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10 Cards in this Set
- Front
- Back
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Oxygen Requirements
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Fluid Thioglycollate Medium
Media contains: glucose, cystine, and sodium thioglycollate resazurin turns media pink in presence of oxygen Aerobe- top of media Facultative- throughout Anaerobe- bottom of media |
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Gelatin Liquefaction Test
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Nutrient Gelatin
used to determine organisms ability to produce gelatinase, which liquifies gelatin Positive- gelatin is liquefied Negative- gelatin is solid |
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Carbohydrate Fermentation
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Glucose, Lactose, Mannitol, Maltose and Sucrose Broths
Used to determine the organisms ability to ferment a specific carbohydrate with or without the production of gas Phenol red is used as an indicator in the media Fermentation causes acid Positive- Media turns yellow (acidic) Negative- Media stays red (stays neutral) |
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Methyl Red Test
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Used to determine the organisms ability to produce mixed acid and products from glucose fermentation
formic acid--formic hydrogen lyase--> CO2+ H2 Positive- red color develops Negative- yellow color develops |
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Voges-Proskauer Test
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Used to determine the organisms ability to produce acetoin, 2,3 butanediol, and ethanol which cause less lowering of the pH than methyl red postive organisms
add 18 drops of Barritt's Solution A and 18 drops of Barritt's Solution B agitate for 1-2 min, sit 30 min positive- wine red negative- brown color |
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Catalase Test
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Tryptic Soy Agar slant
Used to test for the presence of enzyme catalase. It decomposes peroxide. Obligate anaerobes and aerotolerant bacteria lack this enzyme. add 3 drops of H202 (peroxide) Positive- bubbling (02 gas is liberated from h202) negative- no bubbling |
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Oxidase Test
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Tryptic Soy Agar Slant
Used to determine the presence of oxidase enzyme. Obligate aerobes have this enzyme to oxidize various substrates through the cytochrome oxidase system. Touch with sterile swab, add oxidase test reagent to swab 10-30 sec. postive- change from yellow to purple Negative- no color change |
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Nitrate Reductase Test
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Nitrate Broth
Used to determine the organisms ability to reduce nitrate (NO3) to nitrite(NO2) or nitrogen gas (n2) by nitrase boil and cool media, add 5 drops nitrate reagent A (Sulfanilic acid) and 5 drops of nitrate reagent B (Dimethyl alpha naphthalamine) Postive- red color, nitrate reduced to nitrite Negative- no color change- do confirmation test by adding small pinch of zinc powder: postive: no color change, organism reduced nitrate to nitrogen gas negative: red color, nitrate reuced zinc, not the organism |
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Starch Hydrolysis
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Starch Agar Plate
Used to determine the ability of an organism to break down starch by amylase drop small amount of IKI onto plate Positive- zone of clearing around streak line Negative- no clearing |
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Casein Hydrolysis
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Skim Milk Agar
Used to determine organisms ability to produce the enzyme caseinase which breaks down casein (white powder in milk) to more soluble products positive- zone of clearing around streak line negative- no clearing |
