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1 E nhancement of A nalytical T hinking through S cientific I nvestigations Instructor: Ann S N Lau Lesson 8.

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Presentation on theme: "1 E nhancement of A nalytical T hinking through S cientific I nvestigations Instructor: Ann S N Lau Lesson 8."— Presentation transcript:

1 1 E nhancement of A nalytical T hinking through S cientific I nvestigations Instructor: Ann S N Lau Lesson 8

2 2 Microorganisms http://www.thinkgeek.com/geektoys/plush/6708/zoom/

3 3 Microorganisms The oldest form of life on earth Sometimes called “microbes”, especially the disease-causing species Small in size, barely be seen by naked eyes, requires the use of microscope for investigation Found in environment, food, industrial, medical; beneficial or harmful Unicellular or multicellular

4 4 Microorganisms Living requirement Water Substratum (sometimes) Nutrient (they recycle nutrient by acting as decomposers)

5 5 Classification Unicellular or multicellular Examples - Bacteria (unicellular) Fungi (e.g. yeast) (unicellular or multicellular) Protist (e.g. one-celled algae: diatom, slime- mold, etc.)

6 6 Bacteria E.coli, Bacillus, Cynobacteria (Photosynthetic), Streptococcus 鏈球菌, Staphylococcus 葡萄球菌 Small in size (micrometers 10 -6 ) Can grow anywhere, reproduce by binary fission or budding Cell wall, lack of organelles, no define nucleus Cynobacteria http://en.wikipedia.org/wiki/Microorganism http://en.wikipedia.org/wiki/Bacteria Staphylococcus E.coli http://en.wikipedia.org/wiki/Microorganism

7 7 Fungus Saccharomyces cerevisiae, Candida species, Penicillium, Aspergillus species (bread mold), mold species that cause athletes foot etc. Can be beneficial or harmful Use in food industry, but some species can cause food to deteriorate http://en.wikipedia.org/wiki/Yeast Candida albicans Aspergillus niger http://en.wikipedia.org/wiki/Aspergillus

8 8 Protist Slime mold, diatom 矽藻 May be able to have slight movement http://en.wikipedia.org/wiki/Slime_mold http://en.wikipedia.org/wiki/Diatoms

9 9 Microorganisms Environment Bacteria – nitrogen cycle and carbon cycle Waste water treatment

10 10 Microorganisms Food industry Alcoholic beverage (wine fermentation), soda, root beer, bread baking, xylitol production Probiotic supplement 益生菌 http://en.wikipedia.org/wiki/Xylitol Xylitol crystal

11 11 Microorganisms Biotechnology  Short life-cycle with simple genome  Good study model in biotechnology  Used in gene cloning, recombinant protein and DNA technology  Production of insulin, growth hormone, etc.  Genetics studies

12 12 Microorganisms Beneficial or Harmful ??

13 13 Microorganisms Beneficial Food production Antibiotics production Alcoholic fermentation Bakery

14 14 Microorganisms Pathogenic 致病的 cholera 霍亂 syphilis 梅毒 anthrax 炭疽 leprosy 痲瘋 tuberculosis 結核病 Plaque (Black Death) Normally cause infection http://en.wikipedia.org/wiki/Bacteria Anthrax

15 15 Microorganisms Disease Infection Food deterioration

16 16 Experiment and assignment !!!

17 17 Sampling of microorganisms Materials: Different kinds of Bread Conditions: How to “culture” the samples?

18 18 Strategy Different types of bread / Why? Living conditions or how to culture / How? What do you want to sample / What?

19 Bread Mold http://encarta.msn.com/media_461516551/Black_Bread_Mold.html http://www.garden.com.hk/web/en_product.php?id=13&language=en http://www.glad.com.au/gladProducts/foodDetails.asp?pId=12

20 20 How to make use your bread? Cut it into equal size? Use as original size? Record the nature of the bread used? Sampling area – should we sample dirty area or clean area? Or both? Any control experiment required? What kind of “Control”? Method of sampling: basically by contact or swabbing (How hard should I swab?) What kind of microorganisms are expected to be collected?

21 21 http://www.biofilmsonline.com/cgi-bin/biofilmsonline/ed_drop_plate_methodA.html http://www.ars.usda.gov/is/AR/archive/oct05/air1005.htm Diagram showing cultivated microbes

22 Zip bag Bread Condition 1 Nature of the bread: (Brand name, characteristics, or you can do a summary table as a key underneath) Sampling area: Method of sampling: Any moisture added? How long did it take to have the first lawn of microorganism appears? Any moisture added into the bag before culturing? Observation: Type(s) of microorganism appear(s ) onto the day: Zip bag Bread Condition 2 Nature of the bread: (Brand name, characteristics, or you can do a summary table as a key underneath) Sampling area: Method of sampling: Any moisture added? How long did it take to have the first lawn of microorganism appears? Any moisture added into the bag before culturing? Observation: Type(s) of microorganism appear(s ) onto the day:

23 Zip bag Bread Zip bag Bread Consider different sample treatment being collected in the same way? (e.g. under sunlight, in refrigerator, in a moist / damp area, etc.) Zip bag Bread Zip bag Bread Both treated in the same way but sampled from different areas? A from area 1 and B from area 2 AB

24 24 Assignment – Submit a proposal A comprehensive record of your experiment (method / strategy) A complete record of your result e.g. What kind of microorganism you have collected? Matching it with reference book / internet source? Comparisons of your result with different sampling and treatment method? Take photos if necessary Organize your method and result in a report format Each group submit one report and a short PowerPoint Presentation (5 minutes, 10-15 slides)

25 25 How mold looks like? Start up of mold development on culturing medium Well-developed mold in the same medium

26 Where does mold grow? http://www.moldinspector.com/mold_photo.htm

27 27 Bread mold http://encarta.msn.com/media_461516551/Bla ck_Bread_Mold.html http://www.nimr.mrc.ac.uk/news/2006/wellcome_img/mould/ Credit: Liz Smith / Wellcome Images

28 28 Other microorganisms…… Candida albicans (yeast) Listeria monocytogenes (bacteria)MRSA (Methicillin-resistant Staphylococcus aureus) 抗藥性金黃色葡萄球菌 http://www.bd.com E.coli O157 Salmonella 沙門氏菌 http://www.oxoid.com


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