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Ilyas M, Stapleton F, Willcox MDP, Henriquez F, Peguda HK, Rayamajhee B, Zahid T, Petsoglou C, Carnt NA. Epidemiology of and Genetic Factors Associated with Acanthamoeba Keratitis. Pathogens 2024; 13:142. [PMID: 38392880 PMCID: PMC10892102 DOI: 10.3390/pathogens13020142] [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: 12/15/2023] [Revised: 01/14/2024] [Accepted: 01/31/2024] [Indexed: 02/25/2024] Open
Abstract
Acanthamoeba keratitis (AK) is a severe, rare protozoal infection of the cornea. Acanthamoeba can survive in diverse habitats and at extreme temperatures. AK is mostly seen in contact lens wearers whose lenses have become contaminated or who have a history of water exposure, and in those without contact lens wear who have experienced recent eye trauma involving contaminated soil or water. Infection usually results in severe eye pain, photophobia, inflammation, and corneal epithelial defects. The pathophysiology of this infection is multifactorial, including the production of cytotoxic proteases by Acanthamoeba that degrades the corneal epithelial basement membrane and induces the death of ocular surface cells, resulting in degradation of the collagen-rich corneal stroma. AK can be prevented by avoiding risk factors, which includes avoiding water contact, such as swimming or showering in contact lenses, and wearing protective goggles when working on the land. AK is mostly treated with an antimicrobial therapy of biguanides alone or in combination with diaminidines, although the commercial availability of these medicines is variable. Other than anti-amoeba therapies, targeting host immune pathways in Acanthamoeba disease may lead to the development of vaccines or antibody therapeutics which could transform the management of AK.
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Affiliation(s)
- Muhammad Ilyas
- Primary & Secondary Healthcare Department, Punjab 54000, Pakistan; (M.I.)
| | - Fiona Stapleton
- School of Optometry and Vision Science, University of NSW, Sydney, NSW 2052, Australia (H.K.P.)
| | - Mark D. P. Willcox
- School of Optometry and Vision Science, University of NSW, Sydney, NSW 2052, Australia (H.K.P.)
| | - Fiona Henriquez
- School of Health and Life Sciences, The University of the West of Scotland, Glasgow G72 0LH, UK
| | - Hari Kumar Peguda
- School of Optometry and Vision Science, University of NSW, Sydney, NSW 2052, Australia (H.K.P.)
| | - Binod Rayamajhee
- School of Optometry and Vision Science, University of NSW, Sydney, NSW 2052, Australia (H.K.P.)
| | - Tasbiha Zahid
- Primary & Secondary Healthcare Department, Punjab 54000, Pakistan; (M.I.)
| | | | - Nicole A. Carnt
- School of Optometry and Vision Science, University of NSW, Sydney, NSW 2052, Australia (H.K.P.)
- Centre for Vision Research, Westmead Institute for Medical Research, Sydney, NSW 2145, Australia
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Wang Y, Jiang L, Zhao Y, Ju X, Wang L, Jin L, Fine RD, Li M. Biological characteristics and pathogenicity of Acanthamoeba. Front Microbiol 2023; 14:1147077. [PMID: 37089530 PMCID: PMC10113681 DOI: 10.3389/fmicb.2023.1147077] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Accepted: 03/21/2023] [Indexed: 04/25/2023] Open
Abstract
Acanthamoeba is an opportunistic protozoa, which exists widely in nature and is mainly distributed in soil and water. Acanthamoeba usually exists in two forms, trophozoites and cysts. The trophozoite stage is one of growth and reproduction while the cyst stage is characterized by cellular quiescence, commonly resulting in human infection, and the lack of effective monotherapy after initial infection leads to chronic disease. Acanthamoeba can infect several human body tissues such as the skin, cornea, conjunctiva, respiratory tract, and reproductive tract, especially when the tissue barriers are damaged. Furthermore, serious infections can cause Acanthamoeba keratitis, granulomatous amoebic encephalitis, skin, and lung infections. With an increasing number of Acanthamoeba infections in recent years, the pathogenicity of Acanthamoeba is becoming more relevant to mainstream clinical care. This review article will describe the etiological characteristics of Acanthamoeba infection in detail from the aspects of biological characteristic, classification, disease, and pathogenic mechanism in order to provide scientific basis for the diagnosis, treatment, and prevention of Acanthamoeba infection.
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Affiliation(s)
- Yuehua Wang
- College of Laboratory Medicine, Jilin Medical University, Jilin City, China
| | - Linzhe Jiang
- General Surgery, Jilin People’s Hospital, Jilin City, China
| | - Yitong Zhao
- College of Laboratory Medicine, Jilin Medical University, Jilin City, China
| | - Xiaohong Ju
- College of Laboratory Medicine, Jilin Medical University, Jilin City, China
| | - Le Wang
- Department of Laboratory Medicine, Jilin Hospital of Integrated Chinese and Western Medicine, Jilin City, China
| | - Liang Jin
- Department of Laboratory Medicine, Jilin Hospital of Integrated Chinese and Western Medicine, Jilin City, China
| | - Ryan D. Fine
- Center for Human Genetics and Genomics, New York University Grossman School of Medicine, New York City, NY, United States
| | - Mingguang Li
- College of Laboratory Medicine, Jilin Medical University, Jilin City, China
- *Correspondence: Mingguang Li,
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Gonçalves DDS, Ferreira MDS, Gomes KX, Rodríguez‐de La Noval C, Liedke SC, Costa GCV, Albuquerque P, Cortines JR, Saramago Peralta RH, Peralta JM, Casadevall A, Guimarães AJ. Unravelling the interactions of the environmental hostAcanthamoeba castellaniiwith fungi through the recognition by mannose‐binding proteins. Cell Microbiol 2019; 21:e13066. [DOI: 10.1111/cmi.13066] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Accepted: 06/04/2019] [Indexed: 12/12/2022]
Affiliation(s)
- Diego de Souza Gonçalves
- Department of Microbiology and Parasitology, Biomedical InstituteFluminense Federal University Niterói Brazil
| | - Marina da Silva Ferreira
- Department of Immunology, Paulo de Góes Microbiology InstituteFederal University of Rio de Janeiro Rio de Janeiro Brazil
| | - Kamilla Xavier Gomes
- Department of Microbiology and Parasitology, Biomedical InstituteFluminense Federal University Niterói Brazil
| | - Claudia Rodríguez‐de La Noval
- Department of Immunology, Paulo de Góes Microbiology InstituteFederal University of Rio de Janeiro Rio de Janeiro Brazil
| | - Susie Coutinho Liedke
- Department of Immunology, Paulo de Góes Microbiology InstituteFederal University of Rio de Janeiro Rio de Janeiro Brazil
| | - Giovani Carlo Veríssimo Costa
- Department of Immunology, Paulo de Góes Microbiology InstituteFederal University of Rio de Janeiro Rio de Janeiro Brazil
| | | | - Juliana Reis Cortines
- Department of Virology, Paulo de Góes Microbiology InstituteFederal University of Rio de Janeiro Rio de Janeiro Brazil
| | | | - José Mauro Peralta
- Department of Immunology, Paulo de Góes Microbiology InstituteFederal University of Rio de Janeiro Rio de Janeiro Brazil
| | - Arturo Casadevall
- Department of Molecular Microbiology and ImmunologyJohns Hopkins Bloomberg School of Public Health Baltimore Maryland
| | - Allan J. Guimarães
- Department of Microbiology and Parasitology, Biomedical InstituteFluminense Federal University Niterói Brazil
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Martín-Pérez T, Criado-Fornelio A, Ávila-Blanco M, Pérez-Serrano J. Development and optimization of new culture media for Acanthamoeba spp. (Protozoa: Amoebozoa). Eur J Protistol 2018; 64:91-102. [PMID: 29730482 DOI: 10.1016/j.ejop.2018.04.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Revised: 04/04/2018] [Accepted: 04/06/2018] [Indexed: 10/17/2022]
Abstract
The isolation and growth in axenic liquid media of Acanthamoeba strains is necessary in order to carry out primary in vitro drug screening. Amoebic isolates which are hard to grow in the current liquid media have been reported. Such circumstances hampers the ability of conducting drug sensitivity tests. Therefore, finding suitable universal growth media for Acanthamoeba species is required. The present study was aimed at the development of liquid medium suitable for growing a fastidious (F) genotype T3 Acanthamoeba isolate, and eventually for other genotypes of this genus as well. Trophozoite growth was indirectly monitored by respiration analysis with oxygen-sensitive microplates (OSM) and further confirmed by manual counting. Media were empirically designed and tested first in a non-fastidious (NF) T3 isolate and then tested with 14 different strains, including the fastidious one. Combinations of nutritive components such as meat/vegetable broth, LB medium, malt and skimmed milk led to the design of new media suitable for culturing all the isolates tested, in conditions similar to those obtained in standard culture media such as PYG or CERVA.
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Affiliation(s)
- Tania Martín-Pérez
- Departamento de Biomedicina y Biotecnología, Laboratorio de Parasitología, Grupo ECOMYP, Facultad de Farmacia, Universidad de Alcalá, 28805 Alcalá de Henares, Madrid, Spain.
| | - Angel Criado-Fornelio
- Departamento de Biomedicina y Biotecnología, Laboratorio de Parasitología, Grupo ECOMYP, Facultad de Farmacia, Universidad de Alcalá, 28805 Alcalá de Henares, Madrid, Spain
| | - Manuel Ávila-Blanco
- Departamento de Biomedicina y Biotecnología, Laboratorio de Parasitología, Grupo ECOMYP, Facultad de Farmacia, Universidad de Alcalá, 28805 Alcalá de Henares, Madrid, Spain; Laboratorio de ciencias morfológicas, Departamento de Morfología, Centro de Ciencias Básicas, Universidad Autónoma de Aguascalientes, Ciudad Universitaria, Aguascalientes, Ags., México
| | - Jorge Pérez-Serrano
- Departamento de Biomedicina y Biotecnología, Laboratorio de Parasitología, Grupo ECOMYP, Facultad de Farmacia, Universidad de Alcalá, 28805 Alcalá de Henares, Madrid, Spain
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5
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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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Development of an immunochromatographic assay kit using fluorescent silica nanoparticles for rapid diagnosis of Acanthamoeba keratitis. J Clin Microbiol 2014; 53:273-7. [PMID: 25392356 DOI: 10.1128/jcm.02595-14] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We developed an immunochromatographic assay kit that uses fluorescent silica nanoparticles bound to anti-Acanthamoeba antibodies (fluorescent immunochromatographic assay [FICGA]) and evaluated its efficacy for the detection of Acanthamoeba and diagnosis of Acanthamoeba keratitis (AK). The sensitivity of the FICGA kit was evaluated using samples of Acanthamoeba trophozoites and cysts diluted to various concentrations. A conventional immunochromatographic assay kit with latex labels (LICGA) was also evaluated to determine its sensitivity in detecting Acanthamoeba trophozoites. To check for cross-reactivity, the FICGA was performed by using samples of other common causative pathogens of infectious keratitis, such as Pseudomonas aeruginosa, Staphylococcus aureus, Staphylococcus epidermidis, and Candida albicans. Corneal scrapings from patients with suspected AK were tested with the FICGA kit to detect the presence of Acanthamoeba, and the results were compared with those of real-time PCR. The FICGA kit detected organisms at concentrations as low as 5 trophozoites or 40 cysts per sample. There were no cross-reactivities with other pathogens. The FICGA was approximately 20 times more sensitive than the LICGA for the detection of Acanthamoeba trophozoites. The FICGA kit yielded positive results for all 10 patients, which corresponded well with the real-time PCR results. The FICGA kit demonstrated high sensitivity for the detection of Acanthamoeba and may be useful for the diagnosis of AK.
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7
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Entamoeba histolytica adaptation to glucose starvation: a matter of life and death. Curr Opin Microbiol 2014; 20:139-45. [DOI: 10.1016/j.mib.2014.06.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2014] [Revised: 06/11/2014] [Accepted: 06/13/2014] [Indexed: 12/25/2022]
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Taylor BP, Cortez MH, Weitz JS. The virus of my virus is my friend: ecological effects of virophage with alternative modes of coinfection. J Theor Biol 2014; 354:124-36. [PMID: 24662503 DOI: 10.1016/j.jtbi.2014.03.008] [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: 12/20/2013] [Accepted: 03/06/2014] [Indexed: 10/25/2022]
Abstract
Virophages are viruses that rely on the replication machinery of other viruses to reproduce within eukaryotic hosts. Two different modes of coinfection have been posited based on experimental observation. In one mode, the virophage and the virus enter the host independently. In the other mode, the virophage adheres to the virus so both virophage and virus enter the host together. Here we ask: what are the ecological effects of these different modes of coinfection? In particular, what ecological effects are common to both infection modes, and what are the differences particular to each mode? We develop a pair of biophysically motivated ODE models of viral-host population dynamics, corresponding to dynamics arising from each mode of infection. We find that both modes of coinfection allow for the coexistence of the virophage, virus, and host either at a stable fixed point or through cyclical dynamics. In both models, virophage tends to be the most abundant population and their presence always reduces the viral abundance and increases the host abundance. However, we do find qualitative differences between models. For example, via extensive sampling of biologically relevant parameter space, we only observe bistability when the virophage and the virus enter the host together. We discuss how such differences may be leveraged to help identify modes of infection in natural environments from population level data.
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Affiliation(s)
- Bradford P Taylor
- School of Physics, Georgia Institute of Technology, Atlanta, GA, USA
| | - Michael H Cortez
- School of Biology, Georgia Institute of Technology, Atlanta, GA, USA
| | - Joshua S Weitz
- School of Biology, Georgia Institute of Technology, Atlanta, GA, USA; School of Physics, Georgia Institute of Technology, Atlanta, GA, USA.
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9
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Sixt BS, Siegl A, Müller C, Watzka M, Wultsch A, Tziotis D, Montanaro J, Richter A, Schmitt-Kopplin P, Horn M. Metabolic features of Protochlamydia amoebophila elementary bodies--a link between activity and infectivity in Chlamydiae. PLoS Pathog 2013; 9:e1003553. [PMID: 23950718 PMCID: PMC3738481 DOI: 10.1371/journal.ppat.1003553] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2013] [Accepted: 06/28/2013] [Indexed: 01/07/2023] Open
Abstract
The Chlamydiae are a highly successful group of obligate intracellular bacteria, whose members are remarkably diverse, ranging from major pathogens of humans and animals to symbionts of ubiquitous protozoa. While their infective developmental stage, the elementary body (EB), has long been accepted to be completely metabolically inert, it has recently been shown to sustain some activities, including uptake of amino acids and protein biosynthesis. In the current study, we performed an in-depth characterization of the metabolic capabilities of EBs of the amoeba symbiont Protochlamydia amoebophila. A combined metabolomics approach, including fluorescence microscopy-based assays, isotope-ratio mass spectrometry (IRMS), ion cyclotron resonance Fourier transform mass spectrometry (ICR/FT-MS), and ultra-performance liquid chromatography mass spectrometry (UPLC-MS) was conducted, with a particular focus on the central carbon metabolism. In addition, the effect of nutrient deprivation on chlamydial infectivity was analyzed. Our investigations revealed that host-free P. amoebophila EBs maintain respiratory activity and metabolize D-glucose, including substrate uptake as well as host-free synthesis of labeled metabolites and release of labeled CO2 from 13C-labeled D-glucose. The pentose phosphate pathway was identified as major route of D-glucose catabolism and host-independent activity of the tricarboxylic acid (TCA) cycle was observed. Our data strongly suggest anabolic reactions in P. amoebophila EBs and demonstrate that under the applied conditions D-glucose availability is essential to sustain metabolic activity. Replacement of this substrate by L-glucose, a non-metabolizable sugar, led to a rapid decline in the number of infectious particles. Likewise, infectivity of Chlamydia trachomatis, a major human pathogen, also declined more rapidly in the absence of nutrients. Collectively, these findings demonstrate that D-glucose is utilized by P. amoebophila EBs and provide evidence that metabolic activity in the extracellular stage of chlamydiae is of major biological relevance as it is a critical factor affecting maintenance of infectivity. The Chlamydiae are a group of bacteria that strictly rely on eukaryotic host cells as a niche for intracellular growth. This group includes major pathogens of humans and animals as well as symbionts of protists. Unlike most other bacteria, chlamydiae alternate between two distinct developmental stages. Here we provide novel insights into the infective stage, the elementary body (EB), which has been described almost a century ago and is commonly referred to as an inert spore-like particle. Our analyses of EBs of the amoeba symbiont Protochlamydia amoebophila provide a detailed overview of their metabolism outside of, and independent from, their natural host cells. We demonstrated that these EBs are capable of respiration and are active in the major routes of central carbon metabolism, including glucose import, biosynthetic reactions, and catabolism for energy generation. Glucose starvation resulted in a rapid decline of metabolic activity in P. amoebophila EBs and a concomitant decrease in their potential to infect new host cells. The human pathogen Chlamydia trachomatis was also dependent on nutrient availability for extracellular survival. The extent of metabolic activity in chlamydial EBs and its consequences for infectivity challenge long-standing textbook knowledge and demonstrate that the infective stage is far more dependent on its environment than previously recognized.
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Affiliation(s)
- Barbara S. Sixt
- Division of Microbial Ecology, Department of Microbiology and Ecosystem Science, University of Vienna, Vienna, Austria
| | - Alexander Siegl
- Division of Microbial Ecology, Department of Microbiology and Ecosystem Science, University of Vienna, Vienna, Austria
| | - Constanze Müller
- Research Unit Analytical BioGeoChemistry, Helmholtz Zentrum München, Neuherberg, Germany
| | - Margarete Watzka
- Division of Terrestrial Ecosystem Research, Department of Microbiology and Ecosystem Science, University of Vienna, Vienna, Austria
| | - Anna Wultsch
- Division of Microbial Ecology, Department of Microbiology and Ecosystem Science, University of Vienna, Vienna, Austria
| | - Dimitrios Tziotis
- Research Unit Analytical BioGeoChemistry, Helmholtz Zentrum München, Neuherberg, Germany
| | - Jacqueline Montanaro
- Division of Microbial Ecology, Department of Microbiology and Ecosystem Science, University of Vienna, Vienna, Austria
| | - Andreas Richter
- Division of Terrestrial Ecosystem Research, Department of Microbiology and Ecosystem Science, University of Vienna, Vienna, Austria
| | | | - Matthias Horn
- Division of Microbial Ecology, Department of Microbiology and Ecosystem Science, University of Vienna, Vienna, Austria
- * E-mail:
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Heredero-Bermejo I, San Juan Martin C, Soliveri de Carranza J, Copa-Patiño JL, Pérez-Serrano J. Acanthamoeba castellanii: in vitro UAH-T17c3 trophozoite growth study in different culture media. Parasitol Res 2012; 110:2563-7. [PMID: 22231263 DOI: 10.1007/s00436-011-2761-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2011] [Accepted: 12/05/2011] [Indexed: 11/29/2022]
Abstract
Acanthamoeba is one of the most common free-living amoebae. It is widespread in the environment and can infect humans, causing diseases such as keratitis and encephalitis. In this study, we used a strain of Acanthamoeba castellanii (UAH-T17c3) isolated from cooling towers, and we evaluated the efficiency of three different culture media in its growth, with the aim of selecting one which allowed better growth, was easier to prepare, and was able to keep the trophozoites by long periods of time. We compared the growth of A. castellanii in peptone-yeast extract-glucose (PYG, the most commonly used medium to grow this strain) to the growth in PYG-Bactocasitone (PYG with 2% Bactocasitone) and brain-heart infusion broth (BHI is a standard microbiological medium rarely used in the culture of amoebae). Flow cytometry and cell count results showed all three media allowed the growth of trophozoites. PYG-Bactocasitone was shown to be the best for long-term culture. The BHI and PYG-Bactocasitone media have not been used for Acanthamoeba spp. trophozoite growth. In view of the results, we can affirm that these media are adequate to grow the above-mentioned strain for in vitro screening assays.
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Affiliation(s)
- I Heredero-Bermejo
- Department of Microbiology and Parasitology, Facultad de Farmacia, Universidad de Alcala, Ctra. Madrid-Barcelona (Autovía A2) Km. 33,600, 28871, Alcalá de Henares, Madrid, Spain
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11
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Cyst and encystment in protozoan parasites: optimal targets for new life-cycle interrupting strategies? Trends Parasitol 2011; 27:450-8. [PMID: 21775209 DOI: 10.1016/j.pt.2011.06.003] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2011] [Revised: 06/15/2011] [Accepted: 06/16/2011] [Indexed: 11/24/2022]
Abstract
Certain protozoan parasites use survival strategies to reside outside the host such as the formation of cysts. This dormant and resistant stage results from the complex process of encystment that involves diverse molecular and cellular modifications. The stimuli and changes associated with cyst biogenesis are a matter of ongoing studies in human and animal protozoan parasites such as amoeba and Giardia species because blocking every step in the encystment pathway should, in theory, interrupt their life cycles. The present review thoroughly examines this essential process in those protozoan parasites and discusses the possibility of using that information to develop new kinds of anti-parasite specific and life cycle-interrupting drugs, aimed at holding back the dissemination of these infections.
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12
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Fulton C, Webster C, Wu JS. Chemically defined media for cultivation of Naegleria gruberi. Proc Natl Acad Sci U S A 2010; 81:2406-10. [PMID: 16593456 PMCID: PMC345069 DOI: 10.1073/pnas.81.8.2406] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Cultivation of amebae of the axenic strain of Naegleria gruberi, NEG-M, was achieved in media consisting entirely of chemically defined components. A complete medium that contains 31 components allows growth with yields up to 5 x 10(6) amebae per ml. A minimal medium gives lower yields but defines 22 components that are essential for continuous cultivation: 11 amino acids, 6 vitamins, hematin, guanosine, D-glucose, Mg(2+), and inorganic phosphate. These media allow precise studies of the metabolism and differentiation of this unusual eukaryote.
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Affiliation(s)
- C Fulton
- Department of Biology, Brandeis University, Waltham, MA 02254
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13
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Aguilar-Díaz H, Díaz-Gallardo M, Laclette JP, Carrero JC. In vitro induction of Entamoeba histolytica cyst-like structures from trophozoites. PLoS Negl Trop Dis 2010; 4:e607. [PMID: 20169067 PMCID: PMC2821915 DOI: 10.1371/journal.pntd.0000607] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2009] [Accepted: 12/29/2009] [Indexed: 11/18/2022] Open
Abstract
Inhibition of encystment can be conceived as a potentially useful mechanism to block the transmission of Entamoeba histolytica under natural conditions. Unfortunately, amoeba encystment has not been achieved in vitro and drugs inhibiting the formation of cysts are not available. Luminal conditions inducing encystment in vivo are also unknown, but cellular stress such as exposure to reactive oxygen species from immune cells or intestinal microbiota could be involved. A role for certain divalent cations as cofactors of enzymes involved in excystment has also been described. In this study, we show that trophozoite cultures, treated with hydrogen peroxide in the presence of trace amounts of several cations, transform into small-sized spherical and refringent structures that exhibit resistance to different detergents. Ultrastructural analysis under scanning and transmission electron microscopy revealed multinucleated structures (some with four nuclei) with smooth, thick membranes and multiple vacuoles. Staining with calcofluor white, as well as an ELISA binding assay using wheat germ agglutinin, demonstrated the presence of polymers of N-acetylglucosamine (chitin), which is the primary component of the natural cyst walls. Over-expression of glucosamine 6-phosphate isomerase, likely to be the rate-limiting enzyme in the chitin synthesis pathway, was also confirmed by RT-PCR. These results suggest that E. histolytica trophozoites activated encystment pathways when exposed to our treatment.
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Affiliation(s)
- Hugo Aguilar-Díaz
- Department of Immunology, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad de México, México
| | - Martha Díaz-Gallardo
- Department of Developmental Genetics and Molecular Physiology, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Morelos, México
| | - Juan P. Laclette
- Department of Immunology, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad de México, México
- * E-mail: (JPL); (JCC)
| | - Julio C. Carrero
- Department of Immunology, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad de México, México
- * E-mail: (JPL); (JCC)
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14
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Disinfection Efficacy and Encystment Rate of Soft Contact Lens Multipurpose Solutions Against Acanthamoeba. Eye Contact Lens 2010; 36:26-32. [DOI: 10.1097/icl.0b013e3181c6e184] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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LEDEE DOLENAR, BYERS THOMASJ. Length and Sequence Heterogeneity in the Mitochondrial Internal Transcribed Spacer ofAcanthamoebaspp. J Eukaryot Microbiol 2009; 56:257-62. [DOI: 10.1111/j.1550-7408.2009.00400.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Resistance of Acanthamoeba cysts to disinfection in multiple contact lens solutions. J Clin Microbiol 2009; 47:2040-5. [PMID: 19403771 DOI: 10.1128/jcm.00575-09] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Acanthamoebae are free-living amoebae found in the environment, including soil, freshwater, brackish water, seawater, hot tubs, and Jacuzzis. Acanthamoeba species can cause keratitis, a painful vision-threatening infection of the cornea, and fatal granulomatous encephalitis in humans. More than 20 species of Acanthamoeba belonging to morphological groups I, II, and III distributed in 15 genotypes have been described. Among these, Acanthamoeba castellanii, A. polyphaga, and A. hatchetti are frequently identified as causing Acanthamoeba keratitis (AK). Improper contact lens care and contact with nonsterile water while wearing contact lenses are known risk factors for AK. During a recent multistate outbreak, AK was found to be associated with the use of Advanced Medical Optics Complete MoisturePlus multipurpose contact lens solution, which was hypothesized to have had insufficient anti-Acanthamoeba activity. As part of the investigation of that outbreak, we compared the efficacies of 11 different contact lens solutions against cysts of A. castellanii, A. polyphaga, and A. hatchetti (the isolates of all species were genotype T4), which were isolated in 2007 from specimens obtained during the outbreak investigation. The data, generated with A. castellanii, A. polyphaga, and A. hatchetti cysts, suggest that the two contact lens solutions containing hydrogen peroxide were the only solutions that showed any disinfection ability, with 0% and 66% growth, respectively, being detected with A. castellanii and 0% and 33% growth, respectively, being detected with A. polyphaga. There was no statistically significant difference in disinfection efficacy between the 11 solutions for A. hatchetti.
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GICQUAUD CLAUDE, TREMBLAY NADINE. Observations with Hoechst Staining of Amitosis inAcanthamoeba castellanii. ACTA ACUST UNITED AC 2007. [DOI: 10.1111/j.1550-7408.1991.tb04432.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Rocha-Azevedo BD, Menezes GC, Silva-Filho FCE. The interaction between Acanthamoeba polyphaga and human osteoblastic cells in vitro. Microb Pathog 2005; 40:8-14. [PMID: 16325369 DOI: 10.1016/j.micpath.2005.09.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2005] [Revised: 09/20/2005] [Accepted: 09/29/2005] [Indexed: 10/25/2022]
Abstract
Acanthamoeba spp. contains a group of free-living amoebae widespread in nature. These microorganisms may cause several diseases in humans including osteomyelitis. Here we characterize the cellular interaction between clinical and freshwater isolates of A. polyphaga with human osteoblasts. Amoeba cytoadherence was evaluated quantitatively and qualitatively. We observed that the clinical isolate readily adheres to human osteoblastic cells (HOB) in a saturable and time-dependent fashion. The cytoadhesion appears to be in part dependent on mannose-associated surface glycoconjugates, since prior incubation of the amoebae with alpha-mannose reduced cytoadhesion approximately 75%. Scanning electron microscopy revealed various amoebae exhibiting acanthapodia contacting the surface of osteoblasts. Some osteoblasts developed morphologies resembling apoptotic cells. The clinical isolate was highly toxic to HOB cells during 24 h of cell-protozoan interaction. Cytotoxicity was also dependent on the amoeba-cell ratio. During the cytopathogenic process we observed amoebae in the apparent process of ingestion of target cells and also amoebae extending projections or digipodia into osteoblast targets. The results indicate that A. polyphaga trophozoites attach and destroy human osteoblasts.
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Affiliation(s)
- Bruno da Rocha-Azevedo
- Programa de Bioengenharia e Biotecnologia Animal, Laboratório de Biologia da Superfície Celular, UFRJ, Instituto de Biofísica Carlos Chagas Filho, Rio de Janeiro, RJ, Brazil
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Booton GC, Rogerson A, Bonilla TD, Seal DV, Kelly DJ, Beattie TK, Tomlinson A, Lares-Villa F, Fuerst PA, Byers TJ. Molecular and physiological evaluation of subtropical environmental isolates of Acanthamoeba spp., causal agent of Acanthamoeba keratitis. J Eukaryot Microbiol 2004; 51:192-200. [PMID: 15134255 DOI: 10.1111/j.1550-7408.2004.tb00545.x] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Previous molecular examination of Acanthamoeba spp. has resulted in the determination of distinct genotypes in this genus (designated T1-T12, T14). Genotype T4 has been responsible for the majority of cases of Acanthamoeba keratitis. Here we examine the relative abundance of environmental T4 isolates on beaches and ask whether they have temperature and salinity tolerances that could enhance pathogenicity. Twenty-four Acanthamoeba strains were isolated from beach sand (n = 20), soil (n = 3), and tap water (n = 1) in south Florida. Phylogenetic analysis identified 19 of 24 isolates as T4, the Acanthamoeba keratitis-associated genotype. The remaining isolates were genotype T5 (4) and T11 (1). Nearly all beach isolates were genotype T4, whereas the tap water and soil isolates were mostly T5. All amoebae grew at 0, 1.0, and 2.0% salt and 19 of 20 beach isolates also grew at 3.2%. No soil or tap-water acanthamoebae reproduced at 3.2%. All isolates grew at 37 degrees C and two (T5) at 42 degrees C. Little correlation existed between beach location, salt-tolerance, and genetic relatedness. Overall, the large majority of environmental isolates obtained were genotype T4, suggesting it may be the most common genotype in this environment and could be a potential source of Acanthamoeba keratitis infections.
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Affiliation(s)
- Gregory C Booton
- Department of Molecular Genetics, The Ohio State University, Columbus, Ohio 43210, USA.
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20
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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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21
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Seal DV. Acanthamoeba keratitis update—incidence, molecular epidemiology and new drugs for treatment. Eye (Lond) 2003; 17:893-905. [PMID: 14631394 DOI: 10.1038/sj.eye.6700563] [Citation(s) in RCA: 142] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
A reliable figure for the expected incidence of Acanthamoeba keratitis of one per 30000 contact lens wearers per year has now been obtained from a combination of three cohort and three Questionnaire Reporting Surveys; 88% of cases wore hydrogel lenses and 12% wore rigid lenses. This figure now provides a basis for the expected number of cases against which to judge either epidemic outbreaks or effects of prevention with disinfecting solutions, better hygiene, or the use of disposable lenses. Molecular biology of Acanthamoeba has advanced considerably in the last 10 years with new automated sequencing technology. This has allowed the construction of a genotype identification scheme with 13 different genotypes against which to compare clinical isolates for epidemiological investigations or pathogenicity markers. So far, only four genotypes have been associated with keratitis of which the majority have been T4 but T3, T6, and T11 have each caused individual cases. Each genotype is heterogenous and can be further subdivided by comparison of sequences of diagnostic fragments of 18S rDNA, riboprinting by PCR-RFLP of 18S rDNA, or by mitochondrial DNA RFLP. Drug therapy has been revolutionised with the introduction of the biguanides-chlorhexidine or polyhexamethylene biguanide-with most but not all infections quickly resolving. Failure can still occur occasionally and further research is needed on more effective combination chemotherapy. A number of guanidines have been identified in this paper that could be usefully pursued as part of combination chemotherapy along with the alkylphosphocholines.
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Affiliation(s)
- D V Seal
- Applied Vision Research Centre, City University, London EC1, UK.
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22
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Abstract
Acanthamoeba spp. are free-living amebae that inhabit a variety of air, soil, and water environments. However, these amebae can also act as opportunistic as well as nonopportunistic pathogens. They are the causative agents of granulomatous amebic encephalitis and amebic keratitis and have been associated with cutaneous lesions and sinusitis. Immuno compromised individuals, including AIDS patients, are particularly susceptible to infections with Acanthamoeba. The immune defense mechanisms that operate against Acanthamoeba have not been well characterized, but it has been proposed that both innate and acquired immunity play a role. The ameba's life cycle includes an active feeding trophozoite stage and a dormant cyst stage. Trophozoites feed on bacteria, yeast, and algae. However, both trophozoites and cysts can retain viable bacteria and may serve as reservoirs for bacteria with human pathogenic potential. Diagnosis of infection includes direct microscopy of wet mounts of cerebrospinal fluid or stained smears of cerebrospinal fluid sediment, light or electron microscopy of tissues, in vitro cultivation of Acanthamoeba, and histological assessment of frozen or paraffin-embedded sections of brain or cutaneous lesion biopsy material. Immunocytochemistry, chemifluorescent dye staining, PCR, and analysis of DNA sequence variation also have been employed for laboratory diagnosis. Treatment of Acanthamoeba infections has met with mixed results. However, chlorhexidine gluconate, alone or in combination with propamidene isethionate, is effective in some patients. Furthermore, effective treatment is complicated since patients may present with underlying disease and Acanthamoeba infection may not be recognized. Since an increase in the number of cases of Acanthamoeba infections has occurred worldwide, these protozoa have become increasingly important as agents of human disease.
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Affiliation(s)
- Francine Marciano-Cabral
- Department of Microbiology and Immunology, Virginia Commonwealth University, Richmond, Virginia 23298-0678, USA.
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Abstract
Free-living amebas are widely distributed in soil and water, particularly members of the genera Acanthamoeba and NAEGLERIA: Since the early 1960s, they have been recognized as opportunistic human pathogens, capable of causing infections of the central nervous system (CNS) in both immunocompetent and immunocompromised hosts. Naegleria is the causal agent of a fulminant CNS condition, primary amebic meningoencephalitis; Acanthamoeba is responsible for a more chronic and insidious infection of the CNS termed granulomatous amebic encephalitis, as well as amebic keratitis. Balamuthia sp. has been recognized in the past decade as another ameba implicated in CNS infections. Cultivation of these organisms in vitro provides the basis for a better understanding of the biology of these amebas, as well as an important means of isolating and identifying them from clinical samples. Naegleria and Acanthamoeba can be cultured axenically in cell-free media or on tissue culture cells as feeder layers and in cultures with bacteria as a food source. Balamuthia, which has yet to be isolated from the environment, will not grow on bacteria. Instead, it requires tissue culture cells as feeder layers or an enriched cell-free medium. The recent identification of another ameba, Sappinia diploidea, suggests that other free-living forms may also be involved as causal agents of human infections.
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Affiliation(s)
- Frederick L Schuster
- Viral and Rickettsial Disease Laboratory, State of California Department of Health Services, Richmond, California 94804, USA.
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Schroeder JM, Booton GC, Hay J, Niszl IA, Seal DV, Markus MB, Fuerst PA, Byers TJ. Use of subgenic 18S ribosomal DNA PCR and sequencing for genus and genotype identification of acanthamoebae from humans with keratitis and from sewage sludge. J Clin Microbiol 2001; 39:1903-11. [PMID: 11326011 PMCID: PMC88046 DOI: 10.1128/jcm.39.5.1903-1911.2001] [Citation(s) in RCA: 398] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
This study identified subgenic PCR amplimers from 18S rDNA that were (i) highly specific for the genus Acanthamoeba, (ii) obtainable from all known genotypes, and (iii) useful for identification of individual genotypes. A 423- to 551-bp Acanthamoeba-specific amplimer ASA.S1 obtained with primers JDP1 and JDP2 was the most reliable for purposes i and ii. A variable region within this amplimer also identified genotype clusters, but purpose iii was best achieved with sequencing of the genotype-specific amplimer GTSA.B1. Because this amplimer could be obtained from any eukaryote, axenic Acanthamoeba cultures were required for its study. GTSA.B1, produced with primers CRN5 and 1137, extended between reference bp 1 and 1475. Genotypic identification relied on three segments: bp 178 to 355, 705 to 926, and 1175 to 1379. ASA.S1 was obtained from single amoeba, from cultures of all known 18S rDNA genotypes, and from corneal scrapings of Scottish patients with suspected Acanthamoeba keratitis (AK). The AK PCR findings were consistent with culture results for 11 of 15 culture-positive specimens and detected Acanthamoeba in one of nine culture-negative specimens. ASA.S1 sequences were examined for 6 of the 11 culture-positive isolates and were most closely associated with genotypic cluster T3-T4-T11. A similar distance analysis using GTSA.B1 sequences identified nine South African AK-associated isolates as genotype T4 and three isolates from sewage sludge as genotype T5. Our results demonstrate the usefulness of 18S ribosomal DNA PCR amplimers ASA.S1 and GTSA.B1 for Acanthamoeba-specific detection and reliable genotyping, respectively, and provide further evidence that T4 is the predominant genotype in AK.
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Affiliation(s)
- J M Schroeder
- Department of Molecular Genetics, The Ohio State University, 484 W. 12th Ave., Columbus, OH 43210, USA
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Stothard DR, Hay J, Schroeder-Diedrich JM, Seal DV, Byers TJ. Fluorescent oligonucleotide probes for clinical and environmental detection of Acanthamoeba and the T4 18S rRNA gene sequence type. J Clin Microbiol 1999; 37:2687-93. [PMID: 10405422 PMCID: PMC85314 DOI: 10.1128/jcm.37.8.2687-2693.1999] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/1998] [Accepted: 04/28/1999] [Indexed: 11/20/2022] Open
Abstract
The first genus- and subgenus-specific fluorescent oligonucleotide probes for in situ staining of Acanthamoeba are described. Sequences of these phylogeny-based probes complement the 18S rRNA and the gene encoding it (18S rDNA). The genus-specific probe (GSP) is a fluorescein-labeled 22-mer specific for Acanthamoeba as shown here by its hybridization to growing trophozoites of all 12 known Acanthamoeba 18S rDNA sequence types and by its failure to hybridize with amoebae of two other genera (Hartmannella vermiformis and Balamuthia mandrillaris), two human cell lines, and two bacteria (Pseudomonas aeruginosa and Escherichia coli). The sequence type T4-specific probe (ST4P) is a rhodamine-labeled 30-mer specific for Acanthamoeba 18S rDNA sequence type T4, as shown here in hybridization tests with trophozoites of all 12 sequence types. T4 is the subgenus group associated most closely with Acanthamoeba keratitis (AK). GSP also was tested with corneal scrapings from 17 patients with a high index of clinical suspicion of AK plus 5 patient controls. GSP stained both trophozoites and cysts, although nonspecific cyst wall autofluorescence also was observed. Results could be obtained with GSP in 1 to 2 days, and based on results from cell culture tests, the probe correctly detected the presence or absence of Acanthamoeba in 21 of 24 specimens from the 22 patients. The use of GSP with cultured trophozoites and cysts from corneal scrapings has illustrated the suitability of using fluorescent oligonucleotide probes for identification of the genus Acanthamoeba in both environmental and clinical samples. In addition, the use of ST4P with cultured amoebae has indicated the potential of oligonucleotide probes for use in subgenus classification.
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Affiliation(s)
- D R Stothard
- Department of Molecular Genetics, The Ohio State University, Columbus, Ohio 43210, USA
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26
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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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Stothard DR, Schroeder-Diedrich JM, Awwad MH, Gast RJ, Ledee DR, Rodriguez-Zaragoza S, Dean CL, Fuerst PA, Byers TJ. The evolutionary history of the genus Acanthamoeba and the identification of eight new 18S rRNA gene sequence types. J Eukaryot Microbiol 1998; 45:45-54. [PMID: 9495032 PMCID: PMC7194170 DOI: 10.1111/j.1550-7408.1998.tb05068.x] [Citation(s) in RCA: 257] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The 18S rRNA gene (Rns) phylogeny of Acanthamoeba is being investigated as a basis for improvements in the nomenclature and taxonomy of the genus. We previously analyzed Rns sequences from 18 isolates from morphological groups 2 and 3 and found that they fell into four distinct evolutionary lineages we called sequence types T1-T4. Here, we analyzed sequences from 53 isolates representing 16 species and including 35 new strains. Eight additional lineages (sequence types T5-T12) were identified. Four of the 12 sequence types included strains from more than one nominal species. Thus, sequence types could be equated with species in some cases or with complexes of closely related species in others. The largest complex, sequence type T4, which contained six closely related nominal species, included 24 of 25 keratitis isolates. Rns sequence variation was insufficient for full phylogenetic resolution of branching orders within this complex, but the mixing of species observed at terminal nodes confirmed that traditional classification of isolates has been inconsistent. One solution to this problem would be to equate sequence types and single species. Alternatively, additional molecular information will be required to reliably differentiate species within the complexes. Three sequence types of morphological group 1 species represented the earliest divergence in the history of the genus and, based on their genetic distinctiveness, are candidates for reclassification as one or more novel genera.
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Affiliation(s)
- D R Stothard
- Department of Molecular Genetics, Ohio State University, Columbus 43210-1292, USA
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28
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Gast RJ, Ledee DR, Fuerst PA, Byers TJ. Subgenus systematics of Acanthamoeba: four nuclear 18S rDNA sequence types. J Eukaryot Microbiol 1996; 43:498-504. [PMID: 8976608 DOI: 10.1111/j.1550-7408.1996.tb04510.x] [Citation(s) in RCA: 136] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Classification of Acanthamoeba at the subgenus level has been problematic, but increasing reports of Acanthamoeba as an opportunistic human pathogen have generated an interest in finding a more consistent basis for classification. Thus, we are developing a classification scheme based on RNA gene sequences. This first report is based on analysis of complete sequences of nuclear small ribosomal subunit RNA genes (Rns) from 18 strains. Sequence variation was localized in 12 highly variable regions. Four distinct sequence types were identified based on parsimony and distance analyses. Three were obtained from single strains: Type T1 from Acanthamoeba castellanii V006, T2 from Acanthamoeba palestinensis Reich, and T3 from Acanthamoeba griffini S-7. T4, the fourth sequence type, included 15 isolates classified as A. castellanii, Acanthamoeba polyphaga, Acanthamoeba rhysodes or Acanthamoeba sp., and included all 10 Acanthamoeba keratitis isolates. Interstrain sequence differences within T4 were 0%-4.3%, whereas differences among sequence types were 6%-12%. Branching orders obtained by parsimony and distance analyses were inconsistent with the current classification of T4 strains and provided further evidence of a need to reevaluate criteria for classification in this genus. Based on this report and others in preparation, we propose that Rns sequence types provide the consistent quantititive basis for classification that is needed.
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Affiliation(s)
- R J Gast
- Department of Molecular Genetics, Ohio State University, Columbus 43210-1292, USA
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Pyott A, Hay J, Seal D. Acanthamoeba keratitis: first recorded case from a Palestinian patient with trachoma. Br J Ophthalmol 1996; 80:849. [PMID: 8942385 PMCID: PMC505626 DOI: 10.1136/bjo.80.9.849] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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30
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Weekers PH, Wijen JP, Lomans BP, Vogels GD. Axenic mass cultivation of the free-living soil amoeba, Acanthamoeba castellanii in a laboratory fermentor. Antonie Van Leeuwenhoek 1996; 69:317-22. [PMID: 8836429 DOI: 10.1007/bf00399620] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Axenic mass cultivation of Acanthamoeba castellanii in laboratory fermentors (141) yielded after 20 days approximately 3 g cells (wet weight). After a short lag phase amoebal cell numbers increased exponentially to a maximum of 3.5 x 10(5) cells per ml until cell death occurred after 20 days. Optical density and protein concentrations revealed identical patterns. During amoebal growth only 12-19% of the initially added glucose (100 mM) as sole carbon source was used. Large amounts of ammonia (1 g in 10.51 culture volume) were excreted into the medium which subsequently raised the pH from 6.6 to 7.7, and from 6.6 to 6.8 in 2 and 20 mM buffered media, respectively. Growth inhibition and cell death could not be explained by a depletion of glucose or oxygen limitations during growth. The production of ammonia had a growth inhibitory effect, however, the sudden termination of the exponential growth phase and cell death could not be explained by the toxic influence of ammonia only.
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Affiliation(s)
- P H Weekers
- Department of Microbiology, Faculty of Science, University of Nijmegen, The Netherlands
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31
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Aitken D, Hay J, Kinnear FB, Kirkness CM, Lee WR, Seal DV. Amebic keratitis in a wearer of disposable contact lenses due to a mixed Vahlkampfia and Hartmannella infection. Ophthalmology 1996; 103:485-94. [PMID: 8600427 DOI: 10.1016/s0161-6420(96)30667-2] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
PURPOSE To support the hypothesis that Acanthamoeba is not a unique cause of amebic keratitis, we report a case of amebic keratitis in which viable Acanthamoeba could not be isolated from corneal tissue. Vahlkampfia and Hartmannella, two other genera of free-living ameba, were isolated, however, using prolonged culture. METHODS A 24-year-old wearer of soft contact lenses had keratitis. Extensive histologic and microbiologic investigations were performed on corneal scrape, biopsy, and keratoplasty tissue. Contact lenses, storage case, and the home water supply, where contact lens hygiene was practiced, were examined for the presence of micro-organisms. RESULTS No viruses, pathogenic bacteria, or fungi were detected from corneal tissue samples. Amebae were observed using light and electron microscopy, but these could not be unequivocally classified using immunocytochemical staining. Viable Vahlkampfia and Hartmannella, but no Acanthamoeba, were isolated from the corneal biopsy sample. Indirect immunofluorescence with a range of polyclonal rabbit antisera raised against axenically cultivated stains of the three amebal genera was unhelpful because of cross-reactivity. A diverse range of micro-organisms was present within the storage case, including the three amebal species. Amebic cysts also were associated with the contact lens. CONCLUSION A mixed non-Acanthamoeba amebic keratitis has been identified in a wearer of soft contact lenses where lack of storage case hygiene provided the opportunity for the free-living protozoa Vahlkampfia and Hartmannella to be introduced to the ocular surface. When Acanthamoeba-like keratitis occurs, but where Acanthamoeba cannot be isolated using conventional laboratory culture methods, alternate means should be used to identify other amebae that may be present. Polyclonal immunofluorescent antibody staining was unreliable for generic identification of pathogenic free-living amebae in corneal tissue.
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Affiliation(s)
- D Aitken
- Department of Ophthalmology, University of Glasgow, Scotland
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Affiliation(s)
- R J Gast
- Department of Molecular Genetics, Ohio State University, Columbus 43210-1292, USA
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Hay J, Seal DV, Connor R, Simmons PA, Tomlinson A. Disinfection and sonication: Effect on association of Acanthamoeba cysts with an ionic, high-water content hydrogel contact lens. ACTA ACUST UNITED AC 1995. [DOI: 10.1016/s0141-7037(95)80042-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Hay J, Seal DV, Billcliffe B, Freer JH. Non-culturable Legionella pneumophila associated with Acanthamoeba castellanii: detection of the bacterium using DNA amplification and hybridization. THE JOURNAL OF APPLIED BACTERIOLOGY 1995; 78:61-5. [PMID: 7883646 DOI: 10.1111/j.1365-2672.1995.tb01674.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The intracellular localization of Legionella pneumophila serogroup 1 within Acanthamoeba castellanii rendered the bacteria non-culturable on supplemented BCYE agar. DNA amplification, using two 19-mer primers, and hybridization using a 25-mer oligonucleotide probe, permitted detection of Leg. pneumophila in approximately 81% (29/36) of samples where the bacteria could not be detected using culture. A combination of co-cultivation of samples with Leg. pneumophila-naive A. polyphaga or Hartmannella vermiformis, incubation in a defined liquid medium or use of catalase indicated that approximately 31% (9/29) of the samples contained Leg. pneumophila which were viable although not culturable.
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Affiliation(s)
- J Hay
- Department of Ophthalmology, University of Glasgow, UK
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35
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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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Gast RJ, Fuerst PA, Byers TJ. Discovery of group I introns in the nuclear small subunit ribosomal RNA genes of Acanthamoeba. Nucleic Acids Res 1994; 22:592-6. [PMID: 8127708 PMCID: PMC307848 DOI: 10.1093/nar/22.4.592] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
The discovery of group I introns in small subunit nuclear rDNA (nsrDNA) is becoming more common as the effort to generate phylogenies based upon nsrDNA sequences grows. In this paper we describe the discovery of the first two group I introns in the nsrDNA from the genus Acanthamoeba. The introns are in different locations in the genes, and have no significant primary sequence similarity to each other. They are identified as group I introns by the conserved P, Q, R and S sequences (1), and the ability to fit the sequences to a consensus secondary structure model for the group I introns (1, 2). Both introns are absent from the mature srRNA. A BLAST search (3) of nucleic acid sequences present in GenBank and EMBL revealed that the A. griffini intron was most similar to the nsrDNA group I intron of the green alga Dunaliella parva. A similar search found that the A. lenticulata intron was not similar to any of the other reported group I introns.
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Affiliation(s)
- R J Gast
- Department of Molecular Genetics, Ohio State University, Columbus 43210-1292
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Weekers PH, Vogels GD. Axenic cultivation of the free-living amoebae, Acanthamoeba castellanii and Hartmannella vermiformis in a chemostat. J Microbiol Methods 1994. [DOI: 10.1016/0167-7012(94)90021-3] [Citation(s) in RCA: 3] [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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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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Shukla OP, Kaul SM, Mehlotra RK. Nutritional studies on Acanthamoeba culbertsoni and development of chemically defined medium. THE JOURNAL OF PROTOZOOLOGY 1990; 37:237-42. [PMID: 2359051 DOI: 10.1111/j.1550-7408.1990.tb01134.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
A chemically defined medium containing 11 amino acids, 3 vitamins, 6 inorganic salts and glucose, yielding maximum cell densities of 1.5-2.5 x 10(7) cells/ml, has been developed for Acanthamoeba culbertsoni with a mean generation time (MGT) of 10 h. A medium containing six amino acids viz. arginine, methionine, leucine, isoleucine, valine and glycine along with other components could also support good albeit slower growth (MGT 27 h) of the amoeba. Acetate did not serve as a suitable carbon/energy source for A. culbertsoni. This organism bears close resemblance in its nutritional requirements to other Acanthamoeba especially A. polyphaga.
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Affiliation(s)
- O P Shukla
- Division of Biochemistry, Central Drug Research Institute, Lucknow, India
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40
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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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42
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Poulin R, Larochelle J, Hellebust JA. The regulation of amino acid metabolism during hyperosmotic stress inAcanthamoeba castellanii. ACTA ACUST UNITED AC 1987. [DOI: 10.1002/jez.1402430303] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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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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Jantzen H, Schulze I. Effect of essential amino acids on the phosphorylation of a 40S ribosomal protein and protein synthesis in Acanthamoeba castellanii. J Cell Physiol 1987; 130:444-52. [PMID: 3558495 DOI: 10.1002/jcp.1041300319] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Reversible and multiple phosphorylation of a 40S ribosomal protein is observed in a variety of eukaryotic cells. In the primitive eukaryote Acanthamoeba, one or three phosphorylated S3 derivatives are observed during growth phase in nondefined nutrient medium (ND cells) or in chemically defined nutrient medium (D cells), respectively. In both cases, stationary phase cells exhibit nonphosphorylated S3; however, transfer of these cells into the respective fresh nutrient media results in a transient accumulation of four phosphorylated S3 derivatives. Transfer of D cells into nutrient medium, deficient in all or any single essential amino acids, leads to reversible inhibition of S3 phosphorylation and growth arrest. The low level of phosphorylated S3 is not simply the consequence of growth arrest, since in cells where growth is arrested differently, the level of phosphorylated S3 can be high. In response to amino acid deficiency, a number of other changes can be observed. These include a 2-3-fold decrease of total protein synthesis, 13 changes in the cellular protein pattern, and specific alterations in the ribosome absorbance profiles and in the distribution of poly-A+ RNA within subribosomal and ribosomal fractions. While the rate of total protein synthesis seems to be associated with the level of phosphorylated S3, the level of the synthesis of at least 10 of the particular proteins can be dissociated from the level of S3 phosphorylation.
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Poulin R, Larochelle J, Nadeau P. Polyamines in Acanthamoeba castellanii: presence of an unusually high, osmotically sensitive pool of 1,3-diaminopropane. Biochem Biophys Res Commun 1984; 122:388-93. [PMID: 6743339 DOI: 10.1016/0006-291x(84)90487-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
High (15-25 mM) concentrations of 1,3-diaminopropane, a normally minor derivative of polyamine metabolism, have been observed in vegetative cells of Acanthamoeba castellanii. Trace amounts of a putative polyamine, which chromatographically behaved like norspermidine, were also found. The size of the intracellular pool of 1,3-diaminopropane was inversely related to the ambient osmolality and to the free amino acid levels during osmotic shock experiments. Due to its high concentration in A. castellanii, this diamine may be operative in ionic regulation during environmental stress. 1,3-diaminopropane may substitute for putrescine, a common diamine which was undetectable in A. castellanii.
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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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Akins RA, Byers TJ. Differentiation promoting factors induced in Acanthamoeba by inhibitors of mitochondrial macromolecule synthesis. Dev Biol 1980; 78:126-40. [PMID: 7399137 DOI: 10.1016/0012-1606(80)90323-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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