| effects of 2,4-dinitrophenol on trichomonads and entamoeba invadens. | 1. 2,4-dinitrophenol (2,4-dnp) in substrate level concentrations (200 microm-1 mm) temporarily inhibits h2 production by tritrichomonas foetus and trichomonas vaginalis as well as the accumulation of metronidazole, dependent on its reduction by the two trichomonad species and by entamoeba invadens. 2. 2,4-dnp competes for the reducing equivalents which are necessary for h2 production or for the reduction of metronidazole, thereby inhibiting these processes. 2,4-dnp is reduced to 2-amino, 4-nitro ... | 1979 | 45533 |
| [characterization of surface molecules of entamoeba invadens]. | in this paper we studied the externally disposed plasma membrane antigens in entamoeba invadens using the enzymatic iodination technique. sodiumdodecyl-sulfate-polyacrylamide gels of solubilized trophozoite proteins revealed six labeled peaks ranging from 14,000 to 67,000 daltons in gradient slab gels. over 60 percent of the labeled was in the polypeptide of 67,000 daltons. concanavalin a binding to these trophozites induced cell surface coat release consituted by three radioactive bands of 67,0 ... | 1978 | 100067 |
| the surface membrane and cytoplasmic membranes of entamoeba invadens (rodhain 1934)-i. gross chemical and enzymatic properties. | | 1975 | 128433 |
| isolation and characterization of subcellular membranes of entamoeba invadens. | a method is described for the isolation of subcellular membranes of entamoeba invadens. plasma membranes were obtained by rate centrifugation followed by isopycnic centrifugation on a sucrose gradient. intact phagolysosomes floated in a 10% sucrose solution providing a simple technique for isolation. phagolysosomal membranes were collected by isopycnic centrifugation, after lysis of the phagolysosomes. microsomes were obtained by differential centrifugation. membrane fractions were examined by e ... | 1976 | 136451 |
| [effect of glycolysis inhibitors on the uptake of metronidazole by the protozoa tritrichomonas foetus and entamoeba invadens]. | uptake of metronidazole by the anaerobic protozoa, tritichomonas foetus and entamoeba invadens is dependent on the energy metabolism of these organisms. the inhibitors of glycolysis, iodoacetamide and sodium fluoride, inhibit the uptake. an atmosphere of hydrogen eliminates this inhibition in the hydrogenase-containing t. foetus but not in e. invadens which lacks the enzyme. | 1978 | 159096 |
| differentiation of entamoeba: a new medium and optimal conditions for axenic encystation of e. invadens. | nutritional and culturing requirements for efficient axenic encystation of entamoeba invadens have been studied. a simple and reliable axenic encystation medium has been developed. it contains 0.5% tryptic digest of casein, 0.5% yeast extract, and 5% dialyzed serum in 5 mm potassium phosphate, ph 7.0. mass encystation (avg 70%) occurred within 30 hr when axenically growing trophozoites of e. invadens ip-l were transferred to this medium before they entered stationary growth phase. mass encystati ... | 1975 | 163898 |
| immunochemical studies of the surface and cytoplasmic membranes of entamoeba invadens (rodhain 1934). | the antigenic properties of cell fractions prepared from axenically grown entamoeba invadens were investigated using various immunoelectrophoretic methods. all membrane fractions displayed varying degrees of antigenicity, the most predominant being a cytoplasmic light-vesicle fraction. the surface membrane showed the least diversified range of antigenic components and was also the least immunogenic fraction as judged by the reactivity of the antisera produced. using tandem-crossed immunoelectrop ... | 1975 | 172203 |
| the rhabdoviruses of entamoeba histolytica and entamoeba invadens. | rhabdoviruses have been described in plants, arthropods and vertebrates including man. members of the group are of agricultural, veterinary and medical importance. the presence of a rhabdovirus in entamoeba histolytica and entamoeba invadens is the first record of their existence within protozoa. the morphology of this virus is described and its significance discussed, in relation to a possible lysogenic state and pathogenecity of entamoeba species. | 1976 | 178279 |
| entamoeba histolytica and entamoeba invadens: chromium release from labeled human liver cells in culture. | | 1977 | 202477 |
| [ultramicroscopic structure of the cyst wall of entamoeba invadens, e. histolytica and e. coli]. | the ultrastructure of the wall of e. invadens cysts induced in axenic cultures was compared by transmission electron microscopy of thin sections, with that of e. histolytica and e. coli cysts obtained from feces of human asymptomatic carriers. the cyst wall of the three species studied had similar ultrastructural features; in all, the wall was composed mainly by the aggregation of filaments adjacent to the plasma membrane. the cytoplasmic components which might be involved in the synthesis and d ... | 1978 | 211940 |
| [effects of nordihydroguairetic acid and ethanol on the growth of entamoeba invadens]. | the effects of the alcoholic extract (resin) obtained from larrea tridentata, of nordihydroguiaretic acid (ndga) and of ethanol over axenic cultures of entamoeba invadens pz strain were studied. the activity of these substances was demonstrated in growht curves. inocula of 1-3 x 10(5) trophozites by milliliter in culture tubes containing 11 ml of tp-s-1 medium were done, and incubated at 25 degree c. in each experiment the follwoing was done: a) tipical growth curve as a control, b) curve with t ... | 1978 | 211947 |
| clonal growth of entamoeba histolytica and other species of entamoeba in agar. | this is the first description of a method for growing axenized entamoeba histolytica as colonies from single cells in agar suspension. factors affecting the efficiency of colony formation included unknown characteristics of the amebal strain, age of cells used, and the type and concentration of agar employed. colony formation was dependent upon filling deep vessels (culture tubes or tissue culture flasks) with agar, probably to maintain reduced oxygen tension, and upon solidifying the agar rapid ... | 1978 | 216801 |
| [histochemical studies of various enzymes in amoebae of the genus entamoeba: entamoeba histolytica (schaudinn, 1903), entamoeba invadens (rodhain, 1934) and entamoeba moshkovskii (tshalaia, 1941)]. | | 1979 | 225891 |
| [formation of the cell wall during the formation of entamoeba invadens cysts]. | the presence of chitin in the walls of e. invadens cysts has provided a new way to study the process of encystation, since chitin stains intensely in the presence of calcofluor white m2r, a fluroescent dye. with this technique we have observed various stages in the differentiation of trophozoite membrane, then the cyst is formed inside the trophozoite and finally the cyst leaves the trophozoite after partial degradation of trophozoite body. | 1978 | 697474 |
| [composition of the cell wall of entamoeba invadens cysts]. | cyst walls isolated from entamoeba invadens have a microfibrillar structure. the main sugars detected in acid hydrolysates from walls were hexosamines. x-ray diffraction analysis of the cyst walls demonstrated that the only crystalline polymer present was chitin. | 1978 | 697489 |
| [parasites of fresh water turtles in tunisia]. | a survey work during 1974-75 on the parasites of aquatic turtles of tunisia, twenty one specimens (9 males and 12 females) were captured in the watercourses of the northern area of tunisia and dissected in the institut pasteur of tunis. these turtles belong to the species; clemmys caspica var. leprosa and emys orbicularis (l. 1758). the following parasites were recovered from these turtles: trematodes: polystomoides tunisiensis and telorchis temimi (gonzalez and mishra, 1977) and t. solivagus (o ... | 1978 | 756699 |
| uptake of metronidazole and its effect on viability in trichomonads and entamoeba invadens under anaerobic and aerobic conditions. | [(14)c]metronidazole used at the chemotherapeutic concentration of 10 mug/ml is taken up rapidly by the anaerobic protozoa tritrichomonas foetus, trichomonas vaginalis, and entamoeba invadens kept under anaerobic conditions. it can be calculated that within 30 to 60 min the intracellular concentration of the label is 50 to 100 times higher than in the medium. the presence of air markedly suppresses the uptake in the trichomonads and abolishes it in e. invadens. the suppression disappears after a ... | 1976 | 1083712 |
| the mechanism of formation of inhibitor-induced ribosome helices in entamoeba invadens. | helices andaggregates of helices (chromatoid bodies) composed of ribosomelike particles appear in cysts and slow-growing trophozoites of entamoeba invadens. we found that similar helix aggregates were formed abundantly in actively growing e. invadens trophozoites treated with a variety of direct or indirect inhibitors of protein synthesis. the inhibitor-induced helices appeared cytochemically and ultrastructurally identical to those seen in cysts. numerous single helices and small arrays occurre ... | 1975 | 1133115 |
| comparision of the structure and function of polysomal and helical ribosomes from entamoeba invadens. | some structural and functional properties of ribosomes from polysomes and from helix aggregates of entamoeba invadens have been compared by sucrose gradient analysis and assays of in vitro protein synthesis. actively growing trophozoites, lacking helices, presented normal polysome profiles in sucrose gradients. the single large ribosomal helix aggregate (chromoatoid body) of cysts diappeared as the cells were disrupted. gradient profiles of cyst extracts contained predominantly large and small r ... | 1975 | 1133116 |
| epizootic of fatal amebiasis among exhibited snakes: epidemiologic, pathologic, and chemotherapeutic considerations. | an epizootic of reptilian amebiasis seems to have caused the death of 15 to 16 large and valuable captive snakes (boas, pythons, and anacondas) occupying one of 5 large display dioramas in the steinhart aquarium of the california academy of science, golden gate park, san francisco. subsequent review of previous snake deaths in the colony indicated that of 464 snakes that had died since early 1969, 89 snakes had intestinal or hepatic lesions, and 80 of these snakes had pathologic features which i ... | 1975 | 1147335 |
| phospholipids of entamoeba invadens. | | 1975 | 1190798 |
| the surface and cytoplasmic membranes of entamoeba invadens (rodhain 1934)--ii. polypeptide and phospholipid composition. | | 1975 | 1204332 |
| immediate autoproteolysis and new proteinases in entamoeba invadens and entamoeba moshkovskii trophozoites. | we have examined the sodium dodecyl sulfate (sds)-induced autoproteolysis of e. invadens (pz and ip101) and e. moshkovskii (fic and laredo) trophozoite lysates. heat-treated lysates containing parahydroxy-mercuribenzoate (phmb) of all four strains had undegraded protein patterns. unheated phmb-lacking lysates of pz had two (99 and 90 kda) and ip101 lysates had three (45, 99, 90 kda) major proteins, whereas fic and laredo lysates had only one (90 kda). heat-treatment changed the remaining protein ... | 1992 | 1340331 |
| entamoeba motility: dynamics of cytoplasmic streaming, locomotion and translocation of surface-bound particles, and organization of the actin cytoskeleton in entamoeba invadens. | the dynamics of cytoplasmic streaming, retrograde translocation of externally bound particles and locomotion by entamoeba invadens were compared. locomoting amoebae were monopodial, exhibited fountain flow cytoplasmic streaming and translocated externally bound erythrocytes to the rear of cells. the rates of rearward flow of peripheral cytoplasmic vacuoles and of the externally bound particles were equal to the rate of cell forward locomotion. rhodamine-phalloidin staining revealed a distinct co ... | 1992 | 1578401 |
| chitinase activity in encysting entamoeba invadens and its inhibition by allosamidin. | chitinase activity was measured in extracts of entamoeba invadens cells as a function of time of encystation in axenic conditions using 4-mu(ch)3 as substrate. encystment was paralleled by chitinase activity which showed a peak after about 72 h of cultivation where cysts accounted for 63% of cell population. thereafter, activity fell off rapidly, whereas encystment continued, reaching 80% at the end of the experiment (96 h). comparison of activity between cysts and the total cell population in 4 ... | 1992 | 1625707 |
| [antigens specific to pre-cysts and in vivo chitin synthetase activity in entamoeba invadens]. | in this paper we studied the transformation of a trophozoite into a cyst in entamoeba, using e. invadens as a model. we had the following objectives: a) identification of precyst-specific proteins (p), by a monoclonal antibody against e. invadens and heterologous polyclonal antibodies against cellular (165) fractions of mucar rouxii, which are chitin synthetase activity rich; and b) in vivo determination of the time required for the expression of activity of the chitin synthetase during encystme ... | 1990 | 1726662 |
| chitin synthase in encysting entamoeba invadens. | although the cyst wall of entamoeba invadens contains chitin, synthesis of this structural polymer during encystation has not been described before. here we report that conditions which stimulate encystation of the parasite lead to increased chitin synthase (chs) activity, measured by incorporation of [3h]glcnac ([3h]n-acetylglucosamine) from udp-glcnac. the radiolabelled product was precipitable by trichloroacetic acid or ethanol and identified as chitin because it was digested by purified chit ... | 1991 | 1764027 |
| molecular karyotype of entamoeba histolytica and entamoeba invadens. | we report the size-fractionation of entamoeba histolytica and e. invadens deoxyribonucleic acid (dna) by pulsed field gradient electrophoresis. using 3 different electrophoretic conditions, we were able to resolve 6 to 9 bands between 300 and 2000 kilobases (kb), distributed in 16-22 large and up to 31 small chromosomes for e. histolytica dna. for e. invadens, 4 to 5 bands between 300 and over 2000 kb were resolved and discriminated in 4 large and 6 small chromosomes. a ribosomal probe from tryp ... | 1990 | 2091349 |
| [trans-membrane potential in entamoeba]. | the membrane potential in entamoeba is an important driving force for the uptake of substrates. in entamoeba invadens pz a membrane potential of -36 mv was obtained when nernst equation was applied to the distribution at equilibrium of 86rb+ in the presence of valinomycin. this could explain the levels of accumulation of up to 4 times found for positively charged substrates. membrane potential was diminished by depolarizing conditions (high external k+ concentration in the presence of valinomyci ... | 1990 | 2136474 |
| antigens in electron-dense granules from entamoeba histolytica as possible markers for pathogenicity. | in vitro interaction of entamoeba histolytica with collagen induces intracellular formation and release of electron-dense granules (edg) and stimulation of collagenolytic activity. purified edg contain 1.66 u of collagenase per mg of protein. thus, edg may participate in tissue destruction during invasive amebiasis. monoclonal antibodies (mabs) l1.1 and l7.1 reacted specifically with edg in enzyme-linked immunosorbent assay (elisa) and immunofluorescence and immunoelectron microscopy. mab l7.1 i ... | 1990 | 2174899 |
| cdna sequence analysis of a 29-kda cysteine-rich surface antigen of pathogenic entamoeba histolytica. | a gamma gt11 cdna library was constructed from poly(u)-sepharose-selected entamoeba histolytica trophozoite rna in order to clone and identify surface antigens. the library was screened with rabbit polyclonal anti-e. histolytica serum. a 700-base-pair cdna insert was isolated and the nucleotide sequence was determined. the deduced amino acid sequence of the cdna revealed a cysteine-rich protein. dna hybridizations showed that the gene was specific to e. histolytica since the cdna probe reacted w ... | 1990 | 2201027 |
| purification and partial characterization of the major cysteine protease from entamoeba invadens. | the purification and partial characterization of a major protease from the parasitic protozoon of reptiles, entamoeba invadens, is described. the enzyme has a molecular mass of 28 kda, and three distinct isoelectric points at ph 4.7, 5.7 and 6.3, respectively. as an endopeptidase the enzyme digests denatured protein substrates, such as azocasein with an optimal turnover rate at ph 4.8 with a temperature optimum of 48 degrees c. the protease exhibits exopeptidase activity towards arginine contain ... | 1990 | 2275719 |
| quantitative evaluation of intracellular degradation in entamoeba invadens. | a quantitative study on digestion of erythrocytes by entamoeba invadens was attempted. trophozoites of the ip-1 strain were fed red blood cells for 30 min, and subsequently phagocytosis was stopped by means of osmotic shock; post-phagocytosis incubations for up to 15 h were made in order to evaluate intracellular digestion, after staining the red blood cells with benzidine. eighty-two per cent of trophozoites were capable of phagocytosing erythrocytes, containing an average of 5.5 erythrocytes p ... | 1990 | 2332279 |
| species-specific and cross-reactive antigens of entamoeba. | specific and cross-reactive antigens were defined in four species of entamoeba: invadens, moshkovskii, laredo and histolytica strains hm1, hm3, hm38 and hk9. among these species extensive common reactivities were observed by immunoblot. eight e. histolytica antigenic markers were revealed after blocking common specificities with antigens of other entamoeba species. a monoclonal antibody (mab) defined two protein markers of e. histolytica, mr29 and 25 kda. the four strains of e. histolytica, whic ... | 1989 | 2483955 |
| dna hybridization probe for clinical diagnosis of entamoeba histolytica. | as an alternative to microscopic identification of entamoeba histolytica parasites isolated from stool, a sensitive and species-specific dna hybridization probe was made for rapid diagnosis of e. histolytica parasites in clinical samples directly applied to nylon membranes. the dna hybridization probe was made by screening a genomic library of a virulent hm-1:imss strain of e. histolytica to detect recombinant plasmids containing highly repeated parasite dna sequences. four plasmid clones that r ... | 1989 | 2542361 |
| sialic acid is a cell surface component of entamoeba invadens trophozoites. | the surface anionic groups of entamoeba invadens were analysed by cell electrophoresis, by ultrastructural cytochemistry, and by identification of sialic acids using paper and gas-liquid chromatography. binding of colloidal iron hydroxide (cih) and of cationized ferritin (cf) particles at ph 1.8 and 7.2, respectively, was observed on the cell surface. e. invadens has a highly negative surface charge (-0.96 microns s-1 v-1 cm). treatment of the cells with trypsin and neuraminidase significantly r ... | 1989 | 2739583 |
| use of monoclonal antibodies to identify, characterize, and purify a 96,000-dalton surface antigen of pathogenic entamoeba histolytica. | we identified and partially characterized a surface antigen of entamoeba histolytica by using seven monoclonal antibodies obtained after injecting mice with a pathogenic strain of amoeba. an intrinsically radiolabeled 96,000-dalton antigen was immunoprecipitated by five of the seven monoclonal antibodies; this antigen was present in three strains of e. histolytica. the antigen was situated on the external surface of e. histolytica, as demonstrated by agglutination and immunofluorescence staining ... | 1987 | 2885384 |
| use of antibodies to characterize a 220-kilodalton surface protein from entamoeba histolytica. | antibodies were prepared against a 220-kilodalton (kda) protein partially purified by sepharose 4b chromatography of entamoeba histolytica strain hm38:imss homogenates, and the protein was found to have lectin properties. the antibodies specifically recognized this protein in trophozoite homogenates. immunologically related molecules with the same molecular weight were identified by polyclonal antibodies in strains hm1:imss, entamoeba invadens, and entamoeba histolytica laredo. six monoclonal an ... | 1987 | 2888826 |
| appearance of sialoglycoproteins in encysting cells of entamoeba histolytica. | amoeba-bacterium cultures of entamoeba histolytica transferred to a hypoosmotic medium depleted of nutrients changed morphologically and biochemically. the cells ejected grains of rice starch, rounded up, and formed a distinct cell wall that was resistant to detergent, bound the sialic acid-specific lectin from limulus polyphemus, and became fluorescent with calcofluor m2r. a subpopulation of these cells displayed more than one nucleus. all these signs are characteristic of encysting cells and w ... | 1988 | 2893775 |
| antiparasitic activity of nine pyrazole derivatives against trichomonas vaginalis, entamoeba invadens and plasmodium berghei. | nine nitropyrazole derivatives were prepared and tested against trichomonas vaginalis in vitro and in vivo, entamoeba invadens in vitro and plasmodium berghei in vivo. three of the compounds, 4-4-nitropyrazole, 1-methyl-4-nitropyrazole and 4,4'-dinitro-1,1'-methylenedipyrazole, have an activity similar to that of metronidazole (used as the reference compound) against t. vaginalis and e. invadens after 48 hours of incubation. all the compounds tested were inactive against p. berghei. | 1988 | 3074738 |
| characterization of a calcium-dependent atpase in entamoeba invadens. | a high-affinity calcium-dependent atpase (ca2+-atpase) was identified in a crude plasma membrane fraction from entamoeba invadens (ip-1 strain). the ca2+-atpase activity was solubilized from the membrane by utilizing the non-ionic detergent octylglucoside. the activity had an apparent half maximal saturation constant of 0.4 +/- 0.05 microm for free calcium. the calcium activation of atpase activity followed a cooperative mechanism (hill number of 2.3 +/- 0.13) which suggests that two interacting ... | 1985 | 3159425 |
| [changes in lysyl-trna associated with the encystment of entamoeba invadens]. | | 1986 | 3647763 |
| a stage-specific sialoglycoprotein in encysting cells of entamoeba invadens. | a novel sialoglycoprotein with an apparent molecular mass of approximately 250 kda was detected on the surface of cysts of entamoeba invadens. sialic acid was identified in this glycoprotein by gas chromatography after methanolysis; n-acetyl- and n-glycolyl neuraminic acid were identified by thin layer chromatography in hydrolysates of partially purified preparations of the 250 kda glycoprotein as well as in whole cysts. the sialoglycoprotein is stage-specific and could be detected by binding of ... | 1987 | 3696174 |
| encystation of entamoeba invadens ip-1 is induced by lowering the osmotic pressure and depletion of nutrients from the medium. | trophozoites of entamoeba invadens ip-1 can be induced to encyst in simple solutions composed of semipermeable constituents (buffer, salts, or sugars) provided that their osmotic pressure is in the range of 60-160 mosmol/kg. optimal yield of mature cysts was obtained when the osmotic pressure of the medium was 110 mosmol/kg. encystation could be obtained in the absence of serum although higher yields were obtained in its presence. no difference in the yield of mature cysts was found when either ... | 1986 | 3795143 |
| ultrastructure of entamoeba invadens cysts obtained under the effect of emetine, tinidazole and rifampin. | | 1986 | 3813763 |
| changes in cell surface proteins and glycoproteins during the encystation of entamoeba invadens. | changes in cell surface components of axenically grown trophozoites of entamoeba invadens which occur during encystation were followed. protein patterns of trophozoites, immature and mature cyst forms, were analyzed by sodium dodecyl sulphate gel electrophoresis. total protein profiles of trophozoites and cyst forms stained by coomassie blue gave similar patterns. in contrast, a number of different bands were observed in gels stained with the carbohydrate-specific schiff's reagent as well as whe ... | 1985 | 3990711 |
| zinc in entamoeba invadens. | atomic absorption spectroscopy, electron microprobe analysis, and dithizone staining of trophozoites and cysts of entamoeba invadens demonstrate that these cells have a high concentration of zinc (approximately 10(-6) microgram per cell or 1 percent of their dry weight). in the cysts of this organism, the zinc is confined to the chromatoid bodies, which previous work has shown to contain crystals of ribosomes. the chemical state and function of this zinc are unknown. | 1972 | 4113664 |
| quantitative study of dna (feulgen) in entamoeba invadens. | | 1969 | 4183123 |
| [on the relations between entamoeba histolytica, laredo strains, entamoeba invadens and entamoeba moshkovskii evaluated according to their sensitivity to anti-amebic drugs]. | | 1968 | 4313543 |
| tryptophan content and fluorescence of cysts of entamoeba invadens. | | 1974 | 4429720 |
| purification and characterization of malic enzyme of entamoeba invadens: evidence for isoenzymes. | | 1974 | 4449099 |
| in vitro effect of amoebicidal drugs against cysts of schizopyrenus russelli & entamoeba invadens. | | 1974 | 4464272 |
| [the effects of pyrrolnitrine on entamoeba invadens]. | | 1972 | 4667380 |
| the ultraviolet absorption spectra of chromatoid bodies of entamoeba invadens in situ: an optical titration. | | 1973 | 4698169 |
| the ultrastructure of cysts of entamoeba invadens. | | 1973 | 4722426 |
| antigenic relationship between the cysts and trophozoites of entamoeba invadens. | | 1967 | 4865130 |
| division of entamoeba invadens rodhain, 1934, in cultures. | | 1969 | 4895280 |
| axenic mass cultivation of entamoeba invadens and cell membrane isolation. | | 1972 | 5008843 |
| three-dimensional structure of the chromatoid body helix of entamoeba invadens. | | 1972 | 5038453 |
| evidence for a link between division and differentiation in entamoeba invadens. | | 1971 | 5091278 |
| the application of fluorescent-antibody test to cysts of entamoeba invadens. | | 1965 | 5331470 |
| three dimensional structure of the chromatoid body of entamoeba invadens. | | 1970 | 5449766 |
| [the submicroscopic structure of the chromatoid body of entamoeba invadens and entamoeba moshkovskii]. | | 1967 | 5622499 |
| the growth of an axenic strain of entamoeba invadens in different media. | | 1968 | 5740554 |
| filtration of entamoeba invadens cysts through microfabric. | | 1969 | 5821276 |
| [microelectronic research on entamoeba invadens]. | | 1965 | 5845008 |
| the fine structure of axenically-grown trophozoites of entamoeba invadens with special reference to the nucleus and helical ribonucleoprotein bodies. | | 1965 | 5860408 |
| [generalized amoebiasis without intestinal symptoms in an iguana (iguana iguana) (reptilia, iguanidae), caused by entamoeba invadens (protozoa, amoebozoa)]. | | 1966 | 6011419 |
| growth of entamoeba invadens, rodhain (1934) on pure cultures of certain bacteria. | | 1967 | 6065633 |
| [staining of cysts of entamoeba invadens, entamoeba histolytica and entamoeba coli with wheat germ agglutinin labelled with colloidal gold]. | cysts of entamoeba invadens obtained under axenic conditions were stained with wheat germ agglutinin labelled with colloidal gold. microscopic observation of encysting cultures revealed that upon staining, cysts acquired a red coloration, while trophozoites remained unstained. e. histolytica and e. coli cysts obtained from asymptomatic patients were also stained red by this technique. electronmicroscopic examination of stained cells showed a layer of colloidal gold granules attached to the surfa ... | 1980 | 6162428 |
| ribonuclease of entamoeba invadens. | two bands of rnaase activity were observed on gel electrophoresis of fractions obtained during partial purification of the rnaase of entamoeba invadens. the faster migrating band which was responsible for most of the rnaase activity was isolated by gel electrophoresis. a pi of 5.5 was determined for this rnaase activity and estimates of its molecular weight and sedimentation coefficient gave values of about 25 000 and approximately 2.8 s. it exhibited maximum activity around ph 6, and digestion ... | 1981 | 6172708 |
| location on chitin in the cyst wall of entamoeba invadens with colloidal gold tracers. | chitin was located in the cyst wall of entamoeba invadens with colloidal gold-linked wheat germ agglutinin. cysts stained differentially from trophozoites when encysting cultures were treated with the gold tracer; cysts acquired a wine-red coloration while, in general trophozoites remained unstained. observation of cells with the electron microscope revealed that the tracer particles were bound specifically to the walls of the surface of the cyst when cells were exposed in suspension, and to the ... | 1982 | 6176704 |
| [chitinolytic activity of entamoeba invadens]. | | 1982 | 6217794 |
| entamoeba histolytica and entamoeba invadens: effects of temperature and oxygen tension on growth and survival. | | 1980 | 6245905 |
| entamoeba invadens and e. histolytica: separation and purification of precysts and cysts by centrifugation on discontinuous density gradients of percoll. | the different cell forms in the life cycle of entamoeba invadens (trophozoites, precysts, and cysts) were rapidly and quantitatively separated on density step gradients of polyvinylpyrolidone-coated colloidal silica particles (percoll). with this method, the gradual process of encystation by e. invadens trophozoites could be monitored. percoll gradients were also efficient in separating trophozoites of entamoeba histolytica and bacteria. after purification on percoll, trophozoites display no evi ... | 1983 | 6303827 |
| preliminary characterization of ribosomes of entamoeba invadens. | the ribosomes of entamoeba invadens trophozoites have sedimentation coefficients of 77, 53 and 36 s. most of the ribosomal proteins are basic and their one- and two-dimensional electrophoretic patterns differ from the corresponding patterns of escherichia coli and saccharomyces cerevisiae. two dozen bands were observed in the 10 000 to 100 000 molecular weight range following sodium dodecylsulfate-gel electrophoresis of amoebal ribosomal proteins. long, thin pronase-sensitive structures were see ... | 1983 | 6348536 |
| polyamines in entamoeba invadens. | the polyamine content of entamoeba was measured by a procedure that involved benzoylation followed by high performance liquid chromatography (h.p.l.c.). a high concentration of putrescine and significant amounts of spermidine and spermine were found in actively growing trophozoites and in the cyst forms of the organism. in contrast, trophozoites in stationary phase had greatly reduced amounts of putrescine and exhibited peaks in h.p.l.c., possibly indicative of acetylated polyamines. alpha-d,l-d ... | 1984 | 6432358 |
| induction of encystation of entamoeba invadens by removal of glucose from the culture medium. | a procedure has been developed for the effective induction of axenic encystation of entamoeba invadens strain ip-1. low concentrations of glucose in diamond's axenic growth medium cause stimulation of the differentiative process. the time course of encystation depended on the density of inoculum. while a culture with an inoculum of 5 x 10(4) cells/ml required about 3 days to initiate encystment, a culture with an inoculum of 1 x 10(6) cells/ml required only 8 hr. cyst yield was optimal (70%) whe ... | 1984 | 6512629 |
| isoelectric point and molecular weight of a diaphorase of entamoeba invadens. | | 1982 | 6896214 |
| [changes in the encystment of entamoeba invadens caused by calcofluor m2r]. | | 1982 | 7181601 |
| [nuclear division and presence of microtubules in the differentiation of entamoeba invadens]. | | 1982 | 7181602 |
| a simple procedure for partial purification of an rnaase of entamoeba invadens. | the behavior of an rnaase, present in centrifugally clarified homogenates of axenic trophozoites of entamoeba invadens, on isoelectric focusing (ief) and agarose-poly(g) chromatography is described. the results led to a simple two-step procedure for partial purification of the rnaase in which fractionation of the homogenate by ief is followed by agarose-poly(g) chromatography. recovery of enzyme activity has ranged from 50 to 80% of that present in homogenates, and increases of 80- to 160-fold i ... | 1981 | 7296417 |
| identification of the structural component in the cyst wall of entamoeba invadens. | cyst walls of entamoeba invadens were isolated and purified. both whole cysts and purified walls appeared intensely fluorescent when stained with calcofluor white m2r. examination of positive replicas of purified cyst walls with the electron microscope revealed the presence of a microfibrillar structure. the main sugars detected in acid hydrolysates from the walls were hexosamines. x-ray diffraction analysis of purified cyst walls demonstrated that the crystalline polymer present was chitin. | 1980 | 7463242 |
| osmotic stress as a factor controlling encystation of entamoeba invadens. | | 1980 | 7469635 |
| [origin of sac-shaped walls in entamoeba invadens cultures during the encystment process]. | changes in the population of trophozoites, cysts and bag-shaped walls in an encysting culture of entamoeba invadens were determined. the results indicated that bag-shaped walls do not play a precursor role in the encystation of the organism. samples of cells from encysting cultures were stained in vivo with calcofluor m2r. microscopic observations indicated also that bag-shaped walls do not play a precursor role in the formation of the cyst. it was suggested that bag-shaped walls arise from an a ... | 1980 | 7469637 |
| the relationship of dna synthesis and cell cycle events to encystation by entamoeba invadens. | | 1980 | 7469646 |
| [life cycle of entamoeba invadens studied by means of spatial cinematography]. | | 1980 | 7469648 |
| elucidation of the dna synthetic cycle of entamoeba spp. using flow cytometry and mathematical modeling. | we developed a method to study the dna synthetic cycles of entamoeba histolytica and entamoeba invadens by flow cytometry (fcm) based on a preparative procedure to reduce both high levels of natural fluorescence and non-specific adsorption of fluorochromes. we modeled g1, s, and g2 phases as a series of overlapping gaussian curves. both e. histolytica and e. invadens displayed g1, s, and g2 proportions that are consistent with eukaryotic cell populations in exponential or stationary growth phase ... | 1995 | 7581336 |
| lipophosphoglycan is present in distinctly different form in different entamoeba histolytica strains and absent in entamoeba moshkovskii and entamoeba invadens. | lipophosphoglycan has recently been demonstrated on the cell surface of entamoeba histolytica strain hm-1:imss. a monoclonal antibody against this molecule had failed to react with some other strains of e. histolytica, including the strain rahman. to determine if a structurally distinct lipophosphoglycan existed in rahman, [3h]galactose-labeled glycoconjugates were electrophoresed through sodium dodecyl sulfate polyacrylamide gel electrophoresis. the electrophoretic pattern in rahman was very di ... | 1995 | 7581337 |
| intestinal inflammation associated with flagellates in snakes. | the intestines of 51 snakes with histologically diagnosed or suspected amoebiasis were reinvestigated immunohistochemically with an entamoeba invadens antibody. in 22 cases, trophozoites of entamoeba invadens stained positively in the inflamed intestinal wall, but the protozoa visible in the pathologically changed intestines of a further 20 snakes were negative. on the basis of light and electron microscopical findings, these protozoa were identified as flagellates. | 1995 | 7593763 |
| killing of entamoeba invadens using liposome-encapsulated drugs. | liposomes are used as carriers of drugs intended to manipulate macrophage functions. the normal in vivo fate of liposomes is phagocytosis, followed by phospholipase-mediated disruption of their phospholipid bilayers and intracellular release of their contents. using this method for intracellular delivery of drugs, we have developed an approach for in vivo depletion of macrophages. phagocytosis also forms a major feature of parasitic amoebae. in the present experiments, we investigated whether am ... | 1995 | 7770433 |
| identification of a developmentally regulated transcript expressed during encystation of entamoeba invadens. | differentiation of trophozoites into cysts in entamoeba species has been described morphologically and to a lesser extent biochemically, but studies of stage specific gene expression have not been reported. at present entamoeba invadens is the only species that can be induced to differentiate in axenic culture and is a useful model system for the human parasite entamoeba histolytica. using this model system, we performed cdna-mrna hybridization experiments to compare the rna populations from tro ... | 1994 | 7838173 |
| increased levels of polyadenylated histone h2b mrna accumulate during entamoeba invadens cyst formation. | we have isolated cdna clones of a member of the histone h2b protein family by differential screening of an entamoeba invadens cdna library with cdna probes from vegetatively growing or encysting parasites. the cdna clones reveal two polyadenylation sites, 26 nucleotides and 31 nucleotides downstream from the stop codon. rna species recognized by e. invadens histone h2b clones are found at increased levels during cyst formation. histone h2b rna could be detected in both the poly(a)+ and poly(a)- ... | 1994 | 7838174 |
| heterogeneity of the ribosomal dna episome in strains and species of entamoeba. | ribosomal dna sequences in several species of the genus entamoeba are highly repeated and display restriction fragment-length polymorphism (rflp), which has been used to identify species and differentiate strains. however, the continuous variability of the non-transcribed repeat sequences in the ribosomal episome hinders an accurate typification. looking for more reliable markers, we used dna probes containing conserved sequences in the ribosomal episome--coding regions for the 16s and 5.8s rrna ... | 1994 | 7934884 |
| actin mrna levels and actin synthesis during the encystation of entamoeba invadens. | parasitic amebas propagate among hosts through cysts, the resistant forms in their life cycle. in spite of their key role in infection, little is known about the encystation process and the mechanisms involved in reaching this stage. two features drastically affected by encystation are motility and cell shape, both of which are determined by the cytoskeleton, composed mainly of actin in these organisms. therefore, we studied the occurrence and relative levels of actin and actin synthesis during ... | 1994 | 8087106 |
| ornithine decarboxylase activity in entamoeba invadens. | growth of e. invadens was paralleled by a concomitant increase in ornithine decarboxylase activity which peaked after 5 days of cultivation in tyi-s-33 medium. over this period, enzyme activity increased about nine-fold with respect to that present at the start of incubation. thereafter and coinciding with the onset of the stationary growth phase, enzyme activity started to decline reaching trace levels after 8 days of cultivation. most of the enzyme remained soluble following centrifugation of ... | 1993 | 8314367 |
| entamoeba histolytica: electrophysiologic and morphologic effects of trophozoite lysates on rabbit colon. | although in acute intestinal amoebiasis the events occurring during the initial interaction of entamoeba histolytica trophozoites with the mucosa of the large intestine probably determine the invasion by the parasites, an appropriate experimental model to study them does not exist. to develop such a model we used rabbit colonic segments (0.28 cm2) mounted in ussing-type chambers. these preparations had electrophysiological properties (potential difference, short-circuit current, and electrical r ... | 1993 | 8375485 |
| entamoeba histolytica encodes a highly divergent beta-tubulin. | the microtubules of the amitochondrial parasite entamoeba histolytica are atypical in certain respects. consistent with this, we report that e. histolytica encodes the most divergent beta-tubulin identified to date, with only 54% to 58% identity to beta-tubulins from various species. a similarly divergent beta-tubulin is encoded by the related entamoeba invadens; single gene copies appear to be present in both organisms. the entamoeba sequences were compared with a database of 101 beta-tubulins, ... | 1996 | 8563707 |
| simultaneous growth and mass encystation of entamoeba invadens under axenic conditions. | encystation of entamoeba invadens ip-1 strain trophozoites was induced in low glucose medium (lg). the numbers of trophozoites, cysts and nuclei per cyst were determined; excystation of detergent-resistant axenic cysts was induced in both bi-s-33 and lg media. it was found that after 48 and 72 h of incubation in lg, cyst production was higher than trophozoites inoculated, 90 and 65% of those cysts being morphologically viable, respectively, as differentiation proceeded cysts became tri- and tetr ... | 1995 | 8580677 |
| pathogenic action of entamoeba invadens: intestinal epithelium invasion by trophozoites in vitro. | interactions between live entamoeba invadens trophozoites and guinea-pig caecal explants were studied. a high percentage of amoebae adhering to the apical surface of epithelial cells was observed 10-20 min after infection, but no histopathological changes were observed. after 30 min, mild oedema at the base of the interglandular epithelium and death of some epithelial cells were evident. the epithelial barrier was invaded by amoebae at desquamating zones and phagocytosis of epithelial cells or c ... | 1996 | 8786220 |