DOCSLIB.ORG

Cell & Molecular Biology

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text

Load more

BSC ZO- 102 B. Sc. I YEAR CELL & MOLECULAR BIOLOGY DEPARTMENT OF ZOOLOGY SCHOOL OF SCIENCES UTTARAKHAND OPEN UNIVERSITY BSCZO-102 Cell and Molecular Biology DEPARTMENT OF ZOOLOGY SCHOOL OF SCIENCES UTTARAKHAND OPEN UNIVERSITY Phone No. 05946-261122, 261123 Toll free No. 18001804025 Fax No. 05946-264232, E. mail [email protected] htpp://uou.ac.in Board of Studies and Programme Coordinator Board of Studies Prof. B.D.Joshi Prof. H.C.S.Bisht Retd.Prof. Department of Zoology Department of Zoology DSB Campus, Kumaun University, Gurukul Kangri, University Nainital Haridwar Prof. H.C.Tiwari Dr.N.N.Pandey Retd. Prof. & Principal Senior Scientist, Department of Zoology, Directorate of Coldwater Fisheries MB Govt.PG College (ICAR) Haldwani Nainital. Bhimtal (Nainital). Dr. Shyam S.Kunjwal Department of Zoology School of Sciences, Uttarakhand Open University Programme Coordinator Dr. Shyam S.Kunjwal Department of Zoology School of Sciences, Uttarakhand Open University Haldwani, Nainital Unit writing and Editing Editor Writer Dr.(Ms) Meenu Vats Dr.Mamtesh Kumari , Professor & Head Associate. Professor Department of Zoology, Department of Zoology DAV College,Sector-10 Govt. PG College Chandigarh-160011 Uttarkashi (Uttarakhand) Dr.Sunil Bhandari Asstt. Professor. Department of Zoology BGR Campus Pauri, HNB (Central University) Garhwal. Course Title and Code : Cell and Molecular Biology (BSCZO 102) ISBN : 978-93-85740-54-1 Copyright : Uttarakhand Open University Edition : 2017 Published By : Uttarakhand Open University, Haldwani, Nainital- 263139 Contents Course 1: Cell and Molecular Biology Course code: BSCZO102 Credit: 3 Unit Block and Unit title Page number Number Block 1 Cell Biology or Cytology 1-128 1 Cell Type : History and origin. Prokaryotic and Eukaryotic cell. Difference 1-16 between Prokaryotic and Eukaryotic cell. 2 Plasma Membrane: History, Ultra structure, and chemical composition of plasma 17-31 membrane (Lamellar-models, micellar models and fluid mosaic model). Functions of plasma membrane . 3 Mitochondria : History and structure of mitochondria, biogenesis and functions of 32-44 mitochondria (Respiratory chain complex and Electron transport mechanism). 4 Endoplasmic Recticulum, Ribosome, Golgi Bodies: History, structure, functions 45-65 and importance. 5 Lysosomes, Centrioles, Microtubules : History, structure, functions and 66-79 Importance. 6 Nucleus : History, structure, functions and importance . 80 -91 7 Chromosomes : History, types and functions of chromosomes. Giant 92-104 chromosomes, Polytene chromosome and Lampbrush chromosome . 8 Cell Division: Mitosis (cell cycle stages, cytokinesis) Meiosis (reproductive cycle 105-128 stages, synoptonemal complex, recombination nodules). Comparison between meiosis and mitosis. BLOCK 2 Molecular Biology: 129-204 9 129-152 Structure and Type of DNA : Structure, functions and type of DNA, Watson And Crick’s structural model of DNA, chemical composition of DNA, replication of DNA and recombinant DNA. 10 Structure of RNA : Structure of RNA (primary, secondary and tertiary structure) and 153-172 types of RNA (transfer RNA, messenger RNA, ribosomal RNA). Biosynthesis of m- RNA, t-RNA. Function and importance of RNA. 11 Protein Synthesis and Regulation: Protein Synthesis, mechanism (initiation, 173-194 elongation and termination) of protein synthesis. Gene regulation (Operon hypothesis: regulator gene, promoter gene, operator gene, structural gene, repressor gene, co- repressor gene and inducer gene), regulation at transcription, regulation by gene arrangement and reversible phosphorylation, types of control mechanisms, regulation of gene activity in eukaryotes. 12 Genetic Code: Properties of genetic code, codons and anti codon, The Wobble 195-204 Hypothesis, Mutation and the triplet code. ZO-102 Cell & Molecular Biology Uttarakhand Open University UNIT: 1 CELL TYPE Contents 1.1 Objectives 1.2 Introduction 1.3 History and Origin 1.4 Basic Components of Prokaryotic and Eukaryotic Cells 1.4.1 Prokaryotic Cells 1.4.2 Eukaryotic Cells 1.4.3 Differences between Prokaryotic Cells and Eukaryotic Cells 1.5 Summary 1.6 Glossary 1.7 Self Assessment Questions and Possible Answers 1.7.1 Multiple Choice Questions 1.7.2 Very Short Questions 1.8 References and Suggested Readings 1.9 Terminal and Model Questions Page 1 ZO-102 Cell & Molecular Biology Uttarakhand Open University 1.1 Objectives Study of this unit will let the students to: • Define Prokaryotic cell; • Explain the structure of prokaryotic cell; • Write about Eukaryotic cell; • Elucidate the structure of Eukaryotic cell; • Differentiate between prokaryotic and eukaryotic cell. 1.2 Introduction A structure containing a mass of cytoplasm surrounded by semi-permeable membrane called plasma membrane is called a cell. It encloses cytoplasm, many cell organelles along with nucleus or nuclear material. On the basis of organization of membranes, variety and structure of cytoplasmic organelles and complexity of nuclear region, the cells are classified into two types: Prokaryotic cell and Eukaryotic cell. These terms were suggested by Hans Ris in 1960s . 1.3 History and Origin A cell was defined as “unit of biological activity delimited by a semi permeable membrane and capable of self-reproduction in a medium free of other living systems” by Loewy and Siekevitz (1963) . The study of cell has been made possible with the help of light microscope. Robert Hooke (1665) with the help of light microscope discovered that a section of cork is made up of small cavities surrounded by firm walls. He used the term “cell” for the first time to describe his investigations on the “texture of a piece of cork”. Later on A. Van Leeuwenhoek (1632-1723) observed various unicellular organisms and cells like bacteria, protozoan’s, red blood cells and sperm etc. He observed nucleus in some erythrocytes and all this was made possible with the improved microscopes. In 1809, Mirble M. stated that all plant tissues are composed of cells. In the same year, importance of cells in living organisms was described by J.B. Lamarck . Robert Brown in 1831 observed nucleus in certain plant cells. Mimosa cells were boiled in nitric acid by Dutrochet (1837) to separate the cells to conclude that all organic tissues are composed of globular cells, united by simple adhesive forces. “All living organism are composed of cells” was stated by Schwann, T. (1839) after examining a variety of animals and plant tissues. Page 2 ZO-102 Cell & Molecular Biology Uttarakhand Open University Fig. 1.1: A Bacterial Cell 1.4: BASIC COMPONENTS OF PROKARYOTIC AND EUKARYOTIC CELL 1.4.1 Prokaryotic Cells Prokaryotic cells are the most primitive cells and have simple structural organization. It has a single membrane system. They include bacteria, viruses, blue-green algae, mycoplasmas, rickettsias, spirochetes etc. Cyanobacteria or blue green algae are the largest and most complex prokaryote, in which photosynthesis of higher plants type have evolved. Prokaryotes are included in the kingdom Monera and the super kingdom Prokaryota . The Prokaryotes have the following characters: 1. The size of prokaryotic cells ranges between 1 to 10 µm. They occur in a variety of forms. 2. Prokaryotic cell consists of three main components: (I) Outer covering: It is composed of inner cell or plasma membrane, middle cell wall and outer slimy capsule. a. Cell membrane: Cell membrane made up of lipids and proteins, is thin and flexible and controls the movement of molecules across the cell. Respiratory enzymes are carried by it for energy releasing reactions. Mesosomes , the in-folds of plasma Page 3 ZO-102 Cell & Molecular Biology Uttarakhand Open University membrane bears respiratory enzymes and these are considered analogous to mitochondria of eukaryotic cells. Similarly, the pigments and enzymes molecules that absorb and convert the light into chemical energy in photosynthetic cells are also associated with the plasma membrane’s in-folds called photosynthetic lamella . These lamellae are analogous to the chloroplast of eukaryotic cells. Plasma membrane plays role in replication and division of nuclear material. Since the in-folds remain continuous with the cell membrane, they are not considered as separate compartments. Thus, prokaryotic cell is non-compartmentalized. b. Cell wall : It is a rigid or semi-rigid non-living structure that surrounds the cell membrane and its thickness ranges between 1.5 to 100 µm. Chemically it is composed of peptidoglycans . Some bacteria such as mycoplasmas lack cell wall. c. Slimy capsule: A gelatinous coat outside the cell wall is the slimy capsule. It is composed of largely of polysaccharides and sometimes it may have polypeptides and other compounds also. It protects the cell against desiccation, virus attacks, phagocytosis and antibiotics (II) Cytoplasm: Prokaryotic cytoplasm contains proteins, lipids, glycogen and inorganic ions along with enzymes for biosynthetic reactions and ribosomes, tRNA and mRNA for protein synthesis. Prokaryotic cytoplasm has some special features as follows: a. It lacks cell organelles like endoplasmic reticulum, mitochondria, Golgi apparatus, Centrosomes, vacuoles, Lysosomes, microfilaments, intermediate filaments and microtubules. b. The only cytoplasmic organelle found in prokaryotic cells is the ribosomes . They are smaller than eukaryotic ribosomes i.e., 70S and lie free in the cytoplasm. They form poly-ribosomes at the time of protein synthesis. They are the sites of protein synthesis. c. Like eukaryotic cells, the cytoplasm of prokaryotic cell does not
Recommended publications
  • Physical and Chemical Basis of Cytoplasmic Streaming

    Physical and Chemical Basis of Cytoplasmic Streaming

    Annual Reviews www.annualreviews.org/aronline .4n~t Rev. Plant Physiol 1981. 32:205-36 Copyright© 1981by AnnualReviews In~ All rights reserved PHYSICAL AND CHEMICAL BASIS OF CYTOPLASMIC ~7710 STREAMING Nobur6 Kamiya Department of Cell Biology, National Institute for Basic Biology, Okazaki, 444 Japan CONTENTS INTRODUCTION........................................................................................................ 206 SHUTI’LE STREAMINGIN THE MYXOMYCETEPLASMODIUM ................ 207 General...................................................................................................................... 207 ContractileProperties of the PlasmodialStrand ...................................................... 208 Activationcaused by stretching .................................................................................. 208 Activationcaused by loading .................................................................................... 209 Synchronizationof local ,hythms .............................................................................. 209 ContractileProteins .................................................................................................. 210 Plasmodiumactomyosin .......................................................................................... 210 Plusmodiummyosin ................................................................................................ 210 Plusmodiumactin.................................................................................................... 211
  • Overview of the Cytoskeleton from an Evolutionary Perspective

    Overview of the Cytoskeleton from an Evolutionary Perspective

    Downloaded from http://cshperspectives.cshlp.org/ on October 1, 2021 - Published by Cold Spring Harbor Laboratory Press Overview of the Cytoskeleton from an Evolutionary Perspective Thomas D. Pollard1 and Robert D. Goldman2 1Departments of Molecular Cellular and Developmental Biology, Molecular Biophysics and Biochemistry, and Cell Biology ,Yale University, New Haven, Connecticut 06520-8103 2Department of Cell and Molecular Biology, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611 Correspondence: [email protected] SUMMARY Organisms in the three domains of life depend on protein polymers to form a cytoskeleton that helps to establish their shapes, maintain their mechanical integrity, divide, and, in many cases, move. Eukaryotes have the most complex cytoskeletons, comprising three cytoskeletal poly- mers—actin filaments, intermediate filaments, and microtubules—acted on by three families of motor proteins (myosin, kinesin, and dynein). Prokaryotes have polymers of proteins ho- mologous to actin and tubulin but no motors, and a few bacteria have a protein related to intermediate filament proteins. Outline 1 Introduction—Overview of cellular 4 Overview of the evolution of the cytoskeleton functions 5 Conclusion 2 Structures of the cytoskeletal polymers References 3 Assembly of cytoskeletal polymers Editors: Thomas D. Pollard and Robert D. Goldman Additional Perspectives on The Cytoskeleton available at www.cshperspectives.org Copyright # 2018 Cold Spring Harbor Laboratory Press; all rights reserved; doi: 10.1101/cshperspect.a030288 Cite this article as Cold Spring Harb Perspect Biol 2018;10:a030288 1 Downloaded from http://cshperspectives.cshlp.org/ on October 1, 2021 - Published by Cold Spring Harbor Laboratory Press T.D. Pollard and R.D. Goldman 1 INTRODUCTION—OVERVIEW OF CELLULAR contrast, intermediate filaments do not serve as tracks for FUNCTIONS molecular motors (reviewed by Herrmann and Aebi 2016) but, rather, are transported by these motors.
  • Download the Abstract Book

    Download the Abstract Book

    1 Exploring the male-induced female reproduction of Schistosoma mansoni in a novel medium Jipeng Wang1, Rui Chen1, James Collins1 1) UT Southwestern Medical Center. Schistosomiasis is a neglected tropical disease caused by schistosome parasites that infect over 200 million people. The prodigious egg output of these parasites is the sole driver of pathology due to infection. Female schistosomes rely on continuous pairing with male worms to fuel the maturation of their reproductive organs, yet our understanding of their sexual reproduction is limited because egg production is not sustained for more than a few days in vitro. Here, we explore the process of male-stimulated female maturation in our newly developed ABC169 medium and demonstrate that physical contact with a male worm, and not insemination, is sufficient to induce female development and the production of viable parthenogenetic haploid embryos. By performing an RNAi screen for genes whose expression was enriched in the female reproductive organs, we identify a single nuclear hormone receptor that is required for differentiation and maturation of germ line stem cells in female gonad. Furthermore, we screen genes in non-reproductive tissues that maybe involved in mediating cell signaling during the male-female interplay and identify a transcription factor gli1 whose knockdown prevents male worms from inducing the female sexual maturation while having no effect on male:female pairing. Using RNA-seq, we characterize the gene expression changes of male worms after gli1 knockdown as well as the female transcriptomic changes after pairing with gli1-knockdown males. We are currently exploring the downstream genes of this transcription factor that may mediate the male stimulus associated with pairing.
  • Vocabulario De Morfoloxía, Anatomía E Citoloxía Veterinaria

    Vocabulario De Morfoloxía, Anatomía E Citoloxía Veterinaria

    Vocabulario de Morfoloxía, anatomía e citoloxía veterinaria (galego-español-inglés) Servizo de Normalización Lingüística Universidade de Santiago de Compostela COLECCIÓN VOCABULARIOS TEMÁTICOS N.º 4 SERVIZO DE NORMALIZACIÓN LINGÜÍSTICA Vocabulario de Morfoloxía, anatomía e citoloxía veterinaria (galego-español-inglés) 2008 UNIVERSIDADE DE SANTIAGO DE COMPOSTELA VOCABULARIO de morfoloxía, anatomía e citoloxía veterinaria : (galego-español- inglés) / coordinador Xusto A. Rodríguez Río, Servizo de Normalización Lingüística ; autores Matilde Lombardero Fernández ... [et al.]. – Santiago de Compostela : Universidade de Santiago de Compostela, Servizo de Publicacións e Intercambio Científico, 2008. – 369 p. ; 21 cm. – (Vocabularios temáticos ; 4). - D.L. C 2458-2008. – ISBN 978-84-9887-018-3 1.Medicina �������������������������������������������������������������������������veterinaria-Diccionarios�������������������������������������������������. 2.Galego (Lingua)-Glosarios, vocabularios, etc. políglotas. I.Lombardero Fernández, Matilde. II.Rodríguez Rio, Xusto A. coord. III. Universidade de Santiago de Compostela. Servizo de Normalización Lingüística, coord. IV.Universidade de Santiago de Compostela. Servizo de Publicacións e Intercambio Científico, ed. V.Serie. 591.4(038)=699=60=20 Coordinador Xusto A. Rodríguez Río (Área de Terminoloxía. Servizo de Normalización Lingüística. Universidade de Santiago de Compostela) Autoras/res Matilde Lombardero Fernández (doutora en Veterinaria e profesora do Departamento de Anatomía e Produción Animal.
  • Characterization of the Gene for the Microbody (Glycosomal) Triosephosphate Isomerase of Trypanosoma Brucei

    Characterization of the Gene for the Microbody (Glycosomal) Triosephosphate Isomerase of Trypanosoma Brucei

    The EMBO Journal vol.5 no.6 pp. 1291 -1298, 1986 Characterization of the gene for the microbody (glycosomal) triosephosphate isomerase of Trypanosoma brucei Bart W.Swinkels1, Wendy C.Gibson1, Klaas A.Osinga13, isomerase, EC 5.3.1.1) is particularly suitable for such com- Roel Kramer1, Gerrit H.Veeneman2, parative studies. The enzyme is well characterized (see Straus Jacques H.van Boom2 and Piet Borst1 et al., 1985); the amino acid sequence of TIMs from both 'Division of Molecular Biology, The Netherlands Cancer Institute, eukaryotic (Kolb et al., 1974; Corran and Waley, 1975; Alber Plesmanlaan 121, 1066 CX Amsterdam, and 20rganic Chemistry and Kawasaki, 1982; Maquat et al., 1985; Straus and Gilbert, Laboratory, State University Leiden, Gorlaeus Laboratory, PO Box 9502, 1985a) and prokaryotic (Artavanis-Tsakonas and Harris, 1980; 2300 RA Leiden, The Netherlands Pichersky et al., 1984) sources has been determined and high 3Present address: Research and Development, Gist-brocades NV, Postbus 1, resolution structures for the chicken (Banner et al., 1975) and 2600 MA Delft, The Netherlands yeast (Alber et al., 1981) proteins are available. This makes TIM Communicated by P.Borst suitable for deducing long-range evolutionary relationships. To determine how microbody enzymes enter microbodies, we TIM has previously been purified from Trypanosoma brucei are studying the genes for glycosomal (microbody) enzymes (Misset and Opperdoes, 1984) and crystals for X-ray diffraction in Trypanosoma brucei. Here we present our results for triose- have been obtained (Weirenga et al., 1984), allowing the elucida- phosphate isomerase (TIM), which is found exclusively in the tion of the 3-D structure of the enzyme.
  • Autophagy in Trypanosomatids

    Autophagy in Trypanosomatids

    Cells 2012, 1, 346-371; doi:10.3390/cells1030346 OPEN ACCESS cells ISSN 2073-4409 www.mdpi.com/journal/cells Review Autophagy in Trypanosomatids Ana Brennand 1,†, Eva Rico 2,†,‡ and Paul A. M. Michels 1,* 1 Research Unit for Tropical Diseases, de Duve Institute, Université catholique de Louvain, Avenue Hippocrate 74, postal box B1.74.01, B-1200 Brussels, Belgium; E-Mail: [email protected] 2 Department of Biochemistry and Molecular Biology, University Campus, University of Alcalá, Alcalá de Henares, Madrid, 28871, Spain; E-Mail: [email protected] † These authors contributed equally to this work. ‡ Present Address: Centre for Immunity, Infection and Evolution, Institute of Immunology and Infection Research, School of Biological Sciences, King’s Buildings, University of Edinburgh, West Mains Road, Edinburgh EH9 3JT, UK. * Author to whom correspondence should be addressed; E-Mail: [email protected]; Tel.: +32-2-7647473; Fax: +32-2-7626853. Received: 28 June 2012; in revised form: 14 July 2012 / Accepted: 16 July 2012 / Published: 27 July 2012 Abstract: Autophagy is a ubiquitous eukaryotic process that also occurs in trypanosomatid parasites, protist organisms belonging to the supergroup Excavata, distinct from the supergroup Opistokontha that includes mammals and fungi. Half of the known yeast and mammalian AuTophaGy (ATG) proteins were detected in trypanosomatids, although with low sequence conservation. Trypanosomatids such as Trypanosoma brucei, Trypanosoma cruzi and Leishmania spp. are responsible for serious tropical diseases in humans. The parasites are transmitted by insects and, consequently, have a complicated life cycle during which they undergo dramatic morphological and metabolic transformations to adapt to the different environments.
  • Phagocytosis Dynamics Depends on Target Shape

    Phagocytosis Dynamics Depends on Target Shape

    Biophysical Journal Volume 105 September 2013 1143–1150 1143 Phagocytosis Dynamics Depends on Target Shape Debjani Paul,†‡6* Sarra Achouri,†6 Young-Zoon Yoon,† Jurgen Herre,§ Clare E. Bryant,{ and Pietro Cicuta† † ‡ Cavendish Laboratory, University of Cambridge, Cambridge, United Kingdom; Department of Biosciences and Bioengineering, § { Indian Institute of Technology Bombay, Powai, Mumbai, India; Department of Medicine and Department of Veterinary Medicine, University of Cambridge, Cambridge, United Kingdom ABSTRACT A complete understanding of phagocytosis requires insight into both its biochemical and physical aspects. One of the ways to explore the physical mechanism of phagocytosis is to probe whether and how the target properties (e.g., size, shape, surface states, stiffness, etc.) affect their uptake. Here we report an imaging-based method to explore phagocytosis kinetics, which is compatible with real-time imaging and can be used to validate existing reports using fixed and stained cells. We measure single-event engulfment time from a large number of phagocytosis events to compare how size and shape of targets determine their engulfment. The data shows an increase in the average engulfment time for increased target size, for spherical particles. The uptake time data on nonspherical particles confirms that target shape plays a more dominant role than target size for phagocytosis: Ellipsoids with an eccentricity of 0.954 and much smaller surface areas than spheres were taken up five times more slowly than spherical targets. INTRODUCTION Macrophages can engulf a wide variety of targets, such as the degradation of phagosomal contents and the induction invading pathogens, dead cells, foreign airborne particles of the appropriate immune responses.
  • Actin Nucleator Spire 1 Is a Regulator of Ectoplasmic Specialization in the Testis Qing Wen1,Nanli1,Xiangxiao 1,2,Wing-Yeelui3, Darren S

    Actin Nucleator Spire 1 Is a Regulator of Ectoplasmic Specialization in the Testis Qing Wen1,Nanli1,Xiangxiao 1,2,Wing-Yeelui3, Darren S

    Wen et al. Cell Death and Disease (2018) 9:208 DOI 10.1038/s41419-017-0201-6 Cell Death & Disease ARTICLE Open Access Actin nucleator Spire 1 is a regulator of ectoplasmic specialization in the testis Qing Wen1,NanLi1,XiangXiao 1,2,Wing-yeeLui3, Darren S. Chu1, Chris K. C. Wong4, Qingquan Lian5,RenshanGe5, Will M. Lee3, Bruno Silvestrini6 and C. Yan Cheng 1 Abstract Germ cell differentiation during the epithelial cycle of spermatogenesis is accompanied by extensive remodeling at the Sertoli cell–cell and Sertoli cell–spermatid interface to accommodate the transport of preleptotene spermatocytes and developing spermatids across the blood–testis barrier (BTB) and the adluminal compartment of the seminiferous epithelium, respectively. The unique cell junction in the testis is the actin-rich ectoplasmic specialization (ES) designated basal ES at the Sertoli cell–cell interface, and the apical ES at the Sertoli–spermatid interface. Since ES dynamics (i.e., disassembly, reassembly and stabilization) are supported by actin microfilaments, which rapidly converts between their bundled and unbundled/branched configuration to confer plasticity to the ES, it is logical to speculate that actin nucleation proteins play a crucial role to ES dynamics. Herein, we reported findings that Spire 1, an actin nucleator known to polymerize actins into long stretches of linear microfilaments in cells, is an important regulator of ES dynamics. Its knockdown by RNAi in Sertoli cells cultured in vitro was found to impede the Sertoli cell tight junction (TJ)-permeability barrier through changes in the organization of F-actin across Sertoli cell cytosol. Unexpectedly, Spire 1 knockdown also perturbed microtubule (MT) organization in Sertoli cells cultured in vitro.
  • The Cytological Events and Molecular Control of Life Cycle Development of Trypanosoma Brucei in the Mammalian Bloodstream

    The Cytological Events and Molecular Control of Life Cycle Development of Trypanosoma Brucei in the Mammalian Bloodstream

    pathogens Review The Cytological Events and Molecular Control of Life Cycle Development of Trypanosoma brucei in the Mammalian Bloodstream Eleanor Silvester †, Kirsty R. McWilliam † and Keith R. Matthews * Institute for Immunology and Infection Research, Centre for Immunity, Infection and Evolution, School of Biological Sciences, King’s Buildings, University of Edinburgh, Charlotte Auerbach Road, Edinburgh EH9 3FL, UK; [email protected] (E.S.); [email protected] (K.R.McW.) * Correspondence: [email protected]; Tel.: +44-131-651-3639 † These authors contributed equally to this work. Received: 23 May 2017; Accepted: 22 June 2017; Published: 28 June 2017 Abstract: African trypanosomes cause devastating disease in sub-Saharan Africa in humans and livestock. The parasite lives extracellularly within the bloodstream of mammalian hosts and is transmitted by blood-feeding tsetse flies. In the blood, trypanosomes exhibit two developmental forms: the slender form and the stumpy form. The slender form proliferates in the bloodstream, establishes the parasite numbers and avoids host immunity through antigenic variation. The stumpy form, in contrast, is non-proliferative and is adapted for transmission. Here, we overview the features of slender and stumpy form parasites in terms of their cytological and molecular characteristics and discuss how these contribute to their distinct biological functions. Thereafter, we describe the technical developments that have enabled recent discoveries that uncover how the slender to stumpy transition is enacted in molecular terms. Finally, we highlight new understanding of how control of the balance between slender and stumpy form parasites interfaces with other components of the infection dynamic of trypanosomes in their mammalian hosts.
  • The Mechanics of Motility in Dissociated Cytoplasm

    The Mechanics of Motility in Dissociated Cytoplasm

    THE MECHANICS OF MOTILITY IN DISSOCIATED CYTOPLASM MICAH DEMBO Theoretical Biophysics, Theoretical Division, Los Alamos National Laboratory, Group T-10, Mail Stop K710, Los Alamos, New Mexico 87545 ABSTRACT We stimulate the dynamical behavior of dissociated cytoplasm using the Reactive Flow Model (Dembo, M., and F. Harlow, 1986, Biophys. J., 50:109-121). We find that for the most part the predicted dynamical behavior of the cytoplasm is governed by three nondimensional numbers. Several other nondimensional parameters, the initial conditions, and boundary conditions are found to have lesser effects. Of the three major nondimensional parameters, one (D#) controls the percentage of ectoplasm, the second (CO) controls the sharpness of the endoplasm-ectoplasm boundary, and the third (R#) controls the topological complexity of the endoplasm-ectoplasm distribution. If R# is very small, then the cytoplasm contracts into a single uniform mass, and there is no bulk streaming. If R# is very large, then the cytoplasmic mass breaks up into a number of clumps scattered throughout the available volume. Between these clumps the solution undergoes turbulent or chaotic patterns of streaming. Intermediate values of R# can be found such that the mass of cytoplasm remains connected and yet undergoes coherent modes of motility similar to flares (Taylor, D.L., J.S. Condeelis, P.L. Moore, and R.D. Allen, 1973, J. Cell Biol., 59:378-394) and rosettes (Kuroda, K., 1979, Cell Motility: Molecules and Organization, 347-362). INTRODUCTION (Dembo et al., 1986). Here we will consider two experi- in which chemical reaction is an essential The reactive flow model is a putative description of motile mental systems fluid part of the dynamics.
  • Kmcb-Abstract-Book-2019-Final

    Kmcb-Abstract-Book-2019-Final

    VIII April 27 – May 1, 2019 2 Eight Kinetoplastid Molecular Cell Biology Meeting April 27 – May 1, 2019 Hosted by the Marine Biological Laboratory Woods Hole, Massachusetts, USA The meeting was founded by George A.M. Cross in 2005 Organizers George A.M. Cross 2005-2011 Christian Tschudi 2013-2019 3 KMCBM 2019 Acknowledgements The organizer wishes to thank: The Program Committee Barbara Burleigh (Harvard T. H. Chan School of Public Health, Boston, USA) James D. Bangs (University at Buffalo, Buffalo, USA) Stephen M. Beverley (Washington University School of Medicine, St. Louis, USA) Keith R. Matthews (The University of Edinburgh, Edinburgh, Scotland, UK) The Staff at MBL: Paul Anderson and the MBL Housing and Conference Staff for registration and housing; All the IT AV Support staff and the staff in Sodexo Food Service at the MBL. Cover Design: Markus Engstler 4 KMCBM 2019 Program Saturday, April 27 02:00 – 05:00 Arrival, Registration and Poster Session A setup 04:00 – 06:30 Greeting and Dinner 07:00 – 09:00 Session I: VSG (chair: Mark Carrington) 09:00 – 11:00 Mixer Sunday, April 28 07:00 – 08:30 Breakfast 08:45 – 11:45 Session II: Biochemistry/Metabolism (chair: Ken Stuart) 12:00 – 01:30 Lunch 02:00 – 04:30 Session III: Cell Biology (chair: Kimberly Paul) 06:00 – 07:00 Dinner 07:00 – 09:00 POSTER PRESENTATIONS: Session A 09:00 – 11:00 Mixer & Poster A/B Changeover Monday, April 29 07:00 – 08:30 Breakfast 08:45 – 11:45 Session IV: Pathogenesis I (chair: Luisa Figueiredo) 12:00 – 01:30 Lunch 01:30 – 06:00 Free Time 06:00 – 07:00 Dinner 07:00
  • Chloroplast Incorporation and Long-Term Photosynthetic Performance Through the Life Cycle in Laboratory Cultures of Elysia Timid

    Chloroplast Incorporation and Long-Term Photosynthetic Performance Through the Life Cycle in Laboratory Cultures of Elysia Timid

    Chloroplast incorporation and long-term photosynthetic performance through the life cycle in laboratory cultures of Elysia timida (Sacoglossa, Heterobranchia) Schmitt et al. Schmitt et al. Frontiers in Zoology 2014, 11:5 http://www.frontiersinzoology.com/content/11/1/5 Schmitt et al. Frontiers in Zoology 2014, 11:5 http://www.frontiersinzoology.com/content/11/1/5 RESEARCH Open Access Chloroplast incorporation and long-term photosynthetic performance through the life cycle in laboratory cultures of Elysia timida (Sacoglossa, Heterobranchia) Valerie Schmitt1,2, Katharina Händeler2, Susanne Gunkel2, Marie-Line Escande3, Diedrik Menzel4, Sven B Gould2, William F Martin2 and Heike Wägele1* Abstract Introduction: The Mediterranean sacoglossan Elysia timida is one of the few sea slug species with the ability to sequester chloroplasts from its food algae and to subsequently store them in a functional state in the digestive gland cells for more than a month, during which time the plastids retain high photosynthetic activity (= long-term retention). Adult E. timida have been described to feed on the unicellular alga Acetabularia acetabulum in their natural environment. The suitability of E. timida as a laboratory model culture system including its food source was studied. Results: In contrast to the literature reporting that juvenile E. timida feed on Cladophora dalmatica first, and later on switch to the adult diet A. acetabulum, the juveniles in this study fed directly on A. acetabulum (young, non-calcified stalks); they did not feed on the various Cladophora spp. (collected from the sea or laboratory culture) offered. This could possibly hint to cryptic speciation with no clear morphological differences, but incipient ecological differentiation.