Susan Hollingsworth
Aaron Kaiser
Biology 110
Lab # smh092404
Purpose:
 To observe multiple environments that harbor
bacterial growth and determine which
environment under investigation is most
conducive to bacterial growth
 Environments under investigation:
air
soil
washed/unwashed hands
door handle of men’s bathroom
raw chicken
pond water
Hypothesis:
 Pond Water
 largest and most diverse population of
bacteria due to a vast array of living and
decomposing organisms that are
vulnerable to bacterial colonization
 aquatic medium that receives sunlight
(some bacteria are photosynthetic)
 exposed to air which transports bacterial
spores.
Materials:
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7 sterile Petri dishes with nutrient agar
Wax pencil
9 bacterial inoculating loops
Sterile cotton swab
Piece of raw chicken
Soil sample
Pond water sample
Hand soap
Sterile water
Parafilm strips
Light microscope
Dissecting microscope
incubator
Method:
1. Label each Petri dish
2. “Air” sample
3. Use Streak Plate method to apply sample
(a)
(b)
(c)
Figure 1. Isolating bacterial colonies using the “Streak Plate”
method.
4. Unwashed/Washed hand sample
5. Recover dish labeled “air.”
6. Wrap cultures with Parafilm and incubate upside
down for 1 week.
Data Interpretations:
The Petri dishes will be analyzed by using colony
morphology characteristics to see which one has
the most species of bacteria. This will be
accomplished by identifying and tabulating the
number of different colonies present in each
sample.
Table 1. Bacteria colony morphology: Air
Colony
Size
Shape
Margin
Surface
Color
a.
6mm
Irregular
Lobate
Wrinkled
Milky white
b.
4mm
Round
Wavy
Smooth
White center,
clear
surrounding
c.
13mm
Irregular
Lobate
Smooth
White center,
milky white
surrounding
d.
5mm
Irregular
Wavy
Smooth
Yellow, gold,
clear
surrounding
e.
9.5mm
Irregular
Wavy
Smooth,
contoured
edges
Tan center,
white ring,
clear ring
Fig. 2 Bacteria
present in Air
environemnt
Table 2. Bacteria colony morphology:
Chicken
Colony
Fig 3. Bacteria found on
Chicken environment
Shape
Margin
Surface
Color
a.
1mm
Round
Lobate
Wrinkled
Creamy
white to
slightly
yellow
b.
5mm
Round
Smooth
Smooth
white
Table 3. Bacteria colony morphology: Soil
Colony
Fig 4. Bacteria found on
soil environment
Size
Size
Shape
Margin
Surfac
e
Color
a.
10mm
No
defined
shape
No
defined
margin
Wrinkled
Clear
b.
Less than
1mm
Irregular
Lobate
Wrinkled
Cream
white
Table 5. Bacteria colony morphology: washed hand
Colony
Shape
Size
Margin
Surface
Color
a.
3mm
Round
Lobate
Smooth
Creamy
white
b.
4mm
Round
Lobate
Smooth
Clear
c.
Punctiform
Round
Smooth
Smooth
white
Fig 5. Bacteria found on washed and
unwashed hand environments
Table 4. Bacteria colony morphology: unwashed hand
Colony
Size
Shape
Margin
Surface
Color
a.
8mm
Irregular
Smooth
Smooth
Yellow
b.
8mm
Round
Lobate
Smooth
Clear to creamy
white
c.
3mm
Round
Smooth
Concentric
White
d.
2mm
Round
Lobate
Smooth
Clear to off white
e.
3mm
Round
Lobate
Wrinkled and
smooth
Clear
f.
Punctiform on e.
Round
Smooth
Smooth
Slightly white to
clear
g.
7mm
Irregular
Wavy
Smooth
Creamy white
Table 6. Bacteria colony morphology: pond water
Colony
Size
Shape
Margin
Surface
Color
a.
4mm
Round
Lobate
Smooth
Tan to white
b.
1mm
Round
Smooth
Smooth
Orange
c.
5mm
Round
Smooth
Smooth
Clear to off
white
d.
30mm
Irregular
Lobate
Smooth
trasparent
Fig 7. Bacteria found on pond water
environment
Table 7. Bacteria colony morphology: Men’s
bathroom door
Colony
Size
Shape
Margin
Surface
Color
a.
3mm
Round
Lobate
Smooth
Clear
b.
3mm
Round
Lobate
Smooth
Orange
c.
10mm
Round
Smooth
Smooth
yellow
d.
10mm
Round
Smooth
Smooth
white
e.
6mm
Round
Wavy
Mucoidal
white
Fig 8. Bacteria found on bathroom door environment
Side Study: Effect of Antibiotics on
E. coli growth
Antibiotic
Sensitivity
Chloramphenicol30mg
NS
Penicillin-10mg
NS
Nalidixic Acid-30mg
VS*
Norobiocin-30mg
NS
Streptomycin-10mg
VS
Erythromycin-15mg
S
Tetracycline-30mg
VS
Kanamycin-30mg
VS
Fig 9. E coli growth among
antibiotics