Lecture 2
? 1.5 The Historical Roots of Microbiology
? 1.6 Microbial Diversity and the Advent of
Molecular Microbiology
? 2.1 Elements of Cell and Viral Structure
? 2.2 Arrangement of DNA in Microbial Cells
? 2.3 The Tree of Life
Louis Pasteur ~1860
Where do the microorganisms come from?
Spontaneous generation?
Heat was used to kill the microorganisms in the liquid
When dust was prevented from reaching the sterilized liquid,nor
microorganisms grew in the liquid
Contact with dust resulted in growth of microorganisms in the liquid
-disproved spontaneous generation
Robert Koch,1870s --Proof that microorganisms can cause disease
-“germ theory of disease”
Anthrax,caused by Bacillus anthracis
Organism present in the blood of all diseased animals
-cause or result of the disease?
Figure 1.12
Pure culture
Figure 1.12
Figure 1.12
Conclusion - specific organisms cause specific disease
Koch’s postulates can be extended beyond disease-causing organisms
Figure 1.12
The,Five Kingdoms” of Life
? Plants
? Animals
? Fungi
? Protists (prokaryotes)
? Monera (slime molds,flagellates,Giardia)
? human-centric organization
The Three Domains of Life