DOCSLIB.ORG

This Thesis Has Been Submitted in Fulfilment of the Requirements for a Postgraduate Degree (E.G

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text

Load more

This thesis has been submitted in fulfilment of the requirements for a postgraduate degree (e.g. PhD, MPhil, DClinPsychol) at the University of Edinburgh. Please note the following terms and conditions of use: This work is protected by copyright and other intellectual property rights, which are retained by the thesis author, unless otherwise stated. A copy can be downloaded for personal non-commercial research or study, without prior permission or charge. This thesis cannot be reproduced or quoted extensively from without first obtaining permission in writing from the author. The content must not be changed in any way or sold commercially in any format or medium without the formal permission of the author. When referring to this work, full bibliographic details including the author, title, awarding institution and date of the thesis must be given. Protein secretion and encystation in Acanthamoeba Alvaro de Obeso Fernández del Valle Doctor of Philosophy The University of Edinburgh 2018 Abstract Free-living amoebae (FLA) are protists of ubiquitous distribution characterised by their changing morphology and their crawling movements. They have no common phylogenetic origin but can be found in most protist evolutionary branches. Acanthamoeba is a common FLA that can be found worldwide and is capable of infecting humans. The main disease is a life altering infection of the cornea named Acanthamoeba keratitis. Additionally, Acanthamoeba has a close relationship to bacteria. Acanthamoeba feeds on bacteria. At the same time, some bacteria have adapted to survive inside Acanthamoeba and use it as transport or protection to increase survival. When conditions are adverse, Acanthamoeba is capable of differentiating into a protective cyst. This study had three objectives. First, isolate and identify new FLA and Acanthamoeba strains. Second, identify encystation factors of Acanthamoeba . Third, identify and characterise new potential antimicrobial proteins produced by Acanthamoeba . The isolation of environmental amoebae was performed, and several strains of Acanthamoeba were identified from previously known genotypes. Also, two new species of FLA were identified: Allovahlkampfia minuta and Leptomyxa valladaresi . The dynamics of encystment were studied in different strains of Acanthamoeba . RNAseq was used to study gene expression during differentiation and identify differentially expressed genes. We identified different encystment factors including at least two encystment related proteases. A new antimicrobial zymogram was developed that identified antimicrobial proteins being secreted by Acanthamoeba . A 33 kDa protease was found to be able to lyse bacteria. We created DNA constructs encoding the protease and a lysozyme from Acanthamoeba for heterologous expression. The genes were successfully cloned. However, bacteria were not able to produce the proteins most probably due to their antimicrobial characteristics. Further studies are required regarding encystment and antimicrobial factors identified. Such experiments should help elucidate critical factors of Acanthamoeba ’s biology that could help treat several infections. Lay summary Free-living amoebae are microbes of ubiquitous distribution. Although they do not have a common evolutionary origin, all FLA are similar in their range of morphologies and locomotion. Some of these FLA are of particular importance as they are capable of producing infection. Acanthamoeba can produce a life-altering eye infection, among other less common diseases. In the environment, Acanthamoeba feeds on bacteria, and for this, it has developed different strategies to digest them. At the same time, some bacteria have adapted to be able to withstand Acanthamoeba , and survive and multiply inside of the amoeba. Bacteria that can survive inside Acanthamoeba can use it as a transport mechanism and as a haven from environmental challenges. Additionally, when conditions are adverse, Acanthamoeba can change its morphology and produce a protective cyst until conditions improve. This study had three objectives. First, isolate new amoebae. Second, identify critical factors in the production of the cyst by Acanthamoeba . Third, identify proteins used by Acanthamoeba to kill bacteria. Several Acanthamoeba organisms were isolated as well as two new species of FLA. In addition, different experiments to observe encystment dynamics were performed. From these, several factors for encystment were identified. Furthermore, two different proteins with potential to lyse bacteria were selected. One of the proteins was selected after the development of a new technique to observe bacterial lysis on a gel and the other protein through literature research. The genes for these proteins were isolated, but the proteins could not be produced in the laboratory. Although antimicrobial and encystment factors were identified, future studies are required to characterise them and have a deeper understanding of their functions and mechanisms. Such experiments should help elucidate critical factors of Acanthamoeba ’s biology that could help treat several infections. Own Work Declaration I declare that the thesis has been composed by myself and that the work has not be submitted for any other degree or professional qualification. I confirm that the work submitted is my own, except where explicitly stated otherwise or where work which has formed part of jointly-authored publications has been included. My contribution to these works have been explicitly indicated below. I confirm that appropriate credit has been given within this thesis where reference has been made to the work of others. Work presented in Chapter 5 and found in Appendix 1 was previously published in Experimental Parasitology as “Leptomyxa valladaresi n. sp. (Amoebozoa, Tubulinea, Leptomyxida), from Mount Teide, Tenerife, Spain” by Alvaro De Obeso Fernandez Del Valle, Jacob Lorenzo-Morales and Sutherland K. Maciver. This study was conceived by all of the authors. I carried out the molecular identification of the new organism. Work presented in Chapter 5 and found in Appendix 1 was previously published in Acta Protozoologica as “Allovahlkampfia minuta nov. sp., (Acrasidae, Heterolobosea, Excavata) a New Soil Amoeba at the Boundary of the Acrasid Cellular Slime Moulds” by Alvaro De Obeso Fernandez Del Valle and Sutherland K. Maciver. This study was conceived by all of the authors. I carried out the isolation and molecular identification of the new organism. Alvaro de Obeso Fernández del Valle January 2018 Acknowledgements ................................................................................................ i Abbreviations ......................................................................................................... ii Chapter 1 Introduction..................................................................................... 1 1.1 Amoebae .................................................................................................. 1 1.2 Free-living amoebae ................................................................................. 4 1.3 Acanthamoeba ......................................................................................... 4 Life cycle of Acanthamoeba .................................................................. 4 Morphology .......................................................................................... 6 Taxonomy ............................................................................................ 8 Isoenzyme profile .........................................................................10 Riboprinting .................................................................................10 18s rDNA .....................................................................................12 Cytochrome oxidase subunit I ......................................................13 Locomotion ..........................................................................................14 Feeding systems .................................................................................15 Ecology ...............................................................................................16 1.4 Bacteria-Amoebae interactions ................................................................17 Amoebae prey on bacteria ...................................................................17 Bacteria invade amoebae ....................................................................17 Mutualism ............................................................................................19 Bacterial infections aided by Acanthamoeba .......................................22 Legionella pneumophila .......................................................................22 1.5 Interactions between amoebae and other organisms ..............................23 Virus ....................................................................................................23 Fungi ...................................................................................................23 1.6 Diseases and importance ........................................................................24 Granulomatous amoebic encephalitis (GAE) .......................................24 Acanthamoeba rhinosinusitis ...............................................................26 Cutaneous acanthamebiasis or granulomatous dermatitis ...................26 Acanthamoeba keratitis (AK) ...............................................................26 Contact lens wear ........................................................................27
Recommended publications
  • Protozoan Fauna of Freshwater Habitats in South Dum Dum Municipality, North 24 Parganas, West Bengal

    Protozoan Fauna of Freshwater Habitats in South Dum Dum Municipality, North 24 Parganas, West Bengal

    Journal of Academia and Industrial Research (JAIR) Volume 3, Issue 3 August 2014 139 ISSN: 2278-5213 RESEARCH ARTICLE Protozoan Fauna of Freshwater Habitats in South Dum Dum Municipality, North 24 Parganas, West Bengal J. Chitra Protozoology Section, Lower Invertebrate Division, M Block, New Alipore, Kolkata-700053, India [email protected]; +91 98315 47265 ______________________________________________________________________________________________ Abstract Wetlands of South Dum Dum Municipality were focused to reveal the status of the planktonic protozoan fauna in detail. A total of 37 different sites were selected and plankton samples from these sites were collected. About 16 sp. of protozoa were identified from few localities from the present investigation. Eight species of rhizopoda belonged to 4 genera, 4 family (Pelomyxidae, Arcellidae, Centropyxidae and Difflugiidae) and 2 order (Pelobintida and Arcellinida), Four species of flagellate belongs to 2 genera, 1 family (Euglinidae) and 1 order (Euglenida), 4 species of ciliate belongs to 4 genera, 4 family (Colepidae, Vorticellidae, Euplotidae and Paramaeciidae), 2 order (Prorodontida and Peritrichida) and 2 suborder (Sporadotrichinia and Peniculina). Among 37 localities, protozoans were observed only in L2, L3, L8, L9, L12, L13, L15, L17, L18, L19, L21, L24, L26, L32, L33, L34 and L36 localities. Protozoan diversity and their abundance were noticed higher in L12, L18, L21, L26, L33 and L34 localities. Euglena viridis, E. acus, E. oxyuris and Phacus acumininata, Pelomyxa palustris, Vorticella companula were found to be higher in abundance and distribution. Keywords: South Dum Dum municipality, planktonic protozoan, Euglena viridis, abundance, distribution. Introduction Dumdum Park, Amarpalli, Telipukur, Nager Bazar, Protozoa are highly abundant in all aquatic habitats and Patipukur and Dum Dum were selected and the plankton greatly involved in food chain (Finlay, 1997).
  • Protozoologica Special Issue: Protists in Soil Processes

    Protozoologica Special Issue: Protists in Soil Processes

    Acta Protozool. (2012) 51: 201–208 http://www.eko.uj.edu.pl/ap ActA doi:10.4467/16890027AP.12.016.0762 Protozoologica Special issue: Protists in Soil Processes Review paper Ecology of Soil Eumycetozoans Steven L. STEPHENSON1 and Alan FEEST2 1Department of Biological Sciences, University of Arkansas, Fayetteville, Arkansas, USA; 2Institute of Advanced Studies, University of Bristol and Ecosulis ltd., Newton St Loe, Bath, United Kingdom Abstract. Eumycetozoans, commonly referred to as slime moulds, are common to abundant organisms in soils. Three groups of slime moulds (myxogastrids, dictyostelids and protostelids) are recognized, and the first two of these are among the most important bacterivores in the soil microhabitat. The purpose of this paper is first to provide a brief description of all three groups and then to review what is known about their distribution and ecology in soils. Key words: Amoebae, bacterivores, dictyostelids, myxogastrids, protostelids. INTRODUCTION that they are amoebozoans and not fungi (Bapteste et al. 2002, Yoon et al. 2008, Baudalf 2008). Three groups of slime moulds (myxogastrids, dic- One of the idiosyncratic branches of the eukary- tyostelids and protostelids) are recognized (Olive 1970, otic tree of life consists of an assemblage of amoe- 1975). Members of the three groups exhibit consider- boid protists referred to as the supergroup Amoebozoa able diversity in the type of aerial spore-bearing struc- (Fiore-Donno et al. 2010). The most diverse members tures produced, which can range from exceedingly of the Amoebozoa are the eumycetozoans, common- small examples (most protostelids) with only a single ly referred to as slime moulds. Since their discovery, spore to the very largest examples (certain myxogas- slime moulds have been variously classified as plants, trids) that contain many millions of spores.
  • Comparative Genomics of the Social Amoebae Dictyostelium Discoideum

    Comparative Genomics of the Social Amoebae Dictyostelium Discoideum

    Sucgang et al. Genome Biology 2011, 12:R20 http://genomebiology.com/2011/12/2/R20 RESEARCH Open Access Comparative genomics of the social amoebae Dictyostelium discoideum and Dictyostelium purpureum Richard Sucgang1†, Alan Kuo2†, Xiangjun Tian3†, William Salerno1†, Anup Parikh4, Christa L Feasley5, Eileen Dalin2, Hank Tu2, Eryong Huang4, Kerrie Barry2, Erika Lindquist2, Harris Shapiro2, David Bruce2, Jeremy Schmutz2, Asaf Salamov2, Petra Fey6, Pascale Gaudet6, Christophe Anjard7, M Madan Babu8, Siddhartha Basu6, Yulia Bushmanova6, Hanke van der Wel5, Mariko Katoh-Kurasawa4, Christopher Dinh1, Pedro M Coutinho9, Tamao Saito10, Marek Elias11, Pauline Schaap12, Robert R Kay8, Bernard Henrissat9, Ludwig Eichinger13, Francisco Rivero14, Nicholas H Putnam3, Christopher M West5, William F Loomis7, Rex L Chisholm6, Gad Shaulsky3,4, Joan E Strassmann3, David C Queller3, Adam Kuspa1,3,4* and Igor V Grigoriev2 Abstract Background: The social amoebae (Dictyostelia) are a diverse group of Amoebozoa that achieve multicellularity by aggregation and undergo morphogenesis into fruiting bodies with terminally differentiated spores and stalk cells. There are four groups of dictyostelids, with the most derived being a group that contains the model species Dictyostelium discoideum. Results: We have produced a draft genome sequence of another group dictyostelid, Dictyostelium purpureum, and compare it to the D. discoideum genome. The assembly (8.41 × coverage) comprises 799 scaffolds totaling 33.0 Mb, comparable to the D. discoideum genome size. Sequence comparisons suggest that these two dictyostelids shared a common ancestor approximately 400 million years ago. In spite of this divergence, most orthologs reside in small clusters of conserved synteny. Comparative analyses revealed a core set of orthologous genes that illuminate dictyostelid physiology, as well as differences in gene family content.
  • Ptolemeba N. Gen., a Novel Genus of Hartmannellid Amoebae (Tubulinea, Amoebozoa); with an Emphasis on the Taxonomy of Saccamoeba

    Ptolemeba N. Gen., a Novel Genus of Hartmannellid Amoebae (Tubulinea, Amoebozoa); with an Emphasis on the Taxonomy of Saccamoeba

    The Journal of Published by the International Society of Eukaryotic Microbiology Protistologists Journal of Eukaryotic Microbiology ISSN 1066-5234 ORIGINAL ARTICLE Ptolemeba n. gen., a Novel Genus of Hartmannellid Amoebae (Tubulinea, Amoebozoa); with an Emphasis on the Taxonomy of Saccamoeba Pamela M. Watsona, Stephanie C. Sorrella & Matthew W. Browna,b a Department of Biological Sciences, Mississippi State University, Mississippi State, Mississippi, 39762 b Institute for Genomics, Biocomputing & Biotechnology, Mississippi State University, Mississippi State, Mississippi, 39762 Keywords ABSTRACT 18S rRNA; amoeba; amoeboid; Cashia; cristae; freshwater amoebae; Hartmannella; Hartmannellid amoebae are an unnatural assemblage of amoeboid organisms mitochondrial morphology; SSU rDNA; SSU that are morphologically difficult to discern from one another. In molecular phy- rRNA; terrestrial amoebae; tubulinid. logenetic trees of the nuclear-encoded small subunit rDNA, they occupy at least five lineages within Tubulinea, a well-supported clade in Amoebozoa. The Correspondence polyphyletic nature of the hartmannellids has led to many taxonomic problems, M.W. Brown, Department of Biological in particular paraphyletic genera. Recent taxonomic revisions have alleviated Sciences, Mississippi State University, some of the problems. However, the genus Saccamoeba is paraphyletic and is Mississippi State, MS 39762, USA still in need of revision as it currently occupies two distinct lineages. Here, we Telephone number: +1 662-325-2406; report a new clade on the tree of Tubulinea, which we infer represents a novel FAX number: +1 662-325-7939; genus that we name Ptolemeba n. gen. This genus subsumes a clade of hart- e-mail: [email protected] mannellid amoebae that were previously considered in the genus Saccamoeba, but whose mitochondrial morphology is distinct from Saccamoeba.
  • Acanthamoeba Spp., Balamuthia Mandrillaris, Naegleria Fowleri, And

    Acanthamoeba Spp., Balamuthia Mandrillaris, Naegleria Fowleri, And

    MINIREVIEW Pathogenic and opportunistic free-living amoebae: Acanthamoeba spp., Balamuthia mandrillaris , Naegleria fowleri , and Sappinia diploidea Govinda S. Visvesvara1, Hercules Moura2 & Frederick L. Schuster3 1Division of Parasitic Diseases, National Center for Infectious Diseases, Atlanta, Georgia, USA; 2Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, Georgia, USA; and 3Viral and Rickettsial Diseases Laboratory, California Department of Health Services, Richmond, California, USA Correspondence: Govinda S. Visvesvara, Abstract Centers for Disease Control and Prevention, Chamblee Campus, F-36, 4770 Buford Among the many genera of free-living amoebae that exist in nature, members of Highway NE, Atlanta, Georgia 30341-3724, only four genera have an association with human disease: Acanthamoeba spp., USA. Tel.: 1770 488 4417; fax: 1770 488 Balamuthia mandrillaris, Naegleria fowleri and Sappinia diploidea. Acanthamoeba 4253; e-mail: [email protected] spp. and B. mandrillaris are opportunistic pathogens causing infections of the central nervous system, lungs, sinuses and skin, mostly in immunocompromised Received 8 November 2006; revised 5 February humans. Balamuthia is also associated with disease in immunocompetent chil- 2007; accepted 12 February 2007. dren, and Acanthamoeba spp. cause a sight-threatening infection, Acanthamoeba First published online 11 April 2007. keratitis, mostly in contact-lens wearers. Of more than 30 species of Naegleria, only one species, N. fowleri, causes an acute and fulminating meningoencephalitis in DOI:10.1111/j.1574-695X.2007.00232.x immunocompetent children and young adults. In addition to human infections, Editor: Willem van Leeuwen Acanthamoeba, Balamuthia and Naegleria can cause central nervous system infections in animals. Because only one human case of encephalitis caused by Keywords Sappinia diploidea is known, generalizations about the organism as an agent of primary amoebic meningoencephalitis; disease are premature.
  • A Revised Classification of Naked Lobose Amoebae (Amoebozoa

    A Revised Classification of Naked Lobose Amoebae (Amoebozoa

    Protist, Vol. 162, 545–570, October 2011 http://www.elsevier.de/protis Published online date 28 July 2011 PROTIST NEWS A Revised Classification of Naked Lobose Amoebae (Amoebozoa: Lobosa) Introduction together constitute the amoebozoan subphy- lum Lobosa, which never have cilia or flagella, Molecular evidence and an associated reevaluation whereas Variosea (as here revised) together with of morphology have recently considerably revised Mycetozoa and Archamoebea are now grouped our views on relationships among the higher-level as the subphylum Conosa, whose constituent groups of amoebae. First of all, establishing the lineages either have cilia or flagella or have lost phylum Amoebozoa grouped all lobose amoe- them secondarily (Cavalier-Smith 1998, 2009). boid protists, whether naked or testate, aerobic Figure 1 is a schematic tree showing amoebozoan or anaerobic, with the Mycetozoa and Archamoe- relationships deduced from both morphology and bea (Cavalier-Smith 1998), and separated them DNA sequences. from both the heterolobosean amoebae (Page and The first attempt to construct a congruent molec- Blanton 1985), now belonging in the phylum Per- ular and morphological system of Amoebozoa by colozoa - Cavalier-Smith and Nikolaev (2008), and Cavalier-Smith et al. (2004) was limited by the the filose amoebae that belong in other phyla lack of molecular data for many amoeboid taxa, (notably Cercozoa: Bass et al. 2009a; Howe et al. which were therefore classified solely on morpho- 2011). logical evidence. Smirnov et al. (2005) suggested The phylum Amoebozoa consists of naked and another system for naked lobose amoebae only; testate lobose amoebae (e.g. Amoeba, Vannella, this left taxa with no molecular data incertae sedis, Hartmannella, Acanthamoeba, Arcella, Difflugia), which limited its utility.
  • Molecular Detection of Human Parasitic Pathogens

    Molecular Detection of Human Parasitic Pathogens

    MOLECULAR DETECTION OF HUMAN PARASITIC PATHOGENS MOLECULAR DETECTION OF HUMAN PARASITIC PATHOGENS EDITED BY DONGYOU LIU Boca Raton London New York CRC Press is an imprint of the Taylor & Francis Group, an informa business CRC Press Taylor & Francis Group 6000 Broken Sound Parkway NW, Suite 300 Boca Raton, FL 33487-2742 © 2013 by Taylor & Francis Group, LLC CRC Press is an imprint of Taylor & Francis Group, an Informa business No claim to original U.S. Government works Version Date: 20120608 International Standard Book Number-13: 978-1-4398-1243-3 (eBook - PDF) This book contains information obtained from authentic and highly regarded sources. Reasonable efforts have been made to publish reliable data and information, but the author and publisher cannot assume responsibility for the validity of all materials or the consequences of their use. The authors and publishers have attempted to trace the copyright holders of all material reproduced in this publication and apologize to copyright holders if permission to publish in this form has not been obtained. If any copyright material has not been acknowledged please write and let us know so we may rectify in any future reprint. Except as permitted under U.S. Copyright Law, no part of this book may be reprinted, reproduced, transmitted, or utilized in any form by any electronic, mechanical, or other means, now known or hereafter invented, including photocopying, microfilming, and recording, or in any information storage or retrieval system, without written permission from the publishers. For permission to photocopy or use material electronically from this work, please access www.copyright.com (http://www.copyright.com/) or contact the Copyright Clearance Center, Inc.
  • Multiple Roots of Fruiting Body Formation in Amoebozoa

    Multiple Roots of Fruiting Body Formation in Amoebozoa

    GBE Multiple Roots of Fruiting Body Formation in Amoebozoa Falk Hillmann1,*, Gillian Forbes2, Silvia Novohradska1, Iuliia Ferling1,KonstantinRiege3,MarcoGroth4, Martin Westermann5,ManjaMarz3, Thomas Spaller6, Thomas Winckler6, Pauline Schaap2,and Gernot Glo¨ ckner7,* 1Junior Research Group Evolution of Microbial Interaction, Leibniz Institute for Natural Product Research and Infection Biology – Hans Kno¨ ll Institute (HKI), Jena, Germany 2Division of Cell and Developmental Biology, School of Life Sciences, University of Dundee, United Kingdom 3Bioinformatics/High Throughput Analysis, Friedrich Schiller University Jena, Germany 4CF DNA-Sequencing, Leibniz Institute on Aging Research, Jena, Germany 5Electron Microscopy Center, Jena University Hospital, Germany 6Pharmaceutical Biology, Institute of Pharmacy, Friedrich Schiller University Jena, Germany 7Institute of Biochemistry I, Medical Faculty, University of Cologne, Germany *Corresponding authors: E-mails: [email protected]; [email protected]. Accepted: January 11, 2018 Data deposition: The genome sequence and gene predictions of Protostelium aurantium and Protostelium mycophagum were deposited in GenBank under the Accession Numbers MDYQ00000000 and MZNV00000000, respectively. The mitochondrial genome of P. mycophagum was deposited under the Accession number KY75056 and that of P. aurantium under the Accession number KY75057. The RNAseq reads can be found in Bioproject Accession PRJNA338377. All sequence and annotation data are also available directly from the authors. The P. aurantium strain is deposited in the Jena Microbial Resource Collection (JMRC) under accession number SF0012540. Abstract Establishment of multicellularity represents a major transition in eukaryote evolution. A subgroup of Amoebozoa, the dictyos- teliids, has evolved a relatively simple aggregative multicellular stage resulting in a fruiting body supported by a stalk. Protosteloid amoeba, which are scattered throughout the amoebozoan tree, differ by producing only one or few single stalked spores.
  • BACE1 Function and Inhibition: Implications of Intervention in the Amyloid Pathway of Alzheimer’S Disease Pathology

    BACE1 Function and Inhibition: Implications of Intervention in the Amyloid Pathway of Alzheimer’S Disease Pathology

    Review BACE1 Function and Inhibition: Implications of Intervention in the Amyloid Pathway of Alzheimer’s Disease Pathology Gerald Koelsch CoMentis, Inc., South San Francisco, CA 94080, USA; [email protected] Received: 15 September 2017; Accepted: 10 October 2017; Published: 13 October 2017 Abstract: Alzheimer’s disease (AD) is a fatal progressive neurodegenerative disorder characterized by increasing loss in memory, cognition, and function of daily living. Among the many pathologic events observed in the progression of AD, changes in amyloid β peptide (Aβ) metabolism proceed fastest, and precede clinical symptoms. BACE1 (β-secretase 1) catalyzes the initial cleavage of the amyloid precursor protein to generate Aβ. Therefore inhibition of BACE1 activity could block one of the earliest pathologic events in AD. However, therapeutic BACE1 inhibition to block Aβ production may need to be balanced with possible effects that might result from diminished physiologic functions BACE1, in particular processing of substrates involved in neuronal function of the brain and periphery. Potentials for beneficial or consequential effects resulting from pharmacologic inhibition of BACE1 are reviewed in context of ongoing clinical trials testing the effect of BACE1 candidate inhibitor drugs in AD populations. Keywords: Alzheimer’s disease; amyloid hypothesis; BACE1; beta secretase; pharmacology 1. Introduction Alzheimer’s disease (AD) is a fatal progressive neurodegenerative disorder, slowly eroding memory, cognition, and functions of daily living, inevitably culminating in death from pneumonia and infectious diseases resulting from failure to thrive, loss of fine motor skills, and incapacitation. Treatment is limited to therapeutics that alleviate symptoms of memory loss, but are effective for a relatively short duration during and after which disease progression continues.
  • Testate Lobose Amoebae)

    Testate Lobose Amoebae)

    Palaeontologia Electronica palaeo-electronica.org Mediolus, a new genus of Arcellacea (Testate Lobose Amoebae) R. Timothy Patterson ABSTRACT Mediolus, a new arcellacean genus of the Difflugidae (informally known as the- camoebia, testate rhizopods, or testate lobose amoebae) differs from other genera of the family in having distinctive tooth-like inward oriented apertural crenulations and tests generally characterized by a variable number of hollow basal spines. R. Timothy Patterson. Ottawa-Carleton Geoscience Centre and Department of Earth Sciences, Carleton University, Ottawa, Ontario, K1S 5B6, Canada. [email protected] Keywords: Arcellacea; thecamoebian; testate lobose amoebae; Quaternary, new genus INTRODUCTION of the simple unilocular test (e.g., Bonnet, 1975; Medioli et al., 1987, 1990; Beyens and Meisterfeld, Arcellacea (also informally known as the- 2001), although some researchers have placed camoebians, testate amoebae, testate rhizopods, more emphasis on test composition (e.g., Ander- or testate lobose amoebae; Patterson et al., 2012) son, 1988). The proliferation of species descrip- are a diverse group of unicellular testate rhizopods tions within the Difflugia, often based on subtle test that occur in a wide array of aquatic and terrestrial differences, has resulted in considerable taxo- environments (Patterson and Kumar, 2002) from nomic confusion (Patterson and Kumar, 2002). the tropics to poles (Dalby et al., 2000). Although Researchers have often described new species most common in Quaternary sediments fossil based on regional interest, often with little consid- arcellaceans have been found preserved in sedi- eration of the previous literature or the systematic ments deposited under freshwater and brackish value of distinguishing characters (see discussions conditions spanning the Phanerozoic and into the in Medioli and Scott, 1983; Medioli et al., 1987; Neoproterozoic (Porter and Knoll, 2000; Van Ogden and Hedley, 1980; Tolonen, 1986; Bobrov Hengstum, 2007).
  • Protistology an International Journal Vol

    Protistology an International Journal Vol

    Protistology An International Journal Vol. 10, Number 2, 2016 ___________________________________________________________________________________ CONTENTS INTERNATIONAL SCIENTIFIC FORUM «PROTIST–2016» Yuri Mazei (Vice-Chairman) Welcome Address 2 Organizing Committee 3 Organizers and Sponsors 4 Abstracts 5 Author Index 94 Forum “PROTIST-2016” June 6–10, 2016 Moscow, Russia Website: http://onlinereg.ru/protist-2016 WELCOME ADDRESS Dear colleagues! Republic) entitled “Diplonemids – new kids on the block”. The third lecture will be given by Alexey The Forum “PROTIST–2016” aims at gathering Smirnov (Saint Petersburg State University, Russia): the researchers in all protistological fields, from “Phylogeny, diversity, and evolution of Amoebozoa: molecular biology to ecology, to stimulate cross- new findings and new problems”. Then Sandra disciplinary interactions and establish long-term Baldauf (Uppsala University, Sweden) will make a international scientific cooperation. The conference plenary presentation “The search for the eukaryote will cover a wide range of fundamental and applied root, now you see it now you don’t”, and the fifth topics in Protistology, with the major focus on plenary lecture “Protist-based methods for assessing evolution and phylogeny, taxonomy, systematics and marine water quality” will be made by Alan Warren DNA barcoding, genomics and molecular biology, (Natural History Museum, United Kingdom). cell biology, organismal biology, parasitology, diversity and biogeography, ecology of soil and There will be two symposia sponsored by ISoP: aquatic protists, bioindicators and palaeoecology. “Integrative co-evolution between mitochondria and their hosts” organized by Sergio A. Muñoz- The Forum is organized jointly by the International Gómez, Claudio H. Slamovits, and Andrew J. Society of Protistologists (ISoP), International Roger, and “Protists of Marine Sediments” orga- Society for Evolutionary Protistology (ISEP), nized by Jun Gong and Virginia Edgcomb.
  • What Substrate Cultures Can Reveal: Myxomycetes and Myxomycete-Like Organisms from the Sultanate of Oman

    What Substrate Cultures Can Reveal: Myxomycetes and Myxomycete-Like Organisms from the Sultanate of Oman

    Mycosphere 6 (3): 356–384(2015) ISSN 2077 7019 www.mycosphere.org Article Mycosphere Copyright © 2015 Online Edition Doi 10.5943/mycosphere/6/3/11 What substrate cultures can reveal: Myxomycetes and myxomycete-like organisms from the Sultanate of Oman Schnittler M1, Novozhilov YK2, Shadwick JDL3, Spiegel FW3, García-Carvajal E4, König P1 1Institute of Botany and Landscape Ecology, Ernst Moritz Arndt University Greifswald, Soldmannstr. 15, D-17487 Greifswald, Germany 2V.L. Komarov Botanical Institute of the Russian Academy of Sciences, Prof. Popov St. 2, 197376 St. Petersburg, Russia 3University of Arkansas, Department of Biological Sciences, SCEN 601, 1 University of Arkansas, Fayetteville, AR 72701, USA 4Royal Botanic Garden (CSIC), Plaza de Murillo, 2, Madrid, E-28014, Spain Schnittler M, Novozhilov YK, Shadwick JDL, Spiegel FW, García-Carvajal E, König P 2015 – What substrate cultures can reveal: Myxomycetes and myxomycete-like organisms from the Sultanate of Oman. Mycosphere 6(3), 356–384, doi 10.5943/mycosphere/6/3/11 Abstract A total of 299 substrate samples collected throughout the Sultanate of Oman were analyzed for myxomycetes and myxomycete-like organisms (MMLO) with a combined approach, preparing one moist chamber culture and one agar culture for each sample. We recovered 8 forms of Myxobacteria, 2 sorocarpic amoebae (Acrasids), 19 known and 6 unknown taxa of protostelioid amoebae (Protostelids), and 50 species of Myxomycetes. Moist chambers and agar cultures completed each other. No method alone can detect the whole diversity of myxomycetes as the most species-rich group of MMLO. A significant overlap between the two methods was observed only for Myxobacteria and some myxomycetes with small sporocarps.