Molecular characterization of an exceptionally acidic lysozyme‐like protein from the protozoon <i>Entamoeba histolytica</i>

Nickel, Rosa; Jacobs, Thomas; Leippe, Matthias

doi:10.1016/s0014-5793(98)01220-4

Cited by 20 publications

(12 citation statements)

References 24 publications

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“…These include the genes encoding sphingomyelinase C (29.m00231), a cytolytic factor involved in hemolysis in Listeria (25), Staphylococcus (39), and other pathogenic species, and a putative lysozyme (6.m00454) which has been shown to be involved in cell lysis in many systems, including Entamoeba (41).…”

Section: Discussionmentioning

confidence: 99%

Identification of Differentially Expressed Genes in Virulent and NonvirulentEntamoebaSpecies: Potential Implications for Amebic Pathogenesis

2006

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Entamoeba histolytica is a protozoan parasite that causes colitis and liver abscesses. Several Entamoeba species and strains with differing levels of virulence have been identified. E. histolytica HM-1:IMSS is a virulent strain, E. histolytica Rahman is a nonvirulent strain, and Entamoeba dispar is a nonvirulent species. We used an E. histolytica DNA microarray consisting of 2,110 genes to assess the transcriptional differences between these species/strains with the goal of identifying genes whose expression correlated with a virulence phenotype. We found 415 genes expressed at lower levels in E. dispar and 32 genes with lower expression in E. histolytica Rahman than in E. histolytica HM-1:IMSS. Overall, 29 genes had decreased expression in both the nonvirulent species/strains than the virulent E. histolytica HM-1:IMSS. Interestingly, a number of genes with potential roles in stress response and virulence had decreased expression in either one or both nonvirulent Entamoeba species/strains. These included genes encoding Fe hydrogenase (9.m00419), peroxiredoxin (176.m00112), type A flavoprotein (6.m00467), lysozyme (6.m00454), sphingomyelinase C (29.m00231), and a hypothetical protein with homology to both a Plasmodium sporozoite threonine-asparagine-rich protein (STARP) and a streptococcal hemagglutinin (238.m00054). The function of these genes in Entamoeba and their specific roles in parasite virulence need to be determined. We also found that a number of the non-long-terminal-repeat retrotransposons (EhLINEs and EhSINEs), which have been shown to modulate gene expression and genomic evolution, had lower expression in the nonvirulent species/strains than in E. histolytica HM-1:IMSS. Our results, identifying expression profiles and patterns indicative of a virulence phenotype, may be useful in characterizing the transcriptional framework of virulence.

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Section: Discussionmentioning

confidence: 99%

Identification of Differentially Expressed Genes in Virulent and NonvirulentEntamoebaSpecies: Potential Implications for Amebic Pathogenesis

2006

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“…Among several hydrolases and membranepermeabilizing factors involved in the degradation of internalized host cells and microorganisms, e.g. CP (26), amoebapores (27), lysozyme (54), and phospholipases (55), we tested whether amoebapore A and CP2 were transported to phagosomes via PPV. Immunostaining of amoebapore and CP2 using specific antisera showed similar patterns to those obtained with LysoTracker in the absence of red blood cells (Fig.…”

Section: Ehrab5 Is Not Associated With Endosomes or Lysosomes But Exhmentioning

confidence: 99%

Rab5-associated Vacuoles Play a Unique Role in Phagocytosis of the Enteric Protozoan Parasite Entamoeba histolytica

Saito‐Nakano

Yasuda

Nakada‐Tsukui

et al. 2004

Journal of Biological Chemistry

Self Cite

128

174

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In mammals, Rab5 and Rab7 play a specific and coordinated role in a sequential process during phagosome maturation. Here, we report that Rab5 and Rab7 in the enteric protozoan parasite Entamoeba histolytica, EhRab5 and EhRab7A, are involved in steps that are distinct from those known for mammals. EhRab5 and EhRab7A were localized to independent small vesicular structures at steady state. Priming with red blood cells induced the formation of large vacuoles associated with both EhRab5 and EhRab7A ("prephagosomal vacuoles (PPV)") in the amoeba within an incubation period of 5-10 min. PPV emerged de novo physically and distinct from phagosomes. PPV were gradually acidified and matured by fusion with lysosomes containing a digestive hydrolase, cysteine proteinase, and a membrane-permeabilizing peptide amoebapore. After EhRab5 dissociated from PPV, 5-10 min later, the EhRab7A-PPV fused with phagosomes, and EhRab7A finally dissociated from the phagosomes. Immunoelectron and light micrographs showed that PPV contained small vesicle-like structures containing fluid-phase markers and amoebapores, which were not evenly distributed within PPV, suggesting that the mechanism was similar to multivesicular body formation in PPV generation. In contrast to Rab5 from other organisms, EhRab5 was involved exclusively in phagocytosis, but not in endocytosis. Overexpression of wild-type EhRab5 enhanced phagocytosis and the transport of amoebapore to phagosomes. Conversely, expression of an EhRab5Q67L GTP form mutant impaired the formation of PPV and phagocytosis. Altogether, we propose that the amoebic Rab5 plays an important role in the formation of unique vacuoles, which is essential for engulfment of erythrocytes and important for packaging of lysosomal hydrolases, prior to the targeting to phagosomes.

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“…The anaerobic environment found in the colon may favor oxygen-independent mechanisms as a means of destroying bacteria, rather than using oxygen metabolites and nitric oxide. Amebapores and other proteins, like the recently characterized ameba lysozyme that colocalizes to the same cytoplasmic granules of amebapores (61,105), could synergistically enhance the antibacterial activity.…”

Section: Early Invasive Lesions With Superficial Ulcerationmentioning

confidence: 99%

Pathogenesis of Intestinal Amebiasis: From Molecules to Disease

Espinosa‐Cantellano¹,

Martı́nez-Palomo²

2000

Clinical Microbiology Reviews

191

115

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Molecular characterization of an exceptionally acidic lysozyme‐like protein from the protozoon Entamoeba histolytica

Cited by 20 publications

References 24 publications

Identification of Differentially Expressed Genes in Virulent and NonvirulentEntamoebaSpecies: Potential Implications for Amebic Pathogenesis

Identification of Differentially Expressed Genes in Virulent and NonvirulentEntamoebaSpecies: Potential Implications for Amebic Pathogenesis

Rab5-associated Vacuoles Play a Unique Role in Phagocytosis of the Enteric Protozoan Parasite Entamoeba histolytica

Pathogenesis of Intestinal Amebiasis: From Molecules to Disease

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