Introduction to Microbiology

1. Introduction to Microbiology Dr Paul Brown paul.brown@uwimona.edu.jm 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