1. A Brief History of Microbiology The Microbes of Microbiology
Intro to Microbiology
A Brief History of Microbiology
The Microbes of Microbiology
Updated 1/2011

2. What is Microbiology?

3. Why should we study Microbiology?

4. Why should we study Micro?
Can be used to produce food, medicines, and more.
Help protect us from pathogens by taking up space and activating our immune system. Make us healthy by producing vitamins.
10X more bacteria than our own cells
Help plants absorb nutrients and grow faster
Microbes form the base of the food chain.

5. Understanding microbes is vital for other study of life!
Conclusion:
Understanding microbes is vital for other study of life!

6. Advances in microbiology have followed advances in technology
And vice-versa…

7. The Early Years of Microbiology
Anton van Leeuwenhoek (Dutch)
Began making and looking through simple microscopes
Examined water, semen, teeth scrapings ~1683
Visualized tiny animals, fungi, algae, and single celled protozoa; “animalcules”
By end of 19th century, these organisms were called microorganisms

8. 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?

9. Is Spontaneous Generation of Microbial Life Possible?
Aristotle proposed spontaneous generation
living things can arise from nonliving matter
Explained many observations
Theory came under challenge in 17th century
Redi’s Experiments (late 1600s)
Needham’s Experiments (mid 1700s)
Spallanzani’s Experiments (1799)
Pasteur’s Experiments (mid 1800s)

10. Redi’s Experiments Meat exposed to flies developed maggots, when
meat is kept isolated maggots do not develop
Conclusion: Animals only come from other animals.
After Leeuwenhoek discovered microbes scientists assumed that microbes arose spontaneously
Thought they were too small/simplistic to reproduce
Incorrect conclusions misled scientists.

11. The Scientific Method
Debate over spontaneous generation led in part to development of scientific method
Observations lead a scientist to ask questions about some phenomenon
The scientist generates hypothesis (potential answer to question)
The scientist designs and conducts experiment to test hypothesis
Based on observed results of experiment, scientist either accepts, rejects, or modifies hypothesis

12. Louis Pasteur Performed a similar experiment to Spallanzani
Instead of completely sealing his flasks he bent the necks which allowed air to enter but prevents contamination
Flasks remained pure until they were exposed to dust
Conclusion: Microbes in the flask are the progeny of microbes on the dust
Pasteur also researched Fermentation and Infection

13. Cell Theory Pasteur’s evidence and conclusions led to the cell theory.
The cell is the fundamental unit of Life.
All organisms are made of cells.
All cells come from previously existing cells.

14. What Causes Disease? Pasteur developed germ theory of disease
Microbes are responsible for disease
Robert Koch studied causative agents of disease
Anthrax
Examined colonies
of microorganisms
Developed
Koch’s Postulates

15. Koch’s Postulates
Suspected causative agent must be found in every case of the disease and be absent from healthy hosts(a)
Agent must be isolated and grown outside the host(b).
When agent is introduced into a healthy(c), susceptible host, the host must get the disease(d).
Same agent must be re-isolated from diseased experimental host(e,f)

16. Laboratory Microbiology Advances by Koch and Others
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
Aseptic techniques
Bacteria as distinct species

17. How Can We Prevent Infection and Disease?
Semmelweis and handwashing
Lister’s antiseptic technique
Nightingale and nursing
Snow and epidemiology – infection control and epidemiology
Jenner’s vaccine – field of immunology
Ehrlich’s “magic bullets” – field of chemotherapy

18. The Modern Age of Microbiology
What are the basic chemical reactions of life?
Biochemistry
How do genes work?
Microbial genetics, Molecular biology, Recombinant DNA technology, Gene therapy
What role do microorganisms play in the environment?
Environmental microbiology
How do we defend against disease?
Serology, Immunology, Chemotherapy

19. Meet the Microbes! Microorganisms we will study:
Fungi, Protozoa, Algae, Bacteria, Archaea, certain Animals
Non-living particles are also included:
Viruses, virons, prions
No plants!

20. Fungi Eukaryotic (have membrane-bound nucleus)
Obtain food from other organisms
Possess cell walls of chitin
Examples:
Molds – multicellular; have hyphae; reproduce by sexual and asexual spores
Yeasts – unicellular; reproduce asexually by budding; some produce sexual spores
[Mushrooms – not discussed in Microbiology]

21. Protozoa (Protist) Single-celled eukaryotes
Pseudopods
Cilia
Flagella
Protozoa (Protist)
Single-celled eukaryotes
Similar to animals in their nutritional needs and cellular structure
Most reproduce asexually; some sexually
Sometimes classified by type of movement

22. Algae (Protist) Unicellular or multicellular Photosynthetic
Categorized by:
Pigmentation
storage products
cell wall composition

23. Bacteria and Archaea Unicellular and lack nuclei
Much smaller than eukaryotes
Found everywhere there is sufficient moisture; some found in extreme environments
Use every type of metabolism
Reproduce asexually

24. Two Groups of Prokaryotes
Bacteria
Cell walls contain peptidoglycan (some lack cell walls)
most do not cause disease and some are beneficial
Archaea
cell walls composed of polymers other than peptidoglycan
Some live in extreme environments, none identified that cause disease
Methanopyrus kandleri Copyright K.O.Stetter and R.Rachel, Univ. Regensburg, Germany

25. Other Microbes of Importance
Animals
Eukaryotic, multicellular, heterotrophs
Parasites or vectors for other diseases
Viruses
Non-cellular infectious particles
DNA or RNA in a protein coat
Viroids
Smaller than viruses
RNA without protein or protein genes
Prions
Infectious proteins