What’s Making Planaria Lose Their Heads?

N. Sheehan

Nicholas Sheehan, Mount Saint Mary College Senior (Photo by Gabriela Murphy-Goldberg)

by Gabriela Murphy-Goldberg

From the use of herbicides, industrially or commercially available, resistant strains of unwanted plant species are becoming more prevalent. This fuels a vicious cycle to where increased herbicide concentrations are being used to counteract these resistant strains. Furthermore, this excess herbicide solution is finding its way to aquatic environments secondary to run-off and overspray from cropland. Local research performed at Mount Saint Mary College by senior Nick Sheehan looks into the effects of a commercially available herbicide, Roundup, on the regeneration abilities of planaria. Mount Messenger decided to get a deeper insight as to what his research entailed.

Mount Messenger: How did you become interested in this idea to begin with?

Nick:  I became interested in the idea through the Developmental Biology class offered here at the Mount. Through lab exercises characterized by developing relevant laboratory experiments, I was part of a team which derived this idea. After completing the class, my faculty mentor Dr. Carl Hoegler and I were still very interested in the topic and biological processes, so I chose to pursue the idea as my research project.

Mount Messenger: Could you describe the research a bit for our readers?


Nick: My research looks at the effects herbicide has on a species of aquatic invertebrates, planaria, which are prone to exposure. Planaria have the ability to undergo epimorphic regeneration, which means that they can split in half and completely regenerate a new head or new tail. In my research, the heads of various subspecies of planaria are intentionally severed and observation of the effects sublethal concentrations of herbicide has on their ability to regenerate their head is observed. In addition, the effects the herbicide has on the regeneration of its nervous system is observed as well. I have characterized 5 stages of planaria head regeneration, which we believe has not been done before. Ultimately, the herbicide exposure has shown to have negative effects on the planaria’s capability to undergo complete head and nervous system regeneration. Now that we could conclude the herbicide impedes these processes, we began to be curious regarding what the herbicide’s mode of action is in causing the observed results. To assess the mode of action, protein samples are generated from herbicide exposed and non-herbicide exposed planaria at each stage of regeneration. The proteins are then analyzed by gel electrophoresis. This allows us to see if the herbicide causes the presence or absence of proteins based on their molecular weights. Currently, I am working with western blotting techniques in effort to identify a specific protein that is being affected by herbicide exposure.

Mount Messenger: What obstacles or difficulties did you run across in your research? How did you overcome them to reach your current conclusions thus far?

Nick: Difficulties that I have ran across in my research pertain to the fact that at this stage the research is still in its exploratory phase. As of now, we cannot find any published research relevant to this. The research is one of the first, if not the first to explore this idea. From this, I have overcome this difficulty by using the available knowledge and laboratory techniques to their fullest extent to provide insight on the subject and also to continuously lead the research in the direction it has been going.

Mount Messenger: What do you personally find most surprising or exciting or important about your work?

Nick:  What I personally find most exciting about my work is the fact that this is exploratory research which has no path previously defined by any other research. The findings of the research are always new and exciting.


Mount Messenger: What specific directions and applications do you think your research might or should go from here? What obstacles do you foresee in future research or development?

Nick: At this point, the research should go in the direction of detecting the specific proteins that are being affected by exposure to the herbicide through western blot technique. Here an obstacle exists in the availability of planaria specific antibodies for the western blot technique since the research is still exploratory or, cutting edge. If a planaria specific antibody is not available for a said protein; that said protein cannot be detected by western blotting. The potential application this research may hold is the identification of a commercially used environmental toxin to the aquatic environment.