BIO205 Microbiology
Lecture Outline 4: Classification of Microbes
I. Taxonomy:
A. Phylogeny:
1. evolutionary history of various groups of organisms
2. taxa are arranged in hierarchies to reveal phylogeny
B. Domains:
1. eukarya
a. kingdoms of animalia, plantae, fungi, protista
2. bacteria
a. prokaryotes with peptidoglycan
3. archaea
a. prokaryotes without peptidoglycan; mostly "extremophiles"
i. methanogens
ii. halophiles
iii. hyperthermophiles
4. three domains based on differences in ribosomes, membrane lipids and antibiotic sensitivity
a. endosymbiotic theory: eukaryotes evolved from prokaryotes living inside one another
C. Nomenclature:
1. Domain, Kingdom (except for bacteria), Phylum, Class, Order, Family, Genus, species.
2. Binomial Nomenclature
a. each organism has a two-part name - Genus species
b. names are derived from Latin or Greek
3. Prokaryotic classification is organized and characterized in "Bergey's Manual"
II. Methods of Classification:
A. Morphology:
1. bacilli, rod, helical, vibrioid, coccoid, filamentous, sheathed, branching, unusual shapes...
B. Differential Staining:
1. Gram, acid-fast...
C. Oxygen Requirements:
1. Strict Aerobe, Strict Anaerobe, Facultative Anaerobe, Microaerophile
D. Biochemical Tests:
1. specific sugar fermentation, H2S production, enzyme activity...
E. Serotyping:
1. use of antisera to identify various strains, especially pathogenic strains of E. coli, Salmonella...
F. Phage Typing:
1. use of bacterial viruses (phages) to identify specific types of bacteria
G. Chemical Composition:
1. cell wall, membrane components, fatty acids, carbohydrates...
H. DNA & RNA Analysis:
1. gene sequence comparisons of specific genes, compares relatedness at genetic level.
This is only a general outline.
There may be material that has been discussed in lecture that is not included in this outline
and there may be material on this outline that has not been discussed in lecture.
Any material discussed in lecture or listed in this outline is "fair game" for the test.