Bio 3400 - Lecture 5

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  1. Fts proteins
    • Filamentous temperature-senesitive proteins
    • FtsZ - Ring around centre
    • ZipA - Connects FtsZ to membrane
    • FtsA - Recruits other cytoplasmic proteins
    • FtsK - Mediates separation of chromosomes
  2. Min proteins
    Facilitate location of FtsZ
  3. MreB
    • Prokaryotic shape determining factor
    •  - Simple cytoskeleton (Bacteria and Archaea)
    •  - Not found in coccus
    •  - Loacalizes peptidoglycan synthesis
  4. Crescentin
    • Shape-determining protein produced by vibrio-shaped cells of Caulobacter crescentus
    •  - Found on concave surfaces
  5. Epicentre of cell wall growth
    • Cocci - From FtsZ ring
    • Rod-shapes - From points along length
  6. Bactoprenol
    • Carrier molecule that plays a major role in insertion of peptidoglycan precursors
    •  - Nonpolar, easy membrane passage
  7. Generation time equation
    • g = t/n
    • t = duration of exp. growth
    • n = No. of generations during exponential growth period
  8. Typical growth curve
    • 1. Slow growth at first while numbers increase
    • 2. Exponential growth while nutrients are present
    • 3. Stabilized growth as nutrients become limiting and waste builds up
    • 4. Death
  9. Culture types
    • Continuous
    • Chemostat
  10. Effects of too high or too low temperatures for a cell
    • Too low - Membrane gelling, slow transport
    • Too high - Protein denaturation, membrane collapse, thermal lysis
  11. Cold extremophiles
    • Psychrophiles - Very cold temperature optima
    • Psychrotolerant - Organisms that can grow at 0°C, though their optimum is somewhat higher
  12. Cold climate adaptations
    • More α helices than β sheets
    • More polar and less nonpolar residues
    • Decreased interactions between protein domains
    • Antifreeze proteins
    • Accumulation of compatible solutes
    • Upregulation of peptidoglycan synthesis
  13. Hot extremophiles
    • Thermophiles - Growth optima between 45°C and 80°C
    • Hyperthermophiles - Optima greater than 80°C
  14. Extreme-hot climate adaptations
    • Heat tolerant protein folding
    • Increased ionic bonds between acidic and basic residues
    • Di-inositol phosphate, diglycerol phosphate
  15. Bacterial adaptation to high heat
    Membranes rich in saturated fatty acids
  16. Archeal adaptation to high heat
    Lipid monolayer rather than bilayer
  17. Neutrophiles, Acidophiles and Alkaliphiles
    • Neutrophiles - pH 6-8
    • Acidophiles - pH <6; sensitive membranes
    • Alkaliphiles - pH >9; Na+ motive force (not H+)
  18. Internal pH of Acidophiles and Alkaliphiles
    Still ~neutral with some variation (4.6-9.5)
  19. Types of salt loving bacteria
    Halotolerant (0%-5% NaCl), halophile (5%-7% NaCl), extreme halophile (>15% NaCl)
  20. Mechanism of resisting high salt concentration
    Compatible solutes
  21. Oxygen tolerant bacteria types
    Aerobes, facultative organisms (take it or leave it), microaerophiles (only small amounts), aerotolerant (live with it, but don't use it)
  22. Sterillization
    Killing or removal of all viable organisms
  23. Inhibition (cleaning)
    Limiting microbial growth
  24. Deconatimination
    Treatment of an object to make it safe to handle
  25. Disinfection
    Removes all pathogens, but not necessarily all microorganisms
  26. Pasteurization
    Controlled heat to reduce microbial load in heat-sensitive liquids
  27. Bacteriostatic, bacteriocidal, bacteriolytic
    • -static; Inhibits growth only
    • -cidal; Kills only viable cells
    • -lytic; Kills eveything
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Ant
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Bio 3400 - Lecture 5
Updated:
2016-02-01 02:13:08
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Bio 3400
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