Welcome to Health Sciences Microbiology BIO 732

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Welcome to Health Sciences MicrobiologyBIO 732
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History of microbiologyChapter 1
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The Early Years of Microbiology

• Antoni van Leeuwenhoek (Father of Microbiology-
  Dad)
• Began making and looking through simple
  microscopes
• Often made a new microscope for each specimen
• Examined water and visualized tiny animals,
  fungi, algae, and single celled protozoa
  animalcules
• By end of 19th century, these organisms were
  called microorganisms

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Major groups of microorganisms we will study

• Bacteria (bacteriology)
• Viruses (virology)
• Fungi (mycology)
• Protozoa (protozoology)
• Helminths and protozoa (parasitology)
• Algae (phycology)

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Fungi

• Eukaryotic (have membrane-bound nucleus)
• Obtain food from other organisms
• Possess cell walls
• Composed of
• Molds multicellular have hyphae reproduce by
  sexual and asexual spores
• Yeasts unicellular reproduce asexually by
  budding some produce sexual spores

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Examples of Fungi
Figure 1.4a
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Examples of Fungi
Figure 1.4b
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Protozoa

• Single-celled eukaryotes
• Similar to animals in their nutritional needs and
  cellular structure
• Typically live freely in water some live inside
  animal hosts
• Most reproduce asexually some reproduce sexually
• Most are capable of locomotion by
• Pseudopodia cell extensions that flow in
  direction of travel
• Cilia numerous, short, hairlike protrusions
  that propel organisms through environment
• Flagella extensions of a cell that are fewer,
  longer, and more whiplike than cilia

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Examples of Protozoa
Figure 1.5a
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Examples of Protozoa
Figure 1.5b
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Examples of Protozoa
Figure 1.5c
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Algae

• Unicellular or multicellular
• Photosynthetic
• Simple reproductive structures
• Categorized on the basis of pigmentation, storage
  products, and composition of cell wall

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Examples of Algae
Figure 1.6a
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Examples of Algae
Figure 1.6b
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Prokaryotes Bacteria and Archaea

• Unicellular and lack nuclei
• Much smaller than eukaryotes
• Found everywhere there is sufficient moisture
  some found in extreme environments
• Reproduce asexually
• Two kinds
• Bacteria cell walls contain peptidoglycan some
  lack cell walls most do not cause disease and
  some are beneficial
• Archaea cell walls composed of polymers other
  than peptidoglycan

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Examples of Prokaryotes
Figure 1.7
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Other Organisms of Importance to Microbiologists
(helminths)
Figure 1.8
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Other Organisms of Importance to Microbiologists
(viruses)
Figure 1.9
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Microbes in your life

• Disease
• Normal Flora
• Normal inhabitants of ourselves and our
  surroundings. Often unnoted, often helpful
• Food
• Production
• Spoilage
• Environmental roles
• Basis of marine and freshwater food chains
• Recycling of chemical elements in the biosphere
• Industrial uses (production of antimicrobials,
  enzymes, dyes, organic acids, etc.)
• Genetic engineering

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The Golden Age of Microbiology (1850-1915)
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What Causes Disease?

• Pasteur developed germ theory of disease
• Robert Koch studied causative agents of disease
• Anthrax
• Examined colonies of microorganisms

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Pasteur and the Defeat of Spontaneous Generation

• Louis Pasteur (1822-1895)
• Discovered that alcoholic fermentation was a
  biologically mediated process (originally thought
  to be purely chemical)
• Disproved theory of spontaneous generation
• Led to the development of methods for controlling
  the growth of microorganisms
• Developed vaccines for anthrax, fowl cholera, and
  rabies

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The Defeat of Spontaneous Generation Pasteurs
Experiment
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The Scientific Method

• Debate over spontaneous generation led in part to
  development of scientific method
• A group of observations leads scientist to ask
  question about some phenomenon
• The scientist generates hypothesis (potential
  answer to question)
• The scientist designs and conducts experiment to
  test hypothesis
• Based on observed results of experiment,
  scientist either accepts, rejects, or modifies
  hypothesis

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What Causes Fermentation?

• Spoiled wine threatening livelihood of vintners,
  so they funded research into how to promote
  production of alcohol, but prevent spoilage by
  acid during fermentation
• Some believed air caused fermentation reactions,
  while others insisted living organisms caused
  fermentation
• This debate also linked to debate over
  spontaneous generation

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Pasteurs Experiments on Pasteurization
Figure 1.14
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Robert Koch

• Robert Koch (1843-1910)
• Definitively demonstrated the link between
  microbes and infectious diseases
• Identified causative agents of anthrax and
  tuberculosis
• Developed techniques (solid media) for obtaining
  pure cultures of microbes, some still in
  existence today
• Awarded Nobel Prize for Physiology and Medicine
  in 1905
• Kochs postulates

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Kochs Postulates

• Suspected causative agent must be found in every
  case of the disease and be absent from healthy
  hosts
• Agent must be isolated and grown outside the host
• When agent is introduced into a healthy,
  susceptible host, the host must get the disease
• Same agent must be reisolated from diseased
  experimental host

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Kochs Postulates
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Kochs Postulates
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Classification

• 3 Domains
• Bacteria
• Archaea
• Eukarya
• Binomial Nomenclature
• Genus species Escherichia coli
• Hierarchy of taxonomic units
• Domain ? Kingdom ? Phylum ? Class ? Order ?
  Family ? Genus ? species