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Angelici MC, Walochnik J, Calderaro A, Saxinger L, Dacks JB. Free-living amoebae and other neglected protistan pathogens: Health emergency signals? Eur J Protistol 2020; 77:125760. [PMID: 33340850 DOI: 10.1016/j.ejop.2020.125760] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 10/25/2020] [Accepted: 11/13/2020] [Indexed: 02/08/2023]
Abstract
Protistan parasites have an undisputed global health impact. However, outside of a few key exceptions, e.g. the agent of malaria, most of these infectious agents are neglected as important health threats. The Symposium entitled "Free-living amoebae and neglected pathogenic protozoa: health emergency signals?" held at the European Congress of Protistology in Rome, July 2019, brought together researchers addressing scientific and clinical questions about some of these fascinating organisms. Topics presented included the molecular basis of pathogenicity in Acanthamoeba; genomics of Naegleria fowleri; and epidemiology of poorly diagnosed enteric protistan species, including Giardia, Cryptosporidium, Blastocystis, Dientamoeba. The Symposium aim was to excite the audience about the opportunities and challenges of research in these underexplored organisms and to underline the public health implications of currently under-appreciated protistan infections. The major take home message is that any knowledge that we gain about these organisms will allow us to better address them, in terms of monitoring and treatment, as sources of future health emergencies.
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Affiliation(s)
| | - Julia Walochnik
- Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria
| | - Adriana Calderaro
- Department of Medicine and Surgery, University of Parma, Parma, Italy
| | - Lynora Saxinger
- Division of Infectious Diseases, Department of Medicine, University of Alberta, Alberta, Canada
| | - Joel B Dacks
- Division of Infectious Diseases, Department of Medicine, University of Alberta, Alberta, Canada; Institute of Parasitology, Biology Centre, Czech Academy of Sciences České Budějovice, Czech Republic.
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2
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Diaz N, Lico C, Capodicasa C, Baschieri S, Dessì D, Benvenuto E, Fiori PL, Rappelli P. Production and Functional Characterization of a Recombinant Predicted Pore-Forming Protein (TVSAPLIP12) of Trichomonas vaginalis in Nicotiana benthamiana Plants. Front Cell Infect Microbiol 2020; 10:581066. [PMID: 33117734 PMCID: PMC7561387 DOI: 10.3389/fcimb.2020.581066] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Accepted: 08/31/2020] [Indexed: 01/05/2023] Open
Abstract
Pore-forming proteins (PFPs) are a group of functionally versatile molecules distributed in all domains of life, and several microbial pathogens notably use members of this class of proteins as cytotoxic effectors. Among pathogenic protists, Entamoeba histolytica, and Naegleria fowleri display a range of pore-forming toxins belonging to the Saposin-Like Proteins (Saplip) family: Amoebapores and Naegleriapores. Following the genome sequencing of Trichomonas vaginalis, we identified a gene family of 12 predicted saposin-like proteins (TvSaplips): this work focuses on investigating the potential role of TvSaplips as cytopathogenetic effectors. We provide evidence that TvSaplip12 gene expression is potently upregulated upon T. vaginalis contact with target cells. We cloned and expressed recombinant TvSaplip12 in planta and we demonstrate haemolytic, cytotoxic, and bactericidal activities of rTvSaplip12 in vitro. Also, evidence for TvSaplip subcellular discrete distribution in cytoplasmic granules is presented. Altogether, our results highlight the importance of TvSaplip in T. vaginalis pathogenesis, depicting its involvement in the cytolytic and bactericidal activities during the infection process, leading to predation on host cells and resident vaginal microbiota for essential nutrients acquisition. This hence suggests a potential key role for TvSaplip12 in T. vaginalis pathogenesis as a candidate Trichopore.
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Affiliation(s)
- Nicia Diaz
- Department of Biomedical Sciences, University of Sassari, Sassari, Italy
| | - Chiara Lico
- Laboratory of Biotechnology, Italian National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA) Casaccia Research Center, Rome, Italy
| | - Cristina Capodicasa
- Laboratory of Biotechnology, Italian National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA) Casaccia Research Center, Rome, Italy
| | - Selene Baschieri
- Laboratory of Biotechnology, Italian National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA) Casaccia Research Center, Rome, Italy
| | - Daniele Dessì
- Department of Biomedical Sciences, University of Sassari, Sassari, Italy
- Mediterranean Center for Diseases Control, Sassari, Italy
| | - Eugenio Benvenuto
- Laboratory of Biotechnology, Italian National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA) Casaccia Research Center, Rome, Italy
| | - Pier Luigi Fiori
- Department of Biomedical Sciences, University of Sassari, Sassari, Italy
- Mediterranean Center for Diseases Control, Sassari, Italy
| | - Paola Rappelli
- Department of Biomedical Sciences, University of Sassari, Sassari, Italy
- Mediterranean Center for Diseases Control, Sassari, Italy
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3
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Maliehe M, Ntoi MA, Lahiri S, Folorunso OS, Ogundeji AO, Pohl CH, Sebolai OM. Environmental Factors That Contribute to the Maintenance of Cryptococcus neoformans Pathogenesis. Microorganisms 2020; 8:microorganisms8020180. [PMID: 32012843 PMCID: PMC7074686 DOI: 10.3390/microorganisms8020180] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Revised: 12/04/2019] [Accepted: 12/11/2019] [Indexed: 02/07/2023] Open
Abstract
The ability of microorganisms to colonise and display an intracellular lifestyle within a host body increases their fitness to survive and avoid extinction. This host–pathogen association drives microbial evolution, as such organisms are under selective pressure and can become more pathogenic. Some of these microorganisms can quickly spread through the environment via transmission. The non-transmittable fungal pathogens, such as Cryptococcus, probably return into the environment upon decomposition of the infected host. This review analyses whether re-entry of the pathogen into the environment causes restoration of its non-pathogenic state or whether environmental factors and parameters assist them in maintaining pathogenesis. Cryptococcus (C.) neoformans is therefore used as a model organism to evaluate the impact of environmental stress factors that aid the survival and pathogenesis of C. neoformans intracellularly and extracellularly.
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4
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Betanzos A, Bañuelos C, Orozco E. Host Invasion by Pathogenic Amoebae: Epithelial Disruption by Parasite Proteins. Genes (Basel) 2019; 10:E618. [PMID: 31416298 PMCID: PMC6723116 DOI: 10.3390/genes10080618] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Revised: 04/25/2019] [Accepted: 04/29/2019] [Indexed: 02/07/2023] Open
Abstract
The epithelium represents the first and most extensive line of defence against pathogens, toxins and pollutant agents in humans. In general, pathogens have developed strategies to overcome this barrier and use it as an entrance to the organism. Entamoeba histolytica, Naegleriafowleri and Acanthamoeba spp. are amoebae mainly responsible for intestinal dysentery, meningoencephalitis and keratitis, respectively. These amoebae cause significant morbidity and mortality rates. Thus, the identification, characterization and validation of molecules participating in host-parasite interactions can provide attractive targets to timely intervene disease progress. In this work, we present a compendium of the parasite adhesins, lectins, proteases, hydrolases, kinases, and others, that participate in key pathogenic events. Special focus is made for the analysis of assorted molecules and mechanisms involved in the interaction of the parasites with epithelial surface receptors, changes in epithelial junctional markers, implications on the barrier function, among others. This review allows the assessment of initial host-pathogen interaction, to correlate it to the potential of parasite invasion.
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Affiliation(s)
- Abigail Betanzos
- Consejo Nacional de Ciencia y Tecnología (CONACYT), Mexico City 03940, Mexico
- Departamento de Infectómica y Patogénesis Molecular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV-IPN), Mexico City 07360, Mexico
| | - Cecilia Bañuelos
- Coordinación General de Programas de Posgrado Multidisciplinarios, Programa de Doctorado Transdisciplinario en Desarrollo Científico y Tecnológico para la Sociedad, CINVESTAV-IPN, Mexico City 07360, Mexico
| | - Esther Orozco
- Departamento de Infectómica y Patogénesis Molecular, CINVESTAV-IPN, Mexico City 07360, Mexico.
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5
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Affiliation(s)
- Mohammad Ridwane Mungroo
- Department of Biological Sciences, School of Science and Technology, Sunway University, Bandar Sunway, Malaysia
| | - Naveed Ahmed Khan
- Department of Biological Sciences, School of Science and Technology, Sunway University, Bandar Sunway, Malaysia
| | - Ruqaiyyah Siddiqui
- Department of Biological Sciences, School of Science and Technology, Sunway University, Bandar Sunway, Malaysia
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6
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Delgado-Galván CJ, Padilla-Vaca F, Montiel FBR, Rangel-Serrano Á, Paramo-Pérez I, Anaya-Velázquez F, Franco B. Red fluorescent protein (DsRFP) optimization for Entamoeba histolytica expression. Exp Parasitol 2018; 187:86-92. [PMID: 29476758 DOI: 10.1016/j.exppara.2018.01.018] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2017] [Revised: 01/05/2018] [Accepted: 01/30/2018] [Indexed: 12/01/2022]
Abstract
Entamoeba histolytica genetic organization and genome structure is complex and under intense research. The genome is fully sequenced, and several tools have been developed for the molecular study of this organism. Nevertheless, good protein tracking tags that are easy to measure and image, like the fluorescent proteins are lacking. In this report, we codon-optimized the red fluorescent protein from the coral Discosoma striata (DsRFP) for its use in E. histolytica and demonstrated functionality in vivo. We envision that this protein can be widely used for the development of transcriptional reporter systems and protein-tagging applications.
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Affiliation(s)
- Cindy Jazmín Delgado-Galván
- Departamento de Biología, División de Ciencias Naturales y Exactas, Universidad de Guanajuato, Noria Alta s/n, Guanajuato, Gto. 36050, Mexico
| | - Felipe Padilla-Vaca
- Departamento de Biología, División de Ciencias Naturales y Exactas, Universidad de Guanajuato, Noria Alta s/n, Guanajuato, Gto. 36050, Mexico
| | - Fátima Berenice Ramírez Montiel
- Departamento de Biología, División de Ciencias Naturales y Exactas, Universidad de Guanajuato, Noria Alta s/n, Guanajuato, Gto. 36050, Mexico
| | - Ángeles Rangel-Serrano
- Departamento de Biología, División de Ciencias Naturales y Exactas, Universidad de Guanajuato, Noria Alta s/n, Guanajuato, Gto. 36050, Mexico
| | - Itzel Paramo-Pérez
- Departamento de Biología, División de Ciencias Naturales y Exactas, Universidad de Guanajuato, Noria Alta s/n, Guanajuato, Gto. 36050, Mexico
| | - Fernando Anaya-Velázquez
- Departamento de Biología, División de Ciencias Naturales y Exactas, Universidad de Guanajuato, Noria Alta s/n, Guanajuato, Gto. 36050, Mexico
| | - Bernardo Franco
- Departamento de Biología, División de Ciencias Naturales y Exactas, Universidad de Guanajuato, Noria Alta s/n, Guanajuato, Gto. 36050, Mexico.
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7
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Mazumdar R, Endler L, Monoyios A, Hess M, Bilic I. Establishment of a de novo Reference Transcriptome of Histomonas meleagridis Reveals Basic Insights About Biological Functions and Potential Pathogenic Mechanisms of the Parasite. Protist 2017; 168:663-685. [DOI: 10.1016/j.protis.2017.09.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Revised: 08/21/2017] [Accepted: 09/23/2017] [Indexed: 12/28/2022]
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8
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Siddiqui R, Ali IKM, Cope JR, Khan NA. Biology and pathogenesis of Naegleria fowleri. Acta Trop 2016; 164:375-394. [PMID: 27616699 DOI: 10.1016/j.actatropica.2016.09.009] [Citation(s) in RCA: 113] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2016] [Revised: 09/06/2016] [Accepted: 09/06/2016] [Indexed: 12/13/2022]
Abstract
Naegleria fowleri is a protist pathogen that can cause lethal brain infection. Despite decades of research, the mortality rate related with primary amoebic meningoencephalitis owing to N. fowleri remains more than 90%. The amoebae pass through the nose to enter the central nervous system killing the host within days, making it one of the deadliest opportunistic parasites. Accordingly, we present an up to date review of the biology and pathogenesis of N. fowleri and discuss needs for future research against this fatal infection.
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9
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Malik E, Dennison SR, Harris F, Phoenix DA. pH Dependent Antimicrobial Peptides and Proteins, Their Mechanisms of Action and Potential as Therapeutic Agents. Pharmaceuticals (Basel) 2016; 9:ph9040067. [PMID: 27809281 PMCID: PMC5198042 DOI: 10.3390/ph9040067] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Revised: 10/25/2016] [Accepted: 10/26/2016] [Indexed: 12/16/2022] Open
Abstract
Antimicrobial peptides (AMPs) are potent antibiotics of the innate immune system that have been extensively investigated as a potential solution to the global problem of infectious diseases caused by pathogenic microbes. A group of AMPs that are increasingly being reported are those that utilise pH dependent antimicrobial mechanisms, and here we review research into this area. This review shows that these antimicrobial molecules are produced by a diverse spectrum of creatures, including vertebrates and invertebrates, and are primarily cationic, although a number of anionic examples are known. Some of these molecules exhibit high pH optima for their antimicrobial activity but in most cases, these AMPs show activity against microbes that present low pH optima, which reflects the acidic pH generally found at their sites of action, particularly the skin. The modes of action used by these molecules are based on a number of major structure/function relationships, which include metal ion binding, changes to net charge and conformational plasticity, and primarily involve the protonation of histidine, aspartic acid and glutamic acid residues at low pH. The pH dependent activity of pore forming antimicrobial proteins involves mechanisms that generally differ fundamentally to those used by pH dependent AMPs, which can be described by the carpet, toroidal pore and barrel-stave pore models of membrane interaction. A number of pH dependent AMPs and antimicrobial proteins have been developed for medical purposes and have successfully completed clinical trials, including kappacins, LL-37, histatins and lactoferrin, along with a number of their derivatives. Major examples of the therapeutic application of these antimicrobial molecules include wound healing as well as the treatment of multiple cancers and infections due to viruses, bacteria and fungi. In general, these applications involve topical administration, such as the use of mouth washes, cream formulations and hydrogel delivery systems. Nonetheless, many pH dependent AMPs and antimicrobial proteins have yet to be fully characterized and these molecules, as a whole, represent an untapped source of novel biologically active agents that could aid fulfillment of the urgent need for alternatives to conventional antibiotics, helping to avert a return to the pre-antibiotic era.
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Affiliation(s)
- Erum Malik
- School of Forensic and Applied Sciences, University of Central Lancashire, Preston PR1 2HE, UK.
| | - Sarah R Dennison
- School of Pharmacy and Biological Sciences, University of Central Lancashire, Preston PR1 2HE, UK.
| | - Frederick Harris
- School of Forensic and Applied Sciences, University of Central Lancashire, Preston PR1 2HE, UK.
| | - David A Phoenix
- Office of the Vice Chancellor, London South Bank University, 103 Borough Road, London SE1 0AA, UK.
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10
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Reverey JF, Jeon JH, Bao H, Leippe M, Metzler R, Selhuber-Unkel C. Superdiffusion dominates intracellular particle motion in the supercrowded cytoplasm of pathogenic Acanthamoeba castellanii. Sci Rep 2015; 5:11690. [PMID: 26123798 PMCID: PMC5155589 DOI: 10.1038/srep11690] [Citation(s) in RCA: 84] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2015] [Accepted: 06/01/2015] [Indexed: 12/21/2022] Open
Abstract
Acanthamoebae are free-living protists and human pathogens, whose cellular functions and pathogenicity strongly depend on the transport of intracellular vesicles and granules through the cytosol. Using high-speed live cell imaging in combination with single-particle tracking analysis, we show here that the motion of endogenous intracellular particles in the size range from a few hundred nanometers to several micrometers in Acanthamoeba castellanii is strongly superdiffusive and influenced by cell locomotion, cytoskeletal elements, and myosin II. We demonstrate that cell locomotion significantly contributes to intracellular particle motion, but is clearly not the only origin of superdiffusivity. By analyzing the contribution of microtubules, actin, and myosin II motors we show that myosin II is a major driving force of intracellular motion in A. castellanii. The cytoplasm of A. castellanii is supercrowded with intracellular vesicles and granules, such that significant intracellular motion can only be achieved by actively driven motion, while purely thermally driven diffusion is negligible.
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Affiliation(s)
- Julia F Reverey
- Institute for Materials Science, Biocompatible Nanomaterials, Christian-Albrechts-Universität zu Kiel, Kaiserstr. 2, D-24143 Kiel, Germany
| | - Jae-Hyung Jeon
- School of Physics, Korea Institute for Advanced Study, Seoul 130-722, Republic of Korea
| | - Han Bao
- Institute for Materials Science, Biocompatible Nanomaterials, Christian-Albrechts-Universität zu Kiel, Kaiserstr. 2, D-24143 Kiel, Germany
| | - Matthias Leippe
- Zoological Institute, Comparative Immunobiology, Christian-Albrechts-Universität zu Kiel, Olshausenstr.40, D-24098 Kiel, Germany
| | - Ralf Metzler
- 1] Institute of Physics &Astronomy, University of Potsdam, D-14776 Potsdam-Golm, Germany [2] Department of Physics, Tampere University of Technology, FI-30101 Tampere, Finland
| | - Christine Selhuber-Unkel
- Institute for Materials Science, Biocompatible Nanomaterials, Christian-Albrechts-Universität zu Kiel, Kaiserstr. 2, D-24143 Kiel, Germany
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11
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Ralston KS. Chew on this: amoebic trogocytosis and host cell killing by Entamoeba histolytica. Trends Parasitol 2015; 31:442-52. [PMID: 26070402 DOI: 10.1016/j.pt.2015.05.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2015] [Revised: 05/04/2015] [Accepted: 05/05/2015] [Indexed: 01/23/2023]
Abstract
Entamoeba histolytica was named 'histolytica' (from histo-, 'tissue'; lytic-, 'dissolving') for its ability to destroy host tissues. Direct killing of host cells by the amoebae is likely to be the driving factor that underlies tissue destruction, but the mechanism was unclear. We recently showed that, after attaching to host cells, amoebae bite off and ingest distinct host cell fragments, and that this contributes to cell killing. We review this process, termed 'amoebic trogocytosis' (trogo-, 'nibble'), and how this process interplays with phagocytosis, or whole cell ingestion, in this organism. 'Nibbling' processes have been described in other microbes and in multicellular organisms. The discovery of amoebic trogocytosis in E. histolytica may also shed light on an evolutionarily conserved process for intercellular exchange.
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Affiliation(s)
- Katherine S Ralston
- Department of Microbiology and Molecular Genetics, University of California, Davis, CA 95616, USA.
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12
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Destoumieux-Garzón D, Duperthuy M, Vanhove AS, Schmitt P, Wai SN. Resistance to Antimicrobial Peptides in Vibrios. Antibiotics (Basel) 2014; 3:540-63. [PMID: 27025756 PMCID: PMC4790380 DOI: 10.3390/antibiotics3040540] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Revised: 09/25/2014] [Accepted: 10/08/2014] [Indexed: 12/19/2022] Open
Abstract
Vibrios are associated with a broad diversity of hosts that produce antimicrobial peptides (AMPs) as part of their defense against microbial infections. In particular, vibrios colonize epithelia, which function as protective barriers and express AMPs as a first line of chemical defense against pathogens. Recent studies have shown they can also colonize phagocytes, key components of the animal immune system. Phagocytes infiltrate infected tissues and use AMPs to kill the phagocytosed microorganisms intracellularly, or deliver their antimicrobial content extracellularly to circumvent tissue infection. We review here the mechanisms by which vibrios have evolved the capacity to evade or resist the potent antimicrobial defenses of the immune cells or tissues they colonize. Among their strategies to resist killing by AMPs, primarily vibrios use membrane remodeling mechanisms. In particular, some highly resistant strains substitute hexaacylated Lipid A with a diglycine residue to reduce their negative surface charge, thereby lowering their electrostatic interactions with cationic AMPs. As a response to envelope stress, which can be induced by membrane-active agents including AMPs, vibrios also release outer membrane vesicles to create a protective membranous shield that traps extracellular AMPs and prevents interaction of the peptides with their own membranes. Finally, once AMPs have breached the bacterial membrane barriers, vibrios use RND efflux pumps, similar to those of other species, to transport AMPs out of their cytoplasmic space.
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Affiliation(s)
- Delphine Destoumieux-Garzón
- Ecology of Coastal Marine Systems, CNRS, Ifremer, University of Montpellier, IRD, Place Eugène Bataillon, CC80, 34095 Montpellier, France.
| | - Marylise Duperthuy
- Department of Molecular Biology, The Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, 901 87 Umeå, Sweden.
| | - Audrey Sophie Vanhove
- Ecology of Coastal Marine Systems, CNRS, Ifremer, University of Montpellier, IRD, Place Eugène Bataillon, CC80, 34095 Montpellier, France.
| | - Paulina Schmitt
- Laboratorio de Genética e Inmunología Molecular, Instituto de Biología, Pontificia Universidad Católica de Valparaíso, Avenida Universidad 330, 2373223 Valparaíso, Chile.
| | - Sun Nyunt Wai
- Department of Molecular Biology, The Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, 901 87 Umeå, Sweden.
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Leippe M. Pore-forming toxins from pathogenic amoebae. Appl Microbiol Biotechnol 2014; 98:4347-53. [PMID: 24676751 DOI: 10.1007/s00253-014-5673-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2014] [Revised: 03/05/2014] [Accepted: 03/06/2014] [Indexed: 11/30/2022]
Abstract
Some amoeboid protozoans are facultative or obligate parasites in humans and bear an enormous cytotoxic potential that can result in severe destruction of host tissues and fatal diseases. Pathogenic amoebae produce soluble pore-forming polypeptides that bind to prokaryotic and eukaryotic target cell membranes and generate pores upon insertion and oligomerization. This review summerizes the current knowledge of such small protein toxins from amoebae, compares them with related proteins from other species, focuses on their three-dimensional structures, and gives insights into divergent activation mechanisms. The potential use of pore-forming toxins in biotechnology will be briefly outlined.
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Affiliation(s)
- Matthias Leippe
- Zoological Institute, Zoophysiology, University of Kiel, Olshausenstrasse 40, 24098, Kiel, Germany,
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14
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Abstract
The parasite Entamoeba histolytica causes amebic colitis and systemic amebiasis. Among the known amebic factors contributing to pathogenesis are signaling pathways involving heterotrimeric and Ras superfamily G proteins. Here, we review the current knowledge of the roles of heterotrimeric G protein subunits, Ras, Rho and Rab GTPase families in E. histolytica pathogenesis, as well as of their downstream signaling effectors and nucleotide cycle regulators. Heterotrimeric G protein signaling likely modulates amebic motility and attachment to and killing of host cells, in part through activation of an RGS-RhoGEF (regulator of G protein signaling-Rho guanine nucleotide exchange factor) effector. Rho family GTPases, as well as RhoGEFs and Rho effectors (formins and p21-activated kinases) regulate the dynamic actin cytoskeleton of E. histolytica and associated pathogenesis-related cellular processes, such as migration, invasion, phagocytosis and evasion of the host immune response by surface receptor capping. A remarkably large family of 91 Rab GTPases has multiple roles in a complex amebic vesicular trafficking system required for phagocytosis and pinocytosis and secretion of known virulence factors, such as amebapores and cysteine proteases. Although much remains to be discovered, recent studies of G protein signaling in E. histolytica have enhanced our understanding of parasitic pathogenesis and have also highlighted possible targets for pharmacological manipulation.
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15
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Baumel-Alterzon S, Weber C, Guillén N, Ankri S. Identification of dihydropyrimidine dehydrogenase as a virulence factor essential for the survival of Entamoeba histolytica in glucose-poor environments. Cell Microbiol 2012; 15:130-44. [PMID: 23016994 DOI: 10.1111/cmi.12036] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2012] [Revised: 09/11/2012] [Accepted: 09/19/2012] [Indexed: 11/28/2022]
Abstract
Adaptation to nutritional changes is a key feature for successful survival of a pathogen within its host. The protozoan parasite Entamoeba histolytica normally colonizes the human colon and in rare occasions, this parasite spread to distant organs, such as the liver. E. histolytica obtains most of its energy from the fermentation of glucose into ethanol. In this study, we were intrigued to know how this parasite reacts to changes in glucose availability and we addressed this issue by performing a DNA microarray analysis of gene expression. Results show that parasites that were adapted to growth in absence of glucose increased their virulence and altered the transcription of several genes. One of these genes is the dihydropyrimidine dehydrogenase (DPD), which is involved in degradation of pyrimidines. We showed that this gene is crucial for the parasite's growth when the availability of glucose is limited. These data contribute to our understanding of the parasite's ability to survive in glucose-poor environments and reveal a new role for the DPD enzyme.
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Affiliation(s)
- Sharon Baumel-Alterzon
- Department of Molecular Microbiology, Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel
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16
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A functional study of nucleocytoplasmic transport signals of the EhNCABP166 protein from Entamoeba histolytica. Parasitology 2012; 139:1697-710. [PMID: 22906852 DOI: 10.1017/s0031182012001199] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
EhNCABP166 is an Entamoeba histolytica actin-binding protein that localizes to the nucleus and cytoplasm. Bioinformatic analysis of the EhNCABP166 amino acid sequence shows the presence of 3 bipartite nuclear localization signals (NLS) and a nuclear export signal (NES). The present study aimed to investigate the functionality of these signals in 3 ways. First, we fused each potential NLS to a cytoplasmic domain of ehFLN to determine whether the localization of this domain could be altered by the presence of the NLSs. Furthermore, the localization of each domain of EhNCABP166 was determined. Similarly, we generated mutations in the first block of bipartite signals from the domains that contained these signals. Additionally, we added an NES to 2 constructs that were then evaluated. We confirmed the intranuclear localization of EhNCABP166 using transmission electron microscopy. Fusion of each NLS resulted in shuttling of the cytoplasmic domain to the nucleus. With the exception of 2 domains, all of the evaluated domains localized within the nucleus. A mutation in the first block of bipartite signals affected the localization of the domains containing an NLS. The addition of an NES shifted the localization of these domains to the cytoplasm. The results presented here establish EhNCABP166 as a protein containing functional nuclear localization signals and a nuclear export signal.
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17
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Hirt RP, de Miguel N, Nakjang S, Dessi D, Liu YC, Diaz N, Rappelli P, Acosta-Serrano A, Fiori PL, Mottram JC. Trichomonas vaginalis pathobiology new insights from the genome sequence. ADVANCES IN PARASITOLOGY 2012; 77:87-140. [PMID: 22137583 DOI: 10.1016/b978-0-12-391429-3.00006-x] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The draft genome of the common sexually transmitted pathogen Trichomonas vaginalis encodes one of the largest known proteome with 60,000 candidate proteins. This provides parasitologists and molecular cell biologists alike with exciting, yet challenging, opportunities to unravel the molecular features of the parasite's cellular systems and potentially the molecular basis of its pathobiology. Here, recent investigations addressing selected aspects of the parasite's molecular cell biology are discussed, including surface and secreted virulent factors, membrane trafficking, cell signalling, the degradome, and the potential role of RNA interference in the regulation of gene expression.
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Affiliation(s)
- Robert P Hirt
- Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, UK
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18
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Simanski M, Köten B, Schröder JM, Gläser R, Harder J. Antimicrobial RNases in cutaneous defense. J Innate Immun 2012; 4:241-7. [PMID: 22327069 DOI: 10.1159/000335029] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2011] [Accepted: 11/13/2011] [Indexed: 11/19/2022] Open
Abstract
Antimicrobial proteins (AMP) are small endogenous proteins which are capable of rapidly inactivating microorganisms at low micro- and nanomolar concentrations. Their significance in host defense is reflected by their wide distribution in nature. Several AMP have been isolated from human skin, and there is increasing evidence that AMP may play an important role in cutaneous defense. One important human AMP class comprises several antimicrobial members of the RNase A superfamily. Of these, two members, RNase 7 and RNase 5, have been implicated in cutaneous defense. This review gives an overview about our current knowledge on the potential role of RNase 7 and RNase 5 in protecting human skin from infection.
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Affiliation(s)
- Maren Simanski
- Department of Dermatology, University Hospital Schleswig-Holstein, Kiel Campus, Kiel, Germany
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19
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LEE YJ, KIM JH, SOHN HJ, LEE J, JUNG SY, CHWAE YJ, KIM K, PARK S, SHIN HJ. Effects of immunization with the rNfa1 protein on experimental Naegleria fowleri-PAM mice. Parasite Immunol 2011; 33:382-9. [DOI: 10.1111/j.1365-3024.2011.01296.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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20
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Campos-Parra A, Hernández-Cuevas N, Hernandez-Rivas R, Vargas M. EhNCABP166: A nucleocytoplasmic actin-binding protein from Entamoeba histolytica. Mol Biochem Parasitol 2010; 172:19-30. [DOI: 10.1016/j.molbiopara.2010.03.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2009] [Revised: 03/09/2010] [Accepted: 03/15/2010] [Indexed: 01/06/2023]
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21
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Mysliwy J, Dingley AJ, Stanisak M, Jung S, Lorenzen I, Roeder T, Leippe M, Grötzinger J. Caenopore-5: the three-dimensional structure of an antimicrobial protein from Caenorhabditis elegans. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2010; 34:323-330. [PMID: 19917307 DOI: 10.1016/j.dci.2009.11.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2009] [Revised: 11/03/2009] [Accepted: 11/04/2009] [Indexed: 05/28/2023]
Abstract
The caenopore-5 protein encoded by the spp-5 gene is one of the 33 caenopores identified in Caenorhabditis elegans and is a pore-forming peptide which plays an important role in the elimination of Escherichia coli ingested by the worm. Thus, caenopore-5 appears to contribute to the nutrition of the worm while simultaneously protecting the organism against pathogens. Here, three-dimensional heteronuclear NMR spectroscopy was used to solve the solution structure of caenopore-5. The NMR data revealed that two conformers of caenopore-5 exist in solution which differ by the isomerization of the peptide bond of Pro-81. The overall structure of the two caenopore-5 conformers consists of five amphiphatic helices connected by three disulfide bonds. The five helices are arranged in a folded leaf which is the characteristic signature of the SAPLIP family. The structure presented here is the first of an effector protein of the defensive system elucidated for the well-known model organism C. elegans.
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Affiliation(s)
- Justyna Mysliwy
- Institute of Biochemistry, Christian-Albrechts-University Kiel, Olshausenstr. 40, 24098 Kiel, Germany
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22
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Cell-free synthesis and combinatorial selective 15N-labeling of the cytotoxic protein amoebapore A from Entamoeba histolytica. Protein Expr Purif 2009; 68:22-7. [DOI: 10.1016/j.pep.2009.06.017] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2009] [Revised: 06/10/2009] [Accepted: 06/24/2009] [Indexed: 11/21/2022]
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23
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Mirelman D, Anbar M, Bracha R. Epigenetic transcriptional gene silencing in Entamoeba histolytica. IUBMB Life 2008; 60:598-604. [PMID: 18493998 DOI: 10.1002/iub.96] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The human intestinal pathogen Entamoeba histolytica has a number of virulence factors which can cause damage to the host. Transcriptional silencing of the gene coding for one of its major toxic molecules, the amoebapore (Ehap-a), occurred following the transfection of amoebic trophozoites with a plasmid containing the 5' promoter region of Ehap-a as well as a truncated segment of a neighboring, upstream SINE1 element that is transcribed from the opposite strand. Silencing was dependent on the presence of the truncated SINE1 sequences. Small amounts of short (approximately 140 n), ssRNA molecules with homology to SINE1 were detected in the silenced amoeba but no siRNA. The silenced Ehap-a gene domain had a chromatin modification indicating transcriptional inactivation without any DNA methylation. Removal of the plasmid did not restore transcription of Ehap-a. Transcription analysis by microarrays revealed that a number of additional genes were silenced and some were also up-regulated. Transfections of amoeba which already had a silenced Ehap-a, with a plasmid containing a second gene ligated to the 5' upstream region of Ehap-a, enabled the silencing, in-trans, of other genes of choice. The nonvirulent phenotype of the gene-silenced amoeba was demonstrated in various assays and the results suggest that they may have a potential use for vaccination.
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Affiliation(s)
- David Mirelman
- Department of Biological Chemistry, Weizmann Institute of Science, Rehovot 76100, Israel.
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24
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Sher D, Fishman Y, Melamed-Book N, Zhang M, Zlotkin E. Osmotically driven prey disintegration in the gastrovascular cavity of the green hydra by a pore‐forming protein. FASEB J 2007; 22:207-14. [PMID: 17679608 DOI: 10.1096/fj.07-9133com] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Pore-forming proteins (PFPs) are water-soluble proteins able to integrate into target membranes to form transmembrane pores. They are common determinants of bacterial pathogenicity and are often found in animal venoms. We recently isolated and characterized Hydralysins (Hlns), paralytic PFPs from the venomous green hydra Chlorohydra viridissima that are not found within the nematocytes, suggesting they are not involved in prey capture. The present study aimed to decipher the biological role of Hlns. Using in situ hybridization and immunohistochemistry, we show that Hlns are expressed by digestive cells surrounding the gastrovascular cavity (GVC) of Chlorohydra and secreted onto the prey during feeding. At biologically relevant concentrations, Hlns bind prey membranes and form pores, lysing the cells and disintegrating the prey tissue. Hlns are unable to bind Chlorohydra membranes, thus protecting the producing animal from the destructive effect of its own cytolytic protein. We suggest that osmotic disintegration of the prey within the GVC by Hlns, followed by phagocytosis and intracellular digestion, allows the soft-bodied green hydra to feed on hard, cuticle-covered prey while lacking the physical means to mechanically disintegrate it. Our results extend the biological significance of PFPs beyond the commonly expected offensive or defensive roles.
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Affiliation(s)
- Daniel Sher
- Department of Cell and Animal Biology, Silberman Institute of Life Sciences, The Hebrew University, Jerusalem 91904, Israel.
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25
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Kraus D, Peschel A. Molecular mechanisms of bacterial resistance to antimicrobial peptides. Curr Top Microbiol Immunol 2006; 306:231-50. [PMID: 16909924 DOI: 10.1007/3-540-29916-5_9] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Cationic antimicrobial peptides (CAMPs) are integral compounds of the antimicrobial arsenals in virtually all kinds of organisms, with important roles in microbial ecology and higher organisms' host defense. Many bacteria have developed countermeasures to limit the efficacy of CAMPs such as defensins, cathelicidins, kinocidins, or bacteriocins. The best-studied bacterial CAMP resistance mechanisms involve electrostatic repulsion of CAMPs by modification of cell envelope molecules, proteolytic cleavage of CAMPs, production of CAMP-trapping proteins, or extrusion of CAMPs by energy-dependent efflux pumps. The repertoire of CAMPs produced by a given host organism and the efficiency of microbial CAMP resistance mechanisms appear to be crucial in host-pathogen interactions, governing the composition of commensal microbial communities and the virulence of bacterial pathogens. However, all CAMP resistance mechanisms have limitations and bacteria have never succeeded in becoming fully insensitive to a broad range of CAMPs. CAMPs or conserved CAMP resistance factors are discussed as new mediators and targets, respectively, of novel and sustainable anti-infective strategies.
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Affiliation(s)
- D Kraus
- Cellular and Molecular Microbiology Division, Medical Microbiology and Hygiene Institute, University of Tübingen, Germany
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26
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Clarke DW, Niederkorn JY. The pathophysiology of Acanthamoeba keratitis. Trends Parasitol 2006; 22:175-80. [PMID: 16500148 DOI: 10.1016/j.pt.2006.02.004] [Citation(s) in RCA: 178] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2005] [Revised: 01/04/2006] [Accepted: 02/07/2006] [Indexed: 11/16/2022]
Abstract
Acanthamoeba keratitis is a sight-threatening infection of the ocular surface that is produced by several free-living amebae of the genus Acanthamoeba. Infection is usually initiated by Acanthamoeba-contaminated contact lenses and produces exquisite pain and ulceration of the ocular surface. The pathophysiology of this infection involves an intricate series of sequential events that includes the production of several pathogenic proteases that degrade basement membranes and induce cytolysis and apoptosis of the cellular elements of the cornea, culminating in dissolution of the collagenous corneal stroma. Targeting such proteases could lead to the development of vaccines that target the disease process rather than the pathogen itself.
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Affiliation(s)
- Daniel W Clarke
- Department of Ophthalmology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-9057, USA
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27
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Eichinger L, Noegel AA. Comparative genomics of Dictyostelium discoideum and Entamoeba histolytica. Curr Opin Microbiol 2006; 8:606-11. [PMID: 16125444 DOI: 10.1016/j.mib.2005.08.009] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2005] [Accepted: 08/15/2005] [Indexed: 11/18/2022]
Abstract
Amoebozoa represent one of the earliest branches from the last common ancestor of all eukaryotes and contain some of the most dangerous human pathogens. Two amoebozoan genomes -- from the model organism Dictyostelium discoideum and the human pathogen Entamoeba histolytica -- have been published this year. Owing to their high A+T content, both genomes were difficult to sequence. In addition to nine amoebozoan expressed sequence tag projects, efforts are underway for comparative sequencing of four additional Entamoeba species. The completed genome sequences of D. discoideum and E. histolytica revealed unusual telomere structures, a high percentage of repetitive elements and a remarkably high gene content that is close to the one of Drosophila melanogaster. Finally, both organisms are brilliant examples of the influence of the lifestyle of an organism on its genome.
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Affiliation(s)
- Ludwig Eichinger
- Centre for Biochemistry, Medical Faculty, University of Cologne, 50931 Köln, Germany
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28
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Kolter T, Winau F, Schaible UE, Leippe M, Sandhoff K. Lipid-binding Proteins in Membrane Digestion, Antigen Presentation, and Antimicrobial Defense. J Biol Chem 2005; 280:41125-8. [PMID: 16230343 DOI: 10.1074/jbc.r500015200] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Affiliation(s)
- Thomas Kolter
- Kekulé-Institut für Organische Chemie und Biochemie, D-53121 Bonn, Germany
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29
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Loftus BJ, Hall N. Entamoeba: still more to be learned from the genome. Trends Parasitol 2005; 21:453. [PMID: 16099723 DOI: 10.1016/j.pt.2005.08.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2005] [Revised: 06/23/2005] [Accepted: 08/03/2005] [Indexed: 11/24/2022]
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