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Tharmaratnam T, Kumanan T, Iskandar MA, D’Urzo K, Gopee-Ramanan P, Loganathan M, Tabobondung T, Tabobondung TA, Sivagurunathan S, Patel M, Tobbia I. Entamoeba histolytica and amoebic liver abscess in northern Sri Lanka: a public health problem. Trop Med Health 2020; 48:2. [PMID: 31992948 PMCID: PMC6977265 DOI: 10.1186/s41182-020-0193-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Accepted: 01/16/2020] [Indexed: 12/25/2022] Open
Abstract
Entamoeba histolytica (E. histolytica) is a facultative protozoan parasite implicated in amoebic liver abscesses (ALA), the most common extraintestinal manifestation of this infection. E. histolytica is endemic to sub-tropical and tropical countries and has been a major public health concern in northern Sri Lanka (SLK) for the last three decades. This has been attributed to a multitude of factors such as poor sanitation, hygiene, male sex, middle age, overcrowding, unsanitary practices in the production of indigenous alcoholic beverages, and alcohol consumption. Additionally, while rates of E. histolytica have declined substantially throughout the rest of the island, largely due to better infrastructure, it remains pervasive in the northern peninsula, which is generally less developed. Infection arises primarily from fecal-oral transmission through the consumption of contaminated drinking water containing cysts. Upon ingestion, cysts multiply into trophozoites and colonize the host colonic mucosa using lectin and cysteine proteases as virulence factors, leading to host invasion. Symptoms occur along a spectrum, from asymptomatology, to pyrexia, abdominal cramping, and amoebic dysentery. Colonization of the colon results in the formation of distinct flask-shaped ulcers along the epithelium, and eventual penetration of the lamina propria via the production of matrix metalloproteinases. ALA then develops through trophozoite migration via the mesenteric hepatic portal circulation, where microabscesses coalesce to form a single, large right-lobe abscess, commonly on the posterior aspect. The progression of infection to invasive disease is contingent on the unique interplay between host and pathogen factors, such as the strength of host-immunity to overcome infection and inherent pathogenicity of the Entamoeba species. As a preventable illness, E. histolytica complications such as ALA impose a significant burden on the healthcare system. This mini-review highlights epidemiological trends, risk factors, diagnostic modalities, treatment approaches, and opportunities for prevention of E. histolytica-induced ALA, to help address this endemic problem on the island of SLK.
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Affiliation(s)
- Tharmegan Tharmaratnam
- School of Medicine, Royal College of Surgeons in Ireland, Dublin, Ireland
- School of Medicine, Royal College of Surgeons in Ireland-Bahrain, Busaiteen, Bahrain
| | - Thirunavukarasu Kumanan
- Department of Internal Medicine, Faculty of Medicine, University of Jaffna, Jaffna, Sri Lanka
- Teaching Hospital Jaffna, Faculty of Medicine, University of Jaffna, Jaffna, Sri Lanka
| | - Mina Amin Iskandar
- School of Medicine, Royal College of Surgeons in Ireland, Dublin, Ireland
- School of Medicine, Royal College of Surgeons in Ireland-Bahrain, Busaiteen, Bahrain
| | - Katrina D’Urzo
- School of Medicine, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - Prasaanthan Gopee-Ramanan
- Department of Diagnostic Radiology, Hamilton Health Sciences Centre, Hamilton, ON Canada
- Department of Radiology, Michael G. DeGroote School of Medicine, McMaster University, Hamilton, ON Canada
| | - Mayura Loganathan
- Academic Family Health Team, Mount Sinai Hospital, Faculty of Medicine, University of Toronto, Toronto, ON Canada
- Department of Family and Community Medicine, Faculty of Medicine, University of Toronto, Toronto, ON Canada
| | - Tyler Tabobondung
- Department of Family Medicine, Brantford General Hospital, Hamilton, ON Canada
- Department of Family Medicine, Michael G. DeGroote School of Medicine, McMaster University, Hamilton, ON Canada
| | | | - Seyon Sivagurunathan
- Department of Family Medicine, Michael G. DeGroote School of Medicine, McMaster University, Hamilton, ON Canada
- Stonechurch Family Health Clinic, Department of Family Medicine, Michael G. DeGroote School of Medicine, McMaster University, Hamilton, ON Canada
| | - Mitul Patel
- School of Medicine, Royal College of Surgeons in Ireland-Bahrain, Busaiteen, Bahrain
| | - Iqdam Tobbia
- School of Medicine, Royal College of Surgeons in Ireland, Dublin, Ireland
- School of Medicine, Royal College of Surgeons in Ireland-Bahrain, Busaiteen, Bahrain
- Department of Pathology and Clinical Microbiology, School of Medicine, Royal College of Surgeons in Ireland-Bahrain, Busaiteen, Bahrain
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SINE polymorphism reveals distinct strains of Entamoeba histolytica from North India. Exp Parasitol 2017; 175:28-35. [DOI: 10.1016/j.exppara.2017.01.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Revised: 01/12/2017] [Accepted: 01/24/2017] [Indexed: 11/17/2022]
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Abstract
In most organisms, the nuclear ribosomal RNA (rRNA) genes are highly repetitive and arranged as tandem repeats on one or more chromosomes. In Entamoeba, however, these genes are located almost exclusively on extrachromosomal circular DNA molecules with no clear evidence so far of a chromosomal copy. Such an uncommon location of rRNA genes may be a direct consequence of cellular physiology, as suggested by studies with Saccharomyces cerevisiae mutants in which the rDNA is extrachromosomal. In this review, Sudha Bhattacharya, Indrani Som and Alok Bhattacharya summarize current knowledge on the structural organization and replication of the Entamoeba rDNA plasmids. Other than the rRNAs encoded by these molecules, no protein-coding genes (including ribosomal protein genes) are found on any of them. They are unique among plasmids in that they do not initiate replication from a fixed origin but use multiple sites dispersed throughout the molecule. Further studies should establish the unique biochemical features of Entamoeba that lead to extrachromosomal rDNA.
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Affiliation(s)
- S Bhattacharya
- School of Environmental Sciences, Jawaharlal Nehru University, New Mehrauli Road, New Delhi 110067, India
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Ali IKM, Clark CG, Petri WA. Molecular epidemiology of amebiasis. INFECTION GENETICS AND EVOLUTION 2008; 8:698-707. [PMID: 18571478 DOI: 10.1016/j.meegid.2008.05.004] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2008] [Revised: 04/18/2008] [Accepted: 05/01/2008] [Indexed: 12/13/2022]
Abstract
Entamoeba histolytica, the causative agent of human amebiasis, remains a significant cause of morbidity and mortality in developing countries and is responsible for up to 100,000 deaths worldwide each year. Entamoeba dispar, morphologically indistinguishable from E. histolytica, is more common in humans in many parts of the world. Similarly Entamoeba moshkovskii, which was long considered to be a free-living ameba, is also morphologically identical to E. histolytica and E. dispar, and is highly prevalent in some E. histolytica endemic countries. However, the only species to cause disease in humans is E. histolytica. Most old epidemiological data on E. histolytica are unusable as the techniques employed do not differentiate between the above three Entamoeba species. Molecular tools are now available not only to diagnose these species accurately but also to study intra-species genetic diversity. Recent studies suggest that only a minority of all E. histolytica infections progress to the development of clinical symptoms in the host and there exist population level differences between the E. histolytica strains isolated from the asymptomatic and symptomatic individuals. Nevertheless the underlying factors responsible for variable clinical outcome of infection by E. histolytica remain largely unknown. We anticipate that the recently completed E. histolytica genome sequence and new molecular techniques will rapidly advance our understanding of the epidemiology and pathogenicity of amebiasis.
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Affiliation(s)
- Ibne Karim M Ali
- Division of Infectious Diseases and International Health, University of Virginia Health System, MR4 Building Room 2115, Lane Road, Charlottesville, VA 22908, USA.
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Entamoeba histolytica: Genetic diversity of African strains based on the polymorphism of the serine-rich protein gene. Exp Parasitol 2008; 118:354-61. [DOI: 10.1016/j.exppara.2007.09.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2007] [Revised: 09/16/2007] [Accepted: 09/21/2007] [Indexed: 11/21/2022]
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6
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Clark CG, Alsmark UCM, Tazreiter M, Saito-Nakano Y, Ali V, Marion S, Weber C, Mukherjee C, Bruchhaus I, Tannich E, Leippe M, Sicheritz-Ponten T, Foster PG, Samuelson J, Noël CJ, Hirt RP, Embley TM, Gilchrist CA, Mann BJ, Singh U, Ackers JP, Bhattacharya S, Bhattacharya A, Lohia A, Guillén N, Duchêne M, Nozaki T, Hall N. Structure and content of the Entamoeba histolytica genome. ADVANCES IN PARASITOLOGY 2008; 65:51-190. [PMID: 18063096 DOI: 10.1016/s0065-308x(07)65002-7] [Citation(s) in RCA: 133] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The intestinal parasite Entamoeba histolytica is one of the first protists for which a draft genome sequence has been published. Although the genome is still incomplete, it is unlikely that many genes are missing from the list of those already identified. In this chapter we summarise the features of the genome as they are currently understood and provide previously unpublished analyses of many of the genes.
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Affiliation(s)
- C G Clark
- Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London WC1E 7HT, UK
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Fotedar R, Stark D, Beebe N, Marriott D, Ellis J, Harkness J. Laboratory diagnostic techniques for Entamoeba species. Clin Microbiol Rev 2007; 20:511-32, table of contents. [PMID: 17630338 PMCID: PMC1932757 DOI: 10.1128/cmr.00004-07] [Citation(s) in RCA: 251] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The genus Entamoeba contains many species, six of which (Entamoeba histolytica, Entamoeba dispar, Entamoeba moshkovskii, Entamoeba polecki, Entamoeba coli, and Entamoeba hartmanni) reside in the human intestinal lumen. Entamoeba histolytica is the causative agent of amebiasis and is considered a leading parasitic cause of death worldwide in humans. Although recent studies highlight the recovery of E. dispar and E. moshkovskii from patients with gastrointestinal symptoms, there is still no convincing evidence of a causal link between the presence of these two species and the symptoms of the host. New approaches to the identification of E. histolytica are based on detection of E. histolytica-specific antigen and DNA in stool and other clinical samples. Several molecular diagnostic tests, including conventional and real-time PCR, have been developed for the detection and differentiation of E. histolytica, E. dispar, and E. moshkovskii in clinical samples. The purpose of this review is to discuss different methods that exist for the identification of E. histolytica, E. dispar, and E. moshkovskii which are available to the clinical diagnostic laboratory. To address the need for a specific diagnostic test for amebiasis, a substantial amount of work has been carried out over the last decade in different parts of the world. The molecular diagnostic tests are increasingly being used for both clinical and research purposes. In order to minimize undue treatment of individuals infected with other species of Entamoeba such as E. dispar and E. moshkovskii, efforts have been made for specific diagnosis of E. histolytica infection and not to treat based simply on the microscopic examination of Entamoeba species in the stool. The incorporation of many new technologies into the diagnostic laboratory will lead to a better understanding of the public health problem and measures to control the disease.
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Affiliation(s)
- R Fotedar
- St. Vincent's Hospital, Department of Microbiology, Sydney, Darlinghurst, NSW 2010, Australia
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Sharma M, Vohra H, Bhasin D. Enhanced pro-inflammatory chemokine/cytokine response triggered by pathogenic Entamoeba histolytica : basis of invasive disease. Parasitology 2006; 131:783-96. [PMID: 16336732 DOI: 10.1017/s0031182005008541] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2004] [Revised: 04/22/2005] [Accepted: 06/09/2005] [Indexed: 11/07/2022]
Abstract
The virulence of Entamoeba histolytica is governed by adhesion/colonization in the gut which is mediated by a galactose specific lectin. Two morphologically identical but distinct species i.e. pathogenic E. histolytica and non-pathogenic E. dispar, can be differentiated by distinct epitopes in the lectin. Both species bind to colonic epithelial cells, but only E. histolytica infection induces an inflammatory response and subsequent pathogenesis. Thus, comparing the responses of the intestinal cells to pathogenic and non-pathogenic lectins is a point of interest. The pathogenic lectin causes cytolysis of epithelial and immune-competent cells. Our data (both qualitative and mRNA quantitation) indicate that the epithelial cells responded to E. histolytica lectin with an increased expression of pro-inflammatory IL-2, IL-6, IL-8, MIP-1alpha, MCP-1, RANTES, GROalpha and GMCSF as compared to E. dispar lectin. The pathogenic LCM induced a significant increase in intracellular calcium concentration, proliferative response and chemotaxis of lymphocytes from ALA patients as compared to non-pathogenic LCM. High RANTES and IL-6 were induced in patients' lymphocytes by pathogenic LCM, along with their receptors CCR5 and CD126 as compared to NP-LCM. The local release of such a complex network of cytokines/chemokines could explain the histopathology of E. histolytica infection. The comparative low levels of these chemokines/pro-inflammatory cytokines and high levels of anti-inflammatory IL-10 in response to non-pathogenic E. dispar could explain the absence of an acute inflammatory response and the disease process. The cytokines and chemokines may provide a mechanism for initiation, amplification or containment of inflammation during disease state.
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Affiliation(s)
- M Sharma
- Department of Experimental Medicine and Biotechnology, PGIMER, Chandigarh - 160 012, India
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Clark CG. Methods for the investigation of diversity in Entamoeba histolytica. Arch Med Res 2006; 37:258-62. [PMID: 16380327 DOI: 10.1016/j.arcmed.2005.09.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2005] [Accepted: 09/26/2005] [Indexed: 11/17/2022]
Abstract
The ability to distinguish variants of a species has many potential applications. In Entamoeba histolytica the first method to detect variation was based on isoenzyme analysis. However, this approach has been superseded by DNA-based analysis. In this review I discuss the basis of the variation detected in E. histolytica by the various molecular methods that have been published to date. Information on diversity in other species is mentioned where such information exists.
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Affiliation(s)
- C Graham Clark
- Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK.
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Campos-Rodríguezp R, Jarillo-Luna A. The pathogenicity of Entamoeba histolytica is related to the capacity of evading innate immunity. Parasite Immunol 2005; 27:1-8. [PMID: 15813717 DOI: 10.1111/j.1365-3024.2005.00743.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The host and parasite factors that influence susceptibility to Entamoeba histolytica infection and disease are not well understood. Entamoeba histolytica pathogenicity has been considered by focusing principally on parasite rather than host factors. Thus, research has concentrated on explaining the molecular differences between pathogenic E. histolytica and non-pathogenic E. dispar. However, the amoeba molecules considered most important for host tissue destruction (amoebapore, galactose/N-acetyl galactosamine inhibitable lectin, and cysteine proteinases) are present in both pathogenic E. histolytica and non-pathogenic E. dispar. In addition, the genetic differences in pathogenicity among E. histolytica isolates are unlikely to completely explain the different outcomes of infection. Considering that the principal difference between pathogenic and non-pathogenic amoebas lies in their surface coats, we propose that pathogenicity of the amoebas is related to the composition and properties of the surface coat components (or pathogen-associated molecular patterns, PAMPs), and the ability of innate immune response to recognize these components and eliminate the parasite. According to this hypothesis, a key feature that may distinguish pathogenic (E. histolytica) from non-pathogenic (E. dispar) strains is whether or not they can overcome innate immune defences. A corollary of this hypothesis is that in susceptible individuals the PAMPs are either not recognized or they are recognized by a set of Toll-like receptors (TLRs) that leads to an inflammatory response. In both cases, the result is tissue damage. On the contrary, in resistant individuals the innate/inflammatory response, induced through the activation of a different set of TLRs, eliminates the parasite.
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Affiliation(s)
- Rafael Campos-Rodríguezp
- Departamento de Bioquímica, Escuela Superior de Medicina, Instituto Politécnico Nacional, México, DF.
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Bhattacharya A, Bhattacharya S, Ackers JP. Nontranslated polyadenylated RNAs from Entamoeba histolytica. Trends Parasitol 2003; 19:286-9. [PMID: 12855374 DOI: 10.1016/s1471-4922(03)00121-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Protozoan parasites display a range of unusual molecular mechanisms that could be helpful for their survival in Nature. Among these parasites, Entamoeba histolytica is one of the most prevalent in developing countries such as India. Entamoeba histolytica produces at least four different unusual transcripts, IE, Tr, ehapt1 and UEE1, that are polyadenylated, but do not have significant open reading frames. Availability of large-scale sequence information has helped us to understand the nature of these sequences and their possible role. Entamoeba histolytica also encodes at least three classes of non-long-terminal-repeats containing retrotransposons, similar to mammalian long retrotransposable elements. This article describes the current status of our understanding of these transcripts and suggests a relationship between some of these transcripts and short retrotransposable element-like retro-elements present in many eukaryotes.
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Affiliation(s)
- Alok Bhattacharya
- School of Life Sciences, Jawaharlal Nehru University, 110 067, New Delhi, India
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12
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Abstract
Amoebiasis is the second leading cause of death from parasitic disease worldwide. The causative protozoan parasite, Entamoeba histolytica, is a potent pathogen. Secreting proteinases that dissolve host tissues, killing host cells on contact, and engulfing red blood cells, E histolytica trophozoites invade the intestinal mucosa, causing amoebic colitis. In some cases amoebas breach the mucosal barrier and travel through the portal circulation to the liver, where they cause abscesses consisting of a few E histolytica trophozoites surrounding dead and dying hepatocytes and liquefied cellular debris. Amoebic liver abscesses grow inexorably and, at one time, were almost always fatal, but now even large abscesses can be cured by one dose of antibiotic. Evidence that what we thought was a single species based on morphology is, in fact, two genetically distinct species--now termed Entamoeba histolytica (the pathogen) and Entamoeba dispar (a commensal)--has turned conventional wisdom about the epidemiology and diagnosis of amoebiasis upside down. New models of disease have linked E histolytica induction of intestinal inflammation and hepatocyte programmed cell death to the pathogenesis of amoebic colitis and amoebic liver abscess.
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Affiliation(s)
- Samuel L Stanley
- Department of Medicine, Washington University School of Medicine, 660 South Euclid Avenue, St Louis, MO, St Louis, MO 63110, USA.
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Haghighi A, Kobayashi S, Takeuchi T, Masuda G, Nozaki T. Remarkable genetic polymorphism among Entamoeba histolytica isolates from a limited geographic area. J Clin Microbiol 2002; 40:4081-90. [PMID: 12409379 PMCID: PMC139687 DOI: 10.1128/jcm.40.11.4081-4090.2002] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In order to understand genetic polymorphisms among Entamoeba histolytica strains in a limited geographic area and among restricted social populations, we studied nucleotide polymorphism in DNA regions that do not encode proteins (locus 1-2 and locus 5-6) and in genes coding for chitinase and for serine-rich E. histolytica protein. Thirty E. histolytica isolates from domestically infected Japanese amebiasis patients (male homosexuals and residents in institutions for the mentally handicapped) and four reference strains were examined. PCR revealed remarkable polymorphisms in both the number and size of the PCR fragments containing these loci. Polymorphisms in lengths, types, and numbers of internal repeat units were observed in locus 1-2 and the repeat-containing region of serine-rich E. histolytica protein among the Japanese isolates. In contrast, polymorphism at locus 5-6 was observed almost exclusively in the number of repeats of a 16-nucleotide unit. The repeat-containing region of chitinase appeared to be the least polymorphic among the four loci with a single dominant genotype representing 66% (20 out of 30) of all of the isolates. Isolates obtained from male homosexuals showed a more complex genetic polymorphism than those from residents in institutions. Considering all four polymorphic loci together, all 19 Japanese isolates from male homosexuals were distinct. In contrast, all isolates obtained from mass-infection cases at a single institution had an identical genotype, suggesting that these cases were caused by a single E. histolytica strain. No significant correlation was found between genotypes and zymodemes or between genotypes and clinical presentations, e.g., colitis or liver abscess. Certain genotypes were observed with higher frequencies in male homosexuals or residents of institutions. These data indicate that genotyping of the E. histolytica isolates by using these four polymorphic loci could serve as a tool to fingerprint individual isolates. We propose that genotyping of ameba isolates should help to determine geographic origins of isolates and routes of transmission.
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Affiliation(s)
- Ali Haghighi
- Department of Parasitology, National Institute of Infectious Diseases, Shinjuku-ku. Department of Tropical Medicine and Parasitology, Keio University School of Medicine, Shinjuku-ku. Tokyo Metropolitan Kiyose Children's Hospital, Kiyose-shi, Tokyo, Japan
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14
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Ayeh-Kumi PF, Ali IM, Lockhart LA, Gilchrist CA, Petri WA, Haque R. Entamoeba histolytica: genetic diversity of clinical isolates from Bangladesh as demonstrated by polymorphisms in the serine-rich gene. Exp Parasitol 2001; 99:80-8. [PMID: 11748961 DOI: 10.1006/expr.2001.4652] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The varied organ tropisms and clinical presentations of infection by Entamoeba histolytica have stimulated interest in the role of parasite genetic diversity in virulence. We investigated genetic diversity among 54 E. histolytica isolates from Bangladesh by analyzing polymorphism in the serine-rich gene by nested PCR on DNA extracted from stool and liver aspirate pus. We detected both size and restriction site polymorphisms among the isolates within this endemic area. A combination of the nested PCR results and the AluI digestion of the PCR products examined yielded 25 distinct DNA banding patterns among the 42 stool isolates and an additional 9 distinct patterns among the 12 liver abscess isolates. Approximately half of the isolates had unique polymorphisms. Interestingly, the majority of E. histolytica from the liver had polymorphisms which were not present in intestinal isolates from the same geographic area. These data are consistent with the existence of genetic differences between E. histolytica which cause intestinal and those which cause hepatic disease. We conclude that there is genetic diversity within E. histolytica isolates from an endemic population as reflected in serine-rich E. histolytica protein gene polymorphism. The correlation of genetic differences with the pathogenic potential of E. histolytica strains and the implications of genetic diversity for the immunoprophylaxis of amebiasis require further study.
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Affiliation(s)
- P F Ayeh-Kumi
- Department of Medicine, University of Virginia Health System, Charlottesville, Virginia 22908-1340, USA
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15
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Ghosh S, Zaki M, Clark CG, Bhattacharya S. Recombinational loss of a ribosomal DNA unit from the circular episome of Entamoeba histolytica HM-1:IMSS. Mol Biochem Parasitol 2001; 116:105-8. [PMID: 11463474 DOI: 10.1016/s0166-6851(01)00305-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Affiliation(s)
- S Ghosh
- School of Life Sciences, Jawaharlal Nehru University, New Delhi 110 067, India
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16
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Zaki M, Clark CG. Isolation and characterization of polymorphic DNA from Entamoeba histolytica. J Clin Microbiol 2001; 39:897-905. [PMID: 11230401 PMCID: PMC87847 DOI: 10.1128/jcm.39.3.897-905.2001] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
An important gap in our understanding of the epidemiology of amebiasis is what determines the outcome of Entamoeba histolytica infections. To investigate the possible existence of invasive and noninvasive strains as one factor, the ability to differentiate individual isolates of E. histolytica is necessary. Two new loci containing internal repeats, locus 1-2 and locus 5-6, have been isolated. Each contains a single repeat block with two types of related direct repeats arranged in tandem. Southern blot analysis suggests that both loci are multicopy and may themselves be arranged in tandem arrays. Three other previously reported, internally repetitive loci containing at least two repeat blocks each with one or more related repeat units were also investigated. PCR was used to study polymorphism at each of these loci, which was detected to various degrees in each case. Variation was seen in the total number of bands obtained per isolate and their sizes. Nucleotide sequence comparison of loci 1-2 and 5-6 in five axenic isolates revealed differences in the number of repeat units, which correlated with the observed PCR product size variation, and in repeat sequence. Use of multiple loci collectively allowed differentiation of a majority of the 13 isolates studied, and we believe that these loci have the potential to be used as polymorphic molecular markers for investigating the epidemiology of E. histolytica and the potential existence of genetically distinct invasive and noninvasive strains.
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Affiliation(s)
- M Zaki
- Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, United Kingdom
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17
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Abstract
Estimation of genome size of Entamoeba histolytica by different methods has failed to give comparable values due to the inherent complexities of the organism, such as the uncertain level of ploidy, presence of multinucleated cells and a poorly demarcated cell division cycle. The genome of E. histolytica has a low G+C content (22.4%), and is composed of both linear chromosomes and a number of circular plasmid-like molecules. The rRNA genes are located exclusively on some of the circular DNAs. Karyotype analysis by pulsed field gel electrophoresis suggests the presence of 14 conserved linkage groups and an extensive size variation between homologous chromosomes from different isolates. Several repeat families have been identified, some of which have been shown to be present in all the electrophoretically separated chromosomes. The typical nucleosomal structure has not been demonstrated, though most of the histone genes have been identified. Most Entamoeba genes lack introns, have short 3' and 5' untranslated regions, and are tightly packed. Promoter analysis revealed the presence of three conserved motifs and several upstream regulatory elements. Unlike typical eukaryotes, the transcription of protein coding genes is alpha-amanitin resistant. Expressed Sequence Tag analysis has identified a group of highly abundant polyadenylated RNAs which are unlikely to be translated. The Expressed Sequence Tag approach has also helped identify several important genes which encode proteins that may be involved in different biochemical pathways, signal transduction mechanisms and organellar functions.
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Affiliation(s)
- A Bhattacharya
- School of Life Sciences, Jawaharlal Nehru University, New Mehrauli Road, New Delhi, India.
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18
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Sharma R, Azam A, Bhattacharya S, Bhattacharya A. Identification of novel genes of non-pathogenic Entamoeba dispar by expressed sequence tag analysis. Mol Biochem Parasitol 1999; 99:279-85. [PMID: 10340493 DOI: 10.1016/s0166-6851(99)00018-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Affiliation(s)
- R Sharma
- School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
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19
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Abstract
The application of molecular biologic techniques over the past decade has seen a tremendous growth in our knowledge of the biology of Entamoeba histolytica, the causative agent of amebic dysentery and amebic liver abscess. This approach has also led to the identification and structural characterization of three amebic antigens, the serine-rich Entamoeba histolytica protein (SREHP), the 170-kDa subunit of the Gal/GalNAc binding lectin, and the 29-kDa cysteine-rich protein, which all show promise as recombinant antigen-based vaccines to prevent amebiasis. In recent studies, an immunogenic dodecapeptide derived from the SREHP molecule has been genetically fused to the B subunit of cholera toxin, to create a recombinant protein capable of inducing both antiamebic and anti-cholera toxin antibodies when administered by the oral route. Continued progress in this area will bring us closer to the goal of a cost-effective oral combination "enteric pathogen" vaccine, capable of inducing protective mucosal immune responses to several clinically important enteric diseases, including amebiasis.
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Affiliation(s)
- S L Stanley
- Department of Medicine and Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri 63110, USA.
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20
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Abstract
The intestinal protozoan parasite Entamoeba histolytica causes amebic dysentery and amebic liver abscess, and ranks third worldwide among parasitic causes of death. The application of molecular techniques to the study of this organism have led to major advances in understanding the pathophysiology of amebic infection. This article reviews what is currently known about the pathogenesis, clinical manifestations, diagnosis, and treatment of amebiasis.
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Affiliation(s)
- E Li
- Division of Gastroenterology, Washington University School of Medicine, St. Louis, Missouri, USA
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21
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Cruz-Reyes J, ur-Rehman T, Spice WM, Ackers JP. A novel transcribed repeat element from Entamoeba histolytica. Gene 1995; 166:183-4. [PMID: 8529889 DOI: 10.1016/0378-1119(95)00549-x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
We have identified an unusual 0.55-kb DNA repeat element specific to Entamoeba histolytica (Eh) which we call interspersed element (IE). The IE is a common feature in independently isolated genomic and cDNA fragments. Hybridization of labeled IE sequences to trophozoite DNA, RNA and first-strand cDNA prepared from poly(A)-enriched mRNA indicate that the IE are reiterated about 500 times per Eh trophozoite and that one or more can be found as RNA transcripts. These features and the degree of conservation of IE suggest a possible role for these sequences.
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Affiliation(s)
- J Cruz-Reyes
- Department of Medical Parasitology, London School of Hygiene and Tropical Medicine, UK
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22
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González CR, Isibasi A, Ortiz-Navarrete V, Paniagua J, García JA, Ramirez A, Salvatierra B, Tapia R, Sepúlveda J, Gutiérrez G. Prevalence of antibodies against Entamoeba histolytica in Mexico measured by ELISA. Epidemiol Infect 1995; 115:535-43. [PMID: 8557086 PMCID: PMC2271580 DOI: 10.1017/s0950268800058702] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
The prevalence of antibodies against Entamoeba histolytica was studied in the Mexican population using an immunoenzyme assay in solid phase (ELISA) and semiautomatic equipment. The antigen was a mixture of membrane proteins obtained by Triton X-100 extraction from an axenic culture of Entamoeba histolytica HM1-IMSS. The method was standardized by comparing serum samples from amoebic liver abscess patients with healthy volunteers. From the 60,538 samples supplied by the National Seroepidemiology Survey, antibodies were found in 4.49% (4.32-4.65% at 95% confidence limit). More significant titres occurred in the central region of the country. The ratio female to male was 1.25:1. The population living in metropolitan areas had probably been infected at a younger age than those living in the country. Important differences were found in the seroprevalence obtained by ELISA compared with a study which used indirect haemagglutination (IHA) in the same sample frame.
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Affiliation(s)
- C R González
- Laboratorio de Inmunoquímica, Centro Médico Nacional Siglo XXI, Instituto Mexicano del Seguro Social, México, D.F., México
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23
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24
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Abstract
DNA probe and PCR-based assays to identify and detect parasites are technically complex; however, they have high sensitivity, directly detect parasites independent of the immunocompetence or previous clinical history of the patient, and can distinguish between organisms that are morphologically similar. Diagnosis of parasites is often based on direct detection by microscopy, which is insensitive and laborious and can lack specificity. Most PCR-based assays were more sensitive than DNA probe assays. The development of PCR-based diagnostic assays requires multiple steps following the initial selection of oligonucleotide primers and reporter probe. Generally, the ability to detect the DNA of one parasite was attained by PCR; however, advances in the preparation of samples for PCR (extraction of DNA while removing PCR inhibitors) will be required to achieve that sensitivity with human specimens. Preliminary PCR systems have been developed for many different parasites, yet few have been evaluated with a large number of clinical specimens and/or under field conditions. Those evaluations are essential for determination of clinical and field utility and performance and of the most appropriate application of the assay. Several situations in which PCR-based diagnosis will result in epidemiologic, medical, or public health advances have been identified.
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Affiliation(s)
- J B Weiss
- Department of Infectious Diseases, Roche Molecular Systems, Alameda, California 94501
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25
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Sehgal D, Mittal V, Ramachandran S, Dhar SK, Bhattacharya A, Bhattacharya S. Nucleotide sequence organisation and analysis of the nuclear ribosomal DNA circle of the protozoan parasite Entamoeba histolytica. Mol Biochem Parasitol 1994; 67:205-14. [PMID: 7870125 DOI: 10.1016/0166-6851(94)00129-4] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
We have sequenced the extrachromsomal ribosomal DNA (rDNA) circle of the human protozoan parasite Entamoeba histolytica HM-1:IMSS and present here the complete sequence organisation of the 24.5-kb molecule. Each circle contains two 5.9-kb rDNA transcription units organised as inverted repeats. The regions downstream (3543 bp) and upstream (9216 bp) of the rDNAs contain various families of short tandem repeats. Some of the upstream repeats share extensive sequence homology with the downstream repeats. In addition to the rDNAs themselves, the rDNA circle appears to code for only one other transcript which is 0.7 kb in size as seen in Northern blots. From DNA sequence analysis, no open reading frame could be assigned to the transcript. Extrachromosomal rDNA circles also exist in other E. histolytica strains. Restriction enzyme maps of rDNA circles were constructed from E. histolytica strains 200:NIH, HK-9 and Rahman; and Entamoeba moshkovskii strain Laredo. Striking differences were observed in the organisation of some of them, e.g. the HK-9, Rahman and Laredo circles contained only one rDNA unit and lacked the 0.7-kb transcript sequence. The short repeat sequences upstream and downstream of rDNAs were present in HK-9 and Rahman but absent in Laredo. Circles with one rDNA unit may be derived from those with two units by homologous recombination at direct repeat sequences located upstream and downstream of the two rDNAs.
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Affiliation(s)
- D Sehgal
- School of Life Sciences, Jawaharlal Nehru University, New Delhi, Indiana
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26
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Yang W, Li E, Kairong T, Stanley SL. Entamoeba histolytica has an alcohol dehydrogenase homologous to the multifunctional adhE gene product of Escherichia coli. Mol Biochem Parasitol 1994; 64:253-60. [PMID: 7935603 DOI: 10.1016/0166-6851(93)00020-a] [Citation(s) in RCA: 81] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Entamoeba histolytica ferments glucose to ethanol under the anaerobic conditions of the human colon. There is special interest in this metabolic pathway because it provides an opportunity for parasite-specific chemotherapy. Peptide sequences from a 97-kDa E. histolytica protein, which was originally isolated because of extracellular matrix binding properties, were used to clone and sequence a gene that was found to encode an E. histolytica alcohol dehydrogenase and acetaldehyde dehydrogenase (EhADH2). The EhADH2 cDNA clone had an open reading frame encoding 870 amino acids with a predicted molecular weight of 95,758. The EhADH2 cDNA clone was identical in 48% of its amino acids to the multifunctional enzyme (alcohol dehydrogenase, acetyl-CoA reductase, and pyruvate-formate-lyase-deactivase) encoded by the Escherichia coli adhE gene. The isolation of the EhADH2 protein helps define a new family of ADH enzymes that may be specific to anaerobic and facultatively anaerobic organisms.
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Affiliation(s)
- W Yang
- Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110
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27
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Orozco E, Lazard D, Sanchez T, Sanchez MA, Hernandez R, Silva EF. A variable DNA region of Entamoeba histolytica is expressed in several transcripts which differ in genetically related clones. MOLECULAR & GENERAL GENETICS : MGG 1993; 241:271-9. [PMID: 8246880 DOI: 10.1007/bf00284678] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
A highly variable DNA region (EhVR1), isolated from Entamoeba histolytica clone A, strain HM1:IMSS, is transcribed into several transcripts, which differ in genetically related clones. EhVR1 (3.5 kb) is composed of two contiguous fragments; one of these 1.9 kb long, at the 3' end, identified similar transcripts in clones A, L6 and C2 (all derived from strain HM1:IMMS), the other of 1.6 kb, at the 5' end, detected 0.5, 0.6 and 0.7 kb transcripts only in clone A. Variability of the 1.6 kb fragment was found even within the same clone maintained under different conditions. EhVR1 was localized to 1.3 and 1.4 Mb linear chromosomes and also found in circular molecules. The sequence of the 1.6 kb fragment revealed the presence of a large number of different repeats, including inverted and palindromic repeats. A p145 sequence, previously detected in episomal DNA of the amoeba, was found at the 5' end of EhVR1. The presence of EhVR1 in linear and circular molecules, its high number of repeats, and its variability in genetically related clones suggest the existence of DNA regions that undergo dynamic non-reciprocal recombination between circular episomes and linear chromosomes, and may thus contribute to variability in the trophozoite genome.
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Affiliation(s)
- E Orozco
- Department of Experimental Pathology, Centro de Investigacion y de Estudias Avonzados del I.P.N., Mexico, D.F
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28
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29
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30
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Prasad R, Tola M, Bhattacharya S, Sharma MP, Bhattacharya A. Recognition of Entamoeba histolytica lipophosphoglycan by a strain-specific monoclonal antibody and human immune sera. Mol Biochem Parasitol 1992; 56:279-87. [PMID: 1283004 DOI: 10.1016/0166-6851(92)90177-l] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Western blot analysis showed that the monoclonal antibody 2D7.10 recognized lipophosphoglycan (LPG) from Entamoeba histolytica HM-1:IMSS. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) pattern of [3H]galactose-labeled LPG and Western blot analysis of total lysate of E. histolytica with 2D7.10 revealed patterns similar to that of LPG with 2D7.10. This antibody could also immunoprecipitate purified LPG from the strain HM-1:IMSS after biosynthetically labeling with [3H]galactose and [32P]orthophosphate. However, no immunoprecipitation was observed when 2D7.10 was incubated with [32P]orthophosphate-labeled purified LPG from strain 200:NIH. Sera from patients suffering from invasive amoebiasis also immunoprecipitated 32P-labeled, purified LPG and could immunostain this molecule in Western blots. The human immune sera recognized carbohydrate epitopes but not the associated polypeptides of LPG, as evidenced by sensitivity to periodate digestion, mild acid hydrolysis but not to pronase treatment. It was earlier shown that 2D7.10 binds a carbohydrate epitope in a subset of axenized pathogenic strains of E. histolytica and that this epitope undergoes changes when cultured along with bacteria. These observations suggest that the E. histolytica LPG contains a strain-specific, variable epitope and that LPG is immunogenic in human.
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Affiliation(s)
- R Prasad
- School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
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31
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Cruz-Reyes JA, Spice WM, Rehman T, Gisborne E, Ackers JP. Ribosomal DNA sequences in the differentiation of pathogenic and non-pathogenic isolates of Entamoeba histolytica. Parasitology 1992; 104 ( Pt 2):239-46. [PMID: 1594290 DOI: 10.1017/s0031182000061679] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Recombinant ribosomal DNA sequences were amplified by PCR and used as probes to perform a fingerprint analysis of total DNA from different Entamoeba histolytica isolates. RFLPs obtained with one of the probes, R-1, support previous proposals that pathogenic and non-pathogenic E. histolytica are closely related, yet genotypically distinct. Another probe, R-2, while not distinguishing between the two forms of E. hystolytica, was able to differentiate between them and E. moshkovskii, which has morphologically identical cysts and trophozoites. A third probe, BR-1, identified strain-specific RFLPs.
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Affiliation(s)
- J A Cruz-Reyes
- Department of Medical Parasitology, London School of Hygiene and Tropical Medicine
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32
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Stanley SL, Li E. Isolation of an Entamoeba histolytica cDNA clone encoding a protein with a putative zinc finger domain. Mol Biochem Parasitol 1992; 50:185-7. [PMID: 1542313 DOI: 10.1016/0166-6851(92)90256-j] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- S L Stanley
- Department of Medicine, Washington University School of Medicine, Saint Louis, MO 63110
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33
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Tachibana H, Kobayashi S, Paz KC, Aca IS, Tateno S, Ihara S. Analysis of pathogenicity by restriction-endonuclease digestion of amplified genomic DNA of Entamoeba histolytica isolated in Pernambuco, Brazil. Parasitol Res 1992; 78:433-6. [PMID: 1495923 DOI: 10.1007/bf00931701] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The pathogenicity of 47 strains of Entamoeba histolytica isolated in Pernambuco, Brazil, was examined using the polymerase chain reaction (PCR) followed by restriction-endonuclease digestion. Electrophoretic patterns of PCR products digested with HinfI revealed that all strains were nonpathogenic. The results were entirely in accord with phenotypic properties such as isoenzyme patterns and the failure to bind a pathogenic-isolate-specific monoclonal antibody. When the sensitivity of PCR was examined, amplified products could be detected from template DNA equivalent to five trophozoites. These observations indicate that PCR amplification of genomic DNA and subsequent restriction-enzyme digestion is a useful strategy for obtaining a sensitive and accurate diagnosis. The present study also demonstrates that nonpathogenic strains of E. histolytica predominate in northeastern Brazil.
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Affiliation(s)
- H Tachibana
- Laboratório de Imunopatologia Prof. Keizo Asami, Universidade Federal de Pernambuco, Recife, Brazil
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34
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Brasileiro Filho G, Pena SD. Molecular biological techniques for the diagnosis of infectious diseases. Rev Soc Bras Med Trop 1992; 25:59-71. [PMID: 1308067 DOI: 10.1590/s0037-86821992000100009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Affiliation(s)
- G Brasileiro Filho
- Departamentos de Anatomia Patológica, Faculdade de Medicina e de Bioquímica e Imunologia, Universidade Federal de Minas Gerais, Belo Horizonte, M.G
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