Introduction to Microbiology

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     1  Introduction to Microbiology Dr Paul Brown BC10M: Introductory Biochemistry Lecture 1
     2  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
     3  Learning Outcomes…I 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
     4  Learning Outcomes…II 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
     5  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
     6  References Madigan et al. Brock’s Biology of Microorganisms : 9th, 10th eds. Prescott et al., Microbiology, 3rd, 4th eds. Black, Microbiology, 4th ed. Other Microbiology texts
     7  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
     8  Microbial World Viruses Bacteria (Eubacteria) and Archaeabacteria Fungi (Yeasts and Molds) Protozoa Microscopic Algae
     9  Benefits Maintain balance of environment (microbial ecology) Basis of food chain Nitrogen fixation Photosynthesis Digestion, synthesis of vitamins Manufacture of food and drink
     10  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
     11  Harmful Effects Cause disease (basis for bioterrorism) Food spoilage
     12  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) Redi’s experiments first to dispprove S.G.
     13  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.
     14  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)
     15  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)
     16  Koch’s 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.
     17  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)
     18  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’
     19  Branches of Microbiology Chemotherapy Alexander Fleming, Scotland (1928) discovered penicillin Selman Waksman, Ukraine (1944) discovered streptomycin Problems Toxicity of drugs => Selective toxicity Resistance of bacteria to drugs
     20  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
     21  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