MICROBIOLOGY
Chapter 11
The Prokaryotes:
Domains Bacteria and Archaea
Dr. Abdelraouf A. Elmanama
Ph. D Microbiology
Medical Technology Department, Faculty of Science, Islamic University-Gaza
2008
The Prokaryotes:
Domains Bacteria and Archaea
• One circular chromosome, not in a membrane
• No histones
• No organelles
• Peptidoglycan cell walls
• Binary fission
2008
Domain Bacteria
• Proteobacteria
• Mythical
Greek god,
Proteus, who
could
assume
many shapes
• Gramnegative
2008
The  (alpha) Proteobacteria
• Human pathogens:
• Bartonella
• B. hensela
Cat-scratch disease
• Brucella
Brucellosis
2008
The  (alpha) Proteobacteria
• Obligate intracellular parasites:
• Ehrlichia. Tick-borne, ehrlichiosis
• Rickettsia. Arthropod-borne, spotted fevers
2008
• R. prowazekii
Epidemic typhus
• R. typhi
Endemic murine typhus
• R. rickettsii
Rocky Mountain Spotted Fever
The  (alpha) Proteobacteria
2008
Figure 11.1
The  (alpha) Proteobacteria
• Wolbachia. Live
in insects and
other animals
2008
The  (alpha) Proteobacteria
• Have prosthecae:
• Caulobacter. Stalked
bacteria found in lakes
• Hyphomicrobium.
Budding bacteria found
in lakes
2008
Figure 11.2 & 3
The  (alpha) Proteobacteria
• Plant pathogen:
• Agrobacterium.
Insert a plasmid
into plant cells,
inducing a
tumor
2008
Figure 9.17
The  (alpha) Proteobacteria
• Chemoautotrophic:
• Oxidize nitrogen for energy
• Fix CO2
• Nitrobacter. NH3+  NO2–
• Nitrosomonas. NO2–  NO3–
2008
The  (alpha) Proteobacteria
• Nitrogen-fixing
bacteria:
• Azospirillum
• Grow in soil,
using nutrients
excreted by
plants
• Fix nitrogen
• Rhizobium
• Fix nitrogen in the
roots of plants
2008
Figure 27.5
The  (alpha) Proteobacteria
• Produce acetic acid from ethyl alcohol:
• Acetobacter
• Gluconobacter
2008
The  (beta) Proteobacteria
2008
The  (beta) Proteobacteria
• Thiobacillus
• Chemoautotrophic, oxidize sulfur: H2S  SO42–
• Sphaerotilus
• Chemoheterotophic, form sheaths
2008
Figure 11.5
The  (beta) Proteobacteria
• Neisseria
• Chemoheterotrophic,
cocci
• N. meningitidis
• N. gonorrhoeae
• Spirillum
• Chemoheterotrophic,
helical
2008
Figure 11.4 & 6
The  (beta) Proteobacteria
• Bordetella
• Chemoheterotrophic, rods
• B. pertussis
• Burkholderia. Nosocomial infections
• Zoogloea. Slimy masses in aerobic sewage-treatment
processes
2008
The  (gamma) Proteobacteria
2008
The  (gamma) Proteobacteria
• Pseudomonadales:
• Pseudomonas
• Opportunistic
pathogens
• Metabolically
diverse
• Polar flagella
2008
• Azotobacter and Azomonas.
Nitrogen fixing
• Moraxella.
Conjunctivitis
Figure 11.7
The  (gamma) Proteobacteria
• Legionellales:
• Legionella
• Found in streams,
warm-water pipes,
cooling towers
• L. pneumophilia
• Coxiella
• Q fever
transmitted via
aerosols or milk
2008
Figure 24.15b
The  (gamma) Proteobacteria
• Vibrionales:
• Found in coastal water
• Vibrio cholerae
causes cholera
• V. parahaemolyticus
causes gastroenteritis
2008
Figure 11.8
The  (gamma) Proteobacteria
• The  (gamma) Proteobacteria
• Enterobacteriales (enterics):
• Peritrichous flagella, facultatively anaerobic
• Enterobacter
• Erwinia
• Escherichia
• Klebsiella
• Proteus
• Salmonella
• Serratia
• Shigella
• Yersinia
2008
The  (gamma) Proteobacteria
2008
Figure 11.9a, b
The  (gamma) Proteobacteria
• Pasteurellales:
• Pasteurella
• Cause pneumonia and septicemia
• Haemophilus
• Require X (heme) and V (NAD+, NADP+) factors
2008
The  (gamma) Proteobacteria
• Beggiatoa
• Chemoautotrophic, oxidize H2S to S0 for energy
• Francisella
• Chemoheterotrophic, tularemia
2008
The  (delta) Proteobacteria
2008
The  (delta) Proteobacteria
• Bdellovibrio. Prey on other bacteria
• Desulfovibrionales. Use S instead of O2 as final
electron acceptor
• Myxococcales. Gliding. Cells aggregate to form
myxospores
2008
The  (delta) Proteobacteria
2008
Figure 11.10a
The  (delta) Proteobacteria
2008
Figure 11.1b
The  (epsilon) Proteobacteria
2008
The  (epsilon) Proteobacteria
• Campylobacter
• One polar flagellum
• Gastroenteritis
2008
Figure 11.1a
The  (epsilon) Proteobacteria
• Helicobacter
• Multiple flagella
• Peptic ulcers
• Stomach cancer
2008
Figure 11.1b
The Nonproteobacteria Gram-Negative Bacteria
2008
Cyanobacteria
• Oxygenic photosynthesis
• Gliding motility
• Fix nitrogen
2008
Cyanobacteria
2008
Figure 11.12a-c
Purple and Green Photosynthetic Bacteria
• Anoxygenic photosynthesis
• Purple and green sulfur bacteria
2H2O + CO2
2H2S + CO2
2008
light
light
(CH2O) + H2O + O2
(CH2O) + H2O + 2S0
Chlamydiae
• C. trachomatis
• Trachoma
• STD, urethritis
• C. pneumoniae
• C. psittaci
• Causes psittacosis
2008
In Bergey's Manual, Volume 5
2008
Figure 11.22a
In Bergey's Manual, Volume 5
2008
Figure 11.22b
Spirochaetes
• Borrelia
• Leptospira
• Treponema
2008
Figure 11.23
Bacteroidetes
• Anaerobic
• Bacteroides. In mouth and large intestine
• Cytophaga. Cellulose-degrading in soil
2008
Fusobacteria
• Fusobacterium
• Found in mouth
• May be involved in
dental diseases
2008
Figure 11.24
Firmicutes
• Low G + C
• Gram-positive
2008
Clostridiales
• Clostridium
• Endosporeproducing
• Obligate anaerobes
• Epulopiscium
2008
Figure 11.14 & 15
Bacillales
• Bacillus
• Endospore-producing
rods
2008
Figure 11.16b
Bacillales
• Staphylococcus
• Cocci
2008
Figure 1.17