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36 Cards in this Set
- Front
- Back
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Resolution |
separation of fine details such as two closely situatedpoints such that the two points appear distinct and separate |
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Numerical Aperature |
number that indicates the ability of a lens to gather lightfrom the specimen |
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Formula for Resolving Power |
R.P. = wavelength of light being used/(N.A. condenser + N. A. objective) |
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What does a resolving power of 0.30um mean? |
we can distinguish two points from each other ifthey are at least 0.30 um away from each other |
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Immersion Oil |
light moves continuously from sample to objective without refraction |
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Subculturing |
transferring from one inoculated medium to another uninoculated medium |
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Components of Colony Morphology |
- Size - Elevation - Margin - Surface - Pigmentation |
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Simple Staining |
- single dye or reagent which will allow us to see acontrast between the microbe and its background - Basic Dye--> Methylene Blue |
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Gram-positive bacteria |
Hold stain |
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Gram-negative bacteria |
Lost stain |
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Colony Morphology: Size |
- Pinpoint - Small - Moderate - Large |
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Colony Morphology: Elevation |
- Flat - Raised - Convex - Crateriform - Umbonate |
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Colony Morphology: Margin |
- Entire - Lobate - Undulate - Serrate - Filamentous |
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Colony Morphology: Surface |
- Smooth - Rough - Concentric - Wrinkled |
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PEA Medium |
- Selective - Selects FOR growth of G+, inhibiting G- - Presence of 0.025% phenylethyl alcohol |
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MacConkey Agar |
- Selective & Differential - Selects FOR G- - Selects AGAINST G+ - Bile salts and crystal violet stain (Selective) - Carbohydrate lactose, pH indicator (neutral red) Differential |
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Psychrophiles |
temperature range of –5 to 20 |
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Mesophiles |
temperature range of 20 and 45 |
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Thermophiles |
temperature range 35+ and above |
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Facultative thermophiles |
37 with an optimum growth temperature of 45-60 |
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Obligate Thermophiles |
temperatures above 50 with optimum growth at temperatures above 60 |
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Petroff-Hausser cell counter |
- Cell counter has a grid, and each square on the grid has afixed volume of sample that lies above it - count the numbers of bacteria on the grid, work backwards, figure out how many bacterial cells were in our original sample |
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Plate Count Method |
- serial dilutions of a sample, platingthem, incubating the plates, and waiting for individual colonies to form - usable data from a plate that has 30-300 colonies |
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Formula for colony forming units |
CFU/mL= # colonies on plate/((dilution)(volume of diluted sample plated) |
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Pour Plate Method |
- pour molten agar (kept at 50) into petri dishes that contain dilutedbacteria. Once these plates solidify (when temperature drops to 40 and below), we incubate the platesand wait for growth |
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Optical Density |
- indirect count of bacteria - amount of light scattered by the bacteria is related to the number ofbacteria in the sample |
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Biofilm |
- bacteria plus various extracellular carbohydrate polymers that help the bacteria attach to the teeth and toeach other - Dental plaque |
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Bacteria known to contribute to cavities |
- Lactobacillus acidophilus - Streptococcus mutans - Actinomyces odontolyticus |
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Synder Test |
- determine's a person’s susceptibility to dental caries - differential test - agar that containslactobacilli growth requirements plus glucose and the pH indicator bromcresol green - green between about pH 4.6-5.4 - yellow below |
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Indole Test (General) |
- assess ability of a bacterium to degrade the tryptophan ~ carry a gene for tryptophanase ~ hydrolyzes tryptophan to indole, pyruvic acid, and ammonia |
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Kovac's Reagent |
- Used in Indole test - p-dimethylaminobenzaldehyde, butanol, and hydrochloric acid - + rxn--> red indole ring--> tryptophanase |
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Methyl-Red Test Analysis |
- associated with MR-VP - pH indicator - < 4.4 --> red (mixed acid ferm!) - 4.4-6.0 --> orange (not + or -) - >6.0 --> yellow (no mixed acid ferm!) |
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Voges- Proskauer |
- identify organisms that can produce acetoin fromglucose fermentation - Produce acetoin--> red - No acetoin--> no color change - Orange isn't a result |
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Barritt's Reagents |
- Used for VP test - A--> a-naphthol - B--> KOH |
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Citrate Utilization Test (General) |
- Simmons citrate agar - CO2 from citrate metabolism combines with sodium and water in the Simmons citrate agar, formingsodium bicarbonate - bromothymol blue pH indicator |
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Citrate Test Analysis |
- green below 7.6, but turn blue above pH 7.6 - positive reaction as bothgrowth and blue medium |
