NAS 161: Lab Practical 2 Review

1. NAS 161: Lab Practical 2 Review

2. Streaking Technique What Why? 1. Flame Loop and Wire (R hand), cool slightly 2. Pick up broth (pure vs. mixed culture) with L hand, hold at angle, open with R pinkie, flame opening 3. Dip loop, re-flame opening and re-cap 4. Lift petri dish lid slightly, streak 1/3 (area 1) 5. Flame loop, run across area 1 and streak area 2 6. Flame loop, run across area 2 and streak area 3 7. Turn upside down, label bottom and incubate! (37o) What is the point of all this streaking !?!

3. What are we streaking on?... Culture Media: Nutrient material designed for growth of microorganisms Two main types (for the purpose of this exam): Selective: Selects for the growth of certain organisms while inhibiting the growth of others Allows for many bacterial types to grow, but differentiates between them based on how they affect the media (color change, etc.) Differential:

4. Media Types Classification Type Characteristics (selective, differential, both, neither) Tasty “all-purpose” bacteria food grows a wide variety of microbes Neither Nutrient Used to differentiate various species of streptococci according to hemolytic activity Differential b hemolysis – complete, clear area around bacteria a hemolysis – incomplete, greenish tinge g hemolysis – no hemolysis Blood Agar (TSA with blood)

5. Media Types Classification Type Characteristics (selective, differential, both, neither) Selective – high salt concentration selects for Staphylococcus, inhibits most others Both Differential – differentiates pathogenic staph (ferment mannitol, turn media yellow) from non-pathogenic Mannitol Salt Selective – inhibits Gram +, selects for only Gram – Both Differential – Lactose fermenters show colonies with dark centers and clear borders. Non-lactose fermenters are colorless EMB

6. Media Types Classification Type Characteristics (selective, differential, both, neither) Contains hemoglobin solution and supplemental ingredients that are required by some fastidious (hard to grow/picky) organisms like Neisseria and Haemophilus Neither Chocolate Agar Selective – designed to grow Gram (-) enteric (= intestinal) rods Differential – wire with single bacterium innoculated through every compartment. Pattern of enzymatic activity distinguishes organism Enterotube

7. Media Types Lowenstein Jensen media Used to grow Mycobacteria species

8. Identifying Bacterial Junk Shape Arrangement Diplococci Spirilla Streptococci Staphylococci Bacilli Cocci

9. Other Bacterial Cell Structures Capsules Endospores Flagella

10. The Gram Stain A differential staining method to visually identify gram (+) and gram (-) organisms Purpose: Steps: 1. Prepare a smear: add bacteria/water to slide, dry, flame (fixation) 2. Primary Stain: Crystal violet (stains purple) 3. Mordent: Iodine, forms large complex with crystal violet 4. Decolorizing agent: Alcohol, washes dye out of gram (-) cells 5. Counterstain: Safranin (stains pink) What kind of cell walls do these organisms have?

11. Antibiotic Sensitivity Test Be able to interpret results

12. Disinfectants Isopropyl Alcohol Least effective (evaporation too fast ) Results in this lab this year. Not necessarily absolute indication of effectiveness Second least effective Iodine Lysol Most effective against Staph Most effective against E. coli Bleach Don’t memorize this. Be able to interpret results in a petri dish. More mm of inhibition = better disinfectant

13. Physical Methods of Microbial Control Know functions, advantages, limits 1. Autoclave Moist Heat (pressurized steam): Efficient sterilization, steam must contact all surfaces, including insides of containers 2. Oven Dry Heat: sterilizes powders, oils or objects that would be damaged by water. Requires higher time and temp. 3. UV radiation DNA damage: Forms thymine dimers, used to sterilize surfaces in O.R.’s, nurseries, etc. Does not penetrate far into tissue, does not pass through solid covering, may damage eyes and cause cancer 4. Filtration Physical removal of microbes: Media suctioned through thin screen. Can be used to clean air, does not kill bacteria

14. Mycology Vocab Saprophytes Parasites Hyphae Mycelium Mycosis (mycoses) Yeast Mold Diphasic Aseptate (coenocytic)

15. Phycomycetes Zygomycetes Rhizopus Asexual reproduction Sexual Reproduction sporangia zygospore sporangiophore contains sporangiospores gametes

16. Ascomycetes Peziza Sexual Reproduction ascus, ascospores

17. Ascomycetes Asexual Reproduction 3. Saccharomyces cerevisiae 1. Penicillium conidia conidiophores 2. Aspergillus aflatoxin, aspergillosis Budding

18. Basidiomycetes 1. Amanita Scales (universal veil remnants) Gills Ring (partial veil remnants) Stalk Cup Capsule 2. Cryptococcus neoformans

19. Basidiomycetes Basidiospores Mushroom Gill Section Basidium Sexual Reproduction

20. Candida Chlamydospores

21. Parasites Vocabulary Definitive Host Intermediate Host Reservoir Host Vector Direct Life Cycle Indirect Life Cycle Endoparasites Ectoparasites Adult Larvae Trophozoite Cyst

22. Giardia lamblia

23. Trichomonas vaginalis

24. Trypanosoma gambiense

25. Entamoeba histolytica

26. Plasmodium Know Life Cycle*

27. Toxoplasma gondii

28. Tapeworms (flatworms) Know Life Cycle*

29. Schistosoma (fluke)(flatworm) Know Life Cycle*

30. Ascaris (roundworm) Know Life Cycle*

31. Enterobius vermicularis (pinworm) (roundworm)

32. Trichinella Spiralis (roundworm)

33. Ancyclostoma/Necator (hookworms) (roundworm)

34. Wuchereria bancrofti (filariasis) (roundworm) Elephantiasis

35. Arthropod Vectors Flea Louse (Lice)

36. Arthropod Vectors Tick Mite