Upload
shawn-sparks
View
221
Download
0
Tags:
Embed Size (px)
Citation preview
Obsah
1) Virus as a entite
2) Introduction to virology
3) Composition of virion
4) Viral replication strategies
1) Viruses are the entities:
• Physical – shape, weight, size
• Biochemical – consisting of nucleid acids, proteins, phospholipids
• Biological
• Infectious agens
Virus as a biological entite
• Intracelullar obligate parasites +/-
• They have no ribosoms or energetic metabolism either -
• They have no binar division -
• They have a genom (RNA or DNA) +
• They are affected by biological evolution +
• They interact with living organisms +/-
2) Introduction to virology
Viruses of procaryots: bacteriofages, cyanofages, mycofages, viruses of protozoans, viruses of plants, animals, human Can we use
bacteriophages in medicine?
Probably not, but...
in ecology, research
We can
Subviral entities
• Viroids
Free chains of RNA, can cause deseases, mostly in plants
Virusoids – „parasites of virus“, hepatitis D
Briefly the history of virology
• Babylonia, Antient Greek – knowledge of rabies• Chine – very simple vaccination against small
pox • Egypt – hieroglyfs with people with polymyelitis• Breeding of plants• Vaccination – 18. century, England• L. Pasteur, vaccination against rabies virus
The 20. century
1892: Dimitrij Ivanovski – tabbaco virus desease
1898: Loeffler a Frosh - foot and mouth disease
1901: Carlos J. Finlay, Colonel W. Reed -virus of yellow fever – building of Panama canal
1911: Peyton Raus - virus and sarkomas
1915, 1917: Twort, dHérelle - bacteriofags
1935: W. Stanley – tabbaco virus desease was observed
Importance of virology
• Stopping of spreading of dangerous or pandemic incectious diseases
• Research of common diseases
• New treatment approach – gene therapy, nanotechnologies
• Metodical advances in molecular biology
• Informations in ecology and evolution biology
Important viral infection in the 20. century
• Influenza epidemies, most important 1919
• Dengue fever, tick born encephalitis
• Ebola virus
• Virus HIV, 80´s
The origin of viruses
regressive theory (viruses developed from cellular parasites)
origin in cellular RNA or DNA
coevolution of viruses from beggining of life origin in catalytical, autoreplicated RNA molecules
Methods of viral investigation
• Centrifugation – diferencial centrifugation, ultracentrifugation, electrone microscopy
• PCR, elektrophoresis, imunodetection, fluorescence microscopy
• Cell cultures, animal models, plaque assays
• Epidemiological methods, screening of population
3) Virion
Composition of virion:
• Nucleid acid (genom)
• Capsid
• Envelope (only enveloped viruses )
Nucleocapsid –virion, or capsid and genomu for coated viruses
http://hiv.boehringer-ingelheim.com/com/HIV/Information_material/Images.jsp
Viral nucleid acid
= viral genom: RNA/DNA, circular/linear, ss/ds, segmented, nonsegmented
Mostly 5 – 50 kb, 5 – 100 genes
Genes for • Structural genes – proteins of capsids, glykoproteins of
envelope, proteins of matrix• Non – structural genes – enzymes, oncogenes• Non – coding regulatory regions – promotors...• Genes ale often overlapped, are produced at clusters
and so on
Capsid is protein- made structure with genom in its inner
Composition of capsids:• Identical structural protein units - capsomers. • Capsomere is composed from structure viral
proteins
Capsid
Basic types: • ikozahedron consists of 20
triangular areas with 12 peaks (globular proteins)
• Helixal complex (viz cytoskelet), filium/bacillus viruses
• Cell like viruses
• Complicated structures of bacteriofags (head, flagellum, spikes)
Morfology of capsid:
Převzato z: www.biol.vt.edu
Viral envelope
• Phosfolipid bilayer with origin in cell membrane
• It contains glycoproteins – coded by viruses, they interacts with cell receptor
• It contains glycoproteins – coded by viruses, they interacts with cell receptor
Properties of viral envelope
• Primary potects the genom
• It helps to spread the viral genom
• Viral and cellular membranes can fused
Proteins of viral envelope - antigenes
Other components
• Virion can contain other proteins – enzymes, cellular proteins, viral chaperons
• Proteins used against imunne system
• Proteins for latency
4) Replication strategies of viruses
• DNA viruses – ssDNA, dsDNA
• RNA viruses – ssRNA, ds RNA
• Retroviruses – RNA transcribed to DNA and back to RNA
• Hepadnaviruses – DNA transcribed to RNA and back to DNA
RNA
(+)ssRNA (-)ssRNA dsRNA
DNA
ssDNA dsDNA
Viruses with reverse transcriptase
RetrovirusesRNA
Hepadnaviruses DNA
mRNAmRNA
dsDNA
HERPESVIRY
POXVIRY
I.I. ssDNA
II.II.
PARVOVIRY
dsDNA
dsRNA
III.III.
REOVIRY
IV.IV.(+)ssRNAPICORNAVIRY, TOGAVIRY
(–)ssRNA
(–)ssRNA
(+)ssRNA
V.V.ORTHOMYXOVIRYRHABDOVIRY
(+)ssRNARETROVIRY
Reverzní transkripceVI.VI.
dsDNAHEPADNAVIRY
VII.VII.