Chromosome - double-stranded
DNA (4700 kbp for Escherichia coli) that contains the "blueprint" for all cell
structure and activity in regions called genes
Plasmids -
some have pieces of extrachromosomal DNA (generally circular)
that contain only a few genes, but can replicate themselves and are exchanged among various species
of bacteria
Endospore -
thick-walled structures that are highly resistant to adverse environmental conditions (high temperature,
drying, oxygen, etc.); generally formed only by bacilli, and then each cell only forms one (endospore
stain)
Capsules -
polysaccharide "coatings"
secreted by cells (act as anchors)
Pili -
long thin protein
(pilin) polymers that act as cell "anchors" to various
surfaces and can assist in attaching bacterial cells to facilitate DNA
transfer from one to the other
Gene exchange - mediated by plasmids via
conjugation, transduction or transformation
Operons - these coordinately-controlled groups of
genes use typical on/off signals (TATA box, Pribnow box,
Shine-Dalgarno sequence, etc.)
Reproduction - asexual, by
binary fission (dividing into two roughly equivalent-sized
daughter cells); called "budding" when daughter cells are unequal
in size
pH - most "prefer" pH 5-8, but some thrive at pH
as low as 3 or as high as 10
salts - some are halophilic (require high salt
concentration for growth)
Absorptive nutrition - versatile, although some
require growth factors
organotrophic
- derive energy and carbon from catabolism of organic
molecules
lithotrophic
- derive energy from catabolism of inorganic
molecules and carbon from carbon dioxide
phototrophic
- derive energy from sunlight and carbon from carbon dioxide
Metabolism - is highly adaptable due largely to use
of inducible genes (especially those in operons) and efficient
feedback control systems for both catabolic and anabolic
pathways
Tricarboxylic acid (TCA) or Kreb's cycle and electron
transport system (ETS) present in respiratory membranes;
many other (sometimes highly specialized) catabolic pathways
are also found
ATP synthesis via:
chemiosmotic mechanisms - utilize proton
gradient and membrane-bound ATP synthase for
phosphorylation via photosynthesis or respiration - some
use final electron acceptors other than oxygen (nitrate,
sulfate, etc.)
substrate-level phosphorylation - all use this
to some extent; fermenters use it exclusively
Gram-negative rods (1.5-4 x 4-40 µm),
spirals, ovoid, bean-shaped; some rods motile
via polar flagella
strictly anaerobic anoxygenicphototrophs
that use the Calvin
cycle for CO2 fixation; have
bacteriochlorophylls and use reduced molecules such as
hydrogen sulfide, sulfur, thiosulfate or hydrogen as
electron source for generation of NADH and NADPH:
purple
sulfur bacteria - Chromatium,
Halorhodospira, Thiocapsa, Thiococcus,
Thiopedia,Thiospirillum are
photolithoautotrophs and often form sulfur
granules inside their cells
Gram-negative rods (0.8-1 x 1-2 µm), coccoid
(0.2-1 µm), spiral (0.3-0.4 µm in diameter),
lobular (1-1.5 µm); may have extensive membrane
complexes in cytoplasm
aerobiclithotrophs
which use carbon dioxide or carbonate as carbon source (via
Calvin cycle) and
derive energy by oxidizing inorganic compounds containing
reduced nitrogen (NH4+, nitrite-)
Sulfur-
and Iron-Oxidizing
Bacteria - Thiobacillus, Beggiatoa, Thioploca,
Thiothrix
Gram-negative rods (0.8-1 x 1-2 µm), coccoid
(0.2-1 µm), spiral (0.3-0.4 µm in diameter),
lobular (1-1.5 µm); may have extensive membrane
complexes in cytoplasm; or filamentous with gliding
motility (Beggiatoa)
aerobiclithotrophs
use carbon dioxide or carbonate as carbon source (via
Calvin cycle) and
derive energy by oxidizing inorganic compounds containing
reduced sulfur (Thiobacillus, Thiomicrospora)
and/or reduced sulfur and iron (Thiobacillus
ferroxidans)
found in soil, sewage
treatment systems, freshwater, and marine
habitats, especially sulfur springs
Gram-negative rods (0.8-1 x 1-2 µm), coccoid
(0.2-1 µm), spiral (0.3-0.4 µm in diameter),
lobular (1-1.5 µm); may have extensive membrane
complexes in cytoplasm
aerobiclithotrophs
which use carbon dioxide or carbonate as carbon source (via
Calvin cycle) and
derive energy by oxidizing inorganic compounds containing
reduced hydrogen (generally hydrogen)
aerobicorganotrophs;
generate energy by oxidizing methane (or methyl groups)
widespread in nature in soil and water
Pseudomonas and the
Pseudomonads- Pseudomonas, Agrobacterium,
Rhizobium, Zymomonas
Gram-negative straight or slightly curved rods
(0.5 x 1.5 to 1.4 x 6 µm); motile (polar flagella)
aerobic and facultative aerobic organotrophs;
respiratory (non-fermentative) metabolism that utilizes the
Entner-Doudoroff pathway for carbohydrate oxidation
(Zymomonas uses the Entner-Doudoroff pathway for
oxidation of glucose to ethanol); versatile use of carbon
and energy sources, including use of nitrate as final
electron acceptor via anaerobic
respiration; Rhizobia are aerobic
organisms which live inside other organisms
free-living to parasitic in animals
(Pseudomonas) and plants (Pseudomonas,
Xanthomonas); Rhizobium is a plant
symbiote; Zymomonas is found in soil and
water; occasionally present in pyogenic infections of
humans and animals
Gram-negative, large, rod to pear-shaped (2-4
µm in diameter)
aerobic or microaerophilicorganotrophicnitrogen-fixers; use organic and amino acids as carbon
and energy source, not carbohydrate; Azotobacter has
fastest rate of oxygen-uptake of any known organism
free-living terrestrial nitrogen-fixers,
including Azospirillum, Azotobacter,
Azomonas
Neisseria,
Chromobacterium, and Relatives - Neisseria,
Chromobacterium
Gram-negative cocci (Neisseria) or
rod-coccoid; generally nonmotile (Moraxella and
Acinetobacter possess twitching
motility); Chromobacterium violaceum has
bright purple pigment
aerobic respiratory (non-fermentative) organotrophs;
oxidase positive; versatile carbon and energy sources;
Chromobacterium ferments a variety of carbohydrates
and produces a violet-colored pigment (violacein) when grown
in the presence of tryptophan
isolated from animals (Neisseria are
generally parasitic, some Branhamella are symbiotic
with humans) or from soil and water
(Acinetobacter); Chromobacterium and
Acinetobacter are occasionally present in pyogenic
infections of humans and animals
Gram-negative, straight rods (0.3-1 x 1-6
µm); nonmotile to motile (peritrichous flagella)
facultative aerobes; oxidase negative; diverse
(including fermentative) organotrophiccatabolism
normal flora and/or parasitic on mammals, birds
and plants
Vibrio and
Photobacterium - Vibrio,
Photobacterium
Gram-negative curved rods (0.3-1 x 1-6 µm);
nonmotile to motile (peritrichous or polar flagella)
facultative aerobes; oxidase positive; diverse
(fermentative) organotrophiccatabolism
typically aquatic (freshwater or marine)
free-living; Vibrio cholerae and Vibrio
parahemolyticus are parasitic on animals, especially humans;
Photobacterium is bioluminescent
Rickettsias
-Coxiella, Rickettsia, Rochalimaea
Gram-negative rod, coccoid, pleomorphic (0.3-0.7
x 1-2 µm); nonmotile
aerobic organotrophs;
Coxiella oxidize glucose; Rickettsia do not
oxidize glucose or organic acids, but obtain ATP from
oxidation of glutamate or glutamine, which they obtain from
the host cell (there is some suggestion that they also
obtain NAD+ and coenzyme A from the host cell), and they
replicate in the cytoplasm of the host cell until it is
loaded with parasites
pathogens - transmitted to humans by arthropods;
Rickettsia are obligate intracellular parasites;
Rochalimaea grow attached to outside of host cell
cytoplasmic membrane
Spirilla - Spirilum,
Bdellovibrio, Campylobacter
Gram-negative; helical to vibrioid (curved =
helical but not long enough to encompass one full helical
turn; 0.2 x 1.4 to 1.7 x 60 µm); motile via flagella
(Spirillum, Aquaspirillum) or nonmotile
(Spirosomaceae, Microcyclus)
aerobic, microaerophilic or facultative
aerobicorganotrophs;
use organic and amino acids as carbon/energy source, not
carbohydrate
Gram-negative; filamentous - chains of cells
surrounded by hollow tubelike structure (sheath) used for
surface attachment (frequently have holdfasts), nutrient
adsorption and protection from predators; unicellular
elements (swarmers) generally motile by subpolar flagella,
some nonmotile (Crenothrix)
aerobicmetal oxidizers; precipitate iron
or manganese on sheath; Lepthothrix oxidizes
manganese, Sphaerotilus doesn't
freshwater (flowing) habitats; polluted streams and
activated
sludge
Budding and
Prosthecate/Stalked Bacteria - Hyphomicrobium,
Caulobacter
Gram-negative rods (0.5-1 x 1-3 µm); mobile
by flagella; heterogeneous group, but reproduce by budding
and/or possess a prostheca (cytoplasmic extrusions such as
stalks, hyphae, or other appendages); motile by flagella;
Hyphomicrobium - stalks & budding; Caulobacter
- stalk with holdfast; reproduces by budding
frequently found in nutrient-poor freshwater
habitats
Gliding
Myxoacteria - Myxococcus, Stigmatella
Gram-negative rods (0.6-0.9 x 3-8 µm) with
gliding
motility and production of fruiting bodies (50-500
µm tall) which contain myxospores (Myxococcus,
Chondromyces)
aerobic respiratory organotrophs;
micropredators which kill other bacteria with antibiotics,
then secrete enzymes to dissolve them
found worldwide in soil, decaying plant material and
animal dung; most abundant in warm areas; also found in
arctic tundra
Gram-negative (although some are Gram-positive
endospore formers); straight, curved, or helical rods
(0.5-1.5 x 3-10 µm)
anaerobicdissimilatoryorganotrophicbacteria which use sulfate or sulfur as electron
acceptors in anaerobic
respiration of organic compounds such as acetate,
which they oxidize via an acetyl-CoA pathway; when they have
a source of hydrogen and carbon dioxide, but no organic
compounds, they can use hydrogenase to generate energy
during lithotrophic
growth
thrive in fresh water sediments and sewage
digestors; important in sulfur cycle; combat acid
rain
Gram-positive, nonmotile cocci (0.2-2.5
µm), single or in variable-sized clusters
(Staphylococcus, Micrococcus) or in chains(Streptococcus) orGram-positive,
usually nonmotile bacilli (0.8 x 2 µm -
Lactobacillus) single or in variable-sized clusters;
nonsporulating
aerobic organotrophs
(Micrococcus); facultatively aerobic or
microaerophilicaerobic organotrophs(Staphylococcus, Streptococcus,
Leuconostoc); anaerobic organotrophs
(Lactobacillus) that lack porphyrins (no cytochromes)
so must obtain energy exclusively by substrate-level
phosphorylation; lactic acid bacteria are:
homofermentative - produce lactic acid as sole
product of fermentative metabolism (Streptococcus,
Pediococcus, Enterococcus,
Lactococcus, some Lactobacillus
species)
heterofermentative - produce other products
(ethanol, etc.) in addition to lactic acid
(Leuconostoc, some Lactobacillus
species)
free in nature, normal flora, parasites
(Staphylococcus, Streptococcus); many lactic
acid bacteria (Lactobacillus, Streptococcus, Leuconostoc)
are useful in food production because of the lactic
acid they generate; Listeria is a pathogen
found in food that enters via the digestive tract and
can cause meningitis
Gram-positiveendosporeforming bacilli
(0.3-2.2 x 1.2-6 µm); usually motile by peritrichous
flagella (Bacillus, Clostridium) orGram-positive gliding rod and motile
spirilla (Heliobacterium - two species produce
endospores) or actively motile rods (Heliobacillus)
orcocci in tetrads or packets of 8 or more
cells (Sporocarcina)
obligately anaerobic organotrophs;
produce acetate as the sole product of sugar fermentation
(to produce 2 acetates plus 2CO2 and
H2) coupled with reduction of carbon dioxide
(via the acetyl-CoA pathway) to form a third acetate
... thus the name homoacetogenic
(the sole or only product of
sugar catabolism is acetate); may also grow lithotrophically
using hydrogen as an energy source (same acetyl-CoA
pathway as above) (Acetobacterium,
Clostridium, Desulfotomaculum)
obligately anaerobicphototrophs
(have bacteriochlorophyll g), but can utilize acetate,
pyruvate, lactate or butyrate as carbon sources for
organotrophic
growth (Heliobacterium)
ubiquitous in nature (soil); Heliobacterium
is found in tropical soils, especially rice
paddies; Bacillus and Clostridium are
important in food spoilage, infectious disease
Gram-"negative" (but only because they
fail to stain Gram-positive as a result
of lacking cell walls) pleomorphic
(0.1-0.25 x 3-150µm); lack cell
wall, possess sterols; most are non-motile,
some have gliding
motility
facultatively aerobic or obligately anaerobic organotrophs;
Mycoplasmataceae require steroids, Acholeplasmataceae
do not
ubiquitous parasites (may have
arisen from Clostridium or
Gram-positive Archaea
High GC, Gram-Positive Bacteria:
Coryneform and
Propionic Acid Bacteria -
Corynebacterium, Arthrobacter, Propionibacterium
Gram-positive; nonmotile straight or slightly
curved bacilli, sometimes with swellings (club-shaped
... Coryneforms); or Gram-positive pleomorphic,
nonsporulating bacilli (0.8 x 2 µm ...
Propionibacterium)
animal or plant pathogens or normal microbiota
(Corynebacterium) or soil saprophytes which
mineralize soil contaminants (Arthrobacter);
Propionibacterium grows free in nature,
normal flora and is useful in food production (swiss
cheese)
High GC, Gram-Positive
Bacteria:Mycobacterium
Gram-positive (weakly), slightly curved or
straight rods (0.2-0.6 x 1-10 µm); cell walls have
long-chain waxes containing mycolic acids (acid-fast)
Filamentous, High GC,
Gram-Positive Bacteria: Streptomyces and other Actinomycetes -
Streptomyces, Actinomyces
Nocardioforms
Gram-variable; Nocardia develop a highly
branched substrate mycelium (hyphae 0.5-1.2 µm in
diameter) that breaks up into rods and cocci, form aerial
hyphae, and produce conidia; others may (Nocardioides) or
may not (Rhodococcus) form aerial hyphae or
produce conidia
world-wide in soil and water; mostly
free-living; Nocardia is pathogenic
Actinomycetes
with Multilocular Sporangia
Gram-positive; 0.5-2 µm diameter hyphae;
clusters of coccoid spores, some motile via tufts of
flagella (Dermatophilus), others non-motile
(Frankia)
facultatively anaerobic or microaerophilic
organotrophs
(non-fermentative)
Dermatophilus is parasitic, causes
streptothrichosis; Frankia is symbiotic
with roots of non-leguminous plants (Alder trees) and
fixes nitrogen
Actinoplanetes
Gram-positive, extensive branched,
non-fragmenting substrate mycelium with 0.2-2.6 µm
diameter hyphae; highly colored; motile spores formed in
sporangia (3-20 x 6-30 µm, spherical-cylindrical,
very irregular) on sporangiophores
found in soil (forest litter to beach sand),
freshwater and marine habitats; important in
mineralization of organics (Pilimelia) and
production of gentamicin (Micromonospora)
Streptomyces and
Related Genera
Gram-positive; aerial hyphae (0.5-2 µm
diameter) which form chains of motile conidio-spores;
mycelium does not undergo fragmentation; variety of
colors
aerobic mesophiles with flexible organotrophic
metabolism; degrade chitin, cellulose, pectin, keratin,
etc.
abundant soil microbes (up to 20% of total)
which are responsible for the odor of soil (geosmin) and
are important in mineralization; Streptomyces also
produce antibiotics (antifungals -amphotericin B and
nystatin; ribosome active antibacterials - streptomycin,
neomycin, erythromycin, tetracycline, chloramphenicol);
some cause diseases such as actinomycetoma
Maduromycetes
Gram-positive; aerial mycelia with
non-fragmenting mycelium which forms pairs or short
chains of arthrospores; some form sporangia
aerobicorganotrophs;
most mesophilic, some thermophilic
parasitic - Actinomadura causes
actinomycetomas in humans
Thermonospora and Related
Genera
Gram-positive; variable morphology; single
heat-sensitive spores on aerial mycelium and/or substrate
mycelium
Gram-negative; 1-10 µm diameter, unicellular
(Anacystis, Synechococcus, Pleurocapsa)
or filamentous (Anabena, Nostoc, Oscillatoria);
gliding
motility; some have gas vesicles for vertical
movement in water
aerobicoxygenic photolithotrophs
with chlorophyll a plus phycobiliproteins in
phycobilisomes they use for light gathering; they use
water as electron source for generation of NADH and NADPH
and generate oxygen; they use the Calvin
cycle to generate carbohydrates; heterocystous
cyanobacteria (Anabena, Nostoc) have
heterocysts which facilitate nitrogen-fixation
responsible for most of the oxygen in the atmosphere
and for some of the nitrogen-fixation; very good at
symbiotic relationships (e.g., the "algae" in most lichens
are Cyanobacteria); ecology,
etc.
Prochlorophytes and
Chloroplasts - Prochloron, Prochlorothrix
Gram-negative; 8-10 µm diameter, spherical
(Prochloron) with extensive thylakoid membrane system
(because it closely resembles them, and is frequently
endosymbiotic, some think Prochloron is the precursor
of chloroplasts); filamentous (Prochlorothrix) with
meager thylakoid membrane development
aerobicoxygenic photolithotrophs
with chlorophyll a or b (but lack phycobiliproteins);
picoplankton is ~1 µm in diameter and has only
chlorophyll b)
Gram-negative coccoid (0.2-1.5 µm); non-motile;
no peptidoglycan
aerobic organotrophs;
most limited catabolic and biosynthetic capabilities of any
known organism; no energy-generating system - obtain ATP and
metabolic intermediates from host cell (energy parasites);
replicate via binary fission of reticulate bodies, which
then differentiate into small, dense cell forms called
elementary bodies, which are specialized for
transmission to a new host
pathogens - obligate intracellular parasites; life
cycle involves elementary and reticulate bodies)
Gram-negative ovoid bacteria with a slender stalk,
pili and a flagellum; cell wall contains protein instead of
peptidoglycan; reproduces by budding and expresses a life
cycle; cells include membrane-bound structures, only some of
which contain the genome (Gemmata obscuriglobus)
facultatively aerobic organotrophs
that ferment or respire sugars
Gram-negative straight, curved or helical rods (0.5
x 0.5-10 µm); nonmotile or motile via flagella
(Bacteroides ... possess sphingolipids) or yellow
pigmented rods (Flavobacterium) that move by gliding
motility utilizing movement of proteins on cell
surface
anaerobicorganotrophs;
Bacteroides ferment many sugars to acetate and
succinate, whereas Flavobacteria ferment glucose
(~exclusively)
commensals in the oral cavity and/or intestinal
tract of humans and other animals, rumen of cattle, etc.
(Bacteroides); freshwater and marine aquatic
environments, and found in foods and food-processing
plants (Flavobacterium)
Cytophaga
Group
(Phylum 9) - Cytophaga, Sporocytophaga, Flexibacter
Cytophaga, Sporocytophaga
Gram-negative long, slender rods (often with
pointed ends) that move by gliding
motility
obligately aerobic organotrophs
that digest cellulose with cellulases that remain
bound to the cell envelope (not secreted)
found on surfaces of the cellulose-containing material
(or fish gills)
Flexibacter
Gram-negative filaments that move by gliding
motility; many possess carotenoids
obligately aerobic organotrophs
that do not digest cellulose ... require complex
media
Gram-negative nonmotile rods, cocci or spirals
(0.5-1.1 µm wide or diameter) often form sulfur granules
outside their cells
obligately anaerobicphotolithotrophs
which have bacteriochlorophylls in chlorosomes they use
for light gathering; they use the reverse
TCA
cycle to generate carbohydrates; they use reduced
molecules such as hydrogen sulfide, sulfur, thiosulfate or
hydrogen as electron source for generation of NADH and
NADPH; some are also photoorganotrophic
found in anaerobic, sulfide-rich zones of lakes and
lake muds
aerobic organotroph
that is highly resistant to radiation damage; the best-known
representative of the thermophilic genusThermus is
Thermus aquaticus, the bacterium from which Taq
polymerase is derived
free in nature, especially near radioactive
materials (Dienococcus) or in hot springs
(Thermus)
Gram-negative motile (gliding) filamentous
bacteria that are thought to be among the most ancient of phototrophs
thermophilic obligately anaerobicphototrophs
(Chloroflexus) which have bacteriochlorophylls in
chlorosomes they use for light gathering; they use the
hydroxypropionate pathway to generate carbohydrates; they use
reduced molecules such as hydrogen sulfide, sulfur, thiosulfate
or hydrogen as electron sources for generation of NADH and
NADPH, but can also grow lithotrophically
or organotrophically
under appropriate conditions; orthermophilic aerobic
organotrophs
(Thermomicrobium) with no glycerol and neither ester-
nor ether-linkages in their membrane lipids
found in anaerobic, sulfide-rich zones of lakes and
lake muds
Gram-negative rod with a sheath-like
envelope (hence the term "toga" in the name)
thermophilic (optimum
temperature for growth is 80C, but can grow at 90C) anaerobic
fermenters (organotrophic) that
catabolize sugars and polysaccharides (starch. etc.)
to produce lactate, acetate, CO2 and H2;
can also grow by anaerobic respiration using H2 as
electron donor and Fe3+ as terminal electron
acceptor
grows around benthic marine hydrothermal vents and
continental hot springs
Gram-negative bacillus with ether-linked
(non-phytanyl) lipids (very Archaea-like!)
strictly anaerobic thermophilic sulfate-reducing
organotroph
with an optimum growth temperature of 70C (most thermophilic
of all known sulfate-reducing bacteria)
grows in high-temperature areas near hot springs,
etc.
Gram-negative hyperthermophilic (optimum
temperature for growth is 85C, but can grow up to
95C ... most thermophilic of all known bacteria) microaerophilic (one
of the few aerobic hyperthermophiles known)
lithotropic (reverse
TCA cycle) bacillus that oxidizes
hydrogen, sulfur or thiosulfate and uses oxygen
(microaerophilic growth) or nitrate (anaerobic
growth) as terminal electron acceptors
submarine volcanic
hot springsbacterium;
most ancient branch of the bacterial phylogenetic
tree
Hydrogenobacter - closely related
to Aquifex and shares many metabolic features with it
... except that Hydrogenobacter is an obligate
aerobe
Thermocrinus
pink filament-forming hyperthermophilic
(optimum
temperature for growth is 80C) bacterium isolated
in Yellowstone National Park (one of the first prokaryotes
isolated by Thomas Brock in the 1960s)
lithotrophic bacillus that oxidizes
hydrogen, thiosulfate or sulfur using O2 as
terminal electron acceptor
NO3-)