What are microbes

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What are microbes?
helminths
yeast
viruses
cyanobacteria
protozoa
bacteria
algae
mold
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Taxonomy
http//www.linnean.org/html/history/linnaeus_biogr
aphy.htm
http//www.nhm.ac.uk/library/linn/
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Taxonomy
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Five kingdom system
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Three Domain System
Black, J.G. (2002) Fig. 9.13
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Taxonomical ranks
after Alcamo Fig. 3.4
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Bacterial nomenclature

• Genus species
• e.g.
• Escherichia (genus) coli (species)
• Bacillus subtilis
• Enterococcus faecalis

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Where do bacteria come from?
Palaeolyngbya
chroococcalean form
www.ucmp.berkeley.edu/ bacteria/cyanofr.html
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Where do bacteria live?

• EVERYWHERE! (almost)
• humans host 1014 bacterial cells in 1013 human
  cells!
• NOT found inside tissues (of organisms)

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What do microbes do?

• Eat, grow, and divide!!
• How to accomplish?
• modify metabolism
• make toxins
• structuralmodifications

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Why do we care?

• Disease
• Agriculture
• Food and beverages
• Chemicals
• Basic research
• Biotechnology

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How did microbiology become a science?

• Anthony van Leeuwenhoek (late 1600s)

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Spontaneous generation controversy
www.darwin.museum.ru/site_bac/ etap/etap2_A.htm
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Pasteur Tyndall end spontaneous generation
controversy
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Disease transmission?
miasma
www.ghosthunting.org.uk/ cemetary3.htm
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Fracastoro
seeds of contagion
infection
delpiano.com/millennium/html/ body_fracastoro.html
symptoms
courses
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Semmelweis
www.personal.psu.edu/faculty/ j/e/jel5/micro/art.h
tm
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John Snow
www.soi.city.ac.uk/ dk708/pg1_1.htm
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Germ Theory of Disease
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Joseph Lister
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Koch establishes causative link between B.
anthracis anthrax
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Suspected microbe must be present in EVERY case
of the disease
Diseased subjects
Microbe not typically found in healthy subjects
Kochs Postulates
Must isolate grow pure culture of microbe
Same microbe must be isolated from diseased
experimental host
Cultured microbe must cause disease when
inoculated into a healthy, susceptible host
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Exceptions to Kochs postulates

• Organism cant be cultured
• e.g. Mycobacterium leprae
• Combination of pathogens
• Ethical considerations

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Golden Age of Microbiology Late 1800s
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Whats included in microbiology?
Microbiology
Basic research microbiology
Applied microbiology
In relation to disease
After Black (2002) Microbiology Principles
Explorations, 5th Ed. Table 1.2
By process
By kind of organism
Bacteriology Phycology Mycology Protozoology Paras
itology Virology
Microbial metabolism Microbial genetics Microbial
ecology
Immunology Epidemiology Etiology
Microbialtaxonomy
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Whats included in microbiology?
Microbiology
Basic research microbiology
Applied microbiology
After Black (2002) Microbiology Principles
Explorations, 5th Ed. Table 1.2
Environmental
Disease-related
Industrial
Infection control Chemotherapy
Environmental microbiology
Food/Beverage technology Pharmaceutical
microbiology Genetic engineering