Chapter 1

1. Chapter 1 A Brief History of Microbiology

2. The Early Years of Microbiology What Does Life Really Look Like? Antoni van Leeuwenhoek (Dutch) 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 © 2012 Pearson Education Inc.

3. Figure 1.1 Antoni van Leeuwenhoek

4. Specimen holder Lens Figure 1.2 Reproduction of Leeuwenhoek’s microscope

5. Figure 1.3 The microbial world

6. The Early Years of Microbiology How Can Microbes Be Classified? Carolus Linnaeus developed taxonomic system for grouping similar organisms together Leeuwenhoek’s microorganisms grouped into six categories: Bacteria Archaea Fungi Protozoa Algae Small multicellular animals © 2012 Pearson Education Inc.

7. The Early Years of Microbiology Bacteria and Archaea Unicellular and lack nuclei Much smaller than eukaryotes Found everywhere there is sufficient moisture Reproduce asexually Two kinds Bacteria – cell walls contain peptidoglycan Archaea – cell walls composed of polymers other than peptidoglycan © 2012 Pearson Education Inc.

8. Nucleus ofeukaryotic cheek cell Prokaryoticbacterial cells Figure 1.4 Cells of the bacterium Streptococcus

9. The Early Years of Microbiology 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 by budding or sexual spores © 2012 Pearson Education Inc.

10. Figure 1.5 Fungi-overview

11. The Early Years of Microbiology Protozoa Single-celled eukaryotes Similar to animals in nutrient needs and cellular structure Live freely in water; some live in animal hosts Asexual (most) and sexual reproduction Most are capable of locomotion by Pseudopodia Cilia Flagella © 2012 Pearson Education Inc.

12. Figure 1.6 Locomotive structures of protozoa-overview

13. The Early Years of Microbiology Algae Unicellular or multicellular Photosynthetic Simple reproductive structures Categorized on the basis of pigmentation, storage products, and composition of cell wall © 2012 Pearson Education Inc.

14. Figure 1.7 Algae-overview

15. Red blood cell Figure 1.8 An immature stage of a parasitic worm in blood

16. Virus Figure 1.9 Viruses infecting a bacterium Bacterium Virusesassemblinginside cell

17. 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? © 2012 Pearson Education Inc.

18. The Golden Age of Microbiology Some thought living things arose from three processes Asexual reproduction Sexual reproduction Nonliving matter Aristotle proposed spontaneous generation Living things can arise from nonliving matter © 2012 Pearson Education Inc.

19. The Golden Age of Microbiology 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 © 2012 Pearson Education Inc.

20. Figure 1.10 Redi’s experiments Flask coveredwith gauze Flask sealed Flask unsealed

21. The Golden Age of Microbiology Needham’s Experiments Scientists thought microbes, but not animals, could arise spontaneously Needham’s experiments reinforced this idea © 2012 Pearson Education Inc.

22. The Golden Age of Microbiology Spallanzani’s Experiments Conclusions Needham failed to heat vials sufficiently to kill all microbes or had not sealed vials tightly enough Microorganisms exist in air and can contaminate experiments Spontaneous generation does not occur Critics argued against experiments Sealed vials did not allow enough air for organisms to survive Prolonged heating destroyed “life force” © 2012 Pearson Education Inc.

23. Figure 1.11 Louis Pasteur

24. The Golden Age of Microbiology Pasteur’s Experiments When the “swan-necked” 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 © 2012 Pearson Education Inc.

25. Figure 1.12 Pasteur’s experiments with “swan-necked” flasks Steam escapesfrom open endof flask. Dust fromair settlesin bend. Air moves inand out of flask. Months Infusion remainssterile indefinitely. Infusion sits;no microbes appear. Infusionis heated.

26. The Golden Age of Microbiology The Scientific Method Spontaneous generation debate led in part to 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 Reject or modify hypothesis © 2012 Pearson Education Inc.

27. Figure 1.13 The scientific method Observations Theoryor law Experimentaldata supporthypothesis Accepthypothesis Repeat Question Experiment,includingcontrol groups Rejecthypothesis Hypothesis Observations Experimentaldata do notsupporthypothesis Modifyhypothesis Modifiedhypothesis

28. The Golden Age of Microbiology What Causes Fermentation? Spoiled wine threatened livelihood of vintners Some believed air caused fermentation Others insisted living organisms caused fermentation Vintners funded research to prevent spoilage during fermentation This debate also linked to debate over spontaneous generation © 2012 Pearson Education Inc.

29. Spontaneousfermentationoccurs. I. Air fermentsgrape juice. II. Bacteria fermentgrape juiceinto alcohol. III. Yeasts fermentgrape juiceinto alcohol. IV. Figure 1.14 Pasteur's application of the scientific method Observation: Microscopic analysisshows juice containsyeasts and bacteria. Fermentinggrape juice Experiment Conclusion Hypothesis Observation Day 1: Flasks of grapejuice are heated sufficientlyto kill all microbes. Day 2 Reject hypothesis I. No fermentation;juice remainsfree of microbes Flask is sealed. No fermentation;juice remainsfree of microbes Reject hypothesis II. Flask remainsopen to airvia curved neck. Bacteria reproduce;acids are produced. Modify hypothesis III; bacteria fermentgrape juice intoacids. Juice in flask is inoculated withbacteria and sealed. Yeasts reproduce;alcohol is produced. Accept hypothesis IV; yeasts fermentgrape juice intoalcohol. Juice in flask is inoculated withyeast and sealed.

30. Table 1.1 Some Industrial Uses of Microbes

31. The Golden Age of Microbiology What Causes Disease? Pasteur developed germ theory of disease Robert Koch studied causative agents of disease Anthrax Examined colonies of microorganisms © 2012 Pearson Education Inc.

32. Figure 1.15 Robert Koch

33. The Golden Age of Microbiology Koch’s Contributions Simple staining techniques First photomicrograph of bacteria First photomicrograph of bacteria in diseased tissue Techniques for estimating CFU/ml Use of steam to sterilize media Use of Petri dishes Techniques to transfer bacteria Bacteria as distinct species © 2012 Pearson Education Inc.

34. Figure 1.16 Bacterial colonies on agar Bacterium 6 Bacterium 7 Bacterium 8 Bacterium 5 Bacterium 9 Bacterium 4 Bacterium 3 Bacterium 10 Bacterium 2 Bacterium 11 Bacterium 1 Bacterium 12

35. The Golden Age of Microbiology Koch’s Postulates Suspected causative agent must be found in every case of the disease and be absent from healthy hosts Agent must be isolated and grown outside the host When agent is introduced into a healthy, susceptible host, the host must get the disease Same agent must be found in the diseased experimental host © 2012 Pearson Education Inc.

36. Table 1.2 Other Notable Scientists of the “Golden Age of Microbiology” and the Agents of Disease They Discovered

37. The Golden Age of Microbiology Gram’s Stain Danish scientist Hans Christian Gram developed more important staining technique than Koch’s in 1884 Involves the applications of a series of dyes Some microbes are left purple, now labeled Gram-positive Other microbes are left pink, now labeled Gram-negative Gram procedure used to separate into two groups © 2012 Pearson Education Inc.

38. Gram-negative Gram-positive Figure 1.17 Results of Gram staining

39. The Golden Age of Microbiology How Can We Prevent Infection and Disease? Semmelweis and handwashing Lister’s antiseptic technique Nightingale and nursing Snow – infection control and epidemiology Jenner’s vaccine – field of immunology Ehrlich’s “magic bullets” – field of chemotherapy © 2012 Pearson Education Inc.

40. Figure 1.18 Florence Nightingale

41. BIOLOGISTS MODERN DISCIPLINES Bacteriology (bacteria)Protozoology (protozoa)Mycology (fungi)Parasitology (protozoa andanimals)Phycology (algae) Pre-1857 Leeuwenhoek Figure 1.19 Some scientific disciplines and applications Taxonomy Linnaeus SemmelweissSnow Infection controlEpidemiology The Golden Age ofMicrobiology (1857–1907) Industrial microbiology Pasteur Food and beverage technology Pasteurization Microbial metabolism GeneticsGenetic engineering Buchner Koch’s postulates Etiology Koch Virology Ivanowski BeijerinckWinogradsky Environmental microbiologyEcological microbiology Microbial morphology Gram ListerNightingale Antiseptic medical techniquesHospital microbiology Jennervon BehringKitasato SerologyImmunology Ehrlich Chemotherapy Fleming Pharmaceutical microbiology

42. Table 1.3 Fields of Microbiology

43. The Modern Age of Microbiology What Are the Basic Chemical Reactions of Life? Biochemistry Began with Pasteur’s and Buchner’s works Microbes used as model systems for biochemical reactions Practical applications Design of herbicides and pesticides Diagnosis of illness and monitoring responses to treatment Treatment of metabolic diseases Drug design © 2012 Pearson Education Inc.

44. The Modern Age of Microbiology How Do Genes Work? Microbial genetics Molecular biology Recombinant DNA technology Gene therapy © 2012 Pearson Education Inc.

45. The Modern Age of Microbiology Microbial Genetics Avery, MacLeod, and McCarty: genes are contained in molecules of DNA Beadle and Tatum: a gene’s activity is related to protein function Translation of genetic information into protein explained Rates and mechanisms of genetic mutation investigated Control of genetic expression by cells described © 2012 Pearson Education Inc.

46. The Modern Age of Microbiology Molecular Biology Explanation of cell function at the molecular level Pauling proposed that gene sequences could Provide understanding of evolutionary relationships/processes Establish taxonomic categories Identify microbes that have never been cultured Woese determined cells belong to bacteria, archaea, or eukaryotes Cat scratch disease caused by unculturable organism © 2012 Pearson Education Inc.

47. The Modern Age of Microbiology 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 © 2012 Pearson Education Inc.

48. The Modern Age of Microbiology What Roles 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 © 2012 Pearson Education Inc.

49. The Modern Age of Microbiology How Do We Defend Against Disease? Serology The study of blood serum Blood contains chemicals and cells that fight infection Immunology The study of the body’s defense against specific pathogens Chemotherapy Fleming discovered penicillin Domagk discovered sulfa drugs © 2012 Pearson Education Inc.

50. Figure 1.20 Effects of penicillin on a bacterial “lawn” in a petri dish Fungus colony(Penicillium) Zone of inhibition Bacterial colonies(Staphylococcus)