Microbiology - 0328 - PILI, FIMBRIAE AND FLAGELLA

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  1. PILI vs FIMBRIAE

    • Fimbriae latin for thread or fiber, shorter and dense, coded on chomosome.
    • Pili latin for hair or hairlike, longer and fewer. coded on plasmid (F plasmid, esp. conjugated or sex pili)
  2. Fimbriae Functions
    • promotes attachment to other bacteria or host.
    • Biofilm formation
    • important virulence factor for colonization and infection.
    • Some tips of fimbria may contain lectines (sugar binding protein)
  3. Pili consist of the protein _____.
    Pilin
  4. Pili Functions
    • cell surface associations.
    • Enable attaching to epithelial cells or bacteria. aggregation; build up biofilms and plaques.
    • twitching movement by type IV pili, establish new microcolony
    • Conjugate/sex pili (type IV; conjugation & transformation; important for developing drug resistance;virus adherence)
  5. Attachment control
    saturate the system w/ oligosacchride, block the bacteria before the pili's receptor binds to host cell surface sugars.
  6. Microbial mobility
    • Twitching: semi-solid surface; 1.5% agar; type IV pili
    • Swimming: flagella; liquid enviroment; 0.3% agar
    • Swarming: flagella and the secretion of polysaccharide slim; semisolid surfaces; 0.5% agar.
    • Gliding motility: secretion of slim compound in bacteria which lack pili and flagella; semisolid surfaces.
  7. Flagellum consist of the protein _____. Involve in ______ motility.
    • flagellin
    • swimming and swarming
  8. Flagellum structure
    • basal body:
    • rod
    • C ring (cytoplasmic)
    • Mot: stator, using [H] gradient energy
    • Fli: motor switch
    • MS ring - inner membrane
    • C + MS = rotor
    • P ring - periplasmic; attached to peptidoglycan
    • L ring - attached to LPS (not seen in G+)
    • hook
    • filament
  9. Flagellum Function
    • Involved in cell movement in liquid environments.
    • Has a role in reaching the surface.
    • Has a role in attaching to the surface.
    • Could have a role in surface motility.
    • Could have a role in biofilm detachment.
  10. Microbial Taxes
    • The movement towards or away from an agent
    • Chemotaxis
    • phototaxis
    • osmotaxis
    • airotaxis
  11. Bacteria are too small to sense gradient along the length of the cell (spatially) but can sense it temporally by monitoring the environment as it moves.
  12. Methods for Measuring Chemotaxis
    • capillary
    • microscopy
  13. Axial filament
    endoflagella moves the cell by rotating in spirochetes
  14. Spirochetes
    causing Lyme disease, Syphilis, periodontal disease, Trench mouth.
  15. Gene (DNA) vs. Protein (gene product):
    • tadA, tadB, tadC
    • TadA, TadB, TadC
  16. Which pairing of bases are more stable
    • GC > AT
    • archea has more GC
  17. Each base pair is ___. One helical turn is ___ base pairs.
    • 0.34 nm
    • 10
  18. ______ allows the packaging of long (circular) DNA molecule into the cell. The process is catalyzed by ______. ____ helps stabilizing _____. Each cell contains ____ copies of each gene: _____.
    • Supercoiling
    • nick, rotate around helix, and seal.
    • Topoisomerases - DNA Gyrase (prokaryotic)
    • protein
    • supercoiled domains
    • one
    • haploid (eukaryon has two copies: diploid)
  19. Supercoiled DNA is located at ________, not ____.
    • nucleoid
    • nucleus
  20. endosymbiosis
    mitochondria and chloroplasts contain their own genomes and are highly derived from ancestors of Bacteria. Mitochondria and chloroplasts were thus once free-living cells that entered Eukarya eons ago
  21. Correlation between size of bacterium and life styles
    Symbiont < Parasites < Free living bacteria
  22. Transposons
    • Segments of DNA that can move from one region of DNA to another.
    • Role in genetic variation. the force that drives evolution
  23. Plasmid
    • circular extrachromosomal genetic elements.
    • Small- about 3000bp.
    • Multiple copies in the cell-copy number (1-100 per/cell)
    • do not duplicate at the same time with chromosome
    • wide range: both G+ and G-
    • narrow range: only some
    • Can be obtained and lost
  24. Plasmid functions
    • Contains no essential function but may provide a selective growth advantage under certain conditions. such as:
    • Antibiotic resistance- R plasmids.
    • Enzymes for degradation of organic compounds.
    • Virulence factors- toxins.
    • Antibiotics- Bacteriocins.
    • Conjugative plasmid-Carries genes for sex pili and transfer of the plasmid
  25. RNA polymerase and _____ are involved in the initiation of transcription by ______.
    • sigma factor
    • promoter and initiation site
    • sigma is released once transcription starts
  26. Transcriptome
    • a collection of all the transcripts present in a given cell (rRNA, tRNA, mRNA).
    • analyzing transcriptome in a cell - determine when each gene is turned on or off.
  27. Complementary DNA cDNA
    DNA synthesized from mRNA using reverse transcriptase (RNA-dependent DNA polymerase).
  28. southern northern western
    • DNA
    • RNA
    • proteins
  29. ribosome constituents
    • 30S subunit contains 16S rRNA and 21 proteins
    • 50S subunit contains 5S rRNA, 23S rRNA and 31 proteins.
    • Shine-Dalgarno- a seq on the mRNA that is complimentary to base seq of the 16S and holds the ribosome to the mRNA. located 8 base-pairs upstream of the start codon.
  30. Transformation
    • The uptake of free DNA by a bacterial cell
    • involves the induction (chemically or electrically) of competence - a state in which cells are able to take up free DNA. not all cells are naturally transformable.
    • • DNA binding.
    • • DNA uptake.
    • • Stable maintenance of the acquired DNA either by
    • recombination or by DNA maintenance.
  31. Transduction
    • DNA transferred from one bacterium to another by a virus (bacteriophage).
    • Transduction happens through either the lytic cycle or the lysogenic cycle (integrated DNA stays dormant).
  32. Conjugation
    • Transfer of genetic material (plasmid or transposon) between (from a donor to a recipient) bacteria through direct cell-to-cell contact.
    • - Plasmid DNA
    • - Chromosome DNA
  33. The genetic information transferred is often beneficial to the recipient cell:
    • antibiotic resistance: R factor
    • ability to utilize new metabolites: Dissimilation plasmids
    • Conjugative (F) plasmid, genes for sex pili
    • Nothing essential
  34. how to know if integration occurred?
    island of different GC content, may come from plasmids, viruses, other sources
  35. Gene cloning
    • foreign gene and vector both w/ sticky ends, treated by restriction enzyme
    • recombinate w/ the help of DNA ligase
    • introduction of recombinant vector into host
  36. Bacteria
    • •  Prokaryotes
    • •  Peptidoglycan cell walls
    • •  Binary fission
    • •  For energy, use organic chemicals, inorganic chemicals, or photosynthesis
  37. Archaea
    • •  Prokaryotic
    • •  Lack peptidoglycan
    • •  Live in extreme environments
    • •  Include:
    • – Methanogens
    • – Extreme halophiles
    • – Extreme thermophiles
  38. Fungi
    • •  Eukaryotes
    • •  Chitin cell walls
    • •  Use organic chemicals for energy
    • •  Yeasts are unicellular
    • •  Molds and mushrooms are multicellular consisting of masses of mycelia, which are composed of filaments called hyphae
  39. Protozoa
    • •  Eukaryotes
    • •  Absorb or ingest organic chemicals
    • •  May be mobile
  40. Algae
    • •  Eukaryotes
    • •  Cellulose cell walls
    • •  Use photosynthesis for energy
    • •  Produce molecular oxygen and organic compounds
  41. Diagnostic Microbiology
    • Growth-Dependent Diagnostic Methods
    • - Culture Organisms
    • - Isolate Pure Cultures
    • - Microscopy and differential staining.
    • - Study Metabolism of Cultures
    • - Differential growth conditions and media; Antimicrobial Drug Susceptibility
    • - phage typing
    • - fatty acid analysis
    • Growth-Independent Diagnostic Methods
    • immunology
    • - antibody
    • - Agglutination
    • - fluorescent antibody (direct)
    • - Enzyme-Linked Immunosorbent Assay (ELISA): show change in color; specificity depends on the specificity of the antibody
    • Molecular
    • - PCR
    • - Southern/Northern blot
    • - FISH
    • - rRNA: large database

Card Set Information

Author:
akhan
ID:
319054
Filename:
Microbiology - 0328 - PILI, FIMBRIAE AND FLAGELLA
Updated:
2016-04-18 07:04:41
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microbiology
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microbiology
Description:
Microbiology - 0328 - PILI, FIMBRIAE AND FLAGELLA
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