1. Dr. Yoga Sundram DVM., MS., PhD. South Georgia College

2. The main themes of Microbiology 2

3.  Microbiology is the study of organisms too small to be seen with the naked eye. A microscope is needed to view them.  Microorganisms include: bacteria viruses fungi protozoa helminths (worms) algae 3

4.  Immunology  Public health microbiology and epidemiology  Food, dairy and aquatic microbiology  Biotechnology  Genetic engineering and recombinant DNA technology 4

5.  Nutrient production and energy flow  Decomposition  Biotechnology  Genetic engineering  Bioremediation  Infectious disease 5

6.  Nearly 2,000 different microbes cause diseases.  10 B new infections/year worldwide  13 M deaths from infections/year worldwide 6

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8.  Procaryotes and eukaryotes  Procaryotes – Microscopic, unicellular organisms. Lack nuclei and membrane-bound organelles  Eucaryotes – Unicellular and multicellular organisms. Have nuclei and membrane-bound organelles  Viruses Acellular, parasitic particles composed of a nucleic acid and protein 8

9. 9 Insert figure 1.5 basic cell and virus structures

10.  Procaryotes are measured in micrometers.  Viruses in nanometers  Helminths are measured in millimeters. 10

11. 11 Insert figure 1.7 measurements

12.  300 years of contributions by many  Prominent discoveries include: ◦ microscopy ◦ scientific method ◦ development of medical microbiology ◦ microbiology techniques 12

13.  Dutch linen merchant  First to observe living microbes  Single-lens magnified up to 300X 13 Insert figure 1.8

14. 14 Insert figure 1.9 (a) microscope

15. Early belief that some forms of life could arise from vital forces present in nonliving or decomposing matter (flies from manure, etc)

16.  A general approach to explain a natural phenomenon  Form a hypothesis - a tentative explanation that can be supported or refuted by observation and experimentation  A lengthy process of experimentation, analysis and testing either supports or refutes the hypothesis. 16

17.  Results must be published and repeated by other investigators.  If hypothesis is supported by a growing body of evidence and survives rigorous scrutiny, it moves to the next level of confidence - it becomes a theory.  If evidence of a theory is so compelling that the next level of confidence is reached - it becomes a Law or principle. 17

18.  John Tyndall and Ferdinand Cohn each demonstrated the presence of heat resistant forms of some microbes. *Cohn determined these forms to be endospores.  Sterility requires the elimination of all life forms including endospores and viruses. 18

19.  Dr. Oliver Wendell Holmes – observed that mothers of home births had fewer infections than those who gave birth in hospital  Dr. Ignaz Semmelweis – correlated infections with physicians coming directly from autopsy room to maternity ward  Nosocomial Infections - infections acquired during stay in hospitals 19

20.  Joseph Lister – introduced aseptic techniques reducing microbes in medical settings to prevent infections ◦ involved disinfection of hands using chemicals prior to surgery ◦ use of heat for sterilization 20

21.  Many diseases are caused by the growth of microbes in the body and not by sins, bad character, or poverty, etc.  Two major contributors: Louis Pasteur and Robert Koch 21

22.  Showed microbes caused fermentation and spoilage  Disproved spontaneous generation of microorganisms  Developed pasteurization  Demonstrated what is now known as Germ Theory of Disease  Developed a rabies vaccine 22 Insert figure 1.11

23.  Established Koch’s postulates - a sequence of experimental steps that verified the germ theory  Identified cause of anthrax, TB, and cholera  Developed pure culture methods 23 Insert figure 1.12

24.  Formal system originated by Carl von Linné (1701-1778)  Concerned with: ◦ classification – orderly arrangement of organisms into groups ◦ nomenclature – assigning names ◦ identification – discovering and recording traits of organisms for placement into taxonomic schemes 24

25. Domain - Archaea, Bacteria & Eukarya Kingdom Phylum Class Order Family Genus species 25

26.  Binomial (scientific) nomenclature  Gives each microbe 2 names: ◦ Genus - noun, always capitalized ◦ species - adjective, lowercase  Both italicized or underlined ◦ Staphylococcus aureus (S. aureus) ◦ Bacillus subtilis(B. subtilis) ◦ Escherichia coli(E. coli) 26

27.  Changes favoring survival are retained and less beneficial changes are lost.  All new species originate from preexisting species.  Closely related organism have similar features because they evolved from common ancestral forms.  Evolution usually progresses toward greater complexity. 27

28.  Bacteria - true bacteria, peptidoglycan  Archaea - odd bacteria that live in extreme environments, high salt, heat, etc.  Eukarya- have a nucleus and organelles 28

29. 29 Insert figure 1.15 Woese-Fox System