Presentation is loading. Please wait.

Presentation is loading. Please wait.

Virus - Basics & News Taxonomy & Families

Similar presentations

Presentation on theme: "Virus - Basics & News Taxonomy & Families"— Presentation transcript:

1 Virus - Basics & News Taxonomy & Families
What is a virus ? Structure Genome Replication

2 A virus is a virus (lat: poison)
Replication: a replicating biochemical complex without its own metabolism requires metabolism of living host cell for replication Structure: Submicroscopic Size, nm (exception:orthopox) Genome: contains genetic information, DNA or RNA

3 Virus - sizes

4 Comparison of Size: Virus/Bakterium

5 An infectious virus particle ‘Virion‘
The genome (DNA or RNA) is always packed in a protein structure the ‘Capsid‘ The combine Capsid/Genomestructure: ‘Nukleocapsid‘ The capsid structure can be spherical (Icosaeder) or helical structure (Tubulus) Some viruses have additional structures: a lipid envelope engulfing the capsid

6 non enveloped Virus: contains only nucleic acid and protein
Tobacco mosaic virus: helical capsid Adenovirus: icosahedral capsid

7 ‘enveloped viruses‘ Herpes Simplex Virus Paramyxovirus
For enveloped viruses, the lipid envelope is always essential for infectivity. The envelops can be easily destoyed by ether & detergents

8 Spherical capsids have an icosahedral structure
An Icosahedron has 20 triangular surfaces and three axes of symmetry Picornavirus: 5-fold axes of smmetry animated X-Ray structure

9 Icosahedral capsids are built from capsomers:
Icosahedral capsids are built from capsomers: identical units of the same proteins X-Ray structure capsid of picornaviridae

10 The capsid surface of non enveloped viruse must carry
structures for binding to cellular receptors These both (non related) viruses bind to CAR but the binding structures look very different ‘Canyons‘ for binding to CAR (many enterovirus types) Fiber (‘Spikes‘) for binding to CAR (many adenovirus types)

11 Comparison: replication of virus vs. bacterium
obligat intrazellulär NIE auf Nährmedien, Agars usw. lebende Zellen erforderlich: Versuchstier Brutei Zellkultur Eklipse bzw. Latenzperiode, Adsorption, Penetration, Uncoating Proteinsynthese & Genomreplikation Assembly & Virusfreisetzung

12 Classical Concept of ICTV
taxonomy system: family/genus/species family names: ...-idae relevant for virus family: genome type (DNA, RNA; ds-, ss-, ) capsid structure (helical, icosahedral) enveloped/non enveloped

13 RNA viruses RNA-Virus


15 DNA viruses DNA-Virus

16 Baltimore System way of mRNA production (->Proteinsynthesis)
DNA Virus RNA Virus

Download ppt "Virus - Basics & News Taxonomy & Families"

Similar presentations

Ads by Google