Ch 10 Classification of Microorganisms Student Learning Outcomes

Ch 10 Classification of Microorganisms Student Learning Outcomes Define taxonomy and phylogeny List some characteristics of 3 domains Differentiate among eukaryotic, prokaryotic, and viral species Explain scientific naming Differentiate between culture, clone, and strain

Compare and contrast classification and identification. Explain the purpose of Bergeys Manual. Describe how staining and biochemical tests are used to identify bacteria. Explain how serological tests can be used to identify an unknown bacterium. Describe how a newly discovered microbe can be classified by various genetic tests. For Dichotomous key application and explanation, see lab Taxonomy vs. Phylogeny

Taxonmoy: Science of classifying organisms. Provides universal names for organisms. Taxonomic categories: Taxon / Taxa Phylogeny or Systematics: Based on evolutionary history of group of organisms. Taxonomic hierarchy shows phylogenetic (evolutionary), relationships among organisms. 1969: Living organisms divided into five kingdoms. 1978: Two types of prokaryotic cells found. Prokaryotic

relationships determined by rRNA sequencing. Domains! The Three-Domain System Foundation Fig 10.1 Level Above Kindom: The Three-Domain System Carl Woese

1978 Endosymbiotic Theory: Origin of Eukaryotes Scientific Nomenclature Common names Vary with languages Vary with geography Binomial Nomenclature: __________+ _______________ Used worldwide

Examples: ? Classification: Species Definition 1. Eukaryotic species: Interbreeding organisms 2. Prokaryotic species: A population of cells with similar characteristics (Bergeys Manual of Systematic Bacteriology is standard reference on bacterial classification). Culture: Bacteria grown in laboratory media Clone: Population of cells derived from a single cell

Strain: Genetically different cells within a clone or species 3. Viral species: Population of viruses with similar characteristics occupying a particular ecological niche. Viruses not placed in kingdom or domain why not? Classification and Identification Fig 10.8 Classification: Placing organisms in groups of related species. Lists of characteristics of known organisms.

Identification: Matching characteristics of an unknown to lists of known organisms. David Hendricks Bergey, 1870 - 1937 Bergeys Manual: Classifying and Identifying Prokaryotes Bergeys Manual of Determinative Bacteriology Morphology, differential

Provides identification staining, biochemical schemes for identifying tests eubacteria and archaebacteria Bergeys Manual of Systematic Bacteriology Provides phylogenetic information on eu- and archaebacteria

Based on rRNA sequencing Clinical Lab Identification Morphological characteristics only useful for identifying eukaryotes. Numerical Rapid Identification Differential stains: ____________ ____________

Biochemical tests: Determine presence of ____________ Serological Testing - Serology Involves reactions of microorganisms with specific _____________: Combine known antiserum with unknown

bacterium Useful in determining the identity of species AND strains. Examples: Slide agglutination ELISA (see lab) Western blot (see later) Fig 10.10

Genetics DNA Fingerprinting Nucleic Acid Amplification Tests use Polymerase chain reaction (PCR). Small amount of microbial DNA in a sample is amplified. The presence or identification of an organism is indicated by amplified DNA. (see lab) Fig. 10.10

Nucleic Acid Hybridization: ssDNA or RNA from related organisms will hydrogen-bond to form a ds molecule. Application: DNA chips Ribotyping and rRNA sequencing Whole Genome Sequencing (WGS) Fig 10.17 The E