Microbiology Lecture 10 Notes Chapter 10 p. 238-256

Origin of life and evolution as separate questions

Three domains; Eucarya, Bacteria, Archaea

Five kingdom system - animals, plants, fungi, protists, monerans (8 kingdoms?)

Practical and natural classification systems; Morphology/physiology vs. molecular biology

Difficulties in defining a species; interfertility vs. gene flow

Numerical taxonomy; dichotomous keys; serology; phage typing

G+C content analysis, nucleic acid hybridization, molecular probes, DNA sequencing

rRNA, conserved sequences, molecular clocks (fibrinopeptides vs. histone proteins)

"E. coli evolved with mammals"; Coevolution (special case of mutualism?)examples; flowers and pollinators, hosts and pathogens (IgA cleaving proteases)

Molecular probes: important sequences=antibiotic resistance, unique to pathogens, environmentally important released entities, taxonomically significant, toxin-encoding, antibiotic resistant, etc.

Classification to species level; M.S. thesis now $300

Check out http:www.nappc.org/ (North American Pollinator Protection Campaign)

Back of this page= lecture notes from

http://www.sp.uconn.edu/~terry/229sp03/lectures/taxonomy.html

Bergey's Manual of Systematic Bacteriology: The definitive guide to procaryotic taxonomy

First edition published in 1923, now in 9th edition.

Uses both morphological and Physiological characteristics

Very practical system. Use successive "key" features to narrow down

identification

Ex. Gram + or -? Then shape? Then motile or not? etc. Eventually only a few organisms match the process of elimination.

Tenth edition now being published, a major reorganization

Primary emphasis is phylogenetic (based on evolutionary relatedness), not phenetic (groups organisms based on mutual similarity of phenotypic characteristics. Mayor may not correctly match evolutionary grouping)

Example: pathogens are not grouped together, instead they are scattered in different

Five volumes have instructive titles:

1. The Archaea, and the Deeply Branching and Phototrophic Bacteria .

2. The Proteobacteria

3. The Low G + C Gram-positive Bacteria

4. The High G + C Gram-positive Bacteria

5. The Planctomyces, Spirochaetes, Fibrobacters, Bacterioidetes, and Fusobacteria Types of Diversity

Metabolic diversity: heterotrophs vs autotrophs.

Major differences between the metabolic needs of heterotrophic and autotrophic microorganisms, and between catabolic styles such as fermentation vs respiration (aerobic and anaerobic).

Structural diversity: we have seen major differences between gram-positive and gram- negative bacteria, and even more profound structural differences between bacteria and archaea. Other differences include presence or absence of walls, external appendages, endospores, etc.

Morphological diversity: bacilli, cocci, and spirals are 3 common shapes, but also filamentous forms, pleiomorphic forms. Although most bacteria are tiny, there are many varieties of sizes, ranging from submicroscopic up to a few bacteria that can be seen with the naked eye.

Genetic diversity: small ribosomal subunit sequencing has profoundly altered our perception of the extent of genetic diversity. Now that genomes are being sequenced for many microbes, the full extent of this diversity is being understood as never before. The great bulk of life's diversity is not in the eukaryotes, but in the bacteria and archaea.