Chapter 1 - History of Microbiology PDF

PowerPoint® Lecture Presentations prepared by Mindy Miller-Kittrell, North Carolina State University CHAPTER 1...

PowerPoint® Lecture Presentations prepared by Mindy Miller-Kittrell, North Carolina State University CHAPTER 1 A Brief History of Microbiology © 2018 Pearson Education, Inc.  The Early Years of Microbiology What Does Life Really Look Like? Antoni van Leeuwenhoek Began making and using simple microscopes Often made a new microscope for each specimen Examined water and visualized tiny animals, fungi, algae, and single-celled protozoa; “animalcules” By end of 19th century, these organisms were called microorganisms. © 2018 Pearson Education, Inc.  Figure 1.1 Antoni van Leeuwenhoek. © 2018 Pearson Education, Inc.  Figure 1.2 Reproduction of Leeuwenhoek’s microscope. © 2018 Pearson Education, Inc.  Figure 1.3 The microbial world. © 2018 Pearson Education, Inc.  The Early Years of Microbiology How Can Microbes Be Classified? Carolus Linnaeus developed a taxonomic system for naming plants and animals and grouping similar organisms together. Leeuwenhoek’s microorganisms can be grouped into six categories: Bacteria Archaea Fungi Protozoa Algae Small multicellular animals © 2018 Pearson Education, Inc.  The Early Years of Microbiology How Can Microbes Be Classified? Bacteria and Archaea Unicellular and lack nuclei Much smaller than eukaryotes Found everywhere there is sufficient moisture; some isolated in extreme environments Reproduce asexually Bacterial cell walls contain peptidoglycan, though some lack cell walls. Archaeal cell walls are composed of polymers rather than peptidoglycan. © 2018 Pearson Education, Inc.  Figure 1.4 Cells of the bacterium Streptococcus (dark blue) and two human cheek cells. © 2018 Pearson Education, Inc.  The Early Years of Microbiology How Can Microbes Be Classified? Fungi Eukaryotic (have membrane-bound nucleus) Obtain food from other organisms Possess cell walls Include: Molds—multicellular; grow as long filaments; reproduce by sexual and asexual spores Yeasts—unicellular; reproduce asexually by budding; some produce sexual spores © 2018 Pearson Education, Inc.  Figure 1.5 Fungi. © 2018 Pearson Education, Inc.  The Early Years of Microbiology How Can Microbes Be Classified? Protozoa Single-celled eukaryotes Similar to animals in nutrient needs and cellular structure Live freely in water; some live in animal hosts Asexual (mostly) and sexual reproduction Most are capable of locomotion by: Pseudopods—cell extensions that flow in direction of travel Cilia—numerous short protrusions that propel organisms through its environment Flagella—extensions of a cell that are fewer, longer, and more whiplike than cilia © 2018 Pearson Education, Inc.  Figure 1.6 Locomotive structures of protozoa. © 2018 Pearson Education, Inc.  The Early Years of Microbiology How Can Microbes Be Classified? Algae Unicellular or multicellular Photosynthetic Simple reproductive structures Categorized on the basis of pigmentation and composition of cell wall © 2018 Pearson Education, Inc.  Figure 1.7 Algae. © 2018 Pearson Education, Inc.  The Early Years of Microbiology How Can Microbes Be Classified? Other organisms of importance to microbiologists Parasites Viruses © 2018 Pearson Education, Inc.  Figure 1.8 An immature stage of a parasitic worm in blood. © 2018 Pearson Education, Inc.  Figure 1.9 A colorized electron microscope image of viruses infecting a bacterium. © 2018 Pearson Education, Inc.  The Golden Age of Microbiology Scientists searched for answers to four questions: Is spontaneous generation of microbial life possible? What causes fermentation? What causes disease? How can we prevent infection and disease? © 2018 Pearson Education, Inc.  The Golden Age of Microbiology Does Microbial Life Spontaneously Generate? Some philosophers and scientists of the past thought living things arose from three processes: Asexual reproduction Sexual reproduction Nonliving matter Aristotle proposed spontaneous generation. Living things can arise from nonliving matter. © 2018 Pearson Education, Inc.  The Golden Age of Microbiology Does Microbial Life Spontaneously Generate? Redi’s experiments When decaying meat was kept isolated from flies, maggots never developed. Meat exposed to flies was soon infested. As a result, scientists began to doubt Aristotle’s theory. © 2018 Pearson Education, Inc.  Figure 1.10 Redi’s experiments. © 2018 Pearson Education, Inc.  The Golden Age of Microbiology Does Microbial Life Spontaneously Generate? Needham’s experiments Scientists agreed that large animals could not arise spontaneously, but believed microbes could. Needham’s experiments with beef gravy and infusions of plant material reinforced this idea. © 2018 Pearson Education, Inc.  The Golden Age of Microbiology Does Microbial Life Spontaneously Generate? Spallanzani’s experiments His experiments contradicted Needham’s findings. Concluded that: Needham failed to heat vials sufficiently to kill all microbes or had not sealed them tightly enough. Microorganisms exist in air and can contaminate experiments. Spontaneous generation of microorganisms does not occur; all living things arise from other living things. Critics said sealed vials did not allow enough air for organisms to survive and that prolonged heating destroyed the “life force.” © 2018 Pearson Education, Inc.  Figure 1.11 Louis Pasteur. © 2018 Pearson Education, Inc.  The Golden Age of Microbiology Does Microbial Life Spontaneously Generate? Pasteur’s experiments Performed experiments with “swan-necked” flasks When the flasks remained upright, no microbial growth appeared. When the flask was tilted, dust from the bend in the neck seeped back into the flask and made the infusion cloudy with microbes within a day. © 2018 Pearson Education, Inc.  Figure 1.12 Pasteur’s experiments with “swan-necked flasks.” © 2018 Pearson Education, Inc.  The Golden Age of Microbiology Does Microbial Life Spontaneously Generate? The scientific method Debate over spontaneous generation led in part to development of scientific method. Observation leads to question Question generates hypothesis Hypothesis is tested through experiment(s) Results prove or disprove hypothesis Accepted hypothesis leads to theory/law Disproved hypothesis is rejected or modified © 2018 Pearson Education, Inc.  Figure 1.13 The scientific method, which forms a framework for scientific research. © 2018 Pearson Education, Inc.  The Golden Age of Microbiology What Causes Fermentation? Spoiled wine threatened livelihood of many grape growers. Wine makers funded research of methods to promote production of alcohol and prevent spoilage during fermentation. The debate over the cause of fermentation reactions was also linked to the debate over spontaneous generation. © 2018 Pearson Education, Inc.  The Golden Age of Microbiology What Causes Fermentation? Pasteur’s experiments Some scientists believed air caused fermentation; others insisted that living organisms caused fermentation. Pasteur conducted a series of experiments that addressed the cause of fermentation. © 2018 Pearson Education, Inc.  Figure 1.14 How Pasteur applied the scientific method in investigating the nature of fermentation. © 2018 Pearson Education, Inc.  The Golden Age of Microbiology What Causes Fermentation? Pasteur’s experiments Led to the development of pasteurization Process of heating liquids just enough to kill most bacteria Began the field of industrial microbiology Intentional use of microbes for manufacturing products © 2018 Pearson Education, Inc.  Table 1.1 Some Industrial Uses of Microbes © 2018 Pearson Education, Inc.  The Golden Age of Microbiology What Causes Fermentation? Buchner’s experiments Demonstrated fermentation does not require living cells Showed enzymes promote chemical reactions Buchner’s work began the field of biochemistry. © 2018 Pearson Education, Inc.  The Golden Age of Microbiology What Causes Disease? Pasteur developed the germ theory of disease. Some diseases caused by specific germs called pathogens © 2018 Pearson Education, Inc.  Figure 1.15 Robert Koch. © 2018 Pearson Education, Inc.  The Golden Age of Microbiology What Causes Disease? Koch’s experiments Robert Koch studied causative agents of disease (etiology). Demonstrated a bacterium causes anthrax Examined colonies of microorganisms © 2018 Pearson Education, Inc.  The Golden Age of Microbiology What Causes Disease? Koch’s experiments Simple staining techniques First photomicrograph of bacteria First photograph of bacteria in diseased tissue Techniques for estimating bacterial number in a solution Use of steam to sterilize growth media Use of Petri dishes Laboratory techniques to transfer bacteria Bacteria as distinct species © 2018 Pearson Education, Inc.  Figure 1.16 Bacterial colonies on a solid surface (agar). © 2018 Pearson Education, Inc.  The Golden Age of Microbiology What Causes Disease? Koch’s postulates 1. Suspected causative agent must be found in every case of the disease and be absent from healthy hosts. 2. Agent must be isolated and grown outside the host. 3. When agent is introduced to a healthy, susceptible host, the host must get the disease. 4. Same agent must be found in the diseased experimental host. © 2018 Pearson Education, Inc.  Table 1.2 Other Notable Scientists of the “Golden Age of Microbiology” and the Agents of Disease They Discovered © 2018 Pearson Education, Inc.  The Golden Age of Microbiology What Causes Disease? Gram’s stain The most widely used staining technique One of the first steps to identify a bacterium © 2018 Pearson Education, Inc.  Figure 1.17 Results of Gram staining. © 2018 Pearson Education, Inc.  The Golden Age of Microbiology How Can We Prevent Infection and Disease? Ignaz Semmelweis and handwashing Joseph Lister’s antiseptic technique Florence Nightingale and nursing John Snow—infection control and epidemiology Edward Jenner’s vaccine—field of immunology Paul Ehrlich’s “magic bullets”—field of chemotherapy © 2018 Pearson Education, Inc.  Figure 1.18 Florence Nightingale. © 2018 Pearson Education, Inc.  Figure 1.19 Some of the many scientific disciplines and applications that arose from the pioneering work of scientists just before and around the time of the Golden Age of Microbiology. © 2018 Pearson Education, Inc.  Table 1.3 Fields of Microbiology (1 of 2) © 2018 Pearson Education, Inc.  Table 1.3 Fields of Microbiology (2 of 2) © 2018 Pearson Education, Inc.  The Modern Age of Microbiology What Are the Basic Chemical Reactions of Life? Biochemistry Began with Pasteur’s work on fermentation and Buchner’s discovery of enzymes in yeast extract Kluyver and van Niel—microbes used as model systems for biochemical reactions Practical applications: Design of herbicides and pesticides Diagnosis of illnesses and monitoring of patients’ responses to treatment Treatment of metabolic diseases Drug design © 2018 Pearson Education, Inc.  The Modern Age of Microbiology How Do Genes Work? Microbial genetics Molecular biology Recombinant DNA technology Gene therapy © 2018 Pearson Education, Inc.  The Modern Age of Microbiology How Do Genes Work? Microbial genetics Avery, MacLeod, and McCarty determined genes are contained in molecules of DNA. Beadle and Tatum established that a gene’s activity is related to protein function. Translation of genetic information into protein explained Rates and mechanisms of genetic mutation investigated Identify methods cells use to control genetic expression © 2018 Pearson Education, Inc.  The Modern Age of Microbiology How Do Genes Work? Molecular biology Explanation of cell function at the molecular level Pauling proposed that gene sequences could: Provide understanding of evolutionary relationships and processes Establish taxonomic categories to reflect these relationships Identify existence of microbes that have never been cultured Woese and Fox determined cells can be categorized as bacteria, archaea, or eukaryotes. Cat scratch disease caused by unculturable organism © 2018 Pearson Education, Inc.  The Modern Age of Microbiology How Do Genes Work? Recombinant DNA technology Genes in microbes, plants, and animals manipulated for practical applications Production of human blood-clotting factor by E. coli to aid hemophiliacs Gene therapy Inserting a missing gene or repairing a defective one in humans by inserting desired gene into host cells © 2018 Pearson Education, Inc.  The Modern Age of Microbiology What Role Do Microorganisms Play in the Environment? Bioremediation uses living bacteria, fungi, and algae to detoxify polluted environments. Recycling of chemicals such as carbon, nitrogen, and sulfur Causation of disease © 2018 Pearson Education, Inc.  The Modern Age of Microbiology How Do We Defend Against Disease? Serology The study of blood serum Von Behring and Kitasato—existence in the blood of chemicals and cells that fight infection Immunology The study of the body’s defenses against specific pathogens Chemotherapy Fleming discovered penicillin. Domagk discovered sulfa drugs. © 2018 Pearson Education, Inc.  Figure 1.20 The effects of penicillin on a bacterial “lawn” in a Petri dish. © 2018 Pearson Education, Inc.  Practice! Who finally debunked the theory of spontaneous generation? a. Francesco Redi b. John Needham c. Louis Pasteur d. Lazzaro Spallanzani  Practice! Whose postulates must be satisfied to identify a pathogen as the culprit of a disease? a. Edward Buchner b. Robert Koch c. John Snow d. Antoni van Leeuwenhoek  Practice! What did the Swan-necked flask experiment show? a. It proved that bacteria could spontaneously generate from non-living matter so long as oxygen was present b. It demonstrated that microorganisms are present in the air and can contaminate substances. c. It showed that air is not necessary for the growth of microorganisms. d. It demonstrated that enzymes can promote chemical reactions