270 likes | 391 Views
Virology review session: first midterm. By Philippe Perron Savard. Lecture 1. Don’t bother. No questions will be asked. Lecture 2: replication cycle. Cells provide: ribosomes, nucleotides & aa, ATP (energy), membranes. Consequences of virus replication on the cells: Diverts cell metabolism
E N D
Virology review session: first midterm By Philippe Perron Savard
Lecture 1 • Don’t bother. No questions will be asked.
Lecture 2: replication cycle • Cells provide: ribosomes, nucleotides & aa, ATP (energy), membranes. • Consequences of virus replication on the cells: • Diverts cell metabolism • Fill up the cells • Escape (lysis for example) • Apoptosis induction
Lecture 2: virus structure • Some viruses affect the behaviour of their host to improve transmission • A lot of viruses do not cause disease
Lecture 2: virus structure • Techniques used to detect and measure viruses: • Electron microscopy • Hemagglutination • Plaque assay • Foci formation • Replication cycle
Finding the pfu/ml • If a dilution (1/10000) is made and 1 ml of this dilution is plated: we get 50 plaques. • How do we solve this: • 50 plaques in 1 ml of the dilution= 50 pfu/ml in that dilution. • 50 pfu/ml * 10000 = 500 000 pfu/ml in the original solution.
Lecture 3: virus structure • One step growth curve • Baltimore classification • Basics of virus particles • Icosahedral and helical symmetry
Lecture 4: ssRNA phages • Gene regulation dependent mostly on RNA secondary structure • Replication Vs translation problem • Replication • Transcription of maturation gene
Lecture 5: ssDNA phage (X174) • Displays extensive overlapping in genes. How do we regulate transcription? • Concept of frames in transcription • Entry • Replication through rolling circle • Formation of the capsid
Different frame • ACG ATG GGG CCC TAT GCT • -1 AC GAT GGG GCC CTA TGC • -2 CGA TGG GGC CCT ATG CT • +1 TGG GGC CCT ATG CT • +2 GGG GCC CTA TGC
T7 phage • Entry and DNA winching by RNA pols from the host and the virus. • How it regulates transcription of its genes • How the T7 RNA pol functions • Problems with replication of linear dsDNA • pET vectors for protein expression
Lambda phage • Genome organisation • Understanding gene regulation is crucial • How do we repress the lytic cycle? • How do we decide between lysis or lysogeny • Integration into the bacterial genome and its regulation