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Genomics Aug 2009Free-living amoebae act as environmental hosts of several intracellular pathogens. We examined the interaction between Acanthamoeba rhysodes and Salmonella, a human...
Free-living amoebae act as environmental hosts of several intracellular pathogens. We examined the interaction between Acanthamoeba rhysodes and Salmonella, a human intracellular pathogen. There was no difference among three different serovars of Salmonella in terms of their growth within A. rhysodes over time. The number of intracellular bacteria increased at 6 h post-infection, and the viability of A. rhysodes was significantly reduced at 24 h post-infection. Amoebic cell death was characterized by TUNEL and Annexin V assay, without DNA ladder identified, indicating an apoptosis-like cell death in Salmonella-infected A. rhysodes. Global gene expression screening between intracellular and extracellular Salmonella by microarray and quantitative PCR showed that genes from Salmonella pathogenicity islands and virulence plasmid were up-regulated within A. rhysodes. The phase-dependent expression pattern suggests their distinct roles in the pathogenesis. A. rhysodes and Salmonella provide a model to study transient symbiosis between bacterial pathogens and protozoa in an aquatic ecosystem.
Topics: Acanthamoeba; Animals; Apoptosis; Gene Expression Regulation, Bacterial; Microbial Viability; Salmonella typhimurium
PubMed: 19446019
DOI: 10.1016/j.ygeno.2009.05.004 -
Applied and Environmental Microbiology Jun 2004The ability of salmonellae to become internalized and to survive and replicate in amoebae was evaluated by using three separate serovars of Salmonella enterica and five...
The ability of salmonellae to become internalized and to survive and replicate in amoebae was evaluated by using three separate serovars of Salmonella enterica and five different isolates of axenic Acanthamoeba spp. In gentamicin protection assays, Salmonella enterica serovar Dublin was internalized more efficiently than Salmonella enterica serovar Enteritidis or Salmonella enterica serovar Typhimurium in all of the amoeba isolates tested. The bacteria appeared to be most efficiently internalized by Acanthamoeba rhysodes. Variations in bacterial growth conditions affected internalization efficiency, but this effect was not altered by inactivation of hilA, a key regulator in the expression of the invasion-associated Salmonella pathogenicity island 1. Microscopy of infected A. rhysodes revealed that S. enterica resided within vacuoles. Prolonged incubation resulted in a loss of intracellular bacteria associated with morphological changes and loss of amoebae. In part, these alterations were associated with hilA and the Salmonella virulence plasmid. The data show that Acanthamoeba spp. can differentiate between different serovars of salmonellae and that internalization is associated with cytotoxic effects mediated by defined Salmonella virulence loci.
Topics: Acanthamoeba; Animals; Bacterial Proteins; Cell Line; Colony Count, Microbial; Culture Media; Dogs; Humans; Microscopy, Electron; Salmonella enterica; Trans-Activators; Virulence
PubMed: 15184177
DOI: 10.1128/AEM.70.6.3706-3714.2004 -
The Korean Journal of Parasitology Mar 2005The taxonomy of Acanthamoeba spp., an amphizoic amoeba which causes granulomatous amoebic encephalitis and chronic amoebic keratitis, has been revised many times. The...
Evaluation of taxonomic validity of four species of Acanthamoeba: A. divionensis, A. paradivionensis, A. mauritaniensis, and A. rhysodes, inferred from molecular analyses.
The taxonomy of Acanthamoeba spp., an amphizoic amoeba which causes granulomatous amoebic encephalitis and chronic amoebic keratitis, has been revised many times. The taxonomic validity of some species has yet to be assessed. In this paper, we analyzed the morphological characteristics, nuclear 18s rDNA and mitochondrial 16s rDNA sequences and the Mt DNA RFLP of the type strains of four Acanthamoeba species, which had been previously designated as A. divionensis, A. parasidionensis, A. mauritaniensis, and A. rhysodes. The four isolates revealed characteristic group II morphology. They exhibited 18S rDNA sequence differences of 0.2-1.1% with each other, but more than 2% difference from the other compared reference strains. Four isolates formed a different clade from that of A. castellanii Castellani and the other strains in morphological group II on the phylogenetic tree. In light of these results, A. paradivionensis, A. divionensis, and A. mauritaniensis should be regarded as synonyms for A. rhysodes.
Topics: Acanthamoeba; Animals; DNA, Mitochondrial; DNA, Ribosomal; Phylogeny; Polymorphism, Restriction Fragment Length; RNA, Ribosomal, 18S
PubMed: 15793353
DOI: 10.3347/kjp.2005.43.1.7 -
Journal of Ophthalmic Nursing &... 19931. Acanthamoeba keratitis is an uncommon but increasingly prevalent infection with the potential to cause severe ocular damage. Acanthamoeba is a nonflagellated...
1. Acanthamoeba keratitis is an uncommon but increasingly prevalent infection with the potential to cause severe ocular damage. Acanthamoeba is a nonflagellated free-living amoeba that is ubiquitous in the environment. The most common type is A castellani, but A polyphagia, A rhysodes, A culbertson, and A hatchetti have been isolated from infected eyes. 2. Clinical features include foreign body sensation, blurred vision, tearing, and photophobia. There is minimal pain in the early stages of infection, but severe pain is a manifestation of the advanced stages of the disease. 3. The incidence of Acanthamoeba keratitis appears to be decreasing because of increased awareness, but education emphasizing proper lens sterilization is essential and should be carried out when contact lenses are first dispensed.
Topics: Acanthamoeba Keratitis; Humans; Primary Prevention; Prognosis
PubMed: 8158668
DOI: No ID Found -
Iranian Journal of Parasitology 2014The free-living amoebae Acanthamoeba spp. have been recognized as etiologic agents of amoebic encephalitis, keratitis, otitis, lung lesions and other skin infections...
BACKGROUND
The free-living amoebae Acanthamoeba spp. have been recognized as etiologic agents of amoebic encephalitis, keratitis, otitis, lung lesions and other skin infections mainly in immuno-compromised individuals. The purpose of this study is to detect the presence of Acanthamoeba in swimming pools in Egypt using a polymerase chain reaction (PCR) method.
METHODS
Water samples were collected from 10 different swimming pools in Cairo, Egypt. Samples were cultured on non-nutrient agar for the detection of Acanthamoeba isolates that were confirmed by PCR amplification using genus specific primers. The molecularly confirmed Acanthamoeba isolates were morphologically identified to the species level.
RESULTS
Members of genus Acanthamoeba were detected in 49.2% of the examined swimming-pool water samples. Morphologically, six Acanthamoeba species were isolated from the examined swimming pool water namely A. polyphaga, A.castellanii, A. rhysodes, A. mauritaniensis, A. royreba and A. triangularis. All the identified species of Acanthamoeba were molecularly confirmed to be related to the genus Acanthamoeba.
CONCLUSION
The isolated species of Acanthamoeba could provoke variable degrees of infections to the swimmers. The culture method is cheaper and easier than PCR techniques that are faster for the detection of free-living amoebae.
PubMed: 25848385
DOI: No ID Found -
Nature Jul 1970
Topics: Cell Division; Cell Nucleus; Colchicine; Culture Media; Eukaryota; Microscopy, Electron; Mitosis; Peptones; Stimulation, Chemical
PubMed: 5428435
DOI: 10.1038/227379b0 -
Global prevalence of free-living amoebae in solid matrices - A systematic review with meta-analysis.Acta Tropica Nov 2023The ubiquitous free-living amoebae (FLA) are microorganisms of significant medical, sanitary, and ecological importance. However, their characterization within solid... (Meta-Analysis)
Meta-Analysis Review
The ubiquitous free-living amoebae (FLA) are microorganisms of significant medical, sanitary, and ecological importance. However, their characterization within solid matrices such as soil, dust, sediment, mud, sludge, and compost remain to be systematized. In this study, we conducted a systematic review with meta-analysis to explore the global distribution of FLA in solid matrices. From the analysis of 104 out of 4,414 scientific articles retrieved from different databases, it was found that the general global prevalence of FLA in solid matrices was of 55.13% (95% confidence interval (CI) 49.32-60.94). Specifically, FLA prevalence was high in soil (72.40%, 95% CI 69.08-75.73), sediment (57.91%, 95% CI 50.01-65.81), mud (52.90%, 95% CI 24.01-81.78), dust (48.60%, 95% CI 43.00-54.19), and sewage sludge (40.19%, 95% CI 30.68-49.70). In aerosols it was comparatively lower (17.21%, 95% CI 12.76-21.66). Acanthamoeba spp. (52.23%) and Hartmanella/Vermamoeba spp. (36.06%) were found to be more prevalent, whereas Naegleria spp. (34.98%) and Balamuthia spp. (27.32%) were less prevalent. The distribution of the highest global prevalence values for species of Acanthamoeba spp., considering different publication periods of the studies, is as follows: A. hatchetti (51.46%), A. rhysodes (47.49%), A. polyphaga (36.37%), A. culbertsoni (34.31%), A. castellanii (34.21%), and A. lenticulata (32.82%). For other FLA species, the distribution is: Hartmannella/Vermamoeba vermiformis (91.57%), Naegleria fowleri (42.32%), Naegleria gruberi (32.39%), and Balamuthia mandrillaris (25%). The most prevalent Acanthamoeba genotypes were T4 (33.38%) and T3 (23.94%). Overall, the global prevalence of FLA in solid matrices is as high as or greater than that reported in water by previous systematic reviews. Thus, actions aimed at reducing exposure to FLA or exploring their ecological dynamics should consider not only water but also the various solid matrices. The finding outlined here can provide valuable insights for such actions, e.g., informing on the level of exposure to FLA, or on the microbial biodiversity of specific environmental compartments.
Topics: Animals; Amoeba; Prevalence; Sewage; Acanthamoeba; Coleoptera; Dust; Soil; Water
PubMed: 37633571
DOI: 10.1016/j.actatropica.2023.107006 -
Lipids Apr 2014Ether lipids were identified among components liberated with HF and nitrous acid deamination from Acanthamoeba rhysodes whole cells and its membrane...
Ether lipids were identified among components liberated with HF and nitrous acid deamination from Acanthamoeba rhysodes whole cells and its membrane glycoinositolphospholipids (GIPL). Liberated ether glycerols were converted to various derivatives that served characterization thereof. These included TMS and isopropylidene derivatives, oxidation with sodium periodate to aldehyde followed by reduction with NaBH4 to alcohol, and reaction of the alcohol with acetic anhydrite to form acetate derivatives. Periodate sensitivity demonstrated that the alkyl side chains were linked to the sn-1 position of glycerol. Combined information from TLC, GC-MS analysis, MALDI-TOF spectrometry, and chemical degradation experiments indicated the presence of ether-linked saturated normal and branched hydrocarbons with a length of C20-23 in the phospholipid fraction, C20-24 in free GPI, and C21-23 in the LPG polymer. The distribution of particular classes of alkylglycerols was similar for phospholipid and GPI fractions, and amounted to 2.62% (±0.04-0.28) 1-O-eicosanyl-sn-glycerol, 16.66% (±0.32-1.1) 1-O-uncosanyl-sn-glycerol, 9.18% (±0.33-1.37) anteiso-1-O-docosanyl-sn-glycerol, 47.56% (±0.32-2.14) 1-O-docosanyl-sn-glycerol, 20.56% (±0.58-1.67) anteiso-1-O-tricosanyl-sn-glycerol, and 2.34% (±0.12-0.63) 1-O-tricosanyl-sn-glycerol. For LPG preparation, the most abundant were anteiso-1-O-tricosanyl-sn-glycerol (57.26%) and 1-O-docosanyl-sn-glycerol (30.12%). The data from TLC and GC-MS analysis showed that ether lipids from phospholipids probably represent the lyso-alkylglycerol type, while those derived from GIPL are alkylacylglycerol moieties.
Topics: Acanthamoeba; Ethers; Gas Chromatography-Mass Spectrometry; Glycerol; Glycolipids; Membrane Lipids; Phospholipids
PubMed: 24535098
DOI: 10.1007/s11745-014-3884-9 -
Archives of Ophthalmology (Chicago,... Nov 1987Two cases of Acanthamoeba keratitis and infectious crystalline keratopathy, occurring simultaneously, are presented. Three and 12 months after initiating topical...
Two cases of Acanthamoeba keratitis and infectious crystalline keratopathy, occurring simultaneously, are presented. Three and 12 months after initiating topical corticosteroid therapy in cases 1 and 2, respectively, alpha-hemolytic Streptococcus viridans was cultured from each cornea. Topical corticosteroid therapy was initiated for the treatment of an annular stromal opacity, presumably secondary to herpes simplex keratitis. Acanthamoeba was identified in culture following penetrating keratoplasty in case 1, and Acanthamoeba polyphaga, Acanthamoeba rhysodes, and Acanthamoeba castellanii were identified using indirect fluorescent antibody staining in case 2. Histopathologic examination and electron microscopy demonstrated sheets of cocci within stromal lamellae characteristic of infectious crystalline keratopathy and double-walled encysted organisms typical of Acanthamoeba. These case reports alert one to the possibility of developing bacterial keratitis, such as infectious crystalline keratopathy, following the use of topical corticosteroids for the treatment of Acanthamoeba keratitis.
Topics: Adrenal Cortex Hormones; Adult; Amebiasis; Corneal Diseases; Corneal Transplantation; Crystallization; Female; Humans; Keratitis; Male; Microscopy, Electron; Recurrence; Streptococcal Infections
PubMed: 3314824
DOI: 10.1001/archopht.1987.01060110070034 -
Iranian Journal of Parasitology 2017is an opportunistic amphizoic protozoan found in different fresh water sources. The aim of this study was to identify and characterize isolates from surface resting...
BACKGROUND
is an opportunistic amphizoic protozoan found in different fresh water sources. The aim of this study was to identify and characterize isolates from surface resting waters, in Northwest Iran.
METHODS
Samples were collected from twenty-two different areas, between May and Sep 2014. After filtration, samples were cultivated on non-nutrient agar. The extracted DNAs were amplified and sequenced using partial 18S rRNA in order to genotype and phylogenetic analyses.
RESULTS
Thirty-four (68%) out of 50 collected samples were positive for free-living amoebae based on both culture and morphological characterizations but 28 samples were identified as spp. by PCR. Sequentially, one isolate was identified as , (T5) (AN: KP940443, identity 99.7%-100%, and divergence 0.3%) whilst other sequenced isolates identified spp. (AN: KP940444-45) as very similar to and with identity 100% and divergence 0%.
CONCLUSION
Surface resting waters in Northwest Iran, were potentially contaminated with pathogenic amphizoic protozoan. Further studies will be required to determine other species and genotypes in the region.
PubMed: 28979345
DOI: No ID Found