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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
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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
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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
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Bacteria
- 24 phyla. 22 Gram (-). 2 Gram (+)
- Classification according to SSU (16S rRNA)
- Gram (+) characterized according to GC content, metabolism, habitat
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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Phylum firmicutes, Class Bacilli
- Low GC
- Includes important pathogens: Streptococcus, staphylococcus, and bacillus
- All endospore formers in this phylum
- Also all photosynthetic Gram (+) microbes
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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
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