Trophozoite

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Edward L. Jarroll - One of the best experts on this subject based on the ideXlab platform.

  • in vitro excystation of spironucleus muris
    Journal of Eukaryotic Microbiology, 1996
    Co-Authors: Břetislav Koudela, Craig D Karr, Ernest A Meyer, Barbara P Meyer, Edward L. Jarroll
    Abstract:

    In vitro excystation of Spironucleus muris cysts, purified by sequential sucrose and Percoll gradients from mouse feces, was studied. Three in vitro excystation procedures, used for Giardia, were assessed to determine the most useful method. Excystation was monitored by light microscopy and subsequently characterized by transmission and scanning electron microscopy. Spironucleus muris excysted routinely at a level greater than 90% when induced in Hanks' balanced salt solution containing sodium bicarbonate at pH 2.0 and transferred to Tyrodes' salt solution as an excystation medium. Similarly, high rates of excystation were recorded after induction of S. muris cysts in 0.1 M potassium phosphate buffer (pH 7.0) with sodium bicarbonate and excystation in trypticase-yeast extract-iron medium (TYI medium) or phosphate-buffered saline. A lower rate and percentage of excystation were observed after induction of S. muris cysts in an aqueous hydrochloric acid solution (pH 2.0) followed by excystation in TYI medium. All excystation methods produced extremely active S. muris Trophozoites with normal morphology. Nonexcysting S. muris cysts have a wall composed of an outer fibrous and an inner membranous portion. Following induction, numerous vesicles appeared in the peritrophic space. Excystation began by the cyst wall opening at one pole, and the anterior part of the Trophozoite protruding from the cyst wall. The Trophozoite emerged progressively from the cyst wall and the empty cyst wall appeared to collapse. Excysted Trophozoites exhibited normal morphological features of S. muris Trophozoites isolated from the mouse intestine.

  • in vitro excystation of spironucleus muris
    Journal of Eukaryotic Microbiology, 1996
    Co-Authors: Břetislav Koudela, Craig D Karr, Ernest A Meyer, Barbara P Meyer, Edward L. Jarroll
    Abstract:

    In vitro excystation of Spironucleus muris cysts, purified by sequential sucrose and Percoll gradients from mouse feces, was studied. Three in vitro excystation procedures, used for Giardia, were assessed to determine the most useful method. Excystation was monitored by light microscopy and subsequently characterized by transmission and scanning electron microscopy. Spironucleus muris excysted routinely at a level greater than 90% when induced in Hanks' balanced salt solution containing sodium bicarbonate at pH 2.0 and transferred to Tyrodes' salt solution as an excystation medium. Similarly, high rates of excystation were recorded after induction of S. muris cysts in 0.1 M potassium phosphate buffer (pH 7.0) with sodium bicarbonate and excystation in trypticase-yeast extract-iron medium (TYI medium) or phosphate-buffered saline. A lower rate and percentage of excystation were observed after induction of S. muris cysts in an aqueous hydrochloric acid solution (pH 2.0) followed by excystation in TYI medium. All excystation methods produced extremely active S. muris Trophozoites with normal morphology. Nonexcysting S. muris cysts have a wall composed of an outer fibrous and an inner membranous portion. Following induction, numerous vesicles appeared in the peritrophic space. Excystation began by the cyst wall opening at one pole, and the anterior part of the Trophozoite protruding from the cyst wall. The Trophozoite emerged progressively from the cyst wall and the empty cyst wall appeared to collapse. Excysted Trophozoites exhibited normal morphological features of S. muris Trophozoites isolated from the mouse intestine.

  • Oxygen Uptake In Cysts and Trophozoites of Giardia Lamblia
    Journal of Eukaryotic Microbiology, 1993
    Co-Authors: Timothy A. Paget, Paul A. Manning, Edward L. Jarroll
    Abstract:

    . Oxygen uptake in cysts and Trophozoites of the parasitic protozoan Giardia lamblia was examined. Both showed oxygen uptake activity, but that of cysts was only 10% to 20% that of Trophozoites. Oxygen dependence of oxygen uptake in cysts and Trophozoites showed oxygen maxima above which oxygen uptake decreased. the oxygen concentration at which the oxygen uptake rate was greatest was higher for Trophozoites than for cysts. the effect of various inhibitors on cyst and trophozoithe oxygen uptake suggested that flavoproteins and quinones play some role in oxygen uptake. the substrate specificities and the effect of inhibitors on G. lamblia Trophozoites were similar to those observed for G. muris. Metronidazole, the drug most commonly used in treatment of giardiasis, inhibited oxygen uptake and motility in Trophozoites; however, it had no obvious effect on either oxygen uptake or excystation in cysts. Menadione, a redox cycling naphthaquinone, first stimulated, then completely inhibited, oxygen uptake in cysts and Trophozoites; a complete loss of cyst viability and Trophozoite motility was also observed. the effect of menadione on G. Iamblia may indicate that redox cycling compounds have potential as chemotherapeutic agents for the treatment of giardiasis.

Břetislav Koudela - One of the best experts on this subject based on the ideXlab platform.

  • eugregarine Trophozoite detachment from the host epithelium via epimerite retraction fiction or fact
    International Journal for Parasitology, 2009
    Co-Authors: Andrea Bardůnek Valigurova, Břetislav Koudela, Veronika Michalkova
    Abstract:

    Eugregarines represent a diverse group of Apicomplexa parasitising numerous invertebrates. Their sporozoites generally develop into epicellular Trophozoites attached to the host epithelium by a specialised attachment organelle known as an epimerite. They are considered peculiar protists due to their unique cell architecture and dimensions as well as their attachment strategy which is similar to that of cryptosporidia. Using electron and fluorescence microscopy, the fine structure of the epimerite with associated structures and the mechanism of Trophozoite detachment from the host epithelium were studied in Gregarina polymorpha parasitising the intestine of Tenebrio molitor larvae. The epimerite appears to be a very dynamic structure whose shape dramatically changes depending on whether or not it is embedded into the host epithelium. The Trophozoite's most fragile zone is the area below the membrane fusion site at the epimerite base. The epimerite plasma membrane forms basal radial ribs which are involved in increasing its surface and strengthening the epimerite-host cell junction. FITC-phalloidin labelling demonstrated the presence of filamentous actin in Trophozoites along with its accumulation at the epimerite base and in the apical end of the protomerite, as well as a patch accumulation of filamentous actin in the protomerite of maturing and mature Trophozoites. Indirect immunofluorescence revealed the presence of myosin in the cortical zone of the epimerite and in the membrane fusion site area. The data obtained strongly suggest that these structures could facilitate the detachment of a mature Trophozoite from the host epithelium. Supported by data presented herein and our previous observations, we propose a new hypothesis on the mechanism of Trophozoite detachment from the host epithelium based on epimerite retraction into the protomerite. This is contrary to the commonly accepted hypothesis describing gradual epimerite constriction and subsequent separation facilitated by contractility of the membrane fusion site (osmiophilic ring).

  • in vitro excystation of spironucleus muris
    Journal of Eukaryotic Microbiology, 1996
    Co-Authors: Břetislav Koudela, Craig D Karr, Ernest A Meyer, Barbara P Meyer, Edward L. Jarroll
    Abstract:

    In vitro excystation of Spironucleus muris cysts, purified by sequential sucrose and Percoll gradients from mouse feces, was studied. Three in vitro excystation procedures, used for Giardia, were assessed to determine the most useful method. Excystation was monitored by light microscopy and subsequently characterized by transmission and scanning electron microscopy. Spironucleus muris excysted routinely at a level greater than 90% when induced in Hanks' balanced salt solution containing sodium bicarbonate at pH 2.0 and transferred to Tyrodes' salt solution as an excystation medium. Similarly, high rates of excystation were recorded after induction of S. muris cysts in 0.1 M potassium phosphate buffer (pH 7.0) with sodium bicarbonate and excystation in trypticase-yeast extract-iron medium (TYI medium) or phosphate-buffered saline. A lower rate and percentage of excystation were observed after induction of S. muris cysts in an aqueous hydrochloric acid solution (pH 2.0) followed by excystation in TYI medium. All excystation methods produced extremely active S. muris Trophozoites with normal morphology. Nonexcysting S. muris cysts have a wall composed of an outer fibrous and an inner membranous portion. Following induction, numerous vesicles appeared in the peritrophic space. Excystation began by the cyst wall opening at one pole, and the anterior part of the Trophozoite protruding from the cyst wall. The Trophozoite emerged progressively from the cyst wall and the empty cyst wall appeared to collapse. Excysted Trophozoites exhibited normal morphological features of S. muris Trophozoites isolated from the mouse intestine.

  • in vitro excystation of spironucleus muris
    Journal of Eukaryotic Microbiology, 1996
    Co-Authors: Břetislav Koudela, Craig D Karr, Ernest A Meyer, Barbara P Meyer, Edward L. Jarroll
    Abstract:

    In vitro excystation of Spironucleus muris cysts, purified by sequential sucrose and Percoll gradients from mouse feces, was studied. Three in vitro excystation procedures, used for Giardia, were assessed to determine the most useful method. Excystation was monitored by light microscopy and subsequently characterized by transmission and scanning electron microscopy. Spironucleus muris excysted routinely at a level greater than 90% when induced in Hanks' balanced salt solution containing sodium bicarbonate at pH 2.0 and transferred to Tyrodes' salt solution as an excystation medium. Similarly, high rates of excystation were recorded after induction of S. muris cysts in 0.1 M potassium phosphate buffer (pH 7.0) with sodium bicarbonate and excystation in trypticase-yeast extract-iron medium (TYI medium) or phosphate-buffered saline. A lower rate and percentage of excystation were observed after induction of S. muris cysts in an aqueous hydrochloric acid solution (pH 2.0) followed by excystation in TYI medium. All excystation methods produced extremely active S. muris Trophozoites with normal morphology. Nonexcysting S. muris cysts have a wall composed of an outer fibrous and an inner membranous portion. Following induction, numerous vesicles appeared in the peritrophic space. Excystation began by the cyst wall opening at one pole, and the anterior part of the Trophozoite protruding from the cyst wall. The Trophozoite emerged progressively from the cyst wall and the empty cyst wall appeared to collapse. Excysted Trophozoites exhibited normal morphological features of S. muris Trophozoites isolated from the mouse intestine.

Craig D Karr - One of the best experts on this subject based on the ideXlab platform.

  • in vitro excystation of spironucleus muris
    Journal of Eukaryotic Microbiology, 1996
    Co-Authors: Břetislav Koudela, Craig D Karr, Ernest A Meyer, Barbara P Meyer, Edward L. Jarroll
    Abstract:

    In vitro excystation of Spironucleus muris cysts, purified by sequential sucrose and Percoll gradients from mouse feces, was studied. Three in vitro excystation procedures, used for Giardia, were assessed to determine the most useful method. Excystation was monitored by light microscopy and subsequently characterized by transmission and scanning electron microscopy. Spironucleus muris excysted routinely at a level greater than 90% when induced in Hanks' balanced salt solution containing sodium bicarbonate at pH 2.0 and transferred to Tyrodes' salt solution as an excystation medium. Similarly, high rates of excystation were recorded after induction of S. muris cysts in 0.1 M potassium phosphate buffer (pH 7.0) with sodium bicarbonate and excystation in trypticase-yeast extract-iron medium (TYI medium) or phosphate-buffered saline. A lower rate and percentage of excystation were observed after induction of S. muris cysts in an aqueous hydrochloric acid solution (pH 2.0) followed by excystation in TYI medium. All excystation methods produced extremely active S. muris Trophozoites with normal morphology. Nonexcysting S. muris cysts have a wall composed of an outer fibrous and an inner membranous portion. Following induction, numerous vesicles appeared in the peritrophic space. Excystation began by the cyst wall opening at one pole, and the anterior part of the Trophozoite protruding from the cyst wall. The Trophozoite emerged progressively from the cyst wall and the empty cyst wall appeared to collapse. Excysted Trophozoites exhibited normal morphological features of S. muris Trophozoites isolated from the mouse intestine.

  • in vitro excystation of spironucleus muris
    Journal of Eukaryotic Microbiology, 1996
    Co-Authors: Břetislav Koudela, Craig D Karr, Ernest A Meyer, Barbara P Meyer, Edward L. Jarroll
    Abstract:

    In vitro excystation of Spironucleus muris cysts, purified by sequential sucrose and Percoll gradients from mouse feces, was studied. Three in vitro excystation procedures, used for Giardia, were assessed to determine the most useful method. Excystation was monitored by light microscopy and subsequently characterized by transmission and scanning electron microscopy. Spironucleus muris excysted routinely at a level greater than 90% when induced in Hanks' balanced salt solution containing sodium bicarbonate at pH 2.0 and transferred to Tyrodes' salt solution as an excystation medium. Similarly, high rates of excystation were recorded after induction of S. muris cysts in 0.1 M potassium phosphate buffer (pH 7.0) with sodium bicarbonate and excystation in trypticase-yeast extract-iron medium (TYI medium) or phosphate-buffered saline. A lower rate and percentage of excystation were observed after induction of S. muris cysts in an aqueous hydrochloric acid solution (pH 2.0) followed by excystation in TYI medium. All excystation methods produced extremely active S. muris Trophozoites with normal morphology. Nonexcysting S. muris cysts have a wall composed of an outer fibrous and an inner membranous portion. Following induction, numerous vesicles appeared in the peritrophic space. Excystation began by the cyst wall opening at one pole, and the anterior part of the Trophozoite protruding from the cyst wall. The Trophozoite emerged progressively from the cyst wall and the empty cyst wall appeared to collapse. Excysted Trophozoites exhibited normal morphological features of S. muris Trophozoites isolated from the mouse intestine.

Ernest A Meyer - One of the best experts on this subject based on the ideXlab platform.

  • in vitro excystation of spironucleus muris
    Journal of Eukaryotic Microbiology, 1996
    Co-Authors: Břetislav Koudela, Craig D Karr, Ernest A Meyer, Barbara P Meyer, Edward L. Jarroll
    Abstract:

    In vitro excystation of Spironucleus muris cysts, purified by sequential sucrose and Percoll gradients from mouse feces, was studied. Three in vitro excystation procedures, used for Giardia, were assessed to determine the most useful method. Excystation was monitored by light microscopy and subsequently characterized by transmission and scanning electron microscopy. Spironucleus muris excysted routinely at a level greater than 90% when induced in Hanks' balanced salt solution containing sodium bicarbonate at pH 2.0 and transferred to Tyrodes' salt solution as an excystation medium. Similarly, high rates of excystation were recorded after induction of S. muris cysts in 0.1 M potassium phosphate buffer (pH 7.0) with sodium bicarbonate and excystation in trypticase-yeast extract-iron medium (TYI medium) or phosphate-buffered saline. A lower rate and percentage of excystation were observed after induction of S. muris cysts in an aqueous hydrochloric acid solution (pH 2.0) followed by excystation in TYI medium. All excystation methods produced extremely active S. muris Trophozoites with normal morphology. Nonexcysting S. muris cysts have a wall composed of an outer fibrous and an inner membranous portion. Following induction, numerous vesicles appeared in the peritrophic space. Excystation began by the cyst wall opening at one pole, and the anterior part of the Trophozoite protruding from the cyst wall. The Trophozoite emerged progressively from the cyst wall and the empty cyst wall appeared to collapse. Excysted Trophozoites exhibited normal morphological features of S. muris Trophozoites isolated from the mouse intestine.

  • in vitro excystation of spironucleus muris
    Journal of Eukaryotic Microbiology, 1996
    Co-Authors: Břetislav Koudela, Craig D Karr, Ernest A Meyer, Barbara P Meyer, Edward L. Jarroll
    Abstract:

    In vitro excystation of Spironucleus muris cysts, purified by sequential sucrose and Percoll gradients from mouse feces, was studied. Three in vitro excystation procedures, used for Giardia, were assessed to determine the most useful method. Excystation was monitored by light microscopy and subsequently characterized by transmission and scanning electron microscopy. Spironucleus muris excysted routinely at a level greater than 90% when induced in Hanks' balanced salt solution containing sodium bicarbonate at pH 2.0 and transferred to Tyrodes' salt solution as an excystation medium. Similarly, high rates of excystation were recorded after induction of S. muris cysts in 0.1 M potassium phosphate buffer (pH 7.0) with sodium bicarbonate and excystation in trypticase-yeast extract-iron medium (TYI medium) or phosphate-buffered saline. A lower rate and percentage of excystation were observed after induction of S. muris cysts in an aqueous hydrochloric acid solution (pH 2.0) followed by excystation in TYI medium. All excystation methods produced extremely active S. muris Trophozoites with normal morphology. Nonexcysting S. muris cysts have a wall composed of an outer fibrous and an inner membranous portion. Following induction, numerous vesicles appeared in the peritrophic space. Excystation began by the cyst wall opening at one pole, and the anterior part of the Trophozoite protruding from the cyst wall. The Trophozoite emerged progressively from the cyst wall and the empty cyst wall appeared to collapse. Excysted Trophozoites exhibited normal morphological features of S. muris Trophozoites isolated from the mouse intestine.

Barbara P Meyer - One of the best experts on this subject based on the ideXlab platform.

  • in vitro excystation of spironucleus muris
    Journal of Eukaryotic Microbiology, 1996
    Co-Authors: Břetislav Koudela, Craig D Karr, Ernest A Meyer, Barbara P Meyer, Edward L. Jarroll
    Abstract:

    In vitro excystation of Spironucleus muris cysts, purified by sequential sucrose and Percoll gradients from mouse feces, was studied. Three in vitro excystation procedures, used for Giardia, were assessed to determine the most useful method. Excystation was monitored by light microscopy and subsequently characterized by transmission and scanning electron microscopy. Spironucleus muris excysted routinely at a level greater than 90% when induced in Hanks' balanced salt solution containing sodium bicarbonate at pH 2.0 and transferred to Tyrodes' salt solution as an excystation medium. Similarly, high rates of excystation were recorded after induction of S. muris cysts in 0.1 M potassium phosphate buffer (pH 7.0) with sodium bicarbonate and excystation in trypticase-yeast extract-iron medium (TYI medium) or phosphate-buffered saline. A lower rate and percentage of excystation were observed after induction of S. muris cysts in an aqueous hydrochloric acid solution (pH 2.0) followed by excystation in TYI medium. All excystation methods produced extremely active S. muris Trophozoites with normal morphology. Nonexcysting S. muris cysts have a wall composed of an outer fibrous and an inner membranous portion. Following induction, numerous vesicles appeared in the peritrophic space. Excystation began by the cyst wall opening at one pole, and the anterior part of the Trophozoite protruding from the cyst wall. The Trophozoite emerged progressively from the cyst wall and the empty cyst wall appeared to collapse. Excysted Trophozoites exhibited normal morphological features of S. muris Trophozoites isolated from the mouse intestine.

  • in vitro excystation of spironucleus muris
    Journal of Eukaryotic Microbiology, 1996
    Co-Authors: Břetislav Koudela, Craig D Karr, Ernest A Meyer, Barbara P Meyer, Edward L. Jarroll
    Abstract:

    In vitro excystation of Spironucleus muris cysts, purified by sequential sucrose and Percoll gradients from mouse feces, was studied. Three in vitro excystation procedures, used for Giardia, were assessed to determine the most useful method. Excystation was monitored by light microscopy and subsequently characterized by transmission and scanning electron microscopy. Spironucleus muris excysted routinely at a level greater than 90% when induced in Hanks' balanced salt solution containing sodium bicarbonate at pH 2.0 and transferred to Tyrodes' salt solution as an excystation medium. Similarly, high rates of excystation were recorded after induction of S. muris cysts in 0.1 M potassium phosphate buffer (pH 7.0) with sodium bicarbonate and excystation in trypticase-yeast extract-iron medium (TYI medium) or phosphate-buffered saline. A lower rate and percentage of excystation were observed after induction of S. muris cysts in an aqueous hydrochloric acid solution (pH 2.0) followed by excystation in TYI medium. All excystation methods produced extremely active S. muris Trophozoites with normal morphology. Nonexcysting S. muris cysts have a wall composed of an outer fibrous and an inner membranous portion. Following induction, numerous vesicles appeared in the peritrophic space. Excystation began by the cyst wall opening at one pole, and the anterior part of the Trophozoite protruding from the cyst wall. The Trophozoite emerged progressively from the cyst wall and the empty cyst wall appeared to collapse. Excysted Trophozoites exhibited normal morphological features of S. muris Trophozoites isolated from the mouse intestine.