 MICROBIOLOGY CHAPTER 9 part a
 An Introduction to Taxonomy: the Bacteria
 Microbiology 130
 Roberta Brashear-Kaulfers
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Taxonomy
 Taxonomy: the Science of Classification
 The science of classifying organisms
 Provides universal names for organisms
 Provides a reference for identifying organisms
 Groupings of organisms
 WHY Classify?
 Establish criteria for ID
 Arrange related organisms into groups
 Provide information about evolution of organisms
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Taxonomy
 Systematics or phylogeny: The study of the
evolutionary history of organisms.
 All Species Inventory is underway (2001-2025)
 To identify all species of life on Earth
 Linnaeus – (1707-1778)Father of modern taxonomy
 Created Binomial nomenclature
 2 names- Genus-species
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Levels of Classification
 Kingdom
 Division/Phyta/Phylum
 SubPhylum
 Class
 Order
 Family
 Genus
 Species/Specific Epithet
 Subspecies/Strain
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Dichotomous Key- to Identify Bacteria
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Taxonomy
 1735
Plant and Animal Kingdoms
 1857
Bacteria and fungi put in the Plant Kingdom
 1866
Kingdom Protista proposed for bacteria, protozoa,
algae, and 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
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5 Kingdom System or 6 Kingdom System
 Kingdom Monera -
Prokarya -
Eubacteria - new bacteria -
Archaebacteria – old bacteria
 Kingdom Protista- 1 celled organisms- Eukarya
 Kingdom Fungi- multicellular fungi/yeast- Eukarya
 Kingdom Plantae- photosynthetic plants- Eukarya
 Kingdom Animalia- animals from zygote- Eukarya
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The Three-Domain System
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Table 10.1
The Three-Domain System
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Figure 10.1
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Table 10.2
Endosymbiotic Theory
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Figures 10.2, 10.3
Scientific Names
of Genus
Source of
Scientific Binomial Source
Name
Specific Epithet
Klebsiella 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
Chains of cells
Forms pus (pyo-)
pyogenes
(strepto-)
Penicillium
chrysogenum
Tuftlike (penicill-)
Produces a yellow
(chryso-) pigment
Trypanosoma cruzi
Corkscrew-like
(trypano-, borer;
soma-, body)
Honors Oswaldo
Cruz
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Taxonomic Hierarchy
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Figure 10.5
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
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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
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Prokaryotes
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Figure 10.6
The Tree of Life is replaced by a Shrub
 Universal ancestor- unlikely
 Broke into 2 lines –Bacteria and Archae
 Still not correct, both share similar genes
 Some organisms have genes from all 3 Domains
 “Shrub of Life” theory - lateral gene swapping
 Archae made of :
 - Methanogens - Extreme halophiles Extreme thermoacidophiles- have extremozymes at 80*
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Classification of Viruses
 Acellular infectious agents
 DNA and protein coat
 Classified by chemical and physical characteristics
 Shape, Symmetry of protein coat
 Presence of envelope, Enzymes and/or tail,
 Virology- study of viruses is important because:
 1) recognized branch of Microbiology
 2) Concern to health scientists. Many cause diseases
in humans, animals, plants and other microbes
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References
Bergey’s Manual of Determinative
Bacteriology
Morphology, differential
staining, biochemical tests
Provides identification schemes for
identifying bacteria and archaea
Bergey’s Manual of Systematic
Bacteriology
Based on rRNA sequencing
Provides phylogenetic information on
bacteria and archaea
Approved Lists of Bacterial Names
Lists species of known prokaryotes
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Based on published articles
Identification Methods
 Morphological
characteristics: Useful
for identifying
eukaryotes
 Differential staining:
Gram staining, acidfast staining
 Biochemical tests:
Determines presence
of bacterial enzymes
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Figure 10.8
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Phage Typing
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Serology
Combine known
antiserum plus
unknown
bacterium
Slide
agglutination
ELISA
Western blot
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