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Chapter 13 VIRUSES

Chapter 13 VIRUSES. VIRUSES. SIZE - MEASURED IN NANOMETERS SUB-LIGHT MICROSCOPIC 3 MAJORS GROUPS ANIMAL PLANT BACTERIAL. COMMON CHARACTERISTICS. ALL ARE OBLIGATE INTRACELLULAR PARASITES ALL HAVE NO INDEPENDENT METABOLIC PATHWAYS FOR ENERGY SYNTHESIS

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Chapter 13 VIRUSES

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  1. Chapter 13 VIRUSES

  2. VIRUSES SIZE - MEASURED IN NANOMETERS SUB-LIGHT MICROSCOPIC 3 MAJORS GROUPS ANIMAL PLANT BACTERIAL

  3. COMMON CHARACTERISTICS ALL ARE OBLIGATE INTRACELLULAR PARASITES ALL HAVE NO INDEPENDENT METABOLIC PATHWAYS FOR ENERGY SYNTHESIS THEY ALL POSSESS ONLY ONE NUCLEIC ACID - RNA OR DNA NEVER BOTH THEY ALL HAVE A COMMON BASIC STRUCTURE SEEN IN 1942 WITH EM

  4. VARIABILITY OF VIRUSES TYPE OF NUCLEIC ACID MORPHOLOGY OF CAPSID

  5. POLYHEDRAL - ICOSAHEDRON

  6. HELICAL

  7. ENVELOPED VIRUSES

  8. INTRACELLULAR MULTIPLICATION CLASSIFICATION OF VIRUSES - INTERNATIONAL COMMITTEE ON TAXONOMY OF VIRUSES (ICTV) - 1966 TAXONOMIC LEVELS ORDER, FAMILY,GENUS, SPECIES

  9. Viral Taxonomy • Herpesviridae • Herpesvirus • Human herpes virus 1, HHV 2, HHV 3 • Retroviridae • Lentivirus • Human Immunodeficiency Virus 1, HIV 2

  10. 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

  11. LIFE CYCLES OF VIRUSES

  12. THE LYTIC CYCLE AND THE LYSOGENIC CYCLE Lytic cycle: Phage causes lysis and death of host cell Lysogenic cycle: Prophage DNA incorporated in host DNA

  13. 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

  14. THE LYTIC CYCLE

  15. ONE-STEP GROWTH CURVE

  16. THE LYSOGENIC CYCLE

  17. VARIETY OF ANIMAL VIRAL INFECTIONS - LYTIC OR LYSOGENIC VIRUSES?

  18. TRANSDUCTION

  19. HOW ANIMAL VIRUSES ENTER ANIMAL CELLS

  20. HOW ARE ANIMAL VIRUSES CULTURED IN THE LABORATORY?

  21. CELL CULTURE CLASSIFICATION OF MEDIA - LIVING AND NON-LIVING HOW CELL CULTURES ARE GROWN

  22. HOW ARE CELL CULTURES GROWN?

  23. In living animals or in embryonic eggs

  24. ANTIVIRAL AGENTS GENERALIZATIONS AMANTADINE A VARIETY OF NUCLEOSIDE ANALOGS ACYCLOVIR, AZT, 3TC, DDI, DDC PROTEASE INHIBITORS INTERFERONS

  25. AMANTADINE

  26. AVARIETY OF NUCLEOSIDE ANALOGS

  27. PROTEASE INHIBITORS AND INTERFERONS

  28. HEPATITIS VIRUSES HAV HBV HCV MODE OF TRANSMISSION CHRONICITY - CHRONIC OR ACUTE INFECTION TREATMENT/VACCINE

  29. UNCONVENTIONAL INFECTIVE AGENTS VIROIDS - 1967 SMALL CIRCULAR MOLECULES OF SINGLE STRANDED RNA BEST STUDIED VIROID CAUSES DISEASE IN POTATOES COMPOSED OF 359 NUCLEOTIDES 10X SMALLER THAN SMALLEST KNOWN VIRUS

  30. PRIONS INFECTIOUS SELF REPLICATING PROTEINS COMPOSED OF ABOUT 250 AMINO ACIDS 100X SMALLER THAN THE SMALLEST KNOWN VIRUS CAUSATIVE AGENT OF MAD COW DISEASE (BOVINE SPONGIFORM ENCEPHALOPATHY) AND TWO HUMAN DISEASES CREUTZFELDT - JAKOB DISEASE (CJD) KURU

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