Science Buddies: "Ask an Expert"

Hi,
I am thinking of doing an experiment that replicates the neutralisation of Jellyfish venom in the presence of vinegar.

Obviously, I am unable to use actual Jellyfish venom, but I found that Bacillus thuringiensis exotoxin (which is used as an insecticide) shares a similar pore-forming mechanism as the proteins present in Jellyfish sting toxins.

I am struggling to come up with a continuous research question for my experiment. I was thinking of testing How the concentration of vinegar effects the rate of denaturation of the Bacillus thuringiensis exotonin, but I don't know if this is too simple. I am also unsure how I would be able to tell when the protein is denatured, as I will be dissolving it in water.

Any help would be greatly appreciated

Thanks!!

Hi jennys247,

The project you've described is original and very interesting. I think you're on the right track.

Science Buddies has a science fair project guide with some helpful information on developing your project question:

https://www.sciencebuddies.org/science- ... t-question

Testing for the degree of protein denaturation is outside of my expertise. You might get better answers if you post on the Life, Earth and Social Sciences forum. Topics there include biochemistry and biology.

Based on some online searching, it appears that there are some spectrophotometric methods available for this kind of work. But all of these methods require specialized lab equipment. Some articles that mention these tests are at the following links:

https://pdfs.semanticscholar.org/a0b2/d ... 3bc7a8.pdf

https://hal.archives-ouvertes.fr/hal-00895648/document

https://journals.plos.org/plosone/artic ... ne.0050380

Color and consistency changes due to denaturation of some proteins are easily seen. For example, egg white (albumin) changes from a clear liquid to a white solid when cooked. Some ideas about testing this denaturation are discussed here:

viewtopic.php?t=16843

I hope this helps. Please post again if you have more questions.

A. Norman

moderator note: I've cross-posted this topic on the 9-12 Life Sciences since this seems to involve both Physical and Life Sciences.

This is outside my expertise, but it seems that vinegar might not break down the venom directly. According to https://www.popsci.com/how-to-treat-jellyfish-sting/, vinegar inactivates the nematocysts, preventing further release of venom. Looking into that process might also be an interesting avenue.

Hi,

Thanks for all your help so far!

I have decided to change the question to solving for the value of ΔG for the denaturation of the protein by testing the effects of different concentrations of urea. I will be measuring the denaturation using a spectrophotometer to get the value for absorbance.

I will be using a method that I found online (the link for it is: http://www2.onu.edu/~k-broekemeier/Chem ... rotein.pdf ).

I understand the maths and graphs needed in order to obtain a value for ΔG, however, I still have a few questions about ..,

1. How would I make the 9M Urea solutions (as in what amounts of Urea solid and water would I have to mix)
2. How would I calculate the concentration of urea (as in the results table they give you the heading and space to work the value out).

It would be greatly appreciated if you could help answer some of my questions!

Thank you

Hi Jenny,
Have you made any progress while waiting?
The link you posted looks like an experiment conducted in a university lab, one equipped with a spectrometer. Do you have access to one and someone who can show you how to use it? At first glance this looks to be a very equipment-necessary experiment for a high school project.
Also, I do not think you will be able to purchase and properly store myoglobin. You may still find the experiment rewarding but much more achievable by measuring the changes in protein urea solutions using an easier method. One common method is to observe changes in an egg. Maybe you could do something like modify this experiment:https://www.education.com/science-fair/ ... -proteins/ but using urea solutions.
9M means 9 moles per Liter, which is simply how many molecules of urea are in 1 liter of solution. (1 mole=602,200,000,000,000,000,000,000 or 6.022x10^23 for short). If you have adult help, I think you can purchase solid urea to dissolve yourself. However, probably what you will end up needing to do is purchase some urea, which will not be as concentrated as in this experiment because it is a dangerous chemical so only labs with safety equipment should buy it at full strength. Then, you can experiment on the egg with different amounts of that purchased solution, diluted into buffer solution. You cannot just use water.
A buffer solution simply makes sure the urea does not turn your solution too acidic or basic. You may be able to purchase a buffer solution powder to mix with water. You could maybe use artificial seawater? or a common lab one is phosphate-buffered saline.
Sorry this isn't exactly what you originally thought of. I would definitely check with your biology teachers to see if they have the resources necessary to do this and are willing to help you at school, otherwise the experiment you linked to will be impossible at home.
Good luck!

Hi there,

I have a more detailed instruction about making 9M urea solution:
Solid urea has the chemical formula CH4N2O. If you dissolve 60.06g of CH4N2O in a final volume of 1 litre, you have made a 1M CH4N2O solution. So multiply it by 9 if you want to make a 9M solution.

I hope it helps.

Best,
Elise