Chapter 11
The Prokaryotes
Archae & Bacteria
Classification of Organisms
(quick overview of Ch 10)
Whittaker’s Five-Kingdom System: (Table 10.2)
Procaryotae - (Monera) - procaryotes, unicellular
Protista -eukaryotic, generally unicellular (algae, protozoa)
Fungi - eukaryotic, generally multicellular, saprophytic, chitin
Plantae - eukaryotic, multicellular, photosynthetic
Animalia - eukaryotic, multicellular, ingest food
Woese’s Three Domains Domain - classification level higher than kingdom
Based on comparison of sequences of ribosomal RNA (rRNA)
Archaea: contains the archeabacteria (prokaryotic)
Eubacteria: contains the bacteria (prokaryotic)
Eucarya: contains all the eukaryotic kingdoms (eukaryotic)
Bacterial Classification
Bergey’s Manual of Systematic Bacteriology
(divided into four volumes)
I. Gram-negative bacteria of medical and industrial importance
II. Gram-positive bacteria of medical and industrial importance
III. Other Gram-negative bacteria
IV. Actinomycetes and other Gram-positive bacteria
Division within Bergey’s Manual are based on characteristics such as:
Gram reaction, cell shape, cell arrangement, oxygen requirements,
motility, metabolic properties
Bacterial Groups
(on following slides)
Be familiar with major groups in Table 11.1
Know major characteristics which set each group apart from others
(including habitat and special features)
Be able to identify or place important genera within the
appropriate group
Spirochetes
Gram negative cell wall
helical morphology (corkscrew shape)
Motility by axial filaments similar to flagella, but located inside
the periplasmic space
habitat: aquatic (animal parasites)
Important Spirochetes
Treponema pallidum - causative agent of syphilis (STD)
Borrelia burgdorferi causative agent of Lyme’s disease
(transmitted by deer tick)
Aerobic, motile, helical/vibrioid bacteria
(Proteobacteria)
Gram negative cell wall
Morphology helical, vibrioids (comma shape)
Some fix nitrogen
Habitats: soil and aquatic, human intestinal tract and oral cavity
Important Proteobacteria
Spirillum - a fresh water organism
Azospirillum – nitrogen fixer associated with plant roots
Campylobacter – food borne illness
Bdellovibrio – predator on other bacteria
Gram-negative, aerobic rods
and cocci
Gram negative cell wall
Morphology: rods and cocci
Importance: many industrially, medical, and environmentally
important bacteria
Habitat: soil, water, animal parasites
Important GramPseudomonas
Bordetella
opportunistic infection in burns
whooping & kennel coughs
Burkholderia
Francisella
Legionella
Rhizobium
Legionnaire's disease
Neisseria
STD
Brucella
Agrobacterium
Facultatively anaerobic, Gramnegative rods
Gram negative cell wall
Morphology: Rod shaped
Group contains many important pathogens
Habitats:soil, plants, animal respiratory and intestinal tracts
many in this group known also as enterics (found in human intestine)
Important Facultatively anaerobic,
Gram-negative rods
Important genera include:
Escherichia, Salmonella, Shigella, Klebsiella, Yersinia, Vibrio,
Enterobacter, Hemophilus, Gardnerella, Pasteurella
Anaerobic, Gram-negative rods
Gram negative cell wall
Morphology: rods
Special environmental requirements: obligate anaerobes
Habitat: mostly in intestinal tracts, some in mouth and genital tract
some of the most common organisms in the intestine
Important Anaerobic, Gramnegative rods
Bacteriodes
Fusobacterium
Dissimilatory sulfate-reducing or
sulfur reducing bacteria
Gram negative cell wall
Habitat: found in anaerobic sediments
reduce oxidized forms of sulfur to H2S (hydrogen sulfide)
Important genus: Desulfovibrio
Rickettsias and Chlamydias
Gram negative cell wall
Habitat: obligate intracellular bacteria
many important pathogens (see habitat!)
parasites of arthropods and animals
Important Rikettsia & Chlamydia
Rickettsia
Coxiella
Ehrlichia
Chlamydia (STD)
Mycoplasmas
no cell wall (Gram negative reaction)
pleomorphic (multiple shapes)
parasites of animals, plants, insects
some pathogens
Important genus: Mycoplasma
Gram-positive cocci
Gram positive cell wall
Shape: cocci
some important pathogens and industrial organisms
Habitat: found in soils; skin and mucous membranes of animals
Important genera:
Staphylococcus
Streptococcus
Lactococcus
Enterococcus
Endospore-forming rods & cocci
Gram positive cell wall
Importance: some important pathogens and industrial organisms
Habitats: found in soils; animal intestinal tract
Important organisms:
Bacillus - aerobic or facultative anaerobes
Clostridium (anaerobic)
Regular nonspore-forming
Gram-positive rods
Gram positive cell wall
Shape: rods
Importance: some important pathogens and industrial organisms
Habitats: found in dairy products; genital and oral cavities; animal feces
Important genera
Lactobacillus - forms lactic acid from carbohydrates
Listeria - animal pathogen
Irregular nonspore-forming
Gram-positive rods
Gram positive cell wall
Shape: pleomorphic (variable)
Importance: some important pathogens
Habitat: found in soil; human pathogens
Important genera:
Gardnerella, Corynebacterium, Propionibacterium, Actinomyces
Mycobacteria
Gram positive reaction
important pathogens!
Structural feature: acid-fast (produce mycolic acids in cell wall)
Habitat: found in soil; plants; animals
Important genus: Mycobacterium
Leprosy
Tuberculosis
Nocardioforms
Gram positive cell wall
some pathogens
some are acid-fast
found in soil and animals
form branched filaments, reproduce by fragmentation
Important genus: Nocardia
Pulmonary infection
Mycetoma – a destructive infection of feet/hands
Budding or appendaged bacteria
Gram negative cell wall
contain prosthecae (protrusions such as stalks or buds)
mostly aquatic
Important genera: Hyphomicrobium, Caulobacter
Can grow in low nutrient aquatic environments
Sometimes attach to a host and use excretions as nutrients
Non-photosynthetic, non-fruiting,
gliding bacteria
Gram negative cell wall
special feature: gliding motility
environment: aquatic
Important genera:
Cytophaga - degrades cellulose (name means ‘plant eater’)
Beggiatoa: oxidizes hydrogen sulfide
Gliding, fruiting bacteria
Gram negative cell wall
gliding motility – (leave a slime trail)
cells aggregate to form a fruiting body
environment: soil, dung
Important genera: Myxococcus
When you’re out of
poop, ya gotta slide!
under proper conditions (low nutrient) spores germinate to form
new gliding cells which resemble slime molds
Aerobic chemoautotrophic bacteria
Gram negative cell wall
nitrifying and sulfur-oxidizing bacteria
agriculturally and environmentally important
Environment: soil
Important genera:
Nitrosomonas
Nitrobacter
reduce nitrogen compounds to nitrates
Thiobacillus
reduce sulphur compounds to sulfates
Archaea
Gram reaction varies
not related to bacteria
no peptidoglycan in cell wall
found in anaerobic sediments; in extreme environments
Important genera:
Methanobacterium
Halobacterium
Sulfolobus
methane producers useful in sewage treatment
Anoxygenic photosynthetic
bacteria
Gram negative cell wall
includes green and purple sulfur and nonsulfur bacteria
green and purple sulfur bacteria use H2S as an electron donor
and release sulfur
anaerobic sediments
Important genera:
Chromatium
Rhodospirillum
Chlorobium
Oxygenic photosynthetic bacteria
(cyanobacteria)
Gram negative reaction
produce oxygen during photosynthesis
many species fix nitrogen
aquatic
Important genera:
Chroococcus
Anabaena
Actinomycetes
Gram positive cell wall
branching filaments with reproductive conidiospores
(see fig 11.23 conidiospore = asexual reproductive spores)
many important industrial organisms
soil, some aquatic
Important genera:
Streptomyces - important antibiotic producers
also make a gas (geosmin) ‘musty’ odor of soil
Frankia - involved in nitrogen fixation with plants
Micromonospora – antibiotic producer
Fig 11.23
Lets go play in the lab !