Animal and Plant viruses
Plate Culture of Animal Viruses
Figure 6.33
Figure 6.20
Papillomavirus (DNA) Life Cycle
Figure 6.22
Picornavirus (RNA) Life Cycle
Figure 6.23
Figure 11.15
Poliovirus Structure
• The capsid is fundamentally icosahedral.
•
- Composed of three external proteins (VP1–3)
•
- VP4 protein subunits coat the interior and help
package the (+) strand RNA genome.
Figure 11.11B
• The poliovirus binds
to poliovirus
receptor (PVR)
through its VP2 and
VP3 subunits.
•
-A
conformational
change in VP1
allows insertion of
the genome into the
cytoplasm.
Figure 11.12
Poliovirus Replication
• In the cytoplasm, the RNA is translated to make three
large precursor peptides: P1–3.
•
- All three peptides are eventually cleaved by
proteases to generate 11 proteins.
Figure 11.13A
Influenza Virus Structure
• The flu virus has no geometric capsid.
• RNA genome is loosely contained by a shell of matrix
proteins.
Figure 11.16
RNA segments are coated with
nucleocapsid proteins (NPs).
Two major envelope proteins:
- Neuraminidase (NA)
- Hemagglutinin (HA)
Influenza virus: note envelope
The Genome of Influenza A Virus
Figure 11.17
• The key advantage of a segmented genome is that it
facilitates recombination between two strains
coinfecting the same cell.
•
- Instant new strain can evade the immune system.
Figure 11.18B
Influenza Virus Entry
• Animation: Influenza Virus Entry into a Cell
Click box to launch animation
Figure 11.21
Influenza Virus Replication
• Animation: Influenza Virus Replication
Click box to launch animation
Herpes Simplex Virus Structure
• An icosahedral capsid houses the dsDNA
genome.
Capsid is surrounded by a
protein tegument,
which is contained
within an envelope
with spike proteins.
Figure 11.31A
Figure 11.32
Herpes Virus Replication
• Animation: Herpes Virus Replication
Click box to launch animation
• Within a plant, the thick cell walls prevent a
lytic burst or budding out of virions.
•
- Instead, plant viruses are transmitted to
uninfected cells by plasmodesmata.
Figure 6.26
Fig. 19-11
tRNA-like
structure
Stop
codon
Cap
MTH
RNP
MP
CP
A viroid
Figure 6-6 Viroids: infective RNA.
Figure 6-7 Prion disease.