1. Introduction to Microbiology David Lowrey, Ph.D.

2. This is you in two weeks

4. Learning Objectives Lesson 1.1: Scope of Microbiology
Describe the achievements of scientists in the early years of microbiology
Discuss the different types of microscopes and their use
Explain the theory of spontaneous generation
Discuss the germ theory of disease and its significance
Name and describe Koch’s postulates
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Elsevier items and derived items © 2011, 2006 by Saunders, an imprint of Elsevier Inc.

5. Learning Objectives Lesson 1.1: Scope of Microbiology (Cont.)
Discuss the origin and evolution of microorganisms
Describe the differences between prokaryotes and eukaryotes
Explain the role of taxonomy
Describe the different ways of microbial transmission
Name and briefly describe the different uses of microorganisms in everyday life
Copyright © 2016 by Elsevier Inc. All rights reserved.
Elsevier items and derived items © 2011, 2006 by Saunders, an imprint of Elsevier Inc.

6. What is Microbiology?
That field of biology that deals with organisms too small to see without magnification

7. Comparison of Cell Sizes
Microscopy allowed humans to magnify objects and microorganisms not detectable by the naked eye.
Technological advances have led to the improvement of microscopes, which became an essential investigative tool for biology in general and for the study of cells, tissues, and microorganisms.
Figure 1.1, A shows relative size comparisons of bacteria, eukaryotic cells, and viruses.
Figure 1.1, B shows a human cheek cell with resident bacteria, which are stained and appear as dark purple spheres or rods. A B
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8. Relative size of living things
Meter 1
Millimeter
Micrometer
Nanometer

9. Relative size of living things

10. Two types of cells Prokaryotic (no nucleus e. g
Two types of cells Prokaryotic (no nucleus e.g. bacteria) Eukayotic (has nucleus e.g. our cells)

11. Types of microorganisms

12. Figure 1.1

13. Bacteria Prokaryotic Peptidoglycan Reproduce by Binary fission
Chemo-, auto-, and
Phototrophs

14. Viruses Acellular Consist of DNA or RNA core
Core is surrounded by a protein coat
Coat may be enclosed in a lipid envelope
Viruses are replicated only when they are in a living host cell

15. Protozoa Eukaryotes Absorb or ingest organic chemicals
May be motile via pseudopods, cilia, or flagella

16. Helminths Eukaryotes Multicellular animals
Parasitic flatworms and roundworms are called helminths.
Microscopic stages in life cycles.

17. Fungi Eukaryotes Chitin cell walls Use organic chemicals for energy
Molds and mushrooms are multicellular, consisting of masses of mycelia, which are composed of filaments called hyphae
Yeasts are unicellular

18. Algae Eukaryotes Cellulose cell walls Use photosynthesis for energy
Produce molecular oxygen and organic compounds

19. Bioremediation Bacteria degrade organic matter in sewage
Bacteria degrade or detoxify pollutants such as oil and mercury

20. Biological Insecticides
Microbes that are pathogenic to insects are alternatives to chemical pesticides in preventing insect damage to agricultural crops and disease transmission
Bacillus thuringiensis infections are fatal in many insects but harmless to other animals, including humans, and to plants

21. Biotechnology
Biotechnology, the use of microbes to produce foods and chemicals, is centuries old

22. Designer Jeans: Made by Microbes?
Stone-washing: Trichoderma
Cotton: Gluconacetobacter
Debleaching: Mushroom peroxidase
Indigo: E. coli
Plastic: Bacterial polyhydroxyalkanoate
Applications of Microbiology, p. 3

23. History of Microbiology
Robert Hooke
1660s
Observed Cork
Primitive mcrosocope
Coined the term “cell”

24. History of microbiology
Anton van Leeuwnhoek
The “Father” of Microbiology
First to see microorganisms

25. Leeuwenhoek’s microscope
A simple microscope i.e. one lense
Magnification = 300X
Observed:
Microorganisms
Sperm from Animals
Protozoa
Helminths

26. Figure 1.2

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Robert Hooke (1635–1703)
English scientist
Improved the design and capability of the compound light microscope
Observed insects, sponges, protozoans, and more
Micrographia
Hooke published his observations with magnificent drawings in the book Micrographia.
He was requested by the Royal Society of London to confirm van Leeuwenhoek’s finding of animalcules and succeeded in doing so.
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Light Microscopes
Uses visible light and optical lenses
Either simple or compound
Ocular lens
Objective lens
Final magnification: Multiply the enlarging power of both the ocular and objective lenses
Example: ×10 times ×4 = ×40
A simple light microscope, such as van Leeuwenhoek’s, has a single magnifying lens and a visible light source and can magnify objects approximately 266 times (×266).
A compound light microscope also uses visible light, usually provided by an electric source, but uses multiple lenses for magnification.
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30. Light Microscopes (Cont.)
Dissection and stereomicroscopes
Low power: For observing whole objects
Bright-field microscopes
Background is lighter than observed specimen
Most specimens require fixing and staining for bright-field microscopy
Dissection microscopes and stereomicroscopes are designed for observing larger objects such as insects, worms, plants, or any objects that may have to be dissected for further observation. These microscopes provide three-dimensional images to determine surface structures and specific locations on a specimen.
Bright-field microscopes are most commonly used to observe sectioned and stained tissues, organs, and microorganisms.
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31. Louis Pasteur Fermentation Spontaneous generation Pasteurization
Germ Theory of disease
Immunization
Anthrax
Chicken cholera
rabies

32. The Debate over Generation of life
Spontaneous generation – living things arose from vital forces present in nonliving or decomposing matter
Meat left out generates maggots
Biogenesis – living things arise only from living things of the same kind

33. Pasteur’s Biogenesis experiment

34. Figure 1.3

35. The Germ Theory of Disease
1876: Robert Koch proved that a bacterium causes anthrax and provided the experimental steps, Koch’s postulates, to prove that a specific microbe causes a specific disease
Figure 1.4

36. A Fortunate Accident—Antibiotics
1928: Alexander Fleming discovered the first antibiotic
Fleming observed that Penicillium fungus made an antibiotic, penicillin, that killed S. aureus
1940s: Penicillin was tested clinically and mass produced
Figure 1.5

37. Vaccination
1796: Edward Jenner inoculated a person with cowpox virus, who was then protected from smallpox
Vaccination is derived from vacca, for cow
The protection is called immunity

38. Joseph Lister – introduced aseptic technique to surgery

39. Figure 1.5

40. Nobel Prizes for Microbiology Research
* The first Nobel Prize in Physiology or Medicine.
1901* von Behring Diphtheria antitoxin
1902 Ross Malaria transmission
1905 Koch TB bacterium
1908 Metchnikoff Phagocytes
1945 Fleming, Chain, Florey Penicillin
1952 Waksman Streptomycin
1969 Delbrück, Hershey, Luria Viral replication
1987 Tonegawa Antibody genetics
1997 Prusiner Prions
2005 Marshall & Warren H. pylori & ulcers

41. Whittaker’s
Five Kingdom classification Scheme

42. Woese and Fox – Classification by rRNA

43. Normal Microbiota on Human Tongue
Figure 1.7

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Taxonomy
The formal system of organizing, classifying, and naming living organisms
Domain, kingdom, phylum (division for bacteria), class, order, family, and genus, species, strain
Binomial (scientific) nomenclature: Established by Linnaeus
Escherichia coli
Taxonomy sorts organisms on the basis of mutual similarities into nonoverlapping groups called taxa.
The goal of taxonomy is classification, nomenclature, and identification for clarification and ease of reference.
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Kingdoms of Life
Figure 1.9 shows the present organization and hierarchy of the kingdoms of life. The bacteria Shigella sonnei has been traced from kingdom to the level of species to illustrate its place in the overall scheme.
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Taxonomy (Cont.)
Each organism has at least two names: Genus and species
Scientific names are italicized or underlined
Genus is capitalized, and species is in lower case
After the first use, scientific names may be abbreviated with the first letter of the genus
E. coli
The current system of taxonomy began with a Swedish botanist, Carolus Linnaeus. All categories in the Linnaeus system are taxa, which are hierarchic, starting with the species and genera, followed by successive taxa, each with a broader description than the preceding one. All names in the taxa are Latin or Latinized.
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47. Woese-Fox System: Three Domains
Bacteria
Archaea
Eukarya
Protists
Fungi
Plants
Animals
In 1990, Carl Woese and his colleagues introduced a three-domain system of taxonomy (archaea, bacteria, and eukarya) based on genetic rather than morphological similarities.
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Taxonomy (Cont.)
Bergey’s Manual of Systematic Bacteriology
The taxonomic resource for bacteria is Bergey’s Manual of Systematic Bacteriology, the second edition of which was published in five volumes. In addition to the number of keys for bacterial identification, newer versions of the manual also contain some molecular sequencing information for various bacterial groups.
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49. Microorganisms in Health and Disease
Microbial ecology
Often deals with biofilms
Interactions
Mutualism
Commensalism
Synergism
Parasitism
Microbial ecology is the study of the interrelationship between microbes and their environment. Microbes are everywhere in the environment and generally have an impact in maintaining ecosystems.
Ecological interactions between organisms in a community, including mutualism, commensalism, synergism, and parasitism, are classified according to the degree of benefit or harm they pose to one another. In mutualism both organisms benefit, in commensalism the waste product of a microbe provides useful nutrients for another organism, in synergism two organisms are dependent on each other to break down a nutrient that neither breaks down alone, and in parasitism one organism benefits and the other is harmed.
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50. Microorganisms in Health and Disease (Cont.)
Normal flora versus pathogens
Foodborne diseases
Organism/toxin contamination
Waterborne diseases
Organism contamination
Airborne diseases
Aerosols
The normal flora provides protection against pathogens by preventing attachment to the host tissue and by competing for the same nutrients. If the normal flora is successful, the pathogens cannot flourish or colonize and therefore are unable to reach sufficient numbers to cause infection.
Foodborne diseases result from consuming food that is contaminated with different pathogenic species of bacteria, viruses, parasites, or microbial toxins.
Waterborne disease is the general term used to describe diseases acquired from contaminated water supplies, resulting in four fifths of all illness in developing countries and a high infant death rate.
Airborne diseases are transmitted from infected people by coughing, sneezing, or talking. Pathogens are in small mucous saliva particles suspended as aerosols.
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Applied Microbiology
Food production
Yogurt, bread
Alcoholic beverages
Wine, beer
Treatment of water supplies
Indicator organisms
Pharmaceutical agents
Penicillin
Applied microbiology is the human use of microorganisms to improve certain aspects of life. Microbes are used in this capacity by the food, pharmaceutical, and agricultural industries and in forensics and other endeavors. Application of new technologies in genetic engineering has further increased the industrial use of microbes.
Many nonpathogenic microorganisms occur naturally in food.
Wine is produced by yeast fermentation of carbohydrates in freshly harvested grapes, peaches, berries, pears, and other fruits or plants (even dandelions). In beer production, barley or another grain is used as the source of fermentable carbohydrate.
The microbial content of drinking water should be constantly monitored to make sure the water is free of infectious agents.
Louis Pasteur observed the inhibition of microorganisms by products formed by other microbes. This phenomenon is called antibiosis. The discovery of the penicillin-producing mold Penicillium by Alexander Fleming in the 1920s started the successful search for other antibiotic-producing microorganisms.
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52. Applied Microbiology (Cont.)
Agriculture
Soil microbes, nitrogen cycle
Bioremediation
Petroleum-digesting bacteria
Energy
Fuel cells, ethanol, methane
Forensics
Medicine, criminal justice, epidemiology, bioterrorism
Agricultural microbiology focuses on the relationships between microbes and domesticated plants and animals.
Bioremediation is the process of using microorganisms to clean up toxic, hazardous, or unmanageable compounds by degrading them to harmless compounds. Some microbes performing these tasks have been genetically engineered to clean up specific wastes or pollutants.
By a process referred to as bioconversion, microorganisms can convert biomass such as organic matter and human, agricultural, and industrial waste into alternative fuels, including ethanol, methane, and hydrogen.
Microbial forensics is a relatively new field applied to solving bioterrorism cases, medical negligence, and outbreaks of foodborne diseases.
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