| identification and partial characterization of three chitinase forms in entamoeba invadens with emphasis on their inhibition by allosamidin. | three chitinase forms were identified in entamoeba invadens cysts following fractionation of a soluble fraction by anionic exchange, size exclusion and hydroxyapatite adsorption chromatographies. the enzymes, named here as a, b and b', showed molecular weights of 64, 33.4 and 33.4 kda, respectively, as measured by gel filtration. comparison of their levels of specific activity in partially purified samples revealed chitinase a as the major species. chitinase b' was a minor component of the chiti ... | 1996 | 8836440 |
| entamoeba invadens: characterization of cysteine proteinases. | cysteine proteinases have a number of important functions in the life cycle of protozoan parasites. based on our previous studies demonstrating the role of cysteine proteinases in invasion by entamoeba histolytica, we evaluated the cysteine proteinases of e. invadens, a related protozoan which causes invasive disease of reptiles. e. invadens readily encysts in axenic culture and provides a model to investigate the role of cysteine proteinases in encystation. broad bands of approximately 130-230, ... | 1996 | 8888735 |
| an axenic method of d-[u-14c]glucose incorporation into trophozoites from entamoeba invadens. | | 1996 | 8895967 |
| detection, purification and partial characterization of beta-amylase from trophozoites of entamoeba invadens. | trophozoites of entamoeba invadens were able to ingest glucopolysaccharides and metabolize them. an activity capable of degrading these substrates was purified to apparent homogeneity. the enzyme was identified as beta-amylase (alpha-1,4-d-glucan maltohydrolase ec 3.2.1.2): it was active against glycogen, amylose and amylopectin in a ratio of 100:198:133 and was also able to attack linear alpha-1,4-glucooligosaccharides with more than three glucose moieties. all degradation experiments yielded m ... | 1996 | 9027750 |
| proteasome function is required for encystation of entamoeba invadens. | | 1997 | 9033045 |
| entamoeba invadens differentiation and entamoeba histolytica cyst-like formation induced by co2. | | 1997 | 9033049 |
| cloning and expression of chitinases of entamoebae. | entamoeba histolytica (eh) and entamoeba dispar (ed) are protozoan parasites that infect hundreds of millions of persons. in the colonic lumen, amebae form chitin-walled cysts, the infectious stage of the parasite. entamoeba invadens (ei), which infects reptiles and is a model for amebic encystation, produces chitin synthase and chitinase during encystation. ei cysts formation is blocked by the chitinase-inhibitor allosamidin. here molecular cloning techniques were used to identify homologous ge ... | 1997 | 9106188 |
| cell-surface carbohydrates of entamoeba invadens. | cell-surface carbohydrates of entamoeba invadens trophozoites were analyzed using (a) a panel of highly purified lectins specific for molecules containing n-acetylglucosamine or sialic acid, n-acetylgalactosamine, galactose, mannose-like residues, and fucose; (b) escherichia coli k-12 with mannose-sensitive fimbria; (c) enzymatic digestion; and (d) scanning electron microscopy. the presence of galactose (d-gal) and n-acetylgalactosamine (d-galnac) was detected in the amoeba. previous trypsinizat ... | 1997 | 9342747 |
| ecto-nucleotide triphosphatase activity in pathogenic and non-pathogenic entamoeba: protection from the cytotoxic effects of extracellular atp. | the nucleotide triphosphatase (ntpase) activity of entamoeba species and of entamoeba histolytica strains, was compared. in all cases, with the exception of entamoeba moshkovskii, the enzyme was activated by ca2+ and not by mg2+ and preferentially hydrolysed utp with decreasing activity for atp and gtp. the ntpase activity was associated with both the intracellular and the plasma membrane sulphonylbenzoyl-adenosine (fsba) of trophozoites in which the atp-site was facing externally, as shown by f ... | 1997 | 9670549 |
| crithidia fasciculata induces encystation of entamoeba invadens in a galactose-dependent manner. | the ability of the flagellate crithidia fasciculata to induce encystation of the reptile pathogen, entamoeba invadens, was studied in vitro. a specific ratio of flagellate to amoeba was required; both live and heat-killed c. fasciculata induced amoebic encystation. the interaction between the crithidia and entamoeba cells was found to be galactose-mediated because the addition of galactose to the culture medium, or the pretreatment of the flagellate with galactosidase, eliminated its ability to ... | 1998 | 9714198 |
| system of 14c-glucose incorporation in axenic cultures of entamoeba invadens: ip-1 strain. | it has been described that the walls of the amebic cysts from entamoeba invadens are composed mainly of chitin, a polysaccharide of amino-sugars. it is also known that the synthesis of this polysaccharide is closely related to the degradation of the intracellular glycogen in this organism. nevertheless, it is not known whether the intracellular glycogen is really the source of the glucose requirements for the synthesis of the cell wall. | 1998 | 9775455 |
| entamoeba invadens: reversible effects of aphidicolin on the growth and encystation. | | 1998 | 9806876 |
| chitinase secretion by encysting entamoeba invadens and transfected entamoeba histolytica trophozoites: localization of secretory vesicles, endoplasmic reticulum, and golgi apparatus. | entamoeba histolytica, the protozoan parasite that phagocytoses bacteria and host cells, has a vesicle/vacuole-filled cytosol like that of macrophages. in contrast, the infectious cyst form has four nuclei and a chitin wall. here, anti-chitinase antibodies identified hundreds of small secretory vesicles in encysting e. invadens parasites and in e. histolytica trophozoites overexpressing chitinase under an actin gene promoter. abundant small secretory vesicles were also identified with antibodies ... | 1999 | 10338523 |
| congo red effect on cyst viability and cell wall structure of encysting. entamoeba invadens. | the cell wall of entamoeba invadens cysts is composed of chitin microfibrils as the main structural component. it has been demonstrated in yeast that the chitin cell wall assembly is altered by dyes such as congo red (cr) and calcofluor. | 1999 | 10372443 |
| dna polymerase activity in encysting entamoeba invadens. | using an axenic encystation system of entamoeba invadens as a model for e. histolytica encystation, we examined the level of dna polymerase activity in e. invadens during encystation induced in vitro. we first characterized the dna polymerase activity of trophozoites of e. invadens, comparing it with that of e. histolytica, and found that the activity of e. invadens was lower than that of e. histolytica at ph 2, 4, and 6 and was higher at ph 8 and 10. the activity of e. invadens was completely i ... | 1999 | 10382613 |
| regulation of entamoeba invadens encystation and gene expression with galactose and n-acetylglucosamine. | encystation of entamoeba invadens parasites is prevented by the presence of free galactose or n-acetylglucosamine in the encystation medium. galactose prevents the formation of amoeba cellular aggregates which develop during the early phase of encystation, suggesting the presence of functional cell surface galactose-binding molecules, whereas n-acetylglucosamine allows aggregation to occur and prevents cyst formation at a later point. while studying sugar inhibition of amoeba encystation, it was ... | 1999 | 10477177 |
| proteasome-dependent cyst formation and stage-specific ubiquitin mrna accumulation in entamoeba invadens. | proteases play an important role in the pathogenic mechanisms and differentiation events of protozoan parasites; the proteasome/ubiquitin system is essential for maintaining the differentiation state of many cell types. a single input of the specific inhibitor of proteasomes, lactacystin, prevented encystation of the protozoan parasite entameoba invadens, whereas a cysteine protease inhibitor, e64, only delayed encystation. the ameba target of lactacystin was purified and it displayed the featur ... | 1999 | 10491138 |
| inhibition of encystation of entamoeba invadens by aphidicolin. | effects of aphidicolin, a specific inhibitor of eukaryotic nuclear replicative dna polymerases, on the growth and encystation of a reptilian parasitic protozoan entamoeba invadens were evaluated. aphidicolin blocked the growth of axenic e. invadens strain ip-1 in a dose-dependent manner. encystation induced by the glucose depletion and osmotic pressure was also inhibited by aphidicolin. the inhibition was almost complete when trophozoites were treated with the drug before being transferred to en ... | 1998 | 10622628 |
| appearance of a stage-specific immunodominant glycoprotein in encysting entamoeba invadens. | the appearance of cyst-specific proteins in encysting entamoeba invadens and their immunogenicity were examined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting using an axenic encystation system in vitro. a rabbit antiserum against trophozoites of e. invadens reacted with a number of proteins of cysts after 1-4 days of incubation. thus, a number of cyst proteins remained antigenically unchanged as common antigens of the two forms after transformation from trophozo ... | 2000 | 10669142 |
| inter- and intra-strain variation in the 5.8s ribosomal rna and internal transcribed spacer sequences of entamoeba histolytica and comparison with entamoeba dispar, entamoeba moshkovskii and entamoeba invadens. | the ribosomal rna genes in entamoeba histolytica are located on circular dna molecules in about 200 copies per genome equivalent. nucleotide sequence analysis of the 5.8s rrna gene and the flanking internal transcribed spacers was carried out to determine the degree of sequence divergence in the multiple rrna gene copies of a given strain; amongst three different e. histolytica strains (hm-1:imss, rahman and hk-9); and amongst four species of entamoeba (entamoeba histolytica, entamoeba dispar, e ... | 2000 | 10856506 |
| the most abundant glycoprotein of amebic cyst walls (jacob) is a lectin with five cys-rich, chitin-binding domains. | the infectious stage of amebae is the chitin-walled cyst, which is resistant to stomach acids. in this study an extraordinarily abundant, encystation-specific glycoprotein (jacob) was identified on two-dimensional protein gels of cyst walls purified from entamoeba invadens. jacob, which was acidic and had an apparent molecular mass of approximately 100 kda, contained sugars that bound to concanavalin a and ricin. the jacob gene encoded a 45-kda protein with a ladder-like series of five cys-rich ... | 2000 | 10858239 |
| effect of dinitroaniline herbicides on the growth of entamoeba histolytica. | the effect of the dinitroaniline herbicides oryzalin and trifluralin on the growth of entamoeba histolytica was examined. oryzalin inhibited the growth of e. histolytica strain hm-1:imss. trifluralin was less effective than oryzalin for this parasite. entamoeba histolytica was more resistant to these dinitroanilines than other parasitic protozoa examined so far, including leishmania spp., trypanosoma brucei, plasmodium falciparum, toxoplasma gondii, and cryptosporidium parvum. colchicine, a pote ... | 2000 | 10864261 |
| effect of cytochalasin d on the growth, encystation, and multinucleation of entamoeba invadens. | the effect of cytochalasin d, a specific inhibitor of microfilaments, on the growth, encystation, and multinucleation of entamoeba invadens was examined. cytochalasin d blocked the growth of axenic e. invadens strain ip-1 in a dose-dependent manner, which suggests that the drug is effective against this species of entamoeba as well as against e. histolytica strain hm1: imss as previously demonstrated. encystation of e. invadens as induced in vitro was also inhibited by cytochalasin d. this is th ... | 2000 | 10935912 |
| effect of the antitubulin drug oryzalin on the encystation of entamoeba invadens. | we have recently demonstrated that the antimicrotubule drug oryzalin inhibits the growth of entamoeba invadens as well as e. histolytica, the former being more resistant to the drug than the latter, and that effective doses of oryzalin are higher for entamoeba than for the other parasitic protozoa examined thus far. the aim of the present study was to examine the effect of oryzalin on the encystation of e. invadens using an axenic encystation system in vitro. oryzalin inhibited the encystation o ... | 2000 | 10952260 |
| responses of entamoeba invadens to heat shock and encystation are related. | an entamoeba invadens gene encoding a homologue of bip/grp78, a 70-kda heat shock protein or chaperonin was cloned. the predicted e. invadens bip contained an atp-binding site, a substrate-recognition domain, and a carboxy-terminal kdel-peptide. messenger rnas of e. invadens for bip, for a 70-kda heat shock cognate, for a cyst wall glycoprotein (jacob), and for chitinase were all induced by heat shock and by encystation medium. the presence of jacob in heat-shocked amebae was confirmed by confoc ... | 2000 | 11001149 |
| entamoeba invadens: protein kinase c inhibitors block the growth and encystation. | | 2000 | 11038313 |
| involvement of signaling through protein kinase c and phosphatidylinositol 3-kinase in the encystation of entamoeba invadens. | | 2000 | 11070276 |
| involvement of serine proteinases during encystation of entamoeba invadens. | | 2000 | 11070277 |
| comparative study of entamoeba invadens differentiation in three different axenic encystation media. | | 2000 | 11070278 |
| incorporation of 14c-glucose into cytoplasmic glycogen from entamoeba invadens ip-1 strain. | | 2000 | 11070280 |
| possible inhibition of entamoeba invadens encystation by castela texana. | | 2000 | 11070281 |
| effect of agents that modify camp levels on growth and differentiation of entamoeba invadens. | | 2000 | 11070282 |
| sequential changes occurring on the surface of entamoeba invadens during encystation observed by scanning electron microscopy. | | 2000 | 11070283 |
| the cell cycle of entamoeba invadens during vegetative growth and differentiation. | the cell division cycle of entamoeba invadens was studied during vegetative growth of trophozoites and during their differentiation into cysts. during vegetative growth of trophozoites, it was observed that dna synthesis typically continued after one genome content had been duplicated. during encystation, dna synthesis was arrested after 4n genome content had been synthesised. using multi-parameter flow cytometry, the light scattering properties of cysts and trophozoites were studied. the cytopl ... | 2001 | 11223134 |
| a role for a galactose lectin and its ligands during encystment of entamoeba. | in the life cycle of entamoeba parasites alternate between the colon-dwelling trophozoite and the infectious cyst forms. the physiologic stimuli that trigger differentiation of trophozoites into cysts remain undefined. on the surface of the human-infecting entamoeba, parasites express a galactose/n-acetylgatactosamine (gal/galnac)-binding lectin, which plays demonstrated roles in contact-dependent lysis of target cells and resistance to host complement. using a reptilian parasite, entamoeba inva ... | 2001 | 11249188 |
| effect of jasplakinolide on the growth, encystation, and actin cytoskeleton of entamoeba histolytica and entamoeba invadens. | the effect of jasplakinolide. an actin-polymerizing and filament-stabilizing drug, on the growth, encystation, and actin cytoskeleton of entamoeba histolytica and entamoeba invadens was examined. jasplakinolide inhibited the growth of e. histolytica strain hm-1:imss and e. invadens strain ip-1 in a concentration-dependent manner, the latter being more resistant to the drug. the inhibitory effect of jasplakinolide on the growth of e. histolytica trophozoites was reversed by removal of the drug af ... | 2001 | 11318572 |
| inhibition of encystation of entamoeba invadens by wortmannin. | using an axenic encystation system in vitro, we examined the effect of wortmannin, a potent inhibitor of phosphatidylinositol 3-kinase (pi 3-kinase), which is a signaling molecule responsible for numerous cellular responses, on the encystation of entamoeba invadens. wortmannin inhibited both encystation and growth of e. invadens strain ip-1 in a dose-dependent manner, the former being more resistant to the drug than the latter. there was little decrease in the number of trophozoites after 3 days ... | 2001 | 11403379 |
| modifications of kohn's chlorazol black e staining and wheatley's trichrome staining for temporary wet mount and permanent preparation of entamoeba histolytica. | preparation of stained smears of entamoeba histolytica has several drawbacks. we therefore tried to simplify the staining procedures by modifing kohn's chlorazol black e staining and wheatley's trichrome staining techniques. trophozoites and cysts of axenically cultured e. histolytica and entamoeba invadens, respectively, and trophozoites and cysts of e. histolytica in stools of patients were used. karyosomes and peripheral chromatin of nuclei and chromatoid bodies became distinctly visible afte ... | 2001 | 11426739 |
| entamoeba invadens: enhancement of excystation and metacystic development by cytochalasin d. | effects of three actin-modifying drugs, cytochalasin d, latrunculin a, and jasplakinolide, on the excystation and metacystic development in vitro of entamoeba invadens were examined by transfer of the cysts to growth medium with the drugs. cytochalasin d unexpectedly increased the number of metacystic amoebae of e. invadens strain ip-1 during incubation. metacystic development, which was determined by the number of nuclei of metacystic amoebae, was faster in the culture with cytochalasin d than ... | 2001 | 11527437 |
| effect of calcium antagonists, calcium channel blockers and calmodulin inhibitors on the growth and encystation of entamoeba histolytica and e. invadens. | the effects of calcium antagonists, calcium channel blockers, and calmodulin inhibitors on the growth of entamoeba histolytica and the growth and encystation of entamoeba invadens were examined. calcium chelators ethyleneglycol bis (beta-aminoethyl ether)-n,n'-tetraacetate (egta) and ethylene-diaminetetraacetate (edta) inhibited the growth of both entamoeba and also the encystation of e. invadens in a dose-dependent manner, with edta being more effective than egta. a putative antagonist of intra ... | 2001 | 11688889 |
| the enteric parasite entamoeba uses an autocrine catecholamine system during differentiation into the infectious cyst stage. | enteric amoebae of the genus entamoeba travel from host to host in an encysted form. we previously showed that in vitro cyst development of entamoeba invadens requires the addition of defined amounts of multivalent galactose-terminated molecules, such as mucin, to the cultures. the amoeba surface lectin that binds mucin is presumed to convey transmembrane signals when clustered by the ligand, but the signaling molecules that function downstream of the lectin are not known. we report here that en ... | 2002 | 11779874 |
| amebiasis in four ball pythons, python reginus. | between september 13th and november 18th in 1999, four ball pythons, python reginus kept in the same display, showed anorexia and died one after another. at necropsy, all four snakes had severe hemorrhagic colitis. microscopically, all snakes had severe necrotizing hemorrhagic colitis, in association with ameba-like protozoa. some of the protozoa had macrophage-like morphology and others formed protozoal cysts with thickened walls. these protozoa were distributed throughout the wall in the large ... | 2001 | 11789622 |
| entamoeba histolytica lectins contain unique 6-cys or 8-cys chitin-binding domains. | the jacob lectin, the most abundant glycoprotein in the cyst wall of entamoeba invadens, contains five unique 6-cys chitin-binding domains (cbds). we identified entamoeba histolytica and entamoeba dispar genes encoding jacob homologues, each of which contains two predicted 6-cys cbds. a unique 8-cys cbd was found at the n termini of the e. histolytica chitinase and three other predicted lectins, called jessie 1 to jessie 3. the cbds of four e. histolytica lectins (jacob, chitinase, and jessies 2 ... | 2002 | 12011021 |
| effect of proteasome inhibitors on the growth, encystation, and excystation of entamoeba histolytica and entamoeba invadens. | the effect of three proteasome inhibitors, lactacystin, clasto-lactacystin beta-lactone, and mg-132, on the growth, encystation, and excystation of entamoeba histolytica and entamoeba invadens was examined. all of these drugs blocked e. histolytica growth in a concentration-dependent manner; lactacystin was most potent for the inhibition and mg-132 showed the inhibitory effect only at higher concentrations. e. invadens was more resistant to these drugs than e. histolytica. encystation of e. inva ... | 2002 | 12049464 |
| possible role of calcium ions, calcium channels and calmodulin in excystation and metacystic development of entamoeba invadens. | the effect of calcium ions (ca(2+)) and calmodulin (cam) on the excystation and metacystic development of entamoeba invadens was examined by transfer of cysts to a growth medium containing calcium antagonists and cam inhibitors. excystation, which was assessed by counting the number of metacystic amoebae after induction of excystation, was inhibited by the calcium chelators ethyleneglycol bis (beta-aminoethyl ether)- n,n'-tetraacetate (egta) and ethylene-diaminetetraacetate (edta), with edta bei ... | 2002 | 12172816 |
| nature of the packing of ribosomes within chromatoid bodies. | optical fourier transformns, made of electron mnicrographs of the crystalline array of ribonucleoprotein known as chromatoid bodies of entamoeba invadens, have been interpreted as the transforms of a helix of 12 nodes in five turns. a model shows that this helix may be built of spheres 180 angstroms in diameter, placed at a radius of 150 angstroms. the optical transform of the model is very similar to the transform of the original electron micrograph. | 1966 | 12325350 |
| inhibition of excystation and metacystic development of entamoeba invadens by the dinitroaniline herbicide oryzalin. | the effect of oryzalin on excystation and metacystic development of entamoeba invadens strain ip-1 was examined by transfer of cysts to a growth medium containing the drug. excystation, which was assessed by counting the number of metacystic amoebae after induction of excystation, was inhibited by oryzalin in a concentration-dependent manner. metacystic development, which was determined by the number of nuclei in metacystic amoebae, was also inhibited by oryzalin because the percentage of 4-nucl ... | 2002 | 12435143 |
| biosynthesis of entamoeba histolytica proteophosphoglycan in vitro. | a complex glycoconjugate proteophosphoglycan (ppg) is present on the surface of the pathogenic protozoan parasite entamoeba histolytica but not in the non-pathogenic entamoeba dispar. it is thought to be an important molecule involved in pathogenesis. in order to study its biosynthesis, an in vitro cell-free system was developed. the specificity of the system was demonstrated by various criteria including immunoprecipitation by a specific monoclonal antibody. the in vitro synthesized molecule wa ... | 2003 | 12554078 |
| ehp53, an entamoeba histolytica protein, ancestor of the mammalian tumour suppressor p53. | this paper reports the identification of ehp53, a p53-like entamoeba histolytica protein, which binds to the human p53 dna consensus sequence (oli-p53). monoclonal antibodies against p53 (ab-1 and ab-2) recognized a single 53 kda spot in two-dimensional gels and inhibited the formation of complexes produced by e. histolytica nuclear extracts and oli-p53. additionally, e. histolytica gene promoter sequences with high homology to oli-p53 formed complexes with nuclear proteins that were abolished b ... | 2003 | 12686631 |
| gene discovery in the entamoeba invadens genome. | entamoeba invadens, a parasite of reptiles, is a model for the study of encystation by the human enteric pathogen entamoeba histolytica, because e. invadens form cysts in axenic culture. with approximately 0.5-fold sequence coverage of the genome, we were able to get insights into e. invadens gene and genome features. overall, the e. invadens genome displays many of the features that are emerging from ongoing genome sequencing efforts in e. histolytica. at the nucleotide level the e. invadens ge ... | 2003 | 12798503 |
| entamoeba invadens: inhibition of excystation and metacystic development by aphidicolin. | the effect of aphidicolin, a specific inhibitor of the replicative dna polymerases, on the excystation and metacystic development of entamoeba invadens was examined. the protein profile of metacystic amoebae and their immunogenicity in the presence and absence of aphidicolin were also examined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting. excystation, which was assessed by counting the number of metacystic amoebae after the induction of excystation, was inhibit ... | 2003 | 12810048 |
| involvement of signaling through protein kinase c and phosphatidylinositol 3-kinase in the excystation and metacystic development of entamoeba invadens. | using an axenic excystation system in vitro, we examined the effect of protein kinase c (pkc) and phosphatidylinositol 3-kinase (pi3k), which are signaling molecules responsible for numerous cellular responses, on the excystation and metacystic development of entamoeba invadens. excystation, which was assessed by counting the number of metacystic amoebae after the induction of excystation, was inhibited by the pkc inhibitors staurosporine, chelerythrine chloride and calphostin c in a concentrati ... | 2003 | 12923632 |
| bacteria-free entamoeba invadens. | | 1953 | 13111288 |
| the action of ameobicidal drugs on entamoeba invadens rodhain, 1934 in vitro. | | 1954 | 13166379 |
| the influence of environmental factors on the size of the cysts of entamoeba invadens rodhain, 1934. | | 1954 | 13214907 |
| studies on entamoeba invadens rodhain, 1934, in vitro, and its relationship to some other species of entamoeba. | | 1955 | 13280284 |
| experimental infection of chick embryos with entamoeba invadens. | | 1956 | 13293578 |
| modification and elimination of the bacterial flora in cultures of entamoeba invadens rodhain, 1934. | | 1956 | 13322461 |
| [factors affecting the growth and behaviour of axenic strains of entamoeba invadens rodhain, 1934]. | | 1958 | 13600866 |
| the relationship between entamoeba invadens rodhain and its hosts. | | 1958 | 13605583 |
| the chromatoid body of entamoeba invadens. | | 1958 | 13609637 |
| an electron microscopic study of entamoeba invadens rodhain 1934. | | 1959 | 13663883 |
| an electron-microscopic observation of the "tail" end of entamoeba invadens. | | 1961 | 13787791 |
| the relationship between diameter and virulence of the cysts of entamoeba invadens rodhain. | | 1959 | 13833692 |
| an electron microscopic observation of starch ingestion by entamoeba invadens. | | 1962 | 14003149 |
| a preliminary note on the experimental infection of chick embryos with entamoeba invadens. | | 1955 | 14364354 |
| growth of entamoeba invadens in organotypic cultures of embryonic chick intestine. | | 1961 | 14472093 |
| infectivity and pathogenicity of polyxenic and monoxenic entamoeba invadens to snakes kept at normal and high temperatures and the natural history of reptile amoebiasis. | | 1961 | 14472094 |
| very little intron gain in entamoeba histolytica genes laterally transferred from prokaryotes. | the evolution of spliceosomal introns remains intensely debated. we studied 96 entamoeba histolytica genes previously identified as having been laterally transferred from prokaryotes, which were presumably intronless at the time of transfer. ninety out of the 96 are also present in the reptile parasite entamoeba invadens, indicating lateral transfer before the species' divergence approximately 50 mya. we find only 2 introns, both shared with e. invadens. thus, no intron gains have occurred in ap ... | 2006 | 16847043 |
| ultrastructure of cyst differentiation in parasitic protozoa. | cysts represent a phase in the life cycle of biphasic parasitic protozoa that allow them to survive under adverse environmental conditions. two events are required for the morphological differentiation from trophozoite to cyst and from cyst to trophozoite: the encystation and excystation processes. in this paper, we present a review of the ultrastructure of the encystation and excystation processes in entamoeba invadens, acanthamoeba castellanii, and giardia lamblia. the comparative electron mic ... | 2007 | 17252271 |
| a method for in vitro culture of entamoeba invadens free from bacteria. | | 1951 | 17648531 |
| effects of some environmental factors upon growth and encystation of entamoeba invadens. | | 1962 | 13864243 |
| a ribonucleoprotein inclusion body in entamoeba invadens. | | 1963 | 13966691 |
| a helical structure in ribonucleoprotein bodies of entamoeba invadens. | | 1963 | 14074634 |
| localization of cytoplasmic nucleic acid during growth and encystment of entamoeba invadens. | with a modified color-translating ultraviolet microscope, the distribution of material showing an absorption maximum at 265 mmicro was studied in samples from whole cultures of entamoeba invadens at intervals during growth and from cysts allowed to mature under controlled conditions. absorption by the cytoplasm in general gradually increased as trophozoites approached the period of maximum encystment. in late trophozoites and precystic forms, the absorbing material was concentrated into small bo ... | 1964 | 14128044 |
| nuclear division in entamoeba invadens rodhain, 1934. | | 1964 | 14128123 |
| electrokinetic properties of entamoeba invadens, rodhain 1934. | | 1965 | 14293841 |
| ultrastructural study of entamoeba invadens encystation and excystation. | in the life cycle of entamoeba species, the cyst and all the processes associated to it have been poorly studied. entamoeba invadens, a serpent's parasite, has been commonly accepted as a model for the study of encystation and excystation. here we analyzed through scanning and transmission electron microscopy the in vitro morphological differentiation of both processes. during encystation, the formation of an irregular net of fibrillar material on the surface of precysts was observed. in thin se ... | 2003 | 14690171 |
| different effects of cytochalasins on the growth and differentiation of entamoeba invadens. | the effect of five different cytochalasins on the growth, encystation and excystation of entamoeba invadens was examined. at 10 microm, cytochalasins b, d, e and dihydrocytochalasin b markedly inhibited growth. encystation was inhibited by cytochalasin d at 1 microm but not by other cytochalasins at the same concentration, whereas it was inhibited by 10 microm of cytochalasins b, e and dihydrocytochalasin b as well as cytochalasin d. excystation, which was assessed by counting the number of meta ... | 2004 | 15103555 |
| entamoeba histolytica: ultrastructure of trophozoites recovered from experimental liver lesions. | ultrastructural studies on entamoeba histolytica have been carried out mostly with trophozoites cultured for many years. under these conditions, the availability of nutrients and the absence of environmental stimuli may switch off some phenotypic characteristics of the parasite. as a result, virulence of e. histolytica diminishes with prolonged culture passages, and the ability to form cysts disappears in axenically maintained trophozoites. the present analysis by transmission electron microscop ... | 2004 | 15208036 |
| entamoeba invadens contains the components of a classical adrenergic signaling system. | epinephrine (epi) was previously found to bypass the need for galactose ligands during early steps in the initiation of entamoeba encystment. epinephrine is presumed to act on amoebae through a classical adrenergic signaling pathway that results in the increased production of cyclic adenosine monophosphate (camp). the object of this study was to verify the existence of an adrenergic like pathway and its response to epi in both whole entamoeba trophozoites and purified plasma membrane preparation ... | 2004 | 15383304 |
| encystation in entamoeba invadens. | knowledge of the biology and pathogenesis of the human parasite entamoeba histolytica has been limited by the lack of efficient procedures to induce axenic encystation in the laboratory. however, such methods have been developed for e. invadens, a reptilian parasite, for which encystation can be induced by mechanisms that are as yet poorly defined. this has allowed the analysis of some morphological, physiological and biochemical events that accompany differentiation into cysts. elucidation of t ... | 1993 | 15463765 |
| entamoeba invadens: cysteine protease inhibitors block excystation and metacystic development. | we examined the effects of six cysteine protease inhibitors on the excystation and metacystic development of entamoeba invadens. excystation, which was assessed by counting the number of metacystic amoebae after the induction of excystation, was inhibited by the cysteine protease inhibitors z-phe-ala-dmk and e-64d in a concentration-dependent manner during incubation compared to the controls. neither inhibitor had a significant effect on cyst viability; thus, their inhibitory effects were not du ... | 2004 | 15639136 |
| colonic short-chain fatty acids inhibit encystation of entamoeba invadens. | entamoeba parasites multiply as trophozoites in the layer of mucus that overlies the colonic epithelium. in response to stimuli that are not understood, trophozoites stop multiplying and differentiate into cysts that are released to infect another host. in the colon, entamoeba trophozoites are exposed to the large variety of biochemicals that are carried into or are produced within this organ. the normal bacterial population of the colon releases large amounts of short-chain fatty acids (scfas). ... | 2005 | 15659070 |
| unexpected diversity and differential success of dna transposons in four species of entamoeba protozoans. | we report the first comprehensive analysis of transposable element content in the compact genomes (approximately 20 mb) of four species of entamoeba unicellular protozoans for which draft sequences are now available. entamoeba histolytica and entamoeba dispar, two human parasites, have many retrotransposons, but few dna transposons. in contrast, the reptile parasite entamoeba invadens and the free-living entamoeba moshkovskii contain few long interspersed elements but harbor diverse and recently ... | 2005 | 15901838 |
| entamoeba histolytica: observations on metabolism based on the genome sequence. | the sequencing of the genome of entamoeba histolytica has allowed a reconstruction of its metabolic pathways, many of which are unusual for a eukaryote. based on the genome sequence, it appears that amino acids may play a larger role than previously thought in energy metabolism, with roles in both atp synthesis and nad regeneration. arginine decarboxylase may be involved in survival of e. histolytica during its passage through the stomach. the usual pyrimidine synthesis pathway is absent, but a ... | 2005 | 15955308 |
| entamoeba invadens: restriction of ploidy by colonic short chain fatty acids. | the dna content of entamoeba parasites appears to be regulated by an unusual mechanism. this conclusion, however, was based on experiments that examined parasites grown in media that did not contain short chain fatty acids (scfas) normally found in the colonic lumen. since one of these scfas, butyrate, is known to affect dna replication in eukaryotic cells, we examined the effect of scfas on entamoeba trophozoite dna content. similar to reports from others, we found that entamoeba invadens troph ... | 2005 | 15955313 |
| entamoeba invadens: in vitro axenic encystation with a serum substitute. | the current media for axenic cultivation of entamoeba histolytica and entamoeba invadens are supplemented with bovine or equine serum, which provides several essential nutrients to amoebas. serum has also been considered an essential component in encystation media for e. invadens. a substitute of serum, pacsr has been described as an alternative for growth of e. histolytica and also maintains growth of e. invadens. when pacsr was used instead of serum for encystation of e. invadens the efficienc ... | 2005 | 15955331 |
| effect of artificial gastrointestinal fluids on the excystation and metacystic development of entamoeba invadens. | the effect of artificial gastric fluid (agf), containing 0.5% pepsin and 0.6% hydrochloric acid, ph 1.8, in distilled water, on the excystation and metacystic development of entamoeba invadens was examined. excystation, which was assessed by counting the number of metacystic amoebae after inducing excystation, was enhanced by pretreatment of cysts with agf for 30 to 60 min at 37 degrees c but not 26 degrees c. longer exposure of cysts to agf significantly reduced their viability. significant enh ... | 2006 | 16416121 |
| dna methylation and targeting of line retrotransposons in entamoeba histolytica and entamoeba invadens. | in this study, we have isolated by affinity chromatography, using anti-m5c antibody as a ligand, a dna encoding reverse transcriptase of line retrotransposon (rt line) in both entamoeba invadens and entamoeba histolytica. rt line transcripts were detected in e. histolytica but were absent from e. invadens. the methylation status of genomic copies of e. invadens rt line was confirmed by bisulfite analysis. in contrast, all the genomic copies of the e. histolytica rt line analyzed in this study we ... | 2006 | 16530279 |
| the cyst wall of entamoeba invadens contains chitosan (deacetylated chitin). | the cyst wall of entamoeba invadens (ei), a model for the human pathogen entamoeba histolytica, contains chitin, which is a homopolymer of beta-1, 4-linked n-acetyl-glucosamine (glcnac). in fungi and in bacteria that make nodulation factors, chitin deacetylases make chitosan, which is a mixture of glcnac and glucosamine and so has a positive charge. the activity of an ei chitin deacetylase was revealed by a 3-4-fold increase in released glcnac when deproteinated cyst walls were chemically acetyl ... | 2006 | 16621070 |
| unique posttranslational modifications of chitin-binding lectins of entamoeba invadens cyst walls. | entamoeba histolytica, which causes amebic dysentery and liver abscesses, is spread via chitin-walled cysts. the most abundant protein in the cyst wall of entamoeba invadens, a model for amebic encystation, is a lectin called eijacob1. eijacob1 has five tandemly arrayed, six-cys chitin-binding domains separated by low-complexity ser- and thr-rich spacers. e. histolytica also has numerous predicted jessie lectins and chitinases, which contain a single, n-terminal eight-cys chitin-binding domain. ... | 2006 | 16682461 |
| pcr for the identification and differentiation of histomonas meleagridis, tetratrichomonas gallinarum and blastocystis spp. | in the present investigation pcr assays were developed for the rapid detection and differentiation of two poultry flagellates: histomonas meleagridis and tetratrichomonas gallinarum as well as the protozoan microorganism: blastocystis spp. the nucleotide sequences of the small subunit ribosomal rnas were used for primer construction obtaining fragments which vary in size for each microorganism. the established pcrs were able to detect dna obtained from one microorganism of t. gallinarum and blas ... | 2006 | 16920265 |
| sensing dna methylation in the protozoan parasite entamoeba histolytica. | in the protozoan parasite entamoeba histolytica, 5-methylcytosine (m5c) was found predominantly in repetitive elements. its formation is catalysed by ehmeth, a dna methyltransferase that belongs to the dnmt2 subfamily. here we describe a 32 kda nuclear protein that binds in vitro with higher affinity to the methylated form of a dna encoding a reverse transcriptase of an autonomous non-long-terminal repeat retrotransposon (rt line) compared with the non-methylated rt line. this protein, named e. ... | 2006 | 17059565 |
| entamoeba invadens: the requirement for galactose ligands during encystment. | during periods of stress, trophozoites of entamoeba invadens (strain ip-1) undergo a process of differentiation (encystment) that results in a dormant cyst with a chitin-containing cyst wall. encystment can be induced by resuspension of trophozoites from growth medium into a diluted glucose-free medium (47% lg) containing 5% adult bovine serum (abs). abs is thought to be a source of gal-terminated ligands that are required for high levels of encystment. after resuspension of trophozoites in 47% ... | 2007 | 17442308 |
| the effects of steroids on the in vitro growth of entamoeba invadens. | | 1953 | 17648648 |
| acetylation of the entamoeba histone h4 n-terminal domain is influenced by short-chain fatty acids that enter trophozoites in a ph-dependent manner. | treatment of higher eukaryotic cells with short-chain fatty acids (scfa) such as butyrate causes decreased levels of histone deacetylase (hdac) activity and hyperacetylation of histones, and thereby affects gene expression, cell growth and differentiation. entamoeba parasites encounter high levels of scfa in the host colon, and in vitro these compounds allow trophozoite stage parasites to multiply but prevent their differentiation into infectious cysts. the entamoeba invadens ip-1 histone h4 pro ... | 2008 | 17706222 |
| autophagy during proliferation and encystation in the protozoan parasite entamoeba invadens. | autophagy is one of the three systems responsible for the degradation of cytosolic proteins and organelles. autophagy has been implicated in the stress response to starvation, antigen cross-presentation, the defense against invading bacteria and viruses, differentiation, and development. saccharomyces cerevisiae atg8 and its mammalian ortholog, lc3, play an essential role in autophagy. the intestinal protozoan parasite entamoeba histolytica and a related reptilian species, entamoeba invadens, po ... | 2008 | 17923513 |
| patterns of evolution in the unique trna gene arrays of the genus entamoeba. | genome sequencing of the protistan parasite entamoeba histolytica hm-1:imss revealed that almost all the trna genes are organized into tandem arrays that make up over 10% of the genome. the 25 distinct array units contain up to 5 trna genes each and some also encode the 5s rna. between adjacent genes in array units are complex short tandem repeats (strs) resembling microsatellites. to investigate the origins and evolution of this unique gene organization, we have undertaken a genome survey to de ... | 2008 | 17974548 |
| diphtheroid colitis in a boa constrictor infected with amphibian entamoeba sp. | a female boa (boa constrictor) from a zoological collection was submitted for necropsy after sudden death. prominent pathological findings included a diphtheroid colitis, endoparasitism, focal pneumonia and inclusion bodies typical for inclusion body disease (ibd). in the colon entamoebae were identified, which differed in size and distribution from entamoeba invadens. gene sequence analysis of the 18s ribosomal rna revealed 100% similarity with an entamoeba species from the african bullfrog (py ... | 2008 | 18291588 |