Theme 11
Virion
• Complete fully developed infec3ous viral par3cle
• Nucleic acid / capsid / envelope / spikes
• Viral species – a group of viruses sharing the same gene3c informa3on, structure and
ecological niche
Growing viruses
• Bacteriophages grown in bacteria – form plaques
• Animal viruses grown in – living animals, embryonated egg or cell cultures
Virus iden3fica3on
1. Cytopathic effects (cell cultures)
2. Serological tests – detect an3bodies present in pa3ents and use to iden3fy virus in
neutraliza3on tests / hemagglu3na3on and western blot
3. Nucleic acids – RFLPs(Restric3on fragment length polymorphism) Or PCR
(polymerase chain reac3on)
Viral mul3plica3on
• To mul3ply – invade host cell / take over hosts metabolic machinery
Mul3plica3on of bacteriophages
• Ly3c cycle – phage causes lysis and death of host cell
• Lysogenic cycle – prophage Dna into host DNA / phage conversion and specialized
transduc3on
Ly3c cycle
• AUachment – tail fibers
• Penetra3on – Phage Lysosome
• Biosynthesis – Phage Dna and proteins
• Matura3on – assembly
• Release – phage lysosome
Virion
• Complete fully developed infec3ous viral par3cle
• Nucleic acid / capsid / envelope / spikes
• Viral species – a group of viruses sharing the same gene3c informa3on, structure and
ecological niche
Growing viruses
• Bacteriophages grown in bacteria – form plaques
• Animal viruses grown in – living animals, embryonated egg or cell cultures
Virus iden3fica3on
1. Cytopathic effects (cell cultures)
2. Serological tests – detect an3bodies present in pa3ents and use to iden3fy virus in
neutraliza3on tests / hemagglu3na3on and western blot
3. Nucleic acids – RFLPs(Restric3on fragment length polymorphism) Or PCR
(polymerase chain reac3on)
Viral mul3plica3on
• To mul3ply – invade host cell / take over hosts metabolic machinery
Mul3plica3on of bacteriophages
• Ly3c cycle – phage causes lysis and death of host cell
• Lysogenic cycle – prophage Dna into host DNA / phage conversion and specialized
transduc3on
Ly3c cycle
• AUachment – tail fibers
• Penetra3on – Phage Lysosome
• Biosynthesis – Phage Dna and proteins
• Matura3on – assembly
• Release – phage lysosome
