1. Chemical Pharyngeal Amputation Inhibition of Asexual Reproduction
Implementation of Undergraduate Research Projects with Commercially Available Planarians for Non-Sciences Majors
Luis A Mata1, Jace P Valls1 & Paloma Valverde, PhD2
1. Biomedical Engineering Students; 2. Advisor and Professor, Sciences Department. WIT
Chemical Pharyngeal Amputation
Abstract
This poster describes a series of projects of increasing level of scientific inquiry that were accomplished by non-sciences majors using planarians as part of a 4-credits course named Directed Study in Biological Research at a primarily teaching institution in Boston, MA.
Goal of The Study
The goal of this study was to determine whether implementation of high level of scientific inquiry and data-driven research could be facilitated by encouraging non-sciences majors to use the scientific method and the engineering design process.
Bio406 – Directed Study in Biological Research
Biol406 is part of the minor in biology and bioinformatics offered by the Sciences Department. The course is based on authentic scientific research within an undergraduate teaching laboratory setting. Students are introduced to biotechnology techniques and common applications in medical biotechnology research and development. The topics are introduced by performing a combination of laboratory projects, discussing scientific publications and going on relevant field trips. Students meet with the professor three times per week for two hours each at the biology laboratory, and they also perform take-home projects (not described in this poster).
These experiments were done in a different strain of planarians when compared with the research articles (that used research clones and sophisticated laboratory equipment). When students attempted to reproduce the original research experiments using the scientific method, most of the planarians died.
Using the Scientific Method and The Engineering Design Method in Undergraduate Research Projects
Engineering students tend to approach daily life situations and problems in their profession using the Engineering design method; hence a combination of the scientific and engineering method was used in this course in order to conduct undergraduate research projects with planarians. With the scientific method, scientists develop experiments with the purpose of answering a question. Engineers use the engineering design process to create solutions to problems.
Experimental Design and Methods
Basic information about planarian biology and stem cells was introduced by asking students to use Pubmed to find and read review articles on planarian regeneration for in-class discussion.
During the initial stages of the course, students implemented the scientific method by performing simple regeneration experiments using commercially available planarians, different immobilization methods and cutting patterns of their choice.
Students were then asked to generate double-headed planarians and were encouraged to use the scientific method and the engineering design process as needed. Students chose the drugs praziquantel and ivermectin.
Ivermectin and Praziquantel were purchased from Sigma. Initially, students prepared Ivermectin and used it at 1 micromolar concentration, and Praziquantel at 90 micro-molar concentration in different strains of commercially available brown and black planarians (Carolina Biologicals, Wards).
Tails, heads, trunks or full bodies were kept in a small incubator at 22oC. Disposable scalpels and pasteurized spring water was purchased from Carolina Biologicals.
Results & Troubleshooting
Then, the students proceeded to implement a combination of the engineering design and scientific method to tune-up the experimental conditions and to come up with solutions to the problems encountered, including performing dose-response and time-course experiments for each drug investigated, and choosing the planarian strain that gave them the most reproducible results.
Subsequently, the experiments were repeated at the optimal concentrations determined by the students. Success was not an immediate step; students had to repeat the experiments multiple times and modify multiple variables including the time of exposure, number of samples, concentration of the chemicals, type and patterns in the cuts and environment conditions.
Overall, students were able to generate planarians with two-heads from trunks of Dugesia dorotocephala specimens and made videos of their movement and of the early stages of their regeneration.
Less than 25% of the experiments produced planarians with two heads. However students persevered and continued investigating possible factors that interfered with their “success rate”. They found both drugs temporarily inhibited planarian movement and asexual reproduction. Those effects would wear off after a while (if fresh drug was not added, or if the drug was replaced by water) and planarians with two heads would eventually separate into two pieces (with one head each). Students also found high dose of praziquantel resulted in chemical amputation of the pharynx and low dose promoted cannibalism in crowded culture plates.
Inhibition of Asexual Reproduction
Conclusions
Formative, summative assessments and learning reflections demonstrated that giving the freedom to use either the scientific method or the engineering design process to non-sciences majors can increase their motivation to get involved in data-driven biological research and empower them to become creative problem-solvers and avid readers of scientific literature. Students from non-science majors demonstrate that they have the aptitude and motivation to perform biology research studies within the course of a semester and work on their own publications once the course is completed.
Commercially available planarians are easy to use and inexpensive, and we plan on using them in future semesters to continue empowering non-sciences majors to get involved in data-driven biological research and increase their perseverance, creativity, problem-solving skills and scientific literacy.
References
Planarians as a Successful Undergraduate Teaching/Learning Model for Non-Sciences Majors
Planarians are non-parasitic flatworms with an extraordinary ability to regenerate missing body parts. The identification and regeneration of the missing body parts involves different signaling pathways including the WNT/beta catenin pathway. Students from non-science majors at WIT have shown great motivation to learn more about the planarians’ unique ability to regenerate body parts. Several planarian-related projects are being implemented in freshman biology courses since Summer 2014 and in research-like courses since Fall2012.