THE PROKARYOTES Systematics Focus on animals and plants
- Slides: 42
THE PROKARYOTES
Systematics • Focus on animals and plants – History limited to 20% of evolutionary time • How to classify prokaryotes? Limited in morphological characters
Carl Richard Woese 1928 -2012, USA; Developed system based on 16 S r. RNA in 1977
Carl Woese and George Fox
r. RNA 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
Flow of information in a cell, the central dogma of molecular biology…
• 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
• 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
Ribosomal Function A typical prokaryotic cell may have 10, 000+ ribosomes
Where does r. RNA enter the picture?
Ribosomal Structure Two subunits
Ribosomal subunits= r. RNA molecules + proteins
Prokaryotes Eukaryotes
A modification of Woese from Brock et al. (1994).
The system we propose here will repair the damage that has been the unavoidable consequence of constructing taxonomic systems in ignorance of the likely course of microbial evolution, and on the basis of flawed premises (that life is dichotomously organized; that negative characteristics can define meaningful taxonomies). - Carl R. Woese, Otto Kandler, and Mark L. Wheelis. 1990. Towards a natural system of organisms: Proposal for the domains Archaea, Bacteria, and Eucarya. Proceedings of the National Academy of Sciences. USA. 87: 4576 -4579.
Two different supertrees generated by ML methods for complete genomes of 45 taxa. Daubin et al. 2002
Ciniglia et al. 2004
Lang et al. 2013 Using 24 genes and 3000 taxa
Gram Stain and Structure
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)
Proteobacteria • Disparate functional groups joined by molecular sequences • Likely the source of mitochondria
Alphaproteobacteria • Rikettsias (typhus Rocky Mtn spotted fever • Rhizobias (N-fixing bacteria) • Likely the ancestor of mitochondria was from this group
Gammaproteobacteria • Usually small rods or cocci • Causative agents of Bubonic Plague, Tularemia, Legioner’s Disease, Cholera • Includes Escherichia coli
Spirochaetae
Spirochaetae • Spiraled with internal flagella • Many are free-living • Causative agents of Lyme disease, syphilis, yaws, and relapsing fever
Cyanobacteria
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 overfertilized waters • Source of most atmospheric oxygen, especially prior to eukaryotes
Firmicutae • Lack second outer membrane of Eubacteria • Gram positive
Aphragmabacteria • Tiny, smallest genome of any nonvirus • No walls • Obligate parasites • One causes pneumonia; many plant pathogens
Anoxybacteria • Obligate anaerobes • Causative agents of botulism and tetanus • Botox • Common in soil and animal digestive systems
Endosporobacteria • Produce resistant spores • Many major human pathogens, including anthrax, staph (including methicillin-resistant Staphylococcus aureus), strep • Includes Lactobacillus
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
Deinococcobacteria • Thermophiles • Deinococcus withstands 6, 000 rads (and up to 1500 megarads) • Thermus, found at Yellowstone, enzymes used for PCR
Archaea Differ from the Eubacteria – – Form of ribosomes No murein Different lipids Different RNA polymerase
Crenarchaea • These are the hyperthermophiles • They tend to inhabit very hot environments that are rich in sulfur
Euryarchaeota • Halobacteria • Methanobacteria • Thermoplasmobacteria
The Asgardians Prometheoarcheum, a Lokiarchaeota microbe. Zaremba-Niedzwiedzka et al. 2017. Nature. 541: 353 -358.
Seitz et al. 2019
Viruses • Non-cellular • Usually nucleic acid and protein • Types – – – DNA (ss & ds) RNA (ss & ds) DNA RT RNA RT Prions
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)
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
- Are bears producers or consumers
- Parasitic food chain example
- Animals that eat both plants and animals
- Systematics vs taxonomy
- Taxonomy vs systematics
- Traditional systematics
- Systematics deals with
- Section 2 modern classification
- Porters generic competitive strategies
- Two fundamental business strategies are
- For adult
- Actor focus vs object focus
- Genetic vs physical map
- A keystone species is a species of plants and animals
- Small vacuoles
- Plants and animals reproduction venn diagram
- Amphibians in temperate deciduous forest
- Every living plants and animals must have
- Importance of plants
- Grade 5 natural science term 1
- Central plains industries
- Grassland biome animals and plants
- North central plains plants and animals
- Science class five
- Animal biology revision
- Chromosome number of human
- Texas ecoregions map
- Differences between mitosis in plants and animals
- Lucy and maria twins
- Gas exchange in plants and animals venn diagram
- Non flowering plants characteristics
- Https://a-z-animals.com
- Animals cell structure
- Nonvascular plant
- Non vascular vs vascular plants
- C3 plants vs c4 plants
- Chapter 20 viruses and prokaryotes
- Diff between prokaryotes and eukaryotes
- Chapter 20 viruses and prokaryotes
- Prokaryotes and eukaryotes
- Diff between prokaryotes and eukaryotes
- Multiple choice questions on prokaryotes and eukaryotes
- Gene prediction in prokaryotes and eukaryotes