Slide #1.

THE PROKARYOTES
More slides like this


Slide #2.

Systematics • Focus on animals and plants – History limited to 20% of evolutionary time • How to classify prokaryotes? Limited in morphological characters
More slides like this


Slide #3.

Carl Richard Woese 1928-2012, USA; Developed system based on 16S rRNA in 1977
More slides like this


Slide #4.

Carl Woese and George Fox
More slides like this


Slide #5.

rRNA Emile Zuckerkandl (1922-2013); Austria & USA. Molecular biology and molecular clock Linus Carl Pauling (1901-1994) USA Founder of fields like quantum chemistry and molecular biology Suggested that a tree of life might be generated by comparing sequences of biopolymers like RNA Zuckerkandl and Pauling
More slides like this


Slide #6.

Flow of information in a cell…
More slides like this


Slide #7.

• When DNA is transcribed, the result is an RNA molecule DNA molecule Gene 1 Gene 2 Gene 3 DNA strand Transcription RNA Translation Codon Polypeptide Amino acid Figure 10.10
More slides like this


Slide #8.

• When DNA is transcribed, the result is an RNA molecule DNA molecule Gene 1 Gene 2 Gene 3 • RNA is then translated into a sequence of amino acids DNA strand Transcription RNA Translation Codon Polypeptide Amino acid Figure 10.10
More slides like this


Slide #9.

Ribosomal Function A typical prokaryotic cell may have 10,000+ ribosomes
More slides like this


Slide #10.

Where does rRNA enter the picture?
More slides like this


Slide #11.

Ribosomal Structure Two subunits
More slides like this


Slide #12.

Ribosomal subunits= rRNA molecules + proteins
More slides like this


Slide #13.

Prokaryotes Eukaryotes
More slides like this


Slide #14.

What’s the ‘S’? • Svedberg units: a measure of how quickly particles sediment in an ultracentrifuge
More slides like this


Slide #15.

What’s the ‘S’? • Svedberg units: a measure of how quickly particles sediment in an ultracentrifuge • Larger the particle, the greater its S value • Smaller subunit of a ribosome sinks slower than the larger subunit
More slides like this


Slide #16.

Why then does 5S + 23S = 50S?
More slides like this


Slide #17.

Why then does 5S + 23S = 50S? Shape AND size determine sedimentation rate…
More slides like this


Slide #18.

Ribosomal RNA Molecules • Components of the ribosomes of ALL ORGANISMS • Changes in nucleotide sequence indicative of evolutionary history • “highly conserved molecules”… What does this mean?
More slides like this


Slide #19.

Ribosomal Function • PROTEIN SYNTHESIS • Not much room for error! • Disruption of ribosome structure likely to disrupt protein synthesis… Life threatening!
More slides like this


Slide #20.

Practical applications… • Some antibiotics (e.g. erythromycin and streptomycin) work by targeting the 70S ribosomes • Alter shape and prevent bacteria from synthesizing proteins needed to survive • Why are our own ribosomes not affected by the same drugs???
More slides like this


Slide #21.

A modification of Woese from Brock et al. (1994).
More slides like this


Slide #22.

Two different supertrees generated by ML methods for complete genomes of 45 taxa. Daubin et al. 2002
More slides like this


Slide #23.

Ciniglia et al. 2004
More slides like this


Slide #24.

Lang et al. 2013 Using 24 genes and 3000 taxa
More slides like this


Slide #25.

Gram Stain and Structure
More slides like this


Slide #26.

Eubacteria • >9 Kingdoms • Same type of ribosomes • Polysaccharide of outer wall made of murein • Most groups involved in global nutrient cycling • Many of economic importance • Disease • Other functions (e.g. antibiotic producers)
More slides like this


Slide #27.

Proteobacteria • Disparate functional groups joined by molecular sequences • Likely the source of mitochondria
More slides like this


Slide #28.

Alphaproteobacteria • Rikettsias (typhus Rocky Mtn spotted fever • Rhizobias (N-fixing bacteria) • Likely the ancestor of mitochondria was from this group
More slides like this


Slide #29.

Gammaproteobacteria • Usually small rods or cocci • Causative agents of Bubonic Plague, Tuleremia, Legioner’s Disease, Cholera • Includes Escherichia coli
More slides like this


Slide #30.

Spirochaetae
More slides like this


Slide #31.

Spirochaetae • Spiraled with internal flagella • Many are free-living • Causative agents of Lyme disease, syphilis, yaws, and relapsing fever
More slides like this


Slide #32.

Cyanobacteria
More slides like this


Slide #33.

Cyanobacteria • Like free-living chloroplast • Group from which chloroplasts appeared • Form filaments, colonies • Very large for bacteria • Some produce toxins • Many are nuisance algae in over-fertilized waters • Source of most atmospheric oxygen, especially prior to eukaryotes
More slides like this


Slide #34.

Firmicutae • Lack second outer membrane of Eubacteria • Gram positive
More slides like this


Slide #35.

Aphragmabacteria • Tiny, smallest genome of any nonvirus • No walls • Obligate parasites • One causes pneumonia; many plant pathogens
More slides like this


Slide #36.

Anoxybacteria • Obligate anaerobes • Causative agents of botulism and tetanus • Botox • Common in soil and animal digestive systems
More slides like this


Slide #37.

Endosporobacteria • Produce resistant spores • Many major human pathogens, including anthrax, staph (including methicillin-resistant Staphylococcus aureus), strep • Includes Lactobacillus
More slides like this


Slide #38.

Actinobacteria • Many are slow-growing and funguslike • Antibiotic sources (e.g. streptomycin, actinomycin) • Causative agents of leprosy and tuberculosis; diptheria • Bacteria which cause holes in Swiss cheese • Bifida, a necessary commensal in our lower bowel
More slides like this


Slide #39.

Deinococcobacteria • Thermophiles • Deinococcus withstands 6,000 rads (and up to 1500 megarads) • Thermus, found at Yellowstone, enzymes used for PCR
More slides like this


Slide #40.

Archaea Differ from the Eubacteria – – – – Form of ribosomes No murein Different lipids Different RNA polymerase
More slides like this


Slide #41.

Crenarchaea • These are the hyperthermophiles • They tend to inhabit very hot environments that are rich in sulfur
More slides like this


Slide #42.

Euryarchaeota • Halobacteria • Methanobacteria • Thermoplasmobacteria
More slides like this


Slide #43.

Viruses • Non-cellular • Usually nucleic acid and protein • Types – – – – – DNA (ss & ds) RNA (ss & ds) DNA RT RNA RT Prions
More slides like this




Slide #45.

Some Human Viral Diseases • • • • • • • • • • Herpes Smallpox Hepatitis (B, C, D) Yellow Fever Dengue fever West Nile HIV Ebola Rabies Chicken Pox /Shingles • • • • • • • • • • Rubella (German Measles) Influenza Polio Mumps Measles Epstein-Barr Hemorrhagic fever Rota Rhinovirus Transmissible spongiform encephalopathy (TSE)
More slides like this


Slide #46.

Theories on Origin of Viruses • Regressive Hypothesis: cellular parasites of larger cells that became simplified • Cellular Origin Hypothesis: pieces of living cells that can replicate (e.g. strands of nucleic acids like plasmids or transposons) • Coevolution Hypothesis: evolved together with the first cells as their parasites
More slides like this