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Vengesai A, Muleya V, Midzi H, Tinago TV, Chipako I, Manuwa M, Naicker T, Mduluza T. Diagnostic performances of Schistosoma haematobium and Schistosoma mansoni recombinant proteins, peptides and chimeric proteins antibody based tests. Systematic scoping review. PLoS One 2023; 18:e0282233. [PMID: 36862712 PMCID: PMC9980832 DOI: 10.1371/journal.pone.0282233] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Accepted: 02/11/2023] [Indexed: 03/03/2023] Open
Abstract
BACKGROUND Traditional diagnostic tests for schistosome infections are suboptimal, particularly when the parasite burden is low. In the present review we sought to identify recombinant proteins, peptides, and chimeric proteins with potential to be used as sensitive and specific diagnostic tools for schistosomiasis. METHODS The review was guided by PRISMA-ScR guidelines, Arksey and O'Malley's framework, and guidelines from the Joanna Briggs Institute. Five databases were searched: Cochrane library, PubMed, EMBASE, PsycInfo and CINAHL, alongside preprints. Identified literature were assessed by two reviewers for inclusion. A narrative summary was used to interpret the tabulated results. RESULTS Diagnostic performances were reported as specificities, sensitivities, and AUC. The AUC for S. haematobium recombinant antigens ranged from 0.65 to 0.98, and 0.69 to 0.96 for urine IgG ELISA. S. mansoni recombinant antigens had sensitivities ranging from 65.3% to 100% and specificities ranging from 57.4% to 100%. Except for 4 peptides which had poor diagnostic performances, most peptides had sensitivities ranging from 67.71% to 96.15% and specificities ranging from 69.23% to 100%. S. mansoni chimeric protein was reported to have a sensitivity of 86.8% and a specificity of 94.2%. CONCLUSION The tetraspanin CD63 antigen had the best diagnostic performance for S. haematobium. The tetraspanin CD63 antigen Serum IgG POC-ICTs had a sensitivity of 89% and a specificity of 100%. Peptide Smp_150390.1 (216-230) serum based IgG ELISA had the best diagnostic performance for S. mansoni with a sensitivity of 96.15% and a specificity of 100%. Peptides were reported to demonstrate good to excellent diagnostic performances. S. mansoni multi-peptide chimeric protein further improved the diagnostic accuracy of synthetic peptides. Together with the advantages associated with urine sampling technique, we recommend development of multi-peptide chimeric proteins urine based point of care tools.
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Affiliation(s)
- Arthur Vengesai
- Department of Biochemistry, Faculty of Medicine and Health Sciences, Midlands State University, Gweru, Zimbabwe
- * E-mail:
| | - Victor Muleya
- Department of Biochemistry, Faculty of Medicine and Health Sciences, Midlands State University, Gweru, Zimbabwe
| | - Herald Midzi
- Department of Biochemistry, University of Zimbabwe, Mt Pleasant, Harare, Zimbabwe
| | | | - Isaac Chipako
- Aravas Pharmaceuticals Pvt LTD, Prospect Industrial Area, Harare, Zimbabwe
| | - Marble Manuwa
- Department of Biochemistry, University of Zimbabwe, Mt Pleasant, Harare, Zimbabwe
| | - Thajasvarie Naicker
- Discipline of Optics and Imaging, Doris Duke Medical Research Institute, College of Health Sciences, University of KwaZulu-Natal, Durban, South Africa
| | - Takafira Mduluza
- Department of Biochemistry, University of Zimbabwe, Mt Pleasant, Harare, Zimbabwe
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Jimenez V, Mesones S. Down the membrane hole: Ion channels in protozoan parasites. PLoS Pathog 2022; 18:e1011004. [PMID: 36580479 DOI: 10.1371/journal.ppat.1011004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Parasitic diseases caused by protozoans are highly prevalent around the world, disproportionally affecting developing countries, where coinfection with other microorganisms is common. Control and treatment of parasitic infections are constrained by the lack of specific and effective drugs, plus the rapid emergence of resistance. Ion channels are main drug targets for numerous diseases, but their potential against protozoan parasites is still untapped. Ion channels are membrane proteins expressed in all types of cells, allowing for the flow of ions between compartments, and regulating cellular functions such as membrane potential, excitability, volume, signaling, and death. Channels and transporters reside at the interface between parasites and their hosts, controlling nutrient uptake, viability, replication, and infectivity. To understand how ion channels control protozoan parasites fate and to evaluate their suitability for therapeutics, we must deepen our knowledge of their structure, function, and modulation. However, methodological approaches commonly used in mammalian cells have proven difficult to apply in protozoans. This review focuses on ion channels described in protozoan parasites of clinical relevance, mainly apicomplexans and trypanosomatids, highlighting proteins for which molecular and functional evidence has been correlated with their physiological functions.
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Abstract
Entamoeba histolytica is a protozoan parasite responsible for amoebiasis, a disease with a high prevalence in developing countries. Establishing an amoebic infection involves interplay between pathogenic factors for invasion and tissue damage, and immune responses for protecting the host. Here, we review the pathogenicity of E. histolytica and summarize the latest knowledge on immune response and immune evasion mechanisms during amoebiasis.
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Affiliation(s)
- Eileen Uribe-Querol
- División de Estudios de Posgrado e Investigación, Facultad de Odontología, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Carlos Rosales
- Departamento de Inmunología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Mexico City, Mexico
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Rosales C. Neutrophils vs. amoebas: Immunity against the protozoan parasite Entamoeba histolytica. J Leukoc Biol 2021; 110:1241-1252. [PMID: 34085314 DOI: 10.1002/jlb.4mr0521-849rr] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 05/08/2021] [Accepted: 05/10/2021] [Indexed: 12/29/2022] Open
Abstract
Entamoeba histolytica is a protozoan parasite with high prevalence in developing countries, and causes amoebiasis. This disease affects the intestine and the liver, and is the third leading cause of human deaths among parasite infections. E. histolytica infection of the intestine or liver is associated with a strong inflammation characterized by a large number of infiltrating neutrophils. Consequently, several reports suggest that neutrophils play a protective role in amoebiasis. However, other reports indicate that amoebas making direct contact with neutrophils provoke lysis of these leukocytes, resulting in the release of their lytic enzymes, which in turn provoke tissue damage. Therefore, the role of neutrophils in this parasitic infection remains controversial. Neutrophils migrate from the circulation to sites of infection, where they display several antimicrobial functions, including phagocytosis, degranulation, and formation of neutrophil extracellular traps (NET). Recently, it was found that E. histolytica trophozoites are capable of inducing NET formation. Neutrophils in touch with amoebas launched NET in an explosive manner around the amoebas and completely covered them in nebulous DNA and cell aggregates where parasites got immobilized and killed. In addition, the phenotype of neutrophils can be modified by the microbiome resulting in protection against amoebas. This review describes the mechanisms of E. histolytica infection and discusses the novel view of how neutrophils are involved in innate immunity defense against amoebiasis. Also, the mechanisms on how the microbiome modulates neutrophil function are described.
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Affiliation(s)
- Carlos Rosales
- Departamento de Inmunología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Mexico City, Mexico
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5
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König C, Honecker B, Wilson IW, Weedall GD, Hall N, Roeder T, Metwally NG, Bruchhaus I. Taxon-Specific Proteins of the Pathogenic Entamoeba Species E. histolytica and E. nuttalli. Front Cell Infect Microbiol 2021; 11:641472. [PMID: 33816346 PMCID: PMC8017271 DOI: 10.3389/fcimb.2021.641472] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Accepted: 03/03/2021] [Indexed: 01/30/2023] Open
Abstract
The human protozoan parasite Entamoeba histolytica can live in the human intestine for months or years without generating any symptoms in the host. For unknown reasons, amoebae can suddenly destroy the intestinal mucosa and become invasive. This can lead to amoebic colitis or extraintestinal amoebiasis whereby the amoebae spread to other organs via the blood vessels, most commonly the liver where abscesses develop. Entamoeba nuttalli is the closest genetic relative of E. histolytica and is found in wild macaques. Another close relative is E. dispar, which asyptomatically infects the human intestine. Although all three species are closely related, only E. histolytica and E. nuttalli are able to penetrate their host’s intestinal epithelium. Lineage-specific genes and gene families may hold the key to understanding differences in virulence among species. Here we discuss those genes found in E. histolytica that have relatives in only one or neither of its sister species, with particular focus on the peptidase, AIG, Ariel, and BspA families.
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Affiliation(s)
- Constantin König
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Barbara Honecker
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Ian W Wilson
- Institute of Infection, Veterinary & Ecological Sciences, University of Liverpool, Liverpool, United Kingdom
| | - Gareth D Weedall
- School of Biological and Environmental Sciences, Liverpool John Moores University, Liverpool, United Kingdom
| | - Neil Hall
- Earlham Institute, Norwich, United Kingdom.,School of Biological Sciences, University of East Anglia, Norwich, United Kingdom
| | - Thomas Roeder
- Zoology, Department of Molecular Physiology, Kiel University, Kiel, Germany.,Airway Research Center North (ARCN), German Center for Lung Research (DZL), Kiel, Germany
| | | | - Iris Bruchhaus
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany.,Department of Biology, University of Hamburg, Hamburg, Germany
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Kim WH, Lillehoj HS. Immunity, immunomodulation, and antibiotic alternatives to maximize the genetic potential of poultry for growth and disease response. Anim Feed Sci Technol 2019. [DOI: 10.1016/j.anifeedsci.2018.09.016] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Hirt RP, de Miguel N, Nakjang S, Dessi D, Liu YC, Diaz N, Rappelli P, Acosta-Serrano A, Fiori PL, Mottram JC. Trichomonas vaginalis pathobiology new insights from the genome sequence. Adv Parasitol 2012; 77:87-140. [PMID: 22137583 DOI: 10.1016/b978-0-12-391429-3.00006-x] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The draft genome of the common sexually transmitted pathogen Trichomonas vaginalis encodes one of the largest known proteome with 60,000 candidate proteins. This provides parasitologists and molecular cell biologists alike with exciting, yet challenging, opportunities to unravel the molecular features of the parasite's cellular systems and potentially the molecular basis of its pathobiology. Here, recent investigations addressing selected aspects of the parasite's molecular cell biology are discussed, including surface and secreted virulent factors, membrane trafficking, cell signalling, the degradome, and the potential role of RNA interference in the regulation of gene expression.
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Affiliation(s)
- Robert P Hirt
- Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, UK
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8
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Christy NCV, Petri WA. Mechanisms of adherence, cytotoxicity and phagocytosis modulate the pathogenesis of Entamoeba histolytica. Future Microbiol 2011; 6:1501-19. [DOI: 10.2217/fmb.11.120] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The unicellular parasite Entamoeba histolytica, the causative agent of the human disease amebiasis, has traditionally been distinguished from its nonpathogenic cousin Entamoeba dispar by its propensity for the ingestion of erythrocytes. This classic feature, along with the parasite’s ability to cause extensive host cell death, are critical mechanisms of pathogenesis during human infection. Recent advances have led to a greater understanding of the molecular components that allow E. histolytica to kill and phagocytose extracellular targets during human infection and include detailed studies of the role of the parasite’s cysteine proteinases and other effectors of cytotoxicity, as well as the mechanisms of ligand recognition, signaling and intracellular trafficking during phagocytosis.
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Affiliation(s)
- Nathaniel CV Christy
- Department of Microbiology, University of Virginia, Charlottesville, Virginia, 22908, USA
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Abstract
Entamoeba histolytica is the causative agent of amoebiasis in humans and is responsible for an estimated 100 000 deaths annually, making it the second leading cause of death due to a protozoan parasite after Plasmodium. Pathogenesis appears to result from the potent cytotoxic activity of the parasite, which kills host cells within minutes. The mechanism is unknown, but progress has been made in determining that cytotoxicity requires parasite Gal (galactose)/GalNAc (N-acetylgalactosamine) lectin-mediated adherence, target cell calcium influx, dephosphorylation and activation of caspase 3. Putative cytotoxic effector proteins such as amoebapores, proteases and various parasite membrane proteins have also been identified. Nonetheless the bona fide cytotoxic effector molecules remain unknown and it is unclear how the lethal hit is delivered. To better understand the basic mechanism of pathogenesis and to enable the development of new therapeutics, more work will be needed in order to determine how the parasite elicits host cell death.
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Willis C, Wang CK, Osman A, Simon A, Pickering D, Mulvenna J, Riboldi-Tunicliffe A, Jones MK, Loukas A, Hofmann A. Insights into the membrane interactions of the saposin-like proteins Na-SLP-1 and Ac-SLP-1 from human and dog hookworm. PLoS One 2011; 6:e25369. [PMID: 21991310 DOI: 10.1371/journal.pone.0025369] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2011] [Accepted: 09/01/2011] [Indexed: 12/03/2022] Open
Abstract
Saposin-like proteins (SAPLIPs) from soil-transmitted helminths play pivotal roles in host-pathogen interactions and have a high potential as targets for vaccination against parasitic diseases. We have identified two non-orthologous SAPLIPs from human and dog hookworm, Na-SLP-1 and Ac-SLP-1, and solved their three-dimensional crystal structures. Both proteins share the property of membrane binding as monitored by liposome co-pelleting assays and monolayer adsorption. Neither SAPLIP displayed any significant haemolytic or bactericidal activity. Based on the structural information, as well as the results from monolayer adsorption, we propose models of membrane interactions for both SAPLIPs. Initial membrane contact of the monomeric Na-SLP-1 is most likely by electrostatic interactions between the membrane surface and a prominent basic surface patch. In case of the dimeric Ac-SLP-1, membrane interactions are most likely initiated by a unique tryptophan residue that has previously been implicated in membrane interactions in other SAPLIPs.
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Abstract
Entamoeba histolytica is the causative agent of amebiasis, a disease that is a major source of morbidity and mortality in the developing world. The potent cytotoxic activity of the parasite appears to underlie disease pathogenesis, although the mechanism is unknown. Recently, progress has been made in determining that the parasite activates apoptosis in target cells and some putative effectors have been identified. Recent studies have also begun to unravel the host genetic determinants that influence infection outcome. Thus, we are beginning to get a clearer picture of how this parasite manages to infect, invade and ultimately inflict devastating tissue destruction.
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Affiliation(s)
- Katherine S Ralston
- Department of Medicine, University of Virginia Health Sciences Center, Charlottesville, VA, USA
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12
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Bracha R, Nuchamowitz Y, Wender N, Mirelman D. Transcriptional gene silencing reveals two distinct groups of Entamoeba histolytica Gal/GalNAc-lectin light subunits. Eukaryot Cell 2007; 6:1758-65. [PMID: 17766462 PMCID: PMC2043392 DOI: 10.1128/ec.00241-07] [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] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The Entamoeba histolytica cell surface Gal/GalNAc-inhibitable lectin is a heterodimer between a heavy (170 kDa) subunit linked via a disulfide bond to a light (31 to 35 kDa) subunit. Five light subunit genes with high homology have been identified (Ehlgl1 to -5). We have previously shown that silencing of the expression of Ehlgl1, in the G3 trophozoites which had already been silenced in the amoebapore gene (Ehap-a), also suppressed the transcription of Ehlgl2 and -3 (strain RBV). The total absence of the lgl1 to -3 subunits in the RBV trophozoites affected their ability to cap the surface Gal-lectin molecules to the uroid region. We have now found that in the RBV trophozoites, the lgl4 and -5 subunits (31 kDa) are overexpressed and appear to compensate for the missing lgl1 to -3 in the heterodimer complex. Transcriptional silencing of Ehlgl5 was achieved by transfection of G3 trophozoites with a plasmid containing the open reading frame of Ehlgl5 ligated to the 5' promoter region of the Ehap-a gene. The transfected trophozoites (strain L5) were silenced in Ehlgl5 and the closely related Ehlgl4, while the expression of the larger lgl1 to -3 subunits was upregulated. L5 trophozoites retained their ability to cap the Gal-lectin molecules. Attempts to simultaneously silence all of the Ehlgl genes have failed so far, possibly due to their crucial importance to the Gal-lectin functions. Our ability to silence part of the genes belonging to the same family can serve as a tool to study the relationships and functions of the members of other gene families.
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Affiliation(s)
- Rivka Bracha
- Weizmann Institute of Science, Department of Biological Chemistry, Rehovot, Israel
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13
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Abstract
Entamoeba histolytica is a protozoan parasite of humans that causes 40,000-100,000 deaths annually. Clinical amoebiasis results from the spread of the normally luminal parasite into the colon wall and beyond; the key development in understanding this complex multistage process has been the publication of the E. histolytica genome, from which has come an explosion in the use of microarrays to examine changes in gene expression that result from changes in growth conditions. The genome has also revealed a unique arrangement of tRNA genes and an extraordinary number of genes for putative virulence factors, many unexpressed under the artificial conditions of growth in culture. The ability to induce apoptosis of mammalian cells and a useful, but as yet little-understood, technique for epigenetic irreversible gene silencing are other exciting developments.
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Affiliation(s)
- John P Ackers
- Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
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Bracha R, Nuchamowitz Y, Anbar M, Mirelman D. Transcriptional silencing of multiple genes in trophozoites of Entamoeba histolytica. PLoS Pathog 2006; 2:e48. [PMID: 16733544 PMCID: PMC1464398 DOI: 10.1371/journal.ppat.0020048] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.3] [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: 12/29/2005] [Accepted: 04/10/2006] [Indexed: 01/19/2023] Open
Abstract
In a previous work we described the transcriptional silencing of the amoebapore A (AP-A) gene (Ehap-a) of Entamoeba histolytica strain HM-1:IMSS. The silencing occurred following transfection with a plasmid containing a 5′ upstream region (473 bp) of Ehap-a that included a truncated segment (140 bp) of a short interspersed nuclear element (SINE1). Silencing remained in effect even after removal of the plasmid (clone G3). Neither short interfering RNA nor methylated DNA were detected, but the chromatin domain of Ehap-a in the gene-silenced trophozoites was modified. Two other similar genes (Ehap-b and one encoding a Saposin-like protein, SAPLIP 1) also became silenced. In the present work we demonstrate the silencing of a second gene of choice, one that encodes the light subunit of the Gal/GalNAc inhibitable lectin (Ehlgl1) and the other, the cysteine proteinase 5 (EhCP-5). This silencing occurred in G3 trophozoites transfected with a plasmid in which the 473 bp 5′ upstream Ehap-a fragment was directly ligated to the second gene. Transcriptional silencing occurred in both the transgene and the chromosomal gene. SINE1 sequences were essential, as was a direct connection between the Ehap-a upstream region and the beginning of the open reading frame of the second gene. Gene silencing did not occur in strain HM-1:IMSS with any of these plasmid constructs. The trophozoites with two silenced genes were virulence-attenuated as were those of clone G3. In addition, trophozoites not expressing Lgl1 and AP-A proteins had a significantly reduced ability to cap the Gal/GalNAc-lectin to the uroid region when incubated with antibodies against the heavy (170 kDa) subunit of the lectin. Lysates of trophozoites lacking cysteine proteinase 5 and AP-A proteins had 30% less cysteine proteinase activity than those of HM-1:IMSS strain or the G3 clone. Silencing of other genes in G3 amoebae could provide a model to study their various functions. In addition, double gene-silenced, virulence-attenuated trophozoites may be an important tool in vaccine development. The human intestinal parasite Entamoeba histolytica has numerous genes that code for virulence. Silencing the expression of individual genes is useful to determine their roles. In previous work the authors demonstrated the silencing of the gene coding for amoebapore, which is responsible for killing of human cells. They transfected amoebic trophozoites with a plasmid that contained DNA sequences homologous to the promoter region of the amoebapore gene, as well as a portion of a repetitive DNA element (called a short interspersed nuclear element). This construct induced a modification of the chromatin and prevented the expression of the gene. Removal of the plasmid resulted in stable, amoebapore-deficient parasites possessing low virulence. In the present work, Bracha and colleagues show silencing of additional genes following transfection of E. histolytica trophozoites already silenced in amoebapore with a plasmid containing the second gene directly ligated to the upstream region of the amoebapore gene. The DNA sequences that are essential for transferring the silencing from the plasmid to the chromosomal gene copy were identified. Additional virulence genes that the authors irreversibly silenced are those encoding a subunit of a surface lectin that mediates the adherence of the parasite to host cells, and a cysteine proteinase that plays a role in inflammation and invasion of the intestine.
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Affiliation(s)
- Rivka Bracha
- Department of Biological Chemistry, Weizmann Institute of Science, Rehovot, Israel
| | - Yael Nuchamowitz
- Department of Biological Chemistry, Weizmann Institute of Science, Rehovot, Israel
| | - Michael Anbar
- Department of Biological Chemistry, Weizmann Institute of Science, Rehovot, Israel
| | - David Mirelman
- Department of Biological Chemistry, Weizmann Institute of Science, Rehovot, Israel
- * To whom correspondence should be addressed. E-mail:
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Winkelmann J, Leippe M, Bruhn H. A novel saposin-like protein of Entamoeba histolytica with membrane-fusogenic activity. Mol Biochem Parasitol 2006; 147:85-94. [PMID: 16529828 DOI: 10.1016/j.molbiopara.2006.01.010] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2005] [Revised: 01/20/2006] [Accepted: 01/24/2006] [Indexed: 02/04/2023]
Abstract
Amoebapores, the pore-forming proteins of Entamoeba histolytica, are major pathogenicity factors of the parasite. Upon a comprehensive survey in the recently completed genome data sets for the protozoon, we identified in addition to the three amoebapore genes, 16 genes which are constitutively expressed and code for structurally similar proteins, all belonging to the family of saposin-like proteins. Here, we recombinantly expressed in bacteria a defined single entity of this expansive amoebic protein family, namely SAPLIP 3. The protein consists of the saposin-like domain only, comparable to amoebapores, and we characterized its interactions with membranes using different assays. In contrast to amoebapores, SAPLIP 3 neither forms pores in liposomes nor permeabilizes bacterial membranes. However, SAPLIP 3 induces leaky fusion of lipid vesicles as evidenced by fluorescence microscopic analysis and by using a fusion assay that monitors the dequenching of a lipophilic dye. The membrane-fusogenic activity of SAPLIP 3 which is dependent on the presence of negatively charged lipids and on acidic pH resembles in combination with the negative surface charge of the protein characteristics of human saposin C. Beside its function as a cofactor of sphingolipid hydrolysing enzymes, the human protein is considered to be involved in the reorganization of lysosomal compartments due to its fusogenic activity. We hypothesize that in the amoeba, SAPLIP 3 fulfils a similar function in the multifarious endo- and exocytotic transport processes.
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Affiliation(s)
- Julia Winkelmann
- Research Center for Infectious Diseases, University of Wuerzburg, Roentgenring 11, D-97070 Wuerzburg, Germany
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Abstract
SAPLIPs (saposin-like proteins) are a diverse family of lipid-interacting proteins that have various and only partly understood, but nevertheless essential, cellular functions. Their existence is conserved in phylogenetically most distant organisms, such as primitive protozoa and mammals. Owing to their remarkable sequence variability, a common mechanism for their actions is not known. Some shared principles beyond their diversity have become evident by analysis of known three-dimensional structures. Whereas lipid interaction is the basis for their functions, the special cellular tasks are often defined by interaction partners other than lipids. Based on recent findings, this review summarizes phylogenetic relations, function and structural features of the members of this family.
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Affiliation(s)
- Heike Bruhn
- Research Center for Infectious Diseases, Röntgenring 11, D-97070 Würzburg, Germany.
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Aksoy U, Ustun S, Dagci H, Yazar S. Effects of Cd +2, Cu +2, Ba +2 and Co +2 ions on Entamoeba histolytica cysts. World J Gastroenterol 2004; 10:449-51. [PMID: 14760778 PMCID: PMC4724924 DOI: 10.3748/wjg.v10.i3.449] [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] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
AIM: The effects of cobalt, copper, cadmium and barium ions on the cysts of Entamoeba histolytica (E. histolytica), an amebic dysentery agent, cultured in Robinson medium were investigated.
METHODS: E. histolytica cysts and trophozoites isolated from a patient with amebiasis were cultivated in the medium, incubated at 37 °C for a period of 4 days and 40 × 104/ml amebic cysts were then transferred to a fresh medium. At the second stage, 0.05, 0.1 and 0.2 mM of selected metal ions were added to the medium, and the effects of these ions on parasitic reproduction compared with the control group were observed.
RESULTS: It was determined that the number of living parasites in all the groups containing metal ions decreased significantly starting from 30 minutes (P < 0.01). CuCl2 showed the highest lethal effect on E. histolytica cysts, whereas the lowest lethal effect was observed with CoCl2. It was also seen that the number of living cells was decreased as the ion concentration and exposure time were increased, and that there were no living parasites in the medium at the end of 24 h (P < 0.01).
CONCLUSION: It may be stated that the effect of ever-increasing contamination of the environment with metal waste materials on parasites should be investigated further.
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Affiliation(s)
- Umit Aksoy
- Department of Parasitology, Medical Faculty, Dokuz Eylül University, Znciralti, Zzmir, Turkey
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Abstract
Entamoeba invadens, a parasite of reptiles, is a model for the study of encystation by the human enteric pathogen Entamoeba histolytica, because E. invadens form cysts in axenic culture. With approximately 0.5-fold sequence coverage of the genome, we were able to get insights into E. invadens gene and genome features. Overall, the E. invadens genome displays many of the features that are emerging from ongoing genome sequencing efforts in E. histolytica. At the nucleotide level the E. invadens genome has on average 60% sequence identity with that of E. histolytica. The presence of introns in E. invadens was predicted with similar consensus (GTTTGT em leader A/TAG) sequences to those identified in E. histolytica and Entamoeba dispar. Sequences highly repeated in the genome of E. histolytica (rRNAs, tRNAs, CXXC-rich proteins, and Leu-rich repeat proteins) were found to be highly repeated in the E. invadens genome. Numerous proteins homologous to those implicated in amoebic virulence, (Gal/GalNAc lectins, amoebapores, and cysteine proteinases) and drug resistance (p-glycoproteins) were identified. Homologs of proteins involved in cell cycle, vesicular trafficking and signal transduction were identified, which may be involved in en/excystation and cell growth of E. invadens. Finally, multiple copies of a number of E. invadens genes coding for predicted enzymes involved in core metabolism and the targets of anti-amoebic drugs were identified.
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Affiliation(s)
- Zheng Wang
- Center for Bio/Molecular Science Naval Research Laboratory, Washington, DC 20375, USA
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Abstract
It is an exciting time in the study of Entamoeba histolytica. Over the past two years, the natural history and burden of disease in humans has been redefined, mucosal immune responses associated with protection identified, and the developmental regulation of encystation outlined. The number of genes sequenced has increased from a few hundred to a few thousand, and study of the genome structure is revealing unusual repetitive elements and plasticity. DNA microarrays promise the first ability to examine global patterns of mRNA abundance. The mechanism of transcriptional control via histone modifications and sequence-specific DNA-binding proteins are to be delineated. Advances in cell biology are providing new insights into invasion through the intestinal epithelium.
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Affiliation(s)
- William A Petri
- Division of Infectious Diseases, Room 2115, MR4 Building, Lane Road, PO Box 801340, University of Virginia Health System, Charlottesville, Virginia 22908-1340, USA.
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