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Scientific Reports Jun 2024Natural products play a significant role in providing the current demand as antiparasitic agents, which offer an attractive approach for the discovery of novel drugs....
Natural products play a significant role in providing the current demand as antiparasitic agents, which offer an attractive approach for the discovery of novel drugs. The present study aimed to evaluate in vitro the potential impact of seaweed Padina pavonica (P. pavonica) extract in combating Acanthamoeba castellanii (A. castellanii). The phytochemical constituents of the extract were characterized by Gas chromatography-mass spectrometry. Six concentrations of the algal extract were used to evaluate its antiprotozoal activity at various incubation periods. Our results showed that the extract has significant inhibition against trophozoites and cysts viability, with complete inhibition at the high concentrations. The IC of P. pavonica extract was 4.56 and 4.89 µg/mL for trophozoites and cysts, respectively, at 24 h. Morphological alterations of A. castellanii trophozoites/cysts treated with the extract were assessed using inverted and scanning electron microscopes and showed severe damage features upon treatment with the extract at different concentrations. Molecular Docking of extracted compounds against Acanthamoeba cytochrome P450 monooxygenase (AcCYP51) was performed using Autodock vina1.5.6. A pharmacokinetic study using SwissADME was also conducted to investigate the potentiality of the identified bioactive compounds from Padina extract to be orally active drug candidates. In conclusion, this study highlights the in vitro amoebicidal activity of P. pavonica extract against A. castellanii adults and cysts and suggests potential AcCYP51 inhibition.
Topics: Acanthamoeba castellanii; Molecular Docking Simulation; Acanthamoeba Keratitis; Plant Extracts; Antiprotozoal Agents; Trophozoites; Animals; Humans
PubMed: 38871751
DOI: 10.1038/s41598-024-63691-8 -
BMJ Case Reports Jun 2024Granulomatous amoebic encephalitis due to spp is a rare, near-fatal central nervous system infection. It is often seen in immunocompromised individuals. Here we...
Granulomatous amoebic encephalitis due to spp is a rare, near-fatal central nervous system infection. It is often seen in immunocompromised individuals. Here we describe a survivor of this infection who was co-infected with multidrug-resistant tuberculosis. He presented to us with features of meningitis and a history of chronic cough. The chest X-ray was classical for pulmonary tuberculosis. Neuroimaging was suggestive of encephalitis; herpes simplex virus PCR was negative. Cerebrospinal fluid (CSF) showed lymphocytic pleocytosis. Wet mounts revealed trophozoites of Currently, he is being treated with oral bedaquiline, levofloxacin, linezolid, clofazimine, cycloserine and pyridoxine for tuberculosis. He received intravenous amikacin and oral cotrimoxazole and fluconazole for infection for 1 month. The resolution was confirmed by repeating the CSF wet mount, culture and neuroimaging. He was then discharged with oral rifampicin, cotrimoxazole and fluconazole. He is currently under our close follow-up.
Topics: Humans; Male; Acanthamoeba; Tuberculosis, Meningeal; Amebiasis; Tuberculosis, Multidrug-Resistant; Immunocompetence; Coinfection
PubMed: 38871639
DOI: 10.1136/bcr-2024-260613 -
Parasitology Research Jun 2024Managing primary amoebic meningoencephalitis, induced by Naegleria fowleri poses a complex medical challenge. There is currently no specific anti-amoebic drug that has...
Managing primary amoebic meningoencephalitis, induced by Naegleria fowleri poses a complex medical challenge. There is currently no specific anti-amoebic drug that has proven effectiveness against N. fowleri infection. Ongoing research endeavours are dedicated to uncovering innovative treatment strategies, including the utilization of drugs and immune modulators targeting Naegleria infection. In this study, we explored the potential of imidazo[2,1-b]thiazole and imidazooxazole derivatives that incorporate sulfonate and sulfamate groups as agents with anti-amoebic properties against N. fowleri. We assessed several synthesized compounds (1f, 1m, 1q, 1s, and 1t) for their efficacy in eliminating amoebae, their impact on cytotoxicity, and their influence on the damage caused to human cerebral microvascular endothelial (HBEC-5i) cells when exposed to the N. fowleri (ATCC 30174) strain. The outcomes revealed that, among the five compounds under examination, 1m, 1q, and 1t demonstrated notable anti-parasitic effects against N. fowleri (P ≤ 0.05). Compound 1t exhibited the highest anti-parasitic activity, reducing N. fowleri population by 80%. Additionally, three compounds, 1m, 1q, and 1t, significantly mitigated the damage inflicted on host cells by N. fowleri. However, the results of cytotoxicity analysis indicated that while 1m and 1q had minimal cytotoxic effects on endothelial cells, compound 1t caused moderate cytotoxicity (34%). Consequently, we conclude that imidazo[2,1-b]thiazole and imidazooxazole derivatives containing sulfonate and sulfamate groups exhibit a marked capacity to eliminate amoebae viability while causing limited toxicity to human cells. In aggregate, these findings hold promise that could potentially evolve into novel therapeutic options for treating N. fowleri infection.
Topics: Humans; Thiazoles; Naegleria fowleri; Endothelial Cells; Antiprotozoal Agents; Cell Line; Imidazoles; Oxazoles; Cell Survival
PubMed: 38864931
DOI: 10.1007/s00436-024-08255-5 -
Frontiers in Cellular and Infection... 2024Acanthamoeba infection is a serious public health concern, necessitating the development of effective and safe anti-Acanthamoeba chemotherapies. Poly (ADP-ribose)...
INTRODUCTION
Acanthamoeba infection is a serious public health concern, necessitating the development of effective and safe anti-Acanthamoeba chemotherapies. Poly (ADP-ribose) polymerases (PARPs) govern a colossal amount of biological processes, such as DNA damage repair, protein degradation and apoptosis. Multiple PARP-targeted compounds have been approved for cancer treatment. However, repurposing of PARP inhibitors to treat Acanthamoeba is poorly understood.
METHODS
In the present study, we attempted to fill these knowledge gaps by performing anti-Acanthamoeba efficacy assays, cell biology experiments, bioinformatics, and transcriptomic analyses.
RESULTS
Using a homology model of Acanthamoeba poly (ADP-ribose) polymerases (PARPs), molecular docking of approved drugs revealed three potential inhibitory compounds: olaparib, venadaparib and AZ9482. In particular, venadaparib exhibited superior docking scores (-13.71) and favorable predicted binding free energy (-89.28 kcal/mol), followed by AZ9482, which showed a docking score of -13.20 and a binding free energy of -92.13 kcal/mol. Notably, the positively charged cyclopropylamine in venadaparib established a salt bridge (through E535) and a hydrogen bond (via N531) within the binding pocket. For comparison, AZ9482 was well stacked by the surrounding aromatic residues including H625, Y652, Y659 and Y670. In an assessment of trophozoites viability, AZ9482 exhibited a dose-and time-dependent anti-trophozoite effect by suppressing Acanthamoeba PARP activity, unlike olaparib and venadaparib. An Annexin V-fluorescein isothiocyanate/propidium iodide apoptosis assay revealed AZ9482 induced trophozoite necrotic cell death rather than apoptosis. Transcriptomics analyses conducted on Acanthamoeba trophozoites treated with AZ9482 demonstrated an atlas of differentially regulated proteins and genes, and found that AZ9482 rapidly upregulates a multitude of DNA damage repair pathways in trophozoites, and intriguingly downregulates several virulent genes. Analyzing gene expression related to DNA damage repair pathway and the rate of apurinic/apyrimidinic (AP) sites indicated DNA damage efficacy and repair modulation in Acanthamoeba trophozoites following AZ9482 treatment.
DISCUSSION
Collectively, these findings highlight AZ9482, as a structurally unique PARP inhibitor, provides a promising prototype for advancing anti-Acanthamoeba drug research.
Topics: Molecular Docking Simulation; Poly(ADP-ribose) Polymerase Inhibitors; Humans; Piperazines; Phthalazines; Drug Repositioning; Poly(ADP-ribose) Polymerases; Acanthamoeba; Computational Biology; Apoptosis; Gene Expression Profiling; Antiprotozoal Agents; Trophozoites
PubMed: 38863831
DOI: 10.3389/fcimb.2024.1414135 -
Frontiers in Cellular and Infection... 2024Pathogenic and free-living are widely distributed in the environment and have been reported to cause keratitis and universally fatal encephalitis. Primary cutaneous...
Pathogenic and free-living are widely distributed in the environment and have been reported to cause keratitis and universally fatal encephalitis. Primary cutaneous acanthamoebiasis caused by is exceedingly rare and presents as isolated necrotic cutaneous lesions without involvement of the cornea or central nervous system. Cutaneous acanthamoebiasis often occurs in immunocompromised patients and is likely overlooked or even misdiagnosed only by cutaneous biopsy tissue histopathological analysis. Here, we report a HIV-infected 63-year-old female with oral leukoplakia for 4 months and scattered large skin ulcers all over the body for 2 months. The cause of the cutaneous lesions was unclear through cutaneous specimens histopathological analysis, and subsequently were detected by metagenomic next-generation sequencing (mNGS), which may be the cause of cutaneous lesions. Based on the mNGS results, a pathologist subsequently reviewed the previous pathological slides and found trophozoites of so that the cause was identified, and the skin ulcers improved significantly after treatment with multi-drug combination therapy. is also a host of pathogenic microorganisms. The presence of endosymbionts enhances the pathogenicity of , and no other pathogens were reported in this case. mNGS is helpful for rapidly diagnosing the etiology of rare skin diseases and can indicate the presence or absence of commensal microorganisms.
Topics: Humans; Female; High-Throughput Nucleotide Sequencing; Amebiasis; Metagenomics; Middle Aged; Acanthamoeba; HIV Infections; Skin; Treatment Outcome
PubMed: 38863830
DOI: 10.3389/fcimb.2024.1356095 -
Virology Journal Jun 2024The discovery of mimivirus in 2003 prompted the search for novel giant viruses worldwide. Despite increasing interest, the diversity and distribution of giant viruses is...
The discovery of mimivirus in 2003 prompted the search for novel giant viruses worldwide. Despite increasing interest, the diversity and distribution of giant viruses is barely known. Here, we present data from a 2012-2022 study aimed at prospecting for amoebal viruses in water, soil, mud, and sewage samples across Brazilian biomes, using Acanthamoeba castellanii for isolation. A total of 881 aliquots from 187 samples covering terrestrial and marine Brazilian biomes were processed. Electron microscopy and PCR were used to identify the obtained isolates. Sixty-seven amoebal viruses were isolated, including mimiviruses, marseilleviruses, pandoraviruses, cedratviruses, and yaraviruses. Viruses were isolated from all tested sample types and almost all biomes. In comparison to other similar studies, our work isolated a substantial number of Marseillevirus and cedratvirus representatives. Taken together, our results used a combination of isolation techniques with microscopy, PCR, and sequencing and put highlight on richness of giant virus present in different terrestrial and marine Brazilian biomes.
Topics: Brazil; Giant Viruses; Phylogeny; Polymerase Chain Reaction; Acanthamoeba castellanii; Soil Microbiology; Sewage; Sequence Analysis, DNA; Seawater; Water Microbiology
PubMed: 38858684
DOI: 10.1186/s12985-024-02404-z -
The ISME Journal Jan 2024Amoeba-bacteria interactions are prevalent in both natural ecosystems and engineered environments. Amoebae, as essential consumers, hold significant ecological...
Amoeba-bacteria interactions are prevalent in both natural ecosystems and engineered environments. Amoebae, as essential consumers, hold significant ecological importance within ecosystems. Besides, they can establish stable symbiotic associations with bacteria. Copper plays a critical role in amoeba predation by either killing or restricting the growth of ingested bacteria in phagosomes. However, certain symbiotic bacteria have evolved mechanisms to persist within the phagosomal vacuole, evading antimicrobial defenses. Despite these insights, the impact of copper on the symbiotic relationships between amoebae and bacteria remains poorly understood. In this study, we investigated the effects of copper stress on amoebae and their symbiotic relationships with bacteria. Our findings revealed that elevated copper concentration adversely affected amoeba growth and altered cellular fate. Symbiont type significantly influenced the responses of the symbiotic relationships to copper stress. Beneficial symbionts maintained stability under copper stress, but parasitic symbionts exhibited enhanced colonization of amoebae. Furthermore, copper stress favored the transition of symbiotic relationships between amoebae and beneficial symbionts toward the host's benefit. Conversely, the pathogenic effects of parasitic symbionts on hosts were exacerbated under copper stress. This study sheds light on the intricate response mechanisms of soil amoebae and amoeba-bacteria symbiotic systems to copper stress, providing new insights into symbiotic dynamics under abiotic factors. Additionally, the results underscore the potential risks of copper accumulation in the environment for pathogen transmission and biosafety.
Topics: Copper; Symbiosis; Amoeba; Bacteria; Stress, Physiological; Bacterial Physiological Phenomena
PubMed: 38848278
DOI: 10.1093/ismejo/wrae100 -
Food Microbiology Sep 2024Acanthamoeba spp., are ubiquitous protist which belongs to Free-Living Amoeba (FLA) group, is considered as causal agent of side-threatening keratitis or fatal...
Acanthamoeba spp., are ubiquitous protist which belongs to Free-Living Amoeba (FLA) group, is considered as causal agent of side-threatening keratitis or fatal encephalitis among other human infections. Besides, this parasite has been reported as host for other microorganisms important to human health such as Campylobacter spp. or Vibrio spp. among others. This role of Acanthamoeba as pathogen and environmental phagocyte has increased the reports confirming its presence in human related environments, acting as a water quality indicator. Considering the tide relationship between water and kitchen environments, and the high prevalence of Acanthamoeba in water sources, the present study aims to establish a quick and accurate protocol based on DNA extraction and a real time qPCR assay to detect Acanthamoeba spp. in dishcloths. The procedure has been validated by processing 17 used dishcloths. Our findings demonstrated the high sensitivity of the qPCR assay used which was capable of detecting up to one Acanthamoeba from an in vitro contaminated dishcloth. The protocol accurately detected 64.7% of positive samples for Acanthamoeba spp, (in 4 samples DNA concentrations corresponded to 1-10 amoebae). Our findings demonstrate the importance of FLA surveillance by efficient and sensitive methods since one amoeba is capable of colonizing human related food environments such as kitchens sinks and could be a potential source of infection.
Topics: Acanthamoeba; Real-Time Polymerase Chain Reaction; DNA, Protozoan; Humans; Sensitivity and Specificity
PubMed: 38839225
DOI: 10.1016/j.fm.2024.104562 -
Veterinary Parasitology Jul 2024Blastocystis inhabits the digestive tracts of a diverse range of hosts. Transmission patterns, including host specificity, and the clinical and public health...
Blastocystis inhabits the digestive tracts of a diverse range of hosts. Transmission patterns, including host specificity, and the clinical and public health significance of Blastocystis in humans remain poorly understood. This study aimed to investigate the distribution and genetic diversity of Blastocystis in herbivorous and carnivorous reptiles in Eastern Thailand. A total of 501 faecal samples were collected from 363 iguanas, 79 bearded dragons, 50 tortoises, and nine snakes in an animal breeding farm in Chonburi Province, Eastern Thailand. Detection and differentiation of Blastocystis was based on amplification, sequencing, and phylogenetic analysis of specific small subunit (SSU) ribosomal RNA genes from faecal DNA extracted from the samples. Altogether 101/501 samples (20 %) were polymerase chain reaction (PCR) and sequencing-positive for Blastocystis, 90 (89 %) of which were from iguanas; the remaining positive samples were from African spurred tortoise (n=6), Bearded dragon (n=3), Leopard tortoise (n=1), and Red-footed tortoise (n=1). Phylogenetic analysis revealed that most of the Blastocystis sequences from iguanas were largely similar, and they were distinct from those of the tortoises. Subtype 17 was found in the three bearded dragons and likely reflected Blastocystis from prey animals. This is the largest survey of Blastocystis in reptiles to date. Remarkable differences in Blastocystis colonization rates and genetic diversity were observed between iguanas and other reptile orders, and what was considered Blastocystis colonization was only observed in herbivorous reptiles.
Topics: Animals; Blastocystis; Thailand; Genetic Variation; Blastocystis Infections; Host Specificity; Phylogeny; Feces; Reptiles; Turtles; Lizards; Snakes
PubMed: 38838380
DOI: 10.1016/j.vetpar.2024.110218 -
Parasites, Hosts and Diseases May 2024Free-living amoebae (FLA) are found in diverse environments, such as soils, rivers, and seas. Hence, they can be used as bioindicators to assess the water quality based...
Free-living amoebae (FLA) are found in diverse environments, such as soils, rivers, and seas. Hence, they can be used as bioindicators to assess the water quality based solely on their presence. In this study, we determined the presence of FLA in river water by filtering water samples collected from various sites and culturing the resulting filtrates. FLA were detected in all the water samples with varying quality grades (Grades Ι-V). The significant increase in the size of the amoebae population with the deterioration in the water quality. Monoxenic cultures of the amoebae were performed, and genomic DNAs were isolated, among which 18S rDNAs were sequenced to identify the amoeba species. Of the 12 species identified, 10 belonged to the Acanthamoeba genus; of the remaining 2 species, one was identified as Vannella croatica and the other as a species of Vermamoeba. Acanthamoeba was detected in samples with Grades Ι to VI quality, whereas the Vermamoeba species was present only in Grade Ι water. V. croatica was found exclusively in water with Grade ΙΙ quality. Following morphological observations, genomic DNA was sequenced using 16S rDNA to determine whether the species of Acanthamoeba harbored endosymbionts. Most of the isolated Acanthamoeba contained endosymbionts, among which 4 species of endogenous bacteria were identified and examined using transmission electron microscopy. This study provides evidence that the distribution of amoebae other than Acanthamoeba may be associated with water quality. However, further confirmation will be required based on accurate water quality ratings and assessments using a more diverse range of FLA.
Topics: Amoeba; Water Quality; Phylogeny; Rivers; DNA, Protozoan; Acanthamoeba; RNA, Ribosomal, 18S; DNA, Ribosomal; Biodiversity; Sequence Analysis, DNA; RNA, Ribosomal, 16S
PubMed: 38835259
DOI: 10.3347/PHD.24020