Unit 1

1. Unit 1 The Development of Microbiology

2. Do Now • What was the last illness you had? • How sick did you feel? • Do you know if it was caused by a microorganism? Which one?

3. The Beginnings • Robert Hooke 1665: • Introduced the world to small objects and creatures when he published his journal – Micrographie • It contained illustrations of • Eye of a fly • Stinger of a bee • Shell of a protozoan • Plant-like mold • Cork cells

4. The Beginnings • Zacharias Janssen: • Spectacle maker from the Netherlands • Invented the microscope

5. The Beginnings • Anton van Leeuwenhoek 1670’s • Seller of silk, wool, and cotton in the Netherlands • Enhanced Jansenn’s microscope for use in his business • But his fascination with the microscope led him to examine hair fibers, blood cells and even his own feces

6. The Beginnings • Anton van Leeuwenhoek (continued) • Looked at marshy lake water which teemed with microorganisms – he called them animalcules • He contacted the Royal Society of London and sent them letters and drawings of his studies • But, he was very suspicious and didn’t let any one know how to make his lenses • He also never made the connection between microorganisms and disease

7. The Transition Period • Biology of the 1700’s consisted of observations of plant and animal life and attempts to classify them (Linnaeus) • Scientists did not think of infection in terms of tiny living organisms • Believed that an infectious disease spread by a miasma - an altered chemical quality of the atmosphere which arose from diseased bodies - miasmas • This miasma theory was believed well into the 1800’s and gradually dissipated with the realization that microorganisms caused infectious disease

8. Do Now • 1. Who invented the microscope? • 2. Who improved or enhanced the microscope? • 3. What is the name of the chemical quality of the atmosphere that 1700’s scientists believed caused infectious disease?

9. Spontaneous Generation • In the 1700’s many scientists believed that life comes from non-living things • Living conditions - Why does meat get maggots? • They come from the meat! • Francesco Redi did not agree with this

10. Spontaneous Generation • REDI’S EXPERIMENT 1668

11. John Needham 1748 • Needham agreed with spontaneous generation • He boiled bottles of broth (gravy) and said heating would kill any organisms already in it • He then capped the bottles of broth – no air could enter • After several days, the bottles were contaminated with microorganisms • He concluded that they arose from the broth and spontaneous generation does occur

12. LAZZARO SPALLAZANI b. 1729 • He knew about Redi and Needham’s experiments and he thought Needham was wrong • So, Spallanzani did not believe in spontaneous generation • What mistake do you think he thought Needham had made in his experiment?

13. LAZZARO SPALLAZANI b. 1729 • He thought Needham hadn’t boiled the broth enough • He decided to run his own version of the experiment • He thoroughly boiled the broth and stored some in an open container and some in a closed container • After several days he saw…… • No microorganisms in the sealed bottle, and tons in the unsealed bottle

14. Spallanzani’s Experiment

15. LAZZARO SPALLAZANI b. 1729 • Microorganisms do not come from broth – non-life • They come from the air! • If this were not so then both jars would have organisms • But many still believed in Spontaneous Generation – they said that it required oxygen and Spallanzani had blocked it out

16. Disease Transmission • People still believed the Miasma Theory of infection because then people were not at fault for spreading disease • In 1847 Ignaz Semmelweis, a Hungarian doctor, reported that the agent of blood poisoning was transmitted to maternity patients by doctors that had just performed autopsies • He said that hand washing in chlorine water would stop the spread of disease – no one listened

17. Disease Transmission • John Snow, a British doctor traced the source of an 1854 cholera epidemic to London’s municipal water supply • He said that if people avoided the water, they would avoid the disease • People listened and the spread of the disease was stopped • These 2 doctors showed that disease was caused by an unseen object in the environment – not a miasma.

18. Do Now • 1. Briefly describe Francesco Redi’s experiment. What was he trying to disprove? • 2. Did John Needham agree with Redi? • 3. Briefly describe Lazzaro Spallanzani’s experiment. What was his conclusion?

19. The Golden Age • The science of microbiology blossomed for about 60 years, beginning in 1857 • It began with a scientist named Louis Pasteur and ended about the time of WWI • Numerous branches of microbiology were established and the foundations for modern microbiology were laid down

20. Louis Pasteur’s World • In the 1800’s, the world was ravaged by plague, tuberculosis, typhoid fever, and diphtheria. • It was necessary to have a large family to ensure the next generation • Even royalty could not avoid disease • No one was sure what caused disease – no cures

21. Louis Pasteur - Fermentation • Believed that scientific discoveries should have practical applications • He wanted to find out why local wines were turning sour • At the time people thought that wine fermentation resulted from the chemical breakdown of grape juice into wine. • They didn’t know any living creatures were involved

22. Louis Pasteur – Fermentation • But Pasteur’s microscope revealed large numbers of tiny yeast cells • He correctly believed that the yeasts played a major role in fermentation • In an experiment he removed all yeast from grape juice and it did not ferment • Then he added the yeast back and it did ferment into wine • He suggested that grape juice be heated to destroy all life before fermentation was begun - pasteurization

23. Louis Pasteur - Bacteria • Pasteur also noticed that the sour wines contained tiny sticks and rods known as bacteria • He did an experiment where he removed all bacteria from grape juice • The when he mixed it with yeast it could ferment and not turn sour

24. Louis Pasteur – Germ Theory • Pasteur’s discoveries shook the scientific community • He demonstrated that yeast cells and bacteria were tiny living factories where important chemical changes were occurring • He also showed microorganisms could be agents of change – they could cause a disease rather than being an effect of the disease • Germ Theory of Disease – microorganisms are responsible for infectious diseases

25. LOUIS PASTEUR • People still believed in spontaneous generation! • Pasteur decided to end the debate once and for all with an ingenious experiment

26. LOUIS PASTEUR

27. Pasteur’s Conclusion • He said that life comes from LIFE! • This is called Bio-genesis • Pasteur’s work brought to an end the debate of spontaneous generation • Now scientists had to concentrate on connecting certain microorganisms to specific diseases

28. Do Now • 1. What did Pasteur conclude was causing the fermentation of grapes into wine? • 2. What did he show was causing the wine to turn sour? • 3. What is the germ theory of disease? • 4. What did Pasteur’s swan neck experiments disprove?

29. Robert Koch • Koch was a country doctor from East Prussia (now Germany) who was concerned with anthrax which infected cattle and sheep • In a lab in his home, he injected mice with the blood of diseased cattle, then performed autopsies on the dead mice • Next he isolated a few bacteria from a mouse’s blood and placed it in the sterile aqueous humor from an ox’s eye

30. Robert Koch • He watched as the bacteria multiplied and then turned into resistant spores • Next he took several of the spores and injected them into healthy mice • The symptoms of anthrax appeared within hours • Koch autopsied the mice and found their blood swarming with bacteria

31. Robert Koch

32. Robert Koch’s Postulates

33. Solid Culture Media • Koch developed a solid culture media on which bacteria would grow by solidifying beef broth and gelatin • When inoculated onto the surface, bacteria grew vigorously and produced discrete visible, colonies • Now agar is used instead of gelatin because it can resist digestion by certain bacteria and it remains solid when incubated at high temperatures

34. End of the Golden Age • The Golden Age witnessed a series of discoveries unparalleled in the identification of the agents of disease • Scientists developed an awareness that infectious disease was caused by microorganisms and that the chains of transmission could be broken • These discoveries led to calls for sterile practices in hospitals, pasteurization of milk, purification of water, control of insects and care in the preparation of foods • This led to a substantial reduction in the incidence of bacterial diseases – but viruses were still to come!

35. Compound Light Microscope

36. Light Path

37. Light Path

38. Oil Immersion

40. Wheat Rust • A disease of wheat caused by a fungus of the genus Puccinia • Infections can lead up to 20% yield loss - exacerbated by dying leaves which fertilize the fungus • Small brown pustules develop on the leaf blades in a random scatter distribution. They may group into patches in serious cases. Infectious spores are transmitted via the soil.