MBIO 3812 Ex 5-14 Casein Test

MBIO 3812 Ex 5-14 Casein Test - plate • bacteria grows on...

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MBIO 3812 Ex 5-14 Casease Test Casein: phosphoproteins 4 different types which accounts for ~80% of the proteins found in cow's milk gives milk its white color contains between 200-220 amino acids 11
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casein can provide a source of amino acids for certain bacteria Problem: casein is too large to pass through the bacterial cell membrane to overcome this problem certain bacteria possess CASEASE an enzyme that can break down casein MBIO 3812 Ex 5-14 Casease Test 22
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SECRETED enzyme that can break the peptide bonds between adjacent amino acids breakage of peptide bonds produces smaller peptides and eventually individual amino acids that can be taken up by the bacterium MBIO 3812 Ex 5-14 Casease Test 33 Casease:
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Media used in the casease test: Milk agar the most important component is powdered nonfat milk (the source of CASEIN ) casein in the milk provides the substrate that can be used by casease MBIO 3812 Ex 5-14 Casease Test 44
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Possible results of the Casease Test: casein = white color of the milk
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Unformatted text preview: plate • bacteria grows on the milk agar plate • NO change in the color in the color of the agar plate where the bacteria have grown • since media remains white no break down of casein • NO casease produced MBIO 3812 Ex 5-14 Casease Test 55 CASEASE NEGATIVE Possible results of the Casease Test: MBIO 3812 Ex 5-14 Casease Test 66 CASEASE POSITIVE • casein = white color of the milk plate • if a bacterium has casease it will be secreted • once secreted casease will diffuse out through the agar • casease breaks down the casein in the agar • when casein broken down the white color of the agar is lost • a zone of clearing is observed around the bacteria MBIO 3812 Ex 5-14 Casease Test 77 Possible results of the Casease Test: Zone of clearing around the bacteria indicates secretion of casease Casease has broken down the casein in the media leaving the agar clear...
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This note was uploaded on 09/26/2011 for the course MBIO 3812 taught by Professor Staff during the Fall '11 term at The University of Oklahoma.

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MBIO 3812 Ex 5-14 Casein Test - plate • bacteria grows on...

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