Electron microscopy of<i>Entamoeba histolytica</i>in culture

Lowe, Cheng Yee; Maegraith, B. G.

doi:10.1080/00034983.1970.11686693

Cited by 24 publications

(4 citation statements)

References 28 publications

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“…Previous electron microscope studies on intact E. invadens had already revealed the absence of mitochondria and the presence of nuclei, ribosomes, and a scarcely developed endoplasmic reticulum and Golgi apparatus (8,9,21,22,23,30,31,32). The electron micrograph of the plasma membrane fraction isolated in the present study shows the absence of nuclei and ribonucleoprotein and little contamination with glycogen (Fig.…”

Section: Morphology Of Plasma and Phagolysosomal Membranessupporting

confidence: 71%

Isolation and characterization of subcellular membranes of Entamoeba invadens.

Vliet¹,

Spies²,

Linnemans³

et al. 1976

The Journal of Cell Biology

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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 electron microscopy, and the contamination of each fraction was determined with marker enzymes. Mg2+-ATPase is associated with the plasma membrane. Acid phosphatase (/3-glycerophosphate) was associated mainly with phagolysosomal membranes. Plasma membranes also contained acid phosphatase activity which hydrolyzes p-nitrophenylphosphate but not fl-glycerophosphate. The localization of the two phosphatases was confirmed cytochemically.Isolated plasma membranes were contaminated with phagolysosomal membranes (15%) and with microsomes (25%). No more than 5% of the phagolysosomal membrane fraction consisted of plasma membranes. Contamination of the microsomes by plasma and phagolysosomal membranes was 10% and 7%, respectively. Plasma membranes and phagolysosomal membranes had a high ratio of cholesterol to phospholipid (0.93 and 1.05 /xmol/#mol, respectively). Microsomes were relatively poor in cholesterol (0.39 /~mol//zmol).Microsomes, plasma, and phagolysosomal membranes contained increasing amounts of sphingolipids (12%, 17%, and 28%). Phagolysosomal membranes had a high percentage of phosphatidylserine but little phosphatidylcholine. Microsomes were rich in phosphatidylcholine (45%). Differences in phospholipid composition between plasma and phagolysosomal membranes are discussed in view of the phagocytic process.Electron micrographs of Entamoeba reveal the relatively simple structure of these protozoan cells (Fig. 1). The main organelles are the phagolysosomes (31,32) which are scattered throughout the cell. A nucleus is present as well as a Golgi apparatus (9, 30) and endoplasmic reticulum (22, 23,

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Section: Morphology Of Plasma and Phagolysosomal Membranessupporting

confidence: 71%

Isolation and characterization of subcellular membranes of Entamoeba invadens.

Vliet¹,

Spies²,

Linnemans³

et al. 1976

The Journal of Cell Biology

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“…We have never encountered similar filamentous structures either in normal amoebae or in amoebae infected with polyhedral viruses derived from amoebae other than the ABRM strain (3). Likewise investigations in other laboratories (4,8,9) FIG. 5.…”

Section: Resultsmentioning

confidence: 55%

“…As may be seen in the binucleate amoeba in Fig. 1, the general architecture of both nuclei and cytoplasm appears relatively normal (4,8,9). A number of prominent vesicles are seen and the cytoplasm characteristically contains a large number of densely staining glycogen granules.…”

Section: Resultsmentioning

confidence: 84%

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Viruses of Entamoeba histolytica II. Morphogenesis of the Polyhedral Particle (ABRM ₂ →HK-9)→HB-301 and the Filamentous Agent (ABRM) ₂ →HK-9

Mattern

Diamond

Daniel

1972

J Virol

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The intracellular development of two morphologically different amoebal viruses has been studied by electron microscopy. One is a polyhedral agent which was observed as early as 24 hr after infection in the perinuclear cytoplasm. Subsequently, cell lysis occurred and particles were found in large number bound to membranes of disrupted amoebae. Other particles were found in phagocytic vacuoles suggesting a possible portal of entry into amoebae. The other virus is a filamentous particle which is first seen in small clusters in the nucleus after 24 hr of infection. The number of particles increases such that by 72 hr massive whorls of particles occupy a substantial part of the nucleus. After rupture of the nuclear membrane, clusters of filaments are widely dispersed throughout the cytoplasm. Still later, the cytoplasmic membrane disintegrates and clusters of filaments are found extracellularly, but free of cell membranes. The morphology of these agents is discussed in comparison with a variety of plant, animal, and bacterial viruses.

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