The Bacteria
Phylogenetic tree of the major lineages
of Bacteria based on 16S ribosomal RNA
Sequence comparisons
The Purple Bacteria,also called Proteobacteria is the
largest and most physiological diverse of all bacteria
Bacteria
? Purple and Green (Anoxygenic Phototrophic Bacteria)
? Cyanobacteria
? Prochlorophytes
? Chemolithotrophs,Nitrifying Bacteria
? Chemolithotrophs,Sulfur- and Iron-Oxidizing Bacteria
? Chemolithotrophs,Hydrogen-Oxidizing Bacteria
? Methanotrophs and Methylotrophs
? Sulfate and Sulfur-Reducing Bacteria
? Homoacetogenic Bacteria
? Budding and Appendaged (Prosthecate) Bacteria
? Spirilla
? Spirochetes
? Gliding Bacteria
? Sheathed Bacteria
Bacteria
? Pseudomonads
? Free-Living Aerobic Nitrogen-Fixing Bacteria
? Acetic Acid Bacteria
? Zymomonas and Chromobacterium
? Vibrio and Related Genera
? Facultatively Aerobic Gram-Negative Rods
? Neisseria and other Gram-Negative Cocci
? Rickettsias
? Clamydias
? Gram-Positive Bacteria,Cocci
? Lactic Acid Bacteria
? Endospore-Forming Gram-Positive Rods and Cocci
? Mycoplasmas
? High GC Gram-Positive Bacteria:,Actinomycetes”
? Coryneform Bacteria
? Propionic Acid Bacteria
? Mycobacteria
? Filamentoud Actinomycetes
Sulfate- and Sulfur-Reducing Bacteria
Representative Sulfate-reducing and sulfur-reducing bacteria
Most are Delta Purple Bacteria
Desulfovibrio desulfuricans
Desulfonema limicola
Desulfobacter postgatei
Desulfobulbus propionicus
Desulfosarcina variabilis
Desulfuromonas acetoxidans
Sulfur-reducing bacteria
Sulfate-Reducing Bacteria
? Strict anaerobes,
? Divided into two broad physiological subgroups:
? Genera in Group I (Desulfovibrio,Desulfomonas,
Desulfotomaculum,Desulfobulbus)
? utilize lactate,pyruvate,ethanol,or certain fatty acids as
carbon and energy sources,reducing sulfate to hydrogen
sulfide
? Genera in Group II (Desulfococcus,Desulfosarcina,
Desulfonema,Desulfonema)
? specialize in the oxidation of fatty acids,particularly
acetate,reducing sulfate to sulfide
? Growth and reduction of sulfate by Desulfotomaculum in certain
canned foods leads to a type of spoilage called sulfide stinker,
? Habitants of anoxic aquatic and terrestrial environments
Sulfur-Reducing Bacteria
? Able to reduce elemental sulfur to sulfide
? Unable to reduce sulfate to sulfide
? Obligate anaerobes
? Utilize only sulfur as an electron acceptor
? Also referred to as dissimilatory sulfur-
reducing bacteria
? Members of the genus Desulfuromonas can
grow anaerobically by coupling the oxidation of
substrates such as acetate to ethanol to the
reduction of elemental sulfur to hydrogen
sulfide
Homoacetogenic Bacteria
? Obligate anaerobes
? Gram-positive
? CO2 as a terminal electron acceptor
? Acetate as the sole product of anaerobic respiration
? Acetyl-CoA pathway convert CO2 to acetate
? Typical species,Acetobacterium woodii and
Clostridium aceticum
Homoacetogenic Bacteria
Mechanism of
autotrophy in
homoacetogenic,
sulfate-reducing
and methanogenic
bacteria
Reactions of the Acetyl-CoA Pathway
Budding and Appendaged (Prosthecate) Bacteria
Asticcacaulis biprosthecum Ancalomicrobium adetum
Ancalochloris perfilievii
Stella
Budding and Appendaged (Prosthecate) Bacteria
? Contain various kinds of cytoplasmic extrusions:
? Stalk
? Hyphae
? Appendages
? These kinds of extrusions,which are smaller in diameter
than mature cell,contain cytoplasma,and are bounded by
the cell wall,are called prosthecae (singular prostheca)
? Unequal cell growth,such as polar growth
? Majority is purple bacteria except Planctomyces and Pirella
which are unusual as their cell walls consist mainly of
protein
? Most are aquatic,many live attach to surfaces using
prosthecae
? A stalk is usually a prostheca except in Planctomyces
Budding and Appendaged (Prosthecate) Bacteria
Contrast between cell division
in conventional bacteria and in
budding and stalked bacteria
Budding and Appendaged (Prosthecate) Bacteria
A Caulobacter rosette,The five cells are
attached by their stalks (prosthecae)
Budding and Appendaged (Prosthecate) Bacteria
Stages in the Hyphomicrobium cell cycle
Budding and Appendaged (Prosthecate) Bacteria
Physiology and Ecology
? Hyphomicrobium is a methylotrophic bacteria,widespread in
freshwater,marine and terrestrial habitates.
Photomicrographs of cells of
Hyphomicrobium
SpirillaSpirillum volutans
Spirillum volutans
Spirosoma linguale
Intestinal spirillum
Purple bacteria
Gram-negative
The genus Spirillum
includes only S,volutans
Spirillum volutans is a
large bacteria,micro-
aerobic
Azospirillum lipoferum is a
nitrogen-fixing organism,It
can form a loose symbiotic
relationship with tropical
grasses and grain crops
Aquaspirillum magnetotacticum
has magnetotaxis ability
Spirilla
? Aquaspirillum
magnetotacticum
contains particles of
Fe3O4 (magnetite)
called magnetosomes
arranged in a chain
Auqasirillum magnetotacticum
Spirilla,Bdellovibrio
Bdellovibrio bacteriovorus
Spirilla,Bdellovibrio
? Preying on other bacteria
? Attack and develop intraperiplasmically
? A wide variety of gram-negative bacteria
can be attacked by a single Bdellovibrio
species
? Gram-positive cells are not attacked
? Obligate aerobe,purple bacteria (delta
group)
Spirilla,Bdellovibrio bacteriovorus
Developmental Cycle
Spirochetes
? Typically slender,flexuous,helical in shape,often rather long
? Axial fibrils or axial filaments are attached to the cell poles and
wrapped around the coiled protoplasmic cylinder.
? Both the axial fibrils and the protoplasmic cylinder are
surrounded by a three-layered membrane called the outer sheath
or outer cell envelope
Spirochaeta stenostrepta
Spirochaeta plicatilis
Treponema pallidum
causes syphilis diseases
Spirochetes
? Arrangement of the protoplasmic cylinder,axial fibrils,and external sheath
? The manner in which the rotation of the rigid axial fibril can generate rotation.
Spirochaeta zuelzerae
Spirochetes,Classification
? Six genera (based on habitat,pathogenicity,and morphological,
physiological characteristics):
? Spirochaeta
? Cristispira
? Treponema (Host in human,causes sexual disease syphilis)
? Leptospira (L,Interrogans causes nephritis and jaundice)
? Leptonema
? Borrelia (B,recurrentis causes relapsing fever)
Cristispira
Spirochetes
? Morphology of Treponema saccharophilum
Treponema saccharophilum
Gliding Bacteria
? No flagella but can move when in contact with surfaces
? Gram-negative,purple bacteria,some are Bacteroides-Flavobacterium
? Myxobacteria can form multicellular structures called fruiting bodies
Beggiatoa
Thioploca
Filamentou sulfur-oxidizing
bacteria in a small stream
Sulfur-oxidizing bacteria
Gliding Bacteria,Leucothrix
? Chemoorganotrophic,requires both H2S and an organic compounds for growth
? Form gonidia under unfavorable conditions
? May aggregate to form rosette when gonidia have high concentration
Leucothrix mucor
Gliding Bacteria,Fruiting Myxobacteria
Myxococcus fulvus
Mellitangium erectum
Myxococcus stipitatus
Chondromyces crocatus
Stigmatella aurantiaca
Exhibit the most
complex behavioral
patterns and life
cycles of all known
prokaryotes
Gliding Bacteria,Fruiting Myxobacterium
Gliding myxobacterium
Stigmatella aurantiaca
Have rather large
chromosome size
Rely on lysis of other
bacteria for nutritions
Myxospores are more
resistant to drying,
sonic vibration,UV
and heat.
Usually colored by
carotenoid pigments
Gliding Bacteria
Gliding Bacteria
? Myxobacteria have distinct growth morphology
Myxococcus xanthus on agar
Myxococcus fulvus
slime tracks on agar
Fruiting body of
stigmatella aurantiaca
Gliding Bacteria
Fruiting body formation in Chondromyces crocatus
Early stage
Stalk formation
Three stages in head formation
Mature fruiting bodies
Sheathed Bacteria
? Filamentous organisms with a unique life cycle involving
formation of flagellated swarmer cells within a long tube or
sheath
? Under unfavorable conditions,the swarmer cells move out and
become dispersed to new environments,leaving behind the empty
sheath
Sphaerotilus natansActive growth stage
Swarmer cells leaving the sheath
Swarmer cell
Pseudomonads
? Purple bacteria (Proteobacteria),gram-negative
? Polar flagella,aerobic,grow at neutral pH mesophilically
? Chemoorganotrophic,never show a fermentative metabolism
? P,aeruginosa is opportunistic pathogen,some are plant pathogens
Pseudomonas have broad substrate
utilization,some produce polyhydroxy-
butyrate and some synthesize medium-
chain-length polyhydroxyalkanoates,
have been studied in our lab
The Entner-Doudoroff pathway,
the major means of glucose catabolism
in pseudomonads
Free-Living Aerobic Nitrogen-Fixing Bacteria
? Large,gram-negative,obligately aerobic rods,capable of fixing N2 nonsymbiotically
? Azotobacter has the highest respiratory rate of any living organism (purple bacteria)
? Azotobacter cells are very large,almost the size of yeasts,produce cysts
Vegatative cells of Azotobacter vinelandii
Cysts
Azotobacter cysts have low
endogenous respiration and are
resistant to desiccation,
mechanical disintegration,and
UV as well as ionizing radiation
however,they are not especially
heat-resistant
Free-Living Aerobic Nitrogen-Fixing Bacteria
? Major genera,Azotobacter,Azomonas,
Azospirillum and Beijerinckia,Derxia
Colonies of Beijerinckia species growing on a carbohydrate-containing medium
Derxia gummosa encased in slime
Free-Living Aerobic Nitrogen-Fixing Bacteria
? Acid-tolerant,free-living N2-fixing Bacteria
Acid-tolerant,free-living N2-fixing bacteria
Beijerinckia indica
Derxia gummosa
PHB
Acetic Acid Bacteria
? Purple bacteria,gram-negative,aerobic,motile rods,tolerance to low pH
? Carry out incomplete oxidation of alcohols,leading to the accumulation of organic
acids as end products
? With ethanol as a substrate,acetic acid is produced
Acetobacter aceti on calcium carbonate agar
containing ethanol as energy source,The clearing
around the colonies due to the dissolution of calcium
carbonate by the acetic acid produced by the bacteria
Classified as Gluconobacter
Can carry out incomplete
oxidation of higher alcohol
and sugars:
Glucose Gluconic acid
Galactose Galactonic acid
Arabinose Arabonic acid
Sorbitol Sorbose
Ascobic acid
Zymomonas and Chromobacterium
? Facultatively aerobic gram-negative rods,beta purple bacteria
? Chromobacterium violaceum produces a purple pigment violacein,a water-insoluble
pigment that has antibiotic properties and is produced only from tryptophan
? Zymomonas carries out fermentation of sugar to ethanol,used in beverage industry.
A large colony of Chromobacterium violaceum
growing among other colonies on an agar plate
Pigment violacein produced by
various species of the genus
Chromobacterium
Vibrio and Related Genera
Gram-negative,facultatively aerobic rods and curved rods
that possess a fermentative metabolism
Most are aquatic,
The Group contains Vibrio,Aeromonas,Photobacterium
Some can emit light (luciferase),these are associated with fish.
and Plesiomonas
Phylogenetic tree of the major lineages
of Bacteria based on 16S ribosomal RNA
Sequence comparisons
The Purple Bacteria,also called Proteobacteria is the
largest and most physiological diverse of all bacteria
Bacteria
? Purple and Green (Anoxygenic Phototrophic Bacteria)
? Cyanobacteria
? Prochlorophytes
? Chemolithotrophs,Nitrifying Bacteria
? Chemolithotrophs,Sulfur- and Iron-Oxidizing Bacteria
? Chemolithotrophs,Hydrogen-Oxidizing Bacteria
? Methanotrophs and Methylotrophs
? Sulfate and Sulfur-Reducing Bacteria
? Homoacetogenic Bacteria
? Budding and Appendaged (Prosthecate) Bacteria
? Spirilla
? Spirochetes
? Gliding Bacteria
? Sheathed Bacteria
Bacteria
? Pseudomonads
? Free-Living Aerobic Nitrogen-Fixing Bacteria
? Acetic Acid Bacteria
? Zymomonas and Chromobacterium
? Vibrio and Related Genera
? Facultatively Aerobic Gram-Negative Rods
? Neisseria and other Gram-Negative Cocci
? Rickettsias
? Clamydias
? Gram-Positive Bacteria,Cocci
? Lactic Acid Bacteria
? Endospore-Forming Gram-Positive Rods and Cocci
? Mycoplasmas
? High GC Gram-Positive Bacteria:,Actinomycetes”
? Coryneform Bacteria
? Propionic Acid Bacteria
? Mycobacteria
? Filamentoud Actinomycetes
Sulfate- and Sulfur-Reducing Bacteria
Representative Sulfate-reducing and sulfur-reducing bacteria
Most are Delta Purple Bacteria
Desulfovibrio desulfuricans
Desulfonema limicola
Desulfobacter postgatei
Desulfobulbus propionicus
Desulfosarcina variabilis
Desulfuromonas acetoxidans
Sulfur-reducing bacteria
Sulfate-Reducing Bacteria
? Strict anaerobes,
? Divided into two broad physiological subgroups:
? Genera in Group I (Desulfovibrio,Desulfomonas,
Desulfotomaculum,Desulfobulbus)
? utilize lactate,pyruvate,ethanol,or certain fatty acids as
carbon and energy sources,reducing sulfate to hydrogen
sulfide
? Genera in Group II (Desulfococcus,Desulfosarcina,
Desulfonema,Desulfonema)
? specialize in the oxidation of fatty acids,particularly
acetate,reducing sulfate to sulfide
? Growth and reduction of sulfate by Desulfotomaculum in certain
canned foods leads to a type of spoilage called sulfide stinker,
? Habitants of anoxic aquatic and terrestrial environments
Sulfur-Reducing Bacteria
? Able to reduce elemental sulfur to sulfide
? Unable to reduce sulfate to sulfide
? Obligate anaerobes
? Utilize only sulfur as an electron acceptor
? Also referred to as dissimilatory sulfur-
reducing bacteria
? Members of the genus Desulfuromonas can
grow anaerobically by coupling the oxidation of
substrates such as acetate to ethanol to the
reduction of elemental sulfur to hydrogen
sulfide
Homoacetogenic Bacteria
? Obligate anaerobes
? Gram-positive
? CO2 as a terminal electron acceptor
? Acetate as the sole product of anaerobic respiration
? Acetyl-CoA pathway convert CO2 to acetate
? Typical species,Acetobacterium woodii and
Clostridium aceticum
Homoacetogenic Bacteria
Mechanism of
autotrophy in
homoacetogenic,
sulfate-reducing
and methanogenic
bacteria
Reactions of the Acetyl-CoA Pathway
Budding and Appendaged (Prosthecate) Bacteria
Asticcacaulis biprosthecum Ancalomicrobium adetum
Ancalochloris perfilievii
Stella
Budding and Appendaged (Prosthecate) Bacteria
? Contain various kinds of cytoplasmic extrusions:
? Stalk
? Hyphae
? Appendages
? These kinds of extrusions,which are smaller in diameter
than mature cell,contain cytoplasma,and are bounded by
the cell wall,are called prosthecae (singular prostheca)
? Unequal cell growth,such as polar growth
? Majority is purple bacteria except Planctomyces and Pirella
which are unusual as their cell walls consist mainly of
protein
? Most are aquatic,many live attach to surfaces using
prosthecae
? A stalk is usually a prostheca except in Planctomyces
Budding and Appendaged (Prosthecate) Bacteria
Contrast between cell division
in conventional bacteria and in
budding and stalked bacteria
Budding and Appendaged (Prosthecate) Bacteria
A Caulobacter rosette,The five cells are
attached by their stalks (prosthecae)
Budding and Appendaged (Prosthecate) Bacteria
Stages in the Hyphomicrobium cell cycle
Budding and Appendaged (Prosthecate) Bacteria
Physiology and Ecology
? Hyphomicrobium is a methylotrophic bacteria,widespread in
freshwater,marine and terrestrial habitates.
Photomicrographs of cells of
Hyphomicrobium
SpirillaSpirillum volutans
Spirillum volutans
Spirosoma linguale
Intestinal spirillum
Purple bacteria
Gram-negative
The genus Spirillum
includes only S,volutans
Spirillum volutans is a
large bacteria,micro-
aerobic
Azospirillum lipoferum is a
nitrogen-fixing organism,It
can form a loose symbiotic
relationship with tropical
grasses and grain crops
Aquaspirillum magnetotacticum
has magnetotaxis ability
Spirilla
? Aquaspirillum
magnetotacticum
contains particles of
Fe3O4 (magnetite)
called magnetosomes
arranged in a chain
Auqasirillum magnetotacticum
Spirilla,Bdellovibrio
Bdellovibrio bacteriovorus
Spirilla,Bdellovibrio
? Preying on other bacteria
? Attack and develop intraperiplasmically
? A wide variety of gram-negative bacteria
can be attacked by a single Bdellovibrio
species
? Gram-positive cells are not attacked
? Obligate aerobe,purple bacteria (delta
group)
Spirilla,Bdellovibrio bacteriovorus
Developmental Cycle
Spirochetes
? Typically slender,flexuous,helical in shape,often rather long
? Axial fibrils or axial filaments are attached to the cell poles and
wrapped around the coiled protoplasmic cylinder.
? Both the axial fibrils and the protoplasmic cylinder are
surrounded by a three-layered membrane called the outer sheath
or outer cell envelope
Spirochaeta stenostrepta
Spirochaeta plicatilis
Treponema pallidum
causes syphilis diseases
Spirochetes
? Arrangement of the protoplasmic cylinder,axial fibrils,and external sheath
? The manner in which the rotation of the rigid axial fibril can generate rotation.
Spirochaeta zuelzerae
Spirochetes,Classification
? Six genera (based on habitat,pathogenicity,and morphological,
physiological characteristics):
? Spirochaeta
? Cristispira
? Treponema (Host in human,causes sexual disease syphilis)
? Leptospira (L,Interrogans causes nephritis and jaundice)
? Leptonema
? Borrelia (B,recurrentis causes relapsing fever)
Cristispira
Spirochetes
? Morphology of Treponema saccharophilum
Treponema saccharophilum
Gliding Bacteria
? No flagella but can move when in contact with surfaces
? Gram-negative,purple bacteria,some are Bacteroides-Flavobacterium
? Myxobacteria can form multicellular structures called fruiting bodies
Beggiatoa
Thioploca
Filamentou sulfur-oxidizing
bacteria in a small stream
Sulfur-oxidizing bacteria
Gliding Bacteria,Leucothrix
? Chemoorganotrophic,requires both H2S and an organic compounds for growth
? Form gonidia under unfavorable conditions
? May aggregate to form rosette when gonidia have high concentration
Leucothrix mucor
Gliding Bacteria,Fruiting Myxobacteria
Myxococcus fulvus
Mellitangium erectum
Myxococcus stipitatus
Chondromyces crocatus
Stigmatella aurantiaca
Exhibit the most
complex behavioral
patterns and life
cycles of all known
prokaryotes
Gliding Bacteria,Fruiting Myxobacterium
Gliding myxobacterium
Stigmatella aurantiaca
Have rather large
chromosome size
Rely on lysis of other
bacteria for nutritions
Myxospores are more
resistant to drying,
sonic vibration,UV
and heat.
Usually colored by
carotenoid pigments
Gliding Bacteria
Gliding Bacteria
? Myxobacteria have distinct growth morphology
Myxococcus xanthus on agar
Myxococcus fulvus
slime tracks on agar
Fruiting body of
stigmatella aurantiaca
Gliding Bacteria
Fruiting body formation in Chondromyces crocatus
Early stage
Stalk formation
Three stages in head formation
Mature fruiting bodies
Sheathed Bacteria
? Filamentous organisms with a unique life cycle involving
formation of flagellated swarmer cells within a long tube or
sheath
? Under unfavorable conditions,the swarmer cells move out and
become dispersed to new environments,leaving behind the empty
sheath
Sphaerotilus natansActive growth stage
Swarmer cells leaving the sheath
Swarmer cell
Pseudomonads
? Purple bacteria (Proteobacteria),gram-negative
? Polar flagella,aerobic,grow at neutral pH mesophilically
? Chemoorganotrophic,never show a fermentative metabolism
? P,aeruginosa is opportunistic pathogen,some are plant pathogens
Pseudomonas have broad substrate
utilization,some produce polyhydroxy-
butyrate and some synthesize medium-
chain-length polyhydroxyalkanoates,
have been studied in our lab
The Entner-Doudoroff pathway,
the major means of glucose catabolism
in pseudomonads
Free-Living Aerobic Nitrogen-Fixing Bacteria
? Large,gram-negative,obligately aerobic rods,capable of fixing N2 nonsymbiotically
? Azotobacter has the highest respiratory rate of any living organism (purple bacteria)
? Azotobacter cells are very large,almost the size of yeasts,produce cysts
Vegatative cells of Azotobacter vinelandii
Cysts
Azotobacter cysts have low
endogenous respiration and are
resistant to desiccation,
mechanical disintegration,and
UV as well as ionizing radiation
however,they are not especially
heat-resistant
Free-Living Aerobic Nitrogen-Fixing Bacteria
? Major genera,Azotobacter,Azomonas,
Azospirillum and Beijerinckia,Derxia
Colonies of Beijerinckia species growing on a carbohydrate-containing medium
Derxia gummosa encased in slime
Free-Living Aerobic Nitrogen-Fixing Bacteria
? Acid-tolerant,free-living N2-fixing Bacteria
Acid-tolerant,free-living N2-fixing bacteria
Beijerinckia indica
Derxia gummosa
PHB
Acetic Acid Bacteria
? Purple bacteria,gram-negative,aerobic,motile rods,tolerance to low pH
? Carry out incomplete oxidation of alcohols,leading to the accumulation of organic
acids as end products
? With ethanol as a substrate,acetic acid is produced
Acetobacter aceti on calcium carbonate agar
containing ethanol as energy source,The clearing
around the colonies due to the dissolution of calcium
carbonate by the acetic acid produced by the bacteria
Classified as Gluconobacter
Can carry out incomplete
oxidation of higher alcohol
and sugars:
Glucose Gluconic acid
Galactose Galactonic acid
Arabinose Arabonic acid
Sorbitol Sorbose
Ascobic acid
Zymomonas and Chromobacterium
? Facultatively aerobic gram-negative rods,beta purple bacteria
? Chromobacterium violaceum produces a purple pigment violacein,a water-insoluble
pigment that has antibiotic properties and is produced only from tryptophan
? Zymomonas carries out fermentation of sugar to ethanol,used in beverage industry.
A large colony of Chromobacterium violaceum
growing among other colonies on an agar plate
Pigment violacein produced by
various species of the genus
Chromobacterium
Vibrio and Related Genera
Gram-negative,facultatively aerobic rods and curved rods
that possess a fermentative metabolism
Most are aquatic,
The Group contains Vibrio,Aeromonas,Photobacterium
Some can emit light (luciferase),these are associated with fish.
and Plesiomonas
