The Prokaryotes Domains Bacteria and Archaea (PowerPoint) by nikeborome

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									     The Prokaryotes:
Domains Bacteria and Archaea

•One circular chromosome
  –not in a membrane
•No histones
•No organelles
•Peptidoglycan cell walls (bacteria)
•Pseudomuerin cell walls (archaea)
•Binary fission
              Domain Bacteria
• Proteobacteria
  – Largest taxonomic group of bacteria
  – Mythical Greek god, Proteus, who could
    assume many shapes
  – Subgroups are designated by Greek letters
  – Includes most of the gram-negative bacteria
  – Phylogeny based on rRNA studies
  – Common photosynthetic ancestor
    • few are still photosynthetic
              The  (alpha) Proteobacteria




•Some grow at low
nutrient levels
•Some have unusual
morphology
    •prosthecae
•Many are agriculturally
important
    •nitrogen fixers
             The  (alpha) Proteobacteria
• Human pathogens:
  – Bartonella - Gram- bacillus
     • Cat-scratch disease
  – Brucella – non-motile coccobacilli
     • Brucellosis
• Obligate intracellular parasites:
  – Rickettsia – Gram – bacillus or coccobacilli
     •   Arthropod-borne cause spotted fevers
     •   R. prowazekii - Epidemic typhus (lice)
     •   R. typhi - Endemic murine typhus (fleas)
     •   R. rickettsii - Rocky Mountain Spotted Fever (ticks)
The  (alpha) Proteobacteria
         The  (alpha) Proteobacteria
• Have prosthecae:
  – Caulobacter
    • Stalked bacteria found in
      low nutrient aquatic
      environment
    • Stalks increase surface
      area for nutrient uptake

  – Hyphomicrobium
    • Budding bacteria found in
      low nutrient environment
           The  (alpha) Proteobacteria
• Nitrogen-fixing
  bacteria:
   – Azospirillum
     • Grows in close
       association with the
       roots of tropical grasses
       and sugar cane
     • Fix nitrogen for plant
  – Rhizobium
     • Fix nitrogen in the roots
       of plants
     • Infect roots of legumes
       forming root nodules
         The  (alpha) Proteobacteria



• Plant pathogen:
  – Agrobacterium
     • Inserts a
       plasmid into
       plant cells,
       inducing a
       tumor
     • Crown gall
          The  (alpha) Proteobacteria

• Produce acetic acid from ethyl alcohol:
  – Acetobacter
  – Gluconobacter
  – Important commercially
• Nitrifying bacteria :
  – Oxidize nitrogen for energy
  – Fix CO2 for carbon source
     • Nitrobacter. NH4+  NO2– (ammonium to nitrite)
     • Nitrosomonas. NO2–  NO3– (nitrite to nitrate)
     • Agriculturally important
         The  (alpha) Proteobacteria


• Wolbachia
  – Most common
    infectious bacteria
  – Live as endosymbionts
    in insects and other
    animals
  – Greatly influence
    survival and
    reproduction of host
  – Infected male + not
    infected female = no
    offspring
           The  (beta) Proteobacteria




•Often use nutrients that
diffuse away from areas of
anaerobic decomposition of
organic matter
•Can utilize hydrogen gas,
ammonia, and methane for
energy
•Several medically important
pathogens are in this group
            The  (beta) Proteobacteria

• Thiobacillus
   – Chemoautotrophic, oxidize sulfur: H2S  SO42–
• Zoogloea
   – Slimy masses in aerobic sewage-treatment processes


• Sphaerotilus-
   - Chemoheterotophic,
   - form hollow filamentous
     sheaths
   - common in sewage
              The  (beta) Proteobacteria
• Spirillum
  – Chemoheterotrophic
  – Helical with polar flagella
  – Large, areobic


• Neisseria
  – Chemoheterotrophic, cocci,
    aerobic
  – N. meningitidis
     • meningitis
  – N. gonorrhoeae
     • Gonorrhoea
              The  (beta) Proteobacteria

• Bordetella
  – Chemoheterotrophic, aerobic, rods
  – B. pertussis - whooping cough


• Burkholderia
  –   Previously grouped with Pseudomonas
  –   Nosocomial infections
  –   Grow in disinfectant solutions
  –   Metabolize respiratory secretions in cystic fibrosis
      patients
            The  (gamma) Proteobacteria




•Largest subgroup of the proteobacteria
•Great variety of physiological types
•Includes the enterics
    •facultative anaerobic, G- rods that
    inhabit intestinal tract of animals
       The  (gamma) Proteobacteria


• Beggiatoa
  – Chemoautotrophic, oxidize H2S to S0 for
    energy
  – Beggiatoa alba
• Francisella
  – Chemoheterotrophic
  – Francisella tularensis - tularemia
           The  (gamma) Proteobacteria

• Pseudomonadales:
  – Pseudomonas
     • Opportunistic
       pathogens
         – Nosocomial infections
     • Polar flagella
     • Extra-cellular pigments
  – Azotobacter and Azomonas
     • Nitrogen fixing, soil bacteria
  – Moraxella
     • Moraxella lucunata
     • Conjunctivitis
          The  (gamma) Proteobacteria
• Legionellales:
   – Legionella
      • Found in streams,
        warm-water pipes,
        cooling towers
      • L. pneumophilia
          – Causes a form of
            pneumonia called
            legionellosis
   – Coxiella
      • Coxiella burnetii
      • Q fever transmitted via
        aerosols or milk
      • Obligate intracellular
        pathogen
         The  (gamma) Proteobacteria


• Vibrionales:
  – Facultative anaerobe
  – curved rod or comma shape
  – Found in coastal water
     • Vibrio cholerae causes
       cholera
     • V. parahaemolyticus
       causes gastroenteritis
         The  (gamma) Proteobacteria

• Enterobacteriales (enterics):
     • Peritrichous flagella, facultatively anaerobic, rods
     • Inhabit intestinal tract of animals (humans)
         – Escherichia
         – Salmonella
         – Shigella
         – Klebsiella
         – Serratia
         – Proteus
         – Yersinia
         – Erwinia
         – Enterobacter
• Escherichia
  – Coliforms – fecal contamination
  – UTI and Travelers Diarrhea
  – Food posioning – E. coli 0157:H7
• Salmonella
  – Salmonella enterica
  – Salmonella enterica servor typhi – typhoid fever
• Shigella
  – Shigellosis (bacillary dysentery)
• Klebsiella
  – Klebsiella pneumoniae
  – pneumonia
• Serratia
  – Serratia marcescens
  – Red pigments
• Proteus
  – Swarmer cells
  – UTI and wound infections
• Yersinia
  – Yersinia pestis - plague
• Enterobacter
  – Enterobacter aerogenes and cloacae
  – UTI and nosocomial infections
• Erwinia
  – Plant pathogen
           The  (gamma) Proteobacteria

• Pasteurellales:
  – Pasteurella
     •   Cause pneumonia and septicemia
     •   mainly pathogens of domestic animals
     •   can be passed to humans from cat and dog bites
     •   Pasteurella multocidia
  – Haemophilus
     • may inhabit mucous membranes of upper respiratory tract,
       mouth, vagina, and intestinal tract
     • require blood (heme – X factor) and the cofactor NAD (V factor)
     • H. ducreyi
     • H. influenzae does not cause the flu
         – meningitis, pneumonia, bronchitis, septic arthritis, frequent
            cause of earaches in children
           The  (delta) Proteobacteria

•Some species are predators on other bacteria
•Important contributors to the sulfur cycle
           The  (delta) Proteobacteria

• Bdellovibrio
  – Prey on other bacteria
  – attack other gram (-) bacteria similar to the way a virus
    would
• Desulfovibrionales
  – obligate anaerobe
  – Use S instead of O2 as final electron acceptor
• Myxococcales
  – Move by gliding, leave a slime trail
  – Cells aggregate to form myxospores
  – Most complex life cycle of all bacteria
The  (delta) Proteobacteria
The  (delta) Proteobacteria
       The  (epsilon) Proteobacteria
•Slender gram (-) rods that are helical or vibrioid
    •helical without a complete turn
•Motile by means of flagella
•Microaerophilic
       The  (epsilon) Proteobacteria
– Campylobacter – microaerophilic
  vibrio
   • C. fetus can cause spontaneous
     abortion in domestic animals
   • C. jejuni is a leading cause of
     outbreaks of food borne disease
     mainly transmitted by undercooked
     poultry


– Helicobacter – microaerophilic
  vibrio
   • H. pylori is the most common cause
     of stomach ulcers in humans

								
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