The Entamoeba histolytica genome: something old, something new, something borrowed and sex too?
Samuel L. Stanley, Jr
Departments of Medicine and Molecular Microbiology, Midwest Regional Center of Excellence for Biodefense and Emerging Infectious Diseases Research, Washington University School of Medicine, Saint Louis, MO 63110, USA
Entamoeba histolytica is an intestinal protozoan parasite of humans that causes amebic colitis and amebic liver abscess: diseases associated with significant levels of morbidity and mortality worldwide . The organism has a simple life cycle, existing as either the motile trophozoite or the infectious, hardy cyst form. Trophozoites of E. histolytica reside within the anaerobic confines of the human colon, lack mitochondria, derive energy from fermentation and reproduce by binary fission. E. histolytica trophozoites can be potent pathogens, possessing an armamentarium that includes a galactose–N-acetyl-galactosamine-binding lectin that mediates adherence to host cells, pore-forming proteins (amebapores) that can lyse bacteria or eukaryotic cells, cysteine proteinases that can cleave extracellular-matrix proteins and facilitate invasion into the colonic mucosa, and impressive phagocytic capabilities . During the past three decades, the tools of molecular biology have greatly increased the understanding of E. histolytica pathogenesis. The recent publication of the E. histolytica genome by Loftus et al.  provides remarkable new insights into the biology of E. histolytica, helps understanding of the requirements for intestinal parasitism and sets the stage for a new, far more detailed understanding of this important pathogen.
Source: Trends Parasitol. 2005 October; 21(10): 451–453