Lecture 1 Micro biology.pdf on Lecture #1 Introduction to Microbiology
- 1. Lecture #1 Introduction to Microbiology Monday May 6, 2019 Textbook Chapter #1 Thursday September 5, 2019 Monday January 18, 2021
- 2. What are Microorganisms • Prokaryotes: Bacteria and Archaea • Eukaryotes: Protozoa, Fungi • Viruses: acellular requiring a living host cell to reproduce Prokaryotes Archaea Eukaryotes -Lack a membrane bound nucleus -Single circular chromosome -Able to live in adverse environmental conditions (high salt concentrations, high temperatures and acidic environments) -Contain a membrane bound nucleus and membrane bound organelles -Protozoa and fungi are microbes within this group
- 3. Naming of Microorganisms • Binomial System of Nomenclature: • Genus name followed by a Species name Example: Staphylococcus aureus • Many species often exist within a genus Example: the Bacteroides genus contains greater than 100 species • The genus and species of the bacterium must be italicized or underlined • The name of the bacterium may also written with the first letter of the Genus (capitalized) and the name of the species (not capitalized) • Example: S.aureus
- 5. Why is Microbiology Important • Microorganisms are very important to many areas of human, animal, and plant life • Gave way to the introduction and development of higher life forms (atmospheric oxygen was likely produced by primitive photosynthetic microbes) • Important to degrade organic material and for atmospheric nitrogen fixation in plants • Microorganisms produce antibiotics that are used in clinical practice • Normal bacteria within the human body prevent the growth of harmful bacteria • Used for fermentation in the food industry (beer, wine, yogurt)
- 6. Historical Timeline of Microbiology • 1665: Robert Hooke is the first to see and describe cells following the invention of the microscope which led to the start of the cell theory (all living things are composed of cells) • 1684: Anthoni van Leeuwenhoek used the microscope to view live microbes which he called animalcules
- 7. Spontaneous Generation vs Biogenesis Spontaneous Generation: -Food left for long periods of time will eventually spoil -Microscopic examination reveals that the spoiled food is crawling with bacteria -This theory notes that these bacteria arise spontaneously from non-living matter -Louis Pasteur rejected this theory Biogenesis: -The hypothesis that living matter arises only from pre-existing living matter -It is this theory that is currently accepted
- 8. Historical Timeline of Microbiology • 1864: Louis Pasteur demonstrated aseptic technique using a swan neck flask • Hypothesized that microorganisms responsible for food spoilage likely came from the air and not from spontaneous generation • The results of this experiment demonstrated that spontaneous generation could not occur
- 9. Other Contributions Pasteur Made to the Understanding of Microbiology • It was first thought that air converted sugar into alcohol • Pasteur showed that it is yeast that which convert sugar to alcohol in the absence of air using a process called Fermentation • He determined that you could prevent the souring of milk and beer/wine which occurs when the bacteria present convert sugar into vinegar you could heat the milk/beer/wine which would kill all of the bacteria present and prevent spoilage • This procedure is still used today and is called Pasteurization
- 10. Historical Timeline of Microbiology Continued • 1881: Germ Theory of Disease- This is the belief that microorganisms are responsible for disease • This theory was developed by Robert Koch on the basis that microbes alter the chemical and physical nature of organic material • This led to the development of Kochs Postulates which are used today in order to prove that a specific microbe is responsible for a specific disease
- 11. Historical Timeline of Microbiology Continued • 1798: Edward Jenner- developed the small pox vaccine • Based on the observation that people previously infected with cow pox were immune to small pox • He injected a young boy with cow pox and the boy became mildly ill • It was later discovered that this boy was immune to small pox
- 12. • 1908: Paul Ehrlich- developed the idea of selective toxicity • Selective Toxicity: The ability to either kill or inhibit the growth of pathogenic organisms while leaving the host unharmed • He discovered the first effective anti-microbial Salvarsan which was useful to cure syphilis without damaging host cells Historical Timeline of Microbiology Continued
- 13. • 1929: Alexander Fleming • Discovered that a product of the mold Penicillium chrysogenum was able to inhibit the growth of bacteria on plates contaminated with the mold • This product was Penicillin • This discovery was made by accident but consequently revolutionized modern medicine Historical Timeline of Microbiology Continued