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Burton’s Microbiology for the Health Sciences Section I. Introduction to Microbiology

Burton’s Microbiology for the Health Sciences Section I. Introduction to Microbiology. Burton’s Microbiology for the Health Sciences Chapter 1. Microbiology — The Science. Chapter 1 Outline. Introduction What Is Microbiology? Why Study Microbiology? First Microorganisms on Earth

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Burton’s Microbiology for the Health Sciences Section I. Introduction to Microbiology

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  1. Burton’s Microbiologyfor the Health SciencesSection I. Introduction to Microbiology

  2. Burton’s Microbiology for the Health SciencesChapter 1. Microbiology—The Science

  3. Chapter 1 Outline • Introduction • What Is Microbiology? • Why Study Microbiology? • First Microorganisms on Earth • Earliest Known Infectious Diseases • Pioneers in the Science of Microbiology • Careers in Microbiology

  4. What Is Microbiology? • Biology is the study of living organisms. • Microbiology is an advanced biology course. • Microbiology is the study of microbes, which are extremely small (microscopic) living organisms and certain nonliving entities. • Living microbes are known as cellular microbes or microorganisms; examples include bacteria, archaea, some algae, protozoa, and some fungi. • Nonliving microbes are known as acellular microbes or infectious particles; examples include viroids, prions, and viruses. • Microbes are ubiquitous (i.e., they are found virtually everywhere).

  5. Acellular and Cellular Microbes

  6. What Is Microbiology?—(cont.) • The microbes that cause disease are sometimes referred to as “germs.” • The scientific term for disease-causing microbes is pathogens. • Microbes that do not cause disease are called nonpathogens; the vast majority of microbes are nonpathogens.

  7. What Is Microbiology?—(cont.) • Microbes that live on and in our bodies are referred to as our indigenous microbiota. • Some members of our indigenous microbiota are opportunistic pathogens. • Opportunistic pathogens are microbes that can cause disease, but usually do not; they can be thought of as microbes that are awaiting the opportunity to cause disease. • Pathogens cause two categories of diseases: infectious diseases and microbial intoxications.

  8. Categories of Diseases Caused by Pathogens

  9. Why Study Microbiology? • Microbes play significant roles in our lives; they are essential for life on this planet. • Photosynthetic algae and bacteria (such as cyanobacteria) produce much of the oxygen in our atmosphere. • Microorganisms are involved in the decomposition of dead organisms and waste products. • Saprophytes are organisms that live on dead and/or decaying organic matter. • The use of microbes to clean up toxic wastes and other industrial waste products is known as bioremediation.

  10. Microbes as Saprophytes

  11. Why Study Microbiology?—(cont.) • Many microbes play essential roles in various elemental cycles, such as the carbon, nitrogen, oxygen, sulfur, and phosphorus cycles. • Algae and bacteria serve as food for tiny animals; they are important links in food chains. • Microbes that live in the intestinal tracts of animals aid in the digestion of food and produce beneficial substances. • For many years, microorganisms have been used as “cell models”; the more the scientists learned about microbial cells, the more they learned about cells in general.

  12. Microbes and Nitrogen Fixation

  13. Why Study Microbiology?—(cont.) • Microbes are used in many industries, such as food, beverage, chemical, and antibiotic industries and in genetic engineering. • In genetic engineering, a gene(s) from one organism is inserted into a bacterial or yeast cell; the cell that receives the new gene(s) is then capable of producing the gene product(s) coded for by the new gene(s). • The use of living organisms or their derivatives to make or modify useful products or processes is called biotechnology.

  14. Microbes and the Food Chain

  15. First Microorganisms on Earth • Fossils of primitive microorganisms date back about 3.5 billion years. • Candidates for the first microorganisms on Earth are archaea and cyanobacteria. • Infectious diseases of humans and animals have existed for as long as humans and animals have inhabited the planet. • Earliest known account of pestilence occurred in Egypt in about 3180 BC.

  16. Pioneers in the Science of Microbiology Anton van Leeuwenhoek (1632–1723) • “Father of Microbiology” • Not a trained scientist! • Made many simple single-lens microscopes • Observed “animalcules” (bacteria and protozoa)

  17. Pioneers in the Science of Microbiology— (cont.) Louis Pasteur (1822–1895) • French chemist who made numerous contributions to microbiology • Investigated different fermentation products • Developed the pasteurization process • Discovered life forms that could exist without oxygen (anaerobes) • Developed several vaccines, including rabies and anthrax vaccines

  18. Pioneers in the Science of Microbiology—(cont.) Robert Koch (1843–1910) • German physician who made numerous contributions to microbiology • Made significant contributions to the germ theory of disease • Discovered that Bacillus anthracis produced spores • Developed methods of fixing and staining bacteria • Developed methods to cultivate bacteria

  19. Koch’s Postulates • A particular microbe must be found in all cases of the disease and must not be present in healthy animals or humans. • The microbe must be isolated from the diseased animal or human and grown in pure culture in the laboratory. • The same disease must be produced when microbes from the pure culture are inoculated into healthy susceptible laboratory animals. • The same microbe must be recovered from the experimentally infected animals and grown again in pure culture.

  20. Koch’s Postulates—(cont.)

  21. Koch’s Postulates—(cont.) • If an organism fulfills Koch’s Postulates, it has been proven to be the cause of that particular infectious disease. • Koch’s Postulates helped prove the germ theory of disease. • Koch gave a tremendous boost to the development of microbiology by stressing laboratory culture and identification of microorganisms. • Circumstances do exist in which Koch’s Postulates cannot be fulfilled.

  22. Careers in Microbiology • A microbiologist is a scientist who studies microbes. • There are many career fields within the science of microbiology (e.g., bacteriology, phycology, protozoology, mycology, parasitology, and virology). • Medical microbiology • Involves the study of pathogens, the disease they cause, and the body’s defenses against disease • Concerned with epidemiology, transmission of pathogens, disease-prevention measures, aseptic techniques, treatment of infectious diseases, immunology, and production of vaccines

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