Research-Intro: New Update- Isopods

Observations on Pill Bugs in Different Environments

Due to an issue of not knowing the size of planarians before shipping; we are now unable to perform the regeneration experiment.

Our new experiment will be focusing on the behavior of pill bugs in different environments. Part A of our experiment involves a choice chamber containing organic soil (the control), organic liquid fertilizer, organic pesticide, and Starbucks brand coffee grounds. The fertilizer and pesticide will be transferred into spray bottles containing 2.4 tsp of fertilizer to 350 mL of water and 38mL of pesticide to 355mL of water. We using a one to one ratio for coffee and soil as one of the chambers. For each trial, four pill bugs will be placed into the chamber and the behavior will be observed in one minute increments for ten minutes. In part B of our experiment we will be testing toxicity of fertilizer in four environments; one being water (control), low, medium, and high toxicity. We will be using the same fertilizer bottle from part A and increasing number of sprays per environment. In addition, we plan to use wild-caught pill bugs in both parts of the experiment to compare them to the lab population.

Part A hypothesis: Different substances in the soil will affect the behavior of the pill bugs.

Prediction: The pill bugs will visit the water the most over the other environments.

Part B hypothesis: The concentration of fertilizer in the soil will affect the survival or lifespan of the pill bugs.

Prediction: In high concentration all the pill bugs will die, in medium concentration some of the pill bugs will die, and in the low concentrated and water environment all the pill bugs will survive.

The Regeneration of Brown Planaria

This experiment was planned by Auryana Ashoori, Tien Pham, Karley Quibilan, and Hannah Zaini.

Figure 1. The test subject of our experiment, Brown Planaria.

Background:

The remarkable feat of regenerating body parts has only been seen among a few organisms. Of these organisms, planaria in the phylum platyhelminthes have been shown to regrow more than half of their body when cut. They are even able to grow a new head from a detached body part, therefore forming a new planaria with identical DNA. Planaria have even been documented to regenerate completely out of 1/100th and even 1/200th of their original body size (playing with wormies 2018). In this experiment, our group’s purpose is to examine and understand the ability of the brown planaria to regenerate new heads and tails.

Plan:

Our group's plan for the experiment is to create two parts: part A and part B. In part A we will change how we cut the planaria while observing the patterns of regeneration in response to a cut (Figure 1). In part B, we will cut all the planaria in the same way, while changing what we feed the organisms. For both parts of the experiment, the environment will be controlled using the same aquatic material for all samples. Within part B, we will feed one group boiled egg yolk, while not feeding the other group. We will then observe the patterns of regeneration in response to food. In Figure 2, the far right arrow represents the cut we’ll use in part B.

Hypothesis:

The hypothesis tested in part A of the experiment is: Cutting the planaria at different locations along their body will result in different patterns of regeneration. The null hypothesis would be the different cuts will not affect the regeneration pattern.  

Prediction:

We predict that any cut along the body axis that severs the planaria into two parts, will result in two new daughter planaria. This means that each part will regrow missing body parts, even a new head, in order to become a whole planaria. We also predict that in part B of the experiment, feeding the planaria will result in a faster regeneration in comparison to not feeding them.

Figure 2. The four types of cuts we will be making along the body of our brown planaria in part A.

Reasoning:

We decided to do this research project because we all found the idea of regeneration fascinating. Planaria are platyhelminthes, which is a phylum that we have been learning about. We thought this would apply well to the material we have learned in class, specifically watching hox genes in action. We also found planaria to be really cute and wanted to watch them grow.

Challenges:

Some challenges we have encountered so far is finding the balance between having enough trials and having too many trials. Cutting a worm in half will result in two new worms, therefore doubling the worms we need to observe. While we want enough trials, we still need to be able to observe all the worms in one lab period. Although we tried to resolve this, we may still run into issues during lab.

References:

Novikova EL, Bakalenko NI, Nesterenko AY, Kulakova MA. Expression of Hox genes during regeneration of nereid polychaete Alitta (Nereis) virens (Annelida, Lophotrochozoa). EvoDevo. 2013 [accessed 2018 Feb 8];4(1).

Playing with wormies. Baldscientist. 2014 Oct 19 [accessed 2018 Feb 8]. https://baldscientist.wordpress.com/2011/09/23/playing-with-wormies/

Rink JC. Stem cell systems and regeneration in planaria . Development Genes and Evolution. 2013 Mar [accessed 2018 Feb 8]. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3552358/

Tal Shomrat, and Michael Levin. 2 July 2013. An Automated Training Paradigm Reveals Long-term Memory in Planaria and its Persistence Through Head Regeneration. Journal of Experimental Biology 2013 [internet]. doi: 10.1242/jeb.087809