1. Lecture 1 Intro to Microbiology: History and Taxonomy

2. Microbiology
The study of organisms to small to be seen without a microscope
Includes living microorganisms: bacteria, algae, fungi, protozoa
AND non-cellular infectious agents: viruses, viroids, prions

3. Why study Microorganisms?
Microorganisms are the foundation for all life on earth
They effect your everyday life
Only a minority of microorganisms are pathogenic
Microorganisms are found almost everywhere

4. Microbes and Human Welfare
Recycle chemical elements
Decompose organic matter
Bioremediation
Biotechnology
Gene therapy
Genetic engineering

5. Microbes can be used to clean up oil spills such as this one in Alaska
Courtesy of the Exxon Valdez Oil Spill Trustee Council/NOAA

6. Microbes and Human Disease
Everyone has microbes in and on body
Person may or may not contract disease once they are in contact with it

7. Infectious Disease Pathogens invade susceptible host
Emerging infectious diseases
Ebola
BSE, Mad cow disease
Know other emerging infectious diseases from book for exam

8. Major Groups of the Microbial World
Bacteria
Archeae
Fungi
Algae
Protozoans
Helminths
Viruses
Major Features
Small size
Diverse appearance
Diverse genetics

9. Bacteria

10. Archaea
Found in extreme environments

11. Fungi

12. Fungi

13. Algae

14. Protozoa

15. Helminths

16. Viruses

18. The Spectrum of Microorganisms is Diverse
- There are over 10 million species of prokaryotes
There are over 3600 known viruses
There are about 70,000 described species of fungi

19. Discovery of Microorganisms
Robert Hooke published Micrographia (1665)
Anton van Leeuwenhoek ( )
He peered at a drop of lake water through a lens that he carefully ground -

20. Hooke’s Micrographia
© Library of Congress [LC-USZ ]

21. Cork cells
© Library of Congress [LC-USZ ]

22. Anton van Leeuwenhoek
Courtesy of Pfizer, Inc.

23. Leeuwenhoek’s drawings of bacteria
Courtesy of Royal Society, London

25. Next Question: Where did microorganisms originate?
Spontaneous generation: Life originates from non-life, believed from the time of Aristotle ( B.C.)
Works of Redi, Pasteur, and Tyndall refute this theory
Prove Germ Theory of Disease -

26. Francesco Redi ( )
Proponents of spontaneous generation believed that worms in rotting meat came from meat itself
Redi debunked this theory
Experiments with meat

27. New Experiments Needed to Refute Spontaneous Generation
Typical Experiment: used nutrient broth (infusion): contains nutrients needed for microorganisms to grow
1. boil to kill all forms of life
2. seal vessel
If cloudy after standing: spontaneous generation
If clear: no spontaneous generation
Different investigators: Different results -

28. Louis Pasteur (1822-1894) Father of microbiology
Demonstrated air is filled with microorganisms
Demonstrated that sterile infusions will stay sterile in specially constructed flasks even when they were left open to the air

30. John Tyndall
Explained differences in results obtained from different laboratories
Proved Pasteur correct
He concluded that different infusions require different boiling times to be sterilized
Because of heat resistant microorganisms: Endospores

31. Endospores Some microorganisms exist in two forms:
1. a cell that is readily killed by boiling
2. one that is heat resistant

32. Golden Age of Microbiology
Rapid advances by Pasteur and Robert Koch
Discovery of agents of many diseases and role of immunity in prevention and cure of disease
Discoveries include:
Fermentation and pasteurization
Germ theory of disease
Vaccination

33. Fermentation and Pasteurization
Pasteur- why did wine sour?
Believed at time, that converted sugars into alcohol
Yeasts do the work of fermentation
Bacteria cause spoilage
Pasteurization

34. Germ Theory of Disease Pasteur: to fight silkworm disease
Ignaz Semmelweis: Instructed hospital staff to wash hands
Lister: treated surgical wounds with phenol solution
John Snow: Interviewed sick and healthy Londoners during cholera epidemic
Robert Koch

35. Ignaz Semmelweiss encouraged hospital staff to wash their hands
Courtesy of Pfizer, Inc.

36. Robert Koch ( )
Demonstrated that anthrax caused by Bacillus anthracis
Usual means of transmission: resistant endospores
Introduced use of pure culture techniques for handling bacteria in lab
Cultured bacteria on agar
Discovered Mycobacterium tuberculosis – causative agent for tuberculosis
Proved germ theory of disease

37. Vaccination Edward Jenner: Introduced vaccine for smallpox
Inoculate with fluid from cowpox blisters prevented smallpox

38. Modern developments in Microbiology
Bacteriology
Mycology
Parasitology
Immunology
Virology
Recombinant DNA technology

39. Taxonomy

40. Taxonomy Involves three steps: 1. Identification 2. Classification
3. Nomenclature
Objective is to arrange organisms into categories that reflect the similarities of the individuals within the groups 40

41. History Carolus Linnaeus: 1700’s: Two Kingdoms: Plants and Animals
Ernst Haekel: 1866: Kingdom Protista
R.H. Whittaker: 1969: Five Kingdoms
Carl Woese: 1990: Three Domains

42. Taxonomic Hierarchy Species: basic unit
Group of related species: strain
Genus: group of similar species
Family: group of similar genera, ends in - aceae
Order: group of similar families, ends in - ales
Class: group of similar orders, ends in - ia
Phylum: group of similar classes
Kingdom: group of similar Phyla
Domain: group of similar Kingdoms 42

44. Domains of the Living World
Bacteria
Archaea
Eucarya
Bacteria and Archaea look identical
Also both are prokaryotes, however differ in chemical composition and are unrelated 44

46. Eucarya
All members of living world that are not prokaryotes are in domain eukarya
May be single celled or multi-cellular
Always contain true membrane-bound nucleus and other internal organelles
Far more complex than prokaryotes 46

47. Four Kingdoms within Domain Eukarya
Animalia
Multicellular, heterotrophic
Plantae
Protista: many single celled eukaryotes
Ex. Paramecium, algae, protozoa
Fungi
Single celled: yeast
Multicellular: molds and mushrooms 47

48. Bacteria Single-celled prokaryotes
Most have specific shapes: cylindrical, spherical, and spiral
Most have rigid cell walls
Multiply by binary fission
Many move using appendages - 48

49. Archaea Have same size, shape, and appearance as bacteria
Multiply by binary fission and move primarily with flagella
Also have cell walls, but differ from bacteria: no peptidoglycan
Interesting Feature: able to grow in extreme environments 49

50. Identification of Microorganisms
Microscopic examination
Culture characteristics
Biochemical tests
Nucleic Acid Analysis
Serological Tests
Person’s symptoms also play a role 50

51. Classification of Microorganisms
Phenotype: Physical appearance
Genotype: Genes
Development of molecular techniques has made this possible
Bergey’s Manual of Systematic Bacteriology
All known species described here
If properties of newly isolated organism do not agree with any description, considered new organism 51

53. Nomenclature International code for Nomenclature of Bacteria
Uses two-word naming system: Binomial Nomenclature
First name is the Genus, capital
Second name is the species, lower case
Both are italicized
Example: Escherichia coli, or E.coli
Strains; minor differences with in species:
E. coli strain B or E.coli strain K-12 53

54. Nonliving Members of Microbial World
In order to be considered alive, must be composed of one or more cells
Viruses, Viroids, and prions are termed agents
Viruses:
Piece of nucleic acid surrounded by protein coat
Can only multiply inside human host cells
Obligate intercellular parasites - 54

55. Non-living members of the bacterial world
Viroids:
Simpler than viruses
Single short piece of RNA
No protective coat
Can only multiply inside cells
Prions:
Appear to only be protein without nucleic acid
Possible another agent is causing the disease 55