Immunobiology of Human Infection by &lt;i&gt;Entamoeba histolytica&lt;/i&gt;

Ravdin, Jonathan I.

doi:10.1159/000157148

Cited by 26 publications

(21 citation statements)

References 59 publications

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“…E. histolytica is well known for its high potential for invading and destroying human tissue, leading to diseases such as hemorrhagic colitis and extraintestinal abscesses (30). The parasite usually lives and multiplies within the human gut, which constitutes an environment of reduced oxygen pressure.…”

mentioning

confidence: 99%

The 29-Kilodalton Thiol-Dependent Peroxidase of Entamoeba histolytica Is a Factor Involved in Pathogenesis and Survival of the Parasite during Oxidative Stress

et al. 2007

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The 29-kDa surface antigen (thiol-dependent peroxidase; Eh29) of Entamoeba histolytica exhibits peroxidative and protective antioxidant activities. During tissue invasion, the trophozoites are exposed to oxidative stress and need to deal with highly toxic reactive oxygen species (ROS). In this investigation, attempts have been made to understand the role of the 29-kDa peroxidase gene in parasite survival and pathogenesis. Inhibition of eh29 gene expression by antisense RNA technology has shown approximately 55% inhibition in eh29 expression, maximum ROS accumulation, and significantly lower viability in 29-kDa downregulated trophozoites during oxidative stress. The cytopathic and cytotoxic activities were also found to decrease effectively in the 29-kDa downregulated trophozoites. Size of liver abscesses was substantially lower in hamsters inoculated with 29-kDa downregulated trophozoites compared to the normal HM1:IMSS. These findings clearly suggest that the 29-kDa protein of E. histolytica has a role in both survival of trophozoites in the presence of ROS and pathogenesis of amoebiasis.Entamoeba histolytica, the enteric protozoa, is a well-established causative agent of amoebic dysentery and liver abscesses in humans (37). E. histolytica is well known for its high potential for invading and destroying human tissue, leading to diseases such as hemorrhagic colitis and extraintestinal abscesses (30). The parasite usually lives and multiplies within the human gut, which constitutes an environment of reduced oxygen pressure. During tissue invasion, E. histolytica is exposed to elevated amounts of exogenous reactive oxygen species (ROS), such as superoxide radical anions (O 2 ⅐ Ϫ ) and hydrogen peroxide (H 2 O 2 ) (14, 26). These highly toxic molecules cause severe damage to biological macromolecules, leading to metabolic malfunctions. In addition, E. histolytica has to inactivate the ROS produced by endogenous enzymes for its survival. Several defense mechanisms exist in which a wide array of enzymatic and nonenzymatic antioxidants, including superoxide dismutase (SOD), glutathione peroxidase, catalase, and glutathione, play an active role in cell survival during oxidative stress. E. histolytica produces an iron-containing SOD that is induced by superoxide anions to produce H 2 O 2 (9). Hydroperoxides produced during oxidative stress could be detoxified by a bifunctional NADPH:flavin oxidoreductase containing NADPH-dependent disulfide reductase and a H 2 O 2 -forming NADPH oxidase activity (10, 12). Catalase and glutathione reductase systems are absent in E. histolytica, but it encodes a 29-kDa cysteine-rich antigen (thiol-dependent peroxiredoxin) located on the surface of the trophozoites (8). The 29-kDa thiol-dependent peroxiredoxin of E. histolytica (Eh29) is homologous to AhpC (alkyl hydroperoxide C-22 protein) of Salmonella enterica serovar Typhimurium and Saccharomyces cerevisiae thiol-specific antioxidant protein (17). In our previous study it was clearly demonstrated that the enzymes SOD and Eh29 increased...

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confidence: 99%

The 29-Kilodalton Thiol-Dependent Peroxidase of Entamoeba histolytica Is a Factor Involved in Pathogenesis and Survival of the Parasite during Oxidative Stress

et al. 2007

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“…Infection with pathogenic Entamoeba histolytica is the cause of invasive amoebiasis in man which may lead to severe host tissue damage, colitis, and extraintestinal abscesses (1). The protozoan parasite is characterized by its extraordinary killing efficacy, which is potentially directed against almost all eukaryotic cells, including the effector cells of the host's immune system (2).…”

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confidence: 99%

Cytolytic and antibacterial activity of synthetic peptides derived from amoebapore, the pore-forming peptide of Entamoeba histolytica.

Leippe

Andrä²,

Müller‐Eberhard³

1994

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

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The pore-forming peptide amoebapore is (6), which is an amphipathic a-helical peptide of 26 residues and represents the prototype of membrane-damaging peptides (16).It is hypothesized here that the capacity of amoebapore for membrane perturbation resides within these two amphipathic helices. To test this hypothesis we synthesized peptides representing all four helical domains, including modifications thereof, and compared their pore-forming, antibacterial, and cytolytic activities with those of naturally occurring amoebapore.

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“…A very high prevalence of the disease has been reported in tropical countries like India, Mexico, Central and South America (Kingsbury et al, 1985). In the developing world, E. histolytica causes over 450 million infections per annum and about 100,000 deaths (Ravdin, 1988). In addition, the distribution of E. histolytica has been found to be more related to inadequate sanitation and poor personal hygiene than to climatic factors (Cheesbrough, 1998).…”

Section: Amoebiasis Is a Protozoan Infection Caused Bymentioning

confidence: 99%

“…Although amoebiasis is transmitted by direct contact with dirty hands or objects or through sexual contacts, the primary mode of transmission is through faecal contamination of drinking water and foods (Ravdin, 1988;Wikepedia, 2006). E. histolytica is transmitted as a result of the ingestion of infected cysts in food or water contaminated with sewage or from hands of persons contaminated with faeces.…”

Section: Amoebiasis Is a Protozoan Infection Caused Bymentioning

confidence: 99%

Transmission of amoebiasis at some selected areas of Kano Metropolis, Kano Sate, Nigeria: the role of human faeces used a manure

Ibrahmi¹

2010

Bayero J. Pure App. Sci.

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Immunobiology of Human Infection by <i>Entamoeba histolytica</i>

Cited by 26 publications

References 59 publications

The 29-Kilodalton Thiol-Dependent Peroxidase of Entamoeba histolytica Is a Factor Involved in Pathogenesis and Survival of the Parasite during Oxidative Stress

The 29-Kilodalton Thiol-Dependent Peroxidase of Entamoeba histolytica Is a Factor Involved in Pathogenesis and Survival of the Parasite during Oxidative Stress

Cytolytic and antibacterial activity of synthetic peptides derived from amoebapore, the pore-forming peptide of Entamoeba histolytica.

Transmission of amoebiasis at some selected areas of Kano Metropolis, Kano Sate, Nigeria: the role of human faeces used a manure

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