1. History of Microbiology

2. VOCABULARY
Fermentation: the enzymatic degeneration of carbohydrates in which the final electron acceptor is an organic molecule (contains carbon). For example, ATP is synthesized by phosporylation (adding phosphate) and oxygen is not required. Fermentation is the process that yeasts use to convert sugars to alcohol in the absence of air.
Pasteurization: the process of mild heating to kill particular spoilage microorganisms or pathogens.

3. VOCABULARY Aerobic: Requires environment with oxygen
Anaerobic: Requires environment without oxygen
Facultative: Can live in environments with and without oxygen.

4. Aristotle (384 B.C.)
Before Aristotle, people generally believed that diseases were caused only by God. He was one of the greatest scientists of his time. He theorized that ‘a vital force’ forms life. He noticed that mice were commonly found in barns where grain was stored. He thought that the mice grew from the grain and hay, and he coined the term “Spontaneous generation”, the hypothesis that living organisms arise from nonliving matter.
As a matter of fact, he published a recipe that anyone could use to grow their own mice: darkness + hay + grain = mice. No one doubted this for more than a thousand years. Eventually, a new theory arose called the Germ Theory (disease is caused by germs), later refined to the term “biogenesis”. Biogenesis is the hypothesis that living organisms arise from pre-existing life. For many years it was debated as to which of these hypotheses was correct.

5. Aristotle
Spontaneous Generation:
Mice grow from straw + darkness

6. Virgil (40 A. D.)
He agreed with Aristotle about spontaneous generation. He theorized that bees grew from honey and that flies grew from meat. Again, this was accepted for centuries.

7. Virgil
Bees grow from honey and flies grow from meat

8. The Romans (100 A.D.)
During the 1st century AD (year 100), glass had been invented and the Romans were looking through the glass and testing it.
They experimented with different shapes of clear glass and one of their samples was thick in the middle and thin on the edges.
They discovered that if you held one of these “lenses” over an object, the object would look larger.

9. The Romans (100 A.D.)
These lenses were not used much until the end of the 13th century when spectacle makers were producing lenses to be worn as glasses.
The early simple “microscopes” which were really only magnifying glasses had one power, usually about 6X - 10X.
One thing that was very common and interesting to look at was fleas and other tiny insects.
These early magnifiers were hence called “flea glasses”. 

10. The Romans
Used a magnifying lens called “Flea glasses”

11. Zacharias Janssen (1590)
He was a Dutch spectacle maker, and started experimenting with these lenses.
He put several lenses in a tube and made a very important discovery.
The object near the end of the tube appeared to be greatly enlarged, much larger than any simple magnifying glass could achieve by itself!
He had just invented the compound microscope (which is a microscope that uses two or more lenses). 

12. Zacharias Janssen
Invented the first compound microscope

13. Janssen’s First Microscope

14. Galileo (1610)
He heard of their experiments and started experimenting on his own.
He described the principles of lenses and light rays and improved both the microscope and telescope.
He added a focusing device to his microscope and of course went on to explore the heavens with his telescopes.

15. Galileo
Improved the microscope, Improved the telescope

16. Galileo’s First Telescope

17. Antoni Van Leeuwenhoek (Dutch parisitologist; 1673 - 1723)
He is called the Father of Microscopy, but he did not invent the first microscope.
He became very interested in lenses while working with magnifying glasses in a dry goods store.
He used the magnifying glass to count threads in woven cloth.
He became so interested that he learned how to make lenses.

18. Antoni Van Leeuwenhoek (Dutch parisitologist; 1673 - 1723)
By grinding and polishing, he was able to make small lenses with great curvatures.
These rounder lenses produced greater magnification, and his microscopes were able to magnify up to 270x.
He decided to look at what he thought would be the purest substance on earth: rainwater.
He was surprised that even this pure water contained live microorganisms (he called them animalcules) that he also observed in teeth scrapings.

19. Antoni Van Leeuwenhoek (Dutch parisitologist; 1673 - 1723)
He drew pictures of what he saw and defined names for bacteria based on their shape.
He called round bacteria cocci, rod shaped bacteria bacilli, and spiral bacteria spirochetes.
He also described movement of bacteria by observing Giardia lamblia in stool specimens.
He was the first person to record drawings of microbes and he introduced the world to the existence of microbes.
The Royal Society of London published his drawings in their journal.

20. Antoni Van Leeuwenhoek
Improved the simple microscope to a magnification of
270x
Described first microbes.

21. Antoni Van Leeuwenhoek

22. Leeuwenhoek’s Basic Shapes
COCCI
RODS
SPIRALS
Staphylococci
Streptococci

23. Arrangements Pairs: diplococci, diplobacilli Clusters: staphylococci
Chains: streptococci, streptobacilli

24. Robert Hooke (1685)
He spent much of his life working with microscopes and improved their design and capabilities.
He was the first to observe cells while looking at tree bark.
He reported that living things were composed of little boxes that he called “cells.”

25. Robert Hooke (1700’s)
Looked at cork under a microscope and coined the term “cells”

26. Robert Hooke

27. The Debate Over Spontaneous Generation
The hypothesis that living organisms arise from nonliving matter is called spontaneous generation. According to spontaneous generation, a “vital force’ forms life.
The alternative hypothesis, that the living organisms arise from preexisting life, is called biogenesis.

28. Francisco Redi Biogenesis Theory: Maggots do not grow from meat.
Filled covered jars with meat

29. Francisco Redi (1668)
He doubted the theory of spontaneous generation. He believed that maggots in meat were caused by flies laying eggs, not by spontaneous generation as commonly believed.
He filled six jars with decaying meat. He noted that no maggots grew in the meat when the jars were covered. It was argued that air was needed for the vital force to create life. Therefore, he put a cheesecloth over half of the jars so that flies could not come in and lay their eggs, but air could get in.
He demonstrated that maggots grew only in the meat in which the flasks were not covered. However, the theory of spontaneous generation persisted because of the religious beliefs of the time.

30. Francisco Redi

31. Evidence Pro and Con
1668: Francisco Redi filled six jars with decaying meat.
Conditions
Results
3 jars covered with fine net
No maggots
3 open jars
Maggots appeared
From where did the maggots come?
What was the purpose of the sealed jars?
Spontaneous generation or biogenesis?

32. John Needham
1780’s
Was an English biologist and Roman Catholic priest.
He believed in spontaneous generation.

33. John Needham (1749)
He was a biologist and a priest who believed in spontaneous generation and he argued Redi’s theory. He boiled nutrient broth to kill all microbes, put a cork in the flask, then let it sit for a few days. He then took a culture of the broth and found that it contained microbes. Thus, he “proved” that life comes only from God and a “vital force”. He then had the scientists and the Church on his side. He did not know that the cork stopper was not sterilized, so microbes on it dropped into the broth.

34. John Needham (1749)
For the next 30 years, various scientists who disagreed with spontaneous generation tried to disprove Needham’s experiment. One scientist said that Needham’s cork was contaminated, so he repeated the experiment except he sealed off the top of the glass by melting it; no microbes grew, so he said that spontaneous generation was false. His opponents said that the “vital force” that creates life is in the air, and that since he sealed off the air, the microbes could not spontaneously generate. Then other scientists would repeat the experiment with their own modifications. The debate over spontaneous generation raged on for 30 years, dividing the scientists from the religious clergy.

35. John Needham (1749)
In the meantime, much of the world’s commerce was on agriculture, so there was a great concern for keeping cattle and sheep alive. The major diseases of this era were anthrax, the Black Plague, smallpox, and leprosy. There were also concerns about diseases of the money-making crops, including grapes, tobacco, and silkworms. While some scientists continued the debate over spontaneous generation, others turned their attention to the diseases at hand.

36. John Needham Put boiled nutrient broth into covered flasks.
He got microbial growth, so he said this is evidence for spontaneous generation.
However, his experiment was flawed because the flasks and corks were not sterile.

37. 1745: John Needham put boiled nutrient broth into covered flasks.
Conditions
Results
Nutrient broth heated, then placed in sealed flask
Microbial growth
From where did the microbes come?
Spontaneous generation or biogenesis?

38. Louis Pasteur
Microorganisms are present in the air

39. Louis Pasteur (1880)
150 years later, Pasteur joined the spontaneous generation debate.
He made a glass flask with an “S” shaped bend in it so that bacteria could not enter into it.
He placed chicken broth in the flask and boiled it so that it was sterile.
Over the next few weeks, he observed that there was no bacterial growth in the broth, so this proved that spontaneous generation was impossible.
No bacteria could grow unless pre-existing bacteria were able to get in to the nutrient broth.
That ended the debate and the theory of spontaneous generation was rejected and the theory of biogenesis was accepted.

40. 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 sealed
No microbial growth
Spontaneous generation or biogenesis?

41. Louis Pasteur

42. The Theory of Biogenesis
Pasteur’s S-shaped flask kept microbes out but let air in.
Figure 1.3

43. Spontaneous Generation Theory
Aristotle thought that the mice grew from the grain and hay, and he coined the term “Spontaneous generation”
Virgil: bees grew from honey and that flies grew from meat.
John Needham believed in spontaneous generation; boiled nutrient broth to kill all microbes, put a non-sterile cork in the flask, found that the broth grew microbes.

44. Biogenesis Generation Theory
Redi: maggots in meat were caused by flies laying eggs; they only grew on the meat in which the jars were not covered.
Louis Pasteur: made a glass flask with an “S” shaped bend in it so that bacteria could not enter into it but air could get in. He placed chicken broth in the flask and boiled it so that it was sterile and observed that there was no bacterial growth in the broth.

45. Edward Jenner
First vaccine:
Smallpox

46. Edward Jenner, MD (1796)
Jenner invented the first vaccine; it was for smallpox, the first disease to be eliminated from the earth by vaccine. Some of his patients, especially women who milked cows, would come in with lesions filled with pus on their hands. He went to their farms to examine the cattle and noticed lesions on the udders of the cattle as well.

47. Edward Jenner, MD (1796)
Around this time smallpox was greatly feared, as one in three of those who contracted the disease died, and those who survived were commonly badly disfigured. Noting the common observation that milkmaids did not generally get smallpox, Jenner theorized that the pus in the blisters which milkmaids received from cowpox (a disease similar to smallpox, but much less virulent) protected the milkmaids from smallpox. In 1796, Jenner tested his theory by inoculating James Phipps, a young boy, with material from the cowpox blisters of the hand of Sarah Nelmes, a milkmaid who had caught cowpox from a cow called Blossom. Phipps was the 17th case described in Jenner's first paper on vaccination.

48. Edward Jenner, MD (1796)
Jenner inoculated Phipps with cowpox pus in both arms on one day. This produced a fever and some uneasiness but no great illness. Later, he injected Phipps with variolous material, (weakened smallpox). No disease followed. Jenner reported that later the boy was again challenged with variolacious material and again showed no sign of infection.
Thus, he discovered that a genetically related microbe could produce immunity to the smallpox pathogen.
The word vaccination comes from the Latin vaccinia, cowpox, from vacca, cow.
In 1980, the World Health Organization declared smallpox an eradicated disease.

49. Edward Jenner

50. Rudolf Virchow Cell Theory All living things are composed of cells.
Cells are the smallest working units of living things.
3. All cells come from preexisting cells by cell division (biogenesis theory).

51. Agostino Bassi
Silkworm disease is caused by a fungus

52. The Golden Age of Microbiology (1880-1930)
Louis Pasteur ( )
Once the debate over spontaneous generation was over, the Golden Age of Microbiology began.
Pasteur coined the terms “fermentation”, “pasteurization, and the “Germ Theory of Disease”.
Louis Pasteur went on to discover three vaccines; the first was by accident.

53. The Golden Age of Microbiology (1880-1930)
During his time, chicken cholera was hurting the poultry industry. Pasteur made a pure culture of chicken cholera and told his assistant to inoculate a chicken.
They both left on vacation and forgot to inoculate the chicken. When they came back, they inoculated the chicken with the same culture, which had run out of nutrients and had become weak.
They found that the chicken never developed symptoms. They then tested all of the chickens to make sure that weakened culture did not cause symptoms in any chickens.
They then exposed the chickens to chicken cholera and none of them became sick. They therefore discovered the concept of an immune system.

54. The Golden Age of Microbiology (1880-1930)
They found that the old culture was weakened (he called this “attenuated”), and thus he discovered how to make the first vaccine for chicken cholera.
Later, he found the causative agent for anthrax and invented the sheep anthrax vaccine.
He also invented the rabies vaccine.
A vaccine is a form of artificial immunity.

55. Pasteur: Sheep Vaccine for Anthrax

56. The Golden Age of Microbiology (1880-1930)
Louis Pasteur went on to work with anthrax, silkworm disease, and rabies. He developed the first vaccine for rabies, which is a disease that spreads to the brain and spinal cord. Rabies is caused by a virus and is too small to see under a microscope. Therefore, he was the first to work with human diseases caused by viruses. He worked with rabbits that had rabies; he dissected out the spinal cords, put them in a jar, let them dry for a few weeks, ground them up into a powder, and made his suspension. He then inoculated dogs with this rabbit tissue. When the dogs were exposed to rabies, they did not get the disease.

57. The Golden Age of Microbiology (1880-1930)
A young boy named Joseph Meister was bitten by a rabid animal. Back then, everyone who was exposed to rabies died. Pasteur injected the boy’s abdomen with a vial of the spinal cord suspension once a week for 12 weeks. He was the first person to survive rabies. After Louis Pasteur died, Joseph became a caretaker of Pasteur’s estate. During World War II the Nazis invaded Paris. They wanted to raid Pasteur’s tomb, but rather than allow that, Joseph committed suicide.

58. Robert Koch

59. Robert Koch, MD (1890)
Unlike Pasteur, Koch was an MD, and he worked with a team of scientists, rather than alone, like Pasteur. He developed “Koch’s Postulates” which establish the cause of disease. This was developed using the scientific method, including stating a hypothesis and drawing a conclusion. He studied anthrax in sheep and cattle, and he also discovered the cause of tuberculosis. He is the one that proved the link between microbes and disease. He demonstrated that a specific microbe causes a specific disease.

60. Koch’s Postulates
Obtain the disease causing microbe from the sick animal via a sample.
Isolate this microbe in pure culture.
Inoculate a healthy animal with this pure culture, and the healthy animal should develop the same disease.
Re-isolate the microbe from the second animal. If it is the same microbe obtained from the first animal, this proves the etiology (cause) of the disease.

61. Joseph Lister

62. Joseph Lister ( )
During his lifetime, 50% of people who had surgeries died from post-op infections. It was thought that exposure of a wound to oxygen caused the infection, but Lister doubted that explanation. He was put in charge of a new hospital in London that was designed to keep air away from post-op wounds. However, 50% of the amputation cases still were dying.
Then, in 1865, when Louis Pasteur suggested that decay was caused by living organisms in the air, Lister made the connection with wound sepsis. He considered that microbes in the air were likely causing the putrefaction and had to be destroyed before they entered the wound.

63. Joseph Lister ( )
In the previous year Lister had heard that carbolic acid was being used to treat sewage in cattle fields that were causing a parasite disease in the cattle.
Lister began to clean wounds and dress them using a solution of carbolic acid. He reported that the surgery patients were now recovering without infections. In 1877 he performed the first surgery using aseptic conditions, including sterilization of instruments and hand washing before surgeries.
Thus, he is the founder of aseptic medicine.
Later, his product was refined by another doctor who named it Listerine® after Dr. Lister. 

64. Operation using Lister's carbolic spray invented in 1869

65. Ignaz Semmelwise
Puerperal fever could be drastically cut by use of hand washing standards in obstetrical clinics.

66. Ignaz Semmelwise (1847)
Discovered that the incidence of puerperal fever could be drastically cut by use of hand washing standards in obstetrical clinics.
Puerperal fever (or childbed fever) was common in mid-19th-century hospitals and often fatal, with mortality at 10%-35%.
He also advocated that midwives should wash their hands when going from one obstetric patient to another to prevent transmission of puerperal fever.

67. Paul Ehrlich
First Antibiotic:
For syphilis

68. Paul Ehrlich (1854 –1915)
He coined the term "chemotherapy" and developed the first antibiotic drug in modern medicine. They called it the “magic bullet”; it was the cure for syphylis.
 After his clinical education in Berlin in 1886 he received a call from Robert Koch to join the Institute for Infectious Diseases in Berlin (1891).
 Ehrlich spent two years in Egypt, recovering from tuberculosis. Thereafter he worked on the development of the diphtheria serum.

69. Paul Ehrlich (1854 –1915)
Ehrlich received the Nobel Prize for Medicine in 1908.
In 1906 he discovered the structural formula of atoxyl, a chemical compound that had been shown to be able to treat sleeping sickness.
Following this discovery, he tried to create a less toxic version of the medicine. In 1909, on his 606th attempt, he developed Salvarsan, an antibiotic effective against syphilis.
This was the first antibiotic; his work was of epochal importance, stimulating research that led to the development of sulfa drugs, penicillin and other antibiotics.

70. Paul Ehrlich

71. Von Behring (1901) Invented diphtheria antitoxin
First to study how a toxin (Diptheria) can be neutralized by an antitoxin. He was the first person to receive a Nobel Prize in medicine.

72. Ross
Discovered mosquitoes transmit malaria

73. Metchnikoff Discovered White Blood Cells and phagocytosis:
Began field of immunology

74. Metchnikoff (1908)
Discovered that white blood cells phagocytize (eat) foreign particles as a fundamental part of the immune response.
He studied mobile, amoeba-like cells (later known as white blood cells) in starfish.
He thought they served as part of the defenses of these organisms and, to test this idea, he stuck the starfish with small thorns from a tangerine tree which had been prepared as a Christmas tree for his children.

75. Metchnikoff (1908)
Next morning he found the thorns surrounded by the mobile cells, and, knowing that, when inflammation occurs in animals which have a blood vascular system, leukocytes escape from their blood vessels, it occurred to him that these leukocytes might take up and digest bacteria that get into the body.
This began the field of immunology.

76. Alexander Fleming

77. Alexander Fleming ( )
Fleming is the key person involved in the discovery of penicillin.
One morning in the fall of 1928, Fleming noticed a culture plate displaying a colorful green mold.
The culture plate was covered with staphylococci except in the vicinity of the mold, which was near the edge of the plate where there was a transparent zone of inhibition.
The bacteria that were close to the mold had not grown.

78. Alexander Fleming ( )
Since his mind was prepared by his previous studies, Fleming knew he might be on to something that kills bacteria.
He photographed the plate and made it permanent by exposing it to formalin vapor that killed and fixed both the bacteria and the mold. (The original plate is now in the British Museum.)
Fleming investigated a list of microorganisms that were inhibited by the mold; among them were streptococci, staphylococci, pneumococci and meningococci.

79. Alexander Fleming ( )
Fleming identified the mold as a Penicillium that is similar some molds grown on bread.
In 1945 Fleming received the Nobel Prize in Medicine and Physiology for his work with penicillin.
NOTE: antibiotics are chemicals that kill bacteria. It is not the same thing as an antibody, which is a white blood cell’s natural protein that kills bacteria.

80. The Birth of Modern Chemotherapy
1928: Alexander Fleming discovered the first antibiotic.
He observed that Penicillium fungus made an antibiotic, penicillin, that killed S. aureus.
1940s: Penicillin was tested clinically and mass produced.
Figure 1.5

81. Chain and Florey Purified penicillin as a medicine
The biggest problem was how to produce large quantities of penicillin, especially for casualties during WWII. American scientists Chain and Florey were successful in producing it for large-scale manufacture.

82. Rebecca Lancefield: Invented testing for streptococcus

83. Rebecca Lancefield (1895 - 1981)
American microbiologist. She is most famous for her serological classification of streptococcal bacteria based on the antigens in the cells walls.
She also demonstrated that one of these groups, group A streptococci (S. pyogenes), was specific to humans and human disease, including pharyngitis ("Strep throat"), scarlet fever, rheumatic fever, and impetigo. Group B streptococci were subsequently shown to be associated with neonatal disease.

84. Lancefield’s Streptococcus Classification

85. Frederick Griffith (1928)
Discovered DNA

86. Watson and Crick
Detailed the structure of human DNA.

87. Watson and Crick (1953)
Opened up the second golden age of microbiology when they discovered the structure of the DNA molecule in Watson and Crick were awarded the 1962 Nobel Prize award, for their body of research on nucleic acids. Their work became the basis for the Human Genome Project, which was a world-wide effort to list all of the sequences of nucleic acids in human DNA. This knowledge is helping to understand genetic disorders. This also opened up the field of Molecular Genetics, understanding how genes work at a molecular level.

88. DNA Structure Deoxyribose (sugar) A, T, C, G (nucleic acids)
Phosphate (to form the bonds)

89. Jacob and Monod (1965)
Role of mRNA in protein synthesis

90. Protein Synthesis

91. Delbruck and Hershey
Structure of viruses

92. Virus

93. Tonegawa (1987) Antibody genetics
Genetic material can rearrange itself to form the vast array of available antibodies.

94. Prusiner (1997) Discovery of prions
Prions are simpler than viruses and can cause disease. They have no DNA or RNA. They cause a brain disease called spongiform encephalopathy (bovine form is Mad Cow Disease).

95. Prions

96. SELECTED NOBEL PRIZES IN PHYSIOLOGY
1901 Behring diphtheria antitoxin
1902 Ross malaria transmission
1905 Koch TB bacterium
1908 Metchnikoff phagocytosis
1945 Fleming, Chain, Florey penicillin
1969 Delbruck, Hershey viral replication
1987 Tohegawa antibody genetics
1997 Prusiner prions