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

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. Poliovirus Structure 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

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. Poliovirus Replication Figure 11.13A

The flu virus has no geometric capsid. RNA genome is loosely contained by a shell of matrix proteins. Influenza Virus Structure Figure RNA segments are coated with nucleocapsid proteins (NPs). Two major envelope proteins: - Neuraminidase (NA) - Hemagglutinin (HA)

Influenza virus: note envelope

Figure The Genome of Influenza A Virus

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

Animation: Influenza Virus Entry into a Cell Click box to launch animation Influenza Virus Entry

Figure 11.21

Animation: Influenza Virus Replication Click box to launch animation Influenza Virus Replication

An icosahedral capsid houses the dsDNA genome. Herpes Simplex Virus Structure Capsid is surrounded by a protein tegument, which is contained within an envelope with spike proteins. Figure 11.31A

Figure 11.32

Animation: Herpes Virus Replication Click box to launch animation Herpes Virus Replication

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 Cap MTH Stop codon RNP MP CP tRNA-like structure

A viroid

Figure 6-6 Viroids: infective RNA.

Figure 6-7 Prion disease.