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Biology 220 - Microbiology

Biology 220 - Microbiology. Kathleen Devlin kdevlin@csusb.edu. General Lab Info. Lab Midterm – 100 pts Lab Final – 100 pts Lab Assignments – 32 pts This may include weekly in-lab assignments quizzes Lab Participation – 18 pts 1 pt each week for signing in on time

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Biology 220 - Microbiology

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  1. Biology 220 - Microbiology Kathleen Devlin kdevlin@csusb.edu

  2. General Lab Info • Lab Midterm – 100 pts • Lab Final – 100 pts • Lab Assignments – 32 pts • This may include • weekly in-lab assignments • quizzes • Lab Participation – 18 pts • 1 pt each week for signing in on time • 1 pt each week for proper cleanup

  3. Lab Protocols • Be on time • Read your lab prior to lab • Clean up after yourselves

  4. Biohazard Disposal • Put tubes in tube rack • Put plates, pipet tips, microtubes, etc in biohazard bucket • Put dirty slides in “Dirty Slides” bucket • Put broken glass in “Broken Glass” bucket

  5. Lab Safety • No food or drinks • Clean your lab bench with disinfectant before and after lab • Report any broken glass or injuries immediately • Be aware when using bunsen burners

  6. Exercise 1 - Scavenger Hunt • Objective: Find items commonly used in lab

  7. Exercise 2 – The Unseen Organism • Bacteria and some Fungi are too small to be seen, but are everywhere (ubiquitous) • Objective: Demonstrate that microorganisms exist in the air and on surfaces

  8. Types of Cultures/Media • Broth – liquid • Slant – solid, agar containing tube, dried at an angle • Plate – solid, agar containing petri dish • We will use many types of media throughout the quarter, each having different nutrients/properties

  9. Aseptic Transfers • Movement of bacteria from one media culture to another, without introducing contamination • Tools • Loop • Needle • Flame • Sharpie (label everything!!!)

  10. Aseptic Transfer, cont. • Label the new, sterile media (initials and bacteria being transferred) • Label tube glass or bottom of plates • Hold both tubes in hand not holding inoculating loop/needle • Flame inoculating loop/needle until red hot • Cool ~15 seconds • Remove both caps with little finger • Pass tube opening through flame • Take inoculum from tube and quickly place in/on new medium • Flame tube openings • Recap

  11. Exercise 3 - Culture Transfer Techniques • Objective: Transfer a bacterium from a culture to sterile media without introducing contamination • Each group of 4 students will need: • 2 broth tube • 2 slant tube • 2 agar plate • Transfer Micrococcus luteusbroth to each type of media • Transfer Micrococcus luteusslant to each type of media • Place tubes in incubation rack and plates in tub (always incubate plates upside down!!!!)

  12. Microscopy

  13. Microscope Care • Make sure lenses are clean (w/lens paper) • Store with lowest power objective lens in position • Stage should be all the way down • Turn power off

  14. Tips for Using the Microscope • Always start on the lowest power (4x) • Use course focus to bring object into view • Use fine focus to make the image sharp • Move to the next power • Use only the fine focus from here on out • Before you get to the 100x lens, put a drop of oil on the slide • Use the iris diaphram and light intensity to adjust light levels

  15. Exercise 4 – ID of Cells • Objectives: Recognize visual differences between prokaryotic and eukaryotic cells; Identify three basic morphologies of prokaryotic cells. • Eukaryotic – cells of animals, plants, fungi, and protists. Contain membrane bound organelles • Prokaryotic – cells of bacteria. No membrane bound organelles. 3 basic shapes • Cocci = sphere • Bacilli = rod • Spirilla = spiral

  16. Staphylococcus aureus • Gram-positive, cluster forming (like grapes) cocci • Normally found in nose and on skin • Can cause pneumonia, nosocomial infections, food poisoning, TSS

  17. Bacillus cereus • Gram-positive rod • Causes gastrointestinal intoxication • Found in a wide variety of foods

  18. Treponema pallidum • Spirochaete bacterium • Causes syphilis

  19. Yeast • Eukaryotic • Fungus • Used in making beer, wine, and cheese • Can form symbiotic relationship with bacteria • Note: These cells are round, but we do not use the term “cocci” for eukaryotic cells.

  20. Human Blood Smear • Eukaryotic cell • Note: These cells are round, but we do not use the term “cocci” for eukaryotic cells.

  21. Note the size difference between prokaryotic and eukaryotic cells

  22. Exercise 5 - Motility • Objective: Determine if a bacterium is motile • Some bacteria have the ability to move toward or away from a stimulus • TTC will turn red along the path traveled by the bacterium

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