LECTSTEPHEN
Lab 6 Notebook
BS06 Introduction to Enzymatic Assays
Objective: To profile bacterial populations based on key enzymatic reactions and determine
growth/metabolic characteristics.
Notes:
Oxidase test: Qualitative (yes or no) test to determine the presence or absence of
cytochrome c oxidase activity in bacteria.
o Cytochrome c: component of the electron transport chain in aerobic bacteria
such as pseudomonas.
If positive test=an aerobic bacterium.
Commonly used to identify Neisseria, which is a causative agent of
gonorrhea.
Used in hospital settings
o Procedure:
1. Using a sterile loop pick an isolated colony from BAP
(blood agar plate)
2. Smear directly onto the reaction area of the slide.
3. Examine test area for color change within 20 seconds.
Oxidase negative = no color change
Oxidase positive = purple color
Catalase test: Qualitative (yes or no) test to determine the presence or
absence of catalase, an enzyme used to break down hydrogen peroxide.
o Catalase: vital to have in an oxygen rich environment. This is because hydrogen
peroxide can easily be formed. If left unattended, hydrogen peroxide forms
oxygen radicals.
Detrimental to a bacteria cell, will lead to cell killing rather quickly.
o Test used to differentiate staph from strep.
Both are gram-positive bacteria, both have a round or spherical shape
Staph is catalase positive.
Differential test
o Procedure:
1. Using a sterile loop carefully pick colony from
plate.
2. Smear colony directly onto glass slide.
3. Add 2 drops of hydrogen peroxide to each
smear.
Catalase negative = no bubbles
Catalase positive =bubbles
This study source was downloaded by 100000829684747 from CourseHero.com on 03-18-2022 21:53:41 GMT -05:00
https://www.coursehero.com/file/102330779/Lab-6-Notebookdocx/
Lab 6 Notebook
BS06 Introduction to Enzymatic Assays
Objective: To profile bacterial populations based on key enzymatic reactions and determine
growth/metabolic characteristics.
Notes:
Oxidase test: Qualitative (yes or no) test to determine the presence or absence of
cytochrome c oxidase activity in bacteria.
o Cytochrome c: component of the electron transport chain in aerobic bacteria
such as pseudomonas.
If positive test=an aerobic bacterium.
Commonly used to identify Neisseria, which is a causative agent of
gonorrhea.
Used in hospital settings
o Procedure:
1. Using a sterile loop pick an isolated colony from BAP
(blood agar plate)
2. Smear directly onto the reaction area of the slide.
3. Examine test area for color change within 20 seconds.
Oxidase negative = no color change
Oxidase positive = purple color
Catalase test: Qualitative (yes or no) test to determine the presence or
absence of catalase, an enzyme used to break down hydrogen peroxide.
o Catalase: vital to have in an oxygen rich environment. This is because hydrogen
peroxide can easily be formed. If left unattended, hydrogen peroxide forms
oxygen radicals.
Detrimental to a bacteria cell, will lead to cell killing rather quickly.
o Test used to differentiate staph from strep.
Both are gram-positive bacteria, both have a round or spherical shape
Staph is catalase positive.
Differential test
o Procedure:
1. Using a sterile loop carefully pick colony from
plate.
2. Smear colony directly onto glass slide.
3. Add 2 drops of hydrogen peroxide to each
smear.
Catalase negative = no bubbles
Catalase positive =bubbles
This study source was downloaded by 100000829684747 from CourseHero.com on 03-18-2022 21:53:41 GMT -05:00
https://www.coursehero.com/file/102330779/Lab-6-Notebookdocx/
