1. Classification of Microorganisms
Chapter 10
Classification of Microorganisms

2. Taxonomy Taxonomy The science of classifying organisms
Provides universal names for organisms
Provides a reference for identifying organisms

3. Taxonomy Systematics or phylogeny
The study of the evolutionary history of organisms
All Species Inventory ( )
To identify all species of life on Earth

4. Taxonomy 1735 Plant and Animal Kingdoms
1857 Bacteria & fungi put in the Plant Kingdom
1866 Kingdom Protista proposed for bacteria, protozoa, algae, & fungi
1937 "Prokaryote" introduced for cells "without a nucleus"
1961 Prokaryote defined as cells in which nucleoplasm is not surrounded by a nuclear membrane
1959 Kingdom Fungi
1968 Kingdom Prokaryotae proposed
1978 Two types of prokaryotic cells found

5. The Three-Domain System
Table 10.1

6. The Three-Domain System
Figure 10.1

7. Table 10.2

8. Endosymbiotic Theory
Figure 10.2
Figure 10.3

9. Be able to use proper scientific (binomial) nomenclature.
Source of Genus name
Source of Specific epithet
Kbebsiella pneumoniae
Honors Edwin Klebs
The disease
Pfiesteria piscicida
Honors Lois Pfiester
Disease in fish
Salmonella typhimurium
Honors Daniel Salmon
Stupor (typh-) in mice (muri-)
Streptococcus pyogenes
Chains of cells (strepto-)
Forms pus (pyo-)
Penicillium notatum
Tuftlike (penicill-)
Spores spread in wind (nota)
Trypanosoma cruzi
Corkscrew-like (trypano-, borer; soma-body)
Honors Oswaldo Cruz

10. Taxonomic Hierarchy
4.  Can a species be identified by cell morphology alone?
5.  Can a Grams stain specifically identify an organism?
6.  At what taxonomic level is a Grams stain useful?
7.  At what taxonomic level are biochemical tests useful?
Figure 10.5

11. Species Definition Eukaryotic species:
A group of closely related organisms that breed among themselves
Prokaryotic species:
A population of cells with similar characteristics
Clone: Population of cells derived from a single cell
Strain: Genetically different cells within a clone
Viral species:
Population of viruses with similar characteristics that occupies a particular ecological niche

12. Domain Eukarya
Animalia: Multicellular; no cell walls; chemoheterotrophic
Plantae: Multicellular; cellulose cell walls; usually photoautotrophic
Fungi: Chemoheterotrophic; unicellular or multicellular; cell walls of chitin; develop from spores or hyphal fragments
Protista: A catchall for eukaryotic organisms that do not fit other kingdoms

13. Prokaryotes
Figure 10.6

14. 2. How does classification differ from identification of microorganisms?
3.   How is morphology used to identify a species?

15. Classification vs Identification
Figure 10.5

16. References • Bergey’s Manual of Determinative Bacteriology
Provides identification schemes for identifying bacteria and archaea
Morphology, differential staining, biochemical tests
• Bergey’s Manual of Systematic Bacteriology
Provides phylogenetic information on bacteria and archaea
Based on rRNA sequencing
• Approved Lists of Bacterial Names
Lists species of known prokaryotes
Based on published articles

17. Identification Methods
Morphological characteristics: Useful for identifying eukaryotes
Differential staining: Gram staining, acid-fast staining
Biochemical tests: Determines presence of bacterial enzymes
9.  On what kinds of characteristics do selective/differential media capitalize?
Figure 10.8

18. Figure 10.7

19. Numerical Identification
8.  How does a rapid identification system work?
Figure 10.9

20. 10. From what is antisera produced?
11. How does a slide agglutination test work?

21. Serology Combine known antiserum + unknown bacterium
Slide agglutination
ELISA
Western blot
13.  Compare and contrast the Western blot test and the Southern blot test.
Figure 10.10

22. Western Blot
Figure 10.12

23. Phage Typing 12. What is phage typing?
How does a particular phage affect a susceptible host?
Figure 10.13

24. Flow Cytometry Uses
Differences in electrical conductivity between species
Fluorescence of some species
Cells selectively stained with antibody + fluorescent dye
Figure 18.11

25. 14.  How does the G+C content of a cell help its identification?
15.  What is the principle behind DNA fingerprinting?

26. Genetics DNA base composition Guanine + cytosine moles% (GC)
DNA fingerprinting
Electrophoresis of restriction enzyme digests
rRNA sequencing
Polymerase Chain Reaction (PCR)
Figure 10.14

27. 16.  How does nucleic acid hybridization help relate two organisms?
How does it relate to DNA “chips”

28. Nucleic Acid Hybridization
Figure 10.15

29. Nucleic Acid Hybridization: DNA probe
Figure 10.16

30. Nucleic Acid Hybridization: DNA chip
Figure 10.17

31. Dichotomous Key
17.  Understand the use and principles of dichotomous keys and Bergey’s Manual.

32. Cladogram
Figure

33. Cladogram
Figure