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 11.16

RNA segments are coated with nucleocapsid proteins (NPs).

Two major envelope proteins:- Neuraminidase (NA)- Hemagglutinin (HA)

Influenza virus: note envelope

Figure 11.17

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

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Influenza Virus Entry

Figure 11.21

• Animation: Influenza Virus Replication

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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

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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. 19-11

CapMTH

Stopcodon

RNP MP CP

tRNA-likestructure

A viroid

Figure 6-6 Viroids: infective RNA.

Figure 6-7 Prion disease.