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Prokaryotes Prokaryotes - Outline• Prevalence of Prokaryotes• Structure• Metabolic Diversity• Eubacteria and Archaebacteria• Classification of Prokaryotes• Examples of Prokaryotes & Diseases• Benefits of Prokaryotes
The First Cells
Rocks 3.5- 3.8 billion yrs oldMicrofossils prokaryote like
Living cyanobacteria
Shark Bay, Australia
Green River, Wyoming
Comparison of Eukaryotes & Prokaryotes
NoYesTrue nucleus
ProkaryotesEukaryotesCharacteristic
0.2 – 2 um> 10 umCell Size
Naked, circular DNA+ HistonesChromosomes
TransformationConjugation
MeiosisGenetic recombination
NoYes and NoMulticellularity
Naked circular DNA+ HistonesChromosomes
Binary fissionMitosisCell division
NoYesInternal Compartments
Single flagellin fiber Spinning movement
9+2 microtubulesWhiplike movement
Flagella
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Prokaryotic Features - Mechanisms of diversity
-Transformation = Pick up DNA from the environment-Conjugation = Cell-to-cell DNA transfer-Transduction = DNA transfer by bacteriophages
Sources spontaneously exposure to radiationexposure to chemicals
How often do bacteria mutate? E. coli has 5000 genes 1 mutation/million genes.
… 1 mutation in 200 bacteria… 1 billion bacteria in 1 spoonful of soil… 5 million mutant bacteria in 1 spoonful of soil!
1. Mutation
2. Horizontal gene transfer
Prokaryotic Diversity Horizontal Gene Transfer
2. Transduction by bacteriophage
3. Conjugation & plasmid transfer
Conjugation bridge
1. Transformation
Negative consequences for humansMRSA - Methicillin-resistant Staphylococcus aureus
VRSA - Vancomycin-resistant Staphylococcus aureus
E.coli 157:H7 – harmful traits acquired by transduction & conjugation
Prokaryote Genetic VariationProkaryote Cell Structure
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Prokaryotic internal membranes
Aerobic bacterium Cyanobacterium
Prokaryotic Endospores
Bacillus endospores
Clostridium endospores
Bacillus(bacilli)
Prokaryote ShapesCoccus(Cocci)
Spirillum(Spirillae)
Bacteria Cell Walls: Gram Stain
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Metabolic Diversity in Prokaryotes
AutotrophicUse CO2
Chemoheterotrophic
Photoheterotrophic
Chemolithotrophic
Phototrophic
Oxygenic
Anoxygenic
HeterotrophicUse organic compounds
Prokaryote Energy Metabolism
Autotrophic Metabolism
Heterotrophic Metabolism
ExamplesCarbon Source
Energy Source
Metabolism
H2S oxidizers Green sulfur bacteriaPurple sulfur bacteria
H2O oxidizersCyanobacteria
CO2SunlightPhototroph
Purple non-sulfur bacteriaGreen non-sulfur bacteria
Organic compounds
Sunlight –drives formation of proton gradients
Photoheterotroph
Nitrifying bacteriaDeep sea thermal ventsCO2
S, NH3, NH2, H2S, Fe+2
Chemolithotroph
Most common bacteriaOrganic compounds
Organic compounds
Chemoheterotroph
Prokaryotic Diversity
Prokaryotes the oldest – 3.5 billion years oldsimplest forms of lifeubiquitous 5,000 – 50,000 species
Less than 10% of species are known
Early classification characteristics of prokaryotesEnergy metabolismMotilityUnicells, colonies or filamentsSpore formationImportance as human pathogens or not
Contemporary classificationAmino acid sequencesNucleic acid base composition (G/C content)Nucleic acid hybridizationribosomal RNA sequencingWhole genome sequencing
Criteria to Classify Prokaryotes
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AncestralProkaryote
Domain KingdomArchaea Archaebacteria
Domain KingdomBacteria Bacteria (Eubacteria)
Prokaryote Classification
Start protein synthesis with
Streptomycin sensitivity
Introns
DNA replication &Gene expression
Plasma membrane Phospholipids
Cell wall
Characteristic ArchaebacteriaBacteria
Lack PeptidoglycanPeptidoglycan
Branched chains & ether linkages & monolayers
Straight chains & ester linkages & bilayers
Eukaryote-like ribosomes
Prokaryote pattern
YesNo
NoYes
MethionineFormyl methionine
Comparing Bacteria and Archaebacteria
Prokaryote Classification: Archaebacteria
AncestralProkaryote
Domain KingdomArchaea Archaebacteria
ExtremophilesMethanogensThermophilesHalophilesAcidophiles
BacteriaSulfur – based metabolism…oxidize elemental sulfur to sulfuric acid…reduce elemental sulfur in respiration.…require high temperature (80-105C)
Archaebacteria - Thermoacidophiles
Sulfolobus acidocaldariusDiscovered in 1970 by T. BrockGrowth conditions:
pH 1.0 at 95CHabitat: mud potsOxidizes sulfur to sulfuric acid
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Archaebacteria- halophilesHalobacterium halobium- a photoheterotroph
Light drives proton gradient for ATP synthesis
Solar evaporation ponds: wWhite is sodium carbonate/chloride Red/pink is Halobacterium.
Archaebacteria - methanogensGenus: Methanococcus
Habitat: Deep ocean vents: 2600 meters (3600psi)
Energy source: H2
Carbon source: CO2
Temp: 50 – 86C
Strict Anaerobe
Prokaryote Classification
AncestralProkaryote
Domain KingdomArchaea Archaebacteria
Domain KingdomBacteria Bacteria
Arch
aea
Major Clades of Prokaryotes
Spiro
chae
tes
Cyan
obac
teria
Photo synthetic
Low
G/C
High
G/C
Gram-positive
Alpha beta gamma delta epsilon
Proteobacteria
Aqui
ficae
Ther
mot
ogae
Dein
ococ
cus
Chlo
rofle
xi
Thermophiles
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Prokaryote Classification: Major Clades of Bacteria
Ancestral Bacteria
Aquificae
Gram +
# of species
ThermotogaeDeinococcus
27………..few………..few………..
2475.…….…SpirochaetesCyanobacteriaGreen sulfur bacteria
92………..78………..few………..
Proteobacteria (gram -) 1644………....
Group
Thermophiles
Gram Positive
Gram NegativeChlamydiae
Prokaryote Classification: Major Clades of Bacteria
Ancestral Bacteria
Aquificae
Gram +
# of species
ThermotogaeDeinococcus
27………..few………..few………..
2475.…….…SpirochaetesCyanobacteriaGreen sulfur bacteria
92………..78………..few………..
Proteobacteria (gram -) 1644………....
Group
Thermophiles
Gram Positive
Gram NegativeChlamydiae
Thermus aquaticusThermophileChemoheterotrophTaq polymerase used in PCR
Prokaryote ClassificationAncient Bacteria
AquificaeAquifexHyperthermophile 85CChemoautotrophoxidizes H2 or S
DeinococcusDeincoccus radioduransChemoheterotrophTolerates radiationup to 30,000 Gray units(5Gy kills a human)
Prokaryote Classification: Major Clades of Bacteria
Ancestral Bacteria
Aquificae
Gram +
# of species
ThermotogaeDeinococcus
27………..few………..few………..
2475.…….…SpirochaetesCyanobacteriaGreen sulfur bacteria
92………..78………..few………..
Proteobacteria (gram -) 1644………....
Group
Thermophiles
Gram Positive
Gram NegativeChlamydiae
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Prokaryote Classification: BacteriaGram +
Low G/C
High G/C
Solitary cellsBacillusClostridiumStaphylococcusStreptococcus
Branching filamentsStreptomycesActinomycesMycobacterium tuberculosisMycobacterium leprae
Kingdom: BacteriaBacteria: Gram Positive & Low G/C
Bacillus (gram stained)
Bacillus thuringensisBt protein
bacterial pesticide
Bacillus anthraxisBiological
warfare agent
ClostridiumSpecies(tetani,
botulinum)
Kingdom: BacteriaGram Positive & Low G/C
Streptococcal diseasesDental cariesPneumonia Sore throatImpetigoNecrotizing fasciitisStreptococcal toxic shock syndrome (STSS)
Impetigo
Prokaryote Classification: BacteriaGram +
Low G/C
High G/C
Solitary cellsBacillusClostridiumStaphylococcusStreptococcus
Branching filamentsStreptomycesActinomycesMycobacterium tuberculosisMycobacterium leprae
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Kingdom: BacteriaBacteria: Gram Positive & High G/C
Branching bacteria = Actinomyces & Streptomyces
Actinomyces from oral cavities
Actinomyces/Streptomyces from soilAntibiotics … streptomycin
tetracycline
Streptomyces verticillusproduces bleomycinantitumor antibiotic glycopeptideTreatment of carcinomas & lymphomas
Prokaryote Classification: Major Clades of Bacteria
Ancestral Bacteria
Aquificae
Gram +
# of species
ThermotogaeDeinococcus
27………..few………..few………..
2475.…….…SpirochaetesCyanobacteriaGreen sulfur bacteria
92………..78………..few………..
Proteobacteria (gram -) 1644………....
Group
Thermophiles
Gram Positive
Gram NegativeChlamydiae
Kingdom: Bacteria: Gram Negative Spirochaetes Borrelia burgdorferi
(Lyme disease)
Bullseye rash of lyme disease
Bullseye rash, thenHeadache, stiff neck, fatigue. More serious cases: Encephalitis ArthritisMyocarditis
Prokaryote Classification: Major Clades of Bacteria
Ancestral Bacteria
Aquificae
Gram +
# of species
ThermotogaeDeinococcus
27………..few………..few………..
2475.…….…SpirochaetesCyanobacteriaGreen sulfur bacteria
92………..78………..few………..
Proteobacteria (gram -) 1644………....
Group
Thermophiles
Gram Positive
Gram NegativeChlamydiae
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Filamentous: Anabaena
Filamentous: Spirulina
Colonial: Gloeocapsa
Filamentous: Oscillatoria
Kingdom: Bacteria Cyanobacteria – Oxygenic photosynthetic bacteria
Heterocyst
Kingdom: Bacteria : Gram Negative CyanobacteriaPhotosynthetic bacteria
Genus: Microcystis produces Microcystins liver toxins
Blooms of cyanobacteria
Prokaryote Classification: Major Clades of Bacteria
Ancestral Bacteria
Aquificae
Gram +
# of species
ThermotogaeDeinococcus
27………..few………..few………..
2475.…….…SpirochaetesCyanobacteriaGreen sulfur bacteria
92………..78………..few………..
Proteobacteria (gram -) 1644………....
Group
Thermophiles
Gram Positive
Gram NegativeChlamydiae
ProteobacteriaBeta Nitrosomonas fixes Nitrogen
Gamma Enterics Escherichia coliSalmonellaVibrio cholerae
Alpha Rickettsia… Typhus
Epsilon Helicobacter… Peptic ulcers
DeltaBdellovibrio myxobacteriaglide on mucopolysaccharides
Gram Negative Bacteria
Clades of Gram Negative Bacteria
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ProteobacteriaBeta Nitrosomonas fixes Nitrogen
Gamma Enterics Escherichia coliSalmonellaVibrio cholerae
Alpha Rickettsia… Typhus
Epsilon Helicobacter… Peptic ulcers
DeltaBdellovibrio myxobacteriaglide on mucopolysaccharides
Gram Negative Bacteria
Clades of Gram Negative Bacteria
Plant remnants
Excess Food
Kingdom: Bacteria: Gram Negative Beta Group ChemoautotrophsNitrosomonas & Nitrobacter
ProteobacteriaBeta Nitrosomonas fixes Nitrogen
Gamma Enterics Escherichia coliSalmonellaVibrio cholerae
Alpha Rickettsia… Typhus
Epsilon Helicobacter… Peptic ulcers
DeltaBdellovibrio myxobacteriaglide on mucopolysaccharides
Gram Negative Bacteria
Clades of Gram Negative Bacteria
SpirochaetesCyanobacteria
Chlamydiae
92………..78………..few………..
ProteobacteriaBeta Nitrosomonas fixes Nitrogen
Gamma Enterics Escherichia coliSalmonellaVibrio cholerae
Alpha Rickettsia… Typhus
Epsilon Helicobacter… Peptic ulcers
DeltaBdellovibrio myxobacteriaglide on mucopolysaccharides
Gram Negative Bacteria
Clades of Gram Negative Bacteria
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Kingdom: Bacteria: Gram NegativeGamma Group Enterobacteria Escherichia coli
Hamburger disease caused by Escherichia coli O157:H7Symptoms: Hemorrhagic colitis to kidney failure
Sources:undercooked ground beef raw milkunpasteurized apple juice contaminated water red leaf lettuce alfalfa sproutsvenison jerky
E.coli strain, O157:H7Hemolytic Uremic SyndromeEating undercooked ground beef Drinking contaminated water Drinking unpasteurized (raw) milk Working with cattle
Kingdom: Bacteria: Gram NegativeGamma Group Enterobacteria Salmonella
Gastroenteritis fromRaw milkUndercooked poultry
Salmonella typhimuriumDefinitive Type 104 (DT104) –
observed in 1984an antibiotic resistant strain2000 “serotypes” exist
SpirochaetesCyanobacteria
Chlamydiae
92………..78………..few………..
ProteobacteriaBeta Nitrosomonas fixes Nitrogen
Gamma Enterics Escherichia coliSalmonellaVibrio cholerae
Alpha Rickettsia… Typhus
Epsilon Helicobacter… Peptic ulcers
DeltaBdellovibrio myxobacteriaglide on mucopolysaccharides
Gram Negative Bacteria
Clades of Gram Negative Bacteria
hemolymph cells infected with R. rickettsii
Rocky Mountain Lab
Kingdom: Bacteria: Gram NegativeAlpha Group Rickettsias: R. typhi typhus
Rickettsia rickettsii Rocky Mountain spotted fever
Spotted fever rash
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SpirochaetesCyanobacteria
Chlamydiae
92………..78………..few………..
ProteobacteriaBeta Nitrosomonas fixes Nitrogen
Gamma Enterics Escherichia coliSalmonellaVibrio cholerae
Alpha Rickettsia… Typhus
Epsilon Helicobacter… Peptic ulcers
DeltaBdellovibrio myxobacteriaglide on mucopolysaccharides
Gram Negative Bacteria
Clades of Gram Negative Bacteria Kingdom: Bacteria: Gram NegativeEpsilon Group Helicobacter pilori Peptic Ulcers
Kingdom: Bacteria: Gram Negative Delta Group gliding bacteria & Bdellovibrios
Myxobacteria (gliding bacteria)1. soil bacteria2. some utilize cellulose3. secrete antibiotics to kill
other bacteria
Bdellovibrios1. bacteria that parasitize bacteria2. bore holes through gram- walls3. enter cells and digest contents
Bdellovibrio
Importance of Bacteria• Disease
• Ecology– Decomposers– Producers
• Economic Importance– Genetic engineering– Industrial chemicals: acetic acid, lactic acid– Drugs: streptomycin, erythromycin– Environmental cleanup: oil-degrading bacteria