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Rivera J, Valerdi-Negreros JC, Vázquez-Enciso DM, Argueta-Zepeda FS, Vinuesa P. Phylogenomic, structural, and cell biological analyses reveal that Stenotrophomonas maltophilia replicates in acidified Rab7A-positive vacuoles of Acanthamoeba castellanii. Microbiol Spectr 2024; 12:e0298823. [PMID: 38319117 PMCID: PMC10913462 DOI: 10.1128/spectrum.02988-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Accepted: 01/15/2024] [Indexed: 02/07/2024] Open
Abstract
Acanthamoeba species are clinically relevant free-living amoebae (FLA) ubiquitously found in soil and water bodies. Metabolically active trophozoites graze on diverse microbes via phagocytosis. However, functional studies on Rab GTPases (Rabs), which are critical for controlling vesicle trafficking and maturation, are scarce for this FLA. This knowledge gap can be partly explained by the limited genetic tools available for Acanthamoeba cell biology. Here, we developed plasmids to generate fusions of A. castellanii strain Neff proteins to the N- or C-termini of mEGFP and mCherry2. Phylogenomic and structural analyses of the 11 Neff Rab7 paralogs found in the RefSeq assembly revealed that eight of them had non-canonical sequences. After correcting the gene annotation for the Rab7A ortholog, we generated a line stably expressing an mEGFP-Rab7A fusion, demonstrating its correct localization to acidified macropinocytic and phagocytic vacuoles using fluorescence microscopy live cell imaging (LCI). Direct labeling of live Stenotrophomonas maltophilia ESTM1D_MKCAZ16_6a (Sm18) cells with pHrodo Red, a pH-sensitive dye, demonstrated that they reside within acidified, Rab7A-positive vacuoles. We constructed new mini-Tn7 delivery plasmids and tagged Sm18 with constitutively expressed mScarlet-I. Co-culture experiments of Neff trophozoites with Sm18::mTn7TC1_Pc_mScarlet-I, coupled with LCI and microplate reader assays, demonstrated that Sm18 underwent multiple replication rounds before reaching the extracellular medium via non-lytic exocytosis. We conclude that S. maltophilia belongs to the class of bacteria that can use amoeba as an intracellular replication niche within a Stenotrophomonas-containing vacuole that interacts extensively with the endocytic pathway.IMPORTANCEDiverse Acanthamoeba lineages (genotypes) are of increasing clinical concern, mainly causing amoebic keratitis and granulomatous amebic encephalitis among other infections. S. maltophilia ranks among the top 10 most prevalent multidrug-resistant opportunistic nosocomial pathogens and is a recurrent member of the microbiome hosted by Acanthamoeba and other free-living amoebae. However, little is known about the molecular strategies deployed by Stenotrophomonas for an intracellular lifestyle in amoebae and other professional phagocytes such as macrophages, which allow the bacterium to evade the immune system and the action of antibiotics. Our plasmids and easy-to-use microtiter plate co-culture assays should facilitate investigations into the cellular microbiology of Acanthamoeba interactions with Stenotrophomonas and other opportunistic pathogens, which may ultimately lead to the discovery of new molecular targets and antimicrobial therapies to combat difficult-to-treat infections caused by these ubiquitous microbes.
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Affiliation(s)
- Javier Rivera
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México (UNAM), Cuernavaca, Morelos, Mexico
| | - Julio C. Valerdi-Negreros
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México (UNAM), Cuernavaca, Morelos, Mexico
- Programa de Doctorado en Ciencias Biomédicas, UNAM, Mexico City, Mexico
| | - Diana M. Vázquez-Enciso
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México (UNAM), Cuernavaca, Morelos, Mexico
- Programa de Maestría y Doctorado en Ciencias Bioquímicas, UNAM, Mexico City, Mexico
| | - Fulvia-Stefany Argueta-Zepeda
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México (UNAM), Cuernavaca, Morelos, Mexico
- Programa de Maestría y Doctorado en Ciencias Bioquímicas, UNAM, Mexico City, Mexico
| | - Pablo Vinuesa
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México (UNAM), Cuernavaca, Morelos, Mexico
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Ferreira MDS, Gonçalves DDS, Mendoza SR, de Oliveira GA, Pontes B, la Noval CRD, Honorato L, Ramos LFC, Nogueira FCS, Domont GB, Casadevall A, Nimrichter L, Peralta JM, Guimaraes AJ. β-1,3-Glucan recognition by Acanthamoeba castellanii as a putative mechanism of amoeba-fungal interactions. Appl Environ Microbiol 2024; 90:e0173623. [PMID: 38259076 PMCID: PMC10880599 DOI: 10.1128/aem.01736-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Accepted: 12/15/2023] [Indexed: 01/24/2024] Open
Abstract
In this study, we conducted an in-depth analysis to characterize potential Acanthamoeba castellanii (Ac) proteins capable of recognizing fungal β-1,3-glucans. Ac specifically anchors curdlan or laminarin, indicating the presence of surface β-1,3-glucan-binding molecules. Using optical tweezers, strong adhesion of laminarin- or curdlan-coated beads to Ac was observed, highlighting their adhesive properties compared to controls (characteristic time τ of 46.9 and 43.9 s, respectively). Furthermore, Histoplasma capsulatum (Hc) G217B, possessing a β-1,3-glucan outer layer, showed significant adhesion to Ac compared to a Hc G186 strain with an α-1,3-glucan outer layer (τ of 5.3 s vs τ 83.6 s). The addition of soluble β-1,3-glucan substantially inhibited this adhesion, indicating the involvement of β-1,3-glucan recognition. Biotinylated β-1,3-glucan-binding proteins from Ac exhibited higher binding to Hc G217B, suggesting distinct recognition mechanisms for laminarin and curdlan, akin to macrophages. These observations hinted at the β-1,3-glucan recognition pathway's role in fungal entrance and survival within phagocytes, supported by decreased fungal viability upon laminarin or curdlan addition in both phagocytes. Proteomic analysis identified several Ac proteins capable of binding β-1,3-glucans, including those with lectin/glucanase superfamily domains, carbohydrate-binding domains, and glycosyl transferase and glycosyl hydrolase domains. Notably, some identified proteins were overexpressed upon curdlan/laminarin challenge and also demonstrated high affinity to β-1,3-glucans. These findings underscore the complexity of binding via β-1,3-glucan and suggest the existence of alternative fungal recognition pathways in Ac.IMPORTANCEAcanthamoeba castellanii (Ac) and macrophages both exhibit the remarkable ability to phagocytose various extracellular microorganisms in their respective environments. While substantial knowledge exists on this phenomenon for macrophages, the understanding of Ac's phagocytic mechanisms remains elusive. Recently, our group identified mannose-binding receptors on the surface of Ac that exhibit the capacity to bind/recognize fungi. However, the process was not entirely inhibited by soluble mannose, suggesting the possibility of other interactions. Herein, we describe the mechanism of β-1,3-glucan binding by A. castellanii and its role in fungal phagocytosis and survival within trophozoites, also using macrophages as a model for comparison, as they possess a well-established mechanism involving the Dectin-1 receptor for β-1,3-glucan recognition. These shed light on a potential parallel evolution of pathways involved in the recognition of fungal surface polysaccharides.
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Affiliation(s)
- Marina da Silva Ferreira
- Laboratório de Bioquímica e Imunologia das Micoses, Departamento de Microbiologia e Parasitologia, Instituto Biomédico, Universidade Federal Fluminense, Niterói, Rio de Janeiro, Brazil
- Programa de Pós-Graduação em Imunologia e Inflamação, Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Niterói, Rio de Janeiro, Brazil
| | - Diego de Souza Gonçalves
- Programa de Pós-Graduação em Doenças Infecciosas e Parasitárias, Faculdade de Medicina, Universidade Federal do Rio de Janeiro, Niterói, Rio de Janeiro, Brazil
| | - Susana Ruiz Mendoza
- Laboratório de Bioquímica e Imunologia das Micoses, Departamento de Microbiologia e Parasitologia, Instituto Biomédico, Universidade Federal Fluminense, Niterói, Rio de Janeiro, Brazil
- Programa de Pós-Graduação em Imunologia e Inflamação, Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Niterói, Rio de Janeiro, Brazil
| | - Gabriel Afonso de Oliveira
- Laboratório de Bioquímica e Imunologia das Micoses, Departamento de Microbiologia e Parasitologia, Instituto Biomédico, Universidade Federal Fluminense, Niterói, Rio de Janeiro, Brazil
| | - Bruno Pontes
- Instituto de Ciências Biomédicas e Centro Nacional de Biologia Estrutural e Bioimagem, Universidade Federal do Rio de Janeiro, Niterói, Rio de Janeiro, Brazil
| | - Claudia Rodríguez-de la Noval
- Laboratório de Bioquímica e Imunologia das Micoses, Departamento de Microbiologia e Parasitologia, Instituto Biomédico, Universidade Federal Fluminense, Niterói, Rio de Janeiro, Brazil
- Programa de Pós-Graduação em Doenças Infecciosas e Parasitárias, Faculdade de Medicina, Universidade Federal do Rio de Janeiro, Niterói, Rio de Janeiro, Brazil
| | - Leandro Honorato
- Laboratório de Glicobiologia de Eucariotos, Departamento de Microbiologia Geral, Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Niterói, Rio de Janeiro, Brazil
| | - Luis Felipe Costa Ramos
- Departamento de Bioquímica, Instituto de Química, Universidade Federal do Rio de Janeiro, Niterói, Rio de Janeiro, Brazil
| | - Fábio C. S. Nogueira
- Departamento de Bioquímica, Instituto de Química, Universidade Federal do Rio de Janeiro, Niterói, Rio de Janeiro, Brazil
| | - Gilberto B. Domont
- Departamento de Bioquímica, Instituto de Química, Universidade Federal do Rio de Janeiro, Niterói, Rio de Janeiro, Brazil
| | - Arturo Casadevall
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Leonardo Nimrichter
- Programa de Pós-Graduação em Imunologia e Inflamação, Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Niterói, Rio de Janeiro, Brazil
- Laboratório de Glicobiologia de Eucariotos, Departamento de Microbiologia Geral, Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Niterói, Rio de Janeiro, Brazil
- Rede Micologia RJ - Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ), Niterói, Rio de Janeiro, Brazil
| | - Jose Mauro Peralta
- Programa de Pós-Graduação em Doenças Infecciosas e Parasitárias, Faculdade de Medicina, Universidade Federal do Rio de Janeiro, Niterói, Rio de Janeiro, Brazil
| | - Allan J. Guimaraes
- Laboratório de Bioquímica e Imunologia das Micoses, Departamento de Microbiologia e Parasitologia, Instituto Biomédico, Universidade Federal Fluminense, Niterói, Rio de Janeiro, Brazil
- Programa de Pós-Graduação em Imunologia e Inflamação, Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Niterói, Rio de Janeiro, Brazil
- Rede Micologia RJ - Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ), Niterói, Rio de Janeiro, Brazil
- Pós-Graduação em Microbiologia e Parasitologia Aplicadas, Instituto Biomédico, Universidade Federal Fluminense, Niterói, Rio de Janeiro, Brazil
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de Oliveira EG, Filho CADC, Rodrigues RAL. An overview of viral chitinases: General properties and biotechnological potential. Exp Biol Med (Maywood) 2023; 248:2053-2061. [PMID: 38057942 PMCID: PMC10800131 DOI: 10.1177/15353702231208408] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/08/2023] Open
Abstract
Chitin is a biopolymer profusely present in nature and of pivotal importance as a structural component in cells. It is degraded by chitinases, enzymes naturally produced by different organisms. Chitinases are proteins enrolled in many cellular mechanisms, including the remodeling process of the fungal cell wall, the cell growth process, the autolysis of filamentous fungi, and cell separation of yeasts, among others. These enzymes also have properties with different biotechnological applications. They are used to produce polymers, for biological control, biofilm formation, and as antitumor and anti-inflammatory target molecules. Chitinases are classified into different glycoside hydrolase (GH) families and are widespread in microorganisms, including viruses. Among them, the GH18 family is highly predominant in the viral genomes, being present and active enzymes in baculoviruses and nucleocytoplasmic large DNA viruses (NCLDV), especially chloroviruses from the Phycodnaviridae family. These viral enzymes contain one or more GH domains and seem to be involved during the viral replication cycle. Curiously, only a few DNA viruses have these enzymes, and studying their properties could be a key feature for biological and biotechnological novelties. Here, we provide an overview of viral chitinases and their probable function in viral infection, showing evidence of at least two distinct origins for these enzymes. Finally, we discuss how these enzymes can be applied as biotechnological tools and what one can expect for the coming years on these GHs.
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Affiliation(s)
- Ellen Gonçalves de Oliveira
- Laboratório de Vírus, Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte 31270-901, Brazil
| | - Clécio Alonso da Costa Filho
- Laboratório de Vírus, Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte 31270-901, Brazil
| | - Rodrigo Araújo Lima Rodrigues
- Laboratório de Vírus, Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte 31270-901, Brazil
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SLAMF7/STAT6 Pathway Inhibits Innate Immune Response in Late-Stage Human Acanthamoeba Keratitis: A Comparative Transcriptome Analysis. Microorganisms 2023; 11:microorganisms11020365. [PMID: 36838330 PMCID: PMC9961001 DOI: 10.3390/microorganisms11020365] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Revised: 01/27/2023] [Accepted: 01/29/2023] [Indexed: 02/05/2023] Open
Abstract
Acanthamoeba keratitis (AK) is a blinding corneal infection caused by the protozoan Acanthamoeba. The long-term course of AK suggests the host immunity could not kill Acanthamoeba rapidly. The immune status is still unclear in the late stage of AK. The comparative transcriptome analysis was made based on the bulk RNA sequencing of cornea tissues from AK patients and donors. Differentially expressed genes and enriched signaling pathways were calculated. CIBERSORT algorithm was used for immune infiltration analysis of cornea tissue between AK and normal controls. A total of 2668 differentially expressed genes, including 1477 upregulated genes and 1191 downregulated genes, were detected. Gene Ontology analysis revealed that the pathways were significantly enriched in leukocyte migration, regulation of T-cell activation, the external side of plasma membrane, collagen-containing extracellular matrix, immune receptor activity, and cytokine binding. The Kyoto Encyclopedia of Genes and Genomes pathway analysis showed that the pathways were significantly enriched in the cytokine-cytokine receptor interaction, hematopoietic cell lineage, and Staphylococcus aureus infection pathway. The immune infiltration profiles varied little between AK and normal controls. Compared with normal tissue, cornea tissue of AK contained a higher proportion of M0 macrophages and CD8 T cells, while resting memory CD4 T cells contributed to a relatively lower portion (p < 0.05). Finally, the expression levels of cell markers and SLAMF7/STAT6 pathway were confirmed by histopathology examinations, RT-qPCR, and Western blot.
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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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Campolo A, Pifer R, Walters R, Thomas M, Miller E, Harris V, King J, Rice CA, Shannon P, Patterson B, Crary M. Acanthamoeba spp. aggregate and encyst on contact lens material increasing resistance to disinfection. Front Microbiol 2022; 13:1089092. [PMID: 36601401 PMCID: PMC9806144 DOI: 10.3389/fmicb.2022.1089092] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Accepted: 11/28/2022] [Indexed: 12/23/2022] Open
Abstract
Introduction Acanthamoeba keratitis is often caused when Acanthamoeba contaminate contact lenses and infect the cornea. Acanthamoeba is pervasive in the environment as a motile, foraging trophozoite or biocide-resistant and persistent cyst. As contact lens contamination is a potential first step in infection, we studied Acanthamoeba's behavior and interactions on different contact lens materials. We hypothesized that contact lenses may induce aggregation, which is a precursor to encystment, and that aggregated encystment would be more difficult to disinfect than motile trophozoites. Methods Six clinically and/or scientifically relevant strains of Acanthamoeba (ATCC 30010, ATCC 30461, ATCC 50370, ATCC 50702, ATCC 50703, and ATCC PRA-115) were investigated on seven different common silicone hydrogel contact lenses, and a no-lens control, for aggregation and encystment for 72 h. Cell count and size were used to determine aggregation, and fluorescent staining was used to understand encystment. RNA seq was performed to describe the genome of Acanthamoeba which was individually motile or aggregated on different lens materials. Disinfection efficacy using three common multi-purpose solutions was calculated to describe the potential disinfection resistance of trophozoites, individual cysts, or spheroids. Results Acanthamoeba trophozoites of all strains examined demonstrated significantly more aggregation on specific contact lens materials than others, or the no-lens control. Fluorescent staining demonstrated encystment in as little as 4 hours on contact lens materials, which is substantially faster than previously reported in natural or laboratory settings. Gene expression profiles corroborated encystment, with significantly differentially expressed pathways involving actin arrangement and membrane complexes. High disinfection resistance of cysts and spheroids with multi-purpose solutions was observed. Discussion Aggregation/encystment is a protective mechanism which may enable Acanthamoeba to be more disinfection resistant than individual trophozoites. This study demonstrates that some contact lens materials promote Acanthamoeba aggregation and encystment, and Acanthamoeba spheroids obstruct multi-purpose solutions from disinfecting Acanthamoeba.
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Affiliation(s)
| | - Reed Pifer
- Alcon Research, LLC, Fort Worth, TX, United States
| | | | - Megan Thomas
- Alcon Research, LLC, Fort Worth, TX, United States
| | - Elise Miller
- Alcon Research, LLC, Fort Worth, TX, United States
| | | | - Jamie King
- Alcon Research, LLC, Fort Worth, TX, United States
| | - Christopher A. Rice
- Department of Comparative Pathobiology, College of Veterinary Medicine, Purdue University, West Lafayette, IN, United States,Purdue Institute for Drug Discovery (PIDD), Purdue University, West Lafayette, IN, United States,Purdue Institute of Inflammation, Immunology and Infectious Disease (PI4D), Purdue University, West Lafayette, IN, United States
| | - Paul Shannon
- Alcon Research, LLC, Fort Worth, TX, United States
| | | | - Monica Crary
- Alcon Research, LLC, Fort Worth, TX, United States,*Correspondence: Monica Crary,
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Rased NM, Johari SATT, Zakeri HA, Ma NL, Razali SA, Hashim F. Combinatorial treatment with β-glucanase enzyme and chlorhexidine induces cysticidal effects in Acanthamoeba cyst. Parasitol Res 2022; 121:3105-3119. [DOI: 10.1007/s00436-022-07650-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2021] [Accepted: 08/29/2022] [Indexed: 11/24/2022]
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Fechtali-Moute Z, Loiseau PM, Pomel S. Stimulation of Acanthamoeba castellanii excystment by enzyme treatment and consequences on trophozoite growth. Front Cell Dev Biol 2022; 10:982897. [PMID: 36172275 PMCID: PMC9511172 DOI: 10.3389/fcell.2022.982897] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Accepted: 08/17/2022] [Indexed: 11/13/2022] Open
Abstract
Acanthamoeba castellanii is a widespread Free-Living Amoeba (FLA) that can cause severe ocular or cerebral infections in immunocompetent and immunocompromised patients, respectively, besides its capacity to transport diverse pathogens. During their life cycle, FLA can alternate between a vegetative form, called a trophozoite, and a latent and resistant form, called a cyst. This resistant form is characterized by the presence of a cell wall containing two layers, namely the ectocyst and the endocyst, mainly composed of cellulose and proteins. In the present work, we aimed to stimulate Acanthamoeba castellanii excystment by treating their cysts with a cellulolytic enzyme, i.e., cellulase, or two proteolytic enzymes, i.e., collagenase and pepsin. While 11 days were necessary to obtain total excystment in the control at 27°C, only 48 h were sufficient at the same temperature to obtain 100% trophozoites in the presence of 25 U/mL cellulase, 50 U/mL collagenase or 100 U/mL pepsin. Additionally, more than 96% amoebae have excysted after only 24 h with 7.5 U/mL cellulase at 30°C. Nevertheless, no effect of the three enzymes was observed on the excystment of Balamuthia mandrillaris and Vermamoeba vermiformis. Surprisingly, A. castellanii trophozoites excysted in the presence of cellulase displayed a markedly shorter doubling time at 7 h, in comparison to the control at 23 h. Likewise, trophozoites doubled their population in 9 h when both cellulose and cellulase were added to the medium, indicating that Acanthamoeba cyst wall degradation products promote their trophozoite proliferation. The analysis of cysts in epifluorescent microscopy using FITC-lectins and in electron microscopy revealed a disorganized endocyst and a reduction of the intercystic space area after cellulase treatment, implying that these cellular events are preliminary to trophozoite release during excystment. Further studies would be necessary to determine the signaling pathways involved during this amoebal differentiation process to identify new therapeutic targets for the development of anti-acanthamoebal drugs.
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A time-resolved multi-omics atlas of Acanthamoeba castellanii encystment. Nat Commun 2022; 13:4104. [PMID: 35835784 PMCID: PMC9283445 DOI: 10.1038/s41467-022-31832-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Accepted: 06/30/2022] [Indexed: 12/14/2022] Open
Abstract
Encystment is a common stress response of most protists, including free-living amoebae. Cyst formation protects the amoebae from eradication and can increase virulence of the bacteria they harbor. Here, we mapped the global molecular changes that occur in the facultatively pathogenic amoeba Acanthamoeba castellanii during the early steps of the poorly understood process of encystment. By performing transcriptomic, proteomic, and phosphoproteomic experiments during encystment, we identified more than 150,000 previously undescribed transcripts and thousands of protein sequences absent from the reference genome. These results provide molecular details to the regulation of expected biological processes, such as cell proliferation shutdown, and reveal new insights such as a rapid phospho-regulation of sites involved in cytoskeleton remodeling and translation regulation. This work constitutes the first time-resolved molecular atlas of an encysting organism and a useful resource for further investigation of amoebae encystment to allow for a better control of pathogenic amoebae.
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Mungroo MR, Khan NA, Maciver S, Siddiqui R. Opportunistic free-living amoebal pathogens. Pathog Glob Health 2021; 116:70-84. [PMID: 34602025 DOI: 10.1080/20477724.2021.1985892] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Abstract
Pathogenic free-living amoebae affecting the central nervous system are known to cause granulomatous amoebic encephalitis (GAE) or primary amoebic meningoencephalitis (PAM). Although hosts with impaired immunity are generally at a higher risk of severe disease, amoebae such as Naegleria fowleri and Balamuthia mandrillaris can instigate disease in otherwise immunocompetent individuals, whereas Acanthamoeba species mostly infect immunocompromised people. Acanthamoeba also cause a sight-threatening eye infection, mostly in contact lens wearers. Although infections due to pathogenic amoebae are considered rare, recently, these deadly amoebae were detected in water supplies in the USA. This is of particular concern, especially with global warming further exacerbating the problem. Herein, we describe the epidemiology, presentation, diagnosis, and management of free-living amoeba infections.
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Affiliation(s)
- Mohammad Ridwane Mungroo
- Department of Clinical Sciences, College of Medicine, University City, Sharjah, United Arab Emirates
| | - Naveed Ahmed Khan
- Department of Clinical Sciences, College of Medicine, University City, Sharjah, United Arab Emirates.,Research Institute of Health and Medical Sciences, University of Sharjah, Sharjah, UAE
| | - Sutherland Maciver
- Centre for Discovery Brain Sciences, Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, UK
| | - Ruqaiyyah Siddiqui
- College of Arts and Sciences, American University of Sharjah, Sharjah, UAE
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Inhibitory effect of host ocular microenvironmental factors on chlorhexidine digluconate activity. Antimicrob Agents Chemother 2021; 65:AAC.02066-20. [PMID: 33685899 PMCID: PMC8092908 DOI: 10.1128/aac.02066-20] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Acanthamoeba spp. are free-living protozoan that cause a serious human eye disease called Acanthamoeba keratitis (AK). Several new and effective medical therapy for AK patients remains highly debated and therefore, CHG is still considered one of the first lines of treatment for AK patients. We hypothesized that ocular microenvironmental factors are responsible for Acanthamoeba drug resistance and clinical AK treatment failure. To investigate the influence of the ocular surface on CHG treatment, we tested the effect of several ocular elements on the anti-amoeba activity of CHG. The suspected inhibitory elements, including mucin, albumin, human and amoeba cell lysates, live and heat-killed bacteria, and cornea, were added to the amoebicidal activity platform, where amoeba was incubated with CHG at varying concentrations. Mucin showed a significant inhibitory effect on CHG activity against Acanthamoeba castellanii In contrast, albumin did not affect CHG treatment. Furthermore, human and amoeba cell lysates as well as live and heat-killed bacterial suspensions also significantly inhibited CHG activity. Additionally, we found that pig corneas also reduced CHG activity. In contrast, dry eye drops and their major component, propylene glycol, which is commonly used as eyewash material, did not have an impact on CHG activity. Our results demonstrate the effect of ocular microenvironmental factors on CHG activity and suggest that these factors may play a role in the development of amoeba resistance to CHG and treatment failure.
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12
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Wang N, Sun H, Liu D, Jiang X, Zheng M, Zhu W, Liu Q, Zheng W, Feng X. Ac-HSP20 Is Associated With the Infectivity and Encystation of Acanthamoeba castellanii. Front Microbiol 2021; 11:595080. [PMID: 33510719 PMCID: PMC7835678 DOI: 10.3389/fmicb.2020.595080] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2020] [Accepted: 12/01/2020] [Indexed: 11/15/2022] Open
Abstract
Acanthamoeba castellanii is a pathogenic and opportunistic free-living amoeba that causes Acanthamoeba keratitis (AK) and granulomatous amebic encephalitis (GAE) in immunocompromised individuals. The biological and pathogenic characterizations behind this opportunistic protozoan is not fully understood. This study aimed to determine the biological functions of heat shock protein (HSP)-20 of A. castellanii (Ac-HSP20) involved in the maintenance of life cycle and the infectivity of A. castellanii. Immunoscreening A. castellanii cDNA library with A. castellanii infected rabbit sera identified three positive clones, one of them was a putative heat shock protein (Ac-HSP20). The recombinant 23 kDa Ac-HSP20 protein (rAc-HSP20) was successfully expressed in Escherichia coli BL21 (DE3) and purified using metal affinity chromatography. The rabbits immunized with rAc-HSP20 produced high titer antibody (1:25,600). Immunolocalization with the antibody identified the expression of native Ac-HSP20 on the surface of both A. castellanii trophozoites and cysts. Further, Western blot with antibody identified that the expression of native Ac-HSP20 was 7.5 times higher in cysts than in trophozoites. Blocking Ac-HSP20 on the membrane of trophozoites with specific antibody or silencing Ac-hsp20 gene transcription by siRNA inhibited their transformation into cysts at the early stage but returned to normal at the late stage by stimulating the transcription of Ac-hsp20. Incubation of trophozoites with anti-Ac-HSP20 IgG increased macrophage-involved phagocytosis to the protozoa and inhibited trophozoite infectivity on the cornea of rabbits compared with that without antibody. Our study provides that Ac-HSP20 is a surface antigen involved in the encystation and infectivity of A. castellanii and thus an important target for vaccine and drug development.
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Affiliation(s)
- Ningning Wang
- Department of Pathogenic Biology, Jilin Medical University, Jilin City, China
| | - Hongyu Sun
- Department of Pathogenic Biology, Jilin Medical University, Jilin City, China
| | - Di Liu
- Department of Pathogenic Biology, Jilin Medical University, Jilin City, China
| | - Xiaoming Jiang
- Department of Pathogenic Biology, Jilin Medical University, Jilin City, China
| | - Meiyu Zheng
- Department of Pathogenic Biology, Jilin Medical University, Jilin City, China
| | - Wenhe Zhu
- Department of Pathogenic Biology, Jilin Medical University, Jilin City, China
| | - Quan Liu
- School of Life Sciences and Engineering, Foshan University, Foshan, China
| | - Wenyu Zheng
- Department of Microsurgery, Jilin City Central Hospital, Jilin City, China
| | - Xianmin Feng
- Department of Pathogenic Biology, Jilin Medical University, Jilin City, China
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13
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Bínová E, Bína D, Nohýnková E. DNA content in Acanthamoeba during two stress defense reactions: Encystation, pseudocyst formation and cell cycle. Eur J Protistol 2020; 77:125745. [PMID: 33218872 DOI: 10.1016/j.ejop.2020.125745] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Revised: 08/22/2020] [Accepted: 10/19/2020] [Indexed: 12/01/2022]
Abstract
During environmental stress, the vegetative cells of the facultative pathogenic amoeba Acanthamoeba castellanii reversibly differentiate into resistant dormant stages, namely, cysts or pseudocysts. The type of resistant stage depends on the nature and duration of the stressor. Cell differentiation is accompanied by changes in morphology and cellular metabolism. Moreover, cell differentiation is also expected to be closely linked to the regulation of the cell cycle and, thus, to cellular DNA content. While the existence of the resistant stages in A. castellanii is well known, there is no consensus regarding the relationship between differentiation and cell cycle progression. In the present work, we used flow cytometry analysis to explore the changes in the DNA content during Acanthamoeba encystation and pseudocyst formation. Our results strongly indicate that A. castellanii enters encystation from the G2 phase of the cell cycle. In contrast, differentiation into pseudocysts can begin in the G1 and G2 phases. In addition, we present a phylogenetic analysis and classification of the main cell cycle regulators, namely, cyclin-dependent kinases and cyclins that are found in the genome of A. castellanii.
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Affiliation(s)
- Eva Bínová
- Institute of Immunology and Microbiology, First Faculty of Medicine, Charles University, Studnickova 7, 128 00 Prague 2, Czech Republic
| | - David Bína
- Faculty of Science, University of South Bohemia, Branišovská 1760 and The Czech Academy of Sciences, Biology Centre, Branišovská 31, 370 05 České Budějovice, Czech Republic
| | - Eva Nohýnková
- Institute of Immunology and Microbiology, First Faculty of Medicine, Charles University, Studnickova 7, 128 00 Prague 2, Czech Republic.
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14
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Dickson A, Cooper E, Fakae LB, Wang B, Chan KLA, Elsheikha HM. In Vitro Growth- and Encystation-Inhibitory Efficacies of Matcha Green Tea and Epigallocatechin Gallate Against Acanthameoba Castellanii. Pathogens 2020; 9:pathogens9090763. [PMID: 32957663 PMCID: PMC7558711 DOI: 10.3390/pathogens9090763] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Revised: 08/31/2020] [Accepted: 09/09/2020] [Indexed: 11/25/2022] Open
Abstract
We examined the inhibitory effect of matcha green tea (Camellia sinensis) and epigallocatechin gallate (EGCg; the most abundant catechin in tea) on the vegetative growth and encystation of Acanthamoeba castellanii T4 genotype. The sulforhodamine B (SRB) stain-based colorimetric assay and hemocytometer counting were used to determine the reduction in A. castellanii trophozoite proliferation and encystation, in response to treatment with C. sinensis or EGCg. Fourier transform infrared (FTIR) microscopy was used to analyze chemical changes in the trophozoites and cysts due to C. sinensis treatment. Hot brewed and cold brewed matcha inhibited the growth of trophozoites by >40% at a 100 % concentration. EGCg at concentrations of 50 to 500 µM significantly inhibited the trophozoite growth compared to control. Hot brewed matcha (100% concentration) also showed an 87% reduction in the rate of encystation compared to untreated control. Although 500 µM of EGCg increased the rate of encystation by 36.3%, 1000 µM reduced it by 27.7%. Both percentages were not significant compared to control. C. sinensis induced more cytotoxicity to Madin Darby canine kidney cells compared to EGCg. FTIR chemical fingerprinting analysis showed that treatment with brewed matcha significantly increased the levels of glycogen and carbohydrate in trophozoites and cysts.
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Affiliation(s)
- Ameliya Dickson
- School of Veterinary Medicine and Science, Faculty of Medicine and Health Sciences, University of Nottingham, Loughborough LE12 5RD, UK; (A.D.); (E.C.); (L.B.F.)
| | - Elise Cooper
- School of Veterinary Medicine and Science, Faculty of Medicine and Health Sciences, University of Nottingham, Loughborough LE12 5RD, UK; (A.D.); (E.C.); (L.B.F.)
| | - Lenu B. Fakae
- School of Veterinary Medicine and Science, Faculty of Medicine and Health Sciences, University of Nottingham, Loughborough LE12 5RD, UK; (A.D.); (E.C.); (L.B.F.)
| | - Bo Wang
- School of Mathematics and Actuarial Science, University of Leicester, Leicester LE1 7RH, UK;
| | - Ka Lung Andrew Chan
- Institute of Pharmaceutical Science, King’s College London, London SE1 9NH, UK;
| | - Hany M. Elsheikha
- School of Veterinary Medicine and Science, Faculty of Medicine and Health Sciences, University of Nottingham, Loughborough LE12 5RD, UK; (A.D.); (E.C.); (L.B.F.)
- Correspondence: ; Tel.: +44-0115-951-6445
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15
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Abstract
The evolutionary history of Acanthamoeba has been substantially resolved by the 18S rDNA phylogeny which made it possible to delimit the main lines associated with some classical species. Some of them have proven to be polyphyletic, but the inappropriate use of treating under the same names unrelated strains persists. In this study, phylogenies based on the complete genes of nuclear and mitochondrial rDNA were compared, in order to verify the congruence of the different lines. Various groups can thus be identified, some of which associated with the type strains of given species. Recognizing them only by their species names would significantly reduce the current confusion, in addition to logically following basic taxonomic rules. In this manner, the well-known polyphyletic taxa A. castellanii and A. polyphaga, are restricted to the two lines specified by their type strains, while other widely used strains like Neff and Linc-AP1 that are often confused with the previous ones, can be assigned to their own lines. New species are potentially present in other groups and additional efforts are needed to delimit them.
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16
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Quinet T, Samba-Louaka A, Héchard Y, Van Doninck K, Van der Henst C. Delayed cytokinesis generates multinuclearity and potential advantages in the amoeba Acanthamoeba castellanii Neff strain. Sci Rep 2020; 10:12109. [PMID: 32694508 PMCID: PMC7374626 DOI: 10.1038/s41598-020-68694-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Accepted: 06/26/2020] [Indexed: 12/29/2022] Open
Abstract
Multinuclearity is a widespread phenomenon across the living world, yet how it is achieved, and the potential related advantages, are not systematically understood. In this study, we investigate multinuclearity in amoebae. We observe that non-adherent amoebae are giant multinucleate cells compared to adherent ones. The cells solve their multinuclearity by a stretchy cytokinesis process with cytosolic bridge formation when adherence resumes. After initial adhesion to a new substrate, the progeny of the multinucleate cells is more numerous than the sibling cells generated from uninucleate amoebae. Hence, multinucleate amoebae show an advantage for population growth when the number of cells is quantified over time. Multiple nuclei per cell are observed in different amoeba species, and the lack of adhesion induces multinuclearity in diverse protists such as Acanthamoeba castellanii, Vermamoeba vermiformis, Naegleria gruberi and Hartmannella rhysodes. In this study, we observe that agitation induces a cytokinesis delay, which promotes multinuclearity. Hence, we propose the hypothesis that multinuclearity represents a physiological adaptation under non-adherent conditions that can lead to biologically relevant advantages.
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Affiliation(s)
- Théo Quinet
- Laboratory of Evolutionary Genetics and Ecology, URBE, University of Namur, Namur, Belgium
| | - Ascel Samba-Louaka
- Laboratoire Ecologie et Biologie des Interactions, Equipe Microbiologie de L'Eau, Université de Poitiers, UMR CNRS 7267, 86073, Poitiers, France
| | - Yann Héchard
- Laboratoire Ecologie et Biologie des Interactions, Equipe Microbiologie de L'Eau, Université de Poitiers, UMR CNRS 7267, 86073, Poitiers, France
| | - Karine Van Doninck
- Laboratory of Evolutionary Genetics and Ecology, URBE, University of Namur, Namur, Belgium
| | - Charles Van der Henst
- Laboratory of Evolutionary Genetics and Ecology, URBE, University of Namur, Namur, Belgium. .,Research Unit in the Biology of Microorganisms (URBM), NARILIS, University of Namur (UNamur), Namur, Belgium. .,Microbial Resistance and Drug Discovery, Center for Structural Biology (CSB), Flanders Institute for Biotechnology (VIB), Vrije Universiteit Brussel (VUB), Pleinlaan 2, Building E-3, 1050, Brussels, Belgium. .,Structural Biology Brussels, Vrije Universiteit Brussel (VUB), Brussels, Belgium.
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17
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Drug Discovery against Acanthamoeba Infections: Present Knowledge and Unmet Needs. Pathogens 2020; 9:pathogens9050405. [PMID: 32456110 PMCID: PMC7281112 DOI: 10.3390/pathogens9050405] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Revised: 05/09/2020] [Accepted: 05/12/2020] [Indexed: 12/12/2022] Open
Abstract
Although major strides have been made in developing and testing various anti-acanthamoebic drugs, recurrent infections, inadequate treatment outcomes, health complications, and side effects associated with the use of currently available drugs necessitate the development of more effective and safe therapeutic regimens. For any new anti-acanthamoebic drugs to be more effective, they must have either superior potency and safety or at least comparable potency and an improved safety profile compared to the existing drugs. The development of the so-called 'next-generation' anti-acanthamoebic agents to address this challenge is an active area of research. Here, we review the current status of anti-acanthamoebic drugs and discuss recent progress in identifying novel pharmacological targets and new approaches, such as drug repurposing, development of small interfering RNA (siRNA)-based therapies and testing natural products and their derivatives. Some of the discussed approaches have the potential to change the therapeutic landscape of Acanthamoeba infections.
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18
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Brahim Belhaouari D, Baudoin JP, Gnankou F, Di Pinto F, Colson P, Aherfi S, La Scola B. Evidence of a Cellulosic Layer in Pandoravirus massiliensis Tegument and the Mystery of the Genetic Support of Its Biosynthesis. Front Microbiol 2019; 10:2932. [PMID: 31921087 PMCID: PMC6932959 DOI: 10.3389/fmicb.2019.02932] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Accepted: 12/05/2019] [Indexed: 11/13/2022] Open
Abstract
Pandoraviruses are giant viruses of ameba with 1 μm-long virions. They have an ovoid morphology and are surrounded by a tegument-like structure lacking any capsid protein nor any gene encoding a capsid protein. In this work, we studied the ultrastructure of the tegument surrounding Pandoravirus massiliensis virions and noticed that this tegument is composed of a peripheral sugar layer, an electron-dense membrane, and a thick electron-dense layer consisting in several tubules arranged in a helicoidal structure resembling that of cellulose. Pandoravirus massiliensis particles were stained by Calcofluor white, a fluorescent dye of cellulose, and the enzymatic treatment of particles by cellulase showed the degradation of the viral tegument. We first hypothesized that the cellulose tegument could be synthesized by enzymes encoded by the virus. Bioinformatic analyses revealed in P. massiliensis, a candidate gene encoding a putative cellulose synthase, with a homology with the BcsA domain, one of the catalytic subunits of the bacterial cellulose synthase, but with a low level of homology. This gene was transcribed during the replicative cycle of P. massiliensis, but several arguments run counter to this hypothesis. Indeed, even if this gene is present in other pandoraviruses, the one of the strain studied is the only one to have this BcsA domain and no other enzymes involved in the synthesis of cellulose could be detected, although we cannot rule out that such genes could have been undetected among the large proportion of Orfans of pandoraviruses. As an alternative, we investigated whether P. massiliensis could divert the cellulose synthesis machinery of the ameba to its own account. Indeed, contrary to what is observed in the case of infections with other giant viruses such as mimiviruses, it appears that the transcription of the ameba, at least for the cellulose synthase gene, continues throughout the growth phase of particles of P. massiliensis. Finally, we believe that this scenario is more plausible. If confirmed, it could be a unique mechanism in the virosphere.
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Affiliation(s)
- Djamal Brahim Belhaouari
- Microbes, Evolution, Phylogeny and Infection (MEPHI), UM63, Institut de Recherche pour le Développement (IRD), Assistance Publique - Hôpitaux de Marseille (AP-HM), Aix-Marseille University, Marseille, France
| | - Jean-Pierre Baudoin
- Microbes, Evolution, Phylogeny and Infection (MEPHI), UM63, Institut de Recherche pour le Développement (IRD), Assistance Publique - Hôpitaux de Marseille (AP-HM), Aix-Marseille University, Marseille, France
| | - Franck Gnankou
- Microbes, Evolution, Phylogeny and Infection (MEPHI), UM63, Institut de Recherche pour le Développement (IRD), Assistance Publique - Hôpitaux de Marseille (AP-HM), Aix-Marseille University, Marseille, France
| | - Fabrizio Di Pinto
- Microbes, Evolution, Phylogeny and Infection (MEPHI), UM63, Institut de Recherche pour le Développement (IRD), Assistance Publique - Hôpitaux de Marseille (AP-HM), Aix-Marseille University, Marseille, France
| | - Philippe Colson
- Microbes, Evolution, Phylogeny and Infection (MEPHI), UM63, Institut de Recherche pour le Développement (IRD), Assistance Publique - Hôpitaux de Marseille (AP-HM), Aix-Marseille University, Marseille, France.,IHU Méditerranée Infection, Marseille, France
| | - Sarah Aherfi
- Microbes, Evolution, Phylogeny and Infection (MEPHI), UM63, Institut de Recherche pour le Développement (IRD), Assistance Publique - Hôpitaux de Marseille (AP-HM), Aix-Marseille University, Marseille, France.,IHU Méditerranée Infection, Marseille, France
| | - Bernard La Scola
- Microbes, Evolution, Phylogeny and Infection (MEPHI), UM63, Institut de Recherche pour le Développement (IRD), Assistance Publique - Hôpitaux de Marseille (AP-HM), Aix-Marseille University, Marseille, France.,IHU Méditerranée Infection, Marseille, France
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19
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Siddiqui R, Roberts SK, Ong TYY, Mungroo MR, Anwar A, Khan NA. Novel insights into the potential role of ion transport in sensory perception in Acanthamoeba. Parasit Vectors 2019; 12:538. [PMID: 31727139 PMCID: PMC6857129 DOI: 10.1186/s13071-019-3785-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2019] [Accepted: 11/04/2019] [Indexed: 11/25/2022] Open
Abstract
Background Acanthamoeba is well known to produce a blinding keratitis and serious brain infection known as encephalitis. Effective treatment is problematic, and can continue up to a year, and even then, recurrence can ensue. Partly, this is due to the capability of vegetative amoebae to convert into resistant cysts. Cysts can persist in an inactive form for decades while retaining their pathogenicity. It is not clear how Acanthamoeba cysts monitor environmental changes, and determine favourable conditions leading to their emergence as viable trophozoites. Methods The role of ion transporters in the encystation and excystation of Acanthamoeba remains unclear. Here, we investigated the role of sodium, potassium and calcium ion transporters as well as proton pump inhibitors on A. castellanii encystation and excystation and their effects on trophozoites. Results Remarkably 3′,4′-dichlorobenzamil hydrochloride a sodium–calcium exchange inhibitor, completely abolished excystation of Acanthamoeba. Furthermore, lanthanum oxide and stevioside hydrate, both potassium transport inhibitors, resulted in the partial inhibition of Acanthamoeba excystation. Conversely, none of the ion transport inhibitors affected encystation or had any effects on Acanthamoeba trophozoites viability. Conclusions The present study indicates that ion transporters are involved in sensory perception of A. castellanii suggesting their value as potential therapeutic targets to block cellular differentiation that presents a significant challenge in the successful prognosis of Acanthamoeba infections.
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Affiliation(s)
- Ruqaiyyah Siddiqui
- Department of Biology, Chemistry and Environmental Sciences, College of Arts and Sciences, American University of Sharjah, University City, Sharjah, United Arab Emirates.
| | | | - Timothy Yu Yee Ong
- Department of Biological Sciences, School of Science and Technology, Sunway University, Bandar Sunway, Malaysia
| | - Mohammad Ridwane Mungroo
- Department of Biological Sciences, School of Science and Technology, Sunway University, Bandar Sunway, Malaysia
| | - Areeba Anwar
- Department of Biological Sciences, School of Science and Technology, Sunway University, Bandar Sunway, Malaysia
| | - Naveed Ahmed Khan
- Department of Biology, Chemistry and Environmental Sciences, College of Arts and Sciences, American University of Sharjah, University City, Sharjah, United Arab Emirates
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