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The Korean Journal of Parasitology Feb 2022The encystation of Acanthamoeba leads to the development of metabolically inactive and dormant cysts from vegetative trophozoites under unfavorable conditions. These...
The encystation of Acanthamoeba leads to the development of metabolically inactive and dormant cysts from vegetative trophozoites under unfavorable conditions. These cysts are highly resistant to anti-Acanthamoeba drugs and biocides. Therefore, the inhibition of encystation would be more effective in treating Acanthamoeba infection. In our previous study, a sirtuin family protein-Acanthamoeba silent-information regulator 2-like protein (AcSir2)-was identified, and its expression was discovered to be critical for Acanthamoeba castellanii proliferation and encystation. In this study, to develop Acanthamoeba sirtuin inhibitors, we examine the effects of sirtinol, a sirtuin inhibitor, on trophozoite growth and encystation. Sirtinol inhibited A. castellanii trophozoites proliferation (IC50=61.24 μM). The encystation rate of cells treated with sirtinol significantly decreased to 39.8% (200 μM sirtinol) after 24 hr of incubation compared to controls. In AcSir2-overexpressing cells, the transcriptional level of cyst-specific cysteine protease (CSCP), an Acanthamoeba cysteine protease involved in the encysting process, was 11.6- and 88.6-fold higher at 48 and 72 hr after induction of encystation compared to control. However, sirtinol suppresses CSCP transcription, resulting that the undegraded organelles and large molecules remained in sirtinol-treated cells during encystation. These results indicated that sirtinol sufficiently inhibited trophozoite proliferation and encystation, and can be used to treat Acanthamoeba infections.
Topics: Acanthamoeba castellanii; Animals; Benzamides; Cell Proliferation; Naphthols; Sirtuins; Trophozoites
PubMed: 35247948
DOI: 10.3347/kjp.2022.60.1.1 -
Biomedicine & Pharmacotherapy =... Jun 2022The genus Acanthamoeba is characterized by being a group of ubiquitous and free-living amoebae that inhabit a variety of environments. Generally, human infections by...
The genus Acanthamoeba is characterized by being a group of ubiquitous and free-living amoebae that inhabit a variety of environments. Generally, human infections by this parasite are associated with Acanthamoeba keratitis, especially in contact lens wearers, and with chronic but fatal granulomatous amoebic meningoencephalitis. Current treatments used for eradication of amoeba from infection sites represent a challenge for pharmacotherapy, due to the lack of effective treatment and the amoebae highly resistant to anti-amoebic drugs. In this study, we describe the results of the assessment of the IC of 10 isobenzofuran-1(3H)-one derivatives (QOET) against four Acanthamoeba strains. The compounds QOET-3 and QOET-9 were the selected derivatives with the lowest IC in A. castellanii Neff trophozoites (73.71 ± 0.25 and 69.99 ± 15.32 µM, respectively). Interestingly, analysis of the compound effects on the cell apoptosis-like features showed that both active molecules triggered programmed cell death (PCD) in A. castellanii Neff. The results obtained in this study highlights that isobenzofuranone derivatives could represent an interesting source for developing novel antiamoebic drugs.
Topics: Acanthamoeba Keratitis; Acanthamoeba castellanii; Amebicides; Animals; Cell Death; Humans; Trophozoites
PubMed: 35658232
DOI: 10.1016/j.biopha.2022.113062 -
Microbiology (Reading, England) Feb 2022The ubiquitous unicellular eukaryote, , is known to play a role in the survival and dissemination of is the leading cause of bacterial foodborne gastroenteritis...
The ubiquitous unicellular eukaryote, , is known to play a role in the survival and dissemination of is the leading cause of bacterial foodborne gastroenteritis world-wide and is a major public health problem. The ability of to interact and potentially invade epithelial cells is thought to be key for disease development in humans. We examined grown under standard laboratory conditions, 11168H with that harvested from within (11168H) or (11168H), and compared their ability to invade different cell lines. harvested from within amoebae had a ~3.7-fold increase in invasiveness into T84 human epithelial cells and a striking ~11-fold increase for re-entry into cells. We also investigated the invasiveness and survivability of six diverse representative strains within spp., our results confirm that invasion and survivability is likely host-cell-dependent. Our survival assay data led us to conclude that spp. are a transient host for and that survival within amoebae pre-adapts and enhances subsequent cell invasion. This study provides new insight into interactions with amoebae and its increased invasiveness potential in mammalian hosts.
Topics: Acanthamoeba castellanii; Amoeba; Animals; Campylobacter Infections; Campylobacter jejuni; Eukaryota; Humans; Mammals
PubMed: 35175913
DOI: 10.1099/mic.0.001143 -
Scientific Reports Jan 2020Acanthamoeba spp. are predominant free-living amoebae of water and soil. They have been used as tools for the isolation and culture of microbes that resist after their...
Acanthamoeba spp. are predominant free-living amoebae of water and soil. They have been used as tools for the isolation and culture of microbes that resist after their phagocytosis, such as Legionella-like bacteria, and, more recently giant viruses for which differences in permissiveness have been reported. However, problems have been reported regarding their identification at the species level. The present work implemented specific PCR systems for the detection and identification of Acanthamoeba species through comparison of sequences and phylogenetic analyses. Thirty-three Acanthamoeba isolates were studied, including 20 reference strains and 13 isolates retrieved from water, soil or clinical samples. Previous delineation of a core genome encompassing 826 genes based on draft genome sequences from 14 Acanthamoeba species allowed designing PCR systems for one of these core genes that encodes an alanine-tRNA ligase. These primers allowed an efficient and specific screening to detect Acanthamoeba presence. In addition, they identified all 20 reference strains, while partial and complete sequences coding for 18S ribosomal RNA identified only 11 (55%). We found that four isolates may be considered as new Acanthamoeba species. Consistent with previous studies, we demonstrated that some Acanthamoeba isolates were incorrectly assigned to species using the 18S rDNA sequences. Our implemented tool may help determining which Acanthamoeba strains are the most efficient for the isolation of associated microorganisms.
Topics: Acanthamoeba; Acanthamoeba castellanii; Alanine-tRNA Ligase; Genes, Protozoan; Phylogeny; Polymerase Chain Reaction; RNA, Ribosomal, 18S
PubMed: 32005846
DOI: 10.1038/s41598-020-57998-5 -
Cornea May 2023Acanthamoeba castellanii ( A. castellanii ) displays host specificity at the level of the ocular surface. This study determined the susceptibility of the intact and...
PURPOSE
Acanthamoeba castellanii ( A. castellanii ) displays host specificity at the level of the ocular surface. This study determined the susceptibility of the intact and traumatized feline cornea to A. castellanii binding and invasion relative to other host species with established susceptibility and resistance to Acanthamoeba binding.
METHODS
Full-thickness buttons of fresh feline, porcine, and canine corneas were prepared. The corneal epithelium was confirmed intact by fluorescein staining or lightly scarified with a 25-G needle to simulate corneal trauma. Acanthamoeba castellanii was axenically cultivated. Corneal buttons were incubated with the parasite suspension or parasite-free medium for 18 hours at 35°C. Corneal buttons were rinsed, fixed, and processed for histopathology and immunohistochemistry using immunoperoxidase and immunofluorescence methods of amoeba detection.
RESULTS
Numerous amoebae were bound to feline and porcine corneas incubated with parasites. In both intact and traumatized corneas, amoebae were detected at all levels in the corneal epithelium and within the anterior stroma. In traumatized corneal sections, amoebae were frequently present in regions of epithelial damage. Corneal architecture was well-preserved in sections incubated with parasite-free medium; however, epithelial cell sloughing, separation of epithelial layers, and epithelial detachment from the stroma were observed in corneas incubated with amoebae. Intact and traumatized canine corneas were relatively free of adherent amoebae, and corneal architecture was indistinguishable between sections incubated with the parasite suspension and parasite-free medium.
CONCLUSIONS
The feline cornea is highly susceptible to in vitro binding and invasion by A. castellanii . Acanthamoeba binding to the feline cornea does not require a previous epithelial defect.
Topics: Animals; Cats; Dogs; Swine; Acanthamoeba castellanii; Cornea; Epithelium, Corneal; Acanthamoeba Keratitis; Corneal Injuries
PubMed: 36518074
DOI: 10.1097/ICO.0000000000003220 -
International Journal of Molecular... Aug 2023Uncoupling proteins (UCPs) are mitochondrial inner membrane transporters that mediate free-fatty-acid-induced, purine-nucleotide-inhibited proton leak into the...
Uncoupling proteins (UCPs) are mitochondrial inner membrane transporters that mediate free-fatty-acid-induced, purine-nucleotide-inhibited proton leak into the mitochondrial matrix, thereby uncoupling respiratory substrate oxidation from ATP synthesis. The aim of this study was to provide functional evidence that the putative gene of the free-living protozoan amoeba, , encodes the mitochondrial protein with uncoupling activity characteristic of UCPs and to investigate its role during oxidative stress. We report the sequencing and cloning of a complete coding sequence, its phylogenetic analysis, and the heterologous expression of AcUCP in the strain Measurements of mitochondrial respiratory activity and membrane potential indicate that the heterologous expression of AcUCP causes AcUCP-mediated uncoupling activity. In addition, in a model of oxidative stress with increased reactive oxygen species levels (superoxide dismutase 1 knockout yeasts), AcUCP expression strongly promotes cell survival and growth. The level of superoxide anion radicals is greatly reduced in the Δ strain expressing AcUCP. These results suggest that AcUCP targeted to yeast mitochondria causes uncoupling and may act as an antioxidant system. Phylogenetic analysis shows that the UCP diverges very early from other UCPs, but clearly locates within the UCP subfamily rather than among other mitochondrial anion carrier proteins.
PubMed: 37569876
DOI: 10.3390/ijms241512501 -
International Journal of Biological... 2018Amoebozoans are in many aspects interesting research objects, as they combine features of single-cell organisms with complex signaling and defense systems, comparable to...
Amoebozoans are in many aspects interesting research objects, as they combine features of single-cell organisms with complex signaling and defense systems, comparable to multicellular organisms. is a cosmopolitan species and developed diverged feeding abilities and strong anti-bacterial resistance; is a parasitic amoeba, who underwent massive gene loss and its genome is almost twice smaller than that of . Nevertheless, both species prosper, demonstrating fitness to their specific environments. Here we compare transcriptomes of and with application of orthologs' search and gene ontology to learn how different life strategies influence genome evolution and restructuring of physiology demonstrates great metabolic activity and plasticity, while reveals several interesting features in its translational machinery, cytoskeleton, antioxidant protection, and nutritional behavior. In addition, we suggest new features in physiology that may explain its successful colonization of human colon and may facilitate medical research.
Topics: Acanthamoeba castellanii; Actins; Adaptation, Physiological; Comparative Genomic Hybridization; Entamoeba histolytica; Gene Expression; Genes, Protozoan; Sequence Analysis, RNA; Transcriptome
PubMed: 29559848
DOI: 10.7150/ijbs.23869 -
The Lancet. Infectious Diseases Feb 2022Amoebic encephalitis is a rare cause of CNS infection for which mortality exceeds 90%. We present the case of a 27-year-old man with AIDS who presented to a hospital in... (Review)
Review
Amoebic encephalitis is a rare cause of CNS infection for which mortality exceeds 90%. We present the case of a 27-year-old man with AIDS who presented to a hospital in Atlanta (Georgia, USA) with tonic-clonic seizures and headache. His clinical condition deteriorated over several days. Brain biopsy revealed lymphohistiocytic inflammation and necrosis with trophozoites and encysted forms of amoebae. Immunohistochemical and PCR testing confirmed Acanthamoeba castellanii encephalitis, typically described as granulomatous amoebic encephalitis (GAE). No proven therapy for GAE is available, although both surgical and multiagent antimicrobial treatment strategies are often used. Most recently, these include the antileishmanial agent miltefosine. Here we review all cases of GAE due to Acanthamoeba spp in people with HIV/AIDS identified in the literature and reported to the Centers for Disease Control and Prevention. We describe this case as a reminder to the clinician to consider protozoal infections, especially free-living amoeba, in the immunocompromised host with a CNS infection refractory to traditional antimicrobial therapy.
Topics: Acanthamoeba castellanii; Acquired Immunodeficiency Syndrome; Adult; Amebiasis; Antiprotozoal Agents; Encephalitis; Granuloma; Humans; Male
PubMed: 34461057
DOI: 10.1016/S1473-3099(20)30933-6 -
Journal of Microbiology and... May 2019belonging to the T4 genotype may cause a fatal brain infection known as granulomatous amoebic encephalitis, and the vision-threatening eye infection keratitis. The aim...
belonging to the T4 genotype may cause a fatal brain infection known as granulomatous amoebic encephalitis, and the vision-threatening eye infection keratitis. The aim of this study was to evaluate the antiamoebic effects of three clinically available antidiabetic drugs, Glimepiride, Vildagliptin and Repaglinide, against belonging to the T4 genotype. Furthermore, we attempted to conjugate these drugs with silver nanoparticles (AgNPs) to enhance their antiamoebic effects. Amoebicidal, encystation, excystation, and host cell cytotoxicity assays were performed to unravel any antiacanthamoebic effects. Vildagliptin conjugated silver nanoparticles (Vgt-AgNPs) characterized by spectroscopic techniques and atomic force microscopy were synthesized. All three drugs showed antiamoebic effects against and significantly blocked the encystation. These drugs also showed significant cysticidal effects and reduced host cell cytotoxicity caused by . Moreover, Vildagliptin-coated silver nanoparticles were successfully synthesized and are shown to enhance its antiacanthamoebic potency at significantly reduced concentration. The repurposed application of the tested antidiabetic drugs and their nanoparticles against free-living amoeba such as described here is a novel outcome that holds tremendous potential for future applications against devastating infection.
Topics: Acanthamoeba castellanii; Amebicides; Anti-Infective Agents; Carbamates; HeLa Cells; Humans; Hypoglycemic Agents; Metal Nanoparticles; Nanoconjugates; Piperidines; Silver; Sulfonylurea Compounds; Vildagliptin
PubMed: 31030451
DOI: 10.4014/jmb/1903.03009 -
Arhiv Za Higijenu Rada I Toksikologiju Sep 2020Acanthamoeba is an opportunistic protozoon, widespread in the aquatic environment, where it can be in endosymbiosis with over 30 pathogenic bacteria, including...
Acanthamoeba is an opportunistic protozoon, widespread in the aquatic environment, where it can be in endosymbiosis with over 30 pathogenic bacteria, including nontuberculous mycobacteria (NTM). Protozoa play a crucial role in mycobacterial pathogenesis and serve as a reservoir of infection. Since the first step in bacteria making contact with amoebae is adhesion, we were interested in investigating whether essential oils (EOs) can affect it. To that end we investigated the effects of juniper (Juniperus communis) and immortelle (Helichrysum italicum) EOs against Mycobacterium avium, M. intracellulare, and M. gordonae in tap water and against their adhesion to Acanthamoeba castellanii by combining them in synergistic EO concentrations. M. avium and M. intracellulare adhered to A. castellanii to a greater extent than M. gordonae. The adhesion of all NTMs was prevented by the subinhibitory concentrations of EOs. When comparing the effect of synergistic combinations of EOs and the effect of a single concentration from a combination, a higher percentage of adhesion inhibition in all synergistic combinations observed, except against M. gordonae. Neither oil was cytotoxic to A. castellanii. Our findings suggest that the EOs or their components weaken the contact of environmental NTMs and free-living amoebae and indirectly diminish their pathogenic potential, which could be of value in developing strategies for maintenance of water supply systems.
Topics: Acanthamoeba castellanii; Juniperus; Mycobacterium avium; Nontuberculous Mycobacteria; Oils, Volatile
PubMed: 33074171
DOI: 10.2478/aiht-2020-71-3442