1. The Microbial World and You1
The Microbial World and You

3. Microbes in Our Lives
Learning Objective 1-1 List several ways in which microbes affect our lives.

4. Microbes in Our Lives
Microorganisms are organisms that are too small to be seen with the unaided eye
Microbes include bacteria, fungi, protozoa, microscopic algae, and viruses

5. Microbes in Our Lives A few are pathogenic (disease-producing)
Decompose organic waste
Generate oxygen by photosynthesis
Produce chemical products such as ethanol, acetone, and vitamins
Produce fermented foods such as vinegar, cheese, and bread
Produce products used in manufacturing (e.g., cellulase) and disease treatment (e.g., insulin)

6. Designer Jeans: Made by Microbes?
Denim fading: Trichoderma
Cotton production: Gluconacetobacter
Bleaching: mushroom peroxidase
Indigo: Escherichia coli
Plastic: bacterial polyhydroxyalkanoate

7. Applications of Microbiology 1.1

8. Applications of Microbiology 1.2

9. Microbes in Our Lives Knowledge of microorganisms allows humans to
Prevent food spoilage
Prevent disease
Understand causes and transmission of disease to prevent epidemics

10. Check Your Understanding
Describe some of the destructive and beneficial actions of microbes. 1-1

11. Naming and Classifying Microorganisms
Learning Objectives 1-2 Recognize the system of scientific nomenclature that uses two names: a genus and a specific epithet. 1-3 Differentiate the major characteristics of each group of microorganisms. 1-4 List the three domains.

12. Naming and Classifying Microorganisms
Carolus Linnaeus established the system of scientific nomenclature in 1735
Each organism has two names: the genus and the specific epithet

13. Nomenclature Scientific names Are italicized or underlined
The genus is capitalized; the specific epithet is lowercase
Are "Latinized" and used worldwide
May be descriptive or honor a scientist

14. Nomenclature Escherichia coli Honors the discoverer, Theodor Escherich
Describes the bacterium's habitat—the large intestine, or colon

15. Nomenclature Staphylococcus aureus
Describes the clustered (staphylo-) spherical (coccus) cells
Describes the gold-colored (aureus) colonies

16. Nomenclature
After the first use, scientific names may be abbreviated with the first letter of the genus and the specific epithet:
Escherichia coli and Staphylococcus aureus are found in the human body
E. coli is found in the large intestine, and S. aureus is on skin

17. Check Your Understanding
Distinguish a genus from a specific epithet. 1-2

18. Types of Microorganisms
Bacteria
Archaea
Fungi
Protozoa
Algae
Viruses
Multicellular Animal Parasites

19. Figure 1.1 Types of microorganisms.
Bacteria
Sporangia
Food
particle
Pseudopod
CD4 + T cell
HIVs

20. Bacteria Prokaryotes Single-celled Peptidoglycan cell walls
”Prenucleus"
Single-celled
Peptidoglycan cell walls
Divide via binary fission
Derive nutrition from organic or inorganic chemicals or photosynthesis

21. Figure 1.1a Types of microorganisms.
Bacteria

22. Archaea Prokaryotes Lack peptidoglycan cell walls
Often live in extreme environments
Include:
Methanogens
Extreme halophiles
Extreme thermophiles

23. Fungi Eukaryotes Chitin cell walls Absorb organic chemicals for energy
Distinct nucleus
Chitin cell walls
Absorb organic chemicals for energy
Yeasts are unicellular
Molds and mushrooms are multicellular
Molds consist of masses of mycelia, which are composed of filaments called hyphae

24. Figure 1.1b Types of microorganisms.
Sporangia

25. Protozoa Eukaryotes Absorb or ingest organic chemicals
May be motile via pseudopods, cilia, or flagella
Free-living or parasitic (derive nutrients from a living host)

26. Figure 1.1c Types of microorganisms.
Food
particle
Pseudopod

27. Algae Eukaryotes Cellulose cell walls
Found in freshwater, saltwater, and soil
Use photosynthesis for energy
Produce oxygen and carbohydrates

28. Figure 1.1d Types of microorganisms.

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

30. Figure 1.1e Types of microorganisms.
CD4 + T cell
HIVs

31. Multicellular Animal Parasites
Eukaryotes
Multicellular animals
Not strictly microorganisms
Parasitic flatworms and roundworms are called helminths
Some microscopic stages in their life cycles

32. Check Your Understanding
Which groups of microbes are prokaryotes? Which are eukaryotes? 1-3

33. Classification of Microorganisms
Developed by Carl Woese
Three domains based on cellular organization
Bacteria
Archaea
Eukarya
Protists
Fungi
Plants
Animals

34. Figure 10.1 Three-Domain System.

35. Check Your Understanding
What are the three domains? 1-4

36. A Brief History of Microbiology
Learning Objectives 1-5 Explain the importance of observations made by Hooke and van Leeuwenhoek. 1-6 Compare spontaneous generation and biogenesis. 1-7 Identify the contributions to microbiology made by Needham, Spallanzani, Virchow, and Pasteur.

37. The First Observations
1665: Robert Hooke reported that living things are composed of little boxes, or "cells"
Marked the beginning of cell theory: All living things are composed of cells
The first microbes were observed from 1623–1673 by Anton van Leeuwenhoek
"Animalcules" viewed through magnifying lenses

38. Figure 1.2b Anton van Leeuwenhoek's microscopic observations.
Lens
Location of
specimen on pin
Specimen-
positioning screw
Focusing control
Stage-
positioning screw
Microscope replica

39. Check Your Understanding
What is the cell theory? 1-5

40. The Debate over Spontaneous Generation
Spontaneous generation: the hypothesis that life arises from nonliving matter; a "vital force" is necessary for life
Biogenesis: the hypothesis that living cells arise only from preexisting living cells

41. The Debate over Spontaneous Generation
1668: Francesco Redi filled jars with decaying meat
Conditions
Results
Jars covered with fine net
No maggots
Open jars
Maggots appeared
Sealed jars
From where did the maggots come?
What was the purpose of the sealed jars?
Spontaneous generation or biogenesis?

42. The Debate over Spontaneous Generation
1745: John Needham put boiled nutrient broth into covered flasks
Conditions
Results
Nutrient broth heated, then placed in covered flask
Microbial growth
From where did the microbes come?
Spontaneous generation or biogenesis?

43. The Debate over Spontaneous Generation
1765: Lazzaro Spallanzani boiled nutrient solutions in sealed flasks
Conditions
Results
Nutrient broth placed in flask, sealed, then heated
No microbial growth
Spontaneous generation or biogenesis?

44. The Theory of Biogenesis
1858: Rudolf Virchow said cells arise from preexisting cells

45. The Theory of Biogenesis
1861: Louis Pasteur demonstrated that microorganisms are present in the air
Conditions
Results
Nutrient broth placed in flask, heated, NOT sealed
Microbial growth
Nutrient broth placed in flask, heated, then immediately sealed
No microbial growth
Spontaneous generation or biogenesis?

46. The Theory of Biogenesis
Pasteur also used S-shaped flasks
Keep microbes out but let air in
Broth in flasks showed no signs of life
Neck of flask traps microbes
Microorganisms originate in air or fluids, not mystical forces

47. Figure 1.3 Disproving the Theory of Spontaneous Generation.

48. Check Your Understanding
What evidence supported spontaneous generation? 1-6
How was spontaneous generation disproved? 1-7

49. A Brief History of Microbiology
Learning Objectives 1-8 Explain how Pasteur's work influenced Lister and Koch. 1-9 Identify the importance of Koch's postulates Identify the importance of Jenner's work Identify the contributions to microbiology made by Ehrlich and Fleming.

50. The Golden Age of Microbiology
1857–1914
Beginning with Pasteur's work, discoveries included the relationship between microbes and disease, immunity, and antimicrobial drugs

51. The Golden Age of Microbiology
Pasteur showed that microbes are responsible for fermentation
Fermentation is the microbial conversion of sugar to alcohol in the absence of air
Microbial growth is also responsible for spoilage of food and beverages
Bacteria that use air spoil wine by turning it to vinegar (acetic acid)

52. The Golden Age of Microbiology
Pasteur demonstrated that these spoilage bacteria could be killed by heat that was not hot enough to evaporate the alcohol in wine
Pasteurization is the application of a high heat for a short time to kill harmful bacteria in beverages

53. Figure 1.4 Milestones in the Golden Age of Microbiology (1 of 3).

54. The Germ Theory of Disease
1835: Agostino Bassi showed that a silkworm disease was caused by a fungus
1865: Pasteur showed that another silkworm disease was caused by a protozoan
1840s: Ignaz Semmelweis advocated handwashing to prevent transmission of puerperal fever from one obstetrical patient to another

55. The Germ Theory of Disease
1860s: Applying Pasteur's work showing that microbes are in the air, can spoil food, and cause animal diseases, Joseph Lister used a chemical antiseptic (phenol) to prevent surgical wound infections

56. Figure 1.4 Milestones in the Golden Age of Microbiology (2 of 3).

57. The Germ Theory of Disease
1876: Robert Koch discovered that a bacterium causes anthrax and provided the experimental steps, Koch's postulates, to demonstrate that a specific microbe causes a specific disease

58. Figure 1.4 Milestones in the Golden Age of Microbiology (3 of 3).

59. Vaccination
1796: Edward Jenner inoculated a person with cowpox virus, who was then immune from smallpox
Vaccination is derived from the Latin word vacca, meaning cow
The protection is called immunity

60. Check Your Understanding
Summarize in your own words the germ theory of disease. 1-8
What is the importance of Koch's postulates? 1-9
What is the significance of Jenner's discovery? 1-10

61. The Birth of Modern Chemotherapy: Dreams of a "Magic Bullet"
Treatment of disease with chemicals is called chemotherapy
Chemotherapeutic agents used to treat infectious disease can be synthetic drugs or antibiotics
Antibiotics are chemicals produced by bacteria and fungi that inhibit or kill other microbes

62. The First Synthetic Drugs
Quinine from tree bark was long used to treat malaria
Paul Ehrlich speculated about a "magic bullet" that could destroy a pathogen without harming the host
1910: Ehrlich developed a synthetic arsenic drug, salvarsan, to treat syphilis
1930s: Sulfonamides were synthesized

63. A Fortunate Accident—Antibiotics
1928: Alexander Fleming discovered the first antibiotic (by accident)
Fleming observed that Penicillium fungus made an antibiotic, penicillin, that killed S. aureus
1940s: Penicillin was tested clinically and mass-produced

64. Figure 1.5 The discovery of penicillin.
Normal
bacterial
colony
Area of
inhibited
bacterial
growth
Penicillium
colony

65. Check Your Understanding
What was Ehrlich's "magic bullet"? 1-11

66. Modern Developments in Microbiology
Learning Objectives 1-12 Define bacteriology, mycology, parasitology, immunology, and virology Explain the importance of microbial genetics and molecular biology.

67. Bacteriology, Mycology, and Parasitology
Bacteriology is the study of bacteria
Mycology is the study of fungi
Parasitology is the study of protozoa and parasitic worms

68. Figure 1.6 Parasitology: the study of protozoa and parasitic worms.

69. Immunology Immunology is the study of immunity
Vaccines and interferons are used to prevent and cure viral diseases
A major advance in immunology occurred in 1933 when Rebecca Lancefield classified streptococci based on their cell wall components

70. Figure 1.7 Rebecca Lancefield (1895–1981), who discovered differences in the chemical composition of a polysaccharide in the cell walls of many pathogenic streptococci.

71. Virology Virology is the study of viruses
Dmitri Iwanowski in 1892 and Wendell Stanley in 1935 discovered the cause of mosaic disease of tobacco as a virus
Electron microscopes have made it possible to study the structure of viruses in detail

72. Recombinant DNA Technology
Microbial genetics: the study of how microbes inherit traits
Molecular biology: the study of how DNA directs protein synthesis
Genomics: the study of an organism's genes; has provided new tools for classifying microorganisms
Recombinant DNA: DNA made from two different sources
In the 1960s, Paul Berg inserted animal DNA into bacterial DNA, and the bacteria produced an animal protein

73. Recombinant DNA Technology
1941: George Beadle and Edward Tatum showed that genes encode a cell's enzymes
1944: Oswald Avery, Colin MacLeod, and Maclyn McCarty showed that DNA is the hereditary material
1953: James Watson and Francis Crick proposed a model of DNA structure
1961: François Jacob and Jacques Monod discovered the role of mRNA in protein synthesis

74. Figure 1.4 Milestones in the Golden Age of Microbiology.

75. Check Your Understanding
Define bacteriology, mycology, parasitology, immunology, and virology
Differentiate microbial genetics from molecular biology

76. Microbes and Human Welfare
Learning Objectives 1-14 List at least four beneficial activities of microorganisms Name two examples of biotechnology that use recombinant DNA technology and two examples that do not.

77. Recycling Vital Elements
Microbial ecology is the study of the relationship between microorganisms and their environment
Bacteria convert carbon, oxygen, nitrogen, sulfur, and phosphorus into forms used by plants and animals

78. Bioremediation: Using Microbes to Clean Up Pollutants
Bacteria degrade organic matter in sewage
Bacteria degrade or detoxify pollutants such as oil and mercury

79. Figure 27.8 Composting municipal wastes.

80. Insect Pest Control by Microorganisms
Microbes that are pathogenic to insects are alternatives to chemical pesticides
Prevent insect damage to agricultural crops and disease transmission
Bacillus thuringiensis infections are fatal in many insects but harmless to animals and plants

81. Bacillus thuringiensis. The diamond-shaped
Figure Bacillus.
Endospore
Collapsed
B. thuringiensis
Toxic crystal
Bacillus thuringiensis. The diamond-shaped
crystals shown next to the endospore are toxic
to insects that ingest them. This electron
micrograph was made using the technique of
shadow casting.

82. Modern Biotechnology and Recombinant DNA Technology
Biotechnology is the use of microbes for practical applications, such as producing foods and chemicals
Recombinant DNA technology enables bacteria and fungi to produce a variety of proteins, vaccines, and enzymes
Missing or defective genes in human cells can be replaced in gene therapy
Genetically modified bacteria are used to protect crops from insects and from freezing

83. Check Your Understanding
Name two beneficial uses of bacteria
Differentiate biotechnology from recombinant DNA technology

84. Microbes and Human Disease
Learning Objectives 1-16 Define normal microbiota and resistance Define biofilm Define emerging infectious disease.

85. Normal Microbiota
Bacteria were once classified as plants, giving rise to the term flora for microbes
This term has been replaced by microbiota
Microbes normally present in and on the human body are called normal microbiota

86. Figure 1.8 Several types of bacteria found as part of the normal microbiota on the surface of the human tongue.

87. Normal Microbiota Normal microbiota prevent growth of pathogens
Normal microbiota produce growth factors such as vitamins B and K
Resistance is the ability of the body to ward off disease
Resistance factors include skin, stomach acid, and antimicrobial chemicals

88. Biofilms Microbes attach to solid surfaces and grow into masses
They will grow on rocks, pipes, teeth, and medical implants
Biofilms can cause infections and are often resistant to antibiotics

89. Figure 1.9 Biofilm on a catheter.
Staphylococcus

90. Emerging Infectious Diseases
When a pathogen invades a host and overcomes the host's resistance, disease results
Emerging infectious diseases (EIDs): new diseases and diseases increasing in incidence

91. Emerging Infectious Diseases
Middle East respiratory syndrome (MERS)
Caused by Middle East respiratory syndrome coronavirus (MERS-CoV)
Common to SARS
Severe acute respiratory syndrome
100 deaths in the Middle East from 2012 to 2014

92. Emerging Infectious Diseases
Avian influenza A (H5N1)
Influenza A virus
Primarily in waterfowl and poultry
Sustained human-to-human transmission has not yet occurred

93. Figure 13.3b Morphology of an enveloped helical virus.
Spikes

94. Emerging Infectious Diseases
Methicillin-resistant Staphylococcus aureus (MRSA)
1950s: Penicillin resistance developed
1980s: Methicillin resistance
1990s: MRSA resistance to vancomycin reported
VISA: vancomycin-intermediate S. aureus
VRSA: vancomycin-resistant S. aureus

95. Emerging Infectious Diseases
West Nile encephalitis (WNE)
Caused by West Nile virus
First diagnosed in the West Nile region of Uganda in 1937
Appeared in New York City in 1999
In nonmigratory birds in 48 states
Transmitted between birds and to horses and humans by mosquitoes

96. Diseases in Focus 22.2 (1 of 3)

97. Emerging Infectious Diseases
Bovine spongiform encephalopathy
Caused by a prion
An infectious protein that also causes Creutzfeldt-Jakob disease (CJD)
New variant of CJD in humans is related to cattle that have been given feed made from prion-infected sheep

98. Figure 22.18b Spongiform encephalopathies.
Holes

99. Emerging Infectious Diseases
E. coli O157:H7
Toxin-producing strain of E. coli
First seen in 1982; causes bloody diarrhea
Leading cause of diarrhea worldwide

100. Figure 25. 11 Pedestal formation by Enterohemorrhagic E
Figure Pedestal formation by Enterohemorrhagic E. coli (EHEC) O157:H7.

101. Emerging Infectious Diseases
Ebola hemorrhagic fever (EHF)
Ebola virus
Causes fever, hemorrhaging, and blood clotting
Transmitted via contact with infected blood or body fluids
First identified near Ebola River, Congo
2014 outbreak in Guinea; hundreds killed

102. Figure 23.21 Ebola hemorrhagic virus.

103. Emerging Infectious Diseases
Cryptosporidiosis
Cryptosporidium protozoa
First reported in 1976
Causes 30% of diarrheal illness in developing countries
In the United States, transmitted via water

104. Figure 25.17 Cryptosporidiosis.
Intestinal
mucosa
Oocyst

105. Emerging Infectious Diseases
AIDS (acquired immunodeficiency syndrome)
Caused by human immunodeficiency virus (HIV)
First identified in 1981
Sexually transmitted infection affecting males and females
Worldwide epidemic infecting 35 million people; 6000 new infections every day
HIV/AIDS in the United States: 26% are female, and 49% are African American

106. Check Your Understanding
Differentiate normal microbiota and infectious disease
Why are biofilms important? 1-17
What factors contribute to the emergence of an infectious disease? 1-18