Access

You are not currently logged in.

Access your personal account or get JSTOR access through your library or other institution:

login

Log in to your personal account or through your institution.

If You Use a Screen Reader

This content is available through Read Online (Free) program, which relies on page scans. Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.

Electron microscopy of Eggplant mottled dwarf virus

Giovanni P. Martelli and Maria A. Castellano
Phytopathologia Mediterranea
Vol. 9, No. 1 (APRILE 1970), pp. 39-49
Stable URL: http://www.jstor.org/stable/42683999
Page Count: 11
  • Read Online (Free)
  • Subscribe ($19.50)
  • Cite this Item
Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.
Electron microscopy of Eggplant mottled dwarf virus
Preview not available

Abstract

The cytology of Eggplant and Tomato leaf tissues naturally and artificially infected with the agent of Eggplant mottled dwarf (EMDV) and the fine structure of virus particles were investigated with the electron microscope. Tissues were processed with both conventional procedures (primary aldehyde fixative followed by osmium tetroxide postfixation) and the uranyl soak method. Infection by EMDV did not appear to induce strikingly severe cytological changes in either of the hosts studied. Also the different fixing procedures caused cytological modifications of no consequence. Virus particles occurred in groups of several elements, sometimes arranged in paracrystalline aggregates, in perinuclear position between the inner and the outer lamella of the nuclear envelope. The particles were either bacilliform or bullet-shaped. The former occurred free in the perinuclear gaps and are considered to be mature virions whereas the bulletlike elements were, in most cases, attached to the nuclear membrane from which they were apparently budding. The fine structure of the particles revealed that they are probably made out of an inner component, helically arranged, likely with a nucleoprotein nature, surrounded by an envelope containing osmiophilic material, possibly lipids. Sono state studiate, al microscopio elettronico, la citologia dei tessuti fogliari di piante di Melanzana e di Pomodoro naturalmente e artificialmente infetti col virus del nanismo maculato della Melanzana (EMDV) e la struttura delle particelle virali. I tessuti sono stati trattati con metodi convenzionali (fissazione primaria con aldeide seguita da postfissazione con tetrossido di osmio) e col metodo dell'impregnazione con acetato di uranile. Le infezioni di EMDV non sembrano aver prodotto alterazioni citologiche di particolare gravità in nessuno degli ospiti considerati. Anche i vari metodi di fissazione non hanno praticamente influito sulla organizzazione delle strutture cellulari. Particelle virali in gruppi di numerosi elementi talora in aggregati paracristallini, sono state osservate in posizione perinucleare tra le lamelle della membrana del nucleo. Tali particelle hanno mostrato forma bacilliforme o di proiettile. Le prime sono apparse solitamente libere negli spazi perinucleari e sembrano poter essere considerate come particelle mature di EMDV. Le seconde, invece, vanno ritenute elementi virali immaturi anche in virtù del fatto che sono solitamente attaccate alla membrana nucleare dalla quale sembrano gemmare. Le particelle appaiono essere formate da un componente interno, probabilmente una nucleoproteina con disposizione elicoidale, circondato da un involucro contenente materiale osmiofilo, possibilmente lipidico. On a étudié au microscope électronique la cytologie des tissus foliares des plantes d'Aubergine et de Tomates naturellement et artificiellement infectées par le virus du nanisme tacheté de l'Aubergine (EMDV) et la structure des particules à virus. Les tissus ont été traités avec des méthodes conventionnelles (fixation primaire avec aldéhyde suivi par une post-fixation au tétraoxyde d'osmium) et avec la méthode de l'imprégnation par l'acétate d'uranium. Les infections de EMDV ne semblent pas avoir produit d'altérations cytologiques de particulière gravité sur aucun des hôtes pris en considération. Même les différentes méthodes de fixation n'ont pratiquement pas influencé l'organisation des structures cellulaires. Les particules de virus en groupes de nombreux éléments, quelquefois en agrégats paracristallins, ont été observées en position perinucléaire entre les lamelles de la membrane du noyau. De telles particules ont montré une forme de bacille ou de projectile. Les premières ont apparu généralement libres dans les espaces périnucléaires et il semble qu'on puisse les considérer comme des particules mûres de EMDV. Les secondes au contraire sont considérées comme des éléments à virus pas mûrs en vertu du fait qu'elles sont habituellement attachées à la membrane nucléaire de laquelle elles semblent bourgeonner. Les particules semblent formées d'un composant interne, probablement un nucléoprotéide à disposition hélicoïdale, entouré par une involucre qui contient matériel osmiophile probablement un lipide.

Page Thumbnails

  • Thumbnail: Page 
39
    39
  • Thumbnail: Page 
40
    40
  • Thumbnail: Page 
[41]
    [41]
  • Thumbnail: Page 
42
    42
  • Thumbnail: Page 
43
    43
  • Thumbnail: Page 
[44]
    [44]
  • Thumbnail: Page 
45
    45
  • Thumbnail: Page 
46
    46
  • Thumbnail: Page 
47
    47
  • Thumbnail: Page 
48
    48
  • Thumbnail: Page 
49
    49