Micro Lab Test 3

1. Oblugate aerobe
2. facultative anaerobe
3. aerotolerant
4. obligate anaerobe

1. by inoculating broth via loop
2. tests for bacteria's ability to ferment sucrose/lactose/mannitol and produce gas and/or an acid end-product
3. broth contains beef extract, the specific sugar, and a phenol red indicator to indicate acid end product, a durham tube is added to indicate gas production.
4. + for acid is yellow (indicating fermentation)
+ for gas is gas bubble in durham tube
- gas is no bubble
- for acid is no color change or reddish orange color

1 - negative acid / negative gas

2A - must incubate longer

2B - positive acid / neg. gas

3A - positive acid / positive gas

1. Inoculate broth with loop
2. tests for bacteria's ability to use the mixed acid pathway, which produces acidic end products such as lactic, acetic, and formic acid when glucose is fermented
3. broth contains peptone, glucose and phosphate buffer. A methyl red indicator is added to indicate acid end products
4. Red - positive
orange - yellow - negative

1st is control
2nd neg.
3rd is positive

1. Inoculate slant with needle and stab
2. bacteria that has the ability to consume citrate as the sole source of carbon, and ammonia salt as the sole source of nitrogen
3. + is blue (meaning bacteria metabolized citrate and pH increased.
- remains green

Blue is +
Green is -

1. inoculate urea broth with loop
2. determine bacteria's ability to hydrolyze urea to make ammonia using the enzyme urease
3. Urea broth and phenol red indicator
4. urea broth is naturally yellow gold color, if the enzyme urease hydrolyzes urea to make ammonia it will turn a bright pink color
- if no change in color or color is orange(ish)

1st is positive
2nd is negative

1. Inoculate tryptone broth with loop
2. tests for bacteria's ability to produce indole, the enzyme tryptophanase breaks down tryptophan, indole is of the byproducts
3. tryptone broth contains tryptophan, a kovac reagent is used
4. after kovac's reagent is used, it + kovacs will react with indole and make a red colored line on top, negative there is no red line

See question

1. streak plate. after incubation add H2O2 to the colonies, observe for bubbling
2. testing for the bacteria's ability to produce catalase that breaks down H2O2 onto water and CO2
3. Bubbles formed = +
no bubbles = -

1. divide starch plate in 2 with marker on bottom of plate, streak control on one side, bacteria specimen on other
2. Testing for exoenzymes, inculding a-amylase and oligo -1, and 6 - glucosidase that hydrolyze starch. Starch is too large to enter bacter cell, so the bacteria may sevret exoenzymes to degrade the starch into subunits that can be used by the organism
3. starch agar is a simple nutritive agar with starch added. Iodine is added, since no color change occrurs in medium when organisms hydrolyze the starch.
4. A clearing around the bacterial growth indicates the organism, has hydrolyzed the starch.

Left is -

Right side is +

A - Polar
B - lophotrichous
C - peritrichous
D - amphitrichous