Introduction to Microbiology

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Introduction to Microbiology

• Dr Paul Brown
• paul.brown_at_uwimona.edu.jm
• BC10M Introductory Biochemistry
• Lecture 1

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Teaching Objectives

• To give an overview of the history of
  Microbiology
• To introduce the following
• The extent of the microbial world
• Microscopy theory
• Fundamental and quantitative techniques
• Bacterial and viral growth characteristics
• Microbial phylogenetic and metabolic diversity

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Learning OutcomesI

• At the end of this section, students will have an
  appreciation of /or be able to
• The important developments in Microbiology
• Describe basic and specialised microscopy
  techniques and their applications
• The extent of the microbial world
• Describe the important differences between
  prokaryotes (Bacteria and Archaea) and eukaryotes

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Learning OutcomesII

• At the end of this section, students should be
  able to
• Describe basic and specialized techniques for
  quantifying microbial growth
• Summarize the process of bacterial and viral
  reproduction and describe the dynamics of a
  bacterial growth curve and the plaque assay
• Indicate how bacteria are divided into groups
  according to their phylogeny /or metabolism

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Lecture Plan

• Scope of Microbiology
• Extent of the microbial world
• History of Microbiology
• Techniques
• Microscopy and Staining
• Pure culture methods
• Quantitative methods
• Microbial growth curve
• Plaque assay
• Microbial diversity
• Phylogeny
• Substrate utilization

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References

• Madigan et al. Brocks Biology of Microorganisms
  9th, 10th eds.
• Prescott et al., Microbiology, 3rd, 4th eds.
• Black, Microbiology, 4th ed.
• Other Microbiology texts

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Introduction

• microbiology - the study of microorganisms
• organisms to small to be seen with the naked eye
• except in large groups
• effects of large numbers often visible
• e.g., chemical reactions in soil horizons
• e.g., toxin and gas production in incompletely
  sterilised food cans
• e.g., disease in animals and plants

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Microbial World

• Viruses
• Bacteria (Eubacteria) and Archaeabacteria
• Fungi (Yeasts and Molds)
• Protozoa
• Microscopic Algae

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Benefits

• Maintain balance of environment (microbial
  ecology)
• Basis of food chain
• Nitrogen fixation
• Photosynthesis
• Digestion, synthesis of vitamins
• Manufacture of food and drink

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Benefits

• Genetic engineering
• Synthesis of chemical products
• Recycling sewage
• Bioremediation use microbes to remove toxins
  (oil spills)
• Use of microbes to control crop pests
• Normal microbiota

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Harmful Effects

• Cause disease (basis for bioterrorism)
• Food spoilage

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Pioneers of Microbiology

• Robert Hooke, UK (1665)
• Proposed the Cell Theory
• Observed cork with crude microscope
• All living things are composed of cells
• Spontaneous generation
• Some forms of life could arise spontaneously from
  non-living matter
• Francesco Redi, IT (1668)
• Redis experiments first to dispprove S.G.

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Pioneers of Microbiology

• Antoni van Leeuwenhoek, DE (1673)
• First observed live microorganisms (animalcules)
• Schleiden and Schwann, DE
• Formulated Cell Theory cells are the fundamental
  units of life and carry out all the basic
  functions of living things
• Pasteur, FR and Tyndall, UK (1861)
• Finally disproved S.G.

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Pioneers of Microbiology

• Louis Pasteur (1822-1895), Chemist
• Fermentation (1857)
• Pasteurization heat liquid enough to kill
  spoilage bacteria (1864)
• Vaccine development rabies
• Proposed the germ theory of disease
• Proposed aseptic techniques (prevent
  contamination by unwanted microbes)
• Director of Pasteur Institute, Paris (1894)

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Pioneers of Microbiology

• Joseph Lister, UK (1867)
• Used phenol (carbolic acid) to disinfect wounds
• First aseptic technique in surgery
• Robert Koch, DE (1876)
• Postulates Germ theory (1876)
• Identified microbes that caused anthrax (1876),
  tuberculosis (1882) and cholera (1883)
• Developed microbiological media streak plates
  for pure culture (1881)

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Kochs Postulates

• The specific causative agent must be found in
  every case of the disease.
• The disease organism must be isolated from the
  lesions of the infected case and maintained in
  pure culture.
• The pure culture, inoculated into a susceptible
  or experimental animal, should produce the
  symptoms of the disease.
• The same bacterium should be re-isolated in pure
  culture from the intentionally infected animal.

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Branches of Microbiology

• Bacteriology study of bacteria
• Mycology study of fungi
• Immunology study of immunity
• Edward Jenner, UK developed vaccination (1798)
• Metchnikoff, RU discovered phagocytes (1884)
• Paul Ehrlich, DE theory of immunity (1890)
• Virology study of viruses
• Beijerinck, NE discovered intracellular
  reproduction of TMV coined the term virus
  (1899)

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Branches of Microbiology

• Parasitology study of protozoa and parasitic
  worms
• Chemotherapy
• Treatment of disease by using chemical means
• Antibiotics produced naturally
• Synthetic drugs
• Paul Ehrlich (1878) used arsenic compounds to
  fight disease magic bullet

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Branches of Microbiology

• Chemotherapy
• Alexander Fleming, Scotland (1928) discovered
  penicillin
• Selman Waksman, Ukraine (1944) discovered
  streptomycin
• Problems
• Toxicity of drugs gt Selective toxicity
• Resistance of bacteria to drugs

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Branches of Microbiology

• Recombinant DNA Technology
• Recombinant DNA
• Genetic engineering/biotechnology
• Microbial genetics mechanism by which microbes
  inherit genes
• Molecular biology structure and function
  (expression) of genes
• Molecular epidemiology/diagnostics

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Branches of Microbiology

• Biotechnology
• GMOs/GEMs for industrial, pharmaceutical and
  agricultural applications
• Improvements of agriculture (plants and animals)
• Gene therapy inserting a missing gene or
  replacing a defective one in human cells