Microbiology Module 10.2

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Microbiology Module 10.2
2010-11-01 01:34:38
Microbiology Test

Module 10.2
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  1. Selected Archaea Prokaryotes
    • 2 main phyla
    • Crenarchaeota:Mesophilic members. main archael species. Many thermophiles and hyperthermophiles
    • Euryarchaeota: Diverse group containing methanogens, extreme halophiles, and sulfur metabolizers
  2. Metabolism: Methanogenesis in Euryarchaeota
    • Always anaerobic
    • substrate usually H2 gas, CO2, or formate
    • ATP production via PMF
    • Found in marine sediments, swamps, protozoa, rumens of cows
    • 1 cow can produce 200-400 liters of CH4/day
    • 20-30X more potent at causing global warming
  3. Halobacteria
    • Absolutely dependent on hight salt (3-4M)
    • H. Salinarium has purple membrane composed of..
    • bacteriorhodopsin: light driven proton pump
    • halorhodopsin: light driven transporter. light directly activates the transport of thing into the cell
    • 2 sensory rhodopsins: control movements of cells in response to red and blue light
  4. Bacteria
    • 24 phyla. 22 Gram (-). 2 Gram (+)
    • Classification according to SSU (16S rRNA)
    • Gram (+) characterized according to GC content, metabolism, habitat
  5. Phylum Deinococcus Thermus
    • D. radiodurans resistant to extreme desiccation and high levels of radiation (both produce DS-DNA break)
    • Have OM but gram + via gram stain.
    • Have ornithine replacing lysine in peptidyl -links
    • lack teichoic acid like a normal Gram (-)
    • Nucleoids from tetrads fuse to provide template for fixing DS-DNA breaks
    • Natural habitat unknown
  6. Phyla of photosynthetic of bacteria
    • 4 of the phyla are gram (-): chloroB, Chloroplexi, protobacteria, cyanobacteria
    • Classified according to chl, accessory pigments (green or purple), and reductants used
    • Gram (+) are heliobacteria and all part of very large phylum firmicutes
  7. Photosynthetic pigments
    • Photosynthesis passed around horizontally
    • Non-oxygenic phyla can use sulfur or organic molecules to provide reducing power to make NADPH
    • Have different pigments that absorb light at diff. wavelengths
  8. Phylum Cyanobacteria
    • Very old life forms. Responsible for O2 levels in air
    • Ancestors eventually became chloroplasts
    • Contain Chl-A, some (prochlorophytes) also contain Chl-B
  9. Special Differentiated Cell Structures in anabaena
    • 1. Akinetes: Thick-walled dormant cells that survive desiccation
    • 2. Heterocysts: Differentiate when N sources are limited
    • 3. Heterocysts have thick walls (No O2 production), PSI only and fix N2 for use by neighboring cells
    • N-fixing done in anaerobic environment
  10. Phylum Chlamidia (Gram - Pathogen)
    • No cell wall. obligatory intracellular parasites (.2-1Um)
    • 2 different forms
    • EB form function in extracellular survival. Metabolically inactive.
    • RB Form divide but are not infective
    • C.trachomatis greatest cause of blindness in world
  11. Phylum Spirochaetes (genus Borrelia)
    • Cause Lyme disease:
    • 1st stage: flu-like symptoms. ring rash
    • 2nd stage: involve multi-organ inflammation
    • 3rd stage: Alzheimer's/MS type illness
    • Deer and field mice natural hosts. Transferred thru tick bites
  12. Agrobacterium Tumefaciens
    • Contains Special TI (tumor inducing) that can be used to genetically engineer plants
    • Application: Genes confer herbicide resistance, Bt crops resistant to insects, ethylene resistance confers delay ripening
  13. Caulobacter Crescentus
    • 1 form divides to give rise to the other form
    • model system for dimorphism (unequal binary fisison)
    • model for co-ordination of developmental events thru phosphorelay systems
  14. Bdellovibrio bacteriovorus
    • 1 of the few predatory bacteria (preys on Gram (-) E.coli)
    • Bores into periplasmic space and reproduces
    • Interrupts CM and feasts on cytoplasm
  15. Myxococcus Xanthus
    • Predatory
    • Vegetative cells secretory layers secrete slime
    • Move in swarms, consuming other microbes
    • when prey become scarce, cells pile up and form fruiting bodies, releasing mxyspores
    • Cell-Cell communications mediated by 5 signals
  16. HJigh GC Gram Positive Bacteria
    • Phylum= Actinobacteria
    • Include TB, diphtheria, acne
    • Other members make cmpds that are at the foundation of antibiotic and chemotherapy development
    • May act a lot like small fungi
  17. Phylum firmicutes, Class Bacilli
    • Low GC
    • Includes important pathogens: Streptococcus, staphylococcus, and bacillus
    • All endospore formers in this phylum
    • Also all photosynthetic Gram (+) microbes
  18. Fermented Milks
    • over 400 diff. fermented milk products
    • LAB (lactic acid bacteria) strictly fermentative, aero-, and acid tolerant
    • Cheese can be produced when acid production leads to curdled proteins