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BACTERIA AND ARCHAEA Evolutionary History of Biodiversity

Bacteria and Archaea

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Evolutionary History of Biodiversity. Bacteria and Archaea. Three Domains of Life. Fig. 26-21. EUKARYA. Dinoflagellates. Land plants. Forams. Green algae. Ciliates. Diatoms. Red algae. Amoebas. Cellular slime molds. Euglena. Trypanosomes. Animals. Leishmania. Fungi. Sulfolobus. - PowerPoint PPT Presentation

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Page 1: Bacteria and Archaea

BACTERIA AND ARCHAEA

Evolutionary History of Biodiversity

Page 2: Bacteria and Archaea

Three Domains of Life

Page 3: Bacteria and Archaea

Fig. 26-21

Fungi

EUKARYA

Trypanosomes

Green algaeLand plants

Red algae

ForamsCiliates

Dinoflagellates

Diatoms

Animals

AmoebasCellular slime molds

Leishmania

Euglena

Green nonsulfur bacteriaThermophiles

Halophiles

Methanobacterium

Sulfolobus

ARCHAEA

COMMONANCESTOR

OF ALLLIFE

BACTERIA

(Plastids, includingchloroplasts)

Greensulfur bacteria

(Mitochondrion)

Cyanobacteria

ChlamydiaSpirochetes

Page 4: Bacteria and Archaea

Prokaryote “Before nucleus”

Characteristics: Unicellular 1-5 μm diameter Cell walls -Maintains shape -Provides protection -Prevents lysis in a

hypotonic environment

Page 5: Bacteria and Archaea

Common Shapes of Prokaryotes

Coccus - round Bacillus - rod-shaped Spirillum - spiral-

shaped

Page 6: Bacteria and Archaea

Eubacteria Clustering Diplo - a prefix used with the shape name to indicate

pairing of cells. Strepto - a prefix used with the shape name to

indicate chains. Staphylo - a prefix used with the shape name to

indicate clusters

Page 7: Bacteria and Archaea

Gram Staining Gram-positive bacteria

purple crystal violet stain is trapped by the layer of peptidoglycan which forms the outer layer of the cell.

Gram-negative bacteria outer membrane of

lipopolysaccharides prevents the stain from reaching the peptidoglycan layer.

outer membrane is then permeabilized by acetone treatment, and the pink safranin counterstain is trapped by the peptidoglycan layer

.

Page 8: Bacteria and Archaea

Gram-positive and Gram-negative Bacteria

Page 9: Bacteria and Archaea

Prokaryotes and a Eukaryotic cell

Page 10: Bacteria and Archaea

Fimbriae and Pili

200 nm

Fimbriae

Figure 27.5

Allow bacteria to stick to their substrate or other individuals in a colony

Page 11: Bacteria and Archaea

Prokaryotic Flagella

About half of prokaryotes are motile

Page 12: Bacteria and Archaea

Prokaryotic FlagellaFlagellum

Filament

Hook

Cell wall

Plasmamembrane

Basal apparatus

50 nm

Page 13: Bacteria and Archaea

Generalized reproduction of a prokaryotebinary fission

conjugation

transformation

transduction

1

2

3

4

One cell passes DNA to another through a sex “pilus”

A bacteria takes up DNA from its liquid surroundings

Bacterial viruses carry portions of DNA from one bacteria to another

Like mitosis, DNA replicates and the bacteria divides

The major source of genetic variation in prokaryotes is mutation

Page 14: Bacteria and Archaea

Bacteria can share genetic material!!!!! Transformation

Page 15: Bacteria and Archaea

Bacteria can share genetic material!!!!! Conjugation

Page 16: Bacteria and Archaea

Bacteria can share genetic material!!!!! Transduction

Page 17: Bacteria and Archaea

Plasmids

Page 18: Bacteria and Archaea

Plasmids

Page 19: Bacteria and Archaea

Prokaryote Colonies in Culture

Page 20: Bacteria and Archaea

Endospores Bacillus anthracis Can remain viable in harsh

conditions for centuries

Page 21: Bacteria and Archaea
Page 22: Bacteria and Archaea

Oxygen Requirements Obligate aerobes

Must have oxygenCellular Respiration

Obligate anaerobesAre poisoned by oxygenFermentation or anaerobic respiration

Facultative anaerobesUse oxygen if it is availableNo oxygen – fermentation

Nitrogen FixationUse atmospheric nitrogen as a direct source of nitrogen.

N2 NH4+

Page 23: Bacteria and Archaea

One of the most independent organisms on earth: Cyanobacteria (Anabaena)

Page 24: Bacteria and Archaea

Cyanobacteria

Gloeothece Nostoc

Fischerella Calothrix

Page 25: Bacteria and Archaea
Page 26: Bacteria and Archaea

Basic Archaeal Shapes : At far left, Methanococcus janaschii, a coccus form with numerous flagella attached to one side. At left center, Methanosarcina barkeri, a lobed coccus form lacking flagella. At right center, Methanothermus fervidus, a short bacillus form without flagella. At far right, Methanobacterium thermoautotrophicum, an elongate bacillus form.

Archaea

Page 27: Bacteria and Archaea

Basic Archaeal Structure : The three primary regions of an archaeal cell are the cytoplasm, cell membrane, and cell wall. Above, these three regions are labeled, with an enlargement at right of the cell membrane structure. Archaeal cell membranes are chemically different from all other living things, including a "backwards" glycerol molecule and isoprene derivatives in place of fatty acids.

Archaea

Page 28: Bacteria and Archaea

The side chains in the phospholipids of bacteria and eukaryotes are fatty acids, chains of usually 16 to 18 carbon atoms. Archaea do not use fatty acids to build their membrane phospholipids. Instead, they have side chains of 20 carbon atoms built from isoprene.

Archaea

Page 29: Bacteria and Archaea

Archaebacteria Methanogens

Anaerobic bacteria (oxygen is a poison) Produce energy by converting H2 & CO2 into methane gas. Live in swamps & marshes

Extreme Halophiles

“Salt-loving" bacteria use salt to generate ATP for energy.

Thermoacidophiles: Live in extremely acidic environments (pH less than 2) extremely high temperatures (up to 110o C). e.g. geothermal springs at Yellowstone National Park.

Page 30: Bacteria and Archaea

Archaebacteria

Page 31: Bacteria and Archaea

Bacteria are the decomposers in ecosystems. Some bacteria are symbiotic and live in

association with other organisms. The bacteria that reside in the human intestinal

tract are mutualistic (both benefit); commensalistic (no harm, no benefit) bacteria reside on our skin; and parasitic (only they benefit, we suffer) bacteria cause a wide variety of diseases.

The cyanobacteria are photosynthetic in the same manner as plants.

Prokaryotes Crucial to the Environment

Page 32: Bacteria and Archaea

Importance to Humans Associated with good health – natural part of flora Nitrogen fixation Recycling nutrients

Sewage Treatment Decomposers, breaking down the remains of organic matter in dead

plant and animal waste. Used to help clean up environmental disasters caused by humans, such

as chemical and oil spills Foods and medicines

sour cream, yogurt, cottage cheese, sauerkraut and pickles, wine antibiotics

Page 33: Bacteria and Archaea

How bacteria cause disease Some bacteria produce toxins that can damage

cells. Endotoxin - made up of lipids and carbohydrates associated with the

outer membrane of gram-negative bacteria. These toxins are some of the strongest poisons known to man and cause violent reactions in host organisms.

Exotoxin - proteins produced inside gram-positive bacteria cells and secreted into the environment. These toxins usually produce fever, weakness, and capillary damage.

Some bacterial proteins cause hypersensitivity reactions which can result in serious illness.

Page 34: Bacteria and Archaea

Antibiotics

Penicillin was the first antibiotic. It is highly effective against Gram+ bacteria, but much less so against Gram- bacteria.

Attacks the sugars that hold the capsule together.

Many bacteria are resistant to antibiotics. High mutation rates and misuse of antibiotics has caused a serious health threat that continues to escalate.

Page 35: Bacteria and Archaea

Antibiotic Resistance When a population of bacteria is exposed to an Antibiotic,

the most susceptible DIE.

A Few Mutant bacteria that are resistant to the Antibiotic may continue to grow.

A Resistant Population then grows from these Mutant

Bacteria through reproduction and genetic recombination.

These new Population are Antibiotic-Resistant. This has resulted from the Over Use of Antibiotics. Many diseases that were once easy to treat are becoming more difficult to treat.

Page 36: Bacteria and Archaea

Antibiotics

Page 37: Bacteria and Archaea

Escherichia coli…bad or good?

E.Coli found in the intestines of most mammals, including humansSynthesizes Vitamin BMost strains harmless

E. Coli 0157:H7 - very toxic, found only in digestive tracts of corn-fed cattle

Believed to have gotten its toxicity by conjugation from Shigella

An estimated 73,000 cases of infection and 61 deaths occur each year in the United States alone

Toxin prevents mRNA production in eukaryotic cells- causes cell death

Adapted to an acidic environment- humans and corn-fed cattle, not grass-fed

Killed at 160 degrees F