results: organism growing only in line of inoculation ... · exercise 18: motility determination...

Lab 7 Goals and Objectives:

Exercise 18: Motility Determination

Read results

Exercise 27: Effect of Oxygen on Growth

Read results

Understand FTM patterns of growth

Unknown Project

Data collection for profiles

Each pair get one organism to collect data on to share with the

class to develop profiles of all possible organisms. Each person inoculate one BHIA streak for isolation plate and

one BHI broth of assigned organism


Motility Test Medium

Inoculation method: vertical single stab with straight needle Contains: nutrient medium with low (0.5%) agar concentration

(semisolid) and TTC which changes from colorless to dark

pink in the presence of bacterial growth (enhances

visualization)

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

Figure 18.4

Motility Test Media Results

Non-motile Motile Non Motile

Fig 27.1


Obligate aerobes: 20% O2

Obligate anaerobes: O2 toxic

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

Microaerophiles: 5-10% O2

Aerotolerant: ignore O2

Amy Warenda Czura, Ph.D. 1 SCCC BIO244 Lab 7 Notes

Fig 27.1

Fluid Thioglycolate Medium (FTM)

Inoculation method: loop transfer, careful mixing, screw cap must be loose

Contains: rich medium with very low agar content (viscous)

Sodium thioglycolate (removes oxygen)

Resazurin oxygen indicator (pink when oxidized: O2 present)

Discriminates oxygen requirements: obligate aerobes, obligate

anaerobes, facultative anaerobes, microaerophiles, aerotolerant

Results: growth only at top = obligate aerobe

growth only at bottom = obligate anaerobe

even growth throughout = aerotolerant

heavy growth at top, lighter growth at bottom = facultative

growth only in middle = microaerophile

Supplement pg 52

Growth Patterns Observed in FTM Tubes

The gas pack releases H2. This combines with the O2 in the air

creating water. The oxygen is chemically removed from the air

as it gets bound by the hydrogen to form water molecules, resulting in an anaerobic environment in the jar.

Brewer’s Anaerobic Agar

Inoculation method: surface streak with loop, must be incubated in Brewer’s

anaerobic jar (water + gas pack = H2 + CO2, H2 combines with O2 creating

H2O, sealed jar is oxygen free). Inoculate in conjunction with a second

plate in aerobic 20% oxygen atmosphere to determine O2 needs.

Contains: Nutrient agar with sodium thioglycolate and resazurin (see FTM)

Discriminates oxygen requirements if read in conjunction with normal aerobic

incubated plate: obligate aerobes, obligate anaerobes, facultative

anaerobes, aerotolerant

Results: growth on aerobic agar only = obligate aerobe

growth on anaerobic agar only = obligate anaerobe

even growth on both = aerotolerant

heavy growth on aerobic, lighter growth on anaerobic = facultative

Fig 27.2 Fig 27.4


Which Groups Grow on Brewer’s Anaerobic Agar In the Anaerobic Jar?

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

Brewer’s No Oxygen Brewer’s 20% Oxygen

Obligate anaerobes: O2 toxic

Obligate aerobes: 20% O2

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

Microaerophiles: 5-10% O2

Possible Unknowns:

Bacillus subtilis

Enterobacter cloacae

Escherichia coli

Klebsiella pneumoniae

Proteus vulgaris

Pseudomonas aeruginosa

Salmonella typhimurium

Shigella flexneri

Staphylococcus aureus

Staphylococcus epidermidis

Enterococcus (Streptococcus) faecalis

Streptococcus pyogenes

Lab 7 Goals and Objectives:


Read results


Read results

Understand FTM patterns of growth

Unknown Project

Data collection for profiles

Each pair get one organism to collect data on to share with the

class to develop profiles of all possible organisms. Each person inoculate one BHIA streak for isolation plate and

one BHI broth of assigned organism


results: organism growing only in line of inoculation ... · exercise 18: motility determination...

Documents