Gene silencing of nfa1 affects the in vitro cytotoxicity of Naegleria fowleri in murine macrophages.

The gene nfa1 was isolated from the free-living pathogenic amoeba Naegleria fowleri. The protein Nfa1 is located in pseudopodia and specifically in food-cups. It is also involved in cytotoxicity.

Effect of therapeutic chemical agents in vitro and on experimental meningoencephalitis due to Naegleria fowleri.

Naegleria fowleri is a ubiquitous, pathogenic free-living amoeba; it is the most virulent Naegleria species and causes primary amoebic meningoencephalitis (PAME) in laboratory animals and humans. Although amphotericin B is currently the only agent available for the treatment of PAME, it is a very toxic antibiotic and may cause many adverse effects on other organs. In order to find other potentially therapeutic agents for N.

Therapeutic effect of rokitamycin in vitro and on experimental meningoencephalitis due to Naegleria fowleri.

Inhalation of freshwater containing the free-living amoeba Naegleria fowleri leads to a potentially fatal infection known as primary amoebic meningoencephalitis (PAME). Amphotericin B is the only agent with clinical efficacy in the treatment of PAME in humans, however this drug is often associated with adverse effects on the kidney and other organs. In an attempt to select other useful therapeutic agents for treating PAME, the amoebicidal activities of antibacterial agents including clarithromycin, erythromycin, hygromycin B, neomycin, rokitamycin, roxithromycin and zeocin were examined.

Naegleria fowleri: nfa1 gene knock-down by double-stranded RNAs.

Nfa1 protein expressed by the nfa1 gene that was cloned recently from pathogenic Naegleria fowleri was found in pseudopodia, especially food-cups, and concerned with a mechanism of pathogenicity of N. fowleri. In the present study, N.

Involvement of beta 2-integrin in ROS-mediated neutrophil apoptosis induced by Entamoeba histolytica.

Cellular adhesion through beta 2-integrin (CD18) is an important step in signal transduction leading to apoptosis of human neutrophils, and NADPH oxidase-derived reactive oxygen species (ROS) are essential for neutrophil apoptosis induced by Entamoeba histolytica. Therefore, we investigated the role of beta 2-integrin-mediated signals in ROS-dependent neutrophil apoptosis induced by E. histolytica.

Molecular cloning and characterization of a cytosolic heat shock protein 70 from Naegleria fowleri.

A gene encoding a cytosolic heat shock protein 70 from pathogenic Naegleria fowleri (Nf-cHSP70) was identified. The Nf-cHSP70 was 2,062 bp in length with an open reading frame of 1,980 bp encoding 659 amino acid residues. The deduced amino acid sequence of the gene shared high sequence identities with HSP70s from other parasitic organisms and mammals.

Identification of differentially expressed cDNAs in Acanthamoeba culbertsoni after mouse brain passage.

Free-living amoebae of the genus Acanthamoeba are causative agents of granulomatous amebic encephalitis and amebic keratitis. Because the virulence of Acanthamoeba culbertsoni cultured in the laboratory is restored by consecutive brain passages, we examined the genes induced in mouse brain-passaged A. culbertsoni by differential display reverse transcriptase polymerase chain reaction (DDRT-PCR).

Naegleria fowleri: functional expression of the Nfa1 protein in transfected Naegleria gruberi by promoter modification.

To establish a transient transfection system in a Naegleria, we constructed three nfa1-pEGFP-N1 vectors by the promoter replacement and insertion of a nfa1 gene and transfected the DNAs into Naegleria gruberi using a lipid reagent. The transfection efficiency and usefulness of the three modified vectors were estimated by identifying the expressions of the EGFP and Nfa1 protein from N. gruberi.

Expression of the nfa1 gene cloned from pathogenic Naegleria fowleri in nonpathogenic N. gruberi enhances cytotoxicity against CHO target cells in vitro.

The pathogenic amoeba Naegleria fowleri has a 360-bp nfa1 gene that encodes the Nfa1 protein (13.1 kDa), which is located in the pseudopodia of the amoeba, and an anti-Nfa1 antibody reduces N. fowleri-induced mammalian-cell cytotoxicity in vitro.

NADPH oxidase-derived reactive oxygen species-mediated activation of ERK1/2 is required for apoptosis of human neutrophils induced by Entamoeba histolytica.

The extracellular tissue penetrating protozoan parasite Entamoeba histolytica has been known to induce host cell apoptosis. However, the intracellular signaling mechanism used by the parasite to trigger apoptosis is poorly understood. In this study, we investigated the roles of reactive oxygen species (ROS), and of MAPKs in the Entamoeba-induced apoptosis of human neutrophils.

Ultrastructural observation of human neutrophils during apoptotic cell death triggered by Entamoeba histolytica.

Neutrophils are important effector cells against protozoan extracellular parasite Entamoeba histolytica, which causes amoebic colitis and liver abscess in human beings. Apoptotic cell death of neutrophils is an important event in the resolution of inflammation and parasite's survival in vivo. This study was undertaken to investigate the ultrastructural aspects of apoptotic cells during neutrophil death triggered by Entamoeba histolytica.

Pathogenic free-living amoebae in Korea.

Acanthamoeba and Naegleria are widely distributed in fresh water, soil and dust throughout the world, and cause meningoencephalitis or keratoconjunctivitis in humans and other mammals. Korean isolates, namely, Naegleria sp. YM-1 and Acanthamoeba sp.

The involvement of an integrin-like protein and protein kinase C in amoebic adhesion to fibronectin and amoebic cytotoxicity.

Adherence of a pathogen to the host cell is one of the critical steps in microbial infections. Naegleria fowleri, a causative agent of primary amoebic meningoencephalitis in humans, is expected to interact with extracellular components of the host, such as fibronectin, in a receptor-mediated mode. In this study, we investigated the interaction between N.

Decreasing effect of an anti-Nfa1 polyclonal antibody on the in vitro cytotoxicity of pathogenic Naegleria fowleri.

The nfa1 gene was cloned from a cDNA library of pathogenic Naegleria fowleri by immunoscreening; it consisted of 360 bp and produced a 13.1 kDa recombinant protein (rNfa1) that showed the pseudopodia-specific localization by immunocytochemistry in the previous study. Based on the idea that the pseudopodia-specific Nfa1 protein mentioned above seems to be involved in the pathogenicity of N.

Acanthamoeba sohi, n. sp., a pathogenic Korean isolate YM-4 from a freshwater fish.

A new species of Acanthamoeba was isolated from a freshwater fish in Korea and tentatively named Acanthamoeba sp. YM-4 (Korean isolate YM-4). The trophozoites were 11.

Immunological characterizations of a cloned 13.1-kilodalton protein from pathogenic Naegleria fowleri.

We previously cloned an antigenic gene (named nfa1) from a cDNA library of Naegleria fowleri by immunoscreening. The nfa1 gene had a coding nucleotide sequence consisting of 357 bases and produced a recombinant 13.1-kDa protein (Nfa1).

Gordius worm found in a three year old girl's vomitus.

Since the Gordius worm is a parasite of crickets and several arthropods, cases of humans infected with this worm have been rare and accidental. A Gordius worm was obtained from a three-year-old girl who consulted a local clinic in Gwangju, Kyunggi-do, Korea. She lived in a rural area, and had eaten an insect that looked like a cricket.

A survey on head lice infestation in Korea (2001) and the therapeutic efficacy of oral trimethoprim/sulfamethoxazole adding to lindane shampoo.

Total of 7,495 children including 3,908 boys and 3,587 girls from a kindergarten and 15 primary schools were examined for head lice infestation (HLI). The overall prevalence of HLI in this study was found to be 5.8%.

Phylogenetic relationship of ribosomal ITS2 and mitochondrial COI among diploid and triploid Paragonimus westermani isolates.

We compared patterns of intraspecific polymorphism of two markers with contrasting modes of evolution, nuclear ribosomal DNA (rDNA) and mitochondrial DNA (mtDNA), in the lung fluke, diploid and triploid Paragonimus westermani from three geographical regions of Korea. The genetic distances between three populations of Korean diploid and triploid P. westermani showed no significant difference in the nucleotide sequences of the mitochondrial cytochrome c oxidase subunit I (mtCOI) and ribosomaal second internal transcribed spacer (ITS2) genes.

A case of breast sparganosis.

A 29-year-old Korean woman visited the Department of Surgery in MizMedi Hospital with a palpable itching mass on the right breast that had existed for the past 7 months. She had no history to eat either frogs or snakes, but had the history of drinking impure water. Sonography revealed a serpiginous hypoechoic tubular structure associated with partial fat necrosis in breast parenchymal layer and subcutaneous fat layer.

Status of intestinal parasites infection among primary school children in Kampongcham, Cambodia.

A survey was made to find the extent of intestinal parasite infection in Kampongcham, Cambodia in February 2002. A total of 251 fecal specimens were collected from Tonlebat primary school children and examined by formalin-ether sedimentation technique. The overall infection rate of intestinal parasite was 54.

Characterization of two glyceraldehyde 3-phosphate dehydrogenase genes in Giardia lamblia.

We investigated two putative gap genes encoding glyceraldehyde 3-phosphate dehydrogenase (GAPDH) in Giardia lamblia. While the expression of the gap2 gene was induced during encystation, gap1 was constitutively expressed. The induction of GAP2 protein during encystation was confirmed using GAP2-specific polyclonal antibodies.

[Passive immunity by splenocyte transfer against amebic meningoencephalitis in mice].

The role of passive cell-mediated transfer of immunity against primary amoebic meningoencephalitis(PAME) in mice was studied. Naegleria fowleri, ITMAP 359, were cultured in CGVS medium. The ICR mice used were six week-old males of average weight of 15 g.

[A comparative study on hydrolase activities in Acanthamoeba culbertsoni and A. royreba].

Specific or non-specific cytolytic processes of free-living amoebae causing meningoencephalitis have been emphasized and the cytolytic ability related to hydrolases in Entamoeba sp. and Naegleria sp. has also been reported since the latter half of 1970's.