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Botwright NA, Rusu A, English CJ, Hutt O, Wynne JW. A High Throughput Viability Screening Method for the Marine Ectoparasite Neoparamoeba perurans. Protist 2020; 171:125773. [DOI: 10.1016/j.protis.2020.125773] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 10/15/2020] [Accepted: 10/29/2020] [Indexed: 11/26/2022]
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Bínová E, Bína D, Nohýnková E. DNA content in Acanthamoeba during two stress defense reactions: Encystation, pseudocyst formation and cell cycle. Eur J Protistol 2020; 77:125745. [PMID: 33218872 DOI: 10.1016/j.ejop.2020.125745] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Revised: 08/22/2020] [Accepted: 10/19/2020] [Indexed: 12/01/2022]
Abstract
During environmental stress, the vegetative cells of the facultative pathogenic amoeba Acanthamoeba castellanii reversibly differentiate into resistant dormant stages, namely, cysts or pseudocysts. The type of resistant stage depends on the nature and duration of the stressor. Cell differentiation is accompanied by changes in morphology and cellular metabolism. Moreover, cell differentiation is also expected to be closely linked to the regulation of the cell cycle and, thus, to cellular DNA content. While the existence of the resistant stages in A. castellanii is well known, there is no consensus regarding the relationship between differentiation and cell cycle progression. In the present work, we used flow cytometry analysis to explore the changes in the DNA content during Acanthamoeba encystation and pseudocyst formation. Our results strongly indicate that A. castellanii enters encystation from the G2 phase of the cell cycle. In contrast, differentiation into pseudocysts can begin in the G1 and G2 phases. In addition, we present a phylogenetic analysis and classification of the main cell cycle regulators, namely, cyclin-dependent kinases and cyclins that are found in the genome of A. castellanii.
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Affiliation(s)
- Eva Bínová
- Institute of Immunology and Microbiology, First Faculty of Medicine, Charles University, Studnickova 7, 128 00 Prague 2, Czech Republic
| | - David Bína
- Faculty of Science, University of South Bohemia, Branišovská 1760 and The Czech Academy of Sciences, Biology Centre, Branišovská 31, 370 05 České Budějovice, Czech Republic
| | - Eva Nohýnková
- Institute of Immunology and Microbiology, First Faculty of Medicine, Charles University, Studnickova 7, 128 00 Prague 2, Czech Republic.
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Dickson A, Cooper E, Fakae LB, Wang B, Chan KLA, Elsheikha HM. In Vitro Growth- and Encystation-Inhibitory Efficacies of Matcha Green Tea and Epigallocatechin Gallate Against Acanthameoba Castellanii. Pathogens 2020; 9:pathogens9090763. [PMID: 32957663 PMCID: PMC7558711 DOI: 10.3390/pathogens9090763] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Revised: 08/31/2020] [Accepted: 09/09/2020] [Indexed: 11/25/2022] Open
Abstract
We examined the inhibitory effect of matcha green tea (Camellia sinensis) and epigallocatechin gallate (EGCg; the most abundant catechin in tea) on the vegetative growth and encystation of Acanthamoeba castellanii T4 genotype. The sulforhodamine B (SRB) stain-based colorimetric assay and hemocytometer counting were used to determine the reduction in A. castellanii trophozoite proliferation and encystation, in response to treatment with C. sinensis or EGCg. Fourier transform infrared (FTIR) microscopy was used to analyze chemical changes in the trophozoites and cysts due to C. sinensis treatment. Hot brewed and cold brewed matcha inhibited the growth of trophozoites by >40% at a 100 % concentration. EGCg at concentrations of 50 to 500 µM significantly inhibited the trophozoite growth compared to control. Hot brewed matcha (100% concentration) also showed an 87% reduction in the rate of encystation compared to untreated control. Although 500 µM of EGCg increased the rate of encystation by 36.3%, 1000 µM reduced it by 27.7%. Both percentages were not significant compared to control. C. sinensis induced more cytotoxicity to Madin Darby canine kidney cells compared to EGCg. FTIR chemical fingerprinting analysis showed that treatment with brewed matcha significantly increased the levels of glycogen and carbohydrate in trophozoites and cysts.
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Affiliation(s)
- Ameliya Dickson
- School of Veterinary Medicine and Science, Faculty of Medicine and Health Sciences, University of Nottingham, Loughborough LE12 5RD, UK; (A.D.); (E.C.); (L.B.F.)
| | - Elise Cooper
- School of Veterinary Medicine and Science, Faculty of Medicine and Health Sciences, University of Nottingham, Loughborough LE12 5RD, UK; (A.D.); (E.C.); (L.B.F.)
| | - Lenu B. Fakae
- School of Veterinary Medicine and Science, Faculty of Medicine and Health Sciences, University of Nottingham, Loughborough LE12 5RD, UK; (A.D.); (E.C.); (L.B.F.)
| | - Bo Wang
- School of Mathematics and Actuarial Science, University of Leicester, Leicester LE1 7RH, UK;
| | - Ka Lung Andrew Chan
- Institute of Pharmaceutical Science, King’s College London, London SE1 9NH, UK;
| | - Hany M. Elsheikha
- School of Veterinary Medicine and Science, Faculty of Medicine and Health Sciences, University of Nottingham, Loughborough LE12 5RD, UK; (A.D.); (E.C.); (L.B.F.)
- Correspondence: ; Tel.: +44-0115-951-6445
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Fakae LB, Stevenson CW, Zhu XQ, Elsheikha HM. In vitro activity of Camellia sinensis (green tea) against trophozoites and cysts of Acanthamoeba castellanii. Int J Parasitol Drugs Drug Resist 2020; 13:59-72. [PMID: 32512260 PMCID: PMC7281304 DOI: 10.1016/j.ijpddr.2020.05.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Revised: 05/06/2020] [Accepted: 05/12/2020] [Indexed: 01/06/2023]
Abstract
The effect of Camellia sinensis (green tea) on the growth of Acanthamoeba castellanii trophozoites was examined using a microplate based-Sulforhodamine B (SRB) assay. C. sinensis hot and cold brews at 75% and 100% concentrations significantly inhibited the growth of trophozoites. We also examined the structural alterations in C. sinensis-treated trophozoites using transmission electron microscopy (TEM) and scanning electron microscopy (SEM). This analysis showed that C. sinensis compromised the cell membrane integrity and caused progressive destruction of trophozoites. C. sinensis also significantly inhibited the parasite's ability to form cysts in a dose-dependent manner and reduced the rate of excystation from cysts to trophozoites. C. sinensis exhibited low cytotoxic effects on primary corneal stromal cells. However, cytotoxicity was more pronounced in SV40-immortalized corneal epithelial cells. Chromatographic analysis showed that both hot and cold C. sinensis brews contained the same number and type of chemical compounds. This work demonstrated that C. sinensis has anti-acanthamoebic activity against trophozoite and cystic forms of A. castellanii. Further studies are warranted to identify the exact substances in C. sinensis that have the most potent anti-acanthamoebic effect.
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Affiliation(s)
- Lenu B Fakae
- School of Veterinary Medicine and Science, University of Nottingham, Sutton Bonington Campus, Loughborough, LE12 5RD, UK; School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, LE12 5RD, UK; Rivers State University, Nkpolu - Oroworukwo P.M.B 5080, Port Harcourt, Rivers State, Nigeria
| | - Carl W Stevenson
- School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, LE12 5RD, UK
| | - Xing-Quan Zhu
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, 730046, China
| | - Hany M Elsheikha
- School of Veterinary Medicine and Science, University of Nottingham, Sutton Bonington Campus, Loughborough, LE12 5RD, UK.
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Juárez MM, Tártara LI, Cid AG, Real JP, Bermúdez JM, Rajal VB, Palma SD. Acanthamoeba in the eye, can the parasite hide even more? Latest developments on the disease. Cont Lens Anterior Eye 2017; 41:245-251. [PMID: 29273391 DOI: 10.1016/j.clae.2017.12.017] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Revised: 12/12/2017] [Accepted: 12/13/2017] [Indexed: 12/01/2022]
Abstract
Acanthamoeba spp. is a free living protozoan in the environment, but can cause serious diseases. Acanthamoeba keratitis (AK), a severe and painful eye infection, must be treated as soon as possible to prevent ulceration of the cornea, loss of visual acuity, and eventually blindness or enucleation. Although the disease affects principally contact lens (CLs) wearers, it is recognized nowadays as a cause of keratitis also in non-CLs wearers. Although the number of infections caused by these amoebae is low, AK is an emerging disease presenting an extended number of cases each year worldwide mostly due to the increasing use of CLs, but also to better diagnostic methods and awareness. There are two principal causes that lead to severe outcomes: misdiagnosis or late diagnosis of the causal agent, and lack of a fully effective therapy due to the existence of a highly resistant cyst stage of Acanthamoeba. Recent studies have reported different genotypes that have not been previously associated with this disease. In addition, Acanthamoeba can act as a reservoir for phylogenetically diverse microorganisms. In this regard, recently giant viruses called Pandoravirus have been found within genotypes producing keratitis. What potential risk this poses is not yet known. This review focuses on an overview of the present status and future prospects of this re-emerging pathology, including features of the parasite, epidemiology, clinical aspects, diagnosis, and treatment.
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Affiliation(s)
- M M Juárez
- Instituto de Investigaciones para la Industria Química (INIQUI, CONICET - Universidad Nacional de Salta), Av. Bolivia 5150, 4400, Salta, Argentina; Facultad de Ingeniería, Universidad Nacional de Salta, Av. Bolivia 5150, 4400, Salta, Argentina; Facultad de Ciencias de la Salud, Universidad Nacional de Salta, Av. Bolivia 5150, 4400, Salta, Argentina
| | - L I Tártara
- Unidad de Investigación y Desarrollo en Tecnología Farmacéutica (UNITEFA, CONICET - Departamento de Ciencias Farmacéuticas, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba), Ciudad Universitaria, 5000, Córdoba, Argentina
| | - A G Cid
- Instituto de Investigaciones para la Industria Química (INIQUI, CONICET - Universidad Nacional de Salta), Av. Bolivia 5150, 4400, Salta, Argentina; Facultad de Ingeniería, Universidad Nacional de Salta, Av. Bolivia 5150, 4400, Salta, Argentina
| | - J P Real
- Unidad de Investigación y Desarrollo en Tecnología Farmacéutica (UNITEFA, CONICET - Departamento de Ciencias Farmacéuticas, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba), Ciudad Universitaria, 5000, Córdoba, Argentina
| | - J M Bermúdez
- Instituto de Investigaciones para la Industria Química (INIQUI, CONICET - Universidad Nacional de Salta), Av. Bolivia 5150, 4400, Salta, Argentina; Facultad de Ingeniería, Universidad Nacional de Salta, Av. Bolivia 5150, 4400, Salta, Argentina
| | - V B Rajal
- Instituto de Investigaciones para la Industria Química (INIQUI, CONICET - Universidad Nacional de Salta), Av. Bolivia 5150, 4400, Salta, Argentina; Facultad de Ingeniería, Universidad Nacional de Salta, Av. Bolivia 5150, 4400, Salta, Argentina; Singapore Centre on Environmental Life Sciences Engineering (SCELSE), School of Biological Sciences, Nanyang Technological University, Singapore
| | - S D Palma
- Unidad de Investigación y Desarrollo en Tecnología Farmacéutica (UNITEFA, CONICET - Departamento de Ciencias Farmacéuticas, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba), Ciudad Universitaria, 5000, Córdoba, Argentina.
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Bínová E, Bína D, Ashford DA, Thomas-Oates J, Nohýnková E. Trehalose During Two Stress Responses in Acanthamoeba : Differentiation Between Encystation and Pseudocyst Formation. Protist 2017; 168:649-662. [DOI: 10.1016/j.protis.2017.09.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Revised: 08/08/2017] [Accepted: 09/07/2017] [Indexed: 01/05/2023]
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Luna-Nácar M, Navarrete-Perea J, Moguel B, Bobes RJ, Laclette JP, Carrero JC. Proteomic Study of Entamoeba histolytica Trophozoites, Cysts, and Cyst-Like Structures. PLoS One 2016; 11:e0156018. [PMID: 27228164 PMCID: PMC4882050 DOI: 10.1371/journal.pone.0156018] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Accepted: 05/09/2016] [Indexed: 11/23/2022] Open
Abstract
The cyst stage of Entamoeba histolytica is a promising therapeutic target against human amoebiasis. Our research team previously reported the production in vitro of Cyst-Like Structures (CLS) sharing structural features with cysts, including rounded shape, size reduction, multinucleation, and the formation of a chitin wall coupled to the overexpression of glucosamine 6-phosphate isomerase, the rate-limiting enzyme of the chitin synthesis pathway. A proteomic study of E. histolytica trophozoites, cysts, and in vitro-produced CLS is reported herein to determine the nature of CLS, widen our knowledge on the cyst stage, and identify possible proteins and pathways involved in the encystment process. Total protein extracts were obtained from E. histolytica trophozoites, CLS, and partially purified cysts recovered from the feces of amoebic human patients; extracts were trypsin-digested and analyzed by LC-MS/MS. In total, 1029 proteins were identified in trophozoites, 550 in CLS, and 411 in cysts, with 539, 299, and 84 proteins unique to each sample, respectively, and only 74 proteins shared by all three stages. About 70% of CLS proteins were shared with trophozoites, even though differences were observed in the relative protein abundance. While trophozoites showed a greater abundance of proteins associated to a metabolically active cell, CLS showed higher expression of proteins related to proteolysis, redox homeostasis, and stress response. In addition, the expression of genes encoding for the cyst wall proteins Jessie and Jacob was detected by RT-PCR and the Jacob protein identified by Western blotting and immunofluorescence in CLS. However, the proteomic profile of cysts as determined by LC-MS/MS was very dissimilar to that of trophozoites and CLS, with almost 40% of hypothetical proteins. Our global results suggest that CLS are more alike to trophozoites than to cysts, and they could be generated as a rapid survival response of trophozoites to a stressful condition, which allows the parasite to survive temporarily inside a chitin-like resistant cover containing Jacob protein. Our findings lead us to suggest that encystment and CLS formation could be distinct stress responses. In addition, we show that cysts express a high number of genes with unknown function, including four new, highly antigenic, possibly membrane-located proteins that could be targets of therapeutic and diagnostic usefulness.
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Affiliation(s)
- Milka Luna-Nácar
- Department of Immunology, Instituto de Investigaciones Biomédicas, Tercer Circuito Exterior s/n, Ciudad Universitaria, Universidad Nacional Autónoma de México, 04510, México D.F., México
| | - José Navarrete-Perea
- Department of Immunology, Instituto de Investigaciones Biomédicas, Tercer Circuito Exterior s/n, Ciudad Universitaria, Universidad Nacional Autónoma de México, 04510, México D.F., México
| | - Bárbara Moguel
- Department of Immunology, Instituto de Investigaciones Biomédicas, Tercer Circuito Exterior s/n, Ciudad Universitaria, Universidad Nacional Autónoma de México, 04510, México D.F., México
| | - Raúl J. Bobes
- Department of Immunology, Instituto de Investigaciones Biomédicas, Tercer Circuito Exterior s/n, Ciudad Universitaria, Universidad Nacional Autónoma de México, 04510, México D.F., México
| | - Juan P. Laclette
- Department of Immunology, Instituto de Investigaciones Biomédicas, Tercer Circuito Exterior s/n, Ciudad Universitaria, Universidad Nacional Autónoma de México, 04510, México D.F., México
| | - Julio C. Carrero
- Department of Immunology, Instituto de Investigaciones Biomédicas, Tercer Circuito Exterior s/n, Ciudad Universitaria, Universidad Nacional Autónoma de México, 04510, México D.F., México
- * E-mail:
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Carnt N, Stapleton F. Strategies for the prevention of contact lens-relatedAcanthamoebakeratitis: a review. Ophthalmic Physiol Opt 2015; 36:77-92. [DOI: 10.1111/opo.12271] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Accepted: 11/23/2015] [Indexed: 11/28/2022]
Affiliation(s)
- Nicole Carnt
- Save Sight Institute; University of Sydney; Sydney Australia
- School of Optometry and Vision Science; University of New South Wales; Sydney Australia
| | - Fiona Stapleton
- School of Optometry and Vision Science; University of New South Wales; Sydney Australia
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Kovacs CJ, Lynch SC, Rah MJ, Millard KA, Morris TW. Acanthamoeba encystment: multifactorial effects of buffers, biocides, and demulcents present in contact lens care solutions. Clin Ophthalmol 2015; 9:1905-13. [PMID: 26508829 PMCID: PMC4610783 DOI: 10.2147/opth.s88199] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose To determine whether agents which are purportedly capable of inducing encystment of Acanthamoeba can recapitulate the signal when tested in differing formulations. Methods In accordance with the International Standard ISO 19045, Acanthamoeba castellanii ATCC 50370 trophozoites were cultured in antibiotic-free axenic medium, treated with test solutions, and encystment rates plus viability were measured via bright field and fluorescent microscopy. Test solutions included phosphate-buffered saline (PBS), borate-buffered saline, biguanide- and hydrogen peroxide (H2O2)-based biocides, propylene glycol (PG) and povidone (POV) ophthalmic demulcents, and one-step H2O2-based contact lens disinfection systems. Results Only PBS solutions with 0.25 ppm polyaminopropyl biguanide (PAPB) and increasing concentrations of PG and POV stimulated A. castellanii encystment in a dose-dependent manner, whereas PBS solutions containing 3% H2O2 and increasing concentrations of PG and POV did not stimulate encystment. Borate-buffered saline and PBS/citrate solutions containing PG also did not stimulate encystment. In addition, no encystment was observed after 24 hours, 7 days, or 14 days of exposures of trophozoites to one-step H2O2 contact lens disinfection products or related solutions. Conclusion The lack of any encystment observed when trophozoites were treated with existing or new one-step H2O2 contact lens care products, as well as when trophozoites were exposed to various related test solutions, confirms that Acanthamoeba encystment is a complex process which depends upon simultaneous contributions of multiple factors including buffers, biocides, and demulcents.
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Statins and voriconazole induce programmed cell death in Acanthamoeba castellanii. Antimicrob Agents Chemother 2015; 59:2817-24. [PMID: 25733513 DOI: 10.1128/aac.00066-15] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Accepted: 02/25/2015] [Indexed: 12/11/2022] Open
Abstract
Members of the genus Acanthamoeba are facultative pathogens of humans, causing a sight-threatening keratitis and a life-threatening encephalitis. In order to treat those infections properly, it is necessary to target the treatment not only to the trophozoite but also to the cyst. Furthermore, it may be advantageous to avoid parasite killing by necrosis, which may induce local inflammation. We must also avoid toxicity of host tissue. Many drugs which target eukaryotes are known to induce programmed cell death (PCD), but this process is poorly characterized in Acanthamoeba. Here, we study the processes of programmed cell death in Acanthamoeba, induced by several drugs, such as statins and voriconazole. We tested atorvastatin, fluvastatin, simvastatin, and voriconazole at the 50% inhibitory concentrations (IC50s) and IC90s that we have previously established. In order to evaluate this phenomenon, we investigated the DNA fragmentation, one of the main characteristics of PCD, with quantitative and qualitative techniques. Also, the changes related to phosphatidylserine exposure on the external cell membrane and cell permeability were studied. Finally, because caspases are key to PCD pathways, caspase activity was evaluated in Acanthamoeba. All the drugs assayed in this study induced PCD in Acanthamoeba. To the best of our knowledge, this is the first study where PCD induced by drugs is described quantitatively and qualitatively in Acanthamoeba.
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Stress management in cyst-forming free-living protists: programmed cell death and/or encystment. BIOMED RESEARCH INTERNATIONAL 2015; 2015:437534. [PMID: 25648302 PMCID: PMC4306356 DOI: 10.1155/2015/437534] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Revised: 12/08/2014] [Accepted: 12/24/2014] [Indexed: 11/21/2022]
Abstract
In the face of harsh conditions and given a choice, a cell may (i) undergo programmed cell death, (ii) transform into a cancer cell, or (iii) enclose itself into a cyst form. In metazoans, the available evidence suggests that cellular machinery exists only to execute or avoid programmed cell death, while the ability to form a cyst was either lost or never developed. For cyst-forming free-living protists, here we pose the question whether the ability to encyst was gained at the expense of the programmed cell death or both functions coexist to counter unfavorable environmental conditions with mutually exclusive phenotypes.
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Lloyd D. Encystment in Acanthamoeba castellanii: a review. Exp Parasitol 2014; 145 Suppl:S20-7. [PMID: 24726698 DOI: 10.1016/j.exppara.2014.03.026] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2013] [Revised: 03/02/2014] [Accepted: 03/04/2014] [Indexed: 10/25/2022]
Abstract
Differentiation of Acanthamoeba castellanii trophozoites involves massive turnover of cellular components and remodelling of organelle structure and function so as to produce a cryptobiotic cell, resistant to desiccation, heat, freezing, and chemical treatments. This review presents a summary of a decade of research on the most studied aspects of the biochemistry of this process, with emphasis on problems of biocide and drug resistances, putative new targets, molecular and cell biology of the process of encystment, and the characteristics of the encysted state. As well as the intrinsic pathogenicity of the organism towards the cornea, and the ability of related species to invade the human brain, its propensity for harbouring and transmitting pathogenic bacteria and viruses is considerable and leads to increasing concerns. The long-term survival and resistance of cysts to drugs and biocides adds another layer of complexity to the problem of their elimination.
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Affiliation(s)
- David Lloyd
- School of Biosciences, Cardiff University, Cardiff, Wales CF10 3AT, UK.
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Evaluation of Acanthamoeba myosin-IC as a potential therapeutic target. Antimicrob Agents Chemother 2014; 58:2150-5. [PMID: 24468784 DOI: 10.1128/aac.01199-13] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Members of the genus Acanthamoeba are facultative pathogens of humans, causing a sight-threatening keratitis and a fatal encephalitis. We have targeted myosin-IC by using small interfering RNA (siRNA) silencing as a therapeutic approach, since it is known that the function of this protein is vital for the amoeba. In this work, specific siRNAs against the Acanthamoeba myosin-IC gene were developed. Treated and control amoebae were cultured in growth and encystment media to evaluate the induced effects after myosin-IC gene knockdown, as we have anticipated that cyst formation may be impaired. The effects of myosin-IC gene silencing were inhibition of cyst formation, inhibition of completion of cytokinesis, inhibition of osmoregulation under osmotic stress conditions, and death of the amoebae. The finding that myosin-IC silencing caused incompletion of cytokinesis is in agreement with earlier suggestions that the protein plays a role in cell locomotion, which is necessary to pull daughter cells apart after mitosis in a process known as "traction-mediated cytokinesis". We conclude that myosin-IC is a very promising potential drug target for the development of much-needed antiamoebal drugs and that it should be further exploited for Acanthamoeba therapy.
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Potential resistant morphotypes of Acanthamoeba castellanii expressed in multipurpose contact lens disinfection systems. Eye Contact Lens 2013; 38:400-5. [PMID: 22858984 DOI: 10.1097/icl.0b013e318261ab1f] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVES The free-living amoeba Acanthamoeba castellanii is a rare cause of contact lens-associated microbial keratitis. The cyst stage of this amoeba is noted for its resistance to disinfection by multipurpose contact lens solutions (MPS). This report examines and reviews the potential survival modes of A. castellanii in MPS. METHODS Trophozoites of A. castellanii (ATCC 30234) at densities from 10 to near 10 were incubated in 3 different MPS in a laminar flow hood for 24 hours at ambient temperatures. The dried films of MPS and phosphate-buffered saline (PBS) controls were examined before and after the addition of a peptone-yeast extract-glucose recovery broth (PYG) for the presence of amoeboid trophozoites and resistance stages over at least 7 days. The parallel exposure of trophozoites to MPS without evaporation or addition of PYG was similarly examined. RESULTS Amoeboid trophozoites were not recovered in PYG nor were cyst-like structures observed in any MPS with near 10 densities. Progressively with 10 to 10 trophozoites, varied survival modes, particularly aggregates of trophozoites associated with cyst-like structures and occasional amoeboid forms and double-walled cysts with ostioles, became more evident. These morphotypes were most prominent after evaporation and typically first observed in the PYG. CONCLUSIONS Trophozoites of A. castellanii near 10 and progressively to 10 densities are capable of expressing a variety of "short-term" survival modes in MPS, notably with the added stress of evaporation. Expression of these alternate survival modes in MPS may relate, in part, to contamination of contact lens cases and difficulties in developing standardized MPS efficacy tests.
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Lorenzo-Morales J, Martín-Navarro CM, López-Arencibia A, Arnalich-Montiel F, Piñero JE, Valladares B. Acanthamoeba keratitis: an emerging disease gathering importance worldwide? Trends Parasitol 2013; 29:181-7. [PMID: 23433689 DOI: 10.1016/j.pt.2013.01.006] [Citation(s) in RCA: 196] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2012] [Revised: 01/23/2013] [Accepted: 01/28/2013] [Indexed: 11/15/2022]
Abstract
Acanthamoeba keratitis (AK) is increasingly being recognized as a severe sight-threatening ocular infection worldwide. Although contact lens wear is the leading risk factor for AK, Acanthamoeba parasites are also an important cause of keratitis in non-contact lens wearers. Diagnosis of AK is challenging, and the available treatments are lengthy and not fully effective against all strains. The pathogenesis of Acanthamoeba is still under study, and the identification of the key factors involved in this process should be useful for the development of fully effective therapies. This review focuses on recent developments on AK pathogenesis and diagnosis as well as novel strategies for the evaluation of anti-amoebic agents that could be applied in the near future against these pathogens.
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Affiliation(s)
- Jacob Lorenzo-Morales
- University Institute of Tropical Diseases and Public Health of The Canary Islands, University of La Laguna, Avenida Astrofísico Francisco Sánchez SN, 38203 La Laguna, Tenerife, Canary Islands, Spain.
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Siddiqui R, Aqeel Y, Khan NA. Killing the dead: chemotherapeutic strategies against free-living cyst-forming protists (Acanthamoeba sp. and Balamuthia mandrillaris). J Eukaryot Microbiol 2013; 60:291-7. [PMID: 23346945 DOI: 10.1111/jeu.12026] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2012] [Revised: 12/14/2012] [Accepted: 12/14/2012] [Indexed: 11/28/2022]
Abstract
The opportunist free-living protists such as Acanthamoeba spp. and Balamuthia mandrillaris have become a serious threat to human life. As most available drugs target functional aspects of pathogens, the ability of free-living protists to transform into metabolically inactive cyst forms presents a challenge in treatment. It is hoped, that the development of broad spectrum antiprotist agents acting against multiple cyst-forming protists to provide target-directed inhibition will offer a viable drug strategy in the treatment of these rare infections. Here, we present a comprehensive report on upcoming drug targets, with emphasis on cyst wall biosynthesis along with the related biochemistry of encystment pathways, as we strive to bring ourselves a step closer to being able to combat these deadly diseases.
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Affiliation(s)
- Ruqaiyyah Siddiqui
- Department of Biological and Biomedical Sciences, Aga Khan University, Karachi, Pakistan
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Szczotka-Flynn L, Ahearn DG, Barr J, Benjamin W(J, Kiang T, Nichols JJ, Schein OD, Stone RP, Winterton L. 1. History, evolution, and evolving standards of contact lens care. Cont Lens Anterior Eye 2013; 36 Suppl 1:S4-8. [DOI: 10.1016/s1367-0484(13)60003-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Chemical composition and amoebicidal activity of Croton pallidulus, Croton ericoides, and Croton isabelli(Euphorbiaceae) essential oils. Parasitol Res 2012; 111:961-6. [DOI: 10.1007/s00436-012-2918-6] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2012] [Accepted: 03/26/2012] [Indexed: 11/30/2022]
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Relationship between aggregation properties and antimicrobial activities of alkylphosphocholines with branched alkyl chains. Int J Pharm 2012; 423:247-56. [DOI: 10.1016/j.ijpharm.2011.11.047] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2011] [Revised: 11/29/2011] [Accepted: 11/30/2011] [Indexed: 11/18/2022]
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Cellular response of the amoeba Acanthamoeba castellanii to chlorine, chlorine dioxide, and monochloramine treatments. Appl Environ Microbiol 2011; 77:4974-80. [PMID: 21602398 DOI: 10.1128/aem.00234-11] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Acanthamoeba castellanii is a free-living amoebae commonly found in water systems. Free-living amoebae might be pathogenic but are also known to bear phagocytosis-resistant bacteria, protecting these bacteria from water treatments. The mode of action of these treatments is poorly understood, particularly on amoebae. It is important to examine the action of these treatments on amoebae in order to improve them. The cellular response to chlorine, chlorine dioxide, and monochloramine was tested on A. castellanii trophozoites. Doses of disinfectants leading to up to a 3-log reduction were compared by flow cytometry and electron microscopy. Chlorine treatment led to size reduction, permeabilization, and retraction of pseudopods. In addition, treatment with chlorine dioxide led to a vacuolization of the cytoplasm. Monochloramine had a dose-dependent effect. At the highest doses monochloramine treatment resulted in almost no changes in cell size and permeability, as shown by flow cytometry, but the cell surface became smooth and dense, as seen by electron microscopy. We show that these disinfectants globally induced size reduction, membrane permeabilization, and morphological modifications but that they have a different mode of action on A. castellanii.
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Sauter IP, dos Santos JC, Apel MA, Cibulski SP, Roehe PM, von Poser GL, Rott MB. Amoebicidal activity and chemical composition of Pterocaulon polystachyum (Asteraceae) essential oil. Parasitol Res 2011; 109:1367-71. [DOI: 10.1007/s00436-011-2383-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2011] [Accepted: 04/06/2011] [Indexed: 11/28/2022]
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