Chapter 11 The Prokaryotes

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Chapter 11The Prokaryotes
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Prokaryotic Taxonomy

• Prokaryotic genealogical tree
• Based on 16S ribosomal RNA
• Two domains
• Archaea
• Two phyla
• Bacteria
• 23 phyla

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Figure 11.1
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Domain Archaea

• A1 Crenarchaeota
• One class
• Morphologically diverse
• Metabolically diverse
• A2 Euryarchaeota
• Five classes
• Methanogens
• Extreme halophiles
• Thermoacidophiles

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Domain Bacteria

• B4 Deinococcus-Thermus
• Deinococcus radiodurans
• Resistance to radiation
• Thermus aquaticus
• Production of Taq polymerase
• B5 Chrysiogenetes
• Single species
• Anaerobic respiration using arsenate

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Domain Bacteria

• B10 Cyanobacteria
• Oxygenic photosynthetic bacteria
• Once called blue-green algae (not algae)
• Major nitrogen fixer
• Carbon from CO2
• Nitrogen as N2
• Heterocysts
• Specialized cells for fixation of nitrogen
• Photosynthesis in other cells

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Domain Bacteria

• B11 Chlorobi
• Anoxygenic phototrophic bacteria
• Anaerobic environments
• Photosynthetic
• Found in deep, clear bodies of water
• B12 Proteobacteria
• Largest phylum
• 1300 species
• Alphaproteobacteria class
• Betaproteobacteria class
• Gammaproteobacteria class
• Deltaproteobacteria class
• Epsilonproteobacteria class

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Alphaproteobacteria

• Environmentally important genera
• Acetobacter
• Production of acetic acid in vinegar
• Agrobacterium
• Produce cancerlike disease of plants
• Ti plasmids
• Rhizobium and Bradyrhizobium
• Symbiotic nitrogen-fixing bacteria
• Root nodules of legumes
• Appendaged bacteria
• Prosthecate bacteriafound in aquatic environs

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Betaproteobacteria

• Bordetella
• B. pertussiscauses whooping cough
• Neisseria
• N. meningitidismeningitis
• N. gonorrhoeaeagonorrhea
• Sheathed bacteria
• Tube surrounding bacteria
• Contaminated water and sewage treatment

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Gammaproteobacteria

• 13 orders
• Enterobactgeriales
• Contain the enteric bacteria
• Include human pathogens
• Salmonella typhi
• Shigella spp.
• Yersinia pestis
• Escherichia coli
• Vibrionales
• Curved rods
• Vibrio chlerae--cholera
• Pasteurellales
• Pasteurella and Haemophilus genera
• Pseudomonales
• P. aeruginosa

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Deltaproteobacteria

• Sulfur-reducing bacteria
• Sulfates and sulfur to hydrogen sulfide
• Mud flats, brackish water
• Desulfovibrio spp.
• Black metal sulfides of Black Sea
• Gliding Fruiting bacteria
• Myxobacteria
• Soil organisms

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Epsilonproteobacteria

• Campylobacter
• C. jejunidiarrheal illness
• Helicobacter
• H. pylorigastric ulcers

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Domain Bacteria

• B13 Firmicutes
• Three classes
• Clostridia
• Endospore forming
• Strict anaerobes
• Bacilli
• Endospore forming
• Aerobic and/or facultative anaerobes
• Mollicutes
• Lack cell wall
• Mycoplasmas
• Gram-positive cocci
• Spread between Clostridia and Bacilli classes

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Domain Bacteria

• B13 Firmicutes (continued)
• Gram-positive cocci
• Arrangement important for identification
• Physiological differences
• Staphylococcus
• Facultative anaerobes
• Four genera produce lactic acid
• Streptococcus spp.
• Leuconostoc
• Pediococcus
• Lactobacillus

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Domain Bacteria

• Actinobacteria
• Oddly shaped bacteria
• Arthrobacter genus
• Change shape during growth
• Bifidobacterium genus
• Irregular branched cells
• Propionibacterium acne
• Corynebacterium diptheriae
• Acid-fast
• Mycobacterium
• Tuberculosis and Hansens disease
• Nocardia
• Spore-forming
• Actinomycetes
• Abundant in soil

Figure 11.19
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Domain Bacteria

• B16 Chlamydiae
• Obligate intracellular parasites
• Complicated reproductive cycle
• Reticulate body
• vegetative cell
• multiplication
• Elementary body
• Chlamydiospore
• Spread of infection

Figure 11.21
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Domain Bacteria

• B17 Spirochaetes
• Helical shape
• Corkscrew motility
• Flagellatwo axial filaments
• Metabolically diverse
• Causes of human disease
• Treponema pallidumsyphilus
• Leptospira interrogansleptospirosis
• Borrelia burgdorferiLymes disease

Figure 11.22
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Domain Bacteria

• B20 Bacteroidetes
• Purple nonsulfur bacteria
• Photosynthetic
• Bacteroides
• Mouth and intestinal tract
• B21 Fusobacteria
• Oral and respiratory systems
• F. periodonticum
• dental abscesses
• F. nucleatum
• Respiratory system