DOCSLIB.ORG

Ultrastructure and Development of the Female Reproductive Branches of Polysiphonia Harveyi

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Ultrastructure and Development of the Female Reproductive Branches of Polysiphonia Harveyi W&M ScholarWorks Dissertations, Theses, and Masters Projects Theses, Dissertations, & Master Projects 1981 Ultrastructure and development of the female reproductive branches of Polysiphonia harveyi Sharon Thompson Broadwater College of William & Mary - Arts & Sciences Follow this and additional works at: https://scholarworks.wm.edu/etd Part of the Botany Commons, and the Developmental Biology Commons Recommended Citation Broadwater, Sharon Thompson, "Ultrastructure and development of the female reproductive branches of Polysiphonia harveyi" (1981). Dissertations, Theses, and Masters Projects. Paper 1539625123. https://dx.doi.org/doi:10.21220/s2-j445-yw68 This Thesis is brought to you for free and open access by the Theses, Dissertations, & Master Projects at W&M ScholarWorks. It has been accepted for inclusion in Dissertations, Theses, and Masters Projects by an authorized administrator of W&M ScholarWorks. For more information, please contact [email protected]. ULTRASTRUCTURE AND DEVELOPMENT OF THE FEMALE REPRODUCTIVE BRANCHES OF POLYSIPHONIA HARVEYI A Thesis Presented To The Faculty of the Department of Biology The College of William and Mary in Virginia In Partial Fulfillment Of the Requirements for the Degree of Master of Arts by Sharon Thompson Broadwater 1981 APPROVAL SHEET This thesis is submitted in partial fulfillment of the requirements for the degree of Master of Arts * Sharon Thompson Broadwater Approved, May 1981 Joseph L. ~cott Stanton F. Hoegerman Ut'-cUU Lawrence L. Wiseman TABLE OF CONTENTS Page ACKNOWLEDGEMENTS........................................................................... iv LIST OF CHARTS AND DIAGRAMS . .............................................. v LIST OF FIGURES............................................................................... vi ABSTRACT.......................................................... v iii INTRODUCTION................................................................................................ 2 MATERIALS AND METHODS.................... 4 RESULTS ......................................................................................................... 5 DISCUSSION..................................................................................................... 17 LITERATURE CITED........................................................................................ 31 KEY TO ABBREVIATIONS................................................................................ 35 CHARTS AND DIAGRAMS................................................................................ 36 PLATES............................................................................................................. 39 VITA................................................................................................................. 48 i i i ACKNOWLEDGEMENTS I would like to express my sincere appreciation to Dr. Joseph L. Scott for his direction, enthusiasm and friendship during the course of this investigation. I also wish to recognize Dr.s Stanton F. Hoegerman and Lawrence L. Wiseman for c ritic a l reading of this manuscript and Kathleen L. Schornstein and Jewel P. Thomas for their companionship and patient instruction. LIST OF CHARTS AND DIAGRAMS Figure Page 1. Sequence of developmental events ................................... 36 2. Camera lucida drawing of procarp ................................... 37 3. PC type and position in procarp and cystocarp. 38 v LIST OF FIGURES Figure Page 1. Polysiphonia harveyi ................................................................ 39 2. P refertilization female branch .... .......................... 39 3. SEM of sexually mature procarp .................................. 39 4. Procarp with attached spermatia ........................................... 39 5. Cystocarps with releasing carpospores .............................. 39 6. Cystocarp Tabled with fluorescent stain. .................. 39 7. Prefertilization pericarp. ...................... ..... 40 8. Three-celled carpogonial branch. .................................. 40 9. Sexually mature procarp. ........ ...................... 40 10. Tip of trichogyne. ..................... 40 11. Prefertilization lateral sterile group ....... 41 12. Postfertilization lateral sterile group. ...... 41 13. Carpogonial branch past optimum age. ........ 41 14. Carpogonium with large vacuole ..................... 41 15. Crystalline structure of nucleolus .... 41 16. Hexagonal packing in nucleolus . .................................. 41 17. Trichogyne with attached spermatium .................................. 42 18. Spermatial nucleus within trichogyne ........ 42 19. Detaching trichogyne with plugging material. .... 42 20. Detaching trichogyne without plugging material . 42 v i ge Nucleus in postfertilization carpogonium ..................... 43 Second nucleus in carpogonium .............................................. 43 Channel of SER in carpogonial branch ............................. 43 Channel of SER in CB 2 . .................................................. 44 Pit connection between SU and CB-j. .................................. 44 Unfertilized deteriorating procarp ......... 44 Mature vegetative p it connection .... ..................... 45 Abbreviated connection between CB 2 and CB3 ................. 45 Semi-standard connection between AX and SU ................. 45 Abbreviated connection between SU and ST 2 ..................... 45 Young vegetative p it connection. .... ..................... 45 Pit connection with forming membrane ..................... 45 Young p it connection between CB 2 and CB3 ..................... 45 Disintegrating pit connection .............................................. 45 Female branch with direct fusion of SU and AU. 46 Postfertilization female branch .......................................... 46 Semi-standard connection between SU and CB-| ................. 46 Development of fusion cell .................................................. 47 v i i ABSTRACT P refertilization and immediate postfertilization development, as well as fertilization, in the female reproductive branch of Polysiphonia harveyi (Rhodomelaceae, Ceramiales) was documented for the firs t time with electron microscopy. EM results pertaining to p re fe rti 1ization morphology and development are consistant with those established earlier in lig h t microscopic studies but several new ultrastructural characteristics were discovered. The mature carpogonium was found to have double membrane-bound vacuoles of nuclear origin and the carpogonial nucleus was found to contain a nucleolus with a distinctive crystalline la ttice . Using a number of techniques, trichogynes were determined not to have a separate nucleus. Of greatest interest was the discovery of a highly structured channel of SER which extends uninterrupted, except for p it connections, through the carpogonial branch to the support cell. It is hypothesized that the channel acts to conduct the message of fe rtiliz a tio n from the carpogonium to the support ce ll. Very few observations were made on postfertilization branches but evidence of direct fusion between the carpogonium and auxiliary cell was fa irly conclusive. Special attention was given to the types of p it connections and their role in the development of the female reproductive branch. The name for the type of p it connection previously termed "transfer connection" has been changed to "abbreviated connection" since the results of this investigation do not fu lly support earlier reports of increased transport through these connections. Instead, abbreviated connections in the procarp appear to be a preformed structural weak­ ness whose disintegration allows rapid development of cytoplasmic continuity between cells. ULTRASTRUCTURE AND DEVELOPMENT OF THE FEMALE REPRODUCTIVE BRANCHES OF POLYSIPHONIA HARVEYI INTRODUCTION Development of a natural system of classification for the red algae is complicated by the wide variety of morphological character­ istics and complex life histories which they exhibit. Scagel (36) gives a succinct review of the steps leading to the present taxonomic treatment which divides the Rhodophyta into two classes: Bangio- phyceae and Floridiophyceae. The more advanced forms belong to the la tte r class and are divided into five orders according to pre- and po st-fe rtilization development of the female reproductive branch. Of the five orders, the Ceramiales is not only the most advanced but is also the best delimited (36, 11, 7). I t is separated from the other orders on the basis of having the auxiliary cell formed after fe rtiliz a tio n (11, 17). This order is composed of four families. The members of the Rhodomelaceae, the largest and most highly evolved of the four families, adhere very closely to a single line of female reproductive development (36). The present research was begun in order to present an account of female reproductive development in the Rhodomelaceae at the ultra- structural level. A number of light microscopic studies have been conducted previously (46, 36, 17, 26), but this study is the f ir s t u tiliz in g the electron microscope. Since female development is pivotal in systematizing the higher red algae, i t was fe lt that any 2 3 information might later be valuable in further taxonomic evaluation. In addition, i t was hoped that a comparison of results from lig h t microscopy with those from electron microscopy might answer some s t ill debated questions. It was also hoped that the study might illucidate some of the mechanisms
Load more

Recommended publications
  • History Department Botany
    THE HISTORY OF THE DEPARTMENT OF BOTANY 1889-1989 UNIVERSITY OF MINNESOTA SHERI L. BARTLETT I - ._-------------------- THE HISTORY OF THE DEPARTMENT OF BOTANY 1889-1989 UNIVERSITY OF MINNESOTA SHERI L. BARTLETT TABLE OF CONTENTS Preface 1-11 Chapter One: 1889-1916 1-18 Chapter Two: 1917-1935 19-38 Chapter Three: 1936-1954 39-58 Chapter Four: 1955-1973 59-75 Epilogue 76-82 Appendix 83-92 Bibliography 93-94 -------------------------------------- Preface (formerly the College of Science, Literature and the Arts), the College of Agriculture, or The history that follows is the result some other area. Eventually these questions of months ofresearch into the lives and work were resolved in 1965 when the Department of the Botany Department's faculty members joined the newly established College of and administrators. The one-hundred year Biological Sciences (CBS). In 1988, The overview focuses on the Department as a Department of Botany was renamed the whole, and the decisions that Department Department of Plant Biology, and Irwin leaders made to move the field of botany at Rubenstein from the Department of Genetics the University of Minnesota forward in a and Cell Biology became Plant Biology's dynamic and purposeful manner. However, new head. The Department now has this is not an effort to prove that the administrative ties to both the College of Department's history was linear, moving Biological Sciences and the College of forward in a pre-determined, organized Agriculture. fashion at every moment. Rather I have I have tried to recognize the attempted to demonstrate the complexities of accomplishments and individuality of the the personalities and situations that shaped Botany Department's faculty while striving to the growth ofthe Department and made it the describe the Department as one entity.
    [Show full text]
  • Understanding Cellular Signaling and Systems Biology with Precision: a Perspective from Ultrastructure and Organelle Studies In
    Available online at www.sciencedirect.com Current Opinion in ScienceDirect Systems Biology Understanding cellular signaling and systems biology with precision: A perspective from ultrastructure and organelle studies in the Drosophila midgut Chiwei Xu1, Maria Ericsson2 and Norbert Perrimon1,3 Abstract [1,2]. Interactions between these cell types are critical One of the aims of systems biology is to model and discover to maintaining tissue integrity and gut function. For properties of cells, tissues and organisms functioning as a example, ISCs proliferation and differentiation are system. In recent years, studies in the adult Drosophila gut have controlled by a complex network integrating autocrine provided a wealth of information on the cell types and their and paracrine signals [3,4]; hormones derived from EEs functions, and the signaling pathways involved in the complex regulate EC physiology; and EC-derived factors signal to interactions between proliferating and differentiated cells in the ISCs following gut damage. context of homeostasis and pathology. Here, we document and discuss how high-resolution ultrastructure studies of organelle Despite the body of knowledge about signaling in the gut, morphology have much to contribute to our understanding of how we are still far from understanding how different signals the gut functions as an integrated system. are processed and integrated inside the cell to orchestrate a particular cellular function. As much of the cell is Addresses organized in membrane-bound or membrane-free organ- 1
    [Show full text]
  • Ultrastructure of Secretory and Senescence Phase in Colleters of Bathysa Gymnocarpa and B
    Revista Brasil. Bot., V.33, n.3, p.425-436, jul.-set. 2010 Ultrastructure of secretory and senescence phase in colleters of Bathysa gymnocarpa and B. stipulata (Rubiaceae)1 EMILIO DE CASTRO MIGUEL2, DENISE ESPELLET KLEIN2,3, MARCO ANTONIO DE OLIVEIRA4 and MAURA DA CUNHA2,5 (received: December 11, 2008; accepted: June 10, 2010) ABSTRACT – (Ultrastructure of secretory and senescence phase in colleters of Bathysa gymnocarpa and B. stipulata (Rubiaceae)). Colleters are secretory structures formed by a parenchymatic axis with vascular bundles, bound by a layer of secretory palisade-like epidermis. Some studies regarding the structure of colleters have focused on secretory cells structure, but not distinguished the secretory and senescent phases. Generally, in mucilage-secreting cells such as colleters, the endoplasmic reticulum and Golgi apparatus are involved in secretion production and transport. In these study, colleters structure of Bathysa gymnocarpa K. Schum. and B. stipulata (Vell.) C. Presl. (Rubiaceae) were determined in two phases: a secretory phase and a senescence one. Samples were collected and processed by usual light and electron microscopy techniques. Studied colleters are constituted by an epidermal palisade layer and a central axis formed by parenchymatic cells with rare vascular traces. During the secretory phase, epidermal cells presented a dense cytoplasm, small vacuoles, enhanced rough and smooth endoplasmic reticulum, and a Golgi apparatus close to large vesicles. During the senescence phase epidermal cells presented a disorganized membrane system. No intact organelles or vesicles were observed. The outer cell wall exhibited similar layers to that observed during the secretory phase. The senescent phase is easily defined by the morphology of the colleters, but not well defined at subcellular level.
    [Show full text]
  • The Ultrastructure of Pathogenic Bacteria Under Different Ecological Conditions
    The Ultrastructure of Pathogenic Bacteria under Different Ecological Conditions The Ultrastructure of Pathogenic Bacteria under Different Ecological Conditions By Larisa Mikhailovna Somova The Ultrastructure of Pathogenic Bacteria under Different Ecological Conditions By Larisa Mikhailovna Somova This book first published 2020 Cambridge Scholars Publishing Lady Stephenson Library, Newcastle upon Tyne, NE6 2PA, UK British Library Cataloguing in Publication Data A catalogue record for this book is available from the British Library Copyright © 2020 by Larisa Mikhailovna Somova All rights for this book reserved. No part of this book may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, without the prior permission of the copyright owner. ISBN (10): 1-5275-4562-8 ISBN (13): 978-1-5275-4562-5 This book is dedicated to George Pavlovich Somov (1917–2009) The outstanding Russian epidemiologist and microbiologist, and founder of the Scientific School of Research Institute of Epidemiology and Microbiology in Vladivostok (Russia) “A life is good only when it is a continuous movement forward from the adolescence to the grave” TABLE OF CONTENTS Foreword .................................................................................................... ix Preface ....................................................................................................... xii Acknowledgements ..................................................................................
    [Show full text]
  • The Ultrastructure of a Typical Bacterial Cell the Bacterial Cell
    A.Kavitha Assistant professor Department of Botany RBVRR Womens college The Ultrastructure Of A Typical Bacterial Cell The Bacterial Cell This is a diagram of a typical bacterial cell, displaying all of it’s organelle. The Bacterial Cell This is what a bacterial cell looks like under an electron microscope. Bacteria come in a wide variety of shapes Perhaps the most elemental structural property of bacteria is their morphology (shape). Typical examples include: coccus (spherical) bacillus (rod-like) spiral(DNA-like) filamentous (elongated) Cell shape is generally characteristic of a given bacterial species, but can vary depending on growth conditions. Some bacteria have complex life cycles involving the production of stalks and appendages (e.g. Caulobacter) and some produce elaborate structures bearing reproductive spores (e.g. Myxococcus, Streptomyces). Bacteria generally form distinctive cell morphologies when examined by light microscopy and distinct colony morphologies when grown on Petri plates. Perhaps the most obvious structural characteristic of bacteria is (with some exceptions) their small size. For example, Escherichia coli cells, an "average" sized bacterium, are about 2 µm (micrometres) long and 0.5 µm in diameter, with a cell volume of 0.6–0.7 μm3.[1] This corresponds to a wet mass of about 1 picogram (pg), assuming that the cell consists mostly of water. The dry mass of a single cell can be estimated as 23% of the wet mass, amounting to 0.2 pg. About half of the dry mass of a bacterial cell consists of carbon, and also about half of it can be attributed to proteins. Therefore, a typical fully grown 1-liter culture of Escherichia coli (at an optical density of 1.0, corresponding to c.
    [Show full text]
  • J. Phycol. 53, 32–43 (2017) © 2016 Phycological Society of America DOI: 10.1111/Jpy.12472
    J. Phycol. 53, 32–43 (2017) © 2016 Phycological Society of America DOI: 10.1111/jpy.12472 ANALYSIS OF THE COMPLETE PLASTOMES OF THREE SPECIES OF MEMBRANOPTERA (CERAMIALES, RHODOPHYTA) FROM PACIFIC NORTH AMERICA1 Jeffery R. Hughey2 Division of Mathematics, Science, and Engineering, Hartnell College, 411 Central Ave., Salinas, California 93901, USA Max H. Hommersand Department of Biology, University of North Carolina at Chapel Hill, CB# 3280, Coker Hall, Chapel Hill, North Carolina 27599- 3280, USA Paul W. Gabrielson Herbarium and Department of Biology, University of North Carolina at Chapel Hill, CB# 3280, Coker Hall, Chapel Hill, North Carolina 27599-3280, USA Kathy Ann Miller Herbarium, University of California at Berkeley, 1001 Valley Life Sciences Building 2465, Berkeley, California 94720-2465, USA and Timothy Fuller Division of Mathematics, Science, and Engineering, Hartnell College, 411 Central Ave., Salinas, California 93901, USA Next generation sequence data were generated occurring south of Alaska: M. platyphylla, M. tenuis, and used to assemble the complete plastomes of the and M. weeksiae. holotype of Membranoptera weeksiae, the neotype Key index words: Ceramiales; Delesseriaceae; holo- (designated here) of M. tenuis, and a specimen type; Membranoptera; Northeast Pacific; phylogenetic examined by Kylin in making the new combination systematics; plastid genome; plastome; rbcL M. platyphylla. The three plastomes were similar in gene content and length and showed high gene synteny to Calliarthron, Grateloupia, Sporolithon, and Vertebrata. Sequence variation in the plastome Freshwater and Rueness (1994) were the first to coding regions were 0.89% between M. weeksiae and use gene sequences to address species-level taxo- M. tenuis, 5.14% between M.
    [Show full text]
  • Have Elevated Substitution Rates and 12 Extreme Gene Loss in the Plastid Genome 1 13 14
    1 2 DR. MAREN PREUSS (Orcid ID : 0000-0002-8147-5643) 3 DR. HEROEN VERBRUGGEN (Orcid ID : 0000-0002-6305-4749) 4 DR. GIUSEPPE C. ZUCCARELLO (Orcid ID : 0000-0003-0028-7227) 5 6 7 Article type : Regular Article 8 9 10 The organelle genomes in the photosynthetic red algal parasite Pterocladiophila 11 hemisphaerica (Florideophyceae, Rhodophyta) have elevated substitution rates and 12 extreme gene loss in the plastid genome 1 13 14 15 Maren Preuss2 16 School of Biological Sciences, Victoria University of Wellington, PO Box 600, Wellington, 17 6140, New Zealand 18 19 Heroen Verbruggen 20 School of BioSciences, University of Melbourne, Parkville, VIC 3010, Australia 21 and 22 Giuseppe C. Zuccarello 23 School of Biological Sciences, Victoria University of Wellington, PO Box 600, Wellington, 24 6140, New Zealand 25 26 27 Author Manuscript 28 Running title: Pterocladiophila organelle genomes 29 This is the author manuscript accepted for publication and has undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process, which may lead to differences between this version and the Version of Record. Please cite this article as doi: 10.1111/JPY.12996-20-002 This article is protected by copyright. All rights reserved 30 1 Received Accepted ___________ 31 2 Corresponding author: [email protected] 32 33 34 Editorial Responsibility: M. Coleman (Associate Editor) 35 36 37 ABSTRACT 38 Comparative organelle genome studies of parasites can highlight genetic changes that occur 39 during the transition from a free-living to a parasitic state. Our study focuses on a poorly 40 studied group of red algal parasites, which are often closely related to their red algal hosts and 41 from which they presumably evolved.
    [Show full text]
  • 758 the Ultrastructure of an Alloparasitic Red Alga Choreocolax
    PHYCOLOGIA 12(3/4) 1973 The ultrastructure of an alloparasitic red alga Choreocolax polysiphoniae I PAUL KUGRENS Department of Botany and Plant Pathology, Colorado State University, Fort Collins, Colorado 80521, U.S.A. AND JOHN A. WEST Department of Botany, University of California, Berkeley, California 94720, U.S.A. Accepted June 18, 1973 An alloparasite, Choreocolax polysipiloniae, apparently represents one of the most evolved parasitic red algae. Chlo�oplasts are highly redu�ed and consist of dOl!ble membrane limited organelles lacking any inter­ nal thylako!� developmen!. The unInucleate cells have thick walls, an absence of starch in cortical cells and larg� quantIties of starch In meduII ary cells. Host-para�ite connections are made by typical red algal pit con­ . nectIOns. G.eneral effects of t�e InfectIOn on the host .Include cell hypertrophy, decrease in floridean starch granules, dispersed cytoplasmiC matrIces, and contorsJOn of chloroplasts. Phycologia, 12(3/4): 175-186, 1973 Introduction of the host, Cryptopleura. Her decision was The paraSItIc red algae constitute a unique based on the similarity in reproductive struc­ 1?irou of organisms about which surprisingly tures between the host and parasite, and she � suggested bacteria as causal agents for such lIttle IS known, although their distinctive nature . has been recognized since the late nineteenth proliferatIons. Chemin (1937) also indicated century. There are approximately 40 genera, that bacteria might be causal agents since bac­ unknown numbers of species, and all are ex­ teria were isolated from surface-sterilized thalli clusively florideophycean, belonging to all of Callocolax neglectus. Observations on Lobo­ orders except the Nemaliales.
    [Show full text]
  • Identificação E Caraterização Da Flora Algal E Avaliação Do
    “A língua e a escrita não chegam para descrever todas as maravilhas do mar” Cristóvão Colombo Agradecimentos Aqui agradeço a todas as pessoas que fizeram parte deste meu percurso de muita alegria, trabalho, desafios e acima de tudo aprendizagem: Ao meu orientador, Professor Doutor Leonel Pereira por me ter aceite como sua discípula, guiando-me na execução deste trabalho. Agradeço pela disponibilidade sempre prestada, pelos ensinamentos, conselhos e sobretudo pelo apoio em altura mais complicadas. Ao Professor Doutor Ignacio Bárbara por me ter auxiliado na identificação e confirmação de algumas espécies de macroalgas. E ao Professor Doutor António Xavier Coutinho por me ter cedido gentilmente, diversas vezes, o seu microscópio com câmara fotográfica incorporada, o que me permitiu tirar belas fotografias que serviram para ilustrar este trabalho. Ao meu colega Rui Gaspar pelo interesse demonstrado pelo meu trabalho, auxiliando-me sempre que necessário e também pela transmissão de conhecimentos. Ao Sr. José Brasão pela paciência e pelo auxílio técnico no tratamento das amostras. Em geral, a todos os meus amigos que me acompanharam nesta etapa de estudante de Coimbra e que me ajudaram a sê-lo na sua plenitude, e em particular a três pessoas: Andreia, Rita e Vera pelas nossas conversas e pelo apoio que em determinadas etapas foram muito importantes e revigorantes. Às minhas últimas colegas de casa, Filipa e Joana, pelo convívio e pelo bom ambiente “familiar” que se fazia sentir naquela casinha. E como os últimos são sempre os primeiros, à minha família, aos meus pais e à minha irmã pelo apoio financeiro e emocional, pela paciência de me aturarem as “neuras” e pelo acreditar sempre que este objectivo seria alcançado.
    [Show full text]
  • Organellar Genome Evolution in Red Algal Parasites: Differences in Adelpho- and Alloparasites
    University of Rhode Island DigitalCommons@URI Open Access Dissertations 2017 Organellar Genome Evolution in Red Algal Parasites: Differences in Adelpho- and Alloparasites Eric Salomaki University of Rhode Island, [email protected] Follow this and additional works at: https://digitalcommons.uri.edu/oa_diss Recommended Citation Salomaki, Eric, "Organellar Genome Evolution in Red Algal Parasites: Differences in Adelpho- and Alloparasites" (2017). Open Access Dissertations. Paper 614. https://digitalcommons.uri.edu/oa_diss/614 This Dissertation is brought to you for free and open access by DigitalCommons@URI. It has been accepted for inclusion in Open Access Dissertations by an authorized administrator of DigitalCommons@URI. For more information, please contact [email protected]. ORGANELLAR GENOME EVOLUTION IN RED ALGAL PARASITES: DIFFERENCES IN ADELPHO- AND ALLOPARASITES BY ERIC SALOMAKI A DISSERTATION SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY IN BIOLOGICAL SCIENCES UNIVERSITY OF RHODE ISLAND 2017 DOCTOR OF PHILOSOPHY DISSERTATION OF ERIC SALOMAKI APPROVED: Dissertation Committee: Major Professor Christopher E. Lane Jason Kolbe Tatiana Rynearson Nasser H. Zawia DEAN OF THE GRADUATE SCHOOL UNIVERSITY OF RHODE ISLAND 2017 ABSTRACT Parasitism is a common life strategy throughout the eukaryotic tree of life. Many devastating human pathogens, including the causative agents of malaria and toxoplasmosis, have evolved from a photosynthetic ancestor. However, how an organism transitions from a photosynthetic to a parasitic life history strategy remains mostly unknown. Parasites have independently evolved dozens of times throughout the Florideophyceae (Rhodophyta), and often infect close relatives. This framework enables direct comparisons between autotrophs and parasites to investigate the early stages of parasite evolution.
    [Show full text]
  • Sample Preparation for Transmission Electron Microscopy (TEM) Support Film on TEM Grids Sectioning with Ultramicrotome Positi
    Sample preparation for Transmission electron microscopy (TEM) TEM is a microscopy technique whereby a beam of electrons is transmitted through an ultrathin specimen, interacting with the specimen as it passes through it. An image is formed from the electrons transmitted through the specimen, magnified and focused by an objective lens and appears on an imaging screen, a fluorescent screen in most TEMs, plus a monitor, or on a layer of imaging plate, or to be detected by a sensor such as a CCD camera. Biological materials contain large quantities of water. To be able to view it in the electron microscopy, the first stage in preparing is the fixation, one of the most important and most critical stages. We need to fixed it in a way that the ultrastructure of the cells or tissues remain as close to the living material as possible. The sample is then dehydrated through an acetone or ethanol series, passed through a “transition solvent” such as propylene oxide and then infiltrated and embedded in a liquid resin such as epoxy and LR White resin. After embedding the resin block is then thin sectioned by a process known as ultramicrotomy, sections of 50 ‐ 70 nm thickness are collected on metal mesh 'grids' and stained with electron dense stains before observation in the TEM. Sectioning the sample allows us to look at cross‐sections through samples to view internal (ultra)structure. Many modifications to the basic protocol can be applied to achieve many different goals, immunogold labeling for example; the in situ localization of specific tissue constituents using antibody and colloidal gold marker systems.
    [Show full text]
  • 2 the Structure and Ultrastructure of the Cell Gunther Neuhaus Institut Fu¨R Zellbiologie, Freiburg, Germany
    2 The Structure and Ultrastructure of the Cell Gunther Neuhaus Institut fu¨r Zellbiologie, Freiburg, Germany 2.1 Cell Biology . .........................40 2.2.7.6 Isolating Secondary Walls . 107 2.1.1 Light Microscopy . 43 2.2.8 Mitochondria . 109 2.1.2 Electron Microscopy . 45 2.2.8.1 Shape Dynamics and Reproduction . 110 2.2.8.2 Membranes and Compartmentalization in 2.2 The Plant Cell . .........................46 Mitochondria . 112 2.2.1 Overview . 46 2.2.9 Plastids . 113 2.2.2 The Cytoplasm . 50 2.2.9.1 Form and Ultrastructure of 2.2.2.1 The Cytoskeleton . 51 Chloroplasts . 114 2.2.2.2 Motor Proteins and Cellular Kinetic 2.2.9.2 Other Plastid Types, Starches . 116 Processes . 55 2.2.2.3 Flagella and Centrioles . 57 2.3 Cell Structure in Prokaryotes ............. 119 2.2.3 The Cell Nucleus . 59 2.3.1 Reproduction and Genetic Apparatus . 122 2.2.3.1 Chromatin . 60 2.3.2 Bacterial Flagella . 124 2.2.3.2 Chromosomes and Karyotype . 63 2.3.3 Wall Structures . 125 2.2.3.3 Nucleoli and Preribosomes . 64 2.2.3.4 Nuclear Matrix and Nuclear Membrane . 65 2.4 The Endosymbiotic Theory and the 2.2.3.5 Mitosis and the Cell Cycle . 66 Hydrogen Hypothesis . ............. 125 2.2.3.6 Cell Division . 73 2.4.1 Endocytobiosis . 126 2.2.3.7 Meiosis . 73 2.4.2 Origin of Plastids and Mitochondria by 2.2.3.8 Crossing-Over . 79 Symbiogenesis . 127 2.2.3.9 Syngamy . 79 2.2.4 Ribosomes .
    [Show full text]