M2:T2: Animal viruses

• define animal virises

  • bind to specific host receptors
  • different tissues and organs express different cell surface proteins
  • uncoating occurs at cytoplasmic membrane
  • genome enters nucleus
• 3 types of cell entry

  1. direct peneration: attaches to surface and inject genome in host cell
  2. membrane fusion: envelope virus: occurs with receptors on cyto mem
  3. endocytosis: attaches to receptor on cell surface and membrane eats virus
• most animal viruses are

  envelope viruses
• different types of infection

  1. acute: lytic
  2. persistent: infect, multi and bus slowly
  3. latent: temperate
• role of virus in cancer

  • 20-25%
  • some carry and promote oncogene with interface with repression
  • this leads to cancer if virus insert into repressor genes
• Plaque assay

  clear zones that develop on lawns of host cells where viral infections occur
• 3 ways for detection

  1. electron microscopy
  2. NA analysis ie. PCE
  3. Serology
• different animal viruses

  1. ebola
  2. inflenza
  3. HIV
  4. SARS COV 2
• HIV

  • Single stranded RNA
  • retrovirus
  • once affects the host, it produces double stranded DNA
  • 10 Yrs dormat
  • affects the WBC
• stages of hiv

  1. attches
  2. fuses
  3. N capsid move into = uncoated
  4. release
  5. reverse transcritption
  6. DS DNA
• why are there different variations of flu

  1. due to plasticity of genome
  2. HA: hemaglutuin: binds to silic acid of host
  3. NA: neuramindase: cleaves to silic acid and destroys glycoproteins
• 2 variations of flu

  1. antigentic drift: minor chAnge to gene mutation
  2. antigentic shift: major change to gene reassortement