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20 Cards in this Set
- Front
- Back
Streak Plate Technique
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Spreads a bacterial culture over the surface of a plate
Label Divide into 4 quadrants Spread innoculum throughout first quadrant Flame loop, start in old quadrant, pass from old to new 3 times Spread culture only in new quadrant Repeat for Q3 & 4 Incubate |
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Streak Plate Purpose
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Purify mixed culture
Check culture to determine if it is contaminated |
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Viable count
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Only considers number of LIVE, colony-forming cells
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Viable count procedure
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Perform a serial dilution
Add 0.1 - 1 ml to media plate by pour or spread plating Incubate plates Count number of colonies/plate Calculate |
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Serial dilution--why?
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To make the necessary calculations, you need isolated colonies. The number of cells in the original sample is often very large, so need to dilute in order to get a smaller amount
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Colony
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Pile of (ideally) genetically identical cells (=clones) that (ideally) originated from one cell. Cells are microscopic, colonies are macroscopic.
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Bioluminescent bacteria
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Vibrio and photobacterium
Photobacterium species live in Flashlight Fish; receive nutrients from fish and in return provide a unique device for frightening would-be predators |
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Enzyme the produces visible light
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Lucierase
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Bioluminescent organism used in lab; grows within what organism?
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Vibrio Fisheri
Colonizes and grows in light organ (head region) of Hawaiian bobtail squid |
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Thioglycollate Media
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Ingredients:
Yeast extract, dextrose (provide nutrients) Low amount agar Thioglycollate (reduces O2 to H2O) Resazurin (O2 indicator + O2 -> pink; -O2 colorless) Purpose: Determine O2 requirement of bacterium, grow anaerobic organisms Differential Media Results Bacteria on top: obligate aerobe All over: Facultative aerobe Midway: microaerophile On bottom: strict aerobe |
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Blood agar plate
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Ingredients:
TSA + 5% sheep's blood Differential Media Purpose: ID bacteria that produce hemolysin (toxin that lyses many cell types including RBC) Help ID streptococcus pyrogenes (strep throat) BAP is a rich media that facilitates growth of fastidious (hard to grow) bacteria Results: Alpha hemolysins - green halo around growth (enterobacter aerogenes) Beta hemolysins - lyse RBC's which CLEARS RBCs on plate (streptococcus aureus) No hemolysis - No change |
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Snyder Media
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Ingredients: Low pH
Glucose pH indicator (bromcresol green) Agar Purpose: Determine if person has bacteria in mouth that can cause tooth decay (dental carries) and if so, to what degree. Differential (glucose fermentation, low pH) and Selective (media has ingredients that inhibit growth of some organisms and enhances growth of others) Results: + = yellow - = green |
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Anaerobic jar
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Purpose: growth of obligate anaerobes in petri
How? Chamber with sealed lid Gas generator pack releases H2 and CO2, H2 reacts with O2 --> H2O Pallidium catalyst O2 indicator strip, Methylene blue Results: +O2 --> blue -O2 --> colorless |
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Beta hemolysis
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staphylococcus aureus
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Majority of flora in throat is which type?
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Alpha
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hemolysin
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toxin secreted from cell, destroys RBC
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Hemolysis
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destruction of RBCs
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Differential media
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distinguishes one microorganism type from another growing on the same media
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Selective media
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Used for growth of only select organisms
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Bacteria responsible for dental carries
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lactobacilli, oral streptococci
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