Taxonomy & Phylogeny
Taxonomy – the classification & naming of organisms
Phylogeny – evolutionary history of a group of organisms
5 – Kingdom Classification System
Developed by Robert Whittaker in 1969
- Monenra (bacteria) (No longer used)
- Protista (algae, protozoa, etc.) (No longer used)
Domain System – Developed by Carl Woes in 1978, based on similarities in rRNA
◊Note – There are no Kingdoms in Bacteria & Archaea (Prokaryotes)
Bacterial Species – population of cells w/ similar characteristics
Strains – sub-species ex. 0157-H7
- Extreme halophiles (Halobacterium): Salt environments
- Hyperthermophiles (pyrodictium): Hot environments
- Acidophiles (sulfolobus): Acidic environments
Methanogens (Methanobacterium) → Methane generating archaea CH4
Phylum Proteobacteria Characteristics:
- Largest, most diverse group of bacteria
- Proteo- meaning “many forms”
- Obligate intracellular parasite
- Transmitted by vector – tick (Dermacenter)
- Infects endothelial cells, including those of capillaries & lyces cells which creates the red spots.
- Symptoms: Fever, headache, chills, nausea & spotted non-itchy rash.
Orientia tsutsugamushi – Scrub typhys
- Vector is chiggers (mites)
- endemic to Eastern Asia, Australia, Western Pacific Islands
- Symptoms – Muscle pain
Neisseria gonorrhoeae – Gonorrhea”the clap” (term came from french word for brothel – Clapoir)
- Humans are only host/reservoir
- Virulence Factors – fimbriae & capsules that cause the bacteria to adhere to mucous membranes of host.
Bordetella pertusis – Whooping Cough
- Virulence factors – bacteria attached to lipids in cytoplasmic membranes of tracheal cells via adhesions such as pertussis toxin & hemagglutinin. This causes increased mucus production while paralyzing the cilia of tracheal cells.
- Survives in phagocytes & can travel to other parts of body.
Vibrio Cholerae – Cholera
- Humans become infected by ingesting contaminated food or water
- Virulence factor – causes secretion of water & electrolytes in host
- Environment of human body causes toxins in genes to be expressed → toxins cause intestinal cells to secrete water & electrolytes.
Legionella pneumophila – Legionaire’s Disease
- Got name from outbreak at American legion meeting in Philly in 1970
- Common in water, including condensation in air conditioning units & water towers. Live inside protozoa in fresh water such as rivers.
- Exposure route – Inhalation.
Haemophilus influenzae – Meningitis, pneumoniae
- Obligate intracellular parasite
- colonizes mucus membranes
- Capsules that evade phagocytes
- Type B causes most problems in humans.
pseudomonas auruginosa –
- Opportunistic pathogen, common in soil
- green pigment
Francisella tularensis – tularemia
- intracellular parasite
- reservoirs – rabbits, ticks
- symptoms include buboes, dry cough
Yersina pestis – Plague
- buboes (swollen lymph nodes)
- vector – flea; reservoir – rodents
- 2 types: Bubonic plague & pneumonic plague
- 14th century it killed 1/3 of Europeans & mid 500s AD – late 1700s AD killed 40 million people.
Virulence Factor Definition – characteristics of a pathogenic organism that causes harm to the host
Note – Archaea & Eukarya have histones (proteins associated w/ DNA) Bacteria do not.
Ex Credit: Lichen – fungus & algae &/or cyanobacteria, crusty material found on branches or rocks.
3 Types of Symbiotic Relationships:
- Parasitic – one organism is harmed
- Commensalistic – one organism is neutral
- Mutualistic – both organisms benefit