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Taxonomy of Cognitive Educational Objectives. The taxonomy is hierarchical: 1. Knowledge – ability to recall previousl

Taxonomy of Cognitive Educational Objectives. The taxonomy is hierarchical: 1. Knowledge – ability to recall previously learned material. 2. Comprehension - ability to grasp the meaning of the material; ability to explain, summarize, predict consequences.

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Taxonomy of Cognitive Educational Objectives. The taxonomy is hierarchical: 1. Knowledge – ability to recall previousl

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  1. Taxonomy of Cognitive Educational Objectives. The taxonomy is hierarchical: 1. Knowledge – ability to recall previously learned material. 2. Comprehension - ability to grasp the meaning of the material; ability to explain, summarize, predict consequences. 3. Application – ability to use material in new situations. 4. Analysis – ability to break down material into component parts, recognize organizing principles. 5. Synthesis – ability to put parts together to form a new whole. 6. Evaluation – ability to judge the value of material based on definite criteria. Knowledge is the lowest level of learning; Evaluation is the highest

  2. 1. Method 2. Hypothesis 3. Testable predictions 4. Skepticism 5. Progressive enterprise: Verification/Falsifiability 6. Destination/Journey

  3. Science moves forward as much by critiquing the conclusions of others, as by making novel discoveries Stephen J. Gould

  4. Overview of Chemotaxis

  5. Stimulus - Response • Environmental stimuli • Signal receiver • Signal sensor (Kinase) • Phospho-relay • Response regulator (RR) • Response

  6. Sensor (Kinase) Response Regulator (RR) Two-component Signaling

  7. Pfeffer assay

  8. Chemotatic response of Salmonella 10 mM L-serine 10 mM phenol Rubik et al, PNAS 75:2820-4, 1978

  9. Tracks of swimming bacteria

  10. Swimming bacteria • http://www.rowland.org/labs/bacteria/showmovie.php?mov=swimming_ecoli

  11. Darkfield movie of motile E. coli http://www.fbs.osaka-u.ac.jp/labs/namba/npn/index.html

  12. Tumbling Running

  13. Swimming bacteria • http://www.rowland.org/labs/bacteria/showmovie.php?mov=fluo_fil_leave

  14. Namba movies 1, 5 Building a flagellum without from within Driving the motor with PMF

  15. Organization of flagellar genes of S. typhimurium into five clusters

  16. EnvZ kinase OmpR~P Glucose Osmolarity Heat Shock

  17. Tracks of swimming bacteria

  18. A matter of tumble frequency

  19. Stimulus - Response • Environmental stimuli • Signal receiver • Signal sensor (Kinase) • Phospho-relay • Response regulator (RR) • Response

  20. The chemotaxis signaling pathway in E. coli/Salmonella

  21. Different types of chemotaxis receptors: they are clustered at one or the other pole

  22. Cryo-tomography

  23. MCP (methyl accepting chemotaxis proteins)

  24. Chemotactic two-component system Excitation Tumbling OM CM CM OM Kinase activation CW ATP ADP M CheY Repellents CheA CheW P MCP P Smooth Swimming OM CM CM OM CCW Kinase inhbition M CheY CheA Attractants CheW MCP Macnab R. M. Annu. Rev. Microbiol. 2003

  25. Adaptation OM CheR CM OM CM ATP ADP +CH3 M CheY CheA CheW -CH3 P P CheZ P CheB P

  26. Sequential activation and adaptation (via methylation) of a chemoreceptor

  27. Hazelbauer et al 2008

  28. Phenotypes of che mutants OM CheR CM OM CM ATP ADP Repellents +CH3 M CheY CheA CheW -CH3 P P Attractants CheZ P CheB P

  29. Plate assay for chemotaxis

  30. Phenotypes of che mutants∆cheA, ∆cheY OM CheR CM OM CM CCW ATP ADP Repellents +CH3 M CheW -CH3 Attractants CheZ CheB Smooth Swimming

  31. Phenotypes of che mutants∆cheR OM CM OM CM CCW ATP ADP Repellents +CH3 M CheY CheA CheW -CH3 Attractants CheZ CheB Smooth Swimming

  32. Phenotypes of che mutants∆cheB, ∆cheZ OM CheR CM OM CM CW ATP ADP Repellents +CH3 M CheY CheA CheW -CH3 P P Attractants Tumbling

  33. Summary • Bacteria move by rotating flagella • CW: tumbling; CCW: running • Chemotaxis pathway • MCPs: receive the chemical signals • CheA: sensor, kinase; • CheR: methylation; CheB: demethylation • CheY: RR, interacts with flagella motor • CheY+P: CW; CheY-P: CCW • CheZ: dephosphorylation • Phenotypes of ∆che mutants • ∆cheA,Y,R: smooth swimming; ∆cheB,Z: tumbling

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