• 제목/요약/키워드: (co)amoeba

검색결과 7건 처리시간 0.019초

Acmthmoeba culbertsoni 감염에 대한 silica 투여의 영향 - 대식세포의 역할을 중심으로 - (The effect of silica on the development of experimental Acanthamoeba meningoencephalitis with reference to the macrophage role in mice)

  • 이홍수;신호준
    • Parasites, Hosts and Diseases
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    • 제32권4호
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    • pp.259-266
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    • 1994
  • CSH/HeJ 마우스에 Acanaamoeba culbertsoni영양형 $3{\;}{\times}{\;}10^5$개를 비강으로 접종하 여 실험적 아메바성 수막뇌염을 일으킬 때 숙주의 방어기작에 대식세포가 미치는 영향을 알아 보았다. 대식세포 억제제인 silica를 마우스 복강 내로 투여한 경우의 사망율이 60.6%로 아메바만을 접종한 마우스의 사망율이 10.0%와 비하여 큰 차이를 보였으며 열처리하여 죽인 Toxoplasma gondii tachyzoites의 in vitro탐식능 관찰에서 기능을 억제시킨 대식세포의 탐식능이 3% 이하로써 아메바에 대한 복강대식세포의 기능의 저하로 인한 수막뇌염의 증가를 관찰하였다. A. culbertsoni에 대한 대식세포의 살해활동의 in vitro 실험에서 silica투여한 실험군의 복강대식세포의 뚜렷한 기능 저하를 관찰하였고, 효소표지 면역 검사법(ELISU)을 이용한 마우스 혈청 내의 $interleukin-1{\beta}(IL-1{\beta})$의 흡광도는 아메바 접종군과 생리식염수 투여군보다 silica투여를 수반한 실험군이 현저하게 낮게 나타나 대식세포가 억제되었을 때 실험적 수막뇌염이 증가함을 알 수 있었다. 결과적으로 대식세포가 A. culbertsoni 감염에 대한 숙주의 방어작용에 중요한 역할을 하는 것으로 생각된다.

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Cytopathic Change and Inflammatory Response of Human Corneal Epithelial Cells Induced by Acanthamoeba castellanii Trophozoites and Cysts

  • Sohn, Hae-Jin;Seo, Ga-Eun;Lee, Jae-Ho;Ham, A-Jeong;Oh, Young-Hwan;Kang, Heekyoung;Shin, Ho-Joon
    • Parasites, Hosts and Diseases
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    • 제57권3호
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    • pp.217-223
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    • 2019
  • Acanthamoeba castellanii has ubiquitous distribution and causes primary acanthamoebic keratitis (AK). AK is a common disease in contact lens wearers and results in permanent visual impairment or blindness. In this study, we observed the cytopathic effect, in vitro cytotoxicity, and secretion pattern of cytokines in human corneal epithelial cells (HCECs) induced by A. castellanii trophozoites and/or cysts. Morphological observation revealed that panked dendritic HCECs co-cultured with amoeba cysts had changed into round shape and gradually died. Such changes were more severe in co-culture with cyst than those of co-cultivation with trophozoites. In vitro cytotoxicity assay revealed the highest cytotoxicity to HCECs in the co-culture system with amoeba cysts. A. castellanii induced the expression of $IL-1{\alpha}$, IL-6, IL-8, and CXCL1 in HCECs. Secreted levels of $IL-1{\alpha}$, IL-6, and IL-8 in HCECs co-cultured with both trophozoites and cysts were increased at an early incubation time (3 and 6 hr). These results suggested that cytopathic changes and pro-inflammatory cytokines release of HCECs in response to A. castellanii, especially amoebic cysts, are an important mechanism for AK development.

A NATURAL TOPOLOGICAL MANIFOLD STRUCTURE OF PHASE TROPICAL HYPERSURFACES

  • Kim, Young Rock;Nisse, Mounir
    • 대한수학회지
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    • 제58권2호
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    • pp.451-471
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    • 2021
  • First, we define phase tropical hypersurfaces in terms of a degeneration data of smooth complex algebraic hypersurfaces in (ℂ∗)n. Next, we prove that complex hyperplanes are homeomorphic to their degeneration called phase tropical hyperplanes. More generally, using Mikhalkin's decomposition into pairs-of-pants of smooth algebraic hypersurfaces, we show that a phase tropical hypersurface with smooth tropicalization is naturally a topological manifold. Moreover, we prove that a phase tropical hypersurface is naturally homeomorphic to a symplectic manifold.

비접촉 조건에서의 Naegleria fowleri에 의한 표적세포의 세포독성 (Cytotoxicity of target cell against Naegleria fowleri under non-contact condition)

  • 강창근;홍일화;김종현
    • 한국동물위생학회지
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    • 제42권4호
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    • pp.169-175
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    • 2019
  • Naegleria fowleri, a pathogenic free-living amoeba, leads to a fatal infection known as primary amebic meningoencephalitis (PAM) in human and animals. PAM is an acute, fulminant, necrotizing, and hemorrhagic disease that leads to death in approximately seven days. In this study, we investigate the cytotoxicity of target cells and the secreted molecules of N. fowleri under the non-contact condition. The target cell (U87MG cell) treated with N. fowleri lysates showed no morphological changes and no cytotoxicity. By contrast, the U87MG cells co-cultured with N. fowleri trophozoites under the non-contact condition induced morphological changes and reduction in number. When U87MG cells were co-cultured with N. fowleri trophozoites under the non-contact condition for 30 min, 2 hr, and 4 hr, the levels of cytotoxicity of target cells were 32.3, 35.5, and 37.8%, respectively. Particularly, when the ratio of amoeba to target cells is 10 to 1, the level of cytotoxicity of target cells was 49.7% at 30 min. To show the proteins secreted from N. fowleri under the non-contact condition, we carried out 2D electrophoresis and observed 6 major proteins. Finally, these results suggest that the molecules released from N. fowleri under the non-contact condition induce the cell death and this process is an important step in pathogenesis of N. fowleri.

Naegleria fowleri Induces Jurkat T Cell Death via O-deGlcNAcylation

  • Lee, Young Ah;Kim, Kyeong Ah;Shin, Myeong Heon
    • Parasites, Hosts and Diseases
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    • 제59권5호
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    • pp.501-505
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    • 2021
  • The pathogenic free-living amoeba Naegleria fowleri causes primary amoebic meningoencephalitis, a fatal infection, by penetrating the nasal mucosa and migrating to the brain via the olfactory nerves. N. fowleri can induce host cell death via lytic necrosis. Similar to phosphorylation, O-linked β-N-acetylglucosamine (O-GlcNAc) glycosylation (O-GlcNAcylation) is involved in various cell-signaling processes, including apoptosis and proliferation, with O-GlcNAc addition and removal regulated by O-GlcNAc transferase and O-GlcNAcase (OGA), respectively. However, the detailed mechanism of host cell death induced by N. fowleri is unknown. In this study, we investigated whether N. fowleri can induce the modulation of O-GlcNAcylated proteins during cell death in Jurkat T cells. Co-incubation with live N. fowleri trophozoites increased DNA fragmentation. In addition, incubation with N. fowleri induced a dramatic reduction in O-GlcNAcylated protein levels in 30 min. Moreover, pretreatment of Jurkat T cells with the OGA inhibitor PUGNAc prevented N. fowleri-induced O-deGlcNAcylation and DNA fragmentation. These results suggest that O-deGlcNAcylation is an important signaling process that occurs during Jurkat T cell death induced by N. fowleri.

Involvement of NOX2-derived ROS in human hepatoma HepG2 cell death induced by Entamoeba histolytica

  • Young Ah Lee ;Myeong Heon Shin
    • Parasites, Hosts and Diseases
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    • 제61권4호
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    • pp.388-396
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    • 2023
  • Entamoeba histolytica is an enteric tissue-invasive protozoan parasite causing amoebic colitis and liver abscesses in humans. Amoebic contact with host cells activates intracellular signaling pathways that lead to host cell death via generation of caspase-3, calpain, Ca2+ elevation, and reactive oxygen species (ROS). We previously reported that various NADPH oxidases (NOXs) are responsible for ROS-dependent death of various host cells induced by amoeba. In the present study, we investigated the specific NOX isoform involved in ROS-dependent death of hepatocytes induced by amoebas. Co-incubation of hepatoma HepG2 cells with live amoebic trophozoites resulted in remarkably increased DNA fragmentation compared to cells incubated with medium alone. HepG2 cells that adhered to amoebic trophozoites showed strong dichlorodihydrofluorescein diacetate (DCF-DA) fluorescence, suggesting intracellular ROS accumulation within host cells stimulated by amoebic trophozoites. Pretreatment of HepG2 cells with the general NOX inhibitor DPI or NOX2-specific inhibitor GSK 2795039 reduced Entamoeba-induced ROS generation. Similarly, Entamoeba-induced LDH release from HepG2 cells was effectively inhibited by pretreatment with DPI or GSK 2795039. In NOX2-silenced HepG2 cells, Entamoeba-induced LDH release was also significantly inhibited compared with controls. Taken together, the results support an important role of NOX2-derived ROS in hepatocyte death induced by E. histolytica.

Molecular and biochemical characterization of a novel actin bundling protein in Acanthamoeba

  • Alafag Joanna It-itan;Moon Eun-Kyung;Hong Yeon-Chul;Chung Dong-Il;Kong Hyun-Hee
    • Parasites, Hosts and Diseases
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    • 제44권4호
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    • pp.331-341
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    • 2006
  • Actin binding proteins play key roles in cell structure and movement particularly as regulators of the assembly, stability and localization of actin filaments in the cytoplasm. In the present study, a cDNA clone encoding an actin bundling protein named as AhABP was isolated from Acanthamoeba healyi, a causative agent of granulomatous amebic encephalitis. This clone exhibited high similarity with genes of Physarum polycephalum and Dictyostelium discoideum, which encode actin bundling proteins. Domain search analysis revealed the presence of essential conserved regions, i.e., an active actin binding site and 2 putative calcium binding EF-hands. Transfected amoeba cells demonstrated that AhABP is primarily localized in phagocytic cups, peripheral edges, pseudopods, and in cortical cytoplasm where actins are most abundant. Moreover, AhABP after the deletion of essential regions formed ellipsoidal inclusions within transfected cells. High-speed co-sedimentation assays revealed that AhABP directly interacted with actin in the presence of up to $10{\mu}M$ of calcium. Under the electron microscope, thick parallel bundles were formed by full length AhABP, in contrast to the thin actin bundles formed by constructs with deletion sites. In the light of these results, we conclude that AhABP is a novel actin bundling protein that is importantly associated with actin filaments in the cytoplasm.