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Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings PowerPoint ® Lecture Slide Presentation prepared by Christine L. Case Microbiology.

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Presentation on theme: "Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings PowerPoint ® Lecture Slide Presentation prepared by Christine L. Case Microbiology."— Presentation transcript:

1 Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings PowerPoint ® Lecture Slide Presentation prepared by Christine L. Case Microbiology B.E Pruitt & Jane J. Stein AN INTRODUCTION EIGHTH EDITION TORTORA FUNKE CASE Chapter 10 Classification of Microorganisms

2 Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Taxonomy The science of classifying organisms Provides universal names for organisms Provides a reference for identifying organisms Goal of showing relationships among organisms Taxon Taxonomic categories to show similarities among organisms Learning objectives: Define taxonomy, taxon, and phylogeny Discuss the limitations of a 2-kingdom classification system.

3 Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Taxonomy Systematics or phylogeny The study of the evolutionary history of organisms and their relationships All Species Inventory (2001-2025) To identify all species of life on Earth Two-kingdom system not based upon natural classification based upon ancestral relationships (e.g., DNA sequencing places fungi closer to animals than plants)

4 Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Taxonomy History 1735Plant and Animal Kingdoms 1857Bacteria & fungi put in the Plant Kingdom 1866Kingdom Protista proposed for bacteria, protozoa, algae, & fungi 1937"Prokaryote" introduced for cells "without a nucleus" 1961Prokaryote defined as cells in which nucleoplasm is not surrounded by a nuclear membrane 1959Kingdom Fungi 1968Kingdom Prokaryotae proposed 1969Organisms divided into five kingdoms 1978Two types of prokaryotic cells found

5 Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings The Three-Domain System Table 10.1 Learning objectives: List characteristics of 3-domain system Classified by cell type, cell wall, rRNA, membrane lipid structure, tRNA, sensitivity to antibiotics A domain can be divided into kingdoms

6 Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings The Three-Domain System Figure 10.1 3-domain recognizes 3 types of cells. Eukarya includes Kingdoms Fungi, Plantae, and Animalia, plus certain protists PeptidoglycanUnusual cell walls

7 Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Table 10.2 Organisms grouped into taxa by phylogenetic relationships Some eukaryotic relationships obtained from fossil records Prokaryotic relationships determined by rRNA sequencing Phylogenetic Hierarchy

8 Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Endosymbiotic Theory Figure 10.3 Figure 10.2 Mutualistic symbiosis between eukaryotic host and bacterium – possible precursor to reproductive capability as a unit Similarities in rRNA sequences supporting endosymbiotic theory

9 Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Scientific Names Scientific binomialSource of Genus name Source of Specific epithet Kbebsiella pneumoniaeHonors Edwin KlebsThe disease Pfiesteria piscicidaHonors Lois PfiesterDisease in fish Salmonella typhimuriumHonors Daniel SalmonStupor (typh-) in mice (muri-) Streptococcus pyogenesChains of cells (strepto-)Forms pus (pyo-) Penicillium notatumTuftlike (penicill-)Spores spread in wind (nota) Trypanosoma cruziCorkscrew-like (trypano-, borer; soma-body) Honors Oswaldo Cruz Learning objectives: Explain why scientific names are used. Binomials (Genus Species) used by scientists worldwide which enables them to share knowledge efficiently and accurately

10 Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Taxonomic Hierarchy Figure 10.5 Learning objectives: List the major taxa. Differentiate between culture, clone, and strain. Similar species are grouped into a genus; similar genera are grouped into a family, etc. KidsKingdom PreferPhylum/ Division CheeseClass OverOrder Fried Family Green Genus SpinachSpecies

11 Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Species Definition Eukaryotic species: A group of closely related organisms that breed among themselves Prokaryotic species: A population of cells with similar characteristics Culture: bacteria grown at a give time in media 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 Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings 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; currently being assigned to kingdoms Viruses not placed in a kingdom (must have host) Domain Eukarya Learning objectives: List the major characteristics used to differentiate the three kingdoms of multicellular Eukarya. Define protist.

13 Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Prokaryotes Figure 10.6 Phylogenetic relationships of prokaryotes (Kingdom – Phylum)

14 Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings References Bergey’s Manual of Determinative Bacteriology (for lab identification) Provides identification schemes for identifying bacteria and archaea Morphology, differential staining, biochemical tests, cell wall composition, oxygen requirements (treatment) 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 Learning objectives: Compare/contrast classification and identification Explain purpose of Bergey’s Manual

15 Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Learning objectives: Describe how staining and biochemical tests are used to identify bacteria

16 Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Methods to Classify and Identify Microbes Morphological characteristics (aided by staining) Presence of certain enzymes Serological tests (antigen – antibody response) Phage typing (susceptibility of bacteria to phages) Fatty acid profiles Flow cytometry Percentage of G-C pairs in nucleic acid Number and sizes of DNA fragments (fingerprints) produced by restriction enzymes Sequence of bases in rRNA Polymerase chain reaction (PCR) to detect DNA

17 Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Identification Methods Morphological characteristics: Useful for identifying eukaryotes Differential staining: Gram staining, acid-fast staining Biochemical tests: Determines presence of bacterial enzymes Figure 10.8 Using metabolic characteristics to identify selected genera of enteric (intestinal) bacteria

18 Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Morphology and differential staining important to proper treatment for microbial diseases

19 Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Numerical Identification Figure 10.9 Rapid identification tools for groups of medically important bacteria (e.g., enterics) are designed to perform several biochemical tests simultaneously. The value for each positive test is circled and compared to a computerized listing. In this case a confirma- tory test is advised.

20 Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Combine known antiserum + unknown bacterium Slide agglutination ELISA (enzyme- linked immunosorbent assay) Western blot Serology Figure 10.10 Learning objectives: Differentiate Western blotting from Southern blotting. Explain how serological tests and phage typing can be used to identify an unknown bacterium. Left grainy appearance is positive for agglutination – bacteria was mixed with antibodies produced in response to same strain

21 Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Western Blot Figure 10.12 Proteins separated by electrophoresis can be detected by their reactions with antibodies

22 Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Phage Typing Figure 10.13 Determining which phages a bacterium is susceptible to: The tested strain was grown over entire plate; known phages are placed in different squares; plaques (areas of lysis) appear dark indicating sensitivity to a specific phage

23 Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Used to identify bacteria in a sample without culturing the bacteria Differences in electrical conductivity between species Fluorescence of some species Cells selectively stained with antibody + fluorescent dye Flow Cytometry Uses Figure 18.11

24 Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings DNA base composition Guanine + cytosine moles% (GC) DNA fingerprinting Electrophoresis of restriction enzyme digests rRNA sequencing Polymerase Chain Reaction (PCR) Genetics Figure 10.14 Learning objectives: Describe how newly discovered microbe can be classified by: DNA base composition, rRNA sequencing, DNA fingerprinting, PCR, and nucleic acid hybridization Plasmids from 7 different bacteria digested with same restriction enzyme: none of these bacteria happen to be identical (source of hospital-acquired infections).

25 Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Nucleic Acid Hybridization Figure 10.15 Greater degree of hybridization (pairing of two strands of DNA, each from a different microbe) indicates greater similarity

26 Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Nucleic Acid Hybridization: DNA probe Figure 10.16

27 Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Nucleic Acid Hybridization: DNA chip Figure 10.17

28 Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Dichotomous Key Learning objectives: Differentiate a dichotomous key from a cladogram. Dichotomous key: successive questions with two possible answers.

29 Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Cladogram Figure 10.18.1 Cladogram: Maps showing evolutionary relationships among organisms.

30 Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Cladogram Figure 10.18.2

31 Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 10.5


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