Tracking Ph Level’s of Food Preferred by Physarum Polycephalum Deborah Belew, Lisa Green, Allison Janecko, Bethany Mackan, Jessica Schleifer and Chris Wilkin Kent State University Stark Campus, Department of Biological Sciences, North Canton ,Ohio USA
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
Tracking Ph Level’s of Food Preferred by
Physarum Polycephalum
Deborah Belew, Lisa Green, Allison Janecko, Bethany Mackan,
Jessica Schleifer and Chris Wilkin
Kent State University Stark Campus, Department of Biological Sciences, North Canton ,Ohio USA
INTRODUCTION
What is Physarum Polycephalum?True slime moldLife process
How does it obtain food?Surrounds foodSecretes enzymes
Does Physarum polycephalum typically prefer food that is acidic or basic?
Our question:Given a choice in a controlled environment, would it prefer acidic, basic, or neutral foods?
We believe that Physarum polycephalum will seek out the oat mixtures that are most neutral in Ph level.
HYPOTHESIS
METHODS Tested several items for Ph level utilizing Ph testing strips
provided by the lab
Selected 5 items with varying Ph levels (Table 1)
Obtained a culture sample of Physarum polycephalum from culture dish provided by the lab
Removed a 1 square cm section from culture. Used test tube caps initially to cut out sections then utilized scalpel for transfer to new dish.
Discussed contamination with Dr. Bernstein. Decided transferring the slime mold with the sterilized scalpel provided less contamination. Kept dishes exposure to air to a minimum by uncovering dishes only during transfer.
PH LEVELS
Table 1: Examples displaying range of Ph levels
Used a set ratio (Table 2) of oats and variable ingredient in each mixture
METHODS CONTINUED
1/8 tsp water 1/8 tsp of item A ½ tsp oats
1/8 tsp water 1/8 tsp of item B ½ tsp oats
¼ tsp water ½ tsp oats
Table 2: Ratio of ingredients
Set up Petrie dishes
3 different samples in each dish each time Carved 3 pathways in agar from center to each sample Maintained a “control” sample within each of water/oats Dish stored in drawer for 2 – 4 days
• Does not have an apparent preference for either acids or bases thus far.
• Decide to start 2 new experiments. – One with “likes” from test 1 & 2
• (Egg/oats, hot sauce/oats) & water/oats neutral control
– One with “dislikes” from test 1 & 2 • (water/oats, scope/oats) & water/oats neutral control
In the dish containing the “dislikes” it appears to travel along the side of the agar path and settle on the neutral water/oat sample. This data suggests that it does not like the base or the acid.
• In the dish containing the “likes” our slime mold appears to have moved directly to the egg/oats sample.
RESULTS
Appears to prefer the egg/oats sample thus farWhy? What does each part of the egg contain?
Decide to separate the yolk from the albumen & test the slime mold’s preference for either.
Figure 1: Diagram of egg structure (wicker.myweb.uga.edu/eggs)
Also run another test:Soy milk vs. egg Reassure the preference for the egg as opposed to the preference for oats mixed with any base, as milk & egg both test as bases.
TABLE 2: Data showing Ph levels & whether the slime mold preferred or disapproved of that item.
Variable Ph level Slime Mold Preferred?
Soy milk 8 no
Milk of magnesia 10 no
Scope 5 no
Hot Sauce 3 yes
Egg (scrambled) 8 yes
Egg yolk 6 yes
Albumen (Egg white)
7.6 no
Figure 2: Hot sauce vs. Scope
Figure 3: Contamination
What do eggs contain that the other bases tested did not?
Eggs become more alkaline in pH level as they age according to Oregon State University. How would the slime mold react to freshly laid eggs opposed to store bought eggs?
Would Physarum polycephalum react differently to egg
substitutes?
Did bacteria on the egg have a role in the outcome of the experiment?
Would maintaining a cooler temperature thwart bacterial growth & harbor a different result?
NEW QUESTIONS
•Choose several different types, grades, ages of eggs and egg substitutes.
•Select cleaner agar Petrie dishes
•Study samples under several different temperatures
•Increase our quantity of sample dishes
•Decrease the time exposed to air
•Take samples from the same initial culture
NEXT STEPS
http://food.oregonstate.edu/learn/egg.html , Date accessed 12/2/08
REFERENCES
http://www.baking911.com, Date accessed 2008
http://www.dailyplate.com, The Daily Plate website for nutritional and dieting information “ Nutritional Information on the Egg, Date accessed 11/20/2008
Vadehra, D.V. and K.R. Nath. 1973. Eggs as a source of protein. CRC Critical Reviews in Food Technology 4: 193-309
http://lwicker.myweb.uga.edu/eggs_files/image004.jpg, Date accessed 11/30/08
The United States Department of Agriculture, “The United States Standard, Grades, and Weight Classes for Shell Eggs.” July 20, 2000. Date accessed 11/20/ 2008