Electron microscopy of an axenic strain of<i>Entamoeba histolytica</i>

Lowe, Cheng Yee; Maegraith, B. G.

doi:10.1080/00034983.1970.11686694

Cited by 30 publications

(14 citation statements)

References 5 publications

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“…This conclusion is in conflict with earlier reports that E. histolytica lacks a continuous ER compartment, which were based on work conducted with fixed amebic trophozoites (6,8,11,13,16). The inability to detect a continuous ER compartment in prior studies presumably was an artifact of fixation.…”

contrasting

confidence: 55%

“…Beyond its medical importance, E. histolytica has several unusual features that are of interest to evolutionary biologists. It is a structurally simple eukaryote, lacking mitochondria and peroxisomes and having no recognizable Golgi complex or rough endoplasmic reticulum (ER) (6,11,16). Some have hypothesized that E. histolytica diverged from other eukaryotic lineages prior to the development of these structures (2).…”

mentioning

confidence: 99%

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Evidence of a Continuous Endoplasmic Reticulum in the Protozoan Parasite Entamoeba histolytica

Teixeira

Huston

2008

Eukaryot Cell

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contrasting

confidence: 55%

mentioning

confidence: 99%

Evidence of a Continuous Endoplasmic Reticulum in the Protozoan Parasite Entamoeba histolytica

Teixeira

Huston

2008

Eukaryot Cell

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“…histolytica displays particular biological characteristics, for example, the absence of mitochondria and peroxisomes, a non-recognizable Golgi apparatus, and lack of structural ER. These features have been the source of different hypotheses concerning the lineage of E. histolytica to the eukaryotes organisms (El-Hashimi and Pittman 1970;Lowe and Maegraith 1970;Rosenbaum and Wittner 1970;Bakker-Grunwald, and Wostmann 1993;Clark and Roger 1995). Previous data on transmission electron microscopy and confocal microscopy of pre-fixed E. histolytica trophozoites suggest that the endoplasmic reticulum is a network of vesicles of heterogeneous sizes (Mazzuco et al 1997;Ghosh et al 1999).…”

Section: Discussionmentioning

confidence: 93%

Entamoeba histolytica calreticulin: an endoplasmic reticulum protein expressed by trophozoites into experimentally induced amoebic liver abscesses

et al. 2010

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Entamoeba histolytica calreticulin (EhCRT) is remarkably immunogenic in humans (90-100% of invasive amoebiasis patients). Nevertheless, the study of calreticulin in this protozoan is still in its early stages. The exact location, biological functions, and its role in pathogenesis are yet to be fully understood. The aim of the present work is to determine the location of EhCRT in virulent trophozoites in vivo and the expression of the Ehcrt gene during the development of experimentally induced amoebic liver abscesses (ALA) in hamsters. Antibodies against recombinant EhCRT were used for the immunolocalization of EhCRT in trophozoites through confocal microscopy; immunohistochemical assays were also performed on tissue sections of ALAs at different times after intrahepatic inoculation. The expression of the Ehcrt gene during the development of ALA was estimated through both in situ RT-PCR and real-time RT-PCR. Confocal assays of virulent trophozoites showed a distribution of EhCRT in the cytoplasmic vesicles of different sizes. Apparently, EhCRT is not exported into the hepatic tissue. Real-time RT-PCR demonstrated an over-expression of the Ehcrt gene at 30 min after trophozoite inoculation, reaching a peak at 1-2 h; thereafter, the expression fell sharply to its original levels. These results demonstrate for the first time in an in vivo model of ALA, the expression of Ehcrt gene in E. histolytica trophozoites and add evidence that support CRT as a resident protein of the ER in E. histolytica species. The in vivo experiments suggest that CRT may play an important role during the early stages of the host-parasite relationship, when the parasite is adapting to a new environment, although the protein seems to be constitutively synthesized. Moreover, trophozoites apparently do not export EhCRT into the hepatic tissue in ALA.

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“…In higher eukaryotes, the Golgi apparatus and endoplasmic reticulum are easily recognizable; however, E. histolytica has an atypical Golgi apparatus and endoplasmic reticulum that differ from higher eukaryotes. This protozoan has no recognizable Golgi complex or endoplasmic reticulum (el‐Hashimi & Pittman, ; Lowe & Maegraith, ; Rosenbaum & Wittner, ); however, there is evidence that E. histolytica has a continuous ER network and Golgi apparatus such as that of other eukaryotic cells (Bredeston, Caffaro, Samuelson, & Hirschberg, ; Chávez‐Munguía, Espinosa‐Cantellano, Castañón, & Martínez‐Palomo, ; Teixeira & Huston, ). Additionally, the presence of other organelles, that are not present in other eukaryotes, such as giant endocytic vesicles (Verma, Saito‐Nakano, Nozaki, & Datta, ) and prephagosomal vacuoles (Saito‐Nakano et al, ), have been described.…”

Section: Discussionmentioning

confidence: 99%

EhRab21 mobilization during erythrophagocytosis in Entamoeba histolytica

Constantino‐Jonapa

Hernández‐Ramírez

Osorio-Trujillo

et al. 2018

Microscopy Res & Technique

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Rab proteins are present in all eukaryotic lineages and regulate vesicular trafficking. Entamoeba histolytica has approximately 100 genes encoding Rab proteins, among which 16 have homology with human Rab proteins. Human Rab21 participates in integrin recycling, and thus amoebic Rab21 was believed to regulate the mobilization of Ehβ1FNR (integrin‐like fibronectin receptor related with human integrin β1). We analyzed the distribution of EhRab21 using a polyclonal antibody produced with a specific peptide against the amoebic Rab protein, using confocal microscopy and specific probes for different organelles. EhRab21 was not associated with Ehβ1FNR in fibronectin‐stimulated trophozoites. However, EhRab21 was relocalized to lysosomes in erythrophagocytosis assays and was also found in Golgi‐positive structures and the nuclear periphery. These results suggest that EhRab21, unlike its human homologue, is not present in the recycling pathway. However, according to the results, EhRab21 may regulate the trafficking between lysosomes and the Golgi apparatus.

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Electron microscopy of an axenic strain ofEntamoeba histolytica

Cited by 30 publications

References 5 publications

Evidence of a Continuous Endoplasmic Reticulum in the Protozoan Parasite Entamoeba histolytica

Evidence of a Continuous Endoplasmic Reticulum in the Protozoan Parasite Entamoeba histolytica

Entamoeba histolytica calreticulin: an endoplasmic reticulum protein expressed by trophozoites into experimentally induced amoebic liver abscesses

EhRab21 mobilization during erythrophagocytosis in Entamoeba histolytica

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