GMU:Diy biolab drivers license SoSe26/Daria Lukianchuk

Slime Mold and Colored Nutrients

In the second lecture of our 'Diy biolab drivers license' course, students saw live how slime mold transfers nutrients within its body. Firstly the flow goes in one direction, after a while stops and then moves in another direction. Since this is how a slime mold grows and distributes nutrients to every part of its body, I wondered: what if the slime mold were to consume multicolored food—would it change its color as a result? And what if there were several different colors involved? Would distinct color boundaries be visible, or would there be soft transitions? Or would the slime mold simply turn a single, uniform color?

That's exactly why I started my experiments. For that I needed:

• slime mold
• Petri dishes
• oat flakes
• agar
• food coloring
• camera

My final goal was to film the process of growing with camera. With the video/timelapse It would be very clear to see how slime mold change colors. But in the end I decided to make a session of photography/micro photography instead of filming a video, mainly because of technical reasons.

First experiment (08.05)

During the first try it was important for me to understand my workflow in the lab and already test my idea practically.

First of all medium for slime mold had to be prapared. I'll use 2% agar solution.

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  Formula in BioLab for slime mold medium

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  All ingredients are prepared. Agar-agar, laboratory glassware for measurement and mixing, scale and spoon

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  Agar and water mixed together

After that agar must be heated and then poured into Petri dishes.

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  Heating agar

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  Sterile Petri dishes

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  Two Petri dishes filled with agar

When agar medium is ready it's time to put slime mold, oat flakes, and food coloring inside. Around two weeks before the experiment some of the students took slime mold with them to home, and I was one of them. During this time slime mold grew very well, and I'll use it as "mother culture" for my experiment.

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  "Mother culture" for my experiment

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I took some parts from the Mother Culture and placed them in two Petri dishes. For the coloring process I took liquid food coloring (four colors) and judging by their composition, I assume that slime mold should like this—since the dye consists primarily of syrup and sugar. After placing slime mold and oat flakes inside Petri dishes I made a couple of color drops on top of flakes.

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  Taking part of the Mother Culture

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  Liquid food coloring

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  Composition of food colorings (primarily made from sugar)

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  Placing everything in Petri dish

When Petri dished were ready, it was the time to prepare camera set-up for timelapse filming. After reading some manuals and instructions I was able to set settings, that camera makes one photo each minute. For the first experiment I decided to make 48 frames (48 minutes of filming), which in the end will be 2 seconds video. My teacher also suggested to feed mother culture to make it stronger for the future.

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  Camera set-up with placed Petri dishes

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  Feeding Mother Culture to make it stronger

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After filming I exported it to my laptop and made a video out of the footage. By the way, instead of 48 photos, there were somehow 96 on the memory card—and on the video itself, constant flashes were visible. I saw in the camera setting "Anti-flickering mode", so maybe I need to enable it next time.

Second Experiment (11.05)

Since I already understood what my workflow is like, now I could create more precise plan. I wanted to film around 11 hours of timelapse (660 frames), so I'll stay in the BioLab almost the whole day. When I arrived at 6am I wanted to check two Petri dishes from my first experiment and then decide if I'll continue with them or create new ones.

In Petri dishes I noticed that slime mold changed color only in two spots: with blue and green colors, but blue one was the most visible. I assume, that place with red drop was hard ro reach for the slime mold (drops were on top of oat flakes), and place with the yellow one... I don't even know actually if it's natural color of the culture or not. But the first experiment was exactly for proving some of my concerns and to understanf what to do next.

I decided to prepare everything once again, because this material won't give me result that I want in the end. Also, my plan with using strong culture failed —there were mold inside. That's why I'll use slime mold from the first experiment.

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  First subject after three days

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  Mold in Mother Culture after three days

I repeated all the steps from the first experiment. The only thing that was different is a way of coloring. This time, instead of yellow, I'll mix orange color (hopefully it will be more visible in the end), and I won't add drops of dye on top of the oat flakes: instead, I'll dye them completely. That way, the slime mold for sure will cover the dye.

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  Preparing agar again

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  Coloring oat flakes

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  Prepared second try

Here is a video. Despite I turned on "Anti-flickering mode" pictures in the end are too bright to see anything at all. From now on I decided to make a session of photography/micro photography instead of filming a video.

Third Experiment (11.05-18.05)

After taking a closer look into first Petri dishes it was clear, that Slime mold actually didn't change the color - only agar around the body of slime mold was colorful. I started looking in the internet successful examples about coloring Slime mold and found this forum page. People over there discessed a way of coloring Slime mold using iron oxide pigments, that are used in cosmetics, food packaging coloring and other diverse fields of applications. They supossed to be non-toxic, which means the slime mold might eat it. In the lab we found iron powder and also something red without a label.

The coloring process is pretty straightforward: cooking poridge first and when it still warm mix it with powder. That's exactly what I did and then I prepared three Petri dishes. One with only "iron powder", second with "red powder" and last one has both.

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  Iron powder and something red

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  Cooking poridge for coloring

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  Colored poridge

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  Three Petri dishes for third experiment

A week after (18.05) I came to check all Petri dishes that I had. Red powder seems to be the best result, despite the fact that I have no idea what it is.

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So I decided to buy a couple of Iron-oxide coloring powder and it should be delievered until 05.06.///