Taxonomy

Classification of living organisms

• Provides common scientific language
• Allows grouping of unknown organisms
• Based on comparisons, similarities (DNA, rRNA, metabolism...)

Names all living organisms with a Genus species designation (italicized or underlined)

intestinal

Named after Theodor Escherich in 1888; found in the colon

• Hemo - blood
• phil - love
• Agusto Ducrey 1889

Named after Albert L neisser in 1879; causes gonorrhea

• Saccharo-sugar
• myco-mold
• cerevisia-beer or ale

• Stapho-cluster
• kokkus-berry
• Aureus-golden

• Lacto-milk
• kokkus-berry

Named after Kiyoshi Shiga in 1898; European Theater of Operations of the US Army (final e gives proper Latin ending)

Species subdivision

Classifies all known bacteria using criteria such as morphology, cell wall composition, O2 requirements, biochemical testing of enzymes/metabolism

Organism is inoculated into a medium containing a specific sugar; growth and end products of fermentation, including gases, are noted.

Organism us inoculated into a solid medium contain gelatin; liquefaction at room temp or inability to re-solidify at refrigerator temp indicates the presence of proteolytic (protein digesting) enzymes

Hydrogen peroxide is poured over heavy growth of an organism on an agar slant; release of O2 gas bubbles indicated the presence of catalase, which oxidizes H2O2 to H2o and O2

Two or three drops of an oxidase test reagent are added to an organism growing on an agar plate; a color change of the test reagent to blue, purple or black indicated the presence of cytochrome oxidase

Organism is inoculated into citrate agar medium in which citrate is the sole carbon source; an indicator is the medium changes color if citrate is metabolized; use of citrate indicates the presence of the permease complex that transports citrate into the cell

• 5-Kingdom
• 3 Domain

• Traditional
• Plantae Pungi Animalia
• Protista
• Monera

Study PP

• Eubacteria
• Archaeobacteria

• Most common bacteria
• Eg- gm(+), gm(-), all pathogens

• Differ: Cell wall (no peptidoglycan), antibiotic sensitivity, membranes
• Live in extreme environments (thermophiles and halophiles)
• Unusual metabolism (methanogens)
• Most ancient forms of life