Survival of the Fittest- Using Natural Selection to Engineer Viruses

Hello everyone! Last week I briefly mentioned an activity that I had in mind for part of my maker challenge lesson plan. I promised that I would go more in depth the next week , so I have dedicated this post to explaining my natural selection of viruses activity. I have included the background and outline of the activity so that you can have an overview before looking at the activity itself.

Background

Imagine jumping into the perfect pool on a hot summer’s day. The water is cool, crisp and clear thanks to a filter that helps to keep it clean. Now, imagine jumping into the worst pool. It’s probably green, grimey, and gross. That grimey gunk that lines the sides of the pool is known as a biofilm. Biofilms are layers of bacteria or algae that grow on surfaces, and they form in lots of places: pools, shower tiles, and even your teeth! Biofilms also tend to form on water filters, so if you don’t replace the filters regularly, bacteria can leak into your pool or even the water you drink! But, what if we could remove this biofilm without needing to replace the filter or releasing toxic chemicals into the water? Scientists have found a seemingly unlikely hero in viruses. Just like there are viruses that infect us and make us sick, there are some viruses that specifically infect bacteria. These viruses have specific structures on their surface that help them attach to the bacteria. Some even have special abilities to kill bacteria even faster using special enzymes. The problem is that there is more than one type of bacteria in these biofilms, and viruses are usually very specific to one type of bacteria. Scientists need a way to engineer viruses so that they can infect and kill as many different bacteria as possible. That’s when you come in!

In this activity, students will experience how some scientists are using the principles of natural selection to engineer viruses that infect multiple bacterial hosts. By sequentially changing the environment through switching out the type of bacteria, over the course of a few generations, scientists are left with viruses that can infect all of the different bacterial hosts. This model will help students visualize natural selection as well as the process of viral infection.

Figure 1: Sequential Multihost Isolation Method used by scientists
Materials
  • At least 4 styrofoam balls/blocks (“viruses”)
  • At least 20 sets of velcro circles (“surface proteins” and “bacteria”)
  • Double Sided (or single sided, folded) tape (“surface proteins”)
  • At least 10 small fuzzy pom poms (“bacteria”)
  • At least 10 small squares of paper (“bacteria”)
  • 1 container
Setup

First, you will need to attach the surface proteins to the viruses as outlined below:

  • Virus A: soft velcro surface proteins
  • Virus B: spikey velcro surface proteins
  • Virus C: soft & spikey velcro surface proteins
  • Virus D: double sided tape surface proteins (or single sided, folded as pictured)
  • Virus E: soft velcro, spikey velcro, and tape proteins
Figure 2: “viruses” with their “surface markers”

For this demonstration you will be walking your students through the process of introducing your viruses to different bacterial environments. An outline of these different environments and the expected outcomes is shown below:

 

Figure 3: Outline of Virus Natural Selection Activity
Figure 4: Outcome of Environment 1- fuzzy bacteria. Virus B, C, and E can attach to the fuzzy bacteria, but Virus A and D cannot. If they cannot attach, they cannot reproduce, so they are removed from the population for the next Environment.
Figure 5: Outcome of Environment 2- spikey velcro bacteria. Virus C & E can attach to the spikey bacteria, but Virus B cannot. Since it cannot attach, Virus B is removed from the population.
Figure 6: Outcome of Environment 3- paper bacteria. Virus E can attach to the paper bacteria, but Virus C cannot. Since Virus E is the one that can infect all of the bacteria, this is the virus scientists will select to use to fight the biofilms.
Challenges/Future Directions
  • The tape was actually somewhat sticking to the fuzzy pom pom bacteria. Perhaps a different type of surface protein or bacteria will need to be used? Any advice is appreciated.
  • It could be interesting to ask students which method they think would work better, sequentially exposing them to the bacteria or exposing them to all of the different bacteria at the same time (Figure 7).
  • Merits/detriments of actually showing the viruses reproducing. Should they add one more of each of the viruses that attached? This could take extra time to prepare and explain but it could also be more accurate in showing natural selection.
Figure 7: Potential option to give students with the natural selection method of isolating multivalent viruses (viruses that can infect multiple types of bacteria). As opposed to the sequential multihost method which exposes viruses to only one host at a time, this method exposes the viruses to all of the types of bacteria at one time.

 

Thank you for taking the time to read my lesson idea! Any and all comments/advice is much appreciated!

5 thoughts on “Survival of the Fittest- Using Natural Selection to Engineer Viruses”

  1. This lesson is pretty cool! I’m also working with viruses but it never crossed my mind to use them to show Natural Selection! This is awesome!

    1. Thanks Mariana! 🙂 I would love to learn more about your research and your plans for applying viruses to your class!

      1. In my research we are utilizing viruses for gene therapy but we are focusing on making the virus only enter targeted cells. Since I teach Forensic Science I though of going with the ” I Am Legend” kind of theme (I’m not sure if you have seen the movie but they use a virus for therapy but the virus ends up attaching to other cells in the body and creates zombies/vampires.) Well, I’m going to be having my students create a virus and they are going to modify its outer structure in order for the virus to only attach to one type of cell. I haven’t worked out exactly what I’m going to be using for the materials but I’m thinking pom poms, styrofoam balls and sticks, velcro, etc.

        1. That sounds exactly like the maker challenge I was thinking of incorporating! My original plan was to have students design their virus first and then show them how scientists in my lab use natural selection to isolate the viruses they need rather than doing all of the work of genetically modifying them. But I was thinking that in the first part I could maybe spiral in some of what they already learned about DNA so that they have to develop the right code of DNA based on the different proteins they want on the coat of their virus (for instance, pom pom is coded by AATGCA or something like that). I know Christina mentioned to me that she has a lesson already made that sounds similar to what you want to do (but it hasn’t been published yet), so you could try reaching out to her to see what she has too!

      2. In my research we are utilizing viruses for gene therapy but we are focusing on making the virus only enter targeted cells. Since I teach Forensic Science I though of going with the ” I Am Legend” kind of theme (I’m not sure if you have seen the movie but they use a virus for therapy but the virus ends up attaching to other cells in the body and creates zombies/vampires.) Well, I’m going to be having my students create a virus and they are going to modify its outer structure in order for the virus to only attach to one type of cell. I haven’t worked out exactly what I’m going to be using for the materials but I’m thinking pom poms, styrofoam balls and sticks, velcro, etc.
        I haven’t really gather the materials to see if it would work yet but I feel like it would be a cool project where they can use their creativity.

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