Prokaryotes Prokaryotes - Outline • Prevalence of ... · Prokaryotes Prokaryotes ... Living cyanobacteria Shark Bay, Australia Green River, Wyoming ... • Economic Importance –

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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


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 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


Ancestral Bacteria

Aquificae

Gram +

# of species


27………..few………..few………..


92………..78………..few………..


Group

Thermophiles

Gram Positive


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)


Ancestral Bacteria

Aquificae

Gram +

# of species


27………..few………..few………..


92………..78………..few………..


Group

Thermophiles

Gram Positive


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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


Ancestral Bacteria

Aquificae

Gram +

# of species


27………..few………..few………..


92………..78………..few………..


Group

Thermophiles

Gram Positive


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


Ancestral Bacteria

Aquificae

Gram +

# of species


27………..few………..few………..


92………..78………..few………..


Group

Thermophiles

Gram Positive


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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


Ancestral Bacteria

Aquificae

Gram +

# of species


27………..few………..few………..


92………..78………..few………..


Group

Thermophiles

Gram Positive


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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Plant remnants

Excess Food

Kingdom: Bacteria: Gram Negative Beta Group ChemoautotrophsNitrosomonas & Nitrobacter








SpirochaetesCyanobacteria

Chlamydiae

92………..78………..few………..








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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


Chlamydiae

92………..78………..few………..








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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Chlamydiae

92………..78………..few………..







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

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Prokaryotes Prokaryotes - Outline • Prevalence of ... · Prokaryotes Prokaryotes ... Living cyanobacteria Shark Bay, Australia Green River, Wyoming ... • Economic Importance –