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Differential detection of Entamoeba histolytica, Entamoeba dispar and Entamoeba moshkovskii in faecal samples using nested multiplex PCR in west of Iran. Epidemiol Infect 2020; 147:e96. [PMID: 30869025 PMCID: PMC6519685 DOI: 10.1017/s0950268819000141] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
This study aimed to determine the prevalence of Entamoeba histolytica, Entamoeba dispar and Entamoeba moshkovskii (collectively referred to as Entamoeba complex), using microscopic and molecular methods in Kurdistan Province, northwest of Iran. The relationship between positive Entamoeba species and clinical symptoms was also investigated. Eight positive Entamoeba complex, as well as four Entamoeba complex-like isolates, were detected by microscopic stool examination. DNA was extracted from all positive and from 55 randomly selected negative stool samples. PCR was performed using species-specific 18S rRNA primers for the Entamoeba complex. All positive PCR samples were sequenced. In total, 14 (1.01%) out of 1383 isolates, i.e. 12 microscopy-positive and Entamoeba complex-like isolates and two out of 55 microscopy-negative isolates, were identified via PCR and sequencing. Overall, 0.58% (8/1383) of the isolates were E. dispar, 0.14% (2/1383) E. histolytica, 0.07% (1/1383) E. moshkovskii and 0.22% (3/1383) were mixed of E. histolytica and E. dispar. Based on our findings, the prevalence of E. dispar is greater than that of E. histoltyica. On the other hand, a case of E. moshkovskii was reported for the first time in this region. It seems that some gastrointestinal symptoms may be attributed to Entamoeba species.
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Abstract
The protozoan parasite Entamoeba histolytica is the microbial agent of amoebiasis - an infection that is endemic worldwide and is associated with high morbidity and mortality rates. As the disease develops, virulent E. histolytica deplete the mucus layer, interact with the intestinal epithelium, and then degrade the colonic mucosa and disrupt the extracellular matrix (ECM). Our research demonstrated that virulent parasites with an invasive phenotype display rapid, highly specific changes in their transcriptome (notably for essential factors involved in carbohydrate metabolism and the processing of glycosylated residues). Moreover, combined activation of parasite and host lytic enzymes leads to the destruction of the intestinal parenchyma. Together, these enzymes degrade the mucus layer and the ECM, and trigger the inflammatory response essential to the development of amoebiasis.
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Knockdown of Five Genes Encoding Uncharacterized Proteins Inhibits Entamoeba histolytica Phagocytosis of Dead Host Cells. Infect Immun 2016; 84:1045-1053. [PMID: 26810036 DOI: 10.1128/iai.01325-15] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2015] [Accepted: 01/15/2016] [Indexed: 12/17/2022] Open
Abstract
Entamoeba histolytica is the protozoan parasite that causes invasive amebiasis, which is endemic to many developing countries and characterized by dysentery and liver abscesses. The virulence of E. histolytica correlates with the degree of host cell engulfment, or phagocytosis, and E. histolytica phagocytosis alters amebic gene expression in a feed-forward manner that results in an increased phagocytic ability. Here, we used a streamlined RNA interference screen to silence the expression of 15 genes whose expression was upregulated in phagocytic E. histolytica trophozoites to determine whether these genes actually function in the phagocytic process. When five of these genes were silenced, amebic strains with significant decreases in the ability to phagocytose apoptotic host cells were produced. Phagocytosis of live host cells, however, was largely unchanged, and the defects were surprisingly specific for phagocytosis. Two of the five encoded proteins, which we named E. histolytica ILWEQ (EhILWEQ) and E. histolytica BAR (EhBAR), were chosen for localization via SNAP tag labeling and localized to the site of partially formed phagosomes. Therefore, both EhILWEQ and EhBAR appear to contribute to E. histolytica virulence through their function in phagocytosis, and the large proportion (5/15 [33%]) of gene-silenced strains with a reduced ability to phagocytose host cells validates the previously published microarray data set demonstrating feed-forward control of E. histolytica phagocytosis. Finally, although only limited conclusions can be drawn from studies using the virulence-deficient G3 Entamoeba strain, the relative specificity of the defects induced for phagocytosis of apoptotic cells but not healthy cells suggests that cell killing may play a rate-limiting role in the process of Entamoeba histolytica host cell engulfment.
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Thibeaux R, Weber C, Hon CC, Dillies MA, Avé P, Coppée JY, Labruyère E, Guillén N. Identification of the virulence landscape essential for Entamoeba histolytica invasion of the human colon. PLoS Pathog 2013; 9:e1003824. [PMID: 24385905 PMCID: PMC3868522 DOI: 10.1371/journal.ppat.1003824] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2013] [Accepted: 10/25/2013] [Indexed: 02/02/2023] Open
Abstract
Entamoeba histolytica is the pathogenic amoeba responsible for amoebiasis, an infectious disease targeting human tissues. Amoebiasis arises when virulent trophozoites start to destroy the muco-epithelial barrier by first crossing the mucus, then killing host cells, triggering inflammation and subsequently causing dysentery. The main goal of this study was to analyse pathophysiology and gene expression changes related to virulent (i.e. HM1:IMSS) and non-virulent (i.e. Rahman) strains when they are in contact with the human colon. Transcriptome comparisons between the two strains, both in culture conditions and upon contact with human colon explants, provide a global view of gene expression changes that might contribute to the observed phenotypic differences. The most remarkable feature of the virulent phenotype resides in the up-regulation of genes implicated in carbohydrate metabolism and processing of glycosylated residues. Consequently, inhibition of gene expression by RNA interference of a glycoside hydrolase (β-amylase absent from humans) abolishes mucus depletion and tissue invasion by HM1:IMSS. In summary, our data suggest a potential role of carbohydrate metabolism in colon invasion by virulent E. histolytica.
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Affiliation(s)
- Roman Thibeaux
- Institut Pasteur, Unité Biologie Cellulaire du Parasitisme, Paris, France
- INSERM U786, Paris, France
- Université de Versailles Saint-Quentin-en-Yvelines, Versailles, France
| | - Christian Weber
- Institut Pasteur, Unité Biologie Cellulaire du Parasitisme, Paris, France
- INSERM U786, Paris, France
| | - Chung-Chau Hon
- Institut Pasteur, Unité Biologie Cellulaire du Parasitisme, Paris, France
- INSERM U786, Paris, France
| | - Marie-Agnès Dillies
- Institut Pasteur, Transcriptome et Epigénome, Département Génomes et Génétique, Paris, France
| | - Patrick Avé
- Institut Pasteur, Unité Histopathologie Humaine et Modèles Animaux, Paris, France
| | - Jean-Yves Coppée
- Institut Pasteur, Transcriptome et Epigénome, Département Génomes et Génétique, Paris, France
| | - Elisabeth Labruyère
- Institut Pasteur, Unité Biologie Cellulaire du Parasitisme, Paris, France
- INSERM U786, Paris, France
- * E-mail: (EL); (NG)
| | - Nancy Guillén
- Institut Pasteur, Unité Biologie Cellulaire du Parasitisme, Paris, France
- INSERM U786, Paris, France
- * E-mail: (EL); (NG)
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Kumari V, Iyer LR, Roy R, Bhargava V, Panda S, Paul J, Verweij JJ, Clark CG, Bhattacharya A, Bhattacharya S. Genomic distribution of SINEs in Entamoeba histolytica strains: implication for genotyping. BMC Genomics 2013; 14:432. [PMID: 23815468 PMCID: PMC3716655 DOI: 10.1186/1471-2164-14-432] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2012] [Accepted: 06/20/2013] [Indexed: 11/01/2022] Open
Abstract
BACKGROUND The major clinical manifestations of Entamoeba histolytica infection include amebic colitis and liver abscess. However the majority of infections remain asymptomatic. Earlier reports have shown that some E. histolytica isolates are more virulent than others, suggesting that virulence may be linked to genotype. Here we have looked at the genomic distribution of the retrotransposable short interspersed nuclear elements EhSINE1 and EhSINE2. Due to their mobile nature, some EhSINE copies may occupy different genomic locations among isolates of E. histolytica possibly affecting adjacent gene expression; this variability in location can be exploited to differentiate strains. RESULTS We have looked for EhSINE1- and EhSINE2-occupied loci in the genome sequence of Entamoeba histolytica HM-1:IMSS and searched for homologous loci in other strains to determine the insertion status of these elements. A total of 393 EhSINE1 and 119 EhSINE2 loci were analyzed in the available sequenced strains (Rahman, DS4-868, HM1:CA, KU48, KU50, KU27 and MS96-3382. Seventeen loci (13 EhSINE1 and 4 EhSINE2) were identified where a EhSINE1/EhSINE2 sequence was missing from the corresponding locus of other strains. Most of these loci were unoccupied in more than one strain. Some of the loci were analyzed experimentally for SINE occupancy using DNA from strain Rahman. These data helped to correctly assemble the nucleotide sequence at three loci in Rahman. SINE occupancy was also checked at these three loci in 7 other axenically cultivated E. histolytica strains and 16 clinical isolates. Each locus gave a single, specific amplicon with the primer sets used, making this a suitable method for strain typing. Based on presence/absence of SINE and amplification with locus-specific primers, the 23 strains could be divided into eleven genotypes. The results obtained by our method correlated with the data from other typing methods. We also report a bioinformatic analysis of EhSINE2 copies. CONCLUSIONS Our results reveal several loci with extensive polymorphism of SINE occupancy among different strains of E. histolytica and prove the principle that the genomic distribution of SINEs is a valid method for typing of E. histolytica strains.
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Affiliation(s)
- Vandana Kumari
- School of Environmental Sciences, Jawaharlal Nehru University, New Delhi 110067, India
| | - Lakshmi Rani Iyer
- School of Life Sciences, Jawaharlal Nehru University, New Delhi 110067, India
| | - Riti Roy
- School of Computational and Integrative Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Varsha Bhargava
- School of Environmental Sciences, Jawaharlal Nehru University, New Delhi 110067, India
| | - Suchita Panda
- School of Environmental Sciences, Jawaharlal Nehru University, New Delhi 110067, India
| | - Jaishree Paul
- School of Life Sciences, Jawaharlal Nehru University, New Delhi 110067, India
| | - Jaco J Verweij
- Laboratory for Medical Microbiology and Immunology, Laboratory for Clinical Pathology, St. Elisabeth Hospital, Tilburg, The Netherlands
| | - C Graham Clark
- Department of Pathogen Molecular Biology, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
| | - Alok Bhattacharya
- School of Life Sciences, Jawaharlal Nehru University, New Delhi 110067, India
- School of Computational and Integrative Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Sudha Bhattacharya
- School of Environmental Sciences, Jawaharlal Nehru University, New Delhi 110067, India
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Zhang H, Ehrenkaufer GM, Hall N, Singh U. Small RNA pyrosequencing in the protozoan parasite Entamoeba histolytica reveals strain-specific small RNAs that target virulence genes. BMC Genomics 2013; 14:53. [PMID: 23347563 PMCID: PMC3610107 DOI: 10.1186/1471-2164-14-53] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2012] [Accepted: 01/02/2013] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Small RNA mediated gene silencing is a well-conserved regulatory pathway. In the parasite Entamoeba histolytica an endogenous RNAi pathway exists, however, the depth and diversity of the small RNA population remains unknown. RESULTS To characterize the small RNA population that associates with E. histolytica Argonaute-2 (EhAGO2-2), we immunoprecipitated small RNAs that associate with it and performed one full pyrosequencing run. Data analysis revealed new features of the 27nt small RNAs including the 5'-G predominance, distinct small RNA distribution patterns on protein coding genes, small RNAs mapping to both introns and exon-exon junctions, and small RNA targeted genes that are clustered particularly in sections of genome duplication. Characterization of genomic loci to which both sense and antisense small RNAs mapped showed that both sets of small RNAs have 5'-polyphosphate termini; strand-specific RT-PCR detected transcripts in both directions at these loci suggesting that both transcripts may serve as template for small RNA generation. In order to determine whether small RNA abundance patterns account for strain-specific gene expression profiles of E. histolytica virulent and non-virulent strains, we sequenced small RNAs from a non-virulent strain and found that small RNAs mapped to genes in a manner consistent with their regulation of strain-specific virulence genes. CONCLUSIONS We provided a full spectrum analysis for E. histolytica AGO2-2 associated 27nt small RNAs. Additionally, comparative analysis of small RNA populations from virulent and non-virulent amebic strains indicates that small RNA populations may regulate virulence genes.
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Affiliation(s)
- Hanbang Zhang
- Division of Infectious Diseases, Department of Internal Medicine, Stanford University School of Medicine, Stanford, California 94305-5107, USA
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Vicente JB, Ehrenkaufer GM, Saraiva LM, Teixeira M, Singh U. Entamoeba histolytica modulates a complex repertoire of novel genes in response to oxidative and nitrosative stresses: implications for amebic pathogenesis. Cell Microbiol 2008; 11:51-69. [PMID: 18778413 DOI: 10.1111/j.1462-5822.2008.01236.x] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Upon host infection, the protozoan parasite Entamoeba histolytica is confronted with reactive oxygen and nitrogen species and must survive these stresses in order to cause invasive disease. We analysed the parasite's response to oxidative and nitrosative stresses, probing the transcriptional changes of trophozoites of a pathogenic strain after a 60 min exposure to H2O2 (1 mM) or a NO donor (dipropylenetriamine-NONOate, 200 microM), using whole-genome DNA microarrays. Genes encoding reactive oxygen and nitrogen species detoxification enzymes had high transcriptional levels under basal conditions and upon exposure to both stresses. On a whole-genome level, there was significant modulation of gene expression by H2O2 (286 genes regulated) and dipropylenetriamine-NONOate (1036 genes regulated) with a significant overlap of genes modulated under both conditions (164 genes). A number of transcriptionally regulated genes were in signalling/regulatory and repair/metabolic pathways. However, the majority of genes with altered transcription encode unknown proteins, suggesting as yet unraveled response pathways in E. histolytica. Trophozoites of a non-pathogenic E. histolytica strain had a significantly muted transcriptional response to H2O2 compared with the pathogenic strain, hinting that differential response to oxidative stress may be one factor that contributes to the pathogenic potential of E. histolytica.
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Affiliation(s)
- João B Vicente
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305-5107, USA
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Davis PH, Zhang X, Guo J, Townsend RR, Stanley SL. Comparative proteomic analysis of two Entamoeba histolytica strains with different virulence phenotypes identifies peroxiredoxin as an important component of amoebic virulence. Mol Microbiol 2006; 61:1523-32. [PMID: 16968225 DOI: 10.1111/j.1365-2958.2006.05344.x] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Entamoeba histolytica is a protozoan intestinal parasite that causes amoebic colitis and amoebic liver abscess. To identify virulence factors of E. histolytica, we first defined the phenotypes of two E. histolytica strains, HM-1:IMSS, the prototype virulent strain, and E. histolytica Rahman, a strain that was reportedly less virulent than HM-1:IMSS. We found that compared with HM-1:IMSS, Rahman has a defect in erythrophagocytosis and the ability to cause amoebic colitis in human colonic xenografts. We used differential in-gel 2D electrophoresis to compare the proteome of Rahman and HM-1:IMSS, and identified six proteins that were differentially expressed above a fivefold level between the two organisms. These included two proteins with antioxidative properties (peroxiredoxin and superoxide dismutase), and three proteins of unknown function, grainin 1, grainin 2 and a protein containing a LIM-domain. Overexpression of peroxiredoxin in Rahman rendered the transgenic trophozoites more resistant to killing by H2O2 in vitro, and infection with Rahman trophozoites expressing higher levels of peroxiredoxin was associated with higher levels of intestinal inflammation in human colonic xenografts, and more severe disease based on histology. In contrast, higher levels of grainin appear to be associated with a reduced virulence phenotype, and E. histolytica HM-1:IMSS trophozoites infecting human intestinal xenografts show marked decreases in grainin expression. Our data indicate that there are definable molecular differences between Rahman and HM-1:IMSS that may explain the phenotypic differences, and identify peroxiredoxin as an important component of virulence in amoebic colitis.
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Affiliation(s)
- Paul H Davis
- Department of Medicine, Washington University School of Medicine, St Louis, MO, USA
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Davis PH, Schulze J, Stanley SL. Transcriptomic comparison of two Entamoeba histolytica strains with defined virulence phenotypes identifies new virulence factor candidates and key differences in the expression patterns of cysteine proteases, lectin light chains, and calmodulin. Mol Biochem Parasitol 2006; 151:118-28. [PMID: 17141337 DOI: 10.1016/j.molbiopara.2006.10.014] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2006] [Revised: 10/23/2006] [Accepted: 10/25/2006] [Indexed: 11/23/2022]
Abstract
The availability of Rahman, and the virulent HM-1:IMSS strain of E. histolytica, provides a powerful tool for identifying virulence factors of E. histolytica. Here we report an attempt to identify potential virulence factors of E. histolytica by comparing the transcriptome of E. histolytica HM-1:IMSS and E. histolytica Rahman. With phenotypically defined strains, we compared the transcriptome of Rahman and HM-1:IMSS using a custom 70mer oligonucleotide based microarray that has essentially full representation of the E. histolytica HM-1:IMSS genome. We find extensive differences between the two strains, including distinct patterns of gene expression of cysteine proteinases, AIG family members, and lectin light chains.
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Affiliation(s)
- Paul H Davis
- Department of Medicine, Washington University School of Medicine, St. Louis, MO, USA
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Nozaki T, Kobayashi S, Takeuchi T, Haghighi A. Diversity of clinical isolates of Entamoeba histolytica in Japan. Arch Med Res 2006; 37:277-9. [PMID: 16380332 DOI: 10.1016/j.arcmed.2005.09.010] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2005] [Accepted: 09/27/2005] [Indexed: 11/20/2022]
Abstract
In Japan, amebiasis is domestically transmitted by two major populations: male homosexuals and mentally handicapped persons, which is remarkably different from most other developed countries where Entamoeba dispar infection is predominantly observed. Here we briefly summarize epidemiology of amebiasis in Japan. We also review our current understanding of the diversity of Entamoeba histolytica clinical isolates in Japan, based on polymorphic genetic markers, clinical representations, and in vivo virulence, using an animal model.
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Affiliation(s)
- Tomoyoshi Nozaki
- Department of Parasitology, Gunma University Graduate School of Medicine, Showa-machi, Maebashi, Gunma, Japan.
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MacFarlane RC, Singh U. Identification of differentially expressed genes in virulent and nonvirulent Entamoeba species: potential implications for amebic pathogenesis. Infect Immun 2006; 74:340-51. [PMID: 16368989 PMCID: PMC1346599 DOI: 10.1128/iai.74.1.340-351.2006] [Citation(s) in RCA: 107] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Entamoeba histolytica is a protozoan parasite that causes colitis and liver abscesses. Several Entamoeba species and strains with differing levels of virulence have been identified. E. histolytica HM-1:IMSS is a virulent strain, E. histolytica Rahman is a nonvirulent strain, and Entamoeba dispar is a nonvirulent species. We used an E. histolytica DNA microarray consisting of 2,110 genes to assess the transcriptional differences between these species/strains with the goal of identifying genes whose expression correlated with a virulence phenotype. We found 415 genes expressed at lower levels in E. dispar and 32 genes with lower expression in E. histolytica Rahman than in E. histolytica HM-1:IMSS. Overall, 29 genes had decreased expression in both the nonvirulent species/strains than the virulent E. histolytica HM-1:IMSS. Interestingly, a number of genes with potential roles in stress response and virulence had decreased expression in either one or both nonvirulent Entamoeba species/strains. These included genes encoding Fe hydrogenase (9.m00419), peroxiredoxin (176.m00112), type A flavoprotein (6.m00467), lysozyme (6.m00454), sphingomyelinase C (29.m00231), and a hypothetical protein with homology to both a Plasmodium sporozoite threonine-asparagine-rich protein (STARP) and a streptococcal hemagglutinin (238.m00054). The function of these genes in Entamoeba and their specific roles in parasite virulence need to be determined. We also found that a number of the non-long-terminal-repeat retrotransposons (EhLINEs and EhSINEs), which have been shown to modulate gene expression and genomic evolution, had lower expression in the nonvirulent species/strains than in E. histolytica HM-1:IMSS. Our results, identifying expression profiles and patterns indicative of a virulence phenotype, may be useful in characterizing the transcriptional framework of virulence.
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Affiliation(s)
- Ryan C. MacFarlane
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California 94305-5124, Department of Internal Medicine, Division of Infectious Diseases, Stanford University School of Medicine, Stanford, California 94305-5124
| | - Upinder Singh
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California 94305-5124, Department of Internal Medicine, Division of Infectious Diseases, Stanford University School of Medicine, Stanford, California 94305-5124
- Corresponding author. Mailing address: Department of Medicine, Division of Infectious Diseases, S-143 Grant Building, 300 Pasteur Drive, Stanford, CA 94305. Phone: (650) 723-4045. Fax: (650) 724-3892. E-mail:
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Shah PH, MacFarlane RC, Bhattacharya D, Matese JC, Demeter J, Stroup SE, Singh U. Comparative genomic hybridizations of Entamoeba strains reveal unique genetic fingerprints that correlate with virulence. EUKARYOTIC CELL 2005; 4:504-15. [PMID: 15755913 PMCID: PMC1087797 DOI: 10.1128/ec.4.3.504-515.2005] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2004] [Accepted: 12/21/2004] [Indexed: 11/20/2022]
Abstract
Variable phenotypes have been identified for Entamoeba species. Entamoeba histolytica is invasive and causes colitis and liver abscesses but only in approximately 10% of infected individuals; 90% remain asymptomatically colonized. Entamoeba dispar, a closely related species, is avirulent. To determine the extent of genetic diversity among Entamoeba isolates and potential genotype-phenotype correlations, we have developed an E. histolytica genomic DNA microarray and used it to genotype strains of E. histolytica and E. dispar. On the basis of the identification of divergent genetic loci, all strains had unique genetic fingerprints. Comparison of divergent genetic regions allowed us to distinguish between E. histolytica and E. dispar, identify novel genetic regions usable for strain and species typing, and identify a number of genes restricted to virulent strains. Among the four E. histolytica strains, a strain with attenuated virulence was the most divergent and phylogenetically distinct strain, raising the intriguing possibility that genetic subtypes of E. histolytica may be partially responsible for the observed variability in clinical outcomes. This microarray-based genotyping assay can readily be applied to the study of E. histolytica clinical isolates to determine genetic diversity and potential genotypic-phenotypic associations.
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Affiliation(s)
- Preetam H Shah
- Department of Medicine, Division of Infectious Diseases, Stanford University School of Medicine, Stanford, CA, USA
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