Transcript Experiment Using Colony Morphology Characteristics to

EXPERIMENT TO
DETERMINE IF CHILI
POWDER AND CLOVES
AFFECTS THE GROWTH
OF Saccharomyces cerevisiae.
Mike Bohner
Pandelee Mikroudis
Jason Hinkle
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Team of
Investigators
Jason Hinkle
Mike Bohner
Pandelee Mikroudis
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Basic Information


Saccharomyces cerevisiae is
commonly known as the
baking/brewing yeast.
S. cerevisiae ferments the
sugars found in flour. This
gives off carbon dioxide and
alcohol. As the carbon
dioxide gets trapped inside
the dough, it forces the
dough to rise.
Figure 1: Fermentation of S. cerevisiae
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Purpose:
The purpose of this experiment
was to determine if cloves and
chili powder inhibit the growth of
Saccharomyces cerevisiae.
Through background research, we
have learned that evidence directly
supports that the yeast, S. cerevisiae,
grown in culture is inhibited by cloves
(25mg/mL and 100mg/mL) and chili
(25mg/mL and 100mg/mL) when
incorporated into nutrient agar
(De et al., 1999).
Figure 2: Scanning electron
micrograph of S. cerevisiae.
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We hypothesize that the growth of S. cerevisiae will be
inhibited by the spices chili powder and clove. Herein,
we replicated the work of De et al., (1999) in order to
partially repeat their experiment and to analyze the
antifungal affects of the spices chili powder and cloves
specifically.
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Methods
There were five Petri dishes used:

Two possessing only nutrient agar for control
purposes

One possessing nutrient agar inoculated with
S. cerevisiae
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One possessing nutrient agar heavily concentrated
with cloves and inoculated with S. cerevisiae

One possessing nutrient agar heavily concentrated
with chili powder and inoculated with S. cerevisiae
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Methods
The “Streak Plate Method”
Figure 3: The Streak Plate Method
1. The “Streak Plate Method” was used
for inoculation of appropriate
experimental plates.
2. All plates, experimental and controls,
were incubated for 5 days at 37O C.
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Controls

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Two Petri dishes possessing only nutrient agar were designated
as controls.
The agar control remained unopened throughout the
experiment to rule out contaminated nutrient agar.
The air control was exposed to the air in order to disregard
bacterial and fungal species that may have traveled as spores
and contaminated the experimental plates.
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Methods
Following the incubation period, a piece
of transparent graph paper was placed
over the appropriate Petri dishes in order
to analyze and quantitate yeast growth.
Observations were made using a
stereoscopic microscope.
The number of fungal colonies were
counted in a one square cm. area of the
appropriate Petri dishes. Then the average
number of colonies in one square cm.
area was multiplied by the total area of
the Petri dish to get the average number
of colonies found in the entire Petri dish. Figure 4: Photograph showing the use of
transparent graph paper to quantitate
(A= π x r2)
yeast growth.
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Results:
Nutrient Agar
Control
Figure 5: Nutrient agar control showing no
microbial growth.
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Results:
Species 2
Open Air Control
Species 1
Figure 6: Open air control showing microbial growth
Species Number
Shape
Margin
Surface
Color
Size
Species One
Round
Smooth
Smooth
Light blue
1/2cm
Species Two
Irregular
Lobate
Smooth
Orange
1cm
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Results:
S. Cerevisiae grown on
Nutrient Agar
Figure 7: S. cerevisiae grown on nutrient agar
Total area of
Petri dish
 x r2
 x 3.8cm2
45cm2
Total area
covered by S.
cerevisiae
10%
Average number of colonies
found in one cm2
Estimated number of colonies
found in Petri dish
55 colonies/cm2
55 colonies x 45cm2 = 2,475 colonies
2,475 colonies x .10 = 248 colonies
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Results:
Bacteria colony
S. Cerevisiae grown on
Chili Powder
Total area of Petri
dish
 x r2
 x 3.8cm2
45cm2
Total area covered by
S. cerevisiae
25%
Figure 8: S. cerevisiae grown on nutrient agar
embedded with chili powder
Average number of
colonies found in one
cm2
Estimated number of colonies found
in Petri dish
87 colonies/cm2
87 colonies x 45cm2 = 3,915 colonies
3,951 colonies x .25 = 978 colonies
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Note: The bacteria found growing in the chili powder was negated by the open air control
Results:
S. Cerevisiae grown on
Cloves
Figure 9: S. cerevisiae grown on butrient agar
embedded with cloves
Note: No S. cerevisiae was found growing on cloves
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Results:
Number of colonies
histogram plotting the number of S. cerevisiae colonies
1200
1000
800
600
400
200
0
cerevisiae S.
S. cerevisiae
cerevisiae nutrient
agar
S. S.
cerevisiae
S. cerevisiae
cerevisiae S.
Nutrient
on nutrient
On nutirent
agar
on chili
on chili
powder
on cloves
Agar
powder
Environment
on cloves
control
open air
air
Open
control
agar
control
control
histogram plotting the number of S. cerevisiae colonies
Figure 10: Histogram plotting the numbers of S. cerevisiae colonies
verses designated Petri dish environment.
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Conclusion
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
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Our hypothesis was not fully supported by
the data.
While cloves was a potent inhibitor of
S. cerevisiae, chili powder was not.
Our data suggests that chili powder actually
enhanced the growth of S. cerevisiae.
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Further Analysis

According to previous research by De et al., 1999 ,
chili powder should have inhibited the growth of
S. cerevisiae at 25mg/mL and 100mg/mL. We believe
that when the Petri dish of chili powder was created,
most of the powder settled at the bottom of the Petri
dish leaving the top with a small concentration of
chili powder (<25mg/mL). If we were to repeat this
experiment, we would prepare our own Petri dishes to
ensure an accurate concentration of chili powder.
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Further Analysis
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The transparent graph paper method was
not entirely accurate. In order to accurately
calculate the number of colonies, a more
precise method would is needed to count
the number of colonies inside an area of a
cm2.
A more precise method needs to be used to
count the total area that the fungus covered,
which could significantly affect our results.
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Further Analysis

In future experimentation we will more closely
examine the chemical constituents in cloves in
order to understand the cellular mechanisms
behind its inhibition of S. cerevisiae growth.
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To do this we will employ electron microscopy
and florescence microscopy techniques.
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References
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Morgan, I. G, and Brown Carter, M.E.,
Investigating Biology. Benjamin/Cummings
Publishing Co., Inc. 2002.
Minakshi De, Amit Krishna De, and A. B.
Banerjee. (1999). Antimicrobial Screening of
Some Indian Spices. Phytotherapy Research,
13 (7), 616-618.
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Producers:
Jason Hinkle, Pandelee Mikroudis, Mike Bohner
SPECIAL THANKS TO:
Dr. McLaughlin
Mazin Albert
Samer Moussa
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