Download Sulfur-oxidizing bacteria

LECTURE PRESENTATIONS
For BROCK BIOLOGY OF MICROORGANISMS, THIRTEENTH EDITION
Michael T. Madigan, John M. Martinko, David A. Stahl, David P. Clark
Chapter 17
Lectures by
John Zamora
Middle Tennessee State University
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Bacteria: The
Proteobacteria
I. The Phylogeny of Bacteria
• 17.1 Phylogenetic Overview of Bacteria
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Figure 17.1
Deferribacter
Cytophaga
Flavobacteria
Spirochetes
Planctomyces/
Pirellula
Verrucomicrobiaceae
Green sulfur
bacteria
Deinococci
Green nonsulfur
bacteria
Chlamydia
Cyanobacteria
Thermotoga
Actinobacteria
Firmicutes and Mollicutes
Gram-positive
bacteria
Thermodesulfobacterium
Nitrospira

Aquifex





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See Figure 17.2
Proteobacteria
17.1 Phylogenetic Overview of Bacteria
• Proteobacteria (Figure 17.2)
– A major lineage (phyla) of Bacteria
– Includes many of the most commonly
encountered bacteria
– Most metabolically diverse of all Bacteria
• Chemolithotrophy, chemoorganotrophy,
phototrophy
– Morphologically diverse
– Divided into five classes
• Alpha-, Beta-, Delta-, Gamma-, Epsilon-
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Figure 17.2
16S rRNA Gene Tree of Proteobacteria Proteobacterial
Classes
Bacillus
Nitrosococcus
Thermochromatium
Acidithiobacillus
Beggiatoa
Gamma
Pseudomonas
Vibrio
Escherichia
Methylobacter
Gallionella
Nitrosomonas
Methylophilus
Derxia
Beta
Ralstonia
Spirillum
Rhodocyclus
Thiobacillus
Neisseria
Methylobacterium
Nitrobacter
Rhodopseudomonas
Beijerinckia
Alpha
Paracoccus
Azotobacter
Rickettsia
Acetobacter
Zeta
Mariprofundus
Campylobacter
Sulfurimonas
Epsilon
Thiovulum
Wolinella
Desulfosarcina
Desulfovibrio
Delta
Myxococcus
Nitrospina
Major metabolisms
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Chemolithotrophy
Anoxygenic phototrophy
Methylotrophy
Sulfur compounds (H2S, S0, etc.)
Ferrous iron (Fe2)
Sulfate reduction
Nitrogen fixation
Ammonia (NH3) or nitrite (NO2)
Hydrogen (H2)
II. Phototrophic, Chemolithotrophic, and
Methanotrophic Proteobacteria
•
•
•
•
•
17.2 Purple Phototrophic Bacteria
17.3 The Nitrifying Bacteria
17.4 Sulfur- and Iron-Oxidizing Bacteria
17.5 Hydrogen-Oxidizing Bacteria
17.6 Methanotrophs and Methylotrophs
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17.2 Purple Phototrophic Bacteria
• Purple phototrophic bacteria
– Carry out anoxygenic photosynthesis; no O2
evolved
– Morphologically diverse group
– Genera fall within the Alpha-, Beta-, or
Gammaproteobacteria
– Contain bacteriochlorophylls and carotenoid
pigments (Figure 17.3)
– Produce intracytoplasmic photosynthetic
membranes with varying morphologies
(Figure 17.4)
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Figure 17.3
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Figure 17.4
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17.2 Purple Phototrophic Bacteria
• Purple sulfur bacteria (Figure 17.5)
– Use hydrogen sulfide (H2S) as an electron
donor for CO2 reduction in photosynthesis
– Sulfide oxidized to elemental sulfur (S0) that is
stored as globules either inside or outside
cells
• Sulfur later disappears as it is oxidized to
sulfate (SO42)
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Figure 17.5
© 2012 Pearson Education, Inc.
17.2 Purple Phototrophic Bacteria
• Purple sulfur bacteria (cont’d)
– Many can also use other reduced sulfur
compounds, such as thiosulfate (S2O32)
– All are Gammaproteobacteria
– Found in illuminated anoxic zones of lakes and
other aquatic habitats where H2S accumulates,
as well as sulfur springs (Figure 17.6)
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Figure 17.6
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17.2 Purple Phototrophic Bacteria
• Purple nonsulfur bacteria (Figure 17.7)
– Organisms able to use sulfide as an electron
donor for CO2 reduction
– Most can grow aerobically in the dark as
chemoorganotrophs
– Some can also grow anaerobically in the dark
using fermentation or anaerobic respiration
– Most can grow photoheterotrophically using
light as an energy source and organic
compounds as a carbon source
– All in Alpha- and Betaproteobacteria
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Figure 17.7
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17.3 The Nitrifying Bacteria
• Nitrifying bacteria
– Able to grow chemolithotrophically at the expense
of reduced inorganic nitrogen compounds
– Found in Alpha-, Beta-, Gamma-, and
Deltaproteobacteria
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17.3 The Nitrifying Bacteria
• Nitrifying bacteria (cont’d)
– Nitrification (oxidation of ammonia to nitrate)
occurs as two separate reactions by different
groups of bacteria
• Ammonia oxidizers (nitrosifiers; e.g.,
Nitrosococcus; Figure 17.8a)
• Nitrite oxidizer (e.g., Nitrobacter; Figure 17.8b)
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Figure 17.8
Reaction: NH3  1 12 O2
Reaction: NO2 
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1
2
NO2  H2O
O2
NO3
17.3 The Nitrifying Bacteria
• Nitrifying bacteria (cont’d)
– Many species have internal membrane
systems that house key enzymes in
nitrification
• Ammonia monooxygenase: oxidizes NH3 to
NH2OH
• Nitrite oxidase: oxidizes NO2 to NO3
• Widespread in soil and water
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17.3 The Nitrifying Bacteria
• Nitrifying bacteria (cont’d)
– Highest numbers in habitats with large amounts
of ammonia
• Examples: sites with extensive protein
decomposition and sewage treatment facilities
– Most are obligate chemolithotrophs and aerobes
• One exception is annamox organisms, which
oxidize ammonia anaerobically
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17.4 Sulfur- and Iron-Oxidizing Bacteria
• Sulfur-oxidizing bacteria
– Grow chemolithotrophically on reduced sulfur
compounds
– Two broad classes:
• Neutrophiles
• Acidophiles
– Some acidophiles able to use ferrous iron (Fe2+)
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17.4 Sulfur- and Iron-Oxidizing Bacteria
• Sulfur-oxidizing bacteria (cont’d)
– Thiobacillus and close relatives are most studied
• Rod-shaped
• Sulfur compounds most commonly used as
electron donors are H2S, S0, S2O32; generates
sulfuric acid
– Achromatium
• Common in freshwater sediments
• Spherical cells
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17.4 Sulfur- and Iron-Oxidizing Bacteria
• Sulfur-oxidizing bacteria (cont’d)
– Some obligate chemolithotrophs possess
special structures that house Calvin cycle
enyzmes (carboxysomes; Figure 17.9)
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Figure 17.9
© 2012 Pearson Education, Inc.
17.4 Sulfur- and Iron-Oxidizing Bacteria
• Sulfur-oxidizing bacteria (cont’d)
– Beggiatoa (Figure 17.10)
• Filamentous, gliding bacteria
• Found in habitats rich in H2S
– Examples: sulfur springs, decaying seaweed
beds, mud layers of lakes, sewage-polluted
waters, and hydrothermal vents
• Most grow mixotrophically
– with reduced sulfur compounds as electron
donors
– and organic compounds as carbon sources
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Figure 17.10
© 2012 Pearson Education, Inc.
17.4 Sulfur- and Iron-Oxidizing Bacteria
• Sulfur-oxidizing bacteria (cont’d)
– Thioploca (Figure 17.11)
• Large, filamentous sulfur-oxidizing bacteria that
form cell bundles surrounded by a common
sheath
• Thick mats found on ocean floor off Chile and
Peru
• Couple anoxic oxidation of H2S with reduction of
NO3 to NH4+
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Figure 17.11
© 2012 Pearson Education, Inc.
17.4 Sulfur- and Iron-Oxidizing Bacteria
• Sulfur-oxidizing bacteria (cont’d)
– Thiothrix (Figure 17.12)
• Filamentous sulfur-oxidizing bacteria in which
filaments group together at their ends by a
holdfast to form cellular arrangements called
rosettes
• Obligate aerobic mixotrophs
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Figure 17.12
© 2012 Pearson Education, Inc.
17.5 Hydrogen-Oxidizing Bacteria
• Hydrogen-oxidizing bacteria
– Most can grow autotrophically with H2 as sole
electron donor and O2 as electron acceptor
(“knallgas” reaction)
– Both gram-negative and gram-positive
representatives
– Contain one or more hydrogenase enzymes
that use H2 either to produce ATP or for
reducing power for autotrophic growth
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17.5 Hydrogen-Oxidizing Bacteria
• Hydrogen-oxidizing bacteria (cont’d)
– Most are facultative chemolithotrophs and can
grow chemoorganotrophically (Figure 17.13)
– Some can grow on carbon monoxide (CO) as
electron donor (carboxydotrophs)
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Figure 17.13
© 2012 Pearson Education, Inc.
17.6 Methanotrophs and Methylotrophs
• Methanotrophs
– Use CH4 and a few other one-carbon (C1)
compounds as electron donors and source of
carbon
– Widespread in soil and water
– Obligate aerobes
– Morphologically diverse
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17.6 Methanotrophs and Methylotrophs
• Methylotrophs
– Organisms that can grow using carbon
compounds that lack C-C bonds
– Most are also methanotrophs
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17.6 Methanotrophs and Methylotrophs
• C1 methanotrophs
– Methanotrophs contain methane monooxygenase
• Incorporates an atom of oxygen from O2 into
methane to produce methanol
– Methanotrophs contain large amounts of sterols
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17.6 Methanotrophs and Methylotrophs
• Classification of Methanotrophs
– Two major groups:
• Type I
• Type II
– Contain extensive internal membrane systems
for methane oxidation
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17.6 Methanotrophs and Methylotrophs
• Type I methanotrophs (Figure 17.14)
– Assimilate C1 compounds via the ribulose
monophosphate cycle
– Gammaproteobacteria
– Membranes arranged as bundles of discshaped vesicles
– Lack complete citric acid cycle
– Obligate methylotrophs
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17.6 Methanotrophs and Methylotrophs
• Type II methanotrophs (Figure 17.14)
– Assimilate C1 compounds via the serine pathway
– Alphaproteobacteria
– Paired membranes that run along periphery of
cell
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Figure 17.14
© 2012 Pearson Education, Inc.
17.6 Methanotrophs and Methylotrophs
• Ecology and Isolation of Methanotrophs
– Widespread in aquatic and terrestrial
environments
– Methane monooxygenase also oxidizes ammonia;
competitive interaction between substrates
– Certain marine mussels have symbiotic
relationships with methanotrophs (Figure 17.15)
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Figure 17.15
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III. Aerobic and Facultatively Aerobic
Chemoorganotrophic Proteobacteria
•
•
•
•
•
•
•
17.7 Pseudomonas and the Pseudomonads
17.8 Acetic Acid Bacteria
17.9 Free-Living Aerobic Nitrogen-Fixing Bacteria
17.10 Neisseria, Chromobacterium, and Relatives
17.11 Enteric Bacteria
17.12 Vibrio, Aliivibrio, and Photobacterium
17.13 Rickettsias
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17.7 Pseudomonas and the
Pseudomonads
• All genera within the pseudomonad group are
– Straight or curved rods with polar flagella
– Chemoorganotrophs
– Obligate aerobes
• Species of the genus Pseudomonas and
related genera can be defined on the basis of
phylogeny and physiological characteristics
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Figure 17.16
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17.7 Pseudomonas and the
Pseudomonads
• Pseudomonads
– Nutritionally versatile
– Ecologically important organisms in water and
soil
– Some species are pathogenic
• Includes human opportunistic pathogens and
plant pathogens
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17.7 Pseudomonas and the
Pseudomonads
• Zymomonas
– Genus of large, gram-negative rods that carry
out vigorous fermentation of sugars to ethanol
– Used in production of fermented beverages
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17.8 Acetic Acid Bacteria
• Acetic acid bacteria
– Organisms that carry out complete oxidation
of alcohols and sugars
• Leads to the accumulation of organic acids as
end products
– Motile rods
– Aerobic
– High tolerance to acidic conditions
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17.8 Acetic Acid Bacteria
• Acetic acid bacteria (cont’d)
– Commonly found in alcoholic juices
• Used in production of vinegar
– Some can synthesize cellulose
– Colonies can be identified on CaCO3 agar
plates containing ethanol
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Figure 17.17
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17.9 Free-Living Aerobic Nitrogen-Fixing
Bacteria
• Major genera capable of fixing N2 nonsymbiotically
are Azotobacter, Azospirillum, and Beijerinckia
– Azotobacter are large, obligately aerobic rods
(Figure 17.18)
• Can form resting structures (cysts)
– All genera produce extensive capsules or slime
layers (Figure 17.19)
• Believed to be important in protecting nitrogenase
from O2
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Figure 17.18
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Figure 17.19
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17.9 Free-Living Aerobic Nitrogen-Fixing
Bacteria
• Additional genera of free-living N2 fixers include
acid-tolerant microbes
– Examples: Azomonas and Derxia (Figure 17.20)
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Figure 17.20
Bipolar lipid
bodies
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17.10 Neisseria, Chromobacterium,
and Relatives
• Neisseria, Chromobacterium, and their
relatives can be isolated from animals, and
some species of this group are pathogenic
(Figure 17.21)
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Figure 17.21
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17.11 Enteric Bacteria
• Enteric bacteria (Figure 17.22)
– Phylogenetic group within the
Gammaproteobacteria
– Facultative aerobes
– Motile or nonmotile, nonsporulating rods
– Possess relatively simple nutritional
requirements
– Ferment sugars to a variety of end products
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Figure 17.22
© 2012 Pearson Education, Inc.
17.11 Enteric Bacteria
• Enteric bacteria can be separated into two broad
groups by the type and proportion of
fermentation products generated by anaerobic
fermentation of glucose (Figure 17.23)
– Mixed-acid fermenters
– 2,3-butanediol fermenters
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Figure 17.23
Glucose
Glycolysis
Pyruvate
Lactate
CO2
Uninoculated tube
Succinate
Ethanol
Acetyl CoA
Acid  gas
reaction
(H2  CO2)
Acetate

CO2
Formate
H2
Gas collection tube
Mixed-acid fermentation (for example, Escherichia coli)
Glucose
Glycolysis
Pyruvate
2,3-Butanediol  CO2
Ethanol
Lactate
Succinate
Weak acid
 strong
gas reaction
Acetate
CO2  H2
Butanediol color reaction
Butanediol fermentation (for example, Enterobacter aerogenes)
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17.11 Enteric Bacteria
• Escherichia
– Universal inhabitants of intestinal tract of
humans and warm-blooded animals
• Synthesize vitamins for host
– Some strains are pathogenic
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17.11 Enteric Bacteria
• Salmonella and Shigella
– Closely related to Escherichia
– Usually pathogenic
– Salmonella characterized immunologically by
surface antigens
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17.11 Enteric Bacteria
• Proteus
– Genus containing rapidly motile cells; capable
of swarming (Figure 17.24)
– Frequent cause of urinary tract infections in
humans
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Figure 17.24
© 2012 Pearson Education, Inc.
17.11 Enteric Bacteria
• Butanediol fermenters are a closely related group
of organisms
– Some capable of pigment production (Figure 17.25)
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Figure 17.25
© 2012 Pearson Education, Inc.
17.12 Vibrio, Aliivibrio, and Photobacterium
• The Vibrio group
–
–
–
–
Cells are motile, straight or curved rods
Facultative aerobes
Fermentative metabolism
Best-known genera are Vibrio, Aliivibrio, and
Photobacterium
– Most inhabit aquatic environments
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17.12 Vibrio, Aliivibrio, and Photobacterium
• The Vibrio group (cont’d)
– Some are pathogenic
– Some are capable of light production
(bioluminescence; Figure 17.26)
• Catalyzed by luciferase, an O2-dependent
enzyme
• Regulation is mediated by population density
(quorum sensing)
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Figure 17.26
© 2012 Pearson Education, Inc.
17.13 Rickettsias
• Rickettsias (Figure 17.27)
– Small, coccoid or rod-shaped cells
– Most are obligate intracellular parasites
– Causative agent of several human diseases
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Figure 17.27
© 2012 Pearson Education, Inc.
17.13 Rickettsias
• Wolbachia (Figure 17.28)
– Genus of rod-shaped Alphaproteobacteria
– Intracellular parasites of arthropod insects
• Affect the reproductive fitness of hosts
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Figure 17.28
© 2012 Pearson Education, Inc.
IV. Morphologically Unusual
Proteobacteria
• 17.14 Spirilla
• 17.15 Sheathed Proteobacteria: Sphaerotilus and
Leptothrix
• 17.16 Budding and Prosthecate/Stalked Bacteria
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17.14 Spirilla
• Spirilla (Figure 17.29)
– Group of motile, spiral-shaped Proteobacteria
– Key taxonomic features include
•
•
•
•
•
Cell shape and size
Number of polar flagella
Metabolism
Physiology
Ecology
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Figure 17.29
© 2012 Pearson Education, Inc.
17.14 Spirilla
• Spirilla
– A few are magnetotactic, demonstrating directed
movement in a magnetic field (Figure 17.30)
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Figure 17.30
Flagellum
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17.14 Spirilla
• Spirilla
– Bdellovibrio
•
•
•
•
•
Prey on other bacteria (Figure 17.31)
Two stages of penetration (Figure 17.32)
Obligate aerobes
Members of Deltaproteobacteria
Widespread in soil and water, including
marine environments
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Figure 17.31
© 2012 Pearson Education, Inc.
Figure 17.32
Release of progeny
Prey lysis
(2.5–4 h
postattachment)
Bdellovibrio
Prey
cytoplasm
Elongation
of Bdellovibrio
inside the
bdelloplast
Prey
40–60 min
Attachment
5–20 min
Bdelloplast
Penetration
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Prey periplasmic
space
17.15 Sheathed Proteobacteria:
Sphaerotilus & Leptothrix
• Sheathed Bacteria
– Filamentous Betaproteobacteria
– Unique life cycle in which flagellated swarmer
cells form within a long tube or sheath
• Under unfavorable conditions, swarmer cells
move out to explore new environments
– Common in freshwater habitats rich in organic
matter
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17.15 Sheathed Proteobacteria:
Sphaerotilus & Leptothrix
• Sphaerotilus (Figure 17.33)
– Nutritionally versatile
• Able to use simple organic compounds
– Obligate aerobes
– Cells within the sheath divide by binary fission
• Eventually swarmer cells are liberated from
sheaths
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Figure 17.33
© 2012 Pearson Education, Inc.
17.15 Sheathed Proteobacteria:
Sphaerotilus & Leptothrix
• Sphaerotilus and Leptothrix are able to
precipitate iron oxides (Figure 17.34)
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Figure 17.34
© 2012 Pearson Education, Inc.
17.16 Budding and Prosthecate/Stalked
Bacteria
• Budding and Prosthecate/Stalked Bacteria
– Large and heterogeneous group
– Primarily Alphaproteobacteria
– Form various kinds of cytoplasmic extrusions
bounded by a cell wall (collectively called
prosthecae; Figure 17.35)
– Cell division different from other bacteria
(Figure 17.36)
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Figure 17.35
Holdfast
Prosthecae
Swarmer cell
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Flagellum
Figure 17.36
I. Equal products of cell division:
Binary fission: most bacteria
II. Unequal products of cell division:
1. Simple budding: Pirellula, Blastobacter
2. Budding from Hyphae: Hyphomicrobium, Rhodomicrobium,
Pedomicrobium
3. Cell division of stalked organism: Caulobacter
4. Polar growth without differentiation of cell size:
Rhodopseudomonas, Nitrobacter, Methylosinus
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17.16 Budding and Prosthecate/Stalked
Bacteria
• Budding Bacteria
– Divide as a result of unequal cell growth
(Figure 17.37)
– Two well-studied genera:
• Hyphomicrobium (chemoorganotrophic; Figure
17.38)
• Rhodomicrobium (phototrophic
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Figure 17.37
DNA
Mother cell
Hypha
Hypha lengthens;
DNA replication
Copy of chromosome
enters bud
Chromosome
Bud
Formation of
cross-septum
Septum
DNA in mother cell
replicates again
Cell
separation
Motile
swarmer
maturates
and swims
away
Flagellum
Hypha lengthens
further
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Figure 17.38
Hypha
Mother cell
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17.16 Budding and Prosthecate/Stalked
Bacteria
• Prosthecate and Stalked Bacteria (Figure 17.39)
– Appendaged bacteria that attach to particulate
matter, plant material, and other microbes in
aquatic environments
– Appendages increase surface-to-volume ratio of
the cells
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Figure 17.39
Stalk
Holdfast
Stalk
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17.16 Budding and Prosthecate/Stalked
Bacteria
• Caulobacter
– Chemoorganotroph
– Produces a cytoplasm-filled stalk
– Often seen on surfaces in aquatic environments
with stalks of several cells attached to form
rosettes
– Holdfast structure present on the end of the stalk
used for attachment
– Model system for cell division and development
(Figure 17.40)
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Figure 17.40
Stalk elongation
DNA synthesis
CrossCell
band
division
Synthesis formation
of flagellin
Initiation
Loss of of DNA
flagellum synthesis
Swarmer cell
0
10
Stalked cell
20
30
40
Elongated
stalked cell Predivisional cell
50
Time (min)
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60
70
80
90
17.16 Budding and Prosthecate/Stalked
Bacteria
• Gallionella
– Chemolithotrophic iron-oxidizing bacteria
– Possess twisted stalk-like structure composed
of ferric hydroxide (Figure 17.41)
– Common in waters draining bogs, iron
springs, and other environments rich in Fe2+
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Figure 17.41
© 2012 Pearson Education, Inc.
V. Delta- and Epsilonproteobacteria
• 17.17 Myxobacteria
• 17.18 Sulfate- and Sulfur-Reducing
Proteobacteria
• 17.19 The Epsilonproteobacteria
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17.17 Myxobacteria
• Gliding
– A form of motility exhibited by some bacteria
• Gliding Bacteria
– Are typically either long rods or filaments
– Lack flagella, but can move when in contact
with surfaces
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17.17 Myxobacteria
• Myxobacteria
– Group of gliding bacteria that form multicellular
structures (fruiting bodies) and show complex
developmental life cycles
– Deltaproteobacteria
– Chemoorganotrophic soil bacteria
– Lifestyle includes consumption of dead organic
matter or other bacterial cells
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17.17 Myxobacteria
• Fruiting myxobacteria exhibit complex
behavioral patterns and life cycles
– Vegetative cells are simple, nonflagellated rods
that glide across surfaces (Figure 17.42)
• Obtain nutrients by lysing other bacteria and
utilizing released nutrients
• Under appropriate conditions, vegetative cells
aggregate, construct fruiting bodies, and
undergo differentiation into myxospores (Figure
17.43)
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Figure 17.42
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Figure 17.43
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17.17 Myxobacteria
• The life cycle of fruiting myxobacterium is
complex (Figure 17.45)
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Figure 17.45
Fruiting-body
and myxospore
formation
Mound
of cells
Fruiting
body
Myxospores
Swarming and
aggregation
Chemical
induction
Vegetative
cycle
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Outgrowth of
vegetative cells
Germination
17.18 Sulfate- and Sulfur-Reducing
Proteobacteria
• Dissimilative sulfate- and sulfur-reducing
bacteria
– Over 40 genera of Deltaproteobacteria
– Use SO42 and S0 as electron acceptors, and
organic compounds or H2 as electron donors
• H2S is an end product
• Most obligate anaerobes
• Widespread in aquatic and terrestrial
environments
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17.18 Sulfate- and Sulfur-Reducing
Proteobacteria
• Physiology of sulfate-reducing bacteria
– Group I
• Include Desulfovibrio, Desulfomonas,
Desulfotomaculum, and Desulfobulbus
(Figure 17.48)
• Oxidize lactate, pyruvate, or ethanol to acetate
– Group II
• Include Desulfobacter, Desulfococcus,
Desulfosarcina, and Desulfonema (Figure 17.48)
• Oxidize fatty acids, lactate, succinate, and
benzoate to CO2
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Figure 17.48a
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Figure 17.48b
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Figure 17.48c
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Figure 17.48d
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Figure 17.48e
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Figure 17.48f
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Figure 17.48g
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17.19 The Epsilonproteobacteria
• Epsilonproteobacteria
– Abundant in oxic–anoxic interfaces in sulfurrich environments
• Example: hydrothermal vents
– Many are autotrophs
• Use H2, formate, sulfide, or thiosulfate as
electron donor
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17.19 The Epsilonproteobacteria
• Pathogenic and nonpathogenic representatives
–
–
–
–
Campylobacter and Helicobacter (pathogenic)
Arcobacter (pathogenic)
Sulfurospirillum and Thiovulum (nonpathogenic)
Wolinella succinogenes (found in rumen)
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