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Heaselgrave W, Kilvington S. The Characterization of an Adrenergic Signalling System Involved in the Encystment of the Ocular Pathogen Acanthamoeba spp. J Eukaryot Microbiol 2016; 63:629-34. [PMID: 26941040 DOI: 10.1111/jeu.12312] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Revised: 02/24/2016] [Accepted: 02/24/2016] [Indexed: 11/29/2022]
Abstract
The aim of this study was to identify and characterize the receptor system involved in controlling encystment in Acanthamoeba using specific agonists and antagonists and to examine whether endogenous stores of catecholamines are produced by the organism. Acanthamoeba trophozoites suspended in axenic growth medium were exposed to adrenoceptor agonists and antagonists to determine which compounds promoted or prevented encystment. Second, trophozoites were cultured in medium containing a catecholamine synthesis inhibitor to investigate the effect this had on natural encystment. Nonspecific adrenoceptor agonists including epinephrine, isoprotenerol, and the selective β1 adrenoceptor agonist dobutamine were found to cause > 90% encystment of Acanthamoeba trophozoites compared to < 30% with the controls. The selective β1 antagonist metoprolol was able to inhibit epinephrine mediated encystment by > 55%. Cultures of Acanthamoeba with the catecholamine synthesis inhibitor α-methyl-p-tyrosine significantly reduced the level of amoebic encystment compared to controls. In conclusion, Acanthamoeba appear to contain a functional adrenergic receptor system of unknown structure which is involved in initiating the encystment process that can be activated and blocked by β1 agonists and antagonists respectively. Furthermore, the presence of this receptor system in Acanthamoeba indicates that topical β adrenoceptor blockers may be effective adjunct therapy by reducing the transformation of trophozoites into the highly resistant cyst stage.
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Affiliation(s)
- Wayne Heaselgrave
- School of Biomedical Science, University of Wolverhampton, MA Building, Wulfruna Street, Wolverhampton, WV1 1LY, United Kingdom
| | - Simon Kilvington
- Department of Infection Immunity and Inflammation, University of Leicester, Medical Sciences Building, University Road, Leicester, LE1 9HN, United Kingdom
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Silva LKDS, Boratto PVM, La Scola B, Bonjardim CA, Abrahão JS. Acanthamoeba and mimivirus interactions: the role of amoebal encystment and the expansion of the 'Cheshire Cat' theory. Curr Opin Microbiol 2016; 31:9-15. [PMID: 26820447 DOI: 10.1016/j.mib.2016.01.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2015] [Revised: 12/28/2015] [Accepted: 01/07/2016] [Indexed: 11/26/2022]
Abstract
Acanthamoeba are natural hosts for giant viruses and their life cycle comprises two stages: a trophozoite and a cryptobiotic cyst. Encystment involves a massive turnover of cellular components under molecular regulation. Giant viruses are able to infect only the trophozoite, while cysts are resistant to infection. Otherwise, upon infection, mimiviruses are able to prevent encystment. This review highlights the important points of Acanthamoeba and giant virus interactions regarding the encystment process. The existence of an acanthamoebal non-permissive cell for Acanthamoeba polyphaga mimivirus, the prototype member of the Mimivirus genus, is analyzed at the molecular and ecological levels, and compared to a similar phenomenon previously described for Emiliana huxleyi and its associated phycodnaviruses: the 'Cheshire Cat' escape strategy.
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Affiliation(s)
- Ludmila Karen Dos Santos Silva
- Laboratório de Vírus, Departamento de Microbiologia, Instituto de Ciências Biológicas (ICB), Universidade Federal de Minas Gerais, Brasil (UFMG), Postal code 486, Belo Horizonte, Minas Gerais, Brazil
| | - Paulo Victor Miranda Boratto
- Laboratório de Vírus, Departamento de Microbiologia, Instituto de Ciências Biológicas (ICB), Universidade Federal de Minas Gerais, Brasil (UFMG), Postal code 486, Belo Horizonte, Minas Gerais, Brazil
| | - Bernard La Scola
- URMITE CNRS UMR 6236-IRD 3R198, Aix Marseille Universite, Marseille, France
| | - Cláudio Antônio Bonjardim
- Laboratório de Vírus, Departamento de Microbiologia, Instituto de Ciências Biológicas (ICB), Universidade Federal de Minas Gerais, Brasil (UFMG), Postal code 486, Belo Horizonte, Minas Gerais, Brazil
| | - Jônatas Santos Abrahão
- Laboratório de Vírus, Departamento de Microbiologia, Instituto de Ciências Biológicas (ICB), Universidade Federal de Minas Gerais, Brasil (UFMG), Postal code 486, Belo Horizonte, Minas Gerais, Brazil.
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Fouque E, Trouilhé MC, Thomas V, Humeau P, Héchard Y. Encystment of Vermamoeba (Hartmannella) vermiformis: Effects of environmental conditions and cell concentration. Exp Parasitol 2014; 145 Suppl:S62-8. [PMID: 24721257 DOI: 10.1016/j.exppara.2014.03.029] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2013] [Revised: 03/24/2014] [Accepted: 03/31/2014] [Indexed: 11/28/2022]
Abstract
Vermamoeba vermiformis is a free-living amoeba (FLA) which is widely distributed in the environment. It is known to colonize water systems and to be a reservoir of pathogenic bacteria, such as Legionella pneumophila. For these reasons the control of V. vermiformis represents an important health issue. However, FLA may be resistant to disinfection treatments due to the process of encystment. Thereby, it is important to better understand factors influencing this process. In this aim, we investigated the effect of temperature, pH, osmotic pressure and cell concentration on the encystment of two V. vermiformis strains. Encystment was quite fast, with a 100% encystment rate being observed after 9h of incubation. For the two strains, an optimal encystment was obtained at 25 and 37°C. Concerning pH and osmotic pressure, there were different effects on the encystment according to the tested strains. For the reference strain (ATCC 50237), the patterns of encystment were similar for pH comprised between 5 and 9 and for KCl concentrations ranging from 0.05 to 0.2 mol L(-1). For the environmental strain (172A) an optimal encystment was obtained for basic pH (8 and 9) and for a concentration in KCl of 0.1 mol L(-1). The results also clearly demonstrated that the encystment rate increased with cell concentration, suggesting that there is an inter-amoebal communication. The present study establish for the first time environmental conditions favoring encystment and would lay the foundations to better control the encystment of V. vermiformis.
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Affiliation(s)
- Emilie Fouque
- Université de Poitiers, UMR CNRS 7267, Ecologie et Biologie des Interactions (EBI), Equipe Microbiologie de l'Eau, 1 rue G. Bonnet, 86073 Poitiers Cedex, France; Scientific and Technical Center for Building, AQUASIM, 11 rue Henri Picherit, BP 82341, 44323 Nantes Cedex 3, France
| | - Marie-Cécile Trouilhé
- Scientific and Technical Center for Building, AQUASIM, 11 rue Henri Picherit, BP 82341, 44323 Nantes Cedex 3, France
| | - Vincent Thomas
- Enterome, 94-96 Avenue Ledru Rollin, 75011 Paris, France
| | - Philippe Humeau
- Scientific and Technical Center for Building, AQUASIM, 11 rue Henri Picherit, BP 82341, 44323 Nantes Cedex 3, France
| | - Yann Héchard
- Université de Poitiers, UMR CNRS 7267, Ecologie et Biologie des Interactions (EBI), Equipe Microbiologie de l'Eau, 1 rue G. Bonnet, 86073 Poitiers Cedex, France.
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Cellular, biochemical, and molecular changes during encystment of free-living amoebae. EUKARYOTIC CELL 2012; 11:382-7. [PMID: 22366126 DOI: 10.1128/ec.05301-11] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Free-living amoebae are protozoa found in soil and water. Among them, some are pathogenic and many have been described as potential reservoirs of pathogenic bacteria. Their cell cycle is divided into at least two forms, the trophozoite and the cyst, and the differentiation process is named encystment. As cysts are more resistant to disinfection treatments than trophozoites, many studies focused on encystment, but until recently, little was known about cellular, biochemical, and molecular modifications operating during this process. Important signals and signaling pathways at play during encystment, as well as cell responses at the molecular level, have been described. This review summarizes our knowledge and focuses on new findings.
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Thomas V, McDonnell G, Denyer SP, Maillard JY. Free-living amoebae and their intracellular pathogenic microorganisms: risks for water quality. FEMS Microbiol Rev 2010; 34:231-59. [DOI: 10.1111/j.1574-6976.2009.00190.x] [Citation(s) in RCA: 208] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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Mathis A, Wild P, Deplazes P, Boettger EC. The mitochondrial ribosome of the protozoan Acanthamoeba castellanii is the target for macrolide antibiotics. Mol Biochem Parasitol 2004; 135:225-9. [PMID: 15110464 DOI: 10.1016/j.molbiopara.2004.02.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2003] [Revised: 02/06/2004] [Accepted: 02/24/2004] [Indexed: 11/20/2022]
Affiliation(s)
- Alexander Mathis
- Institute of Parasitology, University of Zürich, Winterthurerstrasse 266A, 8057 Zürich, Switzerland.
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IN MEMORIAM: THOMAS J. BYERS (1935-2003). J Eukaryot Microbiol 2004. [DOI: 10.1111/j.1550-7408.2004.tb00403.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Lloyd D, Turner NA, Khunkitti W, Hann AC, Furr JR, Russell AD. Encystation in Acanthamoeba castellanii: development of biocide resistance. J Eukaryot Microbiol 2001; 48:11-6. [PMID: 11249185 DOI: 10.1111/j.1550-7408.2001.tb00410.x] [Citation(s) in RCA: 79] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Since the early 1960s, axenic culture and the development of procedures for the induction of encystation have made Acanthamoeba spp. superb experimental systems for studies of cell biology and differentiation. More recently, since their roles as human pathogens causing keratitis and encephalitis have become widely recognized, it has become urgent to understand the parameters that determine differentiation, as cysts are much more resistant to biocides than are the trophozoites. Viability of trophozoites of the soil amoeba Acanthamoeba castellanii (Neff), is conveniently measured by its ability to form plaques on a lawn of Escherichia coli. Use of confocal laser scanning microscopy with Calcofluor white, Congo Red or the anionic oxonol dye, DiBAC4(3) or flow cytometry with propidium iodide diacetate and fluorescein or oxonol provides more rapid assessment. For cysts, the plaque method is still the best, because dye exclusion does not necessarily indicate viability and therefore the plate count method has been used to study the sequence of development of biocide resistance during the differentiation process. After two hours, resistance to HCl was apparent. Polyhexamethylene biguanide, benzalkonium chloride, propamidine isethionate, pentamidine isethionate, dibromopropamine isethionate, and H2O2 and moist heat, all lost effectiveness at between 14 and 24 h after trophozoites were inoculated into encystation media. Chlorhexidine diacetate resistance was observed at between 24 and 36 h. The molecular biology and biochemistry of the modifications that underlie these changes are now being investigated.
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Affiliation(s)
- D Lloyd
- Department of Microbiology, School of Biosciences, Cardiff University, Wales, United Kingdom.
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Abstract
Free-living amoebae of the genus Acanthamoeba produce a progressive, blinding infection of the corneal surface. The pathogenesis of Acanthamoeba keratitis involves parasite-mediated cytolysis and phagocytosis of corneal epithelial cells and induction of programmed cell death. Acanthamoeba spp. elaborate a variety of proteases which may facilitate cytolysis of the corneal epithelium, invasion of the extracellular matrix, and dissolution of the corneal stromal matrix.
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Affiliation(s)
- J Y Niederkorn
- Southwestern Medical School, 5323 Harry Hines Blvd, Dallas, Texas 75235-9057, USA
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Hay J, Kirkness CM, Seal DV, Wright P. Drug resistance and Acanthamoeba keratitis: the quest for alternative antiprotozoal chemotherapy. Eye (Lond) 1994; 8 ( Pt 5):555-63. [PMID: 7835453 DOI: 10.1038/eye.1994.137] [Citation(s) in RCA: 115] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Trophozoites and cysts of 20 isolates of Acanthamoeba from the cornea and five from related samples were tested in vitro for sensitivity to ten drugs (three aromatic diamidines, two aminoglycosides, two macrolides, a polyene macrolide antibiotic, an organoarsenical and an antimetabolite) and two cationic antiseptics (chlorhexidine and polyhexamethylene biguanide, PHMB). Only chlorhexidine and PHMB showed uniform amoebacidal activity. Aromatic diamidines (pentamidine isethionate, propamidine isethionate and diminazene aceturate) generally proved effective against both forms of the amoeba; only pentamidine gave synergy with the biguanide while propamidine gave an additive effect. Other drugs tested proved erratic or ineffective against different isolates. Chlorhexidine alone, or together with propamidine, was subsequently used in two patients with proven Acanthamoeba keratitis; the causative isolates were sensitive to the individual compounds and to the combination in vitro. The treatment provided resolution of the clinical disease; amoebae were shown to be nonviable by histology and culture. The combination of chlorhexidine and propamidine is recommended for treatment of proven Acanthamoeba keratitis.
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Affiliation(s)
- J Hay
- Department of Bacteriology, Royal Infirmary, Glasgow, UK
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Hugo ER, Byers TJ. S-adenosyl-L-methionine decarboxylase of Acanthamoeba castellanii (Neff): purification and properties. Biochem J 1993; 295 ( Pt 1):203-9. [PMID: 8216217 PMCID: PMC1134839 DOI: 10.1042/bj2950203] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
S-Adenosyl-L-methionine decarboxylase (AdoMetDC) has been purified to near homogeneity from the Neff strain of Acanthamoeba castellanii. The holoenzyme molecular mass is 88.8 kDa, including two copies each of a 32.8 kDa alpha-subunit and a 10-15 kDa beta-subunit. The alpha-subunit contains the active site. It has an N-terminal pyruvoyl group, and the first 19 amino acids are 63 and 74% identical with comparable sequences from yeast and mammals, respectively. The apparent Km for S-adenosylmethionine (AdoMet) in the presence of 2 mM putrescine was 30.0 microM. The enzyme was stimulated 2-fold by putrescine, but was unaffected by spermidine. It was inhibited by the following anti-metabolites, listed with their Ki values: Berenil (0.17 microM), pentamidine (19.4 microM), propamidine (334 microM), hydroxystilbamidine (357 microM), methylglyoxal bis(guanylhydrazone) (604 microM) and ethidium bromide (1.3 mM). Activity of the enzyme fell to undetectable levels during cell differentiation (encystment).
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Affiliation(s)
- E R Hugo
- Department of Molecular Genetics, Ohio State University, Columbus 43210
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LASMAN MARIA. Encystment-Inducing Factor from Cultures of Acanthamoeba palestinensis. (Acanthamoeba palestinensis/growth/cyst formation/encystment-inducing factor). Dev Growth Differ 1987. [DOI: 10.1111/j.1440-169x.1987.00547.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Kim BG, Sobota A, Bitonti AJ, McCann PP, Byers TJ. Polyamine metabolism in Acanthamoeba: polyamine content and synthesis of ornithine, putrescine, and diaminopropane. THE JOURNAL OF PROTOZOOLOGY 1987; 34:278-84. [PMID: 3656216 DOI: 10.1111/j.1550-7408.1987.tb03175.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Five polyamines which could be separated by high performance liquid chromatography were found in Acanthamoeba castellanii (strain Neff). These included in order of decreasing abundance: 1,3-diaminopropane, spermidine, spermine, norspermidine, and putrescine. Only diaminopropane and norspermidine had been found previously. Spermine was present in cultures grown in broth, but not in defined medium. Radioactive substrates were used to establish that putrescine was synthesized by decarboxylation of ornithine, ornithine was synthesized from arginine or citrulline, and diaminopropane was synthesized from spermidine. The presence of ornithine decarboxylase (EC 4.1.1.17), arginase (EC 3.5.3.1), and urease (EC 3.5.1.5) and the absence of arginine decarboxylase (EC 4.1.1.19) were established. A scheme for polyamine biosynthesis in A. castellanii is proposed.
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Affiliation(s)
- B G Kim
- Department of Microbiology, Ohio State University, Columbus 43210
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Kim BG, McCann PP, Byers TJ. Inhibition of multiplication in Acanthamoeba castellanii by specific inhibitors of ornithine decarboxylase. THE JOURNAL OF PROTOZOOLOGY 1987; 34:264-6. [PMID: 3116220 DOI: 10.1111/j.1550-7408.1987.tb03172.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Proliferation of Acanthamoeba castellanii (Neff strain) in either a broth medium or a defined medium was arrested by alpha-monofluoromethyldehydroornithine (delta-MFMOme), alpha-difluoromethylornithine (DFMO), and (R,R')-delta-methyl-alpha-acetylenic putrescine (MAP), three specific inhibitors of ornithine decarboxylase. Although all three inhibited the ameba enzyme, delta-MFMOme was the most effective inhibitor of multiplication. Growth inhibition was reversed by the addition of polyamines. The inhibitors did not induce differentiation by themselves although DFMO caused encystment when supplemented with CaCl2 or MgSO4.
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Affiliation(s)
- B G Kim
- Department of Microbiology, Ohio State University, Columbus 43210
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Abstract
A pheromone is a chemical excreted by an organism into the environment that acts to elicit a specific response from other organisms of the same species. The importance of pheromones in the life cycle of various species of mammals, insects, and fungi is well known. In the past decade, it has become apparent that pheromones influence the behavior and development of prokaryotes. Pheromones excreted by myxobacteria, actinomycetes, and cyanobacteria elicit specific developmental responses from these organisms. In addition, pheromones excreted by Streptococcus faecalis function in conjugation, and pheromones of luminescent bacteria regulate bioluminescence of these organisms.
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Bogler SA, Zarley CD, Burianek LL, Fuerst PA, Byers TJ. Interstrain mitochondrial DNA polymorphism detected in Acanthamoeba by restriction endonuclease analysis. Mol Biochem Parasitol 1983; 8:145-63. [PMID: 6308443 DOI: 10.1016/0166-6851(83)90006-3] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The genus Acanthamoeba includes pathogenic and nonpathogenic strains of amebas with unclear taxonomic and evolutionary relationships. To explore these relationships further, we have examined mitochondrial DNA fragment patterns obtained for 15 Acanthamoeba strains by use of five restriction endonucleases. The mitochondrial DNA molecules were circular, averaging 41.6 +/- 1.5 kilobase pairs. Fragments resulting from endonuclease digestion of the DNA were separated by agarose gel electrophoresis. Ten distinct families of electrophoretic patterns (digestion phenotypes) were observed. Seven phenotypes were found for seven strains considered nonpathogenic or of unknown pathogenicity. Three phenotypes were associated with pathogenic strains. One of these phenotypes included a single pathogenic strain, a second included one pathogen and one strain of unknown pathogenicity, and the third included five pathogenic strains. The latter five were of widespread geographic origin and previously were assigned to two different species. The results suggest that extensive nucleotide sequence diversity occurs among strains from a single species of Acanthamoeba, but that subgroups of strains with similar sequences also occur. Thus, restriction enzyme analysis can identify clusters of strains and may be a useful approach to classification in the genus. Improvements in classification should help clarify relationships among pathogenic and non-pathogenic strains.
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