Lecture 1 - The scope and history of microbiology. Based upon chapter 1 from "Microbiology: A Systems Approach" by Cowan.

1. The Scope and History of Microbiology Assigned Reading:Chapter 1, pp 1-26

2. What is Microbiology? micron = small and biologia = studying life How small is “small”? Study of entities too small to be seen with the naked eye (< 0.1 mm) Different perspectives of microbiology: Collection of disciplines by organism Confluence of disciplines to study microbes Microbes have changed history Microbes have changed science Microbes have changed the Earth

3. Diversity of Microbiology

4. Microorganism Sizes

5. Sub-Disciplines Fields are historically arranged by the type of microbial system under investigation Bacteriology: Bacteria and Archaea Mycology: Fungi Phycology: Algae Protozoology: Protozoa Virology: Viruses Immunology: The immune response

6. Microbes Have Changed History Although not always recognized at the time, microbes have dramatically altered human history. Microbes working with us: Food preservation and preparation for instance Beer, wine, bread, cheese, sauerkraut, yogurt… Microbes working against us: Many microbial diseases have altered the outcome of historical events.

7. History-Altering Microbes Malaria - Plasmodium falciparum (Protozoan) Mosquito-borne infectious disease Thought to have killed Alexander the Great (323 BC) Still an important pathogen Infects ~400,000,000 annually Kills ~2,000,000 annually that is over 5,000 every day!

8. History-Altering Microbes Bubonic plague - Yersinia pestis (Bacterium) Vector-borne septicemia Black Death (1347-1351) Between 25-40% of Europe died Loss of laborers contributed to the collapse of the feudal system Lead to the Peasant’s Revolt of 1381 Still endemic around the world

9. History-Altering Microbes Smallpox (Virus) Directly transmissible disease This disease was a big problem in Europe and Asia Variola major has a 40% mortality rate Hernán Cortéz landed in Mexico in 1519 Smallpox was brought to the Americas Aztec civilization was decimated Spanish rule over the region was enabled Eliminated by vaccination in 1979

10. History-Altering Microbes Potato Blight - Phytophthora infestans (Fungus??) Irish potato famine (1845-1849) Potato crops were wiped out ~1,000,000 starved to dead ~2,000,000 emigrated Many came to the United States in the mid-1800s Still a chronic problem for potato farmers

11. Developments in microbiology altered our views of the scope, diversity, and origin of life The germ theory altered our views on the cause, treatment, and prevention of illness The advent of molecular biology and initial advances in genetics were largely driven by microbiologists Microbiology and its offshoots represent the majority of modern biological science Microbes Have Changed Science

12. Anton Von Leeuwenhoek 1684 Dutch lens maker First person to see and describe living microbes Simple microscope 70 to 250X magnification Made and reportedmany detailedobservations

13. Aristotle 400 BC – Supported Philosopher and early naturalist Made detailed observations of nature Concluded that aphids, fleas, flies, and even mice could spontaneously form from other organic substrates

14. Francesco Redi 1668 - Against Italian natural philosopher Uncovered dishes of meat filled with maggots Covered dishes of meat attracted flies, but maggots formed on the gauze - not the meat Disproved spontaneous generation of maggots

15. Louis Joblot 1710 - Against French mathematician Boiled hay infusions Open container became cloudy Sealed container remained clear Argued that contamination come from outside of the container

16. John Needham 1745 - Supported English scientist Boiled mutton broth Growth observed in both open and closed flasks after boiling Inadequate boiling probably Argued that the growth was intrinsic to the nature of the broth

17. Lazzaro Spallanzani 1768 - Against Italian priest Repeated Needham’s experiment Boiled sealed flasks No growth in flasks until opened Argued that Needham must have contaminated his flask when closing it

18. Franz Schulze 1836 - Against After Priestly discovered oxygen Unheated gasses passed through concentrated acid or base solutions No growth observed inboiled broth media

19. Theodor Schwann 1836 - Against German physiologist Best known for work with nerve tissue Heated incoming gas No growth observed inboiled broth media

20. Louis Pasteur 1864 - Against French microbiologist Used swan-necked flasks Untreated air allowed in and out of flasks No growth in undisturbed flasks Contacting the broth with the dust results in rapid microbial growth

21. John Tyndall 1876 - Against English physicist Built elaborate boxes to eliminate dust Discontinuous heating used to kill endospores Finally laid abiogenesis to rest Oparin and Haldane

22. Oliver Wendell Holmes American physician – 1834 Observed the apparent spread of puerperal fever (Streptococcus) by health care providers Published findings with guidelines to reduce transmission Results largely ignored for twenty years

23. Ignatz Semmelweiss Vienna physician - 1841 Puerperal fever outbreak was severe in his hospital Observed a difference in incidence in clinical wards Forced hand washingwith chlorinatedlime solutions Before germ theory Unpublished and largely ignored

24. Louis Pasteur French microbiologist - 1862 Was contacted by wine producers with a problem The wine was going sour Pasteur thought that the wine was “infected” with detrimental microbes He briefly heated the wine to kill these microbes Advent of pasteurization Also postulated that if wine can be infected by microbes, people can too This is the beginning of the germ theory of disease.

25. Joseph Lister British surgeon - 1867 Applied germ theory to the treatment and prevention of disease Used carbolic acid (phenol) to clean wounds and operating rooms Disinfection Antisepsis

26. John Snow British doctor - 1854 Cholera outbreak in Soho Tracked incidence in the population Traced source to contaminated drinking water Epidemiology

27. Robert Koch German microbiologist Contemporary of Pasteur Worked on anthrax, tuberculosis, and cholera Used pure cultures Developed the germ theory of disease Described several postulates for proving the etiological agent of disease (1884)

28. Koch’s Postulates

29. Edward Jenner English physician - 1789 Studied smallpox outbreaks Variolation had been used Rather dangerous Cowpox was noted to cause mild lesions in milk maids Used the cowpox virus (vaccinia) to protect against smallpox The first “vaccination”

30. Advent of Chemotherapy Aniline dyes were observed to inhibit microbial growth Salvarsan - discovered by Ehrlich (1908) Arsenic compound that inhibited syphilis Penicillin - Fleming (1928) Commercially available in the 1939 Protosil - first sulfa-drug Domagk (1935) Also the first drug to be used commercially Streptomycin - Waksman and Schatz (1944) Second antibiotic

31. Molecular Biology Many of the most critical development of modern molecular biology were worked out in microbes Griffith and Avery study transformation Lederberg developed bacterial genetics Meselson and Stahl studied DNA replication Hershey and Chase study bacteriophage Howard Berg performed first cloning Keri Mullis developed PCR We will revisit these scientists throughout the course.

32. Taxonomy Kings Play Chess On Fine Green Satin Binomialnomenclature

33. New Views of Phylogeny Whittaker versus Woese

34. Microbes Change the Earth What effect would there be if you removed every human from the earth today? What effect would there be if you removed every mammal from the earth today? What effect would there be in you removed every microbe from the earth today? Microbes cycle all of the biologically important elements on the planet Availability of N, S, P, O, and C are regulated by microbes

35. Microbial Ecology Beijerinck - Used enrichment cultures to identify environmental isolates Also discovered the first virus Winogradsky - Used similar techniques to identify nitrogen fixers and chemoautotrophs They began to work out the biochemical roles that microbes play in the environment. Carl Woese - 16S sequencing revealed the archaea Now we begin to appreciate the true diversity of microbes