1. Microbiology: A Systems Approach
PowerPoint to accompany
Microbiology: A Systems Approach
Cowan/Talaro
Chapter 1
The Main Themes of Microbiology
Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

2. Chapter 1 Topics Scope of Microbiology Importance of Microorganisms
Characteristics of Microorganisms
History of Microbiology
Taxonomy

3. Scope of Microbiology Immunology
Public health microbiology & epidemiology
Food, dairy and aquatic microbiology
Agricultural microbiology
Biotechnology
Genetic engineering & recombinant DNA technology

4. Importance of Microbiology
First bacteria
Photosynthesis and decomposition
Human use of microorganisms
Infectious diseases

5. Bacteria appeared approximately 3.5 billion years ago.
Fig. 1.1 Evolutionary timeline

6. Microbes are involved in photosynthesis - account for >50% of the earth’s oxygen. Decomposition – nutrient recycling.
Fig. 1.2 Microbial habitats

7. Microbes are used to extract copper from ore, synthesize drugs and enzymes, and bioremediate contaminated water.
Fig. 1.3 Microbes at work

8. The most common infectious diseases worldwide.
Fig. 1.4 Worldwide infectious disease statistics

9. Characteristics of Microorganisms
Procaryotic – no nucleus and organelles
Eucaryotic – nucleus and organelles (mitochondria, etc.)

10. There is a difference between the cell structure of a procaryote and eucaryote. Viruses are neither but are considered particles.
Fig. 1.5 Cell structure

11. There are six main types of microorganisms: 1. ) bacterium, 2
There are six main types of microorganisms: 1.) bacterium, 2.) Fungus, 3.) Algae, 4.) Virus, 5.) Protozoan, 6.) Helminth.
Fig. 1.6 The six types of microorganisms

12. Microorganisms vary in size - 1µm to 200 nm.
Fig. 1.7 The size
of things

13. Microorganisms were first observed by Antonie van Leeuwenhoek, using a primitive microscope.
Fig. 1.9 Leeuwenhoek’s microscope

14. The development of an experimental system that answered questions objectively was called “scientific method”.
Fig The pattern of deductive reasoning

15. Scientific Method Hypothesis Experimentation Results
Conclusion or theory

16. History of Microbiology
Spores and sterilization
Spontaneous generation
Aseptic technique
Germ theory

17. Spores and sterilization
Some microbes in dust and air were resistant to high heat.
Spores were later identified.
The term “sterile” was introduced which meant completely eliminating all life forms from objects or materials.

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

19. Jan Baptista van Helmont’s recipe for mice
Place a dirty shirt or some rags in an open pot or barrel containing a few grains of wheat or some wheat bran, and in 21 days, mice will appear.
There will be adult males and females present, and they will be capable of mating and reproducing more mice.

20. Recipe for bees
Kill a young bull, and bury it in an upright position so that its horns protrude from the ground.
After a month, a swarm of bees will fly out of the corpse.

21. Louis Pasteur showed microbes caused fermentation & spoilage, and disproved spontaneous generation.
Fig Louis Pasteur

22. Pasteur’s Experiment Microbes being destroyed Vigorous heat
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Pasteur’s Experiment
Microbes
being
destroyed
Vigorous heat
is applied.
Broth free of
live cells (sterile)
Neck on second
sterile flask
is broken;
growth occurs.
Neck intact; airborne
microbes are
trapped at base,
and broth is sterile.
(d)

23. Germ theory of disease
Many diseases are caused by the growth of microbes in the body and not by sins, bad character, or poverty, etc.

24. Robert Koch verified the Germ theory (Koch’s postulates).
Fig Robert Koch

25. Semmelwiess and Hand Washing

26. Aseptic technique
Joseph Lister first introduced the technique in order to reduce microbes in a medical setting and prevent wound infections.

27. Taxonomy A system for organizing, classifying & naming living things.
Primary concerns of taxonomy are classification, nomenclature, and identification.

28. Levels of Classification
Domain
Kingdom
Phylum or Division
Class
Order
Family
Genus
species

29. Notice how inclusive a kingdom can be, and how less inclusive a genus and species can be.
Fig Sample taxonomy

30. Domains Developed after the five-kingdom system
Eubacteria -true bacteria, peptidoglycan
Archaea –odd bacteria that live in extreme environments, high salt, heat, etc
Eukarya- have a nucleus, & organelles

31. The Domain system was developed by Dr. Woese
The Domain system was developed by Dr. Woese. The basis of the Domain system is the rRNA sequence information.
Fig Woese system

32. Subdivisions or Kingdoms
Monerans
Fungi
Protists
Plants
Animals

33. The five-kingdom system became the standard until molecular biology techniques were used to develop the Domain system.
Fig Traditional Whittaker system of classification

34. Evolution
Classification schemes allow for a universal tree of life “phylogenetic tree”.
Living things change gradually over millions of years
Changes favoring survival are retained & less beneficial changes are lost.

35. Nomenclature Binomial (scientific) nomenclature
Genus – Bacillus, always capitalized
species - subtilis, lowercase
Both italicized or underlined
Bacillus subtilis (B. subtilis)

36. Identification
The process of discovering and recording the traits (physical, biochemical, genetic) of organisms, thereby, placing them in a taxonomic scheme.