Virology
This presentation is the property of its rightful owner.
Sponsored Links
1 / 44

VIROLOGY PowerPoint PPT Presentation


  • 273 Views
  • Uploaded on
  • Presentation posted in: General

VIROLOGY. Allgemeine Virologie I. Introduction in Virology. History January 1796 vaccination against smallpox virus. Virus. Definition of virus Basic properties of viruses Morphology – Structures of virues Replication Classification. Bacteriophage. Basic Virology.

Download Presentation

VIROLOGY

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


Virology

VIROLOGY


Virology

Allgemeine Virologie I

Introduction in Virology

History

January 1796 vaccination against smallpox virus

Virus

  • Definition of virus

  • Basic properties of viruses

  • Morphology – Structures of virues

  • Replication

  • Classification

Bacteriophage

Basic Virology

Effect of viral replication CPE – Pathogenesis

  • Diseases

  • Immune response/ Immunopathogenesis

  • Diagnostic

  • Therapy

  • Prevention

Medical Virology


Virology

1796

E. Jenner

Vaccination against

smallpox


Virology

Edward Jenner (1749-1823):

European governments have officially encouraged or compelled the practise; and smallpox has ceased to be the almost universal scourge it was before Jenner's discovery.

Modern History Sourcebook


Early development of virology

Early Development of Virology

  • 1892:Dimitri Ivanowski

  • the causative agent of tobacco mosaic diseasewould pass through filters designed to remove bacteria

  • 1896: Beigerink---virus


Identified infectious agents since 1973

Identified infectious agents since 1973


Consequences of viral infections

Consequences of Viral Infections

  • Persistent disease

  • Fatal disease

  • Congenital disease

  • Contributory factor in cancer

Some are asymptomatic!


What are viruses

WHAT ARE VIRUSES

?

“A PIECE OFBAD NEWSWRAPPED UP IN A PROTEIN”


Virology

Virus

1. smallest infectious agents

2. one kind of nucleic acid (RNA or DNA)

3. intracellular parasites

4. assembly of the individual components

5. not usually respond to antibiotics


General properties of viruses

General Properties of Viruses


Size and shape

Size and Shape

Virion: the complete fully assembled virus, serves to transfer the viral nucleic acid

Range: from 20nm to 300nm in diameter

Shapes: spheres, rods, bullets, bricks, tadpoles


Size shape

Size & Shape

  • Virion :

    A complete infectious particle of virus

  • 20 nm ~ 300nm

  • spheres, rods, bullets or bricks

  • electron microscope, EM


Virology

A、Bacteriophage

( 65 ×95nm )

B、Adenovirus

(70nm )

Chlamydia

390nm

Rickettsia

450nm

C、Poliovirus

(30nm )

G

A

S.aureus

(1000nm)

D、JEV

( 40nm )

F

Cowpox

300×250nm

E、Protein

(10nm )

B

E

C

F、Influenza virus

( 100nm )

D

G、TMV


Virology

Shapes of viruses


Shapes of viruses spherical

Shapes of Viruses:Spherical


Virology

Shapes of Viruses :Rod-shaped


Virology

Shapes of Viruses :Brick-shaped


Tadpole shaped

Tadpole-shaped


Virology

Shapes of Viruses:Bullet-shaped


Virology

Shapes of Viruses :Filament


Viral structure

Viral Structure

nucleocapsid

(naked virus)

nucleic acid

enveloped virus

capsid

envelope


Virology

peplomere/spike

envelope

enveloped virus

capsomere

capsid

nucleocapsid(naked virus)

nucleic acid

Viral Structure


Virion structure

Virion structure

  • Core

  • Capsid

  • Envelop


A core

A. Core

  • The core consists of a nucleic acid genome.

  • The genome of the virus consists of either DNA or RNA.

    Function: It provide the information of reproduction, heredity and mutation.


B capsid

B. Capsid

  • The nucleic acid is surrounded by a protein coat called capsid, made up of subunits called capsomers.

  • The arrangement of capsomers gives the virus structure its geometric symmetry.

  • Three forms of symmetry in virus capsid: icosahedral, helical, complex forms


Icosahedral symmetry

Icosahedral Symmetry

  • 20 equilateral triangle faces

  • 12 vertices


Tobacco mosaic virus

helical

Tobacco Mosaic Virus

nucleic acid

protein


Complex symmetry

Complex Symmetry

POXVIRUS FAMILY


Virology

The functions of capsid:

  • protect the genetic material

  • mediate the attachment of the virus to specific receptors on the host cell surface

  • important antigens -- The host’s defense mechanisms (cellular or humoral) are directed against the viral antigenic epitopes.


C envelope

C.Envelope

  • The envelope is a lipoprotein membrane composed of lipid derived from the host cell membrane.

  • There are frequently glycoprotein in the form of spike on the surface, which attach to host cell receptors during the entry of the virus into the cell.

  • The envelope glycoprotein are also the principal antigens.


Chemical composition of viruses

Chemical Composition of Viruses


Chemical composition

Chemical Composition

[1] Viral protein

[2] Viral nucleic acid

[3] Viral lipid

[4] Viral glycoprotein


1 viral protein

[1] Viral protein

1.The structural proteins of viruses:

(1) Capsid protein

(2) Basic core protein

These proteins are necessary to package the nucleic acid within the capsid !


Virology

2. The non-structural proteins

The non-structural proteins are other proteins such as enzymes that are needed for the production of viral components but are not part of the virion.


Virology

Viral protein function:

1. Protect the nucleic acid

2. Take part in infection

3. Antigen


2 viral nucleic acid

[2] Viral nucleic acid

  • Viruses contain a single kind of nucleic acid, either DNA or RNA that encodes the genetic information necessary for replication of the virus.

  • The genome may be single-stranded or double-stranded, circular or linear, and segmented or non-segmented.


Virology

Six different classes can be distinguished, based on mechanisms of transcription.

1. +-dsDNA 2.+ssDNA

3. +- dsRNA 4.+ssRNA

5.–ssRNA 6.Retroviruses +ssRNA


Virology

  • The type of nucleic acid, its strandedness, and its size are mayjor characteristics used for classifying viruses into families.

  • The size of the DNA genome ranges from 3.2Kbp (hepadnaviruses) to 375Kbp (poxviruses).

  • The size of the viral RNA genome range from about 7Kb (picornaviruses) to 30Kb (coronaviruses).


3 viral lipid

[3] Viral lipid

  • A number of different viruses contain lipid envelope as part of their structure.

  • The lipid is acquired when the viral nucleocapsid buds through a cellular membrane in the course of maturation.


4 viral glycoprotein

[4] Viral glycoprotein

  • Viral envelope contain glycoprotein, and they are virus- encoded.

  • It is the surface glycoprotein of an enveloped virus that attach the virus particle to a target cell by interacting with a cellular receptor.

  • They are also important viral antigens.


Glycoprotein spikes

Glycoprotein Spikes

mediate the attachment of the virus to specific receptors on the host cell surface

important antigens


Virology

CYTOPLASM


Summary

Summary

  • Virion: fully assembled virus

  • Structure: core; capsid; envelop

  • Chemical composition: viral protein; nucleic acid; lipid; glycoprotein


  • Login