BOLOGY 107 Lecture 36 Outline of Last Lecture I Viruses a Life cycle b Bacteriophages c Treatment d Retroviruses Rapid adaptation Outline of Current Lecture II Viruses a HIV III Viroids and Prions a Viroids b Prions Current Lecture Viruses 1 HIV a Invades immune system cells i White blood cells b Can exist as a provirus i Integrates DNA into the host genome c RTase is error prone i High mutation rate fast evolution ii By the time the immune system responds the virus cannot be recognized 1 Vaccines are useless become quickly drug resistance d Treatment target all steps i RTase inhibitors 1 Dideoxynucleotides prevent elongation lead to early termination a Example AZT has no 3 OH to continue chain ii Irreversible inhibition of enzyme 1 Protease inhibitors a Envelope proteins must be cut blocks protease to cut so no new virus forms 2 Fusion inhibitors These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute a Blocks the envelope from fusing with the host cell virus cannot get close enough to fuse 3 Integration inhibitors iii Problems with current treatments 1 High mutation leads to high resistance a Combated by administering a multi drug regimen making it difficult to adapt to all three the usual number in a combination 2 HIV drugs are designer drugs a Many cannot afford the regimens Viroids and Prions 2 Virods a Small circular naked ssRNA i No proteins ii 250 450 nucleotides iii Base pairs with itself b Found in plants i Cross cell wall and membrane freely ii Use mRNA transcription machinery to make copies of self 3 Prions a Infectious proteins i Misfolded versions of normal proteins ii No genetic material iii Very stable cannot be denatured by normal means b Occur from rare spontaneous misfolding i Mutations in the protein make this more likely ii Can be induced by another copy c Autocatalytic cause normal proteins to misfold i Aggregate and interfere with normal neuron function 1 Cells die leaving the brain looking like a sponge d Often degenerative brain diseases i Things like scrapie or Creutzfeld Jacob Disease e Can be trans species i Scrapie infected cows cows got mad cow disease humans ate infected beef humans got Creutzfeld Jacob Disease
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