Entamoeba

Abstract
This study has been conducted for the period from the first of March 2014 until September 2014 and included the auditors to Diwaniya General Hospital and Women's Hospital and children in the province of Diwaniya and civil analytical laboratories in the province. A sample of 679 of auditors' stool have been examined by using the direct swab from different age groups and both sexes. The study shows that 61.26% of people have been infected by screened amoeba parasite. The infected rate of both sexes is 58.2% and 41.9%, respectively, but it does not show significant differences between them. The study also shows that the different age groups and different infected rates are the highest in the age group 1-15 years and the lowest rate in the age group 65 years and over(76.68% and 0.7%), respectively and the study does not show significant differences that are statistically significant in the infected rate of the population of the city and the countryside. The infection rate is 52.4% and 47.6%, respectively. The monthly distribution of infection shows that the highest percentage of infection is in August (31.49%) and the lowest is in March (7.93%). The impact of the quality of drinking water used on the emergence of the infection has been also noted which amounts (83.89%) in people who drink sterile or distilled water and (16.1%) in people who drink non-sterile or undistilled water. Also, it has been noted that the emergence of the highest infections in financially poor families in (787.78%) rate. Finally, it is observed that there are differences in the rate of infection among individuals who keep animals in their homes, but they are not significant statistically.
Keyward: E. histolytica , E. dispar , E. moshkoviskii

The evolutionarily conserved proto-oncogene c-myc is involved in both proliferation and differentiation processes of higher eukaryotic cells. We report here the identification and characterization of sequences homologous to c-myc in differentEntamoeba species using a fragment of the mammalian c-myc gene as a probe. This probe hybridized with fragments of 3.5 and 3.4 kilobases (kb) inE. histolytica HindIII ofEcoRI digested DNA. InE. invadens it recognized fragments of 3.1 and 2.8 kb, and in Laredo strain (reported asE. moshkovskii by Clark and Diamond in 1991) the probe hybridized with fragments of 17 kb. The c-myc probe identified transcripts of 3.3 and 1.5 kb inE. histolytica, transcripts of 1.8 and 1.3 kb in Laredo strain, and transcripts of 3.7, 1.8, 1.5 and 1.1 kb inE. invadens. Antibodies against a highly conserved region of the c-myc protein recognized inE. histolytica polypeptides of 35, 40, and 60 kDa. The expression of the 60 kDa polypeptide was temperature-inducible in Laredo strain. InE. invadens a 110 kDa strong band was detected by the antibodies. Surprisingly,E. invadens myc-like sequences and proteins showed greater homology to mammalian c-myc gene and proteins. Expression of proteins antigenically related to c-myc varied according to the cell cycle phase ofE. histolytica. These proteins peaked during D, G1, and S phases and declined during G2.

Covalent modification of proteins by ubiquitin (Ub) and ubiquitin-like modifiers (Ubls) regulates many cellular functions in eukaryotes. These modifications are likely to be associated with pathogenesis, growth, and development of many protozoan parasites but molecular details about this pathway are unavailable for most protozoa. This study presents an analysis of the Ub pathway in three members of the Entamoeba species. Using bioinformatics tools we have identified all Ub and Ubl genes along with their corresponding activating, conjugating, and ligating enzymes (E1, E2s, and E3s) in three Entamoeba species, Entamoeba histolytica, Entamoeba dispar, and Entamoeba invadens. Phylogenetic trees were established for the identified E2s and RING finger E3s using maximum-likelihood method to infer the relationship among these proteins. In silico co-domain analysis of RING finger E3s implicates these proteins in a variety of functions. Several known and putative regulatory motifs were identi...

The evolutionarily conserved proto-oncogene c-myc is involved in both proliferation and differentiation processes of higher eukaryotic cells. We report here the identification and characterization of sequences homologous to c-myc in differentEntamoeba species using a fragment of the mammalian c-myc gene as a probe. This probe hybridized with fragments of 3.5 and 3.4 kilobases (kb) inE. histolytica HindIII ofEcoRI digested DNA. InE. invadens it recognized fragments of 3.1 and 2.8 kb, and in Laredo strain (reported asE. moshkovskii by Clark and Diamond in 1991) the probe hybridized with fragments of 17 kb. The c-myc probe identified transcripts of 3.3 and 1.5 kb inE. histolytica, transcripts of 1.8 and 1.3 kb in Laredo strain, and transcripts of 3.7, 1.8, 1.5 and 1.1 kb inE. invadens. Antibodies against a highly conserved region of the c-myc protein recognized inE. histolytica polypeptides of 35, 40, and 60 kDa. The expression of the 60 kDa polypeptide was temperature-inducible in Laredo strain. InE. invadens a 110 kDa strong band was detected by the antibodies. Surprisingly,E. invadens myc-like sequences and proteins showed greater homology to mammalian c-myc gene and proteins. Expression of proteins antigenically related to c-myc varied according to the cell cycle phase ofE. histolytica. These proteins peaked during D, G1, and S phases and declined during G2.

Entamoeba histolytica (Eh) and Entamoeba dispar (Ed) are protozoan parasites that infect hundreds of millions of persons. In the colonic lumen, amebae form chitin-walled cysts, the infectious stage of the parasite. Entamoeba invadens (Ei), which infects reptiles and is a model for amebic encystation, produces chitin synthase and chitinase during encystation. Ei cyst formation is blocked by the chitinase-inhibitor allosamidin. Here molecular cloning techniques were used to identify homologous genes of Eh, Ed, and Ei that encode chitinases (EC 3.2.1.14). The Eh gene (Eh cht1) predicts a 507-amino acid (aa) enzyme, which has 93 and 74% positional identities with Ed and Ei chitinases, respectively. The Entamoeba chitinases have signal sequences, followed by acidic and hydrophilic sequences composed of multiple tandemly arranged 7-aa repeats (Eh and Ed) or repeats varying in length (Ei). The aa compositions of the chitinase repeats are similar to those of the repeats of the Eh and Ed Ser-rich proteins. The COOH-terminus of each chitinase has a catalytic domain, which resembles those of Brugia malayi (33% positional identity) and Manduca sexta (29%). Recombinant Entamoeba chitinases are precipitated by chitin and show chitinase activity with chitooligosacharide substrates. Consistent with previous biochemical data, chitinase mRNAs are absent in Ei trophozoites and accumulate to maximal levels in Ei encysting for 48 h.

Variable phenotypes have been identified forEntamoebaspecies.Entamoeba histolyticais invasive and causes colitis and liver abscesses but only in ∼10% of infected individuals; 90% remain asymptomatically colonized.Entamoeba dispar, a closely related species, is avirulent. To determine the extent of genetic diversity amongEntamoebaisolates and potential genotype-phenotype correlations, we have developed anE. histolyticagenomic DNA microarray and used it to genotype strains ofE. histolyticaandE. 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 betweenE. histolyticaandE.dispar, identify novel genetic regions usable for strain and species typing, and identify a number of genes restricted to virulent strains. Among the fourE. histolyticastrains, a strain with attenuated virulence was the most divergent and phylogenetically distinct strain, raising the intrigu...

Six ssrRNA gene sequences were obtained by PCR amplification of DNA from uninucleated Entamoeba cysts isolated from fresh faeces of sheep, cows, a roe deer and a reindeer. Phylogenetic analysis using sequences of non-, uni-, quadri- and octonucleate cyst-producing Entamoeba spp. for comparison showed that all six isolates formed a separate clade nested within the clade of quadrinucleate cyst producers. The data indicate that Entamoeba bovis can be isolated from ruminant hosts other than cattle, and we suggest that organisms clustering with the sheep and cattle isolates analysed in the present study be named E. bovis.

Malaria and anaemia (Haemoglobin <11 g/dl) remain frequent in tropical regions and are closely associated. Although anaemia aetiologies are known to be multi-factorial, most studies in malaria endemic areas have been confined to analysis of possible associations between anaemia and individual factors such as malaria. A case control study involving children aged from 1 to 10 years was conducted to assess some assumed contributors to anaemia in the area of Bonconto Health post in Senegal. Study participants were randomly selected from a list of children who participated in a survey in December 2010. Children aged from 1 to 10 years with haemoglobin level below 11 g/dl represented cases (anaemic children). Control participants were eligible if of same age group and their haemoglobin level was >= 11 g/dl. For each participant, a physical examination was done and anthropometric data collected prior to a biological assessment which included: malaria parasitaemia infection, intestinal worm carriage, G6PD deficiency, sickle cell disorders, and alpha-talassaemia. Three hundred and fifty two children < 10 years of age were enrolled (176 case and 176 controls). In a logistic regression analysis, anaemia was significantly associated with malaria parasitaemia (aOR=5.23, 95%CI[1.1-28.48]), sickle cell disorders (aOR=2.89, 95%CI[1,32-6.34]), alpha-thalassemia (aOR=1.82, 95%CI[1.2-3.35]), stunting (aOR=3.37, 95%CI[1.93-5.88], age ranged from 2 to 4 years (aOR=0.13, 95%CI[0.05-0.31]) and age > 5 years (aOR=0.03, 95%CI[0.01-0.08]). Stratified by age group, anaemia was significantly associated with stunting in children less than 5 years (aOR=3.1 95%CI[1.4 - 6.8]), with, sickle cell disorders (aOR=3.5 95%CI [1.4 - 9.0]), alpha-thalassemia (or=2.4 95%CI[1.1-5.3]) and stunting (aOR=3.6 95%CI [1.6-8.2]) for children above 5 years. No association was found between G6PD deficiency, intestinal worm carriage and children's gender. Malaria parasitaemia, stunting and haemoglobin genetic disorders represented the major causes of anaemia among study participants. Anaemia control in this area could be achieved by developing integrated interventions targeting both malaria and malnutrition.

The present study was conducted to investigate the infection of Entamoeba spp by using molecular technique (Quantitative real time polymerase chain reaction) of primers and probes for gene 18S rRNA . The results revealed the presence of Entamoeba histolytica in the percentage (74%) of 200 Entamoeba microscopic positive samples. Also three primers were used in this study for detection the gene of virulence factor of Entamoeba histolytica. The Cysteine protease revealed the high percentage(86.6%) of infection then Amebopore gene (80.35%) whereas Gal/lectin gene gave the lowest (7 5%) ,without significant differences at (p<0.05).

The current media for axenic cultivation of Entamoeba histolytica and Entamoeba invadens are supplemented with bovine or equine serum, which provides several essential nutrients to amoebas. Serum has also been considered an essential component in encystation media for E. invadens. A substitute of serum, PACSR has been described as an alternative for growth of E. histolytica and also maintains growth of E. invadens. When PACSR was used instead of serum for encystation of E. invadens the efficiency was the same as for serum. Our present data show that PACSR can support the growth and induction of encystation of E. invadens strain IP-1.

HIV causes progressive impairment of the cellular immune system leading to increased susceptibility to infectious agents. Parasitic infestations are common in HIV-infected patients and usually lead to diarrhoea. Few studies have addressed the issue of intestinal parasites among HIV-infected persons in Cameroon. This investigation was conducted in Douala, Cameroon, to assess the prevalence of gastrointestinal parasites in HIV-infected patients, taking into account their immune status and treatment course. Stool and blood samples were collected from 201 HIV-positive patients for the investigation of intestinal pathogens and CD4+ counts. Fifty-six (27.9%) patients harbored pathogens. The most frequent pathogens were Candida spp. (14.9%), Cryptosporidium spp. (7.5%), Entamoeba histolytica, and Entamoeba dispar (3%). The presence of pathogens was significantly associated with diarrhoea, as they were found in 48.6% of diarrhoeic stools and 23.2% of non-diarrhoeic stools (OR = 3.14, p= 0.0...

The aim and the background of this paper was to investigate how ancient primitive eukaryotes evolved to the successful parasites they are today. In preparing this work, the most significant literature of the last years has been studied. We expand it by the results of our own research. Results and conclusion: Anaerobic single-celled eukaryotes, such as
Entamoeba invadens and Giardia lamblia , became successful invasive pathogens by using mechanisms inherited from the common ancestor (LECA). As described in previous papers pathogen protists have a surprising stem cell network (ancient
protolineage) controlled by intrinsic and extrinsic mechanisms of cell conversion and differentiation inherited from the ancestor. Mechanisms leading to pathogenicity were not acquired after the organisms became parasitic, they were present before the single-celled organisms switched to parasitism. Only organisms possessing an extended ancestral stem cell system capable of switching between most oxidative
(MO) and most hypoxic (MH) niches by changing metabolic pathways and antigenicity could develop into successful invasive pathogens like Entamoeba or Giardia. Related organisms not conserving all ancestral features evolved to become luminal commensals or free-living protists

Background Six species of the genus Entamoeba, i.e., E. histolytica, E. dispar, E. moshkovskii, E. polecki, E. coli, and E. hartmanii can be found in human stools. Among these, only E. histolytica is considered to be pathogenic, causing intestinal and extra-intestinal disease, but it is morphologically identical to E. dispar and E. moshkovskii. In general, E. polecki, E. coli, and E. hartmanii can be differentiated morphologically from E. histolytica, but some of their diagnostic morphologic features may overlap creating issues for the differential diagnosis. Moreover, the previous inability to differentiate among Entamoeba species has limited epidemiologic information on E histolytica. The objective of this study was to develop a rapid, high-throughput screening method using Luminex technique for the simultaneous detection and differentiation of Entamoeba species. Methods PCR amplification was performed with biotinylated Entamoeba sp 18S rRNA gene primers, designed to amplify a fra...

Background: In this study, a total of 426 human faecal samples were examined for the presence of Entamoeba histolytica, Entamoeba dispar, Entamoeba moshkovskii infection via a combination of microscopic examination and nested polymerase chain reaction (PCR) targeting 16S ribosomal RNA of Entamoeba species.

Methods: Faecal sample were collected from 426 participants in five rural villages in Peninsular Malaysia. The faecal samples were processed by direct wet smear and formalin ethyl acetate concentration technique followed by iodine staining and examined via microscopy for the presence of Entamoeba species and other intestinal parasites. Microscopically positive samples for Entamoeba species cysts were further characterized using a Nested Polymerase Chain Reaction (Nested-PCR) targeting 16S-like ribosomal RNA gene. The data entry and analysis was carried out using the SPSS software (Statistical Package for the Social Sciences) program for Windows version 17 (SPSS, Chicago, IL, USA).

Results: Based on single faecal examination, overall prevalence of Entamoeba infection was 17.6% (75/426). Females (19.1%) were more commonly infected compared to males (15.9%). Comparison by age groups showed that adults (23.9%) had higher infection rates than children (15.3%). The PCR results showed that 52 out of 75 microscopy positive samples successfully generated species-specific amplicons. The infection with E. histolytica (75.0%; 39/52) was the most common, followed by E. dispar (30.8%; 18/52) and E. moshkovskii (5.8%; 3/52). Of these, 33 (63.5%) were shown to contain only E. histolytica, 10 (19.2%) contained E. dispar and 3 (5.8%) contained only E. moshkovskii. Mixed infection with E. histolytica and E. dispar was found in 6 (11.5%) samples.

The present study essentially emphasized the benefit of molecular techniques in discriminating the
pathogenic Entamoeba species from the non-pathogenic for accurate diagnosis and better management of amoebiasis.
The presence of E. moshkovskii is of great public health concern as it was the first time it has been reported in Malaysia.