Molecular Biology of DNA inAcanthamoeba, Amoeba, Entamoeba, and Naegleria

doi:10.1016/S0074-7696(08)61430-8

International Review of Cytology

Volume 99, 1986, Pages 311-341

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This chapter discusses the molecular biology of DNA in acanthameba, ameba, entameba, and naegleria. The chapter reviews a reasonably current review about gene structure and the overall organization of the DNA and its metabolism. The four genera of amebas that have been studied most extensively are described. The genus ameba includes large free-living organisms. The cell cycle is simple; replication is by binary fission and differentiation is unknown. These amebas are large enough to manipulate by various surgical procedures, and this attribute has been exploited extensively. Cultures typically are grown using the ciliated protozoan tetrahymena as the major food organism. The genus acanthameba includes small amebas that are ordinarily free-living, but can be opportunistic pathogens of animals and humans. Such organisms are considered amphizoic. In a few cases, infection has been lethal, but these organisms are ubiquitous in nature and most humans appear to have good resistance to infections. The taxonomy of acanthameba is confusing, and it is unclear whether pathogenicity is restricted to certain species or whether all strains are capable of it. acanthameba replicate by binary fission. They differentiate into dormant cysts (that is, they encyst) during adverse environmental conditions. The genus naegleria includes small amebas that can differentiate either into a cyst or a flagellated stage. In naegleria, it is clear that certain species are pathogenic and that other species are not. The pathogenic Naegleria fowleri is highly virulent and fatal to humans. The genus entameba is distinct from the rest because it includes anaerobes and parasites. The life cycle includes a phase of replication by binary fission and encystment, which occurs in response to environmental factors. Nuclear division can continue in the cyst in the absence of cytoplasmic division. Species are typically identified according to their hosts. Entameba histolytica, the human parasite, and Entameba invadens, a parasite of reptiles, are the two most commonly studied species. Both can be grown axenically under anaerobic conditions. Entameba moshkovskii is interesting because it appears to be free-living.

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Molecular Biology of DNA inAcanthamoeba, Amoeba, Entamoeba, and Naegleria

Publisher Summary

Mol. Biochem. Parasitol.

Biochim. Biophys. Acta

Exp. Cell Res.

FEMS Microsc. Lett.

Adv. Virus Res.

J. Biol. Chem.

Exp. Cell Res.

Dev. Biol.

Exp. Cell Res.

Exp. Parasitol.

Exp. Cell Res.

Biochim. Biophys. Acta

Exp. Cell Res.

J. Mol. Biol.

Exp. Cell Res.

Experientia

Cytobios

Ann. Soc. Belge Med. Trop.

J. Protozool.

J. Protozool.

Nature (London)

Ann. Trop. Med. Parasitol.

Eur. J. Biochem.

J. Cell. Physiol.

J. Cell Biol.

Int. Rev. Cytol.

J. Protozool.

J. Protozool.

Nucleic Acids Res.

J. Gen. Microbiol.

J. Gen. Microbiol.

J. Protozool.

J. Histochem. Cytochem.

Biochemistry

Acta Microbiol. Pol.

Acta Microbiol. Pol.

Proc. Natl. Acad. Sci. U.S.A.

Biochem. Syst. Ecol.

Comp. Biochem. Physiol.

Annu. Rev. Microbiol.

Proc. Natl. Acad. Sci. U.S.A.

J. Parasitol.