Microbiology DepartmentFaculty of MedicineUniversity of Brawijaya

The science of classification, especially the classification of living forms, is called taxonomy

The objective of taxonomy is - to classify living organisms – that is , to

establish the relationship between one group of organisms and another and to differentiate between them

Systematics, or phylogeny, is the study of evolutionary history of organisms

From the time of Aristotle:living organisms Plants or Animals

1735, Carolus Linnaeus :Formal system of classification

2 kingdom : Plantae and Animalia

1857, Carl von Nägeli, proposed that bacteria and fungi were placed in the Plant Kingdom

1866, Ernst Haeckel proposed the Kingdom Protista to include bacteria, protozoa, algae, and fungi.

Fungi were placed in their own kingdom in 1959

1937, Edouard Chatton, the term of Prokaryote was introduced to distinguish cells having no nucleus from nucleated cells of plants and animals

1968, Robert G.E.Murray proposed the Kingdom Prokaryotae

1969, Robert H.Whittaker founded the Five Kingdom System in which prokaryotes were placed in the Kingdom Prokaryotae (or Monera), and eukaryotes comprised the other four kingdom

The Three Domains The Kingdom Prokaryotae had been based on

microscopic observations

New techniques in molecular biology revealed that there are actually two types of prokaryotic cells and one type of eukaryotic cell

The discovery of three cell types was based on the observation that ribosome are not the same in all cell

In 1978, Carl R.Woese proposed elevating the three cell types to a level above kingdom, called domain

The Three Domains

1. The Domain Eukarya : animals, plants, fungi and protists

2. The Domain Bacteria : includes all of the pathogenic prokaryotes as well as many of the nonpathogenic prokaryotes found in soil and water

3. The Domain Archaea : includes prokaryotes that do not have peptidoglycan in their cell walls

The Three Domains

The Taxonomy Hierarchy

Similar species are grouped into a genus Similar genera are grouped into a family Families into an order Order into a class Classes into a division or phylum Phyla into a kingdom Kingdoms into a domain

The Taxonomy Hierarchy

DOMAIN : BACTERIA Phylum : PROTEOBACTERIA Class : Gamma-proteobacteria Order : Enterobacteriales Family : Enterobacteriaceae Genus : Escherichia Species : Escherichia coli

Scientific Nomenclature Was established in 1735 by Carolus Linnaeus Every organism is assigned two names, or binomial

binomial nomenclature These names are the genus name and specific epithet

(species) The genus name is always capitalized and always a noun.

The species name is lowercase and is usually an adjective Both names are printed underlined or italicized

Streptococcus pneumoniae Scientific names are to be taken from Latin Suffixes for order and family are – ales and – aceae,

respectively

Classification of Prokaryotes

Prokaryotes, from Greek words meaning prenucleus include both the bacteria and the archaea

Bergey’s Manual of Systematic Bacteriology is the standard reference on bacterial classification

A group of bacteria derived from a single cell is called a strain

Closely related strains constitute a bacterial species

Methods of Classifying and Identifying Microorganisms1. “Bergey’s Manual of Determinative Bacteriology” is the standard

reference for laboratory identification of bacteria2. Morphological characteristics differential staining techniques3. The presence of various enzymes biochemical tests 4. Serological tests serotypes/serovars slide agglutination test,

ELISA, Western blotting5. Phage typing6. Fatty acid profiles7. Flow cytometry measures physical & chemical charact. of cells8. The percentage of GC base pairs in the nucleic acid of cells can be

used in the classification of organisms9. The number and sizes of DNA fragments, or DNA fingerprints10.The sequence of bases in rRNA11.The polymerase chain reaction (PCR)12.Nucleic Acid Hybridization Southern blotting