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an integrated microfluidic device for rapid serodiagnosis of amebiasis.a microfluidic device was successfully fabricated for the rapid serodiagnosis of amebiasis. a micro bead-based immunoassay was fabricated within integrated microfluidic chip to detect the antibody to entamoeba histolytica in serum samples. in this assay, a recombinant fragment of c terminus of intermediate subunit of galactose and n-acetyl-d-galactosamine-inhibitable lectin of entamoeba histolytica (c-igl, aa 603-1088) has been utilized instead of the crude antigen. this device was validated wit ...201324403984
snap-tag technology optimized for use in entamoeba histolytica.entamoeba histolytica is a protozoan parasite responsible for invasive intestinal and extraintestinal amebiasis. the pathology of amebiasis is still poorly understood, which can be largely attributed to lack of molecular tools. here we present the optimization of snap-tag technology via codon optimization specific for e. histolytica. the resultant snap protein is highly expressed in amebic trophozoites, and shows proper localization when tagged with an endoplasmic reticulum retention signal. we ...201324391864
identification of the virulence landscape essential for entamoeba histolytica invasion of the human colon.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 ar ...201324385905
species-specific immunity induced by infection with entamoeba histolytica and entamoeba moshkovskii in mice.entamoeba histolytica, the parasitic amoeba responsible for amoebiasis, causes approximately 100,000 deaths every year. there is currently no vaccine against this parasite. we have previously shown that intracecal inoculation of e. histolytica trophozoites leads to chronic and non-healing cecitis in mice. entamoeba moshkovskii, a closely related amoeba, also causes diarrhea and other intestinal disorders in this model. here, we investigated the effect of infection followed by drug-cure of these ...201324312397
globalised world, globalised diseases: a case report on an amoebiasis-associated colon perforation.in 2010 the world health organisation estimated the number of infections with entamoeba histolytica at about 50 million cases including 100000 fatal courses. in most cases this infection is a subclinical event with few or none symptoms noticeable for the patient. courses of this disease and incidence of this parasite in industrialised nations are not yet fully investigated. our case reports about a 68-year-old male patient from turkey who lives for more than 30 years in germany and had not been ...201324303471
monocyte locomotion inhibitory factor produced by e. histolytica improves motor recovery and develops neuroprotection after traumatic injury to the spinal cord.monocyte locomotion inhibitory factor (mlif) is a pentapeptide produced by entamoeba histolytica that has a potent anti-inflammatory effect. either mlif or phosphate buffered saline (pbs) was administered directly onto the spinal cord (sc) immediately after injury. motor recovery was evaluated. we also analyzed neuroprotection by quantifying the number of surviving ventral horn motor neurons and the persistence of rubrospinal tract neurons. to evaluate the mechanism through which mlif improved t ...201324294606
synthesis, characterization, and anti-amoebic activity of n-(pyrimidin-2-yl)benzenesulfonamide derivatives.a new series of n-(pyrimidin-2-yl)benzenesulfonamide derivatives, 3a-3i and 4a-4i, was synthesized from pyrimidin-2-amines, 2a-2i, with the aim to explore their effects on in vitro growth of entamoeba histolytica. the chemical structures of the compounds were elucidated by elemental analysis, ft-ir, (1) h- and (13) c-nmr, and esi mass-spectral data. in vitro anti-amoebic activity was evaluated against hm1 : imss strain of entamoeba histolytica. the ic50 values were calculated by using the double ...201324327446
synthesis and antiprotozoal activity of nitazoxanide-n-methylbenzimidazole hybrids.a series of a novel hybrid compounds between nitazoxanide and n-methylbenzimidazole were synthesized starting from the corresponding n-methyl-2-nitroanilines. the new hybrid compounds (1-13) were evaluated in vitro against giardia intestinalis, entamoeba histolytica, trichomonas vaginalis. ntz, mtz and abz were used as drug standards. experimental evaluations revealed all of the new compounds (1-13) were active and showed strong activity against the three protozoa, particularly with e. histolyti ...201324183540
the expanding superfamily of gelsolin homology domain proteins.the gelsolin homology (gh) domain has been found to date exclusively in actin-binding proteins. in humans, three copies of the domain are present in capg, five copies in supervillin, and six copies each in adseverin, gelsolin, flightless i and the villins: villin, advillin and villin-like protein. caenorhabditis elegans contains a four-gh-domain protein, gsnl-1. these architectures are predicted to have arisen from gene triplication followed by gene duplication to result in the six-domain protei ...201324155256
analysis of the protein phosphotome of entamoeba histolytica reveals an intricate phosphorylation network.phosphorylation is the most common mechanism for the propagation of intracellular signals. protein phosphatases and protein kinases play a dynamic antagonistic role in protein phosphorylation. protein phosphatases make up a significant fraction of eukaryotic proteome. in this article, we report the identification and analysis of protein phosphatases in the intracellular parasite entamoeba histolytica. based on an in silico analysis, we classified 250 non-redundant protein phosphatases in e. hist ...201324236039
synthesis and in vitro evaluation of new ethyl and methyl quinoxaline-7-carboxylate 1,4-di-n-oxide against entamoeba histolytica.in our search for new antiamoebic agents, a new series of ethyl and methyl quinoxaline-7-carboxylate 1,4-di-n-oxide derivatives have been synthesized using the beirut reaction. all compounds were characterized by spectroscopic techniques and elemental analysis. antiamoebic activity was evaluated in vitro against entamoeba histolytica strain hm1:imss by the microdilution method, and the structure-activity relationship was analyzed. we found that eleven quinoxaline derivatives showed greater activ ...201323787289
identification and analysis of putative homologues of mechanosensitive channels in pathogenic protozoa.mechanosensitive channels play important roles in the physiology of many organisms, and their dysfunction can affect cell survival. this suggests that they might be therapeutic targets in pathogenic organisms. pathogenic protozoa lead to diseases such as malaria, dysentery, leishmaniasis and trypanosomiasis that are responsible for millions of deaths each year worldwide. we analyzed the genomes of pathogenic protozoa and show the existence within them of genes encoding putative homologues of mec ...201323785469
functional manipulation of a calcium-binding protein from entamoeba histolytica guided by paramagnetic nmr.ehcabp1, one of the calcium-binding proteins from entamoeba histolytica, is a two-domain ef-hand protein. the two domains of ehcabp1 are structurally and functionally different from each other. however, both domains are required for structural stability and a full range of functional diversity. analysis of sequence and structure of ehcabp1 and other cabps indicates that the c-terminal domain of ehcabp1 possesses a unique structure compared with other family members. this had been attributed to t ...201323782698
determination of an unstable pentapeptide, monocyte locomotion inhibitory factor, in dog blood by lc-ms/ms: application to a pharmacokinetic study.a liquid chromatography-tandem mass spectrometry (lc-ms/ms) method has been developed and established for the quantitative determination of monocyte locomotion inhibitory factor, a pentapeptide (met-gln-cys-asn-ser) produced by entamoeba histolytica in axenic culture, in dog blood. the main challenge was the chemical and enzymatic instability of the peptide which was successfully overcome. after a simple protein precipitation, mlif was separated from as-5 (met-gln-gly-asn-ser), acted as an inter ...201323777619
comparison of clinical and laboratory characteristics of intestinal amebiasis with shigellosis among patients visiting a large urban diarrheal disease hospital in bangladesh.between 1993 and 2011, a total of 371 intestinal amebiasis (ia), caused by entamoeba histolytica cases were compared with 1,113 shigellosis (randomly selected) patients of icddr,b, excluding co-infections (rotavirus and vibrio cholerae) in two age stratums: 0-14 years of age and ≥ 15 years of age. the number of ia and shigellosis cases gradually reduced over the study period. in multivariate analysis, individuals 0-14 years of age, slum dwellers (odds ratio [or] 3.51; 95% confidence interval [ci ...201323775017
the ehcpadh112 complex of entamoeba histolytica interacts with tight junction proteins occludin and claudin-1 to produce epithelial damage.entamoeba histolytica, the protozoan responsible for human amoebiasis, causes between 30,000 and 100,000 deaths per year worldwide. amoebiasis is characterized by intestinal epithelial damage provoking severe diarrhea. however, the molecular mechanisms by which this protozoan causes epithelial damage are poorly understood. here, we studied the initial molecular interactions between the e. histolytica ehcpadh112 virulence complex and epithelial mdck and caco-2 cells. by confocal microscopy, we di ...201323762290
chemo-informatic design of antibiotic geldenamycin analogs to target stress proteins hsp90 of pathogenic protozoan parasites.stress proteins hsp90 (heat shock proteins) are essential molecular chaperones involved in signal transduction, cell cycle control, stress management, folding and degradation of proteins. hsp90 have been found in a variety of organisms including pathogens suggesting that they are ancient and conserved proteins. here, using molecular modeling and docking protocols, antibiotic geldenamycin and its analog are targeted to the hsp90 homolog proteins of pathogenic protozoans plasmodium falciparum, lei ...201323750075
molecular basis of ligand recognition by oass from e. histolytica: insights from structural and molecular dynamics simulation studies.o-acetyl serine sulfhydrylase (oass) is a pyridoxal phosphate (plp) dependent enzyme catalyzing the last step of the cysteine biosynthetic pathway. here we analyze and investigate the factors responsible for recognition and different conformational changes accompanying the binding of various ligands to oass.201323747298
high occurrence of entamoeba histolytica in the municipalities of ariquemes and monte negro, state of rondônia, western amazonia, brazil.entamoeba histolytica infections were investigated in residents of the ariquemes and monte negro municipalities in rondônia state, brazil.201323740019
synthesis and antiprotozoal activity of novel 2-{[2-(1h-imidazol-1-yl)ethyl]sulfanyl}-1h-benzimidazole derivatives.a series of 19 new 2-{[2-(1h-imidazol-1-yl)ethyl]sulfanyl}-1h-benzimidazole derivatives was synthesized starting from the properly substituted 1,2-phenylendiamine. these compounds have hydrogen or methyl at position 1; while hydrogen, chlorine, ethoxy or methoxycarbonyl group is at position 5 and/or 6. the novel compounds were tested against protozoa trichomonas vaginalis, giardia intestinalis and entamoeba histolytica. experimental evaluations revealed strong activity for all tested compounds, ...201323731944
sialic acid-dependent attachment of mucins from three mouse strains to entamoeba histolytica.mouse strain-specific differences in the carbohydrate composition of intestinal mucins were hypothesized to account for strain-dependent susceptibility to entamoeba histolytica. to test this hypothesis, intestinal mucins from susceptible and resistant inbred strains of mice were analyzed for their o-glycan content and for their ability to inhibit amoebic adherence to (galnac)12-27-hsa neo-glycoproteins. the results showed that the colorectal mucin o-glycan of susceptible cba mice was lower in si ...201323726913
seroprevalence of entamoeba histolytica infection among chinese men who have sex with men.men who have sex with men (msm) were found to be one of the high-risk populations for entamoeba histolytica (e. histolytica) infection. accompanied by the prevalence of human immunodeficiency virus (hiv) among msm, invasive amebiasis caused by e. histolytica has been paid attention to as an opportunistic parasitic infection. however, the status of e. histolytica infection among msm has been barely studied in mainland china.201323717699
entamoeba histolytica antigenic protein detected in pus aspirates from patients with amoebic liver abscess.entamoeba histolytica is a causative agent of amoebic liver abscess (ala) and is endemic in many underdeveloped countries. we investigated antigenic e. histolytica proteins in liver abscess aspirates using proteomics approach. pus samples were first tested by real-time pcr to confirm the presence of e. histolytica dna and the corresponding serum samples tested for e. histolytica-specific igg by a commercial elisa. proteins were extracted from three and one pool(s) of pus samples from ala and pla ...201323680184
prevalence of intestinal protozoa in communities along the lake victoria region of uganda.the objective of this study was to assess water-borne parasite point prevalence in communities in close proximity to lake victoria in uganda prior to the implementation of a clean water intervention, and to investigate possible associations of water source and latrine access with protozoan prevalence. utilizing a rapid antigen test, parasite prevalence for giardia lamblia and entamoeba histolytica/dispar was determined from stool samples of individuals living in six ugandan communities. stool sa ...201323642567
worldwide genealogy of entamoeba histolytica: an overview to understand haplotype distribution and infection outcome.although entamoeba histolytica is one of the most prevalent intestinal parasites, how the different strains of this species are distributed all over the world and how different genotypes are associated with the infection outcome are yet to be fully understood. recently, the use of a number of molecular markers has made the characterization of several genotypes in those regions with high incidence of amoebiasis possible. this work proposes the first genealogy of e. histolytica, with an haplotype ...201323624203
primary pathogenicity analysis of a chinese entamoeba histolytica isolate.this study is the first to isolate an entamoeba histolytica strain from chinese amoebic patients and to conduct a detailed examination of its virulence. a fecal sample that contains cysts of e. histolytica was obtained from guangxi province. the sample was cultured axenically and then cloned by limiting dilution, and named as xlac. in vitro and in vivo tests were conducted to evaluate the virulence of the entamoeba isolate. the e. histolytica strain xlac was successfully cloned and cultured axen ...201323612076
synthesis and evaluation of 7-chloro-4-(piperazin-1-yl)quinoline-sulfonamide as hybrid antiprotozoal agents.a new series of 4-aminochloroquinoline based sulfonamides were synthesized and evaluated for antiamoebic and antimalarial activities. out of the eleven compounds evaluated (f1-f11), two of them (f3 and f10) showed good activity against entamoeba histolytica (ic50 <5 μm). three of the compounds (f5, f7 and f8) also displayed antimalarial activity against the chloroquine-resistant (fcr-3) strain of plasmodium falciparum with ic50 values of 2 μm. compound f7, whose crystal structure was also determ ...201323602620
entamoeba histolytica. 201323589427
unexpected properties of nadp-dependent secondary alcohol dehydrogenase (adh-1) in trichomonas vaginalis and other microaerophilic parasites.our previous observation that nadp-dependent secondary alcohol dehydrogenase (adh-1) is down-regulated in metronidazole-resistant trichomonas vaginalis isolates prompted us to further characterise the enzyme. in addition to its canonical enzyme activity as a secondary alcohol dehydrogenase, a pronounced, so far unknown, background nadph-oxidising activity in absence of any added substrate was observed when the recombinant enzyme or t. vaginalis extract were used. this activity was strongly enhan ...201323578856
polyunsaturated fatty acids induce polarized submembranous f-actin aggregates and kill entamoeba histolytica.we have recently identified a novel galacto-glycerolipid (ggl) from the plant oxalis corniculata that killed the human pathogen entamoeba histolytica. in this study, we show that the anti-amoebic activity of ggl was due to the polyunsaturated fatty acid α-linolenic acid (c18:3 ) side chain. treatment of α-linolenic acid to e. histolytica trophozoites disrupted the cytoskeletal network and led to polarization of f-actin at one end of the cells with prominent filopodial extensions. in addition, cl ...201323568815
site-specific o-glycosylation on the muc2 mucin protein inhibits cleavage by the porphyromonas gingivalis secreted cysteine protease (rgpb).the colonic epithelial surface is protected by an inner mucus layer that the commensal microflora cannot penetrate. we previously demonstrated that entamoeba histolytica secretes a protease capable of dissolving this layer that is required for parasite penetration. here, we asked whether there are bacteria that can secrete similar proteases. we screened bacterial culture supernatants for such activity using recombinant fragments of the muc2 mucin, the major structural component, and the only gel ...201323546879
localization of phosphatidylinositol 4,5-bisphosphate to lipid rafts and uroids in the human protozoan parasite entamoeba histolytica.entamoeba histolytica is an intestinal protozoan parasite and is the causative agent of amoebiasis. during invasive infection, highly motile amoebae destroy the colonic epithelium, enter the blood circulation, and disseminate to other organs such as liver, causing liver abscess. motility is a key factor in e. histolytica pathogenesis, and this process relies on a dynamic actomyosin cytoskeleton. in other systems, phosphatidylinositol 4,5-bisphosphate [pi(4,5)p2] is known to regulate a wide varie ...201323545298
infection-induced anaemia: a cross-sectional study of 14,636 german travellers aged 20-49 years.anaemia is a frequently diagnosed condition which can develop as a consequence of numerous factors, including infectious diseases (ids). travelling, especially in sub-/tropical regions, leads to an elevated risk of contracting ids. the aim of our study was to assess the epidemiological significance of ids in inducing anaemia among a large cohort of returned travellers.201324014235
entamoeba histolytica p-glycoprotein (ehpgp) inhibition, induce trophozoite acidification and enhance programmed cell death.programmed cell death (pcd) is induced in entamoeba histolytica by a variety of stimuli in vitro and in vivo. in mammals, intracellular acidification serves as a global switch for inactivating cellular processes and initiates molecular mechanisms implicated in the destruction of the genome. in contrast, intracellular alkalinization produced by p-glycoprotein overexpression in multidrug-resistant cells has been related to apoptosis resistance. our previous studies showed that overexpression of e. ...201324012862
immunogenicity and protective efficacy of heparan sulphate binding proteins of entamoeba histolytica in a guinea pig model of intestinal amoebiasis.entamoeba histolytica infection is associated with considerable morbidity and mortality in the form of intestinal and extraintestinal amoebiasis. no vaccine is yet available for amoebiasis. heparan sulphate binding proteins (hsbps) from e. histolytica were evaluated for immunogenicity and protective efficacy in a guinea pig model. animals were immunized subcutaneously with 30μg of hsbp by three weekly inoculations. the immunogenicity of hsbp was determined by antibody response (igg, igm and iga) ...201324007700
molecular basis for benzimidazole resistance from a novel β-tubulin binding site model.benzimidazole-2-carbamate derivatives (bzcs) are the most commonly used antiparasitic drugs for the treatment of protozoan and helminthic infections. bzcs inhibit the microtubule polymerization mechanism through binding selectively to the β-tubulin subunit in which mutations have been identified that lead to drug resistance. currently, the lack of crystallographic structures of β-tubulin in parasites has limited the study of the binding site and the analysis of the resistance to bzcs. recently, ...201323995453
effect of the sesquiterpene lactone incomptine a in the energy metabolism of entamoeba histolytica.entamoeba histolytica is the causative agent of human amoebiasis, which mainly affects developing countries. although several drugs are effective against e. histolytica trophozoites, the control of amoebiasis requires the development of new and better alternative therapies. medicinal plants have been the source of new molecules with remarkable antiprotozoal activity. incomptine a isolated from decachaeta incompta leaves, is a sesquiterpene lactone of the heliangolide type which has the major in ...201323994114
amoebic dysentery.amoebic dysentery is caused by the protozoan parasite entamoeba histolytica. it is transmitted in areas where poor sanitation allows contamination of drinking water and food with faeces. in these areas, up to 40% of people with diarrhoea may have amoebic dysentery.201323991750
high prevalence of diarrhoegenic intestinal parasite infections among non-art hiv patients in fitche hospital, ethiopia.hiv infection has been modifying both the epidemiology and outcome of parasite infections. hence, this study was undertaken to determine the prevalence of cryptosporidium and other intestinal parasite infections among hiv positives with and without antiretroviral treatment(art) and its association with cd4+ t-cell count.201323991132
effect of the silencing of the ehcp112 gene on the in vitro virulence of entamoeba histolytica.entamoeba histolytica is an intestinal protozoan parasite that causes amoebiasis in humans, affecting up to 50 million people worldwide each year and causing 40,000 to 100,000 deaths annually. ehcp112 is a cysteine proteinase of e. histolytica able to disrupt cell monolayers and digest extracellular matrix proteins, it is secreted by trophozoites and it can be active in a wide range of temperature and ph. these characteristics have encouraged the use of ehcp112 in the design and production of po ...201323981435
evidence for a bacterial lipopolysaccharide-recognizing g-protein-coupled receptor in the bacterial engulfment by entamoeba histolytica.entamoeba histolytica is the causative agent of amoebic dysentery, a worldwide protozoal disease that results in approximately 100,000 deaths annually. the virulence of e. histolytica may be due to interactions with the host bacterial flora, whereby trophozoites engulf colonic bacteria as a nutrient source. the engulfment process depends on trophozoite recognition of bacterial epitopes that activate phagocytosis pathways. e. histolytica gpcr-1 (ehgpcr-1) was previously recognized as a putative g ...201323975887
current laboratory diagnosis of opportunistic enteric parasites in human immunodeficiency virus-infected patients.diarrhea is a major cause of morbidity and mortality in human immunodeficiency virus (hiv)-infected individuals. opportunistic enteric parasitic infections are encountered in 30-60% of hiv seropositive patients in developed countries and in 90% of patients in developing countries. once the cd4(+) cell count drops below 200 cells/μl, patients are considered to have developed acquired immunodeficiency syndrome (aids), with the risk of an aids-defining illness or opportunistic infection significant ...201323961436
efficacies of two in-house indirect elisas for diagnosis of amoebic liver abscess.entamoeba histolytica causes amoebic diarrhoea, colitis and liver abscess (ala). diagnosis of ala is difficult, as most patients do not have simultaneous intestinal amoebic infection. at hospital universiti sains malaysia (husm), diagnosis of ala relies on a combination of clinical findings, ultrasound examination of the liver and serodiagnosis using a commercial kit. in this study, two in-house indirect elisas were developed and evaluated. one of the in-house assays utilises e. histolytica crud ...201323959490
imported amoebic liver abscess in france.worldwide, amoebic liver abscess (ala) can be found in individuals in non-endemic areas, especially in foreign-born travelers.201323951372
robust gene silencing mediated by antisense small rnas in the pathogenic protist entamoeba histolytica.rna interference uses small rnas (srna), which target genes for sequence-specific silencing. the parasite entamoeba histolytica contains an abundant repertoire of 27 nt antisense (as) srna with 5'-polyphosphate termini, but their roles in regulating gene expression have not been well established. we demonstrate that a gene-coding region to which large numbers of as srnas map can serve as a 'trigger' and silence the gene fused to it. silencing is mediated by generation of as srnas with 5'-polypho ...201323935116
the genome and transcriptome of the enteric parasite entamoeba invadens, a model for encystation.several eukaryotic parasites form cysts that transmit infection. the process is found in diverse organisms such as toxoplasma, giardia, and nematodes. in entamoeba histolytica this process cannot be induced in vitro, making it difficult to study. in entamoeba invadens, stage conversion can be induced, but its utility as a model system to study developmental biology has been limited by a lack of genomic resources. we carried out genome and transcriptome sequencing of e. invadens to identify molec ...201323889909
identification and characterization of micrornas from entamoeba histolytica hm1-imss.entamoeba histolytica is the causative agent of amebiasis, a disease that is a major source of morbidity and mortality in the developing world. micrornas (mirnas) are a large group of non-coding rnas that play important roles in regulating gene expression and protein translation in animals. genome-wide identification of mirnas is a critical step to facilitating our understanding of genome organization, genome biology, evolution, and post-transcriptional regulation.201323874540
investigation of intestinal parasites in dialysis patients.to search for the opportunistic and other pathogenic intestinal parasites in dialysis patients, and to compare the methods used for diagnosis.201323860891
cytokine and chemokine responses to helminth and protozoan parasites and to fungus and mite allergens in neonates, children, adults, and the elderly.in rural sub-saharan africa, endemic populations are often infected concurrently with several intestinal and intravascular helminth and protozoan parasites. a specific, balanced and, to an extent, protective immunity will develop over time in response to repeated parasite encounters, with immune responses initially being poorly adapted and non-protective. the cellular production of pro-inflammatory and regulatory cytokines and chemokines in response to helminth, protozoan antigens and ubiquitous ...201323855879
the calcium binding protein ehcabp6 is a microtubular-end binding protein in entamoeba histolytica.the genome of entamoeba histolytica encodes several calcium binding proteins and those characterized thus far have been shown to participate predominantly in phagocytosis and endocytosis. our study showed that ehcabp6 has two ef-hand domains efi and efiii; it can bind ca(2+) in vitro and undergoes conformational transition on binding ca(2+) suggesting that it can serve as a calcium signal sensor. ehcabp6 is localized in the nucleus, cytoplasm and plasma membrane and is sensitive to heat stress. ...201323848346
the 25 kda subunit of cleavage factor im is a rna-binding protein that interacts with the poly(a) polymerase in entamoeba histolytica.in eukaryotes, polyadenylation of pre-mrna 3' end is essential for mrna export, stability and translation. taking advantage of the knowledge of genomic sequences of entamoeba histolytica, the protozoan responsible for human amoebiasis, we previously reported the putative polyadenylation machinery of this parasite. here, we focused on the predicted protein that has the molecular features of the 25 kda subunit of the cleavage factor im (cfim25) from other organisms, including the nudix (nucleoside ...201323840799
entamoeba histolytica brain abscess.brain abscess due to entamoeba histolytica is most commonly seen in a small percentage of patients who also have an amebic liver abscess. the typical patient is a young man who after treatment for liver abscess with apparent improvement develops symptoms and signs of central nervous system involvement. the average age of the patient is 30 years, and common presentations include headache, vomiting, and altered mental status. signs of amebic brain abscess include most commonly meningeal signs, fac ...201323829905
overexpression of specific cysteine peptidases confers pathogenicity to a nonpathogenic entamoeba histolytica clone.cysteine peptidases (cps) of entamoeba histolytica are considered to be important pathogenicity factors. previous studies have found that under standard axenic culture conditions, only four (ehcp-a1, ehcp-a2, ehcp-a5, and ehcp-a7) out of 35 papain-like ehcp genes present in the e. histolytica genome are expressed at high levels. little is known about the expression of cps in e. histolytica during amoebic liver abscess (ala) formation. in the current study, a quantitative real-time pcr assay was ...201323532975
metastatic abscess formation in a preexisting chest wall tumor: a rare initial presentation of klebsiella pneumoniae liver abscess.the common infectious agents in the chest wall include mycobacterium tuberculosis, actinomyces, fungi, nocardia, entamoeba histolytica, and other aerobes and anaerobes. klebsiella pneumoniae is an uncommon etiological agent. we describe a case of ankylosing spondylitis in a 45-year-old man, who had exhibited a painless lump in the left posterior chest wall for 3 months and who presented with acute-onset pain, erythematous change, and fever in the 2 weeks before admission. cultures of the blood a ...201323526295
g protein signaling in the parasite entamoeba histolytica.the parasite entamoeba histolytica causes amebic colitis and systemic amebiasis. among the known amebic factors contributing to pathogenesis are signaling pathways involving heterotrimeric and ras superfamily g proteins. here, we review the current knowledge of the roles of heterotrimeric g protein subunits, ras, rho and rab gtpase families in e. histolytica pathogenesis, as well as of their downstream signaling effectors and nucleotide cycle regulators. heterotrimeric g protein signaling likely ...201323519208
evaluation of entamoeba histolytica recombinant phosphoglucomutase protein for serodiagnosis of amoebic liver abscess.amoebic liver abscess (ala) is the most frequent clinical presentation of extra-intestinal amoebiasis. the diagnosis of ala is typically based on the developing clinical symptoms, characteristic changes on radiological imaging and serology. numerous serological tests have been introduced for the diagnosis of ala, either detecting circulating amoebic antigens or antibodies. however those tests show some pitfalls in their efficacy and/or the preparation of the tests are costly and tedious. the com ...201323514636
cysteine protease-binding protein family 6 mediates the trafficking of amylases to phagosomes in the enteric protozoan entamoeba histolytica.phagocytosis plays a pivotal role in nutrient acquisition and evasion from the host defense systems in entamoeba histolytica, the intestinal protozoan parasite that causes amoebiasis. we previously reported that e. histolytica possesses a unique class of a hydrolase receptor family, designated the cysteine protease-binding protein family (cpbf), that is involved in trafficking of hydrolases to lysosomes and phagosomes, and we have also reported that cpbf1 and cpbf8 bind to cysteine proteases or ...201323509141
silencing of entamoeba histolytica glucosamine 6-phosphate isomerase by rna interference inhibits the formation of cyst-like structures.encystment is an essential process in the biological cycle of the human parasite entamoeba histolytica. in the present study, we evaluated the participation of e. histolytica gln6pi in the formation of amoeba cyst-like structures by rna interference assay. amoeba trophozoites transfected with two gln6pi sirnas reduced the expression of the enzyme in 85%, which was confirmed by western blot using an anti-gln6pi antibody. the e. histolytica gln6pi knockdown with the mix of both sirnas resulted in ...201323484154
proteases from entamoeba spp. and pathogenic free-living amoebae as virulence factors.the standard reference for pathogenic and nonpathogenic amoebae is the human parasite entamoeba histolytica; a direct correlation between virulence and protease expression has been demonstrated for this amoeba. traditionally, proteases are considered virulence factors, including those that produce cytopathic effects in the host or that have been implicated in manipulating the immune response. here, we expand the scope to other amoebae, including less-pathogenic entamoeba species and highly patho ...201323476670
entamoeba histolytica induces cell death of ht29 colonic epithelial cells via nox1-derived ros.entamoeba histolytica, which causes amoebic colitis and occasionally liver abscess in humans, is able to induce host cell death. however, signaling mechanisms of colon cell death induced by e. histolytica are not fully elucidated. in this study, we investigated the signaling role of nox in cell death of ht29 colonic epithelial cells induced by e. histolytica. incubation of ht29 cells with amoebic trophozoites resulted in dna fragmentation that is a hallmark of apoptotic cell death. in addition, ...201323467460
false-negative serologies in amebic liver abscess: report of two cases.amebiasis, the parasitic disease caused by entamoeba histolytica, may result in extra-intestinal diseases among which liver abscess is the most common manifestation. we report two cases of amebic liver abscess illustrating the inequal sensitivity of serologic tests detecting anti-amebic antibodies.201323464723
resolution of refractory thrombotic thrombocytopenic purpura (ttp) after successful treatment of a fulminant colitis due to entamoeba histolytica. 201323453561
acute amoebic appendicitis: case reports and review of parasitic appendicitis.amoebic appendicitis is very rare, occurring in about 0.5% to 2% of acute appendicitis, and usually not reported in children. we report a case of confirmed acute amoebic appendicitis complicating amoebic colitis in a 7-year-old pakistani boy living in southern jeddah, saudi arabia, and briefly review the literature on parasitic appendicitis.201326619448
single residue mutation in active site of serine acetyltransferase isoform 3 from entamoeba histolytica assists in partial regaining of feedback inhibition by cysteine.the cysteine biosynthetic pathway is essential for survival of the protist pathogen entamoeba histolytica, and functions by producing cysteine for countering oxidative attack during infection in human hosts. serine acetyltransferase (sat) and o-acetylserine sulfhydrylase (oass) are involved in cysteine biosynthesis and are present in three isoforms each. while ehsat1 and ehsat2 are feedback inhibited by end product cysteine, ehsat3 is nearly insensitive to such inhibition. the active site residu ...201323437075
effect of the leptin receptor q223r polymorphism on the host transcriptome following infection with entamoeba histolytica.resistance to amebiasis is associated with a polymorphism in the leptin receptor. previous studies demonstrated that humans with the ancestral q223 leptin receptor allele were nearly four times less likely to be infected with entamoeba histolytica than those carrying the mutant r223 allele. we hypothesized that the q223 allele protected against e. histolytica via stat3-mediated transcription of genes required for mucosal immunity. to test this, mice containing the humanized lepr q or r allele at ...201323429533
testosterone increases susceptibility to amebic liver abscess in mice and mediates inhibition of ifnγ secretion in natural killer t cells.amebic liver abscess (ala), a parasitic disease due to infection with the protozoan entamoeba histolytica, occurs age and gender dependent with strong preferences for adult males. using a mouse model for ala with a similar male bias for the disease, we have investigated the role of female and male sexual hormones and provide evidence for a strong contribution of testosterone. removal of testosterone by orchiectomy significantly reduced sizes of abscesses in male mice, while substitution of testo ...201323424637
the small gtpase ehrabb of entamoeba histolytica is differentially expressed during phagocytosis.it has been described that the pathogenicity of entamoeba histolytica is influenced by environmental conditions and that transcription profile changes occur during invasion, suggesting that gene expression may be involved in the virulence of this parasite. however, the molecular mechanisms that are implicated in the control of gene expression in this microorganism are poorly understood. here, we showed that the expression of the ehrabb protein, a small gtpase involved in phagocytosis, is modifie ...201323400794
entamoeba histolytica: identification of thioredoxin-targeted proteins and analysis of serine acetyltransferase-1 as a prototype example.entamoeba histolytica, the causative agent of amoebiasis, possesses the dithiol-containing redox proteins trx (thioredoxin) and trxr (trx reductase). both proteins were found to be covalently modified and inactivated by metronidazole, a 5-nitroimidazole drug that is commonly used to treat infections with microaerophilic protozoan parasites in humans. currently, very little is known about enzymes and other proteins participating in the trx-dependent redox network of the parasite that could be ind ...201323398389
[investigation of norovirus infection incidence among 0-5 years old children with acute gastroenteritis admitted to two different hospitals in ankara, turkey].norovirus causes severe gastroenteritis requiring hospitalization especially in children less than five years of age both in developed and developing countries. therefore, we aimed to investigate the incidence of norovirus (nov) in 0-5 years old children with acute gastroenteritis in two large hospitals in ankara, turkey. stool samples were obtained from 1000 (413 female, 587 male) children between 0-5 years old with acute gastroenteritis who attended to the department of paediatrics, ministry o ...201323390907
the α-helical regions of kerp1 are important in entamoeba histolytica adherence to human cells.the lysine and glutamic acid rich protein kerp1 is a unique surface adhesion factor associated with virulence in the human pathogen entamoeba histolytica. both the function and structure of this protein remain unknown to this date. here, we used circular dichroism, analytical ultracentrifugation and bioinformatics modeling to characterize the structure of kerp1. our findings revealed that it is an α-helical rich protein organized as a trimer, endowed with a very high thermal stability (tm = 89.6 ...201323378906
evaluation of formalin-ether sedimentation and trichrome staining techniques: its effectiveness in detecting entamoeba histolytica/dispar/moshkovskii in stool samples.this study was conducted to evaluate two routinely microscopic diagnostic methods in comparison with single-round pcr assay as the reference technique to detect entamoeba histolytica/dispar/moshkovskii. examination was performed on 500 stool samples obtained from orang asli communities in different states of malaysia using formalin-ether sedimentation, trichrome staining and single-round pcr techniques. ninety-three stool samples were detected e. histolytica/dispar/moshkovskii positive by routin ...201323361047
entamoeba histolytica exacerbates epithelial tight junction permeability and proinflammatory responses in muc2(-/-) mice.human mucin-2 (muc-2) is the first line of innate host defense in preventing pathogen-induced epithelial injury. entamoeba histolytica (eh) colonizes the mucus layer by binding of the parasite's surface galactose lectin to galactose and n-acetyl-d-galactosamine residues on colonic muc-2, preventing parasite contact-dependent cytolysis of epithelial cells. we quantified early innate responses to eh in wild-type and muc-2-deficient mice (muc2(-/-)) using closed colonic loops. eh infection in wild- ...201323357502
novel tpr-containing subunit of tom complex functions as cytosolic receptor for entamoeba mitosomal transport.under anaerobic environments, the mitochondria have undergone remarkable reduction and transformation into highly reduced structures, referred as mitochondrion-related organelles (mros), which include mitosomes and hydrogenosomes. in agreement with the concept of reductive evolution, mitosomes of entamoeba histolytica lack most of the components of the tom (translocase of the outer mitochondrial membrane) complex, which is required for the targeting and membrane translocation of preproteins into ...201323350036
small rna pyrosequencing in the protozoan parasite entamoeba histolytica reveals strain-specific small rnas that target virulence genes.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.201323347563
catalysis by n-acetyl-d-glucosaminylphosphatidylinositol de-n-acetylase (pig-l) from entamoeba histolytica: new roles for conserved residues.we showed previously that entamoeba histolytica pig-l exhibits a novel metal-independent albeit metal-stimulated activity. using mutational and biochemical analysis, here we identify asp-46 and his-140 of the enzyme as being important for catalysis. we show that these mutations neither affect the global conformational of the enzyme nor alter its metal binding affinity. the defect in catalysis, due to the mutations, is specifically due to an effect on v(max) and not due to altered substrate affin ...201323341455
label-free electrochemical detection of an entamoeba histolytica antigen using cell-free yeast-scfv probes.inexpensive, simple and quick detection of pathogen antigens in human samples is a key global health objective. limiting factors include the cost and complexity of diagnostic tests that utilize antibody probes. herein, we present a method for label-free electrochemical detection of a protein from the enteric pathogen entamoeba histolytica using cell-free yeast-embedded antibody-like fragments (yeast-scfv) as novel affinity reagents.201323329132
tnfα-mediated liver destruction by kupffer cells and ly6chi monocytes during entamoeba histolytica infection.amebic liver abscess (ala) is a focal destruction of liver tissue due to infection by the protozoan parasite entamoeba histolytica (e. histolytica). host tissue damage is attributed mainly to parasite pathogenicity factors, but massive early accumulation of mononuclear cells, including neutrophils, inflammatory monocytes and macrophages, at the site of infection raises the question of whether these cells also contribute to tissue damage. using highly selective depletion strategies and cell-speci ...201323300453
prevalence and characters of entamoeba histolytica infection in saudi infants and children admitted with diarrhea at 2 main hospitals at south jeddah: a re-emerging serious infection with unusual presentation.in this study, entamoeba histolytica had high prevalence and unusual presentation by affecting high proportion of infants under 1 year; severe clinical manifestations, and laboratory findings that were known to be usually encountered in invasive amebiasis as significant leukocytosis for age, neutrophilic leukocytosis for age, and positive c-reactive protein were found among more than 50% of admitted saudi infants and children with e. histolytica infection in our locality. e. histolytica can be a ...201323287546
involvement of a putative intercellular signal-recognizing g protein-coupled receptor in the engulfment of salmonella by the protozoan tetrahymena.in an effort to investigate the molecular basis of protozoa engulfment-mediated hypervirulence of salmonella in cattle, we evaluated protozoan g protein-coupled receptors (gpcrs) as transducers of salmonella engulfment by the model protozoan tetrahymena. our laboratory previously demonstrated that non-pathogenic protozoa (including tetrahymena) engulf salmonella and then exacerbate its virulence in cattle, but the mechanistic details of the phenomenon are not fully understood. gpcrs were investi ...201326623315
structural determinants of rgs-rhogef signaling critical to entamoeba histolytica pathogenesis.g protein signaling pathways, as key components of physiologic responsiveness and timing, are frequent targets for pharmacologic intervention. here, we identify an effector for heterotrimeric g protein α subunit (ehgα1) signaling from entamoeba histolytica, the causative agent of amoebic colitis. ehgα1 interacts with this effector and guanosine triphosphatase-accelerating protein, ehrgs-rhogef, in a nucleotide state-selective fashion. coexpression of ehrgs-rhogef with constitutively active ehgα1 ...201323260656
quantification of stochastic noise of splicing and polyadenylation in entamoeba histolytica.alternative splicing and polyadenylation were observed pervasively in eukaryotic messenger rnas. these alternative isoforms could either be consequences of physiological regulation or stochastic noise of rna processing. to quantify the extent of stochastic noise in splicing and polyadenylation, we analyzed the alternative usage of splicing and polyadenylation sites in entamoeba histolytica using rna-seq. first, we identified a large number of rarely spliced alternative junctions and then showed ...201323258700
regulation of h2o2 stress-responsive genes through a novel transcription factor in the protozoan pathogen entamoeba histolytica.outcome of infection depends upon complex interactions between the invading pathogen and the host. as part of the host's innate immune response, the release of reactive oxygen and nitrogen species by phagocytes represents a major obstacle to the establishment of infection. the ability of the human parasite entamoeba histolytica to survive reactive oxygen and nitrogen species is central to its pathogenic potential and contributes to disease outcome. in order to define the transcriptional network ...201323250742
effectiveness of latex agglutination slide test in the diagnosis of imported invasive amoebiasis in the emergency department.we compared a latex agglutination test (lat) with enzyme-linked immunosorbent assay and indirect hemagglutination assay in the diagnosis of invasive amoebiasis. a retrospective biological records review has included 639 patients for whom these three serological tests were performed. the sensitivity of the lat was 97.8% and the specificity was 97%.201324125923
historical perspective on developmental concepts and terminology.in their ontogeny and phylogeny all living beings are historical entities. the revolution in biology of the 18th and 19th centuries that did away with the scala naturae according to which we humans, the acme of creation, "made a little lower than the angels," also led to the gradual realization that a humble one-celled protist ("protoctist"), such as entamoeba histolytica of ill repute [margulis and chapman, ] has the same 4-billion-year phylogeny as that of homo sapiens, vivid testimony to comm ...201324123982
homologous recombination occurs in entamoeba and is enhanced during growth stress and stage conversion.homologous recombination (hr) has not been demonstrated in the parasitic protists entamoeba histolytica or entamoeba invadens, as no convenient method is available to measure it. however, hr must exist to ensure genome integrity, and possible genetic exchange, especially during stage conversion from trophozoite to cyst. here we show the up regulation of mitotic and meiotic hr genes in entamoeba during serum starvation, and encystation. to directly demonstrate hr we use a simple pcr-based method ...201324098652
exploring the possible role of lysine acetylation on entamoeba histolytica virulence: a focus on the dynamics of the actin cytoskeleton.cytoskeleton remodeling can be regulated, among other mechanisms, by lysine acetylation. the role of acetylation on cytoskeletal and other proteins of entamoeba histolytica has been poorly studied. dynamic rearrangements of the actin cytoskeleton are crucial for amebic motility and capping formation, processes that may be effective means of evading the host immune response. here we report the possible effect of acetylation on the actin cytoskeleton dynamics and in vivo virulence of e. histolytic ...201324078923
a test of agent-based models as a tool for predicting patterns of pathogen transmission in complex landscapes.landscape complexity can mitigate or facilitate host dispersal, influencing patterns of pathogen transmission. spatial transmission of pathogens through landscapes, therefore, presents an important but not fully elucidated aspect of transmission dynamics. using an agent-based model (link) that incorporates gis data, we examined the effects of landscape information on the spatial patterns of host movement and pathogen transmission in a system of long-tailed macaques and their gut parasites. we fi ...201324063811
entamoeba histolytica contains an occludin-like protein that can alter colonic epithelial barrier function.the exact mechanism by which entamoeba histolytica disrupts the human colonic epithelium and invades the mucosa has yet to be clearly elucidated. e. histolytica produces a diverse array of putative virulent factors such as glycosidase, cysteine proteinases and amebapore that can modulate and/or disrupt epithelial barrier functions. however, it is currently thought that e. histolytica produces numerous other molecules and strategies to disrupt colonic mucosal defenses. in this study, we document ...201324058468
genomic distribution of sines in entamoeba histolytica strains: implication for genotyping.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 ...201323815468
identification of calcium-transporting atpases of entamoeba histolytica and cellular localization of the putative serca.calcium has an important role on signaling of different cellular processes in the protozoa parasite entamoeba histolytica, including development and pathogenesis. however, the systems that control calcium responses in this parasite are incompletely understood. calcium-atpases (ca(2+)-atpases) are proteins that play an important role in calcium homeostasis by catalyzing the active efflux of this ion from cytoplasm and are essential to the correct functioning of the cell machinery. here, we report ...201323800535
prevalence of intestinal parasitic infection among hiv positive persons who are naive and on antiretroviral treatment in hiwot fana specialized university hospital, eastern ethiopia.background. intestinal parasitic infection affects the health and quality of life of people living with hiv. this study was aimed to determine the prevalence of intestinal parasites among hiv positive individuals who are naive and who are on antiretroviral treatment (art) in hiwot fana specialized university hospital, eastern ethiopia. methods. a comparative cross-sectional study was conducted on 371 (112 art-naive group and 259 on art) hiv positive individuals. stool specimens were collected an ...201324052888
etiology of diarrhea in bangladeshi infants in the first year of life analyzed using molecular methods.diarrhea causes enormous morbidity and mortality in developing countries, yet the relative importance of multiple potential enteropathogens has been difficult to ascertain.201324041797
structural determinants of ubiquitin conjugation in entamoeba histolytica.ubiquitination is important for numerous cellular processes in most eukaryotic organisms, including cellular proliferation, development, and protein turnover by the proteasome. the intestinal parasite entamoeba histolytica harbors an extensive ubiquitin-proteasome system. proteasome inhibitors are known to impair parasite proliferation and encystation, suggesting the ubiquitin-proteasome pathway as a viable therapeutic target. however, no functional studies of the e. histolytica ubiquitination e ...201323209297
the bifunctional aldehyde-alcohol dehydrogenase controls ethanol and acetate production in entamoeba histolytica under aerobic conditions.by applying metabolic control analysis and inhibitor titration we determined the degree of control (flux control coefficient) of pyruvate:ferredoxin oxidoreductase (pfor) and bifunctional aldehyde-alcohol dehydrogenase (adhe) over the fluxes of fermentative glycolysis of entamoeba histolytica subjected to aerobic conditions. the flux-control coefficients towards ethanol and acetate formation determined for pfor titrated with diphenyleneiodonium were 0.07 and 0.09, whereas for adhe titrated with ...201323201265
src and pi3 k inhibitors affect the virulence factors of entamoeba histolytica.protein kinases (pks) of parasitic protozoa are being evaluated as drug targets. a large number of protein kinases within the protein kinome of entamoeba histolytica strongly suggest that protein phosphorylation is a key component of pathogenesis regulation by this parasite. pi3 k and src are kinases previously described in this parasite, but their role is poorly understood. here, the effect of src-1-inhibitor and pi3 k inhibitor (wortmannin) on the virulence factors of e. histolytica was evalua ...201323058125
loop-mediated isothermal amplification (lamp) assay for rapid detection of entamoeba histolytica in amoebic liver abscess.amoebic liver abscess (ala) is the most common extra intestinal manifestation of invasive amoebiasis caused by entamoeba histolytica. the lack of early and accurate diagnostic test to differentiate various causes of liver abscess necessitates more reliable laboratory diagnostic test. the present study was conducted to assess the applicability of loop-mediated isothermal amplification (lamp) assay for detection of e. histolytica in ala cases. fifty patients (n = 50) with clinical suspicion of ala ...201323054695
biochemical and functional characterization of novel nadh kinase in the enteric protozoan parasite entamoeba histolytica.nad(h) kinase catalyzes the phosphorylation of nad(h) to form nadp(h) using atp or inorganic polyphosphate as a phosphoryl donor. while the enzyme is conserved throughout prokaryotes and eukaryotes, remarkable differences in kinetic parameters including substrate preference, cation dependence, and physiological roles exist among the organisms. in the present study, we biochemically characterized nad(h) kinase from the anaerobic/microaerophilic fermentative protozoan parasite entamoeba histolytic ...201323069387
identification of dihydropyrimidine dehydrogenase as a virulence factor essential for the survival of entamoeba histolytica in glucose-poor environments.adaptation to nutritional changes is a key feature for successful survival of a pathogen within its host. the protozoan parasite entamoeba histolytica normally colonizes the human colon and in rare occasions, this parasite spread to distant organs, such as the liver. e. histolytica obtains most of its energy from the fermentation of glucose into ethanol. in this study, we were intrigued to know how this parasite reacts to changes in glucose availability and we addressed this issue by performing ...201323016994
structure-function correlations of pulmonary surfactant protein sp-b and the saposin-like family of proteins.pulmonary surfactant is a lipid-protein complex secreted by the respiratory epithelium of mammalian lungs, which plays an essential role in stabilising the alveolar surface and so reducing the work of breathing. the surfactant protein sp-b is part of this complex, and is strictly required for the assembly of pulmonary surfactant and its extracellular development to form stable surface-active films at the air-liquid alveolar interface, making the lack of sp-b incompatible with life. in spite of i ...201322996193
breast milk parasite-specific antibodies and protection from amebiasis and cryptosporidiosis in bangladeshi infants: a prospective cohort study.in this prospective cohort study, the presence of parasite-specific immunoglobulin a in breast milk was associated with protection of bangladeshi infants from cryptosporidiosis and amebiasis. our findings suggest that passive immunity could be harnessed for the prevention of entamoeba histolytica and cryptosporidium species infection in children living in endemic regions.201323243179
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