Synthesis of diphosphoinositide by a supernatant fraction from Acanthamoeba castellanii

1976 ◽  
Vol 54 (9) ◽  
pp. 772-777 ◽  
Author(s):  
J. Thomas Buckley
Keyword(s):  
Acanthamoeba Castellanii ◽  
Supernatant Fraction ◽  
Two Dimensional ◽  
Free Living ◽  
Low Concentrations ◽  
Free Living Amoeba

Homogenates of the free-living amoeba Acanthamoeba castellanii incorporate phosphate from [γ-32P]ATP into a lipid which co-chromatographs with diphosphoinositide on one- and two-dimensional chromatography. Incorporation into lipids similar in mobility to triphosphoinositide is not detected. The product co-chromatographs with diphosphoinositide whether exogenous phosphatidylinositol or total amoeba lipid is the substrate. The inositide kinase is almost entirely located in the supernatant fraction after centrifugation at 100 000 g. Incorporation of phosphate from [γ-32P]ATP is linear for at least 15 min in the presence of 0.5 mM phosphatidylinositol. The enzyme requires Mg2+ or Mn2+ as well as ATP and it is not affected by low concentrations of Ca2+. The apparent Km for phosphatidylinositol is 2 mM. Both ADP and cAMP inhibit the reaction.

scholarly journals Mitigation of Expression of Virulence Genes in Legionella pneumophila Internalized in the Free-Living Amoeba Willaertia magna C2c Maky

Pathogens ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 447 ◽  
Author(s):  
Rayane Mouh Mameri ◽  
Jacques Bodennec ◽  
Laurent Bezin ◽  
Sandrine Demanèche
Keyword(s):  
Gene Expression ◽  
Legionella Pneumophila ◽  
Virulence Genes ◽  
Natural Habitat ◽  
Acanthamoeba Castellanii ◽  
Severe Form ◽  
Aquatic Environments ◽  
Free Living ◽  
Intracellular Parasites ◽  
Free Living Amoeba

Legionella pneumophila is a human pathogen responsible for a severe form of pneumonia named Legionnaire disease. Its natural habitat is aquatic environments, being in a free state or intracellular parasites of free-living amoebae, such as Acanthamoeba castellanii. This pathogen is able to replicate within some amoebae. Willaertia magna C2c Maky, a non-pathogenic amoeba, was previously demonstrated to resist to L. pneumophila and even to be able to eliminate the L. pneumophila strains Philadelphia, Lens, and Paris. Here, we studied the induction of seven virulence genes of three L. pneumophila strains (Paris, Philadelphia, and Lens) within W. magna C2c Maky in comparison within A. castellanii and with the gene expression level of L. pneumophila strains alone used as controls. We defined a gene expression-based virulence index to compare easily and without bias the transcript levels in different conditions and demonstrated that W. magna C2c Maky did not increase the virulence of L. pneumophila strains in contrast to A. castellanii. These results confirmed the non-permissiveness of W. magna C2c Maky toward L. pneumophila strains.

scholarly journals Isoniazid Conjugated Magnetic Nanoparticles Loaded with Amphotericin B as a Potent Antiamoebic Agent against Acanthamoeba castellanii

Antibiotics ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 276
Author(s):  
Kawish Iqbal ◽  
Sumayah Abdelnasir Osman Abdalla ◽  
Ayaz Anwar ◽  
Kanwal Muhammad Iqbal ◽  
Muhammad Raza Shah ◽  
...  
Keyword(s):  
Magnetic Nanoparticles ◽  
Amphotericin B ◽  
Central Nervous System Infection ◽  
Acanthamoeba Castellanii ◽  
Acanthamoeba Keratitis ◽  
Free Living ◽  
Granulomatous Amoebic Encephalitis ◽  
Nano Drug Delivery ◽  
Free Living Amoeba ◽  
Acanthamoeba Species

The pathogenic free-living amoeba, Acanthamoeba castellanii, is responsible for a rare but deadly central nervous system infection, granulomatous amoebic encephalitis and a blinding eye disease called Acanthamoeba keratitis. Currently, a combination of biguanides, amidine, azoles and antibiotics are used to manage these infections; however, the host cell cytotoxicity of these drugs remains a challenge. Furthermore, Acanthamoeba species are capable of transforming to the cyst form to resist chemotherapy. Herein, we have developed a nano drug delivery system based on iron oxide nanoparticles conjugated with isoniazid, which were further loaded with amphotericin B (ISO-NPs-AMP) to cause potent antiamoebic effects against Acanthamoeba castellanii. The IC50 of isoniazid conjugated with magnetic nanoparticles and loaded with amphotericin B was found to be 45 μg/mL against Acanthamoeba castellanii trophozoites and 50 μg/mL against cysts. The results obtained in this study have promising implications in drug discovery as these nanomaterials exhibited high trophicidal and cysticidal effects, as well as limited cytotoxicity against rat and human cells.

scholarly journals Encystment Induces Down-Regulation of an Acetyltransferase-Like Gene in Acanthamoeba castellanii

Pathogens ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 321 ◽  
Author(s):  
Steven Rolland ◽  
Luce Mengue ◽  
Cyril Noël ◽  
Stéphanie Crapart ◽  
Anne Mercier ◽  
...  
Keyword(s):  
Bioinformatics Analysis ◽  
Acanthamoeba Castellanii ◽  
Acanthamoeba Keratitis ◽  
Free Living ◽  
Adverse Conditions ◽  
Genetic Modifications ◽  
Granulomatous Amoebic Encephalitis ◽  
Free Living Amoeba ◽  
Causative Agents

Acanthamoeba castellanii is a ubiquitous free-living amoeba. Pathogenic strains are causative agents of Acanthamoeba keratitis and granulomatous amoebic encephalitis. In response to adverse conditions, A. castellanii differentiate into cysts, which are metabolically inactive and resistant cells. This process, also named encystment, involves biochemical and genetic modifications that remain largely unknown. This study characterizes the role of the ACA1_384820 Acanthamoeba gene during encystment. This gene encodes a putative N-acetyltransferase, belonging to the Gcn5-related N-acetyltransferase (GNAT) family. We showed that expression of the ACA1_384820 gene was down-regulated as early as two hours after induction of encystment in A. castellanii. Interestingly, overexpression of the ACA1_384820 gene affects formation of cysts. Unexpectedly, the search of homologs of ACA1_384820 in the Eukaryota gene datasets failed, except for some species in the Acanthamoeba genus. Bioinformatics analysis suggested a possible lateral acquisition of this gene from prokaryotic cells. This study enabled us to describe a new Acanthamoeba gene that is down-regulated during encystment.

scholarly journals Legionella pneumophila Contains a Type II General Secretion Pathway Required for Growth in Amoebae as Well as for Secretion of the Msp Protease

1999 ◽  
Vol 67 (7) ◽  
pp. 3662-3666 ◽  
Author(s):  
Laura M. Hales ◽  
Howard A. Shuman
Keyword(s):  
Legionella Pneumophila ◽  
Acanthamoeba Castellanii ◽  
Gram Negative Bacteria ◽  
Type Ii ◽  
Free Living ◽  
Gram Negative ◽  
Secretion Pathway ◽  
Free Living Amoeba ◽  
Substitution Mutation

ABSTRACT We report the identification of a set of Legionella pneumophila genes that encode products with homology to proteins of the type II general secretion pathway of gram-negative bacteria. A strain containing a deletion-substitution mutation of two of these genes was unable to secrete the Msp protease. This strain was unable to multiply within the free-living amoeba Acanthamoeba castellanii yet was able to kill HL-60-derived macrophages. Because Msp is not required for growth in amoebae, other proteins which are important for growth in amoebae are likely secreted by this pathway.

scholarly journals Temperature-Dependent Parasitic Relationship between Legionella pneumophila and a Free-Living Amoeba (Acanthamoeba castellanii)

2008 ◽  
Vol 74 (14) ◽  
pp. 4585-4588 ◽  
Author(s):  
Akira Ohno ◽  
Naoyuki Kato ◽  
Ryota Sakamoto ◽  
Soichiro Kimura ◽  
Keizo Yamaguchi
Keyword(s):  
Legionella Pneumophila ◽  
Low Temperatures ◽  
Acanthamoeba Castellanii ◽  
Temperature Dependent ◽  
Free Living ◽  
Free Living Amoeba ◽  
Effects Of Temperature ◽  
Number Of Bacteria

ABSTRACT We analyzed the effects of temperature on the interaction of Legionella pneumophila with Acanthamoeba castellanii. At <20°C, overexpression of type 1 metacaspase, a stimulator of A. castellanii encystation, was associated with a reduced number of bacteria within amoeba. At low temperatures, A. castellanii seems to eliminate L. pneumophila by encystation and digestion.

Effects of harmful cyanobacteria on the freshwater pathogenic free-living amoeba Acanthamoeba castellanii

2013 ◽  
Vol 130-131 ◽  
pp. 9-17 ◽  
Author(s):  
Pablo Urrutia-Cordero ◽  
Ramsy Agha ◽  
Samuel Cirés ◽  
María Ángeles Lezcano ◽  
María Sánchez-Contreras ◽  
...  
Keyword(s):  
Acanthamoeba Castellanii ◽  
Free Living ◽  
Harmful Cyanobacteria ◽  
Free Living Amoeba

scholarly journals Vibrio cholerae O139 requires neither capsule nor LPS O side chain to grow inside Acanthamoeba castellanii

2009 ◽  
Vol 58 (1) ◽  
pp. 125-131 ◽  
Author(s):  
Hadi Abd ◽  
Amir Saeed ◽  
Andrej Weintraub ◽  
Gunnar Sandström
Keyword(s):  
Vibrio Cholerae ◽  
Acanthamoeba Castellanii ◽  
Side Chain ◽  
Wild Type ◽  
Intracellular Growth ◽  
Free Living ◽  
Growth And Survival ◽  
Free Living Amoeba ◽  
Vibrio Cholerae O139

Vibrio cholerae, the causative agent of cholera, has the ability to grow and survive in the aquatic free-living amoeba Acanthamoeba castellanii. The aim of the present study was to examine the ability of the clinical isolate V. cholerae O139 MO10 to grow in A. castellanii and to determine the effect of the bacterial capsule and LPS O side chain on intracellular growth. Results from co-cultivation, viable counts, a gentamicin assay, electron microscopy and statistical analysis showed that the association of V. cholerae O139 MO10 with A. castellanii did not inhibit growth of the amoeba, and enhanced growth and survival of V. cholerae O139 MO10 occurred. The wild-type V. cholerae O139 MO10 and a capsule mutant or capsule/LPS double mutant grew inside A. castellanii. Neither the capsule nor the LPS O side chain of V. cholerae O139 was found to play an important role in the interaction with A. castellanii, disclosing the ability of V. cholerae to multiply and survive inside A. castellanii, as well as the role of A. castellanii as an environmental host for V. cholerae.

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