastructural analysis of the flagella of this parasite. Here, we analyzed the externalization region of the G. intestinalis flagella using ultra-high resolution scanning microscopy (with electrons and ions), atomic force microscopy in liquid medium, freeze fracture, and electron tomography. Our data show that this region possesses a distinctive morphological feature - it extends outward and takes on a ring-like shape. When the plasma membrane is removed, a structure surrounding the axoneme becomes visible in this region. This new extra-axonemal structure is observed in all pairs of flagella of trophozoites and remains attached to the axoneme even when the interconnections between the axonemal microtubules are disrupted. High-resolution scanning electron microscopy provided insights into the arrangement of this structure, contributing to the characterization of the externalization region of the flagella of this parasite.
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Affiliation(s)
- Raphael Verdan
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil
| | - Beatriz Patricio
- Instituto Biomédico, Universidade Federal do Estado Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil
| | - Gilberto Weismuller
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil
| | - Kildare Miranda
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil; Centro Nacional de Biologia Estrutural e Bioimagem e Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Bioimagens, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil; Centro Multiusuário para Análise de Fenômenos Biomédicos, Universidade do Estado do Amazonas, Manaus, Brazil
| | - Wanderley de Souza
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil; Centro Nacional de Biologia Estrutural e Bioimagem e Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Bioimagens, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil; Centro Multiusuário para Análise de Fenômenos Biomédicos, Universidade do Estado do Amazonas, Manaus, Brazil
| | - Marlene Benchimol
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil; Centro Nacional de Biologia Estrutural e Bioimagem e Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Bioimagens, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil; Universidade do Grande Rio (UNIGRANRIO), Rio de Janeiro, RJ, Brazil
| | - Ana Paula Gadelha
- Universidade do Grande Rio (UNIGRANRIO), Rio de Janeiro, RJ, Brazil; Diretoria de Metrologia Científica e Industrial, Instituto Nacional de Metrologia, Qualidade e Tecnologia (INMETRO), Rio de Janeiro, Rio de Janeiro, Brazil.
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Benchimol M. Giardia intestinalis can interact, change its shape and internalize large particles and microorganisms. Parasitology 2021; 148:500-510. [PMID: 33280628 PMCID: PMC11010223 DOI: 10.1017/s0031182020002292] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [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: 08/02/2020] [Revised: 10/05/2020] [Accepted: 11/25/2020] [Indexed: 11/06/2022]
Abstract
Giardia intestinalis is a parasitic protozoan that inhabits its vertebrate hosts' upper small intestine and is the most common cause of waterborne diarrhoea worldwide. Giardia trophozoites present few organelles, and among them, they possess peripheral vesicles (PVs), which are considered an endosomal-lysosomal system. All experimental procedures carried out until now indicate that Giardia ingests macromolecules by fluid-phase and receptor-mediated endocytic pathways. Still, there is no description concerning the interaction and ingestion of large materials. Here, we tested Giardia's capacity to interact with large particles; once, in vivo, it inhabits an environment with a microbiota. We tested protozoan interaction with yeasts, bacteria, latex beads, ferritin and albumin, in different times of interaction and used several microscopy techniques (light microscopy, scanning electron microscopy and transmission electron microscopy) to follow their fate. Giardia interacted with all of the materials we tested. Projections of the plasma membrane similar to pseudopods were seen. As albumin, small markers were found in the PVs while the larger materials were not seen there. Large vacuoles containing large latex beads were detected intracellularly. Thus, we observed that: (1) Giardia interacts with large materials; (2) Giardia can display an amoeboid shape and exhibit membrane projections when in contact with microorganisms and large inorganic materials; (3) the region of the exit of the ventral flagella is very active when in contact with large materials, although all cell surface also present activity in the interactions; (4) intracellular vacuoles, which are not the PVs, present ingested large beads.
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Affiliation(s)
- Marlene Benchimol
- UNIGRANRIO-Universidade do Grande Rio-Duque de Caxias-Rio de Janeiro, Rio de Janeiro, Brazil
- UFRJ-Universidade Federal do Rio de Janeiro-Instituto de Biofísica Carlos Chagas Filho-Laboratório de Ultraestrutura Celular Hertha Meyer, and Instituto Nacional de Ciência e Tecnologia-INBEB, Centro Nacional de Biologia Estrutural e Bioimagens-CENABIO, Rio de Janeiro, Brazil
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Affiliation(s)
- Lenka Cernikova
- Laboratory of Molecular Parasitology, Institute of Parasitology, University of Zurich (ZH), Zurich, Switzerland
| | - Carmen Faso
- Laboratory of Molecular Parasitology, Institute of Parasitology, University of Zurich (ZH), Zurich, Switzerland
| | - Adrian B. Hehl
- Laboratory of Molecular Parasitology, Institute of Parasitology, University of Zurich (ZH), Zurich, Switzerland
- * E-mail:
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Beiromvand M, Mirrezaie E, Mirzavand S. Foodborne Giardiasis: Is There Any Relationship Between food Handlers and Transmission of Giardia duodenalis? Infect Disord Drug Targets 2017; 17:72-76. [PMID: 28079004 DOI: 10.2174/1871526517666170111105040] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [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: 11/23/2016] [Revised: 12/29/2016] [Accepted: 01/04/2017] [Indexed: 06/06/2023]
Abstract
BACKGROUND The foodborne diseases are amongst the main causes of morbidity and mortality in the human communities. Giardia duodenalis, the causative agent of giardiasis, is one of the foodborne parasites, which has public health importance. The aim of the current study was to assess the prevalence of G. duodenalis among food handlers in Andimeshk County, southwest of Iran. MATERIALS AND METHODS This cross-sectional study was undertaken among 480 food handlers in 2015. The collected stool specimens were investigated using direct saline smear, Lugol's iodine- staining, and sucrose flotation methods. RESULTS The overall prevalence of G. duodenalis in the examined participants was 12 (2.5%). The higher prevalence 75% (9/12) was found among participants with medium and low levels of education and 25% (3/12) belonged to those with high level of education. Direct microscopic examinations revealed two (0.4%) positive cases infected with Hymenolepis nana, with one of them showing mixed infection with G. duodenalis. CONCLUSION Based on the obtained results, infected food handlers could be a potential source of intestinal parasitic infections, and transmission can occur through contaminated food. Therefore, we suggest that food handlers training programs should be implemented to increase the awareness of food handlers and reduce the transmission of intestinal parasites.
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Affiliation(s)
- Molouk Beiromvand
- Department of Parasitology, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran, P.O. Box 61357-15794 Ahvaz, Iran
| | - Ehsanallah Mirrezaie
- Department of Parasitology, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| | - Somayeh Mirzavand
- Department of Parasitology, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
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Rout S, Zumthor JP, Schraner EM, Faso C, Hehl AB. An Interactome-Centered Protein Discovery Approach Reveals Novel Components Involved in Mitosome Function and Homeostasis in Giardia lamblia. PLoS Pathog 2016; 12:e1006036. [PMID: 27926928 PMCID: PMC5142787 DOI: 10.1371/journal.ppat.1006036] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [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: 07/27/2016] [Accepted: 11/01/2016] [Indexed: 12/23/2022] Open
Abstract
Protozoan parasites of the genus Giardia are highly prevalent globally, and infect a wide range of vertebrate hosts including humans, with proliferation and pathology restricted to the small intestine. This narrow ecological specialization entailed extensive structural and functional adaptations during host-parasite co-evolution. An example is the streamlined mitosomal proteome with iron-sulphur protein maturation as the only biochemical pathway clearly associated with this organelle. Here, we applied techniques in microscopy and protein biochemistry to investigate the mitosomal membrane proteome in association to mitosome homeostasis. Live cell imaging revealed a highly immobilized array of 30–40 physically distinct mitosome organelles in trophozoites. We provide direct evidence for the single giardial dynamin-related protein as a contributor to mitosomal morphogenesis and homeostasis. To overcome inherent limitations that have hitherto severely hampered the characterization of these unique organelles we applied a novel interaction-based proteome discovery strategy using forward and reverse protein co-immunoprecipitation. This allowed generation of organelle proteome data strictly in a protein-protein interaction context. We built an initial Tom40-centered outer membrane interactome by co-immunoprecipitation experiments, identifying small GTPases, factors with dual mitosome and endoplasmic reticulum (ER) distribution, as well as novel matrix proteins. Through iterative expansion of this protein-protein interaction network, we were able to i) significantly extend this interaction-based mitosomal proteome to include other membrane-associated proteins with possible roles in mitosome morphogenesis and connection to other subcellular compartments, and ii) identify novel matrix proteins which may shed light on mitosome-associated metabolic functions other than Fe-S cluster biogenesis. Functional analysis also revealed conceptual conservation of protein translocation despite the massive divergence and reduction of protein import machinery in Giardia mitosomes. Organelles with endosymbiotic origin are present in virtually all extant eukaryotes and have undergone considerable remodeling during > 1 billion years of evolution. Highly diverged organelles such as mitosomes or plastids in some parasitic protozoa are the product of extensive secondary reduction. They are sufficiently unique to generate interest as targets for pharmacological intervention, in addition to providing a rich ground for evolutionary cell biologists. The so-called mitochondria-related organelles (MROs) comprise mitosomes and hydrogenosomes, with the former having lost any role in energy metabolism along with the organelle genome. The mitosomes of the intestinal pathogen Giardia lamblia are the most highly reduced MROs known and have proven difficult to investigate because of their extreme divergence and their unique biophysical properties. Here, we implemented a novel strategy aimed at systematic analysis of the organelle proteome by iterative expansion of a protein-protein interaction network. We combined serial forward and reverse co-immunoprecipitations with mass spectrometry analysis, data mining, and validation by subcellular localization and/or functional analysis to generate an interactome network centered on a giardial Tom40 homolog. This iterative ab initio proteome reconstruction provided protein-protein interaction data in addition to identifying novel organelle proteins and functions. Building on this data we generated information on organelle replication, mitosome morphogenesis and organelle dynamics in living cells.
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Affiliation(s)
- Samuel Rout
- Institute of Parasitology, University of Zurich (ZH), Zurich, Switzerland
| | - Jon Paulin Zumthor
- Institute of Parasitology, University of Zurich (ZH), Zurich, Switzerland
| | | | - Carmen Faso
- Institute of Parasitology, University of Zurich (ZH), Zurich, Switzerland
- * E-mail: (ABH); (CF)
| | - Adrian B. Hehl
- Institute of Parasitology, University of Zurich (ZH), Zurich, Switzerland
- * E-mail: (ABH); (CF)
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7
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Zumthor JP, Cernikova L, Rout S, Kaech A, Faso C, Hehl AB. Static Clathrin Assemblies at the Peripheral Vacuole-Plasma Membrane Interface of the Parasitic Protozoan Giardia lamblia. PLoS Pathog 2016; 12:e1005756. [PMID: 27438602 PMCID: PMC4954726 DOI: 10.1371/journal.ppat.1005756] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [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: 02/26/2016] [Accepted: 06/18/2016] [Indexed: 11/19/2022] Open
Abstract
Giardia lamblia is a parasitic protozoan that infects a wide range of vertebrate hosts including humans. Trophozoites are non-invasive but associate tightly with the enterocyte surface of the small intestine. This narrow ecological specialization entailed extensive morphological and functional adaptations during host-parasite co-evolution, including a distinctly polarized array of endocytic organelles termed peripheral vacuoles (PVs), which are confined to the dorsal cortical region exposed to the gut lumen and are in close proximity to the plasma membrane (PM). Here, we investigated the molecular consequences of these adaptations on the Giardia endocytic machinery and membrane coat complexes. Despite the absence of canonical clathrin coated vesicles in electron microscopy, Giardia possesses conserved PV-associated clathrin heavy chain (GlCHC), dynamin-related protein (GlDRP), and assembly polypeptide complex 2 (AP2) subunits, suggesting a novel function for GlCHC and its adaptors. We found that, in contrast to GFP-tagged AP2 subunits and DRP, CHC::GFP reporters have no detectable turnover in living cells, indicating fundamental differences in recruitment to the membrane and disassembly compared to previously characterized clathrin coats. Histochemical localization in electron tomography showed that these long-lived GlCHC assemblies localized at distinctive approximations between the plasma and PV membrane. A detailed protein interactome of GlCHC revealed all of the conserved factors in addition to novel or highly diverged proteins, including a putative clathrin light chain and lipid-binding proteins. Taken together, our data provide strong evidence for giardial CHC as a component of highly stable assemblies at PV-PM junctions that likely have a central role in organizing continuities between the PM and PV membranes for controlled sampling of the fluid environment. This suggests a novel function for CHC in Giardia and the extent of molecular remodeling of endocytosis in this species. In canonical clathrin mediated endocytosis (CME) models, the concerted action of ca. 50 proteins mediates the uptake of extracellular components. The key player in this process is clathrin which coats transport intermediates called clathrin coated vesicles (CCV). The intestinal parasite Giardia lamblia has undergone extensive remodeling during colonization of the mammalian duodenum. Here, we report on unique features of this parasite’s endocytic system, consisting of fixed peripheral vacuoles (PV) in close proximity to the exposed plasma membrane (PM), with no discernible CCVs. Using state-of-the-art imaging strategies, we show that the surface of Giardia trophozoites is pock-marked with PM invaginations reaching to the underlying PV membrane. Co-immunoprecipitation and analysis of protein dynamics reveal that, in line with the absence of CCVs, giardial clathrin assemblies have no dynamic behavior. CHC still remains associated to AP2 and dynamin, both conserved dynamic CME components, and to a newly identified putative clathrin light chain. The emerging model calls for giardial clathrin organized into static cores surrounded by dynamic interaction partners, and most likely involved in the regulation of fusion between the PM and the PVs in a “kiss-and-flush”-like mechanism. This suggests that Giardia harbors a conceptually novel function for clathrin in endocytosis, which might be a consequence of host-parasite co-evolution.
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Affiliation(s)
| | - Lenka Cernikova
- Institute of Parasitology, University of Zurich, Zurich, Switzerland
| | - Samuel Rout
- Institute of Parasitology, University of Zurich, Zurich, Switzerland
| | - Andres Kaech
- Center for Microscopy and Image Analysis, University of Zurich, Zurich, Switzerland
| | - Carmen Faso
- Institute of Parasitology, University of Zurich, Zurich, Switzerland
- * E-mail: (CF); (ABH)
| | - Adrian B. Hehl
- Institute of Parasitology, University of Zurich, Zurich, Switzerland
- * E-mail: (CF); (ABH)
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Erlandsen SL, Jarroll E, Wallis P, van Keulen H. Development of Species-specific rDNA Probes for Giardia by Multiple Fluorescent In Situ Hybridization Combined with Immunocytochemical Identification of Cyst Wall Antigens. J Histochem Cytochem 2016; 53:917-27. [PMID: 15879572 DOI: 10.1369/jhc.5c6656.2005] [Citation(s) in RCA: 7] [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] [Indexed: 11/22/2022] Open
Abstract
In this study, we describe the development of fluorescent oligonucleotide probes to variable regions in the small subunit of 16S rRNA in three distinct Giardia species. Sense and antisense probes (17–22 mer) to variable regions 1, 3, and 8 were labeled with digoxygenin or selected fluorochomes (FluorX, Cy3, or Cy5). Optimal results were obtained with fluorochome-labeled oligonucleotides for detection of rRNA in Giardia cysts. Specificity of fluorescent in situ hybridization (FISH) was shown using RNase digestion and high stringency to diminish the hybridization signal, and oligonucleotide probes for rRNA in Giardia lamblia, Giardia muris, and Giardia ardeae were shown to specifically stain rRNA only within cysts or trophozoites of those species. The fluorescent oligonucleotide specific for rRNA in human isolates of Giardia was positive for ten different strains. A method for simultaneous FISH detection of cysts using fluorescent antibody (genotype marker) and two oligonucleotide probes (species marker) permitted visualization of G. lamblia and G. muris cysts in the same preparation. Testing of an environmental water sample revealed the presence of FISH-positive G. lamblia cysts with a specific rDNA probe for rRNA, while negative cysts were presumed to be of animal or bird origin.
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Affiliation(s)
- Stanley L Erlandsen
- Department of Genetics, Cell Biology, and Development, 6-160 Jackson Hall, University of Minnesota Medical School, Minneapolis, MN 55455, USA.
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Nyindodo-Ogari L, Schwartzbach SD, Skalli O, Estraño CE. Localizing Proteins in Fixed Giardia lamblia and Live Cultured Mammalian Cells by Confocal Fluorescence Microscopy. Methods Mol Biol 2016; 1474:93-111. [PMID: 27515076 DOI: 10.1007/978-1-4939-6352-2_6] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Confocal fluorescence microscopy and electron microscopy (EM) are complementary methods for studying the intracellular localization of proteins. Confocal fluorescence microscopy provides a rapid and technically simple method to identify the organelle in which a protein localizes but only EM can identify the suborganellular compartment in which that protein is present. Confocal fluorescence microscopy, however, can provide information not obtainable by EM but required to understand the dynamics and interactions of specific proteins. In addition, confocal fluorescence microscopy of cells transfected with a construct encoding a protein of interest fused to a fluorescent protein tag allows live cell studies of the subcellular localization of that protein and the monitoring in real time of its trafficking. Immunostaining methods for confocal fluorescence microscopy are also faster and less involved than those for EM allowing rapid optimization of the antibody dilution needed and a determination of whether protein antigenicity is maintained under fixation conditions used for EM immunogold labeling. This chapter details a method to determine by confocal fluorescence microscopy the intracellular localization of a protein by transfecting the organism of interest, in this case Giardia lamblia, with the cDNA encoding the protein of interest and then processing these organisms for double label immunofluorescence staining after chemical fixation. Also presented is a method to identify the organelle targeting information in the presequence of a precursor protein, in this case the presequence of the precursor to the Euglena light harvesting chlorophyll a/b binding protein of photosystem II precursor (pLHCPII), using live cell imaging of mammalian COS7 cells transiently transfected with a plasmid encoding a pLHCPII presequence fluorescent protein fusion and stained with organelle-specific fluorescent dyes.
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Affiliation(s)
- Lilian Nyindodo-Ogari
- Baptist College of Health Sciences, 1003 Monroe Avenue, Memphis, TN, 38104, USA
- Department of Biological Sciences, The University of Memphis, Memphis, TN, 38152, USA
| | - Steven D Schwartzbach
- Department of Biological Sciences, The University of Memphis, Life Sciences Bldg., Memphis, TN, 38152, USA
| | - Omar Skalli
- Department of Biological Sciences, The University of Memphis, Life Sciences Bldg., Memphis, TN, 38152, USA
| | - Carlos E Estraño
- Department of Biological Sciences, The University of Memphis, Life Sciences Bldg. Room 409B, Memphis, TN, 38152, USA.
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Ganz KR, Clime L, Farber JM, Corneau N, Veres T, Dixon BR. Enhancing the Detection of Giardia duodenalis Cysts in Foods by Inertial Microfluidic Separation. Appl Environ Microbiol 2015; 81:3925-33. [PMID: 25841016 PMCID: PMC4524145 DOI: 10.1128/aem.03868-14] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2014] [Accepted: 03/22/2015] [Indexed: 11/20/2022] Open
Abstract
The sensitivity and specificity of current Giardia cyst detection methods for foods are largely determined by the effectiveness of the elution, separation, and concentration methods used. The aim of these methods is to produce a final suspension with an adequate concentration of Giardia cysts for detection and a low concentration of interfering food debris. In the present study, a microfluidic device, which makes use of inertial separation, was designed and fabricated for the separation of Giardia cysts. A cyclical pumping platform and protocol was developed to concentrate 10-ml suspensions down to less than 1 ml. Tests involving Giardia duodenalis cysts and 1.90-μm microbeads in pure suspensions demonstrated the specificity of the microfluidic chip for cysts over smaller nonspecific particles. As the suspension cycled through the chip, a large number of beads were removed (70%) and the majority of the cysts were concentrated (82%). Subsequently, the microfluidic inertial separation chip was integrated into a method for the detection of G. duodenalis cysts from lettuce samples. The method greatly reduced the concentration of background debris in the final suspensions (10-fold reduction) in comparison to that obtained by a conventional method. The method also recovered an average of 68.4% of cysts from 25-g lettuce samples and had a limit of detection (LOD) of 38 cysts. While the recovery of cysts by inertial separation was slightly lower, and the LOD slightly higher, than with the conventional method, the sample analysis time was greatly reduced, as there were far fewer background food particles interfering with the detection of cysts by immunofluorescence microscopy.
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Affiliation(s)
- Kyle R Ganz
- Bureau of Microbial Hazards, Food Directorate, Health Products and Food Branch, Health Canada, Ottawa, Ontario, Canada
| | - Liviu Clime
- Life Sciences Division, National Research Council Canada, Boucherville, Quebec, Canada
| | - Jeffrey M Farber
- Bureau of Microbial Hazards, Food Directorate, Health Products and Food Branch, Health Canada, Ottawa, Ontario, Canada
| | - Nathalie Corneau
- Bureau of Microbial Hazards, Food Directorate, Health Products and Food Branch, Health Canada, Ottawa, Ontario, Canada
| | - Teodor Veres
- Life Sciences Division, National Research Council Canada, Boucherville, Quebec, Canada
| | - Brent R Dixon
- Bureau of Microbial Hazards, Food Directorate, Health Products and Food Branch, Health Canada, Ottawa, Ontario, Canada
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11
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Li WC, Gu YF, Liu C, Wu N, Luo WW, Gong PT, Li H, Li JH, Zhang XC. [In vitro effect of osthole on ultrastructure of Giardia lamblia]. Zhongguo Ji Sheng Chong Xue Yu Ji Sheng Chong Bing Za Zhi 2014; 32:242-244. [PMID: 25223065] [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: 06/03/2023]
Abstract
Giardia lamblia trophozoites were cultivated axenically in TYI-S-33 modified medium containing 1.345 mg/ml of osthole (24 h IC50). The parasites were observed by scanning and transmission electron microscopes after treated with osthole for 24 h. The surface of the trophozoites treated with osthole was rough. The surface of ventral sucker and median body had obvious lesions, the cell membrane was damaged and the content spilled out. There were a lot of vacuoles in the cytoplasm. And the nuclear was severely deformed with a serrated edge and marginated nuclear chromatin. The microtubules of sucker had partially disintegrated.
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Wampfler PB, Tosevski V, Nanni P, Spycher C, Hehl AB. Proteomics of secretory and endocytic organelles in Giardia lamblia. PLoS One 2014; 9:e94089. [PMID: 24732305 PMCID: PMC3986054 DOI: 10.1371/journal.pone.0094089] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Accepted: 03/10/2014] [Indexed: 11/20/2022] Open
Abstract
Giardia lamblia is a flagellated protozoan enteroparasite transmitted as an environmentally resistant cyst. Trophozoites attach to the small intestine of vertebrate hosts and proliferate by binary fission. They access nutrients directly via uptake of bulk fluid phase material into specialized endocytic organelles termed peripheral vesicles (PVs), mainly on the exposed dorsal side. When trophozoites reach the G2/M restriction point in the cell cycle they can begin another round of cell division or encyst if they encounter specific environmental cues. They induce neogenesis of Golgi-like organelles, encystation-specific vesicles (ESVs), for regulated secretion of cyst wall material. PVs and ESVs are highly simplified and thus evolutionary diverged endocytic and exocytic organelle systems with key roles in proliferation and transmission to a new host, respectively. Both organelle systems physically and functionally intersect at the endoplasmic reticulum (ER) which has catabolic as well as anabolic functions. However, the unusually high degree of sequence divergence in Giardia rapidly exhausts phylogenomic strategies to identify and characterize the molecular underpinnings of these streamlined organelles. To define the first proteome of ESVs and PVs we used a novel strategy combining flow cytometry-based organelle sorting with in silico filtration of mass spectrometry data. From the limited size datasets we retrieved many hypothetical but also known organelle-specific factors. In contrast to PVs, ESVs appear to maintain a strong physical and functional link to the ER including recruitment of ribosomes to organelle membranes. Overall the data provide further evidence for the formation of a cyst extracellular matrix with minimal complexity. The mass spectrometry proteomics data have been deposited to the ProteomeXchange Consortium with the dataset identifier PXD000694.
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Affiliation(s)
- Petra B. Wampfler
- Institute of Parasitology, University of Zurich, Zurich, Switzerland
| | - Vinko Tosevski
- Institute of Experimental Immunology, University of Zurich, Zurich, Switzerland
| | - Paolo Nanni
- Functional Genomics Center Zurich, Zurich, Switzerland
| | - Cornelia Spycher
- Institute of Parasitology, University of Zurich, Zurich, Switzerland
- Institute of Parasitology, University of Bern, Bern, Switzerland
- * E-mail: (ABH); (CS)
| | - Adrian B. Hehl
- Institute of Parasitology, University of Zurich, Zurich, Switzerland
- * E-mail: (ABH); (CS)
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13
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Abstract
Giardia duodenalis is a protozoan parasite that causes intestinal disorders. The trophozoites present four pairs of flagella. Here we further analyze the structural organization of the anterior flagella associated structures of G. duodenalis. High resolution scanning electron microscopy of detergent-extracted trophozoites revealed novel aspects of the interaction of the anterior flagella axonemes with the marginal plates. Images of the marginal plates showed that it was located in the anterior region of the parasite, above the crossing point of the anterior flagella axonemes toward the periphery of the cell. Two well distinguished structures were seen associated with the anterior flagella. The first one corresponds to the "dense rods", located just below the axoneme. The second one is a system of filaments located in the upper portion of the flagellum, facing the marginal plates and connecting these two structures. The thickness of the filaments is around 18 nm and they are spaced at intervals of 4-32 nm (average 18 nm). The length of the filaments may vary from 33 to 240 nm. We suggest that this filamentous structure of Giardia may help the dynamics and behavior of the anterior flagella of trophozoites during protozoan motility and adhesion, providing favorable conditions for the establishment of parasitism.
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Affiliation(s)
- Claudia Maia-Brigagão
- Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil, 21941-902
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Busatti HGNO, Alves RJ, Santana-Anjos KG, Gil FF, Cury MC, Vannier-Santos MA, Gomes MA. Effects of metronidazole analogues on Giardia lamblia: experimental infection and cell organization. Diagn Microbiol Infect Dis 2013; 75:160-4. [PMID: 23331963 DOI: 10.1016/j.diagmicrobio.2012.11.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [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: 06/22/2012] [Revised: 10/29/2012] [Accepted: 11/03/2012] [Indexed: 11/18/2022]
Abstract
The chemotherapeutic agents used for the treatment of giardiasis are often associated with adverse side effects and are refractory cases, due to the development of resistant parasites. Therefore the search for new drugs is required. We have previously reported the giardicidal effects of metronidazole (MTZ) and its analogues (MTZ-Ms, MTZ-Br, MTZ-N(3), and MTZ-I) on the trophozoites of Giardia lamblia. Now we evaluated the activity of some giardicidal MTZ analogues in experimental infections in gerbils and its effects on the morphology and ultrastructural organization of Giardia. The giardicidal activity in experimental infections showed ED(50) values significantly lower for MTZ-I and MTZ-Br when compared to MTZ. Transmission electron microscopy was employed to approach the mechanism(s) of action of MTZ analogues upon the protozoan. MTZ analogues were more active than MTZ in changing significantly the morphology and ultrastructure of the parasite. The analogues affected parasite cell vesicle trafficking, autophagy, and triggered differentiation into cysts. These results coupled with the excellent giardicidal activity and lower toxicity demonstrate that these nitroimidazole derivates may be important therapeutic alternatives for combating giardiasis. In addition, our results suggest a therapeutic advantage in obtaining synthetic metronidazole analogues for screening of activities against other infectious agents.
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Affiliation(s)
- Haendel G N O Busatti
- Depto. Parasitologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Av. Antônio Carlos 6627, Belo Horizonte, MG, Brazil
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15
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Hahn J, Seeber F, Kolodziej H, Ignatius R, Laue M, Aebischer T, Klotz C. High sensitivity of Giardia duodenalis to tetrahydrolipstatin (orlistat) in vitro. PLoS One 2013; 8:e71597. [PMID: 23977083 PMCID: PMC3747212 DOI: 10.1371/journal.pone.0071597] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [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: 05/06/2013] [Accepted: 07/06/2013] [Indexed: 11/18/2022] Open
Abstract
Giardiasis, a gastrointestinal disease caused by Giardia duodenalis, is currently treated mainly with nitroimidazoles, primarily metronidazole (MTZ). Treatment failure rates of up to 20 percent reflect the compelling need for alternative treatment options. Here, we investigated whether orlistat, a drug approved to treat obesity, represents a potential therapeutic agent against giardiasis. We compared the growth inhibitory effects of orlistat and MTZ on a long-term in vitro culture adapted G. duodenalis strain, WB-C6, and on a new isolate, 14-03/F7, from a patient refractory to MTZ treatment using a resazurin assay. The giardiacidal concentration of the drugs and their combined in vitro efficacy was determined by median-effect analysis. Morphological changes after treatment were analysed by light and electron microscopy. Orlistat inhibited the in vitro growth of G. duodenalis at low micromolar concentrations, with isolate 14-03/F7 (IC5024h = 2.8 µM) being more sensitive than WB-C6 (IC5024h = 6.2 µM). The effect was significantly more potent compared to MTZ (IC5024h = 4.3 µM and 11.0 µM, respectively) and led to specific undulated morphological alterations on the parasite surface. The giardiacidal concentration of orlistat was >14 µM for 14-03/F7 and >43 µM for WB-C6, respectively. Importantly, the combination of both drugs revealed no interaction on their inhibitory effects. We demonstrate that orlistat is a potent inhibitor of G. duodenalis growth in vitro and kills parasites at concentrations achievable in the gut by approved treatment regimens for obesity. We therefore propose to investigate orlistat in controlled clinical studies as a new drug in giardiasis.
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Affiliation(s)
- Juliane Hahn
- Institute of Pharmacy, Pharmaceutical Biology, Freie Universität Berlin, Berlin, Germany
| | - Frank Seeber
- Mycotic and Parasitic Agents and Mycobacteria, Department of Infectious Diseases, Robert Koch-Institut, Berlin, Germany
| | - Herbert Kolodziej
- Institute of Pharmacy, Pharmaceutical Biology, Freie Universität Berlin, Berlin, Germany
| | - Ralf Ignatius
- Institute of Tropical Medicine and International Health, Charité – Universitätsmedizin Berlin, Berlin, Germany
| | - Michael Laue
- Advanced Light and Electron Microscopy, Centre for Biological Threats and Special Pathogens, Robert Koch-Institut, Berlin, Germany
| | - Toni Aebischer
- Mycotic and Parasitic Agents and Mycobacteria, Department of Infectious Diseases, Robert Koch-Institut, Berlin, Germany
| | - Christian Klotz
- Mycotic and Parasitic Agents and Mycobacteria, Department of Infectious Diseases, Robert Koch-Institut, Berlin, Germany
- * E-mail:
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16
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Schwartz CL, Heumann JM, Dawson SC, Hoenger A. A detailed, hierarchical study of Giardia lamblia's ventral disc reveals novel microtubule-associated protein complexes. PLoS One 2012; 7:e43783. [PMID: 22984443 PMCID: PMC3439489 DOI: 10.1371/journal.pone.0043783] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [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: 05/25/2012] [Accepted: 07/24/2012] [Indexed: 01/01/2023] Open
Abstract
Giardia lamblia is a flagellated, unicellular parasite of mammals infecting over one billion people worldwide. Giardia's two-stage life cycle includes a motile trophozoite stage that colonizes the host small intestine and an infectious cyst form that can persist in the environment. Similar to many eukaryotic cells, Giardia contains several complex microtubule arrays that are involved in motility, chromosome segregation, organelle transport, maintenance of cell shape and transformation between the two life cycle stages. Giardia trophozoites also possess a unique spiral microtubule array, the ventral disc, made of approximately 50 parallel microtubules and associated microribbons, as well as a variety of associated proteins. The ventral disc maintains trophozoite attachment to the host intestinal epithelium. With the help of a combined SEM/microtome based slice and view method called 3View® (Gatan Inc., Pleasanton, CA), we present an entire trophozoite cell reconstruction and describe the arrangement of the major cytoskeletal elements. To aid in future analyses of disc-mediated attachment, we used electron-tomography of freeze-substituted, plastic-embedded trophozoites to explore the detailed architecture of ventral disc microtubules and their associated components. Lastly, we examined the disc microtubule array in three dimensions in unprecedented detail using cryo-electron tomography combined with internal sub-tomogram volume averaging of repetitive domains. We discovered details of protein complexes stabilizing microtubules by attachment to their inner and outer wall. A unique tri-laminar microribbon structure is attached vertically to the disc microtubules and is connected to neighboring microribbons via crossbridges. This work provides novel insight into the structure of the ventral disc microtubules, microribbons and associated proteins. Knowledge of the components comprising these structures and their three-dimensional organization is crucial toward understanding how attachment via the ventral disc occurs in vivo.
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Affiliation(s)
- Cindi L. Schwartz
- Boulder Lab for 3-D Electron Microscopy of Cells, Department of MCD Biology, University of Colorado, Boulder, Colorado, United States of America
| | - John M. Heumann
- Boulder Lab for 3-D Electron Microscopy of Cells, Department of MCD Biology, University of Colorado, Boulder, Colorado, United States of America
| | - Scott C. Dawson
- Department Microbiology, University of California Davis, Davis, California, United States of America
| | - Andreas Hoenger
- Boulder Lab for 3-D Electron Microscopy of Cells, Department of MCD Biology, University of Colorado, Boulder, Colorado, United States of America
- * E-mail:
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17
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Abstract
We investigate the use of wetting films to significantly improve the imaging performance of lensfree pixel super-resolution on-chip microscopy, achieving < 1 µm spatial resolution over a large imaging area of ~24 mm(2). Formation of an ultra-thin wetting film over the specimen effectively creates a micro-lens effect over each object, which significantly improves the signal-to-noise-ratio and therefore the resolution of our lensfree images. We validate the performance of this approach through lensfree on-chip imaging of various objects having fine morphological features (with dimensions of e.g., ≤0.5 µm) such as Escherichia coli (E. coli), human sperm, Giardia lamblia trophozoites, polystyrene micro beads as well as red blood cells. These results are especially important for the development of highly sensitive field-portable microscopic analysis tools for resource limited settings.
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Affiliation(s)
- Onur Mudanyali
- Electrical Engineering Department, University of California, Los Angeles, CA 90095,
USA
| | - Waheb Bishara
- Electrical Engineering Department, University of California, Los Angeles, CA 90095,
USA
| | - Aydogan Ozcan
- Electrical Engineering Department, University of California, Los Angeles, CA 90095,
USA
- Bioengineering Department, University of California, Los Angeles, CA 90095,
USA
- California NanoSystems Institute, University of California, Los Angeles, CA 90095,
USA
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18
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Konrad C, Spycher C, Hehl AB. Selective condensation drives partitioning and sequential secretion of cyst wall proteins in differentiating Giardia lamblia. PLoS Pathog 2010; 6:e1000835. [PMID: 20386711 PMCID: PMC2851657 DOI: 10.1371/journal.ppat.1000835] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [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: 09/14/2009] [Accepted: 02/25/2010] [Indexed: 12/02/2022] Open
Abstract
Controlled secretion of a protective extracellular matrix is required for transmission of the infective stage of a large number of protozoan and metazoan parasites. Differentiating trophozoites of the highly minimized protozoan parasite Giardia lamblia secrete the proteinaceous portion of the cyst wall material (CWM) consisting of three paralogous cyst wall proteins (CWP1–3) via organelles termed encystation-specific vesicles (ESVs). Phylogenetic and molecular data indicate that Diplomonads have lost a classical Golgi during reductive evolution. However, neogenesis of ESVs in encysting Giardia trophozoites transiently provides basic Golgi functions by accumulating presorted CWM exported from the ER for maturation. Based on this “minimal Golgi” hypothesis we predicted maturation of ESVs to a trans Golgi-like stage, which would manifest as a sorting event before regulated secretion of the CWM. Here we show that proteolytic processing of pro-CWP2 in maturing ESVs coincides with partitioning of CWM into two fractions, which are sorted and secreted sequentially with different kinetics. This novel sorting function leads to rapid assembly of a structurally defined outer cyst wall, followed by slow secretion of the remaining components. Using live cell microscopy we find direct evidence for condensed core formation in maturing ESVs. Core formation suggests that a mechanism controlled by phase transitions of the CWM from fluid to condensed and back likely drives CWM partitioning and makes sorting and sequential secretion possible. Blocking of CWP2 processing by a protease inhibitor leads to mis-sorting of a CWP2 reporter. Nevertheless, partitioning and sequential secretion of two portions of the CWM are unaffected in these cells. Although these cysts have a normal appearance they are not water resistant and therefore not infective. Our findings suggest that sequential assembly is a basic architectural principle of protective wall formation and requires minimal Golgi sorting functions. The protozoan Giardia lamblia is the leading cause for parasite-induced diarrhea with significant morbidity in humans and animals world-wide, and is transmitted by water-resistant cysts. Giardia has undergone substantial reductive evolution to a simpler organization than the last common eukaryotic ancestor, which makes it an interesting model to investigate basic cellular mechanisms. Its secretory system lacks a Golgi, but trophozoites induced to differentiate to cysts generate organelles termed encystation-specific vesicles (ESVs). Previous work shows that ESVs are most likely minimal pulsed Golgi-like compartments for exporting pre-sorted cyst wall material. We tested whether the sorting function associated with classical trans Golgi networks was also conserved in these organelles. By tracking immature and processed forms of the three cyst wall proteins during differentiation we discovered a novel sorting function which results in partitioning of ESV cargo and sequential secretion of the cyst wall material. Using live cell imaging we identified reversible formation of condensed cores as a mechanism for cargo partitioning. These observations suggest that the requirement for sequential secretion of extracellular matrix components protecting Giardia during transmission has prevented the complete secondary loss of the machinery to generate Golgi cisterna-like maturation compartments; indeed, the preserved functions have been placed under stage-specific control.
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Affiliation(s)
- Christian Konrad
- Institute of Parasitology, University of Zürich, Zürich, Switzerland
| | - Cornelia Spycher
- Institute of Parasitology, University of Zürich, Zürich, Switzerland
| | - Adrian B. Hehl
- Institute of Parasitology, University of Zürich, Zürich, Switzerland
- * E-mail:
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19
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Abstract
Giardia intestinalis, a common parasitic protist, possesses a complex microtubule cytoskeleton critical for cellular function and transitioning between the cyst and trophozoite life cycle stages. The giardial microtubule cytoskeleton is comprised of highly dynamic and stable structures. Novel microtubule structures include the ventral disc that is essential for the parasite's attachment to the intestinal villi to avoid peristalsis. The completed Giardia genome combined with new molecular genetic tools and live imaging will aid in the characterization and analysis of cytoskeletal dynamics in Giardia. Fundamental areas of giardial cytoskeletal biology remain to be explored and knowledge of the molecular mechanisms of cytoskeletal functioning is needed to better understand Giardia's unique biology and pathogenesis.
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Affiliation(s)
- Scott C Dawson
- Department of Microbiology, One Shields Avenue, UC Davis, Davis, CA 95616, USA
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20
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Abstract
Previous investigations have proved that diplomonads have primitive cell nuclei and lack a nucleolus. We determined the distribution of ribosomal DNA (rDNA) in diplomonad nuclei that lacked a nucleolus. Giardia lamblia was used as the experimental organism with Euglena gracilis as the control. The distribution of rDNA was demonstrated indirectly by the modified Ag-I silver technique that can indicate specifically the nucleolus organizing region (NOR) by both light and electron microscopy. In ultrathin sections of silver stained Euglena cells, all silver grains were concentrated in the fibrosa of the nucleolus, while no silver grains were found in the cytoplasm, nucleoplasm, condensed chromosomes or pars granulosa of the nucleus. In the silver stained Giardia cells, no nucleolus was found, but a few silver grains were scattered in the nucleus. This suggests that the rDNA of Giardia does not form an NOR-like structure and that its nucleus is in a primitive state.
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Affiliation(s)
- J Guo
- College of Life Science, Nanjing Normal University, Nanjing, 210097, P.R. China.
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21
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Šmíd O, Matušková A, Harris SR, Kučera T, Novotný M, Horváthová L, Hrdý I, Kutějová E, Hirt RP, Embley TM, Janata J, Tachezy J. Reductive evolution of the mitochondrial processing peptidases of the unicellular parasites trichomonas vaginalis and giardia intestinalis. PLoS Pathog 2008; 4:e1000243. [PMID: 19096520 PMCID: PMC2597178 DOI: 10.1371/journal.ppat.1000243] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [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: 09/08/2008] [Accepted: 11/18/2008] [Indexed: 11/18/2022] Open
Abstract
Mitochondrial processing peptidases are heterodimeric enzymes (alpha/betaMPP) that play an essential role in mitochondrial biogenesis by recognizing and cleaving the targeting presequences of nuclear-encoded mitochondrial proteins. The two subunits are paralogues that probably evolved by duplication of a gene for a monomeric metallopeptidase from the endosymbiotic ancestor of mitochondria. Here, we characterize the MPP-like proteins from two important human parasites that contain highly reduced versions of mitochondria, the mitosomes of Giardia intestinalis and the hydrogenosomes of Trichomonas vaginalis. Our biochemical characterization of recombinant proteins showed that, contrary to a recent report, the Trichomonas processing peptidase functions efficiently as an alpha/beta heterodimer. By contrast, and so far uniquely among eukaryotes, the Giardia processing peptidase functions as a monomer comprising a single betaMPP-like catalytic subunit. The structure and surface charge distribution of the Giardia processing peptidase predicted from a 3-D protein model appear to have co-evolved with the properties of Giardia mitosomal targeting sequences, which, unlike classic mitochondrial targeting signals, are typically short and impoverished in positively charged residues. The majority of hydrogenosomal presequences resemble those of mitosomes, but longer, positively charged mitochondrial-type presequences were also identified, consistent with the retention of the Trichomonas alphaMPP-like subunit. Our computational and experimental/functional analyses reveal that the divergent processing peptidases of Giardia mitosomes and Trichomonas hydrogenosomes evolved from the same ancestral heterodimeric alpha/betaMPP metallopeptidase as did the classic mitochondrial enzyme. The unique monomeric structure of the Giardia enzyme, and the co-evolving properties of the Giardia enzyme and substrate, provide a compelling example of the power of reductive evolution to shape parasite biology.
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Affiliation(s)
- Ondřej Šmíd
- Department of Parasitology, Faculty of Science, Charles University in Prague, Prague, Czech Republic
| | - Anna Matušková
- Institute of Microbiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Simon R. Harris
- Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Tomáš Kučera
- Institute of Microbiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Marián Novotný
- Department of Parasitology, Faculty of Science, Charles University in Prague, Prague, Czech Republic
| | - Lenka Horváthová
- Department of Parasitology, Faculty of Science, Charles University in Prague, Prague, Czech Republic
| | - Ivan Hrdý
- Department of Parasitology, Faculty of Science, Charles University in Prague, Prague, Czech Republic
| | - Eva Kutějová
- Institute of Molecular Biology, Slovak Academy of Sciences, Bratislava, Slovak Republic
| | - Robert P. Hirt
- Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - T. Martin Embley
- Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Jiří Janata
- Institute of Microbiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Jan Tachezy
- Department of Parasitology, Faculty of Science, Charles University in Prague, Prague, Czech Republic
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22
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Abstract
BACKGROUND The parasite Giardia lamblia must remain attached to the host small intestine in order to proliferate and subsequently cause disease. However, little is known about the factors that may cause detachment in vivo, such as changes in the aqueous environment. Osmolality within the proximal small intestine can vary by nearly an order of magnitude between host fed and fasted states, while pH can vary by several orders of magnitude. Giardia cells are known to regulate their volume when exposed to changes in osmolality, but the short-timescale effects of osmolality and pH on parasite attachment are not known. METHODOLOGY AND PRINCIPAL FINDINGS We used a closed flow chamber assay to test the effects of rapid changes in media osmolality, tonicity, and pH on Giardia attachment to both glass and C2(Bbe)-1 intestinal cell monolayer surfaces. We found that Giardia detach from both surfaces in a tonicity-dependent manner, where tonicity is the effective osmolality experienced by the cell. Detachment occurs with a characteristic time constant of 25 seconds (SD = 10 sec, n = 17) in both hypo- and hypertonic media but is otherwise insensitive to physiologically relevant changes in media composition and pH. Interestingly, cells that remain attached are able to adapt to moderate changes in tonicity. By exposing cells to a timed pattern of tonicity variations and adjustment periods, we found that it is possible to maximize the tonicity change experienced by the cells, overcoming the adaptive response and resulting in extensive detachment. CONCLUSIONS AND SIGNIFICANCE These results, conducted with human-infecting Giardia on human intestinal epithelial monolayers, highlight the ability of Giardia to adapt to the changing intestinal environment and suggest new possibilities for treatment of giardiasis by manipulation of tonicity in the intestinal lumen.
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Affiliation(s)
- Wendy R. Hansen
- Biophysics Graduate Group, University of California, Berkeley, California, United States of America
| | - Daniel A. Fletcher
- Biophysics Graduate Group, University of California, Berkeley, California, United States of America
- Department of Bioengineering, University of California, Berkeley, California, United States of America
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23
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Gaechter V, Schraner E, Wild P, Hehl AB. The single dynamin family protein in the primitive protozoan Giardia lamblia is essential for stage conversion and endocytic transport. Traffic 2007; 9:57-71. [PMID: 17892527 DOI: 10.1111/j.1600-0854.2007.00657.x] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Dynamins are universally conserved large guanosine triphosphatases, which function as mechanoenzymes in membrane scission. The primitive protozoan Giardia lamblia has a single dynamin-related protein (GlDRP) with an unusual domain structure. Giardia lacks a Golgi apparatus but generates transient Golgi-like delay compartments dubbed encystation-specific vesicles (ESVs), which serve to accumulate and mature cyst wall proteins during differentiation to infectious cyst forms. Here, we analyze the function of GlDRP during growth and encystation and demonstrate that it relocalizes from peripheral endosomal-lysosomal compartments to nascent ESVs. We show that GlDRP is necessary for secretion of the cyst wall material and ESV homeostasis. Expression of a dominant-negative GlDRP variant does not interfere with ESV formation but blocks cyst formation completely prior to regulated exocytosis. GlDRP colocalizes with clathrin at the cell periphery and is necessary for endocytosis of surface proteins to endosomal-lysosomal organelles in trophozoites. Electron microscopy and live cell imaging reveal gross morphological changes as well as functional impairment of the endocytic system in cells expressing the dominant-negative GlDRP. Thus, giardial DRP plays a key role in two distinct trafficking pathways and in organelle homeostasis, both essential functions for the proliferation of the parasite in the gut and its transmission to a new host.
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Affiliation(s)
- Verena Gaechter
- Institute of Parasitology, University of Zürich, Winterthurerstrasse 266a, 8057 Zürich, Switzerland
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24
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Vahrmann A, Sarić M, Koebsch I, Scholze H. alpha14-Giardin (annexin E1) is associated with tubulin in trophozoites of Giardia lamblia and forms local slubs in the flagella. Parasitol Res 2007; 102:321-6. [PMID: 17938962 DOI: 10.1007/s00436-007-0758-6] [Citation(s) in RCA: 20] [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: 07/20/2007] [Accepted: 09/18/2007] [Indexed: 11/25/2022]
Abstract
In a previous study, we reported that the novel annexin XX1 (annexin E1), identical to alpha14-giardin, is specifically localized to the flagella and to the median body of the trophozoites. However, the mode of interaction and the direct partners involved remained unclear. In the present study, we show that alpha4-giardin obviously does not evenly distribute over the full length of the axonemes, but rather, resides at local slubs near the proximal part and the ends of the flagella. In immunocytochemical co-localization studies, the anti-giardin primary antibody exclusively reacted with distinct regions of the flagella in permeabilized cells, whereas the anti-tubulin antibody bound to all areas of the axonemes in the cells and to isolated cytoskeletons. Isolated cytoskeletons did not react with anti-giardin antibodies. alpha14-Giardin itself is able to assemble to multimeric structures. Taken together, our findings suggest that alpha14-giardin adheres to microtubules of the flagella via self-assembly that may regulated by Ser/Thr-phosphorylation.
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Affiliation(s)
- A Vahrmann
- Department of Biology/Chemistry, Biochemistry, University of Osnabrueck, 49069, Osnabrueck, Germany
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25
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[Chronic infectious bowel diseases. Lambliasis]. Z Gastroenterol 2007; 45:672. [PMID: 17710772] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
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26
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Vidal F, Vidal JC, Gadelha APR, Lopes CS, Coelho MGP, Monteiro-Leal LH. Giardia lamblia: The effects of extracts and fractions from Mentha x piperita Lin. (Lamiaceae) on trophozoites. Exp Parasitol 2007; 115:25-31. [PMID: 16843460 DOI: 10.1016/j.exppara.2006.05.001] [Citation(s) in RCA: 34] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2005] [Revised: 05/08/2006] [Accepted: 05/09/2006] [Indexed: 11/30/2022]
Abstract
Giardia lamblia is a parasite that causes giardiasis in humans and other mammals. The common treatment includes different classes of drugs, which were described to produce unpleasant side effects. Mentha x piperita, popularly known as peppermint, is a plant that is frequently used in the popular medicine to treat gastrointestinal symptoms. We examined the effects of crude extracts and fractions from peppermint against G. lamblia (ATCC 30888) on the basis of trophozoite growth, morphology and adherence studies. The methanolic, dichloromethane and hexanic extracts presented IC(50) values of 0.8, 2.5 and 9.0microg/ml after 48h of incubation, respectively. The aqueous extract showed no effect against the trophozoites with an IC(50)>100microg/ml. The aqueous fraction presented a moderate activity with an IC(50) of 45.5microg/ml. The dichloromethane fraction showed the best antigiardial activity, with an IC(50) of 0.75microg/ml after 48h of incubation. The morphological and adhesion assays showed that this fraction caused several alterations on plasma membrane surface of the parasite and inhibited the adhesion of G. lamblia trophozoites. Cytotoxic assays showed that Mentha x piperita presented no toxic effects on the intestinal cell line IEC-6. Our results demonstrated antigiardial activity of Mentha x piperita, indicating its potential value as therapeutic agent against G. lamblia infections.
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Affiliation(s)
- F Vidal
- Department of Histology and Embryology, Laboratory of Microscopy and Image Processing, State University of Rio de Janeiro, Av. Prof. Manoel de Abreu, 444, 3 degrees andar, Maracanã, Rio de Janeiro, RJ 20550-170, Brazil
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Sagolla MS, Dawson SC, Mancuso JJ, Cande WZ. Three-dimensional analysis of mitosis and cytokinesis in the binucleate parasite Giardia intestinalis. J Cell Sci 2006; 119:4889-900. [PMID: 17105767 DOI: 10.1242/jcs.03276] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In the binucleate parasite Giardia intestinalis, two diploid nuclei and essential cytoskeletal structures including eight flagella are duplicated and partitioned into two daughter cells during cell division. The mechanisms of mitosis and cytokinesis in the binucleate parasite Giardia are poorly resolved, yet have important implications for the maintenance of genetic heterozygosity. To articulate the mechanism of mitosis and the plane of cell division, we used three-dimensional deconvolution microscopy of each stage of mitosis to monitor the spatial relationships of conserved cytological markers to the mitotic spindles, the centromeres and the spindle poles. Using both light- and transmission electron microscopy, we determined that Giardia has a semi-open mitosis with two extranuclear spindles that access chromatin through polar openings in the nuclear membranes. In prophase, the nuclei migrate to the cell midline, followed by lateral chromosome segregation in anaphase. Taxol treatment results in lagging chromosomes and half-spindles. Our analysis supports a nuclear migration model of mitosis with lateral chromosome segregation in the left-right axis and cytokinesis along the longitudinal plane (perpendicular to the spindles), ensuring that each daughter inherits one copy of each parental nucleus with mirror image symmetry. Fluorescence in situ hybridization (FISH) to an episomal plasmid confirms that the nuclei remain separate and are inherited with mirror image symmetry.
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Affiliation(s)
- Meredith S Sagolla
- Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, CA 94720, USA
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Tian XF, Wei R, Yang ZH, Lu SQ. [The injury of metronidazole on morphology of Giardia lamblia in vitro]. Zhongguo Ji Sheng Chong Xue Yu Ji Sheng Chong Bing Za Zhi 2006; 24:387-8. [PMID: 17361825] [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: 05/14/2023]
Abstract
Trophozoites of Giardia lamblia were axenically cultivated with modified TYI-S-33 medium contained 500 microg/ml metronidazole (12h LC50). The morphology of drug-treated trophozoites was observed with light and electron micro-scopes at 2, 4, 8, 12 h respectively. The light microscopy revealed that the trophozoites treated with MTZ showed swollen, detached from the wall of the culture tube, and were with vacuoles in the cytoplasm. Movement of the flagella become slowly or stopped. Electronic microscopy showed that the trophozoites were swollen and deformed; lots of vacuoles were seen in the cytoplasm; the contents of cytoplasm were depleted and the nuclei deformed. This study indicated that MTZ has injured the morphology of G. lamblia.
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Affiliation(s)
- Xi-feng Tian
- Department of Parasitology, North China Coal Medical College, Tangshan, 063000, China
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29
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Pérez-Arriaga L, Mendoza-Magaña ML, Cortés-Zárate R, Corona-Rivera A, Bobadilla-Morales L, Troyo-Sanromán R, Ramírez-Herrera MA. Cytotoxic effect of curcumin on Giardia lamblia trophozoites. Acta Trop 2006; 98:152-61. [PMID: 16678115 DOI: 10.1016/j.actatropica.2006.03.005] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.4] [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: 02/02/2006] [Revised: 03/24/2006] [Accepted: 03/30/2006] [Indexed: 11/21/2022]
Abstract
Giardia lamblia is one of the most important worldwide causes of intestinal infections produced by protozoa. Thus, the search for new alternative therapeutic approaches for this parasitic disease is very important. Common drugs used to control and eradicate this infection, frequently exhibit side effects that force patients to abandon treatment. The present work evaluates the anti-protozoan activity of curcumin, the main constituent of turmeric. Axenic G. lamblia (Portland 1 strain) cultures were exposed to different concentrations of curcumin. Its effects were evaluated on parasite growth, adhesion capacity and parasite morphology. We also evaluated the capacity of curcumin to induce an apoptosis-like effect. All curcumin concentrations inhibited trophozoite growth and adhesion in more than 50% in dose and time dependent manner. Morphological changes were described as protrusions formed under the cytoplasmic membrane, deformation due to swelling and cell agglutination. Curcumin induced apoptosis-like nuclear staining in dose and time dependent manner. In conclusion, curcumin exhibited a cytotoxic effect in G. lamblia inhibiting the parasite growth and adherent capacity, induced morphological alterations, provoked apoptosis-like changes. Future in vitro and in vivo experiments are endowed to elucidate the effect of curcumin in an experimental model of G. lamblia infection, analyze the involvement of ion channels in the swelling effect of curcumin during an apparent osmotic deregulation in G. lamblia trophozoites. This will lead to the proposal of the action mechanism of curcumin as well as the description of mechanism involved during the activation process for the apoptotic-like effect.
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Affiliation(s)
- L Pérez-Arriaga
- Departamento de Fisiología, Centro Universitario de Ciencias de la Salud, Universidad de Guadalajara, Sierra Mojada 950, Guadalajara, Jalisco, CP 44340, México
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Nohynková E, Tumová P, Kulda J. Cell division of Giardia intestinalis: flagellar developmental cycle involves transformation and exchange of flagella between mastigonts of a diplomonad cell. Eukaryot Cell 2006; 5:753-61. [PMID: 16607022 PMCID: PMC1459668 DOI: 10.1128/ec.5.4.753-761.2006] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2005] [Accepted: 01/23/2006] [Indexed: 11/20/2022]
Abstract
Giardia intestinalis is a binucleated diplomonad possessing four pairs of flagella of distinct location and function. Its pathogenic potential depends on the integrity of a complex microtubular cytoskeleton that undergoes a profound but poorly understood reorganization during cell division. We examined the cell division of G. intestinalis with the aid of light and electron microscopy and immunofluorescence methods and present here new observations on the reorganization of the flagellar apparatus in the dividing Giardia. Our results demonstrated the presence of a flagellar maturation process during which the flagella migrate, assume different position, and transform to different flagellar types in progeny until their maturation is completed. For each newly assembled flagellum it takes three cell cycles to become mature. The mature flagellum of Giardia is the caudal one that possesses a privileged basal body at which the microtubules of the adhesive disk nucleate. In contrast to generally accepted assumption that each of the two diplomonad mastigonts develops separately, we found that they are developmentally linked, exchanging their cytoskeletal components at the early phase of mitosis. The presence of the flagellar maturation process in a metamonad protist Giardia suggests that the basal body or centriole maturation is a universal phenomenon that may represent one of the core processes in a eukaryotic cell.
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Affiliation(s)
- Eva Nohynková
- Department of Tropical Medicine, 1st Faculty of Medicine, Charles University in Prague, Studnickova 7, 128 00 Prague 2, Czech Republic.
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Müller J, Rühle G, Müller N, Rossignol JF, Hemphill A. In vitro effects of thiazolides on Giardia lamblia WB clone C6 cultured axenically and in coculture with Caco2 cells. Antimicrob Agents Chemother 2006; 50:162-70. [PMID: 16377682 PMCID: PMC1346829 DOI: 10.1128/aac.50.1.162-170.2006] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.3] [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: 11/20/2022] Open
Abstract
The thiazolides represent a novel class of anti-infective drugs, with the nitrothiazole nitazoxanide [2-acetolyloxy-N-(5-nitro 2-thiazolyl) benzamide] (NTZ) as the parent compound. NTZ exhibits a broad spectrum of activities against a wide variety of helminths, protozoa, and enteric bacteria infecting animals and humans. In vivo, NTZ is rapidly deacetylated to tizoxanide (TIZ), which exhibits similar activities. We have here comparatively investigated the in vitro effects of NTZ, TIZ, a number of other modified thiazolides, and metronidazole (MTZ) on Giardia lamblia trophozoites grown under axenic culture conditions and in coculture with the human cancer colon cell line Caco2. The modifications of the thiazolides included, on one hand, the replacement of the nitro group on the thiazole ring with a bromide, and, on the other hand, the differential positioning of methyl groups on the benzene ring. Of seven compounds with a bromo instead of a nitro group, only one, RM4820, showed moderate inhibition of Giardia proliferation in axenic culture, but not in coculture with Caco2 cells, with a 50% inhibitory concentration (IC50) of 18.8 microM; in comparison, NTZ and tizoxanide had IC50s of 2.4 microM, and MTZ had an IC50 of 7.8 microM. Moreover, the methylation or carboxylation of the benzene ring at position 3 resulted in a significant decrease of activity, and methylation at position 5 completely abrogated the antiparasitic effect of the nitrothiazole compound. Trophozoites treated with NTZ showed distinct lesions on the ventral disk as soon as 2 to 3 h after treatment, whereas treatment with metronidazole resulted in severe damage to the dorsal surface membrane at later time points.
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Affiliation(s)
- Joachim Müller
- Institute of Parasitology, University of Bern, Länggass-Strasse 122, CH-3012 Bern, Switzerland
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Hausen MA, Freitas JCM, Monteiro-Leal LH. The effects of metronidazole and furazolidone during Giardia differentiation into cysts. Exp Parasitol 2006; 113:135-41. [PMID: 16473351 DOI: 10.1016/j.exppara.2005.12.009] [Citation(s) in RCA: 16] [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: 06/10/2005] [Revised: 12/20/2005] [Accepted: 12/21/2005] [Indexed: 10/25/2022]
Abstract
The protozoon Giardia lamblia infects millions of people worldwide, most of them in underdeveloped countries, where it is frequently a hyperendemic disease. The search for an effective anti-Giardia treatment has been intense, but recurrent infections, virulence factors, and drug resistance imposed obstacles in the achievement of an efficient medication. Most papers about drug effects in Giardia are related to the trophozoite form, although viable cysts, the infective forms, are continuously eliminated in the stools during the treatment. Supported by this knowledge, we analyzed the inhibitory effects of metronidazole (MZ) and furazolidone (FZ) on the differentiation of Giardia into cysts and its viability. The presence of cavities, lamellar bodies and thread-like structures were the most frequent morphological alterations. The results showed also that FZ was more effective by 50% than MZ in inhibiting in vitro cyst differentiation.
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Affiliation(s)
- Moema A Hausen
- Universidade do Estado do Rio de Janeiro, Instituto de Biologia, Departamento de Histologia e Embriologia, Lab. de Microscopia e Processamento de Imagens, Rio de Janeiro, RJ, Brazil
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Ponce-Macotela M, Rufino-González Y, González-Maciel A, Reynoso-Robles R, Martínez-Gordillo MN. Oregano (Lippia spp.) kills Giardia intestinalis trophozoites in vitro: antigiardiasic activity and ultrastructural damage. Parasitol Res 2006; 98:557-60. [PMID: 16425064 DOI: 10.1007/s00436-005-0082-y] [Citation(s) in RCA: 17] [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: 10/20/2005] [Accepted: 10/28/2005] [Indexed: 10/25/2022]
Abstract
In the world, giardiosis is still a very important parasitic disease; only in Asia, Africa and America, there are more than 200 million of infected people in a year. The usual treatments are drugs that produce undesirable secondary effects, perhaps favouring the resistant strain selection. One alternative is to research compounds from plants used as antidiarrhoeic or antiparasitic in the traditional medicine. In a previous work, we found that Lippia beriandieri (Oregano) revealed to be more potent than tinidazole, a common antigiardiasic drug. In this current work, we tested the cell viability by re-culture and reduction of MTT-tetrazolium salts to MTT-formazan, and we showed the effect of oregano ethanolic extracts against Giardia intestinalis (synonyms: Giardia duodenalis, Giardia lamblia) trophozoites at concentrations ranging form 58 to 588 microg. We demonstrated the ultrastructural injury produced by oregano extracts in this parasite. Trophozoites lost their size and shape and showed damage in nucleus structure, perhaps by breaking the pattern of nucleoskeleton proteins.
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Affiliation(s)
- Martha Ponce-Macotela
- Parasitología Experimental, Instituto Nacional de Pediatría, Insurgentes Sur, C.P. 04530, No. 3700-C, México, D.F., Mexico
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Abstract
Giardia lamblia, a flagellated protist, is the parasite most commonly found in the intestinal tract of humans and other mammals causing a disease known as giardiasis. This parasite presents several cytoskeletal structures whose major components are microtubules, namely: the ventral adhesive disk, eight flagella axonemes, the median body, and funis. However, the cytoskeletal filamentous structures are poorly understood, and therefore, less studied. In the present work, we used actin-interacting drugs such as cytochalasin B and D to investigate their effects on Giardia ultrastructure. Axenically grown G. lamblia trophozoites were treated with these drugs and analyzed by fluorescence microscopy and scanning and transmission electron microscopy. It was observed that trophozoites became completely misshapen, detached from the glass surface, and failed to complete cell division. The main alterations observed included: (1) disk fragmentation, (2) presence of large vacuoles, (3) alterations in flagella number and flagella internalization, (4) blocked cytokinesis but not the karyokinesis, and (5) presence of membrane undulations and blebs. These findings are discussed.
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Affiliation(s)
- Gladys Corrêa
- Laboratório de Ultraestrutura Celular, Universidade Santa Ursula, Rio de Janeiro, Brazil.
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35
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Tian XF, Lu SQ, Liu YM, Wang FY, Huang S. [Effect of dihydroartemisinin on ultrastructure of Giardia lamblia in vitro]. Zhongguo Ji Sheng Chong Xue Yu Ji Sheng Chong Bing Za Zhi 2005; 23:292-5. [PMID: 16562481] [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: 05/08/2023]
Abstract
OBJECTIVE To study the in vitro effect of dihydroartemisinin (DHA) on Giardia lamblia. METHODS Trophozoites of G. lamblia were cultivated with modified TYI-S-33 medium that contains dihydroartemisinin (DHA). The trophozoites were morphologically observed respectively with light and electron microscopes after treated with the drug. RESULTS The mortality increased with the prolongation of the time of the drug action and the increase of drug concentration (P<0.01). While at the same concentration of 100 microg/ml, the mortality increased from 46.6% for 12 h to 100% for 24 h (P<0.05). For 12 h, the mortality of G. lamblia was from 46.6% at concentration of 100 microg/ml to 100% at 200microg/ml. Under optical microscope, deformation and swelling of the parasites were observed when treated with DHA for 12, 24 and 48 h. Movement of the flagella became slow or stopped. Under electron microscope, the trophozoites were swollen and deformed, vacuoles were seen in the cytoplasm, and the cell membrane ruptured and fell off. The cytoplasm protrusions appeared on the surface of the plasma membrane. The adhesive disc changed into large bubbles and the perinuclear space became wider and the deformed nucleus was seen. CONCLUSION DHA shows a strong impairment on the plasma membrane and cytoskeleton of Giardia lamblia.
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Affiliation(s)
- Xi-feng Tian
- Institute of Microbiology & Epidemiology, Academy of Military Medical Sciences, Beijing, China
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Müller N, von Allmen N. Recent insights into the mucosal reactions associated with Giardia lamblia infections. Int J Parasitol 2005; 35:1339-47. [PMID: 16182298 DOI: 10.1016/j.ijpara.2005.07.008] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.9] [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: 05/20/2005] [Revised: 07/22/2005] [Accepted: 07/27/2005] [Indexed: 01/18/2023]
Abstract
Giardia lamblia is an intestinal protozoan parasite infecting humans and various other mammalian hosts. The most important clinical signs of giardiasis are diarrhoea and malabsorption. Giardia lamblia is able to undergo continuous antigenic variation of its major surface antigen, named VSP (variant surface protein). While intestinal antibodies, and more specifically anti-VSP IgA antibodies, were proven to be involved in modulating antigenic variation of the parasite the participation of the local antibody response in control of the parasite infection is still controversial. Conversely, previous studies based on experimental infections in mice showed that cellular immune mechanisms are essential for elimination of the parasite from its intestinal habitat. Furthermore, recent data indicated that inflammatory mast cells have a potential to directly, or indirectly, interfere in duodenal growth of G. lamblia trophozoites. However, this finding was challenged by other reports, which did not find a correlation between intestinal inflammation and resistance to infection. Since intestinal infiltration of inflammatory cells and/or CD8+T-cells were demonstrated to coincide with villus-shortening and crypt hyperplasia immunological reactions were considered to be a potential factor of pathogenesis in giardiasis. The contribution of physiological factors to pathogenesis was essentially assessed in vitro by co-cultivation of G. lamblia trophozoites with epithelial cell lines. By using this in vitro model, molecular (through surface lectins) and mechanical (through ventral disk) adhesion of trophozoites to the epithelium was shown to be crucial for increased epithelial permeability. This phenomenon as well as other Giardia-induced intestinal abnormalities such as loss of intestinal brush border surface area, villus flattening, inhibition of disaccharidase activities, and eventually also overgrowth of the enteric bacterial flora seem to be involved in the pathophysiology of giardiasis. However, it remains to be elucidated whether at least part of these pathological effects are causatively linked to the clinical manifestation of the disease.
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Affiliation(s)
- N Müller
- Institute of Parasitology, Länggass-Str. 122, CH-3012 Bern, Switzerland.
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Dolezal P, Smíd O, Rada P, Zubácová Z, Bursać D, Suták R, Nebesárová J, Lithgow T, Tachezy J. Giardia mitosomes and trichomonad hydrogenosomes share a common mode of protein targeting. Proc Natl Acad Sci U S A 2005; 102:10924-9. [PMID: 16040811 PMCID: PMC1182405 DOI: 10.1073/pnas.0500349102] [Citation(s) in RCA: 126] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Mitochondria are archetypal organelles of endosymbiotic origin in eukaryotic cells. Some unicellular eukaryotes (protists) were considered to be primarily amitochondrial organisms that diverged from the eukaryotic lineage before the acquisition of the premitochondrial endosymbiont, but their amitochondrial status was recently challenged by the discovery of mitochondria-like double membrane-bound organelles called mitosomes. Here, we report that proteins targeted into mitosomes of Giardia intestinalis have targeting signals necessary and sufficient to be recognized by the mitosomal protein import machinery. Expression of these mitosomal proteins in Trichomonas vaginalis results in targeting to hydrogenosomes, a hydrogen-producing form of mitochondria. We identify, in Giardia and Trichomonas, proteins related to the component of the translocase in the inner membrane from mitochondria and the processing peptidase. A shared mode of protein targeting supports the hypothesis that mitosomes, hydrogenosomes, and mitochondria represent different forms of the same fundamental organelle having evolved under distinct selection pressures.
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Affiliation(s)
- Pavel Dolezal
- Department of Parasitology, Charles University, Vinicna 7, 128 44 Prague 2, Czech Republic
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Sant'Anna C, Campanati L, Gadelha C, Lourenço D, Labati-Terra L, Bittencourt-Silvestre J, Benchimol M, Cunha-e-Silva NL, De Souza W. Improvement on the visualization of cytoskeletal structures of protozoan parasites using high-resolution field emission scanning electron microscopy (FESEM). Histochem Cell Biol 2005; 124:87-95. [PMID: 15995880 DOI: 10.1007/s00418-005-0786-1] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/21/2005] [Indexed: 10/25/2022]
Abstract
The association of high resolution field emission scanning electron microscopy (FESEM), with a more efficient system of secondary electron (SE) collection and in-lens specimen position, provided a great improvement in the specimen's topographical contrast and in the generation of high-resolution images. In addition, images obtained with the use of the high-resolution backscattered electrons (BSE) detector provided a powerful tool for immunocytochemical analysis of biological material. In this work, we show the contribution of the FESEM to the detailed description of cytoskeletal structures of the protozoan parasites Herpetomonas megaseliae, Trypanosoma brucei and Giardia lamblia. High-resolution images of detergent extracted H. megaseliae and T. brucei showed the profile of the cortical microtubules, also known as sub-pellicular microtubules (SPMT), and protein bridges cross-linking them. Also, it was possible to visualize fine details of the filaments that form the lattice-like structure of the paraflagellar rod (PFR) and its connection with the axoneme. In G. lamblia, it was possible to observe the intricate structure of the adhesive disk, funis (a microtubular array) and other cytoskeletal structures poorly described previously. Since most of the stable cytoskeletal structures of this protozoan rely on tubulin, we used the BSE images to accurately map immunolabeled tubulin in its cytoskeleton. Our results suggest that the observation of detergent extracted parasites using FESEM associated to backscattered analysis of immunolabeled specimens represents a new approach for the study of parasite cytoskeletal elements and their protein associations.
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Affiliation(s)
- Celso Sant'Anna
- Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro CCS, Rio de Janeiro, bloco G, Cidade Universitária, 21949-900, Brazil
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Mariante RM, Vancini RG, Melo AL, Benchimol M. Giardia lamblia: Evaluation of the in vitro effects of nocodazole and colchicine on trophozoites. Exp Parasitol 2005; 110:62-72. [PMID: 15804380 DOI: 10.1016/j.exppara.2005.01.007] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [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: 08/10/2004] [Revised: 01/18/2005] [Accepted: 01/19/2005] [Indexed: 11/20/2022]
Abstract
Giardia lamblia is the most commonly detected parasite in the intestinal tract of humans and other mammals causing giardiasis. Giardia presents several cytoskeletal structures with microtubules as major components such as the ventral adhesive disk, eight flagella axonemes, the median body and funis. Many drugs have already been tested as antigiardial agents, such as albendazole and mebendazole, which act by specifically inhibiting tubulin polymerization and hence microtubule assembly. In the present work, we used the microtubule inhibitors nocodazole and colchicine in order to investigate their direct and indirect effects on Giardia ultrastructure and attachment to the glass surface, respectively. Axenically grown G. lamblia trophozoites were treated with nocodazole or colchicine for different time intervals and analyzed by light and electron microscopy. It was observed that trophozoites became completely misshapen, detached from the glass surface and failed to complete cell division. The main alterations observed included disc fragmentation, presence of large vacuoles, and appearance of electrondense deposits made of tubulin. The cytokinesis was blocked, but not the karyokinesis, and membrane blebs were observed. These findings show that Giardia behavior and cytoskeleton are clearly affected by the commonly used microtubule targetting agents colchicine and nozodazole.
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Affiliation(s)
- Rafael Meyer Mariante
- Programa de Ciências Morfológicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
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Abstract
Giardia lamblia is an intestinal parasite of several mammals. The most striking feature of Giardia is the presence of a complex and unique cytoskeleton, and among its components the median body (MB) is the least defined microtubular structure. In the present study, we used a technique that allowed the removal of the plasma membrane and observation of cytoskeletal structures by both routine scanning electron microscopy (SEM) and field emission high resolution SEM. This technique permitted new observations such as details and insights of the median bodies, not previously described or controversial in the literature. Light microscopy after Panotic staining, immunofluorescence microscopy using several antibodies, and thin sections were also used to better characterized the Giardia MB. The new observations concerning the median bodies were : (1) they are not one or two structures, but varied in number, shape and position ; (2) they were found in mitotic and interphasic trophozoites, in disagreement with previous works ; (3) they were present in about 80 % of the cells, and not in 50 % of the cells, as previously described ; (4) they could be connected either to the plasma membrane, to the adhesive disc, and caudal flagella, and thus they are not completely free in the cells, as published before ; (5) they can protrude the cell surface ; (6) their microtubules react with several anti-tubulin and -beta giardin antibodies. These observations add new data on the scarce literature and to this largely understudied cell structure.
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Affiliation(s)
- Bruno Piva
- Universidade Santa Ursula, Laboratório de Ultraestrutura Celular, Rio de Janeiro, Brazil
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Hassan SMT, Maache M, de la Guardia RD, Córdova OM, García JRG, Galiana M, Acuña Castroviejo D, Martins M, Osuna A. BINDING PROPERTIES AND IMMUNOLOCALIZATION OF A FATTY ACID–BINDING PROTEIN IN GIARDIA LAMBLIA. J Parasitol 2005; 91:284-92. [PMID: 15986602 DOI: 10.1645/ge-3352] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [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: 11/10/2022] Open
Abstract
We describe here a fatty acid-binding protein (FABP) isolated and purified from the parasitic protozoon Giardia lamblia. The protein has a molecular mass of 8 kDa and an isoelectric point of 4.96. A Scatchard analysis of the data at equilibrium revealed a dissociation constant of 3.12 x 10(-8) M when the labeled oleic acid was displaced by a 10-fold greater concentration of unlabeled oleic acid. Testosterone, sodium desoxycholate, taurocholate, metronidazol, and alpha-tocopherol, together with butyric, arachidonic, palmitic, retinoic, and glycocholic acids, were also bound to the protein. Assays with polyclonal antibodies revealed that the protein is located in the ventral disk and also appears in the dorsal membrane, the cytoplasm, and in the vicinity of the lipid vacuoles.
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Affiliation(s)
- S M T Hassan
- Instituto de Biotecnología, Universidad de Granada, Campus Universitario de Fuentenueva, E-18071 Granada, Spain
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Abstract
Mitosis in Giardia is poorly understood. Until today, it is still controversial whether Giardia divides with a mirror-image symmetry (ventral-ventral or dorsal-dorsal) or in a dorsal-ventral mode. Here, we report the different modes by which cytokinesis takes place in Giardia lamblia. To determine how Giardia divides, video microscopy, scanning electron microscopy, semi-thick sections and freeze-fracture replicas were analyzed by transmission electron microscopy. Between 12 and 15% of the cells cultivated for 24-48 h were found in the process of division. Three types of cytokinesis were found: (1) ventral-ventral, where the discs face each other; (2) dorsal-dorsal, where the discs are in opposite directions; and (3) ventral-dorsal. Giardia divides with mirror-image symmetry either in ventral-ventral or dorsal-dorsal modes. During ventral-ventral type of division, Giardia becomes detached and swims freely in the culture medium, whereas, in the other modes of division, the cells can be found either adhered or swimming.
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Affiliation(s)
- Marlene Benchimol
- Universidade Santa Ursula, Rua Jornalista Orlando Dantas, 59, CEP 222-31-010 Botafogo, Rio de Janeiro, RJ, Brazil.
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Abstract
Giardia lamblia is a parasite possessing a complex cytoskeleton and an unusual morphology of bearing two nuclei. Here, the interphasic nuclei of trophozoites, using field emission scanning electron microscopy, routine scanning and transmission electron microscopy, immunocytochemistry, and 3D reconstruction, are presented. An approach using plasma-membrane extraction allowed the observation of the two nuclei still attached in their original positions. The observations are as follows: (1) Giardia nuclei and cytoskeleton were studied in demembranated cells by routine scanning electron microscopy and field emission; (2) both nuclei are anchored to basal bodies of the anterior flagella and to the descending posterior-lateral and ventral flagella, at the right and left nuclei, respectively, in cells attached by its ventral disc; (3) this attachment occurs by proteinaceous links, which were labeled by anti-actin and anti-centrin but not by anti-dynein or anti-tubulin antibodies; (4) fibrilar connections between the nuclei and the disc were also observed; and (5) nuclei exhibited a pendular movement when living cells were treated with cytochalasin, although the nuclei were still connected by their anterior region. Our analysis indicated that the nuclei have a defined position, and fibrils perform an anchoring system. This raises the possibility of a mechanism for nuclei-fidelity migration during mitosis.
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Affiliation(s)
- Marlene Benchimol
- Laboratòrio de Ultraestrutura Celular, Universidade Santa Ursula, Rua Jornalista Orlando Dantas, 59, CEP 222-31-010, Botafogo, Rio de Janeiro, Brazil.
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Benchimol M, Piva B, Campanati L, de Souza W. Visualization of the funis of Giardia lamblia by high-resolution field emission scanning electron microscopy--new insights. J Struct Biol 2005; 147:102-15. [PMID: 15193639 DOI: 10.1016/j.jsb.2004.01.017] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2003] [Revised: 12/05/2003] [Indexed: 10/26/2022]
Abstract
Giardia lamblia is a multiflagellar parasite and one of the earliest diverging eukaryotic cells. It possesses a cytoskeleton made of several microtubular structures-an adhesive disc, four pairs of flagella, median body, and funis. This protozoan displays different types of movements, including a lateral and dorso-ventral dislocation of its posterior region, which has not been completely elucidated. In the present study, high-resolution field emission scanning electron microscopy was used to analyze the funis structure of G. lamblia trophozoites. It was shown that the funis is made of short arrays of microtubules emanating from the axonemes of the caudal flagella, which are anchored to dense rods that run parallel to the posterior-lateral flagella. After emergence of the posterior-lateral flagella, funis microtubules are anchored to the epiplasm, a fibrous layer that underlies the portion of membrane that presents tail contractility. Based on these observations a model for the tail flexion of G. lamblia is proposed.
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Affiliation(s)
- Marlene Benchimol
- Universidade Santa Ursula, Laboratório de Ultraestrutura Celular--Universidade Santa Ursula, R. Jornalista Orlando Dantas, 59, Rio de Janeiro, Brazil.
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Abstract
Giardia Lamblia is a flagellar parasite possessing the unusual morphology of bearing two nuclei. New morphological observations on trophozoites and encysting Giardia nuclei using routine transmission electron microscopy, freeze fracture and cytochemistry are presented. Nuclear pores of both nuclei in the same cells were assessed on freeze-fracture replicas from different cell cycle phases, and compared. These techniques showed that (1) both nuclei in the same cell are distinct in nuclear pore number and distribution; (2) nuclear pore complexes are frequently clustered in nuclear envelope domains; (3) dividing nuclei display very few nuclear pores; (4) few ribosomes are found on the outer nuclear envelope of the trophozoite form; (5) nuclear membranes present spots of closely apposed membranes, which are different from the typical diaphragm nuclear pore complexes; (6) in addition to the nuclear pores, membrane blebs are also present in the nuclear envelope; (7) encysting cells show intranuclear inclusions, morphologically similar to the ESV (encystation-specific vesicles) and to the ER membranes, which may be the result of nuclear envelope folding. It is proposed that the two nuclei in Giardia are dissimilar in morphology and activity.
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Affiliation(s)
- Marlene Benchimol
- Universidade Santa Ursula, Rua Jornalista Orlando Dantas 59, CEP 222-31-010 Botafogo, Rio de Janeiro, Brazil.
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Carvalho KP, Monteiro-Leal LH. The caudal complex of Giardia lamblia and its relation to motility. Exp Parasitol 2005; 108:154-62. [PMID: 15582512 DOI: 10.1016/j.exppara.2004.08.007] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2004] [Revised: 08/13/2004] [Accepted: 08/17/2004] [Indexed: 11/24/2022]
Abstract
This paper presents a detailed study of the caudal complex of Giardia lamblia and its relation to movements observed in this region. The caudal complex of Giardia, composed of axonemes from the caudal flagella plus associated microtubular sheets, was investigated by light, electron microscopy, and 3D reconstruction tools. By the use of video-microscopy and digital image processing techniques, we were able to visualize in detail the caudal movements. A non-ionic detergent, Triton X-100, was used to isolate the complex that was afterwards analyzed by video-microscopy and transmission electron microscopy (TEM). We showed for the first time, using video-microscopy, that the intracellular portion of the caudal flagella axonemes presented motility, even after the disrupture of the cell membrane, contrasting with the caudal flagella themselves, that do not show active beating pattern. To check if actin filaments play a role in the above described movements, as previously supposed, we incubated the cells with jasplakinolide, a drug that induces the disruption of actin filaments in living cells. The experiments demonstrated that the drug did not affect the caudal motility. The analysis of the caudal complex by transmission electron microscopy (TEM) revealed that, even after the exposure to higher detergent concentrations, the connections between their components remained intact. The information obtained by TEM and 3D reconstruction tools showed that the region between both nuclei marks the intracellular end of the caudal complex, which proceeds toward the caudal portion of the cell following its longitudinal axis, where the axonemes emerge as the caudal flagella. The results obtained from video-microscopy assays of the isolated beating complex together with the 3D reconstruction data indicated that the internal portion of the caudal flagella is the force-generator of the movements in this region.
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Affiliation(s)
- Karina Penedo Carvalho
- Laboratório de Microscopia e Processamento de Imagens, Departemento de Histologia e Embriologia, Universidade do Estado do Rio de Janeiro, Av. Prof. Manoel de Abreu, 444-3 andar, Maracanã Rio de Janeiro, RJ 20550-170, Brazil
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Abstract
Evidence is presented for a potential involvement of the adhesive disc on the nucleus division in Giardia lamblia. The trophozoite mitotic nucleus was studied by transmission electron microscopy, freeze-fracture, freeze-substitution and also by immunofluorescence microscopy using anti-tubulin antibodies specific to spindle microtubules and Panotic staining. Prior to cell division the nucleus elongated and a displaced disc fragment, established contact with the nucleus. A progressive nucleus indentation was coincident with the concomitant presence of a disc fragment at the constricted region. One nucleus each time progressively divided until the karyokinesis was finished and two daughter-nuclei were observed. After the first karyokinesis a second karyokinesis takes place following the same procedure. When Giardia gets the four nuclei, cytokinesis occurs. Duplicated basal bodies were seen in between the first and the second karyokinesis. Immunofluorescence microscopy, using a panel of anti-tubulin antibodies, and electron microscopy of cells processed using microtubule stabilizer buffers, or cells fast-frozen and freeze-substituted, did not reveal the presence of a typical spindle. We propose that Giardia lamblia presents an uncommon mitotic behavior where the adhesive disc, a microtubular structure, seems to participate in the karyokinesis process.
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de Souza W, Lanfredi-Rangel A, Campanati L. Contribution of microscopy to a better knowledge of the biology of Giardia lamblia. Microsc Microanal 2004; 10:513-527. [PMID: 15525427 DOI: 10.1017/s1431927604040954] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2002] [Indexed: 05/24/2023]
Abstract
Giardia lamblia is a flagellated protozoan of great medical and biological importance. It is the causative agent of giardiasis, one of the most prevalent diarrheal disease both in developed and third-world countries. Morphological studies have shown that G. lamblia does not present structures such as peroxisomes, mitochondria, and a well-elaborated Golgi complex. In this review, special emphasis is given to the contribution made by various microscopic techniques to a better knowledge of the biology of the protozoan. The application of video microscopy, immunofluorescence confocal laser scanning microscopy, and several techniques associated with transmission electron microscopy (thin section, enzyme cytochemistry, freeze-fracture, deep-etching, fracture-flip) to the study of the cell surface, peripheral vesicles, endoplasmic reticulum-Golgi complex system, and of the encystation vesicles found in trophozoites and during the process of trophozoite-cyst transformation are discussed.
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Affiliation(s)
- Wanderley de Souza
- Laboratório de Ultraestrutura Celular, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, CCS-Bloco G, 21949-900, Rio de Janeiro-RJ, Brazil.
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Benchimol M. The release of secretory vesicle in encysting Giardia lamblia. FEMS Microbiol Lett 2004; 235:81-7. [PMID: 15158265 DOI: 10.1016/j.femsle.2004.04.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2004] [Revised: 04/06/2004] [Accepted: 04/07/2004] [Indexed: 09/30/2022] Open
Abstract
Giardia is an intestinal parasite that undergoes adaptation for survival outside the host. It secretes an extracellular cyst wall using a poorly understood process. An encystation-specific secretory vesicle (ESV) was previously described containing cyst wall proteins. The process of release of these vesicles has been suggested to occur after fragmentation of large ESV in small secretory vesicles, followed by exocytosis, but it was not demonstrated. The release of the ESV was studied by transmission electron microscopy. It was observed: (1) the moment of vesicle release; (2) that a large vesicle is exocytosed and does not fragment into small vesicles; (3) membrane fusion is distinct from traditional exocytosis since it is incomplete; (4) the occurrence of membrane fragmentation and that those membranes reseal to form ghosts; (5) these membrane ghosts may be endocytosed, adhered to flagellar surface or/and form empty vesicles in the extracellular medium.
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Affiliation(s)
- Marlene Benchimol
- Laboratório de Ultraestrutura Celular, Universidade Santa Ursula, Rua Journalistan Orlando Dantas 59, 223 31-010 Botafago, Rio de Janeiro, RJ, Brazil.
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Corrêa G, Morgado-Diaz JA, Benchimol M. Centrin in Giardia lamblia - ultrastructural localization. FEMS Microbiol Lett 2004; 233:91-6. [PMID: 15043874 DOI: 10.1016/j.femsle.2004.01.043] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2003] [Revised: 11/12/2003] [Accepted: 01/26/2004] [Indexed: 10/26/2022] Open
Abstract
Giardia lamblia is a multiflagellar parasite and one of the earliest diverging eukaryotic cells. It possesses a complex cytoskeleton based on different groups of microtubular structures - a ventral adhesive disc, four pairs of flagella, a median body and funis. Centrin is an important member of the EF-hand family of calcium-binding proteins, and it is known to show calcium-sensitive contractile behaviour. In the present study, we performed an ultrastructural localization of centrin in G. lamblia using several monoclonal antibodies to centrin. Microtubular structures such as the basal bodies, all the flagella axonemes, the adhesive disc, funis, and the median bodies presented positive labelling to centrin. In addition, the dense rods also demonstrated positive labelling. These results show that centrin is located in key positions related to microtubules. The role of centrin in these dynamic regions is discussed.
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Affiliation(s)
- Gladys Corrêa
- Laboratório de Ultraestrutura Celular, Universidade Santa Ursula, Rua Jornalista Orlando Dantas, 59 Botafogo, CEP 22231-010, Rio de Janeiro, Brazil
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