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Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings PowerPoint ® Lecture Slide Presentation prepared by Christine L. Case M I C R O B I O L O G Y a n i n t r o d u c t i o n ninth edition TORTORA FUNKE CASE Part A 13 Viruses, Viroids, and Prions
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Viruses, Viroids, and Prions

Jan 19, 2016

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13. Viruses, Viroids, and Prions. How are they different?. Viruses. Contain DNA or RNA –sDNA, dDNA, sRNA, dRNA Contain a protein coat Some are enclosed by an envelope Some viruses have spikes Most viruses infect only specific types of cells in one host - PowerPoint PPT Presentation
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Page 1: Viruses, Viroids, and Prions

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings

PowerPoint® Lecture Slide Presentation prepared by Christine L. Case

M I C R O B I O L O G Ya n i n t r o d u c t i o n

ninth edition TORTORA FUNKE CASE

Part A13Viruses, Viroids,

and Prions

Page 2: Viruses, Viroids, and Prions

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings

Page 3: Viruses, Viroids, and Prions

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings

Contain DNA or RNA –sDNA, dDNA, sRNA, dRNA

Contain a protein coat

Some are enclosed by an envelope

Some viruses have spikes

Most viruses infect only specific types of cells

in one host

Host range is determined by specific host attachment

sites and cellular factors

Viruses

Page 4: Viruses, Viroids, and Prions

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings

Viruses

Figure 13.1

Page 5: Viruses, Viroids, and Prions

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings

Viruses

Figure 13.1

Page 6: Viruses, Viroids, and Prions

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings

Virion Size

Figure 13.1

Page 7: Viruses, Viroids, and Prions

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings

Helical Viruses

Figure 13.4a–b

Page 8: Viruses, Viroids, and Prions

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings

Helical Viruses

Figure 13.4a–b

Page 9: Viruses, Viroids, and Prions

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings

Polyhedral Viruses

Figure 13.2a–b

Page 10: Viruses, Viroids, and Prions

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings

Enveloped Viruses

Figure 13.3

Page 11: Viruses, Viroids, and Prions

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings

Complex Viruses

Figure 13.5a

Page 12: Viruses, Viroids, and Prions

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings

Viral Taxonomy

Family names end in -viridae.

Genus names end in -virus.

Viral species: A group of viruses sharing the same

genetic information and ecological niche (host).

Common names are used for species.

Subspecies are designated by a number.

Page 13: Viruses, Viroids, and Prions

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings

Viral Taxonomy

Herpesviridae

Herpesvirus

Human herpes virus

HHV-1, HHV-2, HHV-3

Retroviridae

Lentivirus

Human

immunodeficiency virus

HIV-1, HIV-2

Page 14: Viruses, Viroids, and Prions

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Figure 13.6

Page 15: Viruses, Viroids, and Prions

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings

Viruses

Figure 13.1

Page 16: Viruses, Viroids, and Prions

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings

Growing Viruses

Viruses must be

grown in living

cells.

Bacteriophages

form plaques on

a lawn of

bacteria.

Figure 13.6

Page 17: Viruses, Viroids, and Prions

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings

Growing Viruses

Animal viruses may

be grown in living

animals or in

embryonated eggs.

Figure 13.7

Page 18: Viruses, Viroids, and Prions

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings

Growing Viruses

Animal and plants viruses may be grown in cell culture.

Continuous cell lines may be maintained indefinitely.

Figure 13.8

Page 19: Viruses, Viroids, and Prions

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings

Virus Identification

Cytopathic effects

Serological tests

Detect antibodies against viruses in a patient.

Use antibodies to identify viruses in neutralization

tests, viral hemagglutination, and Western blot.

Nucleic acids

RFLPs

PCR

Page 20: Viruses, Viroids, and Prions

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings

Virus Identification

Figure 13.9

Page 21: Viruses, Viroids, and Prions

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings

Multiplication of Bacteriophages (Lytic Cycle)

Attachment: Phage attaches by tail fibers to host cell.

Penetration: Phage lysozyme opens cell wall, tail

sheath contracts to force tail core and DNA into cell.

Biosynthesis: Production of phage DNA and proteins.

Maturation: Assembly of phage particles.

Release: Phage lysozyme breaks cell wall.

Page 22: Viruses, Viroids, and Prions

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings

1

2

3

Figure 13.11, steps 1–3, 6–7

Page 23: Viruses, Viroids, and Prions

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings

4

Figure 13.11, steps 4–5, 8

Page 24: Viruses, Viroids, and Prions

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings

One-Step Growth Curve

Figure 13.10

Page 25: Viruses, Viroids, and Prions

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings

Lytic cycle: Phage causes lysis and death of host cell.

Lysogenic cycle: Prophage DNA incorporated in host

DNA.

Page 26: Viruses, Viroids, and Prions

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings

The Lysogenic Cycle

Figure 13.12

Page 27: Viruses, Viroids, and Prions

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings

2

3

4

5

6

Specialized Transduction

Figure 13.13

Page 28: Viruses, Viroids, and Prions

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings

Multiplication of Animal viruses

Attachment: Viruses attach to cell membrane.

Penetration by endocytosis or fusion.

Uncoating by viral or host enzymes.

Biosynthesis: Production of nucleic acid and proteins.

Maturation: Nucleic acid and capsid proteins assemble.

Release by budding (enveloped viruses) or rupture.

Page 29: Viruses, Viroids, and Prions

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings

Multiplication of Animal viruses

Page 30: Viruses, Viroids, and Prions

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings

Multiplication of Animal viruses

Page 31: Viruses, Viroids, and Prions

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings

Multiplication of Animal viruses

Page 32: Viruses, Viroids, and Prions

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings

Multiplication of Animal viruses

Page 33: Viruses, Viroids, and Prions

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings

PERSISTANCE VS. LATENT INFECTIONSs

Page 34: Viruses, Viroids, and Prions

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings

PERSISTANCE VS. LATENT INFECTIONSs

Page 35: Viruses, Viroids, and Prions

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings

PRIONS

Infectious Proteins

Page 36: Viruses, Viroids, and Prions

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings

VIROIDS

Infectionus RNA

Plant diseases so far