Lab 7 Goals and Objectives:

Read the results: Gather all plates and tubes so we can discuss results together: ***Do NOT shake the FTM tubes!!!***

Your Unknowns: Exercises 37 and 38Check plates, record appearance, check for contaminationCheck slants for growth and place in my “reserve” rack

Make new inoculations for both unknowns from the plates

Motility Test Media Results

Non-motile Motile

Not Motile

Discriminates motility (presence of flagella), ability to “swim” through media Results: organism growing only in line of inoculation = non-motile organism appears as haze beyond line of inoculation = motile

Oxygen requirements1. Fluid Thioglycolate Medium (FTM)Results:growth only at top = obligate aerobe

growth only at bottom = obligate anaerobeeven growth throughout = aerotolerantheavy growth at top, lighter growth at bottom = facultativegrowth only in middle = microaerophile

2. Brewer’s Anaerobic AgarResults: growth on aerobic agar only = obligate aerobe

growth on anaerobic agar only = obligate anaerobeeven growth on both = aerotolerantheavy growth on aerobic, lighter growth on anaerobic = facultative

Fig 21.4

Fig 27.2

Which Groups Grow on Anaerobic Agar In the Anaerobic Jar?

Which Groups Grow on Brewer’s in 20% Oxygen?

Brewer’s No Oxygen Brewer’s 20% Oxygen

Obligate aerobes: 20% O2

Obligate anaerobes: O2 toxicFacultative: w/ or w/o, better with O2

Microaerophiles: 5-10% O2

Aerotolerant: ignore O2

Obligate aerobes: 20% O2

Obligate anaerobes: O2 toxic

Facultative: w/ or w/o, better with O2

Microaerophiles: 5-10% O2

Aerotolerant: ignore O2

Fig 27.1

Fig 27.5

Your Unknowns: Exercises 37 and 38Check plates, record appearance, check for contaminationCheck slants for growth and place in my “reserve” rack

Make new inoculations for both unknowns from the plates:1. 2 FTM tubes for O2 requirements (Ex. 38 pg. 267)

**leave caps loose to incubate!

2. 2 BHI broth tubes for growth in liquid characteristics (Ex. 38 pg. 266 fig. 38.2) and for Gram stain (Ex. 37 pg. 260)

3.2 Gelatin stab cultures for gelatin hydrolysis ability (Ex. 38 pg. 259)

4. 3 BHI plates each unknown (6 total), streak for isolation, to grow at 25°C, 30°C, 37°C to determine optimal temp. (Ex. 37&38 had you using slants and broths; side by side plates is easier)

5. 2 Motility test media stabs (Ex. 37 pg. 262) No: KOH, endospore, acid fast, other structures (Ex. 37 pg. 261-262)

Nutrient Gelatin StabInoculation method: stab with needleContains: beef extract, peptone, high gelatin concentration to gel (no

agar)Must be set on ice 5-10 min before readingDiscriminates organisms that can produce gelatinases to hydrolyze the

gelatin into amino acidsResults:

liquid = gelatin hydrolysis, positive for gelatinase production solid = negative for gelatinase production

Data to collect for Exercise 37 & 38 For Next Lab

Gram result, size, shape, arrangement

Transfer to Data Chart

Motility Transfer to Data Chart

Amount of growth

Color

Opacity

Form

Surface (broth)

Subsurface (broth)

Sediment (broth)

Growth (broth)

Temperature Transfer to Data Chart

Oxygen requirements (FTM) Transfer to Data Chart

Gelatin Transfer to Data Chart

Colonies

Identification of Unknown Bacterium

For next lab:

Read over formal lab report directions in packet.

State a hypothesis“If the collective results of a profile of key biochemical assays are compared to the known results for limited subset of bacterial species, then a specific unknown culture from that subset of bacterial species can be correctly identified based on the results obtained from the biochemical assays.”

Each pair needs for Lab 7

• 4 motility stabs

• 4 FTM tubes

• 4 gelatin stab

• 4 BHI broths

• 12 BHIA plates