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European Journal of Protistology Jun 2024Acanthamoeba castellanii (Douglas, 1930) Page, 1967 is the type species of a widespread genus of free-living amoebae, potentially pathogenic for humans and animals. The...
Acanthamoeba castellanii (Douglas, 1930) Page, 1967 is the type species of a widespread genus of free-living amoebae, potentially pathogenic for humans and animals. The Neff strain is one of the most widely used in biological research, serving as a model for both A. castellanii and the whole genus in general. The Neff strain, isolated in California, closely resembles another strain found in France and originally described as a separate species, Acanthamoeba terricola Pussard, 1964, but both were successively synonymized with A. castellanii. Molecular sequence analysis has largely replaced morphological diagnosis for species identification in Acanthamoeba, and rDNA phylogenies show that the Neff strain forms a distinct lineage from that of the type strain of A. castellanii. In this study, we compared the type strain of A. terricola with the Neff strain and A. castellanii, and analysed the available molecular data including new sequences obtained from A. terricola. Here we provide molecular evidence to validate the species A. terricola. The Neff strain is therefore transferred to A. terricola and should no longer be considered as belonging to A. castellanii.
Topics: Phylogeny; Acanthamoeba; DNA, Protozoan; DNA, Ribosomal; Species Specificity; Sequence Analysis, DNA; Molecular Sequence Data; Animals
PubMed: 38772052
DOI: 10.1016/j.ejop.2024.126091 -
Cornea May 2024The purpose of this study was to identify conjunctival transcriptome differences in patients with Acanthamoeba keratitis compared with keratitis with no known associated...
PURPOSE
The purpose of this study was to identify conjunctival transcriptome differences in patients with Acanthamoeba keratitis compared with keratitis with no known associated pathogen.
METHODS
The host conjunctival transcriptome of 9 patients with Acanthamoeba keratitis (AK) is compared with the host conjunctival transcriptome of 13 patients with pathogen-free keratitis. Culture and/or confocal confirmed Acanthamoeba in 8 of 9 participants with AK who underwent metagenomic RNA sequencing as the likely pathogen. Cultures were negative in all 13 cases where metagenomic RNA sequencing did not identify a pathogen.
RESULTS
Transcriptome analysis identified 36 genes differently expressed between patients with AK and patients with presumed sterile, or pathogen-free, keratitis. Gene enrichment analysis revealed that some of these genes participate in several biologic pathways important for cellular signaling, ion transport and homeostasis, glucose transport, and mitochondrial metabolism. Notable relatively differentially expressed genes with potential relevance to Acanthamoeba infection included CPS1, SLC35B4, STEAP2, ATP2B2, NMNAT3, and AKAP12.
CONCLUSIONS
This research suggests that the local transcriptome in Acanthamoeba keratitis may be sufficiently robust to be detected in the conjunctiva and that corneas infected with Acanthamoeba may be distinguished from the inflamed cornea where no pathogen was identified. Given the low sensitivity for corneal cultures, identification of differentially expressed genes may serve as a suggestive transcriptional signature allowing for a complementary diagnostic technique to identify this blinding parasite. Knowledge of differentially expressed genes may also direct investigation of disease pathophysiology and suggest novel pathways for therapeutic targets.
PubMed: 38771726
DOI: 10.1097/ICO.0000000000003545 -
Journal of Inflammation Research 2024Repeated exposure to recombinant profilin from (rAc-PF) induces allergic airway responses in vitro and in vivo. Based on the role of toll-like receptors (TLRs) in...
BACKGROUND
Repeated exposure to recombinant profilin from (rAc-PF) induces allergic airway responses in vitro and in vivo. Based on the role of toll-like receptors (TLRs) in allergic airway diseases, TLRs play a central role in innate immune responses and the adaptive immune system and regulate responses against antigens through antigen-specific receptors. In this study, we attempted to determine the molecular mechanisms underlying rAc-PF-induced allergic inflammatory responses.
METHODS
We determined the correlation between rAc-PF and TLRs and analyzed changes in allergic immune responses after blocking multiple TLR signaling under rAc-PF treatment conditions in vitro. We also compared allergic inflammatory responses in TLR2 knockout (KO) and wild-type (WT) mice. To investigate the effect of TLR2 on antigen prototyping and T cell activation in the inflammatory response induced by rAc-PF, we assessed maturation of BMDCs and polarization of naïve T cells by rAc-PF stimulation. Additionally, we compared changes in inflammation-related gene expression by rAc-PF treatment in primary lung epithelial cells isolated from TLR2 KO and WT mice.
RESULTS
The rAc-PF treatment was increased the expression level of TLR2 and 9 in vitro. But, there were not significantly differ the others TLRs expression by rAc-PF treated group. And then, the mRNA expression levels of inflammation-related genes were reduced in the TLR2 or TLR9 antagonist-treated groups compared to those in the rAc-PF alone, were no difference the treated with the other TLRs (TLR4, 6, and 7/8) antagonist. The difference was higher in the TLR2 antagonist group. Additionally, the levels of airway inflammatory disease indicators were lower in the TLR2 KO group than in the WT group after rAc-PF treatment. Furthermore, the expression of bone marrow-derived dendritic cell (BMDC) surface molecular markers following rAc-PF stimulation was lower in TLR2 KO mice than in WT mice, and TLR2 KO in BMDCs resulted in a remarkable decline in Th2/17-related cytokine production and Th2/17 subset differentiation. In addition, the expression levels of rAc-PF-induced inflammatory genes were reduced inTLR2 KO primary lung cells compared to those in normal primary lung cells.
CONCLUSION
These results suggest that the rAc-PF-induced airway inflammatory response is regulated by TLR2 signaling.
PubMed: 38764493
DOI: 10.2147/JIR.S450866 -
Frontiers in Microbiology 2024Giant viruses, categorized under are believed to exist ubiquitously in natural environments. However, comprehensive reports on isolated giant viruses remain scarce,...
Giant viruses, categorized under are believed to exist ubiquitously in natural environments. However, comprehensive reports on isolated giant viruses remain scarce, with limited information available on unrecoverable strains, viral proliferation sites, and natural hosts. Previously, the author highlighted , , and sp. styx, isolated from brackish water soil, as potential hotspots for giant virus multiplication. This study presents findings from nearly a year of monthly sampling within the same brackish water region after isolating the three aforementioned strains. This report details the recurrent isolation of a wide range of giant viruses. Each month, four soil samples were randomly collected from an approximately 5 × 10 m plot, comprising three soil samples and one water sample containing sediment from the riverbed. was used as a host for virus isolation. These efforts consistently yielded at least one viral species per month, culminating in a total of 55 giant virus isolates. The most frequently isolated species was (24 isolates), followed by (23 isolates), (6 isolates), and singular isolates of and . Notably, viruses were not consistently isolated from any of the four samples every month, with certain sites yielding no viruses. Cluster analysis based on isolate numbers revealed that soil samples from May and water and sediment samples from January produced the highest number of viral strains. These findings underscore brackish coastal soil as a significant site for isolating numerous giant viruses, highlighting the non-uniform distribution along coastlines.
PubMed: 38756730
DOI: 10.3389/fmicb.2024.1402690 -
Experimental Parasitology Jul 2024Acanthamoeba spp., are common free-living amoebae found in nature that can serve as reservoirs for certain microorganisms. The SARS-CoV-2 virus is a newly emerged...
Acanthamoeba spp., are common free-living amoebae found in nature that can serve as reservoirs for certain microorganisms. The SARS-CoV-2 virus is a newly emerged respiratory infection, and the investigation of parasitic infections remains an area of limited research. Given that Acanthamoeba can act as a host for various endosymbiotic microbial pathogens and its pathogenicity assay is not fully understood, this study aimed to identify Acanthamoeba and its bacterial and fungal endosymbionts in patients with chronic respiratory disorders and hospitalized COVID-19 patients in northern Iran. Additionally, a pathogenicity assay was conducted on Acanthamoeba isolates. Urine, nasopharyngeal swab, and respiratory specimens were collected from two groups, and each sample was cultured on 1.5% non-nutrient agar medium. The cultures were then incubated at room temperature and monitored daily for a period of two weeks. Eight Acanthamoeba isolates were identified, and PCR was performed to confirm the presence of amoebae and identify their endosymbionts. Four isolates were found to have bacterial endosymbionts, including Stenotrophomonas maltophilia and Achromobacter sp., while two isolates harbored fungal endosymbionts, including an uncultured fungus and Gloeotinia sp. In the pathogenicity assay, five isolates exhibited a higher degree of pathogenicity compared to the other three. This study provides significant insights into the comorbidity of acanthamoebiasis and COVID-19 on a global scale, and presents the first evidence of Gloeotinia sp. as a fungal endosymbiont. Nevertheless, further research is required to fully comprehend the symbiotic patterns and establish effective treatment protocols.
Topics: Humans; Iran; Acanthamoeba; COVID-19; Symbiosis; SARS-CoV-2; Male; Female; Stenotrophomonas maltophilia; Middle Aged; Adult; Amebiasis; Polymerase Chain Reaction; Aged; Vero Cells; Hospitalization; Chlorocebus aethiops
PubMed: 38754618
DOI: 10.1016/j.exppara.2024.108774 -
Frontiers in Microbiology 2024
PubMed: 38741744
DOI: 10.3389/fmicb.2024.1401217 -
MSystems Jun 2024We conducted a comprehensive comparative analysis of extracellular vesicles (EVs) from two strains, Neff (environmental) and T4 (clinical). Morphological analysis via...
We conducted a comprehensive comparative analysis of extracellular vesicles (EVs) from two strains, Neff (environmental) and T4 (clinical). Morphological analysis via transmission electron microscopy revealed slightly larger Neff EVs (average = 194.5 nm) compared to more polydisperse T4 EVs (average = 168.4 nm). Nanoparticle tracking analysis (NTA) and dynamic light scattering validated these differences. Proteomic analysis of the EVs identified 1,352 proteins, with 1,107 common, 161 exclusive in Neff, and 84 exclusively in T4 EVs. Gene ontology and Kyoto Encyclopedia of Genes and Genomes (KEGG) mapping revealed distinct molecular functions and biological processes and notably, the T4 EVs enrichment in serine proteases, aligned with its pathogenicity. Lipidomic analysis revealed a prevalence of unsaturated lipid species in Neff EVs, particularly triacylglycerols, phosphatidylethanolamines (PEs), and phosphatidylserine, while T4 EVs were enriched in diacylglycerols and diacylglyceryl trimethylhomoserine, phosphatidylcholine and less unsaturated PEs, suggesting differences in lipid metabolism and membrane permeability. Metabolomic analysis indicated Neff EVs enrichment in glycerolipid metabolism, glycolysis, and nucleotide synthesis, while T4 EVs, methionine metabolism. Furthermore, RNA-seq of EVs revealed differential transcript between the strains, with Neff EVs enriched in transcripts related to gluconeogenesis and translation, suggesting gene regulation and metabolic shift, while in the T4 EVs transcripts were associated with signal transduction and protein kinase activity, indicating rapid responses to environmental changes. In this novel study, data integration highlighted the differences in enzyme profiles, metabolic processes, and potential origins of EVs in the two strains shedding light on the diversity and complexity of EVs and having implications for understanding host-pathogen interactions and developing targeted interventions for -related diseases.IMPORTANCEA comprehensive and fully comparative analysis of extracellular vesicles (EVs) from two strains of distinct virulence, a Neff (environmental) and T4 (clinical), revealed striking differences in their morphology and protein, lipid, metabolites, and transcripts levels. Data integration highlighted the differences in enzyme profiles, metabolic processes, and potential distinct origin of EVs from both strains, shedding light on the diversity and complexity of EVs, with direct implications for understanding host-pathogen interactions, disease mechanisms, and developing new therapies for the clinical intervention of -related diseases.
Topics: Acanthamoeba castellanii; Extracellular Vesicles; Proteomics; Humans; Lipid Metabolism; Protozoan Proteins; Proteome
PubMed: 38717186
DOI: 10.1128/msystems.01226-23 -
Eye & Contact Lens Jun 2024To report first clinical use of novel medical treatment for Acanthamoeba keratitis. (Observational Study)
Observational Study
PURPOSE
To report first clinical use of novel medical treatment for Acanthamoeba keratitis.
METHODS
Interventional observational case series. Two patients with Acanthamoeba keratitis were unsuccessfully treated with polihexanide (PHMB) 0.02% and propamidine 0.1% for 6 weeks, then all were shifted in a compassionate use of PHMB 0.08% with novel standardized protocol. The postinterventional follow-up of patients was at least 7 months.
RESULTS
PHMB 0.08% eyedrops in a novel standardized protocol improved infection resolution and led to complete healing of the lesion after 4 weeks in the two cases. Corneal opacities and neovascularization decreased slowly, best-corrected visual acuity slightly improved and progressively increased in the further 7 months, and no infection recurrence occurred.
CONCLUSIONS
This preliminary report of two cases shows promising response to polihexanide 0.08% lowering drastically the illness duration, with reduced chance of recurrence, and mostly improving patients' quality of life.
Topics: Adult; Female; Humans; Male; Acanthamoeba Keratitis; Antiprotozoal Agents; Benzamidines; Biguanides; Ophthalmic Solutions; Visual Acuity; Adolescent
PubMed: 38709240
DOI: 10.1097/ICL.0000000000001092 -
Nature Communications May 2024Motion of a passive deformable object in an active environment serves as a representative of both in-vivo systems such as intracellular particle motion in Acanthamoeba...
Motion of a passive deformable object in an active environment serves as a representative of both in-vivo systems such as intracellular particle motion in Acanthamoeba castellanii, or in-vitro systems such as suspension of beads inside dense swarms of Escherichia coli. Theoretical modeling of such systems is challenging due to the requirement of well resolved hydrodynamics which can explore the spatiotemporal correlations around the suspended passive object in the active fluid. We address this critical lack of understanding using coupled hydrodynamic equations for nematic liquid crystals with finite active stress to model the active bath, and a suspended nematic droplet with zero activity. The droplet undergoes deformation fluctuations and its movement shows periods of "runs" and "stays". At relatively low interfacial tension, the droplet begins to break and mix with the outer active bath. We establish that the motion of the droplet is influenced by the interplay of spatial correlations of the flow and the size of the droplet. The mean square displacement shows a transition from ballistic to normal diffusion which depends on the droplet size. We discuss this transition in relation to spatiotemporal scales associated with velocity correlations of the active bath and the droplet.
PubMed: 38697961
DOI: 10.1038/s41467-024-47727-1 -
Investigative Ophthalmology & Visual... May 2024To investigate the adhesion of Acanthamoeba to scleral contact lens (ScCL) surface according to lens shape.
PURPOSE
To investigate the adhesion of Acanthamoeba to scleral contact lens (ScCL) surface according to lens shape.
METHODS
Two strains of A. polyphaga (CDC:V062 and ATCC 30461) and one clinical Acanthamoeba isolate, were inoculated onto five contact lens (CL): one first-generation silicone hydrogel (SHCL; lotrafilcon B; adhesion control) containing plasma surface treatment; two ScCL (fluorosilicone acrylate) one containing surface treatment composed of plasma and the other containing plasma with Hydra-PEG, and two CL designed with a flat shape having the same material and surface treatments of the ScCL. Trophozoites that adhered to the lens's surfaces were counted by inverted optical light microscopy. Possible alterations of the lens surface that could predispose amoeba adhesion and Acanthamoeba attached to these lens surfaces were evaluated by scanning electron microscopy (SEM).
RESULTS
All strains revealed greater adhesion to the ScCL when compared with the flat lenses (P < 0.001). The clinical isolate and the ATCC 30461 had a higher adhesion (P < 0.001) when compared with the CDC:V062. A rough texture was observed on the surface of the lenses that have been examined by SEM. Also, SEM revealed that the isolates had a rounded appearance on the surface of the ScCL in contrast with an elongated appearance on the surface of the silicone hydrogel.
CONCLUSIONS
The findings revealed that the curved shape of the ScCL favors amoeba adhesion.
Topics: Acanthamoeba; Microscopy, Electron, Scanning; Sclera; Humans; Contact Lenses, Hydrophilic; Cell Adhesion; Contact Lenses; Trophozoites; Hydrogels; Animals
PubMed: 38691089
DOI: 10.1167/iovs.65.5.4