Publications

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activity of extracts and procesterol from calotropis gigantea against entamoeba histolytica.extracts from the root bark of calotropis gigantea were subjected to bioactivity-guided fractionation using growth inhibitory effects against entamoeba histolytica. the n-hexane soluble portion of the chloroform extract showed in vitro antiamoebic activity against the hk-9 strain of entamoeba histolytica. chromatographic separation of the chloroform extract afforded the known compound, procesterol, which showed activity against e. histolytica.201020614811
human amebiasis: breaking the paradigm?for over 30 years it has been established that the entamoeba histolytica protozoan included two biologically and genetically different species, one with a pathogenic phenotype called e. histolytica and the other with a non-pathogenic phenotype called entamoeba dispar. both of these amoebae species can infect humans. e. histolytica has been considered as a potential pathogen that can cause serious damage to the large intestine (colitis, dysentery) and other extraintestinal organs, mainly the live ...201020617021
demographic and ecological effects on patterns of parasitism in eastern chimpanzees (pan troglodytes schweinfurthii) in gombe national park, tanzania.from january 2006 to january 2008, we collected 1,045 fecal samples from 90 individually-recognized, free-ranging, eastern chimpanzees (pan troglodytes schweinfurthii) inhabiting gombe national park, tanzania to determine how patterns of parasitism are affected by demographic and ecological covariates. seventeen parasite species were recovered, including eight nematodes (oesophagostomum sp., necator sp., probstmayria gombensis, strongyloides fulleborni, ascaris sp., trichuris sp., abbreviata cau ...201020623606
pyruvate:ferredoxin oxidoreductase and bifunctional aldehyde-alcohol dehydrogenase are essential for energy metabolism under oxidative stress in entamoeba histolytica.the in vitro entamoeba histolytica pyruvate:ferredoxin oxidoreductase (ehpfor) kinetic properties and the effect of oxidative stress on glycolytic pathway enzymes and fluxes in live trophozoites were evaluated. ehpfor showed a strong preference for pyruvate as substrate over other oxoacids. the enzyme was irreversibly inactivated by a long period of saturating o(2) exposure (ic(50) 0.034 mm), whereas short-term exposure (< 30 min) leading to > 90% inhibition allowed for partial restoration by ad ...201020629749
concurrent amoebic and klebsiella pneumoniae liver abscess in an immunocompetent patient: an unusual case report and review of the literature. 201020649739
the jacob2 lectin of the entamoeba histolytica cyst wall binds chitin and is polymorphic.the infectious and diagnostic form of entamoeba histolytica (eh), cause of amebic dysentery and liver abscess, is the quadranucleate cyst. the cyst wall of entamoeba invadens (ei), a model for eh, is composed of chitin fibrils and three sets of chitin-binding lectins that cross-link chitin fibrils (multivalent jacob lectins), self-aggregate (jessie lectins), and remodel chitin (chitinase). the goal here was to determine how well the ei model applies to entamoeba cysts from humans.201020652032
in memoriam: louis s. "buddy" diamond (1920-2009). 201020662997
design, synthesis, and in vitro antiprotozoal, antimycobacterial activities of n-{2-[(7-chloroquinolin-4-yl)amino]ethyl}ureas.we have synthesized a new series of quinoline tripartite hybrids from chloroquine, ethambutol, and isoxyl drugs, using a short synthetic route. compounds 1-8 were tested in vitro against five protozoa (giardia intestinalis, trichomonas vaginalis,entamoeba histolytica, leishmania mexicana and trypanosoma cruzi) and mycobacterium tuberculosis. n-(4-butoxyphenyl)-n'-{2-[(7-chloroquinolin-4-yl)amino]ethyl}urea (6) was the most active compound against all parasites tested. compound 6 was 670 times mo ...201020674375
regulation of virulence of entamoeba histolytica by the ure3-bp transcription factor.it is not understood why only some infections with entamoeba histolytica result in disease. the calcium-regulated transcription factor upstream regulatory element 3-binding protein (ure3-bp) was initially identified by virtue of its role in regulating the expression of two amebic virulence genes, the gal/galnac lectin and ferredoxin. here we tested whether this transcription factor has a broader role in regulating virulence. a comparison of in vivo to in vitro parasite gene expression demonstrat ...201020689746
the tropical brown alga lobophora variegata: a source of antiprotozoal compounds.lobophora variegata, a brown alga collected from the coast of the yucatan peninsula, mexico, was studied for antiprotozoal activity against giardia intestinalis, entamoeba histolytica and trichomonas vaginalis. the whole extract showed the highest activity against t. vaginalis, with an ic(50) value of 3.2 microg/ml. for the fractions, the best antiprotozoal activity was found in non-polar fractions. the chloroform fraction of the extract contained a major sulfoquinovosyldiacylglycerol (sqdg), id ...201020479979
synthesis, characterization and biological evaluation of novel 6-ferrocenyl-4-aryl-2-substituted pyrimidine derivatives.a new series of 6-ferrocenyl-4-aryl-2-substituted pyrimidines were synthesized and evaluated for in vitro antiamoebic activity against hm1:imss strain of entamoeba histolytica. out of 16 compounds 10 compounds have shown ic(50) values in the range of 0.41-1.73 microm and 1.80 microm. pyrimidine derivatives having thiomethyl group, chloro group and mono-, di-, and trimethoxy substitution, exhibited higher antiamoebic activity than the reference drug metronidazole (ic(50)=1.80 microm). the toxicol ...201020488588
prevalence of parasitic contamination of raw vegetables in villages of qazvin province, iran.we conducted a study to determine the extent of parasitic contamination of raw vegetables distributed by wholesalers in villages of qazvin province, iran. vegetables collected for the study were leek, parsley, lettuce, coriander, radish, spring onion, tarragon, basil, spearmint, and cress. samples of each vegetable were collected at monthly intervals for 6 months from may to october 2008, yielding a total of 654 samples. samples of each vegetable collected at each monthly interval were selected ...201020491596
evaluation of a new single-tube multiprobe real-time pcr for diagnosis of entamoeba histolytica and entamoeba dispar.a single-tube multiprobe real-time pcr assay for simultaneous detection of entamoeba histolytica and entamoeba dispar was developed. one primer pair with 2 species-specific probes was designed based on new ssu rna regions of the ribosomal dna-containing episome. the sensitivity is 1 parasite per milliliter of feces and thus superior to the conventional nested pcr and comparable to other published real-time pcr protocols. the applicability for clinical diagnosis was validated with 218 stool speci ...201020496961
bioinformatic analysis of entamoeba histolytica sine1 elements.invasive amoebiasis, caused by infection with the human parasite entamoeba histolytica remains a major cause of morbidity and mortality in some less-developed countries. genetically e. histolytica exhibits a number of unusual features including having approximately 20% of its genome comprised of repetitive elements. these include a number of families of sines - non-autonomous elements which can, however, move with the help of partner lines. in many eukaryotes sine mobility has had a profound eff ...201020497534
disinfection efficacy of sodium dichloroisocyanurate (nadcc) against common food-borne intestinal protozoa.the present study was conducted to investigate the efficacy of sodium dichloroisocyanurate (nadcc) on the infective stages of common food-borne intestinal protozoa; entamoeba histolytica (e. histolytica), giardia lamblia (g. lamblia), cryptosporidium, cyclospora and microsporidia; beside its effect on raw green vegetables and fruits. parasites, isolated from stool of patients with diarrhea or dysentery, were exposed to nadcc solution (1g/l) for one and two hours. disinfection effect of nadcc was ...201020503596
detection of the endosomal sorting complex required for transport in entamoeba histolytica and characterization of the ehvps4 protein.eukaryotic endocytosis involves multivesicular bodies formation, which is driven by endosomal sorting complexes required for transport (escrt). here, we showed the presence and expression of homologous escrt genes in entamoeba histolytica. we cloned and expressed the ehvps4 gene, an escrt member, to obtain the recombinant ehvps4 and generate specific antibodies, which immunodetected ehvps4 in cytoplasm of trophozoites. bioinformatics and biochemical studies evidenced that rehvps4 is an atpase, w ...201020508821
entamoeba histolytica: differential gene expression during programmed cell death and identification of early pro- and anti-apoptotic signals.we have demonstrated that programmed cell death (pcd) in entamoeba histolytica is induced in vitro by g418 aminoglycoside antibiotic. to ascertain if biochemical and morphological changes previously observed are paired to molecular changes that reflect a genetic program, we looked here for early differential gene expression during the induction of pcd. using cdna-amplified fragment length polymorphisms (aflps) and in silico derived analysis we showed in e. histolytica a differential gene express ...201020515683
repetitive elements in parasitic protozoa.a recent paper published in bmc genomics suggests that retrotransposition may be active in the human gut parasite entamoeba histolytica. this adds to our knowledge of the various types of repetitive elements in parasitic protists and the potential influence of such elements on pathogenicity.201020529240
serum-dependent selective expression of ehtmkb1-9, a member of entamoeba histolytica b1 family of transmembrane kinases.entamoeba histolytica transmembrane kinases (ehtmks) can be grouped into six distinct families on the basis of motifs and sequences. analysis of the e. histolytica genome revealed the presence of 35 ehtmkb1 members on the basis of sequence identity (>or=95%). only six homologs were full length containing an extracellular domain, a transmembrane segment and an intracellular kinase domain. reverse transcription followed by polymerase chain reaction (rt-pcr) of the kinase domain was used to generat ...201020532220
diagnosis of amebic liver abscess and amebic colitis by detection of entamoeba histolytica dna in blood, urine, and saliva by a real-time pcr assay.the noninvasive diagnosis of amebic liver abscess is challenging, as most patients at the time of diagnosis do not have a concurrent intestinal infection with entamoeba histolytica. fecal testing for e. histolytica parasite antigen or dna is negative in most patients. a real-time pcr assay was evaluated for detection of e. histolytica dna in blood, urine, and saliva samples from amebic liver abscess as well as amebic colitis patients in bangladesh. a total of 98 amebic liver abscess and 28 amebi ...201020534800
crystal structure and trimer-monomer transition of n-terminal domain of ehcabp1 from entamoeba histolytica.ehcabp1 is a well-characterized calcium binding protein from entamoeba histolytica with four canonical ef-hand motifs. the crystal structure of ehcabp1 reveals the trimeric organization of n-terminal domain. the solution structure obtained at ph 6.0 indicated its monomeric nature, similar to that of calmodulin. recent domain-wise studies showed clearly that the n-terminal domain of ehcabp1 is capable of performing most of the functions of the full-length protein. additionally, the mode of target ...201020550906
comparison of serine-rich protein genes of entamoeba histolytica isolates obtained from institutions for the mentally retarded in kanagawa and shizuoka prefectures, japan.in japan, amebiasis has been observed in homosexual men, in institutionalized persons, and in overseas travelers. we have previously reported an outbreak of amebiasis that occurred from 1986 to 1994 in institutions for the mentally retarded in kanagawa and shizuoka prefectures in eastern japan. entamoeba histolytica but not entamoeba dispar was identified in entamoeba cultures obtained from cyst passers in four institutions located in different municipalities in this region. in the present study ...201020556425
new assembly, reannotation and analysis of the entamoeba histolytica genome reveal new genomic features and protein content information.in order to maintain genome information accurately and relevantly, original genome annotations need to be updated and evaluated regularly. manual reannotation of genomes is important as it can significantly reduce the propagation of errors and consequently diminishes the time spent on mistaken research. for this reason, after five years from the initial submission of the entamoeba histolytica draft genome publication, we have re-examined the original 23 mb assembly and the annotation of the pred ...201020559563
identification of entamoeba histolytica trophozoites in fresh stool sample: comparison of three staining techniques and study on the viability period of the trophozoites.entamoeba histolytica causes about 50 million infections worldwide with a death rate of over 100,000 annually. in endemic developing countries where resources are limited, microscopic examinations based on wheatley trichrome staining is commonly used for diagnosis of intestinal amoebiasis. other than being a time-consuming method, it must be performed promptly after stool collection as trophozoites disintegrate rapidly in faeces. the aim of this study was to compare the efficacies of eosin-y, wh ...201020562817
prevalence of entamoeba histolytica in humans.the present survey was carried out to determine the prevalence of human amebiasis. during the study, 1360 fecal samples were examined from february 2007 to december 2007 at nishtar hospital, multan. out of 1360 hosts examined, 295 were infected with e. histolytica. the overall prevalence of e. histolytica was (21.69%). relationship between sex and e. histolytica in humans showed that the infection of e. histolytica was more prevalent in male hosts (22.36%) as compared to female hosts (20.9%). ho ...201020566452
molecular identification of entamoeba spp. in captive nonhuman primates.this study describes the molecular identification of 520 entamoeba-positive fecal samples from a large and diverse population of captive nonhuman primates (nhp). the results revealed the presence of entamoeba histolytica (nhp variant only), e. dispar, e. moshkovskii, e. hartmanni, e. coli, and e. polecki-like organisms.201020573870
a phylogenetic survey of myotubularin genes of eukaryotes: distribution, protein structure, evolution, and gene expression.phosphorylated phosphatidylinositol (ptdins) lipids, produced and modified by ptdins kinases and phosphatases, are critical to the regulation of diverse cellular functions. the myotubularin ptdins-phosphate phosphatases have been well characterized in yeast and especially animals, where multiple isoforms, both catalytically active and inactive, occur. myotubularin mutations bring about disruption of cellular membrane trafficking, and in humans, disease. previous studies have suggested that myotu ...201020576132
pyogenic versus amoebic liver abscesses. a comparative clinical study in a series of 58 patients.to compare the clinical and epidemiological characteristics of patients with pyogenic liver abscess (pla) and with amebic liver abscess (aha) in order to determine the potential factors that may help improve diagnosis and treatment for this disease.201020361845
intestinal parasitic infections among intellectual disability children in rehabilitation centers of northern iran.parasitic infection is highly prevalent throughout the developing countries of the world. these infections are the major problem in rehabilitation centers for the mentally retarded. there have been many reports about the prevalence of parasitic infection among different groups of people in iran; however, the epidemiological data in intellectual disability (id) individuals are rare and there are no such data from northern iran. the aim of the present study was to determine the incidence of intest ...201020363588
a novel entamoeba histolytica cysteine proteinase, ehcp4, is key for invasive amebiasis and a therapeutic target.entamoeba histolytica cysteine proteinases (ehcps) play a key role in disrupting the colonic epithelial barrier and the innate host immune response during invasion of e. histolytica, the protozoan cause of human amebiasis. ehcps are encoded by 50 genes, of which ehcp4 (ehcp-a4) is the most up-regulated during invasion and colonization in a mouse cecal model of amebiasis. up-regulation of ehcp4 in vivo correlated with our finding that co-culture of e. histolytica trophozoites with mucin-producing ...201020378535
localization and targeting of an unusual pyridine nucleotide transhydrogenase in entamoeba histolytica.pyridine nucleotide transhydrogenase (pnt) catalyzes the direct transfer of a hydride-ion equivalent between nad(h) and nadp(h) in bacteria and the mitochondria of eukaryotes. pnt was previously postulated to be localized to the highly divergent mitochondrion-related organelle, the mitosome, in the anaerobic/microaerophilic protozoan parasite entamoeba histolytica based on the potential mitochondrion-targeting signal. however, our previous proteomic study of isolated phagosomes suggested that pn ...201020382757
calpain-dependent cleavage of shp-1 and shp-2 is involved in the dephosphorylation of jurkat t cells induced by entamoeba histolytica.host cell death induced by entamoeba histolytica is an important mechanism for both host defence and microbial immune evasion during human amoebiasis. however, the signalling pathways underlying cell death induced by e. histolytica are not fully understood. this study investigated the involvement of the protein tyrosine phosphatases (ptps) shp-1 and shp-2 in the dephosphorylation associated with e. histolytica-induced host cell death. incubation with e. histolytica resulted in a marked decrease ...201020398180
parasiticidal effect of 16alpha-bromoepiandrosterone (epibr) in amoebiasis and cysticercosis.the effect of the dehydroepiandrosterone analog 16alpha-bromoepiandrosterone (epibr) was tested on the tapeworm taenia crassiceps and the protist entamoeba histolytica, both in vivo and in vitro. administration of epibr prior to infection with cysticerci in mice reduced the parasite load by 50% compared with controls. epibr treatment induced 20% reduction on the development of amoebic liver abscesses in hamsters. in vitro treatment of t. crassiceps and e. histolytica cultures with epibr, reduced ...201020403456
application of real-time pcr for the differentiation of entamoeba histolytica and e. dispar in cyst-positive faecal samples from 130 immigrants living in spain.in an effort to improve the diagnosis of intestinal amoebiasis, a real-time pcr has been used for the detection and differentiation of entamoeba histolytica and e. dispar infections in african or south american immigrants who live in spain. faecal samples from all of the 130 subjects had apparently been found to contain e. histolytica/e. dispar cysts by microscopical examination. using the real-time pcr, e. histolytica dna was detected in faecal samples from only 10 (7.7%) of the immigrants, wit ...201020406581
cytokine and chemokine responses in adults, newborns and children exposed to entamoeba histolytica/dispar, onchocerca volvulus and plasmodium falciparum.cytokine and chemokine response profiles were studied in newborns, 10-yr-old children and post partum mothers. all study groups were repeatedly exposed to entamoeba histolytica, onchocerca volvulus and plasmodium falciparum infections as indicated by their immunoglobulin (igg) responses to parasite-specific antigens. as key indicators for regulatory and pro-inflammatory cytokine and chemokine responses, interferon (ifn)gamma and regulatory il-10 were investigated, along with the chemokines mip-1 ...201020408971
precision-cut hamster liver slices as an ex vivo model to study amoebic liver abscess.entamoeba histolytica is the etiological agent of amoebiasis, the second cause of global morbidity and mortality due to parasitic diseases in humans. in approximately 1% of the cases, amoebas penetrate the intestinal mucosa and spread to other organs, producing extra-intestinal lesions, among which amoebic liver abscess (ala) is the most common. to study ala, in vivo and in vitro models are used. however, animal models may pose ethical issues, and are time-consuming and costly; and cell cultures ...201020412797
etiological approach to chronic urticaria.in 1769, william cullen introduced the word "urticaria" (transient edematous papules, plaque with itching). urticaria affects 15-25% of people at least once in their life time. it is a clinical reaction pattern triggered by many factors causing the liberation of vasoactive substances such as histamine, prostaglandins and kinins. urticaria is classified according to its duration into acute (< 6 weeks duration) and chronic (>6 weeks duration). various clinical investigations may be initiated to di ...201020418974
using hidden markov models to discover new protein transport machines.protein import and export pathways are driven by protein translocases, often comprised of multiple subunits, and usually conserved across a range of organisms. protein import into mitochondria is fundamental to eukaryotic organisms and is initiated when substrate proteins are translocated across the mitochondrial outer membrane by the tom complex. the essential subunit of this complex is a protein called tom40, which is probably a beta-barrel in structure and serves as the translocation pore. we ...201020419416
genomic organization of eukaryotic trnas.surprisingly little is known about the organization and distribution of trna genes and trna-related sequences on a genome-wide scale. while trna gene complements are usually reported in passing as part of genome annotation efforts, and peculiar features such as the tandem arrangements of trna gene in entamoeba histolytica have been described in some detail, systematic comparative studies are rare and mostly restricted to bacteria. we therefore set out to survey the genomic arrangement of trna ge ...201020426822
insights into entamoeba histolytica virulence modulation.entamoeba histolytica is able to invade human tissues by means of several molecules and biological properties related to the virulence. pathogenic amebas use three major virulence factors, gal/galnac lectin, amebapore and proteases, for lyse, phagocytose, kill and destroy a variety of cells and tissues in the host. responses of the parasite to host components such as mucins and bacterial flora influence the behavior of pathogenic amebas altering their expression of virulence factors. the relativ ...201020429861
recent insights in pre-mrna 3'-end processing signals and proteins in the protozoan parasite entamoeba histolytica.the messenger rna precursors (pre-mrna) 3'-end processing occurs in a two-step co-transcriptional coupled reaction, denoted as cleavage and polyadenylation. both processes depend on trans-acting factors interacting in a coordinated manner with cis-sequence motifs located at the 3' untranslated region of transcripts. in this paper, we reviewed mechanisms involved in pre-mrna processing in eukaryotic organisms, including our own findings about sequences and proteins potentially involved in mrna 3' ...201020429864
synthesis and biological activity of 2-(trifluoromethyl)-1h-benzimidazole derivatives against some protozoa and trichinella spiralis.a series of 2-(trifluoromethyl)-1h-benzimidazole derivatives (1a-1i) were synthesized via phillips cyclocondensation of a substituted 1,2-phenylenediamine and trifluoroacetic acid. the synthesized compounds were evaluated in vitro against various protozoan parasites: giardia intestinalis, entamoeba histolytica, trichomonas vaginalis and leishmania mexicana, and they showed nanomolar activities against the first three protozoa tested. the compounds were also tested in vitro and in vivo against th ...201020430484
hyperendemic h. pylori and tapeworm infections in a u.s.-mexico border population.a higher incidence of infectious disease has been documented in u.s. regions bordering mexico compared with non-border areas. we assessed the prevalence of important gastrointestinal infections in ciudad juarez, mexico, and el paso, texas, the largest binational community along the u.s.-mexico border.201020433039
bacteriological and parasitological assessment of food handlers in the omdurman area of sudan.pathogenic organisms are thought to be widely distributed among food handlers. this study was designed to assess the prevalence of carriers of some pathogenic bacteria and intestinal parasites among food handlers in the city of omdurman, sudan.201020434126
conservation and function of rab small gtpases in entamoeba: annotation of e. invadens rab and its use for the understanding of entamoeba biology.entamoeba invadens is a reptilian enteric protozoan parasite closely related to the human pathogen entamoeba histolytica and a good model organism of encystation. to understand the molecular mechanism of vesicular trafficking involved in the encystation of entamoeba, we examined the conservation of rab small gtpases between the two species. e. invadens has over 100 rab genes, similar to e. histolytica. most of the rab subfamilies are conserved between the two species, while a number of species-s ...201020434444
hydrogen peroxide-induced apoptosis-like cell death in entamoeba histolytica.the microaerophilic intestinal parasitic protozoan entamoeba histolytica has been previously shown to be highly susceptible to oxidative stress induced by hydrogen peroxide. however the mechanism of cell death was not investigated. studies presented in this paper demonstrate several morphological features in the parasite when exposed to h(2)o(2) which are identical to metazoan apoptotic phenotype indicating a possible apoptosis-like cell death exhibited by e. histolytica in response to h(2)o(2) ...201020079879
members of the entamoeba histolytica transmembrane kinase family play non-redundant roles in growth and phagocytosis.entamoeba histolytica contains a large and novel family of transmembrane kinases (tmks). the expression patterns of the e. histolytica tmks in individual trophozoites and the roles of the tmks for sensing and responding to extracellular cues were incompletely characterised. here we provide evidence that single cells express multiple tmks and that tmk39 and tmk54 likely serve non-redundant cellular functions. laser-capture microdissection was used in conjunction with microarray analysis to demons ...201020083116
acetate formation in the energy metabolism of parasitic helminths and protists.formation and excretion of acetate as a metabolic end product of energy metabolism occurs in many protist and helminth parasites, such as the parasitic helminths fasciola hepatica, haemonchus contortus and ascaris suum, and the protist parasites, giardia lamblia, entamoeba histolytica, trichomonas vaginalis as well as trypanosoma and leishmania spp. in all of these parasites acetate is a main end product of their energy metabolism, whereas acetate formation does not occur in their mammalian host ...201020085767
freezing of stool samples improves real-time pcr detection of entamoeba dispar and entamoeba histolytica.pcr as a tool for intestinal parasite diagnosis is expanding since differentiation between entamoeba histolytica and entamoeba dispar cysts is impossible with microscopy. since pre-analytical factors influence dna detection, we evaluated with real-time pcr the influence of storage time and temperature. we demonstrated an improved dna detection in frozen stool samples.201020085792
the nf-kappab p50 subunit is protective during intestinal entamoeba histolytica infection of 129 and c57bl/6 mice.entamoeba histolytica is the agent of amebic colitis. in this work we examined the intestinal nf-kappab response to this parasite. using an enzyme-linked immunosorbent assay (elisa) and an electrophoretic mobility shift assay, we found that the nf-kappab subunit p50 predominated in nuclear extracts of whole cecal tissue and of isolated crypts from mice inoculated with e. histolytica. p50 was protective, since c57bl/6 and 129 mice in which there was targeted deletion of this subunit were more sus ...201020086086
prevalence and spatial distribution of entamoeba histolytica/dispar and giardia lamblia among schoolchildren in agboville area (côte d'ivoire).new efforts are being made to improve understanding of the epidemiology of the helminths and intensifying the control efforts against these parasites. in contrast, relatively few studies are being carried out in this direction for the intestinal protozoa. to contribute to a better comprehension of the epidemiology of the intestinal protozoa, prevalence, and spatial distribution of entamoeba histolytica/dispar and giardia lamblia, and their association with drinking water supplies, were determine ...201020087416
epithelial cell apoptosis facilitates entamoeba histolytica infection in the gut.entamoeba histolytica is the protozoan parasite that causes amebic colitis. the parasite triggers apoptosis on contact with host cells; however, the biological significance of this event during intestinal infection is unclear. we examined the role of apoptosis in a mouse model of intestinal amebiasis. histopathology revealed that abundant epithelial cell apoptosis occurred in the vicinity of amoeba in histological specimens. epithelial cell apoptosis occurred rapidly on co-culture with amoeba in ...201020093500
biochemical and structural properties of chimeras constructed by exchange of cofactor-binding domains in alcohol dehydrogenases from thermophilic and mesophilic microorganisms.the cofactor-binding domains (residues 153-295) of the alcohol dehydrogenases from the thermophile thermoanaerobacter brockii (tbadh), the mesophilic bacterium clostridium beijerinckii (cbadh), and the protozoan parasite entamoeba histolytica (ehadh1) have been exchanged. three chimeras have been constructed. in the first chimera, the cofactor-binding domain of thermophilic tbadh was replaced with the cofactor-binding domain of its mesophilic counterpart cbadh [chimera chi21((tct))]. this domain ...201020102159
differences in the transcriptome signatures of two genetically related entamoeba histolytica cell lines derived from the same isolate with different pathogenic properties.the availability of two genetically very similar cell lines (a and b) derived from the laboratory isolate entamoeba histolytica hm-1:imss, which differ in their virulence properties, provides a powerful tool for identifying pathogenicity factors of the causative agent of human amoebiasis. cell line a is incapable inducing liver abscesses in gerbils, whereas interaction with cell line b leads to considerable abscess formation. phenotypic characterization of both cell lines revealed that trophozoi ...201020102605
vanadium complexes having [v(iv)o](2+) and [v(v)o(2)](+) cores with binucleating dibasic tetradentate ligands: synthesis, characterization, catalytic and antiamoebic activities.binucleating hydrazones ch(2)(h(2)sal-bhz)(2) (i) and ch(2)(h(2)sal-fah)(2) (ii), derived from 5,5'-methylbis(salicylaldehyde) and benzoylhydrazide or 2-furoylhydrazide, react with [v(iv)o(acac)(2)] to give dinuclear v(iv)o-complexes [ch(2){v(iv)o(sal-bhz)(h(2)o)}(2)] 1 and [ch(2){v(iv)o(sal-fah)(h(2)o)}(2)] 4, respectively. in the presence of koh or csoh.h(2)o, oxidation of 1 and 2 results in the formation of dioxidovanadium(v) complexes, k(2)[ch(2){v(v)o(2)(sal-bhz)}(2)].2h(2)o 2, k(2)[ch(2){v ...201020104362
new dioxazole derivatives: synthesis and effects on the growth of entamoeba histolytica and giardia intestinalis.cyclization of oxime with different aldehydes and ketones under basic condition led to the formation of new dioxazole derivatives and the structure was elucidated by spectral data. the effects of diaoxazoles on the inhibition of growth of entamoeba histolytica and giardia intestinalis in vitro have been determined, and selected compounds further investigated for their toxicity. sar showed that the compounds with 5-nitrothiophene group at the 3-postion of the diaoxazole ring were more active than ...201020122767
hydrogen peroxide induces apoptosis-like death in entamoeba histolytica trophozoites.programmed cell death (pcd) is an essential process in the growth and development of multicellular organisms. however, accumulating evidence indicates that unicellular eukaryotes can also undergo pcd with apoptosis-like features. this study demonstrates that after exposure to 0.8 mm h(2)o(2) for 9 h entamoeba histolytica presents morphological and biochemical evidence of apoptosis-like death. morphological characteristics of apoptosis-like death including dna fragmentation, increased vacuolizati ...201020299403
identification of four entamoeba histolytica organellar dna polymerases of the family b and cellular localization of the ehodp1 gene and ehodp1 protein.we report the identification of a family of four active genes (ehodp1, ehodp2, ehodp3, and ehodp4) encoding putative dna polymerases in entamoeba histolytica, the protozoan parasite responsible of human amoebiasis. the four ehodp genes show similarity to dna polymerases encoded in fungi and plant mitochondrial plasmids. ehodp polypeptides conserve the 3'-5' exonuclease ii and 5'-3' polymerization domains, and they have the i, ii, and iii conserved boxes that characterize them as dna polymerases ...201020300437
protection against murine intestinal amoebiasis induced by oral immunization with the 29 kda antigen of entamoeba histolytica and cholera toxin.entamoeba histolytica antigens recognized by salivary iga from infected patients include the 29 kda antigen (eh29), an alkyl hydroperoxide reductase. here, we investigate the potential of recombinant eh29 and an eh29-cholera toxin subunit b (ctxb) fusion protein to confer protection against intestinal amoebiasis after oral immunization. the purified eh29-ctxb fusion retained the critical ability to bind ganglioside gm(1), as determined by elisa. oral immunization of c3h/hej mice with eh29 admini ...201020303954
the immunopathogenesis of entamoeba histolytica.amebiasis is the disease caused by the enteric dwelling protozoan parasite entamoeba histolytica. the who considers amebiasis as one of the major health problems in developing countries; it is surpassed by only malaria and schistosomiasis for death caused by parasitic infection. e. histolytica primarily lives in the colon as a harmless commensal, but is capable of causing devastating dysentery, colitis and liver abscess. what triggers the switch to a pathogenic phenotype and the onset of disease ...201020303955
discrimination of entamoeba moshkovskii in patients with gastrointestinal disorders by single-round pcr.entamoeba moshkovskii and entamoeba dispar are impossible to differentiate microscopically from the pathogenic species entamoeba histolytica. there are limited data on the prevalence of these commensal parasites in iran. we utilized a single-round pcr assay to determine the prevalence of e. moshkovskii, e. dispar, and e. histolytica in stool samples from iranian patients infected with gastrointestinal disorders. after culturing of microscopy-positive isolates and extraction of dna, pcr was carri ...201020332579
the essentials of protein import in the degenerate mitochondrion of entamoeba histolytica.several essential biochemical processes are situated in mitochondria. the metabolic transformation of mitochondria in distinct lineages of eukaryotes created proteomes ranging from thousands of proteins to what appear to be a much simpler scenario. in the case of entamoeba histolytica, tiny mitochondria known as mitosomes have undergone extreme reduction. only recently a single complete metabolic pathway of sulfate activation has been identified in these organelles. the e. histolytica mitosomes ...201020333239
entamoeba histolytica and e. dispar trophozoites in the liver of hamsters: in vivo binding of antibodies and complement.abstract:201020338063
ehncabp166: a nucleocytoplasmic actin-binding protein from entamoeba histolytica.the actin cytoskeleton consists of multiple actin binding proteins (abps) that participate cooperatively in different cellular functions such as the maintenance of polarity and cell motility as well as the invasion of target cells and regulation of gene expression, among others. due to the important role of abps in the pathogenesis of entamoeba histolytica, the role of a new nucleocytoplasmic abp from e. histolytica named ehncabp166 was investigated. the ehncabp166 gene encodes a protein with an ...201020338197
[the distribution of intestinal parasites detected in the dokuz eylul university medical faculty hospital between 2005 and 2008.]a retrospective evaluation of the data from 14,246 patients with gastrointestinal complaints who presented at the parasitology laboratory of the dokuz eylul university medical faculty hospital between january 2005 and december 2008 was carried out. fecal samples of all patients were examined using native-lugol and the trichrome and kinyoun acid-fast staining method after sedimentation in fecal concentration tubes. one or more parasites were detected in 1320 (9.3%) of the patients. the distributi ...201020340084
association between tnf-alpha and entamoeba histolytica diarrhea.an association between tumor necrosis factor alpha (tnf-alpha) and entamoeba histolytica diarrhea was assessed in a cohort of 138 non-related bangladeshi children who have been prospectively followed since 2001. peripheral blood mononuclear cells (pbmcs) obtained at study entry were purified, cultured, and stimulated with soluble amebic antigen before cytokine measurement from supernatant. higher levels of tnf-alpha were associated with increased risk of first (p = 0.01) and recurrent e. histoly ...201020348510
entamoeba histolytica: soluble and membrane-associated neutral sphingomyelinase-c and other unidentified esterase activity.sphingomyelinase (smase) activity was measured in entamoeba histolytica particulate and soluble subcellular fractions. the effects on smase of incubation time, total protein concentration, ph, and several divalent cations were determined. smase-c and other unidentified esterase activity were detected in soluble and particulate fractions. smase-c was 94.5-96.0% higher than the unidentified esterase activity. soluble and insoluble smase-c specific activities increased with protein dose and incubat ...201020350542
parasitic contamination in wastewater and sludge samples in tunisia using three different detection techniques.the limited availability of water results in the reuse of wastewater or sludge. the tunisian wastewater regulatory guidelines have specific limits for ova of helminths (<1 egg/l) but none for protozoan parasites. we assessed the presence and loads of parasites in 20 samples of raw, treated wastewater and sludge collected from six wastewater treatment plants. samples were tested by microscopy using the modified bailenger method (mbm), immunomagnetic separation (ims) followed by immunofluorescent ...201020352447
urinary hyaluronidase activity in rats infected with blastocystis hominis--evidence for invasion?the fact whether blastocystis hominis can invade has always been in question. apart from a few sporadic studies such as that done on gnotobiotic guinea pigs which showed surface invasion and mucosal inflammation of the host's intestine caused by b. hominis infection, no real documentation of invasion has been proven. studies have shown that hyaluronidase is secreted during the penetration into the host's skin and gut by nematode parasites. hyaluronidase activity in protozoa namely entamoeba hist ...201020358228
an optimum diagnostic test for amoebic liver abscess in endemic areas: are we there yet? 201021381570
[failure to offer parasitology screening to vulnerable migrants in france: epidemiology and consequences.]the "consultations de diagnostic et d'orientation" (cdo), created in 1998 by the paris health department, are medical consultations for vulnerable populations, which are held in municipal clinics, free of charge. more than two-thirds of cdo patients come from africa. our study was designed to assess and analyze whether these clinics offered consulting migrants screening for intestinal parasitic and schistosoma haematobium infections.material and methodsthis retrospective study included all immig ...201021320812
infectious diarrhea: cellular and molecular mechanisms.diarrhea caused by enteric infections is a major factor in morbidity and mortality worldwide. an estimated 2-4 billion episodes of infectious diarrhea occur each year and are especially prevalent in infants. this review highlights the cellular and molecular mechanisms underlying diarrhea associated with the three classes of infectious agents, i.e., bacteria, viruses and parasites. several bacterial pathogens have been chosen as model organisms, including vibrio cholerae as a classical example of ...201021327112
intestinal parasites infections in hospitalized aids patients in kinshasa, democratic republic of congo.to determine the prevalence and the species spectrum of intestinal parasites (ip) involved in hospitalized aids patients, a prospective observational and cross-sectional study was carried out in the four main hospitals in kinshasa, democratic republic of the congo. from november 2006 through september 2007, a single stool sample was collected from 175 hospitalized aids patients older than 15 years. parasites were detected by light microscopy, including ziehl-neelsen, fungi-fluor, modified trichr ...201021275238
frequency of intestinal parasitic infection among children in hadhramout governorate (yemen).six hundred children from urban and rural regions of hadhramout governorate were examined targeted for the detection of intestinal parasites during the year 2009. the main infective parasites prevailed in children were gardia lamblia (19.17%), entamoeba histolytica (16.83%), ascaris lumbricoides (15.83%), trichuris trichiura (2.33%), hymenolepis nana (2.33%), taenia saginata (1.50%) and schistosoma mansoni (0.67%). besides, infections were accompanied by different symptoms as diarrhea (43.5%), a ...201021246955
involvement of src family tyrosine kinase in apoptosis of human neutrophils induced by protozoan parasite entamoeba histolytica.tyrosine kinases are one of the most important regulators for intracellular signal transduction related to inflammatory responses. however, there are no reports describing the effects of tyrosine kinases on neutrophil apoptosis induced by entamoeba histolytica. in this study, isolated human neutrophils from peripheral blood were incubated with live trophozoites in the presence or absence of tyrosine kinase inhibitors. entamoeba-induced receptor shedding of cd16 and ps externalization in neutroph ...201021234229
epidemiology and control of schistosomiasis and other intestinal parasitic infections among school children in three rural villages of south saint lucia.the purpose of this study was to determine the epidemiology of parasitic infections and the efficacy of treatment among school children in rural villages of south saint lucia.201021178216
development of a negative selectable marker for entamoeba histolytica.entamoeba histolytica is the causative agent of amebiasis and infects up to 10% of the world's population. the molecular techniques that have enabled the up- and down-regulation of gene expression rely on the transfection of stably maintained plasmids. while these have increased our understanding of entamoeba virulence factors, the capacity to integrate exogenous dna into genome, which would allow reverse genetics experiments, would be a significant advantage in the study of this parasite. the c ...201021189470
3d active meshes: fast discrete deformable models for cell tracking in 3d time-lapse microscopy.variational deformable models have proven over the past decades a high efficiency for segmentation and tracking in 2d sequences. yet, their application to 3d time-lapse images has been hampered by discretization issues, heavy computational loads and lack of proper user visualization and interaction, limiting their use for routine analysis of large data-sets. we propose here to address these limitations by reformulating the problem entirely in the discrete domain using 3d active meshes, which exp ...201021193379
intestinal parasites in immigrants in the city of naples (southern italy).the present study was aimed at carrying out a cross-sectional copromicroscopic survey of helminths and intestinal protozoa in immigrants in naples (southern italy). between october 2008 and november 2009, a total of 514 immigrants were tested comparing the flotac dual technique and the ethyl acetate concentration technique. combined results of the two techniques served as a diagnostic 'gold' standard and revealed an overall prevalence of parasitic infections of 61.9% (318/514). the ethyl acetate ...201021195044
epigenetics in the unicellular parasite entamoeba histolytica.amoebiasis is a serious infectious disease that is caused by the unicellular parasite, entamoeba histolytica. this parasite is mainly found in developing countries, and are named owing to its ability to destroy tissues. the molecular mechanisms that regulate the virulence of this parasite are not well understood. in recent years, an increasing interest in the epigenetic regulation of the parasite's virulence has emerged. in this article, an overview of our current knowledge about the role of dna ...201021198420
effect of phosphatidylcholine-cholesterol liposomes on entamoeba histolytica virulence.trophozoites of entamoeba histolytica hm-1:imss become less virulent after long-term maintenance in axenic cultures. the factors responsible for the loss of virulence during in vitro cultivation remain unclear. however, it is known that in vitro cultivation of amoeba in culture medium supplemented with cholesterol restores their virulence. in this study, we analyzed the effect of adding phosphatidylcholine-cholesterol (pc-chol) liposomes to the culture medium and evaluated the effect of this lip ...201021164568
biophysical characterization of entamoeba histolytica phosphoserine aminotransferase (ehpsat): role of cofactor and domains in stability and subunit assembly.we investigated the role of the cofactor plp and its binding domain in stability and subunit assembly of phosphoserine aminotransferase (ehpsat) from an enteric human parasite entamoeba histolytica. presence of cofactor influences the tertiary structure of ehpsat because of the significant differences in the tryptophan microenvironment and proteolytic pattern of holo- and apo-enzyme. however, the cofactor does not influence the secondary structure of the enzyme. stability of the protein is signi ...201021161522
prevalence of intestinal parasites among school children in northern districts of west bank-palestine.to assess the prevalence of intestinal parasite infections in northern districts of west bank, palestine and to determine associated sociodemographic factors.201021073639
epidermal cyst infected by entamoeba histolytica in a patient with no past history of intestinal amebiasis. 201021091686
cd4+ and cd8+ t cell- and il-17-mediated protection against entamoeba histolytica induced by a recombinant vaccine.amebiasis in the murine model can be prevented by vaccination with the gal/galnac lectin through a t cell-dependent mechanism. in this work we further decipher the mechanism of this protection. mice vaccinated with the recombinant "leca" fragment of the gal/galnac lectin with alum were capable of transferring protection to naïve recipients by both cd4+ t cells and surprisingly cd8+ t cells. we then examined the cytokine profile of these cells. cd4+ t cells from pbmc of leca-alum vaccinated mice ...201021095257
calmodulin-like protein from entamoeba histolytica: solution structure and calcium-binding properties of a partially folded protein.the mechanism of ca(2+)-signaling in the protozoan parasite entamoeba histolytica is yet to be understood as many of the key regulators are still to be identified. e. histolytica encodes a number of multi-ef-hand ca(2+)-binding proteins (ehcabps). functionally only one of these molecules, ehcabp1, has been characterized to date. the calmodulin-like protein from e. histolytica (abbreviated as ehcam or ehcabp3) is a 17.23 kda monomeric protein that shows maximum sequence identity with heterologous ...201021114322
n-acetyl-d-glucosaminylphosphatidylinositol de-n-acetylase from entamoeba histolytica: metal alters catalytic rates but not substrate affinity.pig-l/gpi12 proteins are endoplasmic reticulum-resident membrane proteins involved in the second step of glycosylphosphatidylinositol anchor biosynthesis in eukaryotes. we show that the entamoeba histolytica pig-l protein is optimally active in the acidic ph range. the enzyme has an intrinsic low level of de-n-acetylase activity in the absence of metal and is significantly stimulated by divalent cations. metal binding induces a large conformational change in the protein that appears to improve c ...201021118807
leptin signaling in intestinal epithelium mediates resistance to enteric infection by entamoeba histolytica.leptin is an adipocytokine that links nutrition to immunity. previous observation that a genetic polymorphism in the leptin receptor affected susceptibility to entamoeba histolytica infection led to the hypothesis that leptin signaling has a protective role during intestinal amebic infection. in this study we show that mice lacking the functional leptin receptor developed devastating mucosal destruction after e. histolytica infection. bone marrow chimera experiments demonstrated that leptin rece ...201021124310
prevalence of intestinal parasitic infections among hiv patients in benin city, nigeria.this study was carried out to determine the presence of intestinal parasites and their correlation with cd4(+) t-cell counts and demographics among human immunodeficiency virus (hiv)-positive patients in benin city, nigeria. stool specimens from 2,000 hiv-positive patients and 500 controls (hiv-negative individuals) were examined for ova, cysts, or parasites, using standard procedures. in addition, patient's blood samples were analyzed for cd4 counts by flow cytometry. an overall prevalence rate ...201021483561
etiology of childhood diarrhea in the northeast of brazil: significant emergent diarrheal pathogens.in a study conducted in joão pessoa, northeast of brazil, 2344 escherichia coli isolated from 290 infants with diarrhea and 290 healthy matched controls were analyzed for virulence traits. enteroaggregative e. coli (eaec) was the most prevalent pathogen associated to acute diarrhea. based on the results of colony blot hybridization, serotyping, and hep-2 cell adherence assays, strains were separated in categories as typical enteropathogenic e. coli (epec) (1.7%), atypical epec (a-epec) (9.3%), e ...201018508227
microscopic diagnosis of sodium acetate-acetic acid-formalin-fixed stool samples for helminths and intestinal protozoa: a comparison among european reference laboratories.the present study aimed to compare the diagnostic performance of different european reference laboratories in diagnosing helminths and intestinal protozoa, using an ether-concentration method applied to sodium acetate-acetic acid-formalin (saf)-preserved faecal samples. in total, 102 stool specimens were analysed during a cross-sectional parasitological survey in urban farming communities in côte d'ivoire. five saf-preserved faecal samples were prepared from each specimen and forwarded to the pa ...201019456836
evaluation of the antiprotozoal activity of neo-clerodane type diterpenes from salvia polystachya against entamoeba histolytica and giardia lamblia.chia (salvia polystachya ort., lamiaceae) is frequently used in mexican traditional medicine to treat dysentery. in this study the main neo-clerodane diterpenes (polystachynes a, b and d, as well as linearolactone) were isolated from the aerial parts of chia, and their antiprotozoal activities toward entamoeba histolytica and giardia lamblia trophozoites were evaluated in vitro. linearolactone was the most potent antiamoebic and antigiardial compound with ic(50) values of 22.9 microm for e. hist ...201019610033
pathema: a clade-specific bioinformatics resource center for pathogen research.pathema (http://pathema.jcvi.org) is one of the eight bioinformatics resource centers (brcs) funded by the national institute of allergy and infectious disease (niaid) designed to serve as a core resource for the bio-defense and infectious disease research community. pathema strives to support basic research and accelerate scientific progress for understanding, detecting, diagnosing and treating an established set of six target niaid category a-c pathogens: category a priority pathogens; bacillu ...201019843611
epigenetic transcriptional gene silencing in entamoeba histolytica: insight into histone and chromatin modifications.we have previously discovered a unique mechanism of epigenetic transcriptional gene silencing in the entamoeba histolytica trophozoites of strain hm-1:imss that resulted in the persistent downregulation of the amoebapore a (ap-a) gene, and that could be successfully applied to silence other virulence genes (cpa5, lgl1). in order to understand how the silencing is maintained throughout generations, we analysed whether modifications occurred at the chromatin level. chromatin immunoprecipitation as ...201019849886
entamoeba histolytica and e. dispar infections in captive macaques (macaca fascicularis) in the philippines.entamoeba histolytica is a protozoan parasite that infects man and animals. this parasite has a global distribution and the disease it causes is usually characterized by diarrhea. in order to detect the parasite, it is necessary to differentiate it from entamoeba dispar. e. dispar appears morphologically similar to e. histolytica but does not cause disease and tissue invasion. this study reports on the prevalence of e. histolytica and e. dispar among captive macaques in a primate facility in the ...201019862480
crystal structure of the aspartyl-trna synthetase from entamoeba histolytica.the crystal structure of the aspartyl-trna synthetase from the eukaryotic parasite entamoeba histolytica has been determined at 2.8aresolution. relative to homologous sequences, the e. histolytica protein contains a 43-residue insertion between the n-terminal anticodon binding domain and the c-terminal catalytic domain. the present structure reveals that this insertion extends an arm of the hinge region that has previously been shown to mediate interaction of aspartyl-trna synthetase with the co ...201019874856
identification of an avirulent entamoeba histolytica strain with unique trna-linked short tandem repeat markers.highly polymorphic, non-coding short tandem repeats (str) are scattered between the trna genes in entamoeba histolytica in a unique tandemly arrayed organization. str markers that correlate with the virulence of individual e. histolytica strains have recently been reported. here we evaluated the usefulness of trna-linked str loci as genetic markers in identifying virulent and avirulent strains of e. histolytica from 37 japanese e. histolytica samples (12 diarrheic/dysenteric, 20 amebic liver abs ...201019895903
histomonas meleagridis possesses three alpha-actinins immunogenic to its hosts.histomonas meleagridis is a protozoan parasite known to cause histomonosis (syn. typhlohepatitis) in poultry. due to the economic losses which the disease entails, there is an urgency to understanding its pathogenesis. in the present investigation, three partial cdna sequences encoding heterogenic alpha-actinins previously identified for h. meleagridis were completed and characterized. these three h. meleagridis alpha-actinin isoforms were named alpha-actinin1, alpha-actinin2, and alpha-actinin3 ...201019896981
localization of phosphatidylinositol (3,4,5)-trisphosphate to phagosomes in entamoeba histolytica achieved using glutathione s-transferase- and green fluorescent protein-tagged lipid biosensors.entamoeba histolytica is an intestinal protozoan parasite that causes amoebic dysentery and liver abscess. phagocytosis by the parasite is a critical virulence process, since it is a prerequisite for tissue invasion and establishment of chronic infection. while the roles of many of the proteins that regulate phagocytosis-related signaling events in e. histolytica have been characterized, the functions of lipids in this cellular process remain largely unknown in this parasite. in other systems, p ...201019901063
cytotoxic effect of amide derivatives of trifluoromethionine against the enteric protozoan parasite entamoeba histolytica.amoebiasis, caused by infection with the enteric protist entamoeba histolytica, is one of the major parasitic diseases. although metronidazole and its derivatives are currently employed in therapy, the paucity of effective drugs and potential clinical resistance necessitate the development of a novel drug. trifluoromethionine (tfm) is a promising lead compound for antiamoebic drugs. to potentiate the antiamoebic effect of tfm, we synthesised various amide derivatives of tfm and evaluated their c ...201019910163
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