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

Recorded data in journal & discussed next step

MILK OF MAGNESIA

Ph level 10

Active ingredient: Magnesium hydroxide

Inactive Ingredients: citric acid, D&C red#28, glycerin, sorbitol, sucrose, water, xanthan, gum.

(Medicinenet, 2008)

HOT SAUCE

Ph level 3

Ingredients:Peppers, vinegar, and salt

(Louisiana Pepper, 2008)

SILK SOY MILK Ph level 7.5Ingredients:

filtered water, whole organic soybeans, organic evaporated cane juice, calcium carbonate, natural vanilla flavor, sea salt, carrageen, vitamin A, palmitate, vitamin D2, riboflavin (B2), vitamin B12

(http://www.silksoymilk.com/Products/SilkSoymilkRefrigerated.aspx)

SCOPEPh level 5

Ingredients:15%WT/V Glycerin, Ethanol SD 40Benzoic Acid & Sodium Benzoate (act as buffers)

Cetylpyridinium chloride Sodium Saccharin

Domiphen Bromide FD&C Yellow # 5, FD&C

Blue #1, water

(Household Products, 2008)

SUNNY MEADOW EGGS

Ph level 8

Nutritional facts:calories 90total fat 5gsaturated fat 2gcholesterol 270mgsodium 80mg carbohydrates 1g diet fiber 0gprotein 8g

• ((www.dailyplate.com), Eggs Grade

A)

WATER (control)

Ph level 7 (neutral)

Nutrition Facts :Calories 0Fat 0Carbohydrates 0Protein

(Calorie Count, 2008)

PH LEVELS OF ITEMS

• 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.

New Results

In soy milk vs. egg:Slime mold went directly to the egg

In yolk vs. egg:Slime mold went directly to the yolk as opposed to the water/oats or albumen/oats mixtures.

Why does the slime mold prefer eggyolk over egg white ?

EGG YOLK VS. EGG WHITE

Egg white structure: 7/8 water, 1/8 protein, o fat, niacin, riboflavin, chlorine, magnesium, potassium, sodium and sulfur.

Egg yolk structure: 1/2 water, 1/6 protein, 1/3 fat, emulsifiers (lecithin), vitamins A,D and E

Figure 2: Grades of eggs (The United States Department of Agriculture, 2006)

Data suggests that the

ph level of the “food”

does not entice the

slime mold to select it

as much as the

nutrients available.

END RESULTS

Figure 3: Nutritional Daily Allowance Pyramid(www.ams.usda.gov)

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

http://www.ams.usda.gov/AMSv1.0/gtfile?dDocName=STELDEV3004376

“Louisiana the Perfect Hot Sauce” Nutritional and diatary information. Date accessed

11/22/2008, www.louisianapepper.com

“Milk of Magnesia” Nutritional Drug information. Date accessed 11/26/2008,

www.medicinenet.com/magnesium_hydroxide-oral/article.htm

“Scope: Oral Mouthwash” Nutrition and Ingredients. Date accessed 12/2/2008,

www.householdproducts.nlm.nih.gov

“Silk Soy Milk”, Nutrition and Information page. Date accessed 12/2/2008,.

www.silksoymilk.com/Products/SilkSoymilkRefrigerated.aspx