Foundations in Microbiology chapt01_lecture
- 1. Foundations in Microbiology Seventh Edition Chapter 1 The Main Themes of Microbiology Lecture PowerPoint to accompany Talaro Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
- 2. 2 1.1 Microbiology • The study of organisms too small to be seen without magnification • Microorganisms include: – Bacteria – Viruses – Fungi – Protozoa – Helminths (worms) – Algae
- 3. 3 Microbiological Endeavors Table 1.1 • Immunology • Public health microbiology and epidemiology • Food, dairy, and aquatic microbiology • Agricultural Microbiology • Biotechnology • Genetic Engineering and Recombinant DNA Technology
- 4. 4 1.2 Origins of Microorganisms • Bacteria-like organisms have existed on earth for about 3.5 billion years – Prokaryotes (pre-nucleus): Simple cells – Eukaryotes (true nucleus): Complex cells
- 5. 5 Microbial Involvement in Energy and Nutrient Flow • The flow of energy and food through the earth’s ecosystems – Photosynthesis: Light fueled conversion of carbon dioxide to organic material – Decomposition: Breakdown of dead matter and wastes into simple compounds
- 6. 6 1.3 Human Uses of Microorganisms • Biotechnology – Production of foods, drugs, and vaccines • Genetic engineering – Recombinant DNA • Bioremediation
- 8. 8 1.4 Infectious Diseases • Pathogens: Microorganisms that do harm • Nearly 2,000 different microbes cause diseases • 10 B new infections/year worldwide • 12 M deaths from infections/year worldwide
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- 10. 10 Figure 1.4 Worldwide infectious disease statistics
- 11. 11 1.5 Characteristics of Microbes • Two cell lines – Prokaryote – microscopic, unicellular organisms, lack nuclei and membrane-bound organelles – Eukaryote – unicellular (microscopic) and multicellular, nucleus and membrane-bound organelles • Viruses – Acellular, parasitic particles composed of a nucleic acid and protein
- 12. Figure 1.5 Basic structure of cells and viruses 12
- 13. Figure 1.6 The six types of microorganisms 13
- 15. Lifestyles of Microorganisms • Majority live a free existence, are relatively harmless and often beneficial • Many microorganisms have close associations with other organisms – Parasites – Hosts 15
- 16. 16 1.6 Historical Foundations of Microbiology • Thousands of microbiologists, 300 years • Prominent discoveries include: – Microscopy – Scientific method – Development of medical microbiology – Microbiology techniques
- 17. Spontaneous Generation Early belief that some forms of life could arise from vital forces present in nonliving or decomposing matter (flies from manure, etc.)
- 18. 18 Antoni van Leeuwenhoek (1632-1723) • Dutch linen merchant • First to observe living microbes • Single-lens magnified up to 300X Insert figure 1.8
- 19. 19 Insert figure 1.9 (a) microscope
- 20. 20 Scientific Method • Approach taken by scientists to explain a certain natural phenomenon • Form a hypothesis - a tentative explanation that can be supported or refuted – Deductive approach “If…, then….” • A lengthy process of experimentation, analysis, and testing either supports or refutes the hypothesis
- 21. 21 • Results must be published and repeated by other investigators. • If hypothesis is supported by a growing body of evidence and survives rigorous scrutiny, it moves to the next level of confidence - it becomes a theory. • If evidence of a theory is so compelling that the next level of confidence is reached, it becomes a Law or principle.
- 22. The Development of Medical Microbiology • Early experiments led to the realization that microbes are everywhere • This discovery led to immediate applications in medicine – Germ theory of disease: resulted in the use of sterile, aseptic, and pure culture techniques 22
- 23. 23 Discovery of Spores and Sterilization • John Tyndall and Ferdinand Cohn each demonstrated the presence of heat resistant forms of some microbes. – Cohn determined these forms to be heat- resistant bacterial endospores. • Sterility requires the elimination of all life forms including endospores and viruses.
- 24. Figure 1.10 The pattern of deductive reasoning 24
- 25. 25 Development of Aseptic Techniques • The human body is a source of infection – Dr. Oliver Wendell Holmes – observed that mothers of home births had fewer infections than those who gave birth in hospitals – Dr. Ignaz Semmelweis – correlated infections with physicians coming directly from autopsy room to maternity ward
- 26. 26 • Joseph Lister – introduced aseptic techniques reducing microbes in medical settings and preventing wound infections – Involved disinfection of hands using chemicals prior to surgery – Use of heat for sterilization
- 27. 27 Pathogens and Germ Theory of Disease • Many diseases are caused by the growth of microbes in the body and not by sins, bad character, or poverty, etc. • Two major contributors: Louis Pasteur and Robert Koch
- 28. 28 Louis Pasteur (1822-1895) • Showed microbes caused fermentation and spoilage • Disproved spontaneous generation of microorganisms • Developed pasteurization • Demonstrated what is now known as Germ Theory of Disease Insert figure 1.11
- 29. 29 Robert Koch (1843-1910) • Established Koch’s postulates - a sequence of experimental steps that verified the germ theory • Identified cause of anthrax, TB, and cholera • Developed pure culture methods Insert figure 1.12
- 30. 1.7 Taxonomy • Taxonomy: organizing, classifying, and naming living things – Formal system originated by Carl von Linné • Concerned with: – Classification – orderly arrangement of organisms into groups – Nomenclature – assigning names – Identification – determining and recording traits of organisms for placement into taxonomic schemes 30
- 31. 31 Levels of Classification • Domain - Archaea, Bacteria, & Eukarya • Kingdom • Phylum or Division • Class • Order • Family • Genus • Species
- 32. Figure 1.13 Sample taxonomy 32
- 33. 33 Assigning Specific Names • Binomial (scientific) nomenclature • Gives each microbe 2 names: – Genus - capitalized – species - lowercase • Both italicized or underlined – Staphylococcus aureus (S. aureus) • Inspiration for names is extremely varied and often imaginative
- 34. 34 The Origin and Evolution of Microorganisms • Phylogeny: natural relatedness between groups of organisms • Evolution – All new species originate from preexisting species – Closely related organism have similar features because they evolved from common ancestral forms • Evolution usually progresses toward greater complexity
- 35. 35 3 Domains • Bacteria - true bacteria • Archaea - odd bacteria that live in extreme environments, high salt, heat, etc. • Eukarya - have a nucleus and organelles
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