Pathogens.csv

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Author:
elplute
ID:
54240
Filename:
Pathogens.csv
Updated:
2010-12-07 23:38:40
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pathogens bacteria viruses HIV
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Pathogens
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  1. virulence
    quantitative measure of pathogenicity; includes infectious dose & transmission rate & severity/duration of symptoms
  2. alpha-hemolysis
    the ability of bacteria to produce partial hemolysis; produces a green color in bacterial medium
  3. beta-hemolysis
    the ability of bacteria to produce complete hemolysis
  4. gamma-hemolysis
    absence of hymolysis by bacterial toxins
  5. selective media
    suppresses the growth of certain kinds of bacteria
  6. differential media
    allow several types of bacteria to grow; addition of a nutrient or indicator allows differentiation between types of bacteria
  7. Gram staining
    1st step - primary staining with crystal violet; 2nd step - staining with Gram's iodine; 3rd step - decolorization with ethanol or acetone; 4th step - counterstaining with safranin; Gram-positive cells have thick layers of peptidoglycan in their cell walls and this stains purple with iodine
  8. transposons
    sequences of DNA that can transpose themselves to new positions within the genome of a single cell
  9. Gram negative vs. positive bacteria
    Gram-positive bacteria have a thick cell wall with multiples layers of peptidoglycan & teichoic acid & lipoteichoic acid; Gram-negative bacteria have a single layer of peptidoglycan & an outer membrane with porins & LPS as well as an inner membrane; selectively permeable outer membrane of Gram-negative bacteria provides additional layer of protection
  10. acid fast staining
    cells are stained & then treated with acid/ethanol to decolorize them & then counterstained; mainly used to identify acid-fast Mycobacteria (not decolorized with acid treatment)
  11. hemaglutanin
    a surface protein of influenza viruses that binds sialic acid on the surface of respiratory epithelial cells to allow the virus entry into the cell; mediates viral membrane fusion with host cell
  12. neuraminidase
    cleaves sialic acid and allows the release of the influenza virus from the host cell; targeted by Tamiflu to prevent viral exit from the host cell
  13. mycobacteria vs. mycoplasma
    mycobacteria have cell walls that contain mycolic acid; mycoplasma have no cell walls
  14. fimbriae
    also known as common pili; allow for twitch motility & tissue attachment
  15. bacterial capsule vs. endospore
    bacterial capsules surround bacteria & hide PAMPs to allow them to escape recognition & phagocytosis; Quellung reaction allows to visualize capsule; bacterial endospores are produced in response to severe nutrient limitation & allow bacteria to remain in a highly resistant latent state
  16. sites of action of antibacterial agents
    cell wall biosynthesis (Vancamycin & beta-lactams); ribosome (macrolides & tetracyclins & aminoglycosides); nucleic acids (quinolines); cell membrane (daptomycin); folate synthesis (sulfanomides & trimethoprim)
  17. beta-lactam
    inhibit transpeptidases that cross-link proteins to add stability to the cell wall
  18. Vancamycin
    binds to terminal d-Ala-d-Ala on bacterial cell wall side chains; prevents cross-linking of cell wall proteins
  19. types of bacterial genetic exchange
    conjugation - transfer of DNA from one bacterium to another via pili; transformation - uptake of DNA from the external environment; transduction - chromosomal DNA is transferred from one bacterium to another packaged in a virul capsid
  20. mechanisms of antibiotic resistance
    efflux pump; decreased entry; altered target site; enzymatic degradation; bypassing of pathway
  21. macrolide mechanism of action
    activity of macrolide on 50S ribosomal subunit prevents formation of protein chain
  22. aminoglycoside mechanism of action
    binding to 30S ribosomal subunit causes misreading of codon and leads to formation of a dysfunctional protein
  23. quinolones
    prevents uncoiling & reading of bacterial DNA
  24. bactericidal vs. bacteriostatic
    bactericidal therapies kill bacteria & should be used in meningitis (b/c CNS is immune privileged) or endocarditis (due to turbulent & avascular state of heart valve) or in neutropenic hosts; bacteriostatic therapies inhibit bacterial growth and are used in most all other circumstances
  25. MIC vs. MBC
    MIC = minimal inhibitory concentration (lowest concentration of antibiotic that produces no visible growth overnight); MBC = minimum bactericidal concentration (lowest concentration of antibiotic that kills 99.9% or more bacteria overnight)
  26. lectin
    a sugar-binding protein
  27. virulence factors
    molecules expressed and secreted by pathogens that allow them to successfully infect host cells & replicate
  28. superantigens
    "intact proteins with conserved binding sites for MHC II; cause non-specific activation of T cells; leads to a ""cytokine storm"" that effectively shuts down the immune system"
  29. lentivirus
    "retrovirus; HIV is a member; characterized by long incubation period; relatively large genome compared to simple retroviruses; ability to induce immune deficiencies and disorders of the hematopoietic and central nervous system; use of auxiliary proteins in excess to the three common structural proteins (Gag
  30. HIV co-receptors
    CCR5 (expressed on macrophages & dendritic cells * T cells); CXCR4 (expressed on T cells)
  31. dendritic cell HIV receptors
    C-type lectins such as DC-SIGN (CD-209); bind viral gp-120
  32. immune responses to HIV
    antibody-mediated response against gp120 & gp41 antigens on viral surface; cytotoxic T cell response against infected cells; neither detects latently infected cells in which the HIV genome has been successfully integrated
  33. strategies for HIV tropism
    tropism = ability to enter into cell; strategies = ongoing sequence evaluation; shielding of receptor binding site (occlusion)s; glycosylation
  34. components of HIV
    2 copies of RNA genome enclosed within a viral capsule; reverse transcriptase; viral integrase; viral envelope with gp120 and gp41; other enzymes
  35. alpha4beta7
    targets dendritic cells to site of HIV infection; up-regulated on dendritic cells by viral factors
  36. integrons
    mobile gene capture & disssemination systems; contain integrase & promotor (unlike transposons)

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